#### Sample records for retinacular release rates

1. Lateral patellar retinacular release: changes over the last ten years.

Fonseca, Leonardo Pini Rosalem Marciano da; Kawatake, Ednei Haruo; Pochini, Alberto de Castro

2017-01-01

Lateral retinacular release is a useful resource in knee surgery that can be used for disorders of the extensor mechanism. For many years, it was indiscriminately used in the treatment of the various patellofemoral joint alterations, with conflicting functional results. This study aimed to analyze the changes that have occurred in the indications and clinical effectiveness of lateral retinacular release by reviewing the relevant literature of the past ten years, comparing it to the classic literature on the subject. It was found that less extensive releases decompress the lateral patellar facet, helping with pain control, while decreasing the risks of medial subluxation. Nowadays, there is clear evidence for its indication in the lateral patellar hypercompression syndrome associated with anterior knee pain, as long as there is no related instability; furthermore, it will normally play an adjuvant role in extensor mechanism alignment surgeries for cases of recurrent patellar instability. The initial results for symptomatic patellofemoral osteoarthritis are promising when lateral release is combined with cartilage debridement; in total knee replacement, it is more commonly used for the correction of valgus deformity in order to improve the components' congruency. Finally, distinguishing the different patellofemoral joint pathologies is seen as crucial in order to indicate this procedure. Further randomized control trials that compare surgical techniques with long-term results are still needed.

2. The effect of cold therapy on morbidity subsequent to arthroscopic lateral retinacular release.

Bert, J M; Stark, J G; Maschka, K; Chock, C

1991-09-01

Of all arthroscopic procedures, lateral retinacular release carries the greatest potential for morbidity. Complication rates of up to 7.2% have been reported, secondary to intraoperative and postoperative hematoma formation. A prospective double-blind study was conducted in which patients were randomly assigned to one of two groups treated with or without cold therapy for 24 hours postoperatively, subsequent to arthroscopic lateral retinacular release utilizing electrosurgery. Seventy-four percent of the patients treated with cold therapy had good to excellent results postoperatively, and none had significant complications. Thirty-two percent of the patients treated without cold therapy had good to excellent results postoperatively, and two patients experienced significant complications in this group.

3. Lateral retinacular release and patella ligament reconstruction under arthroscopy for recurrent patellar dislocations%外侧支持带松解联合髌骨韧带重建修复复发性髌骨脱位

陈辉; 王群; 燕双喜; 董天云; 邹海兵

2015-01-01

背景：关节镜检查能够直接动态观察髌股关节的对合关系，准确了解髌股关节异常是否可以完全纠正。目的：分析关节镜下外侧支持带松解联合髌骨韧带重建对复发性髌骨脱位的临床疗效。方法：复发性髌骨脱位患者共58例，随机将其分为对照组和观察组各29例，对照组患者给予常规手术行外侧支持带松解联合髌骨韧带重建，观察组患者给予关节镜下外侧支持带松解联合髌骨韧带重建。结果与结论：治疗前两组患者的Lysholm评分和Kujala评分的比较，差异均无显著性意义(P >0.05)；治疗12个月后两组患者的Lysholm评分和Kujala评分均升高，且观察组升高的更明显(P 0.05)；治疗12个月后两组患者的适合角和外侧髌股角CT测量值均降低，且观察组降低的更明显(P 0.05), but at 12 months after treatment, the Lysholm and Kujala scores were both increased in the two groups, especialy in the treatment group (P 0.05), and CT measurement values of the congruence angle and lateral patelofemoral angle were both decreased in the two groups, especialy in the experimental group, at 12 months after treatment. In addition, the operation time, healing time, and total effective rate were better in the experimental group than the control group (P < 0.05). These results indicate that the lateral retinacular release and ligament reconstruction under arthroscopy has a better effect on recurrent patelar dislocation.

4. Lateral retinacular release：changes in knee joint parameters%髌骨外侧支持带松解修复前后：膝关节参数变化的意义

隋金颇; 葛帮荣; 谢士成; 段国庆; 张元民; 赵晓伟

2015-01-01

背景：髌骨外侧支持带松解对于膝前痛在临床实践中是有意义的，但没有在膝关节参数测量下证实。目的：通过分析髌骨外侧支持带松解前后患者髌骨轴位X射线片上的相关参数，得出髌骨轴位片上对髌股关节紊乱最具临床意义的有效参数。方法：随机选取2009年2月至2013年12月济宁医学院附属医院关节科收治的50例膝前痛患者， OuterbridgeⅠ-Ⅲ级患者45例在关节镜下松解外侧支持带、修整关节软骨，另5例软骨损伤OuterbridgeⅣ级患者行外侧支持带松解的膝关节表面置换。结果与结论：与治疗前相比，外侧支持带松解后患者髌股指数、倾斜角及合适角均明显缩小(P 0.05)，且髌骨运动轨迹恢复到原来相对应的股骨髁中央位置，同时未观察到关节血肿、深静脉血栓形成及髌骨半脱位等并发症。说明外侧支持带松解对于治疗髌股外侧高压引起的膝前痛是有意义的。%BACKGROUND:Lateral retinacular release is effective to treat anterior knee pain, but it has not been confirmed through the parameters of the knee joint. OBJECTIVE: To analyze the relevant parameters on the axial X-ray films of the patela before and after lateral retinacular release and then to find out the efficient parameters for patelofemoral joint disorders on the axial X-ray film of the patela, which are of most clinical significance. METHODS: Fifty patients with anterior knee pain were included randomly who admitted at the Department of Joint Surgery, Affiliated Hospital of Jining Medical University from February 2009 to December 2013, including 45 cases of Outerbridge I-III undergoing arthroscopic lateral retinacular release+articular cartilage repair and 5 cases of Outerbridge IV undergoing lateral retinacular release+knee joint surface replacement. RESULTS AND CONCLUSION:After lateral retinacular release, the congruence angle, patelofemoral index and tilt angle were al

5. Coronal patellar osteotomy of the external facet combined with the release of the lateral retinaculum improves the clinical outcomes of isolated lateral release in lateral knee compartment syndrome.

Rosales-Varo, A P; Roda-Murillo, O; Prados-Olleta, N; García-Espona, M A

2016-01-01

To describe a novel coronal osteotomy of the external facet of the patella, and to evaluate if the outcomes of the treatment of lateral knee compartment syndrome (LKCS) with this osteotomy, combined with the release of the external lateral retinaculum, are better than the isolated lateral retinacular release. A prospective study with a 2 year follow up that included 70 patients diagnosed with LKCS, distributed into 2 groups. The first group included 50 patients on whom the lateral retinacular release combined with osteotomy was performed, and a second group on whom an isolated retinacular release was performed. Measurements were made using the Werner functional scale before the surgery and at 3, 12, and 24 months follow-up. There were significant differences in the overall functional state between the two groups after the surgery (better in the osteotomy group at all the intervals, Posteotomy technique, combined with lateral retinacular release, significantly improves the pain and the functional scale score of patients with LKCS after 2 years of follow-up, to a greater extent than isolated lateral retinacular release, including those in which there was evidence of degenerative signs. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

6. Clinical observation of arthroscopic lateral retinacular release in the treatment of patella lateral pressure syndrome%关节镜下外侧支持带松解治疗髌骨外侧高压综合征临床疗效观察

廖军; 孟庆才

2014-01-01

目的：探讨关节镜下外侧支持带松解术治疗髌骨外侧高压综合征（EL PS ）的临床疗效。方法选择2009年6月-2013年8月新疆医科大学附属中医医院关节外科收治的100例髌骨外侧高压综合征患者，将其分为两组：关节镜下行外侧支持带松解术58例（ALRR组），保守治疗42例（对照组），参考Lysholm膝关节功能评分评价临床疗效。结果两组患者随访3～15个月，平均8．6个月，对照组和 ALRR组有效率分别为85．71％和982．8％；两组患者治疗后Lysholm评分均较治疗前提高，差异有统计学意义（P ＜00．5）；两组患者治疗后Lysholm评分差异有统计学意义（P ＜00．5），ALRR组高于对照组。结论关节镜下外侧支持带松解术可有效地减轻髌骨外侧高压导致的髌股关节疼痛，且具备术后康复快、并发症少、膝关节功能恢复好等优势，其远期疗效有待进一步观察。%Objective To discuss the effective and clinical value of arthroscopic lateral retinaculum release treatment in excessive lateral pressure syndrome .Methods From June 2009 to August 2013 ,110 patients with patellar lateral pressure syndrome were randomly divided into lateral retinaculum under arthroscopy release (ALRR) treatment group (58 cases ,conservative treatment group (42 cases ,two groups of pa-tients with preoperative general data no statistically significant difference (P >0 0.5) ,there was no statis-tically significant difference Lysholm score before treatment (P >0 0.5) .Results Two groups of patients were followed up for 3-15 months ,an average of 8 6. months ,conservative treatment group and ALRR group effectiveness 85 7.1% ,98 2.8% respectively ;Lysholm score after treatment in both groups was im-proved ,the difference was statistically significant (P < 0 .05);Lysholm score after treatment in both groups ,the difference was statistically significant (P <0 0.5);Conclusion The lateral retinaculum

7. Patient release criteria for low dose rate brachytherapy implants.

Boyce, Dale E; Sheetz, Michael A

2013-04-01

A lack of consensus regarding a model governing the release of patients following sealed source brachytherapy has led to a set of patient release policies that vary from institution to institution. The U.S. Nuclear Regulatory Commission has issued regulatory guidance on patient release in NUREG 1556, Volume 9, Rev. 2, Appendix U, which allows calculation of release limits following implant brachytherapy. While the formalism presented in NUREG is meaningful for the calculation of release limits in the context of relatively high energy gamma emitters, it does not estimate accurately the effective dose equivalent for the common low dose rate brachytherapy sources Cs, I, and Pd. NUREG 1556 states that patient release may be based on patient-specific calculations as long as the calculation is documented. This work is intended to provide a format for patient-specific calculations to be used for the consideration of patients' release following the implantation of certain low dose rate brachytherapy isotopes.

8. Determining drug release rates of hydrophobic compounds from nanocarriers.

D'Addio, Suzanne M; Bukari, Abdallah A; Dawoud, Mohammed; Bunjes, Heike; Rinaldi, Carlos; Prud'homme, Robert K

2016-07-28

Obtaining meaningful drug release profiles for drug formulations is essential prior to in vivo testing and for ensuring consistent quality. The release kinetics of hydrophobic drugs from nanocarriers (NCs) are not well understood because the standard protocols for maintaining sink conditions and sampling are not valid owing to mass transfer and solubility limitations. In this work, a new in vitroassay protocol based on 'lipid sinks' and magnetic separation produces release conditions that mimic the concentrations of lipid membranes and lipoproteins in vivo, facilitates separation, and thus allows determination of intrinsic release rates of drugs from NCs. The assay protocol is validated by (i) determining the magnetic separation efficiency, (ii) demonstrating that sink condition requirements are met, and (iii) accounting for drug by completing a mass balance. NCs of itraconazole and cyclosporine A (CsA) were prepared and the drug release profiles were determined. This release protocol has been used to compare the drug release from a polymer stabilized NC of CsA to a solid drug NP of CsA alone. These data have led to the finding that stabilizing block copolymer layers have a retarding effect on drug release from NCs, reducing the rate of CsA release fourfold compared with the nanoparticle without a polymer coating.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

9. Release-rate calorimetry of multilayered materials for aircraft seats

Fewell, L. L.; Parker, J. A.; Duskin, F.; Speith, H.; Trabold, E.

1980-01-01

Multilayered samples of contemporary and improved fire-resistant aircraft seat materials were evaluated for their rates of heat release and smoke generation. Top layers with glass-fiber block cushion were evaluated to determine which materials, based on their minimum contributions to the total heat release of the multilayered assembly, may be added or deleted. The smoke and heat release rates of multilayered seat materials were then measured at heat fluxes of 1.5 and 3.5 W/cm2. Abrasion tests were conducted on the decorative fabric covering and slip sheet to ascertain service life and compatibility of layers

10. ISOPAR L RELEASE RATES FROM SALTSTONE USING SIMULATED SALT SOLUTIONS

Zamecnik, J; Michael Bronikowski, M; Alex Cozzi, A; Russell Eibling, R; Charles Nash, C

2008-07-31

The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Decontaminated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour, the Isopar{reg_sign} L in the vault headspace is well mixed, and each pour displaces an equivalent volume of headspace, the maximum concentration of Isopar{reg_sign} L in the DSS to assure 25% of the lower flammable limit is not exceeded has been determined to be about 4 ppm. The amount allowed would be higher if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the amount of Isopar{reg_sign} L released versus time can be treated as a percentage of initial amount present; there was no statistically significant dependence of the release rate on the initial concentration. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release rate is larger than at lower temperatures. Initial curing temperature was found to be very important as slight variations during the first few hours or days had a significant effect on the amount of Isopar{reg_sign} L released. Short scoping

11. 77 FR 47918 - Information Collection Activities (Released Rates)

2012-08-10

... Surface Transportation Board Information Collection Activities (Released Rates) AGENCY: Surface... notice of its intent to seek from the Office of Management and Budget (OMB) approval of the information... required movers to provide certain information concerning the two available cargo-liability options on...

12. Anthropogenic carbon release rate unprecedented during past 66 million years

Zeebe, R. E.; Ridgwell, A.; Zachos, J. C.

2015-12-01

Carbon release rates from anthropogenic sources have reached a record high of about 10 Pg C/y in 2013. However, due to uncertainties in the strength of climate system feedbacks, the full impact of the rapid carbon release on the Earth system is difficult to predict with confidence. Geologic analogues from past transient climate changes could provide invaluable constraints but only if the associated carbon release rates can be reliably reconstructed. We present a new technique - based on combined data-model analysis - to extract rates of change from the geological record, without the need for a stratigraphic age model. Given currently available records, we then show that the present anthropogenic carbon release rate is unprecedented during the Cenozoic (past 66 million years) by at least an order of magnitude. Our results have important implications for our ability to use past analogues to predict future changes, including constraints on climate sensitivity, ocean acidification, and impacts on marine and terrestrial ecosystems. For example, the fact that we have effectively entered an era of 'no analogue' state presents fundamental challenges to constraining forward modeling. Furthermore, future ecosystem disruptions will likely exceed the relatively limited extinctions observed during climate aberrations throughout the Cenozoic.

13. ISOPAR L Release Rates from Saltstone Using Simulated Salt Solutions

Bronikowski, M

2006-02-06

The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) and the Salt Waste Processing Facility (SWPF) will produce a Deactivated Salt Solution (DSS) that will go to the Saltstone Production Facility (SPF). Recent information indicates that solvent entrainment in the DSS is larger than expected. The main concern is with Isopar{reg_sign} L, the diluent in the solvent mixture, and its flammability in the saltstone vault. If it is assumed that all the Isopar{reg_sign} L is released instantaneously into the vault from the curing grout before each subsequent pour; the Isopar{reg_sign} L in the vault headspace is well mixed; and each pour displaces an equivalent volume of headspace, the allowable concentration of Isopar{reg_sign} L in the DSS sent to SPF has been calculated at approximately 4 ppm. The amount allowed would be higher, if the release from grout were significantly less. The Savannah River National Laboratory was tasked with determining the release of Isopar{reg_sign} L from saltstone prepared with a simulated DSS with Isopar{reg_sign} L concentrations ranging from 50 mg/L to 200 mg/L in the salt fraction and with test temperatures ranging from ambient to 95 C. The results from the curing of the saltstone showed that the Isopar{reg_sign} L release data can be treated as a percentage of initial concentration in the concentration range studied. The majority of the Isopar{reg_sign} L that was released over the test duration was released in the first few days. The release of Isopar{reg_sign} L begins immediately and the rate of release decreases over time. At higher temperatures the immediate release is larger than at lower temperatures. In one test at 95 C essentially all of the Isopar{reg_sign} L was released in three months. Initial curing temperature was found to be very important as slight variations during the first few days affected the final Isopar{reg_sign} L amount released. Short scoping tests at 95 C with solvent containing all components (Isopar

14. Simultaneous drug release at different rates from biodegradable polyurethane foams.

Sivak, Wesley N; Zhang, Jianying; Petoud, Stephané; Beckman, Eric J

2009-09-01

In this study, we present an approach for the simultaneous release of multiple drug compounds at different rates from single-phase polyurethane foams constructed from lysine diisocyanate (LDI) and glycerol. The anti-cancer compounds DB-67 and doxorubicin were covalently incorporated into polyurethane foams, whereby drug release can then occur in concert with material degradation. To begin, the reactions of DB-67 and doxorubicin with LDI in the presence of a tertiary amine catalyst were monitored with infrared spectroscopy; each compound formed urethane linkages with LDI. Fluorescent spectra of DB-67 and doxorubicin were then recorded in phosphate-buffered saline, pH 7.4 (PBS), to ensure that each anti-cancer compound could be quantitatively detected alone and in combination. Doxorubicin and DB-67 were then incorporated into a series of degradable LDI-glycerol polyurethane foams alone and in combination with one another. The sol content, average porosity and drug distribution throughout each foam sample was measured and found to be similar amongst all foam samples. The stability of DB-67 and doxorubicin's fluorescent signal was then assessed over a 2-week period at 70 degrees C. Release rates of the compounds from the foams were assessed over a 10-week period at 4, 22, 37 and 70 degrees C by way of fluorescence spectroscopy. Release was found to be temperature-dependent, with rates related to the chemical structure of the incorporated drug. This study demonstrates that differential release of covalently bound drugs is possible from simple single-phase, degradable polyurethane foams.

15. Comodulation masking release in bit-rate reduction systems

Vestergaard, Martin D.; Rasmussen, Karsten Bo; Poulsen, Torben

1999-01-01

It has been suggested that the level dependence of the upper masking slopebe utilised in perceptual models in bit-rate reduction systems. However,comodulation masking release (CMR) phenomena lead to a reduction of themasking effect when a masker and a probe signal are amplitude modulated withthe...... same frequency. In bit-rate reduction systems the masker would be theaudio signal and the probe signal would represent the quantization noise.Masking curves have been determined for sinusoids and 1-Bark-wide noisemaskers in order to investigate the risk of CMR, when quantizing depths arefixed...

16. Comodulation masking release in bit-rate reduction systems

Vestergaard, Martin David; Rasmussen, Karsten Bo; Poulsen, Torben

1999-01-01

It has been suggested that the level dependence of the upper masking slope be utilized in perceptual models in bit-rate reduction systems. However, comodulation masking release (CMR) phenomena lead to a reduction of the masking effect when a masker and a probe signal are amplitude modulated...... with the same frequency. In bit-rate reduction systems the masker would be the audio signal and the probe signal would represent the quantization noise. Masking curves have been determined for sinusoids and 1-Bark-wide noise maskers in order to investigate the risk of CMR, when quantizing depths are fixed.......75. A CMR of up to 10 dB was obtained at a distance of 6 Bark above the masker. The amount of CMR was found to depend on the presentation level of the masker; a higher masker level leads to a higher CMR effect. Hence, the risk of CMR affecting the subjective performance of bit-rate reduction systems cannot...

17. Inverse modelling of radionuclide release rates using gamma dose rate observations

Hamburger, Thomas; Evangeliou, Nikolaos; Stohl, Andreas; von Haustein, Christoph; Thummerer, Severin; Wallner, Christian

2015-04-01

Severe accidents in nuclear power plants such as the historical accident in Chernobyl 1986 or the more recent disaster in the Fukushima Dai-ichi nuclear power plant in 2011 have drastic impacts on the population and environment. Observations and dispersion modelling of the released radionuclides help to assess the regional impact of such nuclear accidents. Modelling the increase of regional radionuclide activity concentrations, which results from nuclear accidents, underlies a multiplicity of uncertainties. One of the most significant uncertainties is the estimation of the source term. That is, the time dependent quantification of the released spectrum of radionuclides during the course of the nuclear accident. The quantification of the source term may either remain uncertain (e.g. Chernobyl, Devell et al., 1995) or rely on estimates given by the operators of the nuclear power plant. Precise measurements are mostly missing due to practical limitations during the accident. The release rates of radionuclides at the accident site can be estimated using inverse modelling (Davoine and Bocquet, 2007). The accuracy of the method depends amongst others on the availability, reliability and the resolution in time and space of the used observations. Radionuclide activity concentrations are observed on a relatively sparse grid and the temporal resolution of available data may be low within the order of hours or a day. Gamma dose rates, on the other hand, are observed routinely on a much denser grid and higher temporal resolution and provide therefore a wider basis for inverse modelling (Saunier et al., 2013). We present a new inversion approach, which combines an atmospheric dispersion model and observations of radionuclide activity concentrations and gamma dose rates to obtain the source term of radionuclides. We use the Lagrangian particle dispersion model FLEXPART (Stohl et al., 1998; Stohl et al., 2005) to model the atmospheric transport of the released radionuclides. The

18. 75 FR 66057 - Waybill Data Released in Three-Benchmark Rail Rate Proceedings

2010-10-27

... Surface Transportation Board 49 CFR Part 1244 Waybill Data Released in Three-Benchmark Rail Rate... Board is republishing its April 2, 2010 proposal to amend its rules with respect to the Three-Benchmark... rationale and regulatory objectives. This proposal provides for release to the parties to a...

19. Effects of flow and water chemistry on lead release rates from pipe scales.

Xie, Yanjiao; Giammar, Daniel E

2011-12-01

Lead release from pipe scales was investigated under different water compositions, stagnation times, and flow regimes. Pipe scales containing PbO(2) and hydrocerussite (Pb(3)(OH)(2)(CO(3))(2)) were developed on lead pipes by conditioning the pipes with water containing free chlorine for eight months. Water chemistry and the composition of the pipe scales are two key factors affecting lead release from pipe scales. The water rarely reached equilibrium with pipe scales within one day, which makes solid-water contact time and corrosion product dissolution rates the controlling factors of lead concentrations for the conditions tested. Among five water compositions studied, a solution with orthophosphate had the lowest dissolved lead release rate and highest particulate lead release rate. Free chlorine also decreased the dissolved lead release rate at stagnant conditions. Water flow increased rates of release of both dissolved and particulate lead by accelerating the mass transfer of lead out of the porous pipe scales and by physically destabilizing pipe scales. Dissolved lead comprised the majority of the lead released at both stagnant and laminar flow conditions. Copyright Â© 2011 Elsevier Ltd. All rights reserved.

20. Experimental study on new monitoring method of radon release rate from uranium tailings

Fu Jin; HanYaozHao; He Wen Xing; Zhang Biao

2002-01-01

Two new monitoring methods of radon release rate from uranium tailings are introduced. They are the active carbon absorption and gamma energy spectrum method. The instrument and sampler of active carbon absorption is presented with the manufacture, function, performance and calibration, the conditional test of the method and its measuring contrast to that of local static method. One-year continuous in-site monitoring of radon release rate of uranium tailings was done. The annual change regularity of radon release rate from uranium tailings was observed. The optimum season and condition of monitoring the annual average radon release rate are summarized. The parameter monitoring, calculating method and experimentation of gamma energy spectrum method is discussed

1. Effect of Starch Sources on the Release Rates of Herbicides Encapsulated

2006-01-01

The effects of starch sources on the behaviors of starch matrices and on the rates of herbicides released from the matrices were studied for slow release. The starches considered include native corn starch, wheat starch, potato starch and cassava starch. The matrices were prepared through encapsulating 2,4-dichlorophenoxyacetic or 2,4,5-trichlorophenoxyacetic acids as model herbicides with hot-gelatinized starch pastes. The encapsulation was evaluated in terms of herbicide content, swellability, encapsulation efficiency, and release rate. The results show that starch sources play an important role on the matrix behaviors and on release rates. The rate of 2,4-D released follows the order: wheat starch < potato starch < corn starch < cassava starch. And for the rate of 2,4,5-T, this order is nearly the same only with an exception that the late two kinds of starch are similar. It is also demonstrated that herbicides with different water solubility show different release rates, no matter what type of starch is used as the matrices.

2. Levonorgestrel release rates over 5 years with the Liletta® 52-mg intrauterine system.

Creinin, Mitchell D; Jansen, Rolf; Starr, Robert M; Gobburu, Joga; Gopalakrishnan, Mathangi; Olariu, Andrea

2016-10-01

To understand the potential duration of action for Liletta®, we conducted this study to estimate levonorgestrel (LNG) release rates over approximately 5½years of product use. Clinical sites in the U.S. Phase 3 study of Liletta collected the LNG intrauterine systems (IUSs) from women who discontinued the study. We randomly selected samples within 90-day intervals after discontinuation of IUS use through 900days (approximately 2.5years) and 180-day intervals for the remaining duration through 5.4years (1980days) to evaluate residual LNG content. We also performed an initial LNG content analysis using 10 randomly selected samples from a single lot. We calculated the average ex vivo release rate using the residual LNG content over the duration of the analysis. We analyzed 64 samples within 90-day intervals (range 6-10 samples per interval) through 900days and 36 samples within 180-day intervals (6 samples per interval) for the remaining duration. The initial content analysis averaged 52.0±1.8mg. We calculated an average initial release rate of 19.5mcg/day that decreased to 17.0, 14.8, 12.9, 11.3 and 9.8mcg/day after 1, 2, 3, 4 and 5years, respectively. The 5-year average release rate is 14.7mcg/day. The estimated initial LNG release rate and gradual decay of the estimated release rate are consistent with the target design and function of the product. The calculated LNG content and release rate curves support the continued evaluation of Liletta as a contraceptive for 5 or more years of use. Liletta LNG content and release rates are comparable to published data for another LNG 52-mg IUS. The release rate at 5years is more than double the published release rate at 3years with an LNG 13.5-mg IUS, suggesting continued efficacy of Liletta beyond 5years. Copyright © 2016 Elsevier Inc. All rights reserved.

3. Evaluation of rate of swelling and erosion of verapamil (VRP) sustained-release matrix tablets.

Khamanga, Sandile M; Walker, Roderick B

2006-01-01

Tablets manufactured in-house were compared to a marketed sustained-release product of verapamil to investigate the rate of hydration, erosion, and drug-release mechanism by measuring the wet and subsequent dry weights of the products. Swelling and erosion rates depended on the polymer and granulating fluid used, which ultimately pointed to their permeability characteristics. Erosion rate of the marketed product was highest, which suggests that the gel layer that formed around these tablets was weak as opposed to the robust and resistant layers of test products. Anomalous and near zero-order transport mechanisms were dominant in tests and commercial product, respectively.

4. 75 FR 16712 - Waybill Data Released in Three-Benchmark Rail Rate Proceedings

2010-04-02

... TRANSPORTATION Surface Transportation Board 49 CFR Part 1244 Waybill Data Released in Three-Benchmark Rail Rate... Board proposes to amend its rules with respect to the Three-Benchmark methodology used to adjudicate... simplified stand-alone cost approach for medium-size rail rate disputes and revising its...

5. Production and release rate of (37)Ar from the UT TRIGA Mark-II research reactor.

Johnson, Christine; Biegalski, Steven R; Artnak, Edward J; Moll, Ethan; Haas, Derek A; Lowrey, Justin D; Aalseth, Craig E; Seifert, Allen; Mace, Emily K; Woods, Vincent T; Humble, Paul

2017-02-01

Air samples were taken at various locations around The University of Texas at Austin's TRIGA Mark II research reactor and analyzed to determine the concentrations of (37)Ar, (41)Ar, and (133)Xe present. The measured ratio of (37)Ar/(41)Ar and historical records of (41)Ar releases were then utilized to estimate an annual average release rate of (37)Ar from the reactor facility. Using the calculated release rate, atmospheric transport modeling was performed in order to determine the potential impact of research reactor operations on nearby treaty verification activities. Results suggest that small research reactors (∼1 MWt) do not release (37)Ar in concentrations measurable by currently proposed OSI detection equipment.

6. Relationship between in vivo skin blanching and in vitro release rate for betamethasone valerate creams.

Shah, V P; Elkins, J; Skelly, J P

1992-01-01

Betamethasone valerate creams from two firms were evaluated using the skin blanching procedure. In both studies, the same cream formulation exhibited significantly higher blanching compared to the other product. An in vitro release rate was determined for these betamethasone valerate cream products using a diffusion cell system, with a cellulose acetate membrane and a 60% ethanol:water receptor medium. The release rate (flux) of betamethasone valerate was higher for the higher blanching formulation and was statistically different from the other product. The integrity of the cellulose acetate membrane in 60% ethanol:water mixture was ascertained using hydrocortisone cream product. The in vitro drug release method, using a diffusion cell system and a synthetic membrane, can serve as a good quality control test method for topical creams.

7. Calculating the rate of exothermic energy release for catalytic converter efficiency monitoring

Hepburn, J.S.; Meitzler, A.H. [Ford Motor Co., Dearborn, MI (United States)

1995-12-31

This paper reports on the development of a new methodology for OBD-II catalyst efficiency monitoring. Temperature measurements taken from the center of the catalyst substrate or near the exterior surface of the catalyst brick were used in conjunction with macroscopic energy balances to calculate the instantaneous rate of exothermic energy generation within the catalyst. The total calculated rate of exothermic energy release over the FTP test cycle was within 10% of the actual or theoretical value and provided a good indicator of catalyst light-off for a variety of aged catalytic converters. Normalization of the rate of exothermic energy release in the front section of the converter by the mass flow rate of air inducted through the engine was found to provide a simple yet practical means of monitoring the converter under both FTP and varying types of road driving.

8. Measurement of semiochemical release rates with a dedicated environmental control system

nsect semiochemical dispensers are commonly deployed under variable environmental conditions over a specified time frame; however, predictions of their longevity are hampered by a lack of methods to accurately monitor and predict how the primary variables affect the semiochemical release rate. Herei...

9. Release rates of Al from inorganic and organic compounds in a sandy podzol, during laboratory experiments

Salm, van der C.; Westerveld, J.W.; Verstraten, J.M.

2000-01-01

Research with respect to release rates of Al and Al concentrations in the soil solution has led to two contrasting hypotheses, stressing either the importance of kinetically constrained dissolution reactions or the role of complexation of Al to soil organic matter. The existence of two contrasting

10. Optimum timing for integrated pest management: modelling rates of pesticide application and natural enemy releases.

Tang, Sanyi; Tang, Guangyao; Cheke, Robert A

2010-05-21

Many factors including pest natural enemy ratios, starting densities, timings of natural enemy releases, dosages and timings of insecticide applications and instantaneous killing rates of pesticides on both pests and natural enemies can affect the success of IPM control programmes. To address how such factors influence successful pest control, hybrid impulsive pest-natural enemy models with different frequencies of pesticide sprays and natural enemy releases were proposed and analyzed. With releasing both more or less frequent than the sprays, a stability threshold condition for a pest eradication periodic solution is provided. Moreover, the effects of times of spraying pesticides (or releasing natural enemies) and control tactics on the threshold condition were investigated with regard to the extent of depression or resurgence resulting from pulses of pesticide applications. Multiple attractors from which the pest population oscillates with different amplitudes can coexist for a wide range of parameters and the switch-like transitions among these attractors showed that varying dosages and frequencies of insecticide applications and the numbers of natural enemies released are crucial. To see how the pesticide applications could be reduced, we developed a model involving periodic releases of natural enemies with chemical control applied only when the densities of the pest reached the given Economic Threshold. The results indicate that the pest outbreak period or frequency largely depends on the initial densities and the control tactics.

11. Effect of CaF2 content on rate of fluoride release from filled resins.

Anusavice, K J; Zhang, N-Z; Shen, C

2005-05-01

Information on the time-dependent release of fluoride from filled resins containing fluoride particles as a function of particle content and solution pH is limited. This study characterized the fluoride ion release from filled resins containing CaF2 particles as a function of filler content and pH. Urethane dimethacrylate and triethylene glycol dimethacrylate resins were used to make filled-resin disks containing 9.09, 23.08, or 33.33 mass% CaF2 filler. Fluoride ion release for the 9.09 mass% concentration was independent of pH. Increasing the filler content from 9.09 to 33.33 mass% increased the fluoride release rate in pH 4.0 buffer solution, because of greater surface degradation. Fluoride ion release from disks stored in pH 6.0 buffer solutions occurred mainly by diffusion from disk surfaces, while fluoride release from disks in pH 4.0 buffers was controlled by diffusion from disk surfaces and degeneration of the resin matrix, which exposed more CaF2 particle surface area.

12. Study on encapsulation of chlorine dioxide in gelatin microsphere for reducing release rate.

Ci, Ying; Wang, Lin; Guo, Yanchuan; Sun, Ruixue; Wang, Xijie; Li, Jinyou

2015-01-01

This study aims to explore the effects of encapsulation of chlorine dioxide in a hydrophilic biodegradable polymer gelatin to reduce its release rate. An emulsification-coacervation method was adopted. The characterizations of chlorine dioxide-gelatin microspheres were described. Using UV-vis spectrophotometer the λmax of chlorine dioxide was observed at 358 nm. The particle size and distribution of chlorine oxide-gelatin microspheres was measured by a dynamic light scattering (DLS) method, the diameter was (1400~1900) nm. The entrapment of chlorine dioxide-gelatin microspheres was confirmed by IR. The surface morphology, size, and shape of chlorine dioxide-gelatin microspheres were analyzed using Scanning electron microscope (SEM). It showed that the encapsulated microspheres size was around 2000 nm with uniform distribution. The percentage entrapment of chlorine dioxide in the encapsulated samples was about 80~85%. A slow release study of chlorine dioxide from the encapsulated biopolymer (gelatin) in air was also carried out, which showed continuous release up to ten days. It can be concluded that it is possible to make a slow release formulation of ClO2 by entrapped in a hydrophilic biodegradable polymer gelatin. ClO2-gelatin microspheres can stable release low concentration ClO2 gas over an extended period.

13. Impaired sarcoplasmic reticulum Ca(2+) release rate after fatiguing stimulation in rat skeletal muscle

2000-01-01

to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which......The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate...... during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P

14. Variation of strain energy release rate with plate thickness. [fracture mode transition

Sih, G. C.; Hartranft, R. J.

1973-01-01

An analytical model of a through-thickness crack in a statically stretched plate is presented in which the crack front stress state is permitted to vary in the direction of the plate thickness. The amplitude or intensity of this stress field can be made nearly constant over a major portion of the interior crack front which is in a state of plane strain. The average amount of work available for extending a small segment of the crack across the thickness is associated with an energy release rate quantity in a manner similar to the two-dimensional Griffith crack model. The theoretically calculated energy release rate is shown to increase with increasing plate thickness, indicating that available work for crack extension is higher in a thicker plate.

15. Diurnal fluctuations in root oxygen release rate and dissolved oxygen budget in wetland mesocosm

Dong, C.; Zhu, W; Zhao, Y. Q.; Gao, M

2011-01-01

To assess the role of plants for oxygen offering in constructed wetlands, this study experimentally evaluated the amount of root oxygen release rate using mass balance method. The mass balance calculation is based on the following components: respiratory oxygen consumption of the roots; oxygen required for degradation of the organic matters; oxygen required for nitrification; and the amount of dissolved oxygen in the influent, effluent and substrate water. Experimental results have demonstrat...

16. Study on encapsulation of chlorine dioxide in gelatin microsphere for reducing release rate

Ci, Ying; Wang,Lin; Guo, YanChuan; Sun, Ruixue; Wang, Xijie; Li, Jinyou

2015-01-01

Objective: This study aims to explore the effects of encapsulation of chlorine dioxide in a hydrophilic biodegradable polymer gelatin to reduce its release rate. Methods: An emulsification-coacervation method was adopted. The characterizations of chlorine dioxide-gelatin microspheres were described. Using UV-vis spectrophotometer the λmax of chlorine dioxide was observed at 358 nm. The particle size and distribution of chlorine oxide-gelatin microspheres was measured by a dynamic light scatte...

17. A methodology to study cyclic debond growth at constant mode-mixity and energy release rate

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

2010-01-01

It is well known that face/core debond crack propagation is governed by the critical energy release rate (fracture toughness) and mode-mixity at the crack tip. Thus, the current study focuses on the developing of a methodology to perform fatigue crack growth experiments of debonded sandwich...... and better control of loading conditions at the crack tip will be the most relevant outcomes of using the proposed fatigue test method....

18. Modulation of Tenoxicam release from hydrophilic matrix: modulator membrane versus rate-controlling membrane.

El-Nabarawi, Mohamed Ahmed

2005-09-01

This paper describes the preparation of two layered device comprising of tenoxicam containing layer and a drug free membrane layer based on Geomatrix Technology. Our device based on bilaminated films which produced by a casting/solvent evaporation technique. The drug-hydroxypropyl methylcellulose (HPMC) layer was covered by drug free membrane layer composed of a mixture of different ratios of HPMC and ethyl cellulose (EC). The prepared devices were evaluated for thickness, weight, drug content uniformity, water absorption capacity and in-vitro drug release. The films were also evaluated for appearance, smoothness and transparency. The influence of drug free membrane layer composition and thickness on the drug release pattern was studied on 12 devices (D1 to D12). The results indicate that, the release of drug from HPMC matrixes without the drug free membrane layer was fast and follows diffusion controlled mechanism. The release of drug from the devices D1, D4, D9 and D12 follow the same mechanism, while the release of drug from other devices become linear with time (zero order) and extended for long time especially when thickness and the ratio of EC was increased in the drug free membrane layer. From this study it is concluded that, changing the geometry of drug layer by addition of drug free membrane layer and changing its composition and thickness plays an important role in determining whether the drug free membrane layer is rate-controlling or modulator membrane. Hence it can facilitate the development of different pharmaceutical products with different release pattern.

19. The Effects of Different Amounts of Controlled Release Fertilizer on the Root Growth and the Filling Rate in Winter Wheat

Meng Li; Jingtian Yang; Liyuan Yan; Yan Shi

2014-01-01

In order to increase the fertilizer use efficiency and yield in winter wheat, the effects of controlled release fertilizer on the root growth and the filling rate in winter wheat by applying different amounts of controlled release fertilizer had been studied in open field. The results indicated that conventional complex fertilizer and controlled release fertilizer could cause corresponding changes of the wheat root activity, dry root weight, root-shoot ratio and filling rate, but the fertiliz...

20. The Effects of Different Amounts of Controlled Release Fertilizer on the Root Growth and the Filling Rate in Winter Wheat

Meng Li; Jingtian Yang; Liyuan Yan; Yan Shi

2014-01-01

In order to increase the fertilizer use efficiency and yield in winter wheat, the effects of controlled release fertilizer on the root growth and the filling rate in winter wheat by applying different amounts of controlled release fertilizer had been studied in open field. The results indicated that conventional complex fertilizer and controlled release fertilizer could cause corresponding changes of the wheat root activity, dry root weight, root-shoot ratio and filling rate, but the fertiliz...

1. Study on release rate of latent heat in Czochralski silicon growth

REN Bingyan; YANG Jiankun; LI Yanlin; LIU Xiaoping; WANG Minhua

2006-01-01

The pulling rate in czochralski silicon (CZSi) growth is important for reducing the cost of solar cell.In this paper, double-heater, heat shield and composite argon duct system were introduced in the Ф450 mm hot zone of a Czochralski furnace.The pulling rate under different thermal system was recorded in experiments.Argon flow and temperature fields were simulated by finite element method(FEM).Experimental results and numerical simulation indicate that double-heater and composite argon duct system can enhance obviously the release rate of latent heat.In Φ 200 mm Czochralski silicon (CZSi) growth, average pulling rate can increase from 0.6 mm·min-1 in the conventional hot zone to 0.8 mm·min-1 in the modified hot zone.

2. Studies on the codling moth (Lepidoptera: Tortricidae) response to different codlemone release rates.

Vacas, S; Miñarro, M; Bosch, M D; Primo, J; Navarro-Llopis, V

2013-12-01

The response of the codling moth (Cydia pomonella L. (Lepidoptera: Tortricidae)) to different emission values of its main pheromone component, 8E,10E-dodecadien-1-ol (codlemone), was investigated in three field trials conducted in plots without mating disruption treatments. Moth catches obtained in traps baited with pheromone dispensers were correlated with the corresponding codlemone release rates by multiple regression analysis. In a preliminary trial conducted in Lleida (NE Spain), a decreasing trend of captures was observed based on increasing pheromone levels. After this, the pheromone release profiles of the pheromone dispensers were studied, in parallel with the field trials, by residual codlemone extraction and gas chromatography quantification. In the trials carried out in Asturias (NW Spain), a correlation between trap catches and emission levels (within the range from 11 to 1,078 μg/d) was found and fitted a logarithmic model. Captures followed a decreasing linear trend in the range of emission rates from 11 to 134 μg/d. Given that release values comprised between 11 and 67 μg/d did not lead to significantly different catches in traps, this emission range could be considered to develop effective formulations for attraction purposes when mating disruption is not acting in the environment.

3. WATER HYACINTH: A POSSIBLE ALTERNATIVE RATE RETARDING NATURAL POLYMER USED IN SUSTAINED RELEASE TABLET DESIGN

Sabera eKhatun

2014-06-01

Full Text Available In recent years natural polymers have been widely used, because of their effectiveness and availability over synthetic polymers. In this present investigation matrix tablets of Metformin hydrochloride were formulated using Water hyacinth powder and its rate retardant activity was studied. Tablets were prepared using wet granulation method with 8% starch as granulating agent and 5%, 10%, 15%, 20%, 25% and 30% of Water hyacinth powder to the drug. In preformulation study, angle of repose, Carr’s Index and Hausner ratio were calculated. Fourier Transform Infrared Spectroscopy (FTIR, Differential Scanning Calorimetry (DSC and Scanning Electron Microscopy (SEM studies were performed and no interactions were found between drug and excipients. Weight variation, friability, hardness, thickness, diameter, and in vitro release study were performed with the prepared matrix tablets. Dissolution studies were conducted using USP type II apparatus at a speed of 100 rpm at 37oC ± 0.5 temperature, for 8 hours. All the formulations comply with both BP and USP requirements, but among all the formulations F-1 (5% of Water hyacinth was the best fitted formula. The drug release patterns were explained in different kinetic models such as Zero order, First order, Higuchi, Hixson Crowell and Korsmeyer-Peppas equations. The current investigation implies that Water hyacinth has the potential to be used as a rate-retarding agent in sustained release drug formulations.

4. LEAK: A source term generator for evaluating release rates from leaking vessels

Clinton, J.H.

1994-09-01

An interactive computer code for estimating the rate of release of any one of several materials from a leaking tank or broken pipe leading from a tank is presented. It is generally assumed that the material in the tank is liquid. Materials included in the data base are acetonitrile, ammonia, carbon tetrachloride, chlorine, chlorine trifluoride, fluorine, hydrogen fluoride, nitric acid, nitrogen tetroxide, sodium hydroxide, sulfur hexafluoride, sulfuric acid, and uranium hexafluoride. Materials that exist only as liquid and/or vapor over expected ranges of temperature and pressure can easily be added to the data base file. The Fortran source code for LEAK and the data file are included with this report.

5. Evaluating High Release Rate MCH (3-Methylcyclohex-2-en-1-one) Treatments for Reducing Dendroctonus pseudotsugae (Coleoptera: Curculionidae) Infestations.

Brookes, Harrison M; Ross, Darrell W; Strand, Tara M; Thistle, Harold W; Ragenovich, Iral R; Lowrey, Laura L

2016-12-01

Current recommendations for applying the antiaggregation pheromone 3-methylcyclohex-2-en-1-one (MCH) to protect live trees from Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, infestation are to space individual passive releasers (MCH bubble capsules) on a 12- by 12-m grid throughout areas to be protected. Previous field studies and a theoretical study using a puff dispersion model to predict pheromone concentrations have shown that releasers emitting higher rates of MCH spaced farther apart may be as effective as the established standard treatment. During 2012 and 2013, we tested higher release rates of MCH at correspondingly wider spacings to keep the total amount of MCH released per unit area equal in all treatments. In 2012 near Challis, ID, treatments included the established standard release rate and spacing, four and six times the standard release rate at correspondingly wider spacings, and an untreated control. In 2013 near Ketchum, ID, treatments included the established standard release rate and spacing, five and seven times the standard release rate at correspondingly wider spacings, and an untreated control. Results from both years indicated that all MCH treatments were equally effective in reducing Douglas-fir beetle infestation. Using higher release rate formulations at wider spacings will reduce labor costs of installing MCH treatments, and, in cases where it is necessary, retrieving the releasers as well. In addition to reducing labor costs, the revised treatment protocol may increase the feasibility of treating areas that currently may not be possible due to treatment costs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

6. Evaluating release alternatives for a long-lived bird species under uncertainty about long-term demographic rates

Moore, Clinton T.; Converse, Sarah J.; Folk, Martin J.; Runge, Michael C.; Nesbitt, Stephen A.

2012-01-01

The release of animals to reestablish an extirpated population is a decision problem that is often attended by considerable uncertainty about the probability of success. Annual releases of captive-reared juvenile Whooping Cranes (Grus americana) were begun in 1993 in central Florida, USA, to establish a breeding, non-migratory population. Over a 12-year period, 286 birds were released, but by 2004, the introduced flock had produced only four wild-fledged birds. Consequently, releases were halted over managers' concerns about the performance of the released flock and uncertainty about the efficacy of further releases. We used data on marked, released birds to develop predictive models for addressing whether releases should be resumed, and if so, under what schedule. To examine the outcome of different release scenarios, we simulated the survival and productivity of individual female birds under a baseline model that recognized age and breeding-class structure and which incorporated empirically estimated stochastic elements. As data on wild-fledged birds from captive-reared parents were sparse, a key uncertainty that confronts release decision-making is whether captive-reared birds and their offspring share the same vital rates. Therefore, we used data on the only population of wild Whooping Cranes in existence to construct two alternatives to the baseline model. The probability of population persistence was highly sensitive to the choice of these three models. Under the baseline model, extirpation of the population was nearly certain under any scenario of resumed releases. In contrast, the model based on estimates from wild birds projected a high probability of persistence under any release scenario, including cessation of releases. Therefore, belief in either of these models suggests that further releases are an ineffective use of resources. In the third model, which simulated a population Allee effect, population persistence was sensitive to the release decision

7. Study on the optimum pheromone release rate for attraction of Chilo suppressalis (Lepidoptera: Pyralidae).

Vacas, Sandra; Alfaro, Cristina; Navarro-Llopis, Vicente; Zarzo, Manuel; Primo, Jaime

2009-06-01

Traditional chemical control against Chilo suppressalis Walker is currently being replaced in Spain by new methods based on pheromones. A key step to improve the efficacy of these methods is the determination of the optimum pheromone release rate, which is still uncertain for this pest. In this work, the pheromone release profile and the field performance of a new mesoporous dispenser was compared with a standard commercial dispenser. For this purpose, pheromone loads were extracted from field-aged dispensers and quantified by gas chromatography with flame ionization detector. In addition, a field trial was carried out with traps baited with one, two, or three mesoporous dispensers per trap, as well as with traps containing one standard dispenser. We found that the highest number of field catches did not correspond to the highest pheromone emission rate, which suggests a repellent effect of the insect if the emission is excessive. The results suggest that the attractant activity was maximized by emitting approximately 34 microg/d. The efficacy of the mesoporous dispenser and its possible improvements are discussed.

8. Energy-release rate and mode mixity of face/core debonds in sandwich beams

Kardomateas, George A.; Berggreen, Christian; Carlsson, Leif A.

2013-01-01

Closed-form algebraic expressions for the energy-release rate and the mode mixity are obtained for a debonded sandwich (trimaterial). The most general case of an "asymmetric" sandwich is considered (i.e., the bottom face sheet not necessarily of the same material or thickness as the top facesheet......).The energy-release rate is obtained by use of the J-integral,and the expression is derived interms of the forces and moments at the debond section.Regarding the mode mixity, a closed-form expression is derived in terms of the geometry, material, and applied loading, and it is proven that, in the trimaterial...... case, just as in the bimaterial case, the mode mixity can be obtained in terms of a single scalar quantityω,which is independent of loading;theωvalue for a particular geometry and material can be extracted from a numerical solution for one loading combination. Thus, this analysis extends the existing...

9. Magnetic Reconnection Rates and Energy Release in a Confined X-class Flare

Veronig, A M

2015-01-01

We study the energy-release process in the confined X1.6 flare that occurred on 22 October 2014 in AR 12171. Magnetic-reconnection rates and reconnection fluxes are derived from three different data sets: space-based data from the Atmospheric Imaging Assembly (AIA) 1600 {\\AA} filter onboard the Solar Dynamics Observatory (SDO) and ground-based H$\\alpha$ and Ca II K filtergrams from Kanzelh\\"ohe Observatory. The magnetic-reconnection rates determined from the three data sets all closely resemble the temporal profile of the hard X-rays measured by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), which are a proxy for the flare energy released into high-energy electrons. The total magnetic-reconnection flux derived lies between $4.1 \\times 10^{21}$ Mx (AIA 1600 {\\AA}) and $7.9 \\times 10^{21}$ Mx (H$\\alpha$), which corresponds to about 2 to 4% of the total unsigned flux of the strong source AR. Comparison of the magnetic-reconnection flux dependence on the GOES class for 27 eruptive events collected fr...

10. Unexpectedly high catch-and-release rates in European marine recreational fisheries: implications for science and management

Ferter, Keno; Weltersbach, Marc Simon; Strehlow, Harry Vincent;

2013-01-01

Unexpectedly high catch-and-release rates in European marine recreational fisheries: implications for science and management. – ICES Journal of Marine Science, 70: .While catch-and-release (C&R) is a well-known practice in several European freshwater recreational fisheries, studies on the magnitu...

11. A smoothed stochastic earthquake rate model considering seismicity and fault moment release for Europe

Hiemer, S.; Woessner, J.; Basili, R.; Danciu, L.; Giardini, D.; Wiemer, S.

2014-08-01

We present a time-independent gridded earthquake rate forecast for the European region including Turkey. The spatial component of our model is based on kernel density estimation techniques, which we applied to both past earthquake locations and fault moment release on mapped crustal faults and subduction zone interfaces with assigned slip rates. Our forecast relies on the assumption that the locations of past seismicity is a good guide to future seismicity, and that future large-magnitude events occur more likely in the vicinity of known faults. We show that the optimal weighted sum of the corresponding two spatial densities depends on the magnitude range considered. The kernel bandwidths and density weighting function are optimized using retrospective likelihood-based forecast experiments. We computed earthquake activity rates (a- and b-value) of the truncated Gutenberg-Richter distribution separately for crustal and subduction seismicity based on a maximum likelihood approach that considers the spatial and temporal completeness history of the catalogue. The final annual rate of our forecast is purely driven by the maximum likelihood fit of activity rates to the catalogue data, whereas its spatial component incorporates contributions from both earthquake and fault moment-rate densities. Our model constitutes one branch of the earthquake source model logic tree of the 2013 European seismic hazard model released by the EU-FP7 project Seismic HAzard haRmonization in Europe' (SHARE) and contributes to the assessment of epistemic uncertainties in earthquake activity rates. We performed retrospective and pseudo-prospective likelihood consistency tests to underline the reliability of our model and SHARE's area source model (ASM) using the testing algorithms applied in the collaboratory for the study of earthquake predictability (CSEP). We comparatively tested our model's forecasting skill against the ASM and find a statistically significant better performance for

12. The Effect of Synthetic Brine Constituents on the Rate of Arsenic Release from Arsenopyrite

Parthasarathy, H.; Dzombak, D. A.; Karamalidis, A.

2013-12-01

Geologic carbon dioxide storage (GCS) in deep saline sedimentary formations is a potential method for mitigating increased levels of atmospheric CO2. Injection of CO2 in those formations may induce dissolution of reservoir minerals. Leakage of CO2-saturated brines and native brines could impact overlying drinking water aquifers by contaminating them with toxic constituents. Of particular concern is the effect of CO2 on the rates of dissolution of arsenic and other toxic metals from reservoir minerals. The most common pure phase arsenic mineral in sedimentary geologic formations is arsenopyrite (FeAsS). Natural brines have high salinities (up to 7M), with high concentrations of Na+, Ca2+, Mg2+ and K+. The focus of this study is to examine the effect of brine components on the dissolution rate of arsenic from arsenopyrite. A small-scale flow-through column system was constructed for this purpose and is being used to measure arsenic release rates from arsenopyrite. Influent solutions of NaCl, CaCl2, and MgCl2 at equal ionic strengths were used to examine the effect of the cationic species. A cleaning procedure to remove prior surface oxidation on the surface of the arsenopyrite particles was also developed. Preliminary results with NaCl and CaCl2 at an ionic strength of 0.011M indicate that the rate of dissolution of arsenic is dependent on the cationic species but independent of ionic strength.

13. Effect of flow rate and lead/copper pipe sequence on lead release from service lines.

Cartier, Clément; Arnold, Roger B; Triantafyllidou, Simoni; Prévost, Michèle; Edwards, Marc

2012-09-01

A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present.

14. Increased survival rate by local release of diclofenac in a murine model of recurrent oral carcinoma

Will OM

2016-10-01

Full Text Available Olga Maria Will,1,* Nicolai Purcz,2,* Athena Chalaris,3 Carola Heneweer,4,5 Susann Boretius,1 Larissa Purcz,2 Lila Nikkola,6 Nureddin Ashammakhi,6 Holger Kalthoff,7 Claus-Christian Glüer,1 Jörg Wiltfang,2 Yahya Açil,2 Sanjay Tiwari1 1Section Biomedical Imaging, Clinic for Radiology and Neuroradiology, MOIN CC, 2Department of Oral and Maxillofacial Surgery, University Hospital Schleswig-Holstein, 3Institute of Biochemistry, Christian-Albrechts-Universität zu Kiel, 4Clinic for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Kiel, 5Institute for Diagnostic and Interventional Radiology, University Hospital Cologne, Cologne, Germany; 6Department of Biomedical Engineering, Tampere University of Technology, Tampere, Finland; 7Institute for Experimental Cancer Research, University Hospital Schleswig-Holstein, Kiel, Germany *These authors contributed equally to this work Abstract: Despite aggressive treatment with radiation and combination chemotherapy following tumor resection, the 5-year survival rate for patients with head and neck cancer is at best only 50%. In this study, we examined the therapeutic potential of localized release of diclofenac from electrospun nanofibers generated from poly(d,l-lactide-co-glycolide polymer. Diclofenac was chosen since anti-inflammatory agents that inhibit cyclooxygenase have shown great potential in their ability to directly inhibit tumor growth as well as suppress inflammation-mediated tumor growth. A mouse resection model of oral carcinoma was developed by establishing tumor growth in the oral cavity by ultrasound-guided injection of 1 million SCC-9 cells in the floor of the mouth. Following resection, mice were allocated into four groups with the following treatment: 1 no treatment, 2 implanted scaffolds without diclofenac, 3 implanted scaffolds loaded with diclofenac, and 4 diclofenac given orally. Small animal ultrasound and magnetic resonance imaging were utilized for longitudinal

15. The Effects of Different Amounts of Controlled Release Fertilizer on the Root Growth and the Filling Rate in Winter Wheat

Meng Li

2014-03-01

Full Text Available In order to increase the fertilizer use efficiency and yield in winter wheat, the effects of controlled release fertilizer on the root growth and the filling rate in winter wheat by applying different amounts of controlled release fertilizer had been studied in open field. The results indicated that conventional complex fertilizer and controlled release fertilizer could cause corresponding changes of the wheat root activity, dry root weight, root-shoot ratio and filling rate, but the fertilizer of conventional fertilizer performed in the pre-stage significantly, controlled release fertilizer performed in the middle and late stage gradually. So mixing conventional fertilizer with controlled release fertilizer can ensure the nutrient supply of whole growth and development of wheat to explore the most appropriate collocation dosage. This will make fertilizer and economic benefits achieve the best.

16. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

N. Cai

2012-01-01

Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

17. Global rates of mantle serpentinization and H2 release at oceanic transform faults

Ruepke, Lars; Hasenclever, Joerg

2017-04-01

The cycling of seawater through the ocean floor is the dominant mechanism of biogeochemical exchange between the solid earth and the global ocean. Crustal fluid flow appears to be typically associated with major seafloor structures, and oceanic transform faults (OTF) are one of the most striking yet poorly understood features of the global mid-ocean ridge systems. Fracture zones and transform faults have long been hypothesized to be sites of substantial biogeochemical exchange between the solid Earth and the global ocean. This is particularly interesting with regard to the ocean biome. Deep ocean ecosystems constitute 60% of it but their role in global ocean biogeochemical cycles is much overlooked. There is growing evidence that life is supported by chemosynthesis at hydrothermal vents but also in the crust, and therefore this may be a more abundant process than previously thought. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting as it is also a mechanism of abiotic hydrogen and methane formation. Interestingly, a quantitative global assessment of mantle serpentinization at oceanic transform faults in the context of the biogeochemical exchange between the seafloor and the global ocean is still largely missing. Here we present the results of a set of 3-D thermo-mechanical model calculations that investigate mantle serpentinization at OTFs for the entire range of globally observed slip rates and fault lengths. These visco-plastic models predict the OTF thermal structure and the location of crustal-scale brittle deformation, which is a prerequisite for mantle serpentinization to occur. The results of these simulations are integrated with information on the global distribution of OTF lengths and slip rates yielding global estimates on mantle serpentinization and associated H2 release. We find that OTFs are potentially sites of intense crustal fluid flow and are in terms of H2 release

18. Adhesive-Bonded Composite Joint Analysis with Delaminated Surface Ply Using Strain-Energy Release Rate

Chadegani, Alireza; Yang, Chihdar; Smeltzer, Stanley S. III

2012-01-01

This paper presents an analytical model to determine the strain energy release rate due to an interlaminar crack of the surface ply in adhesively bonded composite joints subjected to axial tension. Single-lap shear-joint standard test specimen geometry with thick bondline is followed for model development. The field equations are formulated by using the first-order shear-deformation theory in laminated plates together with kinematics relations and force equilibrium conditions. The stress distributions for the adherends and adhesive are determined after the appropriate boundary and loading conditions are applied and the equations for the field displacements are solved. The system of second-order differential equations is solved to using the symbolic computation tool Maple 9.52 to provide displacements fields. The equivalent forces at the tip of the prescribed interlaminar crack are obtained based on interlaminar stress distributions. The strain energy release rate of the crack is then determined by using the crack closure method. Finite element analyses using the J integral as well as the crack closure method are performed to verify the developed analytical model. It has been shown that the results using the analytical method correlate well with the results from the finite element analyses. An attempt is made to predict the failure loads of the joints based on limited test data from the literature. The effectiveness of the inclusion of bondline thickness is justified when compared with the results obtained from the previous model in which a thin bondline and uniform adhesive stresses through the bondline thickness are assumed.

19. Quantification of Kinetic Rate Law Parameters of Uranium Release from Sodium Autunite as a Function of Aqueous Bicarbonate Concentrations

Gudavalli, Ravi; Katsenovich, Yelena; Wellman, Dawn M.; Lagos, Leonel; Tansel, Berrin

2013-09-05

ABSTRACT: Hydrogen carbonate is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, hydrogen carbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous hydrogen carbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through (SPTF) experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005-0.003 M) under the pH range of 6-11 and temperatures of 5-60oC. Consistent with the results of previous investigation, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature; but were strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited 370 fold increases relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As pH increased from 6 to 11, activation energy values were observed to decrease from 29.94 kJ mol-1 to 13.07 kJ mol-1. The calculated activation energies suggest a surface controlled dissolution mechanism.

20. Static and dynamic strain energy release rates in toughened thermosetting composite laminates

Cairns, Douglas S.

1992-01-01

In this work, the static and dynamic fracture properties of several thermosetting resin based composite laminates are presented. Two classes of materials are explored. These are homogeneous, thermosetting resins and toughened, multi-phase, thermosetting resin systems. Multi-phase resin materials have shown enhancement over homogenous materials with respect to damage resistance. The development of new dynamic tests are presented for composite laminates based on Width Tapered Double Cantilevered Beam (WTDCB) for Mode 1 fracture and the End Notched Flexure (ENF) specimen. The WTDCB sample was loaded via a low inertia, pneumatic cylinder to produce rapid cross-head displacements. A high rate, piezo-electric load cell and an accelerometer were mounted on the specimen. A digital oscilloscope was used for data acquisition. Typical static and dynamic load versus displacement plots are presented. The ENF specimen was impacted in three point bending with an instrumented impact tower. Fracture initiation and propagation energies under static and dynamic conditions were determined analytically and experimentally. The test results for Mode 1 fracture are relatively insensitive to strain rate effects for the laminates tested in this study. The test results from Mode 2 fracture indicate that the toughened systems provide superior fracture initiation and higher resistance to propagation under dynamic conditions. While the static fracture properties of the homogeneous systems may be relatively high, the apparent Mode 2 dynamic critical strain energy release rate drops significantly. The results indicate that static Mode 2 fracture testing is inadequate for determining the fracture performance of composite structures subjected to conditions such as low velocity impact. A good correlation between the basic Mode 2 dynamic fracture properties and the performance is a combined material/structural Compression After Impact (CAI) test is found. These results underscore the importance of

1. Determination of Nitrogen, Phosphorus, and Potassium Release Rates of Slow- and Controlled-Release Fertilizers: Single-Laboratory Validation, First Action 2015.15.

Thiex, Nancy

2016-01-01

A previously validated method for the determination of nitrogen release patterns of slow- and controlled-release fertilizers (SRFs and CRFs, respectively) was submitted to the Expert Review Panel (ERP) for Fertilizers for consideration of First Action Official Method(SM) status. The ERP evaluated the single-laboratory validation results and recommended the method for First Action Official Method status and provided recommendations for achieving Final Action. The 180 day soil incubation-column leaching technique was demonstrated to be a robust and reliable method for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and the results were only slightly affected by variations in environmental factors such as microbial activity, soil moisture, temperature, and texture. The release of P and K were also studied, but at fewer replications than for N. Optimization experiments on the accelerated 74 h extraction method indicated that temperature was the only factor found to substantially influence nutrient-release rates from the materials studied, and an optimized extraction profile was established as follows: 2 h at 25°C, 2 h at 50°C, 20 h at 55°C, and 50 h at 60°C.

2. Laboratory experiment to determine phosphate release rates from sediments of a formerly oligotrophic lake (Silbersee, Cuxhaven)

Elmarami, Hatem; Greskowiak, Janek; Hamann, Enrico; Massmann, Gudrun

2016-04-01

The Silbersee is a small, formerly oligotrophic lake in northwestern Germany which still contains rare character species for oligotrophic lakes (Isoëtes lacustris, Littorella uniflora) threatened by eutrophication. It was suspected that the lake sediments and the redox conditions in the hypolimnon play an important role with regard to eutrophication, potentially releasing phosphorus (P) into the water column. This was the motivation to conduct experiments to estimate the release rate of phosphorus into the lake. It had been noted that the P concentrations in the bottom water were higher during summer in the stagnation phase, when conditions turned sulfidic. Eight sediment cores were taken with a Mondsee-corer (manufactured by UWITEC) at different sites of the lake. The thickness of the sediment within the cores ranged from 15cm to 35 cm and were overlying by approximately 40cm of lake water water. The headspace was approximately 10cm. The cores were stored in a fridge first under oxic, then under anoxic conditions as observed in the lake bottom water in the different seasons. Redox conditions were maintained by bubbling with oxygen and nitrogen gas during the respective time periods. During the experiment, the temperature was held constant to match the water temperature measured at the bottom of the lake (~ 7±1°C). Concentrations of total phosphorus (TP) and dissolved phosphorus (DP), iron (Fe) and dissolved oxygen (DO) as well as pH were measured under oxic and anoxic conditions in the water column. The results showed that TP, DP and Fe concentrations were higher under anoxic conditions than under oxic conditions. The observed increase of phosporous in the water column during the anoxic phase was presumably a result of (i) reductive Fe-oxides dissolution and the corresponding loss of sorption sites and (ii) desorption of phosphorous via surface complexation reactions due to pH changes during the experiment.

3. Evaluation of in vitro release rate and in vivo absorption characteristics of four metoprolol tartrate immediate-release tablet formulations.

Rekhi, G S; Eddington, N D; Fossler, M J; Schwartz, P; Lesko, L J; Augsburger, L L

1997-02-01

The purpose of this investigation was to examine the impact of formulation and process changes on dissolution and bioavailability/bioequivalency of metoprolol tartrate tablets manufactured using a high-shear granulation process. A half-factorial (2(4-1), Res IV) design was undertaken to study the selected formulation and processing variables during scale-up. Levels and ranges for excipients and processing changes studied represented level 2 or greater changes as indicated by the SUPAC-IR Guidance. Blend and tableting properties were evaluated. Changes in sodium starch glycolate and magnesium stearate levels, and the order of addition microcrystalline cellulose (intra- vs. extragranular) were significant only in affecting percent drug released (Q) in 5, 10, and 15 min. Statistical analysis of data showed no significant curvature. No interaction effects were found to be statistically significant. To examine the impact of formulation and processing variables on in vivo absorption, three batches were selected for a bioavailability study based on their dissolution profiles. Subjects received four metoprolol treatments (Lopressor, slow-, medium-, and fast-dissolving formulations) separated by 1 week according to a randomized crossover design. After an overnight fast, subjects were administered one tablet (100 mg), blood samples were collected over 24 hr and plasma samples were analyzed. The formulations were found to be bioequivalent with respect to the log Cmax and log AUC0-infinity. The results of this study suggest that: (i) bioavailability/bioequivalency studies may not be necessary for metoprolol tartrate and perhaps other class 1 drugs after level 2 type changes and (ii) in vitro dissolution tests may be used to show bioequivalence of metoprolol formulations with processing or formulation changes within the specified level 2 ranges for the equipment examined.

4. Enhanced absorption of the poorly soluble drug fenofibrate by tuning its release rate from ordered mesoporous silica.

Van Speybroeck, Michiel; Mellaerts, Randy; Mols, Raf; Thi, Thao Do; Martens, Johan Adriaan; Van Humbeeck, Jan; Annaert, Pieter; Van den Mooter, Guy; Augustijns, Patrick

2010-12-23

The aim of the present study was to evaluate the effect of release rate from ordered mesoporous silica materials on the rate and extent of absorption of the poorly soluble drug fenofibrate. Three ordered mesoporous silica materials with different pore diameter (7.3 nm, 4.4 nm and 2.7 nm) were synthesized and loaded with fenofibrate via impregnation. Release experiments were conducted under sink conditions and under supersaturating conditions in biorelevant media, simulating the fasted and the fed state. Subsequently, all silica-based formulations were evaluated in vivo (rat model). The release experiments under sink conditions indicated a clear increase in release rate with increasing pore size. However, under supersaturating conditions (FaSSIF), the, pharmaceutical performance (in terms of both the degree and duration of supersaturation), increased with decreasing pore size. The same trend was observed in vivo (fasted state): the area under the plasma concentration-time profile amounted to 102 ± 34 μMh, 86 ± 19 μMh and 20 ± 13 μMh for the materials with pore diameter of 2.7 nm, 4.4 nm and 7.3 nm, respectively. The results of this, study demonstrate that a decrease in drug release rate - and thus, a decrease of the rate at which supersaturation is created - is beneficial to the absorption of fenofibrate. Copyright © 2010 Elsevier B.V. All rights reserved.

5. Effective rates of heavy metal release from alkaline wastes--quantified by column outflow experiments and inverse simulations.

Wehrer, Markus; Totsche, Kai Uwe

2008-10-23

Column outflow experiments operated at steady state flow conditions do not allow the identification of rate limited release processes. This requires an alternative experimental methodology. In this study, the aim was to apply such a methodology in order to identify and quantify effective release rates of heavy metals from granular wastes. Column experiments were conducted with demolition waste and municipal waste incineration (MSWI) bottom ash using different flow velocities and multiple flow interruptions. The effluent was analyzed for heavy metals, DOC, electrical conductivity and pH. The breakthrough-curves were inversely modeled with a numerical code based on the advection-dispersion equation with first order mass-transfer and nonlinear interaction terms. Chromium, Copper, Nickel and Arsenic are usually released under non-equilibrium conditions. DOC might play a role as carrier for those trace metals. By inverse simulations, generally good model fits are derived. Although some parameters are correlated and some model deficiencies can be revealed, we are able to deduce physically reasonable release-mass-transfer time scales. Applying forward simulations, the parameter space with equifinal parameter sets was delineated. The results demonstrate that the presented experimental design is capable of identifying and quantifying non-equilibrium conditions. They show also that the possibility of rate limited release must not be neglected in release and transport studies involving inorganic contaminants.

