text:
State Restrictions on Methyl Tertiary Butyl Ether (released in AEO2006)
Reports and Publications (EIA)
By the end of 2005, 25 states had barred, or passed laws banning, any more than trace levels of methyl tertiary butyl ether (MTBE) in their gasoline supplies, and legislation to ban MTBE was pending in 4 others. Some state laws address only MTBE; others also address ethers such as ethyl tertiary butyl ether (ETBE) and tertiary amyl methyl ether (TAME). Annual Energy Outlook 2006 assumes that all state MTBE bans prohibit the use of all ethers for gasoline blending.
Enhanced diisobutene production in the presence of methyl tertiary butyl ether
Smith, Jr., Lawrence A. (Bellaire, TX)
In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C.sub.4 hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether.
Enhanced diisobutene production in the presence of methyl tertiary butyl ether
Smith, L.A. Jr.
In the liquid phase reaction of isobutene in the presence of resin cation exchange resins with itself in a C[sub 4] hydrocarbon stream to form dimers, the formation of higher polymers, oligomers, and co-dimer by-products is suppressed by the presence of 0.0001 to 1 mole per mole of isobutene of methyl tertiary butyl ether. 1 fig.
Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012 (January 2014)
Broader source: Energy.gov [DOE]
The "Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012" document is a compilation of publicly-available data on transmission constraints and congestion for the period 2009 through 2012.
Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012 United States Department of Energy Washington, DC 20585 January 2014 U.S. Department of Energy | January 2014 Note to Reader This document provides a summary of publicly available information regarding transmission constraints and congestion from 2009-2012. This is not the Department's third National Electric Transmission Congestion Study, which will be released separately. Providing relevant
Activation of water soluble amines by halogens for trapping methyl radioactive iodine from air streams
Deitz, Victor R.; Blachly, Charles H.
Gas adsorbent charcoals impregnated with an aqueous solution of the reaction product of a tertiary amine and elemental iodine or bromine are better than 99 per cent efficient in trapping methyl iodine.sup.131. The chemical addition of iodine or bromine to the tertiary amine molecule increases the efficiency of the impregnated charcoal as a trapping agent, and in conjunction with the high flash point of the tertiary amine raises the ignition temperature of the impregnated charcoal.
Cooperative Tertiary Interaction Network Guides RNA Folding
Behrouzi, Reza; Roh, Joon Ho; Kilburn, Duncan; Briber, R.M.; Woodson, Sarah A.
Noncoding RNAs form unique 3D structures, which perform many regulatory functions. To understand how RNAs fold uniquely despite a small number of tertiary interaction motifs, we mutated the major tertiary interactions in a group I ribozyme by single-base substitutions. The resulting perturbations to the folding energy landscape were measured using SAXS, ribozyme activity, hydroxyl radical footprinting, and native PAGE. Double- and triple-mutant cycles show that most tertiary interactions have a small effect on the stability of the native state. Instead, the formation of core and peripheral structural motifs is cooperatively linked in near-native folding intermediates, and this cooperativity depends on the native helix orientation. The emergence of a cooperative interaction network at an early stage of folding suppresses nonnative structures and guides the search for the native state. We suggest that cooperativity in noncoding RNAs arose from natural selection of architectures conducive to forming a unique, stable fold.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Controlling DNA Methylation Though life on earth is composed of a diverse range of organisms, some with many different types of tissues and cells, all these are encoded by a molecule we call DNA. The information required to build a protein is stored in DNA within the cells. Not all the message in the DNA is used in each cell and not all the message is used all the time. During cell differentiation, the cells become dedicated for their specific function which involves selectively activating some
Aqueous flooding methods for tertiary oil recovery
Peru, Deborah A.
A method of aqueous flooding of subterranean oil bearing formation for tertiary oil recovery involves injecting through a well into the formation a low alkaline pH aqueous sodium bicarbonate flooding solution. The flooding solution's pH ranges from about 8.25 to 9.25 and comprises from 0.25 to 5 weight percent and preferably about 0.75 to 3.0 weight percent of sodium bicarbonate and includes a petroleum recovery surfactant of 0.05 to 1.0 weight percent and between 1 and 20 weight percent of sodium chloride. After flooding, an oil and water mixture is withdrawn from the well and the oil is separated from the oil and water mixture.
Combustion characterization of methylal in reciprocating engines
Dodge, L.; Naegeli, D.
Methylal, CH{sub 3}OCH{sub 2}OCH{sub 3}, also known as dimethoxy-methane, is unique among oxygenates in that it has a low autoignition temperature, no carbon-carbon bonds, and is soluble in middle distillate fuels. Because of these properties, methylal has been shown to be a favorable fuel additive for reducing smoke in diesel engines. Recent measurements of ignition delay times indicate that methylal has a cetane number in the range of 45-50, which is compatible with diesel fuels. Engine tests have shown that adding methylal to diesel fuel significantly reduces smoke emissions. Gaseous emissions and combustion efficiencies obtained with methylal/diesel fuel blends remain essentially the same as those measured using neat diesel fuel. Lubricity measurements of methylal/diesel fuel blends with a ball on cylinder lubrication evaluator (BOCLE) show that methylal improves the lubricity of diesel fuel. Even though additions of methylal lower the fuel viscosity, the results of the BOCLE tests indicate that the methylal/diesel fuel blends cause less pump wear than neat diesel fuel. The one drawback is that methylal has a low boiling point (42{degrees}C) and a relatively high vapor pressure. As a result, it lowers the flash point of diesel fuel and causes a potential fuel tank flammability hazard. One solution to this increased volatility is to make polyoxymethylenes with the general formula of CH{sub 3}O(CH{sub 2}O){sub x}CH{sub 3} where x > 2. The molecules are similar to methylal, but have higher molecular weights and thus higher viscosities and substantially lower vapor pressures. Therefore, their flash points will be compatible with regular diesel fuel. The polyoxymethylenes are expected to have combustion properties similar to methylal. It is theorized that by analogy with hydrocarbons, the ignition quality (i.e., cetane number) of the polyoxymethylenes will be better than that of methylal.
Seaborg, G.T.
A process is described for extracting tetravalent plutonium from an aqueous acid solution with methyl ethyl ketone, methyl isobutyl ketone, or acetophenone and with the extraction of either tetravalent or hexavalent plutonium into menthone. (AEC)
Stable isotopes composition of precipitation fallen over Cluj-Napoca, Romania, between 2009-2012
Puscas, R.; Feurdean, V.; Simon, V.
The paper presents the deuterium and oxygen 18 content from All precipitations events, which have occured over Cluj-Napoca, Romania from 2009 until 2012. Time series for δ{sup 2}H and δ{sup 18}O values point out both the seasonal variation that has increased amplitude reflecting the continental character of the local climate as well as dramatic variations of isotopic content of successive precipitation events, emphasizing the anomalous values. These fluctuations are the footprint of the variations and trends in climate events. Local Meteoric Water Line (LMWL), reflecting the δ{sup 2}H - δ{sup 18}O correlation, has the slop and the intercept slightly deviated from the GMWL, indicating that the dominant process affecting local precipitations are close to the equilibrium condition. LMWL has a slope smaller then that of the GMWL in the warm season due to lower humidity and a slope closest to the slop of GMWL in cold season with high humidity. The δ{sup 2}H and δ{sup 18}O values both for the precipitation events and monthly mean values are positively correlated with the temperature values with a very good correlation factor. The values of δ{sup 2}H and δ{sup 18}O are not correlated with amount of precipitation, the 'amount effect' of isotopic composition of precipitation is not observed for this site.
Method and apparatus for secondary and tertiary recovery of hydrocarbons
Rivas, N.; Beichel, R.
This patent describes an apparatus for secondary and tertiary recovery of hydrocarbons from oil fields comprising: a. a bipropellant generator capable of producing exhaust gases at supercritical pressures and temperatures; b. transport means for carrying the exhaust gases into a well bore, at least a portion of the well bore extending into a hydrocarbon bearing formation from which hydrocarbons are to be recovered; c. means for introducing water into the transport means; and d. a water cooling jacket extending into at least the upper portion of the well bore, the center of the cooling jacket receiving the exhaust gases from the transport means, means being provided for the introduction of chemical additives through a portion of the cooling jacket. A process is described for secondary and tertiary recovery of hydrocarbons from geological formations comprising: a. providing a well bore extending at least into the strata of the geologic formation containing the hydrocarbons to be recovered; b. providing at least the upper portion of the well bore with a cooling jacket, the cooling jacket being provided with a central, open portion; c. generating gases at supercritical temperatures and pressures; d. introducing water into the supercritical gases to form steam; e. forcing the mixture of supercritical combustion gases and steam through the central open portion of the cooling jacket and the well bore into the hydrocarbon strata; and f. adding chemical additives to the mixture of combustion gases and steam below the cooling jacket.
Methylal and Methylal-Diesel Blended Fuels from Use In Compression-Ignition Engines
Keith D. Vertin; James M. Ohi; David W. Naegeli; Kenneth H. Childress; Gary P. Hagen; Chris I. McCarthy; Adelbert S. Cheng; Robert W. Dibble
Gas-to-liquids catalytic conversion technologies show promise for liberating stranded natural gas reserves and for achieving energy diversity worldwide. Some gas-to-liquids products are used as transportation fuels and as blendstocks for upgrading crude derived fuels. Methylal (CH{sub 3}-O-CH{sub 2}-O-CH{sub 3}) also known as dimethoxymethane or DMM, is a gas-to-liquid chemical that has been evaluated for use as a diesel fuel component. Methylal contains 42% oxygen by weight and is soluble in diesel fuel. The physical and chemical properties of neat methylal and for blends of methylal in conventional diesel fuel are presented. Methylal was found to be more volatile than diesel fuel, and special precautions for distribution and fuel tank storage are discussed. Steady state engine tests were also performed using an unmodified Cummins 85.9 turbocharged diesel engine to examine the effect of methylal blend concentration on performance and emissions. Substantial reductions of particulate matter emissions h ave been demonstrated 3r IO to 30% blends of methylal in diesel fuel. This research indicates that methylal may be an effective blendstock for diesel fuel provided design changes are made to vehicle fuel handling systems.
West Hackberry Tertiary Project. Annual report, September 3, 1997--September 2, 1998
Gillham, T.H.
The following report is the Project Management Plan for the fifth year of the West Hackberry Tertiary Project. The West Hackberry Tertiary Project is one of four mid-term projects selected by the United States Department of Energy (DOE) as part of the DOE`s Class 1 Program for the development of advance recovery technologies in fluvial dominated deltaic reservoirs. The West Hackberry Tertiary Project is a field test of the idea that air injection can be combined with the Double Displacement Process to produce a low cost tertiary recovery process which is economic at current oil prices. The Double Displacement Process is the gas displacement of a water invaded oil column for the purpose of recovering tertiary oil by gravity drainage. The Double Displacement Process is based upon the concept that in fields such as West Hackberry waterdrive recoveries are typically 50%-60% of the original oil in place while gravity drainage recoveries average 80%-90% of the original oil in place. Therefore, by injecting a gas into a watered out reservoir, a gas cap will form an additional oil can be recovered due to gravity drainage. Although the Double Displacement Process has been shown to be successful in recovering tertiary oil in other fields, this project will be the first to utilize air injection in the Double Displacement Process. The use of air injection in this process combines the benefits of air`s low cost and universal accessibility with the potential for accelerated oil recovery due to the combustion process. If successful, this project will demonstrate that the use of air injection in the Double Displacement Process will result in an economically viable tertiary process in reservoirs where tertiary oil recovery is presently uneconomical.
West Hackberry tertiary project. Annual report, September 3, 1994--September 2, 1995
Gillham, T.; Cerveny, B.; Turek, E.
The West Hackberry Tertiary Project is a field test of the idea that air injection can be combined with the Double Displacement Process to produce a low cost tertiary recovery process which is economic at current oil prices. The Double Displacement Process is the gas displacement of a water invaded oil column for the purpose of recovering tertiary oil by gravity drainage. The Double Displacement Process is based upon the concept that in fields such as West Hackberry waterdrive recoveries are typically 50%-60% of the original oil in place while gravity drainage recoveries average 80%-90% of the original oil in place. Therefore, by injecting a gas into a watered out reservoir, a gas cap will form and additional oil can be recovered due to gravity drainage. Although the Double Displacement Process has been shown to be successful in recovering tertiary oil in other fields, this project will be the first to utilize air injection in the Double Displacement Process. The use of air injection in this process combines the benefits of air`s low cost and universal accessibility with the potential for accelerated oil recovery due to the combustion process. If successful, this project will demonstrate that the use of air injection in the Double Displacement Process will result in an economically viable tertiary process in reservoirs where tertiary oil recovery is presently uneconomical.
Low temperature synthesis of methyl formate
Mahajan, Devinder; Slegeir, William A.; Sapienza, Richard S.; O'Hare, Thomas E.
A gas reaction process for the preferential production of methyl formate over the co-production of methanol wherein the reactant ratio of CO/H.sub.2 is upgraded and this reaction takes place at low temperatures of 50.degree.-150.degree. C. and moderate pressures of .gtoreq.100 psi.
Modulation of histone methylation and MLH1 gene silencing by...
Office of Scientific and Technical Information (OSTI)
... Subject: 60 APPLIED LIFE SCIENCES; ARGININE; CARCINOGENS; CHROMIUM; DNA DAMAGES; GENES; HUMAN POPULATIONS; LUNGS; LYSINE; METHYLATION; NEOPLASMS; OCCUPATIONAL EXPOSURE; PROMOTERS ...
Tension-compression-tension tertiary twins in coarse-grained polycrystalline pure magnesium at room temperature
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Yu, Qin; Jiang, Yanyao; Wang, Jian
Using electron backscatter diffraction, the microstructural features of tension–compression–tension (T–C–T) tertiary twins are studied in coarse-grained pure polycrystalline magnesium subjected to monotonic compression along the extrusion direction in ambient air. T–C–T tertiary twins are developed due to the formation of a compression–tension double twin inside a primary tension twin. All the observed T–C–T twin variants are of TiCjTj type. TiCi+1Ti+1 (or TiCi–1Ti–1) variants are observed more frequently than TiCi+2Ti+2 (or TiCi–2Ti–2) variants. Moreover, the number of tertiary twin lamellae increases with the applied compressive strain.
An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion
Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T
Biodiesel is typically a mixture of long chain fatty acid methyl esters for use in compression ignition engines. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This research study presents new combustion data for methyl decanoate in an opposed-flow diffusion flame. An improved detailed chemical kinetic model for methyl decanoate combustion is developed, which serves as the basis for deriving a skeletal mechanism via the direct relation graph method. The novel skeletal mechanism consists of 648 species and 2998 reactions. This mechanism well predicts the methyl decanoate opposed-flow diffusion flame data. The results from the flame simulations indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.
Lithium Methyl Carbonate as a Reaction Product of Metallic Lithiumand...
Office of Scientific and Technical Information (OSTI)
Lithium methyl carbonate is only one of the components, the others being lithium oxalate and lithium methoxide. Authors: Zhuang, Guorong V. ; Yang, Hui ; Ross Jr., Philip N. ; Xu, ...
Conversion of Levulinic Acid to Methyl Tetrahydrofuran - Energy...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
acid is a highly desirable renewable chemical platform, which, using this process, can be converted into Methyl Tetrahydrofuran (Me-THF) with reasonable yield. The...
Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate
Senent, M. L.; Puzzarini, C.; Hochlaf, M.; Domínguez-Gómez, R.; Carvajal, M.
Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH{sub 3}-S-CHO (MSCHO) and O-methyl thioformate CH{sub 3}-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH{sub 3}-S-CHO represents the most stable structure lying 4372.2 cm{sup −1} below cis-CH{sub 3}-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm{sup −1}) than for MOCHS (1963.6 cm{sup −1}). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V{sub 3}(cis) are determined to be 139.7 cm{sup −1} (CH{sub 3}-S-CHO) and 670.4 cm{sup −1} (CH{sub 3}-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm{sup −1} for CH{sub 3}-S-CHO and negligible for CH{sub 3}-O-CHS.
Production of methyl-vinyl ketone from levulinic acid
Dumesic, James A.; West; Ryan M.
A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.
Host cells and methods for producing 3-methyl-2-buten-1-ol, 3-methyl-3-buten-1-ol, and 3-methyl-butan-1-ol
Chou, Howard H.; Keasling, Jay D.
The invention provides for a method for producing a 5-carbon alcohol in a genetically modified host cell. In one embodiment, the method comprises culturing a genetically modified host cell which expresses a first enzyme capable of catalyzing the dephosphorylation of an isopentenyl pyrophosphate (IPP) or dimethylallyl diphosphate (DMAPP), such as a Bacillus subtilis phosphatase (YhfR), under a suitable condition so that 5-carbon alcohol is 3-methyl-2-buten-1-ol and/or 3-methyl-3-buten-1-ol is produced. Optionally, the host cell may further comprise a second enzyme capable of reducing a 3-methyl-2-buten-1-ol to 3-methyl-butan-1-ol, such as a reductase.
Field pilot tests for tertiary recovery using butane and propane injection
Pacheco, E.F.; Garcia, A.I.
This work describes a pilot project for tertiary recovery of liquid hydrocarbons through LPG injection in water-out sections of the Bolivar reservoir in La Pena Field, Santa Cruz, Boliva. The promising results obtained in the initial field miscibility tests, as well as the results from a mathematical model built to stimulate and evaluate the tertiary recovery project, directed subsequent work into a cyclic scheme for enhanced recovery. This scheme is explained and injection production data is presented. Field facilities built to handle both the injected LPG and the produced oil-LPG mixture are described. The oil/LPG ratio and the LPG recovered/injected fraction are the main factors measured in this to make further considerations for a full scale project.
Laramide thrusting and Tertiary deformation Tierra Caliente, Michoacan and Guerrero States, southwestern Mexico
Johnson, C.A.; Harrison, C.G.A. ); Lang, H. ); Barros, J.A.; Cabral-Cano, E.
Field investigations and detailed interpretations of Landsat Thematic Mapper images are in progress to improve understanding of regional structure and tectonics of the southernmost extension of the North American cordillera. Two areas have been selected within the Ciudad Altamirano 1:250,000 topographical sheet for geologic mapping and structural interpretation at 1:50,000 scale. The authors results to date require modification of previous ideas concerning the style and timing of deformations, the role and timing of terrane accretion in the overall tectonic history of the region, and the importance of southern Mexico to investigations of the tectonic evolution of the plates in the region. The relative sequence of deformation in the area correlates well with variations in relative motion between North America and plates in the Pacific. Post-Campanian thrusts and generally eastward-verging folds deformed the Mesozoic sequence during the (Laramide equivalent) Hidalgoan orogeny, associated with high-velocity east-west convergence with the Farallon plate that began about 70 Ma. The resulting unconformity was covered by the Tertiary Balsas Formation, a thick sequence of mostly continental clastics. The Tertiary stratigraphy is regionally and sometimes locally variable, but it can be divided into two members. The lower member is relatively volcanic poor and more deformed, and it lies below a regionally significant mid-Tertiary unconformity, which may mark a change to northeast-directed convergence with the Farallon plate sometime prior to 40 Ma. Continued mid-Tertiary deformation in southern Mexico may be related to eastward movement of the Chortis block and the resulting truncation of the Pacific margin of Mexico. The authors also suggest a tentative correlation between the volcaniclastic member of the Lower Cretaceous San Lucas Formation and the protolith of the Roca Verde metamorphics to the east.
Role of methyl groups in dynamics and evolution of biomolecules
Nickels, Jonathan D [ORNL; Curtis, J. E. [National Institute of Standards and Technology (NIST), Gaithersburg, MD; Oneill, Hugh [Oak Ridge National Laboratory (ORNL); Sokolov, Alexei P [ORNL
Recent studies have discovered strong differences between the dynamics of nucleic acids (RNA and DNA) and proteins, especially at low hydration and low temperatures. This difference is caused primarily by dynamics of methyl groups that are abundant in proteins, but are absent or very rare in RNA and DNA. In this paper, we present a hypothesis regarding the role of methyl groups as intrinsic plasticizers in proteins and their evolutionary selection to facilitate protein dynamics and activity. We demonstrate the profound effect methyl groups have on protein dynamics relative to nucleic acid dynamics, and note the apparent correlation of methyl group content in protein classes and their need for molecular flexibility. Moreover, we note the fastest methyl groups of some enzymes appear around dynamical centers such as hinges or active sites. Methyl groups are also of tremendous importance from a ydrophobicity/folding/entropy perspective. These significant roles, however, complement our hypothesis rather than preclude the recognition of methyl groups in the dynamics and evolution of biomolecules.
