#### Sample records for standard chromatographic techniques

1. Chromatographic screening techniques in systematic toxicological analysis.

Science.gov (United States)

Drummer, O H

1999-10-15

A review of techniques used to screen biological specimens for the presence of drugs was conducted with particular reference to systematic toxicological analysis. Extraction systems of both the liquid-liquid and solid-phase type show little apparent difference in their relative ability to extract a range of drugs according to their physio-chemical properties, although mixed-phase SPE extraction is a preferred technique for GC-based applications, and liquid-liquid were preferred for HPLC-based applications. No one chromatographic system has been shown to be capable of detecting a full range of common drugs of abuse, and common ethical drugs, hence two or more assays are required for laboratories wishing to cover a reasonably comprehensive range of drugs of toxicological significance. While immunoassays are invariably used to screen for drugs of abuse, chromatographic systems relying on derivatization and capable of extracting both acidic and basic drugs would be capable of screening a limited range of targeted drugs. Drugs most difficult to detect in systematic toxicological analysis include LSD, psilocin, THC and its metabolites, fentanyl and its designer derivatives, some potent opiates, potent benzodiazepines and some potent neuroleptics, many of the newer anti-convulsants, alkaloids colchicine, amantins, aflatoxins, antineoplastics, coumarin-based anti-coagulants, and a number of cardiovascular drugs. The widespread use of LC-MS and LC-MS-MS for specific drug detection and the emergence of capillary electrophoresis linked to MS and MS-MS provide an exciting possibility for the future to increase the range of drugs detected in any one chromatographic screening system.

2. Chromatographic Techniques for Rare Earth Elements Analysis

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Chen, Beibei; He, Man; Zhang, Huashan; Jiang, Zucheng; Hu, Bin

2017-04-01

The present capability of rare earth element (REE) analysis has been achieved by the development of two instrumental techniques. The efficiency of spectroscopic methods was extraordinarily improved for the detection and determination of REE traces in various materials. On the other hand, the determination of REEs very often depends on the preconcentration and separation of REEs, and chromatographic techniques are very powerful tools for the separation of REEs. By coupling with sensitive detectors, many ambitious analytical tasks can be fulfilled. Liquid chromatography is the most widely used technique. Different combinations of stationary phases and mobile phases could be used in ion exchange chromatography, ion chromatography, ion-pair reverse-phase chromatography and some other techniques. The application of gas chromatography is limited because only volatile compounds of REEs can be separated. Thin-layer and paper chromatography are techniques that cannot be directly coupled with suitable detectors, which limit their applications. For special demands, separations can be performed by capillary electrophoresis, which has very high separation efficiency.

3. Standard Format for Chromatographic-polarimetric System small samples assessment

International Nuclear Information System (INIS)

Naranjo, S.; Fajer, V.; Fonfria, C.; Patinno, R.

2012-01-01

The treatment of samples containing optically active substances to be evaluated as part of quality control of raw material entering industrial process, and also during the modifications exerted on it to obtain the desired final composition is still and unsolved problem for many industries. That is the case of sugarcane industry. Sometimes the troubles implied are enlarged because samples to be evaluated are not bigger than one milliliter. Reduction of gel beds in G-10 and G-50 chromatographic columns having an inner diameter of 16 mm, instead of 25, and bed heights adjustable to requirements by means of sliding stoppers to increase analytical power were evaluated with glucose and sucrose standards in concentrations from 1 to 10 g/dL, using aliquots of 1 ml without undesirable dilutions that could affect either detection or chromatographic profile. Assays with seaweed extracts gave good results that are shown. It is established the advantage to know concentration of a separated substance by the height of its peak and the savings in time and reagents resulting . Sample expanded uncertainty in both systems is compared. It is also presented several programs for data acquisition, storing and processing. (Author)

4. Analytical method for the identification and assay of 12 phthalates in cosmetic products: application of the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques".

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Gimeno, Pascal; Maggio, Annie-Françoise; Bousquet, Claudine; Quoirez, Audrey; Civade, Corinne; Bonnet, Pierre-Antoine

2012-08-31

Esters of phthalic acid, more commonly named phthalates, may be present in cosmetic products as ingredients or contaminants. Their presence as contaminant can be due to the manufacturing process, to raw materials used or to the migration of phthalates from packaging when plastic (polyvinyl chloride--PVC) is used. 8 phthalates (DBP, DEHP, BBP, DMEP, DnPP, DiPP, DPP, and DiBP), classified H360 or H361, are forbidden in cosmetics according to the European regulation on cosmetics 1223/2009. A GC/MS method was developed for the assay of 12 phthalates in cosmetics, including the 8 phthalates regulated. Analyses are carried out on a GC/MS system with electron impact ionization mode (EI). The separation of phthalates is obtained on a cross-linked 5%-phenyl/95%-dimethylpolysiloxane capillary column 30 m × 0.25 mm (i.d.) × 0.25 mm film thickness using a temperature gradient. Phthalate quantification is performed by external calibration using an internal standard. Validation elements obtained on standard solutions, highlight a satisfactory system conformity (resolution>1.5), a common quantification limit at 0.25 ng injected, an acceptable linearity between 0.5 μg mL⁻¹ and 5.0 μg mL⁻¹ as well as a precision and an accuracy in agreement with in-house specifications. Cosmetic samples ready for analytical injection are analyzed after a dilution in ethanol whereas more complex cosmetic matrices, like milks and creams, are assayed after a liquid/liquid extraction using ter-butyl methyl ether (TBME). Depending on the type of cosmetics analyzed, the common limits of quantification for the 12 phthalates were set at 0.5 or 2.5 μg g⁻¹. All samples were assayed using the analytical approach described in the ISO 12787 international standard "Cosmetics-Analytical methods-Validation criteria for analytical results using chromatographic techniques". This analytical protocol is particularly adapted when it is not possible to make reconstituted sample matrices. Copyright © 2012

5. Gas chromatographic isolation technique for compound-specific radiocarbon analysis

International Nuclear Information System (INIS)

Uchida, M.; Kumamoto, Y.; Shibata, Y.; Yoneda, M.; Morita, M.; Kawamura, K.

2002-01-01

Full text: We present here a gas chromatographic isolation technique for the compound-specific radiocarbon analysis of biomarkers from the marine sediments. The biomarkers of fatty acids, hydrocarbon and sterols were isolated with enough amount for radiocarbon analysis using a preparative capillary gas chromatograph (PCGC) system. The PCGC systems used here is composed of an HP 6890 GC with FID, a cooled injection system (CIS, Gerstel, Germany), a zero-dead-volume effluent splitter, and a cryogenic preparative collection device (PFC, Gerstel). For AMS analysis, we need to separate and recover sufficient quantity of target individual compounds (>50 μgC). Yields of target compounds from C 14 n-alkanes to C 40 to C 30 n-alkanes and approximately that of 80% for higher molecular weights compounds more than C 30 n-alkanes. Compound specific radiocarbon analysis of organic compounds, as well as compound-specific stable isotope analysis, provide valuable information on the origins and carbon cycling in marine system. Above PCGC conditions, we applied compound-specific radiocarbon analysis to the marine sediments from western north Pacific, which showed the possibility of a useful chronology tool for estimating the age of sediment using organic matter in paleoceanographic study, in the area where enough amounts of planktonic foraminifera for radiocarbon analysis by accelerator mass spectrometry (AMS) are difficult to obtain due to dissolution of calcium carbonate. (author)

6. Experimental studies of uncertainties associated with chromatographic techniques.

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Barwick, V J; Ellison, S L; Lucking, C L; Burn, M J

2001-05-25

The paper describes experiments for the evaluation of uncertainties associated with a number of chromatographic parameters. Studies of the analysis of vitamins by HPLC illustrate the estimation of the uncertainties associated with experimental "input" parameters such as the detector wavelength, column temperature and mobile phase flow-rate. Experimental design techniques, which allow the efficient study a number of parameters simultaneously, are described. Multiple linear regression was used to fit response surfaces to the data. The resulting equations were used in the estimation of the uncertainties. Three approaches to uncertainty calculation were compared--Kragten's spreadsheet, symmetric spreadsheet and algebraic differentiation. In cases where non-linearity in the model was significant, agreement between the uncertainty estimates was poor as the spreadsheet approaches do not include second-order uncertainty terms.

7. Temperature Control of Gas Chromatograph Based on Switched Delayed System Techniques

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Xiao-Liang Wang

2014-01-01

Full Text Available We address the temperature control problem of the gas chromatograph. We model the temperature control system of the gas chromatograph into a switched delayed system and analyze the stability by common Lyapunov functional technique. The PI controller parameters can be given based on the proposed linear matrix inequalities (LMIs condition and the designed controller can make the temperature of gas chromatograph track the reference signal asymptotically. An experiment is given to illustrate the effectiveness of the stability criterion.

8. Statistical designs and response surface techniques for the optimization of chromatographic systems.

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Ferreira, Sergio Luis Costa; Bruns, Roy Edward; da Silva, Erik Galvão Paranhos; Dos Santos, Walter Nei Lopes; Quintella, Cristina Maria; David, Jorge Mauricio; de Andrade, Jailson Bittencourt; Breitkreitz, Marcia Cristina; Jardim, Isabel Cristina Sales Fontes; Neto, Benicio Barros

2007-07-27

This paper describes fundamentals and applications of multivariate statistical techniques for the optimization of chromatographic systems. The surface response methodologies: central composite design, Doehlert matrix and Box-Behnken design are discussed and applications of these techniques for optimization of sample preparation steps (extractions) and determination of experimental conditions for chromatographic separations are presented. The use of mixture design for optimization of mobile phases is also related. An optimization example involving a real separation process is exhaustively described. A discussion about model validation is presented. Some applications of other multivariate techniques for optimization of chromatographic methods are also summarized.

9. Secretory immunoglobulin purification from whey by chromatographic techniques.

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Matlschweiger, Alexander; Engelmaier, Hannah; Himmler, Gottfried; Hahn, Rainer

2017-08-15

Secretory immunoglobulins (SIg) are a major fraction of the mucosal immune system and represent potential drug candidates. So far, platform technologies for their purification do not exist. SIg from animal whey was used as a model to develop a simple, efficient and potentially generic chromatographic purification process. Several chromatographic stationary phases were tested. A combination of two anion-exchange steps resulted in the highest purity. The key step was the use of a small-porous anion exchanger operated in flow-through mode. Diffusion of SIg into the resin particles was significantly hindered, while the main impurities, IgG and serum albumin, were bound. In this step, initial purity was increased from 66% to 89% with a step yield of 88%. In a second anion-exchange step using giga-porous material, SIg was captured and purified by step or linear gradient elution to obtain fractions with purities >95%. For the step gradient elution step yield of highly pure SIg was 54%. Elution of SIgA and SIgM with a linear gradient resulted in a step yield of 56% and 35%, respectively. Overall yields for both anion exchange steps were 43% for the combination of flow-through and step elution mode. Combination of flow-through and linear gradient elution mode resulted in a yield of 44% for SIgA and 39% for SIgM. The proposed process allows the purification of biologically active SIg from animal whey in preparative scale. For future applications, the process can easily be adopted for purification of recombinant secretory immunoglobulin species. Copyright © 2017 Elsevier B.V. All rights reserved.

10. Isolation and purification of plant secondary metabolites using column-chromatographic technique

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Vivek K. Bajpai

2016-12-01

Full Text Available Chromatographic techniques have significant role in natural products chemistry as well as contribute dramatically in the discovery of novel and innovative compounds of pharmaceutical and biomedical importance. This study focused on step-by-step visual demonstration of fractionation and isolation of biologically active plant secondary metabolites using column-chromatographic techniques. Isolation of bioactive compounds using column-chromatographic involves: a Preparation of sample; b Packing of column; c Pouring of sample into the column; d Elution of fractions; and e Analysis of each fractions using thin layer chromatography. However, depending on nature of research, compounds can be further purified using high performance liquid chromatography (HPLC, and nuclear magnetic resonance (NMR spectral analyses.

11. Pharmacognostic Screening of Piper trichostachyon Fruits and its Comparative Analysis with Piper nigrum Using Chromatographic Techniques.

Science.gov (United States)

2016-05-01

Piper trichostachyon is a wild, endemic Piper species from Western Ghats of India. The folklore healers of Belagavi region use this plant, similar to Piper nigrum. The present study investigates the comparison between P. nigrum and P. trichostachyon using pharmacognostic parameters. Pharmacognostic evaluation was carried out in terms of morphological, microscopic characters, and phytochemical analysis using standard methods. Comparative physicochemical analysis between P. trichostachyon and P. nigrum was also carried out through estimation of micro-macro nutrients, high-performance thin layer chromatography (HPTLC) investigation and using piperine as a marker compound for reversed phase-ultra flow liquid chromatographic (RP-UFLC) technique. P. trichostachyon grows in the forests, and the fruits are morphologically similar to P. nigrum fruits, so the name in Kannada "Kaadu Kalu menasu" (wild/forest black pepper). The microscopy revealed the presence of stone cells, starch grains, oil cells and globules, beaker cells, and yellowish brown pigment layer, parenchymatous cells. The presence of alkaloids, oil, and tannins were observed in P. trichostachyon fruits. The HPTLC studies visibly indicated differences among two species with 12 peaks and varied banding pattern. RP-UFLC results showed less amount of piperine in P. trichostachyon (0.05 ± 0.002 mg/g) than in P. nigrum (16.14 ± 0.807 mg/g). The study reports on pharmacognostic parameters of P. trichostachyon for the 1(st) time and will be useful for the identification and authentication. The comparative HPTLC and RP-UFLC studies resolve the differentiation impasse among two species. However, further biological efficacy studies are required to establish its use in traditional medicine. Piper trichostachyon grows in the forests, and the fruits are morphologically similar to Piper nigrum fruitsThe microscopy of P. trichostachyon revealed the presence of stone cells, starch grains, oil cells and globules, beaker cells

12. Determination of biologically active phenols and polyphenols in various objects by chromatographic techniques

International Nuclear Information System (INIS)

Kochetova, M V; Semenistaya, E N; Larionov, Oleg G; Revina, A A

2007-01-01

Chromatographic techniques for determination of biologically active phenols and polyphenols are considered. Various methods for sample preparation and detection are compared. The advantages of high performance liquid chromatography with spectrophotometric detection for determination of antioxidants are demonstrated. Data on determination of biologically active phenols and polyphenols published in the period from 1995 to 2005 are analysed.

13. Role of advances in chromatographic techniques in phytochemistry.

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Marston, Andrew

2007-01-01

Chromatography is the lynchpin of phytochemistry and is the key to obtaining pure compounds for structure elucidation, for pharmacological testing or for development into therapeuticals. It also plays a fundamental role as an analytical technique for quality control and standardisation of phytotherapeuticals. Although liquid chromatography is barely 100 years old, an extraordinary variety of instrumental and ancillary equipment is available, notably in the domain of high-performance liquid chromatography. It is impossible to touch all areas of chromatography in such a review but certain areas are worthy of mention: HPLC, HPTLC, UPLC and countercurrent chromatography. Another important addition has been the development of hyphenated techniques involving HPLC: LC/UV, LC/MS, LC/MS(n) and LC/NMR. These are indispensable nowadays for the early detection and identification of compounds in crude plant extracts.

14. Analysis of the Mechanism of Gram Differentiation by Use of a Filter-Paper Chromatographic Technique.

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Bartholomew, J W; Cromwell, T; Gan, R

1965-09-01

Bartholomew, J. W. (University of Southern California, Los Angeles), Thomas Cromwell, and Richard Gan. Analysis of the mechanism of Gram differentiation by use of a filter-paper chromatographic technique. J. Bacteriol. 90:766-777. 1965.-Data are presented which demonstrate that the mechanism of gram-positivity could not be due solely to factors such as a single, specific gram-positive substrate, specific affinities of crystal violet for certain cellular components, a specific crystal violet-iodine-substrate complex, or to any specific characteristic of the dye, iodine, or solvent molecules. Ruptured cells of gram-positive organisms stain gram-negatively when subjected to a standard Gram-stain procedure. However, when stained fragments of broken cells were deposited in thick layers on the surface of filter-paper strips and exposed to decolorizers, the rate of dye release correlated with the Gram characteristic of the intact cell. Therefore, the intact cell in itself is not an absolute requirement for Gram differentiation. The data are interpreted as indicating that the mechanism of Gram differentiation primarily involves the rate of permeation of molecules (dye, iodine, solvent) through the interstitial spaces of cell-wall material.

15. Quantitative Analysis of Resorcinol from Marketed Hair Tonic Using Liquid Chromatographic Technique

OpenAIRE

2014-01-01

Quantitative estimation of resorcinol from marketed pharmaceutical formulation has been reported in this study. Resorcinol as a pharmaceutical ingredient has a broad spectrum of application but its application is limited due to its toxic side effects. Method for the accurate estimation of resorcinol is therefore essential. In the current study we have developed a chromatographic technique for its estimation from a marketed hair tonic meant for the treatment of several dermatological diseases ...

16. On-line coupling of supercritical fluid extraction and chromatographic techniques.

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Sánchez-Camargo, Andrea Del Pilar; Parada-Alfonso, Fabián; Ibáñez, Elena; Cifuentes, Alejandro

2017-01-01

This review summarizes and discusses recent advances and applications of on-line supercritical fluid extraction coupled to liquid chromatography, gas chromatography, and supercritical fluid chromatographic techniques. Supercritical fluids, due to their exceptional physical properties, provide unique opportunities not only during the extraction step but also in the separation process. Although supercritical fluid extraction is especially suitable for recovery of non-polar organic compounds, this technique can also be successfully applied to the extraction of polar analytes by the aid of modifiers. Supercritical fluid extraction process can be performed following "off-line" or "on-line" approaches and their main features are contrasted herein. Besides, the parameters affecting the supercritical fluid extraction process are explained and a "decision tree" is for the first time presented in this review work as a guide tool for method development. The general principles (instrumental and methodological) of the different on-line couplings of supercritical fluid extraction with chromatographic techniques are described. Advantages and shortcomings of supercritical fluid extraction as hyphenated technique are discussed. Besides, an update of the most recent applications (from 2005 up to now) of the mentioned couplings is also presented in this review. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

17. Liquid Chromatographic-Chemometric Techniques for the Simultaneous HPLC Determination of Lansoprazole, Amoxicillin and Clarithromycin in Commercial Preparation.

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Aktas, A Hakan; Saridag, Ayse Mine

2017-09-01

Two multivariate calibration-prediction techniques, principal component regression (PCR) and partial least-squares regression (PLSR) were applied to the chromatographic multicomponent analysis of the drug containing lansoprazole (LAN), clarithromycin (CLA) and amoxicillin (AMO). Optimum chromatographic separation of LAN, CLA and AMO with atorvastatin as the internal standard (IS) was obtained by using Xterra® RP18 column 5 μm 4.6 × 250 mm2, and 25 mM ammonium chloride buffer prepared ammonium chloride, acetonitrile and bidistilled water (45:45:10 v/v) as the mobile phase at flow rate 1.0 mL/min. The high pressure liquid chromatography data sets consisting of the ratios of analyte peak areas to the IS peak area were obtained by using diode array detector detection at five wavelengths (205, 210, 215, 220 and 225 nm). LC-chemometric calibration for LAN, CLA and AMO were separately constructed by using the relationship between the peak-area ratio and training sets for each analyte. A series of synthetic solutions containing different concentrations of LAN, CLA and AMO were used to check the prediction ability of the PCR and PLS. Both of the two-chemometric methods in this study can be satisfactorily used for the quantitative analysis and for dissolutions tests of multicomponent commercial drug. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

18. Determination of Pu and U isotopes in safeguard swipe sample with extraction chromatographic techniques.

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Lee, M H; Park, J H; Oh, S Y; Ahn, H J; Lee, C H; Song, K; Lee, M S

2011-10-30

A simple and reliable separation method of plutonium and uranium was developed using extraction chromatographic techniques. Using the separation method of plutonium and uranium developed in this study, recoveries of plutonium and uranium were compared with those by commercial separation methods of Pu and U. The redox reactions of hydrogen peroxide with plutonium in a nitric acid medium were investigated by UV-vis-NIR absorption spectroscopic techniques. The separation method of Pu and U isotopes with the UTEVA resin updated in this study could be effective to measure quantitatively nano- and picogram amounts of uranium and plutonium in swipe samples using isotope dilution thermal ionization mass spectrometry (ID-TIMS). Copyright Â© 2011 Elsevier B.V. All rights reserved.

19. Use of adsorption and gas chromatographic techniques in estimating biodegradation of indigenous crude oils

International Nuclear Information System (INIS)

Kokub, D.; Allahi, A.; Shafeeq, M.; Khalid, Z.M.; Malik, K.A.; Hussain, A.

1993-01-01

Indigenous crude oils could be degraded and emulsified upto varying degree by locally isolated bacteria. Degradation and emulsification was found to be dependent upon the chemical composition of the crude oils. Tando Alum and Khashkheli crude oils were emulsified in 27 and 33 days of incubation respectively. While Joyamair crude oil and not emulsify even mainly due to high viscosity of this oil. Using adsorption chromatographic technique, oil from control (uninoculated) and bio degraded flasks was fractioned into the deasphaltened oil containing saturate, aromatic, NSO (nitrogen, sulphur, oxygen) containing hydrocarbons) and soluble asphaltenes. Saturate fractions from control and degraded oil were further analysed by gas liquid chromatography. From these analyses, it was observed that saturate fraction was preferentially utilized and the crude oils having greater contents of saturate fraction were better emulsified than those low in this fraction. Utilization of various fractions of crude oils was in the order saturate> aromatic> NSO. (author)

20. A novel strategy for quantitative analysis of the formulated complex system using chromatographic fingerprints combined with some chemometric techniques.

Science.gov (United States)

Zhong, Xuan; Yan, Jun; Li, Yan-Chun; Kong, Bo; Lu, Hong-Bing; Liang, Yi-Zeng

2014-11-28

In this work, a novel strategy based on chromatographic fingerprints and some chemometric techniques is proposed for quantitative analysis of the formulated complex system. Here, the formulated complex system means a formulated type of complicated analytical system containing more than one kind of raw material under some concentration composition according to a certain formula. The strategy is elaborated by an example of quantitative determination of mixtures consist of three essential oils. Three key steps of the strategy are as follows: (1) remove baselines of the chromatograms; (2) align retention time; (3) conduct quantitative analysis using multivariate regression with entire chromatographic profiles. Through the determination of concentration compositions of nine mixtures arranged by uniform design, the feasibility of the proposed strategy is validated and the factors that influence the quantitative result are also discussed. This strategy is proved to be viable and the validation indicates that quantitative result obtained using this strategy mainly depends on the efficiency of the alignment method as well as chromatographic peak shape of the chromatograms. Previously, chromatographic fingerprints were only used for identification and/or recognition of some products. This work demonstrates that with the assistance of some effective chemometric techniques, chromatographic fingerprints are also potential and promising in solving quantitative problems of complex analytical systems. Copyright © 2014 Elsevier B.V. All rights reserved.

1. Quantitative analysis of Glycyrrhizic acid from a polyherbal preparation using liquid chromatographic technique

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Amit K De

2012-01-01

Full Text Available Glycyrrhizic acid has been used in Indian traditional medicine for ages. It is obtained from the root extract of Glycyrrhizaglabra. There is seasonal variation of Glycyrrhizic acid content in the roots of the plant. So a proper method for quantification of the same is necessary from the polyherbal preparation available in the market. A simple, rapid, sensitive and specific reverse phase high performance liquid chromatographic method have been developed for the quantitative estimation of glycyrrhizic acid from polyherbal preparation containing aqueous root extract of Glycyrrhizaglabra using a photodiode array detector. The identity confirmation was carried out using mass spectrometry. Baseline resolution of the glycyrrhizic acid peak was achieved on a reverse phase C18 column (125 mm × 4.0 mm, 5 μ using an isocratic mobile phase consisting of 5.3 mM phosphate buffer and acetonitrile in the ratio 65:35 v/v. Chromatograms were monitored at 252 nm.5.3 mM phosphate buffer was replaced with 0.5mM ammonium acetate buffer in the mobile phase when MS detector was used. The method was found to be linear in the concentration range of 12.4 to124 μg/ml with a correlation co-efficient of 0.999. The limit of detection and the limit of quantitation were 3.08 μg/ml and 10.27 μg/ml respectively. The average recovery from three spike levels was 99.93 ± 0.26%. Identity confirmation of the chromatographic peak was achieved by electrospray ionization mass spectrometry and similar molecular ion peak was obtained for both sample and standard. The developed method is suitable for the routine analysis, stability testing and assay of glycyrrhizic acid from polyherbal preparations containing aqueous extracts of Glycyrrhizaglabra.

2. Gas Chromatographic Determination of Methyl Salicylate in Rubbing Alcohol: An Experiment Employing Standard Addition.

Science.gov (United States)

Van Atta, Robert E.; Van Atta, R. Lewis

1980-01-01

Provides a gas chromatography experiment that exercises the quantitative technique of standard addition to the analysis for a minor component, methyl salicylate, in a commercial product, "wintergreen rubbing alcohol." (CS)

3. Current applications of miniaturized chromatographic and electrophoretic techniques in drug analysis.

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Aturki, Zeineb; Rocco, Anna; Rocchi, Silvia; Fanali, Salvatore

2014-12-01

In the last decade, miniaturized separation techniques have become greatly popular in pharmaceutical analysis. Miniaturized separation methods are increasingly utilized in all processes of drug discovery as well as quality control of pharmaceutical preparation. The great advantages presented by the analytical miniaturized techniques, including high separation efficiency and resolution, rapid analysis and minimal consumption of reagents and samples, make them an attractive alternative to the conventional chromatographic methods for drug analysis. The purpose of this review is to give a general overview of the applicability of capillary electrophoresis (CE), capillary electrochromatography (CEC) and micro/capillary/nano-liquid chromatography (micro-LC/CLC/nano-LC) for the analysis of pharmaceutical formulations, active pharmaceutical ingredients (API), drug impurity testing, chiral drug separation, determination of drugs and metabolites in biological fluids. The results concerning the use of CEC, micro-LC, CLC, and nano-LC in the period 2009-2013, while for CE, those from 2012 up to the review draft are here summarized and some specific examples are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

4. Quantitative Analysis of Resorcinol from Marketed Hair Tonic Using Liquid Chromatographic Technique.

Science.gov (United States)

2014-01-01

Quantitative estimation of resorcinol from marketed pharmaceutical formulation has been reported in this study. Resorcinol as a pharmaceutical ingredient has a broad spectrum of application but its application is limited due to its toxic side effects. Method for the accurate estimation of resorcinol is therefore essential. In the current study we have developed a chromatographic technique for its estimation from a marketed hair tonic meant for the treatment of several dermatological diseases of the scalp. A stainless steel column 25 cm in length and 4 mm internal diameter packed with octadecylsilane (5 µm) was used for this purpose. The mobile phase was a mixture of phosphate buffer of pH 2.8 and acetonitrile. The flow rate was 0.6 mL·min(-1) and the detection wavelength was 280 nm. The method was found to be linear between concentration range 10.28 µg·mL(-1) to 71.96 µg·mL(-1) with r (2) value 0.999. The accuracy of the method and the intraday and interday precession study presents the applicability of the method for the estimation of resorcinol from any pharmaceutical and cosmetic product containing resorcinol.

5. Integrated Analysis of the Wood Oil from Xanthocyparis vietnamensis Farjon & Hiep. by Chromatographic and Spectroscopic Techniques.

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Bazzali, Ophélie; Thai, Tran Huy; Hoi, Tran Minh; Khang, Nguyen Sinh; Hien, Nguyen Thi; Casanova, Joseph; Bighelli, Ange; Tomi, Félix

2016-06-27

In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC) and spectroscopic (GC-MS, (13)C-NMR) techniques. Forty components that accounted for 87.9% of the oil composition have been identified. The composition is dominated by nootkatene (20.7%), 11,12,13-tri-nor-eremophil-1(10)-en-7-one (17.2%), γ-eudesmol (5.1%), nootkatone (4.7%), valencene (3.5%) and 13-nor-eremophil-1(10)-en-11-one (2.6%). The structure of two new compounds-10-epi-nor-γ-eudesmen-11-one and 12-hydroxy-isodihydroagarofuran-has been elucidated, while 11,12,13-tri-nor-eremophil-1(10)-en-7-ol is reported as a natural product for the first time. The composition of X. vietnamensis wood oil varied drastically from those of leaf oils, dominated by hedycaryol (34.4%), phyllocladene (37.8%) or by pimara-6(14)-15-diene (19.4%).

6. Integrated Analysis of the Wood Oil from Xanthocyparis vietnamensis Farjon & Hiep. by Chromatographic and Spectroscopic Techniques

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Ophélie Bazzali

2016-06-01

Full Text Available In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC and spectroscopic (GC-MS, 13C-NMR techniques. Forty components that accounted for 87.9% of the oil composition have been identified. The composition is dominated by nootkatene (20.7%, 11,12,13-tri-nor-eremophil-1(10-en-7-one (17.2%, γ-eudesmol (5.1%, nootkatone (4.7%, valencene (3.5% and 13-nor-eremophil-1(10-en-11-one (2.6%. The structure of two new compounds—10-epi-nor-γ-eudesmen-11-one and 12-hydroxy-isodihydroagarofuran—has been elucidated, while 11,12,13-tri-nor-eremophil-1(10-en-7-ol is reported as a natural product for the first time. The composition of X. vietnamensis wood oil varied drastically from those of leaf oils, dominated by hedycaryol (34.4%, phyllocladene (37.8% or by pimara-6(14-15-diene (19.4%.

7. Impurity analysis in EC-99mTC radiotracer using chromatographic techniques

International Nuclear Information System (INIS)

Almeida, E.V.; Fukumori, N.T.O.; Mengatti, J.; Silva, C.P.G.; Matsuda, M.M.N.

2008-01-01

The objective of this study was to develop two chromatographic methods of impurity analysis in radiotracer 99m Tc-EC: the Thin Layer Chromatography (TLC) and the High Performance Liquid Chromatography Reversed Phase (HPLC-RP)

8. Exploring Blueberry Aroma Complexity by Chromatographic and Direct-Injection Spectrometric Techniques

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Brian Farneti

2017-04-01

pull of VOCs, for the most aldehydes, alcohols, terpenoids, and esters that can be used as putative biomarkers to rapidly evaluate the blueberry aroma variations related to ripening and/or senescence as well as to genetic background differences. Moreover, the obtained results demonstrated the complementarity between chromatographic and direct-injection mass spectrometric techniques to study the blueberry aroma.

9. Exploring Blueberry Aroma Complexity by Chromatographic and Direct-Injection Spectrometric Techniques

Science.gov (United States)

Farneti, Brian; Khomenko, Iuliia; Grisenti, Marcella; Ajelli, Matteo; Betta, Emanuela; Algarra, Alberto Alarcon; Cappellin, Luca; Aprea, Eugenio; Gasperi, Flavia; Biasioli, Franco; Giongo, Lara

2017-01-01

, for the most aldehydes, alcohols, terpenoids, and esters that can be used as putative biomarkers to rapidly evaluate the blueberry aroma variations related to ripening and/or senescence as well as to genetic background differences. Moreover, the obtained results demonstrated the complementarity between chromatographic and direct-injection mass spectrometric techniques to study the blueberry aroma. PMID:28491071

10. Phytochemical screening and thin layer chromatographic profile of ...

African Journals Online (AJOL)

The present study investigates the phytochemicals and thin layer chromatographic profile of. Nauclea diderrichii (Rubiaceae) leaf extracts. Phytochemical in the hexane, ethyl acetate and methanol extracts were determined using standard chemical tests. Thin layer chromatographic techniques were carried out using various ...

11. Chromatographic separations of stereoisomers

Energy Technology Data Exchange (ETDEWEB)

Souter, R.W.

1985-01-01

This text covers both diastereomers and enantiomers; describes techniques for GC, HPLC, and other chromatographic methods; and tabulates results of various applications by both techniques and compound class. It provides current knowledge about separation mechanisms and interactions of asymmetric molecules, as well as experimental and commercial materials such as columns, instruments, and derivatization reagents. The contents also include stereoisomer separations by gas chromatography. Stereoisomer separations by high-performance liquid chromatography. Stereoisomer separations by other chromatographic techniques.

12. Gas Chromatographic Mass Spectrometric Determination of Myo-inositol in Humans Utilizing a Deuterated Internal Standard

DEFF Research Database (Denmark)

Andersen, Jan Rud; Larsen, Elfinn; Harbo, Helge

1982-01-01

The isotopic dilution technique was used for determining the content of myo-inositol in human urine, plasma and haemolysed erythrocyte samples. A deuterated myo-inositol, synthesized from inosose-2 by base-catalysed exchange of hydrogens by deuterium, followed by reduction of the inosose with 2H2...

13. Element selective detection of molecular species applying chromatographic techniques and diode laser atomic absorption spectrometry.

Science.gov (United States)

Kunze, K; Zybin, A; Koch, J; Franzke, J; Miclea, M; Niemax, K

2004-12-01

Tunable diode laser atomic absorption spectroscopy (DLAAS) combined with separation techniques and atomization in plasmas and flames is presented as a powerful method for analysis of molecular species. The analytical figures of merit of the technique are demonstrated by the measurement of Cr(VI) and Mn compounds, as well as molecular species including halogen atoms, hydrogen, carbon and sulfur.

14. The extraction and chromatographic determination of the essentials oils from Ocimum basilicum L. by different techniques

Science.gov (United States)

Loredana Soran, Maria; Codruta Cobzac, Simona; Varodi, Codruta; Lung, Ildiko; Surducan, Emanoil; Surducan, Vasile

2009-08-01

Three different techniques (maceration, sonication and extraction in microwave field) were used for extraction of essential oils from Ocimum basilicum L. The extracts were analyzed by TLC/HPTLC technique and the fingerprint informations were obtained. The GC-FID was used to characterized the extraction efficiency and for identify the terpenic bioactive compounds. The most efficient extraction technique was maceration followed by microwave and ultrasound. The best extraction solvent system was ethyl ether + ethanol (1:1, v/v). The main compounds identified in Ocimum basilicum L. extracts were: α and β-pinene (mixture), limonene, citronellol, and geraniol.

15. The extraction and chromatographic determination of the essentials oils from Ocimum basilicum L. by different techniques

Energy Technology Data Exchange (ETDEWEB)

Soran, Maria Loredana; Varodi, Codruta; Lung, Ildiko; Surducan, Emanoil; Surducan, Vasile [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Cobzac, Simona Codruta, E-mail: loredana.soran@itim-cj.r [Babes-Bolyai University, Faculty of Chemistry and Chemical Engineering, 11 Arany Janos, 400028 Cluj-Napoca (Romania)

2009-08-01

Three different techniques (maceration, sonication and extraction in microwave field) were used for extraction of essential oils from Ocimum basilicum L. The extracts were analyzed by TLC/HPTLC technique and the fingerprint informations were obtained. The GC-FID was used to characterized the extraction efficiency and for identify the terpenic bioactive compounds. The most efficient extraction technique was maceration followed by microwave and ultrasound. The best extraction solvent system was ethyl ether + ethanol (1:1, v/v). The main compounds identified in Ocimum basilicum L. extracts were: {alpha} and {beta}-pinene (mixture), limonene, citronellol, and geraniol.

16. Insights into Adsorption of Chlorobenzene in High Silica MFI and FAU Zeolites Gained from Chromatographic and Diffractometric Techniques

Directory of Open Access Journals (Sweden)

Luisa Pasti

2018-02-01

Full Text Available In this work, the capability of two commercial high silica zeolites (HSZs, namely ZSM-5 and Y, for the removal of chlorobenzene (CB from water was investigated by combining chromatographic and diffractometric techniques. The adsorption isotherms and kinetics of CB on ZSM-5 and Y zeolites were determined from batch tests. The adsorption kinetics were very fast; the time to reach equilibrium was less than 10 min. The equilibrium data of CB on the two HSZs showed dissimilarities that are particularly evident in the adsorption data concerning the low concentration range, where Y zeolite is characterized by low adsorption. On the contrary, at higher solution concentrations the adsorption capacity of Y is higher than that of ZSM-5. The crystalline structures of Y and ZSM-5 saturated with CB were investigated by X-ray diffraction (XRD techniques. Rietveld refinement analyses of XRD data allowed for quantitative probing of the structural modifications of both zeolites after CB adsorption and provided insight into the preferred zeolite adsorption sites in both microporous materials. The refined framework–extraframework bond distances confirm that interactions between the selected organic contaminant and hydrophobic zeolites are mediated via co-adsorbed H2O. The occurrence of H2O–CB–framework oxygen oligomers explains variations in both the unit cell parameters and the shape of the channels, clearly confirming that water plays a very relevant role in controlling the diffusion and adsorption processes in hydrophobic zeolites.

17. Chromatographic Fingerprint Analysis of Marrubiin in Marrubium vulgare L. via HPTLC Technique

OpenAIRE

2016-01-01

Purpose: In the present study we aimed to quantify marrubiin, as the major active compound, in the aerial parts of Marrubium vulgare from Iran using a HPTLC-densitometry technique. Methods: Quantitative determination of marrubiin in M. vulgare methanol extract was performed by HPTLC analysis via a fully automated TLC scanner. Later on, the in vitro antioxidant activity of the M. vulgare methanol extract was determined using 1,1-diphenyl-2-picryl-hydrazil (DPPH) free radic...

18. Sample preparation for large-scale bioanalytical studies based on liquid chromatographic techniques.

Science.gov (United States)

Medvedovici, Andrei; Bacalum, Elena; David, Victor

2018-01-01

Quality of the analytical data obtained for large-scale and long term bioanalytical studies based on liquid chromatography depends on a number of experimental factors including the choice of sample preparation method. This review discusses this tedious part of bioanalytical studies, applied to large-scale samples and using liquid chromatography coupled with different detector types as core analytical technique. The main sample preparation methods included in this paper are protein precipitation, liquid-liquid extraction, solid-phase extraction, derivatization and their versions. They are discussed by analytical performances, fields of applications, advantages and disadvantages. The cited literature covers mainly the analytical achievements during the last decade, although several previous papers became more valuable in time and they are included in this review. Copyright © 2017 John Wiley & Sons, Ltd.

19. Development of a simple technique for the coating of monolithic silica with pristine boron nitride nanotubes (BNNTs): HPLC chromatographic applications.

Science.gov (United States)

Guillaume, Yves Claude; André, Claire

2017-03-01

In this paper, a novel and very simple homogeneous coating of a monolithic silica HPLC support using pristine boron nitride nanotubes (BNNTs) was d0.escribed. The chromatographic support was coated with BNNTs in a non covalent way to preserve the nanotube structure. A solution of BNNTs dispersed in dimethylacetamide (DMAc) was pumped through the column at a flow-rate of 0.3mL/min for 24h at room temperature. Strong interaction between amino groups and the BNNT surfaces induces the adsorption of the BNNTs on the silica, while the stable solvation in DMAc hampers further adsorption of the tubes. The excellent stability of the non covalent BNNT-coating on the monolithic silica in view of application for HPLC was also demonstrated. It was shown that this novel stationary phase was efficient for the HPLC isocratic or gradient mode separation of molecules of different structure such as phenol derivatives, alkylbenzene or doping agents (steroids). As well, this simple technique of BNNT immobilization offers new perspectives for the BNNT-coating on the surfaces of a wide range of solid substrates. Copyright © 2016 Elsevier B.V. All rights reserved.

20. Chromatographic Fingerprint Analysis of Marrubiin in Marrubium vulgare L. via HPTLC Technique.

Science.gov (United States)

2016-03-01

In the present study we aimed to quantify marrubiin, as the major active compound, in the aerial parts of Marrubium vulgare from Iran using a HPTLC-densitometry technique. Quantitative determination of marrubiin in M. vulgare methanol extract was performed by HPTLC analysis via a fully automated TLC scanner. Later on, the in vitro antioxidant activity of the M. vulgare methanol extract was determined using 1,1-diphenyl-2-picryl-hydrazil (DPPH) free radical scavenging assay. Furthermore, total phenolics and flavonoids contents of the methanol extract were quantified, spectrophotometrically. The amount of marrubiin was calculated as 156 mg/g of M. vulgare extract. The antioxidant assay revealed a strong radical scavenging activity for the M. vulgare methanol extract with RC50 value of 8.24μg/mL. Total phenolics and flavonoids contents for M. vulgare were determined as 60.4 mg gallic acid equivalent and 12.05 mg quercetin equivalent per each gram of the extract, correspondingly. The presented fingerprint of marrubiin in M. vulgare extract developed by HPTLC densitometry afforded a detailed chemical profile, which might be useful in the identification as well as quality evaluation of herbal medications based on M. vulgare. Besides, the considerable antioxidant activity of M. vulgare was associated with the presence of marrubiin along with phenolics and flavonoids exerting a synergistic effect.

1. Four new degradation products of doxorubicin: An application of forced degradation study and hyphenated chromatographic techniques

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Dheeraj Kaushik

2015-10-01

Full Text Available Forced degradation study on doxorubicin (DOX was carried out under hydrolytic condition in acidic, alkaline and neutral media at varied temperatures, as well as under peroxide, thermal and photolytic conditions in accordance with International Conference on Harmonization (ICH guidelines Q1(R2. It was found extremely unstable to alkaline hydrolysis even at room temperature, unstable to acid hydrolysis at 80Â Â°C, and to oxidation at room temperature. It degraded to four products (O-IâO-IV in oxidative condition, and to single product (A-I in acid hydrolytic condition. These products were resolved on a C8 (150Â mmÃ4.6Â mm, 5Â Âµm column with isocratic elution using mobile phase consisting of HCOONH4 (10Â mM, pH 2.5, acetonitrile and methanol (65:15:20, v/v/v. Liquid chromatographyâphotodiode array (LCâPDA technique was used to ascertain the purity of the products noted in LCâUV chromatogram. For their characterization, a six stage mass fragmentation (MS6 pattern of DOX was outlined through mass spectral studies in positive mode of electrospray ionization (+ESI as well as through accurate mass spectral data of DOX and the products generated through liquid chromatographyâtime of flight mass spectrometry (LCâMSâTOF on degraded drug solutions. Based on it, O-IâO-IV were characterized as 3-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 1-hydroxy-9-desacetyldoxorubicin-9-hydroperoxide, 9-desacetyldoxorubicin-9-hydroperoxide and 9-desacetyldoxorubicin, respectively, whereas A-I was characterized as deglucosaminyl doxorubicin. While A-I was found to be a pharmacopoeial impurity, all oxidative products were found to be new degradation impurities. The mechanisms and pathways of degradation of doxorubicin were outlined and discussed. Keywords: Doxorubicin, TOF, Forced degradation, Liquid chromatography, Degradation product, Mass fragmentation pattern

2. ELISA technique standardization for strongyloidiasis diagnosis

International Nuclear Information System (INIS)

Huapaya, P.; Espinoza, I.; Huiza, A.; Universidad Nacional Mayor de San Marcos, Lima; Sevilla, C.

2002-01-01

To standardize ELISA technique for human Strongyloides stercoralis infection diagnosis a crude antigen was prepared using filariform larvae obtained from positive stool samples cultured with charcoal. Harvested larvae were crushed by sonication and washed by centrifugation in order to obtain protein extracts to be used as antigen. Final protein concentration was 600 μg/mL. Several kinds of ELISA plates were tested and antigen concentration, sera dilution, conjugate dilution and cut off were determined to identify infection. Sera from patients with both hyper-infection syndrome and intestinal infection demonstrated by parasitological examination were positive controls and sera from people living in non-endemic areas with no infection demonstrated by parasitological examination were negative controls. Best values were 5 μg/mL for antigen, 1/64 for sera, 1/1000 for conjugate; optical density values for positive samples were 1,2746 (1,1065 - 1,4206, DS = 0,3284) and for negative samples 0,4457 (0,3324 - 0,5538, DS = 0,2230). Twenty sera samples from positive subjects and one hundred from negative subjects were examined, obtaining 90% sensitivity and 88% specificity. The results show this technique could be useful as strongyloidiasis screening test in population studies

3. Determination of the analytical performance of a headspace capillary gas chromatographic technique and karl Fischer coulometric titration by system calibration using oil samples containing known amounts of moisture.

Science.gov (United States)

Jalbert, J; Gilbert, R; Tétreault, P

1999-08-01

Over the past few years, concerns have been raised in the literature about the accuracy of the Karl Fischer (KF) method for assessing moisture in transformer mineral oils. To better understand this issue, the performance of a static headspace capillary gas chromatographic (HS-CGC) technique was compared to that of KF coulometric titration by analyzing moisture in samples containing known amounts of water and various samples obtained from the National Institute of Standards and Technology (NIST). Two modes of adding samples into the KF vessel were used:  direct injection and indirect injection via an azeotropic distillation of the moisture with toluene. Under the conditions used for direct injection, the oil matrix was totally dissolved in the anolyte, which allowed the moisture to be titrated in a single-phase solution rather than in a suspension. The results have shown that when HS-CGC and combined azeotropic distillation/KF titration are calibrated with moisture-in-oil standards, a linear relation is observed over 0-60 ppm H(2)O with a correlation coefficient better than 0.9994 (95% confidence), with the regression line crossing through zero. A similar relation can also be observed when calibration is achieved by direct KF addition of standards prepared with octanol-1, but in this case an intercept of 4-5 ppm is noted. The amount of moisture determined by curve interpolation in NIST reference materials by the three calibrated systems ranges from 13.0 to 14.8 ppm for RM 8506 and 42.5 to 46.4 ppm for RM 8507, and in any case, the results were as high as those reported in the literature with volumetric KF titration. However, titration of various dehydrated oil and solvent samples showed that direct KF titration is affected by a small bias when samples contain very little moisture. The source of error after correction for the large sample volume used for the determination (8 mL) is about 6 ppm for Voltesso naphthenic oil and 4 ppm for toluene, revealing a matrix

4. CHROMATOGRAPHIC SEPARATION AND SPECTRO ...

African Journals Online (AJOL)

The spectro-analytical techniques used for characterization included energy dispersive X-ray fluorescence (EDXRF), X-ray diffractometry (XRD), Optical microscopy, infrared (IR) and UV-VIS spectroscopy. Four different fractions having colours yellow, grey, orange and purple were obtained from the chromatographic ...

5. Trans fat labeling and levels in U.S. foods: assessment of gas chromatographic and infrared spectroscopic techniques for regulatory compliance.

Science.gov (United States)

Mossoba, Magdi M; Moss, Julie; Kramer, John K G

2009-01-01

Trans fatty acids are found in a variety of foods like dairy and meat products, but the major dietary sources are products that contain commercially hydrogenated fats. There has been a renewed need for accurate analytical methods for the quantitation of total trans fat since mandatory requirements to declare the amount of trans fat present in food products and dietary supplements were issued in many countries. Official capillary GC and IR methodologies are the two most common validated methods used to identify and quantify trans fatty acids for regulatory compliance. The present article provides a comprehensive discussion of the GC and IR techniques, including the latest attenuated total reflection (ATR)-FTIR methodology called the negative second derivative ATR-FTIR procedure, which is currently being validated in an international collaborative study. The identification and quantitation of trans fatty acid isomers by GC is reviewed and an alternative GC method is proposed using two temperature programs and combining their results; this proposed method deals more effectively with the resolution of large numbers of geometric and positional monoene, diene, and triene fatty acid isomers present in ruminant fats. In addition, the different methylation procedures that affect quantitative conversion to fatty acid methyl esters are reviewed. There is also a lack of commercial chromatographic standards for many trans fatty acid isomers. This review points to potential sources of interferences in the FTIR determination that may lead to inaccurate results, particularly at low trans levels. The presence of high levels of saturated fats may lead to interferences in the FTIR spectra observed for trans triacylglycerols (TAGs). TAGs require no derivatization, but have to be melted prior to IR measurement. While GC is currently the method of choice, ATR-FTIR spectroscopy is a viable, rapid alternative, and a complementary method to GC for a more rapid determination of total trans

6. Study of the photodegradation of 2-bromophenol under UV and sunlight by spectroscopic, chromatographic and chemometric techniques.

Science.gov (United States)

Jayaraman, Anusha; Mas, Sílvia; Tauler, Romà; de Juan, Anna

2012-12-01

7. Determination and Standardization of a Method for Caffeine in the Roasting Process Chromatographic High Performance Liquid (Hplc

Directory of Open Access Journals (Sweden)

Jesús A. Rubiano

2012-06-01

Full Text Available The work done in the organization. COFFEE COLONIAL.SAS was to evaluate, analyze and verify key information for the identification and standardization of a method for caffeine in coffee roastingprocess by the technique of chromatography high performance liquid (HPLC.Assays were performed at different roasting process to get the right conditions for the samples, supported by transport phenomena such as, energy, fluids and heat, in addition to following the guidelinesof the Standard ISO 2859-1 Colombian NTC.To obtain a standard curve, leading to interpolate coffee samples, prepare a solution with Caffeine (Sigma-Aldrich, Analytical Reagent and Milli-Q water (Millipore Merck 40 ppm, to obtain a solution pattern, from the solution of caffeine more solutions were prepared by 5 micrograms per milliliter caffeine.To determine the most suitable mobile phase, it began testing different samples of caffeine of coffee with the same water-acetonitrile mobile phase in different proportions, once all the necessary tests and according to the results obtained, the mobile phase allow better separation and interaction with the stationary phase was composed of water-acetonitrile mobile phase in 20:80 ratio.After obtaining the calibration curve and the more appropriate mobile phase, where injections were made different chromatograms were obtained with bases and defined peaks, which are defined by giving a correlation coefficient of linearity close to one, after which the next step was to find the area under the curve to define the caffeine concentration of the samples and thus being able to express in percentage.

8. Ambient formaldehyde measurements made at a remote marine boundary layer site during the NAMBLEX campaign – a comparison of data from chromatographic and modified Hantzsch techniques

Directory of Open Access Journals (Sweden)

T. J. Still

2006-01-01

Full Text Available Ambient formaldehyde concentrations are reported from the North Atlantic Marine Boundary Layer Experiment (NAMBLEX campaign at Mace Head on the west coast of Eire during August 2002. The results from two techniques, using direct determination via gas chromatography and the Hantzsch technique, show similar trends but a significant off set in concentrations. For westerly air flows characteristic of the marine boundary layer, formaldehyde concentrations from the gas chromatographic and Hantzsch technique ranged from 0.78–1.15 ppb and 0.13–0.43 ppb, respectively. Possible reasons for the discrepancy have been investigated and are discussed, however, no satisfactory explanation has yet been found. In a subsequent laboratory intercomparison the two techniques were in good agreement. The observed concentrations have been compared with previous formaldehyde measurements in the North Atlantic marine boundary layer and with other measurements from the NAMBLEX campaign. The measurements from the Hantzsch technique and the GC results lie at the lower and upper ends respectively of previous measurements. In contrast to some previous measurements, both techniques show distinct diurnal profiles with day maxima and with an amplitude of approximately 0.15 ppb. Strong correlations were observed with ethanal concentrations measured during NAMBLEX and the ratio of ethanal to formaldehyde determined by the gas chromatographic technique is in good agreement with previous measurements. Some simple box modelling has been undertaken to investigate possible sources of formaldehyde. Such models are not able to predict absolute formaldehyde concentrations as they do not include transport processes, but the results show that oxygenated VOCs such as ethanal and methanol are very significant sources of formaldehyde in the air masses reaching Mace Head.

9. Video Coding Technique using MPEG Compression Standards ...

African Journals Online (AJOL)

Some application areas of video compression focused on the problem of optimizing storage space and transmission bandwidth (BW). The two dimensional discrete cosine transform (2-D DCT) is an integral part of video and image compression, which is used in Moving Picture Expert Group (MPEG) encoding standards.

10. [Ideas and methods of two-dimensional zebrafish model combined with chromatographic techniques in high-throughput screening of active anti-osteoporosis components of traditional Chinese medicines].

Science.gov (United States)

Wei, Ying-Jie; Jing, Li-Jun; Zhan, Yang; Sun, E; Jia, Xiao-Bin

2014-05-01

To break through the restrictions of the evaluation model and the quantity of compounds by using the two-dimensional zebrafish model combined with chromatographic techniques, and establish a new method for the high-throughput screening of active anti-osteoporosis components. According to the research group-related studies and relevant foreign literatures, on the basis of the fact that the zebrafish osteoporosis model could efficiently evaluate the activity, the zebrafish metabolism model could efficiently enrich metabolites and the chromatographic techniques could efficiently separate and analyze components of traditional Chinese medicines, we proposed that the inherent combination of the three methods is expected to efficiently decode in vivo and in vitro efficacious anti-osteoporosis materials of traditional Chinese medicines. The method makes it simple and efficient in the enrichment, separation and analysis on components of traditional Chinese medicines, particularly micro-components and metabolites and the screening anti-osteoporosis activity, fully reflects that efficacious materials of traditional Chinese medicines contain original components and metabolites, with characteristic of "multi-components, multi-targets and integral effect", which provides new ideas and methods for the early and rapid discovery of active anti-osteoporosis components of traditional Chinese medicines.

11. A modified high-performance liquid chromatographic method for the analysis of pantoprazole sodium in pharmaceutical dosage forms using lansoprazole as internal standard

Directory of Open Access Journals (Sweden)

Safwan Ashour

2016-09-01

Full Text Available A Simple and rapid reversed-phase high-performance liquid chromatographic method for the direct determination of pantoprazole in pharmaceutical dosage forms was developed and validated. Lansoprazole was used as internal standard. The chromatographic separation of pantoprazole and lansoprazole was achieved on a Nucleodur C8 column (250 × 4.6 mm i.d., 5 μm particle size using the photodiode array detector at 280 nm. The optimized mobile phase was consisted of a mixture of 0.1 M ammonium acetate solution and methanol (42:58, v/v, pumped at a flow rate 1.0 mL min−1. The retention times for pantoprazole and lansoprazole were 8.10 and 11.15 min, respectively. Linearity range was 3.06–1243.0 μg mL−1 with limit of detection value of 0.78 μg mL−1. The precision of the method was demonstrated using intra- and inter-day assay RSD% values which were less than 2.07%, while the recovery was 99.07–103.95%. No interference from any components of pharmaceutical dosage forms or degradation products was observed. According to the validation results, the proposed method was found to be specific, accurate, precise and could be applied to the quantitative analysis of pantoprazole in tablets.

12. Contribution to the standardization of the chromatographic conditions for the lipophilicity assessment of neutral and basic drugs

Energy Technology Data Exchange (ETDEWEB)

Giaginis, Costas [Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771 (Greece); Department of Forensic Medicine and Toxicology, Medical School, University of Athens, 75 Mikras Asias Street, Athens 11527 (Greece); Theocharis, Stamatios [Department of Forensic Medicine and Toxicology, Medical School, University of Athens, 75 Mikras Asias Street, Athens 11527 (Greece); Tsantili-Kakoulidou, Anna [Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771 (Greece)]. E-mail: tsantili@pharm.uoa.gr

2006-07-28

The chromatographic conditions aiming to a better simulation of n-octanol-water partitioning using a base deactivated silica (BDS) column as stationary phase were investigated for structurally diverse basic and neutral drugs. Extrapolated retention factors log k{sub w}, determined using different methanol fractions as organic modifier, were considered as lipophilicity indices. The effect of n-decylamine and n-octanol as mobile phase additives was examined and the appropriateness of the final retention outcome to reproduce lipophilicity data was evaluated. Moreover, the influence of n-octanol on the linearity of the log k/methanol fraction relationship and on the uniformity of the retention mechanism was investigated. 1:1 correlation between log k{sub w} values and the logarithm of the distribution coefficient (log D) was established for basic drugs in presence of both n-decylamine and n-octanol as mobile phase additives. However, for neutral drugs n-decylamine proved to be a sufficient and more important factor than n-octanol.

13. A technique for rapid source apportionment applied to ambient organic aerosol measurements from a thermal desorption aerosol gas chromatograph (TAG

Directory of Open Access Journals (Sweden)

Y. Zhang

2016-11-01

Full Text Available We present a rapid method for apportioning the sources of atmospheric organic aerosol composition measured by gas chromatography–mass spectrometry methods. Here, we specifically apply this new analysis method to data acquired on a thermal desorption aerosol gas chromatograph (TAG system. Gas chromatograms are divided by retention time into evenly spaced bins, within which the mass spectra are summed. A previous chromatogram binning method was introduced for the purpose of chromatogram structure deconvolution (e.g., major compound classes (Zhang et al., 2014. Here we extend the method development for the specific purpose of determining aerosol samples' sources. Chromatogram bins are arranged into an input data matrix for positive matrix factorization (PMF, where the sample number is the row dimension and the mass-spectra-resolved eluting time intervals (bins are the column dimension. Then two-dimensional PMF can effectively do three-dimensional factorization on the three-dimensional TAG mass spectra data. The retention time shift of the chromatogram is corrected by applying the median values of the different peaks' shifts. Bin width affects chemical resolution but does not affect PMF retrieval of the sources' time variations for low-factor solutions. A bin width smaller than the maximum retention shift among all samples requires retention time shift correction. A six-factor PMF comparison among aerosol mass spectrometry (AMS, TAG binning, and conventional TAG compound integration methods shows that the TAG binning method performs similarly to the integration method. However, the new binning method incorporates the entirety of the data set and requires significantly less pre-processing of the data than conventional single compound identification and integration. In addition, while a fraction of the most oxygenated aerosol does not elute through an underivatized TAG analysis, the TAG binning method does have the ability to achieve molecular level

14. Secondary metabolites isolation in natural products chemistry: comparison of two semipreparative chromatographic techniques (high pressure liquid chromatography and high performance thin-layer chromatography).

Science.gov (United States)

Do, Thi Kieu Tiên; Hadji-Minaglou, Francis; Antoniotti, Sylvain; Fernandez, Xavier

2014-01-17

Chemical investigations on secondary metabolites in natural products chemistry require efficient isolation techniques for characterization purpose as well as for the evaluation of their biological properties. In the case of phytochemical studies, the performance of the techniques is critical (resolution and yield) since the products generally present a narrow range of polarity and physicochemical properties. Several techniques are currently available, but HPLC (preparative and semipreparative) is the most widely used. To compare the performance of semipreparative HPLC and HPTLC for the isolation of secondary metabolites in different types of extracts, we have chosen carvone from spearmint essential oil (Mentha spicata L.), resveratrol from Fallopia multiflora (Thunb.) Haraldson, and rosmarinic acid from rosemary (Rosmarinus officinalis L.) extracts. The comparison was based on the chromatographic separation, the purity and quantity of isolated compounds, the solvent consumption, the duration and the cost of the isolation operations. The results showed that semipreparative HPTLC can in some case offer some advantages over conventional semipreparative HPLC. Copyright © 2013 Elsevier B.V. All rights reserved.

15. High-performance liquid chromatographic analysis of cyclosporin A in rat blood and liver using a commercially available internal standard.

Science.gov (United States)

Chimalakonda, Anjaneya P; Shah, Rakhi B; Mehvar, Reza

2002-05-25

All the available HPLC assays of cyclosporin A (CyA) use internal standards that are not commercially available. Our purpose was to develop an HPLC assay for measurements of CyA in rat blood and liver using a commercially available internal standard (I.S.). After the addition of tamoxifen (I.S.), blood (0.25 ml) or the liver homogenate (1 ml) samples were extracted into a mixture of ether:methanol (95:5). The residue after evaporation of the organic layer was dissolved in 200 microl of an injection solution and washed with 1 ml of hexane before analysis. The separation was achieved using an LC-1 column (70 degrees C) with a mobile phase of methanol-acetonitrile-0.01 M KH(2)PO(4) (50:25:25, v/v) and a flow-rate of 1 ml/min. Detection was at 205 nm. Cyclosporin A and I.S. eluted at 5 and 7 min, respectively, free from endogenous peaks. Linear relationships (r>0.98) were observed between the CyA:I.S. peak area ratios and the CyA concentrations within the range of 0.2-10 microg/ml for blood and 0.1-4 microg/ml for the liver homogenates. The intra- and inter-run C.V.s and errors for both the blood and liver samples were <15%. The extraction efficiency (n=5) was close to 100% for both CyA and I.S. in both blood and liver homogenates. The lower limit of quantitation of the assay was 0.2 or 0.1 microg/ml based on 250 microl of blood or 1 ml of liver homogenate, respectively. The assay was capable of measuring blood and liver concentrations of CyA in a rat injected intravenously with a single 5-mg/kg dose of the drug.

16. Hyphenated chromatographic techniques for the rapid screening and identification of antioxidants in methanolic extracts of pharmaceutically used plants .

NARCIS (Netherlands)

Exarchou, V.; Fiamegos, Y.C.; Beek, van T.A.; Nanos, C.G.; Vervoort, J.J.M.

2006-01-01

Phytochemical analysis is an important scientific research area, which normally relies on a number of rather laborious and time-consuming techniques for compound identification. Isolation of the ingredients of plant extracts in adequate quantities for spectral and biological analysis was the basis

17. Gas chromatographic sulphur speciation in heavy crude oil using a modified standard D5623 method and microfluidic Deans switching.

Science.gov (United States)

Heshka, Nicole E; Choy, Joanne M; Chen, Jinwen

2017-12-29

A modification to American Society for Testing and Materials (ASTM) method D5623 is proposed to enable successful and repeatable analysis of heavy crude oil samples. A two-dimensional gas chromatography configuration was implemented, with separation of sulphur compounds occurring on two columns. A Deans switch is used to enable heart-cutting of volatile sulphur compounds onto a DB-Sulfur stationary phase, and separation occurs concurrently with the backflushing of the primary column. The use of a sulphur-selective detector increases selectivity, and 22 volatile sulphur species are quantified in less than 15min, which is almost half the time of the original ASTM method. Samples ranging from light distillation cuts to whole crudes (boiling from 100°C to >750°C) were analyzed with minimal sample preparation. The calculated limit of detection was 0.7mg/kg, repeatability was 3% relative standard deviation (RSD), and a linear range of 1-250mg/kg was obtained, with an R 2 value of 0.994 or better, depending on the compound. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

18. Detection of clenbuterol at trace levels in doping analysis using different gas chromatographic-mass spectrometric techniques.

Science.gov (United States)

Yang, Sheng; Liu, Xin; Xing, Yanyi; Zhang, Dapeng; Wang, Shan; Wang, Xiaobing; Xu, Youxuan; Wu, Moutian; He, Zhenwen; Zhao, Jian

2013-01-01

This study demonstrates the development of a gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS-MS) assay to detect clenbuterol in human urine and the comparison of this method with GC-MS techniques and gas chromatography-high resolution mass spectrometry (GC-HRMS) techniques. Urine samples were hydrolyzed with β-glucuronidase, extracted with methyl tert-butyl ether and dried under nitrogen. The derivative reagent was N-methyl-N-(trimethylsilyl)-trifluoroacetamide with NH4I and was analyzed by GC-MS, GC-MS-MS and GC-HRMS. A validation study was conducted by GC-MS-MS. The analyses of clenbuterol using different mass spectrometric techniques were compared. The limit of detection (LOD) for clenbuterol in human urine was 2 ng/mL by GC-MS (selected ion monitoring mode: SIM mode), 0.06 ng/mL by GC-HRMS and 0.03 ng/mL by GC-MS-MS, respectively, while the LOD by GC-HRMS was 0.06. With GC-MS-MS, the intra-assay and inter-assay precisions were less than 15%, the recoveries were 86 to 112% and the linear range was 0.06 to 8.0 ng/mL. The GC-MS under SIM mode can be used as a screening tool to detect clenbuterol at trace levels in human urine. The GC-MS-MS and GC-HRMS methods can confirm clenbuterol when its concentration is below 2 ng/mL. The results demonstrate that the GC-MS-MS method is quite sensitive, specific and reliable for the detection of clenbuterol in doping analysis.

19. Standardization of P-33 by the TDCR efficiency calculation technique

CSIR Research Space (South Africa)

Simpson, BRS

2004-02-01

Full Text Available and Isotopes 60 (2004) 465?468 The standardization of 33P by the TDCR efficiency calculation technique B.R.S. Simpson*, W.M. Morris Radioactivity Standards Laboratory, CSIR?NML, 15 Lower Hope Road, Rosebank, Cape Town 7700, South Africa Abstract The activity... allowed). 2. Review of the TDCR efficiency calculation technique A LS source is viewed by a three-phototube detection system and the double-tube coincidence counting rate Nd and the triple-tube rate Nt are recorded simulta- neously. If N0 is the 33P...

20. [How to write an andrological paper: standardization, mechanics and techniques].

Science.gov (United States)

Huang, Yu-Feng; Lu, Jin-Chun

2010-12-01

Andrological research papers not only reflect the current status and academic level of andrology, but also constitute an important communication platform for researchers and clinicians engaged in this field and contribute significantly to the development of andrology. It would be made easier to write a high-quality andrological paper once the author observes the basic requirements of research papers, adheres to the use of standard scientific terminology, knows the special writing mechanics, and equips himself with some essential writing techniques. Based on the long experience of editorship, we present a detailed introduction of the standardization, mechanics and techniques of writing an andrological paper.

1. Chemical profiles of traditional preparations of four South American Passiflora species by chromatographic and capillary electrophoretic techniques

Directory of Open Access Journals (Sweden)

Geison Modesti Costa

Full Text Available ABSTRACT Several species of the genus Passiflora are distributed all over South America, and many of these species are used in popular medicine, mainly as sedatives and tranquilizers. This study analyzes the chemical profile of extracts of four Passiflora species used in folk medicine, focusing on the flavonoids, alkaloids and saponins. We employed simple and fast fingerprint analysis methods by high performance liquid chromatography, ultra performance liquid chromatography and capillary electrophoresis techniques. The analysis led to the detection and identification of C-glycosylflavonoids in all the plant extracts, these being the main constituents in P. tripartita var. mollissima and P. bogotensis. Saponins were observed only in P. alata and P. quadrangularis, while harmane alkaloids were not detected in any of the analyzed extracts in concentrations higher than 0.0187 ppm, the detection limit determined for the UPLC method.

2. Paediatric sutureless circumcision-an alternative to the standard technique.

LENUS (Irish Health Repository)

2012-01-31

INTRODUCTION: Circumcision is one of the most commonly performed surgical procedures in male children. A range of surgical techniques exist for this commonly performed procedure. The aim of this study is to assess the safety, functional outcome and cosmetic appearance of a sutureless circumcision technique. METHODS: Over a 9-year period, 502 consecutive primary sutureless circumcisions were performed by a single surgeon. All 502 cases were entered prospectively into a database including all relevant clinical details and a review was performed. The technique used to perform the sutureless circumcision is a modification of the standard sleeve technique with the use of a bipolar diathermy and the application of 2-octyl cyanoacrylate (2-OCA) to approximate the tissue edges. RESULTS: All boys in this study were pre-pubescent and the ages ranged from 6 months to 12 years (mean age 3.5 years). All patients had this procedure performed as a day case and under general anaesthetic. Complications included: haemorrhage (2.2%), haematoma (1.4%), wound infection (4%), allergic reaction (0.2%) and wound dehiscence (0.8%). Only 9 (1.8%) parents or patients were dissatisfied with the cosmetic appearance. CONCLUSION: The use of 2-OCA as a tissue adhesive for sutureless circumcisions is an alternative to the standard suture technique. The use of this tissue adhesive, 2-OCA, results in comparable complication rates to the standard circumcision technique and results in excellent post-operative cosmetic satisfaction.

3. Comparison of three chromatographic techniques for the detection of mitragynine and other indole and oxindole alkaloids in Mitragyna speciosa (kratom) plants.

Science.gov (United States)

Wang, Mei; Carrell, Emily J; Ali, Zulfiqar; Avula, Bharathi; Avonto, Cristina; Parcher, Jon F; Khan, Ikhlas A

2014-06-01

Leaves of the Southeast Asian plant Mitragyna speciosa are used to suppress pain and mitigate opioid withdrawal syndromes. The potential threat of abuse and ready availability of this uncontrolled psychoactive plant have led to the need for improved analytical techniques for the detection of the major active components, mitragynine and 7-hydroxymitragynine. Three independent chromatographic methods coupled to two detection systems, GC with MS, supercritical fluid chromatography with diode array detection, and HPLC with MS and diode array detection, were compared for the analysis of mitragynine and other indole and oxindole alkaloids in M. speciosa plants. The indole alkaloids included two sets of diastereoisomers: (i) paynantheine and 3-isopaynantheine and (ii) mitragynine, speciogynine, and speciociliatine. Two oxindole alkaloid diastereoisomers, corynoxine and corynoxine B, were also studied. The HPLC and supercritical fluid chromatography methods successfully resolved the major components with slightly different elution orders. The GC method was less satisfactory because it was unable to resolve mitragynine and speciociliatine. This separation was difficult by GC with a liquid stationary phase because these diastereoisomers differ only in the orientation of an interior hydrogen atom. The observed lack of resolution of the indole alkaloid diastereoisomers coupled with the likeness of the mass and tandem mass spectra, calls into question proposed GC methods for the analysis of mitragynine based on solely GC with MS separation and identification. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

4. Rapid Analysis Procedures for Triglycerides and Fatty Acids as Pentyl and Phenethyl Esters for the Detection of Butter Adulteration Using Chromatographic Techniques

Directory of Open Access Journals (Sweden)

Daniele Naviglio

2017-01-01

Full Text Available This paper presents the development of three methods for quality control, fraud detection, and authentication of butter fat and other oils/fats using chromatographic techniques, with one method for triglycerides and two methods for fatty acids (FAs. The procedure for the analysis of triglycerides requires only dissolution of the sample in n-hexane and gas chromatography (GC analysis using a capillary column. The second method is based on the transesterification of triglycerides as pentyl esters in a single-step reaction using sodium pentanoate in pentanol. The reaction proceeds at room temperature and is similar to the potassium hydroxide-catalysed transesterification of triglycerides with methanol and even more similar to the sodium methoxide method and sodium butanoate method. The advantage of using pentyl esters includes reducing the volatility of short-chain FAs, and substantial recoveries were obtained compared with methyl ester analysis. The third method involves the transesterification of triglycerides in fat through reaction with 2-phenylethanol in a single step; 2-phenylethanol possesses a chromophore, and the phenethyl esters formed are analysed by high-performance liquid chromatography (HPLC with UV detection.