6. Inverse identification of the release location, temporal rates, and sensor alarming time of an airborne pollutant source.

Zhang, T; Zhou, H; Wang, S

2015-08-01

With an accidental release of an airborne pollutant, it is always critical to know where, when, and how the pollutant has been released. Then, emergency measures can be scientifically advised to prevent any possible harm. This investigation proposes an inverse model to identify the release location, the temporal rate profile, and the sensor alarming time from the start of a pollutant release. The first step is to implement the inverse operation to the cause-effect matrix to obtain the release rate profiles for discrete candidate scenarios with concentration information provided by one sensor. The second step is to interpret the occurrence probability of each solution in the first step with the Bayesian model by matching the concentration at the other sensor. The proposed model was applied to identify a single pollutant source in a two-dimensional enclosure using measurement data and in a three-dimensional aircraft cabin with simulated data. The results show that the model is able to correctly determine the pollutant source location, the temporal rate profile, and the sensor alarming time. The known conditions for input into the inverse model include a steady flow field and the valid temporal concentrations at two different locations. The proposed inverse model can tell where, when, and how a gaseous pollutant has been accidently released based on the monitoring concentrations measured by two sensors. This methodology can be useful for providing emergency protection to indoor occupants. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

7. EXPERIMENTAL STUDY ON PREMIX COMBUSTION AT ISOSCELES TRIANGLE TYPE RATE OF HEAT RELEASE FOR SQUISH TYPE COMBUSTION CHAMBER

2001-01-01

This paper presents a theory on premix fuel combustion at nearisosceles triangle type rate of heat release,describes the measures taken for the combustion system,points out its many theoretical advantages,and that it can solve effectively the problems of rough running,fuel consumption and exhaust emission.Two squish lip type combustion chambers are designed to match separately with multiple holes injector and conical spray type injector in order to achieve premix combustion at near isosceles triangle type rate of heat release.Experimental studies on two single cylinder diesel engines showed that premix combustion at isosceles triangle type rate of heat release resulted in longer ignition delay period,larger amount of fuel injected into cylinder during the ignition delay period,lower maximum pressure,better fuel economy,and better exhaust emission.

8. Assessment of survival rates and reproductive success of captive bred milky stork released at Kuala Gula Bird Sanctuary, Perak

Faiq, H.; Safie, M. Y.; Shukor, M. N.

2016-11-01

A release programme of captive bred Milky Storks was initiated to increase population size in the wild. Population size depends on the survival rate and breeding success of individuals in the population. Among factors that affect survival rate and breeding success are population age class and sex ratio. The main objective of this study was to estimate the survival rate of Mycteria cinerea that has been released in Kuala Gula Bird Sanctuary since 2007. The estimation of the survival rate was done across gender and age class. This study was conducted in 2012 at Kuala Gula Bird Sanctuary. The presence of M. cinerea individuals were recorded at the sanctuary and identified to background information, such as date of birth, gender and date of release. Females of M. cinerea were estimated to have a higher survival rate (30.0%) than male (16.7%). Across gender, each individual was assigned into 4 different age classes, namely less than 1 year, between 1 and 2 years, between 2 and 3 years, and more than 3 years. The survival rate of individuals less than 1 year was about 50%, between 1 and 2 years was 25%, between 2 and 3 years was 9.1%, and more than 3 years was 0%. This study was intended to facilitate future release programmeme on which gender and age class to emphasize.

9. Rates and mechanisms of radioactive release and retention inside a waste disposal canister - in Can Processes

Oversby, V.M. (ed.) [and others

2003-10-01

the system that will not be present under long term disposal conditions. A simulation of long-term conditions can be done using uranium dioxide that contains a short-lived isotope of uranium, but this will not include the effects of fission product and higher actinide elements on the behaviour of the spent fuel. We designed a project that had as its objective to improve the scientific understanding of the processes that control release of radioactive species from spent fuel inside a disposal canister and the chemical changes in those species that might limit release of radioactivity from the canister. If the mechanisms that control dissolution of the fuel matrix, including self-irradiation effects, can be clarified, a more realistic assessment of the long-term behaviour of spent fuel under disposal conditions can be made. By removing uncertainties concerning waste form performance, a better assessment of the individual and collective role of the engineered barriers can be made. To achieve the overall objective of the project, the following scientific and technical objectives were set. 1. Measure the actual rate of matrix dissolution of uranium dioxide under oxidising and reducing conditions. 2. Measure the effect of alpha radiolysis on the dissolution rate of uranium dioxide under oxidising and reducing conditions. 3. Measure the dissolution rate of the matrix material of spent fuel and thereby determine the additional effects of beta and gamma radiation on uranium dioxide dissolution rate under oxidising and reducing conditions. 4. Measure the ability of actively corroding iron to reduce oxidised U(VI) to U(IV) when U is present as the complex ion uranyl carbonate. 5. Measure the rate of reduction of Np(V) species in the presence of actively corroding iron. 6. Calculate the expected equilibrium and steady state concentrations of U under the conditions of the experiments used for meeting objectives 1 through 3 and compare the calculated results with those measured in

10. Effects of Time-Release Caffeine Containing Supplement on Metabolic Rate, Glycerol Concentration and Performance

Adam M. Gonzalez, Jay R. Hoffman, Adam J. Wells, Gerald T. Mangine, Jeremy R. Townsend, Adam R. Jajtner, Ran Wang, Amelia A. Miramonti, Gabriel J. Pruna, Michael B. LaMonica, Jonathan D. Bohner, Mattan W. Hoffman, Leonardo P. Oliveira, David H. Fukuda, Maren S. Fragala, Jeffrey R. Stout

2015-06-01

Full Text Available This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF versus a regular caffeine capsule (CAF and a placebo (PL. Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05 in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042 in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86 or metabolic measures (p = 0.17-0.91. Physical reaction time was significantly improved for CAF at hour 5 (p=0.01 compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively and over the 8-hour period (p = 0.04 and p = 0.001, respectively compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004. TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures.

11. The surface-forming energy release rate based fracture criterion for elastic-plastic crack propagation

Xiao, Si; Wang, He-Ling; Liu, Bin; Hwang, Keh-Chih

2015-11-01

The J-integral based criterion is widely used in elastic-plastic fracture mechanics. However, it is not rigorously applicable when plastic unloading appears during crack propagation. One difficulty is that the energy density with plastic unloading in the J-integral cannot be defined unambiguously. In this paper, we alternatively start from the analysis on the power balance, and propose a surface-forming energy release rate (ERR), which represents the energy available for separating the crack surfaces during the crack propagation and excludes the loading-mode-dependent plastic dissipation. Therefore the surface-forming ERR based fracture criterion has wider applicability, including elastic-plastic crack propagation problems. Several formulae are derived for calculating the surface-forming ERR. From the most concise formula, it is interesting to note that the surface-forming ERR can be computed using only the stress and deformation of the current moment, and the definition of the energy density or work density is avoided. When an infinitesimal contour is chosen, the expression can be further simplified. For any fracture behaviors, the surface-forming ERR is proven to be path-independent, and the path-independence of its constituent term, so-called Js-integral, is also investigated. The physical meanings and applicability of the proposed surface-forming ERR, traditional ERR, Js-integral and J-integral are compared and discussed. Besides, we give an interpretation of Rice paradox by comparing the cohesive fracture model and the surface-forming ERR based fracture criterion.

12. Scanning electrochemical microscopy of metallic biomaterials: reaction rate and ion release imaging modes.

Gilbert, J L; Smith, S M; Lautenschlager, E P

1993-11-01

The Scanning Electrochemical Microscope (SECM) is a nonoptical scanning microscopic instrument capable of imaging highly localized electrical currents associated with charge transfer reactions on metallic biomaterials surfaces. The SECM operates as an aqueous electrochemical cell under bipotentiostatic control with a microelectrode and sample independently biased as working electrodes. Microelectrode current and position is recorded as it is scanned very near a metallurgically polished planar sample surface. To date, the SECM has imaged metallic biomaterials surfaces in oxygen reaction rate imaging (ORRI) and ion release and deposition imaging (IRDI) modes. In ORRI, sample and microelectrode are biased at sufficiently negative potentials to reduce absorbed oxygen. As the microelectrode scans areas of active oxygen reduction, localized diffusion fields with decreased oxygen solution concentrations are encountered and resultant decrements in microelectrode current are observed. In IRDI mode the sample is positively biased and the microelectrode is negatively biased. The microelectrode detects anodic dissolution products with highest currents being observed over the most active areas. Performance of the SECM has been evaluated on Ni minigrids, gamma-1 Hg-Ag dental amalgam crystals, and sintered beads of Co-Cr-Mo alloy which represent significantly different geometries and corrosion processes to help demonstrate the potential of this instrument. The SECM is a valuable tool for imaging microelectrochemical processes on the surfaces of metallurgically polished metallic biomaterials samples and a wide variety of other surfaces of biological interest where charge transfer reactions occur. The SECM allows selective biasing of metallic biomaterials surfaces and Faradaic reactions can be selectively imaged while the surface is in the active, passive, or transpassive state.

13. Multiple release layer study of the intrinsic lateral etch rate of the epitaxial lift-off process

Voncken, M.M.J.; Schermer, J.J.; Bauhuis, G.J.; Mulder, P.; Larsen, P.K.

2004-01-01

The lateral etch rate of AlGaAs in HF in the 'Epitaxial Lift-Off' (ELO) process consists of two parts, an intrinsic and a radius-induced part. The intrinsic part is studied with a new approach in which multiple release layers are introduced in one sample. By letting an essential ELO process paramete

14. Attraction of agrilus planipennis fairmaire (Coleoptera: Buprestidae) to a volatile pheromone: effects of release rate, host volatile and trap placement

Attraction of emerald ash borer, Agrilus planipennis Fairmaire, to a volatile pheromone was demonstrated in three field experiments using baited green sticky traps. A dose-response curve was generated for male A. planipennis to increasing release rates of (3Z)-dodecen-12-olide, (3Z)-lactone, in com...

15. Effects of gonadotropin-releasing hormone administration or a controlled internal drug-releasing insert after timed artificial insemination on pregnancy rates of dairy cows

Jeong, Jae Kwan; Choi, In Soo; Kang, Hyun Gu; Hur, Tai Young

2016-01-01

This study investigated the effects of gonadotrophin-releasing hormone (GnRH) administration (Experiment 1) and a controlled internal drug-releasing (CIDR) insert (Experiment 2) after timed artificial insemination (TAI) on the pregnancy rates of dairy cows. In Experiment 1, 569 dairy cows that underwent TAI (day 0) following short-term synchronization with prostaglandin F2α were randomly allocated into two groups: no further treatment (control, n = 307) or injection of 100 µg of gonadorelin on day 5 (GnRH, n = 262). In Experiment 2, 279 dairy cows that underwent TAI (day 0) following Ovsynch were randomly allocated into two groups: no further treatment (control, n = 140) or CIDR insert treatment from days 3.5 to 18 (CIDR, n = 139). The probability of pregnancy following TAI did not differ between the GnRH (34.4%) and control (31.6%, p > 0.05) groups. However, the probability of pregnancy following TAI was higher (odds ratio: 1.74, p < 0.05) in the CIDR group (51.1%) than in the control group (39.3%). Overall, CIDR insert treatment at days 3.5 to 18 increased pregnancy rates relative to non-treated controls, whereas a single GnRH administration on day 5 did not affect the pregnancy outcomes of dairy cows. PMID:27030200

16. Groundwater flow analysis and dose rate estimates from releases to wells at a coastal site

Kattilakoski, E.; Suolanen, V. [VTT Energy, Espoo (Finland)

2000-09-01

{sup 3}/a. Due to the placing of the shallow wells in the discharge areas, the dilution calculated in the shallow well was shown to be close to that calculated in the deep well. In conservative considerations the value around 90 000 m{sup 3}/a can be regarded as a representative expectation value of the effective dilution of the well. This dilution volume value was also suggested by the most realistic modelling approach of the groundwater flow analysis. It was used as basis when calculating the nuclide specific dose conversion factors (DCF's) for the drinking water pathway. The DCF's were calculated for unit release rates (1 Bq/a) and the assumed water consumption rate was 2 litres/day. (orig.)

17. Electrospun Polymer Blend Nanofibers for Tunable Drug Delivery: The Role of Transformative Phase Separation on Controlling the Release Rate.

Tipduangta, Pratchaya; Belton, Peter; Fábián, László; Wang, Li Ying; Tang, Huiru; Eddleston, Mark; Qi, Sheng

2016-01-01

Electrospun fibrous materials have a wide range of biomedical applications, many of them involving the use of polymers as matrices for incorporation of therapeutic agents. The use of polymer blends improves the tuneability of the physicochemical and mechanical properties of the drug loaded fibers. This also benefits the development of controlled drug release formulations, for which the release rate can be modified by altering the ratio of the polymers in the blend. However, to realize these benefits, a clear understanding of the phase behavior of the processed polymer blend is essential. This study reports an in depth investigation of the impact of the electrospinning process on the phase separation of a model partially miscible polymer blend, PVP K90 and HPMCAS, in comparison to other conventional solvent evaporation based processes including film casting and spin coating. The nanoscale stretching and ultrafast solvent removal of electrospinning lead to an enhanced apparent miscibility between the polymers, with the same blends showing micronscale phase separation when processed using film casting and spin coating. Nanoscale phase separation in electrospun blend fibers was confirmed in the dry state. Rapid, layered, macroscale phase separation of the two polymers occurred during the wetting of the fibers. This led to a biphasic drug release profile from the fibers, with a burst release from PVP-rich phases and a slower, more continuous release from HPMCAS-rich phases. It was noted that the model drug, paracetamol, had more favorable partitioning into the PVP-rich phase, which is likely to be a result of greater hydrogen bonding between PVP and paracetamol. This led to higher drug contents in the PVP-rich phases than the HPMCAS-rich phases. By alternating the proportions of the PVP and HPMCAS, the drug release rate can be modulated.

18. Effects of the rate of releases from Sam Rayburn Reservoir on the Aeration Capacity of the Angelina River, eastern Texas

Rawson, Jack; Goss, Richard L.; Rathbun, Ira G.

1980-01-01

A three-phase study was conducted during July and August 1979 to determine the effects of varying release rates through the power-outlet works at Sam Rayburn Reservoir, eastern Texas, on aeration capacity of a 14-mile reach of the Angelina River below Sam Rayburn Dam. The dominant factors that affected the aeration capacity during the study time were time of travel and the dissolved-oxygen deficit of the releases. Aeration was low throughout the study but increased in response to increases in the dissolved-oxygen deficit and the duration of time that the releases were exposed to the atmosphere (time of travel). The average concentration of dissolved oxygen sustained by release of 8,800 cubic feet per second decreased from 5.0 milligrams per liter at a site near the power outlet to 4.8 milligrams per liter at a site about 14 miles downstream; the time of travel averaged about 8 hours. The average concentration of dissolved oxygen in flow sustained by releases of 2,200 cubic feet per second increased from 5.2 to 5.5 milligrams per liter; the time of travel averaged about 20 hours. (USGS)

19. Estimation of peacock bass (Cichla spp.) mortality rate during catch-release fishing employing different post-capture procedures.

Barroco, L S A; Freitas, C E C; Lima, Á C

2017-08-17

The effect of catch-and-release fishing on the survival of peacock bass (Cichla spp.) was evaluated by comparing two types of artificial bait (jig and shallow-diver plugs) and two types of post-catch confinement. Two experiments were conducted during the periods January-February and October-November 2012 in the Unini River, a right-bank tributary of the Negro River. In total, 191 peacock bass were captured. Both groups of fish were subjected to experimental confinement (collective and individual) for three days. Additionally, 11 fish were tagged with radio transmitters for telemetry monitoring. Mortality rate was estimated as the percentage of dead individuals for each type of bait and confinement. For peacock bass caught with jig baits, mortality was zero. The corresponding figure for shallow-diver bait was 1.66% for fish in collective containment, 18.18% for fish monitored by telemetry and 0% for individuals confined individually. Our results show low post-release mortality rates for peacock bass. Furthermore, neither the type of confinement nor the type of bait had a statistically significant influence on mortality rates. While future studies could include other factors in the analysis, our results show that catch-and-release fishing results in low mortality rates.

20. Anthocyanin Incorporated Dental Copolymer: Bacterial Growth Inhibition, Mechanical Properties, and Compound Release Rates and Stability by 1H NMR

Halyna Hrynash

2014-01-01

Full Text Available Objective. To evaluate bacterial growth inhibition, mechanical properties, and compound release rate and stability of copolymers incorporated with anthocyanin (ACY; Vaccinium macrocarpon. Methods. Resin samples were prepared (Bis-GMA/TEGDMA at 70/30 mol% and incorporated with 2 w/w% of either ACY or chlorhexidine (CHX, except for the control group. Samples were individually immersed in a bacterial culture (Streptococcus mutans for 24 h. Cell viability (n=3 was assessed by counting the number of colony forming units on replica agar plates. Flexural strength (FS and elastic modulus (E were tested on a universal testing machine (n=8. Compound release and chemical stability were evaluated by UV spectrophotometry and 1H NMR (n=3. Data were analyzed by one-way ANOVA and Tukey’s test (α = 0.05. Results. Both compounds inhibited S. mutans growth, with CHX being most effective (P<0.05. Control resin had the lowest FS and E values, followed by ACY and CHX, with statistical difference between control and CHX groups for both mechanical properties (P<0.05. The 24 h compound release rates were ACY: 1.33 μg/mL and CHX: 1.92 μg/mL. 1H NMR spectra suggests that both compounds remained stable after being released in water. Conclusion. The present findings indicate that anthocyanins might be used as a natural antibacterial agent in resin based materials.

1. A theoretical approach to evaluate the release rate of acetaminophen from erosive wax matrix dosage forms.

Agata, Yasuyoshi; Iwao, Yasunori; Shiino, Kai; Miyagishima, Atsuo; Itai, Shigeru

2011-07-29

To predict drug dissolution and understand the mechanisms of drug release from wax matrix dosage forms containing glyceryl monostearate (GM; a wax base), aminoalkyl methacrylate copolymer E (AMCE; a pH-dependent functional polymer), and acetaminophen (APAP; a model drug), we tried to derive a novel mathematical model with respect to erosion and diffusion theory. Our model exhibited good agreement with the whole set of experimentally obtained values pertaining to APAP release at pH 4.0 and pH 6.5. In addition, this model revealed that the eroding speed of wax matrices was strongly influenced by the loading content of AMCE, but not that of APAP, and that the diffusion coefficient increased as APAP loading decreased and AMCE loading increased, thus directly defining the physicochemical properties of erosion and diffusion. Therefore, this model might prove a useful equation for the precise prediction of dissolution and for understanding the mechanisms of drug release from wax matrix dosage forms. Copyright © 2011 Elsevier B.V. All rights reserved.

2. 77 FR 15969 - Waybill Data Released in Three-Benchmark Rail Rate Proceedings

2012-03-19

... compares the R/VC ratios (i.e., percentage markups over variable cost) of particular current movements... compare current rates against older rates or current costs against historical costs, but rather R/VC... its simplified rail rate guidelines, creating a Simplified Stand-Alone Cost approach for...

3. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance.

von Lewinski, Mareike; Biau, Sophie; Erber, Regina; Ille, Natascha; Aurich, Jörg; Faure, Jean-Michel; Möstl, Erich; Aurich, Christine

2013-08-01

Although some information exists on the stress response of horses in equestrian sports, the horse-rider team is much less well understood. In this study, salivary cortisol concentrations, heart rate (HR) and heart rate variability (HRV), SDRR (standard deviation of beat-to-beat interval) and RMSSD (root mean square of successive beat-to-beat intervals) were analysed in horses and their riders (n=6 each) at a public performance and an identical rehearsal that was not open to the public. Cortisol concentrations increased in both horses and riders (Phorses and riders increased during the rehearsal and the public performance (Priders than in their horses during the public performance (from 91 ± 10 to 150 ± 15 beats/min) compared to the rehearsal (from 94 ± 10 to 118 ± 12 beats/min). The SDRR decreased significantly during the equestrian tasks in riders (Phorses. The RMSSD decreased in horses and riders (Priders was more pronounced (Priders than it did in their horses.

4. Preparation of Sinomenine Hydrochloride Sustained Release Tablet and determination of the release rate%盐酸青藤碱缓释片的制备及其释放度测定

洪怡; 刘亚杰; 胡建峰

2012-01-01

Objective To prepare the Sinomenine Hydrochloride Sustained Release Tablet. Methods The prescription was selected by orthogonal design and the investigation index was the effect of EC, MCC and lactose to the release rate. The release rate and the release behavior were studied. Results The release rate of sustained release tablet fitted the first release eqution and the release rate for 12 h was more than 75%. Conclusion The prescription is reasonable, the technology is simple and the release effect is good.%目的 制备盐酸青藤碱缓释片.方法 采用正交设计法,考察乙基纤维素、微晶纤维素、乳糖对缓释片溶出度的影响,进行处方筛选,对最佳处方进行溶出度测定及释放行为的拟合.结果 缓释片的释放行为符合一级释放方程,12 h释放度大于75%.结论 该缓释片处方合理,工艺简单,缓释效果好.

5. Steady State Flammable Gas Release Rate Calculation and Lower Flammability Level Evaluation for Hanford Tank Waste

HU, T.A.

2000-04-27

This work is to assess the steady-state flammability level at normal and off-normal ventilation conditions in the tank dome space for 177 double-shell and single-shell tanks at Hanford. Hydrogen generation rate was calculated for 177 tanks using rate equation model developed recently.

6. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION & LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

HU, T.A.

2005-10-27

Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.

7. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION AND LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

HU TA

2009-10-26

Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.

8. Measuring water-borne cortisol in Poecilia latipinna:is the process stressful, can stress be minimized and is cortisol correlated with sex steroid release rates?

Gabor, C R; Contreras, A

2012-09-01

The stress of water-borne hormone collection process was examined in sailfin mollies Poecilia latipinna. Baseline release rates of the stress hormone cortisol were measured and minimum confinement time for water sampling was evaluated for a standard 60 min v. a 30 min protocol. A 30 min hormone collection period reflects release rates over 60 min. Potential stress response to confinement in the beaker for the water-borne collection process was tested over 4 days. There was no evidence of stress due to the collection methods, as cortisol release rates did not differ significantly across four sequential days of handling for P. latipinna. Males and females did not differ significantly in baseline cortisol release rates. Baseline cortisol release rates from fish immediately after being collected in the field were also not significantly different than those in the 4 day confinement experiment. After exposure to a novel environment, however, P. latipinna mounted a stress response. Stress may also affect sex steroids and behaviour but cortisol release rates were not significantly correlated with sex steroids [11-ketotestosterone (KT), testosterone, or oestradiol], or mating attempts. The correlation between water-borne release rates and plasma steroid levels was validated for both cortisol and KT. Finally, normalizing cortisol release rates using standard length in lieu of mass is viable and accurate. Water-borne hormone assays are a valuable tool for investigating questions concerning the role of hormones in mediating stress responses and reproductive behaviours in P. latipinna and other livebearing fishes.

9. Evaluation of Plantago major L. seed mucilage as a rate controlling matrix for sustained release of propranolol hydrochloride.

Saeedi, Majid; Morteza-Semnani, Katayoun; Sagheb-Doust, Mehdi

2013-03-01

Polysaccharide mucilage derived from the seeds of Plantago major L. (family Plantaginaceae) was investigated for use in matrix formulations containing propranolol hydrochloride. HPMC K4M and tragacanth were used as standards for comparison. The hardness, tensile strength, and friability of tablets increased as the concentration of mucilage increased, indicating good compactibility of mucilage powders. The rate of release of propranolol hydrochloride from P. major mucilage matrices was mainly controlled by the drug/mucilage ratio. Formulations containing P. major mucilage were found to exhibit a release rate comparable to HPMC containing matrices at a lower drug/polymer ratio (drug/HPMC 2:1). These results demonstrated that P. major mucilage is a better release retardant compared to tragacanth at an equivalent content. The results of kinetic analysis showed that in F3 (containing 1:2 drug/mucilage) the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets. The DSC and FT-IR studies showed that no formation of complex between the drug and mucilage or changes in crystallinity of the drug had occurred.

10. Evidence That the Pi Release Event Is the Rate-Limiting Step in the Nitrogenase Catalytic Cycle.

Yang, Zhi-Yong; Ledbetter, Rhesa; Shaw, Sudipta; Pence, Natasha; Tokmina-Lukaszewska, Monika; Eilers, Brian; Guo, Qingjuan; Pokhrel, Nilisha; Cash, Valerie L; Dean, Dennis R; Antony, Edwin; Bothner, Brian; Peters, John W; Seefeldt, Lance C

2016-07-05

Nitrogenase reduction of dinitrogen (N2) to ammonia (NH3) involves a sequence of events that occur upon the transient association of the reduced Fe protein containing two ATP molecules with the MoFe protein that includes electron transfer, ATP hydrolysis, Pi release, and dissociation of the oxidized, ADP-containing Fe protein from the reduced MoFe protein. Numerous kinetic studies using the nonphysiological electron donor dithionite have suggested that the rate-limiting step in this reaction cycle is the dissociation of the Fe protein from the MoFe protein. Here, we have established the rate constants for each of the key steps in the catalytic cycle using the physiological reductant flavodoxin protein in its hydroquinone state. The findings indicate that with this reductant, the rate-limiting step in the reaction cycle is not protein-protein dissociation or reduction of the oxidized Fe protein, but rather events associated with the Pi release step. Further, it is demonstrated that (i) Fe protein transfers only one electron to MoFe protein in each Fe protein cycle coupled with hydrolysis of two ATP molecules, (ii) the oxidized Fe protein is not reduced when bound to MoFe protein, and (iii) the Fe protein interacts with flavodoxin using the same binding interface that is used with the MoFe protein. These findings allow a revision of the rate-limiting step in the nitrogenase Fe protein cycle.

11. Removal rate and releases of polybrominated diphenyl ethers in two wastewater treatment plants, Korea

Lee, Hyo Jin; Kim, Gi Beum

2017-06-01

Wastewater treatment plants (WWTPs) play an important role in minimizing the release of many pollutants into the environment. Nineteen congeners in two WWTPs in Korea were determined to investigate the occurrence and fate of polybrominated diphenyl ethers (PBDEs) during wastewater treatment processes. The concentration of total PBDEs was 69.6 and 183 ng/L in influent, which declined to 1.59 and 2.34 ng/L in the final effluent, respectively (Tongyeong and Jinhae WWTPs). PBDEs were found to exist mostly in the particulate phase of wastewater, which rendered sedimentation efficient for the removal of PBDEs. BDE-209 was the predominant congener in the influent and sludge. Most of the PBDEs entering the WWTPs presumably ended up in the sludge, with WWTP in Korea.

12. STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION & LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE [SEC 1 & 2

HU, T.A.

2003-09-30

Flammable gases such as hydrogen, ammonia, and methane are observed in the tank dome space of the Hanford Site high-level waste tanks. This report assesses the steady-state flammability level under normal and off-normal ventilation conditions in the tank dome space for 177 double-shell tanks and single-shell tanks at the Hanford Site. The steady-state flammability level was estimated from the gas concentration of the mixture in the dome space using estimated gas release rates, Le Chatelier's rule and lower flammability limits of fuels in an air mixture. A time-dependent equation of gas concentration, which is a function of the gas release and ventilation rates in the dome space, has been developed for both soluble and insoluble gases. With this dynamic model, the time required to reach the specified flammability level at a given ventilation condition can be calculated. In the evaluation, hydrogen generation rates can be calculated for a given tank waste composition and its physical condition (e.g., waste density, waste volume, temperature, etc.) using the empirical rate equation model provided in Empirical Rate Equation Model and Rate Calculations of Hydrogen Generation for Hanford Tank Waste, HNF-3851. The release rate of other insoluble gases and the mass transport properties of the soluble gas can be derived from the observed steady-state gas concentration under normal ventilation conditions. The off-normal ventilation rate is assumed to be natural barometric breathing only. A large body of data is required to do both the hydrogen generation rate calculation and the flammability level evaluation. For tank waste that does not have sample-based data, a statistical-based value from probability distribution regression was used based on data from tanks belonging to a similar waste group. This report (Revision 3) updates the input data of hydrogen generation rates calculation for 177 tanks using the waste composition information in the Best-Basis Inventory Detail

13. Reaction rate estimation of controlled-release antifouling paint binders: Rosin-based systems

Meseguer Yebra, Diego; Kiil, Søren; Dam-Johansen, Kim

2005-01-01

at product optimisation and innovation (e.g. incorporation of natural active agents). This study seeks to attain scientifically founded knowledge of the reaction mechanisms and the rate of reaction with sea water of a Zn-carboxylate of a synthetic rosin compound. The kinetic expression attained can be used...... have shown that mathematical coating models based on a fundamental knowledge of the underlying mechanisms of A/F paints is a promising tool for accelerated product testing at different operational conditions of a sailing ship or a paint rotor. Such models can also be used for generation of ideas aiming...... rather than pointing at a certain diffusion control in the reaction rate experiments. The reverse reaction is found not to affect the hydrolysis rate within the pores, of antifouling paints significantly. It is concluded, from the reaction mechanism proposed, that the observed partial exchange of Zn2...

14. Metal release rate from AISI 316L stainless steel and pure Fe, Cr and Ni into a synthetic biological medium--a comparison.

Herting, G; Wallinder, I Odnevall; Leygraf, C

2008-09-01

Metal release rates from stainless steel grade 316L were investigated in artificial lysosomal fluid (ALF), simulating a human inflammatory cell response. The main focus was placed on release rates of main alloying elements using graphite furnace atomic absorption spectroscopy, and changes in surface oxide composition by means of X-ray photoelectron spectroscopy. To emphasise that alloys and pure metals possess totally different intrinsic properties, comparative studies were performed on the pure alloying constituents: iron, nickel and chromium. Significant differences in release rates were observed due to the presence of a passive surface film on stainless steel. Iron and nickel were released at rates more than 300 times lower from the 316L alloy compared with the pure metals whereas the release rate of chromium was similar. Iron was preferentially released compared with nickel and chromium. Immersion in ALF resulted in the gradual enrichment of chromium in the surface film, a small increase of nickel, and the reduction of oxidized iron with decreasing release rates of alloy constituents as a result. As expected, released metals from stainless steel grade 316L were neither in proportion to the bulk alloy composition nor to the surface film composition.

15. Star Formation Rate Indicators in Wide-Field Infrared Survey Preliminary Release

Fei Shi; Xu Kong; James Wicker; Yang Chen; Zi-Qiang Gong; Dong-Xin Fan

2012-06-01

With the goal of investigating the degree at which the MIR luminosity in the Wide-field Infrared Survey Explorer (WISE) traces the SFR, we analyse 3.4, 4.6, 12 and 22 m data in a sample of ∼ 140,000 star-forming galaxies or star-forming regions covering a wide range in metallicity 7.66 < 12 + \\log (O/H) < 9.46, with redshift < 0.4. These star-forming galaxies or star-forming regions are selected by matching the WISE Preliminary Release Catalog with the star-forming galaxy Catalog in SDSS DR8 provided by JHU/MPA. We study the relationship between the luminosity at 3.4, 4.6, 12 and 22 m from WISE and H luminosity in SDSS DR8. From these comparisons, we derive reference SFR indicators for use in our analysis. Linear correlations between SFR and the 3.4, 4.6, 12 and 22 m luminosity are found, and calibrations of SFRs based on L(3.4), L(4.6), L(12) and L(22) are proposed. The calibrations hold for galaxies with verified spectral observations. The dispersion in the relation between 3.4, 4.6, 12 and 22 m luminosity and SFR relates to the galaxy’s properties, such as 4000 Å break and galaxy color.

16. CDC Releases Report on 30-Year Low in Youth Homicide Rates

... is one too many. Comprehensive approaches that include evidence-based prevention strategies are essential to eliminate homicide as ... to 24 years, and 28.8 for non-Hispanic black youth. The annual rate ... school-based programs that build students’ communications skills to solve ...

17. Growth rates and post-release survival of captive neonate timber rattlesnakes Crotalus horridus

Richard N. Conner; D. Craig Rudolph; Daniel Saenz; Richard R. Schaefer; Shirley J. Burgdorf

2003-01-01

The need for conservation and management of rare species is becoming increasingly important as wildlife species and their habitat continue to decline. Translocation of wild captured adults to augment and reintroduce populations has been successfully used for some endangered avian species (see Carrie et al. 1999; Rudolph et al. 1992). In general, success rates for...

18. Sill intrusion driven fluid flow and vent formation in volcanic basins: Modeling rates of volatile release and paleoclimate effects

Iyer, Karthik; Schmid, Daniel

2016-04-01

Evidence of mass extinction events in conjunction with climate change occur throughout the geological record and may be accompanied by pronounced negative carbon isotope excursions. The processes that trigger such globally destructive changes are still under considerable debate. These include mechanisms such as poisoning from trace metals released during large volcanic eruptions (Vogt, 1972), CO2 released from lava degassing during the formation of Large Igneous Provinces (LIPs) (Courtillot and Renne, 2003) and CH4 release during the destabilization of sub-seafloor methane (Dickens et al., 1995), to name a few. Thermogenic methane derived from contact metamorphism associated with magma emplacement and cooling in sedimentary basins has been recently gaining considerable attention as a potential mechanism that may have triggered global climate events in the past (e.g. Svensen and Jamtveit, 2010). The discovery of hydrothermal vent complexes that are spatially associated with such basins also supports the discharge of greenhouse gases into the atmosphere (e.g. Jamtveit et al., 2004; Planke et al., 2005; Svensen et al., 2006). A previous study that investigated this process using a fluid flow model (Iyer et al., 2013) suggested that although hydrothermal plume formation resulting from sill emplacement may indeed release large quantities of methane at the surface, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative δ13C excursions observed in the fossil record over short time scales observed in the fossil record. Here, we reinvestigate the rates of gas release during sill emplacement in a case study from the Harstad Basin off-shore Norway with a special emphasis on vent formation. The presented study is based on a seismic line that crosses multiple sill structures emplaced around 55 Ma within the Lower Cretaceous sediments. A single well-defined vent complex is interpreted above the termination of the

19. Statistical correlation of the soil incubation and the accelerated laboratory extraction methods to estimate nitrogen release rates of slow- and controlled-release fertilizers.

Medina, L Carolina; Sartain, Jerry; Obreza, Thomas; Hall, William L; Thiex, Nancy J

2014-01-01

Several technologies have been proposed to characterize the nutrient release patterns of enhanced-efficiency fertilizers (EEFs) during the last few decades. These technologies have been developed mainly by manufacturers and are product-specific based on the regulation and analysis of each EEF product. Despite previous efforts to characterize nutrient release of slow-release fertilizer (SRF) and controlled-release fertilizer (CRF) materials, no official method exists to assess their nutrient release patterns. However, the increased production and distribution of EEFs in specialty and nonspecialty markets requires an appropriate method to verify nutrient claims and material performance. Nonlinear regression was used to establish a correlation between the data generated from a 180-day soil incubation-column leaching procedure and 74 h accelerated lab extraction method, and to develop a model that can predict the 180-day nitrogen (N) release curve for a specific SRF and CRF product based on the data from the accelerated laboratory extraction method. Based on the R2 > 0.90 obtained for most materials, results indicated that the data generated from the 74 h accelerated lab extraction method could be used to predict N release from the selected materials during 180 days, including those fertilizers that require biological activity for N release.

20. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

2008-01-01

Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

1. On the Impact of the Fuel Dissolution Rate Upon Near-Field Releases From Nuclear Waste Disposal

A Pereira

2016-09-01

Full Text Available Calculations of the impact of the dissolution of spent nuclear fuel on the release from a damaged canister in a KBS-3 repository are presented. The dissolution of the fuel matrix is a complex process and the dissolution rate is known to be one of the most important parameters in performance assessment models of the near-field of a geological repository. A variability study has been made to estimate the uncertainties associated with the process of fuel dissolution. The model considered in this work is a 3D model of a KBS-3 copper canister. The nuclide used in the calculations is Cs-135. Our results confirm that the fuel degradation rate is an important parameter, however there are considerable uncertainties associated with the data and the conceptual models. Consequently, in the interests of safety one should reduce, as far as possible, the uncertainties coupled to fuel degradation.

2. Impact of Eudragit EPO and hydroxypropyl methylcellulose on drug release rate, supersaturation, precipitation outcome and redissolution rate of indomethacin amorphous solid dispersions.

Xie, Tian; Gao, Wei; Taylor, Lynne S

2017-10-05

The purpose of this work was to evaluate the impact of polymer(s) on the dissolution rate, supersaturation and precipitation of indomethacin amorphous solid dispersions (ASD), and to understand the link between precipitate characteristics and redissolution kinetics. The crystalline and amorphous solubilities of indomethacin were determined in the absence and presence of hydroxypropylmethyl cellulose (HPMC) and/or Eudragit (®) EPO to establish relevant phase boundaries. At acidic pH, HPMC could maintain supersaturation of the drug by effectively inhibiting solution crystallization while EPO increased both the crystalline and amorphous solubility of the drug, but did not inhibit crystallization. The HPMC dispersion dissolved relatively slowly without undergoing crystallization while the supersaturation generated by rapid dissolution of the EPO ASD was short-lived due to crystallization. The crystals thus generated underwent rapid redissolution upon pH increase, dissolving faster than the reference crystalline material, and at a comparable rate to the amorphous HPMC dispersion. A ternary dispersion containing both EPO and HPMC dissolved rapidly, generating an apparent drug concentration that exceeded the amorphous solubility of indomethacin, leading to the formation of a new nanosized droplet phase. These nanodroplets dissolved virtually immediately when the pH was increased. In conclusion, the concentration-time profiles achieved from indomethacin ASD dissolution are a complex interplay of drug release rate, precipitation kinetics and outcome, and precipitate redissolution rate, whereby each of these processes is highly dependent on the polymer(s) employed in the formulation. Copyright © 2017 Elsevier B.V. All rights reserved.

3. 川芎嗪自乳化缓释固体分散体释放度测定方法研究%Study on Release Rate of TMP Self-emulsifying Release Solid Dispersion

陈道阳; 陈晓丹; 王利胜

2012-01-01

Objective: To establish release rate determination methods of TMP self-emulsifying release solid dispersion. Methods: HPLC was applied to determine the content of TMP, and different effects on release rate of TMP self-emulsifying release solid dispersion were studied in vitro. Results: The release medium was degassed pure water, the rotation speed was 50r · min-1. Conclusion: A good method to determine release rate of TMP self-emulsifying release solid dispersion was established, providing a basis to evaluate and control the quality of drugs.%目的:建立川芎嗪自乳化缓释固体分散体释放度测定方法.方法:采用HPLC法测定川芎嗪自乳化缓释固体分散体中TMP的含量,考察相关因素对其体外释药的影响.结果:以转篮法为溶出度测定方法,释放介质为脱气纯水,转速为50r/min.结论:建立了良好的川芎嗪自乳化缓释固体分散体释放度测定方法,为评价和控制该药的质量提供依据.

Shikha Jain

2016-01-01

Full Text Available OBJECTIVES: The objective of the study is to evaluate the efficacy of gonadotropin-releasing hormone (GnRH antagonist in improving clinical pregnancy rate in gonadotropin-stimulated intrauterine insemination (IUI cycles in patients of unexplained infertility. STUDY DESIGN: This was a prospective, randomized case-controlled study. SETTINGS: The study was conducted in the infertility clinic of a tertiary care center. MATERIALS AND METHODS: Four hundred twenty-seven women undergoing IUI following controlled ovarian stimulation with gonadotropins (recombinant follicle-stimulating hormone [r-FSH] 75 IU/day were randomly divided into two groups. Women in Group I received GnRH antagonist (Cetrorelix 0.25 mg/day in a multiple dose flexible protocol. Women in Group II received r-FSH alone. Ovulatory trigger was given with human chorionic gonadotropin 5000 IU when dominant follicle was ≥18 mm. IUI was performed within 44-48 h. Both groups received similar luteal phase support. Primary outcome measure was clinical pregnancy rate. The trial was powered to detect an absolute increase in clinical pregnancy rate by 13% from an assumed 20% clinical pregnancy rate in the control group, with an alpha error level of 0.05 and a beta error level of 0.20. RESULTS: Clinical pregnancy rate in Groups I and II was 27.6% (n = 56 and 26.5% (n = 54, respectively (P=0.800. Ongoing pregnancy and multiple pregnancy rates were likewise similar between the groups. CONCLUSIONS: Addition of GnRH antagonist to gonadotropin-stimulated IUI cycles results in no significant difference in clinical pregnancy rate.

5. The effect of inorganic cations Ca2+ and Al3+ on the release rate of propranolol hydrochloride from sodium carboxymethylcellulose matrices

2009-08-01

Full Text Available Background and purpose of the study: Several methods are available for control release of propranolol hydrochloride (PLH. The aim of the present study was to develop a novel technique to sustain PLH release from matrices. Materials and methods: Matrices of PLH containing sodium carboxymethylcellulose (Na CMC and various amounts of the inorganic cations Ca2+ and Al3+ were prepared. Dissolution of the matrices was carried out using the USP apparatus I. Analysis of release data was performed by some model independent and dependent approaches.    Results: The release of PLH was affected by incorporation of different amounts (milliequivalents, meq of Ca2+ and Al3+. When the Ca2+amount increased from 0- 0.375 meq, the fraction of PLH which released within 480 min was augmented from 0.74 to 1 apparently via disintegrating effect of the cation. Al3+in the range 0- 0.125 meq, decreased the fractional release from 0.74 to 0.37 presumably by in situ cross- linking with polymer. Al3+ between 0.125 and 0.5 meq enhanced the release from 0.37 to 1 possibly due to the disintegrating effect. Among model independent metrics, the mean release time (MRT failed to represent the effect of the cations on the release but the release efficiency (RE as well as a suggested mean release rate (MRR correlated well with the experimental release rate. Due to the complexity of the release, the only suitable kinetic model was the Weibull distribution. The minimum and maximum Weibull release rate constants for matrices containing Al3+ were 0.0007-0.017 1/min. The corresponding values for the matrices with Ca2+ were 0.0029-0.0082 1/min. Conclusion: Through careful choice of the amount of Al3+in NaCMC matrices the release of PLH can be controlled at a desired rate. The best model independent approach is MRR and the most accurate model dependent method is Weibull distribution to describe the release data.

6. Deuterium isotope effects on toluene metabolism. Product release as a rate-limiting step in cytochrome P-450 catalysis

Ling, K.H.; Hanzlik, R.P.

1989-04-28

Liver microsomes from phenobarbital-induced rats oxidize toluene to a mixture of benzyl alcohol plus o-, m- and p-cresol (ca. 69:31). Stepwise deuteration of the methyl group causes stepwise decreases in the yield of benzyl alcohol relative to cresols (ca. 24:76 for toluene-d3). For benzyl alcohol formation from toluene-d3 DV = 1.92 and D(V/K) = 3.53. Surprisingly, however, stepwise deuteration induces stepwise increases in total oxidation, giving rise to an inverse isotope effect overall (DV = 0.67 for toluene-d3). Throughout the series (i.e. d0, d1, d2, d3) the ratios of cresol isomers remain constant. These results are interpreted in terms of product release for benzyl alcohol being slower than release of cresols (or their epoxide precursors), and slow enough to be partially rate-limiting in turnover. Thus metabolic switching to cresol formation causes a net acceleration of turnover.

7. Angiotensin II and renal prostaglandin release in the dog. Interactions in controlling renal blood flow and glomerular filtration rate.

Bugge, J F; Stokke, E S

1994-04-01

The relationship between angiotensin II and renal prostaglandins, and their interactions in controlling renal blood flow (RBF) and glomerular filtration rate (GFR) were investigated in 18 anaesthetized dogs with acutely denervated kidneys. Intrarenal angiotensin II infusion increased renal PGE2 release (veno-arterial concentration difference times renal plasma flow) from 1.7 +/- 0.9 to 9.1 +/- 0.4 and 6-keto-PGF1 alpha release from 0.1 +/- 0.1 to 5.3 +/- 2.1 pmol min-1. An angiotensin II induced reduction in RBF of 20% did not measurably change GFR whereas a 30% reduction reduced GFR by 18 +/- 8%. Blockade of prostaglandin synthesis approximately doubled the vasoconstrictory action of angiotensin II, and all reductions in RBF were accompanied by parallel reductions in GFR. When prostaglandin release was stimulated by infusion of arachidonic acid (46.8 +/- 13.3 and 15.9 +/- 5.4 pmol min-1 for PGE2, and 6-keto-PGF1 alpha, respectively), angiotensin II did not change prostaglandin release, but had similar effects on the relationship between RBF and GFR as during control. In an ureteral occlusion model with stopped glomerular filtration measurements of ureteral pressure and intrarenal venous pressure permitted calculations of afferent and efferent vascular resistances. Until RBF was reduced by 25-30% angiotensin II increased both afferent and efferent resistances almost equally, keeping the ureteral pressure constant. At greater reductions in RBF, afferent resistance increased more than the efferent leading to reductions in ureteral pressure. This pattern was not changed by blockade of prostaglandin synthesis indicating no influence of prostaglandins on the distribution of afferent and efferent vascular resistances during angiotensin II infusion. In this ureteral occlusion model glomerular effects of angiotensin II will not be detected, and it might well be that the shift from an effect predominantly on RBF to a combined effect on both RBF and GFR induced by inhibition

8. Energy Release Rate in hydraulic fracture: can we neglect an impact of the hydraulically induced shear stress?

Wrobel, Michal; Piccolroaz, Andrea

2016-01-01

A novel hydraulic fracture (HF) formulation is introduced which accounts for the hydraulically induced shear stress at the crack faces. It utilizes a general form of the elasticity operator alongside a revised fracture propagation condition based on the critical value of the energy release rate. It is shown that the revised formulation describes the underlying physics of HF in a more accurate way and is in agreement with the asymptotic behaviour of the linear elastic fracture mechanics. A number of numerical simulations by means of the universal HF algorithm previously developed in Wrobel & Mishuris (2015) are performed in order to: i) compare the modified HF formulation with its classic counterpart and ii) investigate the peculiarities of the former. Computational advantages of the revised HF model are demonstrated. Asymptotic estimations of the main solution elements are provided for the cases of small and large toughness. The modified formulation opens new ways to analyse the physical phenomenon of HF ...

9. Releasable activity and maximum permissible leakage rate within a transport cask of Tehran Research Reactor fuel samples

Rezaeian Mahdi

2015-01-01

Full Text Available Containment of a transport cask during both normal and accident conditions is important to the health and safety of the public and of the operators. Based on IAEA regulations, releasable activity and maximum permissible volumetric leakage rate within the cask containing fuel samples of Tehran Research Reactor enclosed in an irradiated capsule are calculated. The contributions to the total activity from the four sources of gas, volatile, fines, and corrosion products are treated separately. These calculations are necessary to identify an appropriate leak test that must be performed on the cask and the results can be utilized as the source term for dose evaluation in the safety assessment of the cask.

10. Effect of ethanol, temperature, and gas flow rate on volatile release from aqueous solutions under dynamic headspace dilution conditions.

Tsachaki, Maroussa; Gady, Anne-Laure; Kalopesas, Michalis; Linforth, Robert S T; Athès, Violaine; Marin, Michele; Taylor, Andrew J

2008-07-09

On the basis of a mechanistic model, the overall and liquid mass transfer coefficients of aroma compounds were estimated during aroma release when an inert gas diluted the static headspace over simple ethanol/water solutions (ethanol concentration = 120 mL x L(-1)). Studied for a range of 17 compounds, they were both increased in the ethanol/water solution compared to the water solution, showing a better mass transfer due to the presence of ethanol, additively to partition coefficient variation. Thermal imaging results showed differences in convection of the two systems (water and ethanol/water) arguing for ethanol convection enhancement inside the liquid. The effect of ethanol in the solution on mass transfer coefficients at different temperatures was minor. On the contrary, at different headspace dilution rates, the effect of ethanol in the solution helped to maintain the volatile headspace concentration close to equilibrium concentration, when the headspace was replenished 1-3 times per minute.

11. Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses.

Schmidt, Alice; Aurich, Jörg; Möstl, Erich; Müller, Jürgen; Aurich, Christine

2010-09-01

Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions (n=9) and mares (n=7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations (pCortisol release varied between training units and occasionally was more pronounced in mares than in stallions (p<0.05). The RR interval decreased slightly in response to lunging before mounting of the rider. A pronounced decrease occurred when the rider was mounting, but before the horse showed physical activity (p<0.001). The HRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider (p<0.001). Thereafter RR interval and HRV variables increased again. In contrast, SD2 increased with the beginning of lunging (p<0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions.

12. Effects of pH, Temperature, Dissolved Oxygen, and Flow Rate on Phosphorus Release Processes at the Sediment and Water Interface in Storm Sewer

Haiyan Li

2013-01-01

Full Text Available The effects of pH, temperature, dissolved oxygen (DO, and flow rate on the phosphorus (P release processes at the sediment and water interface in rainwater pipes were investigated. The sampling was conducted in a residential storm sewer of North Li Shi Road in Xi Cheng District of Beijing on August 3, 2011. The release rate of P increased with the increase of pH from 8 to 10. High temperature is favorable for the release of P. The concentration of total phosphorus (TP in the overlying water increased as the concentration of DO decreased. With the increase of flow rate from 0.7 m s−1 to 1.1 m s−1, the concentration of TP in the overlying water increased and then tends to be stable. Among all the factors examined in the present study, the flow rate is the primary influence factor on P release. The cumulative amount of P release increased with the process of pipeline runoff in the rainfall events with high intensities and shorter durations. Feasible measures such as best management practices and low-impact development can be conducted to control the P release on urban sediments by slowing down the flow rate.

13. A GTPase chimera illustrates an uncoupled nucleotide affinity and release rate, Providing insight into the activation mechanism

Guilfoyle, Amy P.; Deshpande, Chandrika N.; Font Sadurni, Josep

2014-01-01

for GDP release, or, alternatively, the movement is a consequence of release. To gain additional insight into the sequence of events leading to GDP release, we have created a chimeric protein comprised of Escherichia coli NFeoB and the G5 loop from the human Giα1 protein. The protein chimera retains...

14. In vitro fertility rate of 129 strain is improved by buserelin (gonadotropin-releasing hormone) administration prior to superovulation.

Vasudevan, K; Sztein, J M

2012-10-01

The 129 mice are well recognized for their low fertility and it is speculated that this lack of fertility may be due to the oocyte condition. In this study we investigated superovulation regimens for the 129S1/SvImJ mouse strain to improve the oocyte quality and fertility rate of in vitro fertilization (IVF). Female mice were divided into four groups based on hormone and timing of injection. Group 1 received pregnant mare serum gonadotropin (PMSG) and 48 h later human chorionic gonadotropin (hCG); using the same dose, group 2 received hCG 52 h post-PMSG and group 3, 55 h post-PMSG. Group 4 received buserelin (gonadotropin-releasing hormone agonist [GnRH]) followed 24 h later by PMSG and then hCG 55 h post-PMSG. IVF was performed using 129S1/SvImJ oocytes and sperm; C57BL/6J sperm with 129S1/SvImJ oocytes was used as fertility control. The IVF fertility rate was 1% (Groups 1 and 2), 17% (Group 3) and 55% (Group 4) for 129 oocytes fertilized with 129 sperm. For 129 oocytes fertilized with C57BL/6J sperm, the fertility rate was 5% (Group 1), 10% (Group 2), 40% (Group 3) and 59% (Group 4). These results suggest that extending the interval time between PMSG and hCG and giving GnRH in addition to the standard PMSG and hCG treatments can improve IVF fertility rate of 129S1/SvImJ mouse strains significantly.

15. Effects of administration of gonadotropin-releasing hormone at artificial insemination on conception rates in dairy cows.

Shephard, R W; Morton, J M; Norman, S T

2014-01-10

A controlled trial investigating the effect on conception of administration of 250 μg of gonadotropin-releasing hormone (GnRH) at artificial insemination (AI) in dairy cows in seasonal or split calving herds was conducted. Time of detection of estrus, body condition, extent of estrous expression, treatment, breed, age and milk production from the most recent herd test of the current lactation was recorded. Cows were tested for pregnancy with fetal aging between 35 and 135 days after AI. Sixteen herds provided 2344 spring-calved cows and 3007 inseminations. Logistic regression adjusting for clustering at herd level was used to examine the effect of treatment for first (2344) and second (579) inseminations separately. For first AI, treatment significantly improved conception rate in cows with milk protein concentrations of 3.75% or greater and for cows with milk protein concentrations between 3.00% and 3.50% and less than 40 days calved; increased conception rate from 41.2% to 53.4%. Treatment reduced conception rates in cows with milk protein concentrations of 2.75% or less. Treating only cows identified as responding positively to treatment (11% of all study cows) was estimated to increase first service conception rate in herds from 48.1% to 49.4%. There was no significant effect of treatment on conception to second AI, nor any significant interactions. These findings indicate that GnRH at AI should be limited to the sub-group cows most likely to respond. The positive effect of GnRH at AI may be mediated through improved oocyte maturation and/or improved luteal function, rather than by reducing AI-to-ovulation intervals.

16. Ovarian responses and pregnancy rate with previously used intravaginal progesterone releasing devices for fixed-time artificial insemination in sheep.

Vilariño, M; Rubianes, E; Menchaca, A

2013-01-01

The objective was to determine serum progesterone concentrations, ovarian responses, and pregnancy rate in sheep inseminated following a short-term protocol (6 days of treatment) with a previously used controlled internal drug release-G (CIDR-G) device. In experiment 1, 30 ewes were put on a short-term protocol using a CIDR-G of first use (new devices, N = 10), second use (previously used for 6 days, N = 10), or third use (previously used twice for 6 days, N = 10). All ewes were given prostaglandin F(2α) (10 mg dinoprost) and eCG (300 IU) im at device withdrawal. Mean serum progesterone concentrations were greater for ewes treated with new versus reused devices (P synchronization and ovulation, with lower serum progesterone concentrations for reused devices. Three times used CIDR-G yielded a pregnancy rate >70%, which tended to be lower than that obtained with new devices, adding evidence of the detrimental effect of low serum progesterone concentrations on fertility in sheep.

17. Pregnancy rates to timed artificial insemination in dairy cows treated with gonadotropin-releasing hormone or porcine luteinizing hormone.

Colazo, M G; Gordon, M B; Rajamahendran, R; Mapletoft, R J; Ambrose, D J

2009-07-15

We compared the effects of porcine luteinizing hormone (pLH) versus gonadotropin-releasing hormone (GnRH) on ovulatory response and pregnancy rate after timed artificial insemination (TAI) in 605 lactating dairy cows. Cows (mean+/-SEM: 2.4+/-0.08 lactations, 109.0+/-2.5 d in milk, and 2.8+/-0.02 body condition score) at three locations were assigned to receive, in a 2x2 factorial design, either 100 microg GnRH or 25mg pLH im on Day 0, 500 microg cloprostenol (PGF) on Day 7, and GnRH or pLH on Day 9, with TAI 14 to 18h later. Ultrasonographic examinations were performed in a subset of cows on Days 0, 7, 10, and 11 to determine ovulations, presence of corpus luteum, and follicle diameter and in all cows 32 d after TAI for pregnancy determination. In 35 cows, plasma progesterone concentrations were determined 0, 3, 4, 5, 6, 7, and 12 d after ovulation. The proportion of noncyclic cows and cows with ovarian cysts on Day 0 were 12% and 6%, respectively. Ovulatory response to first treatment was 62% versus 44% for pLH and GnRH and 78% versus 50% for noncyclic and cyclic cows (PpLH or GnRH, cyclic status, presence of an ovarian cyst, and preovulatory follicle size did not affect pregnancy rate. Plasma progesterone concentrations after TAI did not differ among treatments. Pregnancy rate to TAI was greater (PpLH group (42%) than in the other three groups (28%, 30%, and 26% for GnRH/PGF/GnRH, pLH/PGF/GnRH, and pLH/PGF/pLH, respectively). Although only 3% of cows given pLH in lieu of GnRH on Day 9 lost their embryo versus 7% in those subjected to a conventional TAI using two GnRH treatments, the difference was not statistically significant. In summary, pLH treatment on Day 0 increased ovulatory response but not pregnancy rate. Cows treated with GnRH/PGF/pLH had the highest pregnancy rate to TAI, but progesterone concentrations after TAI were not increased. In addition, preovulatory follicle diameter did not affect pregnancy rate.

18. Theoretical prediction of energy release rate for interface crack initiation by thermal stress in environmental barrier coatings for ceramics

Kawai, E.; Umeno, Y.

2017-05-01

As weight reduction of turbines for aircraft engines is demanded to improve fuel consumption and curb emission of carbon dioxide, silicon carbide (SiC) fiber reinforced SiC matrix composites (SiC/SiC) are drawing enormous attention as high-pressure turbine materials. For preventing degradation of SiC/SiC, environmental barrier coatings (EBC) for ceramics are deposited on the composites. The purpose of this study is to establish theoretical guidelines for structural design which ensures the mechanical reliability of EBC. We conducted finite element method (FEM) analysis to calculate energy release rates (ERRs) for interface crack initiation due to thermal stress in EBC consisting of Si-based bond coat, Mullite and Ytterbium (Yb)-silicate layers on a SiC/SiC substrate. In the FEM analysis, the thickness of one EBC layer was changed from 25 μm to 200 μm while the thicknesses of the other layers were fixed at 25 μm, 50 μm and 100 μm. We compared ERRs obtained by the FEM analysis and a simple theory for interface crack in a single-layered structure where ERR is estimated as nominal strain energy in the coating layers multiplied by a constant factor (independent of layer thicknesses). We found that, unlike the case of single-layered structures, the multiplication factor is no longer a constant but is determined by the combination of consisting coating layer thicknesses.

19. RESEARCH FOR THE STRAIN ENERGY RELEASE RATE OF COMPLEX CRACKS BY USING POINT-BY-POINT CLOSED EXTRAPOLATION APPROACH

郭茂林; 孟庆元; 王彪

2003-01-01

A new extrapolation approach was proposed to calculate the strain energy release rates of complex cracks. The point-by-point closed method was used to calculate the closed energy, thus the disadvantage of self inconsistency in some published papers can be avoided. The disadvantage is that the closed energy is repeatedly calculated: when closed nodal number along radial direction is more than two, the displacement of nodes behind the crack tip that is multiplied by nodal forces, the closed energy has been calculated and the crack surfaces have been closed, and that closed energy of middle point is calculated repeatedly. A DCB ( double cantilever beam) specimen was calculated and compared with other theoretical results, it is shown that a better coincidence is obtained. In addition the same results are also obtained for compact tension specimen, three point bend specimen and single edge cracked specinen. In comparison with theoretical results, the error can be limited within 1 per cent. This method can be extended to analyze the fracture of composite laminates with various delamination cracks.

20. Comparison of release rates of ibuprofen sustained-release capsules from different manufacturers%不同厂家布洛芬缓释胶囊体外释放度比较

彭秋燕; 许煜静; 许文婷; 李翔宇; 杨金荣

2013-01-01

目的:考察9个不同厂家的布洛芬缓释胶囊的体外释放度并与芬必得缓释胶囊进行对比,为临床合理用药提供参考.方法:按照《中华人民共和国药典》2010年版有关布洛芬缓释胶囊释放度测定的规定,采用转篮法的装置进行体外溶出实验,用高效液相色谱法进行含量测定,计算累积释放百分率,进行释药曲线拟合,比较溶出参数,并通过计算相似因子的方法与芬必得进行比较.结果:9个厂家中仅F厂的产品释放不符合要求,其余厂家产品释放度均符合要求,且与芬必得缓释胶囊相似因子大于50.除F厂家外,其余厂家产品的释药曲线均符合威布尔方程.结论:不同厂家产品存在内在差异,可为临床用药提供参考.%Objective: To investigate the release rates of different ibuprofen sustained-release capsules in vitro by comparing with fen-bid, thus provide a reference for its rational use in clinical. Methods: The release rate tests of ibuprofen sustained-release capsules were performed accordance to China Pharmacopeia (2010 edition, basket-rotating method of drug release rate), and the release amount was determined by HPLC. Release curve was used to fit different equation, and the parameters of m, T50 and Td were caculated and compared with fenbid. f2 factor was calculated to compare their similarity with fenbid. Results: The f2 factors of nine manufacturers' products with fenbid were greater than 50, except for F capsule. And their release curves are fit with Weibull equation. Conclusion: There are differences in dissolution parameters among the ibuprofen sustained-release capsules from different manufacturers.

1. Study on detection method of niacin release rate in lovastatin and niacin ustained-release tablets%洛伐他汀烟酸缓释片中烟酸释放度检测方法研究

蒋艳霞; 秦晶晶; 焦志斌

2013-01-01

目的 建立洛伐他汀烟酸缓释片中烟酸释放度的最佳检测方法.方法 参照ADVICOR中烟酸释放度测定方法,将水做为释放介质,温度(37±0.5)℃,转速为100 r/min,作为本实验中烟酸的释放条件;照中紫外-可见分光光度法(2010版附录Ⅳ A),选用262 nm作为烟酸溶出量紫外检测波长.结果 烟酸的溶出量不受辅料影响;浓度在11.01-27.13 μg/ml范围内回收率大于99.70%;体外24 h内烟酸的稳定性良好;在3.88-23.28 μg/ml浓度范围内,紫外吸光度与溶液浓度呈良好的线性关系;烟酸释放均一性没有显著差异.结论 此方法适合洛伐他汀烟酸缓释片中烟酸释放度的测定.%Objective To establish an optimal detection method of niacin in lovastatin and niacin sustained-release tablets. Methods Referring to the detection method of the release rate of niacin in ADVICOR(R) , niacin release conditions were as follows: water as the release medium,( 37 ±0.5 )℃ ,100 r/min. According to UV-Vis spectrophotometry in Chinese Pharmacopoeia( 2010 version of Appendix ⅣA ) , niacin detection wavelength was set at 262 nm. Results Niacin release rate was not affected by the excipients. Recovery rate was more than 99. 70% at the concentrations of 11.01- 27. 13 μg/ml. Nician stability in vitro was good in 24 h. It showed a good linear relationship between UV absorbance and the solution concentration in the range of 3. 88 - 23. 28 μg/ml. Niacin release homogeneity was not significantly different. Conclusion This method is suitable for detecting the niacin release rate in lovastatin and niacin sustained-release tablets.

2. Arthroscopic lateral retinacular releasing to treat patellofemoral compression syndrome%膝关节镜下松解髌骨外侧支持带治疗髌股压迫综合征

杨丰全; 黄东辉; 陈聪; 杨丰建

2013-01-01

目的 探讨膝关节镜下髌骨外侧支持带松解(ALRR)对髌股压迫综合征(PFCS)的疗效.方法 对81例PFCS患者行膝关节镜下ALRR+清理术.术后积极进行康复训练.采用Lysholm膝关节功能评分评价疗效.结果 81例均获随访,时间14~36个月.术后1个月,患者膝关节疼痛明显减轻或消失.1年后膝关节Lysholm评分:优54例,良16例,可8例,差3例,优良率为86.4%;患者主观满意率为91.4%.结论 膝关节镜下ALRR治疗PFCS创伤小,可同时在关节镜下进行关节清理术;对髌股疼痛伴有髌骨向外侧倾斜的PFCS疗效满意.术后采取积极的康复训练能明显提高疗效.

3. Effect of binders on the release rates of direct molded verapamil tablets using twin-screw extruder in melt granulation.

Tan, David Cheng Thiam; Chin, William Wei Lim; Tan, En Hui; Hong, Shiqi; Gu, Wei; Gokhale, Rajeev

2014-03-10

Conventional manufacturing of pharmaceutical tablets often involves single processes such as blending, granulation, milling and direct compression. A process that minimizes and incorporates all these in a single continuous step is desirable. The concept of omitting milling step followed by direct-molding of tablets utilizing a twin-screw extruder in a melt granulation process using thermoplastic binders was explored. The objective of this study was to investigate the effect of combining hydrophilic binder (HPMC K4M, PEO 1M), and hydrophobic binder (Compritol® ATO 888, Precirol® ATO 5) on the release profiles of direct-molded tablets and direct-compressed tablets from milled extrudates using a quality-by-design approach. It was identified that hydrophilic binder type and process significantly affects (p=0.005) the release profiles of verapamil. Moreover, two-way interaction analysis demonstrated that the combination of process with type of hydrophilic polymer (p=0.028) and the type of hydrophilic polymer with polymer ratio (p=0.033) significantly affected the release profiles. The formulation release kinetics correlated to Higuchi release model and the mechanism correlated to a non-Fickian release mechanism. The results of the present study indicated that direct-molded tablets with different release profiles can be manufactured without milling process and through a continuous melt granulation using twin-screw extruder with appropriate thermoplastic binder ratio.

4. The release of dipicolinic acid--the rate-limiting step of Bacillus endospore inactivation during the high pressure thermal sterilization process.

Reineke, Kai; Schlumbach, Karl; Baier, Daniel; Mathys, Alexander; Knorr, Dietrich

2013-03-01

High pressure combined with elevated temperatures can produce low acid, commercially sterile and shelf-stable foods. Depending on the temperature and pressure levels applied, bacterial endospores pass through different pathways, which can lead to a pressure-induced germination or inactivation. Regardless of the pathway, Bacillus endospores first release pyridine-2,6-dicarboxylic acid (DPA), which contributes to the low amount of free water in the spore core and is consequently responsible for the spore's high resistance against wet and dry heat. This is therefore the rate-limiting step in the high pressure sterilization process. To evaluate the impact of a broad pressure, temperature and time domain on the DPA release, Bacillus subtilis spores were pressure treated between 0.1 and 900 MPa at between 30 and 80 °C under isothermal isobaric conditions during dwell time. DPA quantification was assessed using HPLC, and samples were taken both immediately and 2 h after the pressure treatment. To obtain a release kinetic for some pressure-temperature conditions, samples were collected between 1s and 60 min after decompression. A multiresponse kinetic model was then used to derive a model covering all kinetic data. The isorate lines modeled for the DPA release in the chosen pressure-temperature landscape enabled the determination of three distinct zones. (I) For pressures 50 °C, a 90% DPA release was achievable in less than 5 min and no difference in the amount of DPA was found immediately 2 h after pressurization. This may indicate irreversible damage to the inner spore membrane or membrane proteins. (II) Above 600 MPa the synergism between pressure and temperature diminished, and the treatment temperature alone dominated DPA release. (III) Pressures pressure-induced physiological like germination with cortex degradation, which continues after pressure release. Furthermore, at 600 MPa and 40 °C, a linear relationship was found for the DPA release rate constants ln

5. Structural and functional analysis of a FeoB A143S G5 loop mutant explains the accelerated GDP release rate.

Guilfoyle, Amy P; Deshpande, Chandrika N; Vincent, Kimberley; Pedroso, Marcelo M; Schenk, Gerhard; Maher, Megan J; Jormakka, Mika

2014-05-01

GTPases (G proteins) hydrolyze the conversion of GTP to GDP and free phosphate, comprising an integral part of prokaryotic and eukaryotic signaling, protein biosynthesis and cell division, as well as membrane transport processes. The G protein cycle is brought to a halt after GTP hydrolysis, and requires the release of GDP before a new cycle can be initiated. For eukaryotic heterotrimeric Gαβγ proteins, the interaction with a membrane-bound G protein-coupled receptor catalyzes the release of GDP from the Gα subunit. Structural and functional studies have implicated one of the nucleotide binding sequence motifs, the G5 motif, as playing an integral part in this release mechanism. Indeed, a Gαs G5 mutant (A366S) was shown to have an accelerated GDP release rate, mimicking a G protein-coupled receptor catalyzed release state. In the present study, we investigate the role of the equivalent residue in the G5 motif (residue A143) in the prokaryotic membrane protein FeoB from Streptococcus thermophilus, which includes an N-terminal soluble G protein domain. The structure of this domain has previously been determined in the apo and GDP-bound states and in the presence of a transition state analogue, revealing conformational changes in the G5 motif. The A143 residue was mutated to a serine and analyzed with respect to changes in GTPase activity, nucleotide release rate, GDP affinity and structural alterations. We conclude that the identity of the residue at this position in the G5 loop plays a key role in the nucleotide release rate by allowing the correct positioning and hydrogen bonding of the nucleotide base. © 2014 FEBS.