Dcm methylation is detrimental to plasmid transformation in Clostridium thermocellum
Guss, Adam M; Olson, Daniel G.; Caiazza, Nicky; Lynd, Lee R
BACKGROUND: Industrial production of biofuels and other products by cellulolytic microorganisms is of interest but hindered by the nascent state of genetic tools. Although a genetic system for Clostridium thermocellum DSM1313 has recently been developed, available methods achieve relatively low efficiency and similar plasmids can transform C. thermocellum at dramatically different efficiencies. RESULTS: We report an increase in transformation efficiency of C. thermocellum for a variety of plasmids by using DNA that has been methylated by Escherichia coli Dam but not Dcm methylases. When isolated from a dam+ dcm+ E. coli strain, pAMG206 transforms C. thermocellum 100-fold better than the similar plasmid pAMG205, which contains an additional Dcm methylation site in the pyrF gene. Upon removal of Dcm methylation, transformation with pAMG206 showed a four- to seven-fold increase in efficiency; however, transformation efficiency of pAMG205 increased 500-fold. Removal of the Dcm methylation site from the pAM205 pyrF gene via silent mutation resulted in increased transformation efficiencies equivalent to that of pAMG206. Upon proper methylation, transformation efficiency of plasmids bearing the pMK3 and pB6A origins of replication increased ca. three orders of magnitude. CONCLUSION: E. coli Dcm methylation decreases transformation efficiency in C. thermocellum DSM1313. The use of properly methylated plasmid DNA should facilitate genetic manipulation of this industrially relevant bacterium.
West Hackberry Tertiary Project. Quarterly technical progress report, January 1, 1996--March 31, 1996
Gillham, T.; Cerveny, B.; Turek, E.
The goal of the West Hackberry Tertiary Project is to demonstrate the technical and economic feasibility of combining air injection with the Double Displacement Process for tertiary oil recovery. The Double Displacement Process is the gas displacement of a water invaded oil column for the purpose of recovering oil through gravity drainage. The novel aspect of this project is the use of air as the injection fluid. The target reservoir for the project is the Camerina C-1,2,3 sand located on the West Flank of West Hackberry Field in Cameron Parish, Louisiana. If successful, this project will demonstrate that the use of air injection in the Double Displacement Process can economically recover oil in reservoirs where tertiary oil recovery is presently uneconomic. The first quarter of 1996 was outstanding both in terms of volume of air injected and low cost operations. More air was injected during this quarter than in any preceding quarter. The compressors experienced much improved run time with minimal repairs. Low operating costs resulted from no repairs required for injection or production wells. A discussion of the following topics are contained herein: (1) performance summary for the injection and production wells, (2) air compressor operations, (3) updated bottom hole pressure data, (4) technology transfer activities and (5) plans for the upcoming quarter.
Tension-compression-tension tertiary twins in coarse-grained polycrystalline pure magnesium at room temperature
Yu, Qin; Jiang, Yanyao; Wang, Jian
Using electron backscatter diffraction, the microstructural features of tension–compression–tension (T–C–T) tertiary twins are studied in coarse-grained pure polycrystalline magnesium subjected to monotonic compression along the extrusion direction in ambient air. T–C–T tertiary twins are developed due to the formation of a compression–tension double twin inside a primary tension twin. All the observed T–C–T twin variants are of TiCjTj type. TiCi+1Ti+1 (or TiCi–1Ti–1) variants are observed more frequently than TiCi+2Ti+2 (or TiCi–2Ti–2) variants. Moreover, the number of tertiary twin lamellae increases with the applied compressive strain.
Spherules from the Cretaceous/Tertiary boundary clay at Gubbio, Italy: the problem of outcrop contamination
Montanari, A.
Surficial outcrop contamination has occurred in some well-known stratigraphic sections of carbonate rocks in the northern Apennines. A critical case involves several contaminated clay partings, including the Cretaceous/Tertiary boundary clay in the classic Bottaccione section near Gubbio, Italy. These clay layers contain shiny spherules which, in several recent studies, have been said to consist of volcanic glass and have been used to support the hypothesis that the terminal Cretaceous mass extinction was caused by widespread volcanism. Laboratory tests, however, indicate that these shiny spherules are made of HF-insoluble and combustible material and are therefore of recent biological origin. These objects were introduced into the Cretaceous/Tertiary boundary clay and other clay layers from the surrounding soil along with abundant detrital contaminants derived from erosion of the middle Miocene flysch exposed at the head of the Bottaccione Gorge. They are completely different from the altered and flattened microtektitelike spheroids that are found only in the iridium-rich Cretaceous/Tertiary boundary clay and that provide strong evidence for a large impact.
Phase 2 Methyl Iodide Deep-Bed Adsorption Tests
Soelberg, Nick; Watson, Tony
Nuclear fission produces fission products (FPs) and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the second phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during the second half of Fiscal Year (FY) 2014. Test results continue to show that methyl iodide adsorption using AgZ can achieve total iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) above 1,000, until breakthrough occurred. However, mass transfer zone depths are deeper for methyl iodide adsorption compared to diatomic iodine (I2) adsorption. Methyl iodide DFs for the Ag Aerogel test adsorption efficiencies were less than 1,000, and the methyl iodide mass transfer zone depth exceeded 8 inches. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption under various conditions specified in the methyl iodide test plan, and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.
Gasoline and Diesel Fuel Update (EIA)
ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), and other aliphatic alcohols and ethers intended for motor gasoline blending...
Gasoline and Diesel Fuel Update (EIA)
ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), and other aliphatic alcohols and ethers intended for motor gasoline blending...
Distributions of methyl group rotational barriers in polycrystalline organic solids
Beckmann, Peter A. E-mail: firstname.lastname@example.com; Conn, Kathleen G.; Division of Education and Human Services, Neumann University, One Neumann Drive, Aston, Pennsylvania 19014-1298 ; Mallory, Clelia W.; Department of Chemistry, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899 ; Mallory, Frank B.; Rheingold, Arnold L.; Rotkina, Lolita; Wang, Xianlong E-mail: email@example.com
We bring together solid state {sup 1}H spin-lattice relaxation rate measurements, scanning electron microscopy, single crystal X-ray diffraction, and electronic structure calculations for two methyl substituted organic compounds to investigate methyl group (CH{sub 3}) rotational dynamics in the solid state. Methyl group rotational barrier heights are computed using electronic structure calculations, both in isolated molecules and in molecular clusters mimicking a perfect single crystal environment. The calculations are performed on suitable clusters built from the X-ray diffraction studies. These calculations allow for an estimate of the intramolecular and the intermolecular contributions to the barrier heights. The {sup 1}H relaxation measurements, on the other hand, are performed with polycrystalline samples which have been investigated with scanning electron microscopy. The {sup 1}H relaxation measurements are best fitted with a distribution of activation energies for methyl group rotation and we propose, based on the scanning electron microscopy images, that this distribution arises from molecules near crystallite surfaces or near other crystal imperfections (vacancies, dislocations, etc.). An activation energy characterizing this distribution is compared with a barrier height determined from the electronic structure calculations and a consistent model for methyl group rotation is developed. The compounds are 1,6-dimethylphenanthrene and 1,8-dimethylphenanthrene and the methyl group barriers being discussed and compared are in the 2�12 kJ?mol{sup ?1} range.
Rape oil methyl ester (RME) and used cooking oil methyl ester (UOME) as alternative fuels
Hohl, G.H.
The author presents a review about the fleet tests carried out by the Austrian Armed Forces concerning the practical application of a vegetable oil, i.e Rape Oil Methyl Ester (RME) and Used Cooking Oil Methyl Ester (UOME) as alternative fuels for vehicles under military conditions, and reviews other research results carried out in Austria. As a result of over-production in Western European agriculture, the increase in crop yields has led to tremendous surpluses. Alternative agricultural products have been sought. One alternative can be seen in biological fuel production for tractors, whereby the farmer is able to produce his own fuel supply as was the case when he previously provided self-made feed for his horses. For the market introduction different activities were necessary. A considerable number of institutes and organizations including the Austrian Armed Forces have investigated, tested and developed these alternative fuels. The increasing disposal problems of used cooking oil have initiated considerations for its use. The recycling of this otherwise waste product, and its preparation for use as an alternative fuel to diesel oil, seems to be most promising.
Phytoremediation of ionic and methyl mercury pollution
Meagher, R.B.
'The long-term objective of the research is to manipulate single-gene traits into plants, enabling them to process heavy metals and remediate heavy-metal pollution by resistance, sequestration, removal, and management of these contaminants. The authors are focused on mercury pollution as a case study of this plant genetic engineering approach. The working hypothesis behind this proposal was that transgenic plants expressing both the bacterial organo mercury lyase (merB) and the mercuric ion reductase gene (merA) will: (A) remove the mercury from polluted sites and (B) prevent methyl mercury from entering the food chain. The results from the research are so positive that the technology will undoubtedly be applied in the very near future to cleaning large mercury contaminates sites. Many such sites were not remediable previously due to the excessive costs and the negative environmental impact of conventional mechanical-chemical technologies. At the time this grant was awarded 20 months ago, the authors had successfully engineered a small model plant, Arabidopsis thaliana, to use a highly modified bacterial mercuric ion reductase gene, merA9, to detoxify ionic mercury (Hg(II)), reducing it to much less toxic and volatile metallic Hg(0) (Rugh et al., 1996). Seeds from these plants germinate, grow, and set seed at normal growth rates on levels of Hg(II) that are lethal to normal plants. In assays on transgenic seedlings suspended in a solution of Hg(II), 10 ng of Hg(0) was evolved per min per mg wet weight of plant tissue. At that time, the authors had no information on expression of merA in any other plant species, nor had the authors tested merB in any plant. However, the results were so startlingly positive and well received that they clearly presaged a paradigm shift in the field of environmental remediation.'
Properties of some ionic liquids based on1-methyl-3-octylimidazolium and 4-methyl-N-butylpyridinium cations.
Papaiconomou, Nicolas; Yakelis, Neal; Salminen, Justin; Bergman,Robert; Prausnitz, John M.
Syntheses are reported for ionic liquids containing 1-methyl-3octylimidazolium and 4-methyl-N-butylpyridinium cations, and trifluoromethansulfonate, dicyanamide, bis(trifluoromethylsulfonyl)imide, and nonafluorobutanesulfonate anions. Densities, melting points and glass transition points, solubility in water as well as polarities have been measured. Ionic liquids based on pyridinium cations exhibit higher melting points, lower solubility in water, and higher polarity than those based on imidazolium cations.
Anastomosing grabens, low-angle faults, and Tertiary thrust( ) faults, western Markagunt Plateau, southwestern Utah
Maldonado, F.; Sable, E.G. )
A structurally complex terrane composed of grabens and horsts, low-angle faults, Tertiary thrust( ) faults, gravity-slide blocks, and debris deposits has been mapped along the western Markagunt Plateau, east of Parowan and Summit, southwestern Utah. This terrane, structurally situated within the transition between the Basin and Range and Colorado Plateau provinces, contains Tertiary volcanic and sedimentary and Cretaceous sedimentary rocks. The structures are mostly Miocene to Oligocene but some are Pleistocene. The oldest structure is the Red Hills low-angle shear zone, interpreted as a shallow structure that decoupled an upper plate composed of a Miocene-Oligocene volcanic ash-flow tuff and volcaniclastic succession from a lower plate of Tertiary sedimentary rocks. The period of deformation on the shear zone is bracketed from field relationships between 22.5 and 20 Ma. The graben-horst system trends northeast and formed after about 20 Ma (and probably much later) based on displacement of dated dikes and a laccolith. The central part of the system contains many grabens that merge toward its southerly end to become a single graben. Within these grabens, (1) older structures are preserved, (2) debris eroded from horst walls forms lobe-shaped deposits, (3) Pleistocene basaltic cinder cones have localized along graben-bounding faults, and (4) rock units are locally folded suggesting some component of lateral translation along graben-bounding faults. Megabreccia deposits and landslide debris are common. Megabreccia deposits are interpreted as gravity-slide blocks of Miocene-Oligocene( ) age resulting from formation of the Red Hills shear zone, although some may be related to volcanism, and still others to later deformation. The debris deposits are landslides of Pleistocene-Pliocene( ) age possibly caused by continued uplift of the Markagunt Plateau.
Evidence for temperate conditions along the Antarctic peninsula during the Early Tertiary
Zinsmeister, W.J.
Several investigators based on deep sea glacial marine sediments from the southern oceans and volcanic sequences in West Antarctica have suggested extreme glacial conditions existed around Antarctica during the early Tertiary. Their data suggest ice sheets with ice shelves greater than those today were present on Antarctica by the late Eocene. If these data are correct, conditions during the Eocene along the Peninsula were similar to those that exist today. Late Eocene faunas and floras from Seymour Island indicate that conditions along the Peninsula were temperature. No paleontologic or geologic evidence have been obtained from Seymour Island (64/degree/18'S) to support the existence of glacial conditions along the northern part of the Peninsula during the early Tertiary. The presence of large quantities of fossil wood and plant debris in the upper Eocene sediments on Seymour Island indicates the presence of dense forests on the Peninsula during the Eocene. The discovery of marsupial and land birds remains on Seymour Island also indicate the presence of abundant terrestrial life on the Peninsula. The occurrence of an abundant marine life on Seymour Island supports the existence of temperate conditions along the Peninsula. Similarities of the Eocene faunas and floras with present day biotas from Tasmania, New Zealand and southern South America indicate that conditions along the Antarctic Peninsula during the late Eocene were comparable to present day mid latitudes of the southern hemisphere.
Nested methylation-specific polymerase chain reaction cancer detection method
Belinsky, Steven A.; Palmisano, William A.
A molecular marker-based method for monitoring and detecting cancer in humans. Aberrant methylation of gene promoters is a marker for cancer risk in humans. A two-stage, or "nested" polymerase chain reaction method is disclosed for detecting methylated DNA sequences at sufficiently high levels of sensitivity to permit cancer screening in biological fluid samples, such as sputum, obtained non-invasively. The method is for detecting the aberrant methylation of the p16 gene, O 6-methylguanine-DNA methyltransferase gene, Death-associated protein kinase gene, RAS-associated family 1 gene, or other gene promoters. The method offers a potentially powerful approach to population-based screening for the detection of lung and other cancers.
Geometric and Electronic Structures of the Ni(I) and Methyl-Ni(III)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Intermediates of Methyl-Coenzyme M Reductase 9 Geometric and Electronic Structures of the Ni(I) and Methyl-Ni(III) Intermediates of Methyl-Coenzyme M Reductase Methyl-coenzyme M reductase (MCR) from methanogenic archaea catalyzes the terminal step in biological methane synthesis. Using coenzyme B (CoBSH) as the two-electron donor, MCR reduces methyl-coenzyme M (methyl-SCoM) to form methane and the heterodisulfide product, CoBS-SCoM. MCR contains an essential redox active nickel tetrapyrrolic
Methods for detection of methyl-CpG dinucleotides
Dunn, John J
The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.
Methods for detection of methyl-CpG dinucleotides
Dunn, John J.
The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.
Methods for detection of methyl-CpG dinucleotides
Dunn, John J.
The invention provides methods for enriching methyl-CpG sequences from a DNA sample. The method makes use of conversion of cytosine residues to uracil under conditions in which methyl-cytosine residues are preserved. Additional methods of the invention enable to preservation of the context of me-CpG dinucleotides. The invention also provides a recombinant, full length and substantially pure McrA protein (rMcrA) for binding and isolation of DNA fragments containing the sequence 5'-C.sup.MeCpGG-3'. Methods for making and using the rMcrA protein, and derivatives thereof are provided.
Low Temperature Autoignition of C8H16O2 Ethyl and Methyl Esters...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Temperature Autoignition of C8H16O2 Ethyl and Methyl Esters in a Motored Engine Low Temperature Autoignition of C8H16O2 Ethyl and Methyl Esters in a Motored Engine qThe alkyl chain ...
Infant sex-specific placental cadmium and DNA methylation associations
Mohanty, April F.; Farin, Fred M.; Bammler, Theo K.; MacDonald, James W.; Afsharinejad, Zahra; Burbacher, Thomas M.; Siscovick, David S.; and others
Background: Recent evidence suggests that maternal cadmium (Cd) burden and fetal growth associations may vary by fetal sex. However, mechanisms contributing to these differences are unknown. Objectives: Among 24 maternal-infant pairs, we investigated infant sex-specific associations between placental Cd and placental genome-wide DNA methylation. Methods: We used ANOVA models to examine sex-stratified associations of placental Cd (dichotomized into high/low Cd using sex-specific Cd median cutoffs) with DNA methylation at each cytosine-phosphate-guanine site or region. Statistical significance was defined using a false discovery rate cutoff (<0.10). Results: Medians of placental Cd among females and males were 5 and 2 ng/g, respectively. Among females, three sites (near ADP-ribosylation factor-like 9 (ARL9), siah E3 ubiquitin protein ligase family member 3 (SIAH3), and heparin sulfate (glucosamine) 3-O-sulfotransferase 4 (HS3ST4) and one region on chromosome 7 (including carnitine O-octanoyltransferase (CROT) and TP5S target 1 (TP53TG1)) were hypomethylated in high Cd placentas. Among males, high placental Cd was associated with methylation of three sites, two (hypomethylated) near MDS1 and EVI1 complex locus (MECOM) and one (hypermethylated) near spalt-like transcription factor 1 (SALL1), and two regions (both hypomethylated, one on chromosome 3 including MECOM and another on chromosome 8 including rho guanine nucleotide exchange factor (GEF) 10 (ARHGEF10). Differentially methylated sites were at or close to transcription start sites of genes involved in cell damage response (SIAH3, HS3ST4, TP53TG1) in females and cell differentiation, angiogenesis and organ development (MECOM, SALL1) in males. Conclusions: Our preliminary study supports infant sex-specific placental Cd-DNA methylation associations, possibly accounting for previously reported differences in Cd-fetal growth associations across fetal sex. Larger studies are needed to replicate and extend these
Phase 1 Methyl Iodide Deep-Bed Adsorption Tests
Nick Soelberg; Tony Watson
Nuclear fission results in the production of fission products (FPs) and activation products including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent [Jubin 2012b]. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the first phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during Fiscal Year (FY) 2013 and early FY-2014. Testing has been performed to address questions posed in the test plan, and followed the testing outline in the test plan. Tests established detection limits, developed procedures for sample analysis with minimal analytical interferences, and confirmed earlier results that show that the methyl iodide reacts when in contact with the AgZ sorbent, and not significantly in the gas flow upstream of the sorbent. The reaction(s) enable separation of the iodine from the organic moiety, so that the iodine can chemisorb onto the sorbent. The organic moiety can form other compounds, some of which are organic compounds that are detected and can be tentatively identified using GC-FID and GCMS. Test results also show that other gas constituents (NOx and/or H2O) can affect the methyl iodide reactions. With NOx and H2O present in the gas stream, the majority of uncaptured iodine exiting iodine-laden sorbent beds is in the form of I2 or HI, species that
Chemically induced Parkinson's disease: intermediates in the oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to the 1-methyl-4-phenyl-pyridinium ion
Chacon, J.N.; Chedekel, M.R.; Land, E.J.; Truscott, T.G.
Various unstable intermediate oxidation states have been postulated in the metabolic activation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to the 1-methyl-4-phenyl pyridinium ion. We now report the first direct observation of these free radical intermediates by pulse radiolysis and flash photolysis. Studies are described of various reactions of such species, in particular with dopamine whose autoxidation to dopamine quinone is reported to be potentiated by 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine.
Reports and Publications (EIA)
This paper analyzes the supply impacts of removing methyl tertiary butyl ether (MTBE) from gasoline.
Tropospheric oxidation mechanism of dimethyl ether and methyl formate
Good, D.A.; Francisco, J.S.
The oxidation mechanism of dimethyl ether is investigated using ab initio methods. The structure and energetics of reactants, products, and transition structures are determined for all pathways involved in the oxidation mechanism. The detailed pathways leading to the experimentally observed products of dimethyl ether oxidation are presented. The energetics of over 50 species and transition structures involved in the oxidation process are calculated with G2 and G2(MP2) energies. The principal pathway following the initial attack of dimethyl ether (CH{sub 3}OCH{sub 3}) by the OH radical is the formation of the methoxymethyl radical (CH{sub 2}OCH{sub 3}). Oxidation steps lead to the formation of methyl formate, which is consistent with the experimentally observed products. Oxidation pathways of methyl formate are also considered.
Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi; Samuel S. Tam
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (January-March/99), in-situ formaldehyde generation and condensation with methyl propionate were tested over various catalysts and reaction conditions. The patent application is in preparation and the results are retained for future reports.
Synthesis of 6-Methyl-9-n-propyldibenzothiophene-4-ol
Not Available
The material presented here has been described to some extent in Status Reports 12, 13, and 14 and covers the progress toward the synthesis of the modified target molecules 9-isopropyl-4-methoxy-6-methyldibenzothiophene (13) and 9-isopropyl-6-methyldibenzothiophene-4-ol (14). It is divided into three parts: (a) Dehydrogenation experiments On tetrahydrodibenzothiophene 12. (b) methoxyl methyl cleavage of 13 to 14 using boron tribromide. (c) isolation and purification of methoxydibenzothiophene 13.