5. Determination of Diffusion Coefficients and Activation Energy of Selected Organic Liquids using Reversed-Flow Gas Chromatographic Technique

International Nuclear Information System (INIS)

Khalisanni Khalid; Rashid Atta Khan; Sharifuddin Mohd Zain

2012-01-01

Evaporation of vaporize organic liquid has ecological consequences when the compounds are introduced into both freshwater and marine environments through industrial effluents, or introduced directly into the air from industrial unit processes such as bioreactors and cooling towers. In such cases, a rapid and simple method are needed to measure physicochemical properties of the organic liquids. The Reversed-Flow Gas Chromatography (RF-GC) sampling technique is an easy, fast and accurate procedure. It was used to measure the diffusion coefficients of vapors from liquid into a carrier gas and at the same time to determine the rate coefficients for the evaporation of the respective liquid. The mathematical expression describing the elution curves of the samples peaks was derived and used to calculate the respective parameters for the selected liquid pollutants selected such as methanol, ethanol, 1-propanol, 1-butanol, n-pentane, n-hexane, n-heptane and n-hexadecane, evaporating into the carrier gas of nitrogen. The values of diffusion coefficients found were compared with those calculated theoretically or reported in the literature. The values of evaporation rate were used to determine the activation energy of respective samples using Arrhenius equation. An interesting finding of this work is by using an alternative mathematical analysis based on equilibrium at the liquid-gas interphase, the comparison leads to profound agreement between theoretical values of diffusion coefficients and experimental evidence. (author)

6. A novel wireless modulation technique for inter-standard communications

NARCIS (Netherlands)

Bekkaoui, A.; Haartsen, J.C.

2006-01-01

A new technique is presented with permits transceivers of different radio standards to communicate with each other. Applications are found in unlicensed bands where radios using different technologies, like for example Bluetooth, ZigBee, or WLAN IEEE 802.11, have to share the same radio spectrum. If

7. Chromatographic finger print analysis of anti-inflammatory active extract fractions of aerial parts of Tribulus terrestris by HPTLC technique

Science.gov (United States)

Mohammed, Mona Salih; Alajmi, Mohamed Fahad; Alam, Perwez; Khalid, Hassan Subki; Mahmoud, Abelkhalig Muddathir; Ahmed, Wadah Jamal

2014-01-01

Objective To develop HPTLC fingerprint profile of anti-inflammatory active extract fractions of Tribulus terrestris (family Zygophyllaceae). Methods The anti-inflammatory activity was tested for the methanol and its fractions (chloroform, ethyl acetate, n-butanol and aqueous) and chloroform extract of Tribulus terrestris (aerial parts) by injecting different groups of rats (6 each) with carrageenan in hind paw and measuring the edema volume before and 1, 2 and 3 h after carrageenan injection. Control group received saline i.p. The extracts treatment was injected i.p. in doses of 200 mg/kg 1 h before carrageenan administration. Indomethacin (30 mg/kg) was used as standard. HPTLC studies were carried out using CAMAG HPTLC system equipped with Linomat IV applicator, TLC scanner 3, Reprostar 3, CAMAG ADC 2 and WIN CATS-4 software for the active fractions of chloroform fraction of methanol extract. Results The methanol extract showed good antiedematous effect with percentage of inhibition more than 72%, indicating its ability to inhibit the inflammatory mediators. The methanol extract was re-dissolved in 100 mL of distilled water and fractionated with chloroform, ethyl acetate and n-butanol. The four fractions (chloroform, ethyl acetate, n-butanol and aqueous) were subjected to anti-inflammatory activity. Chloroform fraction showed good anti-inflammatory activity at dose of 200 mg/kg. Chloroform fraction was then subjected to normal phase silica gel column chromatography and eluted with petroleum ether-chloroform, chloroform-ethyl acetate mixtures of increasing polarity which produced 15 fractions (F1-F15). Only fractions F1, F2, F4, F5, F7, F9, F11 and F14 were found to be active, hence these were analyzed with HPTLC to develop their finger print profile. These fractions showed different spots with different Rf values. Conclusions The different chloroform fractions F1, F2, F4, F5, F7, F9, F11 and F14 revealed 4, 7, 7, 8, 9, 7, 7 and 6 major spots, respectively. The

8. Chromatographic finger print analysis of anti-inflammatory active extract fractions of aerial parts of Tribulus terrestris by HPTLC technique.

Science.gov (United States)

Mohammed, Mona Salih; Alajmi, Mohamed Fahad; Alam, Perwez; Khalid, Hassan Subki; Mahmoud, Abelkhalig Muddathir; Ahmed, Wadah Jamal

2014-03-01

To develop HPTLC fingerprint profile of anti-inflammatory active extract fractions of Tribulus terrestris (family Zygophyllaceae). The anti-inflammatory activity was tested for the methanol and its fractions (chloroform, ethyl acetate, n-butanol and aqueous) and chloroform extract of Tribulus terrestris (aerial parts) by injecting different groups of rats (6 each) with carrageenan in hind paw and measuring the edema volume before and 1, 2 and 3 h after carrageenan injection. Control group received saline i.p. The extracts treatment was injected i.p. in doses of 200 mg/kg 1 h before carrageenan administration. Indomethacin (30 mg/kg) was used as standard. HPTLC studies were carried out using CAMAG HPTLC system equipped with Linomat IV applicator, TLC scanner 3, Reprostar 3, CAMAG ADC 2 and WIN CATS-4 software for the active fractions of chloroform fraction of methanol extract. The methanol extract showed good antiedematous effect with percentage of inhibition more than 72%, indicating its ability to inhibit the inflammatory mediators. The methanol extract was re-dissolved in 100 mL of distilled water and fractionated with chloroform, ethyl acetate and n-butanol. The four fractions (chloroform, ethyl acetate, n-butanol and aqueous) were subjected to anti-inflammatory activity. Chloroform fraction showed good anti-inflammatory activity at dose of 200 mg/kg. Chloroform fraction was then subjected to normal phase silica gel column chromatography and eluted with petroleum ether-chloroform, chloroform-ethyl acetate mixtures of increasing polarity which produced 15 fractions (F1-F15). Only fractions F1, F2, F4, F5, F7, F9, F11 and F14 were found to be active, hence these were analyzed with HPTLC to develop their finger print profile. These fractions showed different spots with different Rf values. The different chloroform fractions F1, F2, F4, F5, F7, F9, F11 and F14 revealed 4, 7, 7, 8, 9, 7, 7 and 6 major spots, respectively. The results obtained in this experiment

9. Standardization of surgical techniques used in facial bone contouring.

Science.gov (United States)

Lee, Tae Sung

2015-12-01

Since the introduction of facial bone contouring surgery for cosmetic purposes, various surgical methods have been used to improve the aesthetics of facial contours. In general, by standardizing the surgical techniques, it is possible to decrease complication rates and achieve more predictable surgical outcomes, thereby increasing patient satisfaction. The technical strategies used by the author to standardize facial bone contouring procedures are introduced here. The author uses various pre-manufactured surgical tools and hardware for facial bone contouring. During a reduction malarplasty or genioplasty procedure, double-bladed reciprocating saws and pre-bent titanium plates customized for the zygomatic body, arch and chin are used. Various guarded oscillating saws are used for mandibular angloplasty. The use of double-bladed saws and pre-bent plates to perform reduction malarplasty reduces the chances of post-operative asymmetry or under- or overcorrection of the zygoma contours due to technical faults. Inferior alveolar nerve injury and post-operative jawline asymmetry or irregularity can be reduced by using a guarded saw during mandibular angloplasty. For genioplasty, final placement of the chin in accordance with preoperative quantitative analysis can be easily performed with pre-bent plates, and a double-bladed saw allows more procedural accuracy during osteotomies. Efforts by the surgeon to avoid unintentional faults are key to achieving satisfactory results and reducing the incidence of complications. The surgical techniques described in this study in conjunction with various in-house surgical tools and modified hardware can be used to standardize techniques to achieve aesthetically gratifying outcomes. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

10. Standardized fluoroscopy-based technique to measure intraoperative cup anteversion.

Science.gov (United States)

Zingg, Matthieu; Boudabbous, Sana; Hannouche, Didier; Montet, Xavier; Boettner, Friedrich

2017-10-01

Direct anterior approach (DAA) with the patient lying supine has facilitated the use of intraoperative fluoroscopy and allows for standardized positioning of the patient. The current study presents a new technique to measure acetabular component anteversion using intraoperative fluoroscopy. The current paper describes a mathematical formula to calculate true acetabular component anteversion based on the acetabular component abduction angle and the c-arm tilt angle (CaT). The CaT is determined by tilting the c-arm until an external pelvic oblique radiograph with the equatorial plane of the acetabular component perpendicular to the fluoroscopy receptor is obtained. CaT is determined by direct reading on the C-arm device. The technique was validated using a radiopaque synbone model comparing the described technique to computed tomography anteversion measurement. The experiment was repeated 25 times. The difference in anteversion between the two measuring techniques was on average 0.2° (range -3.0-3.1). The linear regression coefficients evaluating the agreement between the experimental and control methods were 0.99 (95%CI 0.88-1.10, p < 0.001) and 0.33 (95%CI -1.53-2.20, p = 0.713) for the slope and intercept, respectively. The current study confirms that the described three-step c-arm acetabular cup measuring technique can reproducibly and reliably assess acetabular component anteversion in the supine position, as compared to CT-imaging. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2307-2312, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

11. Reef Fish Survey Techniques: Assessing the Potential for Standardizing Methodologies.

Directory of Open Access Journals (Sweden)

Zachary R Caldwell

Full Text Available Dramatic changes in populations of fishes living on coral reefs have been documented globally and, in response, the research community has initiated efforts to assess and monitor reef fish assemblages. A variety of visual census techniques are employed, however results are often incomparable due to differential methodological performance. Although comparability of data may promote improved assessment of fish populations, and thus management of often critically important nearshore fisheries, to date no standardized and agreed-upon survey method has emerged. This study describes the use of methods across the research community and identifies potential drivers of method selection. An online survey was distributed to researchers from academic, governmental, and non-governmental organizations internationally. Although many methods were identified, 89% of survey-based projects employed one of three methods-belt transect, stationary point count, and some variation of the timed swim method. The selection of survey method was independent of the research design (i.e., assessment goal and region of study, but was related to the researcher's home institution. While some researchers expressed willingness to modify their current survey protocols to more standardized protocols (76%, their willingness decreased when methodologies were tied to long-term datasets spanning five or more years. Willingness to modify current methodologies was also less common among academic researchers than resource managers. By understanding both the current application of methods and the reported motivations for method selection, we hope to focus discussions towards increasing the comparability of quantitative reef fish survey data.

12. Compressed air injection technique to standardize block injection pressures.

Science.gov (United States)

Tsui, Ban C H; Li, Lisa X Y; Pillay, Jennifer J

2006-11-01

Presently, no standardized technique exists to monitor injection pressures during peripheral nerve blocks. Our objective was to determine if a compressed air injection technique, using an in vitro model based on Boyle's law and typical regional anesthesia equipment, could consistently maintain injection pressures below a 1293 mmHg level associated with clinically significant nerve injury. Injection pressures for 20 and 30 mL syringes with various needle sizes (18G, 20G, 21G, 22G, and 24G) were measured in a closed system. A set volume of air was aspirated into a saline-filled syringe and then compressed and maintained at various percentages while pressure was measured. The needle was inserted into the injection port of a pressure sensor, which had attached extension tubing with an injection plug clamped "off". Using linear regression with all data points, the pressure value and 99% confidence interval (CI) at 50% air compression was estimated. The linearity of Boyle's law was demonstrated with a high correlation, r = 0.99, and a slope of 0.984 (99% CI: 0.967-1.001). The net pressure generated at 50% compression was estimated as 744.8 mmHg, with the 99% CI between 729.6 and 760.0 mmHg. The various syringe/needle combinations had similar results. By creating and maintaining syringe air compression at 50% or less, injection pressures will be substantially below the 1293 mmHg threshold considered to be an associated risk factor for clinically significant nerve injury. This technique may allow simple, real-time and objective monitoring during local anesthetic injections while inherently reducing injection speed.

13. Liquid chromatographic extraction medium

Science.gov (United States)

Horwitz, E. Philip; Dietz, Mark L.

1994-01-01

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

14. Standard Establishment Through Scenarios (SETS): A new technique for occupational fitness standards.

Science.gov (United States)

Blacklock, R E; Reilly, T J; Spivock, M; Newton, P S; Olinek, S M

2015-01-01

An objective and scientific task analysis provides the basis for establishing legally defensible Physical Employment Standards (PES), based on common and essential occupational tasks. Infrequent performance of these tasks creates challenges when developing PES based on criterion, or content validity. Develop a systematic approach using Subject Matter Experts (SME) to provide tasks with 1) an occupationally relevant scenario considered common to all personnel; 2) a minimum performance standard defined by time, distance, load or work. Examples provided here relate to the development of a new PES for the Canadian Armed Forces (CAF). SME of various experience are selected based on their eligibility criteria. SME are required to define a reasonable scenario for each task from personal experience, provide occupational performance requirements of the scenario in sub-groups, and discuss and agree by consensus vote on the final standard based on the definition of essential. A common and essential task for the CAF is detailed as a case example of process application. Techniques to avoid common SME rating errors are discussed and advantages to the method described. The SETS method was developed as a systematic approach to setting occupational performance standards and qualifying information from SME.

15. NET European Network on Neutron Techniques Standardization for Structural Integrity

International Nuclear Information System (INIS)

Youtsos, A.

2004-01-01

Improved performance and safety of European energy production systems is essential for providing safe, clean and inexpensive electricity to the citizens of the enlarged EU. The state of the art in assessing internal stresses, micro-structure and defects in welded nuclear components -as well as their evolution due to complex thermo-mechanical loads and irradiation exposure -needs to be improved before relevant structural integrity assessment code requirements can safely become less conservative. This is valid for both experimental characterization techniques and predictive numerical algorithms. In the course of the last two decades neutron methods have proven to be excellent means for providing valuable information required in structural integrity assessment of advanced engineering applications. However, the European industry is hampered from broadly using neutron research due to lack of harmonised and standardized testing methods. 35 European major industrial and research/academic organizations have joined forces, under JRC coordination, to launch the NET European Network on Neutron Techniques Standardization for Structural Integrity in May 2002. The NET collaborative research initiative aims at further development and harmonisation of neutron scattering methods, in support of structural integrity assessment. This is pursued through a number of testing round robin campaigns on neutron diffraction and small angle neutron scattering - SANS and supported by data provided by other more conventional destructive and non-destructive methods, such as X-ray diffraction and deep and surface hole drilling. NET also strives to develop more reliable and harmonized simulation procedures for the prediction of residual stress and damage in steel welded power plant components. This is pursued through a number of computational round robin campaigns based on advanced FEM techniques, and on reliable data obtained by such novel and harmonized experimental methods. The final goal of

16. Chromatographic hydrogen isotope separation

International Nuclear Information System (INIS)

Aldridge, F.T.

1983-01-01

Intermetallic compounds with the CaCu5 type of crystal structure, particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

17. Chromatographic hydrogen isotope separation

Science.gov (United States)

Aldridge, F.T.

Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

18. Linear regression analysis and its application to multivariate chromatographic calibration for the quantitative analysis of two-component mixtures.

Science.gov (United States)

Dinç, Erdal; Ozdemir, Abdil

2005-01-01

Multivariate chromatographic calibration technique was developed for the quantitative analysis of binary mixtures enalapril maleate (EA) and hydrochlorothiazide (HCT) in tablets in the presence of losartan potassium (LST). The mathematical algorithm of multivariate chromatographic calibration technique is based on the use of the linear regression equations constructed using relationship between concentration and peak area at the five-wavelength set. The algorithm of this mathematical calibration model having a simple mathematical content was briefly described. This approach is a powerful mathematical tool for an optimum chromatographic multivariate calibration and elimination of fluctuations coming from instrumental and experimental conditions. This multivariate chromatographic calibration contains reduction of multivariate linear regression functions to univariate data set. The validation of model was carried out by analyzing various synthetic binary mixtures and using the standard addition technique. Developed calibration technique was applied to the analysis of the real pharmaceutical tablets containing EA and HCT. The obtained results were compared with those obtained by classical HPLC method. It was observed that the proposed multivariate chromatographic calibration gives better results than classical HPLC.

19. [Study on standardization of cupping technique: elucidation on the establishment of the National Standard Standardized Manipulation of Acupuncture and Moxibustion, Part V, Cupping].

Science.gov (United States)

Gao, Shu-zhong; Liu, Bing

2010-02-01

From the aspects of basis, technique descriptions, core contents, problems and solutions, and standard thinking in standard setting process, this paper states experiences in the establishment of the national standard Standardized Manipulation of Acupuncture and Moxibustion, Part V, Cupping, focusing on methodologies used in cupping standard setting process, the method selection and operating instructions of cupping standardization, and the characteristics of standard TCM. In addition, this paper states the scope of application, and precautions for this cupping standardization. This paper also explaines tentative ideas on the research of standardized manipulation of acupuncture and moxibustion.

20. Effects of chromatographic fractions of Euphorbia hirta on the rat ...

African Journals Online (AJOL)

The ethanolic extract of this plant was subjected to chromatographic separation using the vacuum liquid chromatographic technique, a modified form of classical column chromatography. With the aid of thin layer chromatography, six fractions of this plant were obtained and were administered to rats in graded doses of ...

1. MICROSCOPIC, PHYSICOCHEMICAL AND CHROMATOGRAPHIC ...

African Journals Online (AJOL)

Peters

MICROSCOPIC, PHYSICOCHEMICAL AND CHROMATOGRAPHIC. FINGERPRINTS OF LEAVES OF NIGERIAN CASSIA TORA LINN. Fatokun Omolola T1*., EsievoKevwe B2., Ugbabe Grace E3. and Kunle Oluyemisi F4. Department of Medicinal Plant Research and Traditional Medicine, National Institute for.

2. A rapid, solid phase extraction (SPE technique for the extraction and gas chromatographic determination lindane pesticide residue in tissue and milk

Directory of Open Access Journals (Sweden)

Yuningsih

2006-03-01

Full Text Available Organochlorine pesticide contamination in feed can cause residue in animal product (tissue and milk, so its become a problem in food safety. Solid phase extraction (SPE has been carried out for determination organochlorine pesticide residues in food animal production. The technique was rapid, not costly and produce limited amount of hazardous-waste. Samples were homogenized with acetonitrile trough cartridge C18, eluted in fluorocyl column with 2% ether-petroleum or acetonitrile fortissue and milk samples respectively. The recoveries of tissue sample by addition lindane standard solution: 0.50 and 1.00 μg are 85.10 and 103.10% respectively, while that of milk with the addition of 0.50, 1.00 and 1.50 μg are 83.80, 88.69 and 91.24% respectively. Three replicates were carried out for every sample. According of validation criteria of FAO/IAEA the recovery for analysis of pesticide residues was 70-110%. Therefore, the method is applicable.

3. Analysis of Reaction between α-Lipoic Acid and 2-Chloro-1-methylquinolinium Tetrafluoroborate Used as a Precolumn Derivatization Technique in Chromatographic Determination of α-Lipoic Acid

Directory of Open Access Journals (Sweden)

Magdalena Godlewska

2015-01-01

Full Text Available The present study offers results of analysis concerning the course of reaction between reduced α-lipoic acid (LA and 2-chloro-1-methylquinolinium tetrafluoroborate (CMQT. In water environments, the reaction between CMQT and hydrophilic thiols proceeds very rapidly and the resultant products are stable. For the described analysis, optimum reaction conditions, such as concentration of the reducing agent, environment pH, and concentration of the reagent were carefully selected. The spectrophotometric assay was carried out measuring absorbance at λ=348 nm (i.e., the spectral band of the obtained reaction product. Furthermore, the calibration curve of lipoic acid was registered. It was concluded that the Lambert-Beer law was observed within the range 1–10 μmol L−1. Later, the reaction between LA and CMQT was used as precolumn derivatization in a chromatographic determination of the lipoic acid in the range 2.5–50 μmol L−1. Practical applicability of the designed methods was evaluated by determining lipoic acid in Revitanerv pharmaceutical preparation which contains 300 mg LA in a single capsule. The error of the determination did not exceed 0.5% in relation to the declared value.

4. Portable gas chromatograph-mass spectrometer

Science.gov (United States)

Andresen, B.D.; Eckels, J.D.; Kimmons, J.F.; Myers, D.W.

1996-06-11

A gas chromatograph-mass spectrometer (GC-MS) is described for use as a field portable organic chemical analysis instrument. The GC-MS is designed to be contained in a standard size suitcase, weighs less than 70 pounds, and requires less than 600 watts of electrical power at peak power (all systems on). The GC-MS includes: a conduction heated, forced air cooled small bore capillary gas chromatograph, a small injector assembly, a self-contained ion/sorption pump vacuum system, a hydrogen supply, a dual computer system used to control the hardware and acquire spectrum data, and operational software used to control the pumping system and the gas chromatograph. This instrument incorporates a modified commercial quadrupole mass spectrometer to achieve the instrument sensitivity and mass resolution characteristic of laboratory bench top units. 4 figs.

5. Optimization of the gas chromatographic separations

International Nuclear Information System (INIS)

Gasco Sanchez, L.

1973-01-01

A review and a critical study on the optimization of the gas chromatographic separations are made. After dealing with the fundamental gas chromatographic equations, some methods of expressing column performances are discussed: performance indices, performance parameters, resolution and effective plate number per unit time. This is completed with a comparative study on performances of various types of columns. Moreover, optimization methods for operating chromatographic conditions are extensively dealt with: as resolution optimization, separation time, and normalization techniques for the time of analysis in order to achieve the maximum resolution at constant time. Finally, some others non operating parameters such as: selectivity of stationary phases, column preparation and optimization methods by means of computers are studied. (Author) 68 refs

6. Ion chromatographic determination of Di-n-butyl phosphate in degraded organic solvent

International Nuclear Information System (INIS)

Velavendan, P.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

2011-01-01

In the present work a method for the determination of Di-n-butyl phosphate in organic streams using Ion Chromatography technique is developed and described here. The method involves the separation of Di-n-butyl phosphate (DBP) from 30% TBP-NPH (Tri-n-butylphosphate diluted in Normal Paraffin Hydrocarbon) and uranium/nitric acid matrix by an extraction of DBP in alkaline medium and subsequent ion-exchange separation in ion chromatography column followed by suppressed conductivity detection. Direct determination of DBP in lean/loaded organic solvent will lead to in accurate determination of DBP due to organic interference. DBP is quantified to lower limit of 1 ppm with 3% RSD. The results obtained with ion chromatographic technique are compared with those obtained by standard gas chromatographic technique. The developed method is much faster and total analysis can be completed within two hours. (author)

7. Gas chromatographic determination of Di-n-butyl phosphate in radioactive lean organic solvent of FBTR carbide fuel reprocessing

International Nuclear Information System (INIS)

Velavendan, P.; Ganesh, S.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

2011-01-01

In the present work Di-n- butyl phosphate (DBP) a degraded product of Tri-n-butyl phosphate (TBP) formed by acid hydrolysis and radiolysis in the PUREX process was analyzed. Lean organic streams of different fuel burn-up FBTR carbide fuel reprocessing solution was determined by standard Gas Chromatographic technique. The method involves the conversion of non-volatile Di-n-butyl phosphate into volatile and stable derivatives by the action of diazomethane and then determined by Gas Chromatograph (GC). A calibration graph was made for DBP concentration range of 200-2000 ppm with correlation coefficient of 0.99587 and RSD 1.2 %. (author)

8. Technique for fabrication of gradual standards of radiographic image blachening density

International Nuclear Information System (INIS)

Borovin, I.V.; Kondina, M.A.

1987-01-01

The technique of fabrication of gradual standards of blackening density for industrial radiography by contact printing from a negative is described. The technique is designed for possibilities of industrial laboratoriesof radiation defectoscopy possessing no special-purpose sensitometric equipment

9. Basic prediction techniques in modern video coding standards

CERN Document Server

Kim, Byung-Gyu

2016-01-01

This book discusses in detail the basic algorithms of video compression that are widely used in modern video codec. The authors dissect complicated specifications and present material in a way that gets readers quickly up to speed by describing video compression algorithms succinctly, without going to the mathematical details and technical specifications. For accelerated learning, hybrid codec structure, inter- and intra- prediction techniques in MPEG-4, H.264/AVC, and HEVC are discussed together. In addition, the latest research in the fast encoder design for the HEVC and H.264/AVC is also included.

10. Preliminary detection of explosive standard components with Laser Raman Technique

International Nuclear Information System (INIS)

Botti, S.; Ciardi, R.

2008-01-01

Presently, our section is leader of the ISOTREX project (Integrated System for On-line TRace EXplosives detection in solid, liquid and vapour state), funded in the frame of the PASR 2006 action (Preparatory Action on the enhancement of the European industrial potential in the field of Security Research Preparatory Action) of the 6. EC framework. ISOTREX project will exploit the capabilities of different laser techniques as LIBS (Laser Induced Breakdown Spectroscopy), LPA (Laser Photo Acustic) and CRDS (Cavity Ring Down Spectroscopy) to monitor explosive traces. In this frame, we extended our investigation also to the laser induced Raman effect spectroscopy, in order to investigate its capabilities and possible future integration. We analysed explosive samples in bulk solid phase, diluted liquid phase and as evaporated films over suitable substrate. In the following, we present the main results obtained, outlining preliminary conclusions [it

11. Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

DEFF Research Database (Denmark)

Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

1993-01-01

to arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant......Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate...

12. [The gas chromatographic analysis of volatile compounds on the compact MKhP chromatograph].

Science.gov (United States)

Krasnova, R R; Ianovskiĭ, S M

1998-01-01

Methods of analysis of biological specimens, alcohol beverages, and technological liquids in columns with standard adsorbents carbopaque B and C with carbowax 20M, widely used abroad, are described and examples of analyses presented. A special portable chromatographer (MCP) with flame ionization detector has been designed. It is intended for analysis of volatile organic compounds (alcohols, carbohydrates, organochlorine compounds, glycols, esters, etc.) in columns of different polarity. The system of processing of chromatographic findings permits a quantitative analysis of complex chromatograms and automated identification of substances in biological samples by using the available database.

13. Application of ethyl esters and d3-methyl esters as internal standards for the gas chromatographic quantification of transesterified fatty acid methyl esters in food.

Science.gov (United States)

2006-05-03

Ethyl esters (FAEE) and trideuterium-labeled methyl esters (d3-FAME) of fatty acids were prepared and investigated regarding their suitability as internal standards (IS) for the determination of fatty acids as methyl esters (FAME). On CP-Sil 88, ethyl esters of odd-numbered fatty acids eluted approximately 0.5 min after the respective FAME, and only coelutions with minor FAME were observed. Depending on the problem, one or even many FAEE can be added as IS for the quantification of FAME by both GC-FID and GC-MS. By contrast, d3-FAME coeluted with FAME on the polar GC column, and the use of the former as IS requires application of GC-MS. In the SIM mode, m/z 77 and 90 are suggested for d3-methyl esters of saturated fatty acids, whereas m/z 88 and 101 are recommended for ethyl esters of saturated fatty acids. These m/z values give either no or very low response for FAME and can thus be used for the analysis of FAME in food by GC-MS in the SIM mode. Fatty acids in sunflower oil and mozzarella cheese were quantified using five saturated FAEE as IS. Gravimetric studies showed that the transesterification procedure could be carried out without of loss of fatty acids. GC-EI/MS full scan analysis was suitable for the quantitative determination of all unsaturated fatty acids in both food samples, whereas GC-EI/MS in the SIM mode was particularly valuable for quantifying minor fatty acids. The novel GC-EI/MS/SIM method using fatty acid ethyl esters as internal standards can be used to quantify individual fatty acids only, that is, without determination of all fatty acids (the common 100% method), although this is present. This was demonstrated by the exclusive quantification of selected fatty acids including methyl-branched fatty acids, erucic acid (18:1n-9trans), and polyunsaturated fatty acids in cod liver oil and goat's milk fat.

14. Amalgam-chromatographic separation of magnesium isotopes

International Nuclear Information System (INIS)

Klinskij, G.D.; Levkin, A.V.; Ivanov, S.A.

1990-01-01

Separation of magnesium isotopes within Mg(Hg)-MgI 2 system (in dimethylformamide) is conducted under amalgam-chromatographic conditions. Separation maximal degree, that is (1.09), for 24 Mg and 26 Mg and separation coefficient (α = 1.0089±0.006) are determined. Light isotopes are found to concentrate in the amalgam. Technique of thermal conversion of flows within amalgam-dimethylformamide system is suggested on the basis of reversible reaction of Ca-Mg element exchange

15. Technology and Technique Standards for Camera-Acquired Digital Dermatologic Images: A Systematic Review.

Science.gov (United States)

Quigley, Elizabeth A; Tokay, Barbara A; Jewell, Sarah T; Marchetti, Michael A; Halpern, Allan C

2015-08-01

Photographs are invaluable dermatologic diagnostic, management, research, teaching, and documentation tools. Digital Imaging and Communications in Medicine (DICOM) standards exist for many types of digital medical images, but there are no DICOM standards for camera-acquired dermatologic images to date. To identify and describe existing or proposed technology and technique standards for camera-acquired dermatologic images in the scientific literature. Systematic searches of the PubMed, EMBASE, and Cochrane databases were performed in January 2013 using photography and digital imaging, standardization, and medical specialty and medical illustration search terms and augmented by a gray literature search of 14 websites using Google. Two reviewers independently screened titles of 7371 unique publications, followed by 3 sequential full-text reviews, leading to the selection of 49 publications with the most recent (1985-2013) or detailed description of technology or technique standards related to the acquisition or use of images of skin disease (or related conditions). No universally accepted existing technology or technique standards for camera-based digital images in dermatology were identified. Recommendations are summarized for technology imaging standards, including spatial resolution, color resolution, reproduction (magnification) ratios, postacquisition image processing, color calibration, compression, output, archiving and storage, and security during storage and transmission. Recommendations are also summarized for technique imaging standards, including environmental conditions (lighting, background, and camera position), patient pose and standard view sets, and patient consent, privacy, and confidentiality. Proposed standards for specific-use cases in total body photography, teledermatology, and dermoscopy are described. The literature is replete with descriptions of obtaining photographs of skin disease, but universal imaging standards have not been developed

16. Novel preconcentration technique for on-line coupling to high-speed narrow-bore capillary gas chromatography: sample enrichment by equilibrium (ab)sorption. II. Coupling to a portable micro gas chromatograph.

Science.gov (United States)

Tuan, H P; Janssen, H G; Cramers, C A; Mussche, P; Lips, J; Wilson, N; Handley, A

1997-12-12

The technique of equilibrium (ab)sorption has been proven to be a powerful method for preconcentration of gaseous samples for high-speed narrow-bore capillary gas chromatography (GC) in general and field-portable GC instruments, often referred as micro GCs, in particular. Using a simple experimental set-up equipped with an open-tubular enrichment column it is possible to produce a homogeneously enriched sample plug, allowing reproducible injections of an enriched sample into the micro GC. Using a non-polar trapping column enrichment factors found for n-alkanes in the range of C7 to C10 ranged from 15 to 150 and agree well with calculated values. Using a highly retentive Thermocap column, the enrichment factor observed for heptane was above 500. As the use of this new preconcentration method requires only minimum modification of the micro GC, the chromatographic performance of the instrument was not compromised by direct coupling to the preconcentration device. Examples of on-line enrichment with portable micro GC analysis of VOCs from air are shown. These examples clearly demonstrate the potentials of the new method in field analysis.

17. Utility of chromatographic and spectroscopic techniques for a detailed characterization of poly(styrene-b-isoprene) miktoarm star copolymers with complex architecture

KAUST Repository

Šmigovec Ljubič, Tina

2012-09-25

We analyzed various miktoarm star copolymers of the PS(PI) x type (x = 2, 3, 5, 7), which consist of one long polystyrene (PS) arm (82 or 105 kDa) and various numbers of short polyisoprene (PI) arms (from 11.3 to 39.7 kDa), prepared by anionic polymerization and selective chlorosilane chemistry. The length of the PI arm in stars decreases with the number of arms, so that the chemical compositions of all PS(PI) x samples were comparable. Our aim was to determine the purity of samples and to identify exactly the constituents of individual samples. For this purpose we used a variety of separation techniques (size-exclusion chromatography (SEC), reversed-phase liquid-adsorption chromatography (RP-LAC), and two-dimensional liquid chromatography (2D-LC)) and characterization techniques (UV-MALS-RI multidetection SEC system, NMR, and MALDI-TOF MS). The best separation and identification of the samples\\' constituents were achieved by RP-LAC, which separates macromolecules according to their chemical composition, and a subsequent analysis of the off-line collected fractions from the RP-C18 column by SEC/UV-MALS-RI multidetection system. The results showed that all PS(PI) x samples contained the homo-PS and homo-PI in minor amounts and the high-molar-mass (PS) y(PI) z (y > 1) species, the content of which is higher in the samples PS(PI) 5 and PS(PI) 7 than in the samples PS(PI) 2 and PS(PI) 3. The major constituent of the PS(PI) 2 sample was the one with the predicted structure. On the other hand, the major components of the PS(PI) x (x = 3, 5, and 7) samples were the stars consisting of a smaller number of PI arms than predicted from the functionalities of chlorosilane coupling agents. These results are in agreement with the average chemical composition of samples determined by proton NMR spectroscopy and characterization of the constituents by MALDI-TOF MS. © 2012 American Chemical Society.

18. Total milk fat extraction and quantification of polar and neutral lipids of cow, goat, and ewe milk by using a pressurized liquid system and chromatographic techniques.

Science.gov (United States)

Castro-Gómez, M P; Rodriguez-Alcalá, L M; Calvo, M V; Romero, J; Mendiola, J A; Ibañez, E; Fontecha, J

2014-11-01

Although milk polar lipids such as phospholipids and sphingolipids located in the milk fat globule membrane constitute 0.1 to 1% of the total milk fat, those lipid fractions are gaining increasing interest because of their potential beneficial effects on human health and technological properties. In this context, the accurate quantification of the milk polar lipids is crucial for comparison of different milk species, products, or dairy treatments. Although the official International Organization for Standardization-International Dairy Federation method for milk lipid extraction gives satisfactory results for neutral lipids, it has important disadvantages in terms of polar lipid losses. Other methods using mixtures of solvents such as chloroform:methanol are highly efficient for extracting polar lipids but are also associated with low sample throughput, long time, and large solvent consumption. As an alternative, we have optimized the milk fat extraction yield by using a pressurized liquid extraction (PLE) method at different temperatures and times in comparison with those traditional lipid extraction procedures using 2:1 chloroform:methanol as a mixture of solvents. Comparison of classical extraction methods with the developed PLE procedure were carried out using raw whole milk from different species (cows, ewes, and goats) and considering fat yield, fatty acid methyl ester composition, triacylglyceride species, cholesterol content, and lipid class compositions, with special attention to polar lipids such as phospholipids and sphingolipids. The developed PLE procedure was validated for milk fat extraction and the results show that this method performs a complete or close to complete extraction of all lipid classes and in less time than the official and Folch methods. In conclusion, the PLE method optimized in this study could be an alternative to carry out milk fat extraction as a routine method. Copyright © 2014 American Dairy Science Association. Published by

19. Standardization of proton-induced x-ray emission technique for analysis of thick samples

Science.gov (United States)

2015-09-01

This paper describes the standardization of the proton-induced x-ray emission (PIXE) technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials (SRMs) were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 MeV obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.

20. A comparison between two lateral cephalometry techniques (standard and natural head position

Directory of Open Access Journals (Sweden)

Hedayati Z. Assistant Professor. Sang S. DMD

2003-06-01

Full Text Available Statement of Problem: Cephalometric findings are of high importance in making decision about orthodontic treatment plans and orthognathic surgeries. Natural head position (NHP is considered as a useful and exact radiographic technique."nAim: The aim of the present study was to compare two techniques, namely Standard and NHP, in lateral"ncephalometry."nMaterials and Methods: In this cross- sectional study, performed in Shiraz. 138 randomly selected students {70 males .and 68 females, age ranging from (13-15. were evaluated clinically and radiographically. None of them had a history of orthodontic treatment, head and face fracture or surgical operations. Lateral cephalograms were taken in both standard and natural head position techniques, for each student. For statistical analysis, l-lest for paired samples, was done."nResults: This study showed that in anterior-posterior dimension, among angles with significant differences in two techniques, those of standard one were more reliable, whereas in vertical dimension."nstatistical differences showed natural technique as more useful one."nConclusion: Due to the fact that natural cephalometry requires more patient cooperation, more time and a higher complex technique, it is not suggested, except when different clinical and cepholomeiric findings are observed.

1. Laryngeal mask airway insertion in children: comparison between rotational, lateral and standard technique.

Science.gov (United States)

Ghai, Babita; Makkar, Jeetinder Kaur; Bhardwaj, Neerja; Wig, Jyotsna

2008-04-01

The purpose of the study was to compare the success and ease of insertion of three techniques of laryngeal mask airway (LMA) insertion; the standard Brain technique, a lateral technique with cuff partially inflated and a rotational technique with cuff partially inflated. One hundred and sixty-eight ASA I and II children aged 6 months to 6 years undergoing short elective surgical procedures lasting 40-60 min were included in the study. A standard anesthesia protocol was followed for all patients. Patients were randomly allocated into one of the three groups i.e. standard (S), rotational (R) and lateral (L). The primary outcome measure of the study was success rate at the first attempt using three techniques of LMA insertion. Secondary outcomes measures studied were overall success rate, time before successful LMA insertion, complications and maneuvers used to relieve airway obstruction. Successful insertion at the first attempt was significantly higher in group R (96%) compared with group L (84%) and group S (80%) (P = 0.03). Overall success rate (i.e. successful insertion with two attempts) was 100% for group R, 93% for group L and 87% for group S (P = 0.03). Time for successful insertion was significantly lower in group R compared with group L and S (P insertion and lowest incidence of complications and could be the technique of first choice for LMA insertion in pediatric patients.

2. Evaluation of coverage, retention patterns, and selectivity of seven liquid chromatographic methods for metabolomics.

Science.gov (United States)

Wernisch, Stefanie; Pennathur, Subramaniam

2016-09-01

Liquid chromatography-mass spectrometry-based metabolomics studies require highly selective and efficient chromatographic techniques. Typically employed reversed-phase (RP) methods fail to target polar metabolites, but the introduction of hydrophilic interaction liquid chromatography (HILIC) is slow due to perceived issues of reproducibility and ruggedness and a limited understanding of the complex retention mechanisms. In this study, we present a comparison of the chromatographic performance of a traditional RP-C18 column with zwitterionic, amide-, alkyl diol-, and aminoalkyl-based HILIC and mixed-mode columns. Our metabolite library represents one of the largest analyte sets available and consists of 764 authentic metabolite standards, including amino acids, nucleotides, sugars, and other metabolites, representing all major biological pathways and commonly observed exogenous metabolites (drugs). The coverage, retention patterns, and selectivity of the individual methods are highly diverse even between conceptually related HILIC methods. Furthermore, we show that HILIC sorbents having highly orthogonal selectivity and specificity enhance the coverage of major metabolite groups in (semi-) targeted applications compared to RP. Finally, we discuss issues encountered in the analysis of biological samples based on the results obtained with human plasma extracts. Our results demonstrate that fast and highly reproducible separations on zwitterionic columns are feasible, but knowledge of analyte properties is essential to avoid chromatographic bias and exclusion of key analytes in metabolomics studies. Graphical Abstract The chromatographic parameters of 764 authentic metabolite standards provide the basis for a comparison of coverage, selectivity and orthogonality of 7 reversed-phase (RP), mixed-mode (MM) and hydrophilic interaction liquid chromatography (HILIC) methods.

3. Dual liquid and gas chromatograph system

Science.gov (United States)

Gay, D.D.

A chromatographic system is described that utilizes one detection system for gas chromatographic and micro-liquid chromatographic determinations. The detection system is a direct-current, atmospheric-pressure, helium plasma emission spectrometer. The detector utilizes a nontransparent plasma source unit which contains the plasma region and two side-arms which receive effluents from the micro-liquid chromatograph and the gas chromatograph. The dual nature of this chromatographic system offers: (1) extreme flexibility in the samples to be examined; (2) extreme low sensitivity; (3) element selectivity; (4) long-term stability; (5) direct correlation of data from the liquid and gas samples; (6) simpler operation than with individual liquid and gas chromatographs, each with different detection systems; and (7) cheaper than a commercial liquid chromatograph and a gas chromatograph.

4. Standard techniques for presentation and analysis of crater size-frequency data

Science.gov (United States)

1978-01-01

In September 1977, a crater studies workshop was held for the purpose of developing standard data analysis and presentation techniques. This report contains the unanimous recommendations of the participants. This first meeting considered primarily crater size-frequency data. Future meetings will treat other aspects of crater studies such as morphologies.

5. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

Energy Technology Data Exchange (ETDEWEB)

Nah, Kyung Soo; Kim, Ae Ji [Dept. of Oral Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of); Doh, Shi Hong [Dept. of Applied physics . National Fisheries University of Pusan Department of Radiotherapy, Pusan (Korea, Republic of); Kim, Hyun Ja [Dept. of Oral Radiology, Baptist Hospital, Pusan (Korea, Republic of); Yoo, Meong Jin [Dept. of Radiology, College of Dentistry, Pusan National University, Pusan (Korea, Republic of)

1990-08-15

This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

6. Skin Absorbed Doses from Full Mouth Standard Intraoral Radiography in Bisecting Angle and Paralleling techniques

International Nuclear Information System (INIS)

Nah, Kyung Soo; Kim, Ae Ji; Doh, Shi Hong; Kim, Hyun Ja; Yoo, Meong Jin

1990-01-01

This study was performed to measure the skin absorbed doses from full mouth standard intraoral radiography(14 exposures) in bisecting angle and paralleling techniques. Thermoluminescent dosimeters were used in a phantom. Circular tube collimator (60 mm in diameter, 20 cm in length) and rectangular collimator (35 mm X 44 mm, 40 cm in length) were set for bisecting angle and paralleling techniques respectively. All measurement sites were classified into 8 groups according to distance from each point of central rays. The results were as follows: 1. The skin absorbed doses from the paralleling technique were significantly decreased than those from the bisecting technique in both points at central ray and points away from central ray. The percentage rats of decrease were greater at points away from central ray than those at central ray. 2. The skin absorbed doses at the lens of eye, parotid gland, submandibular gland and thyroid region were significantly decreased in paralleling technique, but those of the midline of palate remained similar in both techniques. 3. The highest doses were measured at the site 20 mm above the point of central ray for the mandibular premolars in bisecting angle technique and at the point of central ray for the mandibular premolars in paralleling techniques. The lowest doses were measured at the thyroid region in both techniques.

7. Elemental analyses of goundwater: demonstrated advantage of low-flow sampling and trace-metal clean techniques over standard techniques

Science.gov (United States)

Creasey, C. L.; Flegal, A. R.

The combined use of both (1) low-flow purging and sampling and (2) trace-metal clean techniques provides more representative measurements of trace-element concentrations in groundwater than results derived with standard techniques. The use of low-flow purging and sampling provides relatively undisturbed groundwater samples that are more representative of in situ conditions, and the use of trace-element clean techniques limits the inadvertent introduction of contaminants during sampling, storage, and analysis. When these techniques are applied, resultant trace-element concentrations are likely to be markedly lower than results based on standard sampling techniques. In a comparison of data derived from contaminated and control groundwater wells at a site in California, USA, trace-element concentrations from this study were 2-1000 times lower than those determined by the conventional techniques used in sampling of the same wells prior to (5months) and subsequent to (1month) the collections for this study. Specifically, the cadmium and chromium concentrations derived using standard sampling techniques exceed the California Maximum Contaminant Levels (MCL), whereas in this investigation concentrations of both of those elements are substantially below their MCLs. Consequently, the combined use of low-flow and trace-metal clean techniques may preclude erroneous reports of trace-element contamination in groundwater. Résumé L'utilisation simultanée de la purge et de l'échantillonnage à faible débit et des techniques sans traces de métaux permet d'obtenir des mesures de concentrations en éléments en traces dans les eaux souterraines plus représentatives que les résultats fournis par les techniques classiques. L'utilisation de la purge et de l'échantillonnage à faible débit donne des échantillons d'eau souterraine relativement peu perturbés qui sont plus représentatifs des conditions in situ, et le recours aux techniques sans éléments en traces limite l

8. Standardization of the Descemet membrane endothelial keratoplasty technique: Outcomes of the first 450 consecutive cases.

Science.gov (United States)

Satué, M; Rodríguez-Calvo-de-Mora, M; Naveiras, M; Cabrerizo, J; Dapena, I; Melles, G R J

2015-08-01

To evaluate the clinical outcome of the first 450 consecutive cases after Descemet membrane endothelial keratoplasty (DMEK), as well as the effect of standardization of the technique. Comparison between 3 groups: Group I: (cases 1-125), as the extended learning curve; Group II: (cases 126-250), transition to technique standardization; Group III: (cases 251-450), surgery with standardized technique. Best corrected visual acuity, endothelial cell density, pachymetry and intra- and postoperative complications were evaluated before, and 1, 3 and 6 months after DMEK. At 6 months after surgery, 79% of eyes reached a best corrected visual acuity of≥0.8 and 43%≥1.0. Mean preoperative endothelial cell density was 2,530±220 cells/mm2 and 1,613±495 at 6 months after surgery. Mean pachymetry measured 668±92 μm and 526±46 μm pre- and (6 months) postoperatively, respectively. There were no significant differences in best corrected visual acuity, endothelial cell density and pachymetry between the 3 groups (P > .05). Graft detachment presented in 17.3% of the eyes. The detachment rate declined from 24% to 12%, and the rate of secondary surgeries from 9.6% to 3.5%, from group I to III respectively. Visual outcomes and endothelial cell density after DMEK are independent of the technique standardization. However, technique standardization may have contributed to a lower graft detachment rate and a relatively low number of secondary interventions required. As such, DMEK may become the first choice of treatment in corneal endothelial disease. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

9. A survey on development of neutron standards and neutron measurement technique corresponding to various fields

International Nuclear Information System (INIS)

Matsumoto, Tetsuro

2007-01-01

Various uses of neutrons are being watched in many fields such as industry, medical technology and radiation protection. Especially, high energy neutrons above 15 MeV are important in a radiation exposure issue of an aircraft and a soft error issue of a semiconductor. Therefore neutron fluence standards for the high energy region are very important. However, the standards are not almost provided all over the world. Three reasons are mainly considered: (1) poor measurement techniques for the high energy neutrons, (2) a small number of high energy neutron facilities and (3) lack of nuclear data for high energy particle reactions. In this paper, the present status of the measurement techniques, the facilities and the nuclear data is investigated and discussed. In NMIJ/AIST, the 19.0-MeV neutron fluence standard will be established by 2010, and development of high energy neutron standards above 20 MeV is also examined. An outline of the development of the high energy neutron standards is also shown in this paper. (author)

10. A no-gold-standard technique for objective assessment of quantitative nuclear-medicine imaging methods.

Science.gov (United States)

Jha, Abhinav K; Caffo, Brian; Frey, Eric C

2016-04-07

The objective optimization and evaluation of nuclear-medicine quantitative imaging methods using patient data is highly desirable but often hindered by the lack of a gold standard. Previously, a regression-without-truth (RWT) approach has been proposed for evaluating quantitative imaging methods in the absence of a gold standard, but this approach implicitly assumes that bounds on the distribution of true values are known. Several quantitative imaging methods in nuclear-medicine imaging measure parameters where these bounds are not known, such as the activity concentration in an organ or the volume of a tumor. We extended upon the RWT approach to develop a no-gold-standard (NGS) technique for objectively evaluating such quantitative nuclear-medicine imaging methods with patient data in the absence of any ground truth. Using the parameters estimated with the NGS technique, a figure of merit, the noise-to-slope ratio (NSR), can be computed, which can rank the methods on the basis of precision. An issue with NGS evaluation techniques is the requirement of a large number of patient studies. To reduce this requirement, the proposed method explored the use of multiple quantitative measurements from the same patient, such as the activity concentration values from different organs in the same patient. The proposed technique was evaluated using rigorous numerical experiments and using data from realistic simulation studies. The numerical experiments demonstrated that the NSR was estimated accurately using the proposed NGS technique when the bounds on the distribution of true values were not precisely known, thus serving as a very reliable metric for ranking the methods on the basis of precision. In the realistic simulation study, the NGS technique was used to rank reconstruction methods for quantitative single-photon emission computed tomography (SPECT) based on their performance on the task of estimating the mean activity concentration within a known volume of interest

11. A no-gold-standard technique for objective assessment of quantitative nuclear-medicine imaging methods

International Nuclear Information System (INIS)

Jha, Abhinav K; Frey, Eric C; Caffo, Brian

2016-01-01

The objective optimization and evaluation of nuclear-medicine quantitative imaging methods using patient data is highly desirable but often hindered by the lack of a gold standard. Previously, a regression-without-truth (RWT) approach has been proposed for evaluating quantitative imaging methods in the absence of a gold standard, but this approach implicitly assumes that bounds on the distribution of true values are known. Several quantitative imaging methods in nuclear-medicine imaging measure parameters where these bounds are not known, such as the activity concentration in an organ or the volume of a tumor. We extended upon the RWT approach to develop a no-gold-standard (NGS) technique for objectively evaluating such quantitative nuclear-medicine imaging methods with patient data in the absence of any ground truth. Using the parameters estimated with the NGS technique, a figure of merit, the noise-to-slope ratio (NSR), can be computed, which can rank the methods on the basis of precision. An issue with NGS evaluation techniques is the requirement of a large number of patient studies. To reduce this requirement, the proposed method explored the use of multiple quantitative measurements from the same patient, such as the activity concentration values from different organs in the same patient. The proposed technique was evaluated using rigorous numerical experiments and using data from realistic simulation studies. The numerical experiments demonstrated that the NSR was estimated accurately using the proposed NGS technique when the bounds on the distribution of true values were not precisely known, thus serving as a very reliable metric for ranking the methods on the basis of precision. In the realistic simulation study, the NGS technique was used to rank reconstruction methods for quantitative single-photon emission computed tomography (SPECT) based on their performance on the task of estimating the mean activity concentration within a known volume of interest

12. Quench correction in liquid scintillation counting by a combined internal standard-samples channels ratio technique

International Nuclear Information System (INIS)

Dahlberg, E.

1982-01-01

A well-known problem in liquid scintillation counting (LSC) is that radioactivity cannot be measured with 100% efficiency, e.g., due to ''quenching'', which thus needs be corrected for. Three methods (viz., those of internal standard (IS), samples channels ratio (SCR), and external standard channels ratio (ESCR) are in common use to accomplish quench correction. None of these methods is ideal. This paper shows that a combination of the IS and SCR methods (IS-SCR) ameliorates the major disadvantages of both techniques and the disadvantage of the SCR technique at low count rates have been eliminated in the IS-SCR method, which also has a low volume dependence compared to the IS and ESCR methods. The IS-SCR method is not affected by time-dependent diffusion of solutes and solvents into the walls of plastic counting vials, which is a major drawback of the ESCR technique. Used with a simple linear regression technique, the IS-SCR quench curves may be linearized over wide ranges of efficiencies. In view of the wide-spread application of LSC, the IS-SCR technique is therefore likely to be useful to many investigators. 2 figures, 2 tables

13. Assessment of Snared-Loop Technique When Standard Retrieval of Inferior Vena Cava Filters Fails

International Nuclear Information System (INIS)

Doody, Orla; Noe, Geertje; Given, Mark F.; Foley, Peter T.; Lyon, Stuart M.

2009-01-01

Purpose To identify the success and complications related to a variant technique used to retrieve inferior vena cava filters when simple snare approach has failed. Methods A retrospective review of all Cook Guenther Tulip filters and Cook Celect filters retrieved between July 2006 and February 2008 was performed. During this period, 130 filter retrievals were attempted. In 33 cases, the standard retrieval technique failed. Retrieval was subsequently attempted with our modified retrieval technique. Results The retrieval was successful in 23 cases (mean dwell time, 171.84 days; range, 5-505 days) and unsuccessful in 10 cases (mean dwell time, 162.2 days; range, 94-360 days). Our filter retrievability rates increased from 74.6% with the standard retrieval method to 92.3% when the snared-loop technique was used. Unsuccessful retrieval was due to significant endothelialization (n = 9) and caval penetration by the filter (n = 1). A single complication occurred in the group, in a patient developing pulmonary emboli after attempted retrieval. Conclusion The technique we describe increased the retrievability of the two filters studied. Hook endothelialization is the main factor resulting in failed retrieval and continues to be a limitation with these filters.

14. High performance liquid chromatographic determination of ...

African Journals Online (AJOL)

STORAGESEVER

2010-02-08

sulphonate (synthesized). Instrumentation. The chromatographic apparatus consisted of a Cecil 1200 series. 1000 high performance liquid chromatograph. The analytical column was ODS hypersil C18,5 µm particle size in 250 mm ...

15. Chromatographic separation of alkaline phosphatase from dental enamel

DEFF Research Database (Denmark)

Moe, D; Kirkeby, S; Salling, E

1989-01-01

Alkaline phosphatase (AP) was prepared from partly mineralized bovine enamel by extraction in phosphate buffer, centrifugation and various chromatographic techniques. Chromatofocusing showed that the enamel enzyme possessed five isoelectric points at the acid pH level ranging from pH 5.7 to pH 4...

16. Qualification of an Agilent Technologies 7890A gas chromatograph used in the biotechnology industry

International Nuclear Information System (INIS)

Alvarez Gonzalez, Alberto; Tambara Hernandez, Yanet; Alvarez Gil, Felix

2014-01-01

The drug manufacture is governed by strict international standards that guarantee reproducibility and consistency of results. The qualification of the instruments used in the productive processes, as well as in the characterization of products and their quality control are prerequisites to the validation of any analytical technique using them. One of the instrumental techniques used in the biotechnical industry is Gas Chromatography. A standard of pure caffeine was used for analysis in addition to a HP-5 30 m x 0,32 mm d.i. and 0,33 μm thick film column was used in a Gas Chromatograph coupled with a Flame Ionization Detector. For the testing of the different modules involved in the analysis (injector, column, oven and detector), an experimental design was made to estimate several parameters

17. Advanced Packaging Materials and Techniques for High Power TR Module: Standard Flight vs. Advanced Packaging

Science.gov (United States)

Hoffman, James Patrick; Del Castillo, Linda; Miller, Jennifer; Jenabi, Masud; Hunter, Donald; Birur, Gajanana

2011-01-01

The higher output power densities required of modern radar architectures, such as the proposed DESDynI [Deformation, Ecosystem Structure, and Dynamics of Ice] SAR [Synthetic Aperture Radar] Instrument (or DSI) require increasingly dense high power electronics. To enable these higher power densities, while maintaining or even improving hardware reliability, requires advances in integrating advanced thermal packaging technologies into radar transmit/receive (TR) modules. New materials and techniques have been studied and compared to standard technologies.

18. Extending and simplifying the standard Köhn-pipette technique for grain size analysis

Science.gov (United States)

Hirsch, Florian; Raab, Thomas

2014-05-01

Grain size distribution is a fundamental parameter to characterize physical properties of soils and sediments. Manifold approaches exist and according to the DIN ISO 11277 soil texture is analyzed by default with the combined pipette sieving and sedimentation method developed by Köhn. With this standard technique subfractions of sand and silt as well as the total clay content can be determined but the differentiation of clay subfractions is impossible. As the differentiation of the clay subfractions yields relevant information about pedogenesis, we present a protocol basing on standard techniques of granulometry with easy to handle and low cost equipment. The protocol was tested on a set of soil samples to cover the range of grain size distributions. We used a three-step procedure for achieving the grain size distribution of soil samples taking into account the subfractions of sand, silt and clay by a combination of sedimentation, centrifugal sedimentation and wet sieving. The pipetting was done with a piston-stroke pipette instead of the referred complex pipette from the DIN ISO 11277. Our first results show that the applied protocol is less prone to operating errors than the standard Köhn-pipette technique. Furthermore, even a less experienced laboratory worker can handle 10 samples in one day. Analyses of a luvisol profile, sampled in high spatial resolution, showed that the lessivation process is characterized by translocation of fine clay from the eluvial horizon to the illuvial horizon. Therefore our protocol is a fast alternative to detect lessivation, which is otherwise only clearly identifiable by micromorphological investigation and not by the standard Köhn-pipette technique.

19. Chemical characterization of Brickellia cavanillesii (Asteraceae) using gas chromatographic methods

OpenAIRE

Eshiet, Etetor R; Zhu, Jinqiu; Anderson, Todd A; Smith, Ernest E

2013-01-01

A methanol extract of lyophilized Brickellia cavanillesii was quantitatively analyzed using gas chromatographic (GC) techniques. The chromatographic methods employed were (i) GC-flame ionization detector (GC-FID), (ii) GC-mass spectrometry (GC-MS), and (iii) purge and trap GC-MS (P&T GC-MS). Thirteen compounds were identified with a quality match of 90% and above using GC-MS. The compounds were (1) Cyclohexene, 6-ethenyl-6-methyl-1-(1-methylethyl)-3-(1-methylethylidene)-, (S)-; (2) Bicylo (2....

20. Impact of Standardized Communication Techniques on Errors during Simulated Neonatal Resuscitation.

Science.gov (United States)

Yamada, Nicole K; Fuerch, Janene H; Halamek, Louis P

2016-03-01

Current patterns of communication in high-risk clinical situations, such as resuscitation, are imprecise and prone to error. We hypothesized that the use of standardized communication techniques would decrease the errors committed by resuscitation teams during neonatal resuscitation. In a prospective, single-blinded, matched pairs design with block randomization, 13 subjects performed as a lead resuscitator in two simulated complex neonatal resuscitations. Two nurses assisted each subject during the simulated resuscitation scenarios. In one scenario, the nurses used nonstandard communication; in the other, they used standardized communication techniques. The performance of the subjects was scored to determine errors committed (defined relative to the Neonatal Resuscitation Program algorithm), time to initiation of positive pressure ventilation (PPV), and time to initiation of chest compressions (CC). In scenarios in which subjects were exposed to standardized communication techniques, there was a trend toward decreased error rate, time to initiation of PPV, and time to initiation of CC. While not statistically significant, there was a 1.7-second improvement in time to initiation of PPV and a 7.9-second improvement in time to initiation of CC. Should these improvements in human performance be replicated in the care of real newborn infants, they could improve patient outcomes and enhance patient safety. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

1. Standard practice for monitoring atmospheric SO2 using the sulfation plate technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

1997-01-01

1.1 This practice covers a weighted average effective SO2 level for a 30-day interval through the use of the sulfation plate method, a technique for estimating the effective SO2 content of the atmosphere, and especially with regard to the atmospheric corrosion of stationary structures or panels. This practice is aimed at determining SO2 levels rather than sulfuric acid aerosol or acid precipitation. 1.2 The results of this practice correlate approximately with volumetric SO2 concentrations, although the presence of dew or condensed moisture tends to enhance the capture of SO2 into the plate. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Comparisons of neural networks to standard techniques for image classification and correlation

Science.gov (United States)

Paola, Justin D.; Schowengerdt, Robert A.

1994-01-01

Neural network techniques for multispectral image classification and spatial pattern detection are compared to the standard techniques of maximum-likelihood classification and spatial correlation. The neural network produced a more accurate classification than maximum-likelihood of a Landsat scene of Tucson, Arizona. Some of the errors in the maximum-likelihood classification are illustrated using decision region and class probability density plots. As expected, the main drawback to the neural network method is the long time required for the training stage. The network was trained using several different hidden layer sizes to optimize both the classification accuracy and training speed, and it was found that one node per class was optimal. The performance improved when 3x3 local windows of image data were entered into the net. This modification introduces texture into the classification without explicit calculation of a texture measure. Larger windows were successfully used for the detection of spatial features in Landsat and Magellan synthetic aperture radar imagery.

3. Radioimmunoassay of methaqualone in human urine compared with chromatographic methods

International Nuclear Information System (INIS)

Mule, S.J.; Kogan, M.; Jukofsky, D.

1978-01-01

The 125 I-radioimmunoassay for methaqualone in human urine was evaluated by a comparison with newly modified gas-liquid chromatographic and thin-layer chromatographic methods. The statistically significant sensitivity value for the radioimmunoassay was at 2 μg of methaqualone per liter of urine. The coefficient of variation was 2.88 -+ 0.16% intraassay. There was cross-reactivity only with metabolites of methaqualone, 4'-hydroxymethaqualone being twice as sensitively measured as methaqualone. There was complete agreement between results by radioimmunoassay and by gas-liquid chromatography in 96.7% of the samples analyzed. Only 1.2% of the radioimmunoassay values were false positives, and 2.1% false negatives (phi = 0.8917, P < 0.001). Comparisons between the thin-layer chromatographic data and the gas--liquid chromatographic or radioimmunoassay data showed less agreement because of the 50- to 200-fold higher sensitivity of the latter techniques. Gas--liquid chromatography therefore appears to represent the best reference method for the evaluation of the radioimmunoassay, which appears to be a very sensitive and reliable technique for detecting methaqualone and its metabolites in human urine

4. FTIR gas chromatographic analysis of perfumes

Science.gov (United States)

Diederich, H.; Stout, Phillip J.; Hill, Stephen L.; Krishnan, K.

1992-03-01

Perfumes, natural or synthetic, are complex mixtures consisting of numerous components. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques have been extensively utilized for the analysis of perfumes and essential oils. A limited number of perfume samples have also been analyzed by FT-IR gas chromatographic (GC-FTIR) techniques. Most of the latter studies have been performed using the conventional light pipe (LP) based GC-FTIR systems. In recent years, cold-trapping (in a matrix or neat) GC-FTIR systems have become available. The cold-trapping systems are capable of sub-nanogram sensitivities. In this paper, comparison data between the LP and the neat cold-trapping GC- FTIR systems is presented. The neat cold-trapping interface is known as Tracer. The results of GC-FTIR analysis of some commercial perfumes is also presented. For comparison of LP and Tracer GC-FTIR systems, a reference (synthetic) mixture containing 16 major and numerous minor constituents was used. The components of the mixture are the compounds commonly encountered in commercial perfumes. The GC-FTIR spectra of the reference mixture was obtained under identical chromatographic conditions from an LP and a Tracer system. A comparison of the two sets of data thus generated do indeed show the enhanced sensitivity level of the Tracer system. The comparison also shows that some of the major components detected by the Tracer system were absent from the LP data. Closer examination reveals that these compounds undergo thermal decomposition on contact with the hot gold surface that is part of the LP system. GC-FTIR data were obtained for three commercial perfume samples. The major components of these samples could easily be identified by spectra search against a digitized spectral library created using the Tracer data from the reference mixture.

5. Outcome of a standardized technique of preputial preservation surgery for phimosis: A single institutional experience

Directory of Open Access Journals (Sweden)

Kamalesh Pal

2014-01-01

Full Text Available Introduction: Pathological phimosis or preputial stenosis is a distressing problem in children leading to recurrent balanoposthitis, ballooning of prepuce, and rarely back pressure changes in the urinary tract. Circumcision has been the standard of care for such situations, although recently, various alternatives to circumcision have been reported in the literature. Most of these techniques are often complex and are met with poor acceptance. Moreover, besides personal preferences (in Hindus, advantages of preputial preservation is increasingly being realized recently. Materials and Methods: A prospective study was carried out in which a simple standardized technique of preputioplasty (dorsal slit was used in 40 pediatric preputial stenosis cases. The outcome of this procedure including cosmesis and parental satisfaction was evaluated. Results: The average duration of this procedure was from 10 to 25 min with no intraoperative complications. The cosmetic outcome was good in 62.5%, satisfactory in 30%, and poor in 7.5% of cases. All of the boys had retractable prepuce with no functional problems. There was 100% parental satisfaction. None of the patients required a redo procedure or circumcision. Conclusion: A dorsal slit of adequate length i.e.; 1/3 rd the length from the corona to the tip leads to a satisfactory cosmetic outcome in more than 92% of cases. Preputioplasty is a safe and simple alternative to more radical procedure of circumcision.

6. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques

Science.gov (United States)

Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

2014-01-01

On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent. PMID:25525356

7. Study of the standard direct costs of various techniques of advanced endoscopy. Comparison with surgical alternatives.

Science.gov (United States)

Loras, Carme; Mayor, Vicenç; Fernández-Bañares, Fernando; Esteve, Maria

2018-03-12

The complexity of endoscopy has carried out an increase in cost that has a direct effect on the healthcare systems. However, few studies have analyzed the cost of advanced endoscopic procedures (AEP). To carry out a calculation of the standard direct costs of AEP, and to make a financial comparison with their surgical alternatives. Calculation of the standard direct cost in carrying out each procedure. An endoscopist detailed the time, personnel, materials, consumables, recovery room time, stents, pathology and medication used. The cost of surgical procedures was the average cost recorded in the hospital. Thirty-eight AEP were analyzed. The technique showing lowest cost was gastroscopy + APC (€116.57), while that with greatest cost was ERCP with cholangioscopy + stent placement (€5083.65). Some 34.2% of the procedures registered average costs of €1000-2000. In 57% of cases, the endoscopic alternative was 2-5 times more cost-efficient than surgery, in 31% of cases indistinguishable or up to 1.4 times more costly. Standard direct cost of the majority of AEP is reported using a methodology that enables easy application in other centers. For the most part, endoscopic procedures are more cost-efficient than the corresponding surgical procedure. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

8. Closing the gap: accelerating the translational process in nanomedicine by proposing standardized characterization techniques.

Science.gov (United States)

Khorasani, Ali A; Weaver, James L; Salvador-Morales, Carolina

2014-01-01

On the cusp of widespread permeation of nanomedicine, academia, industry, and government have invested substantial financial resources in developing new ways to better treat diseases. Materials have unique physical and chemical properties at the nanoscale compared with their bulk or small-molecule analogs. These unique properties have been greatly advantageous in providing innovative solutions for medical treatments at the bench level. However, nanomedicine research has not yet fully permeated the clinical setting because of several limitations. Among these limitations are the lack of universal standards for characterizing nanomaterials and the limited knowledge that we possess regarding the interactions between nanomaterials and biological entities such as proteins. In this review, we report on recent developments in the characterization of nanomaterials as well as the newest information about the interactions between nanomaterials and proteins in the human body. We propose a standard set of techniques for universal characterization of nanomaterials. We also address relevant regulatory issues involved in the translational process for the development of drug molecules and drug delivery systems. Adherence and refinement of a universal standard in nanomaterial characterization as well as the acquisition of a deeper understanding of nanomaterials and proteins will likely accelerate the use of nanomedicine in common practice to a great extent.

9. Vibrational Spectroscopy of Chromatographic Interfaces

Energy Technology Data Exchange (ETDEWEB)

Jeanne E. Pemberton

2011-03-10

Chromatographic separations play a central role in DOE-supported fundamental research related to energy, biological systems, the environment, and nuclear science. The overall portfolio of research activities in the Separations and Analysis Program within the DOE Office of Basic Energy Sciences includes support for activities designed to develop a molecular-level understanding of the chemical processes that underlie separations for both large-scale and analytical-scale purposes. The research effort funded by this grant award was a continuation of DOE-supported research to develop vibrational spectroscopic methods to characterize the interfacial details of separations processes at a molecular level.

10. Open Partial Nephrectomy in Renal Cancer: A Feasible Gold Standard Technique in All Hospitals

Directory of Open Access Journals (Sweden)

J. M. Cozar

2008-01-01

Full Text Available Introduction. Partial nephrectomy (PN is playing an increasingly important role in localized renal cell carcinoma (RCC as a true alternative to radical nephrectomy. With the greater experience and expertise of surgical teams, it has become an alternative to radical nephrectomy in young patients when the tumor diameter is 4 cm or less in almost all hospitals since cancer-specific survival outcomes are similar to those obtained with radical nephrectomy. Materials and Methods. The authors comment on their own experience and review the literature, reporting current indications and outcomes including complications. The surgical technique of open partial nephrectomy is outlined. Conclusions. Nowadays, open PN is the gold standard technique to treat small renal masses, and all nonablative techniques must pass the test of time to be compared to PN. It is not ethical for patients to undergo radical surgery just because the urologists involved do not have adequate experience with PN. Patients should be involved in the final treatment decision and, when appropriate, referred to specialized centers with experience in open or laparoscopic partial nephrectomies.

11. Comparative analysis of photograph-based clinical goniometry to standard techniques.

Science.gov (United States)

2015-06-01

Assessment of joint range of motion (ROM) is an accepted evaluation of disability as well as an indicator of recovery from musculoskeletal injuries. Many goniometric techniques have been described to measure ROM, with variable validity due to inter-rater reliability. In this report, we assessed the validity of photograph-based goniometry in measurement of ROM and its inter-rater reliability and compared it to two other commonly used techniques. We examined three methods for measuring ROM in the upper extremity: manual goniometry (MG), visual estimations (VE), and photograph-based goniometry (PBG). Eight motions of the upper extremity were measured in 69 participants at an academic medical center. We found visual estimations and photograph-based goniometry to be clinically valid when tested against manual goniometry (r avg. 0.58, range 0.28 to 0.87). Photograph-based measurements afforded a satisfactory degree of inter-rater reliability (ICC avg. 0.77, range 0.28 to 0.96). Our study supports photograph-based goniometry as the new standard goniometric technique, as it has been clinically validated, is performed with greater consistency and better inter-rater reliability when compared with manual goniometry. It also allows for better documentation of measurements and potential incorporation into medical records in direct contrast to visual estimation.