6. Pregnancy rate in women with adenomyosis undergoing fresh or frozen embryo transfer cycles following gonadotropin-releasing hormone agonist treatment.

Park, Chan Woo; Choi, Min Hye; Yang, Kwang Moon; Song, In Ok

2016-09-01

To determine the preferred regimen for women with adenomyosis undergoing in vitro fertilization (IVF), we compared the IVF outcomes of fresh embryo transfer (ET) cycles with or without gonadotropin-releasing hormone (GnRH) agonist pretreatment and of frozen-thawed embryo transfer (FET) cycles following GnRH agonist treatment. This retrospective study included 241 IVF cycles of women with adenomyosis from January 2006 to January 2012. Fresh ET cycles without (147 cycles, group A) or with (105 cycles, group B) GnRH agonist pretreatment, and FET cycles following GnRH agonist treatment (43 cycles, group C) were compared. Adenomyosis was identified by using transvaginal ultrasound at the initial workup and classified into focal and diffuse types. The IVF outcomes were also subanalyzed according to the adenomyotic region. GnRH agonist pretreatment increased the stimulation duration (11.5±2.1 days vs. 9.9±2.0 days) and total dose of gonadotropin (3,421±1,141 IU vs. 2,588±1,192 IU), which resulted in a significantly higher number of retrieved oocytes (10.0±8.2 vs. 7.9±6.8, p=0.013) in group B than in group A. Controlled ovarian stimulation for freezing resulted in a significantly higher number of retrieved oocytes (14.3±9.2 vs. 10.0±8.2, p=0.022) with a lower dose of gonadotropin (2,974±1,112 IU vs. 3,421±1,141 IU, p=0.037) in group C than in group B. The clinical pregnancy rate in group C (39.5%) tended to be higher than those in groups B (30.5%) and A (25.2%) but without a significant difference. FET following GnRH agonist pretreatment tended to increase the pregnancy rate in patients with adenomyosis. Further large-scale prospective studies are required to confirm this result.

7. Preparation of Ibuprofen Sustained-release Tablet and Its Release Rate in Vitro%布洛芬缓释片的制备及其体外释放度考察

王平; 肖昌录; 袁训贤

2011-01-01

OBJECTIVE: To study and prepare Ibuprofen sustained-release tablets and to establish determination method for release rate of it in vitro. METHODS: Ibuprofen sustained-release tablet was prepared using hydrophilic gel framework material. The content of Ibuprofen sustained release tablets was determined by HPLC. Ac coding to stirring basket method stated in Chinese Pharmacopeia (2010 edition), phosphate buffer solution was used as solvent at rotating speed of 150 r·min-1 to determine release rate of 3 batches of samples in vitro. Repeatability of different batches and homogeneity of the same batch of samples (1, 3, 6, 8 h)were investigated. RESULTS: 3 batches of sustained-release tablet released completely within 8 h with sound repeatability. The RSDs of dissolution rate of the same batch of samples at 1, 3, 6, 8 h were 0.45％, 1.89％, 1.88％, 1.31％. There was small difference among different batches. CONCLUSION: Established preparation method is simple and stable, and the method for in vitro dissolution rate determination is convenient, rapid and easy to do.%目的:研制布洛芬缓释片并建立其体外释放度测定方法.方法:以亲水性凝胶骨架材料羟丙基甲基纤维素制备布洛芬缓释片.采用高效液相色谱法测定其含量,根据2010年版篮法,以磷酸盐缓冲液为溶出介质、转速为150 r·min-1测定3批样品的体外释放度,进行批闻重现性和同一批样品的均一性(1、3、6、8h)考察.结果:所制3批缓释片在8 h内释放基本完成,批间重现性良好;同一批样品在1、3、6、8 h各取样时间点,释放度的RSD值分别为0.45%、1.89%、1.88%、1.3l%,批间差异小.结论:布洛芬缓释片的制备方法简单、质量稳定,建立的体外释放度测定方法简便、快速,易于操作.

8. Therapeutically optimized rates of drug release can be achieved by varying the drug-to-lipid ratio in liposomal vincristine formulations.

Johnston, Michael J W; Semple, Sean C; Klimuk, Sandra K; Edwards, Katarina; Eisenhardt, Merete L; Leng, Esther C; Karlsson, Göran; Yanko, Daniel; Cullis, Pieter R

2006-01-01

The anti-tumor efficacy of liposomal formulations of cell cycle dependent anticancer drugs is critically dependent on the rates at which the drugs are released from the liposomes. Previous work on liposomal formulations of vincristine have shown increasing efficacy for formulations with progressively slower release rates. Recent work has also shown that liposomal formulations of vincristine with higher drug-to-lipid (D/L) ratios exhibit reduced release rates. In this work, the effects of very high D/L ratios on vincristine release rates are investigated, and the antitumor efficacy of these formulations characterized in human xenograft tumor models. It is shown that the half-times (T(1/2)) for vincristine release from egg sphingomyelin/cholesterol liposomes in vivo can be adjusted from T(1/2) = 6.1 h for a formulation with a D/L of 0.025 (wt/wt) to T(1/2) = 117 h (extrapolated) for a formulation with a D/L ratio of 0.6 (wt/wt). The increase in drug retention at the higher D/L ratios appears to be related to the presence of drug precipitates in the liposomes. Variations in the D/L ratio did not affect the circulation lifetimes of the liposomal vincristine formulations. The relationship between drug release rates and anti-tumor efficacy was evaluated using a MX-1 human mammary tumor model. It was found that the antitumor activity of the liposomal vincristine formulations increased as D/L ratio increased from 0.025 to 0.1 (wt/wt) (T(1/2) = 6.1-15.6 h respectively) but decreased at higher D/L ratios (D/L = 0.6, wt/wt) (T(1/2) = 117 h). Free vincristine exhibited the lowest activity of all formulations examined. These results demonstrate that varying the D/L ratio provides a powerful method for regulating drug release and allows the generation of liposomal formulations of vincristine with therapeutically optimized drug release rates.

9. Formulation of a modified release metformin. HCl matrix tablet: influence of some hydrophilic polymers on release rate and in-vitro evaluation

John Rojas

2011-09-01

Full Text Available Metformin hydrochloride is an antidiabetic agent which improves glucose tolerance in patients with type 2 diabetes and reduces basal plasma levels of glucose. In this study, a simplex centroid experimental design with 69 runs was used to select the best combination of some hydrophilic polymers that rendered a 24 h in-vitro release profile of metformin.HCl. The Korsmeyer-Peppas model was used to model the dissolution profiles since it presented the best fit to the experimental data. Further, a cubic model predicted the best formulation of metformin.HCl containing polyvinyl pyrrolidone, ethyl cellulose, hydroxypropyl methyl cellulose, carrageenan, sodium alginate, and gum arabic at 6.26, 68.7, 6.26, 6.26, 6.26 and 6.26 % levels, respectively. The validation runs confirmed the accuracy of the cubic model with six components for predicting the best set of components which rendered a once-a-day modified release hydrophilic matrix tablet in compliance with the USP specifications.O cloridrato de metformina é um agente antidiabético que melhora a tolerância à glicose em pacientes com diabetes tipo 2 e reduz os níveis plasmáticos basais de glicose. Neste estudo, um projeto experimental do tipo "centróide simplex" com 69 tomadas foi usado para selecionar a melhor combinação de alguns polímeros hidrofílicos que gerou um perfil de liberação da metformina.HCl de 24 horas. O modelo Korsmeyer-Peppas foi usado para modelar os perfis de dissolução, uma vez que apresentou os melhores ajustes aos dados experimentais. Além disso, um modelo cúbico previu a melhor formulação de metformina.HCl sendo aquela contendo polivinilpirrolidona, etilcelulose, hidroxipropilmetil celulose, carragena, alginato de sódio e goma arábica nos níveis 6.26, 68.7, 6.26, 6.26, 6.26 e 6.26 %, respectivamente. As corridas de validação confirmaram a precisão do modelo cúbico com os seis componentes para prever o melhor conjunto de componentes que originou uma

10. Effect of adding self-emulsifying excipients on release rate of tetramethylpyrazine-release solid dispersion%自乳化辅料对川芎嗪缓释固体分散体释放度的影响

王利胜; 陈晓丹; 吕耿彬; 涂星; 吴俊洪

2012-01-01

Objective: To determine the effect of adding self-emulsifying excipients on release rate of tetramethylpyrazine-release solid dispersion (TMP-SD).Methods: The in vitro dissolution between TMP-SD and tetramethylpyrazine-release self-emulsifying solid dispersion (TMP-SESD) was compared.Results: The cumulative release rate of TMP-SD was (39.26±1.86)% within 12 h, whereas that of TMP-SESD was (98.33 ± 2.02)% .Conclusion: Addition of self-emulsifying excipients to the TMP-SD can greatly increase the drug release rate.%目的:考察自乳化辅料的加入对川芎嗪缓释固体分散体释放度的影响,为剂型的改进提供一定的依据.方法:HPLC法测定川芎嗪缓释固体分散体(tetramethylpyrazine solid dispersion,TMP-SD)与川芎嗪自乳化缓释固体分散体(tetramethylpyrazine self-emulsifying solid dispersion,TMP-SESD)的累积释放度,比较二者的释药特征.结果:TMP-SD 12 h释放量仅为(39.26±1.86)％,而TMP-SESD释放量可达(98.33±2.02)％.结论:自乳化辅料的加入解决了TMP-SD释放度过低的问题,达到理想的释药效果.

11. Influence of the ionic character of a drug on its release rate from hydrogels based on 2-hydroxyethylmethacrylate and acrylamide synthesized by photopolymerization

M. L. Gomez

2012-03-01

Full Text Available The influence of the ionic character of a specific drug on its release rate from a hydrogel based on 2-hydroxyethylmethacrylate (HEMA and acrylamide (AAm is analyzed. The hydrogel was synthesized by photopolymerization employing visible light, safranine O (Saf, as sensitizer, and a silsesquioxane functionalized with amine and methacrylate groups (SFMA, as co-initiator and crosslinker. Safranine O (Saf was employed as a model of a cationic drug and the anionic form of resorufin (Rf as a model of an anionic drug. Saf exhibited a larger affinity with functional groups of the hydrogel than that of Rf. This produced a lower loading and a faster release rate of Rf with respect to Saf. Besides, the release rate of Rf followed a Fickian behavior, while that of Saf exhibited a non-Fickian behavior. By hydrolyzing the hydrogel at pH = 13, amide groups supplied by AAm were irreversibly converted into carboxylic acid groups. Higher loadings and slower release rates of Saf from the hydrolyzed hydrogels were observed, making them particularly suitable for the slow drug-delivery of cationic drugs.

12. Effect of precipitation, sorption and stable of isotope on maximum release rates of radionuclides from engineered barrier system (EBS) in deep repository.

Malekifarsani, A; Skachek, M A

2009-10-01

The basic function of the engineered barrier system (EBS) in geological disposal is to prevent or limit the release of radionuclides into the underground environment. For this purpose, the vitrified waste is contained in an overpack to isolate it from contact with groundwater for a certain initial period of time. However, it is impossible to ensure complete containment for all time. Therefore, the eventual release of nuclides must be minimized after the overpack fails (AEC, 1984. Radioactive waste processing and disposal measures; JNC, 2000a. Project to establish the scientific and technical basis for HLW disposal in Japan--first progress report-H3. Geological Environment in Japan, JNC TN1410 2000-002; JNC, 2000b. H12: project to establish the scientific and technical basis for HLW disposal in Japan--repository design and engineering technology, JNC TN1410 2000-003.). Low-permeability buffer material is installed between the overpack and the host rock to ensure that radionuclide release from the vitrified waste is limited by diffusive transport rather than advective transport in groundwater. Nuclides released from the waste form precipitate when their concentrations in the porewater result in their elemental solubility limits being exceeded. This limits the concentrations of many nuclides in the buffer and thus limits the release rates to the surrounding rock. High sorption coefficients act to delay the transport of certain nuclides during their migration through the buffer (PNC, development and management of the technical knowledge base for the geological disposal of HLW. Supporting report 2: repository engineering technology). The presence of isotopes of the same element has the effect of reducing the effective solubility of some nuclides; a lower nuclide concentration is required for precipitation to occur if the presence of any isotopes of the same element is taken into account. The calculated release rates of radionuclides from the EBS (per waste package) are

13. Poly(ethylene glycol)-poly(lactic-co-glycolic acid) core-shell microspheres with enhanced controllability of drug encapsulation and release rate.

Cha, Chaenyung; Jeong, Jae Hyun; Kong, Hyunjoon

2015-01-01

Poly(lactic-co-glycolic acid) (PLGA) microspheres have been widely used as drug carriers for minimally invasive, local, and sustained drug delivery. However, their use is often plagued by limited controllability of encapsulation efficiency, initial burst, and release rate of drug molecules, which cause unsatisfactory outcomes and several side effects including inflammation. This study presents a new strategy of tuning the encapsulation efficiency and the release rate of protein drugs from a PLGA microsphere by filling the hollow core of the microsphere with poly(ethylene glycol) (PEG) hydrogels of varying cross-linking density. The PEG gel cores were prepared by inducing in situ cross-linking reactions of PEG monoacrylate solution within the PLGA microspheres. The resulting PEG-PLGA core-shell microspheres exhibited (1) increased encapsulation efficiency, (2) decreased initial burst, and (3) a more sustained release of protein drugs, as the cross-linking density of the PEG gel core was increased. In addition, implantation of PEG-PLGA core-shell microspheres encapsulated with vascular endothelial growth factor (VEGF) onto a chicken chorioallantoic membrane resulted in a significant increase in the number of new blood vessels at an implantation site, while minimizing inflammation. Overall, this strategy of introducing PEG gel into PLGA microspheres will be highly useful in tuning release rates and ultimately in improving the therapeutic efficacy of a wide array of protein drugs.

14. A GTPase chimera illustrates an uncoupled nucleotide affinity and release rate, Providing insight into the activation mechanism

Guilfoyle, Amy P.; Deshpande, Chandrika N.; Font Sadurni, Josep;

2014-01-01

The release of GDP from GTPases signals the initiation of a GTPase cycle, where the association of GTP triggers conformational changes promoting binding of downstream effector molecules. Studies have implicated the nucleotide-binding G5 loop to be involved in the GDP release mechanism. For example......, biophysical studies on both the eukaryotic Gα proteins and the GTPase domain (NFeoB) of prokaryotic FeoB proteins have revealed conformational changes in the G5 loop that accompany nucleotide binding and release. However, it is unclear whether this conformational change in the G5 loop is a prerequisite...... GTPase activity at a similar level to wild-type NFeoB, and structural analyses of the nucleotide-free and GDP-bound proteins show that the G5 loop adopts conformations analogous to that of the human nucleotide-bound Giα1 protein in both states. Interestingly, isothermal titration calorimetry and stopped...

15. Short-term Outcomes following Concussion in the NFL: An 11-year Retrospective Study of Player Release Rate and Financial Loss

Ramkumar, Prem; Navarro, Sergio Michael

2017-01-01

Objectives: The primary goal of this study was to assess the short-term outcomes among National Football League (NFL) players following concussion in terms of: (1) DNP protocol activation, (2) release rate at one and three years, and (3) mean salary reduction. A secondary goal of the study was to stratify the post-concussive release rate by franchise and player position. Methods: NFL player transaction records and publicly available weekly injury reports from August 2005 to January 2016 for NFL players were analyzed. All players immediately sustaining recorded concussions were evaluated for a change to inactive or do-not-play (DNP) status. The one-year and three-year release rate following concussion was defined as any player transitioning to inactivation, retirement, free agency, or any failure to return for a successive season on the same team’s active roster after one or three years from the initial concussion. Student’s t-test was used to compare release rates between non-concussed and concussed players at one and three years. Mean salary reduction per year following concussion was calculated using publicly available player contracts. Additionally, franchise-level and position-based analyses of the release rate were performed. Results: Of the total 5,451 NFL players retrospectively analyzed over the 11-year period, 373 sustained publicly reported concussions resulting in DNP protocol activation. The release rate of the post-concussive versus non-concussive player was 26% vs. 20% at 1 year (p<0.01) and 31% vs. 19% at 3 years (p<0.01). After analyzing individual player contracts, the mean year-over-year change in contract value for concussed players after DNP protocol activation was an overall salary reduction of $760,000/year ±$2,380,000. Figure 1 depicts the tendency of each NFL franchise to release an athlete following concussion within one and three years. Table 1 reports a position-based analysis in terms of concussion rate, mean salary reduction, and

16. The effect of treatment with a slow-releasing oxytocin preparation at the onset of oestrus on the ovulation rate of Merino ewes : research note

P.R. King

1997-07-01

Full Text Available The effect of a slow-releasing oxytocin preparation on the ovulation rate of Merino ewes was investigated. Synchronised Merino ewes were subcutaneously injected with a slow-re-leasing preparation containing 10 IU oxytocin, 48 hours after sponge withdrawal. Laparo-scopic examination of the ovaries of all ewes was performed 10 d after the oxytocin treatment in order to determine the number of corpora lutea per ewe. The ovulation rate of the adult ewes of the treated and control groups was 179.1 % and 159.1 % respectively (p < 0.05 while that of the 2-tooth ewes was 108.3 % and 112.8 % respectively (p > 0.05. It would appear that a higher ovulation rate can be obtained by a single injection of a slow-releasing oxytocin preparation at the onset of oestrus. The lack of response in the 2-tooth ewes was probably due to their relatively low body weight.

17. 布洛芬缓释微丸的制备及释放度研究%PREPARATION AND STUDY ON RELEASE RATE OF SUSTAINED-RELEASE PELLETS OF IBUPROFEN

白翠莲; 孙虹; 许丽萍

2015-01-01

Objective:To prepare ibuprofen sustained-release pellets. Methods:Blank cores were prepared by means of powder layering with the PDL-Ⅱequipment,ibuprofen pellets were coated in the same equipment. Various factors influence on release rate and the release mechanism of the drug from the pellets was studied. Results:The optimal formula of the ibuprofen sustained release pellets were the following:pill core 100g,ibuprofen 300g,stearic acid 3g,PVP K 306g,and the dissolution test in vitro showed that they can meet with ibuprofen sustained release capsules launched. Release mechanism of the drug from pellets was in accordance with Higuchi equation:Q=-14. 814+38. 480t1/2(r=0. 996). Conclusions:The method and the formulation are successful in providing slow and steady release of ibuprofen from sustained-release pellets.%目的：：制备布洛芬缓释微丸。方法：采用DPL-Ⅱ多功能制粒包衣机制备微晶纤维素空白丸芯和布洛芬含药微丸。用释放度测定法考察影响药物释放的各种因素,并对布洛芬缓释微丸体外释药机理进行研究。结果：布洛芬缓释微丸最佳处方为：丸芯100g、布洛芬300g、硬脂酸3g、PVP K 306 g,其释放度与市售产品(芬必得)拟合良好,体外释药过程基本符合Higuchi 方程：Q=-14.814+38.480t1/2(r=0.996)。结论：成功的制备了布洛芬缓释微丸。

18. Evaluation of Gamma Fluence Rate Predictions for 41-argon Releases to the Atmosphere at a Nuclear Research Reactor Site

Rojas-Palma, Carlos; Aage, Helle Karina; Astrup, Poul

2004-01-01

An experimental study of radionuclide dispersion in the atmosphere has been conducted at the BR1 research reactor in Mol, Belgium. Artificially generated aerosols ('white smoke') were mixed with the routine releases of Ar-41 in the reactor's 60-m tall venting stack. The detailed plume geometry...

19. Unexpectedly high catch-and-release rates in European marine recreational fisheries: implications for science and management

Ferter, K.; Weltersbach, M.S.; Strehlow, H.V.; Graaf, de M.; Hammen, van der T.

2013-01-01

While catch-and-release (C&R) is a well-known practice in several European freshwater recreational fisheries, studies on the magnitude and impact of this practice in European marine recreational fisheries are limited. To provide an overview of the practice and magnitude of C&R among marine

20. Evaluation of Gamma Fluence Rate Predictions for 41-argon Releases to the Atmosphere at a Nuclear Research Reactor Site

Rojas-Palma, Carlos; Aage, Helle Karina; Astrup, Poul

2004-01-01

An experimental study of radionuclide dispersion in the atmosphere has been conducted at the BR1 research reactor in Mol, Belgium. Artificially generated aerosols ('white smoke') were mixed with the routine releases of Ar-41 in the reactor's 60-m tall venting stack. The detailed plume geometry...

1. In vitro release testing of matrices based on starch-methyl methacrylate copolymers: effect of tablet crushing force, dissolution medium pH and stirring rate.

Ferrero, C; Jiménez-Castellanos, M R

2014-01-30

Direct-compressed matrix tablets were obtained from a variety of potato starch-methyl methacrylate copolymers(1) as sustained-release agents, using anhydrous theophylline as a model drug. The aim of this work was to investigate the influence of the copolymer type, the tablet crushing force and dissolution variables such as the pH of the dissolution medium and the agitation intensity on the in vitro drug release behaviour of such matrices. Commercial sustained-release theophylline products (Theo-Dur(®) 100mg, Theolair(®) 175 mg) were used as standards. Test formulations were compacted into tablets at three different crushing force ranges (70-80, 90-100 and 110-120 N) to examine the effect of this factor on the porous network and drug release kinetics. In vitro release experiments were conducted in a pH-changing medium (1.2-7.5) with basket rotation speeds in the range 25-100 r.p.m. to simulate the physiological conditions of the gastrointestinal tract. The release rate of theophylline was practically not affected by pH in the case of Theo-Dur(®) and HSMMA matrices. In contrast, Theolair(®) and CSMMA tablets demonstrated a biphasic drug release pattern, which appeared to be sensitive to the pH of the dissolution medium. An increase in the crushing force of the copolymer matrices was accompanied by a reduction of the matrix porosity, although the porous network depends markedly on the type of copolymer, having a strong influence on the drug release kinetics. Mathematical modelling of release data shows a Fickian diffusion or anomalous transport mechanism. Based on the similarity factor f2, FD-HSMMA, OD-CSMMA and FD-CSMMA at 90-100 N were selected for agitation studies. In general, all formulations showed an agitation speed-dependent release, with Theo-Dur(®) and FD-CSMMA matrices being the less susceptible to this factor. Copyright © 2013 Elsevier B.V. All rights reserved.

2. A novel nuclear magnetic resonance (NMR) imaging method for measuring the water front penetration rate in hydrophilic polymer matrix capsule plugs and its role in drug release.

Ashraf, M; Iuorno, V L; Coffin-Beach, D; Evans, C A; Augsburger, L L

1994-05-01

An NMR imaging method was developed to estimate the rate of water movement in slow-release capsule matrices of pseudoephdrine HCl and hydroxypropyl cellulose (HPC). Test capsules were first placed in a USP method 2 (paddles, 50 rpm) dissolution apparatus. Each plug was removed from the dissolution medium at predetermined times, blotted dry, and placed within the magnetic field of a General Electric 400-MHz wide-bore NMR spectrometer equipped with a microimaging accessory. Images were recorded along the transverse plane of each plug. The water penetration rate was determined by comparison of the cut and weighed contour plots of the images acquired. After 1 hr, the plugs tamped to 200 N exhibited water penetration to the center, while only 45% of the drug was released. The percentage dry matrix was fitted to the Jost equation to obtain a diffusion coefficient of 4.15 x 10(-6) cm2/sec. NMR imaging is set forth as an important and practicable technique to investigate drug formulations. In the HPC matrix system of this study, the NMR imaging results convincingly revealed the rate of hydration front penetration not to be a rate-limiting step in the drug release process.

3. Variable responses by southern pine beetle, Dendroctonus frontalis Zimmermann, to the pheromone component endo-brevicomin: influence of enantiomeric composition, release rate, and proximity to infestations.

Sullivan, Brian T; Dalusky, Mark J; Mori, Kenji; Brownie, Cavell

2011-04-01

The male-produced bicyclic acetal endo-brevicomin is a component of the pheromone blend that mediates colonization of host pines by the bark beetle Dendroctonus frontalis Zimmermann. Efforts to identify its behavioral function have been complicated by contrasting reports that it either enhances or reduces attraction of flying beetles. Our studies failed to support the hypothesis that this published variability is due to differences in release rate and/or the enantiomeric composition [i.e., the beetle-produced (+)-enantiomer vs. the racemate] of the endo-brevicomin used in the experiments. In trapping trials within active D. frontalis infestations, racemic and (+)-endo-brevicomin did not differ from each other in behavioral effects when tested at seven different release rates ranging from 0.005 to 3 mg/d. At the highest release rates, racemic and (+)-endo-brevicomin similarly reduced catches in traps baited with an attractant (frontalin and turpentine), but neither enhanced catches at any release rate. Furthermore, the activity of racemic endo-brevicomin baits depended on trap proximity to D. frontalis infestations. Addition of these baits to attractant-baited traps located inside active infestations reduced catches, but they enhanced catches at traps located either 100 or 200 m outside these infestations. The contrasting responses may reflect differences in host-seeking strategies by either aggregated or dispersing D. frontalis, and may be elicited by differing abundance of natural sources of semiochemicals or differing responsiveness of beetles inside vs. outside of infestations. We suspect that much of the published variability in D. frontalis responses to endo-brevicomin is attributable to differing proximity of experimental field sites to infestations.

4. The influence of hydrophylic polymers on the release rate of calcium dobesilate in hydrogel formulation assessed in vitro using porcine ear skin

Wojcik-Pastuszka Dorota

2015-12-01

Full Text Available A shortage of available experimental data exists in the available bibliography on the release rate of calcium dobesilate (CD from hydrogel formulations. Thus, the aim of the study was to evaluate the effect of selected hydrophilic nonionic polymers and anionic polymers on the release rate of CD from formulation provided for dermal application, as compared to the reference product in the market. The work utilized excised pork skin, while, Methylcellulose (MC, hydroxypropyl methylcellulose (HPMC, and anionic polymers (copolymers of acrylic acid were used as CD carriers. The release study was executed by the pharmacopoeial paddle method, with extraction cells and fresh excised porcine skin as a membrane. CD in aqueous acceptor fluid was quantified by UV-VIS spectrometry at 300 nm. Subsequently, the kinetic curves were fitted to a zero-order kinetics model, a first-order kinetics model, a second-order kinetics model, as well as to the Higuchi model. The work saw that porcine ear skin influences the release pattern of the CD, compared to the artificial membrane. In the study, the evaluated formulations with MC, polyacrylic acid (PA and polyacrylate crosspolymer 11 (PC-11 deliver over 60% of the active component (AC, within 250 min, through the excised porcine ear skin, to the acceptor compartment. Moreover, the release observed via porcine ear skin to the aqueous acceptor compartment is congenial to zero-order or first-order kinetics. In addition, the formulations prepared on the basis of MC and PA appear to control AC delivery, independently of actual concentration of AC.

5. Determination of the releasing rate of Compound Doxycycline Sustained-release Gel in vivo%复方多西环素缓释凝胶的体内释放度测定

程凤峡; 张海芳; 杨玉鹏; 田华; 刘勇

2014-01-01

Objective To observe the releasing rate in vivo of Compound Doxycycline Sustained-release Gel. Methods 11 patients were enrolled in and 26 teeth were divided into Experimental group and Control group .After one week of initial treatment ,the periodontal pockets of defective teeth in Control group were injected Compound Doxycycline Gel and those in experimental group were injected Compound Doxycycline Sustained-release Gel.Gingival crevicular fluid ( GCF ) samples were collected every day by filter strip after administering medicine ,and the concentration of doxycycline in GCF was tested by HPLC.Results The concentration of doxycycline in GCF decreased to 6.82μg/ml on the third day of treatment with Compound Doxycycline Gel;while the concentration of doxycycline in GCF could still maintain at 60 .46μg/ml on the seventh day after the treatment with Compound Doxycycline Sustained-release Gel.Conclusion Compound Doxycycline Sustained-release gel can be slowly released in periodontal pocket , and the doxycycline can be maintained at an effective concentration within a long time.%目的：观察复方多西环素缓释凝胶的体内缓释性能。方法将11名患者的26颗患牙随机分为实验组和对照组，于基础治疗1周后，分别在牙周袋内置入复方多西环素缓释凝胶和复方多西环素凝胶，并于置药后每天定时用滤纸条法采集龈沟液样本，高效液相色谱法测定龈沟液内多西环素的浓度。结果复方多西环素凝胶在用药后第3天，龈沟液内多西环素浓度已降至6．82μg/ml；复方多西环素缓释凝胶在用药7 d后龈沟液内多西环素浓度仍可达到60．46μg/ml。结论复方多西环素缓释凝胶在牙周袋内可缓慢释放，较长时间维持有效浓度。

6. STEADY-STATE FLAMMABLE GAS RELEASE RATE CALCULATION AND LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

HU TA

2007-10-26

Assess the steady-state flammability level at normal and off-normal ventilation conditions. The methodology of flammability analysis for Hanford tank waste is developed. The hydrogen generation rate model was applied to calculate the gas generation rate for 177 tanks. Flammability concentrations and the time to reach 25% and 100% of the lower flammability limit, and the minimum ventilation rate to keep from 100 of the LFL are calculated for 177 tanks at various scenarios.

7. Modulation of drug release rate of diltiazem-HCl from hydrogel matrices of succinic acid-treated ispaghula husk.

Gohel, M C; Amin, A F; Chhabaria, M T; Panchal, M K; Lalwani, A N

2000-01-01

The feasibility of using succinic acid-treated ispaghula husk in matrix-based tablets of diltiazem-HCl was investigated. The sample prepared using 4:1 weight ratio of ispaghula husk to succinic acid showed improved swelling and gelling. A 3(2) factorial design was employed to investigate the effect of amount of succinic acid-treated ispaghula husk and dicalcium phosphate (DCP) on the percentage of the drug dissolved in 60, 300, and 480 min from the compressed tablets. The results of multiple linear regression analysis revealed that the significance of the amount of succinic acid-treated ispaghula husk was greater in magnitude than that of the amount of DCP in controlling the drug release. Acceptable batches were identified from a contour plot with constraints on the percentage drug released at the three sampling times. A mathematical model was also evolved to describe the entire dissolution profile. The results of F-test revealed that the Higuchi model fits well to the in vitro dissolution data. The tablets showed considerable radial and axial swelling in distilled water. Succinic acid-treated ispaghula husk can be used as an economical hydrophilic matrixing agent.

8. Effects of heat release rate on NOx time history in diesel combustion; Diesel nensho ni okeru netsu hasseiritsu keika ga NOx nodo rireki ni oyobosu eikyo

Ishiyama, T.; Miwa, K.; Higashida, M. [Tokushima Univ., Tokushima (Japan). Faculty of Engineering; Watanabe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1996-06-25

For determining the optimum combination of combustion control techniques to reduce NOx emission from diesel engines, it is important to clarify the effects of each technique not only on the NOx emission but also on its time history during combustion. In this paper, NOx concentration in the combustion chamber of a rapid compression machine has been measured by using a total gas sampling method. In order to elucidate the relation between NOx history and heat release rate, air temperatures nozzle hole size and air motion are varied to control the heat release process. The results show that NOx emission is not solely dependent upon initial combustion. Air utilization in the main diffusive combustion phase has great influence on NOx formation and its decay. NOx formation is accelerated by activation of the initial stage of the main combustion when using a nozzle with small holes. 9 refs., 13 figs.

9. Stellar masses, star formation rates, metallicities and AGN properties for 200,000 galaxies in the SDSS Data Release Two (DR2)

Brinchmann, J; Heckman, T M; Kauffmann, G; Tremonti, C A; White, S D M; Brinchmann, Jarle; Charlot, Stephane; Heckman, Timothy M.; Kauffmann, Guinevere; Tremonti, Christy; White, Simon D.M.

2004-01-01

By providing homogeneous photometric and spectroscopic data of high quality for very large and objectively selected samples of galaxies, the Sloan Digital Sky Survey allows statistical studies of the physical properties of galaxies and AGN to be carried out at an unprecedented level of precision and detail. Here we publicly release catalogues of derived physical properties for 211,894 galaxies, including 33,589 narrow-line AGN. These are complete samples with well understood selection criteria drawn from the normal galaxy spectroscopic sample in the second SDSS public data release (DR2). We list properties obtained from the SDSS spectroscopy and photometry using modelling techniques presented in papers already published by our group. These properties include: stellar masses; stellar mass-to-light ratios; attenuation of the starlight by dust; indicators of recent major starbursts; current total and specific star-formation rates, both for the regions with spectroscopy and for the galaxies as a whole; gas-phase ...

10. Drought stress release increased growth rate but did not affect levels of storage carbohydrates in Scots pine trees

Schönbeck, Leonie; Gessler, Arthur; Rigling, Andreas; Schaub, Marcus; Li, Mai-He

2017-04-01

For trees, energy storage in the form of non-structural carbohydrates (NSCs) plays an important role for survival and growth, especially during stress events such as drought. It is hypothesized, that tree individuals that experience long-term drought stress use up larger amounts of NSCs than trees that do not experience drought. Consequently, such drought-induced depletion might lead to a decrease in tree vigor and carbon starvation, a mechanism that is subject of intensive debates in recent literature. Hence, if carbon starvation is occurring during drought, drought stress release should again increase NSC concentrations. A long-term (13 years) irrigation experiment is being conducted in the Pfyn forest, the largest Pinus sylvestris dominated forest in Switzerland, located in the dry inner-Alpine Swiss Rhone valley (average precipitation 600 mm/year, with frequent dry spells). Water addition ( 600 mm/year) is executed every year during the growing season between April and October. Tree height, stem diameter and crown transparency are being measured since 2003. In February, July and October 2015, roots, stem sapwood and needles were harvested from 30 irrigated and 30 control trees and 5 different crown transparency classes. Shoot length, needle morphology, soluble sugars, starch concentrations, needle δ13C and δ15N were measured. Shoot and stem growth were higher in irrigated trees than in control trees. Growth decreased with increasing crown transparency in both treatments. Only in July, needle starch levels were higher in irrigated trees than in control trees but there was no treatment effect for wood and root starch concentrations. Tissue starch and sugar levels were negatively correlated with crown transparency, particularly in the roots (p<0.001), independent of the treatment. Needle δ13C values were higher in the control trees than in the irrigated trees, where needle δ13C values were positively correlated with increasing transparency (p<0.01). Annual

11. 近红外透射光谱法快速测定布洛芬缓释胶囊释放度%Rapid determination of ibuprofen sustained-release capsule releasing rate using near infrared transmission spectroscopy technology

王小亮; 贾建忠; 杨欣; 刘雪峰

2012-01-01

目的:利用近红外透射光谱分析技术和化学计量学方法对布洛芬缓释胶囊释放度进行快速定量分析.方法:以30批布洛芬缓释胶囊为分析对象,首先用近红外透射光谱法采集不同时间段释放液的近红外透射光谱,并以高效液相色谱法测定其含量,最后采用偏最小二乘法建立释放度定量测定模型.结果:30批布洛芬缓释胶囊释放度实验得到101个样品数据,采用外部验证建立模型.根据自动分离原理,从101个样品数据中选择了61个数据作为校正集样本,含量范围为4.97％～30.89％；剩余40个数据作为验证集样本,含量范围为5.07％ ～30.34％；建模谱段为8937 ～7487 cm-1及6102 ～5446 cm-1；预处理方法为一阶导加多元散射校正；维数为6；内部验证及外部验证的相关系数分别为95.04％和94.37％；内部交叉验证及外部验证均方根误差分别为1.96％和2.04％.结论:所建立的释放度快速分析定量模型可对布洛芬制剂进行准确、快速定量分析,方法快速简便,可用于药品的快速分析和检验.%Objective: To quantitatively analyze the releasing rate of ibuprofen sustained - release capsules by near infrared transmission spectroscopy technology and chemometrics. Methods:A total of 30 batches of ibuprofen sustained - release capsules were chosen for analysis. First,the near infrared spectrum of the releasing liquid of ibuprofen sustained -release capsules was collected in different periods. Then,the active pharmaceutical ingredient(API) contents were determined by HPLC. Finally, the releasing rate quantitative model with the partial least square { PLS) algorithm available in the Quant 2 was developed. Results:Our model was based on 101 data obtained from 30 batches of samples, which included 61 data in calibration set with the API ranged from 4. 97% - 30. 89% , and 40 data in test set with the API from 5.07% - 30. 34% . The spectra ranges were 8937 - 7487 cm-1

12. Heterogeneity of rat FSH by chromatofocusing: studies on serum FSH, hormone released in vitro and metabolic clearance rates of its various forms.

Blum, W F; Gupta, D

1985-04-01

Rat pituitary FSH was fractionated by chromatofocusing between pH 6 and 3. Ten components were resolved having apparent isoelectric points between 3.1 and 5.1. A comparative study of pituitary FSH and FSH secreted in vitro by quartered pituitary glands in the presence and in the absence of gonadotrophin-releasing hormone (GnRH) revealed similar patterns of charged species of intracellular and released FSH. Although GnRH increased FSH secretion about fourfold, no influence on the pattern of charged species was observed. Utilizing exclusion chromatography and chromatofocusing, pituitary FSH was compared to serum FSH which had been extracted by immuno-affinity chromatography. The results demonstrate for serum FSH a larger molecular size and a relative shift to more acidic components. Metabolic clearance rates of eight FSH components separated by chromatofocusing were measured in adult male rats. Half-lives varied between 13 min and several hours. A correlation existed between decrease of isoelectric points and decrease of metabolic clearance rates. These findings suggest that all hypophysial FSH components are secreted into the circulation at similar rates and the more acidic FSH components which appear to contain increased sialic acid, have a longer circulatory half-life and are more abundant in serum. It is concluded that sialylation may be involved in modulating serum FSH levels.

13. The biowaiver extension for BCS class III drugs: the effect of dissolution rate on the bioequivalence of BCS class III immediate-release drugs predicted by computer simulation.

Tsume, Yasuhiro; Amidon, Gordon L

2010-08-02

The Biopharmaceutical Classification System (BCS) guidance issued by the FDA allows waivers for in vivo bioavailability and bioequivalence studies for immediate-release (IR) solid oral dosage forms only for BCS class I drugs. However, a number of drugs within BCS class III have been proposed to be eligible for biowaivers. The World Health Organization (WHO) has shortened the requisite dissolution time of BCS class III drugs on their Essential Medicine List (EML) from 30 to 15 min for extended biowaivers; however, the impact of the shorter dissolution time on AUC(0-inf) and C(max) is unknown. The objectives of this investigation were to assess the ability of gastrointestinal simulation software to predict the oral absorption of the BCS class I drugs propranolol and metoprolol and the BCS class III drugs cimetidine, atenolol, and amoxicillin, and to perform in silico bioequivalence studies to assess the feasibility of extending biowaivers to BCS class III drugs. The drug absorption from the gastrointestinal tract was predicted using physicochemical and pharmacokinetic properties of test drugs provided by GastroPlus (version 6.0). Virtual trials with a 200 mL dose volume at different drug release rates (T(85%) = 15 to 180 min) were performed to predict the oral absorption (C(max) and AUC(0-inf)) of the above drugs. Both BCS class I drugs satisfied bioequivalence with regard to the release rates up to 120 min. The results with BCS class III drugs demonstrated bioequivalence using the prolonged release rate, T(85%) = 45 or 60 min, indicating that the dissolution standard for bioequivalence is dependent on the intestinal membrane permeability and permeability profile throughout the gastrointestinal tract. The results of GastroPlus simulations indicate that the dissolution rate of BCS class III drugs could be prolonged to the point where dissolution, rather than permeability, would control the overall absorption. For BCS class III drugs with intestinal absorption patterns

14. [Nitrogen uptake rate and use efficiency by rice under different levels of the controlled-release N fertilizers (CRF) in the Nansi Lake basin].

Zhang, Qing-Wen; Du, Chun-Xiang; Li, Xiao-Wei; Li, Gui-Chun; Wang, Ming

2011-07-01

The nitrogen (N) fertilizers overused or misused are the main contributors for water eutrophication of the Nansi Lake in eastern China. A field experiment with different application levels of controlled-release N fertilizer (CRF) was carried out at a rice field in the Nansi lake basin to provide information on the nitrogen uptake rate and use efficiency by rice with CRF application at different growth stages of rice. The fertilization levels for the controlled fertilizer in this study were 0, 300, 337.5 and 375 kg/hm2, respectively, and 375 kg/hm2 for conventional urea (CU). We estimated the N uptake rate in different growing season and apparent recovery of fertilizer in root, stover and grain of rice. The result showed that grain yield increased by higher N rate. However, the N uptake rate did not increase linearly with the nitrogen application amount. The highest N uptake rate was 22.48 mg/(plant x d) under the fertilization amount of 337.5 kg/hm2 during the young panicle differentiation stage. Apparent N recovery efficiency for CU with traditional application amount of 375 kg/hm2 was 21.86%. Apparent N recovery efficiency for CRF with application amount of 337.5 kg/hm2 was highest with 37.17%. Based on the statistical data, with CU of traditional urea application amount of 375 kg/hm2, nitrogen loss and soil N residue at one growing season are 130.07 x 10(3) t for Jining city and 11.4 x 10(3) t for Yutai county of the Nansi Lake basin. If using CRF with the optimized application amount of 337.5 kg/hm2, nitrogen loss and soil residual at one growing season is 10.46 x 10(4) t for Jining city. It could reduce losses of 2.55 x 10(4) t N for Jining city and 2 235.26 t N for Yutai county per year. Because of releasing patterns more closely matched to crop N uptake patterns, controlled release N fertilizer could be a good way to prevent water eutrophication due to nitrogen fertilizer overused or misused in the Nansi Lake.

15. COMBUSTION HEAT RELEASE RATE ANALYSIS OF C.I. ENGINE WITH SECONDARY CO-INJECTION OF DEE-H2O SOLUTION - A VIBRATIONAL APPROACH

Y. V. V. SATYANARAYANA MURTHY

2015-08-01

Full Text Available This paper discusses the combustion propensity of single cylinder direct injection engine fueled with palm kernel methyl ester (PKME, which is non- edible oil and a secondary co-injection of saturated Diethyl ether (DEE with water. DEE along with water is fumigated through a high pressure nozzle fitted to the inlet manifold of the engine and the flow rate of the secondary injection was electronically controlled. DEE is known to improve the cold starting problem in engines when used in straight diesel fuel. However, its application in emulsion form is little known. Experimental results show that for 5% DEE- H2O solution injection, occurrence of maximum net heat release rate is delayed due to controlled premixed combustion, which normally helped in better torque conversion when the piston is in accelerated mode. Vibration measurements in the frequency range of 900Hz to 1300Hz revealed that a new mode of combustion has taken place with different excitation frequencies.

16. Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion.

Rodriguez, Omar; Matinmanesh, Ali; Phull, Sunjeev; Schemitsch, Emil H; Zalzal, Paul; Clarkin, Owen M; Papini, Marcello; Towler, Mark R

2016-12-01

Silica-based and borate-based glass series, with increasing amounts of TiO₂ incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion) closer to the substrate's (Ti6Al4V) CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO₂ in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO₂ to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO₂ incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass(®) and Pyrex.

17. Exploitation of 3D face-centered cubic mesoporous silica as a carrier for a poorly water soluble drug: Influence of pore size on release rate

Zhu, Wenquan; Wan, Long; Zhang, Chen; Gao, Yikun; Zheng, Xin; Jiang, Tongying; Wang, Siling, E-mail: silingwang@syphu.edu.cn

2014-01-01

The purposes of the present work were to explore the potential application of 3D face-centered cubic mesoporous silica (FMS) with pore size of 16.0 nm as a delivery system for poorly soluble drugs and investigate the effect of pore size on the dissolution rate. FMS with different pore sizes (16.0, 6.9 and 3.7 nm) was successfully synthesized by using Pluronic block co-polymer F127 as a template and adjusting the reaction temperatures. Celecoxib (CEL), which is a BCS class II drug, was used as a model drug and loaded into FMS with different pore sizes by the solvent deposition method at a drug–silica ratio of 1:4. Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen adsorption, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) was used to systematically investigate the drug loading process. The results obtained showed that CEL was in a non-crystalline state after incorporation of CEL into the pores of FMS-15 with pore size of 16.0 nm. In vitro dissolution was carried out to demonstrate the effects of FMS with different pore sizes on the release of CEL. The results obtained indicated that the dissolution rate of CEL from FMS-15 was significantly enhanced compared with pure CEL. This could be explained by supposing that CEL encountered less diffusion resistance and its crystallinity decreased due to the large pore size of 16.0 nm and the nanopore channels of FMS-15. Moreover, drug loading and pore size both play an important role in enhancing the dissolution properties for the poorly water-soluble drugs. As the pore size between 3.7 and 16.0 nm increased, the dissolution rate of CEL from FMS gradually increased. - Highlights: • Exploitation of 3D cubic mesoporous silica (16 nm) as a carrier was completed. • The release rate of CEL increased on increasing the pore size of carriers. • The crystallinity

18. A poly(glycerol sebacate)-coated mesoporous bioactive glass scaffold with adjustable mechanical strength, degradation rate, controlled-release and cell behavior for bone tissue engineering.

Lin, Dan; Yang, Kai; Tang, Wei; Liu, Yutong; Yuan, Yuan; Liu, Changsheng

2015-07-01

Various requirements in the field of tissue engineering have motivated the development of three-dimensional scaffold with adjustable physicochemical properties and biological functions. A series of multiparameter-adjustable mesoporous bioactive glass (MBG) scaffolds with uncrosslinked poly(glycerol sebacate) (PGS) coating was prepared in this article. MBG scaffold was prepared by a modified F127/PU co-templating process and then PGS was coated by a simple adsorption and lyophilization process. Through controlling macropore parameters and PGS coating amount, the mechanical strength, degradation rate, controlled-release and cell behavior of the composite scaffold could be modulated in a wide range. PGS coating successfully endowed MBG scaffold with improved toughness and adjustable mechanical strength covering the bearing range of trabecular bone (2-12MPa). Multilevel degradation rate of the scaffold and controlled-release rate of protein from mesopore could be achieved, with little impact on the protein activity owing to an "ultralow-solvent" coating and "nano-cavity entrapment" immobilization method. In vitro studies indicated that PGS coating promoted cell attachment and proliferation in a dose-dependent manner, without affecting the osteogenic induction capacity of MBG substrate. These results first provide strong evidence that uncrosslinked PGS might also yield extraordinary achievements in traditional MBG scaffold. With the multiparameter adjustability, the composite MBG/PGS scaffolds would have a hopeful prospect in bone tissue engineering. The design considerations and coating method of this study can also be extended to other ceramic-based artificial scaffolds and are expected to provide new thoughts on development of future tissue engineering materials.

19. Vernonia cinerea Less. supplementation and strenuous exercise reduce smoking rate: relation to oxidative stress status and beta-endorphin release in active smokers

Yankai Araya

2010-05-01

Full Text Available Abstract Purpose The aim of this study was to evaluate the effects of Vernonia cinerea Less. (VC supplementation and exercise on oxidative stress biomarkers, beta-endorphin release, and the rate of cigarette smoking. Methods Volunteer smokers were randomly divided into four groups: group 1: VC supplement; group 2: exercise with VC supplement; group 3: exercise; and group 4: control. VC was prepared by wash and dry techniques and taken orally before smoking, matching the frequency of strenuous exercise (three times weekly. Before and after a two month period, exhaled carbon monoxide (CO, blood oxidative stress (malondialdehyde [MDA], nitric oxide [NOx], protein hydroperoxide [PrOOH] and total antioxidant capacity [TAC], beta-endorphin and smoking rate were measured, and statistically analyzed. Results In Group 1, MDA, PrOOH, and NOx significantly decreased, whereas TAC increased (p 0.05. In Group 3, MDA, PrOOH, NOx, TAC, and beta-endorphin levels increased significantly (p 0.05. All groups had lower levels of CO after the intervention. The smoking rate for light cigarette decreased in group 2(62.7%, 1(59.52%, 3 (53.57% and 4(14.04%, whereas in self-rolled cigarettes it decreased in group 1 (54.47%, 3 (42.30%, 2 (40% and 4 (9.2%. Conclusion Supplementation with Vernonia cinerea Less and exercise provided benefit related to reduced smoking rate, which may be related to oxidaive stress and beta-endorphine levels.

20. Evaluation of blood pressure and heart rate in patients with hypertension who received tapentadol extended release for chronic pain: a post hoc, pooled data analysis.

Biondi, David M; Xiang, Jim; Etropolski, Mila; Moskovitz, Bruce

2014-08-01

Hypertension is one of the most common co-existing conditions in patients with chronic pain, and the potential effects of an analgesic on heart rate and blood pressure are of particular concern for patients with hypertension. The purpose of this analysis was to evaluate changes in blood pressure and heart rate with tapentadol extended release (ER) treatment in patients with hypertension. We performed a post hoc analysis of data pooled from three randomized, placebo- and active-controlled, phase III studies of tapentadol ER for managing chronic osteoarthritis knee (NCT00421928, NCT00486811) or low back (NCT00449176) pain (15-week, double-blind treatment period). Data were independently analyzed for patients with a listed medical history of hypertension at baseline and patients with at least one listed concomitant antihypertensive medication at baseline. Heart rate, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured at each visit. In patients with a listed medical history of hypertension (n = 1,464), least-squares mean (LSM [standard error (SE)]) changes from baseline to endpoint with placebo, tapentadol ER, and oxycodone HCl controlled release (CR), respectively, were -0.7 (0.44), 0.2 (0.43), and -0.9 (0.45) beats per minute (bpm) for heart rate; -2.4 (0.64), -2.7 (0.64), and -3.7 (0.67) mmHg for SBP; and -1.0 (0.39), -1.3 (0.39), and -2.3 (0.41) mmHg for DBP; in patients with at least one listed concomitant antihypertensive medication (n = 1,376), the LSM (SE) changes from baseline to endpoint were -0.6 (0.45), 0.1 (0.44), and -0.7 (0.47) bpm for heart rate; -1.8 (0.66), -3.3 (0.65), and -3.7 (0.69) mmHg for SBP; and -0.7 (0.40), -1.4 (0.40), and -2.3 (0.42) mmHg for DBP. No clinically meaningful mean changes in heart rate or blood pressure were observed for the evaluated cohorts of patients with hypertension who were treated with tapentadol ER (100-250 mg twice daily).

1. Surface deformation associated with the 2013 Mw7.7 Balochistan earthquake: Geologic slip rates may significantly underestimate strain release

Gold, Ryan; Reitman, Nadine; Briggs, Richard; Barnhart, William; Hayes, Gavin

2015-04-01

sections with narrow deformation zones in order to capture the full deformation field. Our results imply that hazard analyses based on geologically-determined fault slip rates (e.g., near-field) should consider the significant and heterogeneous mismatch we document between on- and off-fault coseismic deformation.

2. Comparison of toxicity and release rates of Cu and Zn from anti-fouling paints leached in natural and artificial brackish seawater.

Ytreberg, Erik; Karlsson, Jenny; Eklund, Britta

2010-05-15

Biocide-containing anti-fouling paints are regulated and approved according to the added active ingredients, such as Cu. Biocide-free paints are considered to be less environmentally damaging and do not need an approval. Zn, a common ingredient in paints with the potential of causing adverse effects has received only minor attention. Laboratory experiments were conducted in artificial brackish seawater (ASW) and natural brackish seawater (NSW) to quantify release rates of Cu and Zn from biocide-containing and biocide-free labeled eroding anti-fouling paints used on commercial vessels as well as leisure boats. In addition, organisms from three trophic levels, the crustacean Nitocra spinipes, the macroalga Ceramium tenuicorne and the bacteria Vibrio fischeri, were exposed to Cu and Zn to determine the toxicity of these metals. The release rate of Cu in NSW was higher from the paints for professional use (3.2-3.6 microg cm(-)(2)d(-1)) than from the biocide leaching leisure boat paint (1.1 microg cm(-)(2)d(-1)). Biocide-free paints did leach considerably more Zn (4.4-8.2 microg cm(-)(2)d(-1)) than biocide-containing leisure boat paint (3.0 microg cm(-)(2)d(-1)) and ship paints (0.7-2.0 microg cm(-)(2)d(-1)). In ASW the release rates of both metals were notably higher than in NSW for most tested paints. The macroalga was the most sensitive species to both Cu (EC(50)=6.4 microg l(-1)) and Zn (EC(50)=25 microg l(-1)) compared to the crustacean (Cu, LC(50)=2000 microg l(-1) Zn, LC(50)=890 microg l(-1)), and the bacteria (Cu, EC(50)=800 microg l(-1) and Zn, EC(50)=2000 microg l(-1)). The results suggest that the amounts of Zn and Cu leached from anti-fouling paints may attain toxic concentrations in areas with high boat density. To fully account for potential ecological risk associated with anti-fouling paints, Zn as well as active ingredients should be considered in the regulatory process.

3. Remission Rate and Functional Outcomes During a 6-Month Treatment With Osmotic-Release Oral-System Methylphenidate in Children With Attention-Deficit/Hyperactivity Disorder.

Su, Yi; Li, Haibo; Chen, Yixin; Fang, Fang; Xu, Tong; Lu, Haiping; Xie, Ling; Zhuo, Jianmin; Qu, Jiazhi; Yang, Li; Wang, Yufeng

2015-10-01

Many definitions have been used to evaluate remission in patients with attention-deficit/hyperactivity disorder (ADHD) in different studies resulting with varied remission rates. This open-label, multicenter study investigated the remission rate in Chinese children (n = 239; aged 6-16 years) with a diagnosis of ADHD (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition), treated with osmotic-release oral-system methylphenidate at doses of 18, 36, and 54 mg, once daily. Two definitions of remission were used: (1) (primary end point): average scores of SNAP-IV (Swanson, Nolan, and Pelham, Fourth Edition) items of 1 or less (0-3 rating scale for each item) according to the subtype of ADHD (inattentive [1-9], hyperactive-impulsive [10-18], and combined type [1-18]), and (2) total score of SNAP-IV items 1 to 18 of 18 or less, at week 8. The study consisted of screening/baseline, titration/open-label treatment (8 weeks), and extended observation (up to 24 weeks) phases. Secondary efficacy assessments were Clinical Global Impression-Improvement (clinical efficacy), Behavior Rating Inventory of Executive Function Scale (BRIEF; executive function behaviors), and Weiss Functional Impairment Rating Scale (social function). Validity of remission was assessed by comparing the function measures (BRIEF and Weiss's) between patients who achieved remission and those who did not. At week 8, 69.3% (151/218) of patients achieved remission by definition 1, and 73.2% (161/220) by definition 2. At weeks 8 and 24, the remission group had significantly lower BRIEF, Weiss's, and Clinical Global Impression-Improvement scores (P methylphenidate was well tolerated, with increased remission rates in children with ADHD.

4. Does prolonged pituitary down-regulation with gonadotropin-releasing hormone agonist improve the live-birth rate in in vitro fertilization treatment?

Ren, Jianzhi; Sha, Aiguo; Han, Dongmei; Li, Ping; Geng, Jie; Ma, Chaihui

2014-07-01

To evaluate the effects of a prolonged duration of gonadotropin-releasing hormone agonist (GnRH-a) in pituitary down-regulation for controlled ovarian hyperstimulation (COH) on the live-birth rate in nonendometriotic women undergoing in vitro fertilization and embryo transfer (IVF-ET). Retrospective cohort study. University-affiliated hospital. Normogonadotropic women undergoing IVF. Three hundred seventy-eight patients receiving a prolonged pituitary down-regulation with GnRH-a before ovarian stimulation and 422 patients receiving a GnRH-a long protocol. Live-birth rate per fresh ET. In comparison with the long protocol, the prolonged down-regulation protocol required a higher total dose of gonadotropins. A lower serum luteinizing hormone (LH) level on the starting day of gonadotropin and the day of human chorionic gonadotropin (hCG) and a fewer number of oocytes and embryos were observed in the prolonged down-regulation protocol. However, the duration of stimulation and number of high-quality embryos were comparable between the two groups. A statistically significantly higher implantation rate (50.27% vs. 39.69%), clinical pregnancy rate (64.02% vs. 56.87%) and live-birth rate per fresh transfer cycle (55.56% vs. 45.73%) were observed in the prolonged protocol. Prolonged down-regulation in a GnRH-a protocol might increase the live-birth rates in normogonadotropic women. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

5. Calculation of the inventory and near-field release rates of radioactivity from neutron-activated metal parts discharged from the high flux isotope reactor and emplaced in solid waste storage area 6 at Oak Ridge National Laboratory

Kelmers, A.D.; Hightower, J.R.

1987-05-01

Emplacement of contaminated reactor components involves disposal in lined and unlined auger holes in soil above the water table. The radionuclide inventory of disposed components was calculated. Information on the composition and weight of the components, as well as reasonable assumptions for the neutron flux fueling use, the time of neutron exposure, and radioactive decay after discharge, were employed in the inventory calculation. Near-field release rates of /sup 152/Eu, /sup 154/Eu, and /sup 155/Eu from control plates and cylinders were calculated for 50 years after emplacement. Release rates of the europium isotopes were uncertain. Two release-rate-limiting models were considered and a range of reasonable values were assumed for the time-to-failure of the auger-hole linear and aluminum cladding and europium solubility in SWSA-6 groundwater. The bounding europium radionuclide near-field release rates peaked at about 1.3 Ci/year total for /sup 152,154,155/Eu in 1987 for the lower bound, and at about 420 Ci/year in 1992 for the upper bound. The near-field release rates of /sup 55/Fe, /sup 59/Ni, /sup 60/Co, and /sup 63/Ni from stainless steel and cobalt alloy components, as well as of /sup 10/Be, /sup 41/Ca, and /sup 55/Fe from beryllium reflectors, were calculated for the next 100 years, assuming bulk waste corrosion was the release-rate-limiting step. Under the most conservative assumptions for the reflectors, the current (1986) total radionuclide release rate was calculated to be about 1.2 x 10/sup -4/ Ci/year, decreasing by 1992 to a steady release of about 1.5 x 10/sup -5/ Ci/year due primarily to /sup 41/Ca. 50 refs., 13 figs., 8 tabs.

6. Technical note: Reduced pulsation chamber vacuum at normal pulsation rate and ratio provides adequate prestimulation to induce oxytocin release and milk ejection while simultaneous milk flow is prevented.

Neuheuser, Anna-Lena; Belo, Claire; Bruckmaier, Rupert M

2017-10-01

In the present study we investigated the milking characteristics and the oxytocin release in dairy cows milked after either manual prestimulation or a premilking period with pulsating liners at normal pulsation rate (60) and ratio (60:40) while the pulsation chamber vacuum (PCV) was reduced to 20 kPa to prevent the opening of the liners. During the milking trial with 8 cows the PCV reduction was started either before attachment (PCV-1) or immediately after attachment (PCV-2) of the teat cups. Milk yields, total milking times, average milk flows, peak flow rates, the duration of milk flow plateaus, and the duration of milk flow declines did not differ among the 3 treatments. Only the time to reach peak milk flow was prolonged when the vacuum reduction was started after teat cup attachment (PCV-2). In this treatment, milk flow >200 g/min already occurred during the premilking period, resulting in bimodal milk flow curves. In 5 of the 8 cows, plasma oxytocin (OT) concentrations were measured from -2 min before the start of milking until 3 min of milking to compare the OT release in response to manual prestimulation and during PCV-1. In both treatments, OT increased similarly and remained elevated until the end of measurements. Consequently, the areas under the curve of OT concentrations did not differ between treatments. In conclusion, milking performance is similar if milking is performed after manual prestimulation or after normal pulsation at reduced PCV. To prevent milk flow during the prestimulation period, it is of crucial importance to start the reduction of the PCV before cluster attachment. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

7. Evaluation of dual trigger with gonadotropin-releasing hormone agonist and human chorionic gonadotropin in improving oocyte maturity rates: A prospective randomized study

Nalini Mahajan

2016-01-01

Full Text Available BACKGROUND: Mature oocytes are prerequisite for achieving the process of in vitro fertilization. Human chorionic gonadotropin (hCG is the standard trigger used for stimulating ovulation but is associated with ovarian hyperstimulation syndrome (OHSS. Gonadotropin-releasing hormone agonist trigger achieves oocyte maturation and lowers the incidence of OHSS, but it has limitations of higher pregnancy loss rate and miscarriage rates. Coadministration of both hormones is found to improve the pregnancy rates and the number of mature oocytes retrieved. We aimed to assess if the dual trigger is better than the conventional hCG in triggering oocyte maturation. METHODOLOGY: The study included 76 female patients aged 24–43 years who were randomly divided into two groups with 38 patients in each arm. The study included patients with antimullerian hormone (AMH 4 ng/ml and AFC/ovary >12 to avoid OHSS risk with hCG trigger. RESULTS: The study showed statistically insignificant differences between dual group versus hCG group in terms of the number of oocytes retrieved (10.0 ± 5.6 vs. 8.7 ± 5.0; P = 0.2816, the number of mature oocytes recovered (8.4 ± 5.0 vs. 7.2 ± 4.0; P = 0.2588, fertilization rate (5.9 ± 4.2 vs. 5.6 ± 3.3; P = 0.7390, and the number of usable embryos on day 3 (4.0 ± 3.0 vs. 4.0 ± 2.4; P = 0.8991. CONCLUSION: The dual trigger is equivalent to hCG in triggering oocyte maturation.

8. Comparison of pregnancy rates in beef cattle after a fixed-time AI with once- or twice-used controlled internal drug release devices.

Muth-Spurlock, A M; Poole, D H; Whisnant, C S

2016-02-01

The use of fixed-time artificial insemination (FTAI) provides producers with numerous benefits including the use of superior genetics, shorter breeding and calving seasons, and a more uniform calf crop. However, the cost of implementing FTAI protocols is one of the several drawbacks hindering their use in the beef industry. Potential injection-site lesions from intramuscular injections of the hormones necessary for estrus synchronization are also a cause of concern for carcass quality. The objectives of this experiment were to (1) determine whether or not a twice-used controlled internal drug release (CIDR) device would be effective in an FTAI protocol without adversely affecting pregnancy rate and (2) whether or not the subcutaneous administration of PGF2α affects pregnancy rate. Nulliparous females (n = 99) between 13 and 27 months of age and multiparous cows (n = 43) between 48 and 74 months of age were synchronized for estrus using the 7-day CO-Synch + CIDR protocol. The females were randomly assigned to one of the two treatments: (1) a once-used CIDR (control) or (2) a twice-used CIDR device (treatment) incorporated into their synchronization protocol. The females were also randomly assigned to have their injection of PGF2α administered either intramuscularly or subcutaneously. Blood was taken in a random subset of nulliparous females (n = 52) just before device removal and assayed for concentration of progesterone. The concentration of progesterone was higher (P = 0.01) in the animals that received once-used CIDR devices than that in those received twice-used CIDR devices (3.4 ± 0.5 and 1.4 ± 0.5 ng/mL, respectively). There was no significant effect of parity (P = 0.82), artificial insemination technician (P = 0.60), PGF2α administration (P = 0.83), or treatment (P = 0.67) on pregnancy rates to artificial insemination which were 75.4 ± 6.0% and 71.7 ± 6.4%, for animals that received once- and twice-used CIDR devices, respectively. This study provides

9. Estimations of direct release rate of 137Cs and 90Sr to the ocean from the Fukushima Dai-ichi Nuclear Power Plant for five-and-a-half years

Tsumune, Daisuke; Aoyama, Michio; Tsubono, Takaki; Misumi, Kazuhiro; Tateda, Yutaka

2017-04-01

A series of accidents at the Fukushima Dai-ichi Nuclear Power Plant (1F NPP) following the earthquake and tsunami of 11 March 2011 resulted in the release of radioactive materials to the ocean by two major pathways, direct release from the accident site and atmospheric deposition. Additional release pathways by river input and runoff from 1F NPP site with precipitation and were also effective for coastal zone in the specific periods before starting direct release on March 26 2011. Direct release from 1F NPP site is dominant one year after the accident. We estimated the direct release rate of 137Cs and 90Sr for more than five-and-a-half years after the accident by the Regional Ocean Model System (ROMS). Direct release rate of 137Cs were estimated for five-and-a-half years after the accident by comparing simulated results and measured activities adjacent to the 1F NPP site(at 5,6 discharge and south discharge). Directly release rate of 137Cs was estimated to be the order of magnitude of 1014 Bq/day and decreased exponentially with time to be the order of magnitude of 109 Bq/day by the end of September 2016. Estimated direct release rate have exponentially reduced with constant rate since November 2011. Apparent half-life of direct release rate was estimated to be 346 days. The estimated total amounts of directly released 137Cs was 3.7±0.7 PBq for five and a half years. Simulated 137Cs activities attributable to direct release were in good agreement with observed activities, a result that implies the estimated direct release rate was reasonable. Simulated 137Cs activity affected off coast in the Fukushima prefecture. We used the measured 137Cs activities by the Tokyo Electric Power Company (TEPCO) for the estimation of direct release. The sea water samples were corrected from the coast. The averaged 137Cs activities from November 2013 to June 2016 were 391 and 383 Bq/m3 at 5,6 discharge and south discharge, respectively. The averaged 137Cs activities measured by the

10. Success rate, efficacy, and safety/tolerability of overnight switching from immediate- to extended-release pramipexole in advanced Parkinson's disease.

Schapira, A H V; Barone, P; Hauser, R A; Mizuno, Y; Rascol, O; Busse, M; Debieuvre, C; Fraessdorf, M; Poewe, W

2013-01-01

For Parkinson's disease (PD), an extended-release (ER) pramipexole formulation taken once daily, has shown efficacy, safety, and tolerability resembling those of immediate-release (IR) pramipexole taken three times daily. The present study assessed, in advanced PD, the success of an overnight switch from adjunctive IR to ER. Levodopa users experiencing motor fluctuations were randomized to adjunctive double-blind (DB) placebo, IR, or ER. Amongst completers of ≥18 weeks, ER recipients were kept on DB ER, whilst IR recipients were switched overnight to DB ER at unchanged daily dosage. After a DB week, switch success was assessed. During the next 5 weeks, all patients underwent ER titration to optimal open-label maintenance dosage. One week post-switch, 86.2% of 123 IR-to-ER and 83.8% of 105 ER-to-ER patients had ≤15% (or ≤3-point, for pre-switch scores ≤20) increase on UPDRS Parts II + III, and 77.9% (of 122) and 70.2% (of 104) had ≤1-h increase in daily OFF-time. At 32 weeks, the groups showed comparable improvements from DB baseline (pramipexole inception), including, on UPDRS II + III, adjusted mean (SE) changes of -14.8 (1.5) for IR-to-ER and -13.3 (1.6) for ER-to-ER. Rates of premature discontinuation owing to adverse events were 6.5% for IR-to-ER and 4.9% for ER-to-ER. By OFF-time and UPDRS criteria, majorities of patients with advanced PD were successfully switched overnight from pramipexole IR to ER at unchanged daily dosage. During subsequent maintenance, pramipexole showed sustained efficacy, safety, and tolerability, regardless of formulation (IR or ER) in the preceding DB trial. © 2012 The Author(s) European Journal of Neurology © 2012 EFNS.

11. Simultaneous parasympathetic and sympathetic activation reveals altered autonomic control of heart rate, vascular tension and epinephrine release in anaesthetized hypertensive rats

Torill eBerg

2011-11-01

Full Text Available Sympathetic hyperactivity and parasympathetic insufficiency characterize blood pressure control in genetic hypertension, but is difficult to demonstrate experimentally in anesthetized rats. Here we present a pharmacological approach to activate sympathetic and parasympathetic nerves simultaneously, and identify their contribution. Anaesthetized normotensive (WKY and spontaneously hypertensive rats (SHR were injected i.v. with 4-aminopyridine (4-AP, a voltage-sensitive K+ channel inhibitor. Blood pressure was recorded through a femoral artery catheter, cardiac output and heart rate (HR through an ascending aorta flow probe. Total peripheral vascular resistance (TPVR was calculated. 4-AP induced an immediate, atropine- and hexamethonium-sensitive bradycardia in WKY, and in strains, a subsequent, sustained tachycardia, and norepinephrine but not epinephrine release. The tachycardia was eliminated by reserpine, nadolol or right vagal nerve stimulation, but not adrenalectomy, scopolamine or hexamethonium. 4-AP-induced, atropine-sensitive bradycardia was observed in reserpinized or nadolol-treated SHR, where atropine also increased the late HR-response. 4-AP increased TPVR, transiently in WKY but sustained in SHR. Yohimbine but not phentolamine prevented TPVR down-regulation in WKY. Reserpine, phentolamine and prazosin eliminated the late vasoconstriction in SHR. Plasma epinephrine overflow increased in nadolol-treated SHR. Conclusions: 4-AP activated parasympathetic ganglion transmission and peripheral, sympathetic nerve norepinephrine release. The sympathetic component dominated the HR-response to 4-AP in SHR. α2-adrenceptor-dependent vasodilatation opposed norepinephrine-induced α1-adrenergic vasoconstriction in WKY, but not in SHR. A βAR-activated, probably vagal afferent mechanism, hampered adrenal epinephrine secretion in SHR. Thus, 4-AP exposed mechanisms, which contribute to hypertension, and may allow identification of the factors

12. Immediate versus delayed initiation of the levonorgestrel-releasing intrauterine system following medical termination of pregnancy - 1 year continuation rates: a randomised controlled trial.