"Seeing" Mercury Methylation in Progress
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Mercury in the environment can easily reach toxic levels. In a process called methylation, Hg is transformed into a form that can be accumulated in the muscle and fatty tissue of fish. Accumulated levels of methylmercury become higher as the fish grow, and levels are magnified up the food web as larger fish eat smaller fish, a process called biomagnification. As a result, mercury concentrations in fish can be millions of times higher than in surrounding waters [1]. Fish advisories have been set
FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report
Soelberg, Nicholas Ray; Watson, Tony Leroy
Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO3 and increased NO2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO2, very low H2O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.
Cytotoxic and DNA-damaging effects of methyl tert-butyl ether and its metabolites on HL-60 cells in vitro
Tang, G.H.; Shen, Y.; Shen, H.M.
Methyl tert-butyl ether (MTBE) is a widely used oxygenate in unleaded gasoline; however, few studies have been conducted on the toxicity of this compound. This study evaluates the cytotoxic and DNA-damaging effects of MTBE and its metabolites in a human haemopoietic cell line, HL-60. The metabolites of MTBE studied include tertiary butyl alcohol (TBA), {alpha}-hydroxyisobutyric acid (HIBA), and formaldehyde. Comet assay is used to assess DNA damage, and the cytotoxicity is investigated by lactate dehydrogenease (LDH) release. The results show no significant cytotoxic effects of MTBE, TBA, and HIBA over a concentration ranging from 1 to 30 mM. Formaldehyde, in contrast, causes a substantial LDH release at a concentration of 5 {mu}M. Hydrogen peroxide, a known oxidative agent, at concentrations ranging from 10 to 100 {mu}M, produces a significant dose-related increase in DNA damage, whereas a much higher concentration of MTBE (1 to 30 mM) is required to produce a similar observation. The genotoxic effects of TBA and HIBA appear to be identical to that of MTBE. Conversely, DNA damage is observed for formaldehyde at a relatively low concentration range (5 to 100 {mu}M). These findings suggest that MTBE and its metabolites, except formaldehyde, have relatively low cytotoxic and genotoxic effects. 16 refs., 4 figs.
Iridium profile for 10 million years across the Cretaceous-Tertiary boundary at Gubbio (Italy)
Alvarez, W.; Montanari, A. ); Asaro, F. )
The iridium anomaly at the Cretaceous-Tertiary (KT) boundary was discovered in the pelagic limestone sequence at Gubbio on the basis of 12 samples analyzed by neutron activation analysis (NAA) and was interpreted as indicating impact of a large extraterrestrial object at exactly the time of the KT mass extinction. Continuing controversy over the shape of the Ir profile at the Gubbio KT boundary and its interpretation called for a more detailed follow-up study. Analysis of a 57-meter-thick, 10-million-year-old part of the Gubbio sequence using improved NAA techniques revealed that there is only one Ir anomaly at the KT boundary, but this anomaly shows an intricate fine structure, the origin of which cannot yet be entirely explained. The KT Ir anomaly peaks in a 1-centimeter-thick clay layer, where the average Ir concentration is 3,000 parts per trillion (ppt); this peak is flanked by tails with Ir concentrations of 20 to 80 ppt that rise above a background of 12 to 13 ppt. The fine structure of the tails is probably due in part to lateral reworking, diffusion, burrowing, and perhaps Milankovitch cyclicity.
Synsedimentary tectonics in Late Cretaceous-Early Tertiary pelagic basin of northern Apennines, Italy
Montanari, A.; Chan, L.S.; Alvarez, W.
The sequence of Upper Cretaceous-Lower Tertiary pelagic limestones in the Umbria-Marches Apennines of Italy have recorded, with remarkable continuity, the geologic history of an epeiric sea on the eastern continental margin of the Ligurian Ocean during a time of widespread tectonism in the western Tethys domain. Sedimentary facies and paleocurrent analyses indicate that intrabasinal depocenters and structural highs have formed in response to extensional tectonic movements which started to affect the central part of the paleobasin in the early Turonian. The topography of the paleobasin was probably controlled by a complex pattern of buried fault blocks formed during the passive margin phase of the western Tethys and then reactivated in the Turonian after a prolonged time (Aptian to Cenomanian) of tectonic quiescence. Calcareous turbidites essentially made of remobilized pelagic mud were generated on the newly formed intrabasinal slopes and deposited in the adjacent depocenters. Conspicuous sedimentary events such as maxima in turbiditic deposition and soft-sediment slumps in these intrabasinal depocenters are attributed to major syndepositional earthquakes of regional extent. A detailed event-stratigraphy based on these sedimentary features indicates that the level of syndepositional tectonic activity reached a peak in the late Maastrichtian-early Paleocene and rapidly diminished in the Eocene.
Methyl aryl ethers from coal liquids as gasoline extenders and octane improvers
Singerman, G.M.
A mixture of methyl aryl ethers derived from the phenols present in direct liquefaction coal liquids shows considerable promise as a gasoline blending agent and octane improver. The mixture of methyl aryl ethers was blended at five volume percent with a commercial, unleaded gasoline. The properties and performance of the blend in a variety of laboratory and automotive tests is reported. The tests show that the mixture of methyl aryl ethers improves gasoline octane without degrading other gasoline properties.
Vacuum ultraviolet and infrared spectra of condensed methyl acetate on cold astrochemical dust analogs
Sivaraman, B.; Nair, B. G.; Mason, N. J.; Lo, J.-I.; Cheng, B.-M.; Kundu, S.; Davis, D.; Prabhudesai, V.; Krishnakumar, E.; Raja Sekhar, B. N.
Following the recent report of the first identification of methyl acetate (CH{sub 3}COOCH{sub 3}) in the interstellar medium (ISM), we have carried out vacuum ultraviolet (VUV) and infrared (IR) spectroscopy studies on methyl acetate from 10 K until sublimation in an ultrahigh vacuum chamber simulating astrochemical conditions. We present the first VUV and IR spectra of methyl acetate relevant to ISM conditions. Spectral signatures clearly showed molecular reorientation to have started in the ice by annealing the amorphous ice formed at 10 K. An irreversible phase change from amorphous to crystalline methyl acetate ice was found to occur between 110 K and 120 K.
Exploring the roles of DNA methylation in the metal-reducing bacterium Shewanella oneidensis MR-1
Bendall, Matthew L.; Luong, Khai; Wetmore, Kelly M.; Blow, Matthew; Korlach, Jonas; Deutschbauer, Adam; Malmstrom, Rex
We performed whole genome analyses of DNA methylation in Shewanella 17 oneidensis MR-1 to examine its possible role in regulating gene expression and 18 other cellular processes. Single-Molecule Real Time (SMRT) sequencing 19 revealed extensive methylation of adenine (N6mA) throughout the 20 genome. These methylated bases were located in five sequence motifs, 21 including three novel targets for Type I restriction/modification enzymes. The 22 sequence motifs targeted by putative methyltranferases were determined via 23 SMRT sequencing of gene knockout mutants. In addition, we found S. 24 oneidensis MR-1 cultures grown under various culture conditions displayed 25 different DNA methylation patterns. However, the small number of differentially 26 methylated sites could not be directly linked to the much larger number of 27 differentially expressed genes in these conditions, suggesting DNA methylation is 28 not a major regulator of gene expression in S. oneidensis MR-1. The enrichment 29 of methylated GATC motifs in the origin of replication indicate DNA methylation 30 may regulate genome replication in a manner similar to that seen in Escherichia 31 coli. Furthermore, comparative analyses suggest that many 32 Gammaproteobacteria, including all members of the Shewanellaceae family, may 33 also utilize DNA methylation to regulate genome replication.
Phase 1 Methyl Iodide Deep-Bed Adsorption Tests (Technical Report...
Office of Scientific and Technical Information (OSTI)
Tests established detection limits, developed procedures for sample analysis with minimal analytical interferences, and confirmed earlier results that show that the methyl iodide ...
Evaluation of alternate routes for the synthesis of methyl methacrylate
Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.
The use of coal-derived syngas to produce high value chemicals is an important means of upgrading this resource. One example of a chemical that can be produced from coal-derived syngas is methyl methacrylate (MMA). Poly-methyl methacrylate is widely used in coatings and in various industrial molded products. The most widely practiced commercial technology for the synthesis of MMA is the acetone cyanohydrin (ACH) process. This process requires handling of large quantities of toxic hydrogen cyanide and generates one mole of ammonium bisulfate waste per mole of MMA. This bisulfate must either be regenerated or discarded, either of which substantially increases the cost. The ACH technology is thus environmentally and economically untenable for any new MMA plant expansions that would be needed to meet increasing demand. The RTI-Eastman-Bechtel research team is developing an alternative, environmentally benign route to MMA consisting of three steps; (step 1) synthesis of a propionate from ethylene, carbon monoxide, and steam, (step 2) condensation of this propionate with formaldehyde, and (step 3) esterification of resulting methacrylic acid with methanol to form MMA. This paper describes the preliminary economics of the overall process compared to other emerging processes, and focuses on step 2, including long term testing of catalysts for the condensation of propionic acid with formaldehyde to form MAA.
Use of Treated Municipal Wastewater as Power Plant Cooling System Makeup Water: Tertiary Treatment versus Expanded Chemical Regimen for Recirculating Water Quality Management
David Dzombak; Radisav Vidic; Amy Landis
Treated municipal wastewater is a common, widely available alternative source of cooling water for thermoelectric power plants across the U.S. However, the biodegradable organic matter, ammonia-nitrogen, carbonate and phosphates in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, respectively. The overall objective of this study was to evaluate the benefits and life cycle costs of implementing tertiary treatment of secondary treated municipal wastewater prior to use in recirculating cooling systems. The study comprised bench- and pilot-scale experimental studies with three different tertiary treated municipal wastewaters, and life cycle costing and environmental analyses of various tertiary treatment schemes. Sustainability factors and metrics for reuse of treated wastewater in power plant cooling systems were also evaluated. The three tertiary treated wastewaters studied were: secondary treated municipal wastewater subjected to acid addition for pH control (MWW_pH); secondary treated municipal wastewater subjected to nitrification and sand filtration (MWW_NF); and secondary treated municipal wastewater subjected nitrification, sand filtration, and GAC adsorption (MWW_NFG). Tertiary treatment was determined to be essential to achieve appropriate corrosion, scaling, and biofouling control for use of secondary treated municipal wastewater in power plant cooling systems. The ability to control scaling, in particular, was found to be significantly enhanced with tertiary treated wastewater compared to secondary treated wastewater. MWW_pH treated water (adjustment to pH 7.8) was effective in reducing scale formation, but increased corrosion and the amount of biocide required to achieve appropriate biofouling control. Corrosion could be adequately controlled with tolytriazole addition (4-5 ppm TTA), however, which was the case for all of the tertiary treated waters. For MWW_NF treated water, the removal of ammonia by
Unexpected methyl migrations of ethanol dimer under synchrotron VUV radiation
Xiao, Weizhan; Hu, Yongjun E-mail: firstname.lastname@example.com; Li, Weixing; Guan, Jiwen; Liu, Fuyi; Shan, Xiaobin; Sheng, Liusi E-mail: email@example.com
While methyl transfer is well known to occur in the enzyme- and metal-catalyzed reactions, the methyl transfer in the metal-free organic molecules induced by the photon ionization has been less concerned. Herein, vacuum ultraviolet single photon ionization and dissociation of ethanol dimer are investigated with synchrotron radiation photoionization mass spectroscopy and theoretical methods. Besides the protonated clusters cation (C{sub 2}H{sub 5}OH) ⋅ H{sup +} (m/z = 47) and the β-carbon-carbon bond cleavage fragment CH{sub 2}O ⋅ (C{sub 2}H{sub 5}OH)H{sup +} (m/z = 77), the measured mass spectra revealed that a new fragment (C{sub 2}H{sub 5}OH) ⋅ (CH{sub 3}){sup +} (m/z = 61) appeared at the photon energy of 12.1 and 15.0 eV, where the neutral dimer could be vertically ionized to higher ionic state. Thereafter, the generated carbonium ions are followed by a Wagner-Meerwein rearrangement and then dissociate to produce this new fragment, which is considered to generate after surmounting a few barriers including intra- and inter-molecular methyl migrations by the aid of theoretical calculations. The appearance energy of this new fragment is measured as 11.55 ± 0.05 eV by scanning photoionization efficiency curve. While the signal intensity of fragment m/z = 61 starts to increase, the fragments m/z = 47 and 77 tend to slowly incline around 11.55 eV photon energy. This suggests that the additional fragment channels other than (C{sub 2}H{sub 5}OH) ⋅ H{sup +} and CH{sub 2}O ⋅ (C{sub 2}H{sub 5}OH)H{sup +} have also been opened, which consume some dimer cations. The present report provides a clear description of the photoionization and dissociation processes of the ethanol dimer in the range of the photon energy 12-15 eV.
Methyl-CpG island-associated genome signature tags
Dunn, John J
Disclosed is a method for analyzing the organismic complexity of a sample through analysis of the nucleic acid in the sample. In the disclosed method, through a series of steps, including digestion with a type II restriction enzyme, ligation of capture adapters and linkers and digestion with a type IIS restriction enzyme, genome signature tags are produced. The sequences of a statistically significant number of the signature tags are determined and the sequences are used to identify and quantify the organisms in the sample. Various embodiments of the invention described herein include methods for using single point genome signature tags to analyze the related families present in a sample, methods for analyzing sequences associated with hyper- and hypo-methylated CpG islands, methods for visualizing organismic complexity change in a sampling location over time and methods for generating the genome signature tag profile of a sample of fragmented DNA.
High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes
Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M
Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.
Global prevalence and distribution of genes and microorganisms involved in mercury methylation
Podar, Mircea; Gilmour, C C; Brandt, Craig C; Bullock, Allyson L; Brown, Steven D; Crable, Bryan R; Palumbo, Anthony Vito; Somenahally, Anil C; Elias, Dwayne A
Mercury methylation produces the neurotoxic, highly bioaccumulative methylmercury (MeHg). Recent identification of the methylation genes (hgcAB) provides the foundation for broadly evaluating microbial Hg-methylation potential in nature without making explicit rate measurements. We queried hgcAB diversity and distribution in all available microbial metagenomes, encompassing most environments. The genes were found in nearly all anaerobic, but not in aerobic, environments including oxygenated layers of the open ocean. Critically, hgcAB was effectively absent in ~1500 human microbiomes, suggesting a low risk of endogenous MeHg production. New potential methylation habitats were identified, including invertebrate guts, thawing permafrost, coastal dead zones , soils, sediments, and extreme environments, suggesting multiple routes for MeHg entry into food webs. Several new taxonomic groups potentially capable of Hg-methylation emerged, including lineages having no cultured representatives. We begin to address long-standing evolutionary questions about Hg-methylation and ancient carbon fixation mechanisms while generating a new global view of Hg-methylation potential.
Global prevalence and distribution of genes and microorganisms involved in mercury methylation
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Podar, Mircea; Gilmour, C. C.; Brandt, Craig C.; Soren, Allyson; Brown, Steven D.; Crable, Bryan R.; Palumbo, Anthony Vito; Somenahally, Anil C.; Elias, Dwayne A.
Mercury methylation produces the neurotoxic, highly bioaccumulative methylmercury (MeHg). Recent identification of the methylation genes (hgcAB) provides the foundation for broadly evaluating microbial Hg-methylation potential in nature without making explicit rate measurements. We first queried hgcAB diversity and distribution in all available microbial metagenomes, encompassing most environments. The genes were found in nearly all anaerobic, but not in aerobic, environments including oxygenated layers of the open ocean. Critically, hgcAB was effectively absent in ~1500 human microbiomes, suggesting a low risk of endogenous MeHg production. New potential methylation habitats were identified, including invertebrate guts, thawing permafrost, coastal dead zones, soils, sediments,more » and extreme environments, suggesting multiple routes for MeHg entry into food webs. Several new taxonomic groups potentially capable of Hg-methylation emerged, including lineages having no cultured representatives. We then begin to address long-standing evolutionary questions about Hg-methylation and ancient carbon fixation mechanisms while generating a new global view of Hg-methylation potential.« less
Global prevalence and distribution of genes and microorganisms involved in mercury methylation
Podar, Mircea; Gilmour, C. C.; Brandt, Craig C.; Soren, Allyson; Brown, Steven D.; Crable, Bryan R.; Palumbo, Anthony Vito; Somenahally, Anil C.; Elias, Dwayne A.
Mercury methylation produces the neurotoxic, highly bioaccumulative methylmercury (MeHg). Recent identification of the methylation genes (hgcAB) provides the foundation for broadly evaluating microbial Hg-methylation potential in nature without making explicit rate measurements. We first queried hgcAB diversity and distribution in all available microbial metagenomes, encompassing most environments. The genes were found in nearly all anaerobic, but not in aerobic, environments including oxygenated layers of the open ocean. Critically, hgcAB was effectively absent in ~1500 human microbiomes, suggesting a low risk of endogenous MeHg production. New potential methylation habitats were identified, including invertebrate guts, thawing permafrost, coastal dead zones, soils, sediments, and extreme environments, suggesting multiple routes for MeHg entry into food webs. Several new taxonomic groups potentially capable of Hg-methylation emerged, including lineages having no cultured representatives. We then begin to address long-standing evolutionary questions about Hg-methylation and ancient carbon fixation mechanisms while generating a new global view of Hg-methylation potential.
Factors affecting the retention of methyl iodide by iodide-impregnated carbon
Hyder, M.L.; Malstrom, R.A.
Iodide-impregnated activated carbon that had been in use for up to 30 months was studied to characterize those factors that affect its interaction with and retention of methyl iodide. Humidity and competing organic sorbents were observed to decrease the residence time of the methyl iodide on the carbon bed. Additionally, changes in the effective surface area and the loss of iodide from the surface are both important in determining the effectiveness of the carbon for retaining radioactive iodine from methyl iodide. A simple model incorporating both factors gave a fairly good fit to the experimental data.
Factors affecting the retention of methyl iodide by iodide-impregnated carbon
Hyder, M.L.; Malstrom, R.A.
Iodide-impregnated activated carbon that had been in use for up to 30 months was studied to characterize those factors that affect its interaction with and retention of methyl iodide. Humidity and competing organic sorbents were observed to decrease the residence time of the methyl iodide on the carbon bed. Additionally, changes in the effective surface area and the loss of iodide from the surface are both important in determining the effectiveness of the carbon for retaining radioactive iodine from methyl iodide. A simple model incorporating both factors gave a fairly good fit to the experimental data.
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200°C to 500°C. The conversion of DME first increases with temperature reaching an maximum at 400°C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350�
Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. During the April-June quarter(04-06/99) the first in-situ formaldehyde generation from DME and condensation with methyl propionate is demonstrated and the results are summarized. The supported niobium catalyst shows better condensation activity, but supported tungsten catalyst has higher formaldehyde selectivity. The project team has also completed a 200-hour long term test of PA-HCHO condensation over 30% Nb{sub 2}O{sub 5}/SiO{sub 2}. Three activity cycles and two regeneration cycles were carried out. 30% Nb{sub 2}O{sub 5}/SiO{sub 2} showed similar MAA yields as 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. However, the deactivation appears to be slower with 30% Nb{sub 2}O{sub 5}/SiO{sub 2} than 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. An detailed economic analysis of PA-HCHO condensation process for a 250 million lb/yr MMA plant is currently studied by Bechtel. Using the Amoco data-based azeotropic distillation model as the basis, an ASPEN flow sheet model was constructed to simulate the formaldehyde and propionic acid condensation processing section based on RTI's design data. The RTI MAA effluent azeotropic distillation column was found to be much more difficult to converge. The presence of non-condensible gases along with the byproduct DEK (both of which were not presented in
Thermochemistry of C-O, (CO)-O, and (CO)-C bond breaking in fatty acid methyl esters
Osmont, Antoine; Yahyaoui, Mohammed; Catoire, Laurent; Goekalp, Iskender; Swihart, Mark T.
Density functional theory quantum chemical calculations corrected with empirical atomic increments have been used to examine C-O, (CO)-O, and (CO)-C bond scission enthalpies in gas-phase fatty acid methyl esters (FAMEs) present in biodiesel derived from rapeseed oil methyl ester and soybean oil methyl ester. Mechanistic information, currently not available elsewhere for these large species, is obtained based on thermochemical considerations and compared to thermochemical considerations reported for methyl butanoate, a small methyl ester sometimes used as a model for FAMEs. These results are compared to previously reported C-C and C-H bond scissions in these FAMEs, derived using this same protocol. (author)
Synthesis of Methyl Methacrylate from Coal-Derived Syngas
Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Makarand R. Gogate; Richard D. Colberg; Samuel S. Tam
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last month, RTI has finalized the design of a fixed-bed microreactor system for DME partial oxidation reactions. RTI incorporated some design changes to the feed blending system, so as to be able to blend varying proportions of DME and oxygen. RTI has also examined the flammability limits of DME-air mixtures. Since the lower flammability limit of DME in air is 3.6 volume percent, RTI will use a nominal feed composition of 1.6 percent in air, which is less than half the lower explosion limit for DME-air mixtures. This nominal feed composition is thus considered operationally safe, for DME partial oxidation reactions. RTI is also currently developing an analytical system for DME partial oxidation reaction system.