12. MATLAB Toolboxes for Reference Electrode Standardization Technique (REST) of Scalp EEG.

Science.gov (United States)

Dong, Li; Li, Fali; Liu, Qiang; Wen, Xin; Lai, Yongxiu; Xu, Peng; Yao, Dezhong

2017-01-01

Reference electrode standardization technique (REST) has been increasingly acknowledged and applied as a re-reference technique to transform an actual multi-channels recordings to approximately zero reference ones in electroencephalography/event-related potentials (EEG/ERPs) community around the world in recent years. However, a more easy-to-use toolbox for re-referencing scalp EEG data to zero reference is still lacking. Here, we have therefore developed two open-source MATLAB toolboxes for REST of scalp EEG. One version of REST is closely integrated into EEGLAB, which is a popular MATLAB toolbox for processing the EEG data; and another is a batch version to make it more convenient and efficient for experienced users. Both of them are designed to provide an easy-to-use for novice researchers and flexibility for experienced researchers. All versions of the REST toolboxes can be freely downloaded at http://www.neuro.uestc.edu.cn/rest/Down.html, and the detailed information including publications, comments and documents on REST can also be found from this website. An example of usage is given with comparative results of REST and average reference. We hope these user-friendly REST toolboxes could make the relatively novel technique of REST easier to study, especially for applications in various EEG studies.

13. Determination of moisture content in steams and variation in moisture content with operating boiler level by analyzing sodium content in steam generator water and steam condensate of a nuclear power plant using ion chromatographic technique

International Nuclear Information System (INIS)

Pal, P.K.; Bohra, R.C.

2015-01-01

Dry steam with moisture content less than <1% is the stringent requirements in a steam generator for good health of the turbine. In order to confirm the same, determination of sodium is done in steam generator water and steam condensate using Flame photometer in ppm level and ion chromatograph in ppb level. Depending on the carry over of sodium in steam along with the water droplet (moisture), the moisture content in steam was calculated and was found to be < 1% which is requirements of the system. The paper described the salient features of a PHWR, principle of Ion Chromatography, chemistry parameters of Steam Generators and calculation of moisture content in steam on the basis of sodium analysis. (author)

14. Are neck nodal volumes drawn on CT slices covered by standard three-field technique?

Science.gov (United States)

Sanguineti, Giuseppe; Culp, Laura R; Endres, Eugene J; Bayouth, John E

2004-07-01

Several definitions have been proposed in the past few years on how to contour the various neck nodal levels on CT slices. However, whether the resulting nodal volumes would have been covered by standard techniques is unknown. The purpose of this study was to clarify this issue. Eight patients (N0-N1) with head-and-neck cancer from various primary sites referred to us for definitive radiotherapy were included in this study. Two observers contoured the level Ib-V neck nodal volumes on planning CT according to seven reported definitions. Each observer also drew blocks on digitally reconstructed radiographs for the initial (on-cord) phase of a standard three-field technique (parallel opposed lateral fields and AP supraclavicular field) for three different clinical settings: "medium" larynx (to cover upper, mid, and low jugular nodes), "big" larynx (same as for medium, plus posterior cervical nodes), and "tonsil" (same as for big plus retropharyngeal nodes). Fields blocks were concentrically reduced 5 mm in all directions as a surrogate for the clinical target volume to planning target volume expansion. A plan was created for each of the clinical settings, delivering 2 Gy to the International Commission on Radiation Units and Measurements reference point. The coverage of the nodal levels according to the various definitions was investigated throughout the analysis of the volume receiving 50%, 80%, and 95% of the prescribed dose (V(50), V(80), and V(95), respectively) and dose covering at least 95% of the volume (D(95)) values extracted from their cumulative dose-volume histograms in the three clinical settings. The V(50) coverage of levels III and IV was adequate for all definitions and trials. For level V, about 3-5% of the volume was outside the 50% isodose of those trials that targeted the posterior cervical chain. Coverage of level Ib was highly dependent on the definition, with up to 21% of the volume outside the standard tonsillar fields. For level II, although

15. A standardized infrared imaging technique that specifically detects UCP1-mediated thermogenesis in vivo.

Science.gov (United States)

Crane, Justin D; Mottillo, Emilio P; Farncombe, Troy H; Morrison, Katherine M; Steinberg, Gregory R

2014-07-01

The activation and expansion of brown adipose tissue (BAT) has emerged as a promising strategy to counter obesity and the metabolic syndrome by increasing energy expenditure. The subsequent testing and validation of novel agents that augment BAT necessitates accurate pre-clinical measurements in rodents regarding the capacity for BAT-derived thermogenesis. We present a novel method to measure BAT thermogenesis using infrared imaging following β3-adrenoreceptor stimulation in mice. We show that the increased body surface temperature observed using this method is due solely to uncoupling protein-1 (UCP1)-mediated thermogenesis and that this technique is able to discern differences in BAT activity in mice acclimated to 23 °C or thermoneutrality (30 °C). These findings represent the first standardized method utilizing infrared imaging to specifically detect UCP1 activity in vivo.

16. Standardization of Berberis aristata extract through conventional and modern HPTLC techniques

Directory of Open Access Journals (Sweden)

Dinesh K. Patel

2012-05-01

Full Text Available Objective: Berberis aristata (Berberidaceae is an important medicinal plant, found in the different region of the world. It has significant medicinal value in the traditional Indian and Chinese system of medicine. The aim of the present investigation includes qualitative and quantitative analysis of Berberis aristata extract. Methods: Present study includes determination of phytochemical analysis, solubility test, heavy metal analysis, antimicrobial study and quantitative analysis by HPTLC method. Results: Preliminary phytochemical analysis showed the presence of carbohydrate, glycoside, alkaloid, protein, amino acid, saponin, tannin and flavonoid. Solubility in water and alcohal were found to be 81.90% in water and 84.52% in 50% in alcohal. Loss on drying was found to be 5.32%. Total phenol and flavonoid content were found to be 0.11% and 2.8%. Level of lead, arsenic, mercury and cadmium complies the standard level. E. coli and salmonella was found to be absent whereas total bacterial count, yeast and moulds contents were found to be under the limit. Content of berberine was found to be 13.47% through HPTLC techniques. Conclusions: The results obtained from the present studies could be used as source of valuable information which can play an important role for the food scientists, researchers and even the consumers for its standards.

17. A standardized technique for high-pressure cooling of protein crystals.

Science.gov (United States)

Quirnheim Pais, David; Rathmann, Barbara; Koepke, Juergen; Tomova, Cveta; Wurzinger, Paul; Thielmann, Yvonne

2017-12-01

Cryogenic temperatures slow down secondary radiation damage during data collection from macromolecular crystals. In 1973, cooling at high pressure was identified as a method for cryopreserving crystals in their mother liquor [Thomanek et al. (1973). Acta Cryst. A29, 263-265]. Results from different groups studying different crystal systems indicated that the approach had merit, although difficulties in making the process work have limited its widespread use. Therefore, a simplified and reliable technique has been developed termed high-pressure cooling (HPC). An essential requirement for HPC is to protect crystals in capillaries. These capillaries form part of new sample holders with SPINE standard dimensions. Crystals are harvested with the capillary, cooled at high pressure (220 MPa) and stored in a cryovial. This system also allows the usage of the standard automation at the synchrotron. Crystals of hen egg-white lysozyme and concanavalin A have been successfully cryopreserved and yielded data sets to resolutions of 1.45 and 1.35 Å, respectively. Extensive work has been performed to define the useful working range of HPC in capillaries with 250 µm inner diameter. Three different 96-well crystallization screens that are most frequently used in our crystallization facility were chosen to study the formation of amorphous ice in this cooling setup. More than 89% of the screening solutions were directly suitable for HPC. This achievement represents a drastic improvement for crystals that suffered from cryoprotection or were not previously eligible for cryoprotection.

18. Dosimetric comparison of intensity modulated radiotherapy techniques and standard wedged tangents for whole breast radiotherapy

International Nuclear Information System (INIS)

Fong, Andrew; Bromley, Regina; Beat, Mardi; Vien, Din; Dineley, Jude; Morgan, Graeme

2009-01-01

Full text: Prior to introducing intensity modulated radiotherapy (IMRT) for whole breast radiotherapy (WBRT) into our department we undertook a comparison of the dose parameters of several IMRT techniques and standard wedged tangents (SWT). Our aim was to improve the dose distribution to the breast and to decrease the dose to organs at risk (OAR): heart, lung and contralateral breast (Contra Br). Treatment plans for 20 women (10 right-sided and 10 left-sided) previously treated with SWT for WBRT were used to compare (a) SWT; (b) electronic compensators IMRT (E-IMRT); (c) tangential beam IMRT (T-IMRT); (d) coplanar multi-field IMRT (CP-IMRT); and (e) non-coplanar multi-field IMRT (NCP-IMRT). Plans for the breast were compared for (i) dose homogeneity (DH); (ii) conformity index (CI); (iii) mean dose; (iv) maximum dose; (v) minimum dose; and dose to OAR were calculated (vi) heart; (vii) lung and (viii) Contra Br. Compared with SWT, all plans except CP-IMRT gave improvement in at least two of the seven parameters evaluated. T-IMRT and NCP-IMRT resulted in significant improvement in all parameters except DH and both gave significant reduction in doses to OAR. As on initial evaluation NCP-IMRT is likely to be too time consuming to introduce on a large scale, T-IMRT is the preferred technique for WBRT for use in our department.

19. Cost minimisation analysis of using acellular dermal matrix (Strattice™) for breast reconstruction compared with standard techniques.

Science.gov (United States)

Johnson, R K; Wright, C K; Gandhi, A; Charny, M C; Barr, L

2013-03-01

We performed a cost analysis (using UK 2011/12 NHS tariffs as a proxy for cost) comparing immediate breast reconstruction using the new one-stage technique of acellular dermal matrix (Strattice™) with implant versus the standard alternative techniques of tissue expander (TE)/implant as a two-stage procedure and latissimus dorsi (LD) flap reconstruction. Clinical report data were collected for operative time, length of stay, outpatient procedures, and number of elective and emergency admissions in our first consecutive 24 patients undergoing one-stage Strattice reconstruction. Total cost to the NHS based on tariff, assuming top-up payments to cover Strattice acquisition costs, was assessed and compared to the two historical control groups matched on key variables. Eleven patients having unilateral Strattice reconstruction were compared to 10 having TE/implant reconstruction and 10 having LD flap and implant reconstruction. Thirteen patients having bilateral Strattice reconstruction were compared to 12 having bilateral TE/implant reconstruction. Total costs were: unilateral Strattice, £3685; unilateral TE, £4985; unilateral LD and implant, £6321; bilateral TE, £5478; and bilateral Strattice, £6771. The cost analysis shows a financial advantage of using acellular dermal matrix (Strattice) in unilateral breast reconstruction versus alternative procedures. The reimbursement system in England (Payment by Results) is based on disease-related groups similar to that of many countries across Europe and tariffs are based on reported hospital costs, making this analysis of relevance in other countries. Copyright © 2013 Elsevier Ltd. All rights reserved.

20. A Critical Appraisal of Techniques, Software Packages, and Standards for Quantitative Proteomic Analysis

Science.gov (United States)

Lawless, Craig; Hubbard, Simon J.; Fan, Jun; Bessant, Conrad; Hermjakob, Henning; Jones, Andrew R.

2012-01-01

Abstract New methods for performing quantitative proteome analyses based on differential labeling protocols or label-free techniques are reported in the literature on an almost monthly basis. In parallel, a correspondingly vast number of software tools for the analysis of quantitative proteomics data has also been described in the literature and produced by private companies. In this article we focus on the review of some of the most popular techniques in the field and present a critical appraisal of several software packages available to process and analyze the data produced. We also describe the importance of community standards to support the wide range of software, which may assist researchers in the analysis of data using different platforms and protocols. It is intended that this review will serve bench scientists both as a useful reference and a guide to the selection and use of different pipelines to perform quantitative proteomics data analysis. We have produced a web-based tool (http://www.proteosuite.org/?q=other_resources) to help researchers find appropriate software for their local instrumentation, available file formats, and quantitative methodology. PMID:22804616

1. Flow Diversion versus Standard Endovascular Techniques for the Treatment of Unruptured Carotid-Ophthalmic Aneurysms.

Science.gov (United States)

Di Maria, F; Pistocchi, S; Clarençon, F; Bartolini, B; Blanc, R; Biondi, A; Redjem, H; Chiras, J; Sourour, N; Piotin, M

2015-12-01

Over the past few years, flow diversion has been increasingly adopted for the treatment of intracranial aneurysms, especially in the paraclinoid and paraophthalmic carotid segment. We compared clinical and angiographic outcomes and complication rates in 2 groups of patients with unruptured carotid-ophthalmic aneurysms treated for 7 years by either standard coil-based techniques or flow diversion. From February 2006 to December 2013, 162 unruptured carotid-ophthalmic aneurysms were treated endovascularly in 138 patients. Sixty-seven aneurysms were treated by coil-based techniques in 61 patients. Flow diverters were deployed in 95 unruptured aneurysms (77 patients), with additional coiling in 27 patients. Complication rates, clinical outcome, and immediate and long-term angiographic results were retrospectively analyzed. No procedure-related deaths occurred. Four procedure-related thromboembolic events (6.6%) leading to permanent morbidity in 1 case (1.6%) occurred in the coiling group. Neurologic complications were observed in 6 patients (7.8%) in the flow-diversion group, resulting in 3.9% permanent morbidity. No statistically significant difference was found between complication (P = .9) and morbidity rates (P = .6). In the coiling group (median follow-up, 31.5 ± 24.5 months), recanalization occurred at 1 year in 23/50 (54%) aneurysms and 27/55 aneurysms (50.9%) at the latest follow-up, leading to retreatment in 6 patients (9%). In the flow-diversion group (mean follow-up, 13.5 ± 10.8 months), 85.3% (35/41) of all aneurysms were occluded after 12 months, and 74.6% (50/67) on latest follow-up. The retreatment rate was 2.1%. Occlusion rates between the 2 groups differed significantly at 12 months (P < .001) and at the latest follow-up (P < .005). Our retrospective analysis shows better long-term occlusion of carotid-ophthalmic aneurysms after use of flow diverters compared with standard coil-based techniques, without significant differences in permanent morbidity

2. The “excluding” suture technique for surgical closure of ventricular septal defects: A retrospective study comparing the standard technique

Directory of Open Access Journals (Sweden)

Roy Varghese

2016-01-01

Conclusion: Surgical closure of VSDs can be accomplished by placing sutures along the margins or away with comparable results. The incidence of CHB, however, seems to be less when the “excluding” technique is employed.

3. Reduced Rate of Dehiscence After Implementation of a Standardized Fascial Closure Technique in Patients Undergoing Emergency Laparotomy

DEFF Research Database (Denmark)

Tolstrup, Mai-Britt; Watt, Sara Kehlet; Gögenur, Ismail

2017-01-01

is lacking. We aimed to investigate whether this technique would reduce the rate of dehiscence. METHODS: A standardized procedure of closing the midline laparotomy by using a "small steps" technique of continuous suturing with a slowly absorbable (polydioxanone) suture material in a wound-suture ratio...

4. [Abdominothoracic esophageal resection according to Ivor Lewis with intrathoracic anastomosis : standardized totally minimally invasive technique].

Science.gov (United States)

Runkel, N; Walz, M; Ketelhut, M

2015-05-01

The clinical and scientific interest in minimally invasive techniques for esophagectomy (MIE) are increasing; however, the intrathoracic esophagogastric anastomosis remains a surgical challenge and lacks standardization. Surgeons either transpose the anastomosis to the cervical region or perform hybrid thoracotomy for stapler access. This article reports technical details and early experiences with a completely laparoscopic-thoracoscopic approach for Ivor Lewis esophagectomy without additional thoracotomy. The extent of radical dissection follows clinical guidelines. Laparoscopy is performed with the patient in a beach chair position and thoracoscopy in a left lateral decubitus position using single lung ventilation. The anvil of the circular stapler is placed transorally into the esophageal stump. The specimen and gastric conduit are exteriorized through a subcostal rectus muscle split incision. The stapler body is placed into the gastric conduit and both are advanced through the abdominal mini-incision transhiatally into the right thoracic cavity, where the anastomosis is constructed. Data were collected prospectively and analyzed retrospectively. A total of 23 non-selected consecutive patients (mean age 69 years, range 46-80 years) with adenocarcinoma (n = 19) or squamous cell carcinoma (n = 4) were surgically treated between June 2010 and July 2013. Neoadjuvant therapy was performed in 15 patients resulting in 10 partial and 4 complete remissions. There were no technical complications and no conversions. Mean operative time was 305 min (range 220-441 min). The median lymph node count was 16 (range 4-42). An R0 resection was achieved in 91 % of patients and 3 anastomotic leaks occurred which were successfully managed endoscopically. There were no postoperative deaths. The intrathoracic esophagogastric anastomosis during minimally invasive Ivor Lewis esophagectomy can be constructed in a standardized fashion without an additional thoracotomy

5. Multivariate analysis of chromatographic retention data as a supplementary means for grouping structurally related compounds.

Science.gov (United States)

Fasoula, S; Zisi, Ch; Sampsonidis, I; Virgiliou, Ch; Theodoridis, G; Gika, H; Nikitas, P; Pappa-Louisi, A

2015-03-27

In the present study a series of 45 metabolite standards belonging to four chemically similar metabolite classes (sugars, amino acids, nucleosides and nucleobases, and amines) was subjected to LC analysis on three HILIC columns under 21 different gradient conditions with the aim to explore whether the retention properties of these analytes are determined from the chemical group they belong. Two multivariate techniques, principal component analysis (PCA) and discriminant analysis (DA), were used for statistical evaluation of the chromatographic data and extraction similarities between chemically related compounds. The total variance explained by the first two principal components of PCA was found to be about 98%, whereas both statistical analyses indicated that all analytes are successfully grouped in four clusters of chemical structure based on the retention obtained in four or at least three chromatographic runs, which, however should be performed on two different HILIC columns. Moreover, leave-one-out cross-validation of the above retention data set showed that the chemical group in which an analyte belongs can be 95.6% correctly predicted when the analyte is subjected to LC analysis under the same four or three experimental conditions as the all set of analytes was run beforehand. That, in turn, may assist with disambiguation of analyte identification in complex biological extracts. Copyright © 2015 Elsevier B.V. All rights reserved.

6. Standardization of MIP technique in three-dimensional CT portography: usefulness in evaluation of portosystemic collaterals in cirrhotic patients

International Nuclear Information System (INIS)

Kim, Jong Gi; Kim, Yong; Kim, Chang Won; Lee, Jun Woo; Lee, Suk Hong

2003-01-01

To assess the usefulness of three-dimensional CT portography using a standardized maximum intensity projection (MIP) technique for the evaluation of portosystemic collaterals in cirrhotic patients. In 25 cirrhotic patients with portosystemic collaterals, three-phase CT using a multide-tector-row helical CT scanner was performed to evaluate liver disease. Late arterial-phase images were transferred to an Advantage Windows 3.1 workstation (Gener Electric). Axial images were reconstructed by means of three-dimensional CT portography, using both a standardized and a non-standardized MIP technique, and the respective reconstruction times were determined. Three-dimensional CT portography with the standardized technique involved eight planes, namely the spleno-portal confluence axis (coronal, lordotic coronal, lordotic coronal RAO 30 .deg. C, and lordotic coronal LAO 30 .deg. C), the left renal vein axis (lordotic coronal), and axial MIP images (lower esophagus level, gastric fundus level and splenic hilum). The eight MIP images obtained in each case were interpreted by two radiologists, who reached a consensus in their evaluation. The portosystemic collaterals evaluated were as follows: left gastric vein dilatation; esophageal, paraesophageal, gastric, and splenic varix; paraumbilical vein dilatation; gastro-renal, spleno-renal, and gastro-spleno-renal shunt; mesenteric, retroperitoneal, and omental collaterals. The average reconstruction time using the non-standardized MIP technique was 11 minutes 23 seconds, and with the standardized technique, the time was 6 minutes 5 seconds. Three-dimensional CT portography with the standardized technique demonstrated left gastric vein dilatation (n=25), esophageal varix (n=18), paraesophageal varix (n=13), gastric varix (n=4), splenic varix (n=4), paraumbilical vein dilatation (n=4), gastro-renal shunt (n=3), spleno-renal shunt (n=3), and gastro-spleno-renal shunt (n=1). Using three-dimensional CT protography and the non-standardized

7. Alternative chromatographic system for the quality control of lipophilic technetium-99m radiopharmaceuticals such as [99mTc(MIBI6]+

Directory of Open Access Journals (Sweden)

D.P. Faria

2015-01-01

Full Text Available Knowledge of the radiochemical purity of radiopharmaceuticals is mandatory and can be evaluated by several methods and techniques. Planar chromatography is the technique normally employed in nuclear medicine since it is simple, rapid and usually of low cost. There is no standard system for the chromatographic technique, but price, separation efficiency and short time for execution must be considered. We have studied an alternative system using common chromatographic stationary phase and alcohol or alcohol:chloroform mixtures as the mobile phase, using the lipophilic radiopharmaceutical [99mTc(MIBI6]+ as a model. Whatman 1 modified phase paper and absolute ethanol, Whatman 1 paper and methanol:chloroform (25:75, Whatman 3MM paper and ethanol:chloroform (25:75, and the more expensive ITLC-SG and 1-propanol:chloroform (10:90 were suitable systems for the direct determination of radiochemical purity of [99mTc(MIBI6]+ since impurities such as 99mTc-reduced-hydrolyzed (RH, 99mTcO4 - and [99mTc(cysteine2]- complex were completely separated from the radiopharmaceutical, which moved toward the front of chromatographic systems while impurities were retained at the origin. The time required for analysis was 4 to 15 min, which is appropriate for nuclear medicine routines.

8. Alternative chromatographic system for the quality control of lipophilic technetium-99m radiopharmaceuticals such as [{sup 99m}Tc(MIBI){sub 6}]{sup +}

Energy Technology Data Exchange (ETDEWEB)

Faria, D.P.; Buchpiguel, C.A.; Marques, F.L.N., E-mail: danielefaria1@gmail.com [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Departamento de Radiologia. Servico de Medicina Nuclear

2015-10-15

Knowledge of the radiochemical purity of radiopharmaceuticals is mandatory and can be evaluated by several methods and techniques. Planar chromatography is the technique normally employed in nuclear medicine since it is simple, rapid and usually of low cost. There is no standard system for the chromatographic technique, but price, separation efficiency and short time for execution must be considered. We have studied an alternative system using common chromatographic stationary phase and alcohol or alcohol:chloroform mixtures as the mobile phase, using the lipophilic radiopharmaceutical [{sup 99m}Tc(MIBI){sub 6}]{sup +} as a model. Whatman 1 modified phase paper and absolute ethanol, Whatman 1 paper and methanol: chloroform (25:75), Whatman 3MM paper and ethanol:chloroform (25:75), and the more expensive ITLC-SG and 1-propanol: chloroform (10:90) were suitable systems for the direct determination of radiochemical purity of [{sup 99m}Tc(MIBI){sub 6}]{sup +} since impurities such as {sup 99m}Tc-reduced-hydrolyzed (RH), {sup 99m}TcO4{sup -} and [{sup 99m}Tc(cysteine){sub 2}]{sup -} complex were completely separated from the radiopharmaceutical, which moved toward the front of chromatographic systems while impurities were retained at the origin. The time required for analysis was 4 to 15 min, which is appropriate for nuclear medicine routines. (author)

9. Development, improvement and calibration of neutronic reaction rates measurements: elaboration of a standard techniques basis

International Nuclear Information System (INIS)

Hudelot, J.P.

1998-06-01

In order to improve and to validate the neutronics calculation schemes, perfecting integral measurements of neutronics parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronics reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO 2 ) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of 238 U (defined as the ratio of 238 U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for 242 Pu (on MOX rods) and 232 Th (on

10. Standardization of pulmonary ventilation technique using volume-controlled ventilators in rats with congenital diaphragmatic hernia

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Rodrigo Melo Gallindo

Full Text Available OBJECTIVE: To standardize a technique for ventilating rat fetuses with Congenital Diaphragmatic Hernia (CDH using a volume-controlled ventilator. METHODS: Pregnant rats were divided into the following groups: a control (C; b exposed to nitrofen with CDH (CDH; and c exposed to nitrofen without CDH (N-. Fetuses of the three groups were randomly divided into the subgroups ventilated (V and non-ventilated (N-V. Fetuses were collected on day 21.5 of gestation, weighed and ventilated for 30 minutes using a volume-controlled ventilator. Then the lungs were collected for histological study. We evaluated: body weight (BW, total lung weight (TLW, left lung weight (LLW, ratios TLW / BW and LLW / BW, morphological histology of the airways and causes of failures of ventilation. RESULTS: BW, TLW, LLW, TLW / BW and LLW / BW were higher in C compared with N- (p 0.05. The morphology of the pulmonary airways showed hypoplasia in groups N- and CDH, with no difference between V and N-V (p <0.05. The C and N- groups could be successfully ventilated using a tidal volume of 75 ìl, but the failure of ventilation in the CDH group decreased only when ventilated with 50 ìl. CONCLUSION: Volume ventilation is possible in rats with CDH for a short period and does not alter fetal or lung morphology.

11. Modeling Aquatic Toxicity through Chromatographic Systems.

Science.gov (United States)

Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí

2017-08-01

Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

12. Modification of the cranial closing wedge ostectomy technique for the treatment of canine cruciate disease. Description and comparison with standard technique.

Science.gov (United States)

Wallace, A M; Addison, E S; Smith, B A; Radke, H; Hobbs, S J

2011-01-01

To describe a modification of the cranial closing wedge ostectomy (CCWO) technique and to compare its efficacy to the standard technique on cadaveric specimens. The standard and modified CCWO technique were applied to eight pairs of cadaveric tibiae. The following parameters were compared following the ostectomy: degrees of plateau levelling achieved (degrees), tibial long axis shift (degrees), reduction in tibial length (mm), area of bone wedge removed (cm²), and the area of proximal fragment (cm²). The size of the removed wedge of bone and the reduction in tibial length were significantly less with the modified CCWO technique. The modified CCWO has two main advantages. Firstly a smaller wedge is removed, allowing a greater preservation of bone stock in the proximal tibia, which is advantageous for implant placement. Secondly, the tibia is shortened to a lesser degree, which might reduce the risk of recurvatum, fibular fracture and patella desmitis. These factors are particularly propitious for the application of this technique to Terrier breeds with excessive tibial plateau angle, where large angular corrections are required. The modified CCWO is equally effective for plateau levelling and results in an equivalent tibial long-axis shift. A disadvantage with the modified technique is that not all of the cross sectional area of the distal fragment contributes to load sharing at the osteotomy.

13. Chromatographic analysis of tryptophan metabolites.

Science.gov (United States)

Sadok, Ilona; Gamian, Andrzej; Staniszewska, Magdalena Maria

2017-08-01

The kynurenine pathway generates multiple tryptophan metabolites called collectively kynurenines and leads to formation of the enzyme cofactor nicotinamide adenine dinucleotide. The first step in this pathway is tryptophan degradation, initiated by the rate-limiting enzymes indoleamine 2,3-dioxygenase, or tryptophan 2,3-dioxygenase, depending on the tissue. The balanced kynurenine metabolism, which has been a subject of multiple studies in last decades, plays an important role in several physiological and pathological conditions such as infections, autoimmunity, neurological disorders, cancer, cataracts, as well as pregnancy. Understanding the regulation of tryptophan depletion provide novel diagnostic and treatment opportunities, however it requires reliable methods for quantification of kynurenines in biological samples with complex composition (body fluids, tissues, or cells). Trace concentrations, interference of sample components, and instability of some tryptophan metabolites need to be addressed using analytical methods. The novel separation approaches and optimized extraction protocols help to overcome difficulties in analyzing kynurenines within the complex tissue material. Recent developments in chromatography coupled with mass spectrometry provide new opportunity for quantification of tryptophan and its degradation products in various biological samples. In this review, we present current accomplishments in the chromatographic methodologies proposed for detection of tryptophan metabolites and provide a guide for choosing the optimal approach. © 2017 The Authors. Journal of Separation Science published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

14. Standardization of the PCR technique for the detection of delta toxin in Staphylococcus spp.

Directory of Open Access Journals (Sweden)

C. Marconi

2005-06-01

Full Text Available Coagulase-negative staphylococci (CNS, components of the normal flora of neonates, have emerged as important opportunistic pathogens of nosocomial infections that occur in neonatal intensive care units. Some authors have reported the ability of some CNS strains, particularly Staphylococcus epidermidis, to produce a toxin similar to S. aureus delta toxin. This toxin is an exoprotein that has a detergent action on the membranes of various cell types resulting in rapid cell lysis. The objectives of the present study were to standardize the Polymerase Chain Reaction (PCR technique for the detection of the gene responsible for the production of delta toxin (hld gene in staphylococcal species isolated from catheters and blood cultures obtained from neonates, and to compare the results to those obtained with the phenotypic synergistic hemolysis method. Detection of delta toxin by the phenotypic and genotypic method yielded similar results for the S. aureus isolates. However, in S. epidermidis, a higher positivity was observed for PCR (97.4% compared to the synergistic hemolysis method (86.8%. Among CNS, S. epidermidis was the most frequent isolate and was a delta toxin producer. Staphylococcus simulans and S. warneri tested positive by the phenotypic method, but their positivity was not confirmed by PCR for the hld gene detection. These results indicate that different genes might be responsible for the production of this toxin in different CNS species, requiring highly specific primers for their detection. PCR was found to be a rapid and reliable method for the detection of the hld gene in S. aureus and S. epidermidis.

15. Characterization of lysozyme adsorption in cellulosic chromatographic materials using small-angle neutron scattering.

Science.gov (United States)

Koshari, Stijn H S; Wagner, Norman J; Lenhoff, Abraham M

2015-06-19

16. "Heidelberg standard examination" and "Heidelberg standard procedures" - Development of faculty-wide standards for physical examination techniques and clinical procedures in undergraduate medical education.

Science.gov (United States)

Nikendei, C; Ganschow, P; Groener, J B; Huwendiek, S; Köchel, A; Köhl-Hackert, N; Pjontek, R; Rodrian, J; Scheibe, F; Stadler, A-K; Steiner, T; Stiepak, J; Tabatabai, J; Utz, A; Kadmon, M

2016-01-01

The competent physical examination of patients and the safe and professional implementation of clinical procedures constitute essential components of medical practice in nearly all areas of medicine. The central objective of the projects "Heidelberg standard examination" and "Heidelberg standard procedures", which were initiated by students, was to establish uniform interdisciplinary standards for physical examination and clinical procedures, and to distribute them in coordination with all clinical disciplines at the Heidelberg University Hospital. The presented project report illuminates the background of the initiative and its methodological implementation. Moreover, it describes the multimedia documentation in the form of pocketbooks and a multimedia internet-based platform, as well as the integration into the curriculum. The project presentation aims to provide orientation and action guidelines to facilitate similar processes in other faculties.

17. Comparison of anthropometry with photogrammetry based on a standardized clinical photographic technique using a cephalostat and chair.

Science.gov (United States)

Han, Kihwan; Kwon, Hyuk Joon; Choi, Tae Hyun; Kim, Jun Hyung; Son, Daegu

2010-03-01

The aim of this study was to standardize clinical photogrammetric techniques, and to compare anthropometry with photogrammetry. To standardize clinical photography, we have developed a photographic cephalostat and chair. We investigated the repeatability of the standardized clinical photogrammetric technique. Then, with 40 landmarks, a total of 96 anthropometric measurement items was obtained from 100 Koreans. Ninety six photogrammetric measurements from the same subjects were also obtained from standardized clinical photographs using Adobe Photoshop version 7.0 (Adobe Systems Corporation, San Jose, CA, USA). The photogrammetric and anthropometric measurement data (mm, degree) were then compared. A coefficient was obtained by dividing the anthropometric measurements by the photogrammetric measurements. The repeatability of the standardized photography was statistically significantly high (p=0.463). Among the 96 measurement items, 44 items were reliable; for these items the photogrammetric measurements were not different to the anthropometric measurements. The remaining 52 items must be classified as unreliable. By developing a photographic cephalostat and chair, we have standardized clinical photogrammetric techniques. The reliable set of measurement items can be used as anthropometric measurements. For unreliable measurement items, applying a suitable coefficient to the photogrammetric measurement allows the anthropometric measurement to be obtained indirectly.

18. Development of Chromatographic Fingerprints of Eurycoma longifolia (Tongkat Ali Roots Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC

Directory of Open Access Journals (Sweden)

Nor Nasriah Zaini

2016-04-01

Full Text Available E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL−1 (r2 = 0.997 with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules. Selected chemometric techniques: cluster analysis (CA, discriminant analysis (DA, and principal component analysis (PCA were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.

19. Development of Chromatographic Fingerprints of Eurycoma longifolia (Tongkat Ali) Roots Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC).

Science.gov (United States)

Zaini, Nor Nasriah; Osman, Rozita; Juahir, Hafizan; Saim, Norashikin

2016-04-30

E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB) and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE) technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL(-1) (r² = 0.997) with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules). Selected chemometric techniques: cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.

20. Standard Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 The purpose of this test method is to define a general procedure for determining an unknown thermal-neutron fluence rate by neutron activation techniques. It is not practicable to describe completely a technique applicable to the large number of experimental situations that require the measurement of a thermal-neutron fluence rate. Therefore, this method is presented so that the user may adapt to his particular situation the fundamental procedures of the following techniques. 1.1.1 Radiometric counting technique using pure cobalt, pure gold, pure indium, cobalt-aluminum, alloy, gold-aluminum alloy, or indium-aluminum alloy. 1.1.2 Standard comparison technique using pure gold, or gold-aluminum alloy, and 1.1.3 Secondary standard comparison techniques using pure indium, indium-aluminum alloy, pure dysprosium, or dysprosium-aluminum alloy. 1.2 The techniques presented are limited to measurements at room temperatures. However, special problems when making thermal-neutron fluence rate measurements in high-...

1. [Health protection for rural workers: the need to standardize techniques for quantifying dermal exposure to pesticides].

Science.gov (United States)

Selmi, Giuliana da Fontoura Rodrigues; Trapé, Angelo Zanaga

2014-05-01

Quantification of dermal exposure to pesticides in rural workers, used in risk assessment, can be performed with different techniques such as patches or whole body evaluation. However, the wide variety of methods can jeopardize the process by producing disparate results, depending on the principles in sample collection. A critical review was thus performed on the main techniques for quantifying dermal exposure, calling attention to this issue and the need to establish a single methodology for quantification of dermal exposure in rural workers. Such harmonization of different techniques should help achieve safer and healthier working conditions. Techniques that can provide reliable exposure data are an essential first step towards avoiding harm to workers' health.

2. Standard techniques for presentation and analysis of crater size-frequency data. [on moon and planetary surfaces

Science.gov (United States)

Arvidson, R.; Boyce, J.; Chapman, C.; Cintala, M.; Fulchignoni, M.; Moore, H.; Soderblom, L.; Neukum, G.; Schultz, P.; Strom, R.

1979-01-01

In September 1977 a crater studies workshop was held for the purpose of developing standardized data analysis and presentation techniques. The present report contains the unanimous recommendations of the participants. Recommendations are devoted primarily to crater size-frequency data and refer to cumulative and relative size-frequency distribution plots and to morphological analysis.

3. Does leaf chemistry differentially affect breakdown in tropical vs temperate streams? Importance of standardized analytical techniques to measure leaf chemistry

Science.gov (United States)

Marcelo Ard& #243; n; Catherine M. Pringle; Susan L. Eggert

2009-01-01

Comparisons of the effects of leaf litter chemistry on leaf breakdown rates in tropical vs temperate streams are hindered by incompatibility among studies and across sites of analytical methods used to measure leaf chemistry. We used standardized analytical techniques to measure chemistry and breakdown rate of leaves from common riparian tree species at 2 sites, 1...

4. Portable optical frequency standard based on sealed gas-filled hollow-core fiber using a novel encapsulation technique

DEFF Research Database (Denmark)

Triches, Marco; Brusch, Anders; Hald, Jan

2015-01-01

A portable stand-alone optical frequency standard based on a gas-filled hollow-core photonic crystal fiber is developed to stabilize a fiber laser to the 13C2H2 P(16) (ν1 + ν3) transition at 1542 nm using saturated absorption. A novel encapsulation technique is developed to permanently seal...

5. [Comparison study on polymerase chain reaction (PCR) and standard culture technique in detecting mycobacterium tuberculosis to diagnose of joint tuberculosis].

Science.gov (United States)

Sun, Yong-sheng; Wen, Jian-min; Lü, Wei-xin; Lou, Si-quan; Jiao, Chang-geng; Yang, Su-min; Xu, Hai-bin; Duan, Yong-zhuang

2009-07-01

To study the role of PCR technique in detection of mycobacterium tuberculosis in the samples from joint tuberculosis, and to evaluate the clinical value of PCR in diagnosis of joint tuberculosis. From June 1993 to August 2001, PCR was used to detect DNA of mycobacterium tuberculosis, and the standard culture was applied to detect mycobacterium tuberculosis. Mycobacterium tuberculosis were respectively blindly by the two techniques in the samples obtained from 95 patients with joint tuberculosis (55 males and 40 females, the age ranging from 2 to 75 years, with an average of 34 years). The positive rate of mycobacterium tuberculosis detection was calculated. In the detection of mycobacterium tuberculosis, positive rate was 82% (78/95) in PCR technique, and 16% (15/95) in standard culture technique. There were statistical differences between the two groups (chi2=67, Ptechnique is a rapid, simple, sensitive and specific method for detection of mycobacterium tuberculosis in the samples of joint tuberculosis, showing more marked advantages than the standard culture technique. It is valuable in the early rapid diagnosis and differential diagnosis of joint tuberculosis.

6. Tetanus toxoid purification: chromatographic procedures as an alternative to ammonium-sulphate precipitation.

Science.gov (United States)

Stojićević, Ivana; Dimitrijević, Ljiljana; Dovezenski, Nebojša; Živković, Irena; Petrušić, Vladimir; Marinković, Emilija; Inić-Kanada, Aleksandra; Stojanović, Marijana

2011-08-01

Given an existing demand to establish a process of tetanus vaccine production in a way that allows its complete validation and standardization, this paper focuses on tetanus toxoid purification step. More precisely, we were looking at a possibility to replace the widely used ammonium-sulphate precipitation by a chromatographic method. Based on the tetanus toxin's biochemical characteristics, we have decided to examine the possibility of tetanus toxoid purification by hydrophobic chromatography, and by chromatographic techniques based on interaction with immobilized metal ions, i.e. chelating chromatography and immobilized metal affinity chromatography. We used samples obtained from differently fragmented crude tetanus toxins by formaldehyde treatment (assigned as TTd-A and TTd-B) as starting material for tetanus toxoid purification. Obtained results imply that purification of tetanus toxoid by hydrophobic chromatography represents a good alternative to ammonium-sulphate precipitation. Tetanus toxoid preparations obtained by hydrophobic chromatography were similar to those obtained by ammonium-sulphate precipitation in respect to yield, purity and immunogenicity. In addition, their immunogenicity was similar to standard tetanus toxoid preparation (NIBSC, Potters Bar, UK). Furthermore, the characteristics of crude tetanus toxin preparations had the lowest impact on the final purification product when hydrophobic chromatography was the applied method of tetanus toxoid purification. On the other hand, purifications of tetanus toxoid by chelating chromatography or immobilized metal affinity chromatography generally resulted in a very low yield due to not satisfactory tetanus toxoid binding to the column, and immunogenicity of the obtained tetanus toxoid-containing preparations was poor. Copyright © 2011 Elsevier B.V. All rights reserved.

7. Model Standards and Techniques for Control of Radon in New Residential Buildings

Science.gov (United States)

This document is intended to serve as a model for use to develop and adopt building codes, appendices to codes, or standards specifically applicable to unique local or regional radon control requirements.

8. Evaluation of the overlapping of posterior teeth in two techniques of improved interproximal panoramic program and standard panoramic

Directory of Open Access Journals (Sweden)

Goodarzi pour D

2010-06-01

Full Text Available "nBackground and Aims: Overlapping of the proximal surfaces of posterior teeth in the panoramic radiography is a major concern. Therefore, an option has been developed in the panoramic unit of Planmeca Promax, namely improved interproximal mode. This mode causes lower horizental angle with the teeth contact region during the unit rotation decreasing overlapping of the panoramic images of the posterior teeth especially premolar teeth. The present study was done to compare the overlapping of posterior teeth using two techniques of improved interproximal panoramic program and standard panoramic. "nMaterials and Methods: In this diagnostic study, 32 patients requiring panoramic radiographies at their posterior teeth during their routine diagnosis and treatment process with the mean age of 27.3 years were participated. No patients showed crowding of posterior teeth or missed and restored posterior teeth. The participants' panoramic radiographies were randomly taken by two techniques of improved interproximal panoramic and standard panoramic using Planmeca Promax device. The overlapping of the panoramic images was blindly assessed by an oral radiologist. The overlapping in both techniques was reported by frequency and percentage. The comparisons were done by Chi-square test between two techniques and the odds ratio of overlapping was estimated using regression analysis. "nResults: In standard panoramic techniques, 38.5% (148 contacts of 384 contacts of the proximal surfaces overlapped while the overlapping of the proximal surfaces was observed in 18.8% (72 contacts of 384 overall contacts in improved interproximal technique. Significant differences were noted between two techniques regarding overlapping (P<0.001. Also 66.4% and 39.1% of 4-5 teeth contacts overlapped in standard and improved techniques. The values were reported to be 39.1% and 12.5% in contacts of 5-6 teeth and 10.2% and 4.7% in the contacts of 6-7 teeth in both techniques

9. Development, modelling, optimisation and scale-up of chromatographic purification of a therapeutic protein

DEFF Research Database (Denmark)

Mollerup, Jørgen; Hansen, Thomas Budde; Kidal, Steffen

2007-01-01

optimisation of a purification step necessitate simulations and thus models of the adsorption isotherm. A model for ion-exchange is reviewed and the strategy for estimation of model parameters is reported. Examples are shown where computer simulations are used for development and optimisation......Development of a chromatographic purification step proceeds through a number of stages. High-throughput screening techniques are used to identify suitable resins. This technique is also suitable for the design of a capture step and some intermediate chromatographic steps, but development and true...

10. Large scale chromatographic separations using continuous displacement chromatography (CDC)

International Nuclear Information System (INIS)

Taniguchi, V.T.; Doty, A.W.; Byers, C.H.

1988-01-01

A process for large scale chromatographic separations using a continuous chromatography technique is described. The process combines the advantages of large scale batch fixed column displacement chromatography with conventional analytical or elution continuous annular chromatography (CAC) to enable large scale displacement chromatography to be performed on a continuous basis (CDC). Such large scale, continuous displacement chromatography separations have not been reported in the literature. The process is demonstrated with the ion exchange separation of a binary lanthanide (Nd/Pr) mixture. The process is, however, applicable to any displacement chromatography separation that can be performed using conventional batch, fixed column chromatography

11. Remnant preservation in anterior cruciate ligament reconstruction versus standard techniques: a meta-analysis of randomized controlled trials.

Science.gov (United States)

Ma, Tianjun; Zeng, Chun; Pan, Jianying; Zhao, Chang; Fang, Hang; Cai, Daozhang

2017-01-01

Preserving the remnant during anterior cruciate ligament (ACL) reconstruction is considered beneficial for graft healing, but it might increase the technical difficulties and complications. This study was to compare outcomes of using the technique of remnant preservation during the ACL reconstruction versus the standard procedure with the debridement of remnant. We searched PubMed and EMBASE and the Cochrane Library for randomized controlled trials comparing the outcomes of ACL reconstruction both with and without remnant preservation. The risk of bias was assessed in accordance with the Cochrane Collaboration's risk of bias tool. Meta-analysis was performed to compare results. Six randomized controlled trials with 346 patients were included. Statistically signiﬁcant differences in favor of using technique of remnant preservation were observed for Lysholm Score, arthrometer measurements, and tibial tunnel enlargement. There was no signiﬁcant difference between remnant technique of preservation and the standard procedure with respect to the IKDC (International Knee Documentation Committee) grade, IKDC score, Lachman Test, Pivot-shift Test, range of motion (ROM), and the incidence of the cyclops lesion. This meta-analysis of randomized controlled trials showed that ACL reconstruction with technique of remnant preservation cannot provide superior clinical outcomes compared with the standard procedure.

12. Development of sulfide calibration standards for the laser ablation inductively-coupled plasma mass spectrometry technique

Science.gov (United States)

Wilson, S.A.; Ridley, W.I.; Koenig, A.E.

2002-01-01

The requirements of standard materials for LA-ICP-MS analysis have been difficult to meet for the determination of trace elements in sulfides. We describe a method for the production of synthetic sulfides by precipitation from solution. The method is detailed by the production of approximately 200 g of a material, PS-1, with a suite of chalcophilic trace elements in an Fe-Zn-Cu-S matrix. Preliminary composition data, together with an evaluation of the homogeneity for individual elements, suggests that this type of material meets the requirements for a sulfide calibration standard that allows for quantitative analysis. Contamination of the standard with Na suggests that H2S gas may prove a better sulfur source for future experiments. We recommend that calibration data be collected in whatever mode is closest to that employed for the analysis of the unknown material, because of variable fractionation effects as a function of analytical mode. For instance, if individual spot analyses are attempted on unknown sample, then a raster of several individual spot analyses, not a continuous scan, should be collected and averaged for the standard. Hg and Au are exceptions to the above and calibration data should always be collected in a scanning mode. Au is more heterogeneously distributed than other trace metals and large-area scans are required to provide an average value for calibration purposes. We emphasize that the values given in Table 1 are preliminary values. Further chemical characterization of this standard, through a round-robin analysis program, will allow the USGS to provide both certified and recommended values for individual elements. The USGS has developed PS-1 as a potential new LA-ICP-MS standard for use by the analytical community, and requests for this material should be addressed to S. Wilson. However, it is stressed that an important aspect of the method described here is the flexibility for individual investigators to produce sulfides with a wide range

13. Standard practice for examination of welds using the alternating current field measurement technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 This practice describes procedures to be followed during alternating current field measurement examination of welds for baseline and service-induced surface breaking discontinuities. 1.2 This practice is intended for use on welds in any metallic material. 1.3 This practice does not establish weld acceptance criteria. 1.4 The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system might not be exact equivalents; therefore, each system shall be used independently of the other. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

14. Relationship between alveolar bone measured by 125I absorptiometry with analysis of standardized radiographs: 2. Bjorn technique

International Nuclear Information System (INIS)

Ortman, L.F.; McHenry, K.; Hausmann, E.

1982-01-01

The Bjorn technique is widely used in periodontal studies as a standardized measure of alveolar bone. Recent studies have demonstrated the feasibility of using 125 I absorptiometry to measure bone mass. The purpose of this study was to compare 125 I absorptiometry with the Bjorn technique in detecting small sequential losses of alveolary bone. Four periodontal-like defects of incrementally increasing size were produced in alveolar bone in the posterior segment of the maxilla of a human skull. An attempt was made to sequentially reduce the amount of bone in 10% increments until no bone remained, a through and through defect. The bone remaining at each step was measured using 125 I absorptiometry. At each site the 125 I absorptiometry measurements were made at the same location by fixing the photon source to a prefabricated precision-made occlusal splint. This site was just beneath the crest and midway between the borders of two adjacent teeth. Bone loss was also determined by the Bjorn technique. Standardized intraoral films were taken using a custom-fitted acrylic clutch, and bone measurements were made from the root apex to coronal height of the lamina dura. A comparison of the data indicates that: (1) in early bone loss, less than 30%, the Bjorn technique underestimates the amount of loss, and (2) in advanced bone loss, more than 60% the Bjorn technique overestimates it

15. Applying Standard Independent Verification and Validation (IVV) Techniques Within an Agile Framework: Is There a Compatibility Issue?

Science.gov (United States)

Dabney, James B.; Arthur, James Douglas

2017-01-01

Agile methods have gained wide acceptance over the past several years, to the point that they are now a standard management and execution approach for small-scale software development projects. While conventional Agile methods are not generally applicable to large multi-year and mission-critical systems, Agile hybrids are now being developed (such as SAFe) to exploit the productivity improvements of Agile while retaining the necessary process rigor and coordination needs of these projects. From the perspective of Independent Verification and Validation (IVV), however, the adoption of these hybrid Agile frameworks is becoming somewhat problematic. Hence, we find it prudent to question the compatibility of conventional IVV techniques with (hybrid) Agile practices.This paper documents our investigation of (a) relevant literature, (b) the modification and adoption of Agile frameworks to accommodate the development of large scale, mission critical systems, and (c) the compatibility of standard IVV techniques within hybrid Agile development frameworks. Specific to the latter, we found that the IVV methods employed within a hybrid Agile process can be divided into three groups: (1) early lifecycle IVV techniques that are fully compatible with the hybrid lifecycles, (2) IVV techniques that focus on tracing requirements, test objectives, etc. are somewhat incompatible, but can be tailored with a modest effort, and (3) IVV techniques involving an assessment requiring artifact completeness that are simply not compatible with hybrid Agile processes, e.g., those that assume complete requirement specification early in the development lifecycle.

16. MIMO wireless networks channels, techniques and standards for multi-antenna, multi-user and multi-cell systems

CERN Document Server

Clerckx, Bruno

2013-01-01

This book is unique in presenting channels, techniques and standards for the next generation of MIMO wireless networks. Through a unified framework, it emphasizes how propagation mechanisms impact the system performance under realistic power constraints. Combining a solid mathematical analysis with a physical and intuitive approach to space-time signal processing, the book progressively derives innovative designs for space-time coding and precoding as well as multi-user and multi-cell techniques, taking into consideration that MIMO channels are often far from ideal. Reflecting developments

17. Free-field reciprocity calibration of laboratory standard (LS) microphones using a time selective technique

DEFF Research Database (Denmark)

2006-01-01

Although the basic principle of reciprocity calibration of microphones in a free field is simple, the practical problems are complicated due to the low signal-to-noise ratio and the influence of cross talk and reflections from the surroundings. The influence of uncorrelated noise can be reduced...... by conventional narrow-band filtering and time averaging, while correlated signals like cross talk and reflections can be eliminated by using time-selective postprocessing techniques. The technique used at DPLA overcomes both these problems using a B&K Pulse analyzer in the SSR mode (steady state response......) and an FFT-based time-selective technique. The complex electrical transfer impedance is measured in linear frequency steps from a few kHz to about three times the resonance frequency of the microphones. The missing values at low frequencies are estimated from a detailed knowledge of the pressure...

18. The Effect of Long-Term Therapeutics, Prophylaxis and Screening Techniques on Aircrew Medical Standards.

Science.gov (United States)

1981-03-01

350. voel RA, Kirch DC, LeFree MT, Rainwater JO, Jensen DP, Steele PP. Thallium-201 myocardial perfusion scintiaraphy: results of standard aad multi...Reference 3. Further Reference 4.Security Clasification of Document A;ARD4"P-3 10 ISBN 92-835-0288-4 UNCLASSIFIE) 5 Originator Advi,,ory Group for

19. Admissions Standards and the Use of Key Marketing Techniques by United States' Colleges and Universities.

Science.gov (United States)

Goldgehn, Leslie A.

1989-01-01

A survey of admissions deans and directors investigated the use and perceived effectiveness of 15 well-known marketing techniques: advertising, advertising research, a marketing plan, market positioning, market segmentation, marketing audit, marketing research, pricing, program and service accessibility, program development, publicity, target…

20. International intercomparison of standards for low collision kerma rates in air by means of low dose TLD techniques

International Nuclear Information System (INIS)

Spanne, P.; Carlsson, C.A.; Carlsson, G.A.

1984-01-01

An international intercomparison of standards for calibration of radiation protection instruments is described. The intercomparison involved collision kerma rates in air in the range 5.7 to 7.400 μGy.h -1 and was performed using low dose TLD techniques with TL-LiF dosemeters. The dosemeters were specifically tested with regard to their dose rate dependence, but none was found. (author)

1. Assessing the service quality of Iran military hospitals: Joint Commission International standards and Analytic Hierarchy Process (AHP) technique.

Science.gov (United States)

2014-01-01

Military hospitals are responsible for preserving, restoring and improving the health of not only armed forces, but also other people. According to the military organizations strategy, which is being a leader and pioneer in all areas, providing quality health services is one of the main goals of the military health care organizations. This study was aimed to evaluate the service quality of selected military hospitals in Iran based on the Joint Commission International (JCI) standards and comparing these hospitals with each other and ranking them using the analytic hierarchy process (AHP) technique in 2013. This was a cross-sectional and descriptive study conducted on five military hospitals, selected using the purposive sampling method, in 2013. Required data collected using checklists of accreditation standards and nominal group technique. AHP technique was used for prioritizing. Furthermore, Expert Choice 11.0 was used to analyze the collected data. Among JCI standards, the standards of access to care and continuity of care (weight = 0.122), quality improvement and patient safety (weight = 0.121) and leadership and management (weight = 0.117) had the greatest importance, respectively. Furthermore, in the overall ranking, BGT (weight = 0.369), IHM (0.238), SAU (0.202), IHK (weight = 0.125) and SAB (weight = 0.066) ranked first to fifth, respectively. AHP is an appropriate technique for measuring the overall performance of hospitals and their quality of services. It is a holistic approach that takes all hospital processes into consideration. The results of the present study can be used to improve hospitals performance through identifying areas, which are in need of focus for quality improvement and selecting strategies to improve service quality.

2. Evaluation of a standard breast tangent technique: a dose-volume analysis of tangential irradiation using three-dimensional tools

International Nuclear Information System (INIS)

Krasin, Matthew; McCall, Anne; King, Stephanie; Olson, Mary; Emami, Bahman

2000-01-01

3. Phytochemical analysis and standardization of Strychnos nux-vomica extract through HPTLC techniques

Directory of Open Access Journals (Sweden)

Dinesh Kumar Patel

2012-05-01

Full Text Available Objective: The objective is to develop a noval qualitative and quantitative method by which we can determine different phytoconstituents of Strychnos nux-vomica L. Methods: To profile the phyconstituents of Strychnos nux-vomica, in the present study hydroalcoholic extract of Strychnos nux-vomica was subjected to preliminary phytochemical analysis, antimicrobial activities against certain pathogenic microorganisms, solubility test, loss on drying and pH value. Extract was also subjected to the quantitative analysis including total phenol, flavonoid and heavy metal analysis. Quantitative analysis was performed through HPTLC methods using strychnine and brucine as a standard marker. Results: Phytochemical analysis revealed the presence of alkaloid, carbohydrate, tannin, steroid, triterpenoid and glycoside in the extract. Total flavonoid and phenol content of Strychnos nux-vomica L extract was found to be 0.40 % and 0.43%. Result showed that the level of heavy metal (lead, arsenic, mercury and cadmium complie the standard level. Total bacterial count, yeast and moulds contents were found to be under the limit whereas E. coli and salmonella was found to be absent in the extract. Content of strychnine and brucine were found to be 4.75% and 3.91%. Conclusions: These studies provide valluable information for correct identification and selection of the drug from various adulterations. In future this study will be helpful for the quantitative analysis as well as standardization of the Strychnos nux-vomica L.

4. A Simple low-cost device enables four epi-illumination techniques on standard light microscopes.

Science.gov (United States)

Ishmukhametov, Robert R; Russell, Aidan N; Wheeler, Richard J; Nord, Ashley L; Berry, Richard M

2016-02-08

Back-scattering darkfield (BSDF), epi-fluorescence (EF), interference reflection contrast (IRC), and darkfield surface reflection (DFSR) are advanced but expensive light microscopy techniques with limited availability. Here we show a simple optical design that combines these four techniques in a simple low-cost miniature epi-illuminator, which inserts into the differential interference-contrast (DIC) slider bay of a commercial microscope, without further additions required. We demonstrate with this device: 1) BSDF-based detection of Malarial parasites inside unstained human erythrocytes; 2) EF imaging with and without dichroic components, including detection of DAPI-stained Leishmania parasite without using excitation or emission filters; 3) RIC of black lipid membranes and other thin films, and 4) DFSR of patterned opaque and transparent surfaces. We believe that our design can expand the functionality of commercial bright field microscopes, provide easy field detection of parasites and be of interest to many users of light microscopy.

5. Standardization of the radioimmunoassay technique for the determination of human gastrin and its clinical application

International Nuclear Information System (INIS)

Peig Ginabredra, M.G.

1989-01-01

It was developed and standardized a system of radioimmunoassay for the determination of gastrin, employing synthetic human gastrin for radioiodination and preparation of standard as well as specific antibody raised rabbits. The hormone was labeled with 125 I by the Cloramine T techique and purified by anion exchange chromatography in QAE-Sephadex A-25, being determined its specific activity. The tracer thus obtained was submitted to analysis of purity by poliacrilamide gel eletrophoresis and precipitation of proteins by trichloroacetic acid. Its stability evaluated according to the time of storage, being its purity and adequation for the use in radioimmunoassay also compared to a tracer obtained from a commercial diagnosis kit. The assays were performed by incubation of radioiodinated gastrin, standard gastrin prepared in plasma free from this hormone (from zero to 500 pmol/l) or samples to be assayed with the antiserum for 4 days at 4 0 C. The separation between the free gastrin and the gastrin bound to the antibody was carried out by adsorption of the free hormone to the charcoal, whose ideal concentration was previously determined. Plasma free from gastrin was obtained from time-expired blood bank plasma submitted to extraction with charcoal. When performed the quality control, this radioimmunoassay was shown specific, accurate, precise and sensitive, allowing the performance of valid assays. Its validation was even confirmed by clear discrimination not only of the gastrin concentration in subjects with very low levels (gastrectomized) and extremely high levels (Zollinger-Ellison syndrome) as well as gastrin concentrations in subjects with other diseases, such as Chagas disease, pernicious anemia and chronic renal failure. (author) [pt

6. Antidiarrhoeal Activity of Chromatographic Fractions of ...

African Journals Online (AJOL)

Erah

Purpose: The present study was undertaken in order to evaluate the antidiarrhoeal activity of three chromatographic fractions (L, S and Y) of Stereospermum kunthianum stem bark in mice. Methods: Vacuum liquid/column chromatography (VLC/ CC) were used to obtain three fractions (L,S and Y) of Stereospermum ...

7. Liquid chromatographic determination of pyrethroid insecticide ...

African Journals Online (AJOL)

A new high performance liquid chromatography (HPLC) method for the quantitative analysis of cypermethrin in vegetable samples has been described. The determination of cypermethrin was carried out on Kromosil C18 analytical column (250 mm × 4.6 mm I.D., 5 μm particle size), under reversed phase chromatographic ...

8. Liquid chromatographic analysis of phenobarbitone, ethosuximide ...

African Journals Online (AJOL)

A liquid chromatographic method for the simultaneous assay of four anticonvulsant drugs, phenobarbitone, ethosuximide, phenytoin and carbamazepine on a polystyrene-divinyl benzene column is described. The method was developed by the systematic study of different types of co-polymer materials, type and ...

9. Rapid validated liquid chromatographic method coupled with ...

African Journals Online (AJOL)

Abstract. Purpose: To develop and validate a fast, sensitive, and simple liquid chromatographic method coupled with tandem mass spectrometry for the ... European Medicines Agency (EMA) guidelines. Results: The proposed method ... that few articles were published for NTB quantification in rat biological fluids and tissues.

10. High performance liquid chromatographic determination of ...

African Journals Online (AJOL)

STORAGESEVER

2010-02-08

Feb 8, 2010 ... liquid chromatographic with UV/Fluorescence detection is described. Proguanil was derivatised to its corresponding ... proguanil in combination with other antimalarial drugs has also been reported to posses synergic toxicity ..... Chlorophenyl Biguanide in Biological Fluids. Afr. J. Biotechnol. 4(8):. 856-861.

11. Chromatographic characterisation, in vitro antioxidant and free ...

African Journals Online (AJOL)

Chromatographic fractionation and spectroscopic analysis of the ME4 fraction revealed the presence of four compounds namely garcinia biflavonoids GB1 and GB2, garcinal and garcinoic acid. These findings show that these four compounds are partly responsible for the great antioxidant potential of G. kola seeds.

12. Characterization of the neutron sources storage pool of the Neutron Standards Laboratory, using Montecarlo Techniques

International Nuclear Information System (INIS)

Campo Blanco, X.

2015-01-01

The development of irradiation damage resistant materials is one of the most important open fields in the design of experimental facilities and conceptual nucleoelectric fusion plants. The Neutron Standards Laboratory aims to contribute to this development by allowing the neutron irradiation of materials in its calibration neutron sources storage pool. For this purposes, it is essential to characterize the pool itself in terms of neutron fluence and spectra due to the calibration neutron sources. In this work, the main features of this facility are presented and the characterization of the storage pool is carried out. Finally, an application is shown of the obtained results to the neutron irradiation of material.

13. A Small-Scale Low-Cost Gas Chromatograph

Science.gov (United States)

Gros, Natasa; Vrtacnik, Margareta

2005-01-01

The design and application of a small-scale portable gas chromatograph for learning of the basic concepts of chromatography is described. The apparatus consists of two basic separable units, which includes a chromatographic unit and an electronic unit.

14. Chromatographic Methods for the Analysis of Polyphenols in Wines

Directory of Open Access Journals (Sweden)

Medić-Šarić, M.

2009-03-01

Full Text Available Wine is an excellent source of various classes of polyphenols, including phenolic acids, flavonoids, and trihydroxystilbene resveratrol (Fig.1. Polyphenols play a major role in wine quality since they contribute to the sensory characteristics of wine, particularly color and astringency. A recent interest in these substances has been stimulated by abundant evidence of their beneficial effects on human health, such as anticarcinogenic, antiinflamatory and antimicrobial activities. Therefore, numerous studies have been performed in the attempt to analyze polyphenols in wine. This paper reviews the current advances in the determination of polyphenols in wine by the major chromatographic techniques such as thin-layer chromatography (TLC and high-performance liquid chromatography (HPLC.The great complexity of the polyphenolic content of wine and the difficulty in obtaining some of the standards usually require sample preparation before analysis. Two methods for sample preparation, liquid-liquid extraction and solid-phase extraction, are most commonly applied. Hydrolysis is applied frequently, but not exclusively, to remove the sugar moieties from glycosides.TLC on silica gel plates is useful for the rapid and low-cost separation and identification of the polyphenols present in wine (Fig. 2. Densitometric quantitative analysis of polyphenols in wine extracts is usually performed by scanning the TLC plates with UV light at wavelengths of 350–365 nm or 250–260 nm (Fig. 3. For the evaluation of the most efficient mobile phase and an optimal choice of the combination of two or more mobile phases, two methods may be applied: information theory and numerical taxonomy. HPLC currently represents the most popular technique for the analysis of polyphenols in wine. For this purpose, a reversed-phase HPLC method that uses gradient elution with binary elution system is usually employed. Routine detection is based on measurement of UV-Vis absorption with a diode

15. High Performance Liquid Chromatographic Method for Determination of Dipyridamole in Human Plasma

Directory of Open Access Journals (Sweden)

1999-08-01

Full Text Available A simple, rapid and specific high-performance liquid chromatographic procedure is reported for"nquantitative determination of dipyridamole in human -plasma. The assay uses a reversed-phase"nhigh-performance liquid chromatographic (HPLC and UV detection at 280nm and has a limit"nof detection of approximately 5ng/mL. The mobile phase consists of MeOH-H20 (60:40"nadjusted to pH 3.3. Dipyridamole was extracted from plasma by back-extraction procedure, with"npropranolol as the internal standard. The reproducibility of the method is satisfactory

16. The combination of the liquid chromatograph with the nuclear magnetic resonance spectrometer

International Nuclear Information System (INIS)

Scott, R.P.W.

1986-01-01

The association of the liquid chromatograph with the NMR spectrometer would be a very powerful analytical system for the separation and identification of unknown mixtures. There are, however, some serious difficulties involved with the association of these two techniques. The historical development of NMR chromatography is outlined and some problems are discussed. (Auth.)

17. Evaluation of Visualization Using a 50/50 (Contrast Media/Glucose 5% Solution) Technique for Radioembolization as an Alternative to a Standard Sandwich Technique.

Science.gov (United States)

Paprottka, Karolin J; Todica, Andrei; Ilhan, Harun; Rübenthaler, Johannes; Schoeppe, Franziska; Michl, Marlies; Heinemann, Volker; Bartenstein, Peter; Reiser, Maximilian F; Paprottka, Philipp M

2017-11-01

Radioembolization (RE) with 90 yttrium ( 90 Y) resin microspheres generally employs a sandwich technique with separate sequential administration of contrast medium (CM), followed by vehicle (e.g., glucose 5% [G5] solution), then 90 Y resin microspheres (in G5), then G5, and then CM again to avoid contact of CM and microspheres under fluoroscopic guidance. This study evaluates the visualization quality and safety of a modified sandwich technique with a 50/50-mixture of CM (Imeron 300) and G5 for administration of 90 Y resin microspheres. A retrospective analysis of 81 RE procedures in patients with primary or secondary liver tumors was performed. The quality of angiographic visualization of the hepatic vessels was assessed before the first injection and immediately before the whole dose has been injected. Visualization and flow rate were graded on a 5-point scale: 1 = very good to 5 = not visible/no antegrade flow. Univariate logistic regression models and multiple linear regression models were used to evaluate the prognostic variables associated with visualization and flow scores. Visualization quality was inversely related to flow rate, the lower the flow rate the better the grade of the visualization. Visualization quality was also inversely related to body-mass-index (BMI). Performing RE with the 50/50-CM/G5 mixture resulted in a mean injection time for 1 GBq of 15 min. No clinically significant adverse events, including radiation-induced liver disease were reported. RE with a 50/50-mixture of CM and G5 for administration of 90 Y resin microspheres in a modified sandwich technique is a safe administration alternative and provides good visualization of hepatic vessels, which is inversely dependent on flow rate and BMI. Injection time was reduced compared with our experience with the standard sandwich technique.

18. Robot-assisted repair of tricuspid leaflet prolapse using standard valvuloplasty techniques.

Science.gov (United States)

Seder, Christopher W; Suri, Rakesh M; Rehfeldt, Kent; Pislaru, Sorin; Burkhart, Harold M

2012-11-01

While minimally invasive approaches are used routinely to correct severe mitral regurgitation due to leaflet prolapse, isolated tricuspid valve prolapse is less frequent and usually addressed via sternotomy. A 34-year-old female presented with exertional dyspnea and severe tricuspid regurgitation due to an unsupported anterior leaflet causing prolapse, a tethered septal leaflet, and dilated annulus. Herein, the technique is described of a robot-assisted tricuspid valve repair using established open valvuloplasty principles. The robotic repair was performed by the placement of Gore-Tex neochordae from the anterior papillary muscle to the anterior tricuspid leaflet, plication of the anteroseptal and anteroposterior commissures, closure of an anterior leaflet cleft, and the insertion of an annuloplasty band. The patient had an uncomplicated hospital course and was dismissed home on the third postoperative day.

19. Model-Based Data Integration and Process Standardization Techniques for Fault Management: A Feasibility Study

Science.gov (United States)

Haste, Deepak; Ghoshal, Sudipto; Johnson, Stephen B.; Moore, Craig

2018-01-01

This paper describes the theory and considerations in the application of model-based techniques to assimilate information from disjoint knowledge sources for performing NASA's Fault Management (FM)-related activities using the TEAMS® toolset. FM consists of the operational mitigation of existing and impending spacecraft failures. NASA's FM directives have both design-phase and operational-phase goals. This paper highlights recent studies by QSI and DST of the capabilities required in the TEAMS® toolset for conducting FM activities with the aim of reducing operating costs, increasing autonomy, and conforming to time schedules. These studies use and extend the analytic capabilities of QSI's TEAMS® toolset to conduct a range of FM activities within a centralized platform.

20. Standard practice for evaluation of hydrogen uptake, permeation, and transport in metals by an electrochemical technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

1997-01-01

1.1 This practice gives a procedure for the evaluation of hydrogen uptake, permeation, and transport in metals using an electrochemical technique which was developed by Devanathan and Stachurski. While this practice is primarily intended for laboratory use, such measurements have been conducted in field or plant applications. Therefore, with proper adaptations, this practice can also be applied to such situations. 1.2 This practice describes calculation of an effective diffusivity of hydrogen atoms in a metal and for distinguishing reversible and irreversible trapping. 1.3 This practice specifies the method for evaluating hydrogen uptake in metals based on the steady-state hydrogen flux. 1.4 This practice gives guidance on preparation of specimens, control and monitoring of the environmental variables, test procedures, and possible analyses of results. 1.5 This practice can be applied in principle to all metals and alloys which have a high solubility for hydrogen, and for which the hydrogen permeation is ...