Korjamo, R; Mentula, M; Heikinheimo, O

2017-06-26

To assess the 1-year continuation rates and new pregnancies following immediate versus delayed insertion of the levonorgestrel-releasing intrauterine system (LNG-IUS) after medical termination of pregnancy (MTOP) up to 20 weeks of gestation. A randomised controlled trial. Helsinki University Hospital, Finland, January 2013 to December 2014. A total of 267 women requesting MTOP and planning LNG-IUS for post-MTOP contraception. Insertion of LNG-IUS occurred immediately (0-3 days) or after a delay (2-4 weeks) following MTOP. Follow-up visits were at 3 months and 1 year after MTOP. LNG-IUS use at 1 year after MTOP. Women were randomised to immediate (n = 134) or delayed (n = 133) insertion of the LNG-IUS, and 133 and 131 were analysed; 127 (95.5%) women received immediate insertion and 111 (84.7%) women had delayed insertion of the LNG-IUS (risk ratio [RR] 1.13, 95% CI 1.04-1.22). The verified numbers of women continuing the LNG-IUS use at 1 year were 83 (62.4%) and 52 (39.7%) (RR 1.57, 95% CI 1.23-2.02). The numbers of new pregnancies were 6 (4.5%) and 16 (12.2%) (RR 0.37, 95% CI 0.15-0.91), and numbers of subsequent TOPs were 4 (3.0%) and 5 (3.8%) (RR 0.79, 95% CI 0.22-2.87). Immediate insertion of the LNG-IUS following MTOP resulted in higher 1-year continuation rates compared with delayed insertion. In addition, those receiving immediate insertion demonstrated a decreased new pregnancy rate, but no difference in the numbers of another TOP. Immediate LNG-IUS insertion after MTOP results in a higher 1-year continuation compared with delayed insertion. © 2017 Royal College of Obstetricians and Gynaecologists.

13. Exploitation of 3D face-centered cubic mesoporous silica as a carrier for a poorly water soluble drug: influence of pore size on release rate.

Zhu, Wenquan; Wan, Long; Zhang, Chen; Gao, Yikun; Zheng, Xin; Jiang, Tongying; Wang, Siling

2014-01-01

The purposes of the present work were to explore the potential application of 3D face-centered cubic mesoporous silica (FMS) with pore size of 16.0nm as a delivery system for poorly soluble drugs and investigate the effect of pore size on the dissolution rate. FMS with different pore sizes (16.0, 6.9 and 3.7nm) was successfully synthesized by using Pluronic block co-polymer F127 as a template and adjusting the reaction temperatures. Celecoxib (CEL), which is a BCS class II drug, was used as a model drug and loaded into FMS with different pore sizes by the solvent deposition method at a drug-silica ratio of 1:4. Characterization using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformation infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), nitrogen adsorption, X-ray diffraction (XRD), and differential scanning calorimetry (DSC) was used to systematically investigate the drug loading process. The results obtained showed that CEL was in a non-crystalline state after incorporation of CEL into the pores of FMS-15 with pore size of 16.0nm. In vitro dissolution was carried out to demonstrate the effects of FMS with different pore sizes on the release of CEL. The results obtained indicated that the dissolution rate of CEL from FMS-15 was significantly enhanced compared with pure CEL. This could be explained by supposing that CEL encountered less diffusion resistance and its crystallinity decreased due to the large pore size of 16.0nm and the nanopore channels of FMS-15. Moreover, drug loading and pore size both play an important role in enhancing the dissolution properties for the poorly water-soluble drugs. As the pore size between 3.7 and 16.0nm increased, the dissolution rate of CEL from FMS gradually increased.

14. Effect of release rate and enantiomeric composition on response to pheromones of Megaplatypus mutatus (Chapuis) in poplar plantations of Argentina and Italy.

Funes, Hernán; Zerba, Eduardo; Gonzalez-Audino, Paola

2013-10-01

Megaplatypus mutatus (=Platypus sulcatus Chapuis) is an Ambrosia beetle native to South America, which was recently introduced in Italy and its presence there is causing severe damage to the local poplar plantations. The male M. mutatus pheromone is composed of (S)-(+)-6-methyl-5-hepten-2-ol [(+)-sulcatol], 6-methyl-5-hepten-2-one (sulcatone) and 3-pentanol. A series of field trials testing dose, blend and enantiomer composition performed in Argentina and Italy evaluated attraction and found that the optimal release rate of pheromone components as baits in cross vane baited traps (CIPEIN-CV) was 6, 6 and 30 mg day−1 of sulcatone, (+)-sulcatol and 3-pentanol, respectively. It was also determined that racemic sulcatol is as effective as the pure (+)-isomer for the purpose of beetle catch, due to the inert nature of the (−)-isomer allowing the usage of low cost racemic sulcatol instead of highly expensive (+)-sulcatol. The results of our work contribute to the development of pheromone-based local technologies with low environmental impact and low cost for control or monitoring of an important pest.

15. Action of human group IIa secreted phospholipase A2 on cell membranes. Vesicle but not heparinoid binding determines rate of fatty acid release by exogenously added enzyme.

Koduri, R S; Baker, S F; Snitko, Y; Han, S K; Cho, W; Wilton, D C; Gelb, M H

1998-11-27

Human group IIa phospholipase A2 (hIIa-PLA2) is a highly basic protein that is secreted from a number of cells during inflammation and may play a role in arachidonate liberation and in destruction of invading bacteria. It has been proposed that rodent group IIa PLA2 is anchored to cell surfaces via attachment to heparan sulfate proteoglycan and that this interaction facilitates lipolysis. hIIa-PLA2 contains 13 lysines, 2 histidines, and 10 arginines that fall into 10 clusters. A panel of 26 hIIa-PLA2 mutants were prepared in which 1-4 basic residues in each cluster were changed to glutamate or aspartate (charge reversal). A detailed analysis of the affinities of these mutants for anionic vesicles and for heparin and heparan sulfate in vitro and of the specific activities of these proteins for hydrolysis of vesicles in vitro and of living cell membranes reveal the following trends: 1) the affinity of hIIa-PLA2 for heparin and heparan sulfate is modulated not by a highly localized site of basic residues but by diffuse sites that partially overlap with the interfacial binding site. In contrast, only those residues on the interfacial binding site of hIIa-PLA2 are involved in binding to membranes; 2) the relative ability of these mutants to hydrolyze cellular phospholipids when enzymes were added exogenously to CHO-K1, NIH-3T3, and RAW 264.7 cells correlates with their relative in vitro affinity for vesicles and not with their affinity for heparin and heparan sulfate. 3) The rates of exogenous hIIa-PLA2-catalyzed fatty acid release from wild type CHO-K1 cells and two mutant lines, one lacking glycosaminoglycan and one lacking heparan sulfate, were similar. Thus basic residues that modulate interfacial binding are important for plasma membrane fatty acid release by exogenously added hIIa-PLA2. Binding of hIIa-PLA2 to cell surface heparan sulfate does not modulate plasma membrane phospholipid hydrolysis by exogenously added hIIa-PLA2.

16. 丁二酮肟比色法测定包膜尿素释放养分速率%Determination of controlled release rate of membrane coated fertilizer by colorimetry with dimethylglyoxime

戴小敏; 刘袖洞; 左秀锦; 马小军

2013-01-01

以改性淀粉包膜尿素为模型,探讨用丁二酮肟比色法测定包膜尿素释放养分速率,以达到快速评价包膜尿素控制释放性能的目的.结果表明,丁二酮肟比色法测定包膜尿素释放养分速率可行,自制改性淀粉包膜尿素具有一定的控制释放性能.%Membrane coated Uurea was prepared with modified starch, and colorimetry with dimethylglyoxime was used to investigate the controlled release rate of urea. The purpose was to provide a fast analytical method to evaluate the controlled release property of membrane coated urea. The results showed that colorimetry with dimethylglyoxime was feasible to analyze release rate of urea.

17. 不同控释氮肥对玉米产量和氮肥利用率的影响%Effects of Different Controlled-release Nitrogen Fertilizer on Yield and Nitrogen Utilization Rate of Maize

袁嫚嫚; 叶舒娅; 刘枫; 李敏; 吴学忠

2011-01-01

[目的]为控释氮肥在玉米上的广泛应用提供理论依据.[方法]通过田间小区试验,比较了不同控释氮肥对玉米产量和氮肥利用率的影响.[结果]3种控释氮肥中树脂包膜氮肥增产和提高玉米氮肥利用率的效果均最好.相比普通氮肥,不同控释氮肥显著提高了玉米氮肥利用率,增幅达4.99～14.54个百分点.[结论]控释氮肥可以提高玉米氮肥利用率,树脂包膜氮肥在玉米上的应用效果最佳.%[ Objective] The aim was to provide a theoretical fouhdation for wide utilization of controlled-release nitrogen fertilizer in maize field.[ Method ] Field plot experiment was conducted to compare the different controlled-release nitrogen fertilizers on yield and nitrogen utilization rate of maize. [ Result] The highest yield and nitrogen utilization rate of maize was applied of controlled-release polyolefin-coated urea. Nitrogen utilization rate was increased signifieantly by 4.99％ to 14.54％ by the applying of controlled-release nitrogen fertilizer. [ Conclusion] Controlled-release nitrogen fertilizer could increase nitrogen utilization rate of maize significantly, controlled-release polyolefin-coated urea had a best effect on maize.

18. Experimental evaluation of gamma fluence-rate predictions from Argon-41 releases to the atmosphere over a nuclear research reactor site

Rojas-Palma, C.; Aage, H.K.; Astrup, P.

2004-01-01

An experimental study of radionuclide dispersion in the atmosphere has been conducted at the BR1 research reactor in Mol, Belgium. Artificially generated aerosols ('white smoke') were mixed with the routine releases of Ar-41 in the reactor's 60-m tall venting stack. The detailed plume geometry...

19. The Effect of Potassium Nitrate on the Reduction of Phytophthora Stem Rot Disease of Soybeans, the Growth Rate and Zoospore Release of Phytophthora Sojae

The effects of potassium nitrate (KNO3) application on Phytophthora stem rot disease reduction of Glycine max (L.) Merr. cvs. Chusei-Hikarikuro and Sachiyutaka, and fungal growth and zoospore release of a Phytophthora sojae isolate were investigated under laboratory conditions. The application of 4-...

20. Exploring the correlation between the sequence composition of the nucleotide binding G5 loop of the FeoB GTPase domain (NFeoB) and intrinsic rate of GDP release.

Guilfoyle, Amy P; Deshpande, Chandrika N; Schenk, Gerhard; Maher, Megan J; Jormakka, Mika

2014-12-12

GDP release from GTPases is usually extremely slow and is in general assisted by external factors, such as association with guanine exchange factors or membrane-embedded GPCRs (G protein-coupled receptors), which accelerate the release of GDP by several orders of magnitude. Intrinsic factors can also play a significant role; a single amino acid substitution in one of the guanine nucleotide recognition motifs, G5, results in a drastically altered GDP release rate, indicating that the sequence composition of this motif plays an important role in spontaneous GDP release. In the present study, we used the GTPase domain from EcNFeoB (Escherichia coli FeoB) as a model and applied biochemical and structural approaches to evaluate the role of all the individual residues in the G5 loop. Our study confirms that several of the residues in the G5 motif have an important role in the intrinsic affinity and release of GDP. In particular, a T151A mutant (third residue of the G5 loop) leads to a reduced nucleotide affinity and provokes a drastically accelerated dissociation of GDP.

1. 热熔压敏胶性能与药物释放速率的关系研究%Study on relationship of properties and drug release rate of hot melt pressure sensitive adhesive

俞振伟; 梁漪; 梁文权

2011-01-01

Objective: To investigate the relationship of properties and drug release rate of hot melt pressure sensitive adhesive ( HMPSA) , and to provide a recommendation of preparing and selecting of HMPSA for transdermal use. Method; HMPSA with different properties were prepared using styrene-isoprene-styrene triblock copolymer as main material, and the tacks, adhesions and cohesions were determined. Drug-in-adhesive type patches were prepared using α-asarone as model drug, and the drug release rates were investigated on single chamber diffusion cells using 60% ethanol solution as release media. Result; The prepared HMPSAs had different tacks, adhesions and cohesions. The drug release rates of HMPSA patches were related to the cohesions. The release rate decreased when the cohesion increased. Conclusion; The HMPSA with appropriate cohesion should be selected when preparing patches to balance the drug release rate and patch property.%目的:研究热熔压敏胶的性能与药物释放速率的关系,为经皮给药制剂用热熔压敏胶的制备与选择提供参考.方法:以苯乙烯-异戊二烯-苯乙烯三嵌段共聚物为主体材料制备了多种不同性能的热熔压敏胶,测定其初黏力、黏合力与内聚力；以α-细辛醚为模型药物制备各热熔压敏胶的胶黏分散型贴剂,以60％乙醇溶液为释放介质,于单室扩散池中测定药物的释放.结果:制备得到的热熔压敏胶具有不同的初黏力、黏合力与内聚力；热熔压敏胶贴剂的释放速率与热熔压敏胶的内聚力相关,内聚力越大,药物的释放速率就越慢.结论:制备贴剂时需选择内聚力适宜的热熔压敏胶,以达到药物释放速率和贴剂内聚力的平衡.

2. Finite-Layer Method: Exact Numerical and Analytical Calculations of the Energy Release Rate for Unidirectional Composite Specimens in Double-Cantilever Beam and End-Notched Flexure Tests

Timonin, A. M.

2016-09-01

Based on the finite-layer method, a method for evaluating the stress-strain state and energy release rate for specimens with delaminations in double-cantilever beam and end-notched flexure tests is proposed. Exact numerical solutions of boundary-value problems for the "stiff" systems of differential equations describing deformations of test specimens are obtained. The distributions of forces, moments, displacements, and rotations in the specimens and the distributions of normal and tangential stresses on their midline are presented. New closed-form expressions for these functions and for compliance of the specimens are developed. Calculation results for the energy release rate obtained by a numerical differentiation and from analytical relations are presented. Two new techniques for estimating the energy release rate are proposed: (1) using the calculated values of peak stress and jumps of displacements at the tip of delamination; (2) by evaluation of indeterminacy at the tip of delamination with the use of stresses and derivatives of stresses and displacements. The effect of the transverse shear and Poisson ratio on the results is estimated. A comparison of the numerical and analytical solutions obtained with known results and the ASTM standard is presented.

3. Effect of polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer on bioadhesion and release rate property of eplerenone pellets.

Kendre, Prakash Namdeo; Chaudhari, Pravin Digambar

2017-05-01

The present study involved the design and development of oral bioadhesive pellets of eplerenone. A solid dispersion of eplerenone was developed with a hydrophilic carrier, polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus(®)). Bioadhesive pellets were prepared from this solid dispersion using a combination of HPMC K4M and Carbopol 934P. Both the solid dispersion and the pellets were evaluated for various physicochemical properties such as solubility, entrapment efficiency, drug content, surface morphology, mucoadhesion and swelling behavior. Analysis carried out using FT-IR, DSC and XRD found no interaction between the eplerenone and excipients. The solid dispersion had irregular-shaped smooth-surfaced particles of diameter 265 ± 105.5 μm. In TEM analysis, eplerenone particles of size 79-120 nm were found. The solubility and dissolution of eplerenone in the Soluplus(®)-based solid dispersion were 5.26 and 2.50 times greater, respectively. Investigation of the swelling behavior of the pellets showed that the thickness of the gel layer increased continuously over the duration of the study. Moreover, a correlation was observed between the thickness and strength of the gel layer and the percentage release. The mechanism of drug release was found to be non-Fickian (anomalous), with the release kinetics approaching first-order kinetics. The bioavailability of the eplerenone bioadhesive pellet formulation was studied using Wistar rats and was found to be improved. An in vivo mucoadhesion study showed that the pellets are retained for 24 h in rabbits. It was concluded that Soluplus(®) had a positive effect on the solubility and dissolution of pellets without affecting the bioadhesion.

4. Matrix tablets: the effect of hydroxypropyl methylcellulose/anhydrous dibasic calcium phosphate ratio on the release rate of a water-soluble drug through the gastrointestinal tract I. In vitro tests.

Mamani, Pseidy L; Ruiz-Caro, Roberto; Veiga, María D

2012-12-01

Different hydroxypropyl methylcellulose (HPMC)/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed aiming to evaluate the influence of both components ratio in the control release of a water-soluble drug (theophylline). In order to characterise the matrix tablets, swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralised water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid). The HPMC/ADCP ratio has turned out to be the determinant in the matrix behaviour: the HPMC characteristic swelling behaviour was modulated, in some cases, by the ADCP characteristic acidic dissolution. When the HPMC/ADCP ratio was ≥0.69, buoyancy, continuous swelling and low theophylline dissolution rate from the matrices (H1, H2 and H3) were observed in all dissolution media. Consequently, these formulations could be adequate as gastro-retentive drug delivery systems. Additionally, HPMC/ADCP ratio ≤0.11 (H5 and H6) induces a pH-dependent drug release which could be applied to design control drug release enteric formulations (with a suitable enteric coating). Finally, a HPMC/ADCP ratio between 0.11 and 0.69 (H4) yield a gastrointestinal controlled drug release, due to its time-dependent buoyancy (7 h) and a total drug delivery in 17 h in simulated colonic fluid.

5. No Superiority of Treatment With Osmotic Controlled-Release Oral Delivery System-Methylphenidate Over Short/Medium-Acting Methylphenidate Preparations in the Rate and Timing of Injuries in Children With Attention-Deficit/Hyperactivity Disorder.

Golubchik, Pavel; Kodesh, Arad; Weizman, Abraham

Methylphenidate (MPH) treatment in patients with attention-deficit/hyperactivity disorder (ADHD) is reported to reduce the risk for injuries. In the present study, the rate and timing of injuries were compared among the various MPH preparations (4 and 6-8 vs 12 hour-acting) in children with ADHD. This real-world retrospective study covered the years 2011 to 2013. Participants included 2042 youngsters (aged 4-18 years, 13.01 ± 3.2 years; 71.8% males and 28.2% females) diagnosed with ADHD according to the International Statistical Classification of Diseases, 10th Revision criteria and treated with various MPH preparations. They were divided into 2 groups by their treatment preparation as follows: MPH-immediate release (MPH-IR)-4 hour-acting pooled with MPH-slow release/long-acting (MPH-SR/LA)- 6 to 8 hour-acting versus osmotic controlled-release oral delivery system-MPH (OROS-MPH; Concerta)-12 hour-acting that consisted of pooling of OROS-MPH only and OROS-MPH combined with the other MPH preparations. The monthly rates of injury, specifically, late injury (occurrence between 4:00 p.m. to midnight) and for multiple injuries, the time interval between injuries, were assessed. No significant differences in monthly rate of nonfatal injuries were found between OROS-MPH with or without 4/6 to 8 hour-acting MPH-formulations versus only 4/6 to 8 hour-acting MPH-preparations (P = 0.53). Neither were differences found in the between-injury time interval (P = 0.83) or in late-injury-rates (P = 0.37) between those groups. This real-world-naturalistic study in the community demonstrates that, in ADHD pediatric populations, OROS-MPH preparation is not superior to short/medium-acting (4/6-8 hours) MPH preparations regarding the rate and timing of injuries.

6. Differential effects of 18- and 24-Gy cranial irradiation on growth rate and growth hormone release in children with prolonged survival after acute lymphocytic leukemia

Cicognani, A.; Cacciari, E.; Vecchi, V.; Cau, M.; Balsamo, A.; Pirazzoli, P.; Tosi, M.T.; Rosito, P.; Paolucci, G.

1988-11-01

To evaluate the effects of two different doses of cranial irradiation on growth and growth hormone (GH) release, we studied 61 children with acute lymphocytic leukemia who had survived at least five years in continuous complete remission. Forty-three children received 24 Gy (group 1) and 18 children received 18 Gy (group 2). Height was evaluated at diagnosis, at the end of treatment, and 6, 12, and 24 months later. Growth hormone release was evaluated by arginine and levodopa tests after the end of treatment. After diagnosis, the height SD score decreased significantly in both groups; two years after the end of treatment, only group 1 showed an SD score for height that was still significantly lower than at diagnosis. Group 1 showed impaired GH responses to the tests and, compared with controls, group 1 in fact included a percentage of subjects with a normal response to levodopa (ie, greater than 8 micrograms/L) that was significantly lower (56.4% vs 83.3%) and a percentage of nonresponders to both tests that was significantly higher (21.6% vs 0%). These data indicate that only patients treated with lower cranial irradiation dosage (18 Gy) had complete growth recovery and normal GH responses to pharmacologic tests.

7. Dry powders based on PLGA nanoparticles for pulmonary delivery of antibiotics: modulation of encapsulation efficiency, release rate and lung deposition pattern by hydrophilic polymers.

Ungaro, Francesca; d'Angelo, Ivana; Coletta, Ciro; d'Emmanuele di Villa Bianca, Roberta; Sorrentino, Raffaella; Perfetto, Brunella; Tufano, Maria Antonietta; Miro, Agnese; La Rotonda, Maria Immacolata; Quaglia, Fabiana

2012-01-10

Although few experimental studies have been handled so far to exploit the potential of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) in the production of dry powders for antibiotic inhalation, there has been no comprehensive study on the role played by NP composition. In this work, we try to shed light on this aspect by designing and developing a pulmonary delivery system for antibiotics, such as tobramycin (Tb), based on PLGA NPs embedded in an inert microcarrier made of lactose, referred to as nano-embedded micro-particles (NEM). At nanosize level, helper hydrophilic polymers were used to impart the desired surface, bulk and release properties to PLGA NPs prepared by a modified emulsion-solvent diffusion technique. Results showed that poly(vinyl alcohol) (PVA) and chitosan (CS) are essential to optimise the size and modulate the surface properties of Tb-loaded PLGA NPs, whereas the use of alginate (Alg) allows efficient Tb entrapment within NPs and its release up to one month. Optimized formulations display good in vitro antimicrobial activity against P. aeruginosa planktonic cells. Furthermore, spray-drying of the NPs with lactose yielded NEM with peculiar but promising flow and aerosolization properties, while preserving the peculiar NP features. Nonetheless, in vivo biodistribution studies showed that PVA-modified Alg/PLGA NPs reached the deep lung, while CS-modified NPs were found in great amounts in the upper airways, lining lung epithelial surfaces. In conclusion, PLGA NP composition appears to play a crucial role in determining not only the technological features of NPs but, once processed in the form of NEM, also their in vitro/in vivo deposition pattern.

8. Dual trigger of oocyte maturation with gonadotropin-releasing hormone agonist and low-dose human chorionic gonadotropin to optimize live birth rates in high responders.

Griffin, Daniel; Benadiva, Claudio; Kummer, Nicole; Budinetz, Tara; Nulsen, John; Engmann, Lawrence

2012-06-01

To compare live birth rates after dual trigger of oocyte maturation with GnRH agonist (GnRHa) and low-dose hCG versus GnRHa alone in high responders with peak E(2) triggered with GnRHa alone or GnRHa plus 1,000 IU hCG (dual trigger) for oocyte maturation. GnRHa alone versus dual trigger. Live birth, implantation, and clinical pregnancy rates and OHSS. The dual-trigger group had a significantly higher live birth rate (52.9% vs. 30.9%), implantation rate (41.9% vs. 22.1%), and clinical pregnancy rate (58.8% vs. 36.8%) compared with the GnRHa trigger group. One case of mild OHSS occurred in the dual-trigger group, and there were no cases of OHSS in the GnRHa trigger group. Dual trigger of oocyte maturation with GnRHa and low-dose hCG in high responders with peak E(2) birth without increasing the risk of significant OHSS. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

9. Study on the Release Rate of Niacin in Different Media for the Compound Niacin Extended-release and Simvastatin Tablets%复方辛伐他汀烟酸缓释片中烟酸在不同释放介质中的释放度研究

王曙光; 王林; 邵振中; 陆小平; 杭夏清

2011-01-01

Objective To study the release rate of niacin for Niacin extended-release and Simvastatin tablets in different media, and analyze their release behavior in vitro. Methods The release of Niacin for self~prepared and imported compound preparation in four different media were determined by UV, the kinetics model and similarity factor(f2 value) were compared. Results Self-made and imported sustained-release tablets in vitro release of nicotinic acid were complied with the Ritger-Peppas equation, the n values of the equation in the four media were from 0.45 to 0.89, indicating that the drug release was caused by the interaction of the skeleton of drug diffusion and dissolution. Comparing with the value of the reference formulation, the f2 value of the self extended-release tablets which were in water, 0.lmol/L HC1, pH 4.5 acetate buffer and pH 6.8 phosphate buffer release medium were 67.59, 80.24, 67.27 and 65.57 respectively, which were greater than 50. Conclusion Niacin release behavior of self-prepared was consistent with the imported extended-release tablets in vitro.%目的 研究辛伐他汀烟酸缓释片在不同释放介质中烟酸的释放度,分析其在体外的释放行为.方法 用UV法 测定自制与进口辛伐他汀烟酸缓释片在四种不同介质中的烟酸释放情况,并对其释放模型和f2相似因子进行比较.结果 自制和进口缓释片的烟酸体外释放度符合Ritger-Peppas方程,在四种介质中方程拟合的n值均在0.45～0.89之间,说明该药物释放是药物扩散和骨架溶蚀共同作用的.与参比制剂相比,自制缓释片在水、0.1 mol/L盐酸、pH4.5醋酸盐缓冲液及pH 6.8磷酸盐缓冲液释放介质中,f2值分别为67.59、80.24、67.27和65.57,均大于50.结论 自制制剂与进口制剂的缓释部分体外释放行为相似.

10. Emission Rates of Volatile Organic Compounds Released from Newly Produced Household Furniture Products Using a Large-Scale Chamber Testing Method

Duy Xuan Ho

2011-01-01

Full Text Available The emission rates of volatile organic compounds (VOCs were measured to investigate the emission characteristics of five types of common furniture products using a 5 m3 size chamber at 25°C and 50% humidity. The results indicated that toluene and α-pinene are the most dominant components. The emission rates of individual components decreased constantly through time, approaching the equilibrium emission level. The relative ordering of their emission rates, if assessed in terms of total VOC (TVOC, can be arranged as follows: dining table > sofa > desk chair > bedside table > cabinet. If the emission rates of VOCs are examined between different chemical groups, they can also be arranged in the following order: aromatic (AR > terpenes (TER > carbonyl (CBN > others > paraffin (PR > olefin (HOL > halogenated paraffin (HPR. In addition, if emission strengths are compared between coated and uncoated furniture, there is no significant difference in terms of emission magnitude. Our results indicate that the emission characteristics of VOC are greatly distinguished between different furniture products in terms of relative dominance between different chemicals.

11. Analysis of initial chlorophyll fluorescence induction kinetics in chloroplasts in terms of rate constants of donor side quenching release and electron trapping in photosystem II

Vredenberg, W.J.

2008-01-01

The fluorescence induction F(t) of dark-adapted chloroplasts has been studied in multi-turnover 1 s light flashes (MTFs). A theoretical expression for the initial fluorescence rise is derived from a set of rate equations that describes the sequence of transfer steps associated with the reduction of

12. Energy storage and release of prosthetic feet. Part 2: subjective ratings of 2 energy storing and 2 conventional feet, user choice of foot and deciding factor

Postema, K.; Hermens, Hermanus J.; de Vries, J.; de Vries, J.; Koopman, Hubertus F.J.M.; Eisma, W.H.

1997-01-01

This paper is the second part of a study on biomechanical and functional properties of prosthetic feet. The first part dealt with a biomechanical analysis related to user benefits. This part deals with subjective ratings and deciding factors for trans-tibial amputees using 2 energy storing feet (ESF

13. Energy storage and release of prosthetic feet Part 2: Subjective ratings of 2 energy storing and 2 conventional feet, user choice of foot and deciding factor

Postema, K.; Hermens, H.J.; Vries, de J.; Koopman, H.F.J.M.; Eisma, W.H.

1997-01-01

This paper is the second part of a study on biomechanical and functional properties of prosthetic feet. The first part dealt with a biomechanical analysis related to user benefits. This part deals with subjective ratings and deciding factors for trans-tibial amputees using 2 energy storing feet (ESF

14. Effect of slow release-Fampridine on muscle strength, rate of force development, functional capacity and cognitive function in an enriched population of MS patients. A randomized, double blind, placebo controlled study

Jensen, H B; Nielsen, J L; Ravnborg, M.

2016-01-01

contraction (MVC) and rate of force development (RFD) of the lower extremities and 2) to replicate previously published data on the effect of slow release-Fampridine (SR-Fampridine) on the functional capacity of the lower limbs, the upper limb and cognitive function, in persons with multiple sclerosis (pw....... Furthermore, a significant effect of SR-Fampridine on T25FW, SSST and 5-STS was demonstrated. CONCLUSION: Gold standard dynamometry assessment of muscle strength showed improved MVC and RFD in persons with MS treated with SR-Fampridine compared to placebo. Furthermore, previous findings on the effects of SR...

15. 缓释尿素氮素利用率及肥效试验研究%Experimental Study on the Utilization Rate and Effect of Controlled-release Urea Nitrogen

邰日晶; 王晓茜

2014-01-01

The effect of five kinds of controlled release urea on maize and rice yield was studied adopting contrast test with common urea as the control. The experimental results show that slow release urea can increase the harvest of maize and rice, but the difference was not significant and the 5 slow release ureas can increase the corn fertilizer utilization rate, and the effect is better than that of rice.%为验证缓释尿素的肥料利用率和应用效果，采用对比试验的方法，以普通尿素作对照，研究5种缓释尿素对玉米和水稻产量的影响。试验结果表明，在等养分含量处理条件下，缓释尿素对玉米和水稻两种作物均具有增产作用，但差异不显著；5种缓释尿素都能不能程度地提高玉米的肥料利用率，且效果优于水稻。

16. Preparation of Osthol Microcapsules and Observation of its Release Rate in vitro%蛇床子素缓释微囊的制备及体外释药

郑立卿; 刘建华; 韩伟轩; 张丹参; 薛贵平

2011-01-01

目的:制备蛇床子素缓释微囊并考察其体外释放规律.方法:以明胶、阿拉伯胶为囊材,采用复凝聚法制备微囊,采用紫外分光光度法测含量,均匀设计优化制备工艺.分别以150 mL人工胃液与磷酸盐缓冲液(pH 6.8)为溶出介质,温度(37±0.5)℃,转速100 r·min-1,测定其体外释放度.结果:最佳制备工艺为囊心囊材质量比1∶1.5,温度60℃,戊二醛用量0.8∶120(戊二醛用量/系统体积),制备的微囊圆整光滑,粒径均匀,平均粒径(51.6±4)μm,包封率85.0%,载药量47.2%,体外缓释时间为6 h,其释药特征符合一级动力学过程.结论:蛇床子素微囊制备工艺简单,成囊性和重复性好,微囊具有明显的缓释效果.%Objective:To prepare osthol microcapsules and study its release rate in vitro. Method: Osthol microcapsules were prepared by complex coacervation using gelatin-acacia and uniform design. Osthol content was determined by UV. 150 mL artificial gastric and PBS (pH 6.8) were used as releasing media, the temperature was (37 ± 0.5) ℃ and the rate of rotation was 100 r· min-1. Result: The optimized conditions were: the ratio of osthol and coating material of 1: 1.5, temperature of 60 ℃ and a hardening agent of 0.8 per 120 of coacervation system.The microcapsules were round under sphere. The average microcapsules diameters were (51.6 ± 4) μm. And the content of osthol was 47.2％ with coating ratio of 85.0％. The microcapsules could be released for 6 h in vitro and its releasing curve fit first-order dynamic equations. Conclusion: The preparation method is simple and osthol microcapsules have obvious sustained-release effect.

17. The influence of hook type, angler experience, and fish size on injury rates and the duration of capture in an Alaskan catch-and-release rainbow trout fishery

Meka, J.M.

2004-01-01

Owing to concerns about the high incidence of past hooking injuries in Alagnak River rainbow trout Oncorhynchus mykiss, fish were captured with spin- and fly-fishing gear with barbed and barbless circle and "J" hooks to determine gear types contributing to injury. Landing and hook removal times were measured for a portion of fish captured, and the anatomical hooking location, hooking scar locations, bleeding intensity, angler experience, and fish size were recorded for all captured fish. Approximately 62% of fish captured experienced at least one new hooking injury, and 29% of fish had at least one past hooking injury. Small fish sustained higher new injury and bleeding rates, but large fish had higher past injury rates. Injury rates were higher for barbed J hooks, barbed J hooks took longer to remove, and fish caught by spin-fishing were injured more frequently than fish caught by fly-fishing. Fewer fly-fishing-caught fish were injured using circle hooks, and circle hooks tended to hook fish in only one location, generally in the jaw. Barbed J hooks were more efficient at landing fish, and J hooks were more efficient at landing fish than circle hooks. Novice anglers injured proportionally more fish than experienced anglers, primarily during hook removal. Landing time was positively correlated with fish size, and experienced anglers took longer to land fish than novices because they captured larger fish. These results suggest that a reduction in hooking injuries may be achieved by using circle hooks as an alternative to J hooks and barbless J hooks to reduce injury and handling time, yet catch efficiency for both methods would be reduced. Although fish captured with barbless J hooks and circle hooks had fewer injuries, it is important to note that each hook type also caused significant injury, and angler education is recommended to promote proper hook removal techniques.

18. 电针配合外侧支持带松解治疗髌骨软骨软化症的临床观察%Clinical Observation of Electric Acupuncture Combined with Lateral Retinacular Release in the Treatment of Chondromalacia Patellae

吴文虎; 郭纪涛

2009-01-01

目的:探讨电针配合外侧支持带松解治疗髌骨软骨软化症的临床疗效.方法:将60例患者随机分为治疗组和对照组.每组各30例,治疗组采用电针膝眼穴配合外侧支持带松解治疗;对照组采用电针膝眼穴治疗.根据HSS膝关节功能评分标准进行治疗前后及两组疗效的评价.结果:经治疗4周后,两组HSS评分均与治疗前相比差异有统计学意义(P<0.05),治疗组HSS评分与对照组比较差异有统计学意义(P<0.05).治疗组总有效率为96.7%,对照组总有效率为86.7%,两组疗效比较差异具有统计学意义(P<0.05).结论:电针配合外侧支持带松解治疗髌骨软骨软化症疗效确切,是一种安全有效的治疗方法.

19. Boar taint, meat quality and fail rate in entire male pigs and male pigs immunized against gonadotrophin releasing factor as related to body weight and feeding regime.

Moore, K L; Mullan, B P; Dunshea, F R

2017-03-01

The objective of this experiment was to compare the pork quality of entire male pigs and pigs immunized against GnRF (IC males) at both light (64.8kg) and heavy (106kg) liveweights and two feeding regimes (restricted at 2.5 times maintenance and ad libitum). There was no difference in objective measurements (P>0.05) or eating pork quality (P>0.1) between entire male and IC males. Fail rates were reduced by 9.1% and 12% for pork from IC males for quality grade (P=0.007) and re-purchase intention (P=0.001), respectively, compared to pork from entire males. Skatole (P=0.001) and androstenone (P<0.001) levels in belly fat were higher in entire male than IC male pigs. In addition, 37.5% of the light entire male pigs fed ad libitum showed skatole levels that exceeded the sensory threshold of 0.2μg/g. This work confirms that immunization against GnRF is effective in eliminating boar taint and reducing pork quality fail rates by approximately 10% compared to pork from entire males.

20. 4类昆虫信息化学物质在不同缓释载体上的释放速率%Researches on the Release Rates of Four Types of Insect Semiochemicals from Four Dispenser Types

李学琳; 孔祥波; 张苏芳; 王鸿斌; 张真; 杨茂发

2015-01-01

放量，然后释放速率逐渐下降到低释放状态。在释放高峰期，2种成分的释放速率只有第43天差异不显著，其余时间段均差异显著。【结论】明确了昆虫信息化学物质在4种常用缓释载体上的释放模式及其诱芯在林间的释放动态特征，对评价仿生诱芯在害虫种群监测和防控中的使用效果具有指导意义，可为生产上针对不同信息化学物质选用最适宜的缓释载体提供技术支持。%[Objective]In order to develop effective lures that can uniformly and persistently release biologically active semiochemicals in the field,it is necessary to determine the release rates of various insect pheromones and host volatiles from different types of commonly used dispensers after the active compounds are identified. [Method]In this study,the release rates of four common bark beetle aggregation pheromone components ( ipsenol,ipsdienol,trans-verbenol and S-cis-verbenol),two major Dendrolimus sex pheromone components (Z5,E7-12:Ald and Z5,E7-12:OH),and two conifer host volatiles ( S-( - )-α-pinene and R-( + )-α-pinene ) from four different types of dispensers were investigated under laboratory conditions ( temperature,24 -26 ℃; relative humidity,50%-80%; wind speed,300 mL·min -1 ) using dynamic headspace volatile collection method. The entrapped components on Porapak Q were extracted from sampling tubes with hexane and quantified by Gas Chromatography. [Results]Results indicated that ipsenol had higher release rates than ipsdienol from the polyvinylchloride bubble cap dispensers over the test period,showing significant differences for both ( +) and ( -) enantiomers of ipsenol and ipsdienol on day 2 ,22 ,and 29 . Ipsenol and ipsdienol released quickly in the first two days and gradually declined to the lower release level on day 15 ,then increased sharply during days 15 -36 with a peak of release rates at the day 36,but finally declined to a consistent low release level. The

1. 阿替洛尔缓释微囊载药量的测定及体外释放行为研究%Drug loading rate and in vitro release behavior of atenolol microcapsules

赛那; 顾艳丽; 张微; 李君; 金蓉

2012-01-01

目的 建立以乙基纤维素为囊材的阿替洛尔缓释微囊载药量测定方法,考察pH环境对微囊释药行为的影响.方法 采用HPLC法测定微囊的载药量,固定相为Grace Smart RPC18柱(250 mm×4.6 mm,5μm)；流动相为甲醇-pH 3.0磷酸盐缓冲液(30∶70)；流速为1 mL· min-1；检测波长为226 nm;柱温为25℃.分别以水、0.1 mol·L-1盐酸溶液、pH6.8的磷酸盐缓冲液为释放介质,采用桨法测定微囊累积释放度,应用SPSS 13.0软件对3种介质下含药微囊的释放行为进行单因素方差分析.结果 辅料对载药量的测定无影响,线性范围为8～64 μg·mL-1,r=0.999 8,平均回收率为100.2％,各项精密度符合要求.pH的变化对药物释放无影响.结论 建立的载药量测定方法良好,可用于载药量的测定.%Objective To establish a method to determine the drug-loading rate of atenolol sustained release microcapsules with ethyl cellulose as the capsule material. Dissolution behavior was studied in different pH values. Methods The drug-loading rate by HPLC. The column was Grace Smart RPC18 (250 mm × 4. 6 mm, 5 μm). The mobile phase was methanol-pH 3. 0 buffer phosphate (30 : 70). The flow rate was 1 mL · min-1. The detective wavelength was 226 nm. The column temperature was 25 ℃. Water, 0. 1 mol · L-1 hydrochloric acid solution and pH 3.0 buffer phosphate were respectively used as the release medium to study the cumulative release rate of microcapsules by the paddle method. Results The excipient had no effect on the determination of the medicine. The linear range was 8 -64 μg · mL-1 (r=0. 999 8). The average recovery was 100. 2%. The precision met the requirement. The release behavior under the 3 media was analyzed by oneway ANOVA. The variance of pH did not influence the drug release. Conclusion The method is feasible, which can be used for the determination of drug loading rate.

2. Nitrogen release during coal combustion

Baxter, L.L.; Mitchell, R.E.; Fletcher, T.H.; Hurt, R.H.

1995-02-01

Experiments in entrained flow reactors at combustion temperatures are performed to resolve the rank dependence of nitrogen release on an elemental basis for a suite of 15 U.S. coals ranging from lignite to low-volatile bituminous. Data were obtained as a function of particle conversion, with overall mass loss up to 99% on a dry, ash-free basis. Nitrogen release rates are presented relative to both carbon loss and overall mass loss. During devolatilization, fractional nitrogen release from low-rank coals is much slower than fractional mass release and noticeably slower than fractional carbon release. As coal rank increases, fractional nitrogen release rate relative to that of carbon and mass increases, with fractional nitrogen release rates exceeding fractional mass and fractional carbon release rates during devolatilization for high-rank (low-volatile bituminous) coals. At the onset of combustion, nitrogen release rates increase significantly. For all coals investigated, cumulative fractional nitrogen loss rates relative to those of mass and carbon passes through a maximum during the earliest stages of oxidation. The mechanism for generating this maximum is postulated to involve nascent thermal rupture of nitrogen-containing compounds and possible preferential oxidation of nitrogen sites. During later stages of oxidation, the cumulative fractional loss of nitrogen approaches that of carbon for all coals. Changes in the relative release rates of nitrogen compared to those of both overall mass and carbon during all stages of combustion are attributed to a combination of the chemical structure of coals, temperature histories during combustion, and char chemistry.

3. Controlled-release microchips.

Sharma, Sadhana; Nijdam, A Jasper; Sinha, Piyush M; Walczak, Robbie J; Liu, Xuewu; Cheng, Mark M-C; Ferrari, Mauro

2006-05-01

Efficient drug delivery remains an important challenge in medicine: continuous release of therapeutic agents over extended time periods in accordance with a predetermined temporal profile; local delivery at a constant rate to the tumour microenvironment to overcome much of the systemic toxicity and to improve antitumour efficacy; improved ease of administration, and increasing patient compliance required are some of the unmet needs of the present drug delivery technology. Microfabrication technology has enabled the development of novel controlled-release microchips with capabilities not present in the current treatment modalities. In this review, the current status and future prospects of different types of controlled-release microchips are summarised and analysed with reference to microneedle-based microchips, as well as providing an in-depth focus on microreservoir-based and nanoporous microchips.

4. Cortisol release, heart rate and heart rate variability, and superficial body temperature, in horses lunged either with hyperflexion of the neck or with an extended head and neck position.

Becker-Birck, M; Schmidt, A; Wulf, M; Aurich, J; von der Wense, A; Möstl, E; Berz, R; Aurich, C

2013-04-01

Bringing the head and neck of ridden horses into a position of hyperflexion is widely used in equestrian sports. In our study, the hypothesis was tested that hyperflexion is an acute stressor for horses. Salivary cortisol concentrations, heart rate, heart rate variability (HRV) and superficial body temperature were determined in horses (n = 16) lunged on two subsequent days. The head and neck of the horse was fixed with side reins in a position allowing forward extension on day A and fixed in hyperflexion on day B. The order of treatments alternated between horses. In response to lunging, cortisol concentration increased (day A from 0.73 ± 0.06 to 1.41 ± 0.13 ng/ml, p stress response to hyperflexion of the head alone in horses lunged at moderate speed and not touched with the whip. However, if hyperflexion is combined with active intervention of a rider, a stressful experience for the horse cannot be excluded.

5. Renin release

Schweda, Frank; Friis, Ulla; Wagner, Charlotte;

2007-01-01

The aspartyl-protease renin is the key regulator of the renin-angiotensin-aldosterone system, which is critically involved in salt, volume, and blood pressure homeostasis of the body. Renin is mainly produced and released into circulation by the so-called juxtaglomerular epithelioid cells, located......, salt, and volume overload. In contrast, the events controlling the function of renin-secreting cells at the organ and cellular level are markedly less clear and remain mysterious in certain aspects. The unravelling of these mysteries has led to new and interesting insights into the process of renin...

6. 檫树、米槠、木荷板材燃烧热释放率研究%Study on Burning Heat Release Rate of Sassafras tzumu, Castanopsis Carlesii, Schima Superba Lumber

黄晓东; 刘雁; 刘武

2001-01-01

In order to select qualified fire retardant lumber, the burning heat release rate of Sassafras tzu mu, Castanopsis Carlesii and Schima Superba lumber was measured with HRR3 system produced by AT LAS company, and the fire-retardancy of lumber of the species was appraised according to Airworthiness Approval Tag US Department of Transportation Federal Aviation Administation.%采用美国阿特拉斯公司生产的HRR3热释放率系统，按照美国航空局(FAA)的标准要求测试檫树、米槠、木荷板材燃烧的热释放率(HRR)，为阻燃板材选择合格基材。

7. Experiments on decomposition rate and release forms of nitrogen and phosphorus from the decomposing cyanobacterial detritus%蓝藻碎屑分解速率及氮磷释放形态的实验分析

李柯; 关保华; 刘正文

2011-01-01

The decomposition rate of cyanobacterial detritus and the release forms of nitrogen and phosphorus from the decomposing cyanobacterial detritus were investigated experimentally in this paper. Results showed that the content of total nitrogen of cyanobacterial detritus was 88.56 ±4. 10 mg/g; the decomposition rate of cyanobacterial detritus was high and there was 41.9% dry mass lost in two days. The release rate of total phosphorus of cyanobacterial detritus was faster than total nitrogen, but the increase in concentration of total dissolved nitrogen (TON) in the water column lasted longer than total dissolved phosphorus (TDP) during the decomposing of cyanobacteria. After the increase in the first four days, the concentration of dissolved inorganic nitrogen (DIN) was kept constant but the concentration of dissolved organic nitrogen ( DON) continued to increase. The ammonia was the main form of DIN in the water column, while the concentration of nitrate and nitrite was low during the decomposition. The Urea-N was not the main form of DON released by cyanobacterial detritus because the average percentage of Urea-N was low (3% of DON). The concentration of dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus ( DOP) increased in the first four days, and then DOP was transformed into DIP progressively. The present study demonstrated that the decomposition rate of cyanobacterial detritus is high, with releasing of organic and inorganic nitrogen and phosphorus. The result of present study shed light on understanding of the impact of cyanobacterial blooms on nitrogen and phosphorus cycling of lakes.%在试验条件下研究了水华蓝藻堆积使叶绿素浓度达到1600μg/L时,水体所含蓝藻形成的碎眉在水中的分解速率及其营养盐释放情况.结果表明:蓝藻碎屑的总氮含量为88.56±4.10mg/g,其在水体中有较高的分解速率,2d内即分解掉41.9％的生物量;蓝藻碎屑磷释放速率要高于氮,但其导致的水

8. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis.

Mortazavi, Gh; Haghani, M; Rastegarian, N; Zarei, S; Mortazavi, S M J

2016-03-01

According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring.

9. Increased Release of Mercury from Dental Amalgam Fillings due to Maternal Exposure to Electromagnetic Fields as a Possible Mechanism for the High Rates of Autism in the Offspring: Introducing a Hypothesis

Mortazavi, Gh.; Haghani, M.; Rastegarian, N.; Zarei, S.; Mortazavi, S.M.J.

2016-01-01

According to the World Health Organization (WHO), factors such as growing electricity demand, ever-advancing technologies and changes in social behaviour have led to steadily increasing exposure to man-made electromagnetic fields.  Dental amalgam fillings are among the major sources of exposure to elemental mercury vapour in the general population. Although it was previously believed that low levels are mercury (i.g. release of mercury from dental amalgam) is not hazardous, now numerous data indicate that even very low doses of mercury cause toxicity. There are some evidence indicating that perinatal exposure to mercury is significantly associated with an increased risk of developmental disorders such as autism spectrum disorders (ASD) and attention-deficit hyperactivity disorder (ADHD). Furthermore, mercury can decrease the levels of neurotransmitters dopamine, serotonin, noreprenephrine, and acetylcholine in the brain and cause neurological problems. On the other hand, a strong positive correlation between maternal and cord blood mercury levels is found in some studies. We have previously shown that exposure to MRI or microwave radiation emitted by common mobile phones can lead to increased release of mercury from dental amalgam fillings. Moreover, when we investigated the effects of MRI machines with stronger magnetic fields, our previous findings were confirmed. As a strong association between exposure to electromagnetic fields and mercury level has been found in our previous studies, our findings can lead us to this conclusion that maternal exposure to electromagnetic fields in mothers with dental amalgam fillings may cause elevated levels of mercury and trigger the increase in autism rates. Further studies are needed to have a better understanding of the possible role of the increased mercury level after exposure to electromagnetic fields and the rate of autism spectrum disorders in the offspring. PMID:27026954

10. Taxas de decomposição e de liberação de macronutrientes da palhada de aveia preta em plantio direto Decomposition rate and nutrient release of oat straw used as mulching in no-till system

Carlos Alexandre Costa Crusciol

2008-01-01

Full Text Available A palhada das plantas de cobertura mantida sobre o solo em plantio direto é uma reserva importante de nutrientes a ser liberada para as culturas subseqüentes, principalmente em regiões de clima tropical, devido às altas taxas de decomposição dos resíduos. O trabalho foi desenvolvido em condições de campo, durante 1998, no Município de Marechal Cândido Rondon, na Região Oeste do Estado do Paraná. O objetivo deste trabalho foi avaliar a taxa de decomposição e a velocidade de liberação de macronutrientes da palhada de aveia preta, na Região Oeste do Estado do Paraná. O delineamento experimental foi em blocos casualizados, com quatro repetições. As plantas foram manejadas aos trinta dias após a emergência. A persistência de palhada e a liberação de nutrientes do resíduo de aveia preta foram avaliadas 0, 13, 35 e 53 dias após a rolagem e dessecação. A taxa de decomposição da aveia foi constante (restando 34% do teor inicial e inversamente proporcional à relação C/N com valor inicial de 34 e final de 50. A maior parte do K é liberada logo após o manejo da aveia preta, restando na última coleta apenas 2% do teor inicial. N, P, Ca e S são liberados de forma gradual, restando na última avaliação, respectivamente, 55%, 42%, 48% e 47% da quantidade acumulada. O K seguido do N são os nutrientes disponibilizados em maior quantidade no solo, atingindo máxima velocidade de liberação entre 10 e 20 dias após o manejo da fitomassa de aveia preta.Plant residues left on soil surface in no-tillage systems are an important source of nutrients for the following crops, particularly under tropical climate, in which high residue decomposition rates shorten their persistence. The objective of this research work was to evaluate black oat decomposition and release of nutrients. The experiment was carried out during the 1998 cropping season in an experimental area located in Marechal Cândido Rondon, Paraná State, Brazil. A

11. Content Determination and Release Rate in Metformin Hydrochloride Sustained-release Tablets by HPLC%高效液相色谱法测定盐酸二甲双胍缓释片中盐酸二甲双胍的含量和释放度

宋新康; 曾玉梅

2016-01-01

目的：建立测定盐酸二甲双胍缓释片中盐酸二甲双胍含量和释放度的方法。方法：采用C18色谱柱（150 mm ×4．6 mm，5μm）；流动相：0．05％庚烷磺酸钠溶液（用10％磷酸溶液调节pH至4．0）－乙腈（ V∶V＝84∶16），流速：0．8 ml／min；检测波长：233 nm；柱温：35℃。结果：盐酸二甲双胍在2．45～98．00μg／ml（r＝1，n＝6）呈良好的线性关系，回收率99．2％，RSD为0．84％。结论：该方法适用于盐酸二甲双胍缓释片的质量控制。%OBJECTIVE: To establish a method of content determination and release rate in Metformin hydrochloride sustained-release tablets by HPLC .METHODS: C18 chromatographic column ( 150 mm ×4.6 mm, 5 μm) was adopted , the mobile phase was 0.05% heptane sodium sulfonate solution ( with 10% phosphoric acid solution to adjust pH value to 4.0 ) -acetonitrile ( V∶V =84∶16 ) , with flow rate of 0.8 ml/min.The detection wavelength was 233 nm and the column temperature was 35 ℃.RESULTS:Metformin hydrochloride had good linear relationship in 2.45-98.00 μg/ml ( r=1 , n=6 ) , The recovery rate was 99.2% and RSD was 0.84%. CONCLUSIONS:The method is suitable for Metformin hydrochloride sustained-release tablets quality control .

12. Dual trigger with combination of gonadotropin-releasing hormone agonist and human chorionic gonadotropin significantly improves the live-birth rate for normal responders in GnRH-antagonist cycles.

Lin, Ming-Huei; Wu, Frank Shao-Ying; Lee, Robert Kuo-Kuang; Li, Sheng-Hsiang; Lin, Shyr-Yeu; Hwu, Yuh-Ming

2013-11-01

To investigate whether dual triggering of final oocyte maturation with a combination of gonadotropin-releasing hormone (GnRH) agonist and human chorionic gonadotropin (hCG) can improve the live-birth rate for normal responders in GnRH-antagonist in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI) cycles. Retrospective cohort study. Infertility unit of a university-affiliated medical center. Normal responders to controlled ovarian hyperstimulation who were undergoing IVF-ICSI with a GnRH antagonist protocol. Standard dosage of hCG trigger (6,500 IU of recombinant hCG) versus dual trigger (0.2 mg of triptorelin and 6,500 IU of recombinant hCG). Live-birth, clinical pregnancy, and implantation rates per cycle. A total of 376 patients with 378 completed cycles with embryo transfer were enrolled (hCG trigger/control group: n = 187; dual trigger/study group: n = 191). The dual trigger group demonstrated statistically significantly higher implantation (29.6% vs. 18.4%), clinical pregnancy (50.7% vs. 40.1%), and live-birth (41.3% vs. 30.4%) rates as compared with the hCG trigger group. There was no statistically significant difference in terms of patient demographics, cycle parameters, or embryo quality. Dual trigger of final oocyte maturation with a GnRH-agonist and a standard dosage of hCG in normal responders statistically significantly improves implantation, clinical pregnancy, and live-birth rates in GnRH-antagonist IVF cycles. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

13. News release

2005-01-01

A few days ago. the State Bureau of Quality Inspection declared the sample result of ceramic tiles and sanitarywares. 47 out of 62 types of ceramic tiles sampled are qualified. the qualified rate of which is 75.8%. Six types of ceramic tiles are exposed for exceeding the standard of radiation, 58 out of 87 types of sanitarywares are qualified, the qualified rate of which is 66.7%. Eight types of sanitarywares are exposed for the lack of foul smells prevention function.

14. Rate of tuberculosis infection in children and adolescents with household contact with adults with active pulmonary tuberculosis as assessed by tuberculin skin test and interferon-gamma release assays.

Ferrarini, M A G; Spina, F G; Weckx, L Y; Lederman, H M; De Moraes-Pinto, M I

2016-03-01

Tuberculosis (TB) infection was evaluated in Brazilian immunocompetent children and adolescents exposed and unexposed (control group) to adults with active pulmonary TB. Both groups were analysed by clinical and radiological assessment, TST, QFT-IT and T-SPOT.TB. The three tests were repeated after 8 weeks in the TB-exposed group if results were initially negative. Individuals with latent tuberculosis infection (LTBI) were treated and tests were repeated after treatment. Fifty-nine TB-exposed and 42 controls were evaluated. Rate of infection was 69·5% and 9·5% for the exposed and control groups, respectively. The exposed group infection rate was 61% assessed by TST, 57·6% by T-SPOT.TB, and 59·3%, by QFT-IT. No active TB was diagnosed. Agreement between the three tests was 83·1% and 92·8% in the exposed and control groups, respectively. In the exposed group, T-SPOT.TB added four TB diagnoses [16%, 95% confidence interval (CI) 1·6-30·4] and QFT-IT added three TB diagnoses (12%, 95% CI 0-24·7) in 25 individuals with negative tuberculin skin test (TST). Risk factors associated to TB infection were contact with an adult with active TB [0-60 days: odds ratio (OR) 6·9; >60 days: OR 27·0] and sleeping in the same room as an adult with active TB (OR 5·2). In Brazilian immunocompetent children and adolescents, TST had a similar performance to interferon-gamma release assays and detected a high rate of LTBI.

15. Dose-rate conversion factors for external exposure to photon and electron radiation from radionuclides occurring in routine releases from nuclear fuel cycle facilities. [Conversion factors are given for dose rates to 21 organs from 240 different radionuclides for 3 different modes of exposure

Kocher, D.C.

1979-02-01

Dose-rate conversion factors for external exposure to photon and electron radiation have been calculated for 240 radionuclides of potential importance in routine releases from nuclear fuel cycle facilities. Dose-rate conversion factors for immersion in contaminated air, immersion in contaminated water, and exposure to a contaminated ground surface are estimated for tissue-equivalent material at the body surface of an exposed individual. For each exposure mode, photon dose-rate conversion factors are also estimated for 22 body organs. The calculations assume that the contaminated air, water, and ground surface are infinite in extent and that the radionuclide concentration is uniform. Dose-rate conversion factors for immersion in contaminated air and water are based on the requirement that all energy emitted in the decay of a radionuclide is absorbed in the infinite medium. Dose-rate conversion factors for ground-surface exposure are calculated for a height of 1 m using the point-kernel integration method and known specific absorbed fractions for photons and electrons in air. The computer code DOSFACTER written to perform the calculations is described and documented.

16. Study on Decomposition Rate and Nutrition Release of Submerged Macrophytes（Vallisneria spiralis） in Winter%冬季苦草分解速率及营养盐释放规律研究

陈见; 谢从新; 何绪刚; 胡雄; 李佩; 陆诗敏

2011-01-01

采用分解网袋法研究了冬季苦草腐败分解速率及其氮、磷损失规律。结果表明：苦草腐败释放的磷大部分被底泥吸附,少量进入水体;释放到水体中的氨氮（NH4＋-N）、亚硝态氮（NO2--N）和硝态氮（NO3--N）数量也较少;底泥减缓了苦草干重损失速度,而加快了TN和TP损失速率;苦草分解过程中磷的释放速率比氮快;苦草腐败分解具有阶段性,前36d分解迅速,以后分解速率显著下降。%This paper studied on the rate of decomposition of tape grass（Vallisneria spiralis） as well as the law of the release of nitrogen and phosphorus in the decomposed tape grass in winter using a litter-bag method.The results showed the majority of phosphorus

17. News/Press Releases

Office of Personnel Management — A press release, news release, media release, press statement is written communication directed at members of the news media for the purpose of announcing programs...

18. 以社区矫正降低青年刑满释放人员再犯罪率初探%Primary Research on the Community Correction to Reduce Crime Rate of Youth Personnel Released after Serving His Sentence

李杰

2011-01-01

刑满释放人员一直是我国社会需要：关注的群体，因为这些人员长时间脱离社会而无法跟上社会发展的脚步，并由此导致了一些人走上重新犯罪的道路。社区矫正作为一种监外刑罚执行方法可以避免犯罪人员与社会的脱节，不无遗憾的是社区矫正的实施存在许多不足，我们旨在以对社区矫正试点的实施情况为立足点，提出完善社区矫正制度的方向，同时通过对青年再犯罪特点的分析，提出降低青年再犯罪率的措施。%The personnel released after serving his sentence has been the groups needed to concern in our society. Because of long time away from society they couldn＇t keep up with the steps of social development, and this has resulted in some of them to go to the road of crime again. Community correction as a kind of penalty execution method outside of prison can prevent criminals and social disconnection. But the implementation of community correction has many shortcomings. This paper puts forward to perfect the system of community correction direction, and the measures to reduce youth crime rate.

19. Drug release from non-aqueous suspensions. II. The release of methylxanthines from paraffin suspensions

Blaey, C.J. de; Fokkens, J.G.

1984-01-01

The release of 3 methylxanthines, i.e. caffeine, theobromine and theophylline, from suspensions in liquid paraffin to an aqueous phase was determined in an in vitro apparatus. The release rates were determined as a function of the pH of the aqueous phase. It was proved that the release process was n

20. Flouride release from various restorative materials.

Bala, O; Uçtaşli, M; Can, H; Türköz, E; Can, M

1997-09-01

Fluoride release from six light-activated restorative materials, including two resinmodified glass-ionomers, two composites, and two compomers, was evaluated and compared with one conventional acid-based glass-ionomer cement. The amount and rate of release varied among the tested materials. Both resin-modified glass-ionomers and the conventional acid-base glass-ionomer cements released more fluoride then the composites and compomers (p < 0.05). Additionally, composite materials released less fluoride than compomer materials (p < 0.05). Release of fluoride by the tested materials showed a significant decrease after all the tested time intervals.

1. Modelling and analysis of impulsive releases of sterile mosquitoes.

Huang, Mingzhan; Song, Xinyu; Li, Jia

2017-12-01

To study the impact of releasing sterile mosquitoes on mosquito-borne disease transmissions, we propose two mathematical models with impulsive releases of sterile mosquitoes. We consider periodic impulsive releases in the first model and obtain the existence, uniqueness, and globally stability of a wild-mosquito-eradication periodic solution. We also establish thresholds for the control of the wild mosquito population by selecting the release rate and the release period. In the second model, the impulsive releases are determined by the closely monitored wild mosquito density, or the state feedback. We prove the existence of an order one periodic solution and find a relatively small attraction region, which ensures the wild mosquito population is under control. We provide numerical analysis which shows that a smaller release rate and more frequent releases are more efficient in controlling the wild mosquito population for the periodic releases, but an early release of sterile mosquitoes is more effective for the state feedback releases.

2. Fluoride release from newly marketed fluoride varnishes.

Jablonowski, Beth L; Bartoloni, Joseph A; Hensley, Donna M; Vandewalle, Kraig S

2012-03-01

New fluoride varnishes have been marketed that reportedly release more fluoride (Enamel Pro) or release fluoride more slowly (Vanish XT). The purpose of this study was to compare the amount and rate of fluoride release of new fluoride varnishes with other traditional fluoride varnishes. Extracted molars were cut into block sections. The enamel surfaces of the sections were painted with Enamel Pro, Duraphat, Vanish, or Vanish XT fluoride varnishes. One group was not treated and served as a negative control. The tooth sections were immersed in artificial saliva. The concentration of fluoride in parts per million was measured after the first 30 minutes, daily for the first week, and weekly until the level was below the limit of detection. Fluoride release was plotted over time. Cumulative fluoride release and rate of release (slope) were analyzed using one-way ANOVA/Tukey (α = .05). Enamel Pro had the greatest cumulative fluoride release. There was no significant difference between Duraphat and Vanish. Vanish XT had the lowest cumulative fluoride release. The rate of fluoride release from 1 week to limit of detection was Enamel Pro > Vanish > Duraphat > Vanish XT. The two newly marketed fluoride varnishes (Enamel Pro and Vanish XT) had significantly different fluoride release from the two conventional fluoride varnishes (Duraphat and Vanish).

3. Pregnancy rates after fixed-time artificial insemination of Brahman heifers treated to synchronize ovulation with low-dose intravaginal progesterone releasing devices, with or without eCG.

Butler, S A A; Atkinson, P C; Boe-Hansen, G B; Burns, B M; Dawson, K; Bo, G A; McGowan, M R

2011-11-01

The objective was to determine whether eCG in an ovulation synchronization protocol with an intravaginal progesterone (P(4))-releasing device (IPRD) containing a low dose of P(4) improves pregnancy rate (PR) to fixed-time AI (FTAI) in Bos indicus heifers. Day 0, 2 y old Brahman heifers were allocated to either eCG+ (n = 159) or eCG- (n = 157) treatment groups. All heifers were weighed, body condition scored (BCS), and ultrasonographically examined to measure uterine horn diameter and presence of a CL. On Day 0, all heifers received a low-dose IPRD (0.78 g P(4)) and 1 mg of estradiol benzoate (EB) im. On Day 8, the IPRD was removed, all heifers received 500 μg cloprostenol im, and those in the eCG+ treatment group received 300 IU of eCG im. On Day 9, all heifers received 1 mg EB im. All heifers were FTAI 52 to 56 h after IPRD removal. Ten days after FTAI, heifers were exposed to bulls. Heifers were diagnosed as pregnant to FTAI, natural mating, or not detectably pregnant (NDP) 65 d after FTAI. Treatment with eCG+ as compared to eCG- did not affect PR to FTAI (28.9 vs 30.6%; P = 0.590), natural mating (51.3 vs 47.7%; P = 0.595), or overall (65.4 vs 63.7%; P = 0.872). Mean live weight gain from Days 0 to 65 d post-FTAI was higher in heifers pregnant to FTAI (72.29 ± 4.26 kg; P = 0.033) and overall (66.83 ± 3.65 kg; P = 0.021), compared to heifers that were NDP (60.03 ± 3.16 kg). Uterine diameter group, 9-11, 12-13, and 14-20 mm (26.2, 31.3, and 33.3%; P = 0.256), presence and absence of CL (29.8 vs 29.4%; P = 0.975), AI technicians 1, 2, and 3 (32.6, 28.8, and 22.4%; P = 0.293) and sires A, B, and C (23.9, 36.0 and 27.0%; P = 0.122) had no effect on PR to FTAI, natural mating, or overall. In conclusion, treatment of primarily cycling Brahman heifers with 300 IU eCG in conjunction with a low P(4)-dose (0.78 g) IPRD and EB to synchronize ovulation, did not improve PR after FTAI, natural mating, or overall. Copyright © 2011 Elsevier Inc. All rights reserved.

4. 99 Tc靶件中子学特性及释热率特点的初步研究%Preliminary Study on the Neutronics and the Heat Releasing Rate Characteristics of 99 Tc Transmutation Target

贾晓淳; 于涛; 谢金森

2015-01-01

99 Tc是一种重要的长寿命裂变产物，半衰期长，极易随地下水迁徙扩散.将99 Tc嬗变为短寿命或稳定核素，可有效降低其对环境的危害.99 Tc在热中子谱下具有较大的吸收截面，采用PWR 嬗变99 Tc 是一种可行途径.为了评估99 Tc 嬗变靶件对PWR堆芯中子学参数的影响，并为含嬗变靶件的PWR组件热工水力计算提供数据，本文对含99 Tc的17×17 PWR组件进行模拟计算，给出了99 Tc靶件加入前后，燃料温度系数、慢化剂温度系数的变化规律；计算了稳态工况下99 Tc靶件的轴向释热率.相关结论可为PWR嬗变99 Tc研究提供参考.%99 Tc is a kind of important long-lived fission products with a very long half-life, which is easy to migrate with water underground. Transmuting 99 Tc to short life or stable nuclides will effectively reduce its harm to the environment. As 99 Tc has larger absorption cross section in the thermal neutron spectrum,it is a feasible way to transmute it in PWRs. In order to estimate the influence on the core neutronics parameters after putting the 99 Tc target into PWR,and to provide data for the thermal hydraulic calculation of PWR contai-ning targets, the article has caculated fuel temperature coefficient, moderator temperature coefficient before and after putting 99 Tc into a 17 × 17 PWR assembly and axial heat re-leasing rate of the 99 Tc target in steady state condition. The relevant conclusion can provide reference for the continued study of 99 Tc transmutation in PWR.

5. Free boundary problems in controlled release pharmaceuticals: II. swelling-controlled release

Cohen, Donald S.; Erneux, Thomas

1988-01-01

A problem in controlled release pharmaceutical systems is formulated and studied. The device modeled is a polymer matrix containing an initially immobilized drug. The release of the drug is achieved by countercurrent diffusion through a penetrant solvent with the release rate being determined by the rate of diffusion of the solvent in the polymer. The mathematical theory yields a free boundary problem which is studied in various asymptotic regimes.

6. SYNTHESIS AND DRUG RELEASE OF CROSSLINKING POLYPHOSPHATES

LuoYi; ZhuoRenxi; 等

1995-01-01

A new class of crosslinking polyphosphates were synthesized and characterized by IR 1HNMR,31PNMR spectroscopy as well as elemental analysis.In vitro degradation of the polyphosphates obtained and the release of antineoplastic drug Methotrexate(MTX) and contraceptive Levonorgestrel(LNG) by using these polymers as matrix were studied.Zero order release rate was observed in the case of LNG release.