Novel syngas-based process for methyl methacrylate
Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Choi, G.N.; Tam, S.S.; Tischer, R.E.; Srivastava, R.D.
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel are developing a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Pittsburgh Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the research on propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis, which shows that Eastman`s propionate synthesis process is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-SI-P and Ta metal oxide catalysts for condensation reactions of propionates with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields, acid-base properties, in situ condensation in a high- temperature, high-pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory reactor operating data, a cost estimate is also being developed for the integrated process.
Optimized End-Stacking Provides Specificity of N-Methyl Mesoporphyrin...
Office of Scientific and Technical Information (OSTI)
Optimized End-Stacking Provides Specificity of N-Methyl Mesoporphyrin IX for Human Telomeric G-Quadruplex DNA Citation Details In-Document Search Title: Optimized End-Stacking ...
Review and reconnaissance of the hydrogeology of Tertiary sedimentary rocks in the vicinity of Frenchman Flat, Nevada Test Site
Prothro, L.B.; Drellack, S.L. Jr.
Work is currently underway within the Underground Test Area (UGTA) subproject of the US Department of Energy/Nevada Operations Office Environmental Restoration Program to develop corrective action plans in support of the overall corrective action strategy for the Nevada Test Site (NTS) as established in the Federal Facility Agreement and Consent Order (FFACO, 1996). A closure plan is currently being developed for Frenchman Flat, which has been identified in the FFACO as a Corrective Action Unit (CAU). Part of this effort requires that hydrogeologic data be compiled for inclusion in a CAU-specific hydrologic flow and transport model that will be used to predict contaminant boundaries. Hydrogeologic maps and cross sections are currently being prepared for use in the model to define the nature and extent of aquifers and confining units that might influence the flow of contaminated groundwater from underground nuclear tests conducted in Frenchman Flat. During this effort, it has been found that older Tertiary-age sediments might be hydrogeologically important in the Frenchman Flat model area. Although the character and extent of these units are poorly known, there is reason to believe that in some parts of Frenchman Flat they may lie between the regional Lower Carbonate Aquifer (LCA) and the younger Tertiary saturated alluvium and volcanic units in which several underground nuclear tests were conducted. It was not possible to quickly determine their extent, or ascertain whether or not these units might act as confining units or aquifers. The work described in this report was done to gain a better understanding of the hydrogeology of these rocks.
Renewed petroleum generation related to Tertiary intrusions and increased heat flow, western Permian basin, Texas and New Mexico
Barker, C.E.; Pawlewicz, M.J.
Higher paleogeothermal gradients, commencing in the Tertiary after maximum burial, have caused renewed petroleum generation in the western Permian basin. Evidence for this reheating is two distinct trends in the mean random vitrinite reflectance (R/sub m/) and depth data compiled from over 40 wells. One group, with a 0.7% R/sub m//km gradient, is from the western edge of the basin; the other, with a 0.5% R/sub m//km gradient, is from the central and eastern portions. Post-Mississippian tilting produced greater subsidence and a thicker, mostly uneroded sedimentary section in the eastern portion of the Permian basin. Continued tilting prior to the Cretaceous caused uplift and erosion that exposed the Upper Permian section in the western part. Potassium-argon ages of igneous intrusions along the western edge of the basin show they were emplaced about 35 Ma, followed by Miocene to Holocene basin-and-range-type block faulting and associated high heat flow. Isopach-reflectance contours confirm this renewed heating is post-tectonic - that is, it occurred after eastward tilting and erosion had reduced burial depth. Maximum temperatures computed from R/sub m/-depth relationships infer that paleogeothermal gradients exceeded 40/degrees/C/km (2.2/degrees/F/100 ft) in the Tertiary. This reheating thermally matured rocks as young as Guadalupian in the western Permian basin and apparently caused a second episode of petroleum generation. By this time, however, the potential reservoir rocks and evaporite seals had been deeply eroded, resulting in poor conditions for trapping the renewed pulse of petroleum.
Radio-methyl vorozole and methods for making and using the same
Kim, Sung Won; Biegon, Anat; Fowler, Joanna S.
Radiotracer vorozole compounds for in vivo and in vitro assaying, studying and imaging cytochrome P450 aromatase enzymes in humans, animals, and tissues and methods for making and using the same are provided. [N-radio-methyl] vorozole substantially separated from an N-3 radio-methyl isomer of vorozole is provided. Separation is accomplished through use of chromatography resins providing multiple mechanisms of selectivity.
Radio-methyl vorozole and methods for making and using the same
Kim, Sung Won; Biegon, Anat; Fowler, Joanna S.
Radiotracer vorozole compounds for in vivo and in vitro assaying, studying and imaging cytochrome P450 aromatase enzymes in humans, animals, and tissues and methods for making and using the same are provided. [N-radio-methyl] vorozole substantially separated from an N-3 radio-methyl isomer of vorozole is provided. Separation is accomplished through use of chromatography resins providing multiple mechanisms of selectivity.
Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ
Office of Scientific and Technical Information (OSTI)
Transesterification: Laboratory Analytical Procedure (LAP) (Technical Report) | SciTech Connect Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP) Citation Details In-Document Search Title: Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP) This procedure is based on a whole biomass transesterification of lipids to fatty acid
Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows
Seshadri, K; Lu, T; Herbinet, O; Humer, S; Niemann, U; Pitz, W J; Law, C K
Methyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using 'directed relation graph' method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.
Synthesis of Methyl Methacrylate From Coal-Derived Syngas
Ben W.-L. Jang; Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Richard D. Colberg; Samuel S. Tam
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(April-June, 1998), RTI has modified the reactor system including a new preheater and new temperature settings for the preheater. Continuous condensation of formaldehyde with propionic acid were carried out over 10% Nb O /SiO at 300°C without 2 5 2 interruption. Five activity and four regeneration cycles have been completed without plugging or material balance problems. The results show that 10% Nb O /SiO deactivates slowly with time 2 5 2 but can be regenerated, at least four times, to 100% of its original activity with 2% O in nitrogen 2 at 400°C. The cycles continue with consistent 90-95% of carbon balance. The reaction is scheduled to complete with 6 activity cycles and 5 regenerations. Used catalysts will be analyzed with TGA and XPS to determine bulk and surface coke content and coke properties. RTI will start the investigation of effects of propionic acid/formaldehyde ratio on reaction activity and product selectivity over 20% Nb O /SiO catalysts.
Vapor pressures of methyl tert-butyl ether, ethyl tert-butyl ether, isopropyl tert-butyl ether, tert-amyl methyl ether, and tert-amyl ethyl ether
Kraehenbuehl, M.A.; Gmehling, J. . Technische Chemie)
The vapor pressures of methyl tert-butyl ether, ethyl tert-butyl ether, isopropyl tert-butyl ether, tert-amyl methyl ether, and tert-amyl ethyl ether were measured by ebulliometry or the static method in the pressure ranges 14--102 and 3--835 kPa (methyl tert-butyl ether), respectively. The data were correlated using the Antoine and Wagner equations. The experimental data of methyl tert-butyl ether and ethyl tert-butyl ether were compared with data available in the literature.
Novel catalysts for the environmentally friendly synthesis of methyl methacrylate
Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.
The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodine-promoted Mo(CO){sub 6} catalyst at pressures (30--70 atm) and temperatures (150--200 C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO){sub 6}. This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO){sub 5}. This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals supported on an amorphous silica are found to be most effective. A 20% Nb/SiO{sub 2} catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 = mol of NH{sub 3}/g), with a high proportion of the acidity being weak (<350 C desorption of NH{sub 3}), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (July-September, 1998), the project team has completed the continuous condensation of formaldehyde with propionic acid over 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. Six activity and five regeneration cycles have been completed. The results show that 10% Nb{sub 2}O{sub 5}/SiO{sub 2} deactivates slowly with time but can be regenerated to its original activity with 2% O{sub 2} in nitrogen over night at 400 C. We have investigated the effects of regeneration, propionic acid/formaldehyde ratio (PA/HCHO = 4.5/1 to 1.5/1) and reaction temperature(280-300 C) on reaction activity and product selectivity over 20% Nb{sub 2}O{sub 5}/SiO{sub 2} catalysts. The regeneration effect on 20% Nb{sub 2}O{sub 5}/SiO{sub 2} is similar to the effect on 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. The regeneration can bring the deactivated catalyst to its original activity. However, the selectivity to MAA decreases with regeneration while the selectivity to DEK and CO{sub 2} increases. When PA/HCHO ratio is decreased from 4.5/1 to 2.25/1 then to 1.5/1 at 300 C the MAA yield decreases but the MAA selectivity first increases then decreases. Decreasing the reaction temperature from 300 C to 280 C decreases the MAA yield from 39.5% to 30.7% but increases the MAA selectivity from 73.7% to 82.2%. The
The use of nonmarine palynomorphs as correlation tools in rapidly deposited upper tertiary sediments of the Gulf of Mexico
Ravn, R.L. ); D'Ablaing, J.A. )
Rapidly deposited upper Tertiary sediments can pose significant correlation problems for the biostratigrapher using foraminifera or calcareous nannoplankton because the abundance of marine organisms commonly is greatly diluted. In contrast, such sediments often contain abundant pollen and spores. This palynological population was collected by the proto-Mississippi and perhaps other rivers from a huge hinterland source area probably comparable to that of the Mississippi drainage today. The sediment therefore reflects a general floral population over a large region and may be expected to record important fluctuations in constituent elements of the flora due to climatic changes over time. A secondary overprint of physical sorting also may influence the relative distributions of certain forms. Although not strongly useful as an age-dating tool (the vast majority of forms occurring in Miocene or younger strata represent parent plant types that still exist today), these palynomorph populations do show strong potential as tools for correlation based on quantitative analyses. Palynological [open quotes]logs[close quotes] can be produced using inexpensive standard spreadsheet software and various mathematical evaluation techniques. An example from the Pliocene of offshore Louisiana demonstrates that numerous potential correlation horizons can be defined in a relatively brief time interval in a section in which standard marine microfossils are of little use owing to their scarcity.
MTBE Production Economics (Released in the STEO April 2001)
Reports and Publications (EIA)
The purpose of this analysis is to evaluate the causes of methyl tertiary butyl ether (MTBE) price increases in 2000.
The role of DNA methylation in catechol-enhanced erythroid differentiation of K562 cells
Li, Xiao-Fei; Wu, Xiao-Rong; Xue, Ming; Wang, Yan; Wang, Jie; Li, Yang; Suriguga,; Zhang, Guang-Yao; Yi, Zong-Chun
Catechol is one of phenolic metabolites of benzene in vivo. Catechol is also widely used in pharmaceutical and chemical industries. In addition, fruits, vegetables and cigarette smoke also contain catechol. Our precious study showed that several benzene metabolites (phenol, hydroquinone, and 1,2,4-benzenetriol) inhibited erythroid differentiation of K562 cells. In present study, the effect of catechol on erythroid differentiation of K562 cells was investigated. Moreover, to address the role of DNA methylation in catechol-induced effect on erythroid differentiation in K562 cells, methylation levels of erythroid-specific genes were analyzed by Quantitative MassARRAY methylation analysis platform. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation in K562 cells in concentration- and time-dependent manners. The mRNA expression of erythroid specific genes, including ?-globin, ?-globin, ?-globin, erythroid 5-aminolevulinate synthase, erythroid porphobilinogen deaminase, and transcription factor GATA-1 genes, showed a significant concentration-dependent increase in catechol-treated K562 cells. The exposure to catechol caused a decrease in DNA methylation levels at a few CpG sites in some erythroid specific genes including ?-globin, ?-globin and erythroid porphobilinogen deaminase genes. These results indicated that catechol improved erythroid differentiation potency of K562 cells at least partly via up-regulating transcription of some erythroid related genes, and suggested that inhibition of DNA methylation might be involved in up-regulated expression of some erythroid related genes. -- Highlights: ? Catechol enhanced hemin-induced hemoglobin accumulation. ? Exposure to catechol resulted in up-regulated expression of erythroid genes. ? Catechol reduced methylation levels at some CpG sites in erythroid genes.
Experimental study of the oxidation of methyl oleate in a jet-stirred reactor
Bax, Sarah; Hakka, Mohammed Hichem; Glaude, Pierre-Alexandre; Herbinet, Olivier; Battin-Leclerc, Frederique
The experimental study of the oxidation of a blend containing n-decane and a large unsaturated ester, methyl oleate, was performed in a jet-stirred reactor over a wide range of temperature covering both low and high temperature regions (550-1100 K), at a residence time of 1.5 s, at quasi atmospheric pressure with high dilution in helium (n-decane and methyl oleate inlet mole fractions of 1.48 x 10{sup -3} and 5.2 x 10{sup -4}) and under stoichiometric conditions. The formation of numerous reaction products was observed. At low and intermediate temperatures, the oxidation of the blend led to the formation of species containing oxygen atoms like cyclic ethers, aldehydes and ketones deriving from n-decane and methyl oleate. At higher temperature, these species were not formed anymore and the presence of unsaturated species was observed. Because of the presence of the double bond in the middle of the alkyl chain of methyl oleate, the formation of some specific products was observed. These species are dienes and esters with two double bonds produced from the decomposition paths of methyl oleate and some species obtained from the addition of H-atoms, OH and HO{sub 2} radicals to the double bond. Experimental results were compared with former results of the oxidation of a blend of n-decane and methyl palmitate performed under similar conditions. This comparison allowed highlighting the similarities and the differences in the reactivity and in the distribution of the reaction products for the oxidation of large saturated and unsaturated esters. (author)
Synthesis Of [2h, 13c] And [2h3, 13c]Methyl Aryl Sulfides
Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.
The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2,.sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfides wherein the .sup.13 C methyl group attached to the sulfur of the sulfide includes exactly one, two or three deuterium atoms. The present invention is also directed to the labeled compounds of [.sup.2 H.sub.1, .sup.13 C]methyl iodide and [.sup.2 H.sub.2, .sup.13 C]methyl iodide.
Polylactide?Poly(6-methyl-[espilson]-caprolactone)?Polylactide Thermoplastic Elastomers
Martello, Mark T.; Hillmyer, Marc A.
Amorphous ABA type block aliphatic polyesters can be useful as degradable and biorenewable thermoplastic elastomers. These materials can be prepared by sequential ring-opening transesterification polymerization (ROTEP) reactions and can exhibit a range of physical properties and morphologies. In this work a set of amorphous polylactide-poly(6-methyl-{epsilon}-caprolactone)-polylactide aliphatic polyester ABA triblock copolymers were prepared by consecutive controlled ring-opening polymerizations. Ring-opening polymerization of neat 6-methyl-{epsilon}-caprolactone in the presence of 1,4-benzenedimethanol and tin(II) octoate afforded {alpha},{omega}-hydroxyl-terminated poly(6-methyl-{epsilon}-caprolactone). High conversions of 6-methyl-{epsilon}-caprolactone (>96%) afforded polymers with molar masses ranging from 12 to 98 kg mol{sup -1}, depending on monomer-to-initiator ratios, polymers with narrow, monomodal molecular weight distributions. An array of polylactide-poly(6-methyl-{epsilon}-caprolactone)-polylactide triblock copolymers with controlled molecular weights and narrow molecular weight distributions were synthesized using the telechelic poly(6-methyl-{epsilon}-caprolactone) samples as macroinitiators for the ring-opening polymerization of D,L-lactide. The morphological, thermal, and mechanical behaviors of these materials were explored. Several triblocks adopted well-ordered microphase-separated morphologies, and both hexagonally packed cylindrical and lamellar structures were observed. The Flory-Huggins interaction parameter was determined, x(T) = 61.2 T{sup -1} - 0.1, based on the order-to-disorder transition temperatures of two symmetric triblocks using the calculated mean field theory result. The elastomeric mechanical behavior of two high molecular weight triblocks was characterized by tensile and elastic recovery experiments.
Isomerization and dissociation in competition: The two-component dissociation rates of methyl propionate ions
Mazyar, O.A.; Baer, T.
Threshold photoelectron-photoion coincidence (TPEPICO) spectroscopy has been used to investigate the unimolecular chemistry of gas-phase methyl propionate ions. This ion undergoes isomerization to a lower energy enol structure, CH{sub 3}CHC(OH)OCH{sub 3}{sup {sm_bullet}+}, via two different pathways involving two distonic isomers, {sup {sm_bullet}}CH{sub 2}CH{sub 2}C{sup +}(OH)OCH{sub 3} and CH{sub 3}CH{sub 2}C{sup +}(OH)OCH{sub 2}{sup {sm_bullet}}. This isomerization reaction is in competition with the direct CH{sub 3}O{sup {sm_bullet}} loss reaction, which leads to two-component dissociation rates of the methyl propionate ions. Detailed modeling of this complex reaction permitted the extraction of the dissociative photoionization threshold for methyl propionate, which at 0 K is 10.83 {+-} 0.01 eV, as well as the isomerization barrier between the distonic CH{sub 3}CH{sub 2}C{sup +}(OH)OCH{sub 2}{sup {sm_bullet}} and enol CH{sub 3}CHC(OH)OCH{sub 3}{sup {sm_bullet}+} ions of 8.5 kcal/mol (relative to the methyl propionate ion). By combining this with the 0 K heats of formation of methyl propionate and the methoxy radical, the authors derive a 0 K heat of formation of the product propanoyl ion of 147 kcal/mol. Also measured was the adiabatic ionization energy of methyl propionate, 10.03 {+-} 0.05 eV.
Crystal structure of 1-methyl-3-([2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene]methyl)urea
Habibi, A. Ghorbani, H. S.; Bruno, G.; Rudbari, H. A.; Valizadeh, Y.
The crystal structure of 1-Methyl-3-([2,2-dimethyl-4,6-dioxo-1,3-dioxane-5-ylidene]methyl)urea (C{sub 9}H{sub 12}N{sub 2}O{sub 5}) has been determined by single crystal X-ray diffraction analysis. The crystals are monoclinic, a = 5.3179(2), b = 18.6394(6), c =10.8124(3) �, ? = 100.015(2)�, Z = 4, sp. gr. P2{sub 1}/c, R = 0.0381 for 2537 reflections with I > 2?(I). Except for C(CH{sub 3}){sub 2} group, the molecule is planar. The structure is stabilized by inter- and intramolecular N-H...O hydrogen bonds and weak C-H...O interactions.
Acute environmental toxicity and persistence of methyl salicylate: A chemical agent simulant. Final report
Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, S.W.
The interactions of methyl salicylate with plant foliage and soils were assessed using aerosol/vapor exposure methods. Measurements of deposition velocity and residence times for soils and foliar surfaces are reported. Severe plant contact toxicity was observed at foliar mass-loading levels above 4 {mu}g/cm{sup 2} leaf; however, recovery was noted after four to fourteen days. Methyl salicylate has a short-term effect on soil dehydrogenase activity, but not phosphatase activity. Results of the earthworm bioassay indicated only minimal effects on survival.
Stepwise DNA Methylation Changes Are Linked to Escape from Defined Proliferation Barriers and Mammary Epithelial Cell Immortalization
Novak, Petr; Jensen, Taylor J.; Garbe, James C.; Stampfer, Martha R.; Futscher, Bernard W.
The timing and progression of DNA methylation changes during carcinogenesis are not completely understood. To develop a timeline of aberrant DNA methylation events during malignant transformation, we analyzed genome-wide DNA methylation patterns in an isogenic human mammary epithelial cell (HMEC) culture model of transformation. To acquire immortality and malignancy, the cultured finite lifespan HMEC must overcome two distinct proliferation barriers. The first barrier, stasis, is mediated by the retinoblastoma protein and can be overcome by loss of p16(INK4A) expression. HMEC that escape stasis and continue to proliferate become genomically unstable before encountering a second more stringent proliferation barrier, telomere dysfunction due to telomere attrition. Rare cells that acquire telomerase expression may escape this barrier, become immortal, and develop further malignant properties. Our analysis of HMEC transitioning from finite lifespan to malignantly transformed showed that aberrant DNA methylation changes occur in a stepwise fashion early in the transformation process. The first aberrant DNA methylation step coincides with overcoming stasis, and results in few to hundreds of changes, depending on how stasis was overcome. A second step coincides with immortalization and results in hundreds of additional DNA methylation changes regardless of the immortalization pathway. A majority of these DNA methylation changes are also found in malignant breast cancer cells. These results show that large-scale epigenetic remodeling occurs in the earliest steps of mammary carcinogenesis, temporally links DNA methylation changes and overcoming cellular proliferation barriers, and provides a bank of potential epigenetic biomarkers that mayprove useful in breast cancer risk assessment.