1. Pyrite: A blender plugin for visualizing molecular dynamics simulations using industry-standard rendering techniques.

Science.gov (United States)

Rajendiran, Nivedita; Durrant, Jacob D

2018-05-05

Molecular dynamics (MD) simulations provide critical insights into many biological mechanisms. Programs such as VMD, Chimera, and PyMOL can produce impressive simulation visualizations, but they lack many advanced rendering algorithms common in the film and video-game industries. In contrast, the modeling program Blender includes such algorithms but cannot import MD-simulation data. MD trajectories often require many gigabytes of memory/disk space, complicating Blender import. We present Pyrite, a Blender plugin that overcomes these limitations. Pyrite allows researchers to visualize MD simulations within Blender, with full access to Blender's cutting-edge rendering techniques. We expect Pyrite-generated images to appeal to students and non-specialists alike. A copy of the plugin is available at http://durrantlab.com/pyrite/, released under the terms of the GNU General Public License Version 3. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

2. Psychovisual masks and intelligent streaming RTP techniques for the MPEG-4 standard

Science.gov (United States)

Mecocci, Alessandro; Falconi, Francesco

2003-06-01

In today multimedia audio-video communication systems, data compression plays a fundamental role by reducing the bandwidth waste and the costs of the infrastructures and equipments. Among the different compression standards, the MPEG-4 is becoming more and more accepted and widespread. Even if one of the fundamental aspects of this standard is the possibility of separately coding video objects (i.e. to separate moving objects from the background and adapt the coding strategy to the video content), currently implemented codecs work only at the full-frame level. In this way, many advantages of the flexible MPEG-4 syntax are missed. This lack is due both to the difficulties in properly segmenting moving objects in real scenes (featuring an arbitrary motion of the objects and of the acquisition sensor), and to the current use of these codecs, that are mainly oriented towards the market of DVD backups (a full-frame approach is enough for these applications). In this paper we propose a codec for MPEG-4 real-time object streaming, that codes separately the moving objects and the scene background. The proposed codec is capable of adapting its strategy during the transmission, by analysing the video currently transmitted and setting the coder parameters and modalities accordingly. For example, the background can be transmitted as a whole or by dividing it into "slightly-detailed" and "highly detailed" zones that are coded in different ways to reduce the bit-rate while preserving the perceived quality. The coder can automatically switch in real-time, from one modality to the other during the transmission, depending on the current video content. Psychovisual masks and other video-content based measurements have been used as inputs for a Self Learning Intelligent Controller (SLIC) that changes the parameters and the transmission modalities. The current implementation is based on the ISO 14496 standard code that allows Video Objects (VO) transmission (other Open Source Codes

3. Two-loop renormalization in the standard model, part II. Renormalization procedures and computational techniques

Energy Technology Data Exchange (ETDEWEB)

Actis, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Passarino, G. [Torino Univ. (Italy). Dipt. di Fisica Teorica; INFN, Sezione di Torino (Italy)

2006-12-15

In part I general aspects of the renormalization of a spontaneously broken gauge theory have been introduced. Here, in part II, two-loop renormalization is introduced and discussed within the context of the minimal Standard Model. Therefore, this paper deals with the transition between bare parameters and fields to renormalized ones. The full list of one- and two-loop counterterms is shown and it is proven that, by a suitable extension of the formalism already introduced at the one-loop level, two-point functions suffice in renormalizing the model. The problem of overlapping ultraviolet divergencies is analyzed and it is shown that all counterterms are local and of polynomial nature. The original program of 't Hooft and Veltman is at work. Finite parts are written in a way that allows for a fast and reliable numerical integration with all collinear logarithms extracted analytically. Finite renormalization, the transition between renormalized parameters and physical (pseudo-)observables, are discussed in part III where numerical results, e.g. for the complex poles of the unstable gauge bosons, are shown. An attempt is made to define the running of the electromagnetic coupling constant at the two-loop level. (orig.)

4. Standard Test Methods for Total Normal Emittance of Surfaces Using Inspection-Meter Techniques

CERN Document Server

American Society for Testing and Materials. Philadelphia

1971-01-01

1.1 These test methods cover determination of the total normal emittance (Note) of surfaces by means of portable, inspection-meter instruments. Note 1—Total normal emittance (εN) is defined as the ratio of the normal radiance of a specimen to that of a blackbody radiator at the same temperature. The equation relating εN to wavelength and spectral normal emittance [εN (λ)] is where: L b(λ, T) = Planck's blackbody radiation function = c1π −1λ−5(ec2/λT − 1)−1, c1 = 3.7415 × 10−16 W·m 2, c2 = 1.4388 × 10−2 m·K, T = absolute temperature, K, λ = wavelength, m, Lb(λ, T)dλ = Δπ −1T4, and Δ = Stefan-Boltzmann constant = 5.66961 × 10 −8 W·m2·K−4 1.2 These test methods are intended for measurements on large surfaces when rapid measurements must be made and where a nondestructive test is desired. They are particularly useful for production control tests. 1.3 The values stated in SI units are to be regarded as standard. No other units of measu...

5. Optimization of the gas chromatographic separations; Optimacion de las separaciones cromatograficas en fase gaseosa

Energy Technology Data Exchange (ETDEWEB)

Gasco Sanchez, L.

1973-07-01

A review and a critical study on the optimization of the gas chromatographic separations are made. After dealing with the fundamental gas chromatographic equations, some methods of expressing column performances are discussed: performance indices, performance parameters, resolution and effective plate number per unit time. This is completed with a comparative study on performances of various types of columns. Moreover, optimization methods for operating chromatographic conditions are extensively dealt with: as resolution optimization, separation time, and normalization techniques for the time of analysis in order to achieve the maximum resolution at constant time. Finally, some others non operating parameters such as: selectivity of stationary phases, column preparation and optimization methods by means of computers are studied. (Author) 68 refs.

6. Chromatographic determination of silicon and phosphorus as molybdic heteropoly acids with preconcentration

International Nuclear Information System (INIS)

Tikhomirova, T.I.; Krokhin, O.V.; Dubovik, D.B.; Ivanov, A.V.; Shpigun, O.A.

2002-01-01

Chromatographic behaviour of silicon and phosphorus as molybdic heteropoly acids with preconcentration as ion associations of heteropoly acid with tributylammonium bromide was studied. The technique of simultaneous analysis of silicon and phosphorus was developed. During investigation into the effect of acetonitril content in the probe on the form of chromatographic peak of molybdosilicic acid the negative influence of acetonitril on the form of peak was ascertained. This effect may be eliminated by the lowering of acetonitril content up to 50 %. It was found that under these conditions the chromatographic peak practically was absent, because of the heteropoly acid of the Mo(VI) abundance transformed in the MoO 2 2+ cation form without reaction with tributylammonium cation during concentration of heteropoly acid [ru

7. Watermarking Techniques Using Least Significant Bit Algorithm for Digital Image Security Standard Solution- Based Android

Directory of Open Access Journals (Sweden)

Ari Muzakir

2017-05-01

Full Text Available Ease of deployment of digital image through the internet has positive and negative sides, especially for owners of the original digital image. The positive side of the ease of rapid deployment is the owner of that image deploys digital image files to various sites in the world address. While the downside is that if there is no copyright that serves as protector of the image it will be very easily recognized ownership by other parties. Watermarking is one solution to protect the copyright and know the results of the digital image. With Digital Image Watermarking, copyright resulting digital image will be protected through the insertion of additional information such as owner information and the authenticity of the digital image. The least significant bit (LSB is one of the algorithm is simple and easy to understand. The results of the simulations carried out using android smartphone shows that the LSB watermarking technique is not able to be seen by naked human eye, meaning there is no significant difference in the image of the original files with images that have been inserted watermarking. The resulting image has dimensions of 640x480 with a bit depth of 32 bits. In addition, to determine the function of the ability of the device (smartphone in processing the image using this application used black box testing.

8. Chromatographic study of Euphorbia cyparissias

Directory of Open Access Journals (Sweden)

Cristina, T. Romeo,

2009-12-01

Full Text Available The ectoparasitic population control is very difficult and includes numerous chemical substances and therapeutic techniques. Although efficient at first, the repeated use of acaricidal substances leads to the appearance of resistance. The more and more reduced efficacy of the therapeutic arsenal puts serious problems for the practitionersand increases the need of newer substances on the market. Besides this appears the problem of residues in eggs and meat, which is a serious impediment. Because of this the use of plant extracts is an attractive and promising research path. The investigations tied to the parasitic biocontrol have diversified with the study of the numerous control sources (fungi, plant extracts, volatile oils etc..In this context, the plant extracts can become an alternative source for the acaricidal control knowing that they constitute a rich source of efficient bioactive compounds. Unfortunately although at hand until today, not very much data is known about what determines theacaricidal activity of some plant extracts against the argaside ticks.The present work describes an in vitro CG-MS study for identification of Euphorbia cyparissias’ chemical composition.

9. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

Energy Technology Data Exchange (ETDEWEB)

Campo B, X.; Mendez V, R.; Embid S, M. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Sanz G, J., E-mail: xandra.campo@ciemat.es [Universidad Nacional de Educacion a Distancia, Escuela Tecnica Superior de Ingenieros Industriales, C. Juan del Rosal 12, 28040 Madrid (Spain)

2014-08-15

Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with {sup 241}Am-Be (185 GBq) and {sup 252}Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the {sup 252}Cf source. This source predominates and the effect of the {sup 241}Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

10. Characterization of the storage pool of the Neutron Standards Laboratory of CIEMAT, using Monte Carlo techniques

International Nuclear Information System (INIS)

Campo B, X.; Mendez V, R.; Embid S, M.; Vega C, H. R.; Sanz G, J.

2014-08-01

Neutron Standards Laboratory of CIEMAT in Spain is a brand new irradiation facility, with 241 Am-Be (185 GBq) and 252 Cf (5 GBq) calibrated neutron sources which are stored in a water pool with a concrete cover. From this storage place an automated system is able to take the selected source and place it in the irradiation position, 4 m over the ground level and in the geometrical center of the Irradiation Room with 9 m (length) x 7.5 m (width) x 8 m (height). For calibration or irradiation purposes, detectors or materials can be placed on a bench but it is possible to use the pool (1.0 m x 1.5 m and more than 1.0 m depth) for long time irradiations in thermal neutron fields. For this reason it is essential to characterize the pool itself in terms of neutron spectrum. In this document, the main features of this facility are presented and the characterization of the storage pool in terms of neutron fluence rate and neutron spectrum has been carried out using simulations with MCNPX-2.7.e code. The MCNPX-2.7.e model has been validated using experimental measurements outside the pool (Bert hold LB6411). Inside the pool, the fluence rate decreases and the spectra is thermalized with the distance to the 252 Cf source. This source predominates and the effect of the 241 Am-Be source in these magnitudes is not shown until positions closer than 20 cm from it. (author)

11. Comparison of four different techniques to evaluate the elastic properties of phantom in elastography: is there a gold standard?

Science.gov (United States)

Oudry, Jennifer; Lynch, Ted; Vappou, Jonathan; Sandrin, Laurent; Miette, Véronique

2014-10-07

Elastographic techniques used in addition to imaging techniques (ultrasound, resonance magnetic or optical) provide new clinical information on the pathological state of soft tissues. However, system-dependent variation in elastographic measurements may limit the clinical utility of these measurements by introducing uncertainty into the measurement. This work is aimed at showing differences in the evaluation of the elastic properties of phantoms performed by four different techniques: quasi-static compression, dynamic mechanical analysis, vibration-controlled transient elastography and hyper-frequency viscoelastic spectroscopy. Four Zerdine® gel materials were tested and formulated to yield a Young's modulus over the range of normal and cirrhotic liver stiffnesses. The Young's modulus and the shear wave speed obtained with each technique were compared. Results suggest a bias in elastic property measurement which varies with systems and highlight the difficulty in finding a reference method to determine and assess the elastic properties of tissue-mimicking materials. Additional studies are needed to determine the source of this variation, and control for them so that accurate, reproducible reference standards can be made for the absolute measurement of soft tissue elasticity.

12. Standardization of the Fricke gel dosimetry method and tridimensional dose evaluation using the magnetic resonance imaging technique

International Nuclear Information System (INIS)

Cavinato, Christianne Cobello

2009-01-01

This study standardized the method for obtaining the Fricke gel solution developed at IPEN. The results for different gel qualities used in the preparation of solutions and the influence of the gelatin concentration in the response of dosimetric solutions were compared. Type tests such as: dose response dependence, minimum and maximum detection limits, response reproducibility, among others, were carried out using different radiation types and the Optical Absorption (OA) spectrophotometry and Magnetic Resonance (MR) techniques. The useful dose ranges for Co 60 gamma radiation and 6 MeV photons are 0,4 to 30,0 Gy and 0,5 to 100,0 Gy , using OA and MR techniques, respectively. A study of ferric ions diffusion in solution was performed to determine the optimum time interval between irradiation and samples evaluation; until 2,5 hours after irradiation to obtain sharp MR images. A spherical simulator consisting of Fricke gel solution prepared with 5% by weight 270 Bloom gelatine (national quality) was developed to be used to three-dimensional dose assessment using the Magnetic Resonance Imaging (MRI) technique. The Fricke gel solution prepared with 270 Bloom gelatine, that, in addition to low cost, can be easily acquired on the national market, presents satisfactory results on the ease of handling, sensitivity, response reproducibility and consistency. The results confirm their applicability in the three-dimensional dosimetry using MRI technique. (author)

13. The 'Pull' Technique for Removal of Peritoneal Dialysis Catheters: A Call for Re-Evaluation of Practice Standards.

Science.gov (United States)

Grieff, Marvin; Mamo, Elizabeth; Scroggins, Gina; Kurchin, Alexander

2017-01-01

♦ BACKGROUND: The most commonly used peritoneal dialysis (PD) catheters have silicon tubing with attached Dacron cuffs. The current standard of care for PD catheter removal is by complete surgical dissection, withdrawing both the tubing and the cuffs. The intention is to avoid infection of any residual part of the catheter. We retrospectively analyzed our results with the alternative 'pull' technique, by which the silicon tube is pulled out, leaving the Dacron cuffs within the abdominal wall. This technique never gained popularity due to concern that the retained cuffs would get infected. ♦ METHODS: We reviewed our experience from an 18-month period, between January 2014 and June 2015. There were 46 catheter removals in 40 patients. All the catheters were of the double-cuffed coiled Tenckhoff type (Covidien, Dublin, Ireland). ♦ RESULTS: Of the 46 catheter removals by the 'pull' technique, there was only 1 case of retained cuff infection. ♦ CONCLUSIONS: The 'pull' technique is a safe method for Tenckhoff catheter removal with low risk of infection. We strongly recommend it as the procedure of choice. Copyright © 2017 International Society for Peritoneal Dialysis.

14. [The standard implantation of a total hip prosthesis via two incisions (the Yale Technique)].

Science.gov (United States)

Kipping, Robert

2009-09-01

Implantation of a total hip endoprosthesis with minimal trauma to the soft tissue. The need for visual aids (e.g., navigation or X-rays) during the procedure is frequently avoided. All kinds of coxarthrosis for every age group, for every variation of bone construction, and even in obese patients. Extremely dysplastic hip joints involving the development of a secondary socket and the necessity of reconstruction of the acetabular socket (e.g., in the Harris method). Using a fixed lateral position, a small entry incision is made between the tensor fasciae latae and the sartorius muscles and the prosthesis socket is put into place. Via a second dorsal incision, after stripping the exterior rotators, the prosthesis stem and ball are implanted and the two parts of the prosthesis are attached. Full weight bearing allowed immediately. A luxation prophylaxis, in the form of a self-developed hip bodice (the so-called Yale bandage), is used until the end of the 4th postoperative week. Discharge from hospital is possible after just a few days. Upon discharge, the patient is sent to a rehabilitation facility, either as a resident or as an outpatient, for approximately 3 weeks. Return to the workplace, with only light physical activity, is possible once the wound has healed completely; this could be as soon as 14 days after the operation. Checkups are made after 4 weeks, 6 months, 1 year and then every year; these checkups include a full examination, X-rays and laboratory tests. Full exposure to sport or heavy manual labor is usually approved after the 6-month checkup. Between October 2004 and April 2006, a total of 221 patients underwent surgery using this new technique (of these 15 patients underwent two-stage bilateral hip joint replacements). Patients were followed up for a minimum of 12 months and a maximum of 30 months. The Harris Hip Score improved from an average of 45.25 preoperatively to 96.4 postoperatively.

15. Evaluation of a thin-layer chromatographic technique for ...

African Journals Online (AJOL)

Methanol extracts of both fistula and bush samples were prepared and analysed by thin-layer chromatography. Chromatoplates, when visualised under ultraviolet light, revealed a number of fluorescent compounds, some of which were common in both the fistula and bush sample extracts. By comparing the presence of ...

16. Chromatographic separation of human salivary peroxidases.

Science.gov (United States)

Mäkinen, K K; Tenovuo, J

1976-01-01

A series of rapid and simple chromatographic purification procedures for peroxidase-like enzymes occurring in the human oral cavity is presented. Samples of whole saliva, parotid saliva, gingival exudate and various bacterial preparations contain peroxidases which were purified using molecular exclusion and ion exchange chromatography, and isoelectric focusing. Salivary lactoperoxidase can be easily separated from bacterial and leucocyte peroxidase activity by the methods presented.

17. GAS CHROMATOGRAPHIC AND SPECTROSCOPIC ANALYSIS OF ...

African Journals Online (AJOL)

Peroxyformic acid prepared in-situ was employed for epoxidation of canola oil in the presence of toluene. Gas chromatographic analysis of the product revealed the following species: C16:0; C18:0; C18:1; C18:2; C18:3; monoepoxy C18:0; monoepoxy C18:1; monoepoxy C18:2; diepoxy C18:0; diepoxy C18:1 and triepoxy ...

18. Russian Language Development Assessment as a Standardized Technique for Assessing Communicative Function in Children Aged 3–9 Years

Directory of Open Access Journals (Sweden)

Prikhoda N.A.,

2016-10-01

Full Text Available The article describes the Russian Language Development Assessment, a standardized individual diagnostic tool for children aged from 3 to 9 that helps to assess the following components of a child’s communicative function: passive vocabulary, expressive vocabulary, knowledge of semantic constructs with logical, temporal and spatial relations, passive perception and active use of syntactic and morphological features of words in a sentence, active and passive phonological awareness, active and passive knowledge of syntactic structures and categories. The article provides descriptions of content and diagnostic procedures for all 7 subtests included in the assessment (Passive Vocabulary, Active Vocabulary, Linguistic Operators, Sentence structure, Word Structure, Phonology, Sentence Repetition. Basing on the data collected in the study that involved 86 first- graders of a Moscow school, the article analyzes the internal consistency and construct validity of each subtest of the technique. It concludes that the Russian Language Development Assessment technique can be of much use both in terms of diagnostic purposes and in supporting children with ASD taking into account the lack of standardized tools for language and speech development assessment in Russian and the importance of this measure in general.

19. A comparative study of standard vs. high definition colonoscopy for adenoma and hyperplastic polyp detection with optimized withdrawal technique.

Science.gov (United States)

East, J E; Stavrindis, M; Thomas-Gibson, S; Guenther, T; Tekkis, P P; Saunders, B P

2008-09-15

Colonoscopy has a known miss rate for polyps and adenomas. High definition (HD) colonoscopes may allow detection of subtle mucosal change, potentially aiding detection of adenomas and hyperplastic polyps. To compare detection rates between HD and standard definition (SD) colonoscopy. Prospective, cohort study with optimized withdrawal technique (withdrawal time >6 min, antispasmodic, position changes, re-examining flexures and folds). One hundred and thirty patients attending for routine colonoscopy were examined with either SD (n = 72) or HD (n = 58) colonoscopes. Groups were well matched. Sixty per cent of patients had at least one adenoma detected with SD vs. 71% with HD, P = 0.20, relative risk (benefit) 1.32 (95% CI 0.85-2.04). Eighty-eight adenomas (mean +/- standard deviation 1.2 +/- 1.4) were detected using SD vs. 93 (1.6 +/- 1.5) with HD, P = 0.12; however more nonflat, diminutive (9 mm) hyperplastic polyps was 7% (0.09 +/- 0.36). High definition did not lead to a significant increase in adenoma or hyperplastic polyp detection, but may help where comprehensive lesion detection is paramount. High detection rates appear possible with either SD or HD, when using an optimized withdrawal technique.

International Nuclear Information System (INIS)

Mrochek, J.E.; Shumate, S.E.; Genung, R.K.; Bahner, C.T.; Lee, N.E.; Dinsmore, S.R.

1976-01-01

The development of several new analytical techniques for use in clinical diagnosis and biomedical research is reported. These include: high-resolution liquid chromatographic systems for the early detection of pathological molecular constituents in physiologic body fluids; gradient elution chromatography for the analysis of protein-bound carbohydrates in blood serum samples, with emphasis on changes in sera from breast cancer patients; electrophoretic separation techniques coupled with staining of specific proteins in cellular isoenzymes for the monitoring of genetic mutations and abnormal molecular constituents in blood samples; and the development of a centrifugal elution chromatographic technique for the assay of specific proteins and immunoglobulins in human blood serum samples

1. Gas chromatographic measurement in water-steam circuits

International Nuclear Information System (INIS)

Zschetke, J.; Nieder, R.

1984-01-01

A gas chromatographic technique for measurements in water-steam circuits, which has been well known for many years, has been improved by design modifications. A new type of equipment developed for special measuring tasks on nuclear engineering plant also has a general application. To date measurements have been carried out on the ''Otto Hahn'' nuclear powered ship, on the KNK and AVR experimental nuclear power plants at Karlsruhe and Juelich respectively and on experimental boiler circuits. The measurements at the power plants were carried out under different operating conditions. In addition measurements during the alkali operating mode and during combined cycle operation were carried out on the AVR reactor. It has been possible to draw new conclusion from the many measurements undertaken. (orig.) [de

2. Demonstration of a 10 V programmable Josephson voltage standard system based on a multi-chip technique

Energy Technology Data Exchange (ETDEWEB)

Yamada, T; Sasaki, H; Yamamori, H; Shoji, A [National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568 (Japan)], E-mail: yamada-takahiro@aist.go.jp

2008-03-01

We have demonstrated a programmable Josephson voltage standard (PJVS) operation up to 10.84 V using a multi-chip technique. We combined two PJVS chips fabricated using NbN/(TiN{sub x}/NbN){sub 2} junction technology. Each PJVS chip was mounted on a single chip carrier using bonding wire, and the two chip carriers were connected by a simple Cu lead wire, and mounted on a cryocooler. High-precision measurements confirmed flat voltage steps for all 22 cells, with a peak-to-peak variation of 100 nV and wide margins of at least 0.35 mA. We also confirmed the stability of the voltage steps in spite of a temperature and RF frequency variation of {+-} 0.1 K and {+-} 0.1 GHz, respectively.

3. Late effects of craniospinal irradiation for standard risk medulloblastoma in paediatric patients: A comparison of treatment techniques

International Nuclear Information System (INIS)

Leman, J.

2016-01-01

Background: Survival rates for standard risk medulloblastoma are favourable, but craniospinal irradiation (CSI) necessary to eradicate microscopic spread causes life limiting late effects. Aims: The aim of this paper is to compare CSI techniques in terms of toxicity and quality of life for survivors. Methods and materials: A literature search was conducted using synonyms of ‘medulloblastoma’, ’craniospinal’, ‘radiotherapy’ and ‘side effects’ to highlight 29 papers that would facilitate this discussion. Results and discussion: Intensity modulated radiotherapy (IMRT), tomotherapy and protons all provide CSI which can reduce dose to normal tissue, however photon methods cannot eliminate exit dose as well as protons can. Research for each technique requires longer term follow up in order to prove that survival rates remain high whilst reducing late effects. Findings/conclusion: Proton therapy is the superior method of CSI in term of late effects, but more research is needed to evidence this. Until proton therapy is available in the UK IMRT should be utilised. - Highlights: • Craniospinal irradiation is vital in the treatment of medulloblastoma. • Survivors often suffer long term side effects which reduce quality of life. • Tomotherapy, IMRT and proton therapy reduce late effects by sparing normal tissue. • Proton therapy offers superior dose distribution but further research is necessary. • IMRT should be employed for photon radiotherapy.

4. Statistical modelling of measurement errors in gas chromatographic analyses of blood alcohol content.

Science.gov (United States)

Moroni, Rossana; Blomstedt, Paul; Wilhelm, Lars; Reinikainen, Tapani; Sippola, Erkki; Corander, Jukka

2010-10-10

Headspace gas chromatographic measurements of ethanol content in blood specimens from suspect drunk drivers are routinely carried out in forensic laboratories. In the widely established standard statistical framework, measurement errors in such data are represented by Gaussian distributions for the population of blood specimens at any given level of ethanol content. It is known that the variance of measurement errors increases as a function of the level of ethanol content and the standard statistical approach addresses this issue by replacing the unknown population variances by estimates derived from large sample using a linear regression model. Appropriate statistical analysis of the systematic and random components in the measurement errors is necessary in order to guarantee legally sound security corrections reported to the police authority. Here we address this issue by developing a novel statistical approach that takes into account any potential non-linearity in the relationship between the level of ethanol content and the variability of measurement errors. Our method is based on standard non-parametric kernel techniques for density estimation using a large database of laboratory measurements for blood specimens. Furthermore, we address also the issue of systematic errors in the measurement process by a statistical model that incorporates the sign of the error term in the security correction calculations. Analysis of a set of certified reference materials (CRMs) blood samples demonstrates the importance of explicitly handling the direction of the systematic errors in establishing the statistical uncertainty about the true level of ethanol content. Use of our statistical framework to aid quality control in the laboratory is also discussed. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

5. A hybrid electron and photon IMRT planning technique that lowers normal tissue integral patient dose using standard hardware.

Science.gov (United States)

Rosca, Florin

2012-06-01

To present a mixed electron and photon IMRT planning technique using electron beams with an energy range of 6-22 MeV and standard hardware that minimizes integral dose to patients for targets as deep as 7.5 cm. Ten brain cases, two lung, a thyroid, an abdominal, and a parotid case were planned using two planning techniques: a photon-only IMRT (IMRT) versus a mixed modality treatment (E+IMRT) that includes an enface electron beam and a photon IMRT portion that ensures a uniform target coverage. The electron beam is delivered using a regular cutout placed in an electron cone. The electron energy was chosen to provide a good trade-off between minimizing integral dose and generating a uniform, deliverable plan. The authors choose electron energies that cover the deepest part of PTV with the 65%-70% isodose line. The normal tissue integral dose, the dose for ring structures around the PTV, and the volumes of the 75%, 50%, and 25% isosurfaces were used to compare the dose distributions generated by the two planning techniques. The normal tissue integral dose was lowered by about 20% by the E+IMRT plans compared to the photon-only IMRT ones for most studied cases. With the exception of lungs, the dose reduction associated to the E+IMRT plans was more pronounced further away from the target. The average dose ratio delivered to the 0-2 cm and the 2-4 cm ring structures for brain patients for the two planning techniques were 89.6% and 70.8%, respectively. The enhanced dose sparing away from the target for the brain patients can also be observed in the ratio of the 75%, 50%, and 25% isodose line volumes for the two techniques, which decreases from 85.5% to 72.6% and further to 65.1%, respectively. For lungs, the lateral electron beams used in the E+IMRT plans were perpendicular to the mostly anterior/posterior photon beams, generating much more conformal plans. The authors proved that even using the existing electron delivery hardware, a mixed electron/photon planning

6. Determination of solute descriptors by chromatographic methods.

Science.gov (United States)

Poole, Colin F; Atapattu, Sanka N; Poole, Salwa K; Bell, Andrea K

2009-10-12

The solvation parameter model is now well established as a useful tool for obtaining quantitative structure-property relationships for chemical, biomedical and environmental processes. The model correlates a free-energy related property of a system to six free-energy derived descriptors describing molecular properties. These molecular descriptors are defined as L (gas-liquid partition coefficient on hexadecane at 298K), V (McGowan's characteristic volume), E (excess molar refraction), S (dipolarity/polarizability), A (hydrogen-bond acidity), and B (hydrogen-bond basicity). McGowan's characteristic volume is trivially calculated from structure and the excess molar refraction can be calculated for liquids from their refractive index and easily estimated for solids. The remaining four descriptors are derived by experiment using (largely) two-phase partitioning, chromatography, and solubility measurements. In this article, the use of gas chromatography, reversed-phase liquid chromatography, micellar electrokinetic chromatography, and two-phase partitioning for determining solute descriptors is described. A large database of experimental retention factors and partition coefficients is constructed after first applying selection tools to remove unreliable experimental values and an optimized collection of varied compounds with descriptor values suitable for calibrating chromatographic systems is presented. These optimized descriptors are demonstrated to be robust and more suitable than other groups of descriptors characterizing the separation properties of chromatographic systems.

7. Supercritical Fluid Chromatographic Separation of Dimethylpolysiloxane Polymer

Energy Technology Data Exchange (ETDEWEB)

Pyo, Dong Jin; Lim, Chang Hyun [Kangwon National University, Chuncheon (Korea, Republic of)

2005-02-15

Water was used as a polar modifier and a μ-porasil column as a saturator column. The μ-porasil column was inserted between the pump outlet and the injection valve. During the passage of the supercritical fluid mobile phase through the silica column, a polar modifier (water) can be dissolved in the pressurized supercritical fluid. Dimethylpolysiloxane polymer has been known as more polar polymer than polystyrene polymer. Dimethylpolysiloxane polymer has never been separated using water modified mobile phase. In this paper, using a μ-porasil column as a saturator column, excellent supercritical fluid chromatograms of dimethylpolysiloxane oligomers were obtained. The use of compressed (dense) gases and supercritical fluids as chromatographic mobile phases in conjunction with liquid chromatographic (LC)-type packed columns was first reported by Klesper et al. in 1962. During its relatively short history, supercritical fluid chromatography (SFC) has become an attractive alternative to GC and LC in certain industrially important applications. SFC gives the advantage of high efficiency and allows the analysis of nonvolatile or thermally labile mixtures.

8. Determination of solute descriptors by chromatographic methods

International Nuclear Information System (INIS)

Poole, Colin F.; Atapattu, Sanka N.; Poole, Salwa K.; Bell, Andrea K.

2009-01-01

The solvation parameter model is now well established as a useful tool for obtaining quantitative structure-property relationships for chemical, biomedical and environmental processes. The model correlates a free-energy related property of a system to six free-energy derived descriptors describing molecular properties. These molecular descriptors are defined as L (gas-liquid partition coefficient on hexadecane at 298 K), V (McGowan's characteristic volume), E (excess molar refraction), S (dipolarity/polarizability), A (hydrogen-bond acidity), and B (hydrogen-bond basicity). McGowan's characteristic volume is trivially calculated from structure and the excess molar refraction can be calculated for liquids from their refractive index and easily estimated for solids. The remaining four descriptors are derived by experiment using (largely) two-phase partitioning, chromatography, and solubility measurements. In this article, the use of gas chromatography, reversed-phase liquid chromatography, micellar electrokinetic chromatography, and two-phase partitioning for determining solute descriptors is described. A large database of experimental retention factors and partition coefficients is constructed after first applying selection tools to remove unreliable experimental values and an optimized collection of varied compounds with descriptor values suitable for calibrating chromatographic systems is presented. These optimized descriptors are demonstrated to be robust and more suitable than other groups of descriptors characterizing the separation properties of chromatographic systems.

9. Development, improvement and calibration of neutronic reaction rate measurements: elaboration of a base of standard techniques; Developpement, amelioration et calibration des mesures de taux de reaction neutroniques: elaboration dune base de techniques standards

Energy Technology Data Exchange (ETDEWEB)

Hudelot, J.P

1998-06-19

In order to improve and to validate the neutronic calculation schemes, perfecting integral measurements of neutronic parameters is necessary. This thesis focuses on the conception, the improvement and the development of neutronic reaction rates measurements, and aims at building a base of standard techniques. Two subjects are discussed. The first one deals with direct measurements by fission chambers. A short presentation of the different usual techniques is given. Then, those last ones are applied through the example of doubling time measurements on the EOLE facility during the MISTRAL 1 experimental programme. Two calibration devices of fission chambers are developed: a thermal column located in the central part of the MINERVE facility, and a calibration cell using a pulsed high flux neutron generator and based on the discrimination of the energy of the neutrons with a time-of-flight method. This second device will soon allow to measure the mass of fission chambers with a precision of about 1 %. Finally, the necessity of those calibrations will be shown through spectral indices measurements in core MISTRAL 1 (UO{sub 2}) and MISTRAL 2 (MOX) of the EOLE facility. In each case, the associated calculation schemes, performed using the Monte Carlo MCNP code with the ENDF-BV library, will be validated. Concerning the second one, the goal is to develop a method for measuring the modified conversion ratio of {sup 238}U (defined as the ratio of {sup 238}U capture rate to total fission rate) by gamma-ray spectrometry of fuel rods. Within the framework of the MISTRAL 1 and MISTRAL 2 programmes, the measurement device, the experimental results and the spectrometer calibration are described. Furthermore, the MCNP calculations of neutron self-shielding and gamma self-absorption are validated. It is finally shown that measurement uncertainties are better than 1 %. The extension of this technique to future modified conversion ratio measurements for {sup 242}Pu (on MOX rods) and

10. Expert training with standardized operative technique helps establish a successful penile prosthetics program for urologic resident education.

Science.gov (United States)

King, Ashley B; Klausner, Adam P; Johnson, Corey M; Moore, Blake W; Wilson, Steven K; Grob, B Mayer

2011-10-01

The challenge of resident education in urologic surgery programs is to overcome disparity imparted by diverse patient populations, limited training times, and inequalities in the availability of expert surgical educators. Specifically, in the area of prosthetic urology, only a small proportion of programs have full-time faculty available to train residents in this discipline. To examine whether a new model using yearly training sessions from a recognized expert can establish a successful penile prosthetics program and result in better outcomes, higher case volumes, and willingness to perform more complex surgeries. A recognized expert conducted one to two operative training sessions yearly to teach standardized technique for penile prosthetics to residents. Each session consisted of three to four operative cases performed under the direct supervision of the expert. Retrospective data were collected from all penile prosthetic operations before (February, 2000 to June, 2004: N = 44) and after (July, 2004 to October, 2007: N = 79) implementation of these sessions. Outcomes reviewed included patient age, race, medical comorbidities, operative time, estimated blood loss, type of prosthesis, operative approach, drain usage, length of stay, and complications including revision/explantation rates. Statistical analysis was performed using Student's t-tests, Fisher's tests, and survival curves using the Kaplan-Meier technique (P value ≤ 0.05 to define statistical significance). Patient characteristics were not significantly different pre- vs. post-training. Operative time and estimated blood loss significantly decreased. Inflatable implants increased from 19/44 (43.2%, pre-training) to 69/79 (87.3%, post-training) (P prosthetics surgery. © 2011 International Society for Sexual Medicine.

11. Should hand-assisted retroperitoneoscopic nephrectomy replace the standard laparoscopic technique for living donor nephrectomy? A meta-analysis.

Science.gov (United States)

Elmaraezy, Ahmed; Abushouk, Abdelrahman Ibrahim; Kamel, Moaz; Negida, Ahmed; Naser, Omar

2017-04-01

We performed this meta-analysis to compare hand-assisted retroperitoneoscopic (HARP) and traditional laparoscopic (TLS) techniques for living donor nephrectomy. We searched PubMed, Cochrane Central, EMBASE, and Web of science for prospective studies, comparing HARP and TLS techniques. Data were extracted from eligible studies and pooled as risk ratios (RR) or standardized mean difference (SMD), using RevMan software (version 5.3 for windows). We performed a sensitivity analysis to test the robustness of our evidence and a subgroup analysis to stratify intraoperative complications on Clavien-Dindo score. Seven studies (498 patients) were included in the final analysis. HARP was superior to TLS in terms of shortening the operative duration (SMD = -0.84, 95% CI [-1.18 to -0.50]) and warm ischemia time (SMD = -0.93, 95% CI [-1.13 to -0.72]). There was no significant difference between HARP and TLS in terms of blood loss (SMD = 0.13, 95% CI [-0.50 to 0.76]), hospital stay (SMD = -0.27, 95% CI [-0.70 to 0.15]) or graft survival (RR = 0.97, 95% CI [0.92 to 1.02]). The overall risk ratio of intraoperative complications did not differ significantly between the two groups (RR = 0.62, 95% CI [0.31 to 1.21]). Our meta-analysis shows that HARP was associated with a shorter surgery duration and less warm ischemia time than TLS. However, no significant differences were found between the two groups in terms of graft survival or intraoperative complication rates. We recommend HARP over TLS for living donor nephrectomy; however, future studies with larger sample sizes are recommended to compare both techniques in terms of operative safety and quality of life outcomes. Copyright © 2017 IJS Publishing Group Ltd. Published by Elsevier Ltd. All rights reserved.

12. Standard Test Method for Oxygen Content Using a 14-MeV Neutron Activation and Direct-Counting Technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2007-01-01

1.1 This test method covers the measurement of oxygen concentration in almost any matrix by using a 14-MeV neutron activation and direct-counting technique. Essentially, the same system may be used to determine oxygen concentrations ranging from over 50 % to about 10 g/g, or less, depending on the sample size and available 14-MeV neutron fluence rates. Note 1 - The range of analysis may be extended by using higher neutron fluence rates, larger samples, and higher counting efficiency detectors. 1.2 This test method may be used on either solid or liquid samples, provided that they can be made to conform in size, shape, and macroscopic density during irradiation and counting to a standard sample of known oxygen content. Several variants of this method have been described in the technical literature. A monograph is available which provides a comprehensive description of the principles of activation analysis using a neutron generator (1). 1.3 The values stated in either SI or inch-pound units are to be regarded...

13. Technique for evaluation of spatial resolution and microcalcifications in digital and scanned images of a standard breast phantom

International Nuclear Information System (INIS)

Santana, Priscila do C.; Gomes, Danielle S.; Oliveira, Marcio A.; Oliveira, Paulo Marcio C. de; Meira-Belo, Luiz C.; Nogueira-Tavares, Maria S.

2011-01-01

In this work, an automated methodology to evaluate digital and scanned images of a standard phantom (Phantom Mama) was studied. The Phantom Mama was used as an important tool to check the quality of mammographs. The scanned images were digitized using a ScanMaker 9800XL, with resolution of 900 dpi. The aim of this work is to test an automatic methodology for evaluation of spatial resolution and microcalcifications group of phantom mama images acquired with the same parameters in the same equipment. In order to analyze the images we have used the ImageJ software (in Java) which is public domain. We have used the Fast Fourier transform technique to evaluate the spatial resolution and used the ImageJ function Subtract Background and the Light Background plus Sliding Paraboloid on the evaluation of the five groups of microcalcifications on the breast phantom to assess the viability of using automated methods for both types of images. The methodology was adequate for evaluated the microcalcifications group and the spatial resolution in scanned and digital images, but the Phantom Mama doesn't provide sufficient parameters to evaluate the spatial resolution in this images. (author)

14. Gas-Chromatographic Determination Of Water In Freon PCA

Science.gov (United States)

Melton, Donald M.

1994-01-01

Gas-chromatographic apparatus measures small concentrations of water in specimens of Freon PCA. Testing by use of apparatus faster and provides greater protection against accidental contamination of specimens by water in testing environment. Automated for unattended operation. Also used to measure water contents of materials, other than Freon PCA. Innovation extended to development of purgeable sampling accessory for gas chromatographs.

15. Interface for liquid chromatograph-mass spectrometer

Science.gov (United States)

Andresen, Brian D.; Fought, Eric R.

1989-01-01

A moving belt interface for real-time, high-performance liquid chromatograph (HPLC)/mass spectrometer (MS) analysis which strips away the HPLC solvent as it emerges from the end of the HPLC column and leaves a residue suitable for mass-spectral analysis. The interface includes a portable, stand-alone apparatus having a plural stage vacuum station, a continuous ribbon or belt, a drive train magnetically coupled to an external drive motor, a calibrated HPLC delivery system, a heated probe tip and means located adjacent the probe tip for direct ionization of the residue on the belt. The interface is also capable of being readily adapted to fit any mass spectrometer.

16. Fast gas chromatographic separation of biodiesel.

Science.gov (United States)

Pauls, R E

2011-05-01

A high-speed gas chromatographic method has been developed to determine the FAME distribution of B100 biodiesel. The capillary column used in this work has dimensions of 20 m × 0.100 mm and is coated with a polyethylene glycol film. Analysis times are typically on the order of 4-5 min depending upon the composition of the B100. The application of this method to a variety of vegetable and animal derived B100 is demonstrated. Quantitative results obtained with this method were in close agreement with those obtained by a more conventional approach on a 100 m column. The method, coupled with solid-phase extraction, was also found suitable to determine the B100 content of biodiesel-diesel blends.

17. Chromatographic separation of rhenium in alumina-methanol/sulfuric acid system

International Nuclear Information System (INIS)

Oguma, Koichi

1983-01-01

The adsorption behavior of a number of metals on alumina was surveyed in a methanol-(0.005 -- 0.5) M H 2 SO 4 (3 : 1 v/v) developing solvent by thin-layer chromatography. Over the acid concentration range tested, Re(VII) does not favor the alumina phase to any great extent while the most other metals are strongly adsorbed on alumina. These findings allowed to establish a column chromatographic technique for selective separation of rhenium in a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) eluent. The separation technique thus established was applied to molybdenite analysis for rhenium. About 100-mg powdered sample containing ca. 100 ppm rhenium was decomposed with HNO 3 and then evaporated nearly to dryness. The residue was dissolved in NH 4 OH and the excess NH 4 OH was expelled by evaporation to dryness. The residue was dissolved in 2.5-ml 0.5 M H 2 SO 4 and 10-ml water, the insoluble materials filtered off, and the filtrate diluted to exactly 25 ml with water. A 10-ml aliquot of this solution was mixed with 30-ml methanol and the mixture was passed through a column (diameter 15 mm, bed height 30 mm) containing 5 g of alumina. The column was then washed with 20 ml of a methanol-0.05 M H 2 SO 4 (3 : 1 v/v) mixture. Rhenium was recovered from the loaded solution and the subsequent washings, and was determined spectrophotometrically with Methylene Blue as a chromogenic reagent. The values obtained from four samples of molybdenite are in good agreement with those obtained by neutron activation analysis. The relative standard deviation (n = 4; calculated from the range) was between 2.0 and 5.2 %. (author)

18. Quality evaluation of extracted ion chromatograms and chromatographic peaks in liquid chromatography/mass spectrometry-based metabolomics data.

Science.gov (United States)

Zhang, Wenchao; Zhao, Patrick X

2014-01-01

Extracted ion chromatogram (EIC) extraction and chromatographic peak detection are two important processing procedures in liquid chromatography/mass spectrometry (LC/MS)-based metabolomics data analysis. Most commonly, the LC/MS technique employs electrospray ionization as the ionization method. The EICs from LC/MS data are often noisy and contain high background signals. Furthermore, the chromatographic peak quality varies with respect to its location in the chromatogram and most peaks have zigzag shapes. Therefore, there is a critical need to develop effective metrics for quality evaluation of EICs and chromatographic peaks in LC/MS based metabolomics data analysis. We investigated a comprehensive set of potential quality evaluation metrics for extracted EICs and detected chromatographic peaks. Specifically, for EIC quality evaluation, we analyzed the mass chromatographic quality index (MCQ index) and propose a novel quality evaluation metric, the EIC-related global zigzag index, which is based on an EIC's first order derivatives. For chromatographic peak quality evaluation, we analyzed and compared six metrics: sharpness, Gaussian similarity, signal-to-noise ratio, peak significance level, triangle peak area similarity ratio and the local peak-related local zigzag index. Although the MCQ index is suited for selecting and aligning analyte components, it cannot fairly evaluate EICs with high background signals or those containing only a single peak. Our proposed EIC related global zigzag index is robust enough to evaluate EIC qualities in both scenarios. Of the six peak quality evaluation metrics, the sharpness, peak significance level, and zigzag index outperform the others due to the zigzag nature of LC/MS chromatographic peaks. Furthermore, using several peak quality metrics in combination is more efficient than individual metrics in peak quality evaluation.

19. Comparison of measured and calculated contralateral breast doses in whole breast radiotherapy for VMAT and standard tangent techniques

International Nuclear Information System (INIS)

Tse, T.L.J; Bromley, R.; Booth, J.; Gray, A.

2011-01-01

Full text: Objective This study aims to evaluate the accuracy of calculated dose with the Eclipse analytical anisotropic algorithm (AAA) for contralateral breast (CB) in left-sided breast radiotherapy for dual-arc VMA T and standard wedged tangent (SWT) techniques. Methods and materials Internal and surface CB doses were measured with EBT2 film in an anthropomorphic phantom mounted with C-cup and D-cup breasts. The measured point dose was approximated by averaging doses over the 4 x 4 mm 2 central region of each 2 x 2 cm2 piece of film. The dose in the target region of the breast was also measured. The measured results were compared to AAA calculations with calculation grids of I, 2.5 and 5 mm. Results In SWT plans, the average ratios of calculation to measurement for internal doses were 0.63 ± 0.081 and 0.5 I ± 0.28 in the medial and lateral aspects, respectively. Corresponding ratios for surface doses were 0.88 ± 0.22 and 0.38 ± 0.38. In VMAT plans, however, the calculation accuracies showed little dependence on the measurement locations, the ratios were 0.78 ± O. I I and 0.81 ± 0.085 for internal and surface doses. In general, finer calculation resolutions did not inevitably improve the dose estimates of internal doses. For surface doses, using smaller grid size I mm could improve the calculation accuracies on the medial but not the lateral aspects of CB. Conclusion In all plans, AAA had a tendency to underestimate both internal and surface CB doses. Overall, it produces more accurate results in VMAT than SWT plans.

20. Comparison of ankle-brachial index measured by an automated oscillometric apparatus with that by standard Doppler technique in vascular patients

DEFF Research Database (Denmark)

Korno, M.; Eldrup, N.; Sillesen, H.

2009-01-01

was calculated twice using both the methods on both legs. MATERIALS AND METHODS: We tested the automated oscillometric blood pressure device, CASMED 740, for measuring ankle and arm blood pressure and compared it with the current gold standard, the hand-held Doppler technique, by the Bland-Altman analysis....... RESULTS: Using the Doppler-derived ABI as the gold standard, the sensitivity and specificity of the oscillometric method for determining an ABI Udgivelsesdato: 2009/11...

1. Liquid chromatographic determination of benzo(a)pyrene in total particulate matter of cigarette smoke

Energy Technology Data Exchange (ETDEWEB)

Tomkins, B.A.; Jenkins, R.A.; Griest, W.H.; Reagan, R.R.; Holladay, S.K.

1985-09-01

The benzo(a)pyrene (BaP) delivery of reference and commercially available tobacco cigarettes, as well as reference and placebo marijuana cigarettes, is determined using a sequential liquid chromatographic/liquid chromatographic procedure. The total particulate matter of sample cigarette smoke is collected using a Cambridge filter pad, which is ultrasonically extracted with acetone. The resulting extract is filtered, then fractionated using semipreparative-scale normal phase liquid chromatography (LC). Quantitative determination is achieved using analytical-scale reverse phase LC equipped with a fluorescence detector. The method is precise (+/- 10-15% relative standard deviation) and yields 85% or better BaP recovery at the ng/cig. level. A single pad may be analyzed in 8 person-hours, while a more typical lot of 12 pads (6 pads each for 2 cigarette brands) may be analyzed in 10 person-days.

2. Liquid chromatographic determination of saccharin in beverages and desserts: complementary collaborative study.

Science.gov (United States)

Sjöberg, A M

1988-01-01

A complementary collaborative study was conducted on a liquid chromatographic method for determination of saccharin in accordance with the latest international recommendations. One industrial and 6 official food control laboratories analyzed 3 samples of a juice, a soft drink, and a dessert at concentration levels of 26-90 mg/L, 33-73 mg/L, and 56-147 mg/kg, respectively. Blind duplicates and a blank were supplied for each type of material at each concentration level. The beverage was chromatographed directly and the dessert was extracted with ethanol before chromatography. Average recoveries were 95-107%. The reproducibility relative standard deviations were 6.4-7.3% for the juice, 9.2-20.6% for the soft drink, and 13.4-16.2% for the dessert. The outlier percentage was 14.3%. The results were compared with those of an earlier collaborative study by Nordic laboratories and with general collaborative results obtained by AOAC.

3. Stereospecific high-performance liquid chromatographic assay of sotalol in plasma.

Science.gov (United States)

Carr, R A; Foster, R T; Bhanji, N H

1991-09-01

A convenient high-performance liquid chromatographic (HPLC) assay was developed for determination of sotalol (STL) enantiomers in plasma. Following addition of the internal standard (IS; racemic atenolol), enantiomers of STL and IS were extracted using ethyl acetate. After evaporation of the organic layer, samples were derivatized with a solution of S-(+)-1-(1-naphthyl)ethyl isocyanate (NEIC). The resulting diastereomers were chromatographed with normal-phase HPLC with chloroform:hexane:methanol [65:33:2 (v/v)] as the mobile phase at a flow rate of 2 ml/min. The fluorescence detection wavelength was set at 220 nm for excitation with no emission filter. The suitability of the assay for pharmacokinetic studies was determined by measuring STL enantiomers in the plasma of a healthy subject after administration of a single 160-mg oral, racemic dose of STL.

4. [Epidemics of schistosomiasis in military staff assigned to endemic areas: standard diagnostic techniques and the development of real-time PCR techniques].

Science.gov (United States)

Biance-Valero, E; De Laval, F; Delerue, M; Savini, H; Cheinin, S; Leroy, P; Soullié, B

2013-05-01

The authors report the results of molecular biology techniques for the early diagnosis of cases (invasion phase) of schistosomiasis during two epidemics occurring during French military projects in the Central African Republic and Madagascar. The use of these techniques in real time for subjects not residing in the endemic area significantly improves the sensitivity of screening. The attack rates of these episodes, according to a case definition that took positive specific PCR results into account, were 59% and 26%. These results are a concrete illustration of the proverb that "yaws begin where the trail stops".

5. Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

International Nuclear Information System (INIS)

Ying Liu

2004-01-01

My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

6. Chromatographic Separations of Enantiomers and Underivatized Oligosaccharides

Energy Technology Data Exchange (ETDEWEB)

Liu, Ying [Iowa State Univ., Ames, IA (United States)

2004-01-01

My graduate research has focused on separation science and bioanalytical analysis, which emphasized in method development. It includes three major areas: enantiomeric separations using high performance liquid chromatography (HPLC), Super/subcritical fluid chromatography (SFC), and capillary electrophoresis (CE); drug-protein binding behavior studies using CE; and carbohydrate analysis using liquid chromatograph-electrospray ionization mass spectrometry (LC-ESI-MS). Enantiomeric separations continue to be extremely important in the pharmaceutical industry. An in-depth evaluation of the enantiomeric separation capabilities of macrocyclic glycopeptides CSPs with SFC mobile phases was investigated using a set of over 100 chiral compounds. It was found that the macrocyclic based CSPs were able to separate enantiomers of various compounds with different polarities and functionalities. Seventy percent of all separations were achieved in less than 4 min due to the high flow rate (4.0 ml/min) that can be used in SFC. Drug-protein binding is an important process in determining the activity and fate of a drug once it enters the body. Two drug/protein systems have been studied using frontal analysis CE method. More sensitive fluorescence detection was introduced in this assay, which overcame the problem of low sensitivity that is common when using UV detection for drug-protein studies. In addition, the first usage of an argon ion laser with 257 nm beam coupled with CCD camera as a frontal analysis detection method enabled the simultaneous observation of drug fluorescence as well as the protein fluorescence. LC-ESI-MS was used for the separation and characterization of underivatized oligosaccharide mixtures. With the limits of detection as low as 50 picograms, all individual components of oligosaccharide mixtures (up to 11 glucose-units long) were baseline resolved on a Cyclobond I 2000 column and detected using ESI-MS. This system is characterized by high chromatographic

7. Quantitative Mass spectrometric Analysis of Ropivacaine and Bupivacaine in Authentic, Pharmaceutical and Spiked Human Plasma without Chromatographic Separation

Directory of Open Access Journals (Sweden)

Nahla N. Salama

2009-01-01

Full Text Available The present study employs time of flight mass spectrometry for quantitative analysis of the local anesthetic drugs ropivacaine and bupivacaine in authentic, pharmaceutical and spiked human plasma as well as in the presence of their impurities 2,6-dimethylaniline and alkaline degradation product. The method is based on time of flight electron spray ionization mass spectrometry technique without preliminary chromatographic separation and makes use of bupivacaine as internal standard for ropivacaine, which is used as internal standard for bupivacaine. A linear relationship between drug concentrations and the peak intensity ratio of ions of the analyzed substances is established. The method is linear from 23.8 to 2380.0 ng mL-1 for both drugs. The correlation coefficient was ≥0.996 in authentic and spiked human plasma. The average percentage recoveries in the ranges of 95.39%–102.75% was obtained. The method is accurate (% RE < 5% and reproducible with intra- and inter-assay precision (RSD% < 8.0%. The quantification limit is 23.8 ng mL-1 for both drugs. The method is not only highly sensitive and selective, but also simple and effective for determination or identification of both drugs in authentic and biological fluids. The method can be applied in purity testing, quality control and stability monitoring for the studied drugs.

8. Quantitative Mass Spectrometric Analysis of Ropivacaine and Bupivacaine in Authentic, Pharmaceutical and Spiked Human Plasma without Chromatographic Separation

Directory of Open Access Journals (Sweden)

Nahla N. Salama

2009-01-01

Full Text Available The present study employs time of flight mass spectrometry for quantitative analysis of the local anesthetic drugs ropivacaine and bupivacaine in authentic, pharmaceutical and spiked human plasma as well as in the presence of their impurities 2,6-dimethylaniline and alkaline degradation product. The method is based on time of flight electron spray ionization mass spectrometry technique without preliminary chromatographic separation and makes use of bupivacaine as internal standard for ropivacaine, which is used as internal standard for bupivacaine. A linear relationship between drug concentrations and the peak intensity ratio of ions of the analyzed substances is established. The method is linear from 23.8 to 2380.0 ng mL −1 for both drugs. The correlation coefficient was ≥0.996 in authentic and spiked human plasma. The average percentage recoveries in the ranges of 95.39%-102.75% was obtained. The method is accurate (% RE <; 5% and reproducible with intra- and inter-assay precision (RSD% <; 8.0%. The quantification limit is 23.8 ng mL −1 for both drugs. The method is not only highly sensitive and selective, but also simple and effective for determination or identification of both drugs in authentic and biological fluids. The method can be applied in purity testing, quality control and stability monitoring for the studied drugs.

9. Chromatographic Separation of Vitamin E Enantiomers

Directory of Open Access Journals (Sweden)

Ju-Yen Fu

2017-02-01

Full Text Available Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.

10. Method for chromatographically recovering scandium and yttrium

International Nuclear Information System (INIS)

Snyder, T.S.; Stoltz, R.A.

1991-01-01

This paper describes a method for chromatographically recovering scandium and yttrium from the residue of a sand chlorinator. It comprises: providing a residue from a sand chlorinator, the residue containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; digesting the residue with an acid to produce an aqueous liquid containing scandium, yttrium, sodium, calcium and at least one radioactive metal of the group consisting of radium, thorium and uranium; feeding the metal containing liquid through a cation exchanger; eluding the cation exchanger with an acid eluant to to produce: a first eluate containing at least half of the total weight of the calcium and sodium in the feed liquid; a second eluate containing at least half of the total weight of the one or more radioactive metals in the feed liquid; a third eluate containing at least half of the yttrium in the feed liquid, and a fourth eluate containing at least half of the weight of the scandium in the feed liquid

11. Chromatographic methods of the measurements of the chloride compounds in troposphere and stratosphere

International Nuclear Information System (INIS)

Lasa, J.; Rosiek, J.

1992-01-01

The paper contains a description of various chromatographic techniques used for the analysis of the tropospheric techniques used for the analysis of the tropospheric and stratospheric halogenated compounds. The types of the column packings used for separation of halogenated compounds are described. Model chromatograms illustrating the separation of halogenated compounds are presented. The methods of the air sampling and injection for the packed and capillary columns were described. The methods of the preparation of gas calibration mixtures are presented. Operational conditions for electron capture detector used by the authors of quoted paper are also given. (author). 66 refs, 29 figs, 13 tabs

12. Improvement of security techniques and protection of biometric data in biometric systems: Presentation of International Standard ISO 24745

OpenAIRE

2017-01-01

This paper presents the International Standard ISO 24745 as a potential security tool for biometric information protection, more precisely as a tool for privacy protection in biometric systems. This is one of the latest internationally accepted standards that address the security issues of biometric systems.

13. High performance liquid chromatographic determination of glucosamine in rat plasma.

Science.gov (United States)

Aghazadeh-Habashi, Ali; Sattari, Saeed; Pasutto, Franco; Jamali, Fakhreddin

2002-01-01

A high performance liquid chromatographic method was developed for the determination of glucosamine (GlcN) in rat plasma. Internal standard, galactosamine, was added to 100 micro L of plasma containing GlcN followed by precipitation of plasma proteins with acetonitrile. Evaporation of the decanted supernatant solution was accelerated by the addition of methanol. GlcN was derivatized by addition of a solution containing 1-naphthyl isothiocyanate. Sample cleanup included passage through an anion exchange cartridge. Analysis was accomplished by injection of 0.1 mL of the sample solution into an isocratic HPLC system consisting of a C18 column, a mobile phase of acetonitrile: water: acetic acid: triethylamine (4.5: 95.5:0.1:0.05), a flow rate of 0.9 mL/min, and a UV detector set at 254 nm. Galactosamine and GlcN appeared 26 and 29 min post-injection, respectively. The assay was linear over the range of 1.25-400 micro g/mL (CV<10%) with a detection limit of 0.63 microg/mL and a limit of quantification of 1.25 microg/mL. The method was applied to the determination of GlcN in rat plasma after oral administration of 350 mg/kg of GlcN hydrochloride. The present assay is specific, sensitive, precise, and accurate and is suitable for pharmacokinetic studies.

14. Chromatographic and electrophoretic methods for nanodisc purification and analysis

DEFF Research Database (Denmark)

Justesen, Bo Højen; Günther-Pomorski, Thomas

2014-01-01

of proper reconstitution are still major challenges during the sample preparation. This review gives an overview of the methods used for purifying and analyzing nanodiscs and nanodisc-reconstituted membrane proteins, with an emphasis on the chromatographic and electrophoretic approaches....

15. Evaluation of pesticide adsorption in gas chromatographic injector and column

Directory of Open Access Journals (Sweden)

Gevany Paulino de Pinho

2012-01-01

Full Text Available Components in complex matrices can cause variations in chromatographic response during analysis of pesticides by gas chromatography. These variations are related to the competition between analytes and matrix components for adsorption sites in the chromatographic system. The capacity of the pesticides chlorpyrifos and deltamethrin to be adsorbed in the injector and chromatographic column was evaluated by constructing three isotherms and changing the column heating rate to 10 and 30 ºC min-1. By using ANCOVA to compare the slope of calibration graphs, results showed that the higher the injector temperature (310 ºC the lower the pesticide adsorption. Also, deltamethrin influenced the adsorption of chlorpyrifos on the column chromatographic.

16. Approaches to characterise chromatographic column performance based on global parameters accounting for peak broadening and skewness.

Science.gov (United States)

Baeza-Baeza, J J; Pous-Torres, S; Torres-Lapasió, J R; García-Alvarez-Coque, M C

2010-04-02

Peak broadening and skewness are fundamental parameters in chromatography, since they affect the resolution capability of a chromatographic column. A common practice to characterise chromatographic columns is to estimate the efficiency and asymmetry factor for the peaks of one or more solutes eluted at selected experimental conditions. This has the drawback that the extra-column contributions to the peak variance and skewness make the peak shape parameters depend on the retention time. We propose and discuss here the use of several approaches that allow the estimation of global parameters (non-dependent on the retention time) to describe the column performance. The global parameters arise from different linear relationships that can be established between the peak variance, standard deviation, or half-widths with the retention time. Some of them describe exclusively the column contribution to the peak broadening, whereas others consider the extra-column effects also. The estimation of peak skewness was also possible for the approaches based on the half-widths. The proposed approaches were applied to the characterisation of different columns (Spherisorb, Zorbax SB, Zorbax Eclipse, Kromasil, Chromolith, X-Terra and Inertsil), using the chromatographic data obtained for several diuretics and basic drugs (beta-blockers). Copyright (c) 2010 Elsevier B.V. All rights reserved.

17. Response surface based optimization of system variables for liquid chromatographic analysis of candesartan cilexetil

Directory of Open Access Journals (Sweden)

Jagdish V. Manwar

2017-01-01

Full Text Available A statistical optimization method was successfully employed to study the effect of system variables on the chromatographic analysis of candesartan cilexetil. The effect of simultaneously varying the flow rate, temperature and concentration of acetonitrile in the mobile phase in water (0.05% O-phosphoric acid (0.05% OPA was studied to optimize the method to obtain excellent chromatographic responses. The optimum conditions were determined with the help of response surface methodology (RSM using Plackett–Burman designs. From the response surface graphs, the optimum regions were selected to be −1, +1 and +1 for flow rate (0.8 ml/min, temperature (25 °C and concentration of acetonitrile in water (0.05% OPA (80%, v/v, respectively. Pareto ranking indicated that the most important variable affecting the selected responses was temperature. Linearity was found in the range of 10 of 50 μg/ml, with a significantly high correlation coefficient (r2 = 0.9989. The limits of detection and quantitation were 0.12 and 0.33 μg/ml, respectively. The developed method was validated for accuracy, precision, linearity, range, and specificity. The method was successfully used to analyze a tablet formulation to assess the chromatographic performance, and it was found to be 99.03%, with a standard deviation of ±0.04.

18. Comparison of thin layer chromatographic and gas chromatographic determination of propoxur residues in a cocoa ecosystem

International Nuclear Information System (INIS)

Yeboah, P.O.; Lowor, S.; Akpabli, C.K.

2005-01-01

The fate of propoxur in a cocoa ecosystem has been studied using thin layer chromatographic (TLC) and gas chromatographic (GC) methods. Residues of propoxur as determined by both TLC and GC were not significantly different. TLC analysis of propoxur residues in soil, cocoa leaves and pods did not require any rigorous cleanup since residues measured from cleaned extracts and without cleanup were not significantly different. The residue levels of propoxur in the soil were found to decrease rapidly and, by the 21st day, none was detected in the topsoil (0-15 cm). Evidence of leaching of propoxur residues in the soil has also been demonstrated. The amount left in the top soil after the first seven days were 27%, 23% and 24% of the initial one as determined by the TLC without cleanup, TLC with cleanup and GLC, respectively. No propoxur residue was detected in topsoil 21 days after spraying. About 38% of pesticides detected on the cocoa pod on the day of treatment remained on the pod seven days after treatment. The residue detected on the leaves on the day of treatment was higher than that in or on the soil. This decreased rapidly to 1.7% in 21 days compared to 16% for the soil and 23% for the pod. (author)

19. Thermodynamic vs. extrathermodynamic modeling of chromatographic retention.

Science.gov (United States)

Kaliszan, Roman; Wiczling, Paweł; Markuszewski, Michał J; Al-Haj, Mehdi A

2011-08-05

To predict a given physicochemical or biological property, and hence, to design rationally requested chemical entity, the relationships must be identified between the chemical structure and the desired property. Unfortunately, classical thermodynamics never predicts any property by itself, even so simple one like chromatographic retention. Therefore progress in understanding and describing molecular equilibrium between phases requires a combination of experimental measurements and correlations by means of empirical equations and approximate theories. In this work the retention prediction performance was tested of the well thermodynamically founded solvophobic theory of Horváth and co-workers of reversed-phase HPLC. The retention parameters of four series of analytes were modeled with regard to their chemical structure by: (1) observing the rules of classical thermodynamics; (2) applying an extrathermodynamically derived correction to the model based on the thermodynamic hermeneutics; (3) using extrathermodynamic, chemical intuition-based Quantitative Structure-Retention Relationships (QSRR). The combined thermodynamic/extrathermodynamic model with empirical correction accounting for the number of polar atoms provided an improvement of the agreement between the observed and the predicted retention parameters. However, a purely extrathermodynamic QSRR model, employing analyte descriptors from calculation chemistry, produced similar retention predictions. Both thermodynamic and QSRR models accounted well for abilities of analyte to participate in nonspecific, dispersive intermolecular interactions. Less reliable appeared descriptors of analyte polarity. The approach presented here can be further developed to search for proper polarity parameters, necessary to correctly predict complex physicochemical and biological properties of chemical compounds. Copyright © 2011 Elsevier B.V. All rights reserved.

20. Duration of Hemodialysis Following Peritoneal Dialysis Cessation in Australia and New Zealand: Proposal for a Standardized Definition of Technique Failure.

Science.gov (United States)

Lan, Patrick G; Clayton, Philip A; Johnson, David W; McDonald, Stephen P; Borlace, Monique; Badve, Sunil V; Sud, Kamal; Boudville, Neil

♦ BACKGROUND: Although technique failure is a key outcome in peritoneal dialysis (PD), there is currently no agreement on a uniform definition. We explored different definitions of PD technique failure using data from the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. ♦ METHODS: We included 16,612 incident PD patients in Australia and New Zealand from January 1998 to December 2012. Different definitions of technique failure were applied according to the minimum number of days (30, 60, 90, 180, or 365) the patient received hemodialysis after cessation of PD. ♦ RESULTS: Median technique survival varied from 2.0 years with the 30-day definition to 2.4 years with the 365-day definition. For all definitions, the most common causes of technique failure were death, followed by infectious complications. The likelihood of a patient returning to PD within 12 months of technique failure was highest in the 30-day definition (24%), and was very small when using the 180- and 365-day definitions (3% and 0.8%, respectively). Patients whose technique failed due to mechanical reasons were the most likely to return to PD (46% within 12 months using the 30-day definition). ♦ CONCLUSIONS: Both 30- and 180-day definitions have clinical relevance but offer different perspectives with very different prognostic implications for further PD. Therefore, we propose that PD technique failure be defined by a composite endpoint of death or transfer to hemodialysis using both 30-day and 180-day definitions. Copyright © 2016 International Society for Peritoneal Dialysis.

1. Chromatographic fingerprinting: An innovative approach for food 'identitation' and food authentication - A tutorial.

Science.gov (United States)

2016-02-25

Fingerprinting methods describe a variety of analytical methods that provide analytical signals related to the composition of foodstuffs in a non-selective way such as by collecting a spectrum or a chromatogram. Mathematical processing of the information in such fingerprints may allow the characterisation and/or authentication of foodstuffs. In this context, the particular meaning of 'fingerprinting', in conjunction with 'profiling', is different from the original meanings used in metabolomics. This fact has produced some confusion with the use of these terms in analytical papers. Researchers coming from the metabolomic field could use 'profiling' or 'fingerprinting' on a different way to researchers who are devoted to food science. The arrival of an eclectic discipline, named 'foodomics' has not been enough to allay this terminological problem, since the authors keep on using the terms with both meanings. Thus, a first goal of this tutorial is to clarify the difference between both terms. In addition, the chemical approaches for food authentication, i.e., chemical markers, component profiling and instrumental fingerprinting, have been described. A new term, designated as 'food identitation', has been introduced in order to complete the life cycle of the chemical-based food authentication process. Chromatographic fingerprinting has been explained in detail and some strategies which could be applied has been clarified and discussed. Particularly, the strategies for chromatographic signals acquisition and chromatographic data handling are unified in a single framework. Finally, an overview about the applications of chromatographic (GC and LC) fingerprints in food authentication using different chemometric techniques has been included. Copyright © 2016 Elsevier B.V. All rights reserved.

2. Unreamed intramedullary nailing of femoral shaft fractures: operative technique and early clinical experience with the standard locking option.

Science.gov (United States)

Krettek, C; Rudolf, J; Schandelmaier, P; Guy, P; Könemann, B; Tscherne, H

1996-05-01

Nailing techniques have changed in recent years in ways which are not just limited to omitting the reaming process. These changes concern positioning patients, techniques of reduction and selecting implants. Techniques of approach and exposure have been modified to new, less-invasive procedures to fulfill technical, functional and cosmetic requirements. In addition, techniques have been developed to avoid fragment diastasis, rotational and sagittal malalignment, and leg-length discrepancy. Finally, simple algorithms have been elaborated for the management of specific fracture patterns (bilateral shaft fractures, ipsilateral tibial fractures or associated femoral neck fractures) and to determine the number and location of locking bolts. We developed these algorithms, techniques and procedures in a series of 133 femoral shafts, which were stabilized with the AO unreamed femoral nail (URFN) in a prospective study between 1991 and 1994. Of these, the first 57 cases with a mean follow-up of 17.9 months (range, 5-44) after injury were reviewed. Fractures were classified according to Müller's 1990 system: 12 type A, 29 type B and 16 type C. Closed soft-tissue injuries were classified by our classification of 1982: 17 type C 0/I, 42 type C II. Of 15 open fractures, six were OI, six OII, two OIIIA and one was OIIIB by Gustilo's classification of 1984. The major complications were two broken locking bolts, one nail breaking after 9 weeks, one case of osteitis and one of intra-operative lung embolism.

3. Validated electrochemical and chromatographic quantifications of some antibiotic residues in pharmaceutical industrial waste water.