7. Effects of Decreasing Controlled- release Fertilizer Application Rate on Yield and Quality of Potato, and Soil Nitrate Nitrogen Content%控释肥减量施用对马铃薯产量、品质及土壤硝态氮含量的影响

董亮; 张玉凤; 刘苹; 于淑芳; 杨力; 杨鹏

2012-01-01

The effects of decreasing the application rate of controlled - release coated urea on the yield and quality of potato, and soil nitrate nitrogen content were studied through field experiments. The results indicated that the controlled - release fertilizer treatment increased the first grade rate of potato tube as compared with the traditional fertilization, enhanced potato yield by 8. 00% -25.59% , and the best yield - increasing effect was obtained in the treatment of applying 100% controlled - release fertilizer. Decreasing the application rate of controlled - release fertilizer improved potato quality, increased the utilization rate of nitrogen fertilizer by 10.53% ～22.69% , and the utilization rate of nitrogen fertilizer was the highest in the treatment of decreasing 40% nitrogen of controlled - release fertilizer. The controlled - release fertilizer treatment reduced soil nitrate nitrogen accumulation in each soil layer, and decreasing 30% ～ 40% nitrogen of controlled - release fertilizer achieved the least soil nitrate nitrogen accumulation.%通过田间试验,研究了包膜尿素减量化施用对马铃薯产量、品质及土壤硝态氮含量的影响.结果表明,与习惯施肥处理相比,花用控释肥可以提高马铃薯的一级品率,并且能较好地保证马铃薯产量,马铃薯产量增加8.00％～25.59％,以100％控释肥增产效果最好.马铃薯品质方面,减氮控释肥处理能提高马铃薯品质.施用控释肥可以提高氮肥利用率10.53％～22.69％,其中,以减氮40％控释肥的氮肥利用率最高.在马铃薯土壤硝态氮含量方面,施用控释肥能降低硝态氮在各个土层的累积,其中减氮30％～40％控释肥处理土壤硝态氮的累积量最低.

8. Toxics Release Inventory (TRI)

U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) is a dataset compiled by the U.S. Environmental Protection Agency (EPA). It contains information on the release and waste...

9. CERCLA and EPCRA Continuous Release Reporting

Congress established reportable quantities for Superfund hazardous substances. A continuous release of a hazardous substance is defined as being without interruption or abatement and stable in quantity and rate.

10. Recent patents in flavor controlled release.

Feng, Tao; Xiao, Zuobing; Tian, Huaixiang

2010-06-01

In recent years, considerable effort has been directed toward the preparation of flavoring materials specifically, flavor materials have been sought that provide greater flavor intensity coupled with controlled flavor release for long periods of time. Here, some recent patents related to controlled flavor release are reviewed from the angle of its application field, its mechanism and its determination method. It is found that controlled flavor release often depends not only on materials' chemical and physical properties, such as melting point, solution properties and so on, but also on flavors' chemical and physical properties, such as diffusion capacity, its stability in different media etc. Meanwhile, flavor release is also controlled by an electric reducing device according to the flavor generation condition. It might be also known that flavor release rate could be determined by using a purge-and-trap/gas chromatographic procedure. In future, it's necessary to use mathematical model to study the kinetic behavior of controlled flavor release.

11. Release Data Package for Hanford Site Assessments

Riley, Robert G.; Lopresti, Charles A.; Engel, David W.

2006-07-01

Beginning in fiscal year (FY) 2003, the U.S. Department of Energy (DOE) Richland Operations Office initiated activities, including the development of data packages, to support a Hanford assessment. This report describes the data compiled in FY 2003 through 2005 to support the Release Module of the System Assessment Capability (SAC) for the updated composite analysis. This work was completed as part of the Characterization of Systems Project, part of the Remediation and Closure Science Project, the Hanford Assessments Project, and the Characterization of Systems Project managed by Pacific Northwest National Laboratory. Related characterization activities and data packages for the vadose zone and groundwater are being developed under the remediation Decision Support Task of the Groundwater Remediation Project managed by Fluor Hanford, Inc. The Release Module applies release models to waste inventory data from the Inventory Module and accounts for site remediation activities as a function of time. The resulting releases to the vadose zone, expressed as time profiles of annual rates, become source terms for the Vadose Zone Module. Radioactive decay is accounted for in all inputs and outputs of the Release Module. The Release Module is implemented as the VADER (Vadose zone Environmental Release) computer code. Key components of the Release Module are numerical models (i.e., liquid, soil-debris, cement, saltcake, and reactor block) that simulate contaminant release from the different waste source types found at the Hanford Site. The Release Module also handles remediation transfers to onsite and offsite repositories.

12. ELECTROMAGNETIC RELEASE MECHANISM

Michelson, C.

1960-09-13

An electromagnetic release mechanism is offered that may be used, for example, for supporting a safety rod for a nuclear reactor. The release mechanism is designed to have a large excess holding force and a rapid, uniform, and dependable release. The fast release is accomplished by providing the electromagnet with slotttd polts separated by an insulating potting resin, and by constructing the poles with a ferro-nickel alloy. The combination of these two features materially reduces the eddy current power density whenever the magnetic field changes during a release operation. In addition to these features, the design of the armature is such as to provide ready entrance of fluid into any void that might tend to form during release of the armature. This also improves the release time for the mechanism. The large holding force for the mechanism is accomplished by providing a small, selected, uniform air gap between the inner pole piece and the armature.

13. Preliminary Study on Release Rate of Paeoniflorin in Paeonia lactiflora Processed Products by Water Extraction%白芍炮制品中芍药苷水提取释放速度的初步研究

殷钢; 吴健; 夏侯福

2011-01-01

Objective: To investigate release discipline of paeoniflorin in different processed Paeonia lactiflora in boiling process. Method; P. Lactiflora processed products were boiled alone. HPLC was used to determine the content of paeoniflorin in boiling liquid and decoction pieces. Result; The content of paeoniflorin in P. Lactiflora decreased after processed. P. Lactiflora carbon and baked P. Lactiflora decreased the lowest, release speed in baked P. Lactiflora was the highest during 30 min. The content of paeoniflorin in P. Lactiflora and baked P. Lactiflora was the highest after boiled. Conclusion; Processing made paeoniflorin declined in all processed products, declined most significant were P. Lactiflora and baked P. Lactiflora; but it could increase release speed, especial in baked P. Lactiflora.%目的:考察不同炮制品在煎煮过程当中对芍药苷浸出的释放规律.方法:单独煎煮芍药炮制品饮片.HPLC测定煎煮液与饮片中芍药苷含量.结果:白芍经炮制后其芍药苷含量均下降,焦白芍和白芍炭下降最多.30 min内,焦白芍释放最快,芍药苷煎出量,以生白芍与焦白芍为高.结论:各种炙法炮制芍药,均会造成芍药苷含量下降,以白芍炭和焦白芍下降最显著；炮制对煎煮过程中芍药苷的释放有明显促进作用,焦白芍释放速度最快.

14. Release the Body, Release the Mind.

Stoner, Martha Goff

1998-01-01

A college English teacher describes the anxiety and resentment of students during in-class writing assignments and the successful classroom use of meditation and body movement. Movement seemed to relax the students, change their attitudes, and release their creative impulses to write. Implications related to the body-mind connection are pondered.…

15. Lubiprostone stimulates small intestinal mucin release

De Lisle Robert C

2012-11-01

Full Text Available Abstract Background Lubiprostone is a synthetic bicyclic fatty acid derivative of prostaglandin E1 (PGE1 used for chronic constipation. The best known action of lubiprostone is simulation of Cl- dependent fluid secretion. In a mouse model of the genetic disease cystic fibrosis, we previously showed that in vivo administration of lubiprostone resulted in greater mucus accumulation in the small intestine. The aim of this study was to directly test whether lubiprostone stimulates intestinal mucin release. Methods Mucin release was measured by mounting segments (4-5 cm of mouse proximal-mid small intestine in an organ bath, allowing access to the perfusate (luminal and the bath (serosal solutions. Nifedipine (10-6 M and indomethacin (10-5 M were included in all solutions to inhibit smooth muscle activity and endogenous prostaglandin production, respectively. The tissue was equilibrated under flow for 30 min, using the perfusate collected during the final 10 min of the equilibration period to measure unstimulated release rate. Stimulus was then added to either the perfusate or the bath and the perfusate was collected for another 30 min to measure the stimulated mucin release rate. Mucin in perfusates was quantified by periodic acid-Schiff's base dot-blot assay, using purified pig gastric mucin as a standard. Results When applied luminally at 1 μM lubiprostone was ineffective at stimulating mucin release. When added to the serosal solution, 1 μM lubiprostone stimulated mucin release to ~300% of the unstimulated rate. As a positive control, serosal 1 μM prostaglandin E2 increased mucin release to ~400% of the unstimulated rate. Conclusions These results support the idea that lubiprostone has prostaglandin-like actions on the intestine, which includes stimulation of mucin release. Stimulation of mucin release by lubiprostone may be protective in gastrointestinal conditions where loss of mucus is believed to contribute to pathogenesis. Thus, in

16. Effect of transfer of one or two in vitro-produced embryos and post-transfer administration of gonadotropin releasing hormone on pregnancy rates of heat-stressed dairy cattle.

Franco, M; Block, J; Jousan, F D; de Castro e Paula, L A; Brad, A M; Franco, J M; Grisel, F; Monson, R L; Rutledge, J J; Hansen, P J

2006-07-15

Pregnancy rates following transfer of an in vitro-produced (IVP) embryo are often lower than those obtained following transfer of an embryo produced by superovulation. The purpose of the current pair of experiments was to examine two strategies for increasing pregnancy rates in heat stressed, dairy recipients receiving an IVP embryo. One method was to transfer two embryos into the uterine horn ipsilateral to the CL, whereas the other method involved injection of GnRH at Day 11 after the anticipated day of ovulation. In Experiment 1, 32 virgin crossbred heifers and 26 lactating crossbred cows were prepared for timed embryo transfer by being subjected to a timed ovulation protocol. Those having a palpable CL were randomly selected to receive one (n = 31 recipients) or two (n = 27 recipients) embryos on Day 7 after anticipated ovulation. At Day 64 of gestation, the pregnancy rate tended to be higher (P = 0.07) for cows than for heifers. Heifers that received one embryo tended to have a higher pregnancy rate than those that received two embryos (41% versus 20%, respectively) while there was no difference in pregnancy rate for cows that received one or two embryos (57% versus 50%, respectively). Pregnancy loss between Day 64 and 127 only occurred for cows that received two embryos (pregnancy rate at Day 127=17%). Between Day 127 and term, one animal (a cow with a single embryo) lost its pregnancy. There was no difference in pregnancy rates at Day 127 or calving rates between cows and heifers, but females that received two embryos had lower Day-127 pregnancy rates and calving rates than females that received one embryo (P cows were synchronized for timed embryo transfer as in Experiment 1. Cows received a single embryo in the uterine horn ipsilateral to the ovary containing the CL and received either 100 microg GnRH or vehicle at Day 11 after anticipated ovulation (i.e. 4 days after embryo transfer). There was no difference in pregnancy rate for cows that received the Gn

17. Design and evaluation of nicorandil extended-release tablet

Ju-Young Kim

2015-04-01

Full Text Available The aim of this study was to design and evaluate extended-release formulations of a model drug, nicorandil, in order to achieve the desired steady-state plasma concentration of drug in vivo. Simulation was employed to estimate optimum dissolution and absorption rate of nicorandil. The dissolution test was employed using pH 1.2, 4.0, 6.8 buffer solution, or water, to measure the in vitro release behaviors of nicorandil formulations. A single dose (15 mg of each formulation was orally administered to four beagle dogs under fasted conditions, and the pharmacokinetic parameters were calculated. The in vitro/in vivo relationship of the extended-release formulation was confirmed using in vitro dissolution profiles and plasma concentrations of drug in beagle dogs. Nicorandil was released completely within 30 min from the immediate-release tablets and released for 24 h from the extended-release tablets. The nicorandil plasma concentration could be modified by adjusting the drug release rate from the extended-release formulation. The release rate of nicorandil was the rate-limiting step in the overall absorption of drug from the extended-release formulations. These results highlight the potential of a nicorandil extended-release formulation in the treatment of angina pectoris.

18. Dual trigger with combination of gonadotropin-releasing hormone agonist and human chorionic gonadotropin significantly improves the live-birth rate for normal responders in GnRH-antagonist cycles

Lin, Ming-Huei; Wu, Frank Shao-Ying; Lee, Robert Kuo-Kuang; Li, Sheng-Hsiang; Lin, Shyr-Yeu; Hwu, Yuh-Ming

2013-01-01

...) agonist and human chorionic gonadotropin (hCG) can improve the live-birth rate for normal responders in GnRH-antagonist in vitro fertilization/intracytoplasmic sperm injection (IVF-ICSI) cycles...

19. Guar gum, xanthan gum, and HPMC can define release mechanisms and sustain release of propranolol hydrochloride.

Mughal, Muhammad Akhlaq; Iqbal, Zafar; Neau, Steven Henry

2011-03-01

The objectives were to characterize propranolol hydrochloride-loaded matrix tablets using guar gum, xanthan gum, and hydroxypropylmethylcellulose (HPMC) as rate-retarding polymers. Tablets were prepared by wet granulation using these polymers alone and in combination, and physical properties of the granules and tablets were studied. Drug release was evaluated in simulated gastric and intestinal media. Rugged tablets with appropriate physical properties were obtained. Empirical and semi-empirical models were fit to release data to elucidate release mechanisms. Guar gum alone was unable to control drug release until a 1:3 drug/gum ratio, where the release pattern matched a Higuchi profile. Matrix tablets incorporating HPMC provided near zero-order release over 12 h and erosion was a contributing mechanism. Combinations of HPMC with guar or xanthan gum resulted in a Higuchi release profile, revealing the dominance of the high viscosity gel formed by HPMC. As the single rate-retarding polymer, xanthan gum retarded release over 24 h and the Higuchi model best fit the data. When mixed with guar gum, at 10% or 20% xanthan levels, xanthan gum was unable to control release. However, tablets containing 30% guar gum and 30% xanthan gum behaved as if xanthan gum was the sole rate-retarding gum and drug was released by Fickian diffusion. Release profiles from certain tablets match 12-h literature profiles and the 24-h profile of Inderal(®) LA. The results confirm that guar gum, xanthan gum, and HPMC can be used for the successful preparation of sustained release oral propranolol hydrochoride tablets.

20. Thermoresponsive latexes for fragrance encapsulation and release.

2016-04-01

To synthesize cross-linked latex particles protecting the encapsulated fragrance at ambient temperatures and facilitating the release of cargo at the temperature of the surface of the skin that varies in different regions of the body between 33.5 and 36.9°C. Poly(stearyl acrylate) (PSA), a polymer with long crystallizable alkyl side chains (undergoes order-disorder transitions at 45°C), was chosen as the main component of the polymer particles. As a result, new thermoresponsive polymer particles for fragrance encapsulation were synthesized and characterized, including assessing the performance of particles in triggered release by elevated temperature. To obtain network domains of various crystallinity, stearyl acrylate was copolymerized with dipropylene glycol acrylate caprylate (DGAC) (comonomer) in the presence of a dipropylene glycol diacrylate sebacate (cross-linker) using the miniemulsion process. Comonomers and a cross-linker were mixed directly in a fragrance during polymerization. Fragrance release was evaluated at 25, 31, 35 and 39°C to demonstrate a new material potential in personal/health care skin-related applications. Particles protect the fragrance from evaporation at 25°C. The fragrance release rate gradually increases at 31, 35 and 39°C. Two slopes were found on release plots. The first slope corresponds to a rapid fragrance release. The second slope indicates a subsequent reduction in the release rate. Crystalline-to-amorphous transition of PSA triggers the release of fragrances from cross-linked latex particles at elevated temperatures. The presence of the encapsulated fragrance, as well as the inclusion of amorphous fragments in the polymer network, reduces the particle crystallinity and enhances the release. Release profiles can be tuned by temperature and controlled by the amount of loaded fragrance and the ratio of comonomers in the feed mixture. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

1. Morphology of Gas Release in Physical Simulants

Daniel, Richard C.; Burns, Carolyn A.; Crawford, Amanda D.; Hylden, Laura R.; Bryan, Samuel A.; MacFarlan, Paul J.; Gauglitz, Phillip A.

2014-07-03

This report documents testing activities conducted as part of the Deep Sludge Gas Release Event Project (DSGREP). The testing described in this report focused on evaluating the potential retention and release mechanisms of hydrogen bubbles in underground radioactive waste storage tanks at Hanford. The goal of the testing was to evaluate the rate, extent, and morphology of gas release events in simulant materials. Previous, undocumented scoping tests have evidenced dramatically different gas release behavior from simulants with similar physical properties. Specifically, previous gas release tests have evaluated the extent of release of 30 Pa kaolin and 30 Pa bentonite clay slurries. While both materials are clays and both have equivalent material shear strength using a shear vane, it was found that upon stirring, gas was released immediately and completely from bentonite clay slurry while little if any gas was released from the kaolin slurry. The motivation for the current work is to replicate these tests in a controlled quality test environment and to evaluate the release behavior for another simulant used in DSGREP testing. Three simulant materials were evaluated: 1) a 30 Pa kaolin clay slurry, 2) a 30 Pa bentonite clay slurry, and 3) Rayleigh-Taylor (RT) Simulant (a simulant designed to support DSGREP RT instability testing. Entrained gas was generated in these simulant materials using two methods: 1) application of vacuum over about a 1-minute period to nucleate dissolved gas within the simulant and 2) addition of hydrogen peroxide to generate gas by peroxide decomposition in the simulants over about a 16-hour period. Bubble release was effected by vibrating the test material using an external vibrating table. When testing with hydrogen peroxide, gas release was also accomplished by stirring of the simulant.

2. Study of LPG Release & Dispersion Model

Mu Shanjun; Peng Xiangwei

2003-01-01

The current applicable release & dispersion models are reviewed. A typical model is developed on the basis of LPG storage conditions in China and the authors' research. The study is focused on the relationship between LPG composition and release rate, and on the influence of buildings or structures located in the surrounding area on the dispersion of gas plume. The established model is compared with existing models by the use of published field test data.

3. Gas Release as a Deformation Signal

Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

Radiogenic noble gases are contained in crustal rock at inter and intra granular sites. The gas composition depends on lithology, geologic history, fluid phases, and the aging effect by decay of U, Th, and K. The isotopic signature of noble gases found in rocks is vastly different than that of the atmosphere which is contributed by a variety of sources. When rock is subjected to stress conditions exceeding about half its yield strength, micro-cracks begin to form. As rock deformation progresses a fracture network evolves, releasing trapped noble gases and changing the transport properties to gas migration. Thus, changes in gas emanation and noble gas composition from rocks could be used to infer changes in stress-state and deformation. The purpose of this study has been to evaluate the effect of deformation/strain rate upon noble gas release. Four triaxial experiments were attempted for a strain rate range of %7E10-8 /s (180,000s) to %7E 10-4/s (500s); the three fully successful experiments (at the faster strain rates) imply the following: (1) helium is measurably released for all strain rates during deformation, this release is in amounts 1-2 orders of magnitude greater than that present in the air, and (2) helium gas release increases with decreasing strain rate.

4. Intracellular drug release nanosystems

Fenghua Meng

2012-10-01

Full Text Available In order to elicit therapeutic effects, many drugs including small molecule anticancer drugs, proteins, siRNA, and DNA have to be delivered and released into the specific cellular compartments typically the cytoplasm or nucleus of target cells. Intracellular environment-responsive nanosystems that exhibit good extracellular stability while rapidly releasing drugs inside cancer cells have been actively pursued for effective cancer therapy. Here, we highlight novel designs of smart nanosystems that release drugs in response to an intracellular biological signal of cancer cells such as acidic pH in endo/lysosomal compartments, enzymes in lysosomes, and redox potential in cytoplasm and the cell nucleus.

5. Electrosprayed nanoparticle delivery system for controlled release

Eltayeb, Megdi, E-mail: megdi.eltayeb@sustech.edu [Department of Biomedical Engineering, Sudan University of Science and Technology, PO Box 407, Khartoum (Sudan); Stride, Eleanor, E-mail: eleanor.stride@eng.ox.ac.uk [Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Headington OX3 7DQ (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Harker, Anthony, E-mail: a.harker@ucl.ac.uk [London Centre for Nanotechnology, Gordon Street, London WC1H 0AH (United Kingdom); Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

2016-09-01

This study utilises an electrohydrodynamic technique to prepare core-shell lipid nanoparticles with a tunable size and high active ingredient loading capacity, encapsulation efficiency and controlled release. Using stearic acid and ethylvanillin as model shell and active ingredients respectively, we identify the processing conditions and ratios of lipid:ethylvanillin required to form nanoparticles. Nanoparticles with a mean size ranging from 60 to 70 nm at the rate of 1.37 × 10{sup 9} nanoparticles per minute were prepared with different lipid:ethylvanillin ratios. The polydispersity index was ≈ 21% and the encapsulation efficiency ≈ 70%. It was found that the rate of ethylvanillin release was a function of the nanoparticle size, and lipid:ethylvanillin ratio. The internal structure of the lipid nanoparticles was studied by transmission electron microscopy which confirmed that the ethylvanillin was encapsulated within a stearic acid shell. Fourier transform infrared spectroscopy analysis indicated that the ethylvanillin had not been affected. Extensive analysis of the release of ethylvanillin was performed using several existing models and a new diffusive release model incorporating a tanh function. The results were consistent with a core-shell structure. - Highlights: • Electrohydrodynamic spraying is used to produce lipid-coated nanoparticles. • A new model is proposed for the release rates of active components from nanoparticles. • The technique has potential applications in food science and medicine. • Electrohydrodynamic processing controlled release lipid nanoparticles.

6. Miniature Release Mechanism Project

National Aeronautics and Space Administration — The objective is to design, build and functionally test a miniature release mechanism for CubeSats and other small satellites. The WFF 6U satellite structure will be...

7. Evaluation of three approaches to meniscal release.

Austin, B; Montgomery, R D; Wright, J; Bellah, J R; Tonks, C

2007-01-01

Three approaches to medial meniscal release (MMR) were compared using 48 canine cadaver stifles. The approaches included a caudomedial arthrotomy approach, a blind stab incision based on anatomic landmarks, and an arthroscopic guided approach. The cranial cruciate ligament was intact in all specimens. The time required to perform the meniscal release and joint capsule closure was recorded, as well as completeness and location of the meniscal transection. Damage to the caudal cruciate ligament, femoral cartilage, and medial collateral ligament were recorded. The mini-arthrotomy was 81% successful in accomplishment of MMR with a 4% rate of iatrogenic damage. The blind technique was 56% successful in the accomplishment of MMR with a 4% rate of iatrogenic damage. The arthroscopic guided approach was 62.5% successful in accomplishment of MMR, with a 10% rate of iatrogenic damage. Accomplishment and iatrogenic damage rates were not significantly different among procedures (p > 0.05). Significantly less time was required to perform the blind technique, and significantly greater time was required to perform the arthroscopic guided technique (p > 0.05). Significant differences were not noted among the procedures regarding the ability to accomplish the meniscal release or damage surrounding structures. None of the evaluated approaches for meniscal release resulted in a complete and accurate meniscal release for over 81% of the time.

8. Helium release from radioisotope heat sources

Peterson, D.E.; Early, J.W.; Starzynski, J.S.; Land, C.C.

1984-05-01

Diffusion of helium in /sup 238/PuO/sub 2/ fuel was characterized as a function of the heating rate and the fuel microstructure. The samples were thermally ramped in an induction furnace and the helium release rates measured with an automated mass spectrometer. The diffusion constants and activation energies were obtained from the data using a simple diffusion model. The release rates of helium were correlated with the fuel microstructure by metallographic examination of fuel samples. The release mechanism consists of four regimes, which are dependent upon the temperature. Initially, the release is controlled by movement of point defects combined with trapping along grain boundaries. This regime is followed by a process dominated by formation and growth of helium bubbles along grain boundaries. The third regime involves volume diffusion controlled by movement of oxygen vacancies. Finally, the release at the highest temperatures follows the diffusion rate of intragranular bubbles. The tendency for helium to be trapped within the grain boundaries diminishes with small grain sizes, slow thermal pulses, and older fuel.

9. Sustain-release of various drugs from leucaena leucocephala polysaccharide.

Jeevanandham, S; Sekar, M; Dhachinamoorthi, D; Muthukumaran, M; Sriram, N; Joysaruby, J

2010-01-01

This study examines the sustained release behavior of both water-soluble (acetaminophen, caffeine, theophylline and salicylic acid) and water-insoluble (indomethacin) drugs from Leucaena leucocephala seed Gum isolated from Leucaena leucocephala kernel powder. It further investigates the effect of incorporation of diluents like microcrystalline cellulose and lactose on release of caffeine and partial cross-linking of the gum (polysaccharide) on release of acetaminophen. Applying exponential equation, the mechanism of release of soluble drugs was found to be anomalous. The insoluble drug showed near case II or zero-order release mechanism. The rate of release was in the decreasing order of caffeine, acetaminophen, theophylline, salicylic acid and indomethacin. An increase in release kinetics of drug was observed on blending with diluents. However, the rate of release varied with type and amount of blend in the matrix. The mechanism of release due to effect of diluents was found to be anomalous. The rate of release of drug decreased on partial cross-linking and the mechanism of release was found to be super case II.

10. Kinetics of Cd Release from Some Contaminated Calcareous Soils

Sajadi Tabar, S.; Jalali, M., E-mail: jalali@basu.ac.ir [Bu-Ali Sina University, Department of Soil Science, College of Agriculture (Iran, Islamic Republic of)

2013-03-15

Contamination of soils with heavy metals may pose long-term risk to groundwater quality leading to health implications. Bioavailability of heavy metals, like cadmium (Cd) is strongly affected by sorption and desorption processes. The release of heavy metals from contaminated soils is a major contamination risks to natural waters. The release of Cd from contaminated soils is strongly influenced by its mobility and bioavailability. In this study, the kinetics of Cd desorption from ten samples of contaminated calcareous soils, with widely varying physicochemical properties, were studied using 0.01 M EDTA extraction. The median percentage of Cd released was about 27.7% of the total extractable Cd in the soils. The release of Cd was characterized by an initial fast release rate (of labile fractions) followed by a slower release rate (of less labile fractions) and a model of two first-order reactions adequately describes the observed release of Cd from the studied soil samples. There was positive correlation between the amount of Cd released at first phase of release and Cd in exchangeable fraction, indicating that this fraction of Cd is the main fraction controlling the Cd in the kinetic experiments. There was strongly negative correlation between the amount of Cd released at first and second phases of release and residual fraction, suggesting that this fraction did not contribute in Cd release in the kinetic experiments. The results can be used to provide information for evaluation of Cd potential toxicity and ecological risk from contaminated calcareous soils.

11. Compounding of slow-release niacinamide capsules: feasibility and characterization.

Radojkovic, Branko; Milić, Jela; Calija, Bojan

2012-01-01

The purpose of this study was to assess the feasibility of extemporaneous compounding of slow-release oral dosage form of niacinamide and to evaluate its release kinetics. The model formulation (preparation) was developed in the form of powder-filled hard gelatin capsules. Two slow-release preparations with different ratios of hypromellose have been prepared and evaluated in comparison with an immediate-release preparation. The dissolution tests were performed as per United States Pharmacopoeia requirements: Type I Apparatus, over 7 hours. Both slow-release preparations, containing 40% and 60% v/v hypromellose, respectively, have showed slow release kinetics. The dissolution profiles were significantly different, with similarity factor f2niacinamide capsules can be successfully compounded using hypromellose as a sole release rate modifier, and that the release mechanism is comparable to hydrophilic polymer matrix-based systems.

12. Modifying sorbents in controlled release formulations to prevent herbicides pollution

Cespedes, F.F.; Sanchez, M.V.; Garcia, S.P.; Perez, M.F. [University of Almeria, Almeria (Spain). Dept. of Inorganic Chemistry

2007-10-15

The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in alginate-based granules to obtain controlled release properties. In this research the effect of incorporation of sorbents such as bentonite, anthracite and activated carbon in alginate basic formulation were not only studied on encapsulation efficiency but also on the release rate of herbicides which was studied using water release kinetic tests. In addition, sorption studies of herbicides with bentonite, anthracite and activated carbon were made. The kinetic experiments of chloridazon and metribuzin release in water have shown that the release rate is higher in metribuzin systems than in those prepared with chloridazon, which has lower water solubility. Besides, it can be deduced that the use of sorbents reduces the release rate of the chloridazon and metribuzin in comparison to the technical product and to the alginate formulation without sorbents. The highest decrease in release rate corresponds to the formulations prepared with activated carbon as a sorbent. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the herbicide release data, the release of chloridazon and metribuzin from the various formulations into water is controlled by a diffusion mechanism.

13. 冬小麦上短控释期尿素的适宜施用量与施用方法研究%Study on the suitable application rate and method of urea with short controlled-release period in winter wheat

靳海洋; 谢迎新; 刘园; 马冬云; 朱云集; 王晨阳; 贺德先

2016-01-01

[Objectives]The application effect of controlled-release urea is usually affected by temperature, soil moisture and other environmental factors, so the reported effect was varied.To provide theoretical and technical supports for selecting the appropriate nitrogen fertilizers and application methods, two comparison experiments between the controlled-release urea and common urea application on winter wheat were performed.[Methods] A wheat cultivar, Xinmai 26 was used as the experimental crop, and two field experiments were designed with a randomized block.Grain yield,quality traits,nitrogen use efficiency and economic benefit of winter wheat between controlled-release urea and common urea were systematically studied.In the 1st experiment, the controlled-release urea was basal applied in one time, and 60% of commercial urea was basal applied and 40% top dressed at reviving stage, all the two kinds of urea were applied in the five levels:0(CK1),120,160,200 and 240 kg/hm2, respectively.In the second experiment, using no N fertilizer as control(CK2),200 kg/hm2 of N was applied, and controlled-release urea and commercial urea were all applied in ratio of top-dressed 40%.[Results] 1 ) Compared to CK1,grain yield of winter wheat was significantly increased with the increase of nitrogen application rates of both controlled-release urea and common urea,and the treatment with common urea split application reached the highest grain yield as much as N 240 kg/hm2 .Compared with controlled-release urea one-time application at the same nitrogen rate, the treatment with common urea split application could significantly increase grain yield of winter wheat but not exhibit significant difference at the N 160 kg/hm2 nitrogen rate.However,compared with topdressing common urea at reviving stage,topdressing controlled-release urea could significantly increase grain yield of winter wheat by 15.8%.2) Under the same nitrogen rate,compared with controlled-release urea one-time application as

14. A fluoride release-adsorption-release system applied to fluoride-releasing restorative materials.

Suljak, J P; Hatibovic-Kofman, S

1996-09-01

This investigation compared the initial fluoride release and release following refluoridation of three resin-modified glass-ionomer cements (Photac-Fil Applicap, Vitremer, and Fuji II LC) and a new polyacid-modified resin composite material (Dyract). After daily flouride release was measured for 8 days, specimens were refluoridated in 1,000-ppm solutions of fluoride ion for 10 minutes and fluoride release was measured for 5 days. Two further 5-day refluoridation-release periods were carried out. All materials released fluoride initially. Photac released the most; Dyract released the least. Initial release was greatest over the first few days. All materials released significantly more fluoride for 24 to 48 hours after refluoridation. Less fluoride was released with each successive refluoridation for the three glass-ionomer cements. The release from the Dyract compomer remained at a comparatively constant and significantly lower level following each refluoridation.

15. Higher Death Rate Among Youth With First Episode Psychosis

... Releases News Release Thursday, April 6, 2017 Higher death rate among youth with first episode psychosis NIH- ... experiencing first episode psychosis have a much higher death rate than previously thought. Researchers analyzed data on ...

16. [Preparation and drug releasing property of curcumin nanoparticles].

Liu, Zhan-jun; Han, Gang; Yu, Jiu-gao; Dai, Hong-guang

2009-02-01

To prepare curcumin nanoparticles and evaluate the in vitro release of curcumin. The chitosan-graft-vinyl acetate copolymers were synthesized by free radical polymerization. Curcumin nanoparticles were synthesized by ultrasonic irradiation. The encapsulation efficiency of the nanoparticles and the in vitro release of curcumin were studied. The nanoparticles were discrete and uniform spheres, covered with positive charges. The encapsulation efficiency of nanoparticles was up to 91.6%. The in vitro release profile showed the slower release rate of curcumin. The methods is simple. The nanoparticles possess good physical performance and sustained release character in vitro.

17. Evaluation of a soil incubation method to characterize nitrogen release patterns of slow- and controlled-release fertilizers.

Medina, L Carolina; Sartain, Jerry B; Obreza, Thomas A; Hall, William L; Thiex, Nancy J

2014-01-01

Several technologies have been proposed to characterize the nutrient release patterns of slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) during the last few decades. These technologies have been developed mainly by manufacturers, and are product-specific, based on the regulation and analysis of each SRF and CRF product. Despite previous efforts to characterize SRF and CRF materials, no standardized, validated method exists to assess their nutrient release patterns. However, the increased production and distribution of these materials in specialty and nonspecialty markets requires an appropriate method to verify product claims and material performance. A soil incubation column leaching procedure was evaluated to determine its suitability as a standard method to estimate nitrogen (N) release patterns of SRFs and CRFs during 180 days. The influence of three soil/sand ratios, three incubation temperatures, and four soils on method behavior was assessed using five SRFs and three CRFs. In general, the highest soil/sand ratio increased the N release rate of all materials, but this effect was more marked for the SRFs. Temperature had the greatest influence on N release rates. For CRFs, the initial N release rates and the percentage N released/day increased as temperature increased. For SRFs, raising the temperature from 25 to 35 degreesC increased initial N release rate and the total cumulative N released, and almost doubled the percentage released/day. The percentage N released/day from all products generally increased as the texture of the soil changed from sandy to loamy (lowa>California>Pennsylvania>Florida). The soil incubation technique was demonstrated to be robust and reliable for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and variations in soil/sand ratio, temperature, and soil had little effect on the results.

18. RAVEN Beta Release

Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cogliati, Joshua Joseph [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinoshita, Robert Arthur [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wang, Congjian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Maljovec, Daniel Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Talbot, Paul William [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-02-01

This documents the release of the Risk Analysis Virtual Environment (RAVEN) code. A description of the RAVEN code is provided, and discussion of the release process for the M2LW-16IN0704045 milestone. The RAVEN code is a generic software framework to perform parametric and probabilistic analysis based on the response of complex system codes. RAVEN is capable of investigating the system response as well as the input space using Monte Carlo, Grid, or Latin Hyper Cube sampling schemes, but its strength is focused toward system feature discovery, such as limit surfaces, separating regions of the input space leading to system failure, using dynamic supervised learning techniques. RAVEN has now increased in maturity enough for the Beta 1.0 release.

19. Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales, Australia. III. Release, persistence and rate of spread of an identifiable strain of myxoma virus.

Merchant, J C; Kerr, P J; Simms, N G; Hood, G M; Pech, R P; Robinson, A J

2003-02-01

An identifiable strain of myxoma virus was introduced into four local populations of wild rabbits Oryctolagus cuniculus on the southern tablelands of New South Wales (NSW) and its spread in the presence of other field strains was monitored for 6 months. The main vector in this region was considered to be the European rabbit flea Spilopsyllis cuniculi. Each population of rabbits was of a high density and living in groups of warrens covering areas from 59 to 87 hectares. Rabbits occupying centrally located warrens were inoculated with the virus in late September or early October (spring) and the subsequent appearance of myxomatosis across the sites monitored by trapping, shooting and visual observations. Samples, taken from rabbits with myxomatosis, were examined by polymerase chain reaction (PCR) that allowed identification of the introduced strain. On all four sites the introduced virus spread from the inoculated rabbits in the centrally located warrens to rabbits in surrounding warrens. On Sites 1 and 3, this spread continued across the entire site persisting for at least 118 and 174 days respectively. On Sites 2 and 4, the virus was detected for 78 and 62 days respectively and the subsequent inability to detect the introduced virus correlated with the appearance of an unrelated field strain. Using three different methods of calculation, rates of spread ranged from 3.7 to 17.8 m d(-1).

20. COLLOID RELEASE FROM DIFFERENT SOIL DEPTH

Gang Chen

2013-01-01

Full Text Available Naturally occurring clay colloidal particles are heavily involved in sediment processes in the subsurface soil. Due to the import ance of these processes in the subsurface environment, the transport of clay colloidal particles has been studied in several disciplines, including soil sciences, petr ology, hydrology, etc. Specifically, in environmental engineering, clay colloid re lease and transport in the sediments have been extensively investigated, which are motiv ated by environmental concerns such as colloid-facilitated contaminant transport in groundwater and the subsurface soil. Clay colloid release is resulted from physical alteration of subsurface sediments. Despite the potential importance of clay colloid activiti es, the detailed mechanisms of release and transport of clay colloidal particles with in natural sediments are poorly understood. Pore medium structure, properties and flow dynamics, etc. are factors that affect clay colloid generation, mobilization, and subse quent transport. Possible mechanisms of clay colloid generation in the sediments in clude precipitation, erosion and mobilization by changes in pore water chemistry and clay colloid release depends on a balance of applied hydrodynamic and resisting adhesive torques and forces. The coupled role of pore water chemistry and fluid hydrodynamics thus play key roles in controlling clay colloid release and transport in the sediment s. This paper investigated clay colloidal particle release and transport, especially th e colloidal particle release mechanisms as well as the process modeling in the sediments. In this research, colloidal particle release from intact sediment columns with variable length was examined and colloidal particle release curves were simulated using an im plicit, finite-difference scheme. Colloidal particle release rate coefficient was found to be an exponential function of the sediment depth. The simulated results demonstrated that transport parameters were

1. INVESTIGATION OF DRUG RELEASE FROM BIODEGRADABLE PLG MICROSPHERES: EXPERIMENT AND THEORY

ANDREWS, MALCOLM J. [Los Alamos National Laboratory; BERCHANE, NADER S. [Los Alamos National Laboratory; CARSON, KENNETH H. [Los Alamos National Laboratory; RICE-FICHT, ALLISON C. [Los Alamos National Laboratory

2007-01-30

Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

2. Effect of Metoprolol Sustained-release Tablets on Cardiac Function and Heart Rate Variability in Patients with Chronic Heart Failure%美托洛尔缓释片对慢性心力衰竭患者心功能及心率变异性的影响

张卫娟; 刘焰华

2014-01-01

目的：探讨美托洛尔缓释片对慢性心力衰竭（ CHF ）患者心功能及心率变异性的影响。方法：将62例CHF患者随机分为观察组32例和对照组30例。观察组在常规心衰治疗基础上加用美托洛尔缓释片，对照组给予常规心衰治疗。12个月后，比较两组患者治疗前后心率（ HR）、总有效率、左室射血分数（ LVEF）、左室收缩末期容积（ LVESV）、左室舒张末期容积（LVEDV）、 N末端B型脑钠肽（NT-proBNP）以及心率变异性（HRV）的变化。结果：观察组患者总有效率、 LVEF及HRV显著高于对照组，而HR、 LVESV、 LVEDV、 NT-proBNP 显著低于对照组。差异均有统计学意义。结论：在常规心衰综合治疗基础上，加用美托洛尔缓释片能有效提高CHF患者的临床疗效，明显改善心室重构、心率变异性及心功能，提高患者生活质量，有利于慢性心力衰竭患者的二级预防。%OBJECTIVE: To approach the curative effect of metoprolol sustained -release tablets on cardiac function and heart rate variability in patients with chronic heart failure .METHODS: 62 patients with chronic heart failure ( CHF) were randomly divid-ed into the observation group (n=32) and control group (n=30).The observation group received additional metoprolol sustained -release tablets and the control group were randomly treated routine therapy .After 12 months the changes of total effective rate , blood pressure, heart rate, left ventricular eject fraction (LVEF), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), N-terminal pro-brain natriuretic peptide (NT-proBNP) and heart rate variability (HRV) before and after treatment were compared in this two groups .RESULTS: Total effective rate, heart rate, left ventricular eject fraction ( LVEF) and heart rate variability ( HRV) in depression group were higher than those in control group .But left ventricular end -di

3. Release of OLe peanut

OLe is a high oleic Spanish-type peanut that has excellent yield and enhanced Sclerotinia blight and pod rot resistance when compared to other high oleic Spanish cultivars. The purpose for releasing OLe is to provide peanut producers with a true Spanish peanut that is high oleic and has enhanced yi...

4. Border cell release

Mravec, Jozef

2017-01-01

Plant border cells are specialised cells derived from the root cap with roles in the biomechanics of root growth and in forming a barrier against pathogens. The mechanism of highly localised cell separation which is essential for their release to the environment is little understood. Here I present...

5. Effect of hydroxypropyl methylcellulose and hydrogenated castor oil on naproxen release from sustained-release tablets.

Amaral, M H; Lobo, J M; Ferreira, D C

2001-04-09

The effect of the concentration of hydrophilic (hydroxypropyl methylcellulose [HPMC]) and hydrophobic (hydrogenated castor oil [HCO]) products, fillers (lactose and dibasic calcium phosphate), and buffers (sodium bicarbonate, calcium carbonate, and sodium citrate) on naproxen release rate was studied. Matrix tablets were prepared by double compression, and in vitro dissolution tests were performed. The dissolution results showed that an increased amount of HPMC or hydrogenated castor oil resulted in reduced drug release. The inclusion of buffers in the HPMC matrix tablets enhanced naproxen release. For HCO tablets, only sodium bicarbonate enhanced naproxen release. The presence of lactose on HPMC matrix tablets did not show a significantly different result from that obtained with the formulation containing dibasic calcium phosphate as a filler. However, for the tablets containing HCO, the presence of lactose significantly enhanced the naproxen release rate. The matrix-forming materials in this study were suitable for use in sustained-release tablets containing naproxen. The drug release can be modulated by adding suitable amounts of diluents and buffers.

6. Fluoride release and uptake capacities of fluoride-releasing restorative materials.

Attar, Nuray; Turgut, Melek D

2003-01-01

Many fluoride-releasing dental materials are being sold on the basis of their cariostatic properties. However, the amount fluoride release of these materials is still uncertain. This study investigated the fluoride release and uptake characteristics of four flowable resin composites (Heliomolar Flow, Tetric Flow, Wave, Perma Flo), one flowable compomer (Dyract flow), one conventional glass ionomer cement mixed with two different powder/liquid ratios (ChemFlex Syringeable and ChemFlex Condensable), one packable resin composite (SureFil), one ion-releasing composite (Ariston pHc) and one resin-modified glass ionomer cement (Vitremer). Seven discs (6-mm diameter and 1.5-mm height) were prepared for each material. Each disc was immersed in 3.5 ml of deionized water within a plastic vial and stored at 37 degrees C. The deionized water was changed every 24 hours and the release of fluoride was measured for 30 days. At the end of this period, the samples were recharged with 2 ml of 1.23% acidulated phosphate fluoride (APF) gel for four minutes. Then, all samples were reassessed for an additional 10 days. The fluoride release of all samples was measured with a specific fluoride electrode and an ionanalyzer. Statistical analyses were conducted using two-way repeated measure ANOVA and Duncan's multiple range tests. For all tested materials, the greatest fluoride release was observed after the first day of the study (p0.05). Ariston pHc released the highest amount of fluoride, followed by ChemFlex Syringeable, Vitremer and ChemFlex Condensable. There were statistically significant differences among these materials (p<0.05). Fluoride release of all materials were significantly increased after the first day following refluoridation and Ariston pHc released the greatest among all materials (p<0.01). At the end of two days of refluoridation, the fluoride release rate for each material dropped quickly and stabilized within three days.

7. Studies of release properties of ISOLDE targets

Peräjärvi, K; Fedosseev, V; Joinet, A; Köster, U; Lau, C; Lettry, Jacques; Ravn, H L; Santana-Leitner, M

2003-01-01

Off-line release rates of Be, Mg, S, Mn and Kr from refractory materials were studied. Mn yields were determined from a ZrO2 target and Kr yields from a SrO and ZrO2 targets. A Monte Carlo code to optimize ISOLDE targets was introduced.

8. Effect of hydrophilic and hydrophobic polymers on release kinetics of metoprolol succinate extended release tablets

2011-01-01

Full Text Available The purpose of the present work is to design and evaluate extended release matrix tablets of metoprolol succinate to reduce the dosing frequency and to improve patient compliance. The matrix tablets were prepared by the combination of hydrophilic and hydrophobic polymers, using methocel 10000 Cps in combination with ethyl cellulose 7 Cps, Eudragit® RS100, Eudragit® S100, and Eudragit® L100.The tablets were prepared by direct compression technique. Prepared formulations were evaluated for various parameters like weight variation, thickness, hardness, friability, and % drug content. Tablets were subjected to in vitro drug release studies. The formulations containing methocel 10000 Cps, Eudragit® L100 showed good release retardation. All the prepared formulations showed first-order release kinetics with matrix diffusion mechanism of release. The formulation containing 52.06% w/w of methocel 10000 Cps, 8.75% Eudragit® L100 offered the required release rate according to USP Pharmacopoeial guidelines. The combination of hydrophilic and hydrophobic polymers can effectively control the drug release for freely water-soluble drugs in case of extended release formulations which are the upcoming dosage forms for patient compliance in all aspects.

9. Factors controlling alkalisalt deposition in recovery boiler- release mechanisms

McKeough, P.; Kylloenen, H.; Kurkela, M. [VTT Energy, Espoo (Finland). Process Technology Group

1996-12-01

As part of a cooperative effort to develop a model to describe the behaviour of inorganic compounds in kraft recovery boilers, an experimental investigation of the release of sulphur during black liquor pyrolysis has been undertaken. Previous to these studies, the mechanisms of sulphur release and the reasons for the observed effects of process conditions on sulphur release were very poorly understood. On the basis of the experimental results, the main reactions leading to sulphur release have been elucidated with a fair degree of certainty. Logical explanations for the variations of sulphur release with temperature and with liquor solids content have been proposed. The influence of pressure has been investigated in order to gain insights into the effects of mass transfer on the sulphur-release rate. In the near future, the research will be aimed at generating the kinetic data necessary for modelling the release of sulphur in the recovery furnace. (author)

10. Radionuclide release calculations for SAR-08

Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))

2008-04-15

Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

11. Passive migration barriers using slow release oxygen compounds

Norris, R.D. [Eckenfelder, Inc., Nashville, TN (United States); Johnson, J. [GRAM, Inc., Albuquerque, NM (United States); Odencrantz, J. [TRI-S Environmental Corp., Newport Beach, CA (United States)] [and others

1995-12-31

This paper describes passive barriers for controlling downgradient plume migration in contaminated aquifers. Numerous field studies using migration barriers to control benzene, toluene, ethylbenzene, and xylene (BTEX) plumes are briefly summarized. The barriers consist of a patented oxygen release compound placed in a row of wells transecting a BTEX plume. Oxygen is slowly released to the saturated zone, thus enhancing natural biodegradation. Migration is controlled by matching the oxygen release rate to the flux and oxygen demand of the dissolved contaminants.

12. Carpal tunnel release

Larsen, Morten Bo; Sørensen, A I; Crone, K L;

2013-01-01

A single-blind, randomized, controlled trial was done to compare the results of carpal tunnel release using classic incision, short incision, or endoscopic technique. In total, 90 consecutive cases were included. Follow-up was 24 weeks. We found a significantly shorter sick leave in the endoscopi...... incision could be found. There were no serious complications in either group. The results indicate that the endoscopic procedure is safe and has the benefit of faster rehabilitation and return to work....

13. Cryogenic hydrogen release research.

LaFleur, Angela Christine [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-12-01

The objective of this project was to devolop a plan for modifying the Turbulent Combustion Laboratory (TCL) with the necessary infrastructure to produce a cold (near liquid temperature) hydrogen jet. The necessary infrastructure has been specified and laboratory modifications are currently underway. Once complete, experiments from this platform will be used to develop and validate models that inform codes and standards which specify protection criteria for unintended releases from liquid hydrogen storage, transport, and delivery infrastructure.

14. EIA new releases

1994-12-01

This report was prepared by the Energy Information Administration. It contains news releases on items of interest to the petroleum, coal, nuclear, electric and alternate fuels industries ranging from economic outlooks to environmental concerns. There is also a listing of reports by industry and an energy education resource listing containing sources for free or low-cost energy-related educational materials for educators and primary and secondary students.

15. Contact: Releasing the news

Pinotti, Roberto

The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

16. Design of a new type of coating for the controlled release of heparin

Hinrichs, W.L.J.; Hinrichs, W.L.J.; ten Hoopen, Hermina W.M.; Wissink, M.J.B.; Engbers, G.H.M.; Feijen, Jan

1997-01-01

Thrombus formation at the surface of blood contacting devices can be prevented by local release of heparin. Preferably, the release rate should be constant for prolonged periods of time. The minimum heparin release rate to achieve thromboresistance will be different for various applications and

17. Formulation and Evaluation of Nateglinide Sustained Release Tablets

Sridevi Gowripattapu

2016-01-01

Full Text Available The objective of the present investigation was to design suitable sustained release tablet formulation of Nateglinide by using different polymers such as hydroxy propyl methyl cellulose K15M, xanthan gum, guar gum as release rate retarding polymers. The tablets were prepared by direct compression technique. Nateglinide is used as anti diabetic drug. The objective of the treatment is to achieve hypoglycemia, by using an ideal dosage regimen. The sustained release formulation provides extend duration of action in therapeutic range without reaching toxic levels as in the case of conventional dosage forms. The real formulation trails are carried from F1 to F9 in which Drug: Polymer ratio was set as 1:9 respectively. The prepared formulations F1 to F9 were evaluated for pre and post compression characteristics, along with the in vitro dissolution Studies. It was found that the release of drug from F1, F2, and F3 gave the better release than other formulations. In these three formulations F2 showing highest release following first order kinetics. From the Higuchi plot good correlation coefficient was observed showing diffusion mechanism. From the peppas plot it was observed that the release model was non fickian anomalous. The release rate was decreased as polymer concentration increased so it shows that increase in diffusion length of polymer decreases the release rate.

18. Mechanisms of HSP72 release

Alexzander Asea

2007-04-01

Currently two mechanisms are recognized by which heat shock proteins (HSP) are released from cells; a passive release mechanism, including necrotic cell death, severe blunt trauma, surgery and following infection with lytic viruses, and an active release mechanism which involves the non classical protein release pathway. HSPs are released both as free HSP and within exosomes. This review covers recent findings on the mechanism by which stress induces the release of HSP72 into the circulation and the biological significance of circulating HSP72 to host defense against disease.

19. Triggered Release from Polymer Capsules

Esser-Kahn, Aaron P. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry; Odom, Susan A. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry; Sottos, Nancy R. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Materials Science and Engineering; White, Scott R. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Aerospace Engineering; Moore, Jeffrey S. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry

2011-07-06

Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

20. Protecting privacy in data release

Livraga, Giovanni

2015-01-01

This book presents a comprehensive approach to protecting sensitive information when large data collections are released by their owners. It addresses three key requirements of data privacy: the protection of data explicitly released, the protection of information not explicitly released but potentially vulnerable due to a release of other data, and the enforcement of owner-defined access restrictions to the released data. It is also the first book with a complete examination of how to enforce dynamic read and write access authorizations on released data, applicable to the emerging data outsou

1. Nitrogen Uptake Rate and Use Efficiency by Rice Under Different Levels of the Controlled-Release N Fertilizers（CRF） in the Nansi Lake Basin%控释肥条件下沿南四湖农田水稻吸氮特征

张晴雯; 杜春祥; 李晓伟; 李贵春; 王明

2011-01-01

氮素是水稻必需营养元素中限制植物生长和形成产量的首要因素,同时也是南四湖水体主要营养性污染物之一.通过施用树脂包膜控释尿素不同氮肥量处理大田试验,研究了南四湖流域鱼台农田控释肥条件下水稻生育期的吸氮特征.结果表明,树脂包膜控释尿素对水稻产量有明显的促进作用,但并不随施氮量的增加呈线性增长,施用中氮量337.5 kg/hm^2水平下吸氮速率和氮肥利用率最高,吸氮速率为22.48 mg/（株.d）,氮肥利用率为37.17%,均显著高于低氮和高氮的处理.控释尿素对生物学特性的影响有明显的阶段性,水稻吸氮高峰出现%The nitrogen（N） fertilizers overused or misused are the main contributors for water eutrophication of the Nansi Lake in eastern China.A field experiment with different application levels of controlled-release N fertilizer（CRF） was carried out at a rice field in the Nansi lake basin to provide information on the nitrogen uptake rate and use efficiency by rice with CRF application at different growth stages of rice.The fertilization levels for the controlled fertilizer in this study were 0,300,337.5 and 375 kg/hm2,respectively,and 375 kg/hm^2 for conventional urea（CU）.We estimated the N uptake rate in different growing season and apparent recovery of fertilizer in root,stover and grain of rice.The result showed that grain yield increased by higher N rate.However,the N uptake rate did not increase linearly with the nitrogen application amount.The highest N uptake rate was 22.48 mg/（plant·d） under the fertilization amount of 337.5 kg/hm^2 during the young panicle differentiation stage.Apparent N recovery efficiency for CU with traditional application amount of 375 kg/hm2 was 21.86%.Apparent N recovery efficiency for CRF with application amount of 337.5 kg/hm2was highest with 37.17%.Based on the statistical data,with CU of traditional urea application amount of 375 kg/hm^2,nitrogen

2. Electrochemical Corrosion Studies for Modeling Metallic Waste Form Release Rates

Poineau, Frederic [Univ. of Nevada, Las Vegas, NV (United States); Tamalis, Dimitri [Florida Memorial Univ., Miami Gardens, FL (United States)

2016-08-01

The isotope 99Tc is an important fission product generated from nuclear power production. Because of its long half-life (t1/2 = 2.13 ∙ 105 years) and beta-radiotoxicity (β⁻ = 292 keV), it is a major concern in the long-term management of spent nuclear fuel. In the spent nuclear fuel, Tc is present as an alloy with Mo, Ru, Rh, and Pd called the epsilon-phase, the relative amount of which increases with fuel burn-up. In some separation schemes for spent nuclear fuel, Tc would be separated from the spent fuel and disposed of in a durable waste form. Technetium waste forms under consideration include metallic alloys, oxide ceramics and borosilicate glass. In the development of a metallic waste form, after separation from the spent fuel, Tc would be converted to the metal, incorporated into an alloy and the resulting waste form stored in a repository. Metallic alloys under consideration include Tc–Zr alloys, Tc–stainless steel alloys and Tc–Inconel alloys (Inconel is an alloy of Ni, Cr and iron which is resistant to corrosion). To predict the long-term behavior of the metallic Tc waste form, understanding the corrosion properties of Tc metal and Tc alloys in various chemical environments is needed, but efforts to model the behavior of Tc metallic alloys are limited. One parameter that should also be considered in predicting the long-term behavior of the Tc waste form is the ingrowth of stable Ru that occurs from the radioactive decay of 99Tc (99Tc → 99Ru + β⁻). After a geological period of time, significant amounts of Ru will be present in the Tc and may affect its corrosion properties. Studying the effect of Ru on the corrosion behavior of Tc is also of importance. In this context, we studied the electrochemical behavior of Tc metal, Tc-Ni alloys (to model Tc-Inconel alloy) and Tc-Ru alloys in acidic media. The study of Tc-U alloys has also been performed in order to better understand the nature of Tc in metallic spent fuel. Computational modeling and simulations were performed to shed light on experimental results and explain structural and kinetics trends.

3. Interfacial Fast Release Layer in Monodisperse Poly (lactic-co-glycolic acid) Microspheres Accelerates the Drug Release.

Wu, Jun; Zhao, Xiaoli; Yeung, Kelvin W K; To, Michael K T

2016-01-01

Understanding microstructural evolutions of drug delivery devices during drug release process is essential for revealing the drug release mechanisms and controlling the drug release profiles. In this study, monodisperse poly (lactic-co-glycolic acid) microspheres in different diameters were fabricated by microfluidics in order to find out the relationships between the microstructural evolutions and the drug release profiles. It was found that poly (lactic-co-glycolic acid) microspheres underwent significant size expansion which took place from the periphery to the center, resulting in the formation of interfacial fast release layers. At the same time, inner pores were created and the diffusion rate was increased so that the early stage drug release was accelerated. Due to the different expansion rates, small poly (lactic-co-glycolic acid) microspheres tendered to follow homogeneous drug release while large poly (lactic-co-glycolic acid) microspheres tendered to follow heterogeneous drug release. This study suggests that the size expansion and the occurrence of interfacial fast release layer were important mechanisms for early stage drug release of poly (lactic-co-glycolic acid) microspheres.

4. Active compounds release from semisolid dosage forms.

Olejnik, Anna; Goscianska, Joanna; Nowak, Izabela

2012-11-01

The aim of this paper is to review all the aspects of the in vitro release testing (IVRT) from semisolid dosage forms. Although none of the official dissolution methods has been specified for use with semisolid dosage forms, their utility for assessing release rates of drugs from semisolid dosage forms has become a topic of considerable interest. One can expect to overcome such complexity in the future, when the official "Topical and Transdermal Drug Products-Product Performance Tests" will be published in an issue of the Pharmacopeial Forum. Many factors such as type of the dissolution medium, membrane, temperature, and speed have an influence on the mechanism and kinetics of the release testing from gels, creams, and ointments; therefore, those parameters have been widely discussed.

5. Allegheny County Toxics Release Inventory

Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Toxics Release Inventory (TRI) data provides information about toxic substances released into the environment or managed through recycling, energy recovery, and...

6. Modifying sorbents in controlled release formulations to prevent herbicides pollution.

Flores Céspedes, F; Villafranca Sánchez, M; Pérez García, S; Fernández Pérez, M

2007-10-01

The herbicides chloridazon and metribuzin, identified as groundwater pollutants, were incorporated in alginate-based granules to obtain controlled release properties. In this research the effect of incorporation of sorbents such as bentonite, anthracite and activated carbon in alginate basic formulation were not only studied on encapsulation efficiency but also on the release rate of herbicides which was studied using water release kinetic tests. In addition, sorption studies of herbicides with bentonite, anthracite and activated carbon were made. The kinetic experiments of chloridazon and metribuzin release in water have shown that the release rate is higher in metribuzin systems than in those prepared with chloridazon, which has lower water solubility. Besides, it can be deduced that the use of sorbents reduces the release rate of the chloridazon and metribuzin in comparison to the technical product and to the alginate formulation without sorbents. The highest decrease in release rate corresponds to the formulations prepared with activated carbon as a sorbent. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, T(50), were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the herbicide release data, the release of chloridazon and metribuzin from the various formulations into water is controlled by a diffusion mechanism. Sorption capacity of the sorbents for chloridazon and metribuzin, ranging from 0.53mgkg(-1) for the metribuzin sorption on bentonite to 2.03x10(5)mgkg(-1) for the sorption of chloridazon on the activated carbon, was the most important factor modulating the herbicide release.

7. Heat release mechanism of energetics

Kubota, N. [Third Research Center, Technical Research and development Institute (Japan)

1996-12-31

Determination of the heat release mechanism of energetic materials is a major subject of combustion study. In order to elucidate the combustion process of various types of energetic materials a generalized combustion wave structure was proposed and the heat release process was discussed. The heat release process was significantly different between the physical structures of the materials: homogeneous and heterogeneous materials. The thermal structure of an azide polymer was evaluated to demonstrate the heat release mechanism. (author) 6 refs.

8. 76 FR 46603 - Security Ratings

2011-08-03

... forms without regard to the size of their public float or the rating of debt securities being offered...: Blair Petrillo, Special Counsel in the Office of Rulemaking, Division of Corporation Finance, at (202... Nationally Recognized Statistical Rating Organizations, Release No. 33-9069 (Oct. 5, 2009) . Public...

9. Environmental Releases for Calendar Year 2001

DYEKMAN, D L

2002-08-01

This report fulfills the annual reporting requirements of US Department of Energy (DOE) Order 5400.1, General Environmental Protection Program. The report contains tabular data summaries on air emissions and liquid effluents released to the environment as well as nonroutine releases during calendar year (CY) 2001. These releases, bearing radioactive and hazardous substances, were from Bechtel Hanford, Inc. (BHI), CH2M HILL Hanford Group, Inc. (CHG), and Fluor Hanford (FH) managed facilities and activities. These data were obtained from direct sampling and analysis and from estimates based upon approved release factors. This report further serves as a supplemental resource to the Hanford Site Environmental Report (HSER PNNL-13910), published by the Pacific Northwest National Laboratory. HSER includes a yearly accounting of the impacts on the surrounding populace and environment from major activities at the Hanford Site. HSER also summarizes the regulatory compliance status of the Hanford Site. Tables ES-1 through ES-5 display comprehensive data summaries of CY2001 air emission and liquid effluent releases. The data displayed in these tables compiles the following: Radionuclide air emissions; Nonradioactive air emissions; Radionuclides in liquid effluents discharged to ground; Total volumes and flow rates of radioactive liquid effluents discharged to ground; and Radionuclides discharged to the Columbia River.

10. The Effects of Metoprolol Sustained-released Tablets on Heart Rates of Patients with Acute Myocardial Infarction%琥珀酸美托洛尔缓释片治疗急性心肌梗死的疗效观察

刘庆

2013-01-01

Objective To observe the clinical effects of the heart rates of patients with acute myocardial infarction after taking metoprolol succinate sustained-release tablets in the early phase. Methods 125 acute myocardial infarction patients were randomly assigned to group A(n=63) and group B(n=62).Group A were treated with metoprolol succinate sustained-release tablets 23.75-90mg/d,once daily, Group B were treated with metoprolol tartrate tablets 23.75-90mg/d.Besides,both group was remedied on the basis of conventional treatment.And to observe the impact in heart rate、arrhythmia、cardiogenic shock、death and stenocardia after four-week’s treatment, P<0.05. Result The servation group had advantage in improving cardiac variation,reducing cardiogenic shock,sudden death and infarct size and relieving pain than matched group. Conclusion The early use of metoprolol succinate sustained-release tablets in the AMI will improve myocardial infarction prognosis.%　　目的观察早期应用琥珀酸美托洛尔缓释片治疗急性心肌梗死的临床疗效。方法选择急性心肌梗死125例，随机分为两组，琥珀酸美托洛尔缓释片组63例和酒石酸美托洛尔组62例，前者在常规治疗基础上予琥珀酸美托洛尔缓释片23.75～90mg口服，一次/日，后者在常规治疗基础上给酒石酸美托洛尔片12.5～75mg口服，2次/日，治疗4周，观察其对心率，心律失常，心源性休克，死亡及心绞痛的影响，P＜0.05。结果观察组在提高心率变异，降低心源性休克，猝死，缩小梗死面积，缓解疼痛方面均优于对照组。结论急性心肌梗死早期使用美托洛尔缓释片可改善心梗预后。

11. PREPARATION AND RELEASE RATE OF A LEVONORGESTREL-RELEASING INTRAUTERINE DEVICE

LINWu; JINGZhao-Ying; ZHUGeng-Geng

1989-01-01

A key-shaped lcvonorgcstrcl-rclcasing intrauterine device ( LNG-IUD ) was designed and fabricated. The IUD with a hollow vcrtlcal arm was made of modified ethylene-vinyl acetate copolymcr ( EVA ). The LNG paste was cncapsulcd in the vertical arm to

12. Is bioexsiccation releasing dioxins?

Benfenati, E.; Mariani, G.; Lodi, M.; Reitano, G.; Fanelli, R. [' ' Mario Negri' ' Institute for Pharmacological Research, Milan (Italy)

2004-09-15

Bioexsiccation is a relatively new process to treat urban solid wastes. We studied the possible release of dioxins from this process, measuring dioxin concentration in the emissions from a bioexsiccation plant. As a comparison, we measured atmospheric levels nearby the plant. The biofilter treating gaseous emissions was also evaluated to assess its efficiency. Dioxin concentrations in the biofilter effluent were lower than both those before the biofilter and the nearby atmosphere. In the last years the management and treatment of solid urban wastes produced some improved processes, in a general attempt to cope with the problem of the huge amount of wastes produced by the modern society. Bio-exsiccation of waste aims at affording a much more biologically inert and manageable material compared to the original waste. In this process the urban solid waste is kept under an air stream for about two weeks. The waste undergoes biological transformation, due to fermentation, which produces an increase of the temperature up to 60-70 C. At the end of the process the weight waste is typically reduced by one third, due to the loss of water and to the degradation of putrescible compounds. Since this is a relatively new industrial process, we studied the possible release of dioxins in the atmospheric emissions of the bioexsiccation plant.

13. Building an Efficient Model for Afterburn Energy Release

Alves, S; Kuhl, A; Najjar, F; Tringe, J; McMichael, L; Glascoe, L

2012-02-03

Many explosives will release additional energy after detonation as the detonation products mix with the ambient environment. This additional energy release, referred to as afterburn, is due to combustion of undetonated fuel with ambient oxygen. While the detonation energy release occurs on a time scale of microseconds, the afterburn energy release occurs on a time scale of milliseconds with a potentially varying energy release rate depending upon the local temperature and pressure. This afterburn energy release is not accounted for in typical equations of state, such as the Jones-Wilkins-Lee (JWL) model, used for modeling the detonation of explosives. Here we construct a straightforward and efficient approach, based on experiments and theory, to account for this additional energy release in a way that is tractable for large finite element fluid-structure problems. Barometric calorimeter experiments have been executed in both nitrogen and air environments to investigate the characteristics of afterburn for C-4 and other materials. These tests, which provide pressure time histories, along with theoretical and analytical solutions provide an engineering basis for modeling afterburn with numerical hydrocodes. It is toward this end that we have constructed a modified JWL equation of state to account for afterburn effects on the response of structures to blast. The modified equation of state includes a two phase afterburn energy release to represent variations in the energy release rate and an afterburn energy cutoff to account for partial reaction of the undetonated fuel.

14. Comparison of sequential drug release in vitro and in vivo.

Sundararaj, Sharath C; Al-Sabbagh, Mohanad; Rabek, Cheryl L; Dziubla, Thomas D; Thomas, Mark V; Puleo, David A

2016-10-01

Development of drug-delivery devices typically involves characterizing in vitro release performance with the inherent assumption that this will closely approximate in vivo performance. Yet, as delivery devices become more complex, for instance with a sequential drug release pattern, it is important to confirm that in vivo properties correlate with the expected "programming" achieved in vitro. In this work, a systematic comparison between in vitro and in vivo biomaterial erosion and sequential release was performed for a multilayered association polymer system comprising cellulose acetate phthalate and Pluronic F-127. After assessing the materials during incubation in phosphate-buffered saline, devices were implanted supracalvarially in rats. Devices with two different doses and with different erosion rates were harvested at increasing times post-implantation, and the in vivo thickness loss, mass loss, and the drug release profiles were compared with their in vitro counterparts. The sequential release of four different drugs observed in vitro was successfully translated to in vivo conditions. Results suggest, however, that the total erosion time of the devices was longer and that release rates of the four drugs were different, with drugs initially released more quickly and then more slowly in vivo. Many comparative studies of in vitro and in vivo drug release from biodegradable polymers involved a single drug, whereas this research demonstrated that sequential release of four drugs can be maintained following implantation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1302-1310, 2016.

15. Influence of alcohol on the release of tramadol from 24-h controlled-release formulations during in vitro dissolution experiments.

Traynor, M J; Brown, M B; Pannala, A; Beck, P; Martin, G P

2008-08-01

Recent warnings by regulatory bodies and a product recall by the FDA have generated much interest in the area of dose dumping from controlled-release opioid analgesic formulations when coingested with alcohol. It was the aim of this study to address this issue and in doing so, gain understanding on how alcohol-induced effects may be avoided. In this study, tramadol release from Ultram ER tablets and T-long capsules was significantly increased in the presence of ethanol. Conversely, a decrease in the rate of tramadol release was seen from Tridural extended-release tablets in the presence of alcohol.