Hydrogen-terminated silicon nanowire photocatalysis: Benzene oxidation and methyl red decomposition
Lian, Suoyuan; School of Chemical Engineering and Materials, Dalian Polytechnic University, Dalian 116034 ; Tsang, Chi Him A.; Centre of Super Diamond and Advanced Films, City University of Hong Kong, Hong Kong ; Kang, Zhenhui; Liu, Yang; Wong, Ningbew; Lee, Shuit-Tong; Centre of Super Diamond and Advanced Films, City University of Hong Kong, Hong Kong
Graphical abstract: H-SiNWs can catalyze hydroxylation of benzene and degradation of methyl red under visible light irradiation. Highlights: Black-Right-Pointing-Pointer Hydrogen-terminated silicon nanowires were active photocatalyst in the hydroxylation of benzene under light. Black-Right-Pointing-Pointer Hydrogen-terminated silicon nanowires were also effective in the decomposition of methyl red dye. Black-Right-Pointing-Pointer The Si/SiO{sub x} core-shell structure is the main reason of the obtained high selectivity during the hydroxylation. -- Abstract: Hydrogen-terminated silicon nanowires (H-SiNWs) were used as heterogeneous photocatalysts for the hydroxylation of benzene and for the decomposition of methyl red under visible light irradiation. The above reactions were monitored by GC-MS and UV-Vis spectrophotometry, respectively, which shows 100% selectivity for the transformation of benzene to phenol. A complete decomposition of a 2 Multiplication-Sign 10{sup -4} M methyl red solution was achieved within 30 min. The high selectivity for the hydroxylation of benzene and the photodecomposition demonstrate the catalytic activity of ultrafine H-SiNWs during nanocatalysis.
Gravity and magnetic anomalies associated with Tertiary volcanism and a Proterozoic crustal boundary, Hopi Buttes volcanic field, Navajo Nation (Arizona)
Donovan-Ealy, P.F. . Geology Dept.); Hendricks, J.D. )
The Hopi Buttes volcanic field is located in the Navajo Nation of northeastern Arizona, near the southern margin of the Colorado Plateau. Explosive phreatomagmatic eruptions from late Miocene to mid-Pliocene time produced more than 300 maar-diatremes and deposited limburgite tuffs and tuff breccia and monchiquite dikes, necks and flows within a roughly circular 2,500 km[sup 2] area. The volcanic and volcaniclastic rocks make up the middle member of the Bidahochi Formation, whose lower and upper members are lacustrine and fluvial, respectively. The Bidahochi Formation overlies gently dipping Mesozoic sedimentary rocks exposed in the southwestern portion of the volcanic field. Two significant gravity and magnetic anomalies appear within the Hopi Buttes volcanic field that are unlike the signatures of other Tertiary volcanic fields on the Colorado Plateau. A circular 20 mGal negative gravity anomaly is centered over exposed sedimentary rocks in the southwestern portion of the field. The anomaly may be due to the large volume of low density pyroclastic rocks in the volcanic field and/or extensive brecciation of the underlying strata from the violent maar eruptions. The second significant anomaly is the northeast-trending Holbrook lineament, a 5 km-wide gravity and magnetic lineament that crosses the southeastern part of the volcanic field. The lineament reflects substantial gravity and magnetic decreases of 1.67 mGals/km and 100 gammas/km respectively, to the southeast. Preliminary two-dimensional gravity and magnetic modeling suggests the lineament represents a major Proterozoic crustal boundary and may correlate with one of several Proterozoic faults exposed in the transition zone of central Arizona. Gravity modeling shows a 3--5 km step'' in the Moho near the crustal boundary. The decrease in depth of the Moho to the northwest indicates either movement along the fault or magmatic upwelling beneath the volcanic field.
Impaired methylation as a novel mechanism for proteasome suppression in liver cells
Osna, Natalia A.; White, Ronda L.; Donohue, Terrence M.; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68105 ; Beard, Michael R.; Tuma, Dean J.; Kharbanda, Kusum K.; Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68105
The proteasome is a multi-catalytic protein degradation enzyme that is regulated by ethanol-induced oxidative stress; such suppression is attributed to CYP2E1-generated metabolites. However, under certain conditions, it appears that in addition to oxidative stress, other mechanisms are also involved in proteasome regulation. This study investigated whether impaired protein methylation that occurs during exposure of liver cells to ethanol, may contribute to suppression of proteasome activity. We measured the chymotrypsin-like proteasome activity in Huh7CYP cells, hepatocytes, liver cytosols and nuclear extracts or purified 20S proteasome under conditions that maintain or prevent protein methylation. Reduction of proteasome activity of hepatoma cell and hepatocytes by ethanol or tubercidin was prevented by simultaneous treatment with S-adenosylmethionine (SAM). Moreover, the tubercidin-induced decline in proteasome activity occurred in both nuclear and cytosolic fractions. In vitro exposure of cell cytosolic fractions or highly purified 20S proteasome to low SAM:S-adenosylhomocysteine (SAH) ratios in the buffer also suppressed proteasome function, indicating that one or more methyltransferase(s) may be associated with proteasomal subunits. Immunoblotting a purified 20S rabbit red cell proteasome preparation using methyl lysine-specific antibodies revealed a 25 kDa proteasome subunit that showed positive reactivity with anti-methyl lysine. This reactivity was modified when 20S proteasome was exposed to differential SAM:SAH ratios. We conclude that impaired methylation of proteasome subunits suppressed proteasome activity in liver cells indicating an additional, yet novel mechanism of proteasome activity regulation by ethanol.
Spectroscopic investigation of the vibrational quasi-continuum arising from internal rotation of a methyl group
Hougen, J.T.
The goal of this project is to use spectroscopic techniques to investigate in detail phenomena involving the vibrational quasi-continuum in a simple physical system. Acetaldehyde was chosen for the study because: (i) methyl groups have been suggested to be important promotors of intramolecular vibrational relaxation, (ii) the internal rotation of a methyl group is an easily describle large-amplitude motion, which should retain its simple character even at high levels of excitation, and (iii) the aldehyde carbonyl group offers the possibility of both vibrational and electronic probing. The present investigation of the ground electronic state has three parts: (1) understanding the {open_quotes}isolated{close_quotes} internal-rotation motion below, at, and above the top of the torsional barrier, (2) understanding in detail traditional (bond stretching and bending) vibrational fundamental and overtone states, and (3) understanding interactions involving states with multiquantum excitations of at least one of these two kinds of motion.
Method of recycling lithium borate to lithium borohydride through methyl borate
Filby, Evan E.
This invention provides a method for the recycling of lithium borate to lithium borohydride which can be reacted with water to generate hydrogen for utilization as a fuel. The lithium borate by-product of the hydrogen generation reaction is reacted with hydrogen chloride and water to produce boric acid and lithium chloride. The boric acid and lithium chloride are converted to lithium borohydride through a methyl borate intermediate to complete the recycle scheme.
Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Technology (Revised) (Presentation)
Miller, D. C.; Carloni, J. D.; Pankow, J. W.; Gjersing, E. L.; To, B.; Packard, C. E.; Kennedy, C. E.; Kurtz, S. R.
Concentrating photovoltaic (CPV) technology recently gained interest based on its expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems employ Fresnel lenses composed of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density on the cell. The optical and mechanical durability of these lenses, however, is not well established relative to the desired surface life of 30 years. Our research aims to quantify the expected lifetime of PMMA in key market locations (FL, AZ, and CO).
Proximal impact deposits at the Cretaceous-Tertiary boundary in the Gulf of Mexico: A restudy of DSDP Leg 77 Sites 536 and 540
Alvarez, W.; Asaro, F. ); Smit, J. ); Lowrie, W. ); Asaro, F. ); Margolis, S.V.; Claeys, P. ); Kastner, M. ); Hildebrand, A.R. )
Restudy of Deep Sea Drilling Project Sites 536 and 540 in the southeast Gulf of Mexico gives evidence for a giant wave at Cretaceous-Tertiary boundary time. Five units are recognized: (1) Cenomanian limestone underlies a hiatus in which the five highest Cretaceous stages are missing, possibly because of catastrophic K-T erosion. (2) Pebbly mudstone, 45 m thick, represents a submarine landslide possibly of K-T age. (3) Current-bedded sandstone, more than 2.5 m thick, contains anomalous iridium, tektite glass, and shocked quartz; it is interpreted as ejecta from a nearby impact crater, reworked on the deep-sea floor by the resulting tsunami. (4) A 50-cm interval of calcareous mudstone containing small Cretaceous planktic foraminifera and the Ir peak is interpreted as the silt-size fraction of the Cretaceous material suspended by the impact-generated wave. (5) Calcareous mudstone with basal Tertiary forams and the uppermost tail of the Ir anomaly overlies the disturbed interval, dating the impact and wave event as K-T boundary age. Like Beloc in Haiti and Mimbral in Mexico, Sites 536 and 540 are consistent with a large K-T age impact at the nearby Chicxulub crater.
Crystallization of lysozyme with (R)-, (S)- and (RS)-2-methyl-2, 4-pentanediol
Stauber, Mark; Jakoncic, Jean; Berger, Jacob; Karp, Jerome M.; Axelbaum, Ariel; Sastow, Dahniel; Buldyrev, Sergey V.; Hrnjez, Bruce J.; Asherie, Neer
Crystallization of lysozyme with (R)-2-methyl-2, 4-pentanediol produces more ordered crystals and a higher resolution protein structure than crystallization with (S)-2-methyl-2, 4-pentanediol. The results suggest that chiral interactions with chiral additives are important in protein crystal formation. Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2, 4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozyme and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.
Sub-crop geologic map of pre-Tertiary rocks in the Yucca Flat and northern Frenchman Flat areas, Nevada Test Site, southern Nevada
Cole, J.C.; Harris, A.G.; Wahl, R.R.
This map displays interpreted structural and stratigraphic relations among the Paleozoic and older rocks of the Nevada Test Site region beneath the Miocene volcanic rocks and younger alluvium in the Yucca Flat and northern Frenchman Flat basins. These interpretations are based on a comprehensive examination and review of data for more than 77 drillholes that penetrated part of the pre-Tertiary basement beneath these post-middle Miocene structural basins. Biostratigraphic data from conodont fossils were newly obtained for 31 of these holes, and a thorough review of all prior microfossil paleontologic data is incorporated in the analysis. Subsurface relationships are interpreted in light of a revised regional geologic framework synthesized from detailed geologic mapping in the ranges surrounding Yucca Flat, from comprehensive stratigraphic studies in the region, and from additional detailed field studies on and around the Nevada Test Site. All available data indicate the subsurface geology of Yucca Flat is considerably more complicated than previous interpretations have suggested. The western part of the basin, in particular, is underlain by relics of the eastward-vergent Belted Range thrust system that are folded back toward the west and thrust by local, west-vergent contractional structures of the CP thrust system. Field evidence from the ranges surrounding the north end of Yucca Flat indicate that two significant strike-slip faults track southward beneath the post-middle Miocene basin fill, but their subsurface traces cannot be closely defined from the available evidence. In contrast, the eastern part of the Yucca Flat basin is interpreted to be underlain by a fairly simple north-trending, broad syncline in the pre-Tertiary units. Far fewer data are available for the northern Frenchman Flat basin, but regional analysis indicates the pre-Tertiary structure there should also be relatively simple and not affected by thrusting. This new interpretation has implications
Structural basis for recognition of hemi-methylated DNA by the SRA domain of human UHRF1.
Avvakumov, George V.; Walker, John R.; Xue, Sheng; Li, Yanjun; Duan, Shili; Bronner, Christian; Arrowsmith, Cheryl H.; Dhe-Paganon, Sirano
Epigenetic inheritance in mammals is characterized by high-fidelity replication of CpG methylation patterns during development. UHRF1 (also known as ICBP90 in humans and Np95 in mouse) is an E3 ligase important for the maintenance of global and local DNA methylation in vivo. The preferential affinity of UHRF1 for hemi-methylated DNA over symmetrically methylated DNA by means of its SET and RING-associated (SRA) domain and its association with the maintenance DNA methyltransferase 1 (DNMT1) suggests a role in replication of the epigenetic code. Here we report the 1.7 {angstrom} crystal structure of the apo SRA domain of human UHRF1 and a 2.2 {angstrom} structure of its complex with hemi-methylated DNA, revealing a previously unknown reading mechanism for methylated CpG sites (mCpG). The SRA-DNA complex has several notable structural features including a binding pocket that accommodates the 5-methylcytosine that is flipped out of the duplex DNA. Two specialized loops reach through the resulting gap in the DNA from both the major and the minor grooves to read the other three bases of the CpG duplex. The major groove loop confers both specificity for the CpG dinucleotide and discrimination against methylation of deoxycytidine of the complementary strand. The structure, along with mutagenesis data, suggests how UHRF1 acts as a key factor for DNMT1 maintenance methylation through recognition of a fundamental unit of epigenetic inheritance, mCpG.
Spatial and Functional Relationships Among Pol V-Associated loci, Pol IV-Dependent siRNAs, and Cytosine Methylation in the Arabidopsis Epigenome
Wierzbicki, A. T.; Cocklin, Ross; Mayampurath, Anoop; Lister, Ryan; Rowley, M. J.; Gregory, Brian D.; Ecker, Joseph R.; Tang, Haixu; Pikaard, Craig S.
Multisubunit RNA polymerases IV and V (Pols IV and V) mediate RNA-directed DNA methylation and transcriptional silencing of retrotransposons and heterochromatic repeats in plants. We identified genomic sites of Pol V occupancy in parallel with siRNA deep sequencing and methylcytosine mapping, comparing wild-type plants with mutants defective for Pol IV, Pol V, or both Pols IV and V. Approximately 60% of Pol V-associated regions encompass regions of 24-nucleotide (nt) siRNA complementarity and cytosine methylation, consistent with cytosine methylation being guided by base-pairing of Pol IV-dependent siRNAs with Pol V transcripts. However, 27% of Pol V peaks do not overlap sites of 24-nt siRNA biogenesis or cytosine methylation, indicating that Pol V alone does not specify sites of cytosine methylation. Surprisingly, the number of methylated CHH motifs, a hallmark of RNA-directed de novo methylation, is similar in wild-type plants and Pol IV or Pol V mutants. In the mutants, methylation is lost at 50%-60% of the CHH sites that are methylated in the wild type but is gained at new CHH positions, primarily in pericentromeric regions. These results indicate that Pol IV and Pol V are not required for cytosine methyltransferase activity but shape the epigenome by guiding CHH methylation to specific genomic sites.
The interaction of organic adsorbate vibrations with substrate lattice waves in methyl-Si(111)-(1?�?1)
Brown, Ryan D.; Hund, Zachary M.; Sibener, S. J.; Campi, Davide; Bernasconi, M.; O�Leary, Leslie E.; Lewis, Nathan S.; Benedek, G.
A combined helium atom scattering and density functional perturbation theory study has been performed to elucidate the surface phonon dispersion relations for both the CH{sub 3}-Si(111)-(1?�?1) and CD{sub 3}-Si(111)-(1?�?1) surfaces. The combination of experimental and theoretical methods has allowed characterization of the interactions between the low energy vibrations of the adsorbate and the lattice waves of the underlying substrate, as well as characterization of the interactions between neighboring methyl groups, across the entire wavevector resolved vibrational energy spectrum of each system. The Rayleigh wave was found to hybridize with the surface rocking libration near the surface Brillouin zone edge at both the M{sup �}-point and K{sup �}-point. The calculations indicated that the range of possible energies for the potential barrier to the methyl rotation about the Si-C axis is sufficient to prevent the free rotation of the methyl groups at a room temperature interface. The density functional perturbation theory calculations revealed several other surface phonons that experienced mode-splitting arising from the mutual interaction of adjacent methyl groups. The theory identified a Lucas pair that exists just below the silicon optical bands. For both the CH{sub 3}- and CD{sub 3}-terminated Si(111) surfaces, the deformations of the methyl groups were examined and compared to previous experimental and theoretical work on the nature of the surface vibrations. The calculations indicated a splitting of the asymmetric deformation of the methyl group near the zone edges due to steric interactions of adjacent methyl groups. The observed shifts in vibrational energies of the -CD{sub 3} groups were consistent with the expected effect of isotopic substitution in this system.
Lithium cycling performance in improved lithium hexafluoroarsenate/2-Methyl tetrahydrofuran electrolytes
Desjardins, C.D.; Cadge, T.G.; Casey, E.J.; Donaldson, G.; Salter, R.S.
Lithium hexafluoroarsenate/2-methyl tetrahydrofuran electrolytes have been prepared, purified, and evaluated using half-cell galvanostatic lithium cycling, cyclic voltammetry, plus colorimetric, gas chromatographic, and UV absorption techniques. Superior electrolytes have been prepared yielding reproducible cycling efficiencies in excess of 97%. Static aging trials at ambient temperature clearly demonstrate deterioration in cycling performance with time. This decline in performance is related to electrolyte degradation, possibly arising from the formation of peroxides. However, studies of various battery testing regimes on 1M LiAsF/sub 6//2Me-THF electrolyte support the system' battery potential with respect to both rate capability and shelf-life characteristics.
Organic Carbon Transformation and Mercury Methylation in Tundra Soils from Barrow Alaska
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Liang, L.; Wullschleger, Stan; Graham, David; Gu, B.; Yang, Ziming
This dataset includes information on soil labile organic carbon transformation and mercury methylation for tundra soils from Barrow, Alaska. The soil cores were collected from high-centered polygon (trough) at BEO and were incubated under anaerobic laboratory conditions at both freezing and warming temperatures for up to 8 months. Soil organic carbon including reducing sugars, alcohols, and organic acids were analyzed, and CH4 and CO2 emissions were quantified. Net production of methylmercury and Fe(II)/Fe(total) ratio were also measured and provided in this dataset.
Continuous realtime radioiodine monitor employing on-line methyl iodide conversion
Fernandez, S.J.; Motes, B.G.
An integrated /sup 14/C, /sup 129/I, and /sup 85/Kr monitor was proposed by Fernandez, et al. that separates /sup 129/I from /sup 85/Kr by selective permeation across thin silicone rubber membranes. Subsequent studies of the permeation of CH/sub 3/I and I/sub 2/ through silicone rubber membranes demonstrated that I/sub 2/ transport across the membranes is too slow to be useful in a realtime monitor. Transport of methyl iodide, however, is rapid and gives a separation factor of greater than 100 from /sup 85/Kr.
Low-lying excited states and nonradiative processes of 9-methyl-2-aminopurine
Trachsel, Maria A.; Lobsiger, Simon; Sch�r, Tobias; Leutwyler, Samuel
The UV spectrum of the adenine analogue 9-methyl-2-aminopurine (9M-2AP) is investigated with one- and two-color resonant two-photon ionization spectroscopy at 0.3 and 0.05 cm{sup ?1} resolution in a supersonic jet. The electronic origin at 32�252 cm{sup ?1} exhibits methyl torsional subbands that originate from the 0A{sub 1}{sup ??} (l = 0) and 1E{sup ?} (l = �1) torsional levels. These and further torsional bands that appear up to 0{sub 0}{sup 0}+230 cm{sup ?1} allow to fit the threefold (V{sub 3}) barriers of the torsional potentials as |V{sub 3}{sup ??}|=50 cm{sup ?1} in the S{sub 0} and |V{sub 3}{sup ?}|=126 cm{sup ?1} in the S{sub 1} state. Using the B3LYP density functional and correlated approximate second-order coupled cluster CC2 methods, the methyl orientation is calculated to be symmetric relative to the 2AP plane in both states, with barriers of V{sub 3}{sup ??}=20 cm{sup ?1} and V{sub 3}{sup ?}=115 cm{sup ?1}. The 0{sub 0}{sup 0} rotational band contour is 75% in-plane (a/b) polarized, characteristic for a dominantly long-axis {sup 1}??{sup *} excitation. The residual 25% c-axis polarization may indicate coupling of the {sup 1}??{sup *} to the close-lying {sup 1}n?{sup *} state, calculated at 4.00 and 4.01 eV with the CC2 method. However, the CC2 calculated {sup 1}n? oscillator strength is only 6% of that of the {sup 1}??{sup *} transition. The {sup 1}??{sup *} vibronic spectrum is very complex, showing about 40 bands within the lowest 500 cm{sup ?1}. The methyl torsion and the low-frequency out-of-plane ?{sub 1}{sup ?} and ?{sub 2}{sup ?} vibrations are strongly coupled in the {sup 1}??{sup *} state. This gives rise to many torsion-vibration combination bands built on out-of-plane fundamentals, which are without precedence in the {sup 1}??{sup *} spectrum of 9H-2-aminopurine [S. Lobsiger, R. K. Sinha, M. Trachsel, and S. Leutwyler, J. Chem. Phys. 134, 114307 (2011)]. From the Lorentzian broadening needed to fit the 0{sub 0}{sup 0} contour of 9M-2AP
Theory of long-lived nuclear spin states in methyl groups and quantum-rotor induced polarisation
Dumez, Jean-Nicolas; Håkansson, Pär; Mamone, Salvatore; Meier, Benno; Stevanato, Gabriele; Hill-Cousins, Joseph T.; Roy, Soumya Singha; Brown, Richard C. D.; Pileio, Giuseppe; Levitt, Malcolm H.