Science.gov (United States)

Ibrahim, Heba K; Abdel-Moety, Mona M; Abdel-Gawad, Sherif A; Al-Ghobashy, Medhat A; Kawy, Mohamed Abdel

2017-03-01

Realistic implementation of ion selective electrodes (ISEs) into environmental monitoring programs has always been a challenging task. This could be largely attributed to difficulties in validation of ISE assay results. In this study, the electrochemical response of amoxicillin trihydrate (AMX), ciprofloxacin hydrochloride (CPLX), trimethoprim (TMP), and norfloxacin (NFLX) was studied by the fabrication of sensitive membrane electrodes belonging to two types of ISEs, which are polyvinyl chloride (PVC) membrane electrodes and glassy carbon (GC) electrodes. Linear response for the membrane electrodes was in the concentration range of 10 -5 -10 -2  mol/L. For the PVC membrane electrodes, Nernstian slopes of 55.1, 56.5, 56.5, and 54.0 mV/decade were achieved over a pH 4-8 for AMX, CPLX, and NFLX, respectively, and pH 3-6 for TMP. On the other hand, for GC electrodes, Nernstian slopes of 59.1, 58.2, 57.0, and 58.2 mV/decade were achieved over pH 4-8 for AMX, CPLX, and NFLX, respectively, and pH 3-6 for TMP. In addition to assay validation to international industry standards, the fabricated electrodes were also cross-validated relative to conventional separation techniques; high performance liquid chromatography (HPLC), and thin layer chromatography (TLC)-densitometry. The HPLC assay was applied in concentration range of 0.5-10.0 μg/mL, for all target analytes. The TLC-densitometry was adopted over a concentration range of 0.3-1.0 μg/band, for AMX, and 0.1-0.9 μg/band, for CPLX, NFLX, and TMP. The proposed techniques were successfully applied for quantification of the selected drugs either in pure form or waste water samples obtained from pharmaceutical plants. The actual waste water samples were subjected to solid phase extraction (SPE) for pretreatment prior to the application of chromatographic techniques (HPLC and TLC-densitometry). On the other hand, the fabricated electrodes were successfully applied for quantification of the antibiotic residues in actual

4. Ten years of experience in extraction chromatographic processes for the recovery, separation and purification of actinides elements

International Nuclear Information System (INIS)

Madic, C.; Bourges, J.; Koehly, G.

1984-06-01

Ten years ago the extraction chromatographic technique was developed for preparative purposes and is now applied for all chemicals separations needed for the production of actinides isotopes. That technique appears to be simple and flexible. It can be used for the production of microgram to kilogram amounts of actinide isotopes. This paper focuses on the experience gained and describes some peculiar production of actinide isotopes solved by using extraction chromatographic technique. After a review of extracting molecules and equipment, treatment of irradiated targets (preparation of Pu 238 and removal of neptunium, production of Am 243 and Cm 244), recovery of actinides from alpha aqueous wastes (preparation of Am 241) and recovery of decay products from aged actinide stocks (recovery of Am 241 from Pu stocks, of U 234 from Pu 238 stocks) are described

5. A Technique for Standardized Evaluation of Soft and Hard Peri-Implant Tissues in Partially Edentulous Patients

NARCIS (Netherlands)

Meijndert, Leo; Meijer, Henny J.A.; Raghoebar, Gerry M.; Vissink, Arjan

Background: There is a growing need to evaluate the esthetics of implant-supported crowns and bridges. An important tool for such an evaluation is standardized assessment of the soft and hard peri-implant tissue levels. Methods: A simple acrylic device has been developed for reliable and

6. Slit-scanning technique using standard cell sorter instruments for analyzing and sorting nonacrocentric human chromosomes, including small ones

NARCIS (Netherlands)

Rens, W.; van Oven, C. H.; Stap, J.; Jakobs, M. E.; Aten, J. A.

1994-01-01

We have investigated the performance of two types of standard flow cell sorter instruments, a System 50 Cytofluorograph and a FACSTar PLUS cell sorter, for the on-line centromeric index (CI) analysis of human chromosomes. To optimize the results, we improved the detection efficiency for centromeres

7. Fundamental studies of chalcogenide nanocrystals, carbonaceous nanoparticles, and chromatographic materials

Science.gov (United States)

Baker, Jared Scott

2011-12-01

The development of novel nanomaterials and the understanding of their fundamental physical and chemical properties represent an exciting area of research. These materials are continuously being sought for ever-increasing applications; finding their way into uses that influence mankind on a daily basis. Combining elements from traditional nanoparticle characterization with electrophoretic-based techniques, this dissertation presents the analysis of carbon nanoparticles (CNPs) generated from a novel source (candle soot) as well as a unique perspective on the reactivity and degradation process of magic-sized cadmium chalcogenide nanocrystals. One potential application of CNPs is their use as an alternative fluorophore in a separation-based sensor system. Laser-induced-fluorescence (LIF) is a commonly used manner of detection in this type of platform, but is limited in many cases by problems associated with the fluorophore. Carbon-based nanoparticles have the potential to improve upon traditional fluorophores in applications that make use of LIF as the detection scheme. CNPs were extracted from the carbonaceous material produced by the incomplete combustion of a candle. The soot was submitted to an oxidizing treatment and extraction/filtration procedures rendering watersoluble luminescent species. Electron microscopy was used to identify globular, amorphous structures in the nanometer size-range. An aqueous suspension of CNPs demonstrated excellent stability in terms of its electronic properties, showing little change in absorption and emission spectra upon storage under ambient conditions over a two-year period. Capitalizing on the strengths of capillary electrophoresis (CE) as a characterization technique, we have analyzed the negatively-charged CNPs in terms of charge and size by studying the influence of variable CE conditions on the resulting separation. Separations at different pH revealed a highly complex mixture of CNPs, containing species with large

8. Chromatographic 188W →188Re generator

International Nuclear Information System (INIS)

Khujaev, S.

2005-01-01

9. Strain analysis in CRT candidates using the novel segment length in cine (SLICE) post-processing technique on standard CMR cine images.

Science.gov (United States)

Zweerink, Alwin; Allaart, Cornelis P; Kuijer, Joost P A; Wu, LiNa; Beek, Aernout M; van de Ven, Peter M; Meine, Mathias; Croisille, Pierre; Clarysse, Patrick; van Rossum, Albert C; Nijveldt, Robin

2017-12-01

Although myocardial strain analysis is a potential tool to improve patient selection for cardiac resynchronization therapy (CRT), there is currently no validated clinical approach to derive segmental strains. We evaluated the novel segment length in cine (SLICE) technique to derive segmental strains from standard cardiovascular MR (CMR) cine images in CRT candidates. Twenty-seven patients with left bundle branch block underwent CMR examination including cine imaging and myocardial tagging (CMR-TAG). SLICE was performed by measuring segment length between anatomical landmarks throughout all phases on short-axis cines. This measure of frame-to-frame segment length change was compared to CMR-TAG circumferential strain measurements. Subsequently, conventional markers of CRT response were calculated. Segmental strains showed good to excellent agreement between SLICE and CMR-TAG (septum strain, intraclass correlation coefficient (ICC) 0.76; lateral wall strain, ICC 0.66). Conventional markers of CRT response also showed close agreement between both methods (ICC 0.61-0.78). Reproducibility of SLICE was excellent for intra-observer testing (all ICC ≥0.76) and good for interobserver testing (all ICC ≥0.61). The novel SLICE post-processing technique on standard CMR cine images offers both accurate and robust segmental strain measures compared to the 'gold standard' CMR-TAG technique, and has the advantage of being widely available. • Myocardial strain analysis could potentially improve patient selection for CRT. • Currently a well validated clinical approach to derive segmental strains is lacking. • The novel SLICE technique derives segmental strains from standard CMR cine images. • SLICE-derived strain markers of CRT response showed close agreement with CMR-TAG. • Future studies will focus on the prognostic value of SLICE in CRT candidates.

10. Strain analysis in CRT candidates using the novel segment length in cine (SLICE) post-processing technique on standard CMR cine images

Energy Technology Data Exchange (ETDEWEB)

Zweerink, Alwin; Allaart, Cornelis P.; Wu, LiNa; Beek, Aernout M.; Rossum, Albert C. van; Nijveldt, Robin [VU University Medical Center, Department of Cardiology, and Institute for Cardiovascular Research (ICaR-VU), Amsterdam (Netherlands); Kuijer, Joost P.A. [VU University Medical Center, Department of Physics and Medical Technology, Amsterdam (Netherlands); Ven, Peter M. van de [VU University Medical Center, Department of Epidemiology and Biostatistics, Amsterdam (Netherlands); Meine, Mathias [University Medical Center, Department of Cardiology, Utrecht (Netherlands); Croisille, Pierre; Clarysse, Patrick [Univ Lyon, UJM-Saint-Etienne, INSA, CNRS UMR 5520, INSERM U1206, CREATIS, Saint-Etienne (France)

2017-12-15

Although myocardial strain analysis is a potential tool to improve patient selection for cardiac resynchronization therapy (CRT), there is currently no validated clinical approach to derive segmental strains. We evaluated the novel segment length in cine (SLICE) technique to derive segmental strains from standard cardiovascular MR (CMR) cine images in CRT candidates. Twenty-seven patients with left bundle branch block underwent CMR examination including cine imaging and myocardial tagging (CMR-TAG). SLICE was performed by measuring segment length between anatomical landmarks throughout all phases on short-axis cines. This measure of frame-to-frame segment length change was compared to CMR-TAG circumferential strain measurements. Subsequently, conventional markers of CRT response were calculated. Segmental strains showed good to excellent agreement between SLICE and CMR-TAG (septum strain, intraclass correlation coefficient (ICC) 0.76; lateral wall strain, ICC 0.66). Conventional markers of CRT response also showed close agreement between both methods (ICC 0.61-0.78). Reproducibility of SLICE was excellent for intra-observer testing (all ICC ≥0.76) and good for interobserver testing (all ICC ≥0.61). The novel SLICE post-processing technique on standard CMR cine images offers both accurate and robust segmental strain measures compared to the 'gold standard' CMR-TAG technique, and has the advantage of being widely available. (orig.)

11. Direct chromatographic methods for the rapid determination of homogentisic acid in strawberry tree (Arbutus unedo L.) honey.

Science.gov (United States)

Scanu, Roberta; Spano, Nadia; Panzanelli, Angelo; Pilo, Maria I; Piu, Paola C; Sanna, Gavino; Tapparo, Andrea

2005-10-07

Two rapid and direct chromatographic methods based on reverse phase-high performance liquid chromatography (RP-HPLC) and ion chromatography (IC) were developed for the determination of homogentisic acid (HA) in honey. This is the marker of the botanic origin of strawberry tree honey. The methods were validated and tested using 22 samples from Sardinia, Italy. The IC method is faster than the RP-HPLC one (6 min versus 13 min of total run), but it is slightly less sensitive (the limit of detection (LOD), is 26 mg kg(-1) versus 15 mg kg(-1)) and reproducible (relative standard deviation, RSD, of 10.4 and 4.4%, respectively). The whole dataset of validation parameters allows both the proposed methods to be considered as bias-free (by recovery tests, comparison of analytical results of the two independent methods and analysis of a synthetic sample) and precise (both the techniques show a repeatability better than 2% repeatability in the range between 70 and 600 mg kg(-1)).

12. Dynamic Headspace Sampling as an Initial Step for Sample Preparation in Chromatographic Analysis.

Science.gov (United States)

Wojnowski, Wojciech; Majchrzak, Tomasz; Dymerski, Tomasz; Gębicki, Jacek; Namieśnik, Jacek

2017-11-01

This work represents a brief summary of the use of dynamic headspace (DHS) as a technique for sample preparation in chromatographic analysis. Despite numerous developments in the area of analyte isolation and enrichment, DHS remains one of the fundamental methods used with GC. In our opinion, interest in this technique will not diminish significantly because it conforms to stipulations of green analytical chemistry. Moreover, DHS fulfills the need for methods that facilitate detection and determination of analytes present at ultratrace levels in complex matrixes. The main focus of this work was placed on the theoretical fundamentals of this method. Also described herein were DHS development, the advantages and disadvantages of this technique compared with other headspace sampling techniques, and selected examples of its applications in food and environmental analyses.

13. A Simple and Rapid Extraction for Gas Chromatographic Determination of Thiabendazole and Imazalil Residues in Lemons

Directory of Open Access Journals (Sweden)

Navickiene Sandro

2002-01-01

Full Text Available A rapid and efficient method is described for the determination of thiabendazole and imazalil residues in lemons (peel and pulp. The procedure is based on the extraction with an hexane:ethyl acetate mixture (1:1, v/v and gas chromatographic analysis using thermionic specific detection (TSD. The possibility of matrix effect was also studied. Mean recoveries from 8 replicates of fortified samples ranged from 79% to 109%, with relative standard deviation values between 2.4% to 12.8%. The detection and quantification limits of the method were 0.2 mg kg-1 and 0.5 mg kg-1, respectively.

14. Chemical Separation Technique of Strontium-90 in the Soil Water as theStandard Methods for Environmental Radioactivity Analysis

International Nuclear Information System (INIS)

Ngasifudin-Hamdani; Suratman; Djoko-Sardjono, Ign; Winduanto-Wahyu SP

2000-01-01

Research about separation technique of strontium-90 from its materialmatrix using chemical precipitation method has been done. That technique wasapplied on the detection of radionuclide strontium-90 containing in the soilwater of near nuclear reactor facility P3TM BATAN in three location. The twoimportant parameters used in this technique were growth time of Y-90 andstirring time. The result shown that activity of strontium-90 in the pos-01was between 1.801x10 -19 - 9.616x10 -17 μCi/cm 3 , pos-02 was8.448x10 -19 - 1.003x X 10 -16 μCi/cm 3 and pos-03 was 6.719x10 -19 - 11.644x10 -16 μCi/cm 3 . From those data shown that activity of Sr-90in the soil water of near nuclear reactor facility P3TM BATAN was still belowthe limit value of maximum concentration permitted i.e. 4.0x10 -7 -3.5x10 -6 μCi/cm 3 . The statistic test using analysis of varian twofactorial with random block design shown that the activity of Sr-90 in thesoil water was influenced by the interaction which take place between growthlong time of Y-90 and stirring long time. (author)

15. [Western blot technique standardization for specific diagnosis of Chagas disease using excretory-secretory antigens of Trypanosoma cruzi epimastigotes].

Science.gov (United States)

Escalante, Hermes; Jara, César; Davelois, Kelly; Iglesias, Miguel; Benites, Adderly; Espinoza, Renzo

2014-01-01

Evaluate the effectiveness of Western Blot for the specific diagnosis of Chagas disease using excretory-secretory antigens of Trypanosoma cruzi epimastigotes. Antigens were obtained after twenty hours of incubation in Eagles Minimum Essential Medium, which were prepared at a protein concentration of 0.2 ug/uL to be faced with 10 mL pool of serum from patients with Chagas disease and a conjugated anti-IgG labeled with peroxidase. The presence of the following antigens was observed: 10, 12, 14, 15, 19, 20, 23, 26, 30, 33, 36, 40, 42, 46, 58, 63, 69, 91, 100, and 112 kDa; of which antigens of 10, 12, 14, 15, 19, 20, 23, and 26 kDa were considered to be specific using pools of serum from patients with other parasitosis and serum from people with no parasites. The sensitivity of the technique was assessed using individual serum from 65 patients with Chagas disease; and the specificity with serum from 40 patients with other parasitosis, and serums from five people who did not have parasites. The technique has a sensitivity of 95.4% in the detection of one to eight specific bands, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 93.7%. Western Blot technique with excretory-secretory antigens of T. cruzi epimastigotes is effective in the diagnosis of Chagas disease in Peru; therefore, it can be used as a confirmatory test.

16. Chromatographic quality control procedures for /sup 99m/Tc-diagnostic agents

International Nuclear Information System (INIS)

Marinelli, M.; Pozzato, R.; Garuti, P.; Zucchini, G.L.

1986-01-01

The purpose of this work was to experiment simple and rapid chromatographic systems, based on paper and thin-layer techniques, to test the radiochemical purity of some common /sup 99m/Tc diagnostic agents, and select those systems able to prevent the anomalies due to oxidation and artifact production. The agents were examined under conditions which usually bring about the above mentioned anomalies, then the results were compared with those obtained under controlled conditions. Quali- and quantitative detection of the activity present on the chromatograms was carried out using the equipment available in nuclear medicine departments

17. Chromatographic separations on pyridinium tungstoarsenate-impregnated ion-exchange papers

International Nuclear Information System (INIS)

Ion-exchange papers were prepared by impregnating chromatographic Whatman No.3 paper with pyridinium tungstoarsenate exchanger. The composition of the material loaded on the paper shows that the compound has the formula (C 5 H 5 NH) 3 W 12 AsO 40 . Rsub(f) values of 30 metal ions were determined on these ion-exchange papers by developing with ascending technique in solvents containing mixtures of n-propanol and hydrochloric or nitric acid. Several binary, ternary and some quaternary separations were also achieved on these papers. Studies were also made on plain papers for comparison. (author)

18. Revising Reverse-Phase Chromatographic Behavior for Efficient Differentiation of Both Positional and Geometrical Isomers of Dicaffeoylquinic Acids

Directory of Open Access Journals (Sweden)

Keabetswe Masike

2018-01-01

Full Text Available Dicaffeoylquinic acids (diCQAs are plant metabolites and undergo trans-cis-isomerization when exposed to UV irradiation. As such, diCQAs exist in both trans- and cis-configurations and amplify the already complex plant metabolome. However, analytical differentiation of these geometrical isomers using mass spectrometry (MS approaches has proven to be extremely challenging. Exploring the chromatographic space to develop possible conditions that would aid in differentially separating and determining the elution order of these isomers is therefore imperative. In this study, simple chromatographic parameters, such as column chemistry (phenyl versus alkyl, mobile phase composition (methanol or acetonitrile, and column temperature, were investigated to aid in the separation of diCQA geometrical isomers. The high-performance liquid chromatography photodiode array (HPLC-PDA chromatograms revealed four isomers post UV irradiation of diCQA authentic standards. The elution profile/order was seen to vary on different reverse-phase column chemistries (phenyl versus alkyl using different mobile phase composition. Here, the elution profile/order on the phenyl-derived column matrices (with methanol as the mobile phase composition was observed to be relatively reproducible as compared to the alkyl (C18 columns. Chromatographic resolution of diCQA geometrical isomers can be enhanced with an increase in column temperature. Lastly, the study highlights that chromatographic elution order/profile cannot be relied upon to fathom the complexity of isomeric plant metabolites.

19. Green chromatographic fingerprinting: an environmentally friendly approach for the development of separation methods for fingerprinting complex matrices.

Science.gov (United States)

Funari, Cristiano Soleo; Carneiro, Renato Lajarim; Andrade, André Marques; Hilder, Emily Frances; Cavalheiro, Alberto José

2014-01-01

A chromatographic fingerprint is a comprehensive method that reveals the distinctive pattern of peaks across the chromatogram for a given sample. It is considered an effective strategy to assess the identity and quality of herbal materials, as well as for the control of the quality of their derived products. HPLC is the most employed technique for these purposes and it is used routinely for quality control in industry. Hence, its impact on the environment should not be neglected. This work provides a rational and generic procedure to qualitatively fingerprint complex matrices. Resource- and time-saving experimental designs were selected; an alternative safer organic solvent was tested and a time-saving and innovative response entitled the green chromatographic fingerprinting response was developed and employed. This procedure was applied in the development of chromatographic fingerprints for extracts of Bauhinia forficata and Casearia sylvestris. Moreover, the response proposed here can be combined with a complementary metric available in the literature to compare methods using different solvents. According to this, the chromatographic fingerprints developed here using ethanol as the organic solvent provided a performance better than that of reference methods in which more harmful acetonitrile or methanol were employed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

20. The co-feature ratio, a novel method for the measurement of chromatographic and signal selectivity in LC-MS-based metabolomics

Energy Technology Data Exchange (ETDEWEB)

Elmsjö, Albert, E-mail: Albert.Elmsjo@farmkemi.uu.se [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Haglöf, Jakob; Engskog, Mikael K.R. [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Nestor, Marika [Department of Immunology, Genetics and Pathology, Uppsala University (Sweden); Arvidsson, Torbjörn [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden); Medical Product Agency, Uppsala (Sweden); Pettersson, Curt [Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Uppsala University (Sweden)

2017-03-01

Evaluation of analytical procedures, especially in regards to measuring chromatographic and signal selectivity, is highly challenging in untargeted metabolomics. The aim of this study was to suggest a new straightforward approach for a systematic examination of chromatographic and signal selectivity in LC-MS-based metabolomics. By calculating the ratio between each feature and its co-eluting features (the co-features), a measurement of the chromatographic selectivity (i.e. extent of co-elution) as well as the signal selectivity (e.g. amount of adduct formation) of each feature could be acquired, the co-feature ratio. This approach was used to examine possible differences in chromatographic and signal selectivity present in samples exposed to three different sample preparation procedures. The capability of the co-feature ratio was evaluated both in a classical targeted setting using isotope labelled standards as well as without standards in an untargeted setting. For the targeted analysis, several metabolites showed a skewed quantitative signal due to poor chromatographic selectivity and/or poor signal selectivity. Moreover, evaluation of the untargeted approach through multivariate analysis of the co-feature ratios demonstrated the possibility to screen for metabolites displaying poor chromatographic and/or signal selectivity characteristics. We conclude that the co-feature ratio can be a useful tool in the development and evaluation of analytical procedures in LC-MS-based metabolomics investigations. Increased selectivity through proper choice of analytical procedures may decrease the false positive and false negative discovery rate and thereby increase the validity of any metabolomic investigation. - Highlights: • The co-feature ratio (CFR) is introduced. • CFR measures chromatographic and signal selectivity of a feature. • CFR can be used for evaluating experimental procedures in metabolomics. • CFR can aid in locating features with poor selectivity.

1. Physicochemical and chromatographic method of characterization of Matricaria recutita tinctures

Directory of Open Access Journals (Sweden)

Jonathan Parra

2016-02-01

Full Text Available Context: The pharmacological activity of medicinal products containing plant materials depends on their specific components. However, these components are not characterized in their entirety in all cases. Therefore, manufacturing processes must be duly characterized and validated. Aims: To characterize a chamomile (Matricaria recutita tincture through chemometric analysis of chromatographic data in order to establish quality parameters for its production. Methods: Various chamomile tinctures were manufactured and the precision and robustness of the production process for each was verified. The physicochemical properties of the tinctures were characterized and their chromatographic digital fingerprints analysed through chemometric methods. Results: A good correlation between the physicochemical characterization and the chromatographic analysis was demonstrated. The preparation methodology was proved to be repeatable as long as the source of the plant material is not altered. Conclusions: The principal component multivariate analysis of chromatograms was a helpful and simple tool for the characterization and traceability of the production method.

2. Miniaturized chromatographic radiochemical procedure for 131I - MIBG

International Nuclear Information System (INIS)

Barboza, M.F. de; Pereira, N.S. de; Colturato, M.T.; Silva, C.P.G. da.

1989-12-01

Different solvents were used in paper chromatographic methods to obtain the best system in routine radiochemical control for 131 I-MIBG produced at IPEN-CNEN/SP. The dates were compared with those obtained with eletrophoresis method in buffer acetate, pH=4.5, 350V, during 40 minutes. The stability of the labeled compound store under 4 0 C was studied during 15 days. Miniaturized chromatographic procedures were established using Whatman 3MM (8x1cm) and n-butanol-:acetic acid: water (S:2:1) as a solvent. the Rf values were: 0.3 (I - ) and 1.0 (MIBG). The radiochemical purity was 99.3 and 99.2% (first day) obtained with eletrophoresis and miniaturized chromatographic procedures, respectively and, 84.7% after 15 days of its preparation. It is a rapid, practical and reproductive method. (author) [pt

3. Coracoid bone graft osteolysis after Latarjet procedure: A comparison study between two screws standard technique vs mini-plate fixation

Science.gov (United States)

Giacomo, Giovanni Di; Costantini, Alberto; de Gasperis, Nicola; De Vita, Andrea; Lin, Bernard K. H.; Francone, Marco; Beccaglia, Mario A. Rojas; Mastantuono, Marco

2013-01-01

Aims: One of the reason for Latarjet procedure failure may be coracoid graft osteolysis. In this study, we aimed to understand if a better compression between the coracoid process and the glenoid, using a mini-plate fixation during the Latarjet procedure, could reduce the amount of coracoid graft osteolysis. Materials and Methods: A computed tomography scan analysis of 26 prospectively followed-up patients was conducted after modified Latarjet procedure using mini-plate fixation technique to determine both the location and the amount of coracoid graft osteolysis in them. We then compared our current results with results from that of our previous study without using mini-plate fixation to determine if there is any statistical significant difference in terms of corcacoid bone graft osteolysis between the two surgical techniques. Results: The most relevant osteolysis was represented by the superficial part of the proximal coracoid, whereas the deep part of the proximal coracoid graft is least involved in osteolysis and has best bone healing. The current study showed a significant difference only for the deep part of the distal coracoid with our previous study (P Latarjet procedure. Conclusion: Our study suggests that there is a significant difference only for the deep part of the distal coracoid in terms of osteolysis. At clinical examination, this difference did not correspond with any clinical findings. Level of Evidence: Level 4. Clinical Relevance: Prospective case series, Treatment study. PMID:23858288

4. Standardizing operational vector sampling techniques for measuring malaria transmission intensity: evaluation of six mosquito collection methods in western Kenya.

Science.gov (United States)

Wong, Jacklyn; Bayoh, Nabie; Olang, George; Killeen, Gerry F; Hamel, Mary J; Vulule, John M; Gimnig, John E

2013-04-30

Operational vector sampling methods lack standardization, making quantitative comparisons of malaria transmission across different settings difficult. Human landing catch (HLC) is considered the research gold standard for measuring human-mosquito contact, but is unsuitable for large-scale sampling. This study assessed mosquito catch rates of CDC light trap (CDC-LT), Ifakara tent trap (ITT), window exit trap (WET), pot resting trap (PRT), and box resting trap (BRT) relative to HLC in western Kenya to 1) identify appropriate methods for operational sampling in this region, and 2) contribute to a larger, overarching project comparing standardized evaluations of vector trapping methods across multiple countries. Mosquitoes were collected from June to July 2009 in four districts: Rarieda, Kisumu West, Nyando, and Rachuonyo. In each district, all trapping methods were rotated 10 times through three houses in a 3 × 3 Latin Square design. Anophelines were identified by morphology and females classified as fed or non-fed. Anopheles gambiae s.l. were further identified as Anopheles gambiae s.s. or Anopheles arabiensis by PCR. Relative catch rates were estimated by negative binomial regression. When data were pooled across all four districts, catch rates (relative to HLC indoor) for An. gambiae s.l (95.6% An. arabiensis, 4.4% An. gambiae s.s) were high for HLC outdoor (RR = 1.01), CDC-LT (RR = 1.18), and ITT (RR = 1.39); moderate for WET (RR = 0.52) and PRT outdoor (RR = 0.32); and low for all remaining types of resting traps (PRT indoor, BRT indoor, and BRT outdoor; RR < 0.08 for all). For Anopheles funestus, relative catch rates were high for ITT (RR = 1.21); moderate for HLC outdoor (RR = 0.47), CDC-LT (RR = 0.69), and WET (RR = 0.49); and low for all resting traps (RR < 0.02 for all). At finer geographic scales, however, efficacy of each trap type varied from district to district. ITT, CDC-LT, and WET appear to be effective methods for large-scale vector sampling in

5. Determination of Pu-238 Abundance in a Plutonium Standard by an Advanced Thermal Ionization Mass Spectrometric Technique

Science.gov (United States)

Mason, P.; Thomas, R.

2006-12-01

New developments in thermal ionization mass spectrometers allow for the determination of very small minor isotope ratios. The new hardware and software capabilities require attention to detail and accounting for additional sources of measurement uncertainty. The Pu-238 isotopic composition in New Brunswick Laboratory plutonium metal standard CRM 126-A was determined by thermal ionization mass spectrometry using combined Faraday cup and ion counting detection. A dynamic acquisition scheme was employed which provided for near real-time mass fractionation correction and ion counter/Faraday detector inter-calibration. Steps taken to minimize or eliminate isobaric U-238 interferences will be described, and an evaluation detailing contributions to the uncertainty, including SEM non-linearity, will be presented.

6. A semi-automated technique determining the liver standardized uptake value reference for tumor delineation in FDG PET-CT.

Directory of Open Access Journals (Sweden)

Kenji Hirata

Full Text Available 18F-fluorodeoxyglucose (FDG positron emission tomography (PET-computed tomography (CT has been an essential modality in oncology. We propose a semi-automated algorithm to objectively determine liver standardized uptake value (SUV, which is used as a threshold for tumor delineation.A large spherical volume of interest (VOI was placed manually to roughly enclose the right lobe (RL of the liver. For each voxel in this VOI, a coefficient of variation of voxel values (CVv was calculated for neighboring voxels within a radius of d/2. The voxel with the minimum CVv was then selected, where a 30-mm spherical VOI was placed at that voxel in accordance with PERCIST criteria. Two nuclear medicine physicians independently defined 30-mm VOIs manually on 124 studies in 62 patients to generate the standard values, against which the results from the new method were compared.The semi-automated method was successful in determining the liver SUV that was consistent between the two physicians in all the studies (d = 80 mm. The liver SUV threshold (mean +3 SD within 30-mm VOI determined by the new semi-automated method (3.12±0.61 was not statistically different from those determined by the manual method (Physician-1: 3.14±0.58, Physician-2: 3.15±0.58. The semi-automated method produced tumor volumes that were not statistically different from those by experts' manual operation. Furthermore, the volume change in the two sequential studies had no statistical difference between semi-automated and manual methods.Our semi-automated method could define the liver SUV robustly as the threshold value used for tumor volume measurements according to PERCIST. The method could avoid possible subjective bias of manual liver VOI placement and is thus expected to improve clinical performance of volume-based parameters for prediction of cancer treatment response.

7. Minimal immunoreactive plasma beta-endorphin and decrease of cortisol at standard analgesia or different acupuncture techniques.

Science.gov (United States)

Harbach, H; Moll, B; Boedeker, R-H; Vigelius-Rauch, U; Otto, H; Muehling, J; Hempelmann, G; Markart, P

2007-04-01

Acupuncture has been claimed to be associated with activation of the endogenous antinociceptive system. The analgesic effects of acupuncture have been ascribed to beta-endorphin interacting with opioid receptors. However, firstly, the release of beta-endorphin into the blood has been proven to be induced by stress, i.e. under dysphoric conditions, and, secondly, if released under stress, beta-endorphin has been shown not to be analgesic. Our aim was to test whether beta-endorphin immunoreactive material is released into the cardiovascular compartment during acupuncture comparing the most frequently used types of acupuncture with standard pain treatment under apparently low stress conditions. This prospective study included 15 male patients suffering from chronic low back pain. beta-Endorphin immunoreactive material and cortisol were measured in the plasma of patients who underwent, in random order, therapy according to a standard pain treatment, traditional Chinese acupuncture, sham acupuncture, electro acupuncture and electro acupuncture at non-acupuncture points before, at and after the treatment. Statistical analysis was performed using two-way ANOVA with repeated measures. A decrease in plasma cortisol concentration measured over the five treatment protocols was highly significant (P < 0.001). The beta-endorphin immunoreactive material concentrations in plasma were minimal at all times and in all treatment conditions. The influence of treatments by various acupuncture procedures on cortisol and beta-endorphin immunoreactive material plasma concentrations over the three time points was not significantly different. beta-endorphin immunoreactive material in blood is not released by any type of acupuncture as tested under low stress conditions.

8. Rapid high performance liquid chromatographic determination of ...

African Journals Online (AJOL)

SERVER

2007-06-18

Jun 18, 2007 ... Samples were extracted with dichloromethane and the organic layer evaporated to dryness. The residue was dissolved in methanol, and 25 µl aliquot injected onto the column. Tolbutamide was used as the internal standard for chlorpropamide. The UV detector response was linear over the range 0 – 300.

9. Rapid high performance liquid chromatographic determination of ...

African Journals Online (AJOL)

Samples were extracted with dichloromethane and the organic layer evaporated to dryness. The residue was dissolved in methanol, and 25 ìl aliquot injected onto the column. Tolbutamide was used as the internal standard for chlorpropamide. The UV detector response was linear over the range 0 – 300 ìg/ml, with a ...

10. Impact of Standardized Simulated Patients on First-Year Pharmacy Students' Knowledge Retention of Insulin Injection Technique and Counseling Skills.

Science.gov (United States)

Bowers, Riley; Tunney, Robert; Kelly, Kim; Mills, Beth; Trotta, Katie; Wheeless, C Neil; Drew, Richard

2017-08-01

Objective. To compare pre- and post-intervention test scores assessing insulin injection technique and counseling skills among P1 students with (intervention) or without (control) simulated patients, and to compare counseling checklist and knowledge retention test scores between groups. Methods. This study utilized cluster randomization. In addition to traditional instruction, the intervention group counseled a simulated patient on the use of insulin using the teach-back method. Test score changes from baseline were analyzed via two-sample t-test. Results. The intervention group exhibited a significantly greater increase in knowledge test scores from baseline compared to the control group. Similar changes were seen in post-instruction counseling checklist scores and knowledge retention test scores from baseline. Conclusion. Simulated patient interactions, when added to traditional coursework within a P1 skills lab, improve student counseling aptitude and knowledge retention scores.

11. Layout techniques to enhance the radiation tolerance of standard CMOS technologies demonstrated on a pixel detector readout chip

CERN Document Server

Snoeys, W; Burns, M; Campbell, M; Cantatore, E; Carrer, N; Casagrande, L; Cavagnoli, A; Dachs, C; Di Liberto, S; Formenti, F; Giraldo, A; Heijne, Erik H M; Jarron, Pierre; Letheren, M F; Marchioro, A; Martinengo, P; Meddi, F; Mikulec, B; Morando, M; Morel, M; Noah, E; Paccagnella, A; Ropotar, I; Saladino, S; Sansen, Willy; Santopietro, F; Scarlassara, F; Segato, G F; Signe, P M; Soramel, F; Vannucci, Luigi; Vleugels, K

2000-01-01

A new pixel readout prototype has been developed at CERN for high- energy physics applications. This full mixed mode circuit has been implemented in a commercial 0.5 mu m CMOS technology. Its radiation tolerance has been enhanced by designing all NMOS transistors in enclosed geometry and introducing guardrings wherever necessary. The technique is explained and its effectiveness demonstrated on various irradiation measurements on individual transistors and on the prototype. Circuit performance started to degrade only after a total dose of 600 krad-1.7 Mrad depending on the type of radiation. 10 keV X-rays, /sup 60/Co gamma-rays, 6.5 MeV protons, and minimum ionizing particles were used. Implications of this layout approach on the circuit design and perspectives for even deeper submicron technologies are discussed. (20 refs).

12. Use of the iTClamp versus standard suturing techniques for securing chest tubes: A randomized controlled cadaver study

Directory of Open Access Journals (Sweden)

Jessica Mckee

2018-03-01

Full Text Available Objectives: Tube thoracostomy (TT is a common yet potentially life-saving trauma procedure. After successful placement however, securing a TT through suturing is a skillset that requires practice, risking that the TT may become dislodged during prehospital transport. The purpose of this study was to examine if the iTClamp was a simpler technique with equivalent effectiveness for securing TTs. Materials and methods: In a cadaver model, a 1.5 inch incision was utilized along the upper border of the rib below the 5th intercostal space at the anterior axillary line. TTs (sizes 28Fr, 32Fr, 36Fr and 40Fr were inserted and secured with both suturing and iTClamp techniques according to the preset randomization. TT were then functionally tested for positive and negative pressure as well as the force required to remove the TT (pull test-up to 5 lbs. Time to secure the TT was also recorded. Results: When sutured is placed by a trained surgeon, the sutures and iTClamp were functionally equivalent for holding a positive and negative pressure. Mean pull force for both sutures and iTClamp exceeded the 5 lb threshold; there was no significant difference between the groups. Securing the TT with the iTClamp was significantly faster (p < 0.0001 with the iTClamp having a mean application time of 37.0 ± 22.8 s and using a suture had a man application time of 96.3 ± 29.0 s. Conclusion: The iTClamp was effective in securing TTs. The main benefit to the iTClamp is that minimal skill is required to adequately secure a TT to ensure that it does not become dislodged during transport to a trauma center. Keywords: Chest tube, Tube thoracostomy, Securing chest tubes

13. Ion chromatographic determination of sulfites in foods.

Science.gov (United States)

Anderson, C; Warner, C R; Daniels, D H; Padgett, K L

1986-01-01

Ion chromatography (IC) is shown to be a promising technique for the determination of sulfites (SO2, SO2/3-) in foods. Results of a 10 min flash distillation and 10 min IC determination compare favorably with the results from the conventional Monier-Williams method for total sulfite in a variety of food matrices. The IC technique also provides a wealth of additional information, such as (1) sulfite and sulfate (oxidized sulfite) content of the spiking or treatment solution, (2) residual sulfite applied to the food after oxidation losses in the treatment process, (3) free sulfite in foods, and (4) total sulfite in foods. As a further check on the Monier-Williams method, the sulfate content of the trapping solution can be determined by IC. Because the IC technique traps the liberated SO2 in a non-oxidizing rather than an oxidizing medium, it is considered free from interfering sulfides and organic sulfur-containing groups which can give false positives in the Monier-Williams method. IC thus offers a high speed, more sensitive, and cost-effective alternative to conventional techniques for the determination of sulfite in foods.

14. Development, standardization and validation of purine excretion technique for measuring microbial protein supply for Yerli Kara cross-breed cattle

International Nuclear Information System (INIS)

Cetinkaya, N.; Ozdemir, H.; Gucus, A.I.; Ozcan, H.; Sogut, A.; Yaman, S.

2002-01-01

Three experiments were conducted to evaluate of the developed techniques for uric acid, allantoin and creatinine in Yerli Kara cross-breed cattle on farm at different feeding level locally available feed resources and linking the observed information to feed intake and to assess of protein nutrition status of Yerli Kara cross-breed dairy cattle using urinary PD and creatinine excretion. In Experiment I. Response of daily PD excretion to feed intake in Yerli Kara cross-breed on state farm was measured. Animals were fed a mixed diet containing 30 % wheat straw and 70 % compounded feed. The diet contained 90 % DM, its N and OM contents were 124 and 950 g/kg DM, respectively. In Experiment II. Spot urine sampling techniques was applied at state farm. Four Yerli Kara cross-breed bulls live weight with a mean of 211±41.3 kg were used. Experimental design, feeding and diet were the same as in Experiment I. The treatments were [located according to a 4x4 Latin Square design. In Experiment III. Spot urine sampling techniques was applied at smallholder farms. Compound feed containing 65 % barley, 25 % bran, 6 % sunflower seed meal, 3 % manner dust and 1 % mineral and vitamin mixture (120 g/kg DM-Crude Protein and 950 g/kg DM-Organic Matter)- was offered total in between 2 to 3 kg in two parts one in the morning (07:30 h) and one in the afternoon (17:00 h). Compound feed ingredients were similar given to all animals but Groups I, II and III animals were receiving 1 to 2 kg/d of straw (30 g CP/kg DM, 93Og OM/kg DM), grass hay (70g CP/kg DM, 915 g OM/kg DM), straw and grass hay respectively. There were significant correlations (R 2 =0.99) between PD excretion (mmol/d) and DOMI (kg/d) for YK-C cattle. PD execration (mmol/L) was plotted against PD: Creatinine W 0.75 to obtain slope and use as constant for the estimation of daily PD excretion from spot sampling from animals held by small holders. The equation could be expressed as: PD (mmol/d)=8.27+0.960 (PD:CxW 0.75 ). The

15. Internal standardization--atomic spectrometry and geographical pattern recognition techniques for the multielement analysis and classification of Catalonian red wines.

Science.gov (United States)

Iglesias, Mònica; Besalú, Emili; Anticó, Enriqueta

2007-01-24

Major and minor (K, P, Ca, Mg, Na, Fe, Mn, Zn, and Sr) and trace (Ba, Ni, Pb, V, Co, Cd, and Sb) elements from wine samples from the Denomination of Origin (DO) Empordà-Costa Brava (Catalonia, Spain) were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) respectively. Previously, a comparison of different calibration methodologies and sample digestion treatments had been carried out using ANOVA statistical tool. The obtained results demonstrated that internal standardization provides reliable results with the advantage that no further manipulation of the sample is needed. A principal component analysis of the concentration data was performed to differentiate the samples of DO Empordà-Costa Brava from wine samples from other wine-producing regions in Spain (i.e., Penedès, Somontano, and Rioja). It was found that Sr and Ba contents discriminate the two DO groups. Moreover, a discriminant analysis function involving both variables distinguishes the two groups with a 100% classification rate. At the level of the leave-one-out cross-validation, all of the Empordà-Costa Brava samples were well classified, whereas the other DOs presented two borderline misclassifications.

16. Standard Test Method for Measurement of Hydrogen Embrittlement Threshold in Steel by the Incremental Step Loading Technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2009-01-01

1.1 This test method establishes a procedure to measure the susceptibility of steel to a time-delayed failure such as that caused by hydrogen. It does so by measuring the threshold for the onset of subcritical crack growth using standard fracture mechanics specimens, irregular-shaped specimens such as notched round bars, or actual product such as fasteners (2) (threaded or unthreaded) springs or components as identified in SAE J78, J81, and J1237. 1.2 This test method is used to evaluate quantitatively: 1.2.1 The relative susceptibility of steels of different composition or a steel with different heat treatments; 1.2.2 The effect of residual hydrogen in the steel as a result of processing, such as melting, thermal mechanical working, surface treatments, coatings, and electroplating; 1.2.3 The effect of hydrogen introduced into the steel caused by external environmental sources of hydrogen, such as fluids and cleaners maintenance chemicals, petrochemical products, and galvanic coupling in an aqueous enviro...

17. Detection of active noise control on the standard motorcycle exhaust Supra X 125 D using PVC pipe technique form Y

Science.gov (United States)

Isranuri, I.; Alfisyahrin; Nasution, A. R.

2018-02-01

This detection aims to obtain noise reduction on the supra X 125D motorcycle exhaust by using the Active Noise Control Method. The technique is done using a Y-shaped PVC pipe to be bolted on the exhaust, which then branch Y PVC is placed loudspeaker with impermeable conditions. The function of this loudspeaker is as a secondary noise to counter the primary noise of the sound of exhaust motorcycle Supra X 125D. The sound generator in this study is the ISD 4004 module, which serves to generate noise to counter the source noise. How this ISD 4004 module works is by recording source noise then recording the source noise and then reversed the phase 180° by phase reversing circuit. So that, the noise generated by the sound generator will hit the source noise and encounter or such as addition of two different phase of sound will result in noise reduction when detected at the end of the Y-shaped PVC pipe. Inverted phase reversed using feed-back resistor 1 kΩ and 2 kΩ input resistors, 16V capacitor 2500μf and as amplifier using ICL 7660 and TL 702 CP. Test results on the highest 1000 rpm rotation engine speed on the Z axis of 2 dB, and at the highest 2000 rpm rotation engine speed also occurs on the Z axis of 1.5 dB.

18. Evaluation of Image Processing Technique for Measuring of Nitrogen and Yield in Paddy Rice and Comparing it with Standard Methods

Directory of Open Access Journals (Sweden)

M.R Larijani

2011-09-01

Full Text Available In order to use new and low cost methods in precision agriculture, nitrogen should be supplied for plants on time and precisely. For determining the required nitrogen of paddy rice in the clustering stage, a series of experiments were conducted using three different methods of: image processing, kjeldahl and chlorophyll meter set (SPAD-502, in a randomized complete block design with three replications during 2010 at Rice Research Center of Tonekabon, Iran. Four experimental treatments were different level of fertilizer (Urea with 46% nitrogen. In the clustering stage, some images from rice plants were taken vertically by a digital camera and were analyzed using image processing technique. Simultaneously the chlorophyll index of plants was measured by SPAD-502 chlorophyll meter set and the percentage amount of nitrogen was measured using of the so called kjeldahl laboratory method. The results showed that the three methods of determining nitrogen of rice plant were highly correlated. Moreover, the correlation among the three methods and crop yield were almost the same. In general, the method of image processing could have a high potential for nitrogen management in the field, while this method was low-cost, faster and also nondestructive in comparison to the other methods.

19. Scaffolds with a standardized macro-architecture fabricated from several calcium phosphate ceramics using an indirect rapid prototyping technique

Science.gov (United States)

Wilson, C. E.; van Blitterswijk, C. A.; Verbout, A. J.; de Bruijn, J. D.

2010-01-01

Calcium phosphate ceramics, commonly applied as bone graft substitutes, are a natural choice of scaffolding material for bone tissue engineering. Evidence shows that the chemical composition, macroporosity and microporosity of these ceramics influences their behavior as bone graft substitutes and bone tissue engineering scaffolds but little has been done to optimize these parameters. One method of optimization is to place focus on a particular parameter by normalizing the influence, as much as possible, of confounding parameters. This is difficult to accomplish with traditional fabrication techniques. In this study we describe a design based rapid prototyping method of manufacturing scaffolds with virtually identical macroporous architectures from different calcium phosphate ceramic compositions. Beta-tricalcium phosphate, hydroxyapatite (at two sintering temperatures) and biphasic calcium phosphate scaffolds were manufactured. The macro- and micro-architectures of the scaffolds were characterized as well as the influence of the manufacturing method on the chemistries of the calcium phosphate compositions. The structural characteristics of the resulting scaffolds were remarkably similar. The manufacturing process had little influence on the composition of the materials except for the consistent but small addition of, or increase in, a beta-tricalcium phosphate phase. Among other applications, scaffolds produced by the method described provide a means of examining the influence of different calcium phosphate compositions while confidently excluding the influence of the macroporous structure of the scaffolds. PMID:21069558

20. [Western blot technique standardization of the diagnosis of human fasciolosis using Fasciola hepatica excreted-secreted antigens].

Science.gov (United States)

Escalante, Hermes; Davelois, Kelly; Ortiz, Pedro; Rodríguez, Hans; Díaz, Enrique; Jara, César

2011-01-01

To evaluate the performance of the enzyme-linked immunoelectrotransfer blot assay (EITB, Western blot) using excretory/secretory antigens from adult forms of Fasciola hepatica (Fh E/S Ag) for the diagnosis of human fasciolosis. Antigens were obtained after 18 hours of incubation in culture medium Minimum Essential Eagle, prepared at a protein concentration of 0.15 ug/uL and run against a pool of sera of patients with proven fasciolosis (confirmed by the finding of parasite eggs in the stool microscopy). Antigens of 10, 12, 17, 23, 27, 30, 36, 43, 66 and 136 kDa were detected and used to develop the Western blot technique. The sensitivity was evaluated using sera from 67 fasciolosis patients, and the specificity using sera from 57 patients with other parasitic diseases, and 10 from healthy individuals. Out of the 67 sera, 64 reacted with the 23 kDa band and 61 with the one of 17 kDa. These two bands were not detected in sera from patients with other parasitic diseases or in those from healthy volunteers and thus could be considered specific and diagnostic. The sensitivity of the test, using the bands of 17 and 23 kDa, was 95.5% for positive reactions to at least one of these two bands, being its specificity 100% with a positive predictive value of 100% and negative predictive value of 95.71%.

1. Actual survey of dose evaluation method for standardization of radiation therapy techniques. With special reference to display method of radiation doses

International Nuclear Information System (INIS)

Kumagai, Kozo; Yoshiura, Takao; Izumi, Takashi; Araki, Fujio; Takada, Takuo; Jingu, Kenichi.

1994-01-01

This report presents the results of questionnaire survey for actual conditions of radiation therapy, which was conducted with the aim of establishing the standardization of radiation therapy techniques. Questionnaires were sent to 100 facilities in Japan, and 86 of these answered, consisting of 62 university hospitals, 2 national hospitals, 14 cancer centers, 4 prefectural or municipal hospitals, and 4 other hospitals. In addition to electron beam therapy, the following typical diseases for radiation therapy were selected as standard irradiation models: cancers of the larynx, esophagus, breast, and uterine cervix, and malignant lymphomas. According to these models, questionnaire results are analyzed in terms of the following four items: (1) irradiation procedures, (2) energy used for radiotherapy, (3) the depth for calculating target absorption doses, and (4) points for displaying target absorption doses. (N.K.)

2. Salivary Fluoride level in preschool children after toothbrushing with standard and low fluoride content dentifrice, using the transversal dentifrice application technique: pilot study

Directory of Open Access Journals (Sweden)

Fabiana Jandre Melo

2008-01-01

Full Text Available Objective: To investigate the salivary fluoride concentration in pre-school children after toothbrushing with dentifrice containing standard (1100ppmF/NaF and low (500ppmF/NaF fluoride concentration, using the transversal technique of placing the product on the toothbrush. Methods: Eight children of both sexes, ranging from 4 to 9 years, and 5 years and 6 months of age, participated in the study. The experiment was divided into two phases with a weekly interval. In the first stage, the children used the standard concentration dentifrice for one week, and in the second, the low concentration product. Samples were collected at the end of each experimental stage, at the following times: Before brushing, immediately afterwards, and after 15, 30 and 45 minutes. The fluoride contents were analyzed by the microdiffusion technique. Statistical analysis was done by the analysis of variance ANOVA and Student’s-t test (p<0.05. Results: The salivary fluoride concentration was significantly higher at all times, when the standard concentration product was used. The comparison between the Halogen concentration found before bushing and immediately afterwards, showed that there was a 6.8 times increase in the standard dentifrice (0.19 x 1.29μgF/ml and in the low concentration product, an increase of 20.5 times (0.02 x 0.41μgF/ml. Conclusion: Toothbrushing with both products promoted relevant increases in the salivary fluoride concentration; however, longitudinal studies are necessary to verify the clinical result of this measurement.

3. Precision of a photogrammetric method to perform 3D wound measurements compared to standard 2D photographic techniques in the horse.

Science.gov (United States)

Labens, R; Blikslager, A

2013-01-01

Methods of 3D wound imaging in man play an important role in monitoring of healing and determination of the prognosis. Standard photographic assessments in equine wound management consist of 2D analyses, which provide little quantitative information on the wound bed. 3D imaging of equine wounds is feasible using principles of stereophotogrammetry. 3D measurements differ significantly and are more precise than results with standard 2D assessments. Repeated specialised photographic imaging of 4 clinical wounds left to heal by second intention was performed. The intraoperator variability in measurements due to imaging and 3D processing was compared to that of a standard 2D technique using descriptive statistics and multivariate repeated measures ANOVA. Using a custom made imaging system, 3D analyses were successfully performed. Area and circumference measurements were significantly different between imaging modalities. The intraoperator variability of 3D measurements was up to 2.8 times less than that of 2D results. On average, the maximum discrepancy between repeated measurements was 5.8% of the mean for 3D and 17.3% of the mean for 2D assessments. The intraoperator repeatability of 3D wound measurements based on principles of stereophotogrammetry is significantly increased compared to that of a standard 2D photographic technique indicating it may be a useful diagnostic and monitoring tool. The equine granulation bed plays an important role in equine wound healing. When compared to 2D analyses 3D monitoring of the equine wound bed allows superior quantitative characterisation, contributing to clinical and experimental investigations by offering potential new parameters. © 2012 EVJ Ltd.

4. Generation of gaseous methanol reference standards

International Nuclear Information System (INIS)

Geib, R.C.

1991-01-01

Methanol has been proposed as an automotive fuel component. Reliable, accurate methanol standards are essential to support widespread monitoring programs. The monitoring programs may include quantification of methanol from tailpipe emissions, evaporative emissions, plus ambient air methanol measurements. This paper will present approaches and results in the author's investigation to develop high accuracy methanol standards. The variables upon which the authors will report results are as follows: (1) stability of methanol gas standards, the studies will focus on preparation requirements and stability results from 10 to 1,000 ppmv; (2) cylinder to instrument delivery system components and purge technique, these studies have dealt with materials in contact with the sample stream plus static versus flow injection; (3) optimization of gas chromatographic analytical system will be discussed; (4) gas chromatography and process analyzer results and utility for methanol analysis will be presented; (5) the accuracy of the methanol standards will be qualified using data from multiple studies including: (a) gravimetric preparation; (b) linearity studies; (c) independent standards sources such as low pressure containers and diffusion tubes. The accuracy will be provided as a propagation of error from multiple sources. The methanol target concentrations will be 10 to 500 ppmv

5. Characterization of crude oils and petroleum products: (I Elution liquid chromatographic separation and gas chromatographic analysis of crude oils and petroleum products

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E.O. Odebunmi

2002-12-01

Full Text Available Some physical and chemical properties of samples of light, medium and heavy Nigerian crude oils and petroleum products including gasoline, kerosene and engine oil have been measured and are reported in this paper. The crude oils and petroleum products have also been characterized by fractional distillation and elution liquid chromatography. The fractions obtained from elution liquid chromatography were analyzed using gas chromatography (GC. The GC fractions were identified by comparing the retention time of peaks in the unknown samples with those of components of calibration standard mixtures. The importance of the physico-chemical properties and the significance of the fractional distillation and chromatographic separation methods to industrial process operations have been discussed.

6. Liquid Chromatographic Determination of Alternaria Toxins in Carrots

NARCIS (Netherlands)

Solfrizzo, M.; Girolamo, De A.; Vitti, C.; Bulk, van den R.W.

2004-01-01

A liquid chromatographic (LC) method was developed for the determination of Alternaria radicina and A. alternata toxins in carrots. Toxins were extracted from carrot with an acidified mixture of water¿methanol¿acetonitrile. The filtered extract was divided in 2 parts that were purified by

7. Sensitive high performance liquid chromatographic method for the ...

African Journals Online (AJOL)

A new simple, sensitive, cost-effective and reproducible high performance liquid chromatographic (HPLC) method for the determination of proguanil (PG) and its metabolites, cycloguanil (CG) and 4-chlorophenylbiguanide (4-CPB) in urine and plasma is described. The extraction procedure is a simple three-step process ...

8. Development and Validation of a Liquid Chromatographic Method ...

African Journals Online (AJOL)

A liquid chromatographic method for the simultaneous determination of six human immunodeficiency virus (HIV) protease inhibitors, indinavir, saquinavir, ritonavir, amprenavir, nelfinavir and lopinavir, was developed and validated. Optimal separation was achieved on a PLRP-S 100 Å, 250 x 4.6 mm I.D. column maintained ...

9. Transport Characteristics of Porous Solids Derived from Chromatographic Measurements

Czech Academy of Sciences Publication Activity Database

Šolcová, Olga; Schneider, Petr

2002-01-01

Roč. 144, - (2002), s. 475-482 ISSN 0167-2991 R&D Projects: GA ČR GA104/01/0546; GA AV ČR IAA4072915 Keywords : transport parameters * diffusion coefficients * chromatographic column Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.468, year: 2002

10. Optimizing Chromatographic Separation: An Experiment Using an HPLC Simulator

Science.gov (United States)

Shalliker, R. A.; Kayillo, S.; Dennis, G. R.

2008-01-01

Optimization of a chromatographic separation within the time constraints of a laboratory session is practically impossible. However, by employing a HPLC simulator, experiments can be designed that allow students to develop an appreciation of the complexities involved in optimization procedures. In the present exercise, a HPLC simulator from "JCE…

11. Evaluation of a gas chromatograph with a novel surface acoustic wave detector (SAW GC) for screening of volatile organic compounds in Hanford waste tank samples

International Nuclear Information System (INIS)

Lockrem, L.L.

1998-01-01

A novel instrument, a gas chromatograph with a Surface Acoustic Wave Detector (SAW GC), was evaluated for the screening of organic compounds in Hanford tank headspace vapors. Calibration data were developed for the most common organic compounds, and the accuracy and precision were measured with a certified standard. The instrument was tested with headspace samples collected from seven Hanford waste tanks

12. Gas chromatographic sensing on an optical fiber by mode-filtered light detection.

Science.gov (United States)

Bruckner, C A; Synovec, R E

1996-06-01

A chemical sensor for gas phase measurements is reported which combines the principles of chemical separation and fiber optic detection. The analyzer incorporates an annular column Chromatographic sensor, constructed by inserting a polymer-clad optical fiber into a silica capillary. Light from a helium-neon laser is launched down the fiber, producing a steady intensity distribution within the fiber, but a low background of scattered light. When sample vapor is introduced to the sensor, and an analyte-rich volume interacts with the polymer cladding, Chromatographic retention is observed simultaneously with a change in the local refractive index of the cladding. An increase in cladding refractive index (RI) causes light to be coupled out of the fiber, with detection at a right-angle to the annular column length to provide optimum S/N ratio. This detection mechanism is called mode-filtered light detection. We report a gas Chromatographic separation on a 3.1 m annular column (320 microm i.d. silica tube, 228 microm o.d. fiber with a 12 microm fluorinated silicone clad) of methane, benzene, butanone and chlorobenzene in 6 min. The annular column length was reduced to 22 cm to function as a sensor, with selected organic vapors exhibiting unique retention times and detection selectivity. The detection selectivity is determined by the analyte RI and the partition coefficient into the cladding. The calculated limit of detection (LOD) for benzene vapor is 0.03% by volume in nitrogen, and several chlorinated species had LOD values less than 1%. For binary mixtures of organic vapors, the detected response appears to be the linear combination of the two organic standards, suggesting that the annular column may be useful as a general approach for designing chemical sensors that incorporate separation and optical detection principles simultaneously.

13. Reversed-phase ion-pair chromatographic analysis of tetracycline antibiotics. Application to discolored teeth.

Science.gov (United States)

Tanase, S; Tsuchiya, H; Yao, J; Ohmoto, S; Takagi, N; Yoshida, S

1998-03-20

A high-performance liquid chromatographic method with diode array detection was developed to simultaneously separate tetracycline antibiotics and applied to the analysis of discolored teeth. By a reversed-phase ion-pair chromatographic system using pentanesulfonate as a counter ion, minocycline, oxytetracycline, tetracycline and demeclocycline were eluted in this order, and they showed base-line separation within 9 min. When using oxytetracycline as an internal standard, the quantitative ranges were between 2.5 ng/ml and 7.5 microg/ml. Powdered dentine (10 mg) and enamel (40 mg) prepared from discolored primary teeth were sonicated in 0.25 ml of 10 mM HCl containing oxytetracycline (0.75 microg/ml) and 50 mM EDTA-2Na, thereafter the supernatants were chromatographed. Eluates from both discolored tooth samples were identified as minocycline based on diode array spectra of their peaks, while minocycline was not detected in any samples from nondiscolored normal teeth, indicating that discoloration of the tested teeth was due to minocycline incorporated into dentine and enamel. Replicate quantitative analyses of the identical tooth substances showed that intra- and inter-assay C.V.s were 2.63 and 4.95% for dentine, and 5.42 and 10.88% for enamel. Application of the developed method to nine discolored teeth revealed that the incorporated minocycline ranged from 20.13 to 84.62 ng/mg of dentine and 0.89 to 7.87 ng/mg of enamel.

14. Standardization of radiochemical techniques aiming the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region

International Nuclear Information System (INIS)

Guimaraes, Jean Remy Davee

1992-09-01

Methylation of inorganic Hg in aquatic systems is a key process in the environmental cycling of this metal, not yet studied in tropical conditions. Radiochemical techniques were adapted and simplified, aiming at the study of Hg volatilization and methylation in water and sediment of gold mining areas in the Amazon region. Preliminary experiments showed, in 35 days volatilization of up to 32 % of 203 Hg 2+ added to aqueous solutions. Acid K 2 Cr 2 0 7 0.1 M solutions were not effective in 203 Hg 0 trapping and the latter was highly and irreversibly absorbed by a variety of synthetic materials commonly used in laboratory work. Considerably simplified versions of the Furutani and Rudd (1980) radiochemical technique for the determination of methylation rates in environmental samples were developed and showed efficiencies close to 90 % in tests with methyl- 2 0 3 H g standards. In-situ incubations of surface sediments were performed in the Madeira River gold mining region, Rondonia State, Brazil, and potential net Hg methylation rates (MR) of up to 1 %.g-1.h-1 were found in black-water affluent like the Mutum-Parana and Jamari rivers and in the Samuel reservoir. MRs in the Madeira River sediments were lower, ranging 10-5 to 10-3 %.g-1.h-1 . MRs obtained in incubations of samples some weeks after collection were one or two orders of magnitude lower than those resulting from in-situ incubations. Methylation in autoclaved samples was close to minimum detectable rates. MRs in surface water samples was in all cases < 7.10-7 %.ml-1.h-1. The determination of the predominant methylation sites will allow a better standardization of the technique described herein, suitable for MR determinations even under the unfavorable conditions prevailing in the Amazon region. (author)

15. Electrospray[+] tandem quadrupole mass spectrometry in the elucidation of ergot alkaloids chromatographed by HPLC: screening of grass or forage samples for novel toxic compounds.

Science.gov (United States)

Lehner, Andreas F; Craig, Morrie; Fannin, Neil; Bush, Lowell; Tobin, Tom

2005-11-01

Ergot alkaloids are mycotoxins generated by grass and grain pathogens such as Claviceps, for example. Ergot alkaloid-poisoning syndromes, such as tall fescue toxicosis from endophyte-infected tall fescue grass, are important veterinary problems for cattle, horses, sheep, pigs and chickens, with consequent impact on food, meat and dairy industries. Damage to livestock is of the order of a billion dollars a year in the United States alone. HPLC with UV and fluorescence detection are the predominant means of ergot alkaloid determination, with focus on quantitation of the marker compound ergovaline, although ELISA methods are undergoing investigation. These techniques are excellent for rapid detection, but of poor specificity in defining new or poorly characterized ergot alkaloids and related compounds. This paper demonstrates the facility of using electrospray(+) mass spectrometry with multiple reaction monitoring (MRM) detection during chromatographic examination of ergot alkaloid standards of lysergic acid, lysergol, ergonovine, ergovaline, ergotamine, ergocornine, ergocryptine and ergocrystine by HPLC. Ergoline-8 position epimers could be separated on the gradient HPLC system for ergocornine, ergocrystine and ergonovine and appeared as shoulders for ergotamine and ergovaline; epimers generally showed different patterns of relative intensity for specific MRM transitions. There was reasonable correspondence between retention of standards on the 2-mm ESI(+)MS phenyl-hexyl-based reverse phase column and those on the 4-mm C18-based column. Since up to 10% of clinical cases involving toxin exposure display unidentified chromatographic peaks, 11 samples of feed components associated with such cases were studied with developed MRM methods to attempt elucidation of crucial components if possible. Ergotamine appeared in all, ergovaline appeared in five and ergocornine appeared in six; ergonovine, ergocryptine, ergocrystine and lysergol also appeared in several. In addition

16. Free and total biotherapeutic evaluation in chromatographic assays: interference from targets and immunogenicity.

Science.gov (United States)

White, Joleen T; Bonilla, Leo E

2012-10-01

Measurement of drug concentrations is critical during drug development, supporting evaluation of safety and efficacy in the context of pharmacokinetics. Protein-based therapeutics have been historically measured by immunoassay methods. Technological advances provide new opportunities to measure these biotherapeutics using previously incompatible chromatographic techniques, such as MS. These advances are breaking down the barriers between 'large-molecule' and 'small-molecule' bioanalysis, and pushing scientists outside their comfort zones. One challenge in measuring biotherapeutic concentration is potential impact from other matrix components, such as therapeutic target or antidrug antibodies. Depending on the specific assay development objective, target interference could be either desired (favoring free measurement) or undesired (favoring total measurement). Orthogonal techniques provide additional tools to meet this challenge. The goal of this review is to introduce both small- and large-molecule bioanalytical scientists to the opportunities and challenges to consider while evaluating orthogonal methods for biotherapeutic bioanalysis.

17. Headspace solid-phase microextraction procedures for gas chromatographic analysis of biological fluids and materials.

Science.gov (United States)

Mills, G A; Walker, V

2000-12-01

Solid-phase microextraction (SPME) is a new solventless sample preparation technique that is finding wide usage. This review provides updated information on headspace SPME with gas chromatographic separation for the extraction and measurement of volatile and semivolatile analytes in biological fluids and materials. Firstly the background to the technique is given in terms of apparatus, fibres used, extraction conditions and derivatisation procedures. Then the different matrices, urine, blood, faeces, breast milk, hair, breath and saliva are considered separately. For each, methods appropriate for the analysis of drugs and metabolites, solvents and chemicals, anaesthetics, pesticides, organometallics and endogenous compounds are reviewed and the main experimental conditions outlined with specific examples. Then finally, the future potential of SPME for the analysis of biological samples in terms of the development of new devices and fibre chemistries and its coupling with high-performance liquid chromatography is discussed.

18. HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHIC DETERMINATION OF CAFFEIC ACID AND ROSMARINIC ACID FROM THE LEAVES OF Orthosiphon stamineus

Directory of Open Access Journals (Sweden)

2010-06-01

Full Text Available This paper presents the studies performed on extraction of Orthosiphon stamineus, Benth by using different solvent for the identification and quantification of the caffeic acid derivatives such as caffeic acid  and rosmarinic acid which confers to the leaves of this plant with remarkable pharmaceutical properties. High performance thin-layer chromatographic (HPTLC allows the identification and the quantification of more than 20 samples in the same chromatographic run. The analysis of the samples requires 15-30 min compared with more than 2 h using a typical HPLC method. Using the techniques of the HPTLC and the UV-VIS spectra we have found that the extraction of this herb plant contain, the caffeic acid and rosmarinic acid ranging between 0.029% up to 0.506% and up to 0.24% to 2.24% respectively.     Keywords: Caffice acid derivatives, quantification, Malaysian Orthosiphon stamineus, HPTLC

19. Chromatographic methods for analysis of triazine herbicides.

Science.gov (United States)

Abbas, Hana Hassan; Elbashir, Abdalla A; Aboul-Enein, Hassan Y

2015-01-01

Gas chromatography (GC) and high-performance liquid chromatography (HPLC) coupled to different detectors, and in combination with different sample extraction methods, are most widely used for analysis of triazine herbicides in different environmental samples. Nowadays, many variations and modifications of extraction and sample preparation methods such as solid-phase microextraction (SPME), hollow fiber-liquid phase microextraction (HF-LPME), stir bar sportive extraction (SBSE), headspace-solid phase microextraction (HS-SPME), dispersive liquid-liquid microextraction (DLLME), dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO), ultrasound-assisted emulsification microextraction (USAEME), and others have been introduced and developed to obtain sensitive and accurate methods for the analysis of these hazardous compounds. In this review, several analytical properties such as linearity, sensitivity, repeatability, and accuracy for each developed method are discussed, and excellent results were obtained for the most of developed methods combined with GC and HPLC techniques for the analysis of triazine herbicides. This review gives an overview of recent publications of the application of GC and HPLC for analysis of triazine herbicides residues in various samples.

20. Bowel sparing in pediatric cranio-spinal radiotherapy: a comparison of combined electron and photon and helical TomoTherapy techniques to a standard photon method

International Nuclear Information System (INIS)

Harron, Elizabeth; Lewis, Joanne

2012-01-01

The aim of this study was to compare the dose to organs at risk (OARs) from different craniospinal radiotherapy treatment approaches available at the Northern Centre for Cancer Care (NCCC), with a particular emphasis on sparing the bowel. Method: Treatment plans were produced for a pediatric medulloblastoma patient with inflammatory bowel disease using 3D conformal 6-MV photons (3DCP), combined 3D 6-MV photons and 18-MeV electrons (3DPE), and helical photon TomoTherapy (HT). The 3DPE plan was a modification of the standard 3DCP technique, using electrons to treat the spine inferior to the level of the diaphragm. The plans were compared in terms of the dose-volume data to OARs and the nontumor integral dose. Results: The 3DPE plan was found to give the lowest dose to the bowel and the lowest nontumor integral dose of the 3 techniques. However, the coverage of the spine planning target volume (PTV) was least homogeneous using this technique, with only 74.6% of the PTV covered by 95% of the prescribed dose. HT was able to achieve the best coverage of the PTVs (99.0% of the whole-brain PTV and 93.1% of the spine PTV received 95% of the prescribed dose), but delivered a significantly higher integral dose. HT was able to spare the heart, thyroid, and eyes better than the linac-based techniques, but other OARs received a higher dose. Conclusions: Use of electrons was the best method for reducing the dose to the bowel and the integral dose, at the expense of compromised spine PTV coverage. For some patients, HT may be a viable method of improving dose homogeneity and reducing selected OAR doses.

1. A Selective High Performance Liquid Chromatographic Method to Follow the Hydrolytic Degradation of Nicardipine Hydrochloride

Directory of Open Access Journals (Sweden)

K. E. Ibrahim

2010-01-01

Full Text Available A simple, stability indicating, reverse phase high performance liquid chromatographic method was developed and validated for determination of nicardipine hydrochloride (NC in the presence of its degradation products. The chromatographic separation was performed on Hypersil, BDS-C18, 30 cm × 3.9 mm id, at ambient temperature with UV-detection at 254 nm. A mixture of 20% (v/v aqueous 0.01 M sodium acetate∕acetic acid buffer (pH 4.5 and 80% acetonitrile was used as the mobile phase at a flow rate of 1.5 mL min-1, losartan was used as internal standard. The calibration curve is linear over the concentration range 5-40 μg mL-1, with a regression coefficient of 0.9984 and the % recovery was 99.78±0.17. The method was used to investigate the kinetics of alkaline, acids induced degradation, effect of buffer concentration and temperature. The degradation followed first-order kinetics. The rate constant, half-life time, and activation energy were calculated

2. Liquid chromatographic and spectrophotometric methods for the determination of erythromycin stearate and trimethoprim in tablets

Directory of Open Access Journals (Sweden)

Sonia T. Hassib

2011-12-01

Full Text Available Simple, accurate and precise reversed-phase liquid chromatographic (LC and spectrophotometric methods have been developed and validated for the determination of erythromycin stearate (ERS and trimethoprim (TMP in mixture. In LC method, chromatographic separation was achieved on a Symmetry® Waters C18 column (150 × 4.6 mm, 5 μm based on isocratic elution using a mobile phase consisting of potassium dihydrogen phosphate buffer pH (9:acetonitrile:water (25:100:50, v/v/v at a flow rate of 1.6 ml min−1 with UV detection at 210 nm for ERS and 280 nm for TMP. Besides, two spectrophotometric methods were applied after reaction with perchloric acid (12 M which gives a colored product with ERS. Then, the spectral interference between the colored product of ERS and TMP was resolved by either ratio spectra derivative spectrophotometry in the first spectrophotometric method or chemometric techniques, namely classical least-squares (CLS, principal component regression (PCR and partial least-squares regression (PLS in the second spectrophotometric method. The results were statistically compared using one-way analysis of variance (ANOVA. The methods developed were satisfactorily applied to the analysis of the pharmaceutical preparation containing the two drugs and proved to be specific and accurate for the quality control of the cited drugs in pharmaceutical dosage forms.