16. Innovation and evaluation of refractive index (RI) method of rapid determination for urea release rate of coated urea%折光率法在包膜尿素养分释放快速测定中的校验与改进

喻建刚; 刘芳; 樊小林

2013-01-01

The rapid method to evaluation of controlled release fertilizer had been established in China, which included the eletrical conductivety (EC) method and the refractive index(RI) method.The RI method was only applied for polymer coated urea. The substrates of the coated ureas were organic chemicals, however, during the the incubation, the urea release could be transformed into inorganic form such as NH4+, which would influence the test accurateness of the RI method. It was possible to incubate a working curve companied with tested samples would cancellthe effect of urea form change. So 15 self-made coated ureas with different longevities were taken as samples, which were divided into three groups according to their nutrient release rates, and the samples were incubated in still pure water under the constant temperture of (25±0.5)℃with the fertilizer/water ratio of 1/5, at the same time standard concentration urea solution was incubated under the same condition to get a working curve. And the urea incubation solutions were collected after 1, 7, 14, 21, 28, 42, 56, 70, 98, 126, 154, 210, 266 days during the incubation with renewal of pure water. After that the routine determination of H2SO4 degestion method and the RI method with a working curve at the same incubation interval companied with the tested samples were applied to test nutrient release rate of the coated urea, further more the Richards equation was applied to make a nonliner analysis for each nutrient release curve and calculate the longevities of coated ureas. Finally, the results tested by different methods were used to analyse their similarities and differences and offer a more accurate and rapid determination for polymer coated urea. The results were as follows. Firstly, the EC values of a series of standard concentration urea solution increased with the incubaiton period prolonged, but urea mass concentration and their RI values always had a significant linear correlation relationship (r2≥0

17. Formulation development and release studies of indomethacin suppositories

Sah M

2008-01-01

Full Text Available Indomethacin suppositories were prepared by using water-soluble and oil soluble suppository bases, and evaluated for in vitro release by USP I and modified continuous flow through bead bed apparatus. Effect of the Tween 80 (1% and 5% was further studied on in vitro release of the medicament. Release rate was good in water-soluble suppositories bases in comparison to oil soluble suppositories bases. Release was found to be greater in modified continuous flow through bead bed apparatus. When surfactant was used in low concentration then release rate was much greater, as compared to high concentration. When stability studies were performed on the prepared indomethacin suppositories it was found that suppositories made by water-soluble base had no significant changes while suppositories prepared by oil soluble bases, had some signs of instability.

18. 琥珀酸美托洛尔缓释片和酒石酸美托洛尔片对急性心肌梗死患者心率的影响%Comparison of effects of metoprolol succinate sustained-release tablets and metoprolol tartrate tablets on heart rates of patients with acute myocardial infarction

王蛟龙; 陈莉; 齐国先

2011-01-01

目的 比较琥珀酸美托洛尔缓释片和酒石酸美托洛尔片对急性心肌梗死患者心率的影响.方法 选择急性心肌梗死患者76例,在除外应用美托洛尔禁忌后,按1:2比例随机分配到琥珀酸美托洛尔缓释片组25例和酒石酸美托洛尔片组51例.前者给予琥珀酸美托洛尔23.75 mg,日1次口服,后者给予酒石酸美托洛尔12.5 mg,日2次口服.在此基础上,两组均常规予阿司匹林、氯吡格雷、ACEI及他汀类药物治疗,分别记录用药前和用药后24、48、72 h静息状态的心率,比较用药后心率下降的程度和趋势.结果 琥珀酸美托洛尔缓释片组在用药后24、48、72 h 3个时间点的心率分别下降了0、1%、9%,次数下降了0.5次/min、1.6次/min、7.6次/min,酒石酸美托洛尔片组心率分别下降了3%、5%、6%,次数下降了3.5次/min、4.1次/min、5.7次/min.P均0.05,尚不能认为剂型和心率有交互作用.两组患者服药后72 h内,心率变化的趋势无统计学意义,P均>0.05.结论 急性心肌梗死患者应用琥珀酸美托洛尔缓释片或酒石酸美托洛尔片,72 h内心率降低的差异有统计学意义,但两组服药后72 h内,心率的降低程度差异无统计学意义,而且72 h内两组心率下降的趋势,差异也无统计学意义.%Objective To compare the heart rates of patients with acute myocardial infarction after taking metoprolol succinate sustained-release tablets or metoprolol tartrate tablets.Methods 76 acute myocardial infarction patients were randomly assigned to group A(n =25) and group B(n =51 ).Group A were treated with metoprolol succinate sustained-release tablets 23.75 mg/d,once daily,group B were treated with metoprolol tartrate tablets 12.5 mg,twice a day.Besides, both group was treated with aspirin, clopidogrel, ACEI and statin according to clinical practice.Heart rate in resting state 0,24,48,72 h after the application were recorded respectively,and the degree and trend of decrease in

19. Hydroxypropyl methylcellulose based cephalexin extended release tablets: influence of tablet formulation, hardness and storage on in vitro release kinetics.

Saravanan, Muniyandy; Sri Nataraj, Kalakonda; Ganesh, Kettavarampalayam Swaminath

2003-08-01

The object of this study was to develop hydroxypropyl methylcellulose (HPMC) based cephalexin extended release tablet, which can release the drug for six hours in predetermined rate. Twenty-one batches of cephalexin tablets were prepared by changing various physical and chemical parameters, in order to get required theoretical release profile. The influences of HPMC, microcrystalline cellulose powder (MCCP), granulation technique, wetting agent and tablet hardness on cephalexin release from HPMC based extended release tablets were studied. The formulated tablets were also characterized by physical and chemical parameters. The dissolution results showed that a higher amount of HPMC in tablet composition resulted in reduced drug release. Addition of MCCP resulted in faster drug release. Tablets prepared by dry granulation was released the drug slowly than the same prepared with a wet granulation technique. Addition of wetting agent in the tablets prepared with dry granulation technique showed slower release. An increase in tablet hardness resulted in faster drug release. Tablets prepared with a wet granulation technique and having a composition of 9.3% w/w HPMC with a hardness of 10-12 kg/cm(2) gave predicted release for 6 h. The in vitro release data was well fit in to Higuchi and Korsmeyer-Peppas model. Physical and chemical parameters of all formulated tablets were within acceptable limits. One batch among formulated twenty-one batches was successful and showed required theoretical release. The effect of storage on in vitro release and physicochemical parameters of successful batch was studied and was found to be in acceptable limits.

20. Attentional priming releases crowding.

Kristjánsson, Arni; Heimisson, Pétur Rúnar; Róbertsson, Gunnar Freyr; Whitney, David

2013-10-01

Views of natural scenes unfold over time, and objects of interest that were present a moment ago tend to remain present. While visual crowding places a fundamental limit on object recognition in cluttered scenes, most studies of crowding have suffered from the limitation that they typically involved static scenes. The role of temporal continuity in crowding has therefore been unaddressed. We investigated intertrial effects upon crowding in visual scenes, showing that crowding is considerably diminished when objects remain constant on consecutive visual search trials. Repetition of both the target and distractors decreases the critical distance for crowding from flankers. More generally, our results show how object continuity through between-trial priming releases objects that would otherwise be unidentifiable due to crowding. Crowding, although it is a significant bottleneck on object recognition, can be mitigated by statistically likely temporal continuity of the objects. Crowding therefore depends not only on what is momentarily present, but also on what was previously attended.

1. Mechanisms of Methane Release From Lake Sediments

Shiba, Jacob

2015-01-01

Methane is a powerful greenhouse gas that can be produced in bottom sediments of lakes and reservoirs and released through ebullition and other properties. Many studies have quantified ebullition rates, however, the detailed mechanisms remain incompletely understood. This study was undertaken to better understand, through in situ and laboratory measurements, the mechanisms of gas ebullition from lake sediment. Four sites on Lake Elsinore, CA with different properties were evaluated through th...

2. Chlorhexidine-releasing methacrylate dental composite materials.

Leung, Danny; Spratt, David A; Pratten, Jonathan; Gulabivala, Kishor; Mordan, Nicola J; Young, Anne M

2005-12-01

Light curable antibacterial, dental composite restoration materials, consisting of 80 wt% of a strontium fluoroaluminosilicate glass dispersed in methacrylate monomers have been produced. The monomers contained 40-100 wt% of a 10 wt% chlorhexidine diacetate (CHXA) in hydroxyethylmethacrylate (HEMA) solution and 60-0 wt% of a 50/50 mix of urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA). On raising HEMA content, light cure polymerisation rates decreased. Conversely, water sorption induced swelling and rates of diffusion controlled CHXA release from the set materials increased. Experimental composites with 50 and 90 wt% of the CHXA in HEMA solution in the monomer were shown, within a constant depth film fermentor (CDFF), to have slower rates of biofilm growth on their surfaces between 1 and 7 days than the commercial dental composite Z250 or fluoride-releasing dental cements, Fuji II LC and Fuji IX. When an excavated bovine dentine cylinder re-filled with Z250 was placed for 10 weeks in the CDFF, both bacteria and polymers from the artificial saliva penetrated between the material and dentine. With the 50 wt% experimental HEMA/CHXA formulation, this bacterial microleakage was substantially reduced. Polymer leakage, however, still occurred. Both polymer and bacterial microleakage were prevented with a 90 wt% HEMA/CHXA restoration in the bovine dentine due to swelling compensation for polymerisation shrinkage in combination with antibacterial release.

3. Hydrogen Release Studies of Alkali Metal Amidoboranes

Luedtke, Avery T.; Autrey, Thomas

2010-04-19

A series of metal amido boranes LiNH2BH3 (LAB), NaNH2BH3 (SAB), LiNH(Me)BH3 (LMAB), NaNH(Me)BH3 (SMAB), KNH(Me)BH3 (PMAB), and KNH(tBu)BH3 (PBAB) were synthesized, by solution phase methods, and the thermal release of H2 in the solid state was studied. Based on the observed trends in reaction rates of H > Me > tBu and the kinetic isotope effect, the mechanism of hydrogen release from MAB compounds was found to proceed through a bimolecular mechanism involving the intermediacy of a MH (M = Li, Na, or K). The mechanism of hydrogen release from metal amidoboranes, a metal ion assisted hydride transfer, is very different than the mechanism of hydrogen release from the parent compound ammonia borane (AB). The non-volatile products formed from MAB’s are significantly different than the products formed after hydrogen release from AB. The boron containing resulting from the release of one equivalent of hydrogen from the metal amidoboranes were characterized by MAS 11B NMR spectroscopy and found to contain both BH3 and sp2 hybridized BH groups, consistent with a general structural feature MN(R)=BHN(R)MBH3. This work was funded by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy as part of the Chemical Hydrogen Storage CoE at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the U.S. DOE by Battelle. MAS NMR studies were performed using EMSL, a national scientific user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research located at PNNL.

4. Optogenetic control of ATP release

Lewis, Matthew A.; Joshi, Bipin; Gu, Ling; Feranchak, Andrew; Mohanty, Samarendra K.

2013-03-01

Controlled release of ATP can be used for understanding extracellular purinergic signaling. While coarse mechanical forces and hypotonic stimulation have been utilized in the past to initiate ATP release from cells, these methods are neither spatially accurate nor temporally precise. Further, these methods cannot be utilized in a highly effective cell-specific manner. To mitigate the uncertainties regarding cellular-specificity and spatio-temporal release of ATP, we herein demonstrate use of optogenetics for ATP release. ATP release in response to optogenetic stimulation was monitored by Luciferin-Luciferase assay (North American firefly, photinus pyralis) using luminometer as well as mesoscopic bioluminescence imaging. Our result demonstrates repetitive release of ATP subsequent to optogenetic stimulation. It is thus feasible that purinergic signaling can be directly detected via imaging if the stimulus can be confined to single cell or in a spatially-defined group of cells. This study opens up new avenue to interrogate the mechanisms of purinergic signaling.

5. Cobalt release from inexpensive jewellery

Thyssen, Jacob Pontoppidan; Jellesen, Morten Stendahl; Menné, Torkil

2010-01-01

Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items....... Microstructural characterization was made using scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS). Results: Cobalt release was found in 4 (1.1%) of 354 items. All these had a dark appearance. SEM/EDS was performed on the four dark appearing items which showed tin-cobalt plating on these....... Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future...

6. COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

1999-10-18

The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

7. Controlled release implants based on cast lipid blends.

Kreye, F; Siepmann, F; Zimmer, A; Willart, J F; Descamps, M; Siepmann, J

2011-05-18

The aim of this study was to use lipid:lipid blends as matrix formers in controlled release implants. The systems were prepared by melting and casting and thoroughly characterized before and after exposure to the release medium. Based on the experimental results, a mechanistic realistic mathematical model was used to get further insight into the underlying drug release mechanisms. Importantly, broad spectra of drug release patterns could be obtained by simply varying the lipid:lipid blend ratio in implants based on Precirol ATO 5 (glyceryl palmitostearate):Dynasan 120 (hardened soybean oil) mixtures loaded with propranolol hydrochloride. Release periods ranging from a few days up to several months could be provided. Interestingly, the drug release rate monotonically decreased with increasing Dynasan 120 content, except for implants containing about 20-25% Precirol, which exhibited surprisingly high release rates. This could be attributed to the incomplete miscibility of the two lipids at these blend ratios: DSC thermograms showed phase separation in these systems. This is likely to cause differences in the implants' microstructure, which determines the mobility of water and dissolved drug as well as the mechanical stability of the systems. Purely diffusion controlled drug release was only observed at Precirol ATO 5 contents around 5-10%. In all other cases, limited drug solubility effects or matrix former erosion are also expected to play a major role. Thus, lipid:lipid blends are very interesting matrix formers in controlled release implants. However, care must be taken with respect to the mutual miscibility of the compounds: in case of phase separation, surprisingly high drug release rates might be observed.

8. Sulphate release from building rubble of WWII

Mekiffer, Beate; Wessolek, Gerd; Vogeler, Iris; Brettholle, Mareike

2010-05-01

Sulphate concentration in the upper aquifer of Berlin, Germany is increasing continuously since 40 years. In downtown Berlin they particular exceed the precaution values of drinking water ordinance. We assume that the main source of sulphate in the groundwater is technogenic material, which is part of building rubble from WW II bombing. Nearly 115 Mio t of this material have been deposited in Berlin. Our aim is, ­ to identify rubble components which contain S and to quantify the S-pool of this material ­ to identify factors, influencing the release of SO4 and ­ to predict sulphate release from building rubble of WW II We analyzed total and water soluble S of various components and the fine earth fraction of the soils containing the rubble. We investigated the influence of physical and chemical parameters on the release of SO4 using unsaturated column experiments (With an automatic percolation system). Thereby, the particle size, the flow rate and the pH of the solution has been varied. Among the components, slag shows the highest total S-contents of up to 0,7% . Lignite Coal-ashes from Lusatia, Germany are also rich in SO4. The total S of brick varies between 0,01% and 0,3%. Mortar shows S-Values between 0,08 and 0,12%. In 75% of all samples show total S of less than 0,14%. There was no significant correlation between total S-amount and water-soluble SO4, which is caused by different chemical compounds in the samples. In the percolation experiments technogenic components with grain size <2mm cause a higher density, resulting in a lower percolation velocity. The concentration of ions in the according leachate is higher than in the leachate of coarse fraction (2 - 20mm). Gypsum-rich material (10%) released constant SO4 -concentration over the whole experiment. Slag-rich material released high initial SO4-concentrations which then fastly decreased. We concluded, that the kind of technogenic component and its grain size strongly influences the release of SO4 to the

9. Preparation and evaluation of controlled release tablets of carvedilol

Varahala Setti M

2009-01-01

Full Text Available The objective of the present investigation is to design and evaluate controlled release tablets of carvedilol, employing synthetic polymers like polyethylene oxides, of different molecular weights as release retarding materials and to select the optimized formulation based on the pharmacokinetics of carvedilol. Matrix tablets each containing 80 mg of carvedilol were formulated employing PEO N60 K, PEO 301, and PEO 303 as release-retarding polymers and β Cyclodextrin and HP β cyclodextrin as release modulators from the matrix. Carvedilol release from the formulated tablets was very slow. Hence the release was modulated with the use of cyclodextrins. The dissolution from the matrix tablets was spread over more than 24 hours and depended on the type of polymer, its concentration and the type of cyclodextrin used. All the matrix tablets prepared using polyethylene oxides showed very good controlled release over more than 24 hours. The matrix tablets prepared using HP β cyclodextrin showed a higher dissolution rate and gave a dissolution profile that was comparable to the theoretical sustained release needed for once-a-day administration of carvedilol. The drug release mechanism from the matrix tablets was found to be quasi Fickian mechanism.

10. Assembly of bio-nanoparticles for double controlled drug release.

Wei Huang

Full Text Available A critical limiting factor of chemotherapy is the unacceptably high toxicity. The use of nanoparticle based drug carriers has significantly reduced the side effects and facilitated the delivery of drugs. Source of the remaining side effect includes (1 the broad final in vivo distribution of the administrated nanoparticles, and (2 strong basal drug release from nanoparticles before they could reach the tumor. Despite the advances in pH-triggered release, undesirable basal drug release has been a constant challenge under in vivo conditions. In this study, functionalized single walled carbon nanohorn supported immunoliposomes were assembled for paclitaxel delivery. The immunoliposomes were formulated with polyethylene glycol, thermal stable and pH sensitive phospholipids. Each nanohorn was found to be encapsulated within one immunoliposome. Results showed a highly pH dependent release of paclitaxel in the presence of serum at body temperature with minimal basal release under physiological conditions. Upon acidification, paclitaxel was released at a steady rate over 30 days with a cumulative release of 90% of the loaded drug. The drug release results proved our hypothesized double controlled release mechanism from the nanoparticles. Other results showed the nanoparticles have doubled loading capacity compared to that of traditional liposomes and higher affinity to breast cancer cells overexpressing Her2 receptors. Internalized nanoparticles were found in lysosomes.

11. A biokinetic model for nickel released from cardiovascular devices.

Saylor, David M; Adidharma, Lingga; Fisher, Jeffrey W; Brown, Ronald P

2016-10-01

Many alloys used in cardiovascular device applications contain high levels of nickel, which if released in sufficient quantities, can lead to adverse health effects. While nickel release from these devices is typically characterized through the use of in-vitro immersion tests, it is unclear if the rate at which nickel is released from a device during in-vitro testing is representative of the release rate following implantation in the body. To address this uncertainty, we have developed a novel biokinetic model that combines a traditional toxicokinetic compartment model with a physics-based model to estimate nickel release from an implanted device. This model links the rate of in-vitro nickel release from a cardiovascular device to serum nickel concentrations, an easily measured endpoint, to estimate the rate and extent of in-vivo nickel release from an implanted device. The model was initially parameterized using data in the literature on in-vitro nickel release from a nickel-containing alloy (nitinol) and baseline serum nickel levels in humans. The results of this first step were then used to validate specific components of the model. The remaining unknown quantities were fit using serum values reported in patients following implantation with nitinol atrial occluder devices. The model is not only consistent with levels of nickel in serum and urine of patients following treatment with the atrial occluders, but also the optimized parameters in the model were all physiologically plausible. The congruity of the model with available data suggests that it can provide a framework to interpret nickel biomonitoring data and use data from in-vitro nickel immersion tests to estimate in-vivo nickel release from implanted cardiovascular devices.

12. In vitro release of theophylline from poly(lactic acid) sustained-release pellets prepared by direct compression.

1998-06-01

Poly(L-lactic acid), (L-PLA) pellets containing theophylline as a model drug were prepared with increasing bovine serum albumin (BSA) load of 10, 20, 30, 40, or 50% by direct compression. The drug release from pellets was studied in phosphate buffered saline (PBS, pH 7.4) at 37 degrees C. The annealing effect on theophylline release from pellets was also studied at 20, 30, 60, and 80 degrees C. In all cases, release kinetics followed the Higuchian mechanism with an initial burst effect followed by sustained release of theophylline during the experimental period. Increasing BSA load resulted in a linear increase in Higuchian release rates presumably because of the hydrophilic nature of BSA. Furthermore, BSA did not interact chemically with the polymer matrix and was held physically by the dense polymer matrix. However, drug release decreased with an increase in annealing temperature. Release of theophylline was higher from PLA-BSA combination pellets compared to PLA pellets at temperatures below the glass transition temperature (Tg) of the polymer and lower for temperatures above Tg. The temperature effect on drug release may be attributed to both the reduction of core solubility in the bulk phase and the lowering of diffusibility of the polymeric membrane. No drug-polymer interactions or polymer degradation was observed within the experimental setup when studied by differential scanning calorimetry (DSC), infrared (FTIR) spectroscopy, and gravimetric methods. DSC studies of pellets showed no hints of microstructural changes (crystallinity) of the polymers. In our experiments, theophylline was released primarily by leaching through channels and not by polymer degradation. The release rate was dependent on BSA loading and annealing. It may be concluded that PLA pellets can be fabricated suitably using BSA and annealing to design sustained-release preparations of water-soluble drugs.

13. CONTROLLED-RELEASE OF PARACETAMOL FROM AMYLODEXTRIN TABLETS - IN-VITRO AND IN-VIVO RESULTS

VANDERVEEN, J; EISSENS, AC; LERK, CF

1994-01-01

Amylodextrin is a suitable excipient for the design of solid controlled-release systems. The release of paracetamol from tablets containing 30% drug and 70% amylodextrin was studied in vitro and in vivo. In vitro dissolution profiles showed almost-constant drug release rates during 8 hr, when measur

14. Modeling controlled nutrient release from a population of polymer coated fertilizers: statistically based model for diffusion release.

Shaviv, Avi; Raban, Smadar; Zaidel, Elina

2003-05-15

A statistically based model for describing the release from a population of polymer coated controlled release fertilizer (CRF) granules by the diffusion mechanism was constructed. The model is based on a mathematical-mechanistic description of the release from a single granule of a coated CRF accounting for its complex and nonlinear nature. The large variation within populations of coated CRFs poses the need for a statistically based approach to integrate over the release from the individual granules within a given population for which the distribution and range of granule radii and coating thickness are known. The model was constructed and verified using experimentally determined parameters and release curves of polymer-coated CRFs. A sensitivity analysis indicated the importance of water permeability in controlling the lag period and that of solute permeability in governing the rate of linear release and the total duration of the release. Increasing the mean values of normally distributed granule radii or coating thickness, increases the lag period and the period of linear release. The variation of radii and coating thickness, within realistic ranges, affects the release only when the standard deviation is very large or when water permeability is reduced without affecting solute permeability. The model provides an effective tool for designing and improving agronomic and environmental effectiveness of polymer-coated CRFs.

15. Press-coating of immediate release powders onto coated controlled release tablets with adhesives.

Waterman, Kenneth C; Fergione, Michael B

2003-05-20

A novel adhesive coating was developed that allows even small quantities of immediate-release (IR) powders to be press-coated onto controlled-release (CR), coated dosage forms without damaging the CR coating. The process was exemplified using a pseudoephedrine osmotic tablet (asymmetric membrane technology, AMT) where a powder weighing less than 25% of the core was pressed onto the osmotic tablet providing a final combination tablet with low friability. The dosage form with the adhesive plus the press-coated powder showed comparable sustained drug release rates to the untreated dosage form after an initial 2-h lag. The adhesive layer consisted of an approximately 100- microm coating of Eudragit RL, polyethylene glycol (PEG) and triethyl citrate (TEC) at a ratio of 5:3:1.2. This coating provides a practical balance between handleability before press-coating and good adhesion.

Orabi, Momen

2017-03-01

One of the main factors that affect the uncertainty in calculating the gamma-radiation absorbed dose rate inside a room is the variation in the degree of secular equilibrium of the considered radioactive series. A component of this factor, considered in this paper, is the release of radon (Rn) from building materials to the living space of the room. This release takes place through different steps. These steps are represented and mathematically formulated. The diffusion of radon inside the material is described by Fick's second law. Some of the factors affecting the radon release rate (e.g. covering walls, moisture, structure of the building materials, etc.) are discussed. This scheme is used to study the impact of radon release on the gamma-radiation absorbed dose rate inside a room. The investigation is carried out by exploiting the MCNP simulation software. Different building materials are considered with different radon release rates. Special care is given to Rn due to its relatively higher half-life and higher indoor concentration than the other radon isotopes. The results of the presented model show that the radon release is of a significant impact in some building materials.

17. Workload Control with Continuous Release

Phan, B. S. Nguyen; Land, M. J.; Gaalman, G. J. C.

2009-01-01

Workload Control (WLC) is a production planning and control concept which is suitable for the needs of make-to-order job shops. Release decisions based on the workload norms form the core of the concept. This paper develops continuous time WLC release variants and investigates their due date

18. Press Oil Final Release Survey

Whicker, Jeffrey Jay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-05-11

There are forty-eight 55 gallon barrels filled with hydraulic oil that are candidates for release and recycle. This oil needs to be characterized prior to release. Principles of sampling as provided in MARSAME/MARSSIM approaches were used as guidance for sampling.

19. PREPARATION AND EVALUATION OF SUSTAINED RELEASE MICROSPHERE OF NORFLOXACIN USING SODIUM ALGINATE

Raja Chakraverty

2012-01-01

Full Text Available Oral controlled drug delivery systems represent the most popular form of sustained drug delivery systems for the obvious advantages of oral route of drug administration. Such systems release the drug with constant or variable release rates. The oral controlled release systems shows a typical pattern of drug release in which the drug concentration is maintained in the therapeutic window for a prolonged period of time (sustained release, thereby ensuring sustained therapeutic action. They are used as single dosage form. Present work involves preparation and evaluation of sustained release of microspheres of Norfloxacin employing sodium alginate as natural polymer. The technique employed for microencapsulation of the drug is ionotropic gelation.

20. Sucrose release from polysaccharide gels.

Nishinari, Katsuyoshi; Fang, Yapeng

2016-05-18

Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed.

1. Dry release of suspended nanostructures

Forsén, Esko Sebastian; Davis, Zachary James; Dong, M.;

2004-01-01

A dry release method for fabrication of suspended nanostructures is presented. The technique has been combined with an anti-stiction treatment for fabrication of nanocantilever based nanoelectromechanical systems (NEMS). The process combines a dry release method, using a supporting layer of photo......A dry release method for fabrication of suspended nanostructures is presented. The technique has been combined with an anti-stiction treatment for fabrication of nanocantilever based nanoelectromechanical systems (NEMS). The process combines a dry release method, using a supporting layer......, the technique enables long time storage and transportation of produced devices without the risk of stiction. By combining the dry release method with a plasma deposited anti-stiction coating both fabrication induced stiction, which is mainly caused by capillary forces originating from the dehydration...

2. Evaporation release behavior of volatile fission products from liquid sodium pool to the inert cover gas

Nakagiri, T.; Miyahara, S. [Oarai Engineering Center, Power Reactor and Nuclear Fuel Development Corp., Oaraimachi, Ibaraki (Japan)

1996-12-01

In fuel failure of sodium cooled fast breeder reactors, released volatile fission products (VFPs) such as iodine and cesium from the fuel will be dissolved into the liquid sodium coolant and transferred to the cover vaporization. In the cover gas system of the reactor, natural convection occurs due to temperature differences between the sodium pool and the gas phase. The release rates of VFPs together with sodium vaporization are considered to be controlled by the convection. In this study, three analytical models are developed and examined to calculate the transient release rates using the equilibrium partition coefficients of VFPs. The calculated release rates are compared with experimental results for sodium and sodium iodide. The release rate of sodium is closest to the calculation by the heterogeneous nucleation theory. The release rate of sodium iodide obtained from the experiment is between the release rates calculated by the model based on heat-and-mass transfer analogy and the Hills theory. From this study, it is confirmed that the realistic release rate of sodium is able to be calculated by the model based on the heterogeneous nucleation theory. The conservative release rate of sodium iodide is able to be calculated by the model based on the Hills theory using the equilibrium partition coefficient of sodium iodide. (author) 7 figs., 1 tab., 3 refs.

3. Hybridization and Selective Release of DNA Microarrays

Beer, N R; Baker, B; Piggott, T; Maberry, S; Hara, C M; DeOtte, J; Benett, W; Mukerjee, E; Dzenitis, J; Wheeler, E K

2011-11-29

DNA microarrays contain sequence specific probes arrayed in distinct spots numbering from 10,000 to over 1,000,000, depending on the platform. This tremendous degree of multiplexing gives microarrays great potential for environmental background sampling, broad-spectrum clinical monitoring, and continuous biological threat detection. In practice, their use in these applications is not common due to limited information content, long processing times, and high cost. The work focused on characterizing the phenomena of microarray hybridization and selective release that will allow these limitations to be addressed. This will revolutionize the ways that microarrays can be used for LLNL's Global Security missions. The goals of this project were two-fold: automated faster hybridizations and selective release of hybridized features. The first study area involves hybridization kinetics and mass-transfer effects. the standard hybridization protocol uses an overnight incubation to achieve the best possible signal for any sample type, as well as for convenience in manual processing. There is potential to significantly shorten this time based on better understanding and control of the rate-limiting processes and knowledge of the progress of the hybridization. In the hybridization work, a custom microarray flow cell was used to manipulate the chemical and thermal environment of the array and autonomously image the changes over time during hybridization. The second study area is selective release. Microarrays easily generate hybridization patterns and signatures, but there is still an unmet need for methodologies enabling rapid and selective analysis of these patterns and signatures. Detailed analysis of individual spots by subsequent sequencing could potentially yield significant information for rapidly mutating and emerging (or deliberately engineered) pathogens. In the selective release work, optical energy deposition with coherent light quickly provides the thermal energy

4. Biodegradable hollow fibres for the controlled release of drugs

Schakenraad, J.M.; Oosterbaan, J.A.; Nieuwenhuis, P.; Molenaar, I.; Olijslager, J.; Potman, W.; Eenink, M.J.D.; Feijen, Jan

1988-01-01

Biodegradable hollow fibres of poly-l-lactic acid (PLLA) filled with a suspension of the contraceptive hormone levonorgestrel in castor oil were implanted subcutaneously in rats to study the rate of drug release, rate of biodegradation and tissue reaction caused by the implant. The in vivo drug

5. Biodegradable hollow fibres for the controlled release of drugs

Schakenraad, J.M.; Oosterbaan, J.A.; Nieuwenhuis, P.; Molenaar, I.; Olijslager, J.; Potman, W.; Eenink, M.J.D.; Feijen, J.

1988-01-01

Biodegradable hollow fibres of poly-l-lactic acid (PLLA) filled with a suspension of the contraceptive hormone levonorgestrel in castor oil were implanted subcutaneously in rats to study the rate of drug release, rate of biodegradation and tissue reaction caused by the implant. The in vivo drug rele

6. Electrospinning nanofibers for controlled drug release

Banik, Indrani

Electrospinning is the most widely studied technique for the synthesis of nanofibers. Electrospinning is considered as one of the technologies that can produce nanosized drugs incorporated in polymeric nanofibers. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This technology has the potential for enhancing the oral delivery of poorly soluble drugs. The electrospun mats were made using Polycaprolactone/PCL, Poly(DL-lactide)/PDL 05 and Poly(DL-lactide-co-glycolide)/PLGA. The drugs incorporated in the electrospun fibers were 5-Fluorouracil and Rapamycin. The evidence of the drugs being embedded in the polymers was obtained by scanning electron microscopy (SEM), Raman and infrared spectroscopy. The release of 5-Fluorouracil and Rapamycin were followed by UV-VIS spectroscopy.

7. Release of Steroids from Plastibase Semisolid Bases

1991-07-01

Full Text Available The present research is carried out in order to study the possibility of replacing the classic semisolid bases in steroidal commercial products with Plastibase."nAs regard to its high lipophilic properties, the plastibase alone is not a suitable base for hydrocortisone acetate and f.luocinolone acetonide. Addition of 5 and 7.5% of Propylene glycol to plastibase can increase the rate of drug release from vehicle. This change in drug release is related to decrease in drug-vehicle interaction and consequently increasing its partition coefficient. It seems that these considerations can be applied to betamethasone and clobetasole ointments, which are the most utilized in Iranian commerce .

8. Iliopsoas Tendon Reformation after Psoas Tendon Release

K. Garala

2013-01-01

Full Text Available Internal snapping hip syndrome, or psoas tendonitis, is a recognised cause of nonarthritic hip pain. The majority of patients are treated conservatively; however, occasionally patients require surgical intervention. The two surgical options for iliopsoas tendinopathy are step lengthening of the iliopsoas tendon or releasing the tendon at the lesser trochanter. Although unusual, refractory snapping usually occurs soon after tenotomy. We report a case of a 47-year-old active female with internal snapping and pain following an open psoas tenotomy. Postoperatively she was symptom free for 13 years. An MRI arthrogram revealed reformation of a pseudo iliopsoas tendon reinserting into the lesser trochanter. The pain and snapping resolved after repeat iliopsoas tendon release. Reformation of tendons is an uncommon sequela of tenotomies. However the lack of long-term studies makes it difficult to calculate prevalence rates. Tendon reformation should be included in the differential diagnosis of failed tenotomy procedures after a period of symptom relief.

9. Iliopsoas tendon reformation after psoas tendon release.

Garala, K; Power, R A

2013-01-01

Internal snapping hip syndrome, or psoas tendonitis, is a recognised cause of nonarthritic hip pain. The majority of patients are treated conservatively; however, occasionally patients require surgical intervention. The two surgical options for iliopsoas tendinopathy are step lengthening of the iliopsoas tendon or releasing the tendon at the lesser trochanter. Although unusual, refractory snapping usually occurs soon after tenotomy. We report a case of a 47-year-old active female with internal snapping and pain following an open psoas tenotomy. Postoperatively she was symptom free for 13 years. An MRI arthrogram revealed reformation of a pseudo iliopsoas tendon reinserting into the lesser trochanter. The pain and snapping resolved after repeat iliopsoas tendon release. Reformation of tendons is an uncommon sequela of tenotomies. However the lack of long-term studies makes it difficult to calculate prevalence rates. Tendon reformation should be included in the differential diagnosis of failed tenotomy procedures after a period of symptom relief.

10. Externally controlled triggered-release of drug from PLGA micro and nanoparticles.

Xin Hua

Full Text Available Biofilm infections are extremely hard to eradicate and controlled, triggered and controlled drug release properties may prolong drug release time. In this study, the ability to externally control drug release from micro and nanoparticles was investigated. We prepared micro/nanoparticles containing ciprofloxacin (CIP and magnetic nanoparticles encapsulated in poly (lactic-co-glycolic acid PLGA. Both micro/nanoparticles were observed to have narrow size distributions. We investigated and compared their passive and externally triggered drug release properties based on their different encapsulation structures for the nano and micro systems. In passive release studies, CIP demonstrated a fast rate of release in first 2 days which then slowed and sustained release for approximately 4 weeks. Significantly, magnetic nanoparticles containing systems all showed ability to have triggered drug release when exposed to an external oscillating magnetic field (OMF. An experiment where the OMF was turned on and off also confirmed the ability to control the drug release in a pulsatile manner. The magnetically triggered release resulted in a 2-fold drug release increase compared with normal passive release. To confirm drug integrity following release, the antibacterial activity of released drug was evaluated in Pseudomonas aeruginosa biofilms in vitro. CIP maintained its antimicrobial activity after encapsulation and triggered release.

11. Controlled release of chlorhexidine from UDMA-TEGDMA resin.

Anusavice, K J; Zhang, N-Z; Shen, C

2006-10-01

Chlorhexidine salts are available in various formulations for dental applications. This study tested the hypothesis that the release of chlorhexidine from a urethane dimethacrylate and triethylene glycol dimethacrylate resin system can be effectively controlled by the chlorhexidine diacetate content and pH. The filler concentrations were 9.1, 23.1, or 33.3 wt%, and the filled resins were exposed to pH 4 and pH 6 acetate buffers. The results showed that Fickian diffusion was the dominant release mechanism. The rates of release were significantly higher in pH 4 buffer, which was attributed to the increase of chlorhexidine diacetate solubility at lower pH. The higher level of filler loading reduced the degree of polymerization, leading to a greater loss of organic components and higher chlorhexidine release rates.

12. Evaluation of Drug Release From Coated Pellets Based on Isomalt, Sugar, and Microcrystalline Cellulose Inert Cores

2010-01-01

The objective of the present study was to investigate the effect of the pellet core materials isomalt, sugar, and microcrystalline cellulose on the in vitro drug release kinetics of coated sustained-release pellets as well as to evaluate the influence of different ratios of polymethacrylate copolymers exhibiting different permeability characteristics on the drug release rate. For characterization of the drug release process of pellets, the effect of osmolality was studied using glucose as an ...

13. Controlled Release of the Indomethacin Microencapsulation Based on Layer-by-layer Assembly by Polyelectrolyte Multilayers

CHEN You-fang; LIN Xian-fu

2007-01-01

Indomethacin has been encapsulated with polyelectrolyte multilayers for controlled release. Gelatin and alginate were alternatively deposited on indomethacin microcrystals. The released amount of indomethacin from coated microcrystals in pH6. 8phosphate buffer solution (PBS) was measured with a UV spectrophometer. The polyelectrolyte multilayer capsule thickness was proved to control the release rate. The effects of osmotic pressure existed during the release process of indomethacin from microcapsules coated by (gelatin/alginate) 4.

14. Influence of lambda-carrageenan on the release of systematic series of volatile flavor compounds from viscous food model systems

Bylaite, Egle; Ilgunaite, Z.; Meyer, Anne Boye Strunge

2004-01-01

, except with the most hydrophobic compounds. Analysis of flavor release under nonequilibrium conditions revealed a suppressing effect of lambda-carrageenan on the release rates of aroma compounds, and the extent of decrease in release rates was dependent on the physicochemical characteristics of the aroma...

15. Arthroscopic tennis elbow release.

Savoie, Felix H; O'Brien, Michael J

2015-01-01

Lateral epicondylitis, originally referred to as tennis elbow, affects between 1% and 3% of the population and is usually found in patients aged 35 to 50 years. Although it was initially thought that lateral epicondylitis was caused by an inflammatory process, most microscopic studies of excised tissue demonstrate a failure of reparative response in the extensor carpi radialis brevis tendon and in any of the associated structures. Most cases of lateral epicondylitis respond to appropriate nonsurgical treatment protocols, which include medication, bracing, physical therapy, corticosteroid injections, shock wave therapy, platelet-rich plasma, and low-dose thermal or ultrasound ablation devices. However, when these protocols are unsuccessful, surgical measures may be appropriate and have a high rate of success. The results of arthroscopic surgical procedures have documented satisfactory results, with improvement rates reported between 91% and 97.7%. Recent advances in arthroscopic repair and plication of these lesions, along with recognizing the presence and repair of coexisting lesions, have allowed arthroscopic techniques to provide excellent results.

16. Controlled release of tocopherols from polymer blend films

Obinata, Noe

Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies

17. Preparation and characterization of metoprolol controlled-release solid dispersions.

Varshosaz, Jaleh; Faghihian, Hossein; Rastgoo, Kobra

2006-01-01

In recent years, great attention has been paid to using solid dispersions to make sustained-release drugs. The objective of this study is to produce sustained-release systems of metoprolol tartrate using solid dispersion techniques and to evaluate their physicochemical characteristics. The solid dispersions were produced by melting and solvent methods, containing 7%, 15%, or 25% of the drug and different ratios of Eudragit RLPO and RSPO in ratios of 0:10, 3:7, 5:5, 7:3, and 10:0. Drug release profiles were determined by USP XXIII rotating paddle method in phosphate buffer solution (pH 6.8). XRD, DSC, IR, and microscopic observations were performed to evaluate the physical characteristics of solid dispersions. Results showed that the drug release from dispersions was at a slower rate than pure drug and physical mixtures. Moreover, the formulations containing greater ratios of Eudragit RSPO showed slower release rates and smaller DE8% but larger mean dissolution time than those containing greater ratios of Eudragit RLPO. Dispersions with particle size of less than 100 microm containing 7% of metoprolol and Eudragit RL:RS 5:5 (solvent method) and those with the ratio of 3:7 (melting method) had similar release pattern to Lopressor sustained-release tablets by zero-order and Higuchi kinetics, respectively.

18. Analysis of LNG import terminal release prevention systems

Baker, E G

1982-04-01

The release prevention systems of liquefied natural gas (LNG) import terminal were analyzed. A series of potential release scenarios were analyzed to determine the frequency of the release events, the probability these releases are not stopped or isolated by emergency shutdown systems, the estimated release quantities, and the critical components of the system. The two plant areas identified as being most significant with respect to safety are the unloading system and the storage system. Rupture of the main transfer line and gross failure of the storage tanks are the two release scenarios of primary safety interest. Reducing the rate of failure by improved design, better maintenance and testing, or adding redundancy of the critical system components for these plant areas and release scenarios will result in improved safety. Several design alternatives which have the potential to significantly reduce the probability of a large release of LNG occurring at an import terminal are identified. These design alternatives would reduce the probability of a large release of LNG by reducing the expected number of failures which could cause a release or by reducing the magnitude of releases that do occur. All of these alternatives are technically feasible and have been used or considered for use in at least one LNG facility. A more rigorous analysis of the absolute risk of LNG import terminal operation is necessary before the benefits of these design alternatives can be determined. In addition, an economic evaluation of these alternatives must be made so the costs and benefits can be compared. It is concludd that for remotely located facilities many of these alternatives are probably not justified; however, for facilities located in highly populated areas, these alternatives deserve serious consideration.

19. Mesoporous hydroxyapatite: Preparation, drug adsorption, and release properties

Gu, Lina; He, Xiaomei; Wu, Zhenyu, E-mail: zhenyuwuhn@sina.com

2014-11-14

Mesoporous hydroxyapatite (HA) was synthesized through gas–liquid chemical precipitation method at ambient temperature without any template. Structure, morphology and pore size distribution of HA were analyzed via X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution electron microscopy and N{sub 2} adsorption/desorption. The chemotherapeutic agent doxorubicin (DOX) was used to investigate the drug adsorption and release behavior of HA. The kinetics of DOX adsorption on HA followed the pseudo-second-order rate expression. Adsorption isotherms at various temperatures were obtained, and the equilibrium data fitted the Langmuir model. The values of thermodynamic parameters (Gibbs free energy, entropy, and enthalpy changes) demonstrated that the adsorption process was spontaneous and endothermic. In vitro pH-responsive (pH = 7.4, 5.8) controlled release was investigated. DOX-loaded HA showed a slow, long-term, and steady release rate. The release rate at pH5.8 was larger than that at pH7.4. Consequently, the as-prepared mesoporous HA has potential applications in controlled drug delivery systems. - Highlights: • Mesoporous HA was synthesized by a simple precipitation method without any template. • The kinetics of adsorption followed the pseudo-second-order rate expression. • Thermodynamics investigation showed that adsorption was spontaneous and endothermic. • DOX-loaded HA showed a long-term, steady, and pH-controlled release rate.

20. Modeling of Fission Gas Release in UO2

MH Krohn

2006-01-23

A two-stage gas release model was examined to determine if it could provide a physically realistic and accurate model for fission gas release under Prometheus conditions. The single-stage Booth model [1], which is often used to calculate fission gas release, is considered to be oversimplified and not representative of the mechanisms that occur during fission gas release. Two-stage gas release models require saturation at the grain boundaries before gas is release, leading to a time delay in release of gases generated in the fuel. Two versions of a two-stage model developed by Forsberg and Massih [2] were implemented using Mathcad [3]. The original Forsbers and Massih model [2] and a modified version of the Forsberg and Massih model that is used in a commercially available fuel performance code (FRAPCON-3) [4] were examined. After an examination of these models, it is apparent that without further development and validation neither of these models should be used to calculate fission gas release under Prometheus-type conditions. There is too much uncertainty in the input parameters used in the models. In addition. the data used to tune the modified Forsberg and Massih model (FRAPCON-3) was collected under commercial reactor conditions, which will have higher fission rates relative to Prometheus conditions [4].

1. Modulation of venlafaxine hydrochloride release from press coated matrix tablet

Gohel M

2008-01-01

Full Text Available The aim of present study was to prepare novel modified release press coated tablets of venlafaxine hydrochloride. Hydroxypropylmethylcellulose K4M and hydroxypropylmethylcellulose K100M were used as release modifier in core and coat, respectively. A 3 2 full factorial design was adopted in the optimization study. The drug to polymer ratio in core and coat were chosen as independent variables. The drug release in the first hour and drug release rate between 1 and 12 h were chosen as dependent variables. The tablets were characterized for dimension analysis, crushing strength, friability and in vitro drug release. A check point batch, containing 1:2.6 and 1:5.4 drug to polymer in core and coat respectively, was prepared. The tablets of check point batch were subjected to in vitro drug release in dissolution media with pH 5, 7.2 and distilled water. The kinetics of drug release was best explained by Korsmeyer and Peppas model (anomalous non-Fickian diffusion. The systematic formulation approach enabled us to develop modified release venlafaxine hydrochloride tablets.

2. Modulation of venlafaxine hydrochloride release from press coated matrix tablet.

Gohel, M C; Soni, C D; Nagori, S A; Sarvaiya, K G

2008-01-01

The aim of present study was to prepare novel modified release press coated tablets of venlafaxine hydrochloride. Hydroxypropylmethylcellulose K4M and hydroxypropylmethylcellulose K100M were used as release modifier in core and coat, respectively. A 3(2) full factorial design was adopted in the optimization study. The drug to polymer ratio in core and coat were chosen as independent variables. The drug release in the first hour and drug release rate between 1 and 12 h were chosen as dependent variables. The tablets were characterized for dimension analysis, crushing strength, friability and in vitro drug release. A check point batch, containing 1:2.6 and 1:5.4 drug to polymer in core and coat respectively, was prepared. The tablets of check point batch were subjected to in vitro drug release in dissolution media with pH 5, 7.2 and distilled water. The kinetics of drug release was best explained by Korsmeyer and Peppas model (anomalous non-Fickian diffusion). The systematic formulation approach enabled us to develop modified release venlafaxine hydrochloride tablets.

3. Reaction-Multi Diffusion Model for Nutrient Release and Autocatalytic Degradation of PLA-Coated Controlled-Release Fertilizer

Sayed Ameenuddin Irfan

2017-03-01

Full Text Available A mathematical model for the reaction-diffusion equation is developed to describe the nutrient release profiles and degradation of poly(lactic acid (PLA-coated controlled-release fertilizer. A multi-diffusion model that consists of coupled partial differential equations is used to study the diffusion and chemical reaction (autocatalytic degradation simultaneously. The model is solved using an analytical-numerical method. Firstly, the model equation is transformed using the Laplace transformation as the Laplace transform cannot be inverted analytically. Numerical inversion of the Laplace transform is used by employing the Zakian method. The solution is useful in predicting the nutrient release profiles at various diffusivity, concentration of extraction medium, and reaction rates. It also helps in explaining the transformation of autocatalytic concentration in the coating material for various reaction rates, times of reaction, and reaction-multi diffusion. The solution is also applicable to the other biodegradable polymer-coated controlled-release fertilizers.

4. Commercial SNF Accident Release Fractions

J. Schulz

2004-11-05

The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the

5. Protein release from electrospun nonwovens: improving the release characteristics through rational combination of polyester blend matrices with polidocanol.

Puhl, Sebastian; Ilko, David; Li, Linhao; Holzgrabe, Ulrike; Meinel, Lorenz; Germershaus, Oliver

2014-12-30

Nonwoven scaffolds consisting of poly-ε-caprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) and polidocanol (PD), and loaded with lysozyme crystals were prepared by electrospinning. The composition of the matrix was varied and the effect of PD content in binary mixtures, and of PD and PLGA content in ternary mixtures regarding processability, fiber morphology, water sorption, swelling and drug release was investigated. Binary PCL/PD blend nonwovens showed a PD-dependent increase in swelling of up to 30% and of lysozyme burst release of up to 45% associated with changes of the fiber morphology. Furthermore, addition of free PD to the release medium resulted in a significant increase of lysozyme burst release from pure PCL nonwovens from approximately 2-35%. Using ternary PCL/PD/PLGA blends, matrix degradation could be significantly improved over PCL/PD blends, resulting in a biphasic release of lysozyme with constant release over 9 weeks, followed by constant release with a reduced rate over additional 4 weeks. Based on these results, protein release from PCL scaffolds is improved by blending with PD due to improved lysozyme desorption from the polymer surface and PD-dependent matrix swelling. Copyright © 2014 Elsevier B.V. All rights reserved.

6. Temporal control of drug release from biodegradable polymer: multicomponent diclofenac sodium releasing PLGA 80/20 rod.

Nikkola, Lila; Viitanen, Petrus; Ashammakhi, Nureddin

2009-05-01

In our previous studies we have reported on the development of diclofenac sodium (DS) releasing rods. However, their drug release profiles were unsatisfactory. To enhance the drug release properties of the implant, we have developed a system whereby various elements can be combined into one implant. Melt extruded, self-reinforced (SR), and sterilized (S) DS-containing SR-PLGA 80/20 billets were combined to produce multicomponent implants with various compositions. These components were basically heat pressed together to form multicomponent rods. Drug release from single component and multicomponent rods was defined using a UV-Vis spectrophotometer. DS was released from individual components within 82-111 days and from multicomponent rods within 50-70 days. Thermal properties were analyzed using differential scanning calorimetry (DSC). The melting temperature (T(m)) of multicomponent implants was about 157 degrees C, change in heat fusion (DeltaH) was 13.3 J/g, and the glass transition temperature (T(g)) was 55.4 degrees C. Mechanical strength was measured for 2 weeks and it decreased from 55 to 15 MPa. In conclusion, by compression molding three components with different release rates it is possible to control the temporal release from multicomponent rods. Released DS concentrations were within range for 49-74 days depending on the fractions of individual components used.

7. Ratings Revisited

Lai, Signe Sophus

2015-01-01

tværs af medier og platforme, forskudt i tid og on-demand. This article focuses on audience ratings, which have functioned as the central ‘currency’ informing the media trade. It discusses changes to the production and accuracy of audience ratings at a time when established standards are being...... consumption. It argues that current tracking systems cannot capture increasingly cross-media, time-shifted, mobile, and on-demand audience behavior....

8. Birth control - slow release methods

... page: //medlineplus.gov/ency/article/007555.htm Birth control - slow release methods To use the sharing features on this page, please enable JavaScript. Certain birth control methods contain man-made forms of hormones. These ...

9. Turbulent lock release gravity current

2001-01-01

The time evolution of a turbulent lock release gravity current, formed by a finite volume ofhomogeneous fluid released instantaneously into another fluid of slightly lower density, was studied byexperimental measurements of the density structure via elaborate digital image processing and by a nu-merical simulation of the flow and mixing using a two-equation turbulence model. The essential fact thatthe gravity current passes through an initial slumping phase in which the current head advances steadilyand a second self-similar phase in which the front velocity decreases like the negative third power of thetime after release is satisfactorily presented by the laboratory observation. An overall entrainment ratioproportional to the distance from the release point is found by the numerical simulation. The renormal-ization group (RNG) k- ε model for Reynolds-stress closure is validated to characterize the gravitycurrent with transitional and localized turbulence.

10. PCDD/PCDF release inventories

Fiedler, H. [UNEP Chemicals, Chatelaine (Switzerland)

2004-09-15

The Stockholm Convention on Persistent Organic Pollutants (POPs) entered into force on 17 May 2004 with 50 Parties. In May 2004, 59 countries had ratified or acceded the Convention. The objective of the Convention is ''to protect human health and the environment from persistent organic pollutants''. For intentionally produced POPs, e.g., pesticides and industrial chemicals such as hexachlorobenzene and polychlorinated biphenyls, this will be achieved by stop of production and use. For unintentionally generated POPs, such as polychlorinated dibenzo-pdioxins (PCDD) and polychlorinated dibenzofurans (PCDF), measures have to be taken to ''reduce the total releases derived from anthropogenic sources''; the final goal is ultimate elimination, where feasible. Under the Convention, Parties have to establish and maintain release inventories to prove the continuous release reduction. Since many countries do not have the technical and financial capacity to measure all releases from all potential PCDD/PCDF sources, UNEP Chemicals has developed the ''Standardized Toolkit for the Identification of Quantification of Dioxin and Furan Releases'' (''Toolkit'' for short), a methodology to estimate annual releases from a number of sources. With this methodology, annual releases can be estimated by multiplying process-specific default emission factors provided in the Toolkit with national activity data. At the seventh session of the Intergovernmental Negotiating Committee, the Toolkit was recommended to be used by countries when reporting national release data to the Conference of the Parties. The Toolkit is especially used by developing countries and countries with economies in transition where no measured data are available. Results from Uruguay, Thailand, Jordan, Philippines, and Brunei Darussalam have been published.

11. Uniformity of Peptide Release Is Maintained by Methylation of Release Factors

William E. Pierson

2016-09-01

Full Text Available Termination of protein synthesis on the ribosome is catalyzed by release factors (RFs, which share a conserved glycine-glycine-glutamine (GGQ motif. The glutamine residue is methylated in vivo, but a mechanistic understanding of its contribution to hydrolysis is lacking. Here, we show that the modification, apart from increasing the overall rate of termination on all dipeptides, substantially increases the rate of peptide release on a subset of amino acids. In the presence of unmethylated RFs, we measure rates of hydrolysis that are exceptionally slow on proline and glycine residues and approximately two orders of magnitude faster in the presence of the methylated factors. Structures of 70S ribosomes bound to methylated RF1 and RF2 reveal that the glutamine side-chain methylation packs against 23S rRNA nucleotide 2451, stabilizing the GGQ motif and placing the side-chain amide of the glutamine toward tRNA. These data provide a framework for understanding how release factor modifications impact termination.

12. Effect of diluents on tablet integrity and controlled drug release.

Zhang, Y E; Schwartz, J B

2000-07-01

The objective of this study was to evaluate the effect of diluents and wax level on tablet integrity during heat treatment and dissolution for sustained-release formulations and the resultant effect on drug release. Dibasic calcium phosphate dihydrate (DCPD), microcrystalline cellulose (MCC), and lactose were evaluated for their effect on tablet integrity during drug dissolution and heat treatment in wax matrix formulations. A newly developed direct compression diluent, dibasic calcium phosphate anhydrous (DCPA), was also evaluated. Compritol 888 ATO was used as the wax matrix material, with phenylpropanolamine hydrochloride (PPA) as a model drug. Tablets were made by direct compression and then subjected to heat treatment at 80 degrees C for 30 min. The results showed that MCC, lactose, and DCPA could maintain tablets intact during heat treatment above the melting point of wax (70 degrees C-75 degrees C). However, DCPD tablets showed wax egress during the treatment. MCC tablets swelled and cracked during drug dissolution and resulted in quick release. DCPD and lactose tablets remained intact during dissolution and gave slower release than MCC tablets. DCPA tablets without heat treatment disintegrated very quickly and showed immediate release. In contrast, heat-treated DCPA tablets remained intact through the 24-hr dissolution test and only released about 80% PPA at 6 hr. In the investigation of wax level, DCPD was used as the diluent. The drug release rate decreased as the wax content increased from 15% to 81.25%. The dissolution data were best described by the Higuchi square-root-of-time model. Diluents showed various effects during heat treatment and drug dissolution. The integrity of the tablets was related to the drug release rate. Heat treatment retarded drug release if there was no wax egress.

13. Influence of pore water velocity on the release of carbofuran and fenamiphos from commercial granulates embedded in a porous matrix

Paradelo, Marcos; Pérez-Rodríguez, Paula; Arias-Estévez, Manuel; López-Periago, J. Eugenio

2012-11-01

Pore water flow velocity can influence the processes involved in the contaminant transport between relative stagnant zones of porous media and their adjacent mobile zones. A particular case of special interest is the occurrence of high flow rates around the controlled release granules containing pesticides buried in soil. The release of the pesticides carbofuran and fenamiphos from commercial controlled release formulations (CRFs) was studied, comparing release tests in a finite volume of water with water flow release tests in saturated packed sand at different seepage velocities. For water release kinetics, the time taken for 50% of the pesticide to be released (T50) was 0.64 hours for carbofuran and 1.97 hours for fenamiphos. In general, the release rate was lower in the porous matrix than in the free water tests. The faster release rate for carbofuran was attributed to its higher water diffusivity. The seepage velocity has a strong influence on the pesticide release rate. The dominant release mechanism varies with the progress of release. The evolution of the mechanism is discussed on the basis of the successive steps that involve the moving boundary of the dissolution front of the pesticide inside the granule, the concentration gradient inside the granule and the flow boundary layer resistance to solute diffusion around the granule. The pore water velocity influences the overall release dynamics. Therefore, seepage velocity should be considered in pesticide release to evaluate the risk of pesticide leaching, especially in scenarios with fast infiltration.

14. Formulation and Evaluation Of Sustained Release Matrix Tablets of Lornoxicam

Syed Namath Ulla

2011-03-01

Full Text Available Lornoxicam, a potent non-steroidal anti-inflammatory drug which has short half life, makes the development of sustained release (SR forms extremely advantageous. However, due to its weak acidic nature, its release from SR delivery systems is limited to the lower gastrointestinal tract which consequently leads to a delayed onset of its analgesic action. Therefore, the present investigation of this study was to develop Lornoxicam SR matrix tablets that provide complete drug release that starts in the stomach to rapidly alleviate the painful symptoms and continues in the intestine to maintain analgesic effect. Lornoxicam showed maximum absorption at wavelength 373 nm in 0.1N HCl and 379 nm in pH 6.8. Drug-polymer compatibility studies by FTIR gave confirmation about their purity and showed no interaction between drug and selected polymers. Various formulations were developed by using release rate controlling and gel forming polymers like HPMC (K4M, K15M, K100M by direct compression method. From among all the developed formulations, F1 formulation sustained the drug release for longer period of time as compared to other formulations. So, F1 was selected as the best formulation. It was concluded that the release followed zero order kinetics, as the correlation coefficient (R2 value was higher for zero order release, so the drug release mechanism is controlled release. The best formulation was found to be stable during stability studies for two months. Thus, best formulation satisfied physicochemical parameters and in vitro drug release profile requirements for a sustained drug delivery system.

15. Fabrication and Evaluation of Multilayer Nanofiber-Hydrogel Meshes with a Controlled Release Property

Rigumula Wu

2015-07-01

Full Text Available Controlled release drug delivery systems enable the sustained release of bioactive molecules, and increase bioavailability over an extended length of time. Biocompatible and biodegradable materials such as polycaprolactone (PCL nanofibers and alginate hydrogel play a significant role in designing controlled release systems. Prolonged release of bioactive molecules is observed when these polymer materials are used as matrices independently. However, there has not been a report in the literature that shows how different molecules are released at various rates over time. The goal of this study is to demonstrate a novel drug delivery system that has a property of releasing designated drugs at various rates over a defined length of time. We fabricated multilayer nanofiber-hydrogel meshes using electrospun PCL nanofiber and alginate hydrogel, and evaluated their controlled release properties. The multilayer meshes are composed of sandwiched layers of alternating PCL nanofibers and alginate hydrogel. Adenosine triphosphate (ATP, encapsulated in the designated hydrogel layers, is used as a mock drug for the release study. The exposed top layer of the meshes demonstrates a dramatically higher burst release and shorter release time compared to the deeper layers. Such properties of the different layers within the meshes can be employed to achieve the release of multiple drugs at different rates over a specified length of time.

16. Early release of neonatal ureteral obstruction preserves renal function

Shi, Yimin; Pedersen, Michael; Li, Chunling;

2004-01-01

.05) after 24 wk. Similarly, glomerular filtration rate of the obstructed kidney was severely reduced at 24 wk: 172 ± 36 vs. 306 ± 42 μl·min−1·100 g body wt−1 (P reduction in total protein content...... downregulation of Na-K-ATPase to 62 ± 7%, aquaporin-1 to 53 ± 3%, and aquaporin-3 to 53 ± 7% of sham levels. Release after 1 wk completely prevented development of hydronephrosis, reduction in RBF and glomerular filtration rate, and downregulation of renal transport proteins, whereas release after 4 wk had...

17. Spatiotemporal Programing for the On-Demand Release of Bupivacaine Based on an Injectable Composite Hydrogel.

Dinh, Van Vuong; Suh, Yun-Suhk; Yang, Han-Kwang; Lim, Yong Taik

2016-12-01

We report a programed drug delivery system that can tailor the release of anesthetic bupivacaine in a spatiotemporally controlled manner. The drug delivery system was developed through the combination of a collagen-based injectable hydrogel and 2 types of poly(lactic-co-glycolic acid) (PLGA) particles. As a rapid-release platform (90% release after 24 h), bupivacaine hydrochloride was incorporated into collagen/poly(γ-glutamic acid) hydrogel, which exhibited gel formation at body temperature. PLGA microparticles (diameter 1-3 μm) containing bupivacaine base showed a very slow release of bupivacaine (95% after 240 h), whereas PLGA nanoparticles (124 ± 30 nm) containing bupivacaine base demonstrated an intermediate release rate (95% after 160 h). By changing the relative composition ratio between the 3 components in these injectable composite hydrogels, the release of bupivacaine could be easily controlled from very rapid (within 1 day) to very delayed (up to 9 days). The experimental results on the release data (cumulative release, time point release, average release rate) were coincident with the release profile generated by computer simulation. These injectable composite hydrogels with systematically tunable mixing ratios are expected to serve as a promising technology for the on-demand release of bupivacaine in pain management. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

18. Controlled-release of Avermectin from Organically Modified Hydrotalcite-like Compound Nanohybrids

QIU,Depeng; LI,Yonghai; FU,Xiying; JIANG,Zhen; ZHAO,Xinyan; WANG,Tian; HOU,Wanguo

2009-01-01

The intercalation of avermectin (AVM)into sodium dodecyl sulfate(SDS)modified hydrotalcite-like com-pounds(HTlc) was carried out using an evaporating solvent enhanced intercalation method to obtain AVM-SDS-HTlc nanohybrids. It was found that the nanohybrids could well control the release of avermectin, showing the nanohybrids are a potential pesticide controlled-release formulation.The release of avermectin from AVM-SDS-HTlc nanohybrids is dependent on the pH.temperature and the presence of electrolyte in release me-dium. Acidic medium and higher temperature and the presence of electrolytes may induce the higher release rate of avermectin. The release process of avermectin from AVM-SDS-HTlc nanohybrids can be described by pseudo-first-order release kinetics, and the activation energy of release is 279 kJ/mol.

19. Radiological effluents released from US continental tests, 1961 through 1992. Revision 1

Schoengold, C.R.; DeMarre, M.E.; Kirkwood, E.M.

1996-08-01

This report documents all continental tests from September 15, 1961, through September 23, 1992, from which radioactive effluents were released. The report includes both updated information previously published in the publicly available May, 1990 report, DOE/NV-317, Radiological Effluents Released from Announced US Continental Tests 1961 through 1988`, and effluent release information on formerly unannounced tests. General information provided for each test includes the date, time, location, type of test, sponsoring laboratory and/or agency or other sponsor, depth of burial, purpose, yield or yield range, extent of release (onsite only or offsite), and category of release (detonation-time versus post-test operations). Where a test with simultaneous detonations is listed, location, depth of burial and yield information are given for each detonation if applicable, as well as the specific source of the release. A summary of each release incident by type of release is included. For a detonation-time release, the effluent curies are expressed at R+12 hours. For a controlled releases from tunnel-tests, the effluent curies are expressed at both time of release and at R+12 hours. All other types are listed at the time of the release. In addition, a qualitative statement of the isotopes in the effluent is included for detonation-time and controlled releases and a quantitative listing is included for all other types. Offsite release information includes the cloud direction, the maximum activity detected in the air offsite, the maximum gamma exposure rate detected offsite, the maximum iodine level detected offsite, and the maximum distance radiation was detected offsite. A release summary incudes whatever other pertinent information is available for each release incident. This document includes effluent release information for 433 tests, some of which have simultaneous detonations. However, only 52 of these are designated as having offsite releases.

20. Release behaviour of clozapine matrix pellets based on percolation theory.

Aguilar-de-Leyva, Angela; Sharkawi, Tahmer; Bataille, Bernard; Baylac, Gilles; Caraballo, Isidoro

2011-02-14

The release behaviour of clozapine matrix pellets was studied in order to investigate if it is possible to explain it applying the concepts of percolation theory, previously used in the understanding of the release process of inert and hydrophilic matrix tablets. Thirteen batches of pellets with different proportions of clozapine/microcrystalline cellulose (MCC)/hydroxypropylmethyl cellulose (HPMC) and different clozapine particle size fractions were prepared by extrusion-spheronisation and the release profiles were studied. It has been observed that the distance to the excipient (HPMC) percolation threshold is important to control the release rate. Furthermore, the drug percolation threshold has a big influence in these systems. Batches very close to the drug percolation threshold, show a clear effect of the drug particle size in the release rate. However, this effect is much less evident when there is a bigger distance to the drug percolation threshold, so the release behaviour of clozapine matrix pellets is possible to be explained based on the percolation theory.

1. Controlled-release NPK fertilizer encapsulated by polymeric membranes.

Jarosiewicz, Anna; Tomaszewska, Maria

2003-01-15

The commercial granular fertilizer NPK6-20-30 was coated using polysulfone (PSF), polyacrylonitrile (PAN), and cellulose acetate (CA). The coatings were formed from the polymer solutions by the phase inversion technique. Measurements of the thickness and porosity of the prepared coatings and a microphotographic observation of the coatings were performed. The physical properties of the coatings influence the release rate of macronutrients which are present in the core of the coated fertilizer. In the case of PAN coating with 60.45% porosity, prepared from a 16% polymer solution, 100% of NH(4)(+) and P(2)O(5) was released after 4 h of test and 99.7% of K(+) after 5 h of test, whereas in the case of coating with 48.8% porosity, 31.8% of NH(4)(+), 16.7% of P(2)O(5), and 11.6% of K(+) was released after 5 h. In all experiments, different selectivities of the coatings in terms of the release of components were observed. The release of potassium through the coatings made of PSF and PAN was the slowest. The same tendency was observed for the release of nitrogen through a coating of CA. The release of fertilizer active components was the slowest in the case of PSF. The lowest porosity coating was prepared from the 18% PSF solution.

2. Toxic chemical considerations for tank farm releases. Revision 1

Van Keuren, J.C.

1995-11-01

This document provides a method of determining the toxicological consequences of accidental releases from Hanford Tank Farms. A determination was made of the most restrictive toxic chemicals that are expected to be present in the tanks. Concentrations were estimated based on the maximum sample data for each analyte in all the tanks in the composite. Composite evaluated were liquids and solids from single shell tanks, double shell tanks, flammable gas watch list tanks, as well as all solids, all liquids, head space gases, and 241-C-106 solids. A sum of fractions of the health effects was computed for each composite for unit releases based emergency response planning guidelines (ERPGs). Where ERPGs were not available for chemical compounds of interest, surrogate guidelines were established. The calculation method in this report can be applied to actual release scenarios by multiplying the sum of fractions by the release rate for continuous releases, or the release amount for puff releases. Risk guidelines are met if the product is less than for equal to one.

3. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

2013-01-01

Abstract Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography–mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

4. Aluminum corrosion product release kinetics

Edwards, Matt, E-mail: Matthew.Edwards@cnl.ca; Semmler, Jaleh; Guzonas, Dave; Chen, Hui Qun; Toor, Arshad; Hoendermis, Seanna

2015-07-15

Highlights: • Release of Al corrosion product was measured in simulated post-LOCA sump solutions. • Increased boron was found to enhance Al release kinetics at similar pH. • Models of Al release as functions of time, temperature, and pH were developed. - Abstract: The kinetics of aluminum corrosion product release was examined in solutions representative of post-LOCA sump water for both pressurized water and pressurized heavy-water reactors. Coupons of AA 6061 T6 were exposed to solutions in the pH 7–11 range at 40, 60, 90 and 130 °C. Solution samples were analyzed by inductively coupled plasma atomic emission spectroscopy, and coupon samples were analyzed by secondary ion mass spectrometry. The results show a distinct “boron effect” on the release kinetics, expected to be caused by an increase in the solubility of the aluminum corrosion products. New models were developed to describe both sets of data as functions of temperature, time, and pH (where applicable)

5. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

Kan, Xianwen; Geng, Zhirong; Zhao, Yao; Wang, Zhilin; Zhu, Jun-Jie

2009-04-01

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe3O4 nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

6. Formulation and Dissolution Study of Valsartan Immediate Release Tablets

B. Brahmaiah*, K. Sasikanth, Sreekanth Nama , P.Suresh, Patan Adam Khan

2013-06-01

Full Text Available In the present study, design of oral immediate release tablets of Valsartan by direct compression techniquewas carried out. The main aim and objective of the work is to formulate immediate release tablets usingdifferent direct compression vehicles (DCV’S in different ratios. The main motive is to compare thedissolution profile of these formulations and conclude the best formulation which release drug at a fasterrate. To determine the best fit dissolution profile for the dosage forms. Valsartan tablets were formulated byusing microcrystalline cellulose (diluents, potato starch, acacia (binder and magnesium stearate(lubricant. The granules were compressed into tablets and were subjected to dissolution studies. Thedissolution profile of the formulation F2 was found to have better dissolution rate compared to others. TheIn-vitro dissolution studies of all the formulations were conducted and the results were obtained, it wasconcluded that formulation F2 was the best with fast release of drug compared to others.