Long-lived nuclear spin states have a relaxation time much longer than the longitudinal relaxation time T{sub 1}. Long-lived states extend significantly the time scales that may be probed with magnetic resonance, with possible applications to transport and binding studies, and to hyperpolarised imaging. Rapidly rotating methyl groups in solution may support a long-lived state, consisting of a population imbalance between states of different spin exchange symmetries. Here, we expand the formalism for describing the behaviour of long-lived nuclear spin states in methyl groups, with special attention to the hyperpolarisation effects observed in {sup 13}CH{sub 3} groups upon rapidly converting a material with low-barrier methyl rotation from the cryogenic solid state to a room-temperature solution [M. Icker and S. Berger, J. Magn. Reson. 219, 1 (2012)]. We analyse the relaxation properties of methyl long-lived states using semi-classical relaxation theory. Numerical simulations are supplemented with a spherical-tensor analysis, which captures the essential properties of methyl long-lived states.
Dipole Alignment at the Carbon Nanotube and Methyl Ammonium Lead Iodide Perovskite Interface
Przepioski, Joshua
This work correlates resonant peaks from first principles calculation on ammonia (NH3) Nitrogen 1s x-ray absorption spectroscopy (XAS) within the methyl ammonium lead iodide perovskite (CH3NH3PbI3), and proposes a curve to determine the alignment of the methyl ammonium dipole if there exists angular dependence. The Nitrogen 1s XAS was performed at varying incident angles on the perovskite with and without a carbon nanotube (CNT) interface produced from an ultrasonic spray deposition. We investigated the peak contribution from PbI2 and the poly(9,9-dioctylfluorene- 2,7-diyl) with bipyridine (PFO-BPy) wrapped around the CNT, and used normalization techniques to better identify the dipole alignment. There was angular dependence on samples containing the CNT interface suggesting an existing dipole alignment, but there was no angular dependence on the perovskite samples alone; however, more normalization techniques and experimental work must be performed in order to ensure its validity and to better describe its alignment, and possible controlling factors.
Autoignition measurements and a validated kinetic model for the biodiesel surrogate, methyl butanoate
Dooley, S.; Curran, H.J.; Simmie, J.M.
The autoignition of methyl butanoate has been studied at 1 and 4 atm in a shock tube over the temperature range 1250-1760 K at equivalence ratios of 1.5, 1.0, 0.5, and 0.25 at fuel concentrations of 1.0 and 1.5%. These measurements are complemented by autoignition data from a rapid compression machine over the temperature range 640-949 K at compressed gas pressures of 10, 20, and 40 atm and at varying equivalence ratios of 1.0, 0.5, and 0.33 using fuel concentrations of 1.59 and 3.13%. The autoignition of methyl butanoate is observed to follow Arrhenius-like temperature dependence over all conditions studied. These data, together with speciation data reported in the literature in a flow reactor, a jet-stirred reactor, and an opposed-flow diffusion flame, were used to produce a detailed chemical kinetic model. It was found that the model correctly simulated the effect of change in equivalence ratio, fuel fraction, and pressure for shock tube ignition delays. The agreement with rapid compression machine ignition delays is less accurate, although the qualitative agreement is reasonable. The model reproduces most speciation data with good accuracy. In addition, the important reaction pathways over each regime have been elucidated by both sensitivity and flux analyses. (author)
Production of FAME biodiesel in E. coli by direct methylation with an insect enzyme
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Sherkhanov, Saken; Korman, Tyler P.; Clarke, Steven G.; Bowie, James U.
Here, most biodiesel currently in use consists of fatty acid methyl esters (FAMEs) produced by transesterification of plant oils with methanol. To reduce competition with food supplies, it would be desirable to directly produce biodiesel in microorganisms. To date, the most effective pathway for the production of biodiesel in bacteria yields fatty acid ethyl esters (FAEEs) at up to ~1.5 g/L. A much simpler route to biodiesel produces FAMEs by direct S-adenosyl-L-methionine (SAM) dependent methylation of free fatty acids, but FAME production by this route has been limited to only ~16 mg/L. Here we employ an alternative, broad spectrum methyltransferase,more » Drosophila melanogaster Juvenile Hormone Acid O-Methyltransferase (DmJHAMT). By introducing DmJHAMT in E. coli engineered to produce medium chain fatty acids and overproduce SAM, we obtain medium chain FAMEs at titers of 0.56 g/L, a 35-fold increase over titers previously achieved. Although considerable improvements will be needed for viable bacterial production of FAMEs and FAEEs for biofuels, it may be easier to optimize and transport the FAME production pathway to other microorganisms because it involves fewer enzymes.« less
Methyl chloride via oxyhydrochlorination of methane: A building block for chemicals and fuels from natural gas
Benson, R.L.; Brown, S.S.D.; Ferguson, S.P.; Jarvis, R.F. Jr.
The objectives of this program are to (a) develop a process for converting natural gas to methyl chloride via an oxyhydrochlorination route using highly selective, stable catalysts in a fixed-bed, (b) design a reactor capable of removing the large amount of heat generated in the process so as to control the reaction, (c) develop a recovery system capable of removing the methyl chloride from the product stream and (d) determine the economics and commercial viability of the process. The general approach has been as follows: (a) design and build a laboratory scale reactor, (b) define and synthesize suitable OHC catalysts for evaluation, (c) select first generation OHC catalyst for Process Development Unit (PDU) trials, (d) design, construct and startup PDU, (e) evaluate packed bed reactor design, (f) optimize process, in particular, product recovery operations, (g) determine economics of process, (h) complete preliminary engineering design for Phase II and (i) make scale-up decision and formulate business plan for Phase II. Conclusions regarding process development and catalyst development are presented.
Arbuzov rearrangement in alkoxy derivatives and chloro derivatives of methyl phosphonites
Livantsov, M.V.; Prishchenko, A.A.; Lutsenko, I.F.
In a series of alkoxy- and chloro-substituted methyl phosphonites, the Arbuzov reaction is a preparative method for the synthesis of new types of functionally substituted methyl phosphinates. The Arbuzov reaction takes a new pathway in the case of dialkoxymethyl phosphonites, in which the phosphorus-carbon bond is ruptured at the stage where a quasiphosphonium compound forms, producing alkoxycarbonyl phosphonites that have not been available before. The IR spectra were obtained on UR-20 and IKS-22 instruments in a thin layer (NaCL). The PMR spectra were taken on a Tesla BS-497 spectrometer (100 MHz) in C/sub 6/D/sub 6/ and CDCl/sub 3/ solutions (20 to 30% concn.), with TMS as standard. The /sup 13/C NMR spectrum of phosphonite (XI) was obtained on a Varian FT-80A spectrometer (20 MHz) in an 80% solution in C/sub 6/D/sub 6/ and with TMS as standard. The /sup 31/P NMR spectra were obtained on JEOL 6-50OHL (24.3 MHz), Varian FT-80A (32.2 MHz), and JOEL FX-100 (42 MHz) spectrometers with an 85% solution of H/sub 3/PO/sub 4/ in D/sub 2/O as standard.
Covalent Coupling of Organophosphorus Hydrolase Loaded Quantum Dots to Carbon Nanotube/Au Nanocomposite for Enhanced Detection of Methyl Parathion
Du, Dan; Chen, Wenjuan; Zhang, Weiying; Liu, Deli; Li, Haibing; Lin, Yuehe
An amperometric biosensor for highly selective and sensitive determination of methyl parathion (MP) was developed based on dual signal amplification: (1) a large amount of introduced enzyme on the electrode surface and (2) synergistic effects of nanoparticles towards enzymatic catalysis. The fabrication process includes (1) electrochemical deposition of gold nanoparticles by a multi-potential step technique at multiwalled carbon nanotube (MWCNT) film pre-cast on a glassy carbon electrode and (2) immobilization of methyl parathion degrading enzyme (MPDE) onto a modified electrode through CdTe quantum dots (CdTe QDs) covalent attachment. The introduced MWCNT and gold nanoparticles significantly increased the surface area and exhibited synergistic effects towards enzymatic catalysis. CdTe QDs are further used as carriers to load a large amount of enzyme. As a result of these two important enhancement factors, the proposed biosensor exhibited extremely sensitive, perfectly selective, and rapid response to methyl parathion in the absence of a mediator.
Reactions of methyl groups on a non-reducible metal oxide: The reaction of iodomethane on stoichiometric α-Cr2O3(0001)
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.
The reaction of iodomethane on the nearly stoichiometric α-Cr2O3(0001) surface produces gas phase ethylene, methane, and surface iodine adatoms. The reaction is first initiated by the dissociation of iodomethane into surface methyl fragments, -CH3, and iodine adatoms. Methyl fragments bound at surface Cr cation sites undergo a rate-limiting dehydrogenation reaction to methylene, =CH2. The methylene intermediates formed from methyl dehydrogenation can then undergo coupling reactions to produce ethylene via two principle reaction pathways: (1) direct coupling of methylene and (2) methylene insertion into the methyl surface bond to form surface ethyl groups which undergo β-H elimination to produce ethylene. Themore » liberated hydrogen also combines with methyl groups to form methane. Iodine adatoms from the dissociation of iodomethane deactivate the surface by simple site blocking of the surface Cr3+ cations.« less
Reactions of methyl groups on a non-reducible metal oxide: The reaction of iodomethane on stoichiometric ?-Cr2O3(0001)
Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.
The reaction of iodomethane on the nearly stoichiometric ?-Cr2O3(0001) surface produces gas phase ethylene, methane, and surface iodine adatoms. The reaction is first initiated by the dissociation of iodomethane into surface methyl fragments, -CH3, and iodine adatoms. Methyl fragments bound at surface Cr cation sites undergo a rate-limiting dehydrogenation reaction to methylene, =CH2. The methylene intermediates formed from methyl dehydrogenation can then undergo coupling reactions to produce ethylene via two principle reaction pathways: (1) direct coupling of methylene and (2) methylene insertion into the methyl surface bond to form surface ethyl groups which undergo ?-H elimination to produce ethylene. The liberated hydrogen also combines with methyl groups to form methane. Iodine adatoms from the dissociation of iodomethane deactivate the surface by simple site blocking of the surface Cr3+ cations.
Heterogeneous catalyst for the production of acetic anhydride from methyl acetate
Ramprasad, D.; Waller, F.J.
This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.
Heterogeneous catalyst for the production of acetic anhydride from methyl acetate
Ramprasad, Dorai; Waller, Francis Joseph
This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.
Methyl Chloride from Direct Methane Partial Oxidation: A High-Temperature Shilov-Like Catalytic System
Yongchun Tang; John Ma
The intention of this study is to demonstrate and evaluate the scientific and economic feasibility of using special solvents to improve the thermal stability of Pt-catalyst in the Shilov system, such that a high reaction temperature could be achieved. The higher conversion rate (near 100%) of methyl chloride from partial oxidation of methane under the high temperature ({approx} 200 C) without significant Pt0 precipitation has been achieved. High concentration of the Cl- ion has been identified as the key for the stabilization of the Pt-catalysts. H/D exchange measurements indicated that the over oxidation will occur at the elevated temperature, developments of the effective product separation processes will be necessary in order to rationalize the industry-visible CH4 to CH3Cl conversion.
Mesoscale simulation of shocked poly-(4-methyl-1-pentene) (PMP) foams.
Schroen, Diana Grace; Flicker, Dawn G.; Haill, Thomas A.; Root, Seth; Mattsson, Thomas Kjell Rene
Hydrocarbon foams are commonly used in HEDP experiments, and are subject to shock compression from tens to hundreds of GPa. Modeling foams is challenging due to the heterogeneous character of the foam. A quantitative understanding of foams under strong dynamic compression is sought. We use Sandia's ALEGRA-MHD code to simulate 3D mesoscale models of pure poly(4-methyl-1-petene) (PMP) foams. We employ two models of the initial polymer-void structure of the foam and analyze the statistical properties of the initial and shocked states. We compare the simulations to multi-Mbar shock experiments at various initial foam densities and flyer impact velocities. Scatter in the experimental data may be a consequence of the initial foam inhomogeneity. We compare the statistical properties the simulations with the scatter in the experimental data.
Crystallization of lysozyme with (R)-, (S)- and (RS)-2-methyl-2,4-pentanediol
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Stauber, Mark; Jakoncic, Jean; Berger, Jacob; Karp, Jerome M.; Axelbaum, Ariel; Sastow, Dahniel; Buldyrev, Sergey V.; Hrnjez, Bruce J.; Asherie, Neer
Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2,4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozymemore » and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.« less
Tuning of cross-linking and mechanical properties of laser-deposited poly (methyl methacrylate) films
Sueske, Erik; Scharf, Thorsten; Krebs, Hans-Ulrich; Panchenko, Elena; Junkers, Thomas; Egorov, Mark; Buback, Michael; Kijewski, Harald
The chemical composition, amount of cross-linking and its influence on the mechanical properties of poly(methyl methacrylate) (PMMA) thin films produced by pulsed laser deposition (PLD) at a wavelength of 248 nm under ultrahigh vacuum were investigated by infrared spectroscopy, scanning electron microscopy, size-exclusion chromatography, thermogravimetric analysis, and nanoindentation experiments. The films consist of two components, one fraction with a molecular weight well below that of the target material and a second fraction, which is cross-linked. Compared to bulk material, the Young's modulus of the film is increased. The amount of cross-linking in the film can be tuned by the applied laser fluence leading to changes of the mechanical properties.
Interactions in 1-ethyl-3-methyl imidazolium tetracyanoborate ion pair: Spectroscopic and density functional study
Mao, James X; Lee, Anita S; Kitchin, John R; Nulwala, Hunaid B; Luebke, David R; Damodaran, Krishnan
Density Functional Theory is used to investigate a weakly coordinating room-temperature ionic liquid, 1-ethyl-3-methyl imidazolium tetracyanoborate ([Emim]{sup +}[TCB]{sup -}). Four locally stable conformers of the ion pair were located. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of several hydrogen bonds. Further investigation through the Natural Bond Orbital (NBO) and Natural Energy Decomposition Analysis (NEDA) calculations provided insight into the origin of interactions in the [Emim]{sup +}[TCB]{sup -} ion pair. Strength of molecular interactions in the ionic liquid was correlated with frequency shifts of the characteristic vibrations of the ion pair. Harmonic vibrations of the ion pair were also compared with the experimental Raman and Infrared spectra. Vibrational frequencies were assigned by visualizing displacements of atoms around their equilibrium positions and through Potential Energy Distribution (PED) analysis.
Investigation of methyl decanoate combustion in an optical direct-injection diesel engine
Cheng, A. S.; Dumitrescu, Cosmin E.; Mueller, Charles J.
In this study, an optically accessible heavy-duty diesel engine was used to investigate the impact of methyl decanoate (MD) on combustion and emissions. A specific goal of the study was to determine if MD could enable soot-free leaner-lifted flame combustion (LLFC) – a mode of mixing-controlled combustion associated with fuel-air equivalence ratios below approximately two. An ultra-low sulfur diesel certification fuel (CF) was used as the baseline fuel, and experiments were conducted at two fuel-injection pressures with three levels of charge-gas dilution. In addition to conventional pressure-based and engine-out emissions measurements, exhaust laser-induced incandescence, in-cylinder natural luminosity (NL), and in-cylinder chemiluminescence (CL) diagnostics were used to provide detailed insight into combustion processes.
Investigation of methyl decanoate combustion in an optical direct-injection diesel engine
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Cheng, A. S.; Dumitrescu, Cosmin E.; Mueller, Charles J.
In this study, an optically accessible heavy-duty diesel engine was used to investigate the impact of methyl decanoate (MD) on combustion and emissions. A specific goal of the study was to determine if MD could enable soot-free leaner-lifted flame combustion (LLFC) – a mode of mixing-controlled combustion associated with fuel-air equivalence ratios below approximately two. An ultra-low sulfur diesel certification fuel (CF) was used as the baseline fuel, and experiments were conducted at two fuel-injection pressures with three levels of charge-gas dilution. In addition to conventional pressure-based and engine-out emissions measurements, exhaust laser-induced incandescence, in-cylinder natural luminosity (NL), and in-cylindermore » chemiluminescence (CL) diagnostics were used to provide detailed insight into combustion processes.« less
Interfacial hydrothermal synthesis of SnO{sub 2} nanorods towards photocatalytic degradation of methyl orange
Hou, L.R. Lian, L.; Zhou, L.; Zhang, L.H.; Yuan, C.Z.
Highlights: � Efficient interfacial hydrothermal strategy was developed. � 1D SnO{sub 2} nanorods as an advanced photocatalyst. � SnO{sub 2} nanorods exhibit photocatalytic degradation of the MO. - Abstract: One-dimensional (1D) SnO{sub 2} nanorods (NRs) have been successfully synthesized by means of an efficient interfacial hydrothermal strategy. The resulting product was physically characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscope, etc. The as-fabricated SnO{sub 2} NRs exhibited excellent photocatalytic degradation of the methyl orange with high degradation efficiency of 99.3% with only 60 min ultra violet light irradiation. Meanwhile, the 1D SnO{sub 2} NRs exhibited intriguing photostability after four recycles.
Homogeneous Hydrogenation of CO? to Methyl Formate Utilizing Switchable Ionic Liquids
Yadav, Mahendra; Linehan, John C.; Karkamkar, Abhijeet J.; Van Der Eide, Edwin F.; Heldebrant, David J.
Capture of CO? and subsequent hydrogenation allows for base/alcohol-catalyzed conversion of CO? to methylformate in one pot. The conversion of CO? proceeds via alkylcarbonates, to formate salts and then formate esters, which can be catalyzed by base and alcohol with the only byproduct being water. The system operates at mild conditions (300 psi H?, 140 �C). Reactivity is strongly influenced by temperature and choice of solvent. In the presence of excess of base (DBU) formate is predominant product while in excess of methanol methyl formate is major product. 110 �C yields formate salts, 140 �C promotes methylformate. The authors acknowledge internal Laboratory Directed Re-search and Development (LDRD) funding from Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the U.S. Department of Energy.
Generation kinetics of color centers in irradiated poly(4-methyl-1-pentene)
Peng, J. S.; Li, C. L.; Lee, Sanboh; Chou, K. F.
The transient absorbance of poly(4-methyl-1-pentene) (PMP) irradiated with gamma rays at elevated temperatures has been investigated. The absorbance in the ultraviolet and visible range increases with gamma ray dose. A bathochromic shift in transmission spectra emerges significantly upon irradiation. A first-order generation model is proposed to analyze the kinetics of color centers during annealing. The activation energy of the color center increases with increasing gamma ray dose. The equilibrium behavior of color centers in PMP is similar to that of vacancies in metals, and the formation energy of color centers in PMP decreases with increasing gamma ray dose. However, annealable color centers are not observed in this study.
Noncovalently-functionalized reduced graphene oxide sheets by water-soluble methyl green for supercapacitor application
Ren, Xiaoying; Hu, Zhongai Hu, Haixiong; Qiang, Ruibin; Li, Li; Li, Zhimin; Yang, Yuying; Zhang, Ziyu; Wu, Hongying
Graphical abstract: Electroactive methyl green (MG) is selected to functionalize reduced graphene oxide (RGO) through non-covalent modification and the composite achieves high specific capacitance, good rate capability and excellent long life cycle. - Highlights: • MG–RGO composites were firstly prepared through non-covalent modification. • The mass ratio in composites is a key for achieving high specific capacitance. • MG–RGO 5:4 exhibits the highest specific capacitance of 341 F g{sup −1}. • MG–RGO 5:4 shows excellent rate capability and long life cycle. - Abstract: In the present work, water-soluble electroactive methyl green (MG) has been used to non-covalently functionalize reduced graphene oxide (RGO) for enhancing supercapacitive performance. The microstructure, composition and morphology of MG–RGO composites are systematically characterized by UV–vis absorption, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical performances are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS). The fast redox reactions from MG could generate additional pseudocapacitance, which endows RGO higher capacitances. As a result, the MG–RGO composite (with the 5:4 mass ratio of MG:RGO) achieve a maximum value of 341 F g{sup −1} at 1 A g{sup −1} within the potential range from −0.25 to 0.75 V and provide a 180% enhancement in specific capacitance in comparison with pure RGO. Furthermore, excellent rate capability (72% capacitance retention from 1 A g{sup −1} to 20 A g{sup −1}) and long life cycle (12% capacitance decay after 5000 cycles) are achieved for the MG–RGO composite electrode.
Enantioselective hydrogenation. III. Methyl pyruvate hydrogenation catalyzed by alkaloid-modified iridium
Simons, K.E.; Johnston, P.; Plum, H.; Wells, P.B.; Ibbotson, A.