3. Chemometrics and chromatographic fingerprints to classify plant food supplements according to the content of regulated plants.

Science.gov (United States)

Deconinck, E; Sokeng Djiogo, C A; Courselle, P

2017-09-05

Plant food supplements are gaining popularity, resulting in a broader spectrum of available products and an increased consumption. Next to the problem of adulteration of these products with synthetic drugs the presence of regulated or toxic plants is an important issue, especially when the products are purchased from irregular sources. This paper focusses on this problem by using specific chromatographic fingerprints for five targeted plants and chemometric classification techniques in order to extract the important information from the fingerprints and determine the presence of the targeted plants in plant food supplements in an objective way. Two approaches were followed: (1) a multiclass model, (2) 2-class model for each of the targeted plants separately. For both approaches good classification models were obtained, especially when using SIMCA and PLS-DA. For each model, misclassification rates for the external test set of maximum one sample could be obtained. The models were applied to five real samples resulting in the identification of the correct plants, confirmed by mass spectrometry. Therefore chromatographic fingerprinting combined with chemometric modelling can be considered interesting to make a more objective decision on whether a regulated plant is present in a plant food supplement or not, especially when no mass spectrometry equipment is available. The results suggest also that the use of a battery of 2-class models to screen for several plants is the approach to be preferred. Copyright © 2017 Elsevier B.V. All rights reserved.

4. Determination of drugs in biological fluids by direct injection of samples for liquid-chromatographic analysis.

Science.gov (United States)

Mullett, Wayne M

2007-03-10

The analysis of drugs in various biological fluids is an important criterion for the determination of the physiological performance of a drug. After sampling of the biological fluid, the next step in the analytical process is sample preparation. The complexity of biological fluids adds to the challenge of direct determination of the drug by chromatographic analysis, therefore demanding a sample preparation step that is often time-consuming, tedious, and frequently overlooked. However, direct on-line injection methods offer the advantage of reducing sample preparation steps and enabling effective pre-concentration and clean-up of biological fluids. These procedures can be automated and therefore reduce the requirements for handling potentially infectious biomaterial, improve reproducibility, and minimize sample manipulations and potential contamination. The objective of this review is to present an overview of the existing literature with emphasis on advances in automated sample preparation methods for liquid-chromatographic methods. More specifically, this review concentrates on the use of direct injection techniques, such as restricted-access materials, turbulent-flow chromatography and other automated on-line solid-phase extraction (SPE) procedures. It also includes short overviews of emerging automated extraction-phase technologies, such as molecularly imprinted polymers, in-tube solid-phase micro-extraction, and micro-extraction in a packed syringe for a more selective extraction of analytes from complex samples, providing further improvements in the analysis of biological materials. Lastly, the outlook for these methods and potential new applications for these technologies are briefly discussed.

5. Warping methods for spectroscopic and chromatographic signal alignment: a tutorial.

Science.gov (United States)

Bloemberg, Tom G; Gerretzen, Jan; Lunshof, Anton; Wehrens, Ron; Buydens, Lutgarde M C

2013-06-05

Warping methods are an important class of methods that can correct for misalignments in (a.o.) chemical measurements. Their use in preprocessing of chromatographic, spectroscopic and spectrometric data has grown rapidly over the last decade. This tutorial review aims to give a critical introduction to the most important warping methods, the place of warping in preprocessing and current views on the related matters of reference selection, optimization, and evaluation. Some pitfalls in warping, notably for liquid chromatography-mass spectrometry (LC-MS) data and similar, will be discussed. Examples will be given of the application of a number of freely available warping methods to a nuclear magnetic resonance (NMR) spectroscopic dataset and a chromatographic dataset. As part of the Supporting Information, we provide a number of programming scripts in Matlab and R, allowing the reader to work the extended examples in detail and to reproduce the figures in this paper. Copyright © 2013 Elsevier B.V. All rights reserved.

6. New portable micro gas chromatograph for environmental analysis

Energy Technology Data Exchange (ETDEWEB)

Overton, E.B.; Carney, K.R.; Dharmasena, H.P.; Mainga, A.M.; Ehrmann, U. [Louisiana State Univ., Baton Rouge, LA (United States). Inst. for Environmental Studies

1994-12-31

Efforts directed at developing a truly portable method for the analysis of semivolatile compounds have led to the construction and testing of a new generation of micro-GC instrumentation. Building on the successful application of microbore GC columns for in-field analysis of volatile organic compounds, the instrument development group at the LSU-Institute for Environmental Studies has developed a hand portable GC capable of analyzing samples containing compounds with retention indices (100% dimethylpolysiloxane column) up to at least 2,000 in less than 4 minutes, using less than 50 watts (peak) of electrical power. In addition to the ability to analyze semivolatile compounds, the chromatograph is capable of analyzing volatile organics competitively with the most sophisticated of the current commercial portable GCs. The presentation will evaluate chromatographic performance of the instrument at its latest stage of development and demonstrate some applications to environmental analysis using the prototype instrument.

7. Analysis of soil and sewage sludge by ICP-OES and the German standard DIN 38414 sample preparation technique (P3)

International Nuclear Information System (INIS)

Edlund, M.; Heitland, P.; Visser, H.

2002-01-01

Full text: The elemental analyses of soil and sewage sludge has developed to become one of the main applications for ICP optical emission spectrometry (ICP-OES) and is described in many official procedures. These methods include different acid mixtures and digestion techniques. Even though the German standard DIN 38414 part 7 and the Dutch NEN 6465 do not guarantee complete recoveries for all elements, they are widely accepted in Europe. This paper describes sample preparation, line selection and investigates precision, accuracy and Limits of detection. The SPECTRO CIROSCCD EOP with axial plasma observation and the SPECTRO CIROSCCD SOP with radial observation were compared and evaluated for the analyses of soil and sewage sludge. Accuracy was investigated using the certified reference materials CRM-141 R, CRM-143 R and GSD 11. Both instruments show excellent performance in terms of speed, precision, accuracy and detection limits for the determination of trace metals in soil and sewage sludge. (author)

8. New overlay measurement technique with an i-line stepper using embedded standard field image alignment marks for wafer bonding applications

Science.gov (United States)

Kulse, P.; Sasai, K.; Schulz, K.; Wietstruck, M.

2017-06-01

In the last decades the semiconductor technology has been driven by Moore's law leading to high performance CMOS technologies with feature sizes of less than 10 nm [1]. It has been pointed out that not only scaling but also the integration of novel components and technology modules into CMOS/BiCMOS technologies is becoming more attractive to realize smart and miniaturized systems [2]. Driven by new applications in the area of communication, health and automation, new components and technology modules such as BiCMOS embedded RF-MEMS, high-Q passives, Sibased microfluidics and InP-SiGe BiCMOS heterointegration have been demonstrated [3-6]. In contrast to standard VLSI processes fabricated on front side of the silicon wafer, these new technology modules require addition backside processing of the wafer; thus an accurate alignment between the front and backside of the wafer is mandatory. In previous work an advanced back to front side alignment technique and implementation into IHP's 0.25/0.13 μm high performance SiGe:C BiCMOS backside process module has been presented [7]. The developed technique enables a high resolution and accurate lithography on the backside of BiCMOS wafer for additional backside processing. In addition to the aforementioned back side process technologies, new applications like Through-Silicon Vias (TSV) for interposers and advanced substrate technologies for 3D heterogeneous integration demand not only single wafer fabrication but also processing of wafer stacks provided by temporary and permanent wafer bonding [8]. Therefore, the available overlay measurement techniques are not suitable if overlay and alignment marks are realized at the bonding interface of a wafer stack which consists of both a silicon device and a silicon carrier wafer. The former used EVG 40NT automated overlay measurement system, which use two opposite positioned microscopes inspecting simultaneous the wafer back and front side, is not capable measuring embedded overlay

9. Liquid chromatographic-tandem mass spectrometric assay for ...

African Journals Online (AJOL)

Methods: Blood and urine samples were obtained from healthy volunteers who admitted to not being on any medications. The investigated analytes were chromatographically separated on a C18 column (Luna®-PFP 100Å column, 50 mm × 2.0 mm i.d., 3.0 μm) with the aid of a mobile phase containing A; acetonitrile (ACN) ...

10. Reliability evaluation of high-performance, low-power FinFET standard cells based on mixed RBB/FBB technique

Science.gov (United States)

Wang, Tian; Cui, Xiaoxin; Ni, Yewen; Liao, Kai; Liao, Nan; Yu, Dunshan; Cui, Xiaole

2017-04-01

With shrinking transistor feature size, the fin-type field-effect transistor (FinFET) has become the most promising option in low-power circuit design due to its superior capability to suppress leakage. To support the VLSI digital system flow based on logic synthesis, we have designed an optimized high-performance low-power FinFET standard cell library based on employing the mixed FBB/RBB technique in the existing stacked structure of each cell. This paper presents the reliability evaluation of the optimized cells under process and operating environment variations based on Monte Carlo analysis. The variations are modelled with Gaussian distribution of the device parameters and 10000 sweeps are conducted in the simulation to obtain the statistical properties of the worst-case delay and input-dependent leakage for each cell. For comparison, a set of non-optimal cells that adopt the same topology without employing the mixed biasing technique is also generated. Experimental results show that the optimized cells achieve standard deviation reduction of 39.1% and 30.7% at most in worst-case delay and input-dependent leakage respectively while the normalized deviation shrinking in worst-case delay and input-dependent leakage can be up to 98.37% and 24.13%, respectively, which demonstrates that our optimized cells are less sensitive to variability and exhibit more reliability. Project supported by the National Natural Science Foundation of China (No. 61306040), the State Key Development Program for Basic Research of China (No. 2015CB057201), the Beijing Natural Science Foundation (No. 4152020), and Natural Science Foundation of Guangdong Province, China (No. 2015A030313147).

11. UPLC-ICP-MS - a fast technique for speciation analysis

DEFF Research Database (Denmark)

Bendahl, L.; Sturup, S.; Gammelgaard, Bente

2005-01-01

Ultra performance liquid chromatography is a new development of the HPLC separation technique that allows separations on column materials at high pressures up to 10(8) Pa using particle diameters of 1.7 mu m. This increases the efficiency, the resolution and the speed of the separation. Four...... aqueous selenium standards were separated within 1.2 min on a 1.00 id x 50 mm reversed phase column in an ion-pair chromatographic system using a flow rate of 200 mu L min(-1). Hence, analysis times could be reduced to 1/10 compared with ordinary HPLC for aqueous standards. The precision and detection...... the use of short columns. Hence, analysis times could be halved without loss of separation efficiency in this biological sample...

12. Analysis of diatomaceous earth by x-ray fluorescence techniques

International Nuclear Information System (INIS)

Parker, J.

1985-01-01

The use of diatomaceous earth in industry as filtering aids, mineral fillers, catalyst carriers, chromatographic supports, and paint additives is well documented. The diatomite matrix is well suited to x-ray analysis, but this application has not been cited in the literature. In our laboratory, x-ray fluorescence spectrometry has been used to support the analytical needs of diatomite product development. Lithium borate fusion and pressed powder techniques have been used to determine major, minor, and trace elements in diatomite and synthetic silicate samples. Conventional matrix correction models and fundamental parameters have been used to reduce x-ray measurements to accurate chemical analyses. Described are sample and standard preparation techniques, data reduction methods, applications, and results

13. Suction/inspiration against resistance or standardized Mueller maneuver: a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

International Nuclear Information System (INIS)

Gutzeit, Andreas; Froehlich, Johannes M.; Weymarn, Constantin von; Goyen, Matthias; Waelti, Stephan; Roos, Justus E.; Meissnitzer, Matthias; Hergan, Klaus; Czell, David; Reischauer, Carolin

2015-01-01

Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. (orig.)

14. Suction/inspiration against resistance or standardized Mueller maneuver: a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study

Energy Technology Data Exchange (ETDEWEB)

Gutzeit, Andreas [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland); Kantonsspital Winterthur, Department of Radiology, Winterthur (Switzerland); Froehlich, Johannes M.; Weymarn, Constantin von; Goyen, Matthias [Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland); Waelti, Stephan [Cantonal Hospital St. Gallen, Department of Radiology and Nuclear Medicine, St. Gallen (Switzerland); Roos, Justus E. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Meissnitzer, Matthias; Hergan, Klaus [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Czell, David [Cantonal Hospital Winterthur, Department of Neurology, Winterthur (Switzerland); Reischauer, Carolin [Paracelsus Medical University Salzburg, Department of Radiology, Salzburg (Austria); Hirslanden Hospital St. Anna, Institute of Radiology and Nuclear Medicine, Clinical Research Unit, Lucerne (Switzerland)

2015-11-15

Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. (orig.)

15. Expression of human immunodeficiency virus (HIV) in naturally infected peripheral blood mononuclear cells: comparison of a standard co-culture technique with a newly developed microculture method.

Science.gov (United States)

Eberlein, B; Baur, A; Neundorfer, M; Jahn, G

1991-05-01

Peripheral blood mononuclear cells (PBMCs) from 29 patients infected with human immunodeficiency virus (HIV) were cultured by two different methods. One was the standard co-culture technique, the other a newly developed microculture method. In this assay 10(6) PBMCs were cultivated in 250 microliters medium, no activating agents or allogeneic cells were present. P24 antigen production measured by this method was found in 7 out of 11 PBMC cultures of patients in the Walter Reed (WR) stage 1 or 2, whereas only 4 samples were positive by the co-culture procedure. Cultures from patients in the later stages of the disease (WR 5/6) showed a higher p24 production by the co-culture method than by the microculture assay. It is assumed that rapidly growing HIV strains can be better assessed by the co-culture method which may select for these strains. P24 expression can be more easily obtained by the microculture technique even in cases where slowly replicating strains may be present. In conclusion, results from the microculture procedure described may be a useful supplementation to findings observed by the co-culture method.

16. Ultra-high performance liquid chromatographic determination of antioxidants in teas using inkjet-printed graphene-polyaniline electrode.

Science.gov (United States)

Bardpho, Chayanee; Rattanarat, Poomrat; Siangproh, Weena; Chailapakul, Orawon

2016-02-01

A development of ultra-high performance liquid chromatographic coupled with a novel inkjet-printed conductive ink-modified electrode for a fast and simultaneous determination of polyphenolic antioxidants was achieved. Two printing techniques were selected for fabrication and modification including (i) an in-house screen-printing method and (ii) an inkjet-printing method, respectively. A conductive ink containing graphene and polyaniline nanocomposite (G-PANI) was precisely casted onto the surface of screen-printed carbon electrode (SPCE) using a dimatix inkjet material printer. Compared to a bare SPCE, the G-PANI-modified screen-printed carbon electrode (G-PANI/SPCE) exhibited higher electrochemical sensitivity with increase (2-4 times) of peak current of each antioxidant. Moreover, four antioxidants were successfully separated and determined within 3 min using a reverse phase ultra-high performance liquid chromatography (UHPLC) with a mobile phase containing phosphate buffer and acetonitrile (90:10 v/v). Under an optimal detection potential at +1.2V vs. Ag/AgCl, linear calibrations and limits of detection (S/N=3) for antioxidants were found to be 0.01-10 µg mL(-1) and 1.38-1.94 ng mL(-1), respectively. Finally, this proposed method has been successfully used for the determination of antioxidants in tea samples, the results obtained from our presented method were within a highly good agreement those obtained from a standard UHPLC-UV method. Copyright © 2015 Elsevier B.V. All rights reserved.

17. Technical Note: Precise quantitative measurements of total dissolved inorganic carbon from small amounts of seawater using a gas chromatographic system

Directory of Open Access Journals (Sweden)

T. Hansen

2013-10-01

Full Text Available Total dissolved inorganic carbon (CT is one of the most frequently measured parameters used to calculate the partial pressure of carbon dioxide in seawater. Its determination has become increasingly important because of the rising interest in the biological effects of ocean acidification. Coulometric and infrared detection methods are currently favored in order to precisely quantify CT. These methods however are not sufficiently validated for CT measurements of biological experiments manipulating seawater carbonate chemistry with an extended CT measurement range (~1250–2400 μmol kg–1 compared to natural open ocean seawater (~1950–2200 μmol kg−1. The requirement of total sample amounts between 0.1–1 L seawater in the coulometric- and infrared detection methods potentially exclude their use for experiments working with much smaller volumes. Additionally, precise CT analytics become difficult with high amounts of biomass (e.g., phytoplankton cultures or even impossible in the presence of planktonic calcifiers without sample pre-filtration. Filtration however, can alter CT concentration through gas exchange induced by high pressure. Addressing these problems, we present precise quantification of CT using a small, basic and inexpensive gas chromatograph as a CT analyzer. Our technique is able to provide a repeatability of ±3.1 μmol kg−1, given by the pooled standard deviation over a CT range typically applied in acidification experiments. 200 μL of sample is required to perform the actual CT measurement. The total sample amount needed is 12 mL. Moreover, we show that sample filtration is applicable with only minor alteration of the CT. The method is simple, reliable and with low cumulative material costs. Hence, it is potentially attractive for all researchers experimentally manipulating the seawater carbonate system.

18. Application of power functions to chromatographic data for the enhancement of signal to noise ratios and separation resolution.

Science.gov (United States)

Shalliker, R A; Stevenson, P G; Shock, D; Mnatsakanyan, M; Dasgupta, P K; Guiochon, G

2010-09-03

Chromatographic detection responses are recorded digitally. A peak is represented ideally by a Guassian distribution. Raising a Guassian distribution to the power 'n' increases the height of the peak to that power, but decreases the standard deviation by radicaln. Hence there is an increasing disparity in detection responses as the signal moves from low level noise, with a corresponding decrease in peak width. This increases the S/N ratio and increases peak to peak resolution. The ramifications of these factors are that poor resolution in complex chromatographic data can be improved, and low signal responses embedded at near noise levels can be enhanced. The application of this data treatment process is potentially very useful in 2D-HPLC where sample dilution occurs between dimension, reducing signal response, and in the application of post-reaction detection methods, where band broadening is increased by virtue of reaction coils. In this work power functions applied to chromatographic data are discussed in the context of (a) complex separation problems, (b) 2D-HPLC separations, and (c) post-column reaction detectors. 2010 Elsevier B.V. All rights reserved.

19. Determination and discrimination of biodiesel fuels by gas chromatographic and chemometric methods

Directory of Open Access Journals (Sweden)

Milina R.

2016-03-01

Full Text Available Pattern recognition method (PRM was applied to gas chromatographic (GC data for a fatty acid methyl esters (FAME composition of commercial and laboratory synthesized biodiesel fuels from vegetable oils including sunflower, rapeseed, corn and palm oils. Two GC quantitative methods to calculate individual fames were compared: Area % and internal standard. The both methods were applied for analysis of two certified reference materials. The statistical processing of the obtained results demonstrates the accuracy and precision of the two methods and allows them to be compared. For further chemometric investigations of biodiesel fuels by their FAME-profiles any of those methods can be used. PRM results of FAME profiles of samples from different vegetable oils show a successful recognition of biodiesels according to the feedstock. The information obtained can be used for selection of feedstock to produce biodiesels with certain properties, for assessing their interchangeability, for fuel spillage and remedial actions in the environment.

20. Determination and discrimination of biodiesel fuels by gas chromatographic and chemometric methods

Science.gov (United States)

Milina, R.; Mustafa, Z.; Bojilov, D.; Dagnon, S.; Moskovkina, M.

2016-03-01

Pattern recognition method (PRM) was applied to gas chromatographic (GC) data for a fatty acid methyl esters (FAME) composition of commercial and laboratory synthesized biodiesel fuels from vegetable oils including sunflower, rapeseed, corn and palm oils. Two GC quantitative methods to calculate individual fames were compared: Area % and internal standard. The both methods were applied for analysis of two certified reference materials. The statistical processing of the obtained results demonstrates the accuracy and precision of the two methods and allows them to be compared. For further chemometric investigations of biodiesel fuels by their FAME-profiles any of those methods can be used. PRM results of FAME profiles of samples from different vegetable oils show a successful recognition of biodiesels according to the feedstock. The information obtained can be used for selection of feedstock to produce biodiesels with certain properties, for assessing their interchangeability, for fuel spillage and remedial actions in the environment.

1. Current Applications of Chromatographic Methods in the Study of Human Body Fluids for Diagnosing Disorders.

Science.gov (United States)

Jóźwik, Jagoda; Kałużna-Czaplińska, Joanna

2016-01-01

Currently, analysis of various human body fluids is one of the most essential and promising approaches to enable the discovery of biomarkers or pathophysiological mechanisms for disorders and diseases. Analysis of these fluids is challenging due to their complex composition and unique characteristics. Development of new analytical methods in this field has made it possible to analyze body fluids with higher selectivity, sensitivity, and precision. The composition and concentration of analytes in body fluids are most often determined by chromatography-based techniques. There is no doubt that proper use of knowledge that comes from a better understanding of the role of body fluids requires the cooperation of scientists of diverse specializations, including analytical chemists, biologists, and physicians. This article summarizes current knowledge about the application of different chromatographic methods in analyses of a wide range of compounds in human body fluids in order to diagnose certain diseases and disorders.

2. High-performance liquid chromatographic determination of levodropropizine in human plasma with fluorometric detection.

Science.gov (United States)

Tagliaro, F; Moffa, M; De Battisti, Z; Smith, F P; Gentile, M

1996-10-11

The present paper describes a new high-performance liquid chromatographic method with fluorescence detection for the analysis of levodropropizine [S-(-)-3-(4-phenylpiperazin-1-yl)-propane-1,2-diol] (Levotuss), an anti-tussive drug, in human serum and plasma. A reversed-phase separation of levodropropizine was coupled with detection of the native fluorescence of the molecule, using excitation and emission wavelengths of 240 nm and 350 nm respectively. The analytical column was packed with spherical 5 microns poly(styrene-divinylbenzene) particles and the mobile phase was 0.1 M NaH2PO4 pH 3-methanol (70:30, v/v), containing 0.5% (v/v) tetrahydrofuran. For quantitation, p-methoxylevodropropizine was used as the internal standard. Samples of 200 microliters of either serum or plasma were mixed with 200 microliters of 0.1 M Na2HPO4 pH 8.9 and extracted with 5 ml of chloroform-2-propanol (9:1, v/v). The dried residue from the organic extract was redissolved with distilled water and directly injected into the chromatograph. The limit of detection for levodropropizine, in biological matrix, was about 1-2 ng/ml, at a signal-to-noise ratio of 3. The linearity was satisfactory over a range of concentrations from 3 to 1000 ng/ml (r2 = 0.99910); within-day precision tested in the range 5-100 ng/ml as well as day-to-day reproducibility proved acceptable, with relative standard deviations better than 1% in most cases. Interferences from as many as 91 therapeutic or illicit drugs were excluded.

3. Chromatographic and electrophoretic methods for the analysis of phenethylamine [corrected] alkaloids in Citrus aurantium.

Science.gov (United States)

Pellati, Federica; Benvenuti, Stefania

2007-08-17

Citrus aurantium (bitter orange) is a plant belonging to the family Rutaceae, whose fruit extracts have been used recently for the treatment of obesity. The most important biologically active constituents of the C. aurantium fruits are phenethylamine alkaloids (i.e. octopamine, synephrine, tyramine, N-methyltyramine and hordenine). Synephrine is a primary synthesis compound with pharmacological activities such as vasoconstriction, elevation of blood pressure and relaxation of bronchial muscle. Synephrine is present in the peel and the edible part of Citrus fruit. Of the adrenergic amines of natural origin, synephrine has been found to be the main constituent of C. aurantium fruits and extracts; the other alkaloids are either absent or present in only low concentrations. It is known that synephrine and the other amines found in C. aurantium have adverse effects on the cardiovascular system, owing to adrenergic stimulation. In light of the great commercial proliferation of C. aurantium herbal medicines in recent years, this review provides an overview of various extraction, separation and detection techniques employed for the qualitative and quantitative determination of the alkaloids in C. aurantium and related species. The application of chromatographic and electrophoretic methods for the separation and determination of these active components in C. aurantium plant material and derivatives are described. Since synephrine is a chiral compound, enantioselective chromatographic and electrophoretic techniques for the analysis of synephrine enantiomers in natural products are presented. Furthermore, examples of identification of these active compounds in complex matrices by hyphenated methods, such as gas chromatography-mass spectrometry and high-performance liquid chromatography-mass spectrometry, are described. The advantages and limitations of these separation and identification methods are assessed and discussed.

4. Design and Performance of a Gas Chromatograph for Automatic Monitoring of Pollutants in Ambient Air

Science.gov (United States)

Villalobos, R.; Stevens, D.; LeBlanc, R.; Braun, L.

1971-01-01

In recent years, interest in air pollution constituents has focused on carbon monoxide and hydrocarbons as prime components of polluted air. Instrumental methods have been developed, and commercial instruments for continuous monitoring of these components have been available for a number of years. For the measurement of carbon monoxide, non-dispersive infrared spectroscopy has been the accepted tool, in spite of its marginal sensitivity at low parts-per-million levels. For continuously monitoring total hydrocarbons, the hydrogen flame ionization analyzer has been widely accepted as the preferred method. The inadequacy of this latter method became evident when it was concluded that methane is non-reactive and cannot be considered a contaminant even though present at over 1 ppm in the earth's atmosphere. Hence, the need for measuring methane separately became apparent as a means of measuring the reactive and potentially harmful non-methane hydrocarbons fraction. A gas chromatographic method for the measurement of methane and total hydrocarbons which met these requirements has been developed. In this technique, methane was separated on conventional gas chromatographic columns and detected by a hydrogen flame ionization detector (FID) while the total hydrocarbons were obtained by introducing a second sample directly into the FID without separating the various components. The reactive, or non-methane hydrocarbons, were determined by difference. Carbon monoxide was also measured after converting to methane over a heated catalyst to render it detectable by the FID. The development of this method made it possible to perform these measurements with a sensitivity of as much as 1 ppm full scale and a minimum detectability of 20 ppb. Incorporating this technique, criteria were developed by APCO for a second generation continuous automatic instrument for atmospheric monitoring stations.

5. Determination of Bitter Orange alkaloids in dietary supplements standard reference materials by liquid chromatography with ultraviolet absorbance and fluorescence detection.

Science.gov (United States)

Putzbach, Karsten; Rimmer, Catherine A; Sharpless, Katherine E; Sander, Lane C

2007-07-13

Four adrenergic amines [synephrine, octopamine, tyramine, and n-methyltyramine] were determined in a variety of Bitter Orange containing dietary supplements. Two extraction techniques were evaluated in detail: Soxhlet extraction and sonication extraction. A liquid chromatographic separation using a reversed-phase C(18) stationary phase and the ion-pairing reagent sodium dodecyl sulfate was developed to separate the Bitter Orange alkaloids. Ultraviolet absorbance detection at 220 nm and fluorescence detection with excitation at 273 nm and emission at 304 nm were used for the alkaloid detection. The method described was used for the assignment of the levels of the predominant alkaloids in three candidate standard reference materials containing Bitter Orange.

6. Suction/Inspiration against resistance or standardized Mueller maneuver : a new breathing technique to improve contrast density within the pulmonary artery: a pilot CT study.

Science.gov (United States)

Gutzeit, Andreas; Froehlich, Johannes M; Wälti, Stephan; Roos, Justus E; Meissnitzer, Matthias; Hergan, Klaus; von Weymarn, Constantin; Czell, David; Goyen, Matthias; Reischauer, Carolin

2015-11-01

Our aim was to prospectively investigate whether the recently introduced suction/inspiration against resistance breathing method leads to higher computed tomography (CT) contrast density in the pulmonary artery compared to standard breathing. The present study was approved by the Medical Ethics committee and all subjects gave written informed consent. Fifteen patients, each without suspicious lung emboli, were randomly assigned to four different groups with different breathing maneuvers (suction against resistance, Valsalva, inspiration, expiration) during routine CT. Contrast enhancement in the central and peripheral sections of the pulmonary artery were measured and compared with one another. Peripheral enhancement during suction yielded increased mean densities of 138.14 Hounsfield units (HU) (p = 0.001), compared to Valsalva and a mean density of 67.97 HU superior to inspiration (p = 0.075). Finally, suction in comparison to expiration resulted in a mean increase of 30.51 HU (p = 0.42). Central parts of pulmonary arteries presented significantly increased enhancement values (95.74 HU) for suction versus the Valsalva technique (p = 0.020), while all other mean densities were in favour of suction (versus inspiration: p = 0.201; versus expiration: p = 0.790) without reaching significance. Suction/Inspiration against resistance is a promising technique to improve contrast density within pulmonary vessels, especially in the peripheral parts, in comparison to other breathing maneuvers. • Suction/Inspiration against resistance is promising to improve contrast density within the pulmonary artery. • Patients potentially suffering pulmonary embolism are able to follow suction/inspiration against resistance. • Contrast density after suction is superior in comparison to other breathing maneuvers.

7. SU-F-T-503: Trajectory Modulated Arc Therapy of Intracranial Lesions: Development of a Standardized Path-Based Technique for Fully Dynamic Couch-Gantry Modulated Treatments

Energy Technology Data Exchange (ETDEWEB)

Khan, S; Chin, E; Xing, L; Hristov, D; Fahimian, B [Stanford University, Stanford, CA (United States); Otto, K [University of British Columbia, Victoria (Canada)

2016-06-15

Purpose: The integration of couch motion during arc delivery is necessitated to enable irradiation trajectories such as coronal arcs, and to enhance the geometrical sampling for dynamic deliveries to the highest extent. To enable such capability, a platform of Trajectory Modulated Arc Therapy (TMAT) is developed in conjunction with standardized noncollisional dynamic path-set for irradiation of intracranial lesions. Methods: A generalized path-set was constructed through the combination of sagittal arcs (45 degrees from the CAX), axial arcs, and coronal arcs produced through modulation of the dynamic rotation of couch. The standardized path was implemented in a contiguous manner enabling the formation of fully automated sub-trajectories to provide maximal geometrical convergence with minimal number of arcs. Progressive sampling technique is used for direct aperture optimization of the MLCs and the selection of couch positions across the control points. Dosimetry of the resulting plans was assessed relative to clinically delivered plans. Using the TrueBeam Developer Mode, plan deliverability was tested. Results: Treatment planning of TMAT sub-trajectories for central, anterior and posterior tumor sites with volumes ranging from 4.75cc to 107cc demonstrated radically reduced doses to the critical OARs when compared to the clinically treated VMAT. Specifically, percentage reduction in mean dose for critical organs such as brainstem, cochlea, and optic nerve are found to be as low as 74±15%, 50±26% and 74±30% respectively as compared to VMAT. Conformity Index, defined as the ratio of tumor volume (VPTV) and 100% dose volume (V(D100%)), was reduced up to 12% while the Gradient Index, defined as V(D100%)/V(D50%), was concurrently improved by up to 14%. Conclusion: An automated standardized trajectory with dynamically modulated couch-gantry arcs has been developed for intracranial radiotherapy. Through the incorporation of coronal arcs, it is demonstrated that

8. Chromatographic fingerprint similarity analysis for pollutant source identification

International Nuclear Information System (INIS)

Xie, Juan-Ping; Ni, Hong-Gang

2015-01-01

In the present study, a similarity analysis method was proposed to evaluate the source-sink relationships among environmental media for polybrominated diphenyl ethers (PBDEs), which were taken as the representative contaminants. Chromatographic fingerprint analysis has been widely used in the fields of natural products chemistry and forensic chemistry, but its application to environmental science has been limited. We established a library of various sources of media containing contaminants (e.g., plastics), recognizing that the establishment of a more comprehensive library allows for a better understanding of the sources of contamination. We then compared an environmental complex mixture (e.g., sediment, soil) with the profiles in the library. These comparisons could be used as the first step in source tracking. The cosine similarities between plastic and soil or sediment ranged from 0.53 to 0.68, suggesting that plastic in electronic waste is an important source of PBDEs in the environment, but it is not the only source. A similarity analysis between soil and sediment indicated that they have a source-sink relationship. Generally, the similarity analysis method can encompass more relevant information of complex mixtures in the environment than a profile-based approach that only focuses on target pollutants. There is an inherent advantage to creating a data matrix containing all peaks and their relative levels after matching the peaks based on retention times and peak areas. This data matrix can be used for source identification via a similarity analysis without quantitative or qualitative analysis of all chemicals in a sample. - Highlights: • Chromatographic fingerprint analysis can be used as the first step in source tracking. • Similarity analysis method can encompass more relevant information of pollution. • The fingerprints strongly depend on the chromatographic conditions. • A more effective and robust method for identifying similarities is required

9. Retention Study of Flavonoids Under Different Chromatographic Modes.

Science.gov (United States)

Sentkowska, Aleksandra; Biesaga, Magdalena; Pyrzynska, Krystyna

2016-04-01

The goal of this study was to investigate the chromatographic behavior of selected flavonoids from their different subgroups (flavonols, flavanones, flavones and isoflavones) in hydrophilic interaction liquid chromatography (HILIC). Chromatographic measurements were made on two different HILIC columns: cross-linked DIOL (Luna HILIC) and zwitterionic sulfoalkylbetaine (SeQuant ZIC-HILIC). Separation parameters such as the content of acetonitrile and pH of an eluent were studied. On the ZIC column, the retention factors of flavonoids increased with decreasing water content in the mobile phase. The increase in pH of the aqueous component mainly affects the polarity of the analytes. DIOL stationary phase shows more or less apparent dual retention mechanism, HILIC at the acetonitrile (ACN) content ≥75% and reversed phase (RP) with lower content of organic modifier. In the presence of ammonium acetate in the mobile phase, the retention of flavonoids onto the DIOL column increases without change in the selectivity of the separations. The similar effect, but considerably smaller was observed for aglycones on the ZIC column. The retention of studied glycosides (hesperidin, rutin) decreases in the presence of salt in the mobile phase. The significantly higher mass spectrometry sensitivity was observed under HILIC conditions in comparison with the most often used RP LC due to much higher content of ACN in the mobile phase. Finally, under optimal chromatographic conditions, the method was validated and applied for the determination of flavonoids in chamomile (Matricaria chamomilla L.) infusion. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

10. Quantitative structure-chromatographic retention correlations of quinoline derivatives.

Science.gov (United States)

Nekrasova, Nadezhda A; Kurbatova, Svetlana V

2017-04-07

The aim of our study was to investigate relationships between quinoline derivatives structure and their retention under reversed-phase liquid chromatography conditions. Retention factors of quinolines were experimentally measured and various geometrical and physicochemical parameters representing analytes molecular structure were calculated. Equations connecting chromatographic data with computed characteristics for the set of 17 investigated compounds were constructed. It was shown that the most precise dependencies include combination of physico-chemical and geometrical parameters. Copyright © 2017 Elsevier B.V. All rights reserved.

11. Chromatographic purification of tritiated steroids prior to use in radioimmunoassay

International Nuclear Information System (INIS)

Manlimos, F.S.; Abraham, G.E.

1975-01-01

The purity of tritiated steroids used as reagents in radioimmunoassay plays an important role in the reliability of the assay. These radioactive reagents should be assessed for purity upon receipt and the purity should be checked periodically afterward. For such purposes, we have used chromatographic purification on Celite microcolumns. By changing the polarity of the stationary and mobile phases, 20 different tritiated steroids with a wide range of polarity could be purified on these microcolumns. This approach is easy, rapid, economical, and reliable. (U.S.)

12. Gas chromatographic method fr determination of carbon in metallic uranium

International Nuclear Information System (INIS)

Nikol'skij, V.A.; Markov, V.K.; Evseeva, T.I.; Cherstvenkova, E.P.

1983-01-01

Gas chromatographic device to determine carbon in metal uranium is developed. Burnout unite, permitting to load in the burnout tube simultaneously quite a few (up to 20) weight amounts of materials to be burned is a characteristic feature of the device. As a result amendments for control experiment and determination limit are decreased. The time of a single determination is also reduced. Conditions of carbon burn out from metal uranium are studied and temperature and time of complete extraction of carbon in the form of dioxide from weight amount into gaseous phase are established

13. Analysis of vitamin D metabolic markers by mass spectrometry: current techniques, limitations of the "gold standard" method, and anticipated future directions.

Science.gov (United States)

Volmer, Dietrich A; Mendes, Luana R B C; Stokes, Caroline S

2015-01-01

Vitamin D compounds belong to a group of secosteroids, which occur naturally as vitamin D3 in mammals and D2 in plants. Vitamin D is vital for bone health but recent studies have shown a much wider role in the pathologies of diseases such as diabetes, cancer, autoimmune, neurodegenerative, mental and cardiovascular diseases. Photosynthesis of vitamin D in the human skin and subsequent hepatic and renal metabolism generate a wide range of transformation products occurring over a large dynamic range spanning from picomolar to nanomolar levels. This necessitates selective and sensitive analytical methods to quantitatively capture these low concentration levels in relevant tissues such as blood. Ideally, vitamin D assessment would be performed using a universal and standardized analytical method available to clinical laboratories that provides reliable and accurate quantitative results for all relevant vitamin D metabolites with sufficiently high throughput. At present, LC-MS/MS assays are the most promising techniques for vitamin D analysis. The present review focuses on developments in mass spectrometry methodologies of the past 12 years. It will highlight detrimental influences of the biological matrix, epimer contributions, pitfalls of specific mass spectrometry data acquisition routines (in particular multiple reaction monitoring, MRM), influence of ionization source, derivatization reactions, inter-laboratory comparisons on precision, accuracy, and application range of vitamin D metabolites. © 2013 Wiley Periodicals, Inc.

14. MDCT for suspected acute appendicitis in adults: impact of oral and IV contrast media at standard-dose and simulated low-dose techniques.

Science.gov (United States)

Keyzer, Caroline; Cullus, Pierre; Tack, Denis; De Maertelaer, Viviane; Bohy, Pascale; Gevenois, Pierre Alain

2009-11-01

The objective of this study was to prospectively investigate the influence of oral, IV, and oral and IV contrast media on the information provided by MDCT at standard and simulated low radiation doses in adults suspected of having acute appendicitis. One hundred thirty-one consecutive patients (80 women, 51 men; age range, 18-87 years; mean age, 37 years) suspected of having appendicitis were randomly assigned to either ingest or not ingest iodinated contrast material. Thereafter, all patients underwent IV unenhanced and enhanced abdominopelvic MDCT with a 4 x 2.5 mm collimation at 120 kVp and 100 mAs(eff). Dose reduction corresponding to 30 mAs(eff) was simulated. Two radiologists independently read scans during separate sessions, assessed appendix visualization, and proposed a diagnosis (i.e., appendicitis or an alternative diagnosis). The final diagnosis was based on either surgical findings or clinical follow-up. Data were analyzed by factorial analysis of multiple correspondences followed by an ascending hierarchic classification method. Factorial analysis and ascending hierarchic classification revealed that, in terms of diagnostic correctness, reader influence predominated over the influence of IV and oral contrast media use and radiation dose but that correctness was also influenced by the patient's sex (p = 0.048) and was lower in cases of alternative diseases (p technique.

15. Search for the Standard Model Higgs Boson associated with a W Boson using Matrix Element Technique in the CDF detector at the Tevatron

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, Barbara Alvarez [Univ. of Oviedo (Spain)

2010-05-01

In this thesis a direct search for the Standard Model Higgs boson production in association with a W boson at the CDF detector in the Tevatron is presented. This search contributes predominantly in the region of low mass Higgs region, when the mass of Higgs boson is less than about 135 GeV. The search is performed in a final state where the Higgs boson decays into two b quarks, and the W boson decays leptonically, to a charged lepton (it can be an electron or a muon) and a neutrino. This work is organized as follows. Chapter 2 gives an overview of the Standard Model theory of particle physics and presents the SM Higgs boson search results at LEP, and the Tevatron colliders, as well as the prospects for the SM Higgs boson searches at the LHC. The dataset used in this analysis corresponds to 4.8 fb-1 of integrated luminosity of p$\\bar{p}$ collisions at a center of mass energy of 1.96 TeV. That is the luminosity acquired between the beginning of the CDF Run II experiment, February 2002, and May 2009. The relevant aspects, for this analysis, of the Tevatron accelerator and the CDF detector are shown in Chapter 3. In Chapter 4 the particles and observables that make up the WH final state, electrons, muons, ET, and jets are presented. The CDF standard b-tagging algorithms to identify b jets, and the neural network flavor separator to distinguish them from other flavor jets are also described in Chapter 4. The main background contributions are those coming from heavy flavor production processes, such as those coming from Wbb, Wcc or Wc and tt. The signal and background signatures are discussed in Chapter 5 together with the Monte CArlo generators that have been used to simulate almost all the events used in this thesis. WH candidate events have a high-pT lepton (electron or muon), high missing transverse energy, and two or more than two jets in the final state. Chapter 6 describes the event selection applied in this analysis and the

16. Separation and determination of high-carbon alcohols using method of column chromatographic and gas-chromatographic analysis

International Nuclear Information System (INIS)

Kang Zhongrong; Li Biping; Zeng Yongchang

1988-01-01

This paper describes the separation and determination of high-carbon alcohols from amine extractant by using the method of column chromatography of aluminium oxide and gas-chromatographic analysis. The total conent of high-carbon alcohols is determined by the method of column chromatography, while the components of the high-carbon alcohols and their relative contents are determined by the method of gas-chromatography. A simple reliable and practical method is provided for the analysis of high-carbon alcohol from the amine extractant in this paper

17. Bone augmentation at peri-implant dehiscence defects comparing a synthetic polyethylene glycol hydrogel matrix vs. standard guided bone regeneration techniques.

Science.gov (United States)

Thoma, Daniel S; Jung, Ui-Won; Park, Jin-Young; Bienz, Stefan P; Hüsler, Jürg; Jung, Ronald E

2017-07-01

The aim of the study was to test whether or not the use of a polyethylene glycol (PEG) hydrogel with or without the addition of an arginylglycylaspartic acid (RGD) sequence applied as a matrix in combination with hydroxyapatite/tricalciumphosphate (HA/TCP) results in similar peri-implant bone regeneration as traditional guided bone regeneration procedures. In 12 beagle dogs, implant placement and peri-implant bone regeneration were performed 2 months after tooth extraction in the maxilla. Two standardized box-shaped defects were bilaterally created, and dental implants were placed in the center of the defects with a dehiscence of 4 mm. Four treatment modalities were randomly applied: i)HA/TCP mixed with a synthetic PEG hydrogel, ii)HA/TCP mixed with a synthetic PEG hydrogel supplemented with an RGD sequence, iii)HA/TCP covered with a native collagen membrane (CM), iv)and no bone augmentation (empty). After a healing period of 8 or 16 weeks, micro-CT and histological analyses were performed. Histomorphometric analysis revealed a greater relative augmented area for groups with bone augmentation (43.3%-53.9% at 8 weeks, 31.2%-42.8% at 16 weeks) compared to empty controls (22.9% at 8 weeks, 1.1% at 16 weeks). The median amount of newly formed bone was greatest in group CM at both time-points. Regarding the first bone-to-implant contact, CM was statistically significantly superior to all other groups at 8 weeks. Bone can partially be regenerated at peri-implant buccal dehiscence defects using traditional guided bone regeneration techniques. The use of a PEG hydrogel applied as a matrix mixed with a synthetic bone substitute material might lack a sufficient stability over time for this kind of defect. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

18. Compressed air injection technique to standardize block injection pressures : [La technique d'injection d'air comprimé pour normaliser les pressions d'injection d'un blocage nerveux].

Science.gov (United States)

Tsui, Ban C H; Li, Lisa X Y; Pillay, Jennifer J

2006-11-01

Presently, no standardized technique exists to monitor injection pressures during peripheral nerve blocks. Our objective was to determine if a compressed air injection technique, using an in vitro model based on Boyle's law and typical regional anesthesia equipment, could consistently maintain injection pressures below a 1293 mmHg level associated with clinically significant nerve injury. Injection pressures for 20 and 30 mL syringes with various needle sizes ( 18G, 20G, 21 G, 22G, and 24G) were measured in a closed system. A set volume of air was aspirated into a saline-filled syringe and then compressed and maintained at various percentages while pressure was measured. The needle was inserted into the injection port of a pressure sensor, which had attached extension tubing with an injection plug clamped "off". Using linear regression with all data points, the pressure value and 99% confidence interval (CI) at 50% air compression was estimated. The linearity of Boyle's law was demonstrated with a high correlation, r = 0.99, and a slope of 0.984 (99% CI: 0.967-1.001). The net pressure generated at 50% compression was estimated as 744.8 mmHg, with the 99% CI between 729.6 and 760.0 mmHg. The various syringe/needle combinations had similar results. By creating and maintaining syringe air compression at 50% or less, injection pressures will be substantially below the 1293 mmHg threshold considered to be an associated risk factor for clinically significant nerve injury. This technique may allow simple, real-time and objective monitoring during local anesthetic injections while inherently reducing injection speed. Présentement, aucune technique normalisée ne permet de vérifier les pressions d'injection pendant les blocages nerveux périphériques. Nous voulions vérifier si une technique d'injection d'air comprimé, utilisant un modèle in vitro fondé sur la loi de Boyle et du matériel propre à l'anesthésie régionale, pouvait maintenir avec régularité les

19. Multiplex gas chromatography: an alternative concept for gas chromatographic analysis of planetary atmospheres

Science.gov (United States)

Valentin, J. R.

1989-01-01

Gas chromatography (GC) is a powerful technique for analyzing gaseous mixtures. Applied to the earth's atmosphere, GC can be used to determine the permanent gases--such as carbon dioxide, nitrogen, and oxygen--and to analyze organic pollutants in air. The U.S. National Aeronautics and Space Administration (NASA) has used GC in spacecraft missions to Mars (the Viking Biology Gas Exchange Experiment [GEX] and the Viking Gas Chromatograph-Mass Spectrometer [GC-MS]) and to Venus (the Pioneer Venus Gas Chromatograph [PVGC] on board the Pioneer Venus sounder probe) for determining the atmospheric constituents of these two planets. Even though conventional GC was very useful in the Viking and Pioneer missions, spacecraft constraints and limitations intrinsic to the technique prevented the collection of more samples. With the Venus probe, for instance, each measurement took a relatively long time to complete (10 min), and successive samples could not be introduced until the previous samples had left the column. Therefore, while the probe descended through the Venusian atmosphere, only three samples were acquired at widely separated altitudes. With the Viking mission, the sampling rate was not a serious problem because samples were acquired over a period of one year. However, the detection limit was a major disadvantage. The GC-MS could not detect simple hydrocarbons and simple alcohols below 0.1 ppm, and the GEX could not detect them below 1 ppm. For more complex molecules, the detection limits were at the parts-per-billion level for both instruments. Finally, in both the Viking and Pioneer missions, the relatively slow rate of data acquisition limited the number of analyses, and consequently, the amount of information returned. Similar constraints are expected in future NASA missions. For instance, gas chromatographic instrumentation is being developed to collect and analyze organic gases and aerosols in the atmosphere of Titan (one of Saturn's satellites). The Titan

20. Similarity analyses of chromatographic herbal fingerprints: A review

International Nuclear Information System (INIS)

Goodarzi, Mohammad; Russell, Paul J.; Vander Heyden, Yvan

2013-01-01

Graphical abstract: -- Highlights: •Similarity analyses of herbal fingerprints are reviewed. •Different (dis)similarity approaches are discussed. •(Dis)similarity-metrics and exploratory-analysis approaches are illustrated. •Correlation and distance-based measures are overviewed. •Similarity analyses illustrated by several case studies. -- Abstract: Herbal medicines are becoming again more popular in the developed countries because being “natural” and people thus often assume that they are inherently safe. Herbs have also been used worldwide for many centuries in the traditional medicines. The concern of their safety and efficacy has grown since increasing western interest. Herbal materials and their extracts are very complex, often including hundreds of compounds. A thorough understanding of their chemical composition is essential for conducting a safety risk assessment. However, herbal material can show considerable variability. The chemical constituents and their amounts in a herb can be different, due to growing conditions, such as climate and soil, the drying process, the harvest season, etc. Among the analytical methods, chromatographic fingerprinting has been recommended as a potential and reliable methodology for the identification and quality control of herbal medicines. Identification is needed to avoid fraud and adulteration. Currently, analyzing chromatographic herbal fingerprint data sets has become one of the most applied tools in quality assessment of herbal materials. Mostly, the entire chromatographic profiles are used to identify or to evaluate the quality of the herbs investigated. Occasionally only a limited number of compounds are considered. One approach to the safety risk assessment is to determine whether the herbal material is substantially equivalent to that which is either readily consumed in the diet, has a history of application or has earlier been commercialized i.e. to what is considered as reference material. In order

1. Similarity analyses of chromatographic herbal fingerprints: A review

Energy Technology Data Exchange (ETDEWEB)

Goodarzi, Mohammad [Department of Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels (Belgium); Russell, Paul J. [Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ (United Kingdom); Vander Heyden, Yvan, E-mail: yvanvdh@vub.ac.be [Department of Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels (Belgium)

2013-12-04

Graphical abstract: -- Highlights: •Similarity analyses of herbal fingerprints are reviewed. •Different (dis)similarity approaches are discussed. •(Dis)similarity-metrics and exploratory-analysis approaches are illustrated. •Correlation and distance-based measures are overviewed. •Similarity analyses illustrated by several case studies. -- Abstract: Herbal medicines are becoming again more popular in the developed countries because being “natural” and people thus often assume that they are inherently safe. Herbs have also been used worldwide for many centuries in the traditional medicines. The concern of their safety and efficacy has grown since increasing western interest. Herbal materials and their extracts are very complex, often including hundreds of compounds. A thorough understanding of their chemical composition is essential for conducting a safety risk assessment. However, herbal material can show considerable variability. The chemical constituents and their amounts in a herb can be different, due to growing conditions, such as climate and soil, the drying process, the harvest season, etc. Among the analytical methods, chromatographic fingerprinting has been recommended as a potential and reliable methodology for the identification and quality control of herbal medicines. Identification is needed to avoid fraud and adulteration. Currently, analyzing chromatographic herbal fingerprint data sets has become one of the most applied tools in quality assessment of herbal materials. Mostly, the entire chromatographic profiles are used to identify or to evaluate the quality of the herbs investigated. Occasionally only a limited number of compounds are considered. One approach to the safety risk assessment is to determine whether the herbal material is substantially equivalent to that which is either readily consumed in the diet, has a history of application or has earlier been commercialized i.e. to what is considered as reference material. In order

2. Validação em métodos cromatográficos e eletroforéticos Validation for chromatographic and electrophoretic methods

Directory of Open Access Journals (Sweden)

Marcelo Ribani

2004-10-01

Full Text Available The validation of an analytical method is fundamental to implementing a quality control system in any analytical laboratory. As the separation techniques, GC, HPLC and CE, are often the principal tools used in such determinations, procedure validation is a necessity. The objective of this review is to describe the main aspects of validation in chromatographic and electrophoretic analysis, showing, in a general way, the similarities and differences between the guidelines established by the different Brazilian and international regulatory agencies.

3. Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

Energy Technology Data Exchange (ETDEWEB)

Fan Xiaohui [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Cheng Yiyu [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China)]. E-mail: chengyy@zju.edu.cn; Ye Zhengliang [Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310027 (China); Lin Ruichao [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China); Qian Zhongzhi [Committee of Chinese Pharmacopoeia, Beijing 100061 (China)

2006-01-12

Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines.

4. Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

International Nuclear Information System (INIS)

Fan Xiaohui; Cheng Yiyu; Ye Zhengliang; Lin Ruichao; Qian Zhongzhi

2006-01-01

Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of 'Danshen Dropping Pill' (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines

5. Validation of a fast and accurate chromatographic method for detailed quantification of vitamin E in green leafy vegetables.

Science.gov (United States)

Cruz, Rebeca; Casal, Susana

2013-11-15

Vitamin E analysis in green vegetables is performed by an array of different methods, making it difficult to compare published data or choosing the adequate one for a particular sample. Aiming to achieve a consistent method with wide applicability, the current study reports the development and validation of a fast micro-method for quantification of vitamin E in green leafy vegetables. The methodology uses solid-liquid extraction based on the Folch method, with tocol as internal standard, and normal-phase HPLC with fluorescence detection. A large linear working range was confirmed, being highly reproducible, with inter-day precisions below 5% (RSD). Method sensitivity was established (below 0.02 μg/g fresh weight), and accuracy was assessed by recovery tests (>96%). The method was tested in different green leafy vegetables, evidencing diverse tocochromanol profiles, with variable ratios and amounts of α- and γ-tocopherol, and other minor compounds. The methodology is adequate for routine analyses, with a reduced chromatographic run (<7 min) and organic solvent consumption, and requires only standard chromatographic equipment available in most laboratories. Copyright © 2013 Elsevier Ltd. All rights reserved.

6. Molecular Weights of Bovine and Porcine Heparin Samples: Comparison of Chromatographic Methods and Results of a Collaborative Survey.

Science.gov (United States)

Bertini, Sabrina; Risi, Giulia; Guerrini, Marco; Carrick, Kevin; Szajek, Anita Y; Mulloy, Barbara

2017-07-19

In a collaborative study involving six laboratories in the USA, Europe, and India the molecular weight distributions of a panel of heparin sodium samples were determined, in order to compare heparin sodium of bovine intestinal origin with that of bovine lung and porcine intestinal origin. Porcine samples met the current criteria as laid out in the USP Heparin Sodium monograph. Bovine lung heparin samples had consistently lower average molecular weights. Bovine intestinal heparin was variable in molecular weight; some samples fell below the USP limits, some fell within these limits and others fell above the upper limits. These data will inform the establishment of pharmacopeial acceptance criteria for heparin sodium derived from bovine intestinal mucosa. The method for MW determination as described in the USP monograph uses a single, broad standard calibrant to characterize the chromatographic profile of heparin sodium on high-resolution silica-based GPC columns. These columns may be short-lived in some laboratories. Using the panel of samples described above, methods based on the use of robust polymer-based columns have been developed. In addition to the use of the USP's broad standard calibrant for heparin sodium with these columns, a set of conditions have been devised that allow light-scattering detected molecular weight characterization of heparin sodium, giving results that agree well with the monograph method. These findings may facilitate the validation of variant chromatographic methods with some practical advantages over the USP monograph method.

7. Molecular Weights of Bovine and Porcine Heparin Samples: Comparison of Chromatographic Methods and Results of a Collaborative Survey

Directory of Open Access Journals (Sweden)

Sabrina Bertini

2017-07-01

Full Text Available In a collaborative study involving six laboratories in the USA, Europe, and India the molecular weight distributions of a panel of heparin sodium samples were determined, in order to compare heparin sodium of bovine intestinal origin with that of bovine lung and porcine intestinal origin. Porcine samples met the current criteria as laid out in the USP Heparin Sodium monograph. Bovine lung heparin samples had consistently lower average molecular weights. Bovine intestinal heparin was variable in molecular weight; some samples fell below the USP limits, some fell within these limits and others fell above the upper limits. These data will inform the establishment of pharmacopeial acceptance criteria for heparin sodium derived from bovine intestinal mucosa. The method for MW determination as described in the USP monograph uses a single, broad standard calibrant to characterize the chromatographic profile of heparin sodium on high-resolution silica-based GPC columns. These columns may be short-lived in some laboratories. Using the panel of samples described above, methods based on the use of robust polymer-based columns have been developed. In addition to the use of the USP’s broad standard calibrant for heparin sodium with these columns, a set of conditions have been devised that allow light-scattering detected molecular weight characterization of heparin sodium, giving results that agree well with the monograph method. These findings may facilitate the validation of variant chromatographic methods with some practical advantages over the USP monograph method.

8. High-performance liquid chromatographic method for guanylhydrazone compounds.

Science.gov (United States)

Cerami, C; Zhang, X; Ulrich, P; Bianchi, M; Tracey, K J; Berger, B J

1996-01-12

A high-performance liquid chromatographic method has been developed for a series of aromatic guanylhydrazones that have demonstrated therapeutic potential as anti-inflammatory agents. The compounds were separated using octadecyl or diisopropyloctyl reversed-phase columns, with an acetonitrile gradient in water containing heptane sulfonate, tetramethylammonium chloride, and phosphoric acid. The method was used to reliably quantify levels of analyte as low as 785 ng/ml, and the detector response was linear to at least 50 micrograms/ml using a 100 microliters injection volume. The assay system was used to determine the basic pharmacokinetics of a lead compound, CNI-1493, from serum concentrations following a single intravenous injection in rats.

9. Application of monolithic chromatographic supports in virus research.

Science.gov (United States)

Krajacic, Mladen; Ravnikar, Maja; Štrancar, Aleš; Gutiérrez-Aguirre, Ion

2017-11-01

Key properties of monolithic chromatographic supports, make them suitable for separation and/or concentration of large biomolecules, especially virus particles and viral genomes. One by one, the studies that have been completed so far, contributed to the knowledge that monolith chromatography has hardly any limitation to be applied in virus research. Viruses of different sizes, possessing icosahedral structure and symmetrical morphology, as well as rod-shaped or filamentous viruses with helical structure, even enveloped ones, all of them could be successfully managed by means of monolith chromatography. Same is true for viral genomes, primarily when being distinct from other nucleic acid forms present in a host cell. This review is exclusively focused on viruses. It describes the application of monolith chromatography to different problematics within the virus research field. The reviewed achievements offer new possibilities and trigger new aspects in virology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

10. Liquid chromatographic determination of tetracycline residues in animal feeds.

Science.gov (United States)

Martinez, E E; Shimoda, W

1988-01-01

A liquid chromatographic method for the multiresidue determination of tetracyclines (TCs) in feeds is described. The levels of quantitation were 10 ppm each for tetracycline-HCl (TC), oxytetracycline (OTC), and chlortetracycline-HCl (CTC); the detection limit was 40 ppb for each. The calibration curves were linear between 2.5 and 100 ppm. The procedure involved double extraction with pH 2.0 and pH 4.5 McIlvain buffers, cleanup on a Sephadex LH-20 column, separation on a Nova-Pak C18 column, and detection at 370 nm. Recoveries of 10 micrograms/g of each TC in multiresidue feed samples ranged from 55.8 to 75.5% for OTC, 71.6 to 100% for TC, and 22.4 to 60.6% for CTC. The identities of the TCs were confirmed by thin layer chromatography.

11. Automated chromatographic laccase-mediator-system activity assay.

Science.gov (United States)

Anders, Nico; Schelden, Maximilian; Roth, Simon; Spiess, Antje C

2017-08-01

To study the interaction of laccases, mediators, and substrates in laccase-mediator systems (LMS), an on-line measurement was developed using high performance anion exchange chromatography equipped with a CarboPac™ PA 100 column coupled to pulsed amperometric detection (HPAEC-PAD). The developed method was optimized for overall chromatographic run time (45 to 120 min) and automated sample drawing. As an example, the Trametes versicolor laccase induced oxidation of 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-dihydroxypropane (adlerol) using 1-hydroxybenzotriazole (HBT) as mediator was measured and analyzed on-line. Since the Au electrode of the PAD detects only hydroxyl group containing substances with a limit of detection being in the milligram/liter range, not all products are measureable. Therefore, this method was applied for the quantification of adlerol, and-based on adlerol conversion-for the quantification of the LMS activity at a specific T. versicolor laccase/HBT ratio. The automated chromatographic activity assay allowed for a defined reaction start of all laccase-mediator-system reactions mixtures, and the LMS reaction progress was automatically monitored for 48 h. The automatization enabled an integrated monitoring overnight and over-weekend and minimized all manual errors such as pipetting of solutions accordingly. The activity of the LMS based on adlerol consumption was determined to 0.47 U/mg protein for a laccase/mediator ratio of 1.75 U laccase/g HBT. In the future, the automated method will allow for a fast screening of combinations of laccases, mediators, and substrates which are efficient for lignin modification. In particular, it allows for a fast and easy quantification of the oxidizing activity of an LMS on a lignin-related substrate which is not covered by typical colorimetric laccase assays. ᅟ.

12. Study PWA8 resin for chromatographic uranium concentration

International Nuclear Information System (INIS)

Coceancigh, Herman; Ramella, J. L.; Marrero, Julieta; Jiménez Rebagliati, Raúl

2013-01-01

For many years nuclear industry have been using resins as filler of chromatographic columns. These methods are specific and give reliable results in different applications, for those reasons are extremely useful as separation process. Currently the nuclear industry is growing and this brings new issues such as the need of reduction of the amount of waste, the optimization of the production process and others that the chromatography could solve with great results. AMBERLITETM PWA8 resin is an anion exchange resin which can be used for the removal of uranium from drinking water. In addition to high exchange capacity, this resin has excellent physical stability and a wide range of pH in which is operational. With the idea of concentrating uranium from wastes solution as main goal we made different experiments to understand the AMBERLITETM PWA8 and obtain the most important characteristics like; pH working range; capacity; activation and elution procedures. These procedures were developed and optimized the capacity was determined using a batch experiment and we obtain that the maximum capacity is 882,5 U ug /resin gr at a pH of 4,2. Following on from these results chromatographic experiments were performed in which both were obtained the percentage of recovery and the concentration factor. The percent recovery (% R) calculated as the percentage ratio between the total mass and the load mass eluted (% R = eluted mass / total mass * 100) was 94% with a concentration factor of 5 times From these results it is intended to concentrate wastes solutions from the fuel cycle processes with two main goals: decreasing volume for storage and for future reusing of the uranium coming from production. (author)

13. Chromatographic profiles of extractives from leaves of Eugenia uniflora

Directory of Open Access Journals (Sweden)

Isabelle C.F. Bezerra

Full Text Available ABSTRACT Eugenia uniflora L., Myrtaceae, popularly known as “pitanga”, is used in traditional medicine due the properties attributed to its chemical content, these being mainly hydrolysable tannins and flavonoids. This study provides a qualitative and quantitative evaluation of chemical profile from leaves of E. uniflora. The HPLC analysis was carried out on a C18 column (4.6 mm × 250 mm, 5 µm by gradient elution with methanol and water (acidified with trifluoracetic acid; and silica gel Plates 60-F 254 with 10–12 µm and 5–6 µm particles, respectively for TLC and High HPTLC analysis. The chromatographic data obtained from HPLC, TLC and HPTLC presented bands and peaks related to flavonoids (myricitrin and derivatives and tannins (gallic and ellagic acids, which were observed from different samples. The chromatographic similarities enabled the building of a typical fingerprint for the herbal material. The similarity analysis of the sample data by Pearson correlation showed R values >0.9 among peaks (HPLC and bands (HPTLC. In addition, the analytical methodology developed by HPLC enabled the satisfactory quantification of marker substances [ellagic acid = 0.22% and 0.20% (m/m; gallic acid = 0.20% and 0.43%; myricitrin = 0.42 and 1.74% (m/m in herbal drug and crude extract, respectively]. The procedure was also validated in accordance with the assays required by Brazilian legislation. Thus, the HPTLC and HPLC methods developed in this study provide helpful and simple tools for the quality evaluation both qualitatively and quantitatively of raw materials and extractives from leaves of E. uniflora.

14. A gas/liquid chromatographic-mass spectrometric method for the rapid screening of 250 pesticides in aqueous matrices

Energy Technology Data Exchange (ETDEWEB)

Chandramouli, B.; Harvan, D.; Brittain, S.; Hass, R. [Eno River Labs, LLC. Durham, NC (United States)

2004-09-15

Pesticide residues in food present a potentially serious and significant cause for concern. Many pesticides have been associated with significant health effects to the nervous and endocrine systems and some have been deemed carcinogenic. There are many well-established techniques for pesticide analysis. However, commercial pesticide methods have traditionally only been available for specific pesticide families, such as chlorinated pesticides or herbicides, and at detection limits ranging from 0.05 ppb to 1 ppm in aqueous matrices. Techniques that can quickly screen for the presence/absence of pesticide residues in food matrices are critical in ensuring the safety of food and water. This paper outlines a combined Gas Chromatographic-High Resolution Mass Spectrometric (GC-HRMS) and Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) screening assay for 250 pesticides that was developed for use in water, and soda samples at screening levels ranging from 0.1-5 ppb. The pesticides selected have been identified by the European Union as being of concern and the target of possible legislation. The list encompasses a variety of pesticide classes and compound groupings.

15. A review of chromatographic methods for the determination of water- and fat-soluble vitamins in biological fluids.

Science.gov (United States)

2016-01-01

Vitamins are an essential element of nutrition and thus contribute to human health. Vitamins catalyze many biochemical reactions and their lack or excess can cause health problems. Therefore, monitoring vitamin concentrations in plasma or other biological fluids may be useful in the diagnosis of various disorders as well as in the treatment process. Several chromatographic methods have been developed for the determination of these compounds in biological samples, including high-performance liquid chromatography with UV and fluorescence detection. Recently, high-performance liquid chromatography with tandem mass spectrometry methods have been widely used for the determination of vitamins in complex matrices because of their high sensitivity and selectivity. This method requires preconditioning of samples for analysis, including protein precipitation and/or various extraction techniques. The choice of method may depend on the desired cost, convenience, turnaround time, specificity, and accuracy of the information to be obtained. This article reviews the recently reported chromatographic methods used for determination of vitamins in biological fluids. Relevant papers published mostly during the last 5 years were identified by an extensive PubMed search using appropriate keywords. Particular attention was given to the preparation steps and extraction techniques. This report may be helpful in the selection of procedures that are appropriate for certain types of biological materials and analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

16. Review of UV spectroscopic, chromatographic, and electrophoretic methods for the cholinesterase reactivating antidote pralidoxime (2-PAM).

Science.gov (United States)

John, Harald; Blum, Marc-Michael

2012-01-01

Pralidoxime (2-PAM) belongs to the class of monopyridinium oximes with reactivating potency on cholinesterases inhibited by phosphylating organophosphorus compounds (OPC), for example, pesticides and nerve agents. 2-PAM represents an established antidote for the therapy of anticholinesterase poisoning since the late 1950s. Quite high therapeutic concentrations in human plasma (about 13 µg/ml) lead to concentrations in urine being about 100 times higher allowing the use of less sensitive analytical techniques that were used especially in the early years after 2-PAM was introduced. In this time (mid-1950s until the end of the 1970s) 2-PAM was most often analyzed by either paper chromatography or simple UV spectroscopic techniques omitting any sample separation step. These methods were displaced completely after the establishment of column liquid chromatography in the early 1980s. Since then, diverse techniques including cation exchange, size-exclusion, reversed-phase, and ligand-exchange chromatography have been introduced. Today, the most popular method for 2-PAM quantification is ion pair chromatography often combined with UV detection representing more than 50% of all column chromatographic procedures published. Furthermore, electrophoretic approaches by paper and capillary zone electrophoresis have been successfully used but are seldom applied. This review provides a commentary and exhaustive summary of analytical techniques applied to detect 2-PAM in pharmaceutical formulations and biological samples to characterize stability and pharmacokinetics as well as decomposition and biotransformation products. Separation techniques as well as diverse detectors are discussed in appropriate detail allowing comparison of individual preferences and limitations. In addition, novel data on mass spectrometric fragmentation of 2-PAM are provided. Copyright © 2011 John Wiley & Sons, Ltd.

17. Ion Chromatographic Method with Post-Column Fuchsin Reaction for Measurement of Bromate in Chlorinated Water

Directory of Open Access Journals (Sweden)

Homer C. Genuino

2009-06-01

Full Text Available An ion chromatographic method that employs a post-column reaction with fuchsin and spectrophotometric detection was optimized for measuring bromate (BrO3- in water. BrO3- is converted to Br2 by sodium metabisulfite and then reacted with acidic fuchsin to form a red-colored product that strongly absorbs at 530 nm. The reaction of BrO3- and fuchsin reagent is optimum at pH 3.5 and 65 oC. The method has a limit of quantitation of 4.5 µg L-1 and is linear up to 150 µg L-1 BrO3-. Recoveries from spiked samples were high ranging from 95 to 102 % using external standard calibration and 87 to 103 % using standard addition method. Intra-batch and inter-batch reproducibility studies of the method resulted to RSD values ranging from 0.62 to 2.01 % and percent relative error of 0.12 to 2.94 % for BrO3- concentrations of 10 µg L-1 and 50 µg L-1. This method is free of interferences from common inorganic anions at levels typically found in chlorinated tap drinking water without preconcentration. The optimized method can be applied to trace analysis of bromate in chlorinated tap drinking water samples.

18. Validation of high performance liquid chromatographic and spectrophotometric methods for the determination of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products

Directory of Open Access Journals (Sweden)

Serpil Sevim

2015-12-01

Full Text Available abstract The antiparkinson agent pramipexole dihydrochloride monohydrate was quantified in pharmaceutical products by high performance liquid chromatography (HPLC and derivative spectrophotometry. The first method was based on HPLC using tamsulosin HCl as an internal standard. In this method, chromatographic separation was achieved using a LiChrospher 60 RP column at 25°C, with a flow rate of 1.0 mL/min at 263 nm. The eluent comprised 0.01 mol/L ammonium acetate (pH 4.4 and acetonitrile (35:65 by volume. The linearity range was found to be 10.0-30.0 µg/mL with a mean recovery of 100.5 ± 1.10. The limit of detection (8 ng/mL and limit of quantification (50 ng/mL were calculated. In the second method, the first derivative spectrophotometric technique for the determination of pramipexole dihydrochloride monohydrate was performed by measuring the amplitude at 249 and 280 nm. In the first derivative technique, the absorbance and concentration plot was rectilinear over the 5.0-35.0 µg/mL range with a lower detection limit of 1.5 ng/mL and quantification limit of 4.5 ng/mL. The typical excipients included in the pharmaceutical product do not interfere with the selectivity of either method. The developed methods were validated for robustness, selectivity, specificity, linearity, precision, and accuracy as per the ICH and FDA guidelines (ICH Q2B, 1996; FDA,2000. In conclusion, the developed methods were successful in determining the quantity of the antiparkinson agent pramipexole dihydrochloride monohydrate in pharmaceutical products. The RSD values for the pharmaceutical product used in this study were found to be 0.97% for the HPLC method and 0.00% for the first derivative spectrophotometric method.