7. Hexamethylenetetramine carboxyborane: synthesis, structural characterization and CO releasing properties.

Ayudhya, T I; Raymond, C C; Dingra, N N

2017-01-17

Carbon monoxide, although widely known as a toxic gas, has received great attention in the past few decades due to its promising role as a medical gas. Several classes of carbon monoxide releasing molecules (CORMs) have been synthesised with many of them having pharmacological activities under physiological conditions. Herein, we report the synthesis and structural characterization of the first example of amine carboxyborane that releases CO under physiological conditions without the aid of inducers. A representative compound hexamethylenetetramine carboxyborane (HMTA-CB) described here has a half-life of 2.7 days and gradually releases CO with the rate constant of 3.0 × 10(-6) s(-1). Its ability to promote cell growth shows the beneficial effect of slow CO release to supplement CO in small amounts over time.

8. Magnetic molecularly imprinted polymer for aspirin recognition and controlled release

Kan Xianwen; Geng Zhirong; Zhao Yao; Wang Zhilin; Zhu Junjie [State Key Laboratory of Coordination Chemistry, MOE Key Lab of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)], E-mail: wangzl@nju.edu.cn, E-mail: jjzhu@nju.edu.cn

2009-04-22

Core-shell structural magnetic molecularly imprinted polymers (magnetic MIPs) with combined properties of molecular recognition and controlled release were prepared and characterized. Magnetic MIPs were synthesized by the co-polymerization of methacrylic acid (MAA) and trimethylolpropane trimethacrylate (TRIM) around aspirin (ASP) at the surface of double-bond-functionalized Fe{sub 3}O{sub 4} nanoparticles in chloroform. The obtained spherical magnetic MIPs with diameters of about 500 nm had obvious superparamagnetism and could be separated quickly by an external magnetic field. Binding experiments were carried out to evaluate the properties of magnetic MIPs and magnetic non-molecularly imprinted polymers (magnetic NIPs). The results demonstrated that the magnetic MIPs had high adsorption capacity and selectivity to ASP. Moreover, release profiles and release rate of ASP from the ASP-loaded magnetic MIPs indicated that the magnetic MIPs also had potential applications in drug controlled release.

9. Drug release kinetics from carboxymethylcellulose-bacterial cellulose composite films.

Juncu, Gheorghe; Stoica-Guzun, Anicuta; Stroescu, Marta; Isopencu, Gabriela; Jinga, Sorin Ion

2016-08-30

Composite films of sodium carboxymethyl cellulose and bacterial cellulose (NaCMC-BC) cross-linked with citric acid (CA) were prepared by solution casting method. Ibuprofen sodium salt (IbuNa) has been used to study the mechanism of drug release from composite films. Surface morphology was investigated by scanning electron microscopy (SEM) and proved that the BC content influences the aspect of the films. Fourier transformed infrared spectroscopy (FTIR) revealed specific peaks in IR spectra of composite films which sustain that NaCMC was cross-linked with CA. Starting from swelling observations, the release kinetic of IbuNa was described using a model which neglects the volume expansion due to polymer swelling and which considers non-linear diffusion coefficients for drug and solvent. The IbuNa release is also influenced by BC content, the drug release rate was decreasing with the increase of BC content.

10. Pramipexole extended release: in Parkinson's disease.

Chwieduk, Claudine M; Curran, Monique P

2010-04-01

Pramipexole extended release (ER) is a non-ergolinic dopamine receptor agonist available for use as a once-daily oral treatment for the signs and symptoms of early and advanced idiopathic Parkinson's disease. Once-daily pramipexole ER and three times-daily pramipexole immediate release (IR) have similar exposure over 24 hours. The ER formulation is associated with fewer fluctuations in plasma pramipexole concentrations over this period. Pramipexole ER improved the symptoms of Parkinson's disease in three well designed trials in adults with early or advanced disease, as measured by changes from baseline in the sum of the Unified Parkinson's Disease Rating Scale (UPDRS) parts II and III subtotal scores. In a 9-week study, the majority of patients with early Parkinson's disease who were receiving stable pramipexole IR treatment were successfully switched to pramipexole ER. Relative to placebo at week 18, pramipexole ER 0.375-4.5 mg (of the salt) once daily significantly decreased the sum of the UPDRS parts II and III subtotal scores from baseline in two trials in patients with early or advanced Parkinson's disease, and also reduced the percentage of off-time during waking hours in patients with advanced disease. The efficacy of pramipexole ER was maintained after 33 weeks of treatment in the trials in patients with early or advanced Parkinson's disease. Pramipexole ER was generally well tolerated in patients with Parkinson's disease, with the rate of adverse events being generally similar to that with pramipexole IR.

11. Sequential-release of anticancer drugs microcapsulated with ethylcellulose

顾耕华; 黄剑奇; 何虹

2002-01-01

Objective To approach the sequential release of antitumor drugs and promote the effect of chemotherapy.Methods Adriamycin (ADM) and carboplatin (CBP) were respectively microcapsulated with ethylcellulose by organic phase separation. The morphology and sizes of the microcapsules were observed and measured with light microscope and scanning electromicroscope. The contents and the release rates of ADM and CBP in microcapsules were measured with fluorescence spectrophotometer and high-efficiency phantom chromatic (HPC) spectrum respectively. The antitumor sensitivity test in vitro was devised with MTT assay.Results The microcapsules of ADM and CBP were spherical in shape with diameters of 196?4 μm and 214?8 μm respectively. The contents of one-layer and two-layer CBP and ADM microcapsules were 51.4%, 35.7% and 39.8% respectively, with the release rates in vitro of 62.4%/day, 54.8%/day and 48.2% /8h. The results of drug sensitivity test in vitro demonstrated that the current preparation has never affected the stability and antitumor activity of CBP and ADM.Conclusion Microcapsules with different drugs and different thickness of material have different release rate. Combined arterial chemoembolization with different microcapsules could approach the sequential release and promote the effect of chemotherapy.

12. Controlled release from recombinant polymers.

Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

2014-09-28

Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.

13. Nuclear energy release from fragmentation

Li, Cheng; Tsang, M B; Zhang, Feng-Shou

2015-01-01

Nuclear energy released by splitting Uranium and Thorium isotopes into two, three, four, up to eight fragments with nearly equal size are studied. We found that the energy released come from equally splitting the $^{235,238}$U and $^{230,232}$Th nuclei into to three fragments is largest. The statistical multifragmentation model is employed to calculate the probability of different breakup channels for the excited nuclei. Weighing the the probability distributions of fragments multiplicity at different excitation energies for the $^{238}$U nucleus, we found that an excitation energy between 1.2 and 2 MeV/u is optimal for the $^{235}$U, $^{238}$U, $^{230}$Th and $^{232}$Th nuclei to release nuclear energy of about 0.7-0.75 MeV/u.

14. Training Materials for Release 3

Wake, Jo Dugstad; Hansen, Cecilie; Debus, Kolja;

This document, D7.4 – training materials for release 3, provides an overview of the training material for version 3 of the NEXT-TELL tools and methods. Previous documents submitted as part of work package 7, which is about teacher training, are D7.1 – Training Concept, D7.2 – Training Materials...... for Release 1 and D7.3 – Training Materials for Release 2. D7.4 builds on D7.1 and D7.2 and D7.3. D7.4 contains further development of previous work within WP7, essentially a revised theoretical approach to the teacher training, and expansion of the notion of tool training. The media in use have been expanded...

15. Tritium and helium retention and release from irradiated beryllium

Anderl, R.A.; Longhurst, G.R.; Oates, M.A.; Pawelko, R.J. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States)

1998-01-01

This paper reports the results of an experimental effort to anneal irradiated beryllium specimens and characterize them for steam-chemical reactivity experiments. Fully-dense, consolidated powder metallurgy Be cylinders, irradiated in the EBR-II to a fast neutron (>0.1 MeV) fluence of {approx}6 x 10{sup 22} n/cm{sup 2}, were annealed at temperatures from 450degC to 1200degC. The releases of tritium and helium were measured during the heat-up phase and during the high-temperature anneals. These experiments revealed that, at 600degC and below, there was insignificant gas release. Tritium release at 700degC exhibited a delayed increase in the release rate, while the specimen was at 700degC. For anneal temperatures of 800degC and higher, tritium and helium release was concurrent and the release behavior was characterized by gas-burst peaks. Essentially all of the tritium and helium was released at temperatures of 1000degC and higher, whereas about 1/10 of the tritium was released during the anneals at 700degC and 800degC. Measurements were made to determine the bulk density, porosity and specific surface area for each specimen before and after annealing. These measurements indicated that annealing caused the irradiated Be to swell, by as much as 14% at 700degC and 56% at 1200degC. Kr gas adsorption measurements for samples annealed at 1000degC and 1200degC determined specific surface areas between 0.04 m{sup 2}/g and 0.1 m{sup 2}/g for these annealed specimens. The tritium and helium gas release measurements and the specific surface area measurements indicated that annealing of irradiated Be caused a porosity network to evolve and become surface-connected to relieve internal gas pressure. (author)

16. Evaporation rate of emulsion and oil-base emulsion pheromones

Knowledge of pheromone evaporation rate is critical to distribute pheromone containers effectively in the forest, orchard and field. There are several factors influencing the pheromone evaporation rate that include wind speed, container size and porosity, release area, temperature, humidity, pherom...

17. Simulated data supporting inbreeding rate estimates from incomplete pedigrees

U.S. Geological Survey, Department of the Interior — This data release includes: (1) The data from simulations used to illustrate the behavior of inbreeding rate estimators. Estimating inbreeding rates is particularly...

18. Prediction of modified release pharmacokinetics and pharmacodynamics from in vitro, immediate release, and intravenous data.

Lukacova, Viera; Woltosz, Walter S; Bolger, Michael B

2009-06-01

The aim of this study was to demonstrate the value of mechanistic simulations in gaining insight into the behaviors of modified release (MR) formulations in vivo and to use the properly calibrated models for prediction of pharmacokinetics (PK) and pharmacodynamics (PD). GastroPlus (Simulations Plus, Inc.) was used to fit mechanistic models for adinazolam and metoprolol that describe the absorption, PK, and PD after intravenous (i.v.) and immediate release (IR) oral (p.o.) administration. The fitted model for adinazolam was then used to predict the PD profile for a MR formulation and to design a new formulation with desired onset and duration of action. The fitted metoprolol model was used to gain insight and to explain the in vivo behaviors of MR formulations. For each drug, a single absorption/PK model was fitted that provided simulated plasma concentration-time profiles closely matching observed in vivo profiles across several different i.v. and p.o doses. Sedation score profiles of adinazolam were fitted with an indirect PD model. For metoprolol, the fitted absorption/PK model for IR p.o. doses was used to select in vitro dissolution conditions that best matched the in vivo release of MR doses. This model also explained differences in exposure after administration of MR formulations with different release rates. Mechanistic absorption/PK models allow for detailed descriptions of all processes affecting the two drugs' bioavailability, including release/dissolution, absorption, and intestinal and hepatic first pass extraction. The insights gained can be used to design formulations that more effectively overcome identified problems.

19. CONTROLLED RELEASE FROM PDMAEMA GELS PREPARED BY GAMMA RADIATION

Ning Liu; Min Yi; Shuang-ji Chen; Hong-fei Ha

2002-01-01

Poly(N,N-dimethylaminoethyl methacrylate) (polyDMAEMA) hydrogels prepared by γ-irradiation showed obvious temperature-sensitivity in a temperature range of 38-40℃ and pH-sensitivity at pH = 2.5. They also showed electric response behavior although it was not typical. The hydrogels were used in controlled release at different pH, temperature, and electric voltage. The release rates of methylene blue (MB) from the gels at 52℃ and pH = 1.24 were faster than those at 20℃ and pH = 10.56, respectively. In addition, the release rate at a field voltage of 5.0 was also faster than that without electric field.

20. Student Self-Assessment and Student Ratings of Teacher Rapport in Secondary Student Course Ratings

Roe, John Wilford

2010-01-01

This study involved administering two rating forms (student self-rating on commitment and student rating of teacher rapport) to approximately 1,400 secondary students taught by 12 different teachers at two different high school Latter-day Saint (LDS) released time seminaries along the Wasatch Front in Utah. Seminaries and Institutes of Religion…

1. Fluoride release from three glass ionomer materials and the effects of varnishing with or without finishing.

McKnight-Hanes, C; Whitford, G M

1992-01-01

The release rates of fluoride from discs made from three glass ionomer products, Miracle Mix (MM), Ketac-Silver (KS) and Ketac-Bond (KB), into artificial saliva for 3 weeks were determined. The discs were either not varnished, varnished or varnished and finished. The release rates were not proportional to the fluoride concentrations of the products and were ordered: MM > KB > KS. The rates declined sharply as a function of time regardless of the product or treatment. Varnishing the discs caused a reduction of 61-76% depending on the product. Finishing the varnished discs produced a significant increase in the fluoride release from MM but had no effect on the release from KS or KB. In a separate study with MM, it was determined that the release rate of fluoride was inversely proportional to the powder: liquid ratio used to prepare the discs.

2. Release Characteristics of Different N Forms in an Uncoated Slow/Controlled Release Compound Fertilizer

DONG Yan; WANG Zheng-yin

2007-01-01

This study examined the release characteristics of different N forms in an uncoated slow/controlled-release compound fertilizer (UCRF) and the N uptake and N-use efficiency by rice plants. Water dissolution, soil leaching, and pot experiments were employed. The dynamics of N release from the UCRF could be quantitatively described by three equations: the first-order kinetics equation [Nt = N0 (1-e-kt)], Elovich equation (Nt = a + blnt), and parabola equation (Nt = a + bt0.5), with the best fitting by the first-order kinetics equation for different N (r= 0.9569**-0.9999**). The release potentials (N0 values estimated by the first-order kinetics equation) of different N in the UCRF decreased in the order of total N ＞ DON ＞ urea-N ＞ NH4+-N ＞ NO3--N in water, and total N ＞ NH4+-N ＞ DON ＞ urea-N ＞ NO3--N in soil, respectively,being in accordance with cumulative amounts of N release. The constants of N release rate (k values and b values) for different N forms were in decreasing order of total N ＞ DON ＞ NH4+-N ＞ NO3--N in water, whereas the k values were urea-N ＞DON ＞ NH4+-N ＞ total N ＞ NO3--N, and the b values were total N ＞ NH4+-N ＞ DON ＞ NO3--N ＞ urea-N in soil. Compared with a common compound fertilizer, the N-use efficiency, N-agronomy efficiency, and N-physiological efficiency of the UCRF were increased by 11.4%, 8.32 kg kg-1, and 5.17 kg kg-1, respectively. The ratios of different N to total N in the UCRF showed significant correlation with N uptake by rice plants. The findings showed that the first-order kinetics equation [Nt=N0(1-e-kt)] could be used to describe the release characteristics of different N forms in the fertilizer. The UCRF containing different N forms was more effective in facilitating N uptake by rice compared with the common compound fertilizer containing single urea-N form.

3. EFFECT OF NATURAL AND SYNTHETIC POLYMER ON RELEASE OF KETOTIFEN FUMARATE MATRIX TABLETS: A SUSTAINED RELEASE DOSAGE FORM

Md. M. Rahman*, A. B. Ripon Khalipha , Md. A. K. Azad , MD. Z. Faruki , A. K. Chaurasiya and H. Hossain

2013-04-01

Full Text Available ABSTRACT: With the blend of Methocel K15, a synthetic polymer and xanthan gum, a natural polymer (3:1 was used in the formulation of matrix tablets to find out the effect of natural polymer in the sustained release dosage form. Direct compression process was applied for the preparation of Ketotifen fumarate tablets. The dissolution profiles were carried out by USP apparatus 2 (paddle at 50 rpm in 500 ml 0.1 N HCl and distilled water. For interpreting the results a one way analysis of variance (ANOVA was exploited. Statistically significant differences were found among the drug release profile from different matrices. At a higher polymeric content (60% of the total tablet weight, drug release from the combination of Methocel K15M and xanthan gum (3:1 was slower. On the contrary, at a lower polymeric level (30% of the total tablet weight; the rate of drug release was prominent. The best-fit release kinetics was accomplished with the Higuchi model followed by the zero-order plot, Korsmeyer and Hixson Crowell equations. One formulation showed drug release is more controlled. The data obtained proved that the formulations are useful for a sustained release of ketotifen fumarate. From these formulations corresponded more controlled of the drug release by the higher polymeric level of methocel K15M & xanthan gum and vice versa. The extended release of the model drug found from the higher proportion of methocel K15M and xanthan gum. As a result, the frequency of administration of such type of drug reduced.

4. 7 CFR 550.29 - Press releases.

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Press releases. 550.29 Section 550.29 Agriculture... Program Management § 550.29 Press releases. Press releases or other forms of public notification will be... opportunity to review, in advance, all written press releases and any other written information to be...

5. 28 CFR 2.83 - Release planning.

2010-07-01

... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Release planning. 2.83 Section 2.83... Release planning. (a) All grants of parole shall be conditioned on the development of a suitable release... parole date for purposes of release planning for up to 120 days without a hearing. If efforts to...

6. Lignin based controlled release coatings

Mulder, W.J.; Gosselink, R.J.A.; Vingerhoeds, M.H.; Harmsen, P.F.H.; Eastham, D.

2011-01-01

Urea is a commonly used fertilizer. Due to its high water-solubility, misuse easily leads to excess nitrogen levels in the soil. The aim of this research was to develop an economically feasible and biodegradable slow-release coating for urea. For this purpose, lignin was selected as coating material

7. Heparin release from thermosensitive hydrogels

Gutowska, Anna; Bae, You Han; Feijen, Jan; Kim, Sung Wan

1992-01-01

Thermosensitive hydrogels (TSH) were synthesized and investigated as heparin releasing polymers for the prevention of surface induced thrombosis. TSH were synthesized with N-isopropyl acrylamide (NiPAAm) copolymerized with butyl methacrylate (BMA) (hydrophobic) or acrylic acid (AAc) (hydrophilic) co

8. Flavor Release from French Fries

Loon, W.A.M.; Linssen, J.P.H.; Boelrijk, A.E.M.; Burgering, M.J.M.; Voragen, A.G.J.

2006-01-01

Flavor release from French fries was measured with the MS-NOSE using both panelists and a mouth-model system. The identity of several volatiles measured with the MS-NOSE was verified with MS-MS. The effect of frying time and the effect of adding salt on I-max (maximum intensity of compounds) and on

9. Spatial release from informational masking

2001-05-01

A new method for investigating spatial release from informational masking was developed and employed in two experiments. The new method is computer controlled and efficient. It employs the versatile coordinate response measure speech stimulus set [Bolia et al., J. Acoust. Soc. Am. 107, 1065 (2000)]. The experiments were conducted in an anechoic room, with a primary loudspeaker in front of the listener and a secondary loudspeaker at 60 deg to the right. Target messages were presented from the primary speaker only. For a standard, distractor messages, simultaneous with the target, were also presented from the primary speaker only. Spatial release was measured by presenting the distractors from both primary and secondary speakers with a temporal offset. Experiment 1 fixed the offset (secondary leading, +4 ms) and varied the number of distractors (1 to 3) and the target-to-distractor ratio (-12 to +4 dB). Masking release, sometimes as large as 10 dB, was found for all combinations of these variables. Experiment 2 varied the offset over a wide range of values. Substantial release from masking was found for both positive and negative offsets, but only in the range in which speech echoes are suppressed (<50 ms). [Work supported by NIDCD grant DC 00181.

10. Lignin based controlled release coatings

Mulder, W.J.; Gosselink, R.J.A.; Vingerhoeds, M.H.; Harmsen, P.F.H.; Eastham, D.

2011-01-01

Urea is a commonly used fertilizer. Due to its high water-solubility, misuse easily leads to excess nitrogen levels in the soil. The aim of this research was to develop an economically feasible and biodegradable slow-release coating for urea. For this purpose, lignin was selected as coating

11. Lignin based controlled release coatings

Mulder, W.J.; Gosselink, R.J.A.; Vingerhoeds, M.H.; Harmsen, P.F.H.; Eastham, D.

2011-01-01

Urea is a commonly used fertilizer. Due to its high water-solubility, misuse easily leads to excess nitrogen levels in the soil. The aim of this research was to develop an economically feasible and biodegradable slow-release coating for urea. For this purpose, lignin was selected as coating material

12. Release kinetics of coated, donut-shaped tablets for water soluble drugs.

Kim, C J

1999-02-01

Coated, donut-shaped tablets (CDST) were designed to achieve parabolic and linear drug release profiles. When rapidly erodible polymers (HPMC E3, HPC, PEG8000, PEOs (Mw=100000 and 200000)) were used, the release profiles of diltiazem HCl from the tablets becomes parabolic whereas zero-order release was achieved by using slowly erodible polymers (HPMC E5, HPMC E15, PEO (Mw=300000)). Drug release from the rapidly erodible polymers was governed by the pure erosion of the polymer while both polymer erosion and drug diffusion controlled drug release from the slowly erodible polymers. As drug loading was increased from 10% to 39% w/w, the drug release rate from CDST based on HPMC E3 became faster and parabolic whereas that from CDST based on HPMC E5 was linear. The slowly erodible polymer (HPMC E5) provided parabolic release profiles when drug loading was greater than 49% w/w. In this case, drug release mechanisms likely shifted from a combination of polymer erosion and drug diffusion to pure polymer erosion due to the enhancement of polymer erosion by faster influx of water. As drug solubility decreased from 61.6% w/v (diltiazem HCl), 1.0% w/v (theophylline), to 0.5% w/v (nicardipine HCl), the drug release rate from CDST based on HPMC E3 decreased due to polymer erosion mechanism but there was little difference in release rate from CDST based on HPMC E5 due to the greater contribution of drug diffusion to drug release kinetics along with polymer erosion. As expected, the drug release rate of diltiazem HCl from HPMC E3 and E5 was significantly influenced by stirring rate and hole size.

13. Modelling and simulations of controlled release fertilizer

Irfan, Sayed Ameenuddin; Razali, Radzuan; Shaari, Ku Zilati Ku; Mansor, Nurlidia

2016-11-01

The recent advancement in controlled release fertilizer has provided an alternative solution to the conventional urea, controlled release fertilizer has a good plant nutrient uptake they are environment friendly. To have an optimum plant intake of nutrients from controlled release fertilizer it is very essential to understand the release characteristics. A mathematical model is developed to predict the release characteristics from polymer coated granule. Numerical simulations are performed by varying the parameters radius of granule, soil water content and soil porosity to study their effect on fertilizer release. Understanding these parameters helps in the better design and improve the efficiency of controlled release fertilizer.

14. Aroma release and retronasal perception during and after consumption of flavored whey protein gels with different textures. 1. in vivo release analysis.

Mestres, Montserrat; Moran, Noelia; Jordan, Alfons; Buettner, Andrea

2005-01-26

The influence of gel texture on retronasal aroma release during mastication was followed by means of real-time proton-transfer reaction mass spectrometry and compared to sensory perception of overall aroma intensity. A clear correlation was found between individual-specific consumption patterns and the respective physicochemical release patterns in vivo. A modified data analysis approach was used to monitor the aroma changes during the mastication process. It was found that the temporal resolution of the release profile played an important role in adequate description of the release processes. On the basis of this observation, a hypothesis is presented for the observed differences in intensity rating.

15. A型肉毒杆菌毒素的壳聚糖／海藻酸钠缓释微囊研制和药物的体外释放速率研究%The Study In Vitro Release Rate Study of Botulinum Toxin type A Chitosan/Alginate Microcapsules Using Research and Drugs

吴河坪; 林小铭; 曾明兵; 陈静嫦

2015-01-01

目的：研制包裹A型肉毒杆菌毒素的壳聚糖/海藻酸钠微囊，并测定其体外药物释放动力学。方法：采用注射器滴注法制成包裹A型肉毒杆菌毒素的壳聚糖/海藻酸钠微囊混悬液。采用高效液相色谱法测定A型肉毒杆菌毒素的标准曲线，每隔2周测定微囊所包裹的A型肉毒杆菌毒素体外释放浓度。结果：微囊形态为圆形透明颗粒状，粒径在1mm左右。用SPSS统计软件进行分析微囊中A型肉毒杆菌毒素的体外每2周释放量，显示药物累积释放量与时间之间为直线关系，基本符合药物零级释放动力学。结论：滴注法制备包裹A型肉毒杆菌毒素的壳聚糖/海藻酸钠缓释微囊制作方法简便，其药物体外释放稳定。%Objective:To develop parcels of botulinum toxin type A chitosan/alginate and tested for in vitro drug release kinetics. Method:using a syringe infusion into the legal package botulinum toxin type A chitosan/alginate suspension. Determination of botu-linum A toxin standard curve, two weeks entrapped microcapsules measured botulinum toxin type A in vitro release every concentra-tion using high performance liquid chromatography. Results: The microcapsules form a circular transparent granular diameter of about 1mm. Using SPSS statistical software for analysis microcapsules A botulinum toxin in vitro release every two weeks, show cumu-lative drug release and the time between a linear relationship, in line with the zero-order release kinetics of drugs. Conclusion:chito-san infusion prepared package of botulinum toxin type A/alginate microcapsules using the production method is simple, its in vitro drug release and stability.

16. Mechanistic analysis of triamcinolone acetonide release from PLGA microspheres as a function of varying in vitro release conditions.

Doty, Amy C; Zhang, Ying; Weinstein, David G; Wang, Yan; Choi, Stephanie; Qu, Wen; Mittal, Sachin; Schwendeman, Steven P

2017-04-01

In vitro tests for controlled release PLGA microspheres in their current state often do not accurately predict in vivo performance of these products during formulation development. Here, we introduce a new mechanistic and multi-phase approach to more clearly understand in vitro-in vivo relationships, and describe the first "in vitro phase" with the model drug, triamcinolone acetonide (Tr-A). Two microsphere formulations encapsulating Tr-A were prepared from PLGAs of different molecular weights and end-capping (18kDa acid-capped and 54kDa ester-capped). In vitro release kinetics and the evidence for controlling mechanisms (i.e., erosion, diffusion, and water-mediated processes) were studied in four release media: PBST pH 7.4 (standard condition), PBST pH 6.5, PBS+1.0% triethyl citrate (TC), and HBST pH 7.4. The release mechanism in PBST was primarily polymer erosion-controlled as indicated by the similarity of release and mass loss kinetics. Release from the low MW PLGA was accelerated at low pH due to increased rate of hydrolysis and in the presence of the plasticizer TC due to slightly increased hydrolysis and much higher diffusion in the polymer matrix. TC also increased release from the high MW PLGA due to increased hydrolysis, erosion, and diffusion. This work demonstrates how in vitro conditions can be manipulated to change not only rates of drug release from PLGA microspheres but also the mechanism(s) by which release occurs. Follow-on studies in the next phases of this approach will utilize these results to compare the mechanistic data of the Tr-A/PLGA microsphere formulations developed here after recovery of microspheres in vivo. This new approach based on measuring mechanistic indicators of release in vitro and in vivo has the potential to design better, more predictive in vitro release tests for these formulations and potentially lead to mechanism-based in vitro-in vivo correlations. Copyright © 2016. Published by Elsevier B.V.

17. IN-VITRO RELEASE CHARACTERIZATION OF KETOROLAC TROMETHAMINE LOADED MATRIX TABLETS

Sayed Koushik Ahamed, Sujan Banik and Mohammad Salim Hossain*

2013-03-01

Full Text Available ABSTRACT: The present investigation highlighted the formulation and release characterization of Ketorolac Tromethamine loaded matrix tablet. Various formulations of tablets were prepared by direct compression method along with Kollidon SR and Hydroxy Propyl Methyl Cellulose (HPMC as release retardant polymers. Each of the formulated tablets contains 50mg Ketorolac Tromethamine. The evaluation involved physical properties studies (weight variation, thickness, length, width, hardness, friability, and drug content of tablets and in vitro release kinetics assessment. The USP paddle method was operated at 50 rpm selected to perform the dissolution test and 900 ml phosphate buffer of pH 7.4 was used as dissolution medium. The drug release from each formulation was analyzed by using release kinetics theories. All formulations followed Higuchi release kinetics. When the release data was plotted into Korsemeyer-Peppas equation, then it was confirmed that F-1 to F-5 exhibited fickian type drug release whereas F-6 exhibited non-Fickian type drug release. The in-vitro release studies revealed that the formulation F-4 can be taken as an ideal or optimized formulation of sustained release tablets. Furthermore, the dissolution of the formulation-4 was performed in SLS (1%, 1.5%, and 2% medium, which was observed gradually decreasing release rate as concentration of SLS medium increased.

18. In vitro study on sustained release capsule formulation of acetazolamide.

Pandey, V P; Kannan, K; Manavalan, R; Desai, N

2003-10-01

In the present study formulation of sustained release capsule of acetazolamide 250 mg was tried using nonpareil seeds. Nonpareil seeds were coated with drug, polyvinylpyrrolidone, glyceryl monostearate, microcrystalline wax, and glyceryl distearate either individually or in combination to achieve sustained release capsule 250 mg. In successful formulation 20% drug coated pellets and 80% wax coated pellets were taken. Wax coated pellets for successful formulation contained coating of microcrystalline wax and glyceryl distearate on drug coated pellets of the same concentration of 1.6% w/w. Successful formulated sustained release capsule 250 mg of acetazolamide was compared in in vitro study with theoretical sustained release formulation suggested by wagner and one marketed sustained release capsule 250 mg. Formulated capsule showed result superior to or on par with marketed capsule. For successful formulation pellets were filled in '1' size hard gelatin capsule and stability study was carried out in hot air over at room temperature and 45 degrees C for 5 weeks. The formulation was found stable in respect of drug content and release rate.

19. DEVELOPMENT OF SUSTAINED RELEASE TABLETS CONTAINING SOLID DISPERSIONS OF BACLOFEN

K. H. Janardhana

2013-12-01

Full Text Available Sustained release tablets containing solid dispersions granules of a poorly water soluble drug were prepared to investigate the controlled release of the drug. Baclofen was chosen because of its poor water solubility and short elimination half-life. Poloxamer 188 and PEG 6000 were used as solid dispersion carrier. Free flowing solid dispersion granules were prepared by adsorbing the melt of the drug and carriers onto the surface of an adsorbent, Carbopol 934P followed by direct compression with HPMC K4M and HPMC K100 to obtain an solid dispersion loaded sustained release tablets. FTIR studies confirmed that the compatibility of drug and carriers. Differential scanning calorimetry (DSC and X-ray diffraction (XRD revealed partially amorphous structures of the drug in solid dispersion granules. The solid dispersion granules dissolved completely within 30 min, which was much faster than that of pure drug baclofen. The sustained release of baclofen from the solid dispersion containing tablet was achieved for 2 h in gastric fluid (pH 1.2 and for up to 10 h in intestinal fluid (pH 6.8. A combination of solid dispersion techniques using adsorption and sustained release concepts is a promising approach to control the release rate of poorly water-soluble drugs.

20. DEVELOPMENT OF SUSTAINED RELEASE TABLETS CONTAINING SOLID DISPERSIONS OF BACLOFEN

K. H. Janardhana

2015-07-01

Full Text Available Sustained release tablets containing solid dispersions granules of a poorly water soluble drug were prepared to investigate the controlled release of the drug. Baclofen was chosen because of its poor water solubility and short elimination half-life. Poloxamer 188 and PEG 6000 were used as solid dispersion carrier. Free flowing solid dispersion granules were prepared by adsorbing the melt of the drug and carriers onto the surface of an adsorbent, Carbopol 934P followed by direct compression with HPMC K4M and HPMC K100 to obtain an solid dispersion loaded sustained release tablets. FTIR studies confirmed that the compatibility of drug and carriers. Differential scanning calorimetry (DSC and X-ray diffraction (XRD revealed partially amorphous structures of the drug in solid dispersion granules. The solid dispersion granules dissolved completely within 30 min, which was much faster than that of pure drug baclofen. The sustained release of baclofen from the solid dispersion containing tablet was achieved for 2 h in gastric fluid (pH 1.2 and for up to 10 h in intestinal fluid (pH 6.8. A combination of solid dispersion techniques using adsorption and sustained release concepts is a promising approach to control the release rate of poorly water-soluble drugs.

1. Evaluation of the Thermosensitive Release Properties of Microspheres Containing an Agrochemical Compound.

Terada, Takatoshi; Ohtsubo, Toshiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

2017-01-01

The purpose of this study was to develop a deeper understanding of the key physicochemical parameters involved in the release profiles of microsphere-encapsulated agrochemicals at different temperatures. Microspheres consisting of different polyurethanes (PUs) were prepared using our previously reported solventless microencapsulation technique. Notably, these microspheres exhibited considerable differences in their thermodynamic characteristics, including their glass transition temperature (Tg), extrapolated onset temperature (To) and extrapolated end temperature (Te). At test temperatures below the To of the PU, only 5-10% of the agrochemical was rapidly released from the microspheres within 1 d, and none was released thereafter. However, at test temperatures above the To of the PU, the rate of agrochemical release gradually increased with increasing temperatures, and the rate of release from the microspheres was dependent on the composition of the PU. Taken together, these results show that the release profiles of the microspheres were dependent on their thermodynamic characteristics and changes in their PU composition.

2. Predicting release and transport of pesticides from a granular formulation during unsaturated diffusion in porous media

Paradelo Pérez, Marcos; Soto-Gómez, Diego; Pérez-Rodrígez, Paula

2014-01-01

The release and transport of active ingredients (AIs) from controlled-release formulations (CRFs) have potential to reduce groundwater pesticide pollution. These formulations have a major effect on the release rate and subsequent transport to groundwater. Therefore the influence of CRFs should...... be included in modeling non-point source pollution by pesticides. We propose a simplified approach that uses a phase transition equation coupled to the diffusion equation that describes the release rate of AIs from commercial CRFs in porous media; the parameters are as follows: a release coefficient......, the solubility of the AI, and diffusion transport with decay. The model gives acceptable predictions of the pesticides release from commercial CRFs in diffusion cells filled with quartz sand. This approach can be used to study the dynamics of the CRF-porous media interaction. It also could be implemented in fate...

3. Release behavior of copper ion in a novel contraceptive composite.

Li, Juan; Suo, Jinping; Huang, Xunbin; Ye, Chang; Wu, Xiwang

2007-09-01

The universally used contraceptive method, the Cu-IUD, an effective contraceptive, is being increasingly used worldwide for family planning. To avoid abnormal bleeding, pain, partial and complete expulsion associated with the burst release of copper during the first few days, a novel cross-linked composite based on poly vinyl alcohol (PVA) that contains copper ions, but not metallic copper, was synthesized. PVA, well known for its good processability, high strength, long-term temperature and pH stability and biocompatibility, was used as the matrix material. The corrosion products and the release rate of copper ions after soaking in simulated body fluid (SBF) for different time spans were studied by environmental scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction and atomic absorption spectrophotometer. No significant change on time dependence for the release rate of copper ions in the composite compared with that of metallic copper was found. Moreover, no other new elements, such as P, Cl and Ca, appeared on the surface of the composite and no Cu(2)O formed after immersing in SBF for 90 days. Burst release of copper ions can be avoided by loading copper ions in this polymer material. Release channels would not be obstructed by the deposition of corrosion products and nearly all of the copper loaded in the composites could be an effective contraceptive.

4. Hazardous animal waste carcasses transformation into slow release fertilizers.

Sharrock, Patrick; Fiallo, Marina; Nzihou, Ange; Chkir, Mouna

2009-08-15

Because of the need to address disposal of materials infected with pathogens new regulations have come into effect for the transport and disposal of dead farm animals or carcasses. For precautionary reasons, disposal to landfill, composting, biogas generation or fertilizer use are banned recycling paths because of incomplete knowledge about contamination transmission paths. Thermal treatment is recognized as a safe elimination process. Animal wastes have a high calorific value (above 16 MJ/kg). However, combustion of the organics leaves mineral residues (near 30%). The ashes contain mostly calcium and phosphate with some sodium, potassium and magnesium. We have examined the transformation of the ashes into a slow release fertilizer. We used a mixture of acids to partly dissolve the combustion residues and form slurry. In a second step, base was added to neutralize and solidify the reaction mixture. The final product was a whitish polycrystalline solid. Leaching tests were made to evaluate the nutrient release rate in laboratory columns. Water leachates were analyzed for up to ten pore-bed volumes and showed, as expected, large differences in release rates. Nitrate release was slowed and phosphate did not level even after ten pore-bed volumes. This demonstrates that insoluble precipitates (gypsum) contribute to control soluble ion release.

5. Controlled Release Formulations of Auxinic Herbicides

Kowalski, Witold J.; Siłowiecki, Andrzej.; Romanowska, Iwona; Glazek, Mariola; Bajor, Justyna; Cieciwa, Katarzyna; Rychter, Piotr

2013-04-01

ingredient in the HBA oligomers was chemically bound to the oligomer matrix and a controlled release followed in concert with the hydrolysis of ester bonds in the oligomer systems. Due to the high volatility and high water solubility of the DMA salts, significant amounts of active ingredients were predisposed to be dispersed in the environment. On the other hand, the HBA oligomers exhibit low volatility and low solubility in water, so they tend to exhibit lover migrating rates from the target site. The obtained plots suggested that in the case of the HBA oligomers the effectiveness were delayed in time when compared with the DMA salts. The integral effectiveness of the studied HBA oligomers was practically equivalent to the conventional DMA salts, but the release of the HBA herbicides was delayed in time vs. DMA salts. The mixtures of oligo (R,S)-3-hydroxybutyric acid containing chemically bonded 2,4-D, Dicamba and MCPA (HBA) were proposed as carriers of active ingredients that could be released to control the sensitive weeds. The synthesized HBA oligomers could be particularly useful in a number of practical applications, because they release the herbicide to plants at a controlled rate and in amounts required over a specified period of time, their degradation products are identical to metabolites formed in plant cells, the physicochemical and operational parameters of the carrier oligomers might be optimized by fine-tuning of synthesis conditions. The decreased vapor pressure and increased lipophilicity of the studied materials could reduce the risk exposure of the operational personnel, as well as, a decrease the environmental pollution. Acknowledgments The authors would like to thank the Polish Ministry of Science and Higher Education for supporting this work through the grant No. NN 310 303039. References [1] S. Dubey, V. Jhelum, P.K. Patanjali, Controlled release agrochemical formulations: A review, J. Scientific &Industrial Research (India) 70 (2011) 105-112. [2] W. J

6. Studies on pectins as potential hydrogel matrices for controlled-release drug delivery.

Sungthongjeen, S; Pitaksuteepong, T; Somsiri, A; Sriamornsak, P

1999-12-01

Polymeric hydrogels are widely used as controlled-release matrix tablets. In the present study, we investigated high-methoxy pectins for their potential value in controlled-release matrix formulations. The effects of compression force, ratio of drug to pectin, and type of pectin on drug release from matrix tablets were also investigated. The results of the in vitro release studies show that the drug release from compressed matrix tablets prepared from pectin can be modified by changing the amount and the type of pectin in the matrix tablets. However, compression force did not significantly affect the drug release. The mechanisms controlling release rate were discussed with respect to drug diffusion through the polymer matrices, but may be more complex.

7. Stabilization and release of enzymes from silk films.

Lu, Qiang; Wang, Xiaoqin; Hu, Xiao; Cebe, Peggy; Omenetto, Fiorenzo; Kaplan, David L

2010-04-08

A significant challenge remains to protect protein drugs from inactivation during production, storage, and use. In the present study, the stabilization and release of horseradish peroxidase (HRP) in silk films was investigated. Water-insoluble silk films were prepared under mild aqueous conditions, maintaining the activity of the entrapped enzyme. Depending on film processing and post-processing conditions, HRP retained more than 90% of the initial activity at 4 degrees C, room temperature and 37 degrees C over two months. The stability of protein drugs in silk films is attributed to intermolecular interactions between the silk and the enzymes, based on Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The unique structural feature of silk molecules, periodic hydrophobic-hydrophilic domains, enabled strong interactions with proteins. The entrapped protein was present in two states, untrapped active and trapped inactive forms. The ratio between the two forms varied according to processing conditions. Proteolytic degradation and dissolution of the silk films resulted in the release of the bound enzyme which was otherwise not released by diffusion; enzyme recovered full activity upon release. There was a linear relationship between silk degradation/dissolution and the release of entrapped enzyme. Modifying the secondary structure of the silk matrix and the interactions with the non-crystalline domains resulted in control of the film degradation or dissolution rate, and therefore the release rate of the entrapped enzyme. Based on the above results, silk materials are an intriguing carrier for proteins in terms of both retention of activity and controllable release kinetics from the films.

8. Physical insights into salicylic acid release from poly(anhydrides).

Dasgupta, Queeny; Chatterjee, Kaushik; Madras, Giridhar

2016-01-21

Salicylic acid (SA) based biodegradable polyanhydrides (PAHs) are of great interest for drug delivery in a variety of diseases and disorders owing to the multi-utility of SA. There is a need for the design of SA-based PAHs for tunable drug release, optimized for the treatment of different diseases. In this study, we devised a simple strategy for tuning the release properties and erosion kinetics of a family of PAHs. PAHs incorporating SA were derived from related aliphatic diacids, varying only in the chain length, and prepared by simple melt condensation polymerization. Upon hydrolysis induced erosion, the polymer degrades into cytocompatible products, including the incorporated bioactive SA and diacid. The degradation follows first order kinetics with the rate constant varying by nearly 25 times between the PAH obtained with adipic acid and that with dodecanedioic acid. The release profiles have been tailored from 100% to 50% SA release in 7 days across the different PAHs. The release rate constants of these semi-crystalline, surface eroding PAHs decreased almost linearly with an increase in the diacid chain length, and varied by nearly 40 times between adipic acid and dodecanedioic acid PAH. The degradation products with SA concentration in the range of 30-350 ppm were used to assess cytocompatibility and showed no cytotoxicity to HeLa cells. This particular strategy is expected to (a) enable synthesis of application specific PAHs with tunable erosion and release profiles; (b) encompass a large number of drugs that may be incorporated into the PAH matrix. Such a strategy can potentially be extended to the controlled release of other drugs that may be incorporated into the PAH backbone and has important implications for the rational design of drug eluting bioactive polymers.

9. Cumulative release characteristics of controlled-release nitrogen and potassium fertilizers and their effects on soil fertility, and cotton growth

Xiuyi Yang; Jibiao Geng; Chengliang Li; Min Zhang; Xiaofei Tian

2016-01-01

To investigate the interacting effects of polymer coated urea (PCU) and polymer coated potassium chloride (PCPC) on cotton growth, an experiment was conducted with containerized plants in 2014 and 2015. There were two kinds of nitrogen fertilizer, PCU and urea, which were combined with PCPC at three application rates (40, 80 and 120 kg ha−1). The kinds of nitrogen fertilizer formed the main plot, while individual rates of PCPC were the subplots. The results suggested N and K release patterns ...

10. Cumulative release characteristics of controlled-release nitrogen and potassium fertilizers and their effects on soil fertility, and cotton growth

Xiuyi Yang; Jibiao Geng; Chengliang Li; Min Zhang; Xiaofei Tian

2016-01-01

To investigate the interacting effects of polymer coated urea (PCU) and polymer coated potassium chloride (PCPC) on cotton growth, an experiment was conducted with containerized plants in 2014 and 2015. There were two kinds of nitrogen fertilizer, PCU and urea, which were combined with PCPC at three application rates (40, 80 and 120 kg ha−1). The kinds of nitrogen fertilizer formed the main plot, while individual rates of PCPC were the subplots. The results suggested N and K release patterns ...

11. The Reshock and Release Waves in PTFE

Karakhanov, S. M.; Bordzilovsky, S. A.

1999-06-01

To study the deformation and destruction of PTFE polymer the specimens were loaded by the complex wave structure: shock, reshock and release wave. The transmitted stress-time profiles were recorded with the manganin gages. The Lagrange analysis of stress histories gave the stress-volume paths during reshock loading and unloading of PTFE in the stress range of 10 to 35 GPa. The data revealed the viscoelastic behavior typical for polymers. For a single shock loading the relaxation zone with the duration of about 0.3 μs was noticeable behind the first stress jump. The reshock-release stress pulse that started from the state behind the first shock attenuated with the rate greater than in hydrodynamic approximation. The correlation was noticed between the stress-time and electrical resistivity-time profiles in the relaxation zone. The reloading-unloading stress hysteresis gave the possibility to measure the critical shear stress (τ) in a shocked state. The data showed the decrease in τ at higher stresses. The authors suggested that the most probable mechanism of destruction of PTFE in the studied region of pressures and temperatures is thermodestruction of a polymer chain by the thermal fluctuations under load.

12. FORMULATION AND EVALUATION OF DICLOFENAC CONTROLLED RELEASE TABLETS EMPLOYING OLIBANUM RESIN

K.P.R. Chowdary and G. Rami Reddy *

2012-04-01

Full Text Available The objective of the study is to evaluate Olibanum resin, a natural resin polymer as matrix polymer for controlled release tablets and to design matrix tablets of diclofenac for controlled release. Matrix tablets of diclofenac were formulated employing Olibanum resin in different proportions of drug and polymer and the tablets were evaluated for drug release kinetics and mechanism .Two diluents namely lactose (water soluble and DCP (water insoluble were included in the formulations to assess their influence on drug release characteristics of olibanum resin matrix tablets. Matrix tablets were found t¬o be non- disint-egrating in water, acidic (pH 1.2 and alkaline (pH 7.4 fluids and were considered suitable for oral controlled release. Diclofenac release from the matrix tablets formulated was slow and spread over 24 h and depended on the concentration (% of olibanum resin in the matrix tablets and nature/type of diluent. As the concentration of olibanum resin in the matrix tablets was increased, drug release was decreased. Release was relatively faster with water soluble diluent lactose when compared to water insoluble diluent DCP at all concentrations of olibanum resin. Drug release from the tablets followed first order kinetics and followed non - Fickian (anomalous diffusion release mechanism. Good linear relationships were observed between percent polymer and release rate in each case. The results of the study thus indicated olibanum resin could be used as rate controlling matrix in design of controlled release tablets. Both water soluble and water insoluble diluents can be included in the olibanum resin matrix tablets without affecting its rate controlling efficiency. Matrix tablets formulated employing olibanum resin(DF2 are considered suitable for controlled release of diclofenac over 24 h (i.e. once-a-day administration.

13. 14 CFR 125.373 - Original flight release or amendment of flight release.

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Original flight release or amendment of flight release. 125.373 Section 125.373 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... Flight Release Rules § 125.373 Original flight release or amendment of flight release. (a) A...

14. [Evolution of oral drug forms of metoprolol: advantages of long acting modified release forms with modified release].

Leonova, M V; Maneshina, O A; Belousov, Iu B

2010-01-01

Review oral modified release drug forms of beta-adrenoblocker metoprolol which is used in arterial hypertension and ischemic heart disease is presented. Metoprolol has salts such as tartrate which is used for production of immediate release (IR) and sustained release (SR) forms and succinate used for production of controlled release form (CR/XL). Metoprolol SR has monolith matrix type, metoprolol CR/XL-system of multiple pellets. Effect of metoprolol tartrate (IR) on mortality was demonstrated in a number of studies in patients with arterial hypertension (AH) (MAPHY), myocardial infarction (SMT, GMT, MIAMI), dilated cardiomyopathy and heart failure (MDC). Studies of efficacy of metoprolol SR are scarce. Antihypertensive efficacy of metoprolol SR in patients with AH did not exceed that of a metoprolol IR or CR/XL. First retrospective analysis of efficacy of metoprolol tartrate and succinate (CR/XL) in patients after myocardial infarction allowed to obtain comparable results of 34% mortality lowering. In a prospective study in patients with chronic heart failure (COMET) metoprolol tartrate IR was not superior to carvedilol when mortality lowering was concerned. At the same time administration of controlled release metoprolol (CR/XL) in 2 large clinical trials (RESOLVD, MERITAHF) was advantageous in patients with chronic heart failure relative to lowering of mortality and rate of hospitalizations. A novel controlled release form of metoprolol has been created as a tartrate salt on the basis of pellet technology (CD/ERT) and its bioequivalence to metoprolol CR/XL has been proved.

15. Microwave Activation of Drug Release

Jónasson, Sævar Þór

Due to current limitations in control of pharmaceutical drug release in the body along with increasing medicine use, methods of externally-controlled drug release are of high interest. In this thesis, the use of microwaves is proposed as a technique with the purpose of externally activating...... setup, called the microwave activation system has been developed and tested on a body phantom that emulates the human torso. The system presented in this thesis, operates unobtrusively, i.e. without physically interfering with the target (patient). The torso phantom is a simple dual-layered cylindrical...... the phantom is of interest for disclosing essential information about the limitations of the concept, the phantom and the system. For these purposes, a twofold operation of the microwave activation system was performed, which are reciprocal of each other. In the first operation phase, named mapping...

16. Zegerid--immediate-release omeprazole.

2005-04-11

The FDA has approved marketing of Zegerid powder for oral suspension (Santarus), an immediate-release formulation of the proton-pump inhibitor (PPI) omeprazole (Prilosec, and others). All other oral PPIs are delayed-release, enteric-coated formulations designed to prevent degradation of the drug by gastric acid. Each 20- or 40-mg packet of Zegerid contains 1680 mg sodium bicarbonate, which protects the drug from gastric acid degradation. A dose of Zegerid contains 460 mg of sodium, which may be excessive for some patients. Zegerid is the first oral PPI to be approved by the FDA for reduction of risk of upper GI bleeding in critically ill patients. The drug may be useful for patients who are unable to swallow and have nasogastric (NG) tubes in place. Zegerid cost $70.00 for 14 days' treatment, compared to less than$10 for 14 tablets of Prilosec OTC.

17. Neutron-absorber release device

VAN Erp, Jan B.; Kimont, Edward L.

1976-01-01

A resettable device is provided for supporting an object, sensing when an environment reaches a critical temperature and releasing the object when the critical temperature is reached. It includes a flexible container having a material inside with a melting point at the critical temperature. The object's weight is supported by the solid material which gives rigidity to the container until the critical temperature is reached at which point the material in the container melts. The flexible container with the now fluid material inside has insufficient strength to support the object which is thereby released. Biasing means forces the container back to its original shape so that when the temperature falls below the melting temperature the material again solidifies, and the object may again be supported by the device.

18. China's First Luxury Brands Released

Richard Zhu

2011-01-01

@@ China now has its own luxury brands.The four brands Feitian (Moutai spirit), Yong-Qi Zitan (furniture), Rongbaozhai (works of art) and Dongding Oolong (tea) were released as the first Chinese luxury brands by the China Luxury Institute on Nov.11.Based on the Institute's investigation of over 500 enterprises and brands within over 30 kinds of industries like garments, tea, wine, china and jade, in combination with market questionnaire, the first four brands have made their debut.

19. Controlled release of insect sex pheromones from paraffin wax and emulsions.

Atterholt, C A; Delwiche, M J; Rice, R E; Krochta, J M

1999-02-22

Paraffin wax and aqueous paraffin emulsions can be used as controlled release carriers for insect sex pheromones for mating disruption of orchard pests. Paraffin can be applied at ambient temperature as an aqueous emulsion, adheres to tree bark or foliage, releases pheromone for an extended period of time, and will slowly erode from bark and biodegrade in soil. Pheromone emulsions can be applied with simple spray equipment. Pheromone release-rates from paraffin were measured in laboratory flow-cell experiments. Pheromone was trapped from an air stream with an adsorbent, eluted periodically, and quantified by gas chromatography. Pheromone release from paraffin was partition-controlled, providing a constant (zero-order) release rate. A typical paraffin emulsion consisted of 30% paraffin, 4% pheromone, 4% soy oil, 1% vitamin E, 2% emulsifier, and the balance water. Soy oil and vitamin E acted as volatility suppressants. A constant release of oriental fruit moth pheromone from paraffin emulsions was observed in the laboratory for more than 100 days at 27 degreesC, with release-rates ranging from 0.4 to 2 mg/day, depending on the concentration and surface area of the dried emulsion. The use of paraffin emulsions is a viable method for direct application of insect pheromones for mating disruption. Sprayable formulations can be designed to release insect pheromones to the environment at a rate necessary for insect control by mating disruption. At temperatures below 38 degreesC, zero-order release was observed. At 38 degreesC and higher, pheromone oxidation occurred. A partition-controlled release mechanism was supported by a zero-order pheromone release-rate, low air/wax partition coefficients, and pheromone solubility in paraffin.

20. Colloid Release From Differently Managed Loess Soil

Vendelboe, Anders Lindblad; Schjønning, Per; Møldrup, Per

2012-01-01

of the total clay not associated with organic matter. No significant difference in release rate was found for air-dry aggregates. The low-carbon soils initially had a higher content of WSA but were more susceptible to disaggregation than the high-carbon soils. Furthermore, the application of NPK fertilizer had......The content of water-dispersible colloids (WDC) in a soil can have a major impact on soil functions, such as permeability to water and air, and on soil strength, which can impair soil fertility and workability. In addition, the content of WDC in the soil may increase the risk of nutrient loss...... and of colloid-facilitated transport of strongly sorbing compounds. In the present study, soils from the Bad Lauchsta¨dt longterm static fertilizer experiment with different management histories were investigated to relate basic soil properties to the content of WDC, the content of water-stable aggregates (WSA...

1. Surveillance of Diversion and Nonmedical Use of Extended-Release Prescription Amphetamine and Oral Methylphenidate in the United States

Sembower, Mark A.; Ertischek, Michelle D.; Buchholtz, Chloe; Dasgupta, Nabarun; Schnoll, Sidney H.

2013-01-01

This article examines rates of nonmedical use and diversion of extended-release amphetamine and extended-release oral methylphenidate in the United States. Prescription dispensing data were sourced from retail pharmacies. Nonmedical use data were collected from the Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS) System Drug Diversion Program and Poison Center Program. Drug diversion trends nearly overlapped for extended-release amphetamine and extended-release oral met...

2. Fabrication of drug eluting implants: study of drug release mechanism from titanium dioxide nanotubes

Hamlekhan, Azhang; Sinha-Ray, Suman; Takoudis, Christos; Mathew, Mathew T.; Sukotjo, Cortino; Yarin, Alexander L.; Shokuhfar, Tolou

2015-06-01

Formation of titanium dioxide nanotubes (TNTs) on a titanium surface holds great potential for promoting desirable cellular response. However, prolongation of drug release from these nano-reservoirs remains to be a challenge. In our previous work TNTs were successfully loaded with a drug. In this study the effect of TNTs dimensions on prolongation of drug release is quantified aiming at the introduction of a simple novel technique which overcomes complications of previously introduced methods. Different groups of TNTs with different lengths and diameters are fabricated. Samples are loaded with a model drug and rate of drug release over time is monitored. The relation of the drug release rate to the TNT dimensions (diameter, length, aspect ratio and volume) is established. The results show that an increase in any of these parameters increases the duration of the release process. However, the strongest parameter affecting the drug release is the aspect ratio. In fact, TNTs with higher aspect ratios release drug slower. It is revealed that drug release from TNT is a diffusion-limited process. Assuming that diffusion of drug in (Phosphate-Buffered Saline) PBS follows one-dimensional Fick’s law, the theoretical predictions for drug release profile is compatible with our experimental data for release from a single TNT.

3. Macula densa sensing and signaling mechanisms of renin release.

Peti-Peterdi, János; Harris, Raymond C

2010-07-01

Macula densa cells in the distal nephron, according to the classic paradigm, are salt sensors that generate paracrine chemical signals in the juxtaglomerular apparatus to control vital kidney functions, including renal blood flow, glomerular filtration, and renin release. Renin is the rate-limiting step in the activation of the renin-angiotensin system, a key modulator of body fluid homeostasis. Here, we discuss recent advances in understanding macula densa sensing and suggest these cells, in addition to salt, also sense various chemical and metabolic signals in the tubular environment that directly trigger renin release.

4. Measurements of fuel-N release during solid fuel combustion

G. Di Nola; H. Spliethoff; S. Leiser; W. van de Kamp [Delft University of Technology, Delft (Netherlands). Thermal Power Engineering Section

2003-07-01

A South American high volatile bituminous coal and two fuel blends obtained by adding 10% cocoa shells and 10% wood, respectively, were selected to investigate the release of fuel nitrogen during devolatilisation and the char burnout behavior. The chars were produced at atmospheric pressure in heated wire mesh (HWM) and isothermal plug flow (IPFR) reactors and subsequently compared for their fuel-N content. Char burnout behavior was investigated comparing data from IPFR with outputs of a thermogravimetric analyzer (TGA). Results showed that the volatile release yield was more affected by the final temperature and the residence time rather than by the heating rate. Fuel nitrogen release occurred to be particularly influenced by the residence time, showing higher total yields in the HWM with longer hold times at peak temperature. The comparison of char combustion rates in the IPFR and TGA showed that the data gained using a TGA is quantitatively not representative for combustion rates found in an industrial boiler. Combustion rates determined with the TGA are approximately three orders of magnitude lower than those determined with the IPFR. However, it was shown that differences in the combustion rates of the different fuels are reproducible qualitatively with both approaches. 27 refs., 10 figs., 3 tabs.

5. Percutaneous Release of the First Dorsal Extensor Compartment: A Cadaver Study

Güleç, Ali; Türkmen, Faik; Toker, Serdar

2016-01-01

Background: To evaluate the efficiency of the percutaneous 18-G needle technique in releasing the fibro-osseous sheath over the first dorsal extensor compartment of the hand. Methods: Using anatomic landmarks, percutaneous release was performed with an 18-G needle on 48 wrists of 24 cadavers. The specimens were then dissected and examined for the completeness of the first dorsal extensor compartment release and any tendon or neurovascular injuries. The tunnel length, number of abductor pollicis longus and extensor pollicis brevis tendons, presence of an intertendinous septum, and the effects of these parameters on percutaneous release were evaluated. Results: Percutaneous release was performed on all of the wrists, and the evaluation of the adequacy of release revealed 25 complete releases, 21 partial releases, and 2 missed releases. There were 19 cases of tendon complications. No neurovascular injuries were noted. The mean tunnel length was 2.66 ± 30 cm, and the mean number of tendons was 2.75 ± 0.86. A septum was present in 33.3% of cases. Tunnel length and tendon number had no statistically significant effect on release, whereas the presence of a septum was significantly associated with inadequate tunnel release and the development of tendon complications. Conclusions: Percutaneous release of the first dorsal extensor compartment using an 18-G needle was associated with high rates of incomplete release and tendon damage in the presence of an intertendinous septum. Further study is required under ultrasound guidance to determine the usefulness of percutaneous release in the first dorsal extensor compartment. Clinical Relevance: Release with a percutaneous needle tip in De Quervain’s syndrome may provide the advantages of better cosmetic results with less scar formation and an early return to work. PMID:27826460

6. Sustained-release naltrexone for opioid dependence.

Lobmaier, P; Kornør, H; Kunøe, N; Bjørndal, A

2008-04-16

Naltrexone is an opioid antagonist which effectively blocks heroin effects. Since opioid dependence treatment with naltrexone tablets suffers from high dropout rates, several depot injections and implants are under investigation. Sustained-release formulations are claimed to be effective, but a systematic review of the literature is lacking. To evaluate the effectiveness of sustained-release naltrexone for opioid dependence and its adverse effects in different study populations. The following databases were searched from their inception to November 2007: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, LILACS, PsycINFO, ISI Web of Science, trial database at http://clinicaltrials.gov, available NIDA monographs, CPDD and AAAP conference proceedings. The reference lists of identified studies, published reviews and relevant web sides were searched manually. Study authors and drug companies were contacted to obtain any unpublished material or missing data. To evaluate effectiveness only RCTs were included. To evaluate safety, any clinical trial reporting adverse effects was assessed. Treatment condition was extended to include alcohol dependent subjects and healthy volunteers. Reviewers independently evaluated the reports, rated methodological quality and extracted data. Analyses were performed separately for opioid dependent, alcohol dependent and healthy participants. Foe effectiveness, one report met inclusion criteria. Two dosages of naltrexone depot injections (192 and 384 mg) were compared to placebo. High-dose significantly increased days in treatment compared to placebo (WMD 21.00, 95% CI 10.68 to 31.32, p<0.0001). High-dose compared to low-dose significantly increased days in treatment (WMD 12.00, 95% CI 1.69 to 22.31, p=0.02). Number of patients retained in treatment did not show significant differences between groups. For adverse effects, seventeen reports met inclusion criteria analyses, six were RCTs. Side effects were significantly

Dasgupta, Queeny; Chatterjee, Kaushik; Madras, Giridhar

2015-09-08

The purpose of this work was to develop a family of cross-linked poly(xylitol adipate salicylate)s with a wide range of tunable release properties for delivering pharmacologically active salicylic acid. The synthesis parameters and release conditions were varied to modulate polyester properties and to understand the mechanism of release. Varying release rates were obtained upon longer curing (35% in the noncured polymer to 10% in the cured polymer in 7 days). Differential salicylic acid loading led to the synthesis of polymers with variable cross-linking and the release could be tuned (100% release for the lowest loading to 30% in the highest loading). Controlled release was monitored by changing various factors, and the release profiles were dependent on the stoichiometric composition, pH, curing time, and presence of enzyme. The polymer released a combination of salicylic acid and disalicylic acid, and the released products were found to be nontoxic. Minimal hemolysis and platelet activation indicated good blood compatibility. These polymers qualify as "bioactive" and "resorbable" and can, therefore, find applications as immunomodulatory resorbable biomaterials with tunable release properties.

8. Effect of ethanol on the release of morphine sulfate from Oramorph SR tablets.

Barkin, Robert L; Shirazi, Dean; Kinzler, Eric

2009-01-01

Recent data have shown that rapid release of active drug (i.e., dose-dumping) can occur when modified-release formulations of pain medications, and other extended-release pharmacotherapies, are exposed to ethanol in vitro. Dose-dumping of sustained-release opioids is of particular concern because of the risk for serious and potentially fatal adverse events. Sustained-release morphine sulfate tablets (Oramorph SR, 15, 30, 60, and 100 mg; Xanodyne Pharmaceuticals, Inc., Newport, KY) were incubated in vitro at simulated physiologic conditions in media containing no ethanol or ethanol in concentrations ranging from 4%-40% v/v. Morphine sulfate release was measured over the course of 1 to 24 hours using a high-performance liquid chromatography method (United States Pharmacopeia). The sustained-release morphine sulfate tablets exhibited no evidence of active drug dose-dumping. Regardless of ethanol concentration, ethanol exposure did not increase the rate of release of morphine sulfate. Release of approximately 20%-25% of the morphine sulfate dose within 1 hour was consistent among the morphine doses tested and ethanol concentrations. Release of morphine sulfate from the 60- and 100-mg tablets exposed to the higher ethanol concentrations (20% and 40% ethanol) was slightly delayed at all time points beyond 1 hour. The results of this in vitro study suggest that ethanol concentrations as high as 40% do not substantially alter the sustained-release properties of the morphine sulfate tablets.

9. Influence of dental biofilm on release of mercury from amalgam exposed to carbamide peroxide.

Steinberg, Doron; Blank, Ori; Rotstein, Ilan

2003-10-15

Tooth bleaching is a popular procedure in modern aesthetic dentistry. Bleaching agents may affect amalgam restorations by altering the release of mercury. The aim of this study was to explore the effect of biofilm-coated amalgam restorations on the release of mercury in the presence of carbamide peroxide. Samples of SDI and Valliant amalgams were submerged for either 14 days or 7 months in buffered KCl after which they were coated with saliva, bacteria, and polysaccharides. The samples were exposed to 10% carbamide peroxide (CP) for 24 h. The amount of mercury released was examined for 120 h. Results showed that most of mercury release occurred within the first 24 h, after which the release rate decreased sharply. After 120 h the release of mercury from the tested samples was minimal and similar to the control group. The presence of biofilm coating on the amalgam samples did not induce the release of mercury but tended to reduce mercury release into the surrounding environment. CP induces the release of mercury from amalgam samples. However, the presence of biofilm did not prevent large amounts of mercury release from amalgam coated with biofilms and exposed to CP. This study indicates that dental biofilm may retard the release of mercury from amalgam restorations.

10. Kinetics of piroxicam release from low-methylated pectin/zein hydrogel microspheres

The kinetics of a model drug (piroxicam) release from pectin/zein hydrogel microspheres was studied under conditions simulating the gastrointestinal tract. It is established that the rate-limiting step in the release mechanism is drug diffusion out of the microspheres rather than its dissolution. ...

11. The effect of carbohydrate and fat variation in euenergetic diets on postabsorptive free fatty acid release

Bisschop, PH; Ackermans, MT; Endert, E; Ruiter, AFC; Meijer, AJ; Kuipers, F; Sauerwein, HP; Romijn, JA

2002-01-01

Diet composition and energy content modulate free fatty acid (FFA) release. The aim of this study was to evaluate the dose-response effects of euenergetic variations in dietary carbohydrate and fat content on postabsorptive FFA release. The rate of appearance (R-a) of palmitate was measured by infus

12. The effect of carbohydrate and fat variation in euenergetic diets on postabsorptive free fatty acid release

Bisschop, PH; Ackermans, MT; Endert, E; Ruiter, AFC; Meijer, AJ; Kuipers, F; Sauerwein, HP; Romijn, JA

Diet composition and energy content modulate free fatty acid (FFA) release. The aim of this study was to evaluate the dose-response effects of euenergetic variations in dietary carbohydrate and fat content on postabsorptive FFA release. The rate of appearance (R-a) of palmitate was measured by

13. Novel slow release nanocomposite nitrogen fertilizers: the impact of polymers on nanocomposite properties and function

Efficient use of fertilizers, especially nitrogen, is essential and strategic to agricultural production. Among the technologies that can contribute to efficient use of fertilizers are slow or controlled release products. This paper describes the impact on structure, urea release rate and function i...

14. Role of hydroxypropylmethylcellulose (HPMC 4000 in the protection of the polymorphs of Piroxicam extended release tablets

A. Merah

2017-02-01

The physico-chemical tests and the dissolution profiles of polymorphs and tablets showed that the metolose incorporated in the tablets at a rate equivalent to 5% could possibly act doubly; initially by protecting the piroxicam polymorphism transition (form II during compression, then modulating its in vitro release (extended release.

15. The effect of carbohydrate and fat variation in euenergetic diets on postabsorptive free fatty acid release

Bisschop, PH; Ackermans, MT; Endert, E; Ruiter, AFC; Meijer, AJ; Kuipers, F; Sauerwein, HP; Romijn, JA

2002-01-01

Diet composition and energy content modulate free fatty acid (FFA) release. The aim of this study was to evaluate the dose-response effects of euenergetic variations in dietary carbohydrate and fat content on postabsorptive FFA release. The rate of appearance (R-a) of palmitate was measured by infus

16. The Effect of Ethanol on the Release of Opioids from Oral Prolonged-Release Preparations

Walden, Malcolm; Nicholls, Fiona A.; Smith, Kevin J.; Tucker, Geoffrey T

2007-01-01

Recent experience has prompted the US FDA to consider whether ethanol ingestion may modify the release characteristics of prolonged-release formulations, where dose dumping may be an issue for patient safety. The influence of ethanol on the in vitro release of opioid drugs from some prolonged-release formulations utilizing different release technologies was examined. Results indicated that the prolonged-release mechanisms remained intact under the testing conditions, although one product show...