Enantioselective hydrogenation of methyl pyruvate, MeCOCOOMe to methyl lactate, MeCH(OH)COOMe, is catalyzed in solution at room temperature by supported iridium catalysts modified with cinchona alkaloids. Modification with cinchonidine or quinine yields R-lactate in excess, whereas modification with cinchonine or quinidine favors S-lactate formation. Ir/SiO{sub 2} catalysts (20%) calcined at 393 to 573 K and reduced at 523 to 593 K were highly active for racemic hydrogenation in the absence of a modifier (rates typically 1.8 mol h{sup -1} g{sub cat}{sup -1}) and were comparably active when modified with cinchonidine but gave an enantiomeric excess of about 30%. Use of higher calcination or reduction temperatures led to substantially inferior activity and selectivity. The high rates recorded for both racemic and enantioselective reactions are dependent on the catalysts being activated before use by a procedure involving exposure of the catalyst to air after the initial reduction. Use of a Cl-free precursor gave an Ir/SiO{sub 2} catalyst (20%) of superior activity but inferior enantioselectivity. Ir/CaCO{sub 3} (5%) was more active for racemic hydrogenation than for enantioselective hydrogenation, but provided the highest value of the enantiomeric excess 39%. Kinematics of reaction are reported. Exchange of H for D in 10,11-dihydrocinchonidine at room temperature over Ir/CaCO{sub 3} occurred in the quinoline moiety but not in the quinuclidine ring system, indicating that the alkaloid was adsorbed to the Ir surface via the interaction of its {pi}-electron system. For both silica-supported and calcium carbonate-supported Ir, the presence of chloride ion in the catalyst was advantageous for the achievement of enantioselectivity. 25 refs., 2 figs., 3 tabs.
Insights antifibrotic mechanism of methyl palmitate: Impact on nuclear factor kappa B and proinflammatory cytokines
Mantawy, Eman M.; Tadros, Mariane G.; Awad, Azza S.; Hassan, Dina A.A.; El-Demerdash, Ebtehal
Fibrosis accompanies most chronic liver disorders and is a major factor contributing to hepatic failure. Therefore, the need for an effective treatment is evident. The present study was designed to assess the potential antifibrotic effect of MP and whether MP can attenuate the severity of oxidative stress and inflammatory response in chronic liver injury. Male albino rats were treated with either CCl{sub 4} (1 ml/kg, twice a week) and/or MP (300 mg/kg, three times a week) for six weeks. CCl{sub 4}-intoxication significantly increased liver weight, serum aminotransferases, total cholesterol and triglycerides while decreased albumin level and these effects were prevented by co-treatment with MP. As indicators of oxidative stress, CCl{sub 4}-intoxication caused significant glutathione depletion and lipid peroxidation while MP co-treatment preserved them within normal values. As markers of fibrosis, hydroxyproline content and ?-SMA expression increased markedly in the CCl{sub 4} group and MP prevented these alterations. Histopathological examination by both light and electron microscope further confirmed the protective efficacy of MP. To elucidate the antifibrotic mechanisms of MP, the expression of NF-?B, iNOS and COX-2 and the tissue levels of TNF-? and nitric oxide were assessed; CCl{sub 4} increased the expression of NF-?B and all downstream inflammatory cascade while MP co-treatment inhibited them. Collectively these findings indicate that MP possesses a potent antifibrotic effect which may be partly a consequence of its antioxidant and anti-inflammatory properties. -- Highlights: ? Methyl palmitate is free fatty acid methyl ester. ? It possesses a strong antifibrotic effect. ? It inhibits NF-?B and the consequent proinflammatory and oxidative stress response.
Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP)
Van Wychen, S.; Laurens, L. M. L.
This procedure is based on a whole biomass transesterification of lipids to fatty acid methyl esters to represent an accurate reflection of the potential of microalgal biofuels. Lipids are present in many forms and play various roles within an algal cell, from cell membrane phospholipids to energy stored as triacylglycerols.
NMR Analysis of Methyl Groups at 100-500 kDa: Model Systems and Arp2/3 Complex
Kreishman-Deitrick, Mara; Egile, Coumaran; Hoyt, David W.; Ford, Joseph J.; Rong, Li; Rosen, Michael K.
Large macromolecular machines are among the most important and challenging targets for structural and mechanistic analyses. Consequently, there is great interest in development of NMR methods for the study of multicomponent systems in the 50-500 kDa range. Biochemical methods also must be developed in concert to produce such systems in selectively labeled form. Here, we present 1H/13C-HSQC spectra of protonated methyl groups in a model system that mimics molecular weights up to ~560 kDa. Signals from side chain methyl groups of Ile, Leu, and Val residues are clearly detectable at correlation times up to ~330 ns. We have also developed a biochemical procedure to produce the 240 kDa, heteroheptameric Arp2/3 actin nucleation complex selectively labeled at one subunit and obtained 1H/13C-HSQC spectra of this assembly. Sensitivity in spectra of both the Arp2/3 complex and the model system indicate that methyl groups will be useful sources of information in nonsymmetric systems with molecular weights greater than 600 kDa at concentrations less than 100 μM. Methyl analyses will complement TROSY and CRINEPT analyses of amides in NMR studies of structure and molecular interactions of extremely large macromolecules and assemblies.
Assessment of thermal evolution stages and oil-gas migration of carbonate source rocks of early tertiary in eastern Sichuan, China, by organic inclusion analysis
Shi Jixi; Li Benchao; Fu Jiamo
The Jialinjiang Formation of early Tertiary in Sichuan, China, is a series of limestone and dolomite sediments deposited in a platform shoal environment. The diagenetic sequence and organic inclusions trapped in minerals of 95 samples from 20 drillings have been studied. At the late diagenetic stage, pale yellow organic inclusions consisted of liquid hydrocarbons disseminated in pore-infiltrating dolomite, and the homogeneous temperature of contemporaneous saline liquid inclusions possessing a low gas-liquid ratio was 86/degree/C. This indicates the evolution of the organic matter had gone over the oil generating threshold and oil formation had initiated. In the limestone formed at the late diagenetic stage, more brown-yellow organic inclusions were scattered and/or developed along with fissures, comprising 60-70% liquid hydrocarbons and 30-40% gaseous hydrocarbons. Contemporaneous saline liquid inclusions with gas-liquid ratios of 5-10% had homogeneous temperatures of 90/degree/-130/degree/C. These findings show that the organic material had entered a high evolution stage and oil migration had taken place on a large scale.
Factors controlling reservoir quality in tertiary sandstones and their significance to geopressured geothermal production. Annual report, May 1, 1979-May 31, 1980
Loucks, R.G.; Richmann, D.L.; Milliken, K.L.
Differing extents of diagenetic modification is the factor primarily responsible for contrasting regional reservoir quality of Tertiary sandstones from the Upper and Lower Texas Gulf Coast. Detailed comparison of Frio sandstones from the Chocolate Bayou/Danbury Dome area, Brazoria County, and Vicksburg sandstones from the McAllen Ranch Field area, Hidalgo County, reveals that extent of diagenetic modification is most strongly influenced by (1) detrital mineralogy and (2) regional geothermal gradients. Vicksburg sandstones from the McAllen Ranch Field area are less stable, chemically and mechanically, than Frio sandstones from the Chocolate Bayou/Danbury dome area. Vicksburg sandstones are mineralogically immature and contain greater proportions of feldspars and rock fragments than do Frio sandstones. Thr reactive detrital assemblage of Vicksubrg sandstones is highly susceptible to diagenetic modification. Susceptibility is enhanced by higher than normal geothermal gradients in the McAllen Ranch Field area. Thus, consolidation of Vicksburg sandstones began at shallower depth of burial and precipitation of authigenic phases (especially calcite) was more pervasive than in Frio sandstones. Moreover, the late-stage episode of ferroan calcite precipitation that occluded most secondary porosity in Vicksburg sandstones did not occur significantly in Frio sandstones. Therefore, regional reservoir quality of Frio sandstones from Brazoria County is far better than that characterizing Vicksburg sandstones from Hidalgo County, especially at depths suitable for geopressured geothermal energy production.
Photoimaging of the multiple filamentation of femtosecond laser pulses in poly(methyl methacrylate) doped with 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2-dioxaborine
Kulchin, Yu N; Vitrik, O B; Chekhlenok, A A; Zhizhchenko, A Yu; Proschenko, D Yu; Mirochnik, A G; Lyu Guohui
We have studied the filamentation of femtosecond laser pulses (? = 800 nm, ?42 fs pulse duration) in poly(methyl methacrylate) doped with 2,2-difluoro-4-(9-anthracyl)-6-methyl-1,3,2- dioxaborine and the associated photomodification of the material. The results demonstrate that multiple filamentation occurs at pulse energies above 5 ?J. At a pulse energy of 1.5 mJ, it is accompanied by supercontinuum generation. The average filament length in PMMA is 9 mm and the filament diameter is ?10 ?m. An incident power density of ?10{sup 12} W cm{sup -2} ensures inscription of the filament pattern owing to two-photon photochemical processes. Preliminary exposure to continuous light at ? = 400 nm enables an ordered filament pattern to be written. (interaction of laser radiation with matter)
Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite
Preda, N.; Rusen, E.; Musuc, A.; Enculescu, M.; Matei, E.; Marculescu, B.; Fruth, V.; Enculescu, I.
The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.
On the role of chemical reactions in initiating ultraviolet laser ablation in poly(methyl methacrylate)
Prasad, Manish; Conforti, Patrick F.; Garrison, Barbara J.
The role of chemical reactions is investigated versus the thermal and mechanical processes occurring in a polymer substrate during irradiation by a laser pulse and subsequent ablation. Molecular dynamics simulations with an embedded Monte Carlo based reaction scheme were used to study ultraviolet ablation of poly(methyl methacrylate) at 157 nm. We discuss the onset of ablation, the mechanisms leading to ablation, and the role of stress relaxation of the polymer matrix during ablation. Laser induced heating and chemical decomposition of the polymer substrate are considered as ablation pathways. It is shown that heating the substrate can set off ablation via mechanical failure of the material only for very short laser pulses. For longer pulses, the mechanism of ejection is thermally driven limited by the critical number of bonds broken in the substrate. Alternatively, if the photon energy goes towards direct bond breaking, it initiates chemical reactions, polymer unzipping, and formation of gaseous products, leading to a nearly complete decomposition of the top layers of substrates. The ejection of small molecules has a hollowing out effect on the weakly connected substrates which can lead to lift-off of larger chunks. Excessive pressure buildup upon the creation of gaseous molecules does not lead to enhanced yield. The larger clusters are thermally ejected, and an entrainment of larger polymer fragments in gaseous molecules is not observed.
Gamma-radiolytic stability of new methylated TODGA derivatives for minor actinide recycling
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Galan, Hitos; Zarzana, Christopher A.; Wilden, Andreas; Nunez, Ana; Schmidt, Holger; Egberink, Richard J. M.; Leoncini, Andrea; Cobos, Joaquin; Verboom, Willem; Modolo, Giuseppe; et al
The stability against gamma radiation of MeTODGA (methyl tetraoctyldiglycolamide) and Me2TODGA (dimethyl tetraoctyldiglycolamide), derivatives from the well-known extractant TODGA (N,N,N',N';-tetraoctyldiglycolamide), were studied and compared. Solutions of MeTODGA and Me2TODGA in alkane diluents were subjected to 60Co γ-irradiation in the presence and absence of nitric acid and analyzed using LC-MS to determine their rates of radiolytic concentration decrease, as well as to identify radiolysis products. The results of product identification from three different laboratories are compared and found to be in good agreement. The diglycolamide (DGA) concentrations decreased exponentially with increasing absorbed dose. The MeTODGA degradation rate constants (dose constants) weremore » uninfluenced by the presence of nitric acid, but the acid increased the rate of degradation for Me2TODGA. The degradation products formed by irradiation are also initially produced in greater amounts in acid-contacted solution, but products may also be degraded by continued radiolysis. As a result, the identified radiolysis products suggest that the weakest bonds are those in the diglycolamide center of these molecules.« less
Spin-symmetry conversion in methyl rotors induced by tunnel resonance at low temperature
Zhang, B.; Sun, C.; Horsewill, A. J.; Alsanoosi, A. M.; Aibout, A.
Field-cycling NMR in the solid state at low temperature (4.2 K) has been employed to measure the tunneling spectra of methyl (CH{sub 3}) rotors in phenylacetone and toluene. The phenomenon of tunnel resonance reveals anomalies in {sup 1}H magnetization from which the following tunnel frequencies have been determined: phenylacetone, ν{sub t} = 6.58 ± 0.08 MHz; toluene, ν{sub t(1)} = 6.45 ± 0.06 GHz and ν{sub t(2)} = 7.07 ± 0.06 GHz. The tunnel frequencies in the two samples differ by three orders of magnitude, meaning different experimental approaches are required. In phenylacetone the magnetization anomalies are observed when the tunnel frequency matches one or two times the {sup 1}H Larmor frequency. In toluene, doping with free radicals enables magnetization anomalies to be observed when the tunnel frequency is equal to the electron spin Larmor frequency. Cross-polarization processes between the tunneling and Zeeman systems are proposed and form the basis of a thermodynamic model to simulate the tunnel resonance spectra. These invoke space-spin interactions to drive the changes in nuclear spin-symmetry. The tunnel resonance lineshapes are explained, showing good quantitative agreement between experiment and simulations.
Electron Affinity of Phenyl-C61-Butyric Acid Methyl Ester (PCBM)
Larson, Bryon W.; Whitaker, James B.; Wang, Xue B.; Popov, Alexey A.; Rumbles, Garry; Kopidakis, Nikos; Strauss, Steven H.; Boltalina, Olga V.
The gas-phase electron affinity (EA) of phenyl-C61-butyric acid methyl ester (PCBM), one of the best-performing electron acceptors in organic photovoltaic devices, is measured by lowtemperature photoelectron spectroscopy for the first time. The obtained value of 2.63(1) eV is only ca. 0.05 eV lower than that of C60 (2.68(1) eV), compared to a 0.09 V difference in their E1/2 values measured in this work by cyclic voltammetry. Literature E(LUMO) values for PCBM that are typically estimated from cyclic voltammetry, and commonly used as a quantitative measure of acceptor properties, are dispersed over a wide range between -4.3 and -3.62 eV; the reasons for such a huge discrepancy are analyzed here, and the protocol for reliable and consistent estimations of relative fullerene-based acceptor strength in solution is proposed.
Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Modules: Preprint
Miller, D. C.; Gedvilas, L. M.; To, B.; Kennedy, C. E.; Kurtz, S. R.
Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate)(PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).
Phosphorylation and Methylation of Proteasomal Proteins of the Haloarcheon Haloferax volcanii
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Humbard, Matthew A.; Reuter, Christopher J.; Zuobi-Hasona, Kheir; Zhou, Guangyin; Maupin-Furlow, Julie A.
Promore » teasomes are composed of 20S core particles (CPs) of α - and β -type subunits that associate with regulatory particle AAA ATPases such as the proteasome-activating nucleotidase (PAN) complexes of archaea. In this study, the roles and additional sites of post-translational modification of proteasomes were investigated using the archaeon Haloferax volcanii as a model. Indicative of phosphorylation, phosphatase-sensitive isoforms of α 1 and α 2 were detected by 2-DE immunoblot. To map these and other potential sites of post-translational modification, proteasomes were purified and analyzed by tandem mass spectrometry (MS/MS). Using this approach, several phosphosites were mapped including α 1 Thr147, α 2 Thr13/Ser14 and PAN-A Ser340. Multiple methylation sites were also mapped to α 1 , thus, revealing a new type of proteasomal modification.bing the biological role of α 1 and PAN-A phosphorylation by site-directed mutagenesis revealed dominant negative phenotypes for cell viability and/or pigmentation for α 1 variants including Thr147Ala, Thr158Ala and Ser58Ala. An H. volcanii Rio1p Ser/Thr kinase homolog was purified and shown to catalyze autophosphorylation and phosphotransfer to α 1 . The α 1 variants in Thr and Ser residues that displayed dominant negative phenotypes were significantly reduced in their ability to accept phosphoryl groups from Rio1p, thus, providing an important link between cell physiology and proteasomal phosphorylation.« less
Phosphorylation and Methylation of Proteasomal Proteins of the HaloarcheonHaloferax volcanii
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Humbard, Matthew A.; Reuter, Christopher J.; Zuobi-Hasona, Kheir; Zhou, Guangyin; Maupin-Furlow, Julie A.
Proteasomes are composed of 20S core particles (CPs) of?- and?-type subunits that associate with regulatory particle AAA ATPases such as the proteasome-activating nucleotidase (PAN) complexes of archaea. In this study, the roles and additional sites of post-translational modification of proteasomes were investigated using the archaeonHaloferax volcaniias a model. Indicative of phosphorylation, phosphatase-sensitive isoforms of?1and?2were detected by 2-DE immunoblot. To map these and other potential sites of post-translational modification, proteasomes were purified and analyzed by tandem mass spectrometry (MS/MS). Using this approach, several phosphosites were mapped including?1Thr147,?2 Thr13/Ser14 and PAN-A Ser340. Multiple methylation sites were also mapped to?1, thus, revealing amore��new type of proteasomal modification. Probing the biological role of?1and PAN-A phosphorylation by site-directed mutagenesis revealed dominant negative phenotypes for cell viability and/or pigmentation for?1variants including Thr147Ala, Thr158Ala and Ser58Ala. AnH. volcaniiRio1p Ser/Thr kinase homolog was purified and shown to catalyze autophosphorylation and phosphotransfer to?1. The?1variants in Thr and Ser residues that displayed dominant negative phenotypes were significantly reduced in their ability to accept phosphoryl groups from Rio1p, thus, providing an important link between cell physiology and proteasomal phosphorylation.��less
Calcined Mg-Fe layered double hydroxide as an absorber for the removal of methyl orange
Peng, Chao; Dai, Jing; Yu, Jianying; Yin, Jian
In this work, methyl orange (MO) was effectively removed from aqueous solution with the calcined product of hydrothermal synthesized Mg/Fe layered double hydroxide (Mg/Fe-LDH). The structure, composition, morphology and textural properties of the Mg/Fe-LDH before and after adsorption were characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, nitrogen adsorption apparatus and X-ray photoelectron spectroscopy. It was confirmed that MO had been absorbed by calcined Mg/Fe-LDH which had strong interactions with MO. The adsorption of MO onto the Mg/Fe-LDH was systematically investigated by batch tests. The adsorption capacity of the Mg/Fe-LDH toward MO was found to be 194.9 mg • g{sup −1}. Adsorption kinetics and isotherm studies revealed that the adsorption of MO onto Mg/Fe-LDH was a spontaneous and endothermic process. These results indicate that Mg/Fe-LDH is a promising material for the removal of MO.
Trapping radiodine, in the form of methyl iodide, on nuclear carbon
Nacapricha, D.; Taylor, C.
Studies have been performed on potassium-iodide-impregnated charcoals of the type used in the nuclear industry for trapping radioiodine released during nuclear fission. The effects of various parameters on the trapping efficiency of methyl iodide have been investigated. A variation in particle size within a bulk charcoal caused poor precision in K value measurements because of differences in surface area, pore volume, and bed density, leading to differences in the deposition of the impregnant. Precision is improved by sieving the charcoal to a narrower size because smaller particles have a higher porosity. This finding is supported by surface area and pore measurements. Two methods of impregnation are compared by measuring K values and the deposition of potassium iodide. Charcoal impregnated by rotary evaporation exhibits both higher K values and higher potassium iodide contents than sprayed charcoal. Two designs of spraying drum are compared: a drum with helical vanes allows more efficient deposition and more uniform distribution of impregnant than a drum with axial vanes. A decrease in the K value with increasing humidity correlates with the available surface area. A similar correlation exists between water content and available pore volume. Aging of potassium-iodide-impregnated charcoal, caused by the formation of oxygen complexes on the surface, is associated with significant falls in K value. K values of charcoals also can be restored to at least their original values by heat treatment in the absence of air. 12 refs., 6 figs., 1 tab.
Detection of Methyl Salicylate Transforted by Honeybees (Apis mellifera) Using Solid Phase Microextration (SPME) Fibers
The ultimate goal of many environmental measurements is to determine the risk posed to humans or ecosystems by various contaminants. Conventional environmental monitoring typically requires extensive sampling grids covering several media including air, water, soil and vegetation. A far more efficient, innovative and inexpensive tactic has been found using honeybees as sampling mechanisms. Members from a single bee colony forage over large areas ({approx}2 x 10{sup 6} m{sup 2}), making tens of thousands of trips per day, and return to a fixed location where sampling can be conveniently conducted. The bees are in direct contact with the air, water, soil and vegetation where they encounter and collect any contaminants that are present in gaseous, liquid and particulate form. The monitoring of honeybees when they return to the hive provides a rapid method to assess chemical distributions and impacts (1). The primary goal of this technology is to evaluate the efficiency of the transport mechanism (honeybees) to the hive using preconcentrators to collect samples. Once the extent and nature of the contaminant exposure has been characterized, resources can be distributed and environmental monitoring designs efficiently directed to the most appropriate locations. Methyl salicylate, a chemical agent surrogate was used as the target compound in this study.