19. Parameter selection for peak alignment in chromatographic sample profiling: Objective quality indicators and use of control samples

NARCIS (Netherlands)

Peters, S.; van Velzen, E.; Janssen, H.-G.

2009-01-01

In chromatographic profiling applications, peak alignment is often essential as most chromatographic systems exhibit small peak shifts over time. When using currently available alignment algorithms, there are several parameters that determine the outcome of the alignment process. Selecting the

20. Frequency standards

CERN Document Server

Riehle, Fritz

2006-01-01

Of all measurement units, frequency is the one that may be determined with the highest degree of accuracy. It equally allows precise measurements of other physical and technical quantities, whenever they can be measured in terms of frequency.This volume covers the central methods and techniques relevant for frequency standards developed in physics, electronics, quantum electronics, and statistics. After a review of the basic principles, the book looks at the realisation of commonly used components. It then continues with the description and characterisation of important frequency standards

1. Chromatographic separations for fission products and actinides determination by different analytical techniques: mass spectrometry and radiometry

OpenAIRE

Perna, Lorenzo

2003-01-01

Due to the nuclear testing, reentry and disintegration of nuclear powered satellites, nuclear reactor accidents, uranium nuclear fuel cycle and nuclear weapons production, actinides have been introduced into the environment. Proposed disposal of high-level radioactive waste in mined repositories in geologic formation as well as the storage and disposal of uranium and plutonium from weapons dismantlement are further possible sources for actinide releases to the environment. The mobilization of...

2. Differentiation of degrees of ripeness of Catuai and Tipica green coffee by chromatographical and statistical techniques.

Science.gov (United States)

Smrke, Samo; Kroslakova, Ivana; Gloess, Alexia N; Yeretzian, Chahan

2015-05-01

The quality of green coffee is influenced by the degree of ripeness of the fruit at harvest. The aim of this study was to identify chemical markers differentiating between degrees of ripeness. Two coffee varieties, Catuai and Tipica, from the same farm were analysed using the following parameters and methods: caffeine and chlorogenic acid content using high-performance liquid chromatography (HPLC), sucrose content using hydrophilic interaction chromatography, high-molecular weight fraction (HMW) using high-performance size-exclusion chromatography (HPSEC) and volatile compounds using headspace solid phase micro extraction gas chromatography/mass spectrometry. The best method for differentiating between degrees of ripeness was found to be principal component analysis (PCA) based on HPLC data. HPSEC showed differences in the HMW fraction for different degrees of ripeness and both coffee varieties. Volatile profiles allowed separation of both varieties; yet, except for ripe Catuai, no separation was achieved for the degree of ripeness. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

3. An analysis of avidin, biotin and their interaction at attomole levels by voltammetric and chromatographic techniques

Czech Academy of Sciences Publication Activity Database

Kizek, René; Masařík, Michal; Kramer, Karl J.; Potěšil, David; Bailey, M.; Howard, John A.; Klejdus, Bořivoj; Mikelová, Radka; Adam, V.; Trnková, Libuše; Jelen, František

2005-01-01

Roč. 381, č. 6 (2005), s. 1167-1178 ISSN 1618-2642 R&D Projects: GA ČR(CZ) GP525/04/P132; GA ČR(CZ) GA203/02/0422; GA MŠk(CZ) LN00A081; GA AV ČR(CZ) IAA1163201 Institutional research plan: CEZ:AV0Z50040507 Keywords : avidin * biotin * avidin- biotin technology Subject RIV: BO - Biophysics Impact factor: 2.695, year: 2005

4. Binding of low molecular mass compounds to proteins studied by liquid chromatographic techniques

Czech Academy of Sciences Publication Activity Database

Cserháti, T.; Forgács, E.; Deyl, Zdeněk; Mikšík, Ivan; Eckhardt, Adam

2003-01-01

Roč. 17, č. 6 (2003), s. 353-360 ISSN 0269-3879 Institutional research plan: CEZ:AV0Z5011922 Keywords : protein binding Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.269, year: 2003

5. POTENTIAL AND PITFALLS OF CHROMATOGRAPHIC TECHNIQUES AND DETECTION MODES IN SUBSTANCE IDENTIFICATION FOR SYSTEMATIC TOXICOLOGICAL ANALYSIS

NARCIS (Netherlands)

DEZEEUW, RA; HARTSTRA, J; FRANKE, JP

1994-01-01

The potential and the constraints of thin-layer chromatography (TLC), gas chromatography (GC) and high-performance liquid chromatography (HPLC) towards substance identification, together with their detection modes, are considered. The latter include colour reactions on the plate, molecular masses

6. Multivariate curve resolution of incomplete fused multiset data from chromatographic and spectrophotometric analyses for drug photostability studies.

Science.gov (United States)

De Luca, Michele; Ragno, Gaetano; Ioele, Giuseppina; Tauler, Romà

2014-07-21

An advanced and powerful chemometric approach is proposed for the analysis of incomplete multiset data obtained by fusion of hyphenated liquid chromatographic DAD/MS data with UV spectrophotometric data from acid-base titration and kinetic degradation experiments. Column- and row-wise augmented data blocks were combined and simultaneously processed by means of a new version of the multivariate curve resolution-alternating least squares (MCR-ALS) technique, including the simultaneous analysis of incomplete multiset data from different instrumental techniques. The proposed procedure was applied to the detailed study of the kinetic photodegradation process of the amiloride (AML) drug. All chemical species involved in the degradation and equilibrium reactions were resolved and the pH dependent kinetic pathway described. Copyright © 2014 Elsevier B.V. All rights reserved.

7. Thin-layer chromatographic separation and determination of dibutylphosphoric acid in a mixture of monobutylphosphoric acid and tributyl phosphate

International Nuclear Information System (INIS)

1986-01-01

A thin-layer chromatographic (TLC) technique using a silica gel-cellulose plate has been developed for the separation of a mixture of monobutylphosphoric acid (H 2 MBP), dibutylphosphoric acid (HDBP) and tributyl phosphate (TBP) and for the determination of HDBP. The technique involves initial separation on a TLC plate followed by the determination of isolated HDBP by an indirect spectrophotometric method whereby the concentration of HDBP is measured by its ability to reduce the colour intensity of a thorium-thoron complex at 545 nm. Less than 1 μg of H 2 MBP and HDBP can be detected on the TLC plate. The method is suitable for the determination of 40 to 260 μg of HDBP. (author)

8. Manual of Standard Operating Procedures for Veterinary Drug Residue Analysis

International Nuclear Information System (INIS)

2016-01-01

Laboratories are crucial to national veterinary drug residue monitoring programmes. However, one of the main challenges laboratories encounter is obtaining access to relevant methods of analysis. Thus, in addition to training, providing technical advice and transferring technology, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has resolved to develop clear and practical manuals to support Member State laboratories. The Coordinated Research Project (CRP) on Development of Radiometric and Allied Analytical Methods to Strengthen Residue Control Programs for Antibiotic and Anthelmintic Veterinary Drug Residues has developed a number of analytical methods as standard operating procedures (SOPs), which are now compiled here. This publication contains SOPs on chromatographic and spectrometric techniques, as well as radioimmunoassay and associated screening techniques, for various anthelmintic and antimicrobial veterinary drug residue analysis. Some analytical method validation protocols are also included. The publication is primarily aimed at food and environmental safety laboratories involved in testing veterinary drug residues, including under organized national residue monitoring programmes. It is expected to enhance laboratory capacity building and competence through the use of radiometric and complementary tools and techniques. The publication is also relevant for applied research on residues of veterinary drugs in food and environmental samples

9. Is There a Cosmetic Advantage to Single-Incision Laparoscopic Surgical Techniques Over Standard Laparoscopic Surgery? A Systematic Review and Meta-analysis.

Science.gov (United States)

Evans, Luke; Manley, Kate

2016-06-01

Single-incision laparoscopic surgery represents an evolution of minimally invasive techniques, but has been a controversial development. A cosmetic advantage is stated by many authors, but has not been found to be universally present or even of considerable importance by patients. This systematic review and meta-analysis demonstrates that there is a cosmetic advantage of the technique regardless of the operation type. The treatment effect in terms of cosmetic improvement is of the order of 0.63.

10. [Standardizing the manipulation procedure of acupuncture-moxibustion, reinforcing the training of' clinical skill: learning experience of Acupuncture-moxibustion Clinical Skills Training: Chapter of Commonly Used Needling and Moxibustion Techniques].

Science.gov (United States)

Tian, Hongfang; Yang, Chao; Tang, Jie; Qin, Qiuguo; Zhao, Mingwen; Zhao, Jiping

2015-07-01

The book Acupuncture-moxibustion Clinical Skills Training is one of "Twelfth Five-Year Plan" in novative teaching materials, which is published by People's Medical Publishing House. Through learning the first half of the book commonly used needling and moxibustion techniques, it is realized that the selection of book content is reasonable and much attention is paid to needling and moxibustion techniques; the chapter arrangement is well-organized, and the form is novel, which is concise and intuitive; for every technique, great attention is paid to standardize the manipulation procedure and clarify the technique key, simultaneously the safety of acupuncture and moxibustion is also emphasized. The characteristics of the book, including innovativeness, practicability, are highlighted, and it greatly helps to improve students' clinical skills and examination ability.

11. High gas temperature furnace for species determination of organometallic compounds with a high pressure liquid chromatograph and a Zeeman atomic absorption spectrometer

Energy Technology Data Exchange (ETDEWEB)

Koizumi, H.; McLaughlin, R.D.; Hadeishi, T.

1979-03-01

A new furnace has been constructed that allows atomic absorption detection of volatile organometallic compounds. The operation of this furnace is demonstrated by analyzing the eluent of a high pressure liquid chromatograph utilizing Zeeman atomic absorption spectrometry. The content of tetraethyllead in National Bureau of Standards gasoline standards was determined. Data are presented on the ability of this furnace to suppress interference with cadmium and lead determinations by MgCl/sub 2/, CuCl/sub 2/, and CaCl/sub 2/. It was found that two orders of magnitude more interferent can be tolerated. The determination of lead in automotive exhaust is also described. 7 figures, 4 tables.

12. Standards for holdup measurement

International Nuclear Information System (INIS)

Zucker, M.S.

1982-01-01

Holdup measurement, needed for material balance, depend intensively on standards and on interpretation of the calibration procedure. More than other measurements, the calibration procedure using the standard becomes part of the standard. Standards practical for field use and calibration techniques have been developed. While accuracy in holdup measurements is comparatively poor, avoidance of bias is a necessary goal

13. Use of coextraction and suppression of extraction in extraction-chromatographic separation of elements

International Nuclear Information System (INIS)

Karandashev, V.K.; Kuznetsov, R.A.; Grazhulene, S.S.; Usmanova, M.M.

1988-01-01

TBP, solutions of hydrobromic acid, indium and polytetrafluoroethylene powder, carrier for TBP, were used to study the effects of coextraction and extraction suppression on extraction-chromatographic behaviour of microamounts of elements in the presence of macroamounts of other elements. Possibility of using these effects under extraction-chromatographic element separation were considered. A new method for extraction-chromatographic separation of scandium microamounts from the mixture of large amount of elements (Y, Cd, Ce, Eu, Lu, Hf, Ta, W, Np and other) was suggested. 15 refs.; 3 figs

14. A high performance liquid chromatographic assay of mefloquine in saliva after a single oral dose in healthy adult Africans.

Science.gov (United States)

Gbotosho, Grace O; Happi, Christian T; Lawal, Omowunmi; Sijuade, Abayomi; Sowunmi, Akin; Oduola, Ayoade

2012-02-27

Mefloquine-artesunate is a formulation of artemisinin based combination therapy (ACT) recommended by the World Health Organization and historically the first ACT used clinically. The use of ACT demands constant monitoring of therapeutic efficacies and drug levels, in order to ensure that optimum drug exposure is achieved and detect reduced susceptibility to these drugs. Quantification of anti-malarial drugs in biological fluids other than blood would provide a more readily applicable method of therapeutic drug monitoring in developing endemic countries. Efforts in this study were devoted to the development of a simple, field applicable, non-invasive method for assay of mefloquine in saliva. A high performance liquid chromatographic method with UV detection at 220 nm for assaying mefloquine in saliva was developed and validated by comparing mefloquine concentrations in saliva and plasma samples from four healthy volunteers who received single oral dose of mefloquine. Verapamil was used as internal standard. Chromatographic separation was achieved using a Hypersil ODS column. Extraction recoveries of mefloquine in plasma or saliva were 76-86% or 83-93% respectively. Limit of quantification of mefloquine was 20 ng/ml. Agreement between salivary and plasma mefloquine concentrations was satisfactory (r = 0.88, p mefloquine in saliva paralleled that in plasma, making salivary quantification of mefloquine potentially useful in therapeutic drug monitoring. © 2012 Gbotosho et al; licensee BioMed Central Ltd.

15. A high performance liquid chromatographic assay of Mefloquine in saliva after a single oral dose in healthy adult Africans

Directory of Open Access Journals (Sweden)

Gbotosho Grace O

2012-02-01

Full Text Available Abstract Background Mefloquine-artesunate is a formulation of artemisinin based combination therapy (ACT recommended by the World Health Organization and historically the first ACT used clinically. The use of ACT demands constant monitoring of therapeutic efficacies and drug levels, in order to ensure that optimum drug exposure is achieved and detect reduced susceptibility to these drugs. Quantification of anti-malarial drugs in biological fluids other than blood would provide a more readily applicable method of therapeutic drug monitoring in developing endemic countries. Efforts in this study were devoted to the development of a simple, field applicable, non-invasive method for assay of mefloquine in saliva. Methods A high performance liquid chromatographic method with UV detection at 220 nm for assaying mefloquine in saliva was developed and validated by comparing mefloquine concentrations in saliva and plasma samples from four healthy volunteers who received single oral dose of mefloquine. Verapamil was used as internal standard. Chromatographic separation was achieved using a Hypersil ODS column. Results Extraction recoveries of mefloquine in plasma or saliva were 76-86% or 83-93% respectively. Limit of quantification of mefloquine was 20 ng/ml. Agreement between salivary and plasma mefloquine concentrations was satisfactory (r = 0.88, p Conclusion Disposition of mefloquine in saliva paralleled that in plasma, making salivary quantification of mefloquine potentially useful in therapeutic drug monitoring.

16. Gas Chromatographic-Selected Ion Monitoring-Mass Spectrometric Determination of Cigarette Mainstream Smoke Components with Sensory Attributes

Directory of Open Access Journals (Sweden)

Coleman WM

2014-12-01

Full Text Available A new method has been developed that detects significant quantitative differences in the amounts of pyrazines, pyridines, furfurals, carboxylic acids, b-damascenone, sclareolide, and megastigmatrienones in the mainstream smoke of a series of five commercial cigarettes. This new quantitative method is based on the gas chromatographic-selected ion monitoring-mass spectrometric (GC-SIM-MS determination of the selected smoke constituents. The accuracy and precision of the approach were well within acceptable parameters with the majority of cases relative standard deviation (RSD values consistently around 5%. Sample preparation was simple requiring only the dissolution of the trapped particulate material in a known volume of methanol followed by injection of this clear dark colored solution into the gas chromatograph. This approach represents an advance in the technology in terms of higher sample throughput and less sample workup. Certain products demonstrated consistent trends in concentration of specific chemical classes. The mainstream smoke from a University of Kentucky reference cigarette, 2R4F, was included for reference purposes. These results are applicable in the overall evaluation of the components responsible for the taste associated with cigarette products.

17. Porous chromatographic materials as substrates for preparing synthetic nuclear explosion debris particles

International Nuclear Information System (INIS)

Harvey, S.D.; Carman, A.J.; Martin Liezers; Antolick, K.C.; Garcia, B.J.; Eiden, G.C.; Sweet, L.E.

2013-01-01

18. Thin-layer chromatographic plates with monolithic layer of silica: production, physical-chemical characteristics, separation capabilities.

Science.gov (United States)

Frolova, Anastasiya M; Konovalova, Olga Y; Loginova, Lidia P; Bulgakova, Alena V; Boichenko, Alexander P

2011-08-01

The technique for production of thin-layer chromatographic plates with fixed monolithic layer of sorbent was developed on the basis of investigation of factors affecting sorption capacity, sorption kinetics and mechanical stability of monoliths. The optimal reaction mixture for sol-gel synthesis of monoliths consisted of tetraethoxysilane, buffer solution with pH 7.4, N,N-dimethylformamide, ethanol, polyethyleneglycol with molecular weight 1000 and cetylpyridinium chloride in molar ratio 1.0:4.6:1.4:7.6:0.26:8×10(-3). On the basis of analysis of sorption kinetics of malachite green on the monoliths it was concluded that mechanism of sorption includes chemisorption. The optimized conditions for fixing the monolithic layer on the carrier and its drying allow obtaining undisturbed monolithic layer, which was used for test mixtures separation. The increase of monolithic layer thickness in comparison with ultrathin-layer chromatographic plates allows detecting visually at reasonable concentrations and loaded sample volumes the spots of food and synthetic dyes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

19. Preparation, chromatographic evaluation and biodistribution of {sup 99m}Tc-procainamide as a radiopharmaceutical for heart imaging

Energy Technology Data Exchange (ETDEWEB)

Motaleb, M.A.; Ibrahim, I.T.; Abo Rizq, R.S. [Atomic Energy Authority, Cairo (Egypt). Labeled Compound Dept.; Elzanfaly, E.S. [Cairo Univ. (Egypt). Analytical Dept.

2017-06-01

Procainamide (4-amino-N-[2-(diethylamino) ethyl] benzamide) is a sodium channel blocker, which acts as an effective antiarrhythmic agent used in the treatment of a variety of atrial and ventricular arrhythmias. The aim of this study was to prepare {sup 99m}Tc-procainamide complex, apply different chromatographic techniques for the assay of radiolabeling yield and study its biodistribution as a novel radiopharmaceutical for heart imaging. {sup 99m}Tc-procainamide was obtained with a maximum labeling yield of 95.76±0.20% via direct labeling method under optimum conditions of 200 μg of procainamide, 300 μL of buffer (carbonate) at pH 11, 30 μg SnCl{sub 2} . 2H{sub 2}O at room temperature (25 C) for 15 min. In terms of in vitro stability, the complex was stable for 3 h. Chromatographic evaluation using paper chromatography, thin layer chromatography, gel chromatography, and high performance liquid chromatography showed reliable results for measuring the radiochemical yield. Biodistribution study of {sup 99m}Tc-procainamide showed ratios of heart/lung and heart/liver (6.38±1.50, 2.06±0.31, respectively at 30 min post injection) which was comparable to that of {sup 99m}Tc-sestamibi (7.4±2.00, 0.97±0.10, respectively at 60 min, P<0.05).

20. Standard test method for determining the crevice repassivation potential of corrosion-resistant alloys using a potentiodynamic-galvanostatic-potentiostatic technique

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This test method covers a procedure for conducting anodic polarization studies to determine the crevice repassivation potential for corrosion–resistant alloys. The concept of the repassivation potential is similar to that of the protection potential given in Reference Test Method G 5. 1.2 The test method consists in applying successively potentiodynamic, galvanostatic, and potentiostatic treatments for the initial formation and afterward repassivation of crevice corrosion. 1.3 This test method is a complement to Test Method G 61. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1. Chemical Compositions, Chromatographic Fingerprints and Antioxidant Activities of Andrographis Herba

Directory of Open Access Journals (Sweden)

Yang Zhao

2014-11-01

Full Text Available This paper describes the development of an HPLC-UV-MS method for quantitative determination of andrographolide and dehydroandrographolide in Andrographis Herba and establishment of its chromatographic fingerprint. The method was validated for linearity, limit of detection and quantification, inter- and intra-day precisions, repeatability, stability and recovery. All the validation results of quantitative determination and fingerprinting methods were satisfactory. The developed method was then applied to assay the contents of andrographolide and dehydroandrographolide and to acquire the fingerprints of all the collected Andrographis Herba samples. Furthermore, similarity analysis and principal component analysis were used to reveal the similarities and differences between the samples on the basis of the characteristic peaks. More importantly, the DPPH free radical-scavenging and ferric reducing capacities of the Andrographis Herba samples were assayed. By bivariate correlation analysis, we found that six compounds are positively correlated to DPPH free radical scavenging and ferric reducing capacities, and four compounds are negatively correlated to DPPH free radical scavenging and ferric reducing capacities.

2. Recent Advances in Water Analysis with Gas Chromatograph Mass Spectrometers

Science.gov (United States)

2014-01-01

We report on progress made in developing a water sampling system for detection and analysis of volatile organic compounds in water with a gas chromatograph mass spectrometer (GCMS). Two approaches are described herein. The first approach uses a custom water pre-concentrator for performing trap and purge of VOCs from water. The second approach uses a custom micro-volume, split-splitless injector that is compatible with air and water. These water sampling systems will enable a single GC-based instrument to analyze air and water samples for VOC content. As reduced mass, volume, and power is crucial for long-duration, manned space-exploration, these water sampling systems will demonstrate the ability of a GCMS to monitor both air and water quality of the astronaut environment, thereby reducing the amount of required instrumentation for long duration habitation. Laboratory prototypes of these water sampling systems have been constructed and tested with a quadrupole ion trap mass spectrometer as well as a thermal conductivity detector. Presented herein are details of these water sampling system with preliminary test results.

3. Extraction chromatographic studies on a strontium selective crown ether

International Nuclear Information System (INIS)

Pathak, P.N.; Mohapatra, P.K.; Kulkarni, M.J.; Manchanda, V.K.

1998-08-01

Selective adsorption of radiostrontium from nitric acid medium on a chromatographic resin material consisting of di-t-butyl cyclohexano 18 crown 6/n-octanol sorbed onto amberlite XAD-7 (particle size: 100-150μm) has been carried out. The column capacity is evaluated as ∼ 21 mg of Sr per gram of the resin material. The separation of radiostrontium from several metal ions present in environmental and biological samples viz. Li, Na, K, Mg, Ca, Al, Fe, Co, Ni, Zn and Cd has been achieved. A promising separation method for 90 Y from 90 Sr- 90 Y mixture has also been developed. Nitric acid concentration has no observable effect on the elution profile of 90 Y as the entire amount of the loaded 90 Y activity can be eluted by 1.5 ml of the acid in a wide concentration range (0. 1 - 10 M). Half-life of the eluted 90 Y sample is calculated as 63.75 ± 0.40 hours by following the decay profile. Repeated elutions using 1.5 ml of 3 M HNO 3 after loading 200 μCi of 90 Sr - 90 Y revealed that the product with ∼ 98% radiochemical purity could be obtained up to the 12th run beyond which the contamination due to 90 Sr increased significantly. (author)

4. Brazilian organic sugarcane spirits: Physicochemical and chromatographic profile

Directory of Open Access Journals (Sweden)

Felipe Cimino Duarte

Full Text Available ABSTRACT There has been a growing demand for products from organic agriculture for the food market. Brazil leads the production of sugarcane spirits and produces about 1.6 billion liters/year. New technologies have been sought throughout the supply chain to improve production, and organic raw material has been used in the production of sugar cane for the production of beverages. This study aimed to define the physicochemical and chromatographic profiles of eleven organic sugarcane spirits samples from various Brazilian states. The secondary components and contaminants were identified and quantified through physicochemical analyses, HPLC and gas chromatography (GC. A significant percentage of the organic sugarcane spirits samples contained concentrations of components that were above the limits required by the Ministry of Agriculture, Livestock and Provisioning (MAPA, specifically the esters (18.20%, copper and dry extract (9.10%. This contamination is caused by bad conditions employed during the production process, which are not in compliance with the good manufacturing practices determined and legislated by Brazilian law.

5. High performance liquid chromatographic determination of mazindol in human plasma.

Science.gov (United States)

Kaddoumi, A; Mori, M; Nanashima, K; Kono, M; Nakashima, K

2001-11-01

A simple and convenient high performance liquid chromatographic method with UV detection is described for the determination of mazindol [5-(p-chlorophenyl)-2,5-dihydro-3H-imidazo[2,1-a]isoindol-5-ol] and its major metabolite, 2-(2-aminoethyl)-3-(p-chlorophenyl)-3-hydroxyphthalimidine (Met), in human plasma. The analytes were extracted with ethyl acetate from plasma samples and separated on a C18 column using acetonitrile-0.067 mol dm(-3) phosphate buffer (pH 3.5) (24 + 76 v/v) as a mobile phase. The eluates were monitored at 220 nm. Following complete validation and stability studies, the proposed method proved to be sensitive and precise. The limits of detection were 0.07 and 0.08 ng ml(-1) of plasma for mazindol and Met, respectively. The accuracy and recovery were in the ranges 94-102% and 91-102%, respectively, for both compounds. The intra- and inter-assay precisions were less than 7.6 and 9.2%, respectively, for both compounds. The stability of mazindol under different storage conditions, i.e., at room temperature (rt) and 4 degrees C and with freeze-thaw cycles, was also examined. Mazindol was unstable in plasma samples left at rt and 4 degrees C. The method was applied to the determination of mazindol and Met in the plasma of a patient treated for obesity with mazindol.

6. Improving the binding capacities of protein A chromatographic materials by means of ligand polymerization.

Science.gov (United States)

Freiherr von Roman, Matthias; Berensmeier, Sonja

2014-06-20

Protein A chromatography is one of the most important techniques used in the purification of monoclonal antibodies. Due to the low dynamic binding capacity of protein A chromatographic materials compared to other stationary phases, protein A chromatography is often discussed to be the bottleneck among current purification processes. Several approaches were tested within this study in order to maximize IgG binding capacities of current acrylamido-based based resins. Genetic engineering techniques were used in order to polymerize one of the IgG binding domains (B-domain) of protein A from Staphylococcus aureus (SpA) to achieve ligands with an increased length. The solution-binding ratio and the total size of ligand-antibody complexes were used to characterize the interaction potential of novel ligands, revealing a relatively linear dependency between the number of binding domains upon the amount of bound antibody molecules. This relationship was also valid up to a ligand which was comprised of 8 B-domains after attaching them onto acrylamido-based based stationary phases using epoxy coupling techniques. Equilibrium binding capacities of more than 80mghIgGmL(-1) were achieved using the B8 ligand. Furthermore, static binding capacities, especially for smaller ligands comprised of fewer B-domains, were improved up to 87mghIgGmL(-1) using site-specific coupling chemistry, which is an improvement of more than 20% compared to commercially available materials. In order to evaluate pore exclusion effects due to the use of prolonged affinity ligands, prepared materials were characterized regarding their effective intraparticle porosity and breakthrough capacity. Copyright © 2014 Elsevier B.V. All rights reserved.

7. Chromatographic analyses of fatty acid methyl esters by HPLC-UV and GC-FID

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Myller S.; Pinho, David M.M.; Suarez, Paulo A.Z., E-mail: psuarez@unb.br [Laboratorio de Materiais e Combustiveis, Instituto de Quimica, Universidade de Brasilia, DF (Brazil); Mendonca, Marcio A. [Faculdade de Agronomia e Medicina Veterinaria, Universidade de Brasilia, DF (Brazil); Resck, Ines S. [Laboratorio de Ressonancia Magnetica Nuclear, Universidade de Brasilia, DF (Brazil)

2012-04-15

An analytical method using high performance liquid chromatography with UV detection (HPLC-UV) (method A) was used for simultaneous determination of total amounts of triacylglycerides, diacylglycerides, monoacylglycerides and fatty acid methyl esters in alcoholysis of different oil (cotton, canola, sunflower, corn and soybean) samples. Analyses were carried out at 40 deg C for 20 min using a gradient of methanol (MeOH) and 2-propanol-hexane 5:4 (v/v) (PrHex): 100% of MeOH in 0 min, 50% of MeOH and 50% of PrHex in 10 min maintained with isocratic elution for 10 min. Another HPLC-UV method (method B) with acetonitrile isocratic elution for 34 min was used to determine the fatty acid composition of oils analyzing their methyl ester derivatives. Contents were determined with satisfactory repeatability (relative standard deviation, RSD < 3%), linearity (r{sup 2} > 0.99) and sensitivity (limit of quantification). Method B was compared with an official gas chromatographic method with flame ionization detection (GC-FID) from American Oil Chemists' Society (AOCS) in the determination of fatty acid methyl esters (FAME) in biodiesel real samples. (author)

8. Graphene Oxide Nanoparticles and Their Influence on Chromatographic Separation Using Polymeric High Internal Phase Emulsions

Directory of Open Access Journals (Sweden)

Sidratul Choudhury

2017-02-01

Full Text Available This work presents the first instance of reversed-phase liquid chromatographic separation of small molecules using graphene oxide nanoparticle-modified polystyrene-divinylbenzene polymeric high internal phase emulsion (GONP PS-co-DVB polyHIPE materials housed within a 200-µm internal diameter (i.d. fused silica capillary. The graphene oxide nanoparticle (GONP-modified materials were produced as a potential strategy to increase both the surface area limitations and the reproducibility issues observed in monolithic stationary phase materials. GONP PS-co-DVB polyHIPEs were found to have a surface area up to 40% lower than unmodified polymeric high internal phase emulsion (polyHIPE stationary phases. However, despite having a surface area significantly lower than that of the unmodified material, the GONP-modified polyHIPEs demonstrated superior analyte adsorption properties. Reducing the GONP material did not have any significant impact on elution order or retention factor of the analytes, which was most likely due to low GONP loading attributed to the 250-nm GONPs utilised. The lower surface area of GONP-modified polyHIPEs provided similar separation efficiency and increased repeatability from injection to injection resulting in % relative standard deviations (%RSDs of less than 0.6%, indicating the potential offered by graphene oxide (GO-modified polyHIPES in flow through applications such as adsorption or separation processes.

9. Evaluation of chromatographic columns packed with semi- and fully porous particles for benzimidazoles separation.

Science.gov (United States)

Gonzalo-Lumbreras, Raquel; Sanz-Landaluze, Jon; Cámara, Carmen

2015-07-01

The behavior of 15 benzimidazoles, including their main metabolites, using several C18 columns with standard or narrow-bore diameters and different particle size and type were evaluated. These commercial columns were selected because their differences could affect separation of benzimidazoles, and so they can be used as alternative columns. A simple screening method for the analysis of benzimidazole residues and their main metabolites was developed. First, the separation of benzimidazoles was optimized using a Kinetex C18 column; later, analytical performances of other columns using the above optimized conditions were compared and then individually re-optimized. Critical pairs resolution, analysis run time, column type and characteristics, and selectivity were considered for chromatographic columns comparison. Kinetex XB was selected because it provides the shortest analysis time and the best resolution of critical pairs. Using this column, the separation conditions were re-optimized using a factorial design. Separations obtained with the different columns tested can be applied to the analysis of specific benzimidazoles residues or other applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

10. Comparison of twin-cell centrifugal partition chromatographic columns with different cell volume.

Science.gov (United States)

Goll, Johannes; Audo, Gregoire; Minceva, Mirjana

2015-08-07

Two twin-cell centrifugal partition chromatographic columns (SCPC 250 and SCPE-250-BIO, Armen Instrument, France) with the same column volume but different cell size and number were compared in terms of stationary phase retention and column efficiency. The columns were tested with two types of solvent systems: a commonly used organic solvent based biphasic system from the ARIZONA solvent system family and a polymer/salt based aqueous two phase system (ATPS). The efficiency of the columns was evaluated by pulse injection experiments of two benzenediols (pyrocatechol and hydroquinone) in the case of the ARIZONA system and a protein mixture (myoglobin and lysozyme) in the case of the ATPS. As result of high stationary phase retention, the column with the lower number of larger twin-cells (SCPE-250-BIO) is suitable for protein separations using ATPS. On the other hand, due to higher column efficiency, the column with the greater number of smaller cells (SCPC 250) is superior for batch elution separations performed with standard liquid-liquid chromatography organic solvent based biphasic systems. Copyright © 2015 Elsevier B.V. All rights reserved.

11. Graphitic carbon nitride as high-resolution stationary phase for gas chromatographic separations.

Science.gov (United States)

Zheng, Yunzhong; Qi, Meiling; Fu, Ruonong

2016-07-08

This work presents the first example of utilization of graphitic carbon nitride (g-C3N4) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated g-C3N4 column showed the column efficiencies of 3760 plates/m and weak polarity. Its resolving capability and retention behaviours were investigated by using the Grob test mixture, and mixtures of diverse types of analytes, and structural and positional isomers. The results showed superior separation performance of the g-C3N4 stationary phase for some critical analytes and preferential retention for aromatic analytes. Specifically, it exhibited high-resolution capability for aromatic and aliphatic isomers such as methylnaphthalenes and dimethylnaphthalenes, phenanthrene and anthracene and alkane isomers. In addition, g-C3N4 column showed excellent thermal stability up to 280°C and good repeatability with relative standard deviation (RSD) values less than 0.09% for intra-day, below 0.23% for inter-day and in the range of 1.9-8.4% for between-column, respectively. The advantageous separation performance shows the potential of g-C3N4 and related materials as stationary phase in GC and other separation technologies. Copyright © 2016 Elsevier B.V. All rights reserved.

12. Graphitic carbon nitride nanofibers in seaweed-like architecture for gas chromatographic separations.

Science.gov (United States)

Zheng, Yunzhong; Han, Qing; Qi, Meiling; Qu, Liangti

2017-05-05

Seaweed-like graphitic carbon nitride (g-C 3 N 4 ) has a unique porous architecture composed of interlocking g-C 3 N 4 nanofibers (NF-C 3 N 4 ) with much higher surface area than bulk g-C 3 N 4 and shows good potential in separation science. This work investigated the separation performance of NF-C 3 N 4 as stationary phase for capillary gas chromatographic (GC) separations. The NF-C 3 N 4 column exhibits weak polarity and high column efficiency of 4728 plates/m for n-dodecane. Importantly, it displays good separation performance for a wide range of analytes and shows different retention behaviors from the bulk g-C 3 N 4 column and commercial HP-5MS column with 5% phenylpolysiloxane. Particularly, it shows high resolving capability for both aliphatic and aromatic isomers. In addition, NF-C 3 N 4 column has high thermal stability up to 280°C and good separation repeatability with relative standard deviation (RSD) values in the range of 0.29-0.61% for intra-day, 0.56-1.1% for inter-day and 2.0-4.9% for between-column, respectively. Moreover, it was applied for the determination of isomer impurities in real samples, showing good potential in GC applications. Copyright © 2017 Elsevier B.V. All rights reserved.

13. Thin-layer chromatographic (TLC) separations and bioassays of plant extracts to identify antimicrobial compounds.

Science.gov (United States)

Kagan, Isabelle A; Flythe, Michael D

2014-03-27

A common screen for plant antimicrobial compounds consists of separating plant extracts by paper or thin-layer chromatography (PC or TLC), exposing the chromatograms to microbial suspensions (e.g. fungi or bacteria in broth or agar), allowing time for the microbes to grow in a humid environment, and visualizing zones with no microbial growth. The effectiveness of this screening method, known as bioautography, depends on both the quality of the chromatographic separation and the care taken with microbial culture conditions. This paper describes standard protocols for TLC and contact bioautography with a novel application to amino acid-fermenting bacteria. The extract is separated on flexible (aluminum-backed) silica TLC plates, and bands are visualized under ultraviolet (UV) light. Zones are cut out and incubated face down onto agar inoculated with the test microorganism. Inhibitory bands are visualized by staining the agar plates with tetrazolium red. The method is applied to the separation of red clover (Trifolium pratense cv. Kenland) phenolic compounds and their screening for activity against Clostridium sticklandii, a hyper ammonia-producing bacterium (HAB) that is native to the bovine rumen. The TLC methods apply to many types of plant extracts and other bacterial species (aerobic or anaerobic), as well as fungi, can be used as test organisms if culture conditions are modified to fit the growth requirements of the species.

14. An inverse gas chromatographic methodology for studying gas-liquid mass transfer.

Science.gov (United States)

Paloglou, A; Martakidis, K; Gavril, D

2017-01-13

A novel methodology of reversed flow inverse gas chromatography (RF-IGC) is presented. It permits the simultaneous determination of mass transfer coefficients across the gas liquid interface as well as the respective solubility parameters and thermodynamic functions of dissolution of gases into liquids. The standard deviation of the experimentally determined parameters is estimated for first time, which combined with the successful comparison of the values of the present parameters with other literature ones ascertain the reliability of the methodology. Another novelty of the present work is that the chromatographic sampling of the physicochemical phenomena is done without performing the usual flow reversals procedure. Vinyl chloride monomer's (VCM) interaction with various composition liquid foods: orange juice, milk and olive oil was used as model system. The present transfer rates are controlled by the gas film at lower temperatures, but at higher temperatures the resistances in both films tend to become equal. The found liquid diffusivity values express the total mass transfer from the gas phase into the liquid's bulk and they decrease with rising temperature, as the solubilities of gases in liquids do. Solubility, expressed by Henry's law constant and the mean values of interfacial thickness are of the same order of magnitude to literature ones. From the thermodynamic point of view, VCM dissolution in all liquids is accompanied by significant heat release and it is a slightly non-spontaneous process, near equilibrium, while the entropy change values are negative. Copyright © 2016 Elsevier B.V. All rights reserved.

15. Liquid chromatographic determination of urinary 2-thiothiazolidine-4-carboxylic acid, a biomarker of carbon disulphide exposure.

Science.gov (United States)

Lee, B L; Yang, X F; New, A L; Ong, C N

1995-06-23

An effective gradient high-performance liquid chromatographic method for baseline separation of urinary 2-thiothiazolidine-4-carboxylic acid (TTCA), with photodiode array detection at 271 nm was described. o-Methylhippuric acid was used as an internal standard (I.S.). A 1-ml urine sample was saturated with 300 mg of sodium sulphate, acidified with 100 microliters of 6 M hydrochloric acid, extracted twice with 2 ml of diethyl ether, and after evaporation, the residue was taken up in 1 ml of 0.1% (v/v) phosphoric acid. The two mobile phases used for gradient elution were: (A) 10 mM ammonium dihydrogenphosphate (pH 3.5) and (B) same concentration of buffer but containing 20% (v/v) of methanol (pH 4.8). The flow-rate was set at 1.0 ml/min. TTCA and I.S. were detected at 2.2 and 9.1 min, respectively. The method was validated with urine samples collected from normal subjects and workers occupationally exposed to carbon disulphide. The present method enables the detection of urinary TTCA at a concentration of 0.025 mg/l. Analytical recovery and reproducibility generally exceeded 90%. The proposed method is considered more sensitive, specific and reliable than other existing methods.

16. Characterisation of cold plasma treated beef and dairy lipids using spectroscopic and chromatographic methods.

Science.gov (United States)

Sarangapani, Chaitanya; Ryan Keogh, David; Dunne, Julie; Bourke, Paula; Cullen, P J

2017-11-15

The efficacy of cold plasma for inactivation of food-borne pathogens in foods is established. However, insights on cold plasma-food interactions in terms of quality effects, particularly for oils and fats, are sparse. This study evaluated plasma-induced lipid oxidation of model matrices, namely dairy and meat fats. Product characterisation was performed using FTIR, 1 H NMR and chromatographic techniques. The oxidation of lipids by cold plasma followed the Criegee mechanism and typical oxidation products identified included ozonides, aldehydes (hexanal, pentenal, nonanal and nonenal) and carboxylic acids (9-oxononanoic acid, octanoic acid, nonanoic acid), along with hydroperoxides (9- and 13-hydroperoxy-octadecadienoylglycerol species). However, these oxidation products were only identified following extended treatment times of 30min and were also a function of applied voltage level. Understanding cold plasma interactions with food lipids and the critical parameters governing lipid oxidation is required prior to the industrial adoption of this technology for food products with high fat contents. Copyright © 2017 Elsevier Ltd. All rights reserved.

17. Evaluation of ACE inhibitors lipophilicity using in silico and chromatographically obtained hydrophobicity parameters

Directory of Open Access Journals (Sweden)

2013-01-01

Full Text Available The aim of this study was to compare different calculation methods to determine lipophilicity, expressed as logP value, of seven ACE inhibitors (enalapril, quinapril, fosinopril, lisinopril, cilazapril, ramipril, and benazapril with significantly different structure. Experimentally determined n-octanol/water partition coefficients, logPO/W values, were obtained from relevant literature. The correlations between all collected logP values were studied and the best agreements between calculated logP and experimentally determined logPO/W values, were observed for KOWWINlogP or MilogP values (r = 0.999 or r = 0.974, respectively. The correlations between all collected logP values and chromatographically (reversed-phase thin-layer chromatography obtained hydrophobicity parameters, RM0 and C0, were established. The good correlations (r > 0.90 were obtained in the majority of relationships. The KOWWINlogP was established as the most suitable hydrophobicity parameter of investigated group of ACE inhibitors with r = 0.981 for correlation with RM0 and r = 0.977 for correlation with C0 parameters (water-methanol mobile phase. Using multiple linear regressions, it was established that application of two selected logP, calculated by different mathematical approaches, led to very good correlation due to the benefits of both calculation methods. The good relationships indicate that the computed logP, with careful selection of method calculation, can be useful in ACE inhibitors lipophilicity evaluation, as high-throughput screening technique.

18. New gas chromatographic instrumentation for studying the action of sulfur dioxide on marbles.

Science.gov (United States)

Bakaoukas, Nikolaos; Kapolos, John; Koliadima, Athanasia; Karaiskakis, George

2005-09-16

Reversed-flow gas chromatography, which is a sub-technique of inverse gas chromatography, is an experimental arrangement simulating a simple model for the action of air pollutants on buildings and monuments, in laboratory scale. By using a commercial gas chromatograph and an appropriate mathematical analysis, kinetic parameters such as rate constants for adsorption k1, adsorption/desorption kR and surface reaction k2, as well as surface diffusion coefficients Dgamma, deposition velocities Vd and reaction probabilities gamma of SO2 on marble surfaces at different temperatures (303.15-353.15 K) in the presence or in the absence of protective materials (an acrylic copolymer, Paraloid B-72 or a siloxane, CTS Silo 111) were calculated. From the above mentioned physicochemical quantities the ability of the examined materials to minimize the dry deposition of SO2 on marble is carrying out and a possible mechanism for the interaction between SO2 and Paraloid B-72 was suggested. Both materials (CTS SILO 111 and Paraloid B-72) are good enough for protecting marble against SO2 at low temperatures (303.15-323.15), while at high temperatures (333.15-353.15), siloxane seems to protect marble better than acrylic copolymer.

19. Improved liquid chromatographic method for determination of aflatoxins in peanut butter and other commodities.

Science.gov (United States)

Tarter, E J; Hanchay, J P; Scott, P M

1984-01-01

A combination of the extraction and cleanup procedures of Pons and Franz with the liquid chromatographic (LC) derivatization technique of Beebe is proposed as an accurate, precise, and sensitive method for determination of aflatoxins B1, B2, G1, and G2 in various foodstuffs. Mean recoveries of total aflatoxins added in the range 15-34 ng/g to peanut butter were 86-94% in 2 laboratories. Recovery of total aflatoxins (30 ng/g) from shelled peanuts, shelled Brazil nuts, pistachios, cashews, walnuts, and filberts exceeded 86% and from pumpkin seeds was 80%. Coefficients of variation for total aflatoxins were less than 7% for spiked samples and 15% for peanuts naturally contaminated with 16.7 ng/g of total aflatoxin (B1 + B2). Analyses of peanut meal, yellow corn meal, and peanut butter check samples (AOCS Smalley Series 1980/81 and 1981/82, IARC Series 1982/83) by this method compared favorably with reported averages. The detection limit is about 0.3 ng/g for each aflatoxin.

20. Ion chromatographic determination of fluoride and chloride in UO2 using microbore anion exchange columns

International Nuclear Information System (INIS)

Kelkar, Anoop; Meena, D.L.; Das, D.K.; Behere, P.G.; Mohd Afzal

2015-01-01

Chemical characterization of nuclear fuels is required to ensure that nuclear fuel meets the technical specifications of the fuel. Trace non- metallic impurities like Cl and F is important as they affect clad corrosion. Their effect is more severe in presence of moisture. Chlorine and Fluorine is routinely analysed by ion selective electrode or conventional ion chromatography after pyrohydrolyzing the sample in moist O 2 atmosphere at 950°. Both the technique generates large quantity of liquid waste. Generally 1 ml/min flow rate required for the separation of F - and Cl - in conventional ion-chromatographic separation of F - and Cl - on 4.6- 4.0 mm id analytical column. The waste produced per sample injection is ∼ 30-40 ml with suppressed conductivity detection in ion chromatography. There is a need to reduce this analytical waste in analyzing the radioactive samples for the determination of F - and Cl - . Waste generation could be effectively reduced by using microbore anion exchange analytical column. Present paper describe the use of Metrosep A Supp 16 - 100/2.0 column with Na 2 CO 3 +NaOH mobile phase for the determination of F - and Cl - in UO 2 samples using suppressed conductivity detection

1. Determination of H-atom reaction rate constants by the competition kinetic technique using riboflavin as a standard solute [Paper No. RD-7

International Nuclear Information System (INIS)

Kishore, Kamal; Moorthy, P.N.; Rao, K.N.

1982-01-01

Riboflavin has been used as a standard solute to evaluate H-atom rate constants of other solutes by steady state radiolytic competition kinetic method. The bleaching of absorbance of riboflavin at 445 nm as a result of its reaction with H-atoms is made use of in estimating its decomposition. The merits and demerits of this method are discussed. (author)

2. Catalogue of EDFs technical specifications (HN reference). Centre of standardization; Catalogue des specifications techniques EDF (reference HN). Centre de normalisation

Energy Technology Data Exchange (ETDEWEB)

1998-12-31

This document edited by Electricite de France (EdF), is a catalogue of the French standard documents relative to any type of electrical material and equipment and which contain the technical specifications of these materials and equipments. A brief description of these specifications is given for each type of material or equipment listed. (J.S.)

3. Strain analysis in CRT candidates using the novel segment length in cine (SLICE) post-processing technique on standard CMR cine images

NARCIS (Netherlands)

Zweerink, A.; Allaart, C.P.; Kuijer, J.P.A.; Wu, L.; Beek, A.M.; Ven, P.M. van de; Meine, M.; Croisille, P.; Clarysse, P.; Rossum, A.C. van; Nijveldt, R.

2017-01-01

OBJECTIVES: Although myocardial strain analysis is a potential tool to improve patient selection for cardiac resynchronization therapy (CRT), there is currently no validated clinical approach to derive segmental strains. We evaluated the novel segment length in cine (SLICE) technique to derive

4. Comparison of high-performance liquid chromatographic and thin-layer chromatographic methods for determination of aloin in herbal products containing Aloe vera.

Science.gov (United States)

Ramírez Durón, Rosalba; Ceniceros Almaguer, Lucía; Cavazos Rocha, Norma Cecilia; Silva Flores, Perla Giovanna; De Torres, Noemí Waksman

2008-01-01

Aloe vera is a medicinal plant used worldwide to treat a variety of conditions and, as such, has important commercial value. Aloin is a principal component of aloe vera leaves and is used for quality control of products containing it. A semiquantitative thin-layer chromatographic (TLC) method for determining the concentration of aloin in aloe-based products was validated. The results were similar to those of a validated high-performance liquid chromatographic method; therefore, TLC, which is a simple, sensitive, specific, rapid, and cheap method, may be ideal for use in any laboratory for routine analysis of commercial products containing aloe vera.

5. HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES

Science.gov (United States)

High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) was obtained on polysaccharide enantioselective HPLC columns using alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, fonofos, fenamiph...

6. Derivatization reactions in the gas—liquid chromatographic analysis of drugs in biological fluids

NARCIS (Netherlands)

Hulshoff, A.; Lingeman, H.

1984-01-01

Alkylation, acylation, silylation and other derivatization reactions applied to the gas chromatographic analysis of drugs in biological matrices are reviewed. Reaction conditions are discussed in relation to reaction mechanisms. Detector-oriented labelling of drugs, and derivatization with chiral

7. Miniaturized MEMS-Based Gas Chromatograph for High Inertial Loads Associated with Planetary Missions, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Thorleaf Research, Inc. proposes to develop a rugged, miniaturized, low power MEMS-based gas chromatograph (GC) capable of handling the high inertial loads...

8. Refractive surgery: Is the new small-incision lenticule extraction (SMILE) technique equal to or better than the standard flap-and-ablation (FS-LASIK) technique for treating high-degree myopia?

DEFF Research Database (Denmark)

Hansen, Rasmus Søgaard; Lyhne, Niels; Grauslund, Jakob

Field: Ophthalmology Introduction: Corneal laser surgery for myopia (nearsightedness) is one of the most performed surgical procedures today. FS-LASIK has been the dominating surgical technique for almost two decades, but a shift to the new less invasive SMILE technique might be underway. However...... the literature on SMILE is sparse, especially for high-degree myopia (six or more dioptres (D)). We hypothesize that the accuracy, efficacy, stability and safety after SMILE is equal to or better than FS-LASIK up to three months post-operatively for high-degree myopia. Methods: Retrospective study of 1214 eyes...... treated with SMILE or FS-LASIK for high-degree myopia from 2011-2013 at the Department of Ophthalmology, Odense University Hospital, Denmark. Inclusion criteria: Best spectacle-corrected visual acuity (BSCVA) of 20/25 or better on Snellen chart, and no other ocular condition than high-degree myopia...

9. Fast and Standardized Skin Grafting of Leg Wounds With a New Technique: Report of 2 Cases and Review of Previous Methods.

Science.gov (United States)

Hamnerius, Nils; Wallin, Ewa; Svensson, Åke; Stenström, Pernilla; Svensjö, Tor

2016-01-01

Chronic leg ulcers remain a challenge to the treating physician. Such wounds often need skin grafts to heal. This necessitates a readily available, fast, simple, and standardized procedure for grafting. The aim of this work was to test a novel method developed for outpatient transplant procedures. The procedure employs a handheld disposable dermatome and a roller mincer that cut the skin into standardized micrografts that can be spread out onto a suitable graft bed. Wounds were followed until healed and photographed. The device was successfully used to treat and close a traumatic lower limb wound and a persistent chronic venous leg ulcer. The donor site itself healed by secondary intent with minimal cosmetic impairment. The method was successfully used to graft 2 lower extremity wounds.

10. Chromatographic fingerprint similarity analysis for pollutant source identification.

Science.gov (United States)

Xie, Juan-Ping; Ni, Hong-Gang

2015-12-01

In the present study, a similarity analysis method was proposed to evaluate the source-sink relationships among environmental media for polybrominated diphenyl ethers (PBDEs), which were taken as the representative contaminants. Chromatographic fingerprint analysis has been widely used in the fields of natural products chemistry and forensic chemistry, but its application to environmental science has been limited. We established a library of various sources of media containing contaminants (e.g., plastics), recognizing that the establishment of a more comprehensive library allows for a better understanding of the sources of contamination. We then compared an environmental complex mixture (e.g., sediment, soil) with the profiles in the library. These comparisons could be used as the first step in source tracking. The cosine similarities between plastic and soil or sediment ranged from 0.53 to 0.68, suggesting that plastic in electronic waste is an important source of PBDEs in the environment, but it is not the only source. A similarity analysis between soil and sediment indicated that they have a source-sink relationship. Generally, the similarity analysis method can encompass more relevant information of complex mixtures in the environment than a profile-based approach that only focuses on target pollutants. There is an inherent advantage to creating a data matrix containing all peaks and their relative levels after matching the peaks based on retention times and peak areas. This data matrix can be used for source identification via a similarity analysis without quantitative or qualitative analysis of all chemicals in a sample. Copyright © 2015 Elsevier Ltd. All rights reserved.

11. Liquid chromatographic determination of seven antioxidants in dry food.

Science.gov (United States)

Page, B D; Charbonneau, C F

1989-01-01

The liquid chromatographic determinative step of the official method for propyl gallate, trihydroxybutyrophenone, tert-butylhydroquinone, nordihydroguaiaretic acid, butylated hydroxyanisole (BHA), 3,5-di-tert-butyl-4-hydroxymethylphenol, and butylated hydroxytoluene (BHT) in fats and oils has been applied to their determination in a number of dry foods. A representative sample (10 g) is homogenized first with hexane (25 mL), then with 5 mL added water, and finally with 75 mL added acetonitrile. The hexane and acetonitrile are decanted, filtered, and separated; the hexane and rehydrated food are reextracted with 2 additional portions of acetonitrile, and the combined acetonitrile extracts are concentrated and diluted to 10 mL. An aliquot is analyzed as described in the official method, using a 150 x 4.6 mm 5 microns C-18 column. The need for rehydration to maximize the recovery of BHA and other antioxidants from marketplace dry food samples such as potato flakes, dry coffee whiteners, and dessert topping mixes was demonstrated. Rehydration was not required for cheese snacks, breakfast cereals, cake mixes, and some other foods. The need for rehydration should be determined by analyzing other foods with and without the addition of water. Potato and corn chips, popcorn and cheese snacks, breakfast cereals, dry beverage mixes, rice, potato flakes, french fried potatoes, and cake mixes were spiked with the above antioxidants at 10-50 ppm. Overall recoveries ranged from 64.3 to 105.6% and repeatabilities ranged from 0.7 to 10.8%. A total of 109 samples of the above foods were analyzed, and 64% contained detectable (greater than 1-2 ppm) antioxidants, mainly BHA and BHT.

12. Standardized Time-Series and Interannual Phenological Deviation: New Techniques for Burned-Area Detection Using Long-Term MODIS-NBR Dataset

Directory of Open Access Journals (Sweden)

Osmar Abílio de Carvalho Júnior

2015-05-01

Full Text Available Typically, digital image processing for burned-areas detection combines the use of a spectral index and the seasonal differencing method. However, the seasonal differencing has many errors when applied to a long-term time series. This article aims to develop and test two methods as an alternative to the traditional seasonal difference. The study area is the Chapada dos Veadeiros National Park (Central Brazil that comprises different vegetation of the Cerrado biome. We used the MODIS/Terra Surface Reflectance 8-Day composite data, considering a 12-year period. The normalized burn ratio was calculated from the band 2 (250-meter resolution and the band 7 (500-meter resolution reasampled to 250-meter. In this context, the normalization methods aim to eliminate all possible sources of spectral variation and highlight the burned-area features. The proposed normalization methods were the standardized time-series and the interannual phenological deviation. The standardized time-series calculate for each pixel the z-scores of its temporal curve, obtaining a mean of 0 and a standard deviation of 1. The second method establishes a reference curve for each pixel from the average interannual phenology that is subtracted for every year of its respective time series. Optimal threshold value between burned and unburned area for each method was determined from accuracy assessment curves, which compare different threshold values and its accuracy indices with a reference classification using Landsat TM. The different methods have similar accuracy for the burning event, where the standardized method has slightly better results. However, the seasonal difference method has a very false positive error, especially in the period between the rainy and dry seasons. The interannual phenological deviation method minimizes false positive errors, but some remain. In contrast, the standardized time series shows excellent results not containing this type of error. This

13. Simultaneous liquid-chromatographic quantitation of salicylic acid, salicyluric acid, and gentisic acid in urine.

Science.gov (United States)

Cham, B E; Bochner, F; Imhoff, D M; Johns, D; Rowland, M

1980-01-01

We have developed a specific and sensitive method for the determination of salicylic acid, salicyluric acid, and gentisic acid in urine. Any proteins present are precipitated with methyl cyanide. After centrifugation, an aliquot of the supernate is directly injected into an octadecyl silane reversed-phase chromatographic column, then eluted with a mixture of water, butanol, acetic acid, and sodium sulfate, and quantitated at 313 nm by ultraviolet detection according to peak-height ratios (with internal standard, o-methoxybenzoic acid) or peak heights (no internal standard). The method allows estimates within 25 min. Sensitivity was 0.2 mg/L for gentisic acid, and 0.5 mg/L for both salicyluric and salicylic acid (20-micro L injection volume); response was linear with concentration to at least 2.000 g/L for salicylic acid and metabolites. Analytical recovery of salicylic acid and metabolites from urine is complete. Intra-assay precision (coefficient of variation) is 5.52% at 7.5 mg/L for salicylic acid, 5.01% at 9.33 mg/L for salicyluric acid, and 3.07% at 7.96 mg/L for gentisic acid. Interassay precision is 7.32% at 7.51 mg/L for salicylic acid, 5.52% at 8.58 mg/L for salicyluric acid, and 3.97% at 8.32 mg/L for gentisic acid. We saw no significant interference in urine from patients being treated with various drugs other than aspirin.

14. Proposal for inclusion of the risk based inspection technique in Regulatory Standard NR 13; Proposta de inclusao da tecnica de inspecao baseada em risco na Norma Regulamentadora NR 13

Energy Technology Data Exchange (ETDEWEB)

Esteves, Vinicius Teixeira; Lima, Marco Aurelio Oliveira [Det Norske Veritas Ltda. (DNV), Rio de Janeiro, RJ (Brazil)

2012-07-01

In Brazil, the Regulatory Standard n. 13 (NR 13) establishes requirements for the inspection of boilers and pressure vessels which has main objective of preventing accidents with these types of equipment. Additionally, it has the Risk-Based Inspection (RBI) technique as an effective way to manage the mechanical integrity of various types of static mechanical equipment by through an inspection planning based on the risk factor. In this study, it is being proposed to include the RBI technique, in the NR 13, for the planning and definition of periods for the safety inspection of boilers and pressure vessels in order to promote an increase in the operational safety in process industries in Brazil. In this study it was carried out a critical analysis of NR 13 and RBI, and beyond that a bibliographic research of various international documents that relate the operational safety of pressurized equipment with the inspection activity, and the acceptability of RBI by governments, agencies and organizations around the world. It is considered that the inclusion and formal acceptance of RBI technique in the NR 13 must be accompanied by a rigorous control to avoid the 'trivialization' of its use and ensure the implementation rational, efficient and reliable. Finally, it was developed and suggested basic elements and minimum requirements to be inserted in the NR 13, to be attended, in order mandatory, by the companies that choose the implementation and use of the RBI technique as a tool for the planning of safety inspection of boilers and pressure vessels. It is concluded that the formal acceptance of the RBI technique in the NR 13 could aggregate much value to this standard, with regard to the prevention of accidents involving boilers or pressure vessels, and provide a technological jump to the companies that make use of RBI technique in Brazil. (author)

15. A randomized controlled trial comparing the AccuVein AV300 device to standard insertion technique for intravenous cannulation of anesthetized children.

Science.gov (United States)

Kaddoum, Roland N; Anghelescu, Doralina L; Parish, Mary E; Wright, Becky B; Trujillo, Luis; Wu, Jianrong; Wu, Yanan; Burgoyne, Laura L

2012-09-01

To evaluate the efficacy of the AccuVein AV300 device in improving the first-time success rate of intravenous cannulation of anesthetized pediatric patients. The AccuVein AV300 device was developed to assist venepuncture and intravenous cannulation by enhancing the visibility of superficial veins. It uses infrared light to highlight hemoglobin so that blood vessels are darkly delineated against a red background. Patients were randomized to cannulation with the AccuVein AV300 device or standard insertion by experienced pediatric anesthesiologists. An observer recorded the number of skin punctures and cannulation attempts required, and the time between tourniquet application and successful cannulation or four skin punctures, whichever came first. There were 146 patients with a median age of 4.6 years (range, 0.18-17.1 years), 46.6% were male, 80.8% were light skin colored, and 15.7% were younger than 2 years. The first-attempt success rates were 75% (95% CI, 63.8-84.2%) using AV300 and 73% (95% CI, 61.9-81.9%) using the standard method (P = 0.85). Patients with dark or medium skin color were 0.38 times less likely to have a successful first attempt than patients with light skin color. The difference between the two treatment groups in number of skin punctures and the time to insertion was not significant. Although the AV300 was easy to use and improved visualization of the veins, we found no evidence that it was superior to the standard method of intravenous cannulation in unselected pediatric patients under anesthesia. © 2012 Blackwell Publishing Ltd.

16. Comparison of American Fisheries Society (AFS) standard fish sampling techniques and environmental DNA for characterizing fish communities in a large reservoir

Science.gov (United States)

Perez, Christina R.; Bonar, Scott A.; Amberg, Jon J.; Ladell, Bridget; Rees, Christopher B.; Stewart, William T.; Gill, Curtis J.; Cantrell, Chris; Robinson, Anthony

2017-01-01

Recently, methods involving examination of environmental DNA (eDNA) have shown promise for characterizing fish species presence and distribution in waterbodies. We evaluated the use of eDNA for standard fish monitoring surveys in a large reservoir. Specifically, we compared the presence, relative abundance, biomass, and relative percent composition of Largemouth Bass Micropterus salmoides and Gizzard Shad Dorosoma cepedianum measured through eDNA methods and established American Fisheries Society standard sampling methods for Theodore Roosevelt Lake, Arizona. Catches at electrofishing and gillnetting sites were compared with eDNA water samples at sites, within spatial strata, and over the entire reservoir. Gizzard Shad were detected at a higher percentage of sites with eDNA methods than with boat electrofishing in both spring and fall. In contrast, spring and fall gillnetting detected Gizzard Shad at more sites than eDNA. Boat electrofishing and gillnetting detected Largemouth Bass at more sites than eDNA; the exception was fall gillnetting, for which the number of sites of Largemouth Bass detection was equal to that for eDNA. We observed no relationship between relative abundance and biomass of Largemouth Bass and Gizzard Shad measured by established methods and eDNA copies at individual sites or lake sections. Reservoirwide catch composition for Largemouth Bass and Gizzard Shad (numbers and total weight [g] of fish) as determined through a combination of gear types (boat electrofishing plus gillnetting) was similar to the proportion of total eDNA copies from each species in spring and fall field sampling. However, no similarity existed between proportions of fish caught via spring and fall boat electrofishing and the proportion of total eDNA copies from each species. Our study suggests that eDNA field sampling protocols, filtration, DNA extraction, primer design, and DNA sequencing methods need further refinement and testing before incorporation into standard

17. Comparative Studies on the Radiolabeling and Chromatographic Purification of Some Medically Important Compounds

International Nuclear Information System (INIS)

El-Gizawy, M.A.E.

2013-01-01

18. Automated-process gas-chromatograph system for use in accelerated corrosion testing of HTGR core-support posts

International Nuclear Information System (INIS)

Harper, R.E.; Herndon, P.G.

1982-01-01

An automated-process gas chromatograph is the heart of a gaseous-impurities-analysis system developed for the Oak Ridge National Laboratory Core Support Performance Test, at which graphite core-support posts for high-temperature gas-cooled fission reactors are being subjected to accelerated corrosion tests under tightly controlled conditions of atmosphere and temperature. Realistic estimation of in-core corrosion rates is critically dependent upon the accurate measurement of low concentrations of CO, CO 2 , CH 4 , H 2 , and O 2 in the predominantly helium atmosphere. In addition, the capital and labor investment associated with each test puts a premium upon the reliability of the analytical system, as excessive downtime or failure to obtain accurate data would result in unacceptable costs and schedule delays. After an extensive survey of available measurement techniques, gas chromatography was chosen for reasons of accuracy, flexibility, good-performance record, and cost

19. Reversed phase chromatographic behaviour of Pu (III), Pu (IV) and Pu (VI) in presence of α-hydroxyisobutyric acid

International Nuclear Information System (INIS)

Jaison, P.G.; Telmore, V.M.; Kumar, Pranaw

2016-01-01

Understanding the aqueous chemistry of plutonium is important in process conditions as well as in environmental conditions. Since plutonium possesses multiple oxidation states which can coexist in solution, a reliable method for the identification of these oxidation states is essential to understand its physical and chemical processes. The identification of plutonium oxidation states is conventionally determined through a series of liquid-liquid extraction procedures using selective extractants. Spectroscopic and laser based techniques also have been used for the identification of its oxidation state in solutions. Liquid chromatographic behavior of different oxidation states of Pu and other actinide ions is reported to correlate their retention behaviour with stability constants. Objective of the present work is to study the reversed phase chromatography behavior of the three oxidation states of plutonium viz. Pu(III), Pu(IV) and Pu(VI) in presence of á-hydroxyisobutyric acid (HIBA) as an eluent

20. Variability of diagnostic approach, surgical technique, and medical management for children with biliary atresia in Canada - Is it time for standardization?

Science.gov (United States)

Stagg, Hayden; Cameron, Brian H; Ahmed, Najma; Butler, Alison; Jimenez-Rivera, Carolina; Yanchar, Natalie L; Martin, Steve R; Emil, Sherif; Anthopoulos, George; Schreiber, Richard A; Laberge, Jean-Martin

2017-05-01

The Canadian 4-year native liver survival rate for biliary atresia (BA) after Kasai Portoenterostomy (KP) is 39%. The Canadian Biliary Atresia Registry (CBAR) was used to examine variability of surgical and medical management of BA. Gastroenterologists and surgeons in all 14 Canadian pediatric tertiary centers were invited to complete an online survey of their BA management practices. Of gastroenterologists, diagnostic procedures included liver biopsy (92%), HIDA scan (58%), and percutaneous cholangiogram (46%). Surgeons reported Roux-en-Y lengths of 20-50cm with 78% avoiding diathermy at the portal plate; 16% performed laparoscopic exploration, but none laparoscopic KP. Postoperative corticosteroids and antibiotics were used by 24% and 85% of gastroenterologists, respectively, with similar rates for surgeons. At discharge, gastroenterologists prescribed oral antibiotics (80%), and ursodeoxycholic acid (95%), while surgeons reported lower rates (62% and 55%). Considerable variation existed in follow-up monitoring. No center had a standard protocol for evaluating suspected cholangitis. There was a lack of consensus for defining failed KP and referral criteria for transplant evaluation. In Canada, treatment of BA is not centralized, and there is variability in diagnostic approaches and management. Collaboration through CBAR will allow for implementation and evaluation of standardized surgical and medical management with a goal to improve outcomes. Survey study. Level IV evidence. Copyright © 2017 Elsevier Inc. All rights reserved.

1. Porous Chromatographic Materials as Substrates for Preparing Synthetic Nuclear Explosion Debris Particles

International Nuclear Information System (INIS)

Harvey, Scott D.; Liezers, Martin; Antolick, Kathryn C.; Garcia, Ben J.; Sweet, Lucas E.; Carman, April J.; Eiden, Gregory C.

2013-01-01

In this study, we investigated several porous chromatographic materials as synthetic substrates for preparing surrogate nuclear explosion debris particles. The resulting synthetic debris materials are of interest for use in developing analytical methods. Eighteen metals, including some of forensic interest, were loaded onto materials by immersing them in metal solutions (556 mg/L of each metal) to fill the pores, applying gentle heat (110°C) to drive off water, and then treating them at high temperatures (up to 800°C) in air to form less soluble metal species. High-boiling-point metals were uniformly loaded on spherical controlled-pore glass to emulate early fallout, whereas low-boiling-point metals were loaded on core-shell silica to represent coated particles formed later in the nuclear fallout-formation process. Analytical studies were applied to characterize solubility, material balance, and formation of recalcitrant species. Dissolution experiments indicated loading was 1.5 to 3 times higher than expected from the pore volume alone, a result attributed to surface coating. Analysis of load solutions before and after filling the material pores revealed that most metals were passively loaded; that is, solutions filled the pores without active metal discrimination. However, niobium and tin concentrations were lower in solutions after pore filling, and were found in elevated concentrations in the final products, indicating some metals were selectively loaded. High-temperature treatments caused reduced solubility of several metal species, and loss of some metals (rhenium and tellurium) because volatile species were formed. Sample preparation reproducibility was high (the inter-batch relative standard deviation was 7.8%, and the intra-batch relative standard deviation was 0.84%) indicating that this material is suitable for use as a working standard for analytical methods development. We anticipate future standardized radionuclide-loaded materials will find use in

2. Industrial scale chromatographic separation of valuable compounds from biomass hydrolysates and side streams

Energy Technology Data Exchange (ETDEWEB)

Saari, P.

2011-06-15

Carbohydrates are composed of a number of various monosaccharides, glucose being the most abundant. Some of the monosaccharides are valuable compounds used in the food and pharmaceutical industries. They can be separated from biomass hydrolysates e.g. by chromatographic methods. In this thesis, chromatographic separation of valuable compounds using ion exchange resins was studied on an industrial scale. Of special interest were rare monosaccharides in biomass hydrolysates. A novel chromatographic separation process was developed for fucose, starting from pre-processed spent sulfite liquor. The core of the process consists of three chromatographic separations with different types of ion exchange resins. Chromatographic separation of galactose was tested with three biomass hydrolysates; lactose, gum arabic and hemicellulose hydrolysates. It was demonstrated that also galactose can be separated from complex carbohydrate mixtures. A recovery process for arabinose from citrus pectin liquid residual and for mannose from wood pulp hydrolysate were also developed and experimentally verified. In addition to monosaccharides, chromatographic separation of glycinebetaine from vinasse was examined with a hydrogen form weak acid cation exchange resin. The separation involves untypical peak formation depending, for example, on the pH and the cation composition. The retention mechanism was found to be hydrogen bonding between glycinebetaine and the resin. In the experimental part, all four resin types - strong acid cation, strong base anion, weak acid cation and weak base anion exchange resins - were used. In addition, adsorption equilibria data of seven monosaccharides and sucrose were measured with the resins in sodium and sulfate forms because such data have been lacking. It was found out that the isotherms of all sugars were linear under industrial conditions. A systematic method for conceptual process design and sequencing of chromatographic separation steps were developed

3. Does transcutaneous electrical nerve stimulation (TENS) alleviate the pain experienced during bone marrow sampling in addition to standard techniques? A randomised, double-blinded, controlled trial.