17. Imaging renin content and release in the living kidney.

Toma, Ildikó; Kang, Jung Julie; Peti-Peterdi, János

2006-01-01

Renin release is the first, and at least initially, the rate-limiting step in the activation of the renin-angiotensin system, which helps to maintain body salt and water balance. Recent advances in our understanding of pathophysiology have generated a renewed interest in the multiple roles of renin and prorenin as a hormone, enzyme, and signaling molecule. The assays available to measure renin content, release and tissue activity are complex, indirect and work with significant internal errors. We developed an imaging approach to directly visualize renin content and study the dynamics of both the release and tissue activity of renin. Our experimental model uses multiphoton fluorescence microscopy, which is ideal for deep optical sectioning of the living renal tissue. Here we review the application of this renin imaging approach to the dissected, in vitro microperfused glomerulus as well as in the intact kidney in vivo.

18. Herwig 7.0/Herwig++ 3.0 release note

Bellm, Johannes [Karlsruhe Institute of Technology, Institute for Theoretical Physics, Karlsruhe (Germany); Durham University, IPPP, Department of Physics, Durham (United Kingdom); Gieseke, Stefan; Rauch, Michael; Fischer, Nadine; Rauch, Daniel [Karlsruhe Institute of Technology, Institute for Theoretical Physics, Karlsruhe (Germany); Grellscheid, David; Schichtel, Peter; Wilcock, Alexandra [Durham University, IPPP, Department of Physics, Durham (United Kingdom); Plaetzer, Simon [Durham University, IPPP, Department of Physics, Durham (United Kingdom); University of Manchester, Particle Physics Group, School of Physics and Astronomy, Manchester (United Kingdom); Reuschle, Christian [Karlsruhe Institute of Technology, Institute for Theoretical Physics, Karlsruhe (Germany); Florida State University, HEP Theory Group, Department of Physics, Tallahassee (United States); Richardson, Peter [Durham University, IPPP, Department of Physics, Durham (United Kingdom); CERN Theoretical Physics Department, Geneva (Switzerland); Seymour, Michael H.; Nail, Graeme [University of Manchester, Particle Physics Group, School of Physics and Astronomy, Manchester (United Kingdom); Siodmok, Andrzej [CERN Theoretical Physics Department, Geneva (Switzerland); Polish Academy of Sciences, The Henryk Niewodniczanski Institute of Nuclear Physics in Cracow, Cracow (Poland); Harrendorf, Marco A. [Karlsruhe Institute of Technology, Institut fuer Experimentelle Kernphysik, Karlsruhe (Germany); Papaefstathiou, Andreas [CERN Theoretical Physics Department, Geneva (Switzerland)

2016-04-15

A major new release of the Monte Carlo event generator Herwig++ (version 3.0) is now available. This release marks the end of distinguishing Herwig++ and HERWIG development and therefore constitutes the first major release of version 7 of the Herwig event generator family. The new version features a number of significant improvements to the event simulation, including: built-in NLO hard process calculation for virtually all Standard Model processes, with matching to both angular-ordered and dipole shower modules via both subtractive (MC rate at NLO-type) and multiplicative (Powheg-type) algorithms; QED radiation and spin correlations in the angular-ordered shower; a consistent treatment of perturbative uncertainties within the hard process and parton showering. Several of the new features will be covered in detail in accompanying publications, and an update of the manual will follow in due course. (orig.)

19. Release of lysozyme from electrospun PVA/lysozyme-gelatin scaffolds

Dong-zhi YANG; Yu-hua LONG; Jun NIE

2008-01-01

This article describes an electrospinning process in fabricating ultra fine fibers with core-shell structure. A biodegradable polymer, poly(vinyl alcohol) (PVA), was used as the shell; lysozyme was a kind of antioxidant; and gelatin were used as the core. Morphology and microstruc-ture of the ultra fine fibers were characterized by scanning electron microscope (SEM), transmission electron micro-scopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. As a comparison, composite nanofiber PVA/lysozyme-gelatin blend was prepared by a normal electrospinning process. In vitro drug release behaviors of the nanofibrous membranes were determined in phosphate-buffered saline (PBS) solution. It was found that core-shell nanofibers PVA/lysozyme-gelatin obviously exhibit higher initial release rates compared to that of PVA/lysozyme-gelatin blend nanofibers. The current method may find wide application in controlled release of bioactive proteins and tissue engineering.

20. Toxic Release Inventory Chemicals by Groupings

U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) makes available information for more than 600 toxic chemicals that are being used, manufactured, treated, transported, or released...

1. Section 9: Ground Water - Likelihood of Release

HRS training. the ground water pathway likelihood of release factor category reflects the likelihood that there has been, or will be, a release of hazardous substances in any of the aquifers underlying the site.

2. Rapid Retinal Release from a Cone Visual Pigment Following Photoactivation*

Chen, Min-Hsuan; Kuemmel, Colleen; Birge, Robert R.; Knox, Barry E.

2012-01-01

As part of the visual cycle, the retinal chromophore in both rod and cone visual pigments undergoes reversible Schiff base hydrolysis and dissociation following photobleaching. We characterized light-activated retinal release from a short-wavelength sensitive cone pigment (VCOP) in 0.1% dodecyl maltoside using fluorescence spectroscopy. The half-time (t1/2) of retinal release from VCOP was 7.1 s, 250-fold faster than rhodopsin. VCOP exhibited pH-dependent release kinetics, with the t1/2 decreasing from 23 s to 4 s with pH 4.1 to 8, respectively. However, the Arrhenius activation energy (Ea) for VCOP derived from kinetic measurements between 4° and 20°C was 17.4 kcal/mol, similar to 18.5 kcal/mol for rhodopsin. There was a small kinetic isotope (D2O) effect in VCOP, but less than that observed in rhodopsin. Mutation of the primary Schiff base counterion (VCOPD108A) produced a pigment with an unprotonated chromophore (⌊max = 360 nm) and dramatically slowed (t1/2 ~ 6.8 min) light-dependent retinal release. Using homology modeling, a VCOP mutant with two substitutions (S85D/ D108A) was designed to move the counterion one alpha helical turn into the transmembrane region from the native position. This double mutant had a UV-visible absorption spectrum consistent with a protonated Schiff base (⌊max = 420 nm). Moreover, VCOPS85D/D108A mutant had retinal release kinetics (t1/2 = 7 s) and Ea (18 kcal/mol) similar to the native pigment exhibiting no pH-dependence. By contrast, the single mutant VCOPS85D had a ~3-fold decrease in retinal release rate compared to the native pigment. Photoactivated VCOPD108A had kinetics comparable to a rhodopsin counterion mutant, RhoE113Q, both requiring hydroxylamine to fully release retinal. These results demonstrate that the primary counterion of cone visual pigments is necessary for efficient Schiff base hydrolysis. We discuss how the large differences in retinal release rates between rod and cone visual pigments arise, not from

3. Mars Express releases Beagle 2

2003-12-01

At 9:31 CET, the crucial sequence started to separate the Beagle 2 lander from Mars Express. As data from Mars Express confirm, the pyrotechnic device was fired to slowly release a loaded spring, which gently pushed Beagle 2 away from the mother spacecraft. An image from the onboard visual monitoring camera (VMC) showing the lander drifting away is expected to be available later today. Since the Beagle 2 lander has no propulsion system of its own, it had to be put on the correct course for its descent before it was released. For this reason, on 16 December the trajectory of the whole Mars Express spacecraft had to be adjusted to ensure that Beagle 2 would be on course to enter the atmosphere of Mars. This manoeuvre, called "retargeting'' was critical: if the entry angle is too steep, the lander could overheat and burn up in the atmosphere; if the angle is too shallow, the lander might skim like a pebble on the surface of a lake and miss its target. This fine targeting and today's release were crucial manoeuvres for which ESA's Ground Control Team at ESOC (European Space Operations Centre) had trained over the past several months. The next major milestone for Mars Express will be the manoeuvre to enter into orbit around Mars. This will happen at 3:52 CET on Christmas morning, when Beagle 2 is expected to land on the surface of Mars. "Good teamwork by everybody - ESA, industry and the Beagle 2 team - has got one more critical step accomplished. Mars, here comes Europe!" said David Southwood, ESA Director of Science.

4. Comparing post-release survival andhabitat use bycaptive-bred Cabot’s Tragopan (Tragopan caboti) inan experimental test ofsoft-release reintroduction strategies

Boye Liu; Li Li; Huw Lloyd; Canwei Xia; Yanyun Zhang; Guangmei Zheng

2016-01-01

Background: Restoring a viable population by reintroduction is the ultimate goal of a large number of ex situ con-servation projects for endangered animals. However, many reintroductions fail to establish a population in the wild, partly because released animals cannot acclimate to the native environment of the release site, resulting in very low survival rates. Acclimation training is a technique to resolve this problem, although it does not have positive results in all species. We tested whether acclimation training and soft-release could improve the reintroduction success for captive-bred Cabot’s Tragopan (Tragopan caboti), an endangered pheasant in southern China. Methods: Reintroduction of captive-bred Cabot’s Tragopan was carried out in the Taoyuandong National Nature Reserve, China from 2010 to 2011. We built a soft-release enclosure for acclimation training in the typical montane habitat of this pheasant. Nine birds were acclimated to the environment of this release site in this cage for more than 50 days before release (“trained birds”), while 11 birds remained only in the cage for 3 days prior to release (“untrained birds”). Released birds were tagged with a collar radio-transmitter. Results: Post-release monitoring revealed that the survival rate of trained birds was higher than that of untrained birds after 50 days (trained: 85.7%; untrained: 20.0%). Cox regression analysis showed that there was a signiifcant difference in the mortality rates between the trained and untrained birds. In addition, a survey of the habitat of the experimental and the control groups showed signiifcant differences in habitat selection between the groups. Conclusion: Our study suggests that pre-release acclimatization training is an important factor that can lead to improved survival and habitat selection of captive-bred reintroduced tragopans.

5. DVD With High Gapacity Released

2002-01-01

After two years of research and development, the Center for International Cultural Exchange under the Ministry of Culture of China has recently released a new type of DVD which is double-faced, double-system and bears ten languages. Teststatistics show that all its indicators come up withthose of its foreign counterparts. Now it has beenput into mass production.This new type of DVD features the following performances. It is a high-clarity one, with the horizontal clarity more than 500. It has a superb sound effect, capable of recording various stereo signals such as DOLBY DIGITAL and DTS. It can record dubbing in eight languages and subtitles

6. Evaluation of Sterculia foetida gum as controlled release excipient.

Chivate, Amit Ashok; Poddar, Sushilkumar Sharatchandra; Abdul, Shajahan; Savant, Gaurav

2008-01-01

The purpose of the research was to evaluate Sterculia foetida gum as a hydrophilic matrix polymer for controlled release preparation. For evaluation as a matrix polymer; characterization of Sterculia foetida gum was done. Viscosity, pH, scanning electronmicrographs were determined. Different formulation aspects considered were: gum concentration (10-40%), particle size (75-420 microm) and type of fillers and those for dissolution studies; pH, and stirring speed were considered. Tablets prepared with Sterculia foetida gum were compared with tablets prepared with Hydroxymethylcellulose K15M. The release rate profiles were evaluated through different kinetic equations: zero-order, first-order, Higuchi, Hixon-Crowell and Korsemeyer and Peppas models. The scanning electronmicrographs showed that the gum particles were somewhat triangular. The viscosity of 1% solution was found to be 950 centipoise and pH was in range of 4-5. Suitable matrix release profile could be obtained at 40% gum concentration. Higher sustained release profiles were obtained for Sterculia foetida gum particles in size range of 76-125 microm. Notable influences were obtained for type of fillers. Significant differences were also observed with rotational speed and dissolution media pH. The in vitro release profiles indicated that tablets prepared from Sterculia foetida gum had higher retarding capacity than tablets prepared with Hydroxymethylcellulose K15M prepared tablets. The differential scanning calorimetry results indicated that there are no interactions of Sterculia foetida gum with diltiazem hydrochloride. It was observed that release of the drug followed through surface erosion and anomalous diffusion. Thus, it could be concluded that Sterculia foetida gum could be used a controlled release matrix polymer.

7. Radionuclide Release after Channel Flow Blockage Accident in CANDU-6 Plant

Choi, Hoon; Jun, Hwang Yong [Korea Electric Power Corporation Research Institute, Daejeon (Korea, Republic of)

2011-05-15

The channel flow blockage accident is one of the in core loss of coolant accidents, the release path of radionuclide is very different from conventional loss of coolant accidents. The large amount of radionuclide released from broken channel is being washed during it passes through the moderator in Calandria. The objective of containment behavior analysis for channel flow blockage event is to assess the amount of radionuclide release to the ambient atmosphere. Radionuclide release rates in case of channel flow blockage with all safety system available, that is containment building is intact, as well as with containment system impairment are analyzed with GOTHIC and SMART code

8. Real-time UV imaging of nicotin release from transdermal patch

Østergaard, Jesper; Meng-Lund, Emil; Larsen, Susan Weng

2010-01-01

PURPOSE: This study was conducted to characterize UV imaging as a platform for performing in vitro release studies using Nicorette® nicotine patches as a model drug delivery system. METHODS: The rate of nicotine release from 2 mm diameter patch samples (Nicorette®) into 0.067 M phosphate buffer, p...... of nicotine. Release profiles obtained from UV imaging were in qualitative agreement with results from the paddle-over-disk release method. CONCLUSION: Visualization as well as quantification of nicotine concentration gradients was achieved by UV imaging in real time. UV imaging has the potential to become...

9. The blend modification of EVA-150/starch and controlled-release of imazethapyr

TAI Li-min; ZHU Xiu-yun

2008-01-01

The EVA-150 and starch were extruded by extruding press and the bio-degra-dation composite material was prepared to use as the controlled-release matrix of imazethapyr. The compatibility and crystallinity of EVA-150/starch blending were analyzed by SEM and DSC, and the controlled-released performance of imazethapyr in the carriers was also investigated by UV analysis. The results show that EVA-150/starch composite matrix has the obvious controlled-released function and the release rates of imazethapyr all exceed 50% in the environment of pH4, pH7, or pH9 after nine days.

10. The blend modification of EVA-150/starch and controlled-release of imazethapyr

TAI LI-min; ZHU Xiu-yun

2008-01-01

The EVA-150 and starch were extruded by extruding press and the bio-degradation composite material was prepared to use as the controlled-release matrix of imazethapyr.The compatibility and crystallinity of EVA-150/starch blending were analyzed by SEM and DSC,and the controlled-released performance of imazethapyr in the carriers was also investigated by UV analysis.The results show that EVA-150/starch composite matrix has the obvious controlled-released function and the release rates of imazethapyr all exceed 50% in the environment of pH4,pH7,or pH9 after nine days.

11. Release kinetics of drugs from rosin-glycerol ester microcapsules prepared by solvent evaporation technique.

Sheorey, D S; Dorle, A K

1991-01-01

Rosin-glycerol ester microcapsules containing sulphadiazine were prepared by solvent evaporation technique. The goodness of fit of the release data was tested with first order, Higuchi matrix model and Hixon-Crowell cube root law. All these models were sufficiently linear. Application of the differential rate treatment showed that release from most of the microcapsules followed first order equation. Whereas up to 40-50 per cent of release, a zero order, membrane controlled kinetics was observed, the release is apparently first order under nonsteady, state conditions.

12. Investigation into the Effect of Ethylcellulose Viscosity Variation on the Drug Release of Metoprolol Tartrate and Acetaminophen Extended Release Multiparticulates-Part I.

Mehta, R; Teckoe, J; Schoener, C; Workentine, S; Ferrizzi, D; Rajabi-Siahboomi, A

2016-12-01

Ethylcellulose is one of the most commonly used polymers to develop reservoir type extended release multiparticulate dosage forms. For multiparticulate extended release dosage forms, the drug release is typically governed by the properties of the barrier membrane coating. The ICH Pharmaceutical Development Guideline (ICH Q8) requires an understanding of the influence of critical material attributes and critical process parameters on the drug release of a pharmaceutical product. Using this understanding, it is possible to develop robust formulations with consistent drug release characteristics. Critical material attributes for ethylcellulose were evaluated, and polymer molecular weight variation (viscosity) was considered to be the most critical attribute that can impact drug release. To investigate the effect of viscosity variation within the manufacturer's specifications of ethylcellulose, extended release multiparticulate formulations of two model drugs, metoprolol tartrate and acetaminophen, were developed using ETHOCEL™ as the rate controlling polymer. Quality by Design (QbD) samples of ETHOCEL Std. 10, 20, and 100 Premium grades representing the low, medium, and high molecular weight (viscosity) material were organically coated onto drug layered multiparticulates to a 15% weight gain (WG). The drug release was found to be similar (f 2 > 50) for both metoprolol tartrate and acetaminophen multiparticulates at different coating weight gains of ethylcellulose, highlighting consistent and robust drug release performance. The use of ETHOCEL QbD samples also serves as a means to develop multiparticulate dosage formulations according to regulatory guidelines.

13. Individualized optimal release angles in discus throwing.

Leigh, Steve; Liu, Hui; Hubbard, Mont; Yu, Bing

2010-02-10

The purpose of this study was to determine individualized optimal release angles for elite discus throwers. Three-dimensional coordinate data were obtained for at least 10 competitive trials for each subject. Regression relationships between release speed and release angle, and between aerodynamic distance and release angle were determined for each subject. These relationships were linear with subject-specific characteristics. The subject-specific relationships between release speed and release angle may be due to subjects' technical and physical characteristics. The subject-specific relationships between aerodynamic distance and release angle may be due to interactions between the release angle, the angle of attack, and the aerodynamic distance. Optimal release angles were estimated for each subject using the regression relationships and equations of projectile motion. The estimated optimal release angle was different for different subjects, and ranged from 35 degrees to 44 degrees . The results of this study demonstrate that the optimal release angle for discus throwing is thrower-specific. The release angles used by elite discus throwers in competition are not necessarily optimal for all discus throwers, or even themselves. The results of this study provide significant information for understanding the biomechanics of discus throwing techniques.

14. 28 CFR 2.33 - Release plans.

2010-07-01

... Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.33 Release plans. (a) A grant of parole is conditioned upon the approval of release plans by the Regional Commissioner. In general...

15. Prisoners' Perspectives on Strategies for Release.

1996-01-01

Examines questions regarding the perceptions of New York State prisoners (N=263), their chances of an early release, and their strategies to expedite the release process. Findings suggest that inmates view all activities thought to expedite release as important. Many prisoners wished to eliminate the "game playing" thought associated…

16. Data release of the LAMOST pilot survey

A-Li Luo; Jian-Nan Zhang; Shi-Hai Yang; Zheng-Qiu Yao; Yong Yu; Hui Yuan; Chao Zhai; En-Peng Zhang; Jing Zhang; Li-Ping Zhang; Wei Zhang; Yong Zhang; Zhong-Rui Bai; Zhen-Chao Zhang; Ming Zhao; Fang Zhou; Yong-Tian Zhu; Jie Zhu; Si-Cheng Zou; Xiao-Yan Chen; Feng-Fei Wang; Yan-Xin Guo; Jian-Jun Chen; Bing Du; Xiao Kong; Ya-Juan Lei; Yin-Bi Li; Hao-Tong Zhang; Yi-Han Song; Yue Wu; Yan-Xia Zhang; Xin-Lin Zhou; Fang Zuo; Peng Du; Lin He; Wen Hou; Yi-Qiao Dong; Jian Li; Yong-Heng Zhao; Guang-Wei Li; Shuang Li; Jing Song; Yuan Tian; Meng-Xin Wang; Ke-Fei Wu; Hui-Qin Yang; Hai-Long Yuan; Shu-Yun Cao; Hai-Yuan Chen; Gang Zhao; Kun-Xin Chen; Ying Chen; Jia-Ru Chu; Lei Feng; Xue-Fei Gong; Bo-Zhong Gu; Yong-Hui Hou; Zhi-Ying Huo; Hong-Zhuan Hu; Ning-Sheng Hu; Xiang-Qun Cui; Zhong-Wen Hu; Lei Jia; Fang-Hua Jiang; Xiang Jiang; Zi-Bo Jiang; Ge Jin; Ai-Hua Li; Qi Li; Xin-Nan Li; Yan Li; Guo-Ping Li; Ye-Ping Li; Gen-Rong Liu; Guan-Qun Liu; Zhi-Gang Liu; Qi-Shuai Lu; Wen-Zhi Lu; Yu Luo; Yin-Dun Mao; Li Men; Ji-Jun Ni; Yao-Quan Chu; Yong-Jun Qi; Zhao-Xiang Qi; Huo-Ming Shi; Ding-Qiang Su; Shi-Wei Sun; Hong-Jun Su; Zheng-Hong Tang; Qing-Sheng Tao; Liang-Ping Tu; Da-Qing Wang; Jian-Rong Shi; Dan Wang; Guo-Min Wang; Hai Wang; Jia-Ning Wang; Jian Wang; Jian-Ling Wang; Jian-Ping Wang; Lei Wang; Shou-Guan Wang; Shu-Qing Wang; Gang Wang; Ya-Nan Wang; You Wang; Yue-Fei Wang; Ming-Zhi Wei; Xiang-Xiang Xue; Xiao-Zheng Xing; Ling-Zhe Xu; Xin-Qi Xu; Yan Xu; De-Hua Yang

2012-01-01

This paper describes the data release of the LAMOST pilot survey,which includes data reduction,calibration,spectral analysis,data products and data access.The accuracy of the released data and the information about the FITS headers of spectra are also introduced.The released data set includes 319 000 spectra and a catalog of these objects.

17. Combined statistical analysis of landslide release and propagation

Mergili, Martin; Rohmaneo, Mohammad; Chu, Hone-Jay

2016-04-01

quantify this relationship by a set of empirical curves. (6) Finally, we multiply the zonal release probability with the impact probability in order to estimate the combined impact probability for each pixel. We demonstrate the model with a 167 km² study area in Taiwan, using an inventory of landslides triggered by the typhoon Morakot. Analyzing the model results leads us to a set of key conclusions: (i) The average composite impact probability over the entire study area corresponds well to the density of observed landside pixels. Therefore we conclude that the method is valid in general, even though the concept of the zonal release probability bears some conceptual issues that have to be kept in mind. (ii) The parameters used as predictors cannot fully explain the observed distribution of landslides. The size of the release zone influences the composite impact probability to a larger degree than the pixel-based release probability. (iii) The prediction rate increases considerably when excluding the largest, deep-seated, landslides from the analysis. We conclude that such landslides are mainly related to geological features hardly reflected in the predictor layers used.

18. Molecularly Imprinted Polymers for 5-Fluorouracil Release in Biological Fluids

Franco Alhaique

2007-04-01

Full Text Available The aim of this work was to investigate the possibility of employing Molecularly Imprinted Polymers (MIPs as a controlled release device for 5-fluorouracil (5-FU in biological fluids, especially gastrointestinal ones, compared to Non Imprinted Polymers (NIPs. MIPs were synthesized using methacrylic acid (MAA as functional monomer and ethylene glycol dimethacrylate (EGDMA as crosslinking agent. The capacity of the polymer to recognize and to bind the template selectively in both organic and aqueous media was evaluated. An in vitro release study was performed both in gastrointestinal and in plasma simulating fluids. The imprinted polymers bound much more 5-Fu than the corresponding non-imprinted ones and showed a controlled/sustained drug release, with MIPs release rate being indeed much more sustained than that obtained from NIPs. These polymers represent a potential valid system for drug delivery and this study indicates that the selective binding characteristic of molecularly imprinted polymers is promising for the preparation of novel controlled release drug dosage form.

19. Molecularly imprinted polymers for 5-fluorouracil release in biological fluids.

Puoci, Francesco; Iemma, Francesca; Cirillo, Giuseppe; Picci, Nevio; Matricardi, Pietro; Alhaiqu, Franco

2007-04-18

The aim of this work was to investigate the possibility of employing Molecularly Imprinted Polymers (MIPs) as a controlled release device for 5-fluorouracil (5-FU) in biological fluids, especially gastrointestinal ones, compared to Non Imprinted Polymers (NIPs). MIPs were synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as crosslinking agent. The capacity of the polymer to recognize and to bind the template selectively in both organic and aqueous media was evaluated. An in vitro release study was performed both in gastrointestinal and in plasma simulating fluids. The imprinted polymers bound much more 5-Fu than the corresponding non-imprinted ones and showed a controlled/sustained drug release, with MIPs release rate being indeed much more sustained than that obtained from NIPs. These polymers represent a potential valid system for drug delivery and this study indicates that the selective binding characteristic of molecularly imprinted polymers is promising for the preparation of novel controlled release drug dosage form.

20. Drug release from porous silicon for stable neural interface

Sun, Tao, E-mail: taosun@hotmail.com.hk [Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Tsang, Wei Mong [Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Park, Woo-Tae [Institute of Microelectronics, Agency for Science, Technology and Research (A-STAR) (Singapore); Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul (Korea, Republic of)

2014-02-15

70 μm-thick porous Si (PSi) layer with the pore size of 11.1 ± 7.6 nm was formed on an 8-in. Si wafer via an anodization process for the microfabrication of a microelectrode to record neural signals. To reduce host tissue responses to the microelectrode and achieve a stable neural interface, water-soluble dexamethesone (Dex) was loaded into the PSi via incubation with the drug solution overnight. After the drug loading process, the pore size of PSi reduced to 4.7 ± 2.6 nm on the basis of scanning electron microscopic (SEM) images, while its wettability was remarkably enhanced. Fluorescence images demonstrated that Dex was loaded into the porous structure of the PSi. Degradation rate of the PSi was investigated by incubation in distilled water for 21 days. Moreover, the drug release profile of the Dex-loaded PSi was a combination of an initial burst release and subsequent sustained release. To evaluate cellular responses to the drug release from the PSi, primary astrocytes were seeded on the surface of samples. After 2 days of culture, the Dex-loaded PSi could not only moderately prevent astrocyte adhesion in comparison with Si, but also more effectively suppress the activation of primary astrocytes than unloaded PSi due to the drug release. Therefore, it might be an effective method to reduce host tissue responses and stabilize the quality of the recorded neural signal by means of loading drugs into the PSi component of the microelectrode.

1. Nutrient Release from Disturbance of Infiltration System Soils during Construction

Daniel P. Treese

2012-01-01

Full Text Available Subsurface infiltration and surface bioretention systems composed of engineered and/or native soils are preferred tools for stormwater management. However, the disturbance of native soils, especially during the process of adding amendments to improve infiltration rates and pollutant removal, may result in releases of nutrients in the early life of these systems. This project investigated the nutrient release from two soils, one disturbed and one undisturbed. The disturbed soil was collected intact, but had to be air-dried, and the columns repacked when soil shrinkage caused bypassing of water along the walls of the column. The undisturbed soil was collected and used intact, with no repacking. The disturbed soil showed elevated releases of nitrogen and phosphorus compared to the undisturbed soil for approximately 0.4 and 0.8 m of runoff loading, respectively. For the undisturbed soil, the nitrogen release was delayed, indicating that the soil disturbance accelerated the release of nitrogen into a very short time period. Leaving the soil undisturbed resulted in lower but still elevated effluent nitrogen concentrations over a longer period of time. For phosphorus, these results confirm prior research which demonstrated that the soil, if shown to be phosphorus-deficient during fertility testing, can remove phosphorus from runoff even when disturbed.

2. Approaches to evaluating weathering effects on release of ...

Increased production and use of engineered nanomaterials (ENMs) over the past decade has increased the potential for the transport and release of these materials into the environment. Here we present results of two separate studies designed to simulate the effects of weathering on the potential release of multiwalled carbon nanotubes (MWCNTs) from polyamide or epoxy composites, and nanosilica from composites with low-density polyethylene (LOPE) with added pro-oxidant. With these weathering-resistant ENMs, the release was primarily driven by degradation of the polymer matrix. The MWCNT-polymer composites were investigated in a pilot inter-laboratory study to simulate the effects of weathering on the potential release of multiwalled carbon nanotubes (MWCNTs) from their composites with two polymers. Wafers of MWCNTs in epoxy and polyamide nanocomposi tes were exposed in four laboratories in the US and Europe under carefully controlled conditions to cycles of simulated sunlight and rainfall over a 2000-hour period. Particles released upon submersion of the weathered wafers in the leaching fluid described in EPA Method 1311 were analyzed by Transmission Electron Microscopy (TEM), Inductively Coupled Plasma- Mass Spectrometry (ICP-MS), and Ultraviolet-Visible Spectroscopy (UV-Vis). Rates ofrelease of MWCNTS determined by ICP-MS (Co associatedwith MWCNTS) and UY-Vis agreed within a factor of two. Other weathering studies of nanosilica-LDPE composites were conducted usi

3. Factors controlling alkali salt deposition in recovery boilers. Release mechanisms

McKeough, P.; Kurkela, M.; Kylloenen, H.; Tapola, E. [VTT Energy, Espoo (Finland). Process Technology Group

1997-10-01

The research was part of an ongoing cooperative research effort aimed at developing a model to describe the behaviour of inorganic compounds in kraft recovery boilers. During 1996 experimental investigations of sulphur release were continued. Experiments at elevated pressures and employing larger particle sizes were performed in order to gain information about mass transfer effects. The first experiments yielding data on the rates of the sulphur-release reactions were performed. This data will be used as the basis of a drop model for sulphur release being developed in cooperation with another research group. The other part of the work during 1996 explored the possibility of using chemical equilibrium calculations to predict the release of sodium, potassium and chlorine in the recovery furnace. The approach is essentially different from that employed in earlier studies in that the effects of fume formation are taken into account. So far, the predictions of the chemical equilibrium release model have, in no way, conflicted with field measurements. (orig.)

4. Studies of Moisture Absorption and Release Behaviour of Akund Fiber

Xue Yang

2012-01-01

Full Text Available Akund fiber is a new type of natural cellulose fiber. Because of its excellent properties, akund fiber has become one of the new ecological materials which have huge development potential. Recently natural fibers have shown great promise in a variety of applications that were previously dominated by synthetic fibers due to their important aspects of biocompatibility, possible biodegradation, nontoxicity, and abundance. Moisture absorption and release behaviour of natural fiber plastic composites is one major concern in their outdoor applications. So the knowledge of the moisture content and the moisture absorption and release rate is very much essential for the application of akund fiber as an excellent reinforcement in polymers. An effort has been made to study the moisture absorption and release behaviour of akund fiber and the mechanical performance of it at relative air humidity from 0% to 100%. The gain and loss in moisture content in akund fiber due to water absorption and release were measured as a function of exposure time under the environment, in which temperature is 20°C and humidity is 65%. The regression equations of the absorption and release process were established.

5. Controlled release of ethylene via polymeric films for food packaging

Pisano, Roberto; Bazzano, Marco; Capozzi, Luigi Carlo; Ferri, Ada; Sangermano, Marco

2015-12-01

In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

6. A descriptive study of 972 consecutive cases of carpal tunnel release: role of ancillary procedures

Berkan Mersa

2013-04-01

Conclusion: Additional procedures is advocated as adjuncts to the carpal ligament release, in an effort to decrease the failure rate after operation in indicated cases. [Hand Microsurg 2013; 2(1.000: 18-22

7. Preparation, Characterization and in vivo Evaluation of Simple Monolithic Ethylcellulose-coated Pellets Containing Topiramate with Biphasic Release Characteristics.

Gong, Wei; Wang, Yuli; Shao, Shuai; Xie, Si; Shan, Li; Yang, Meiyan; Gao, Chunsheng; Zhong, Wu

2016-01-01

In our previous study, polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former to prepare ethylcellulose (EC)-coated pellets to deliver topiramate (TPM) for a controlled release profile. The objective of this work was to further optimize the formulation and evaluate the in vivo profiles of TPM sustained-release pellets. Similar to the previous formulation with no binder, the in vitro drug release of TPM sustained-release pellets with 50% PVP binder in drug layer was sensitive to pore-former PVP level ranged from 27.0% to 29.0%. The higher the level of PVP was, the quicker release rate in vitro was. Moreover, when the proportion of poreformer PVP decreased, the Cmax decreased, and the tmax and mean residence time of TPM coated pellets were both prolonged. The in vitro release profile of optimal formulation showed biphasic release characteristics similar to reference formulation Trokendi XR(®), i.e., involving immediate release of TPM in initial release stage followed by a sustained release up to 24 h. Moreover, the impact of the pH of release medium on the drug release rate of TPM sustained-release pellets was not significant. The release mechanism of TPM from the sustained-release pellets might be the interaction of diffusion (coating-film) and corrosion (drug layer). The in vivo pharmacokinetics results showed the TPM sustained-release pellets had the similar in vivo pattern compared with Trokendi XR(®). These studies provide valuable basis for further development of TPM sustained-release pellets.

8. Nuclear energy release from fragmentation

Li, Cheng [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Souza, S.R. [Instituto de Física, Universidade Federal do Rio de Janeiro Cidade Universitária, Caixa Postal 68528, 21945-970 Rio de Janeiro (Brazil); Tsang, M.B. [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); National Superconducting Cyclotron Laboratory and Physics and Astronomy Department, Michigan State University, East Lansing, MI 48824 (United States); Zhang, Feng-Shou, E-mail: fszhang@bnu.edu.cn [The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000 (China)

2016-08-15

It is well known that binary fission occurs with positive energy gain. In this article we examine the energetics of splitting uranium and thorium isotopes into various numbers of fragments (from two to eight) with nearly equal size. We find that the energy released by splitting {sup 230,232}Th and {sup 235,238}U into three equal size fragments is largest. The statistical multifragmentation model (SMM) is applied to calculate the probability of different breakup channels for excited nuclei. By weighing the probability distributions of fragment multiplicity at different excitation energies, we find the peaks of energy release for {sup 230,232}Th and {sup 235,238}U are around 0.7–0.75 MeV/u at excitation energy between 1.2 and 2 MeV/u in the primary breakup process. Taking into account the secondary de-excitation processes of primary fragments with the GEMINI code, these energy peaks fall to about 0.45 MeV/u.

9. Nuclear energy release from fragmentation

Li, Cheng; Souza, S. R.; Tsang, M. B.; Zhang, Feng-Shou

2016-08-01

It is well known that binary fission occurs with positive energy gain. In this article we examine the energetics of splitting uranium and thorium isotopes into various numbers of fragments (from two to eight) with nearly equal size. We find that the energy released by splitting 230,232Th and 235,238U into three equal size fragments is largest. The statistical multifragmentation model (SMM) is applied to calculate the probability of different breakup channels for excited nuclei. By weighing the probability distributions of fragment multiplicity at different excitation energies, we find the peaks of energy release for 230,232Th and 235,238U are around 0.7-0.75 MeV/u at excitation energy between 1.2 and 2 MeV/u in the primary breakup process. Taking into account the secondary de-excitation processes of primary fragments with the GEMINI code, these energy peaks fall to about 0.45 MeV/u.

10. Nanoparticle release from dental composites.

Van Landuyt, K L; Hellack, B; Van Meerbeek, B; Peumans, M; Hoet, P; Wiemann, M; Kuhlbusch, T A J; Asbach, C

2014-01-01

Dental composites typically contain high amounts (up to 60 vol.%) of nanosized filler particles. There is a current concern that dental personnel (and patients) may inhale nanosized dust particles (composite dust was analyzed in real work conditions. Exposure measurements of dust in a dental clinic revealed high peak concentrations of nanoparticles in the breathing zone of both dentist and patient, especially during aesthetic treatments or treatments of worn teeth with composite build-ups. Further laboratory assessment confirmed that all tested composites released very high concentrations of airborne particles in the nanorange (>10(6)cm(-3)). The median diameter of airborne composite dust varied between 38 and 70 nm. Electron microscopic and energy dispersive X-ray analysis confirmed that the airborne particles originated from the composite, and revealed that the dust particles consisted of filler particles or resin or both. Though composite dust exhibited no significant oxidative reactivity, more toxicological research is needed. To conclude, on manipulation with the bur, dental composites release high concentrations of nanoparticles that may enter deeply into the lungs. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

11. Interaction between fed and gastric media (ensure Plus) and different hypromellose based caffeine controlled release tablets; comparison and mechanistic study of caffeine release in fed and fasted media versus water using USP dissolution apparatus 3

Franek, Frans; Holm, Per; Larsen, Frank

2014-01-01

The aim of the study was to investigate caffeine release in fed and fasted state media from three controlled release matrix tablets containing different HPMC viscosity grades. The biorelevant in vitro dissolution methods utilize the USP 3 dissolution apparatus and biorelevant media to simulate fed...... and fasted gastro-intestinal dissolution conditions. The effect of tablet reciprocation rate (dip speed) in dissolution media (10 and 15 dips per minute) and media (water, fed and fasted) on caffeine release rate from – and erosion rate of – 100, 4000 and 15,000 mPa s HPMC viscosity tablets was investigated....... Using fasted media instead of water slightly decreases caffeine release from 100 and 4000 mPa s HPMC viscosity tablets as well as erosion rates, while 15,000 mPa s tablets remain unaffected. Fed compared to fasted media decreases caffeine release rate, and the food effect is greater for the 100 mPa s...

12. Comparing Moment Release and Tremor Amplitudes in Cascadia ETS Events

Hall, K.; Schmidt, D. A.; Houston, H.

2016-12-01

A proposed relationship between the moment release of ETS and tremor duration. [Aguiar et al., 2009] compared moment from static inversions of slip with the overall duration of the entire ETS, finding a linear relationship between moment release and tremor duration. There is a logical relationship between the processes that generate slip and those that generate tremor. Spatially, we have seen that slip may occur up-dip of tremor [Houston, 2012] and [Hall and Houston, 2014] in Northern Cascadia. On the other hand, Bartlow et al. [2011] did not resolve a spatio-temporal difference between tremor and slow slip for the 2009 ETS in mid-Cascadia. This raises the possibility that there could be an as-yet-unrecognized regional difference. In order to explore spatio-temporal relationships between tremor and slow slip, I used the Extended Network Inversion Filter (ENIF) [Segall and Matthews, 1997] together with PNSN tremor locations. Preliminary results for the 2010 ETS event yield a M6.8 event that begins near Seattle on August 8th and propagates mainly to the north with some smaller slip to the south, following the propagation of the tremor, a pattern consistent with our static inversion results. The slip-pulse nature of the ETS process is clearly imaged, with some fault patches continuing to slip for several days after tremor has passed through, but not for the entire duration of the event. I then looked at tremor amplitudes [Ulberg and Creager, AGU Abs, 2013], which represent the amount of energy released in a five-minute tremor window. Because the tremor catalog has much finer temporal resolution than the GPS data, I sum the daily tremor amplitudes and compare to daily moment-rates from the time-dependent inversion, obtaining a correlation between moment-rate and tremor amplitude rate. This suggests that the energy released by tremor may be a direct proxy for energy released by slip.

13. Cortisol release in response to UVB exposure in Xiphophorus fish.

Contreras, Adam J; Boswell, Mikki; Downs, Kevin P; Pasquali, Amanda; Walter, Ronald B

2014-06-01

Xiphophorus fishes are comprised of 26 known species. Interspecies hybridization between select species has been utilized to produce experimental models to study melanoma development. Xiphophorus melanoma induction protocols utilize ultraviolet light (UVB) to induce DNA damage and associated downstream tumorigenesis. However, the impact of induced stress caused by the UVB treatment of the experimental animals undergoing tumor induction protocols has not been assessed. Stress is an adaptive physiological response to excessive or unpredictable environmental stimuli. The stress response in fishes may be measured by an assay of cortisol released into the water. Here, we present results from investigations of stress response during an experimental treatment and UVB exposure in Xiphophorus maculatus Jp 163 B, Xiphophorus couchianus, and F1 interspecies hybrids produced from the mating X. maculatus Jp 163 B×X. couchianus. Overall, cortisol release rates for males and females after UVB exposure showed no statistical differences. At lower UVB doses (8 and 16kJ/m(2)), X. couchianus exhibited 2 fold higher levels of DNA damage then either X. maculatus or the F1 hybrid. However, based on the cortisol release rates, none of the fish types tested induced a primary stress response at the UVB lower doses (8 and 16kJ/m(2)). In contrast, at a very high UVB dose (32kJ/m(2)) both X. maculatus and the F1 hybrid showed a 5 fold increase in the cortisol release rate. To determine the effect of pigmentation on UVB induced stress, wild type and albino Xiphophorus hellerii were exposed to UVB (32kJ/m(2)). Albino X. hellerii exhibited 3.7 fold increase in the cortisol release while wild type X. hellerii did not exhibit a significant cortisol response to UVB. Overall, the data suggest the rather low UVB doses often employed in tumor induction protocols do not induce a primary stress response in Xiphophorus fishes.

14. Controls on Fe(II)-Activated Trace Element Release from Goethite and Hematite

Frierdich, Andrew J.; Catalano, Jeffrey G. (WU)

2012-03-26

Electron transfer and atom exchange (ETAE) between aqueous Fe(II) and Fe(III) oxides induces surface growth and dissolution that affects trace element fate and transport. We have recently demonstrated Ni(II) cycling through goethite and hematite (adsorbed Ni incorporates into the mineral structure and preincorporated Ni releases to solution) during Fe(II)-Fe(III) ETAE. However, the chemical parameters affecting net trace element release remain unknown. Here, we examine the chemical controls on Ni(II) and Zn(II) release from Ni- and Zn-substituted goethite and hematite during reaction with Fe(II). Release follows a rate law consistent with surface reaction limited mineral dissolution and suggests that release occurs near sites of Fe(III) reductive dissolution during Fe(II)-Fe(III) ETAE. Metal substituent type affects reactivity; Zn release is more pronounced from hematite than goethite, whereas the opposite trend occurs for Ni. Buildup of Ni or Zn in solution inhibits further release but this resumes upon fluid exchange, suggesting that sustained release is possible under flow conditions. Mineral and aqueous Fe(II) concentrations as well as pH strongly affect sorbed Fe(II) concentrations, which directly control the reaction rates and final metal concentrations. Our results demonstrate that structurally incorporated trace elements are mobilized from iron oxides into fluids without abiotic or microbial net iron reduction. Such release may affect micronutrient availability, contaminant transport, and the distribution of redox-inactive trace elements in natural and engineered systems.

15. Halloysite clay nanotubes for controlled release of protective agents.

Lvov, Yuri M; Shchukin, Dmitry G; Möhwald, Helmuth; Price, Ronald R

2008-05-01

Halloysite aluminosilicate nanotubes with a 15 nm lumen, 50 nm external diameter, and length of 800 +/- 300 nm have been developed as an entrapment system for loading, storage, and controlled release of anticorrosion agents and biocides. Fundamental research to enable the control of release rates from hours to months is being undertaken. By variation of internal fluidic properties, the formation of nanoshells over the nanotubes and by creation of smart caps at the tube ends it is possible to develop further means of controlling the rate of release. Anticorrosive halloysite coatings are in development and a self-healing approach has been developed for repair mechanisms through response activation to external impacts. In this Perspective, applications of halloysite as nanometer-scale containers are discussed, including the use of halloysite tubes as drug releasing agents, as biomimetic reaction vessels, and as additives in biocide and protective coatings. Halloysite nanotubes are available in thousands of tons, and remain sophisticated and novel natural nanomaterials which can be used for the loading of agents for metal and plastic anticorrosion and biocide protection.

16. Assessment of the basis for modeling releases from plutonium oxidation

Mahoney, L.A.; Mishima, J.

1990-08-01

Ideally, a model of the release of plutonium aerosols from plutonium during oxidation or combustion should begin from a description of the plutonium material and its surroundings and proceed unequivocally to a situation-dependent estimate of the amount of oxide released and its size distribution. Such a model would need to provide a description of the heat- and mass-transfer processes involved and link them directly to the rate of aerosol production. The first step, the description of heat and mass transfer, is more easily achieved from current information than the second, the aerosol release. The sections of this report titled Physical Fundamentals'' and Available Theoretical Information'' describe the approach that would be required for theoretical modeling. The Experimental Results'' section describes the information on aerosol releases, size distributions, peak temperatures, oxidation rates, and experimental conditions that we have gleaned from the existing experimental literature. The data is summarized and the bibliography lists the relevant literature that has and has not been reviewed. 42 refs., 10 figs., 6 tabs.

17. FORMULATION AND DISSOLUTION STUDY OF DILTIAZEM HYDROCHLORIDE IMMEDIATE RELEASE TABLETS

BRAHMAIAH BONTHAGARALA

2014-08-01

Full Text Available Objective: The main aim and objective of the work is to formulate immediate release tablets using different direct compression vehicles (DCV’S in different ratios. Methods: In the present study, design of oral immediate release tablets of Diltiazem hydrochloride by direct compression technique was carried out. Results: The main motive is to compare the dissolution profile of these formulations and conclude the best formulation which release drug at a faster rate . To determine the best fit dissolution profile for the dosage forms. Diltiazem hydrochloride tablets were formulated by using microcrystalline cellulose (diluent, potato starch, acacia (binder and magnesium stearate (lubricant. The granules were compressed into tablets and were subjected to dissolution studies. The dissolution profile of the formulation F2 was found to have better dissolution rate compared to others. Conclusion: The Invitro dissolution studies of all the formulations were conducted and the results were obtained, it was concluded that formulation F2 was the best with fast release of drug compared to others.

18. Control of contents and release kinetics in block copolymer vesicles

2005-03-01

Block copolymer vesicles have received considerable attention recently because of a wide range of potential applications. In our group, the thermodynamic aspects of vesicle formation, including curvature stabilization, as well as active loading and release from vesicles have been the focus of recent research. The vesicles are prepared from an amphiphilic diblock copolymer such as polystyrene-block-poly(acrylic acid) at a low pH (2.5) by adding water to a solution in a common solvent; then the extenal pH is raised to 6.5, and the compound, such as doxorubicin or another amine, is added. Since the compund inside the vesicle becomes ionized at the low pH, it can only escape at a rate very much slower than that of the loading process. The permeability of the wall can be controlled by the presence of plasticizers for the polystyrene wall; the plasticizers partition between the wall and the external aqueous solution with a known partition coefficient, and can be removed from the wall by dialysis. Release is then studied under perfect sink conditions and is diffusional. It is noteworthy that the rates of both loading and release can be varied by more than two orders of magnitude by controlling the plasticizer content. Also, between the loading and release processes, the vesicle wall can be hardened by removal of the plasticizer by dialysis. This degree of control makes block copolymer vesicles a promising delivery vehicle for a range of materials, including drugs.

19. Modulating drug release from gastric-floating microcapsules through spray-coating layers.

Wei Li Lee

Full Text Available Floating dosage forms with prolonged gastric residence time have garnered much interest in the field of oral delivery. However, studies had shown that slow and incomplete release of hydrophobic drugs during gastric residence period would reduce drug absorption and cause drug wastage. Herein, a spray-coated floating microcapsule system was developed to encapsulate fenofibrate and piroxicam, as model hydrophobic drugs, into the coating layers with the aim of enhancing and tuning drug release rates. Incorporating fenofibrate into rubbery poly(caprolactone (PCL coating layer resulted in a complete and sustained release for up to 8 h, with outermost non-drug-holding PCL coating layer serving as a rate-controlling membrane. To realize a multidrug-loaded system, both hydrophilic metformin HCl and hydrophobic fenofibrate were simultaneously incorporated into these spray-coated microcapsules, with metformin HCl and fenofibrate localized within the hollow cavity of the capsule and coating layer, respectively. Both drugs were observed to be completely released from these coated microcapsules in a sustained manner. Through specific tailoring of coating polymers and their configurations, piroxicam loaded in both the outer polyethylene glycol and inner PCL coating layers was released in a double-profile manner (i.e. an immediate burst release as the loading dose, followed by a sustained release as the maintenance dose. The fabricated microcapsules exhibited excellent buoyancy in simulated gastric fluid, and provided controlled and sustained release, thus revealing its potential as a rate-controlled oral drug delivery system.

20. Modulating drug release from gastric-floating microcapsules through spray-coating layers.

Lee, Wei Li; Tan, Jun Wei Melvin; Tan, Chaoyang Nicholas; Loo, Say Chye Joachim

2014-01-01

Floating dosage forms with prolonged gastric residence time have garnered much interest in the field of oral delivery. However, studies had shown that slow and incomplete release of hydrophobic drugs during gastric residence period would reduce drug absorption and cause drug wastage. Herein, a spray-coated floating microcapsule system was developed to encapsulate fenofibrate and piroxicam, as model hydrophobic drugs, into the coating layers with the aim of enhancing and tuning drug release rates. Incorporating fenofibrate into rubbery poly(caprolactone) (PCL) coating layer resulted in a complete and sustained release for up to 8 h, with outermost non-drug-holding PCL coating layer serving as a rate-controlling membrane. To realize a multidrug-loaded system, both hydrophilic metformin HCl and hydrophobic fenofibrate were simultaneously incorporated into these spray-coated microcapsules, with metformin HCl and fenofibrate localized within the hollow cavity of the capsule and coating layer, respectively. Both drugs were observed to be completely released from these coated microcapsules in a sustained manner. Through specific tailoring of coating polymers and their configurations, piroxicam loaded in both the outer polyethylene glycol and inner PCL coating layers was released in a double-profile manner (i.e. an immediate burst release as the loading dose, followed by a sustained release as the maintenance dose). The fabricated microcapsules exhibited excellent buoyancy in simulated gastric fluid, and provided controlled and sustained release, thus revealing its potential as a rate-controlled oral drug delivery system.

1. Release of segregated nuclides from spent fuel

Johnson, L.H.; Tait, J.C. [Atomic Energy Canada Ltd., Pinawa, MB (Canada). Whiteshell Laboratories

1997-10-01

The potential release of fission and activation products from spent nuclear fuel into groundwater after container failure in the Swedish deep repository is discussed. Data from studies of fission gas release from representative Swedish BWR fuel are used to estimate the average fission gas release for the spent fuel population. Information from a variety of leaching studies on LWR and CANDU fuel are then reviewed as a basis for estimating the fraction of the inventory of key radionuclides that could be released preferentially (the Instant Release Fraction of IRF) upon failure of the fuel cladding. The uncertainties associated with these estimates are discussed. 33 refs, 6 figs, 3 tabs.

2. Control of noradrenaline release from hippocampal synaptosomes

West, D.P.; Fillenz, M.

1981-10-01

Potassium-evoked tritiated noradrenaline (NA) release from hippocampal synaptosomes was measured with a superfusion method. A single 2-min high-K+ pulse released 39% of the vesicular NA by a Ca2+-dependent mechanism: the Ca2+-independent release was negligible. After changing the vesicular NA store size by pretreating rats with either alpha-methyl-para-tyrosine, 500 mg/kg, or tranylcypromine, 10 mg/kg, a single K+ pulse released a constant percentage of the vesicular NA. With two K+ pulses, however, there was a reduction in the percentage of vesicular NA released in response to the second pulse.

3. Characterization and in vitro release studies of tetracycline and rolitetracycline imobilized on anionic collagen membranes

Gilberto Goissis

2009-03-01

Full Text Available This work reports the covalent immobilization of tetracycline and rolitetracycline over anionic collagen membranes and the drug release studies as an effort to develop a two stage drug release based on diffusion (fast release and on the rate of membrane biodegradation (slow release. Independent from casting conditions antibiotics incorporated by dispersion were released in the range from 80 to 100% within 7 hours in concentrations significantly higher than those described for the prevention of bacterial growth. Antibiotic release within this period was predominantly diffusion controlled. Covalent immobilization by a modified azide procedure occurred with preservation of collagen structure independently from pH of casting and reaction conditions. Its expected that anionic collagen membranes with dispersed and covalently bound rolitetracycline or tetracycline, in association with conventional therapy, may significantly reduce membrane induced infections observed post-implantation, one of the major problem associated with periodontal ligaments reconstruction by the Guided Tissue Regeneration procedure.

4. A Preliminary Study on Natural Matrix Materials for Controlled Release Nitrogen Fertilizers

DU Chang-Wen; ZHOU Jian-Min; WANG Huo-Yan; LI Shou-Tian

2004-01-01

A controlled release N fertilizer was developed by the carrier method using natural polysaccharides (PS)and urea. The results showed that mixing of PS and urea led to significant control of urea release. When a cross-linker (boric acid or glutaraldehyde) was added, a better control effect was observed. During a 30 min leaching time the nitrogen release rate from the controlled release fertilizer was nearly constant, which was significantly different from normal urea. One of the controlled release mechanisms was related to space resistance from a large molecular structure. Infrared (IR) analysis indicated that interaction of PS with urea was through a hydrogen bond or a covalent bond. These bonds created an α-helix or high molecular network fertilizer carrier system, which was another reason for a controlled nutrient release. Pot experiment showed that nitrogen use efficiency could increase significantly with a carrier fertilizer.

5. Numerical Modelling of Insulin and Amyloglucosidase Release from Swelling Ca-Alginate Beads

Rasmussen, Michael R.; Snabe, T.; Pedersen, Lars Haastrup

2003-01-01

The release of insulin hexamer (39 kD) and amyloglucosidase (AMG, 97 kD), entrapped in spherical Ca–alginate beads, was investigated. While the release of insulin could be described solely by diffusion this was not the case for the 1.6 (r m /r m) larger AMG protein, where rm is the Stokes......–Einstein effective molecular radius. Because the alginate bead size was not constant during the release experiments, it was hypothesised that in addition to the diffusional mass transfer, a non-negligible convective flow of liquid in or out of the beads was present due to swelling or shrinkage, respectively...... convective flow in the numerical model, release could be described more accurately. The numerical model was able to describe the release  characteristics from both shrinking, swelling, and non-swelling alginate beads. To evaluate the effect of bead swelling on the protein release rate, a swelling modulus...

6. The release of 14C—chlorsulfuron bound residue by autoclaving method and its identification

GUOJiangfeng; PINGXiaofei; 等

1999-01-01

When individual microorganisms were used to release bound pesticide resdues,it was ussually not take into full account whether the autoclaving method could lead to the release of bound residues.The soil containing bound 14C-chlorsulfuron residues was treated with an autoclave in this study.The results reveal that the bound 14C-chlorsulfuron residue can be released from the soil when treated with the autoclave and the release rate can be remarkably enhanced by adding water into the soil when subjected to such treatment.A TLC analysis showed that the released 14C-residue was one of the degraded products of 14C-chlorsulfuron.After derivatization and analysis using the GC-MS,the released 14C-residue was tentatively identified as 2-amnino-4-hydroxyl-6-methyl-1,3,5-triazine.

7. Release Kinetics of Urea from Polymer Coated Urea and Its Relationship with Coating Penetrability

ZHANG Hai-jun; WU Zhi-jie; CHEN Li-jun; LIANG Wen-ju

2003-01-01

Four kinds of polymer coated urea (PCU) were put in distilled water at 30C to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU could be divided into four stages: lag stage, swell stage, steady stage and decay stage. The release rate coefficient K, a measure of coating penetrability, was linearly increased at swell stage, but almost not variable at steady stage. At decay stage, the relation of K to time t could be described by the equation K＝ mtn-1(where m and n are the coefficients). When n＞1, the coating penetrability was gradually increased, and the urea release from PCU was accelerated; when n＝1, the coating penetrability was steady, and the urea release from PCU obeyed the first-order kinetics; and when n＜1, the coating penetrability was gradually decreased,and the urea release from PCU was delayed, resulting in a significant "tailing effect".

8. Poly (lactic-co-glycolic acid) controlled release systems: experimental and modeling insights

Hines, Daniel J.; Kaplan, David L.

2013-01-01

Poly-lactic-co-glycolic acid (PLGA) has been the most successful polymeric biomaterial for use in controlled drug delivery systems. There are several different chemical and physical properties of PLGA that impact the release behavior of drugs from PLGA delivery devices. These properties must be considered and optimized in drug release device formulation. Mathematical modeling is a useful tool for identifying, characterizing, and predicting the mechanisms of controlled release. The advantages and limitations of poly (lactic-co-glycolic acid) for controlled release are reviewed, followed by a review of current approaches in controlled release technology that utilize PLGA. Mathematical modeling applied towards controlled release rates from PLGA-based devices will also be discussed to provide a complete picture of state of the art understanding of the control achievable with this polymeric system, as well as the limitations. PMID:23614648

9. Poly(lactic-co-glycolic) acid-controlled-release systems: experimental and modeling insights.

Hines, Daniel J; Kaplan, David L

2013-01-01

Poly(lactic-co-glycolic acid) (PLGA) has been the most successful polymeric biomaterial used in controlled drug delivery systems. There are several different chemical and physical properties of PLGA that impact the release behavior of drugs from PLGA delivery devices. These properties must be considered and optimized in the formulation of drug release devices. Mathematical modeling is a useful tool for identifying, characterizing, and predicting mechanisms of controlled release. The advantages and limitations of poly(lactic-co-glycolic acid) for controlled release are reviewed, followed by a review of current approaches in controlled-release technology that utilize PLGA. Mathematical modeling applied toward controlled-release rates from PLGA-based devices also will be discussed to provide a complete picture of a state-of-the-art understanding of the control that can be achieved with this polymeric system, as well as the limitations.

10. A central theory of preterm and term labor: putative role for corticotropin-releasing hormone.

Majzoub, J A; McGregor, J A; Lockwood, C J; Smith, R; Taggart, M S; Schulkin, J

1999-01-01

Near the end of human pregnancy the concentration of placental corticotropin-releasing hormone in maternal blood rises exponentially. The rate of elevation of corticotropin-releasing hormone and its duration through time have been linked to the time of onset of labor. Paradoxically, although glucocorticoids are known to inhibit corticotropin-releasing hormone production within the hypothalamic-pituitary-adrenal axis, cortisol actually increases corticotropin-releasing hormone levels in several areas outside the hypothalamus, including the placenta. Placental corticotropin-releasing hormone may be an important component of a system that controls the normal maturation of the fetus and signals the initiation of labor. Abnormal elevations in corticotropin-releasing hormone, which may be a hormonal response to stressors arising in either the mother, placenta, or fetus, may prove to participate in the premature onset of parturition.

11. Composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose for drug controlled release.

Pavaloiu, Ramona-Daniela; Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Dobre, Tanase

2014-07-01

Mono and multilayer composite films of poly(vinyl alcohol)-chitosan-bacterial cellulose (PVA/chitosan/BC) have been prepared to achieve controlled release of ibuprofen sodium salt (IbuNa) as model drug. The composite films have been characterized by Fourier transformed infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Surface morphology was investigated by scanning electron microscopy (SEM). Equilibrium swelling was measured in water at two different pH values and in vitro release of IbuNa in pH 1.2 and pH 7.4 media was studied. The release experiments revealed that drug release is pH sensitive. The release kinetics of IbuNa could be described by the Fickian model of diffusion with a good agreement. The IbuNa release rate was decreasing for all the films as the BC concentration was increased in the films composition, the decrease being higher for the multilayer films.

12. Release behavior and kinetic evaluation of berberine hydrochloride from ethyl cellulose/chitosan microspheres

Zhou, Hui-Yun; Cao, Pei-Pei; Zhao, Jie; Wang, Zhi-Ying; Li, Jun-Bo; Zhang, Fa-Liang

2014-12-01

Novel ethyl cellulose/chitosan microspheres (ECCMs) were prepared by the method of w/o/w emulsion and solvent evaporation. The microspheres were spherical, adhesive, and aggregated loosely with a size not bigger than 5 μm. The drug loading efficiency of berberine hydrochloride (BH) loaded in microspheres were affected by chitosan (CS) concentration, EC concentration and the volume ratio of V(CS)/ V(EC). ECCMs prepared had sustained release efficiency on BH which was changed with different preparation parameters. In addition, the pH value of release media had obvious effect on the release character of ECCMs. The release rate of BH from sample B was only a little more than 30% in diluted hydrochloric acid (dHCl) and that was almost 90% in PBS during 24 h. Furthermore, the drug release data were fitted to different kinetic models to analyze the release kinetics and the mechanism from the microspheres. The released results of BH indicated that ECCMs exhibited non-Fickian diffusion mechanism in dHCl and diffusion-controlled drug release based on Fickian diffusion in PBS. So the ECCMs might be an ideal sustained release system especially in dHCl and the drug release was governed by both diffusion of the drug and dissolution of the polymeric network.

13. Quantifying the release of lactose from polymer matrix tablets with an amperometric biosensor utilizing cellobiose dehydrogenase.

Knöös, Patrik; Schulz, Christopher; Piculell, Lennart; Ludwig, Roland; Gorton, Lo; Wahlgren, Marie

2014-07-01

The release of lactose (hydrophilic) from polymer tablets made with hydrophobically modified poly(acrylic acid) (HMPAA) have been studied and compared to the release of ibuprofen, a hydrophobic active substance. Lactose is one of the most used excipients for tablets, but lactose release has not been widely studied. One reason could be a lack of good analytical tools. A novel biosensor with cellobiose dehydrogenase (CDH) was used to detect the lactose release, which has a polydiallyldimethylammonium chloride (PDADMAC) layer that increases the response. A sample treatment using polyethylenimine (PEI) was developed to eliminate possible denaturants. The developed methodology provided a good approach to detect and quantify the released lactose. The release was studied with or without the presence of a model amphiphilic substance, sodium dodecyl sulphate (SDS), in the release medium. Ibuprofen showed very different release rates in the different media, which was attributed to hydrophobic interactions between the drug, the HMPAA and the SDS in the release medium. The release of hydrophilic lactose, which did not associate to any of the other components, was rapid and showed only minor differences. The new methodology provides a useful tool to further evaluate tablet formulations by a relatively simple set of experiments.

14. The Smart Aerial Release Machine, a Universal System for Applying the Sterile Insect Technique

Mubarqui, Ruben Leal; Perez, Rene Cano; Kladt, Roberto Angulo; Lopez, Jose Luis Zavala; Parker, Andrew; Seck, Momar Talla; Sall, Baba; Bouyer, Jérémy

2014-01-01

Background Beyond insecticides, alternative methods to control insect pests for agriculture and vectors of diseases are needed. Management strategies involving the mass-release of living control agents have been developed, including genetic control with sterile insects and biological control with parasitoids, for which aerial release of insects is often required. Aerial release in genetic control programmes often involves the use of chilled sterile insects, which can improve dispersal, survival and competitiveness of sterile males. Currently available means of aerially releasing chilled fruit flies are however insufficiently precise to ensure homogeneous distribution at low release rates and no device is available for tsetse. Methodology/Principal Findings Here we present the smart aerial release machine, a new design by the Mubarqui Company, based on the use of vibrating conveyors. The machine is controlled through Bluetooth by a tablet with Android Operating System including a completely automatic guidance and navigation system (MaxNav software). The tablet is also connected to an online relational database facilitating the preparation of flight schedules and automatic storage of flight reports. The new machine was compared with a conveyor release machine in Mexico using two fruit flies species (Anastrepha ludens and Ceratitis capitata) and we obtained better dispersal homogeneity (% of positive traps, p<0.001) for both species and better recapture rates for Anastrepha ludens (p<0.001), especially at low release densities (<1500 per ha). We also demonstrated that the machine can replace paper boxes for aerial release of tsetse in Senegal. Conclusions/Significance This technology limits damages to insects and allows a large range of release rates from 10 flies/km2 for tsetse flies up to 600 000 flies/km2 for fruit flies. The potential of this machine to release other species like mosquitoes is discussed. Plans and operating of the machine are provided to allow its

15. The smart aerial release machine, a universal system for applying the sterile insect technique.

Ruben Leal Mubarqui

Full Text Available Beyond insecticides, alternative methods to control insect pests for agriculture and vectors of diseases are needed. Management strategies involving the mass-release of living control agents have been developed, including genetic control with sterile insects and biological control with parasitoids, for which aerial release of insects is often required. Aerial release in genetic control programmes often involves the use of chilled sterile insects, which can improve dispersal, survival and competitiveness of sterile males. Currently available means of aerially releasing chilled fruit flies are however insufficiently precise to ensure homogeneous distribution at low release rates and no device is available for tsetse.Here we present the smart aerial release machine, a new design by the Mubarqui Company, based on the use of vibrating conveyors. The machine is controlled through Bluetooth by a tablet with Android Operating System including a completely automatic guidance and navigation system (MaxNav software. The tablet is also connected to an online relational database facilitating the preparation of flight schedules and automatic storage of flight reports. The new machine was compared with a conveyor release machine in Mexico using two fruit flies species (Anastrepha ludens and Ceratitis capitata and we obtained better dispersal homogeneity (% of positive traps, p<0.001 for both species and better recapture rates for Anastrepha ludens (p<0.001, especially at low release densities (<1500 per ha. We also demonstrated that the machine can replace paper boxes for aerial release of tsetse in Senegal.This technology limits damages to insects and allows a large range of release rates from 10 flies/km2 for tsetse flies up to 600,000 flies/km2 for fruit flies. The potential of this machine to release other species like mosquitoes is discussed. Plans and operating of the machine are provided to allow its use worldwide.

16. Rab3A deletion selectively reduces spontaneous neurotransmitter release at the mouse neuromuscular synapse.

Sons, Michèle S; Plomp, Jaap J

2006-05-17

Rab3A is a synaptic vesicle-associated GTP-binding protein thought to be involved in modulation of presynaptic transmitter release through regulation of vesicle trafficking and membrane fusion. Electrophysiological studies at central nervous system synapses of Rab3A null-mutant mice have indicated that nerve stimulation-evoked transmitter release and its short- and long-term modulation are partly dependent on Rab3A, whereas spontaneous uniquantal release is completely independent of it. Here, we studied the acetylcholine (ACh) release at the neuromuscular junction (NMJ) of diaphragm and soleus muscles from Rab3A-deficient mice with intracellular microelectrode methods. Surprisingly, we found 20-40% reduction of spontaneous ACh release but completely intact nerve action potential-evoked release at both high- and low-rate stimulation and during recovery from intense release. The ACh release induced by hypertonic medium was also unchanged, indicating that the pool of vesicles for immediate release is unaltered at the Rab3A-deficient NMJ. These results indicate a selective role of Rab3A in spontaneous transmitter release at the NMJ which cannot or only partly be taken over by the closely related Rab3B, Rab3C, or Rab3D isoforms when Rab3A is deleted. It has been hypothesized that Rab3A mutation underlies human presynaptic myasthenic syndromes, in which severely reduced nerve action potential-evoked ACh release at the NMJ causes paralysis. Our observation that Rab3A deletion does not reduce evoked ACh release at any stimulation rate at the mouse NMJ, argues against this hypothesis.

17. PECTIN MICROGELS CONTAINING SYNTHETIC POLYMERS BASED ON NANOCAPSULES FOR THE CONTROLLED RELEASE OF INDOMETHACIN

Mihaela HOLBAN

2015-12-01

Full Text Available Nanocapsule-based Eudragit RS100 and Eudragit E100 containing indomethacin have been prepared. The nanosuspensions have been included into pectin microgels of different polysaccharide concentrations, 28-61 µm-ranged polymer microgels with size and size polydispersity highly depending on the pectin amount being thus obtained. Study of the drug release revealed that indomethacin was released at a slower and more controlled rate from the microgels containing nanocapsules than from the empty pectin microgels. Also, the rate of released indomethacin increased with the augmentation of pectin amount into the microgels.

18. Plasma immersion ion implantation for reducing metal ion release

Diaz, C.; Garcia, J. A.; Maendl, S.; Pereiro, R.; Fernandez, B.; Rodriguez, R. J. [Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain); Leibniz-Institut fuer Oberflaechenmodifizierung, 04318 Leipzig (Germany); Universidad de Oviedo, Departamento Quimica Fisica y Analitica (Spain); Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain)

2012-11-06

Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

19. The 2013 Release of Cloudy

Ferland, G J; van Hoof, P A M; Williams, R J R; Abel, N P; Lykins, M L; Shaw, Gargi; Henney, W J; Stancil, P C

2013-01-01

This is a summary of the 2013 release of the plasma simulation code Cloudy. Cloudy models the ionization, chemical, and thermal state of material that may be exposed to an external radiation field or other source of heating, and predicts observables such as emission and absorption spectra. It works in terms of elementary processes, so is not limited to any particular temperature or density regime. This paper summarizes advances made since the last major review in 1998. Much of the recent development has emphasized dusty molecular environments, improvements to the ionization / chemistry solvers, and how atomic and molecular data are used. We present two types of simulations to demonstrate the capability of the code. We consider a molecular cloud irradiated by an X-ray source such as an Active Nucleus and show how treating EUV recombination lines and the full SED affects the observed spectrum. A second example illustrates the very wide range of particle and radiation density that can be considered.

20. Release of RANKERN 16A
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5401761531829834, "perplexity": 8762.44622191799}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257649931.17/warc/CC-MAIN-20180324054204-20180324074204-00402.warc.gz"}