Science.gov (United States)

Tucker, David L; Rockett, Mark; Hasan, Mehedi; Poplar, Sarah; Rule, Simon A

2015-06-01

Bone marrow aspiration and trephine (BMAT) biopsies remain important tests in haematology. However, the procedures can be moderately to severely painful despite standard methods of pain relief. To test the efficacy of transcutaneous electrical nerve stimulation (TENS) in alleviating the pain from BMAT in addition to standard analgesia using a numerical pain rating scale (NRS). 70 patients requiring BMAT were randomised (1:1) in a double-blind, placebo-controlled trial. -35 patients received TENS impulses at a strong but comfortable amplitude (intervention group) and 35 patients received TENS impulses just above the sensory threshold (control group) (median pulse amplitude 20 and 7 mA, respectively). Patients and operators were blinded to group allocation. Pain assessments were made using a numerical pain scale completed after the procedure. No significant difference in NRS pain recalled after the procedure was detected (median pain score 5.7 (95% CI 4.8 to 6.6) in control vs 5.6 (95% CI 4.8 to 6.4) in the intervention group). However, 100% of patients who had previous experience of BMAT and >94% of participants overall felt they benefited from using TENS and would recommend it to others for this procedure. There were no side effects from the TENS device, and it was well tolerated. TENS is a safe, non-invasive adjunct to analgesia for reducing pain during bone marrow biopsy and provides a subjective benefit to most users; however, no objective difference in pain scores was detected when using TENS in this randomised controlled study. NCT02005354. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

4. Osteoarthritis of the carpometacarpal joint of the thumb: a new MR imaging technique for the standardized detection of relevant ligamental lesions

International Nuclear Information System (INIS)

Dumont, Clemens; Lerzer, Sebastian; Tezval, Mohammad; Stuermer, Klaus Michael; Vafa, Morad Ali; Lotz, Joachim; Dechent, Peter

2014-01-01

To assess ligament lesions and subluxations of the carpometacarpal joints of the thumbs (CMC I) of asymptomatic volunteers and of patients with CMC I osteoarthritis using advanced magnetic resonance imaging (MRI). A total of 20 CMC I joints of 14 asymptomatic volunteers (6 x both sides) and 28 CMC I joints of 22 patients (6 x both sides) with symptomatic and X-ray-diagnosed osteoarthritis of CMC I joints were studied. During extension, flexion, abduction and adduction of the thumb, the anterior oblique (AOL), intermetacarpal (IML), posterior oblique (POL) and dorsal radial (DRL) ligaments were evaluated using 3-T MRI on two standard planes, and translation of metacarpal I (MC I) was assessed. The MRI demonstrated that ligament lesions of the AOL and IML are frequent. Isolated rupture of the AOL was found in 6 of 28 (21 %), combined rupture of the AOL + IML in 5 of 28 (18 %) and isolated IML rupture in 4 of 28 (14 %) joints. The patients had a significantly increased dorsal translation of MC I during extension with a median of 6.4 mm vs. 5.4 mm in asymptomatic volunteers (p < 0.05). MRIs of CMC I in two standardized planes frequently show combined ligament ruptures. The dorsal subluxation of MC I, which is increased in patients, correlates with OA severity based on X-ray and can be quantified by MRI. For joint-preserving surgical procedures and for prosthesis implantation of the CMC I, we recommend performing an MRI in two planes of the thumb - extension and abduction - to evaluate the ligaments and dorsal subluxation of MC I. (orig.)

5. Osteoarthritis of the carpometacarpal joint of the thumb: a new MR imaging technique for the standardized detection of relevant ligamental lesions

Energy Technology Data Exchange (ETDEWEB)

Dumont, Clemens [University Medical Center Goettingen, Department of Trauma Surgery, Plastic and Reconstructive Surgery, Goettingen (Germany); Georg-August-Universitaet, Department of Trauma Surgery, Plastic and Reconstructive Surgery, Goettingen (Germany); Lerzer, Sebastian; Tezval, Mohammad; Stuermer, Klaus Michael [University Medical Center Goettingen, Department of Trauma Surgery, Plastic and Reconstructive Surgery, Goettingen (Germany); Vafa, Morad Ali; Lotz, Joachim [University Medical Center Goettingen, Department of Diagnostic Radiology and Interventional Radiology, Goettingen (Germany); Dechent, Peter [University Medical Center Goettingen, MR-Research in Neurology and Psychiatry, Department of Cognitive Neurology, Goettingen (Germany)

2014-10-15

To assess ligament lesions and subluxations of the carpometacarpal joints of the thumbs (CMC I) of asymptomatic volunteers and of patients with CMC I osteoarthritis using advanced magnetic resonance imaging (MRI). A total of 20 CMC I joints of 14 asymptomatic volunteers (6 x both sides) and 28 CMC I joints of 22 patients (6 x both sides) with symptomatic and X-ray-diagnosed osteoarthritis of CMC I joints were studied. During extension, flexion, abduction and adduction of the thumb, the anterior oblique (AOL), intermetacarpal (IML), posterior oblique (POL) and dorsal radial (DRL) ligaments were evaluated using 3-T MRI on two standard planes, and translation of metacarpal I (MC I) was assessed. The MRI demonstrated that ligament lesions of the AOL and IML are frequent. Isolated rupture of the AOL was found in 6 of 28 (21 %), combined rupture of the AOL + IML in 5 of 28 (18 %) and isolated IML rupture in 4 of 28 (14 %) joints. The patients had a significantly increased dorsal translation of MC I during extension with a median of 6.4 mm vs. 5.4 mm in asymptomatic volunteers (p < 0.05). MRIs of CMC I in two standardized planes frequently show combined ligament ruptures. The dorsal subluxation of MC I, which is increased in patients, correlates with OA severity based on X-ray and can be quantified by MRI. For joint-preserving surgical procedures and for prosthesis implantation of the CMC I, we recommend performing an MRI in two planes of the thumb - extension and abduction - to evaluate the ligaments and dorsal subluxation of MC I. (orig.)

6. Exploration and classification of chromatographic fingerprints as additional tool for identification and quality control of several Artemisia species.

Science.gov (United States)

Alaerts, Goedele; Pieters, Sigrid; Logie, Hans; Van Erps, Jürgen; Merino-Arévalo, Maria; Dejaegher, Bieke; Smeyers-Verbeke, Johanna; Vander Heyden, Yvan

2014-07-01

-analysis technique. Samples of different quality could be indicated on the score plots. No multi-component analysis was required to reach the goal. Furthermore, differences related to the origin of some of the not-certified samples were shown. The importance of the specific herbal part used for its identification was also presented. In addition, no differences were observed among fingerprints of lyophilised or conditioned-air dried samples. Finally, a classification technique, Soft Independent Modelling by Class Analogy (SIMCA), was successfully evaluated as identification technique for unknown samples. Six additional Artemisia species (29 herbal samples) were identified as not belonging to any of the four modelled classes. The developed chromatographic fingerprints and the evaluation of the entire profiles provide an added value to the distinction, identification and quality control of the simultaneously investigated Artemisia species. Copyright © 2014 Elsevier B.V. All rights reserved.

7. Determination of triazine and chloroacetanilide herbicides in soils by microwave-assisted extraction (MAE) coupled to gas chromatographic analysis with either GC-NPD or GC-MS.

Science.gov (United States)

2002-08-28

A simple and rapid method based on microwave-assisted extraction (MAE) coupled to gas chromatographic analysis was developed for the analysis of triazine (atrazine, cyanazine, metribuzine, simazine and deethylatrazine, and deisopropylatrazine) and chloroacetanilide (acetochlor, alachlor, and metolachlor) herbicide residues in soils. Soil samples are processed by MAE for 5 min at 80 degrees C in the presence of acetonitrile (20 mL/sample). Mean recovery values of most solutes are >80% in the 10 to 500 microg/kg fortification range with respective RSDs (relative standard deviations) NPD) or a mass spectrometric detector (GC-MS).

8. Standardization of medfly trapping for use in sterile insect technique programmes. Final report of a co-ordinated research programme 1986-1992

International Nuclear Information System (INIS)

1996-05-01

As different trapping systems are often applied in different countries or regions, it becomes difficult to compare population data from these regions. Also, population measurements taken with the same trap but in different climates are again difficult to compare. Given the cosmopolitan nature of the medfly and the area-wide control programmes developed against it, it is necessary to be able to estimate or compare fly population levels even when measured with different traps and in different environments. In view of the above, the Joint FAO/IAEA Division, which has long been involved in medfly eradication and/or control activities in different regions, organized a co-ordinated research programme with the objective to compare and to standardize several of the most common medfly traps under different weather, host-tree and population density conditions. Tests were carried out in eight different countries and climates in northern Africa, southern Europe and Central America. Production of fruits preferred by the medfly is important in all eight countries. Refs, figs, tabs

9. Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity

International Nuclear Information System (INIS)

Nascimento, Martha do

1996-01-01

The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of β cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author)

10. Human reliability assessment in a 99Mo/99mTc generator production facility using the standardized plant analysis risk-human (SPAR-H) technique.

Science.gov (United States)

Eyvazlou, Meysam; Dadashpour Ahangar, Ali; Rahimi, Azin; Davarpanah, Mohammad Reza; Sayyahi, Seyed Soheil; Mohebali, Mehdi

2018-02-13

Reducing human error is an important factor for enhancing safety protocols in various industries. Hence, analysis of the likelihood of human error in nuclear industries such as radiopharmaceutical production facilities has become more essential. This cross-sectional descriptive study was conducted to quantify the probability of human errors in a 99 Mo/ 99m Tc generator production facility in Iran. First, through expert interviews, the production process of the 99 Mo/ 99m Tc generator was analyzed using hierarchical task analysis (HTA). The standardized plant analysis risk-human (SPAR-H) method was then applied in order to calculate the probability of human error. Twenty tasks were determined using HTA. All of the eight performance shaping factors (PSF S ) were evaluated for the tasks. The mean probability of human error was 0.320. The highest and the lowest probability of human error in the 99 Mo/ 99m Tc generator production process, related to the 'loading the generator with the molybdenum solution' task and the 'generator elution' task, were 0.858 and 0.059, respectively. Required measures for reducing the human error probability (HEP) were suggested. These measures were derived from the level of PSF S that were evaluated in this study.

11. Polyphenolic characterization and chromatographic methods for fast assessment of culinary Salvia species from South East Europe.

Science.gov (United States)

Cvetkovikj, I; Stefkov, G; Acevska, J; Stanoeva, J Petreska; Karapandzova, M; Stefova, M; Dimitrovska, A; Kulevanova, S

2013-03-22

Although the knowledge and use of several Salvia species (Salvia officinalis, Salvia fruticosa, and Salvia pomifera) can be dated back to Greek Era and have a long history of culinary and effective medicinal use, still there is a remarkable interest concerning their chemistry and especially the polyphenolic composition. Despite the demand in the food and pharmaceutical industry for methods for fast quality assessment of the herbs and spices, even now there are no official requirements for the minimum content of polyphenols in sage covered by current regulations neither the European Pharmacopoeia monographs nor the ISO 11165 standard. In this work a rapid analytical method for extraction, characterization and quantification of the major polyphenolic constituents in Sage was developed. Various extractions (infusion - IE; ultrasound-assisted extraction - USE and microwave-assisted extraction - MWE) were performed and evaluated for their effectiveness. Along with the optimization of the mass-detector and chromatographic parameters, the applicability of three different reverse C18 stationary phases (extra-density bonded, core-shell technology and monolith column) for polyphenolics characterization was evaluated. A comprehensive overview of the very variable polyphenolic composition of 118 different plant samples of 68 populations of wild growing culinary Salvia species (S. officinalis: 101; S. fruticosa: 15; S. pomifera: 2) collected from South East Europe (SEE) was performed using HPLC-DAD-ESI-MS(n) and more than 50 different compounds were identified and quantified. With this work the knowledge about polyphenols of culinary Sage was expanded thus the possibility for gaining an insight into the chemodiversity of culinary Salvia species in South East Europe was unlocked. Copyright © 2013 Elsevier B.V. All rights reserved.

12. Determination of phytochemicals, antioxidant activity and total phenolic content in Andrographis paniculata using chromatographic methods.

Science.gov (United States)

Kurzawa, Marzanna; Filipiak-Szok, Anna; Kłodzińska, Ewa; Szłyk, Edward

2015-07-15

Antioxidant activity, total phenolics content and selected phytochemicals (alkaloids and andrographolides) were determined in Andrographis paniculata and in dietary supplements containing this plant. Antioxidant activity was measured by FRAP, CUPRAC and DPPH procedures and ranged from 503.36 to 6164.09μmol TE/100g d.m. depending on methods, part of plant and kind of dietary supplement. The total phenolics (175.13-1723.79mg GAE/100g) and andrographolides content (19.44-85.13mg/g) in the studied samples were correlated with antioxidant activities determined by CUPRAC, FRAP and DPPH (r>0.95, p<0.05 level). Purine alkaloids: caffeine, theobromine, theophylline and indole alkaloids: harmine, harmane, harmol, yohimbine, brucine and strychnine were detected in the studied samples by different chromatographic techniques (HPLC-DAD, LC-MS/MS, GC-MS). The total alkaloids content in APs-roots and APs-leaves varies from 50.71±0.36mg/g d.m. to 78.71±0.48mg/g d.m., respectively, whereas for dietary supplements (Pn and DK) TAC was found between 19.52±0.15mg/g and 22.18±0.15mg/g d.m.. The highest concentration of andrographolides was found in A. paniculata leaves, whereas the lowest in dietary supplement Pn. Moreover principal component analysis, cluster analysis and one-way ANOVA follow by Duncan's tests were also performed. Copyright © 2015. Published by Elsevier B.V.

13. Extraction chromatographic separation of minor actinides from PUREX high-level wastes using CMPO

International Nuclear Information System (INIS)

Mathur, J.N.; Murali, M.S.; Iyer, R.H.; Ramanujam, A.; Dhami, P.S.; Gopalakrishnan, V.; Rao, M.K.; Badheka, L.P.; Banerji, A.

1995-01-01

An extraction chromatographic technique using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) adsorbed on chromosorb-102 (CAC) has been tested as an alternative to the TRUEX solvent extraction process, where CMPO has been used as the extracting agent to recover minor actinides from high-activity waste (HAW) solutions of PUREX origin. The batchwise uptake behavior of U(VI), Pu(IV), Am(III), Eu(III), Zr(IV), Fe(III), Ru(III), and TcO 4 - from a nitric acid medium by CAC has been studied. The uptake of actinides and lanthanides are higher than those of other fission products and inert materials. The batchwise loading experiments in the presence of Nd(III)/U(VI) have shown that at lower concentrations of these metal ions, the uptake of Pu(IV), U(VI), and Am(III) are reasonably high. Studies on loading of Nd(III), U(VI), and Pu(IV) on a column containing 1.7 g of CAC have shown that Nd(III) (30 mg) and U(VI) (90 mg) could be loaded, while Pu(IV) (∼0.6) was loaded on a small column containing 100 mg of CAC without any break-through. Further, a synthetic HAW solution as such and the actual PUREX HAW solution, after depleting the uranium content by a 30% tributyl-phosphate contact, were loaded on a CAC column. The effluents did not contain any alpha activity above the background level. The activities could subsequently be eluted with 0.0.4 M HNO 3 (americium and rare earths), 0.01 M oxalic acid (plutonium), and 0.25 M Na 2 CO 3 [U(VI)]. The recoveries of these metal ions were found to be >99%

14. Exploratory analysis of chromatographic fingerprints to distinguish rhizoma Chuanxiong and rhizoma Ligustici.

Science.gov (United States)

Alaerts, G; Merino-Arévalo, M; Dumarey, M; Dejaegher, B; Noppe, N; Matthijs, N; Smeyers-Verbeke, J; Vander Heyden, Y

2010-12-03

Identification and quality control of products of natural origin, used for preventive and therapeutical goals, is required by regulating authorities, as the World Health Organization. This study focuses on the identification and distinction of the rhizomes from two Chinese herbs, rhizoma Chuanxiong (from Ligusticum chuanxiong Hort.) and rhizoma Ligustici (from Ligusticum jeholense Nakai et Kitag), by chromatographic fingerprints. A second goal is using the fingerprints to assay ferulic acid, as its concentration provides an additional differentiation feature. Several extraction methods were tested, to obtain the highest number of peaks in the fingerprints. The best results were found using 76:19:5 (v/v/v) methanol/water/formic acid as solvent and extracting the pulverized material on a shaking bath for 15 min. Then fingerprint optimization was done. Most information about the herbs, i.e. the highest number of peaks, was observed on a Hypersil ODS column (250 mm × 4.6 mm ID, 5 μm), 1.0% acetic acid in the mobile phase and employing within 50 min linear gradient elution from 5:95 (v/v) to 95:5 (v/v) acetonitrile/water. The final fingerprints were able to distinguish rhizoma Chuanxiong and Ligustici, based on correlation coefficients combined with exploratory data analysis. The distinction was visualized using Principal Component Analysis, Projection Pursuit and Hierarchical Clustering Analysis techniques. Quantification of ferulic acid was possible in the fingerprints of both rhizomes. The time-different intermediate precisions of the fingerprints and of the ferulic acid quantification were shown to be acceptable. Copyright © 2010 Elsevier B.V. All rights reserved.

15. An in vitro comparison of quantitative percussion diagnostics with a standard technique for determining the presence of cracks in natural teeth.

Science.gov (United States)

Sheets, Cherilyn G; Stewart, Devin L; Wu, Jean C; Earthman, James C

2014-08-01

The detection of cracks and fractures in natural teeth is a diagnostic challenge. Cracks are often not visible clinically nor detectable in radiographs. The purpose of this study was to evaluate the diagnostic parity of quantitative percussion diagnostics, transillumination, clinical microscopy, and dye penetration. Three independent examiners provided blind testing for the study. Examiner 1 transilluminated 30 extracted teeth and 23 three-dimensional copy replica control teeth and documented any visible cracks. Each tooth was then mounted in acrylic resin with a periodontal ligament substitute. Examiner 2 examined each specimen aided by the clinical microscope and transillumination and documented visible tooth cracks and fractures. Examiners 1 and 3 then independently tested all specimens with a device developed for quantitative percussion diagnostics. All visible cracks/fractures were removed with a water-cooled fine diamond rotary instrument. Crack visibility was enhanced by the use of a clinical microscope, dye penetrant, and accessory transillumination. This disassembly process was video documented/photographed for each specimen. One more quantitative percussion diagnostics testing was administered when the disassembly was complete. Quantitative percussion diagnostics crack detection agreed with the gold standard microscope and transillumination method in 52 of 53 comparisons (98% agreement). Moreover, the method achieved 96% specificity and 100% sensitivity for detecting cracks and fractures in natural teeth. When all tooth cracks were removed, quantitative percussion diagnostics indicated no further structural instability. Quantitative percussion diagnostics can nondestructively detect cracks and fractures in natural teeth with accuracy similar to that of the clinical microscope, transillumination, and dye penetrant. In addition, the method was able to reveal the presence of many cracks that were not detected by conventional transillumination. Copyright

16. Evaluation of a Net Dose-Reducing Organ-Based Tube Current Modulation Technique: Comparison With Standard Dose and Bismuth-Shielded Acquisitions.

Science.gov (United States)

Lambert, Jack W; Gould, Robert G

2016-06-01

The purpose of this study was to compare the dose and image noise associated with two methods of radiation dose reduction to the superficial anterior organs: bismuth shielding and a net dose-reducing organ-based tube current modulation TCM technique. Three scanning modes-the reference dose, bismuth-shielded, and organ dose-modulated modes-were evaluated. With the use of an anthropomorphic phantom, surface doses to the eye, thyroid, and female breast were measured using optically stimulated luminescence detectors. A CT dose index (CTDI) phantom was used to compare doses with the overall phantom volume in the different modes. The dose to the anterior surface was reduced by 35%, 42%, and 37% in the head, neck, and chest regions, respectively, when the bismuth-shielded scanning mode was used, whereas surface dose reductions of 20%, 34%, and 38%, respectively, were noted for the organ-based TCM scanning mode. The CTDI-type dose was reduced by 13%, 14%, and 17% in the head, neck, and chest regions, respectively, when the bismuth-shielded mode was used, whereas dose reductions of 9%, 18%, and 20%, respectively, were observed for the organ-based TCM mode. Anterior image noise increased by 0.1, 9.5, and 0.7 HU in the head, neck, and chest regions, respectively, when the bismuth-shielded mode was used. These findings compared with increases in image noise of 0.1, 0.5, and 0.6 HU, respectively, for the organ-based TCM mode. The implementation of organ-based TCM reduces the net tube current per rotation, so no body region receives increased radiation exposure. The use of this method allows the dose to the anterior surface to be reduced to an extent similar to that observed with the use of the bismuth shield, yet it does not produce the image quality degradation associated with bismuth shielding.

17. New liquid chromatographic-chemometric approach for the determination of sunset yellow and tartrazine in commercial preparation.

Science.gov (United States)

Dinç, Erdal; Aktaş, A Hakan; Ustündağ, Ozgür

2005-01-01

A new liquid chromatographic (LC)-chemometric approach was developed for the determination of sunset yellow (SUN) and tartrazine (TAR) in commercial preparations. This approach uses LC and chemometric calibration methods, i.e., classical least-squares (CLS), principal component regression (PCR), and partial-least squares (PLS), simultaneously. The combined LC-chemometric approaches, denoted as LC-CLS, LC-PCR, and LC-PLS, are based on photodiode array (PDA) detection at multiple wavelengths. Optimum chromatographic separation of SUN and TAR with allura red as the internal standard (IS) was obtained by using a Waters Symmetry C18 column, 5 microm, 4.6 x 250 mm, and 0.2 M acetate buffer (pH 5)-acetonitrile-methano-bidistilled water (55 + 20 + 15 + 10, v/v) as the mobile phase at a flow rate of 1.9 mL/min. The LC data sets consisting of the ratios of analyte peak areas to the IS peak area were obtained by using PDA detection at 5 wavelengths (465, 470, 475, 480, and 485 nm). LC-chemometric calibrations for SUN and TAR were separately constructed by using the relationship between the peak-area ratio and the training sets for each colorant. LC-chemometric approaches were tested for different synthetic mixtures containing SUN and TAR in the presence of the IS. These LC-chemometric calibrations were applied to a commercial preparation of the 2 colorants. The experimental results of the LC-chemometric approaches were compared with those obtained by a developed classical LC method using single-wavelength detection.

18. Rapid, sensitive liquid chromatographic method for determination of zearalenone and alpha- and beta-zearalenol in wheat.

Science.gov (United States)

Trenholm, H L; Warner, R M; Fitzpatrick, D W

1984-01-01

A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and alpha- and beta-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanol-chloroform (2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and alpha-zearalenol standards on the fluorescence detector and 4 ng for beta-zearalenol on the UV detector, which is equivalent to 20 micrograms zearalenone and 20 micrograms alpha-zearalenol/kg, and 160 micrograms beta-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and alpha-zearalenol on the fluorescence detector and 0-50 ng beta-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).

19. A review on sample preparation and chromatographic determination of acephate and methamidophos in

Directory of Open Access Journals (Sweden)

Vijay Kumar

2015-09-01

Full Text Available Acephate and its metabolite methamidophos are common organophosphorus insecticide used for crop protection. High uses of acephate and methamidophos have induced health issues and environmental pollution. Their undesired presence in the environment is creating ecotoxicology and may harm human health. It is therefore essential to detect the presence of acephate and methamidophos even in trace level. In this review, we have tried to accommodate successful methods of detection of acephate and methamidophos in the different biological media. Their recovery and residue analysis in different media such as vegetables, human and animal tissues have also included. The most common method for their determination is based on chromatographic separation and identification. Among different chromatographic methods, LC and GC coupled with different detectors have used. But, they both need extensive pretreatment and cleanup procedure, before undergoing chromatographic separation and identification. LC coupled with mass spectrometry (LCMS is sometime able to detect acephate and methamidophos in ppm level.

20. Research on technology of online gas chromatograph for SF6 decomposition products

Science.gov (United States)

Li, L.; Fan, X. P.; Zhou, Y. Y.; Tang, N.; Zou, Z. L.; Liu, M. Z.; Huang, G. J.

2017-12-01

Sulfur hexafluoride (SF6) decomposition products were qualitatively and quantitatively analyzed by several gas chromatographs in the laboratory. Test conditions and methods were selected and optimized to minimize and eliminate the SF6’ influences on detection of other trace components. The effective separation and detection of selected characteristic gases were achieved. And by comparison among different types of gas chromatograph, it was found that GPTR-S101 can effectively separate and detect SF6 decomposition products and has best the best detection limit and sensitivity. On the basis of GPTR-S101, online gas chromatograph for SF6decomposition products (GPTR-S201) was developed. It lays the foundation for further online monitoring and diagnosis of SF6.

1. In-line gas chromatographic apparatus for measuring the hydrophobic micropore volume (HMV) and contaminant transformation in mineral micropores.

Science.gov (United States)

Cheng, Hefa; Reinhard, Martin

2010-07-15

Desorption of hydrophobic organic compounds from micropores is characteristically slow compared to surface adsorption and partitioning. The slow-desorbing mass of a hydrophobic probe molecule can be used to calculate the hydrophobic micropore volume (HMV) of microporous solids. A gas chromatographic apparatus is described that allows characterization of the sorbed mass with respect to the desorption rate. The method is demonstrated using a dealuminated zeolite and an aquifer sand as the model and reference sorbents, respectively, and trichloroethylene (TCE) as the probe molecule. A glass column packed with the microporous sorbent is coupled directly to a gas chromatograph that is equipped with flame ionization and electron capture detectors. Sorption and desorption of TCE on the sorbent was measured by sampling the influent and effluent of the column using a combination of switching and injection valves. For geosorbents, the HMV is quantified based on Gurvitsch's rule from the mass of TCE desorbed at a rate that is characteristic for micropores. Instrumental requirements, design considerations, hardware details, detector calibration, performance, and data analysis are discussed along with applications. The method is novel and complements traditional vacuum gravimetric and piezometric techniques, which quantify the total pore volume under vacuum conditions. The HMV is more relevant than the total micropore volume for predicting the fate and transport of organic contaminants in the subsurface. Sorption in hydrophobic micropores strongly impacts the mobility of organic contaminants, and their chemical and biological transformations. The apparatus can serve as a tool for characterizing microporous solids and investigating contaminant-solid interactions. 2010 Elsevier B.V. All rights reserved.

2. Proton radiation therapy (prt) for pediatric optic pathway gliomas: comparison with 3d planned conventional photons and a standard photon technique

International Nuclear Information System (INIS)

Fuss, Martin; Hug, Eugen B.; Schaefer, Rosemary A.; Nevinny-Stickel, Meinhard; Miller, Daniel W.; Slater, James M.; Slater, Jerry D.

1999-01-01

Purpose: Following adequate therapy, excellent long-term survival rates can be achieved for patients with optic pathway gliomas. Therefore, avoidance of treatment-related functional long-term sequelae is of utmost importance. Optimized sparing of normal tissue is of primary concern in the development of new treatment modalities. The present study compares proton radiation therapy (PRT) with a three-dimensional (3D)-planned multiport photon and a lateral beam photon technique for localized and extensive optic pathway tumors. Methods and Materials: Between February 1992 and November 1997, seven children with optic pathway gliomas underwent PRT. For this study, we computed proton, 3D photon, and lateral photon plans based on the same CT data sets, and using the same treatment planning software for all plans. Radiation exposure for normal tissue and discrete organs at risk was quantified based on dose-volume histograms. Results: Gross tumor volume (GTV) ranged from 3.9 cm 3 to 127.2 cm 3 . Conformity index (relation of encompassing isodose to GTV volume) was 2.3 for protons, 2.9 for 3D photons, and 7.3 for lateral photons. The relative increase of normal tissue (NT) encompassed at several isodose levels in relation to NT encompassed by the 95% proton isodose volume was computed. Relative NT volume of proton plan isodoses at the 95%, 90%, 80%, 50%, and 25% isodose level increased from 1 to 1.6, 2.8, 6.4, to a maximum of 13.3. Relative volumes for 3D photons were 1.6, 2.4, 3.8, 11.5, and 34.8. Lateral plan relative values were 6, 8.3, 11.5, 19.2, and 26.8. Analysis for small ( 3 ) and larger (> 80 cm 3 ) tumors showed that protons encompassed the smallest volumes of NT at all isodose levels. Comparable conformity and high-dose gradient were achieved for proton and 3D photon plans in small tumors. However, with increasing tumor volume and complexity, differences became larger. At the 50% isodose level, 3D photons were superior to lateral photons for small tumors; this

3. Test plan for demonstrating plutonium extraction from 10-L solutions using EIChrom extraction chromatographic resins

International Nuclear Information System (INIS)

Barney, G.S.

1994-01-01

Corrosive plutonium solutions stored in 10-L containers at the Plutonium Finishing Plant must be treated to convert the plutonium to a safe, solid form for storage and to remove the americium so that radiation exposure can be reduced. Extraction chromatographic resins will be tested for separating plutonium from these solutions in the laboratory. Separation parameters will be developed during the testing for large scale processing of the 10-L solutions and solutions of similar composition. Use of chromatographic resins will allow plutonium separation with minimum of chemical addition to the feed and without the need for plutonium valence adjustment. The separated plutonium will be calcined to plutonium oxide by direct solution calcination

4. Use of laminar chromatographic methods for determination of separation conditions in column extraction chromatography

International Nuclear Information System (INIS)

Ghersini, G.; Cerrai, E.

1978-01-01

Possibilities of using laminar chromatographic methods (paper and thin-layer chromatography) to determine optimal separation conditions in column extraction chromatography are analysed. Most of the given laminar methods are presented as Rf-spectra, i.e. as dependences of Rf found experimentally on eluating solution component concentration. Interrelation between Rf and distribution coefficients of corresponding liquid extraction systems and retention volumes of chromatographic columns is considered. Literature data on extraction paper and thin-layer chromatography of elements with various immovable phases are presented

5. Two dimensional chromatographic analysis as a quality measure of ...

African Journals Online (AJOL)

Thin layer chromatography has been used extensively to determine the quality of plant extracts and could just as readily be applied to the assessment of quality of homoeopathic mother tinctures. The development of a multidimensional technique allows for greater quality analyses of these extracts. Materials and Methods: ...

6. Technique to associate IMRT and a cervical-sus-clavicular standard beam for the irradiation of ENT cancers; Technique d'association d'une RCMI et d'un faisceau cervico-susclaviculaire standard pour l'irradiation des cancers ORL

Energy Technology Data Exchange (ETDEWEB)

Beneyton, V.; Balosso, J. [Universite joseph-Fourier, Grenoble (France); Dusserre, A.; Sihanath, R.; Reboulet, G.; Gabelle-Flandin, I.; Pasteris, C.; Villa, J.; Tessier, A.; Giraud, J.Y. [CHU de Grenoble, Grenoble (France)

2011-10-15

Intensity-modulated conformational radiotherapy allows dose distribution optimization and sane tissue sparing, and even dose escalation. It is performed within a unique volume and requires specific instrumentation and quality control. In ENT, the tumour bed and ganglionary areas represent all together a too large volume for the available instrumentation. Thus, the author presents an hybrid technique using intensity modulation and a cervical-sus-clavicular beam with unique iso-centre and mobile junction. This technique results in a reduced volume to be treated and an easier quality control. They report the application to five patients. The session duration is also reduced without altering IMRT qualities for the main volume. Short communication

7. Chromatographic analysis of irradiated medicinal herbs: Rhamnus purshiana D.C. and Paulinia cupana Kunth

International Nuclear Information System (INIS)

Koseki, Paula M; Rela, Paulo R.; Villavicencio, Anna Lucia C.H.

2001-01-01

8. TBP degradation products. Separation and gas-chromatographic determination

International Nuclear Information System (INIS)

Kuada, T.A.; Alem, C.M.; Matsuda, H.T.; Araujo, B.F. de; Araujo, J.A de.

1991-11-01

A separation method for di butylphosphate, mono butylphosphate and phosphoric acid as degradation products in organic and aqueous streams of the process containing variable amounts of actinides and fission products is described. The products were separated by extraction and after methylation the final determination was carried out by gas chromatography. TPP was used as internal standard and 5 to 500 mg/L concentration range was determined with 1 to 10% deviation depending on the concentration of organo phosphates. (author)

9. [Application of robustness test for assessment of the measurement uncertainty at the end of development phase of a chromatographic method for quantification of water-soluble vitamins].

Science.gov (United States)

Ihssane, B; Bouchafra, H; El Karbane, M; Azougagh, M; Saffaj, T

2016-05-01

We propose in this work an efficient way to evaluate the measurement of uncertainty at the end of the development step of an analytical method, since this assessment provides an indication of the performance of the optimization process. The estimation of the uncertainty is done through a robustness test by applying a Placquett-Burman design, investigating six parameters influencing the simultaneous chromatographic assay of five water-soluble vitamins. The estimated effects of the variation of each parameter are translated into standard uncertainty value at each concentration level. The values obtained of the relative uncertainty do not exceed the acceptance limit of 5%, showing that the procedure development was well done. In addition, a statistical comparison conducted to compare standard uncertainty after the development stage and those of the validation step indicates that the estimated uncertainty are equivalent. The results obtained show clearly the performance and capacity of the chromatographic method to simultaneously assay the five vitamins and suitability for use in routine application. Copyright © 2015 Académie Nationale de Pharmacie. Published by Elsevier Masson SAS. All rights reserved.

10. Determination of bitter orange alkaloids in dietary supplement Standard Reference Materials by liquid chromatography with atmospheric-pressure ionization mass spectrometry.

Science.gov (United States)

Putzbach, Karsten; Rimmer, Catherine A; Sharpless, Katherine E; Wise, Stephen A; Sander, Lane C

2007-09-01

A liquid chromatographic atmospheric-pressure ionization electrospray mass spectrometry (LC-API-ES-MS) method has been developed for the determination of five bitter orange alkaloids (synephrine, octopamine, n-methyltyramine, tyramine, and hordenine) in bitter orange-containing dietary supplement standard reference materials (SRMs). The materials represent a variety of natural, extracted, and processed sample matrices. Two extraction techniques were evaluated: pressurized-fluid extraction (PFE) and sonication extraction. The influence of different solvents, extraction temperatures, and pH were investigated for a plant material and a processed sample. The LC method uses a new approach for the separation of highly polar alkaloids. A fluorinated, silica-based stationary phase separated the five alkaloids and the internal standard terbutaline in less than 20 min. This method enabled the determination of the dominant alkaloid synephrine and other minor alkaloids in a variety of dietary supplement SRMs.

11. An integrated methodological approach to the computer-assisted gas chromatographic screening of basic drugs in biological fluids using nitrogen selective detection.

Science.gov (United States)

Dugal, R; Massé, R; Sanchez, G; Bertrand, M J

1980-01-01

This paper presents the methodological aspects of a computerized system for the gas-chromatographic screening and primary identification of central nervous system stimulants and narcotic analgesics (including some of their respective metabolites) extracted from urine. The operating conditions of a selective nitrogen detector for optimized analytical functions are discussed, particularly the effect of carrier and fuel gas on the detector's sensitivity to nitrogen-containing molecules and discriminating performance toward biological matrix interferences. Application of simple extraction techniques, combined with rapid derivatization procedures, computer data acquisition, and reduction of chromatographic data are presented. Results show that this system approach allows for the screening of several drugs and their metabolites in a short amount of time. The reliability and stability of the system have been tested by analyzing several thousand samples for doping control at major international sporting events and for monitoring drug intake in addicts participating in a rehabilitation program. Results indicate that these techniques can be used and adapted to many different analytical toxicology situations.

12. Maximizing Chromatographic Information from Environmental Extracts by GCxGC-ToF-MS

NARCIS (Netherlands)

Skoczynska, E.M.; Korytar, P.; Boer, de J.

2008-01-01

Comprehensive two-dimensional gas chromatography (GCxGC) coupled with a time-of-flight (ToF) detector allows the separation of many constituents of previously unresolved complex mixtures (UCM) of contaminants in sediment samples. In addition to the powerful chromatographic resolution, automated mass

13. [Sample preparation methods for chromatographic analysis of organic components in atmospheric particulate matter].

Science.gov (United States)

Hao, Liang; Wu, Dapeng; Guan, Yafeng

2014-09-01

The determination of organic composition in atmospheric particulate matter (PM) is of great importance in understanding how PM affects human health, environment, climate, and ecosystem. Organic components are also the scientific basis for emission source tracking, PM regulation and risk management. Therefore, the molecular characterization of the organic fraction of PM has become one of the priority research issues in the field of environmental analysis. Due to the extreme complexity of PM samples, chromatographic methods have been the chief selection. The common procedure for the analysis of organic components in PM includes several steps: sample collection on the fiber filters, sample preparation (transform the sample into a form suitable for chromatographic analysis), analysis by chromatographic methods. Among these steps, the sample preparation methods will largely determine the throughput and the data quality. Solvent extraction methods followed by sample pretreatment (e. g. pre-separation, derivatization, pre-concentration) have long been used for PM sample analysis, and thermal desorption methods have also mainly focused on the non-polar organic component analysis in PM. In this paper, the sample preparation methods prior to chromatographic analysis of organic components in PM are reviewed comprehensively, and the corresponding merits and limitations of each method are also briefly discussed.

14. Gas-chromatographic quantitative determination of argon in air samples, by elimination of oxigen

International Nuclear Information System (INIS)

Sofronie, E.

1982-08-01

A method of gas-chromatographic quantitative determination of argon in air samples, by elimination of oxygen, is presented. Experiments were carried out in a static system. Conditions for the application of the method in dynamic systems are specified. Sensibility of the method: 5 10 -4 cm 3 Ar per cm 3 of air. (author)

15. High Performance Liquid Chromatographic Analysis of Phytoplankton Pigments Using a C16-Amide Column

Science.gov (United States)

A reverse-phase high performance liquid chromatographic (RP-HPLC) method was developed to analyze in a single run, most polar and non-polar chlorophylls and carotenoids from marine phytoplankton. The method is based on a RP-C16-Amide column and a ternary gradient system consistin...

16. Using Aspen to Teach Chromatographic Bioprocessing: A Case Study in Weak Partitioning Chromatography for Biotechnology Applications

Science.gov (United States)

Evans, Steven T.; Huang, Xinqun; Cramer, Steven M.

2010-01-01

The commercial simulator Aspen Chromatography was employed to study and optimize an important new industrial separation process, weak partitioning chromatography. This case study on antibody purification was implemented in a chromatographic separations course. Parametric simulations were performed to investigate the effect of operating parameters…

17. Vanadium speciation by chromatographic separation of V(IV) and V ...

African Journals Online (AJOL)

A new method for vanadium speciation has been developed. The method is based on chromatographic separation of vanadium(IV) and vanadium(V) in acidic medium followed by the determination with ICP-OES. Vanadium species exist in acidic solution (pH < 3) as VO2+ for vanadium(IV) and VO2 + for vanadium(V).

18. Performance characteristics of methods of analysis used for regulatory purposes. I. Drug dosage forms. B. Gas chromatographic methods.

Science.gov (United States)

Horwitz, W; Albert, R

1984-01-01

Gas chromatographic methods for the analysis of drug dosage forms consist of a simple extraction, dilution with an internal standard solution, and injection, or, even simpler, dilution with the internal standard solution and injection. These methods were used in 7 collaborative studies of the determination of 12 pharmaceuticals, published in the Journal of the AOAC during 1973-1983. A total of 43 individual materials consisting of various dosage forms were each analyzed, usually in duplicate, by an average of 8 laboratories, with a total of 582 reported determinations. The average within-laboratory coefficient of variation (CVo) was 1.25% and the average among-laboratories coefficient of variation (CVx) was 2.41%, for a CVo/CVx ratio of 0.52, at an average outlier rate of 1.4% of the reported values. The line of best fit for CVx plotted against concentration increases with decreasing concentration, extending from a CVx of approximately 1.8% at 100% concentration to a CVx of approximately 3.2% at 1% concentration. The change in CVx for a 10-fold decrease in concentration is approximately 0.7% CVx, independent of analyte and matrix.

19. Gas chromatographic-thermal energy analysis method for N-nitrosodibutylamine in latex infant pacifiers: collaborative study

Energy Technology Data Exchange (ETDEWEB)

Each of 5 collaborating laboratories determined volatile N-nitrosamines in 3 blind quadruplicate sets of latex rubber infant pacifier samples, using a gas chromatographic-thermal energy analysis (GC-TEA) method. Volatile N-nitrosamines are extracted from cut-up pacifier nipples with CH/sub 2/Cl/sub 2/. The extract is concentrated and subjected to high temperature purge and trap, and the nitrosamines are eluted from the trap and determined by GC-TEA. N-Nitrosodibutylamine (NDBA) was the only nitrosamine found in sufficient concentration to allow analysis. NDBA concentrations of the 3 sets of samples were 82.6, 21.0, and 7.12 ng/g rubber. The repeatability relative standard deviations ranged from 7.46 to 24.0% and the reproducibility relative standard deviations from 7.46 to 29.2%. The minimum detectable level of NDBA by this method is 3.6 ng/g rubber. The method has been adopted official first action.

20. Interlaboratory tests to identify irradiation treatment of various foods via gas chromatographic detection of hydrocarbons, ESR spectroscopy and TL analysis

International Nuclear Information System (INIS)

Schreiber, G.A.; Helle, N.; Schulzki, G.; Linke, B.; Spiegelberg, A.; Mager, M.; Boegl, K.W.

1996-01-01

The gas chromatographic (GC) analysis of radiation-induced volatile hydrocarbons (HC) and 2-alkylcyclobutanones, the ESR spectroscopic detection of radiation-specific radicals and the thermoluminescence (TL) analysis of silicate mineral are the most important methods for identification of irradiated foods. After successful performance in interlaboratory studies on meat products, fish, spices, herbs and shells of nuts, all or some of these methods have been approved by national authorities in Germany and the United Kingdom. Recently, draft European Standards have been elaborated for approval by member states of the European Committee for Standardization (CEN). Several research laboratories have shown that these methods can be applied to various foods not yet tested in collaborative studies. However, for an effective application in food control it is necessary to prove their suitability in interlaboratory studies. Therefore, in 1993/94, various interlaboratory tests were organised by the BgVV. In an ESR spectroscopic test, shrimps and paprika powder were examined. Shrimps were also the subject of examination in a TL test. Finally, GC detection of radiation-induced hydrocarbons in the fat fraction of foods was used in another test to identify irradiated Camembert, avocado, papaya and mango. In the following paper, results of the interlaboratory tests are summarised. Detailed reports are published by this institute. (author)

1. Interlaboratory tests to identify irradiation treatment of various foods via gas chromatographic detection of hydrocarbons, ESR spectroscopy and TL analysis

Energy Technology Data Exchange (ETDEWEB)

Schreiber, G.A.; Helle, N.; Schulzki, G.; Linke, B.; Spiegelberg, A.; Mager, M.; Boegl, K.W. [BgVV - Federal Inst. for Health Protection of Consumers and Veterinary Medicine, Berlin (Germany)

1996-12-31

The gas chromatographic (GC) analysis of radiation-induced volatile hydrocarbons (HC) and 2-alkylcyclobutanones, the ESR spectroscopic detection of radiation-specific radicals and the thermoluminescence (TL) analysis of silicate mineral are the most important methods for identification of irradiated foods. After successful performance in interlaboratory studies on meat products, fish, spices, herbs and shells of nuts, all or some of these methods have been approved by national authorities in Germany and the United Kingdom. Recently, draft European Standards have been elaborated for approval by member states of the European Committee for Standardization (CEN). Several research laboratories have shown that these methods can be applied to various foods not yet tested in collaborative studies. However, for an effective application in food control it is necessary to prove their suitability in interlaboratory studies. Therefore, in 1993/94, various interlaboratory tests were organised by the BgVV. In an ESR spectroscopic test, shrimps and paprika powder were examined. Shrimps were also the subject of examination in a TL test. Finally, GC detection of radiation-induced hydrocarbons in the fat fraction of foods was used in another test to identify irradiated Camembert, avocado, papaya and mango. In the following paper, results of the interlaboratory tests are summarised. Detailed reports are published by this institute. (author).

2. Video Coding Technique using MPEG Compression Standards

African Journals Online (AJOL)

Akorede

multimedia communication and storage. Technologies such as mobile video, mobile TV, DTV, DVD players, digital cameras, video telephony and multimedia messaging have all been enabled through the availability of efficient compression algorithms. Photographs, printed text, and other hard copy media are now routinely ...

3. Multivariate curve resolution of incomplete fused multiset data from chromatographic and spectrophotometric analyses for drug photostability studies

Energy Technology Data Exchange (ETDEWEB)

Luca, Michele De, E-mail: michele.deluca@unical.it [Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via P. Bucci, Rende, CS 87036 (Italy); Ragno, Gaetano; Ioele, Giuseppina [Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Via P. Bucci, Rende, CS 87036 (Italy); Tauler, Romà [Department of Environmental Chemistry, IDAEA-CSIC, C/Jordi Girona, 18-26, Barcelona 08034 (Spain)

2014-07-21

Highlights: • A new MCR-ALS algorithm is proposed for the analysis of incomplete fused multiset. • Resolution of the data allowed the description of amiloride kinetic photodegradation. • The new MCR-ALS algorithm can be easily applied to other drugs and chemicals. - Abstract: An advanced and powerful chemometric approach is proposed for the analysis of incomplete multiset data obtained by fusion of hyphenated liquid chromatographic DAD/MS data with UV spectrophotometric data from acid–base titration and kinetic degradation experiments. Column- and row-wise augmented data blocks were combined and simultaneously processed by means of a new version of the multivariate curve resolution-alternating least squares (MCR-ALS) technique, including the simultaneous analysis of incomplete multiset data from different instrumental techniques. The proposed procedure was applied to the detailed study of the kinetic photodegradation process of the amiloride (AML) drug. All chemical species involved in the degradation and equilibrium reactions were resolved and the pH dependent kinetic pathway described.

4. Multivariate curve resolution of incomplete fused multiset data from chromatographic and spectrophotometric analyses for drug photostability studies

International Nuclear Information System (INIS)

Luca, Michele De; Ragno, Gaetano; Ioele, Giuseppina; Tauler, Romà

2014-01-01

Highlights: • A new MCR-ALS algorithm is proposed for the analysis of incomplete fused multiset. • Resolution of the data allowed the description of amiloride kinetic photodegradation. • The new MCR-ALS algorithm can be easily applied to other drugs and chemicals. - Abstract: An advanced and powerful chemometric approach is proposed for the analysis of incomplete multiset data obtained by fusion of hyphenated liquid chromatographic DAD/MS data with UV spectrophotometric data from acid–base titration and kinetic degradation experiments. Column- and row-wise augmented data blocks were combined and simultaneously processed by means of a new version of the multivariate curve resolution-alternating least squares (MCR-ALS) technique, including the simultaneous analysis of incomplete multiset data from different instrumental techniques. The proposed procedure was applied to the detailed study of the kinetic photodegradation process of the amiloride (AML) drug. All chemical species involved in the degradation and equilibrium reactions were resolved and the pH dependent kinetic pathway described

5. Fast gas chromatographic residue analysis in animal feed using split injection and atmospheric pressure chemical ionisation tandem mass spectrometry.

Science.gov (United States)

Tienstra, M; Portolés, T; Hernández, F; Mol, J G J

2015-11-27

Significant speed improvement for instrumental runtime would make GC–MS much more attractive for determination of pesticides and contaminants and as complementary technique to LC–MS. This was the trigger to develop a fast method (time between injections less than 10 min) for the determination of pesticides and PCBs that are not (or less) amenable to LC–MS. A key factor in achieving shorter analysis time was the use of split injection (1:10) which allowed the use of a much higher initial GC oven temperature. A shorter column (15 m), higher temperature ramp, and higher carrier gas flow rate (6 mL/min) further contributed to analysis-time reduction. Chromatographic resolution was slightly compromised but still well fit-for-purpose. Due to the high sensitivity of the technique used (GC–APCI-triple quadrupole MS/MS), quantification and identification were still possible down to the 10 μg/kg level, which was demonstrated by successful validation of the method for complex feed matrices according to EU guidelines. Other advantages of the method included a better compatibility of acetonitrile extracts (e.g. QuEChERS) with GC, and a reduced transfer of co-extractants into the GC column and mass spectrometer.

6. The chromatographic separation of particles using optical electric fields

DEFF Research Database (Denmark)

Javier Alvarez, Nicolas; Jeppesen, Claus; Yvind, Kresten

2013-01-01

We introduce a new field-flow fractionation (FFF) technique, whereby molecules are separated based on their differential interaction (dielectrophoresis (DEP)) with optical electric fields, i.e. electric fields with frequencies in the visible and near-infrared range. The results show that a parallel...... array of axially non-uniform optical fields yielding an attractive potential (positive-DEP-FFF) is advantageous for the separation of polymers, biomolecules, and nanoparticles over very short distances. Furthermore, positive-DEP-FFF yields superior selectivity and resolution compared to conventional...

7. Evaluation of selectivity in homologous multimodal chromatographic systems using in silico designed antibody fragment libraries.

Science.gov (United States)

Karkov, Hanne Sophie; Woo, James; Krogh, Berit Olsen; Ahmadian, Haleh; Cramer, Steven M

2015-12-24

This study describes the in silico design, surface property analyses, production and chromatographic evaluations of a diverse set of antibody Fab fragment variants. Based on previous findings, we hypothesized that the complementarity-determining regions (CDRs) constitute important binding sites for multimodal chromatographic ligands. Given that antibodies are highly diversified molecules and in particular the CDRs, we set out to examine the generality of this result. For this purpose, four different Fab fragments with different CDRs and/or framework regions of the variable domains were identified and related variants were designed in silico. The four Fab variant libraries were subsequently generated by site-directed mutagenesis and produced by recombinant expression and affinity purification to enable examination of their chromatographic retention behavior. The effects of geometric re-arrangement of the functional moieties on the multimodal resin ligands were also investigated with respect to Fab variant retention profiles by comparing two commercially available multimodal cation-exchange ligands, Capto MMC and Nuvia cPrime, and two novel multimodal ligand prototypes. Interestingly, the chromatographic data demonstrated distinct selectivity trends between the four Fab variant libraries. For three of the Fab libraries, the CDR regions appeared as major binding sites for all multimodal ligands. In contrast, the fourth Fab library displayed a distinctly different chromatographic behavior, where Nuvia cPrime and related multimodal ligand prototypes provided markedly improved selectivity over Capto MMC. Clearly, the results illustrate that the discriminating power of multimodal ligands differs between different Fab fragments. The results are promising indications that multimodal chromatography using the appropriate multimodal ligands can be employed in downstream bioprocessing for challenging selective separation of product related variants. Copyright © 2015 Elsevier B

8. High-speed counter-current chromatographic separation of phytosterols.

Science.gov (United States)

Schröder, Markus; Vetter, Walter

2011-07-01

Phytosterols are bioactive compounds which occur in low concentrations in plant oils. Due to their beneficial effects on human health, phytosterols have already been supplemented to food. Commercial phytosterol standards show insufficient purity and/or are very expensive. In this study, we developed a high-speed counter-current chromatography (HSCCC) method for the fractionation and analysis of a commercial crude β-sitosterol standard (purity ∼60% according to supplier). Different solvent systems were tested in shake-flask experiments, and the system n-hexane/methanol/aqueous silver nitrate solution (34/24/1, v/v/v) was finally used for HSCCC fractionation. About 50 mg phytosterols was injected and distributed into 57 fractions. Selected fractions were condensed and re-injected into the HSCCC system. This measure provided pure sitostanol (>99%) and β-sitosterol (∼99%), as well as a mixture of campesterol and stigmasterol without further phytosterols. An enriched HSCCC fraction facilitated the mass spectrometric analysis of further 11 minor phytosterols (after trimethylsilylation). It was also shown that the commercial product contained about 0.3% carotinoids which eluted without delay into an early HSCCC fraction and which were separated from the phytosterols.

9. Manual of Standard Operating Procedures for Veterinary Drug Residue Analysis (French Edition)

International Nuclear Information System (INIS)

2017-01-01

Laboratories are crucial to national veterinary drug residue monitoring programmes. However, one of the main challenges laboratories encounter is obtaining access to relevant methods of analysis. Thus, in addition to training, providing technical advice and transferring technology, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has resolved to develop clear and practical manuals to support Member State laboratories. The Coordinated Research Project (CRP) on Development of Radiometric and Allied Analytical Methods to Strengthen Residue Control Programs for Antibiotic and Anthelmintic Veterinary Drug Residues has developed a number of analytical methods as standard operating procedures (SOPs), which are now compiled here. This publication contains SOPs on chromatographic and spectrometric techniques, as well as radioimmunoassay and associated screening techniques, for various anthelmintic and antimicrobial veterinary drug residue analysis. Some analytical method validation protocols are also included. The publication is primarily aimed at food and environmental safety laboratories involved in testing veterinary drug residues, including under organized national residue monitoring programmes. It is expected to enhance laboratory capacity building and competence through the use of radiometric and complementary tools and techniques. The publication is also relevant for applied research on residues of veterinary drugs in food and environmental samples

10. Manual of Standard Operating Procedures for Veterinary Drug Residue Analysis (Spanish Edition)

International Nuclear Information System (INIS)

2017-01-01

Laboratories are crucial to national veterinary drug residue monitoring programmes. However, one of the main challenges laboratories encounter is obtaining access to relevant methods of analysis. Thus, in addition to training, providing technical advice and transferring technology, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has resolved to develop clear and practical manuals to support Member State laboratories. The Coordinated Research Project (CRP) on Development of Radiometric and Allied Analytical Methods to Strengthen Residue Control Programs for Antibiotic and Anthelmintic Veterinary Drug Residues has developed a number of analytical methods as standard operating procedures (SOPs), which are now compiled here. This publication contains SOPs on chromatographic and spectrometric techniques, as well as radioimmunoassay and associated screening techniques, for various anthelmintic and antimicrobial veterinary drug residue analysis. Some analytical method validation protocols are also included. The publication is primarily aimed at food and environmental safety laboratories involved in testing veterinary drug residues, including under organized national residue monitoring programmes. It is expected to enhance laboratory capacity building and competence through the use of radiometric and complementary tools and techniques. The publication is also relevant for applied research on residues of veterinary drugs in food and environmental samples

11. Validated high-performance thin-layer chromatographic (HPTLC method for simultaneous determination of nadifloxacin, mometasone furoate, and miconazole nitrate cream using fractional factorial design

Directory of Open Access Journals (Sweden)

Kalpana G. Patel

2016-07-01

Full Text Available A high-performance thin-layer chromatographic method for simultaneous determination of nadifloxacin, mometasone furoate, and miconazole nitrate was developed and validated as per International Conference on Harmonization guidelines. High-performance thin-layer chromatographic separation was performed on aluminum plates precoated with silica gel 60F254 and methanol:ethyl acetate:toluene: acetonitrile:3M ammonium formate in water (1:2.5:6.0:0.3:0.2, % v/v as optimized mobile phase at detection wavelength of 224 nm. The retardation factor (Rf values for nadifloxacin, mometasone furoate, and miconazole nitrate were 0.23, 0.70, and 0.59, respectively. Percent recoveries in terms of accuracy for the marketed formulation were found to be 98.35–99.76%, 99.36–99.65%, and 99.16–100.25% for nadifloxacin, mometasone furoate, and miconazole nitrate, respectively. The pooled percent relative standard deviation for repeatability and intermediate precision studies was found to be < 2% for three target analytes. The effect of four independent variables, methanol content in total mobile phase, wavelength, chamber saturation time, and solvent front, was evaluated by fractional factorial design for robustness testing. Amongst all four factors, volume of methanol in mobile phase appeared to have a possibly significant effect on retention factor of miconazole nitrate compared with the other two drugs nadifloxacin and mometasone furoate, and therefore it was important to be carefully controlled. In summary, a novel, simple, accurate, reproducible, and robust high-performance thin-layer chromatographic method was developed, which would be of use in quality control of these cream formulations.

12. Presentation Technique

International Nuclear Information System (INIS)

Froejmark, M.

1992-10-01

The report presents a wide, easily understandable description of presentation technique and man-machine communication. General fundamentals for the man-machine interface are illustrated, and the factors that affect the interface are described. A model is presented for describing the operators work situation, based on three different levels in the operators behaviour. The operator reacts routinely in the face of simple, known problems, and reacts in accordance with predetermined plans in the face of more complex, recognizable problems. Deep fundamental knowledge is necessary for truly complex questions. Today's technical status and future development have been studied. In the future, the operator interface will be based on standard software. Functions such as zooming, integration of video pictures, and sound reproduction will become common. Video walls may be expected to come into use in situations in which several persons simultaneously need access to the same information. A summary of the fundamental rules for the design of good picture ergonomics and design requirements for control rooms are included in the report. In conclusion, the report describes a presentation technique within the Distribution Automation and Demand Side Management area and analyses the know-how requirements within Vattenfall. If different systems are integrated, such as geographical information systems and operation monitoring systems, strict demands are made on the expertise of the users for achieving a user-friendly technique which is matched to the needs of the human being. (3 figs.)

13. Quantitative thin-layer chromatographic method of analysis of azithromycin in pure and capsule forms.

Science.gov (United States)

Khedr, Alaa; Sheha, Mahmoud

2003-01-01

A validated stability-indicating thin-layer chromatographic (TLC) method of the analysis of azithromycin (AZT) in bulk and capsule forms is developed. Both AZT potential impurity and degradation products can be selectively and accurately estimated in both raw material and product onto one precoated silica-gel TLC plate 60F254. The development system used is n-hexane-ethyl acetate-diethylamine (75:25:10, v/v/v). The separated bands are detected as brown to brownish red spots after spraying with modified Dragendorff's solution. The Rf values of AZT, azaerythromycin A, and the three degradation products are 0.54, 0.35, 0.40, 0.20, and 0.12, respectively. The optical densities of the separated spots are found to be linear in proportion to the amount used. The stress testing of AZT shows that azaerythromycin A is the major impurity and degradation product, accompanied by three other unknown degradation products. The stability of AZT is studied under accelerated conditions in order to provide a rapid indication of differences that might result from a change in the manufacturing process or source of the sample. The forced degradation conditions include the effect of heat, moisture, light, acid-base hydrolysis, sonication, and oxidation. The compatibility of AZT with the excipients used is also studied in the presence and absence of moisture. The amounts of AZT and azaerythromycin A are calculated from the corresponding linear calibration curve; however, the amounts of any other generated or detected unknown impurities are calculated as if it were AZT. This method shows enough selectivity, sensitivity, accuracy, precision, linearity-range, and robustness to satisfy Federal Drug Administration/International Conference of Harmonization regulatory requirements. The method developed can also be used for the purity testing of AZT raw material and capsules, content uniformity testing, dissolution testing, and stability testing of AZT capsules. The potential impurity profiles of

14. A unified ion chromatographic system for the determination of acidity and alkalinity.

Science.gov (United States)

Hu, W; Hasebe, K; Iles, A; Tanaka, K

2001-12-01

A unified ion chromatographic (IC) system was developed for the determination of acidity or alkalinity. Separation column used was a reversed-phase ODS packed column, which had been modified by saturating it with lithium dodecylsulfate. A slightly acidified LiCl (50 mM LiCl and 0.05 mM H2SO4) aqueous solution was used as the eluent. By conditioning the separation column in this way, both H+ and Li+ ions became bound to the stationary phase. Dodecylsulfate groups with Li+ counterions acted as cation-exchange sites for the separation of hydrogen ions (free acidity determination). The remaining dodecylsulfate groups, with H+ counterions acted as a titrant, which reacted with basic species (total alkalinity determination). The acidity or alkalinity of each sample was measured according to the change in conductance from the eluent baseline level. A positive peak was observed from those samples with a free acidity greater than their total alkalinity, due to the separation/elution of free H+ ions. A negative peak was observed from those samples with a free acidity less than their total alkalinity. This was due to an equivalent amount of eluent H+ ions being re-supplied to the stationary phase while the "solid titrant" consumed by the acid-base reaction was regenerated. The retention time for the peak corresponding to the acidity or alkalinity was governed by the retention time for H+ ions in this IC system. Samples with a free acidity greater than 2.25 microM (tested by determination of H+ ions in pure water in equilibrium with atmospheric CO2) could be analyzed by this method. A very similar detection level was obtained for alkalinity (tested by analyzing standard aqueous NaHCO3 solutions). Aqueous solutions of some strong-acid/strong-base inorganic salts were found to be slightly alkaline. This was measured as a percentage, relative to an NaHCO3 solution at the same concentration. Solutions of NaClO4, Na2SO4, NaI, NaNO3, and NaCl, gave comparative alkalinity values of 8

15. Estimating the sensitivity and specificity of Kato-Katz stool examination technique for detection of hookworms, Ascaris lumbricoides and Trichuris trichiura infections in humans in the absence of a 'gold standard'.

Science.gov (United States)

Tarafder, M R; Carabin, H; Joseph, L; Balolong, E; Olveda, R; McGarvey, S T

2010-03-15

The accuracy of the Kato-Katz technique in identifying individuals with soil-transmitted helminth (STH) infections is limited by day-to-day variation in helminth egg excretion, confusion with other parasites and the laboratory technicians' experience. We aimed to estimate the sensitivity and specificity of the Kato-Katz technique to detect infection with Ascaris lumbricoides, hookworm and Trichuris trichiura using a Bayesian approach in the absence of a 'gold standard'. Data were obtained from a longitudinal study conducted between January 2004 and December 2005 in Samar Province, the Philippines. Each participant provided between one and three stool samples over consecutive days. Stool samples were examined using the Kato-Katz technique and reported as positive or negative for STHs. In the presence of measurement error, the true status of each individual is considered as latent data. Using a Bayesian method, we calculated marginal posterior densities of sensitivity and specificity parameters from the product of the likelihood function of observed and latent data. A uniform prior distribution was used (beta distribution: alpha=1, beta=1). A total of 5624 individuals provided at least one stool sample. One, two and three stool samples were provided by 1582, 1893 and 2149 individuals, respectively. All STHs showed variation in test results from day to day. Sensitivity estimates of the Kato-Katz technique for one stool sample were 96.9% (95% Bayesian Credible Interval [BCI]: 96.1%, 97.6%), 65.2% (60.0%, 69.8%) and 91.4% (90.5%, 92.3%), for A. lumbricoides, hookworm and T. trichiura, respectively. Specificity estimates for one stool sample were 96.1% (95.5%, 96.7%), 93.8% (92.4%, 95.4%) and 94.4% (93.2%, 95.5%), for A. lumbricoides, hookworm and T. trichiura, respectively. Our results show that the Kato-Katz technique can perform with reasonable accuracy with one day's stool collection for A. lumbricoides and T. trichiura. Low sensitivity of the Kato-Katz for detection

16. A review on creatinine measurement techniques.

Science.gov (United States)

2012-08-15

This paper reviews the entire recent global tendency for creatinine measurement. Creatinine biosensors involve complex relationships between biology and micro-mechatronics to which the blood is subjected. Comparison between new and old methods shows that new techniques (e.g. Molecular Imprinted Polymers based algorithms) are better than old methods (e.g. Elisa) in terms of stability and linear range. All methods and their details for serum, plasma, urine and blood samples are surveyed. They are categorized into five main algorithms: optical, electrochemical, impedometrical, Ion Selective Field-Effect Transistor (ISFET) based technique and chromatography. Response time, detection limit, linear range and selectivity of reported sensors are discussed. Potentiometric measurement technique has the lowest response time of 4-10 s and the lowest detection limit of 0.28 nmol L(-1) belongs to chromatographic technique. Comparison between various techniques of measurements indicates that the best selectivity belongs to MIP based and chromatographic techniques. Copyright © 2012 Elsevier B.V. All rights reserved.

17. Steroid radioimmunoassay: contribution of standards to blank values, ch. 4

International Nuclear Information System (INIS)

Froelich, M.; Termorshuizen, W.; Kenter, E.; Molenaar, A.J.

1977-01-01

The sensitivity of the radioimmunoassay of steroids is considerably reduced by high blank values which may be derived in part from co-chromatographed standards. Blank levels approach the detection limit of the radioimmunoassay of aldosterone, testosterone and androstenedione when 10,000 dpm (30-35 pg) labelled steroids are used as reference standard. When 20 μg aldosterone, testosterone, or androstenedione is used as standard, blank levels of up to 12,800 pg were measured in the radioimmunoassay. Application of the standards on a separate strip does not improve the results. From the experiments it appeared that contamination took place by transport by the solvent

18. Comparative study for evaluating the cosmetic outcome of small-incision access retroperitoneoscopic technique (SMART) with standard retroperitoneoscopy using the Observer Scar Assessment Scale: are small incisions a big deal?

Science.gov (United States)

Al Nasser, Murad; Pini, Giovannalberto; Gözen, Ali Serdar; Elashry, Osama M; Akin, Yigit; Klein, Jan; Almouhissen, Turky; Rassweiler, Jens

2014-12-01

To compare the scars and cosmetic results of trocars of 3, 5, and 10 mm in cases by small-incision access retroperitoneoscopic technique pyeloplasty (SMARTp) and standard laparoscopy pyeloplasty (SLp). Between January 2012 and October 2013, 20 pyeloplasties were performed: 12 with SMARTp and 8 with SLp techniques. A 5-mm homemade balloon trocar was used to create the retroperitoneal space. In SMARTp, 3- and 5-mm trocars were used and in SLp, 5- and 10-mm trocars were used. All patients underwent a ureteral (Double-J) stent placement preoperatively. The study included a total of 72 trocar-site scars: 3 mm (24 scars), 5 mm (24 scars), and 10 mm (24 scars). Cosmetic outcome was assessed at the 3rd, 12th, and 24th month of surgeries by the Observer Scar Assessment Scale (OSAS). Mean age was 34.7±10.5 (19-52) years, and mean follow up was 18.7±9.2 months. Fifteen patients (75%) underwent Y-V plasty, and 5 (25%) underwent Anderson-Hynes pyeloplasty. Mean operative time was 125.4±28.7 minutes. There was only minimal blood loss, no need for conversion to standard laparoscopic or open pyeloplasty, no intraoperative complications, and only two postoperative complications were recorded: retroperitoneal hemorrhage and wound infection and both were treated conservatively. There were significant differences between objective questions of "vascularization" in a 3-mm trocar and "thickness" in a 10-mm trocar. Twenty-four months after surgery, the cosmetic data assessed by OSAS showed statistically significant differenecs in favor of the 3-mm trocar sites versus the 10-mm trocar sites (OSAS: 13.8±3.9 vs 24.6±1.7; p=0.006) with no statistically significant difference between 3- and 5-mm port sites. The SMARTp is proved to be an efficacious and tolerable procedure with better cosmetic results and can be used for the treatment of ureteropelvic junction obstruction (UPJO) in suitable patients. We believe that this technique is likely to become an established procedure.

19. Chromatographic and spectroscopic analysis of heavy crude oil mixtures with emphasis in nuclear magnetic resonance spectroscopy: A review

International Nuclear Information System (INIS)

Silva, Sandra L.; Silva, Artur M.S.; Ribeiro, Jorge C.; Martins, Fernando G.; Da Silva, Francisco A.; Silva, Carlos M.

2011-01-01

Graphical abstract: The chromatographic and spectroscopic techniques used to characterize heavy crude oils, although more focused in the nuclear magnetic resonance spectroscopy as the technique of choice, due to its capability to provide great information on the chemical nature of individual types of proton and carbon atoms in different and complex mixtures of crude oils are described. This review is based on 65 references and describes in a critical and interpretative ways the advantages of the NMR spectroscopy as a main technique to be used in crude oil refining industries that want to characterize crude oil fractions and the obtained refined products. Highlights: ► Chromatogrfaphic and spectroscopic techniques used to characterize heavy crude oils have been reviewed. ► This review describes in a critical and interpretative ways the advantages of the NMR spectroscopy as a main technique to be used in crude oil refining industries. ► The progress in the interpretation of the NMR spectra and of different multivariate data analyses and their potential in the identification and characterization of hydrocarbons and their physical and chemical properties have also been reviewed. - Abstract: The state of the art in the characterization of heavy crude oil mixtures is presented. This characterization can be done by different techniques, such as gas chromatography (GC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC), infrared spectroscopy (IR), Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Nuclear magnetic resonance spectroscopy is the technique of choice due to its capability to provide information on the chemical nature of individual types of hydrogen and carbon atoms in different and complex mixtures of crude oils. The progress made in the interpretation of the NMR spectra with the development of new NMR techniques and different multivariate data analyses could give relevant

20. High-performance liquid chromatographic radioenzymatic assay for plasma catecyholamines

International Nuclear Information System (INIS)

Klaniecki, T.S.; Corder, C.N.; McDonald, R.H. Jr.; Feldman, J.A.

1977-01-01

A new assay method for plasma catecholamimes (CA) requiring only 50 μl has been developed, which uses high performance liquid chromatography (HPLC). The norepinephrine (NE), dopamine (D), and epinephrine (E) compounds found in plasma are radioactively o-methylated with S-[methyl- 3 H]-adenosyl-L-methionine ( 3 H-SAM) 3 H-SAM by the reaction of catechol-o-methyl transferase (COMT). The reaction is terminated and a standard mixture of nonradioactive o-methylated analogues of NE, D, and E is added to act as a carrier. Following separation by HPLC, the D,L-normetanephrine (NMN), 3-methoxy-4-hydroxyphenylethyl-amine or 3-methoxytyramine (3-MOT), and metanephrine (MN) radioactive peaks are collected which represent NE, D, and E, respectively. Then MNM and MN are oxidized to vanillin, and 3-MOT is acetylated. The products are subsequently separated by solvent extraction. This is necessary in order to avoid high radioactive blanks and to allow quantitation of the radioactivity by liquid scintillation spectrometry. The mean supine levels of NE, D, and E in normal subjects were respectively 182, 33, and 87 pg/ml of plasma. Similar assays on patients with pheochromocytoma revealed 797, 80, and 470 pg/ml
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