Synthesis of methyl methacrylate from coal-derived syngas: Quarterly report,, October 1-December 31, 1997
Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of three steps of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, Eastman developed two new processes which have resulted in two new invention reports. One process deals with carbonylation of benzyl ether which represents a model for coal liquefaction and the second focuses on the acceleration of carbonylation rates for propionic acid synthesis, via use of polar aprotic solvents. These two inventions are major improvements in the novel Mo-catalyzed homogeneous process for propionic acid synthesis technology, developed by Eastman. Over the last quarter, RTI completed three reaction cycles and two regeneration cycles as a part of long-term reaction regeneration cycle study on a 10% Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst, for vapor phase condensation reaction of formaldehyde with propionic acid.
Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models
Saeed, Noha M.; El-Demerdash, Ebtehal; Abdel-Rahman, Hanaa M.; Algandaby, Mardi M.; Al-Abbasi, Fahad A.; Abdel-Naim, Ashraf B.
Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-? (TNF-?) and interleukin-6 (IL-6). MP and EP decreased NF-?B expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ? Efficacy of MP and EP in combating inflammation was displayed in several models. ? MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ? MP and EP decreased TNF-? and IL-6 levels in experimental endotoxemia. ? MP and EP reduced NF-?B expression and histological changes in rat liver and lung. ? MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.
Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP) (Revised)
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification Laboratory Analytical Procedure (LAP) Issue Date: December 2, 2013 Revision Date: December 29, 2015 Stefanie Van Wychen, Kelsey Ramirez, and Lieve M.L. Laurens Technical Report NREL/TP-5100-60958 Revised December 2015 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from
This Week In Petroleum Printer-Friendly Version
Annual Energy Outlook [U.S. Energy Information Administration (EIA)]
this transition from Methyl Tertiary Butyl Ether (MTBE) reformulated gasoline (RFG) to ethanol RFG, since ethanol is not blended into the gasoline mixture until just before the...
Impact of Renewable Fuels Standard/MTBE Provisions of S. 517 Requested by Sens. Daschle & Murkowski
Reports and Publications (EIA)
Additional analysis of the impact of the Renewable Fuels Standard (RFS) and methyl tertiary butyl ether (MTBE) ban provisions of S. 517.
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Normal Butane Isobutane Other Liquids OxygenatesRenewables Oxygenates (excl. Fuel Ethanol) Methyl Tertiary Butyl Ether (MTBE) All Other Oxygenates Renewable Fuels (incl. Fuel Ethanol...
Refinery Stocks of Crude Oil and Petroleum Products
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Hydrocarbons Oxygenates (excl. Fuel Ethanol) Methyl Tertiary Butyl Ether (MTBE) All Other Oxygenates Renewable Fuels (incl. Fuel Ethanol) Fuel Ethanol Renewable Diesel Fuel Other ...
Motor Gasoline Market Spring 2007 and Implications for Spring...
Annual Energy Outlook [U.S. Energy Information Administration (EIA)]
began to decline, and with the transition from methyl tertiary butyl ether (MTBE) to ethanol completed and the end of the summer driving season drawing near, gasoline prices...
Gasoline and Diesel Fuel Update (EIA)
of "other" hydrocarbons and oxygenates include hydrogen and oxygenates especially fuel ethanol and methyl tertiary butyl ether (MTBE). The adjustment is equal to the...
Nonpremixed ignition, laminar flame propagation, and mechanism reduction of n-butanol, iso-butanol, and methyl butanoate
Lu, Wei; Kelley, A. P.; Law, C. K.
The non-premixed ignition temperature of n-butanol (CH{sub 3}CH{sub 2}CH{sub 2}CH{sub 2}OH), iso-butanol ((CH{sub 3}){sub 2}CHCH{sub 2}OH) and methyl butanoate (CH{sub 3}CH{sub 2}CH{sub 2}COOCH{sub 3}) was measured in a liquid pool assembly by heated oxidizer in a stagnation flow for system pressures of 1 and 3 atm. In addition, the stretch-corrected laminar flame speeds of mixtures of air�n-butanol/iso-butanol/methyl butanoate were determined from the outwardly propagating spherical flame at initial pressures of up to 2 atm, for an extensive range of equivalence ratio. The ignition temperature and laminar flame speeds of n-butanol and methyl butanoate were computationally simulated with three recently developed kinetic mechanisms in the literature. Dominant reaction pathways to ignition and flame propagation were identified and discussed through a chemical explosive mode analysis (CEMA) and sensitivity analysis. The detailed models were further reduced through a series of systematic strategies. The reduced mechanisms provided excellent agreement in both homogeneous and diffusive combustion environments and greatly improved the computation efficiency.
Phytoremediation of ionic and methyl mercury pollution. 1997 annual progress report
Meagher, R.B.
'The long-term goal of this research is to manipulate single-gene traits into plants, enabling them to process heavy metals and remediate heavy-metal pollution by resistance, sequestration, removal, and management of these contaminants (Meagher and Rugh, 1996; Meagher et al., 1997). The working hypothesis behind this proposal was that transgenic plants expressing both the bacterial organo mercury lyase (merB) and the mercuric ion reductase gene (merA) will (A) remove the mercury from polluted sites and (B) prevent methyl mercury from entering the food chain. The authors have had a very successful first year either testing aspects of this hypothesis directly or preparing material needed for future experiments. The results are outlined below under goals A and B, which are explicit in this hypothesis. There were less than 10% of the funds remaining in any category as projected in the first 12 month budget at the end of the first year, with the exception of the equipment category which had 25% of the funds remaining ({approximately} $8,000). Much of this remaining equipment money is being spent this week on a mercury vapor analyzer. It might be useful to remember that at the time this grant was awarded, the authors had successfully engineered a small model plant, Arabidopsis thalianat to use a highly modified bacterial mercuric ion reductase gene, merA9, to detoxify ionic mercury (Hg(II)), reducing it to Hg(0) (Rugh et al., 1996). Seeds from these plants germinate, grow, and set seed at normal growth rates on levels of Hg(II) that are lethal to normal plants. In assays on transgenic seedlings suspended in a solution of Hg(II), 10 ng of Hg(0) was evolved per min per mg wet weight of plant tissue. However, at that time, they had no information on expression of merA in any other plant species, nor had they expressed merB in any plant.'
Vapor phase tri-methyl-indium seeding system suitable for high temperature spectroscopy and thermometry
Whiddon, R.; Zhou, B.; Borggren, J.; Aldén, M.; Li, Z. S.
Tri-methyl-indium (TMI) is used as an indium transport molecule to introduce indium atoms to reactive hot gas flows/combustion environments for spectroscopic diagnostics. A seeding system was constructed to allow the addition of an inert TMI laden carrier gas into an air/fuel mixture burning consequently on a burner. The amount of the seeded TMI in the carrier gas can be readily varied by controlling the vapor pressure through the temperature of the container. The seeding process was calibrated using the fluorescent emission intensity from the indium 6{sup 2}S{sub 1/2} → 5{sup 2}P{sub 1/2} and 6{sup 2}S{sub 1/2} → 5{sup 2}P{sub 3/2} transitions as a function of the calculated TMI seeding concentration over a range of 2–45 ppm. The response was found to be linear over the range 3–22.5 ppm; at concentrations above 25 ppm there is a loss of linearity attributable to self-absorption or loss of saturation of TMI vapor pressure in the carrier gas flow. When TMI was introduced into a post-combustion environment via an inert carrier gas, molecular transition from InH and InOH radicals were observed in the flame emission spectrum. Combined laser-induced fluorescence and absorption spectroscopy were applied to detect indium atoms in the TMI seeded flame and the measured atomic indium concentration was found to be at the ppm level. This method of seeding organometallic vapor like TMI to a reactive gas flow demonstrates the feasibility for quantitative spectroscopic investigations that may be applicable in various fields, e.g., chemical vapor deposition applications or temperature measurement in flames with two-line atomic fluorescence.
Diffusional analysis of the adsorption of methyl iodide on silver exchanged mordenite
Jubin, R.T.; Counce, R.M.
The removal of organic iodides from off-gas streams is an important step in controlling the release of radioactive iodine to the environment during the treatment of radioactive wastes or the processing of some irradiated materials. Nine-well accepted mass transfer models were evaluated for their ability to adequately explain the observed CH{sub 3}I uptake behavior onto the Ag{degrees}Z. Linear and multidimensional regression techniques were used to estimate the diffusion constants and other model parameters, which then permitted the selection of an appropriate mass transfer model. Although a number of studies have been conducted to evaluate the loading of both elemental and methyl iodide on silver-exchanged mordenite, these studies focused primarily on the macro scale (deep bed) while evaluating the material under a broad range of process conditions and contaminants for total bed loading at the time of breakthrough. A few studies evaluated equilibrium or maximum loading. Thus, to date, only bulk loading data exist for the adsorption of CH{sub 3}I onto Ag{degrees}Z. Hence this is believed to be the first study to quantify the controlling mass transfer mechanisms of this process, It can be concluded from the analysis of the experimental data obtained by the {open_quotes}single-pellet{close_quotes} type experiments and for the process conditions used in this study that the overall mass transfer rate associated with the adsorption of CH{sub 3}I onto Ag{degrees}Z is affected by both micropore and macropore diffusion. The macropore diffusion rate was significantly faster than the micropore diffusion, resulting in a two-step adsorption behavior which was adequately modeled by a bimodal pore distribution model. The micropore diffusivity was determined to be on the order of 2 x 10{sup -14} cm{sup 2}/s. The system was also shown to be isothermal under all conditions of this study. 21 refs., 6 figs., 8 tabs.
Methyl chloride via oxyhydrochlorination of methane. Quarterly technical progress report No. 13, October--December 1994
The purpose of this contract is to develop a process for converting light alkane gases to methyl chloride via oxyhydrochlorination using highly selective, stable catalysts in fixed-bed reactors designed to remove the large amount of heat generated, so as to control the reaction temperature. Further, the objective is to obtain the engineering data base necessary for developing a commercially feasible process and to evaluate t economics of the process. Significant progress was made in six different technical areas during this quarter. These key highlights are: (1) Evaluation of catalyst samples from UCI led to the ordering of the OHC PDU catalyst batch. This catalyst batch arrived, was screened and found to be defective, and was reordered. (2) Natural gas containing higher hydrocarbons was used as a methane source. The reactant mixture formed oxygenates at temperatures lower than observed in the past. Burning at such low temperatures seems to create a product stream containing very little CH{sub 2}Cl{sub 2}. (3) Although it has not been decided if the PDU will use natural gas from the plant or methane or natural gas from cylinders as a methane feed source, it was concluded that an adsorption unit to remove sulfur and higher hydrocarbons is not necessary at this time. (4) PDU construction was completed in December. The bulk of insulation work was completed at the end of November. Much effort has been put into pressure testing the PDU`s systems. The startup team has become adept at finding and correcting such leaks. (5) SOP writing for the PDU was completed this quarter with communication with the software programmer to insure agreement between the software and SOP.
Methyl-parathion decreases sperm function and fertilization capacity after targeting spermatocytes and maturing spermatozoa
Pina-Guzman, Belem; Sanchez-Gutierrez, M.; Marchetti, Francesco; Hernandez-Ochoa, I.; Solis-Heredia, M.J .; Quintanilla-Vega, B.
Paternal germline exposure to organophosphorous pesticides (OP) has been associated with reproductive failures and adverse effects in the offspring. Methyl parathion (Me-Pa), a worldwide-used OP, has reproductive adverse effects and is genotoxic to sperm. Oxidative damage has been involved in the genotoxic and reproductive effects of OP. The purpose of this study was to determine the effects of Me-Pa on spermatozoa function and ability to fertilize. Male mice were exposed to Me-Pa (20 mg/kg bw, i.p.) and spermatozoa from epididymis-vas deferens were collected at 7 or 28 days post-treatment (dpt) to assess the effects on maturing spermatozoa and spermatocytes, respectively. DNA damage was evaluated by nick translation (NT-positive cells) and SCSA (percentDFI); lipoperoxidation (LPO) by malondialdehyde production; sperm function by spontaneous- and induced-acrosome reactions (AR); mitochondrial membrane potential (MMP) by using the JC-1 flurochrome; and, fertilization ability by an in vitro assay and in vivo mating. Results showed alterations in DNA integrity (percentDFI and NT-positive cells) at 7 and 28 dpt, in addition to decreased sperm quality and a decrease in induced-AR; reduced MMP and LPO was observed only at 7 dpt. We found negative correlations between LPO and all sperm alterations. Altered sperm functional parameters were associated with reduced fertilization rates at both times, evaluated either in vitro or in vivo. These results show that Me-Pa exposure of maturing spermatozoa and spermatocytes affects many sperm functional parameters that result in a decreased fertilizing capacity. Oxidative stress seems to be a likely mechanism ofthe detrimental effects of Me-Pa in male germ cells.
BIOENERGIZEME INFOGRAPHIC CHALLENGE: Tertiary Treatment
Office of Energy Efficiency and Renewable Energy (EERE)
This infographic was created by students from Nikola Tesla STEM High School in Redmond, WA, as part of the U.S. Department of Energy-BioenergizeME Infographic Challenge. The BioenergizeME...
Polymorphism of inflammatory genes and arsenic methylation capacity are associated with urothelial carcinoma
Wu, Chia-Chang; Huang, Yung-Kai; Chung, Chi-Jung; Huang, Chao-Yuan; Pu, Yeong-Shiau; Shiue, Horng-Sheng; Lai, Li-An; Lin, Ying-Chin; Su, Chien-Tien; Hsueh, Yu-Mei
Chronic exposure to arsenic can generate reactive oxidative species, which can induce certain proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-8 (IL-8). TNF-α, IL-6 and IL-8 have been shown to be involved in the development and progression of various cancers, including bladder cancer. This study aimed to investigate the joint effect of the polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C, IL-8 − 251 T/A and urinary arsenic profiles on urothelial carcinoma (UC) risk. This study evaluated 300 pathologically-confirmed cases of UC and 594 cancer-free controls. Urinary arsenic species were detected using high-performance liquid chromatography-linked hydride generator and atomic absorption spectrometry. The polymorphism of TNF-α − 308 G/A, IL-6 − 174 G/C and IL-8 − 251 T/A was determined using polymerase chain reaction-restriction fragment length polymorphism. The joint effects on UC risk were estimated by odds ratios and 95% confidence intervals using unconditional logistic regression. We found that the TNF-α − 308 A/A and IL-8 − 251 T/T polymorphisms were significantly associated with UC. Moreover, significant dose–response joint effect of TNF-α − 308 A/A or IL-8 − 251 T/T genotypes and arsenic methylation indices were seen to affect UC risk. The present results also showed a significant increase in UC risk in subjects with the IL-8 − 251 T/T genotype for each SD increase in urinary total arsenic and MMA%. In contrast, a significant decrease in UC risk was found in subjects who carried the IL-8 − 251 T/T genotype for each SD increase in DMA%. - Highlights: • Joint effect of the TNF-α -308 A/A genotype and urinary total arsenic affected UC. • Joint effect of the IL-8 -251 T/T genotype and urinary total arsenic affected UC. • Urinary total arsenic level, TNF-α -308 A/A and IL-8 -251 T/T genotype affected UC.
Photochemistry of Methyl Bromide on the α-Cr2O3(0001) Surface
Henderson, Michael A.
The photochemical properties of the Cr-terminated α-Cr2O3(0001) surface were explored using methyl bromide (CH3Br) as a probe molecule. CH3Br adsorbed and desorbed molecularly from the Cr-terminated α-Cr2O3(0001) surface without detectable thermal decomposition. Temperature programmed desorption (TPD) revealed a CH3Br desorption state at 240 K for coverages up to 0.5 ML, followed by more weakly bound molecules desorbing at 175 K for coverages up to 1 ML. Multilayer exposures led to desorption at ~130 K. The CH3Br sticking coefficient was unity at 105 K for coverages up to monolayer saturation, but decreased as the multilayer formed. In contrast, pre-oxidation of the surface (using an oxygen plasma source) led to capping of surface Cr3+ sites and near complete removal of CH3Br TPD states above 150 K. The photochemistry of chemisorbed CH3Br was explored on the Cr-terminated surface using post-irradiation TPD and photon stimulated desorption (PSD). Irradiation of adsorbed CH3Br with broad band light from a Hg arc lamp resulted in both photodesorption and photodecomposition of the parent molecule at a combined cross section of ~10-22 cm2. Parent PSD was indicative of molecular photodesorption, but CH3 was also detected in PSD and Br atoms were left on the surface, both reflective of photo-induced CH3-Br bond dissociation. Use of a 385 nm cut-off filter effectively shut down the photodissociation pathway but not the parent molecule photodesorption process. From these observations it is inferred that d-to-d transitions in α-Cr2O3, occurring at photon energies <3 eV, are not responsible for photodecomposition of 2 adsorbed CH3Br. It is unclear to what extent band-to-band versus direct CH3Br photolysis play in CH3-Br bond dissociation initiated by more energetic photons.
Methyl Formate Oxidation: Speciation Data, Laminar Burning Velocities, Ignition Delay Times and a Validated Chemical Kinetic Model
Dooley, S.; Burke, M. P.; Chaos, M.; Stein, Y.; Dryer, F. L.; Zhukov, V. P.; Finch, O.; Simmie, J. M.; Curran, H. J.
The oxidation of methyl formate (CH{sub 3}OCHO) has been studied in three experimental environments over a range of applied combustion relevant conditions: 1. A variable-pressure flow reactor has been used to quantify reactant, major intermediate and product species as a function of residence time at 3 atm and 0.5% fuel concentration for oxygen/fuel stoichiometries of 0.5, 1.0, and 1.5 at 900 K, and for pyrolysis at 975 K. 2. Shock tube ignition delays have been determined for CH{sub 3}OCHO/O{sub 2}/Ar mixtures at pressures of ? 2.7, 5.4, and 9.2 atm and temperatures of 1275�1935 K for mixture compositions of 0.5% fuel (at equivalence ratios of 1.0, 2.0, and 0.5) and 2.5% fuel (at an equivalence ratio of 1.0). 3. Laminar burning velocities of outwardly propagating spherical CH{sub 3}OCHO/air flames have been determined for stoichiometries ranging from 0.8�1.6, at atmospheric pressure using a pressure-release-type high-pressure chamber. A detailed chemical kinetic model has been constructed, validated against, and used to interpret these experimental data. The kinetic model shows that methyl formate oxidation proceeds through concerted elimination reactions, principally forming methanol and carbon monoxide as well as through bimolecular hydrogen abstraction reactions. The relative importance of elimination versus abstraction was found to depend on the particular environment. In general, methyl formate is consumed exclusively through molecular decomposition in shock tube environments, while at flow reactor and freely propagating premixed flame conditions, there is significant competition between hydrogen abstraction and concerted elimination channels. It is suspected that in diffusion flame configurations the elimination channels contribute more significantly than in premixed environments.
Using the apparent diffusion coefficient to identifying MGMT promoter methylation status early in glioblastoma: importance of analytical method
Rundle-Thiele, Dayle; Day, Bryan; Stringer, Brett; Fay, Michael; Martin, Jennifer; Jeffree, Rosalind L; Thomas, Paul; Bell, Christopher; Salvado, Olivier; Gal, Yaniv; Coulthard, Alan; Crozier, Stuart; Rose, Stephen
Accurate knowledge of O{sup 6}-methylguanine methyltransferase (MGMT) gene promoter subtype in patients with glioblastoma (GBM) is important for treatment. However, this test is not always available. Pre-operative diffusion MRI (dMRI) can be used to probe tumour biology using the apparent diffusion coefficient (ADC); however, its ability to act as a surrogate to predict MGMT status has shown mixed results. We investigated whether this was due to variations in the method used to analyse ADC. We undertook a retrospective study of 32 patients with GBM who had MGMT status measured. Matching pre-operative MRI data were used to calculate the ADC within contrast enhancing regions of tumour. The relationship between ADC and MGMT was examined using two published ADC methods. A strong trend between a measure of 'minimum ADC' and methylation status was seen. An elevated minimum ADC was more likely in the methylated compared to the unmethylated MGMT group (U = 56, P = 0.0561). In contrast, utilising a two-mixture model histogram approach, a significant reduction in mean measure of the 'low ADC' component within the histogram was associated with an MGMT promoter methylation subtype (P < 0.0246). This study shows that within the same patient cohort, the method selected to analyse ADC measures has a significant bearing on the use of that metric as a surrogate marker of MGMT status. Thus for dMRI data to be clinically useful, consistent methods of data analysis need to be established prior to establishing any relationship with genetic or epigenetic profiling.
Separation of Dimethyl Ether from Syn-Gas Components by Poly(dimethylsiloxane) and Poly(4-methyl-1-pentene) Membranes
Christopher J. Orme; Frederick F. Stewart
Permeability and selectivity in gas transport through poly(4-methyl-1-pentene) (TPX) and poly(dimethylsiloxane) (PDMS) using variable temperature mixed gas experiments is reported. Selected gases include H2, CO, CH4, CO2, and dimethyl ether (DME). The DME data is the first to be reported through these membranes. In this paper, the chosen polymers reflect both rubbery and crystalline materials. Rubbery polymers tend to be weakly size sieving, which, in this work, has resulted in larger permeabilities, lower separation factors, and lower activation energies of permeation (Ep). Conversely, the crystalline TPX membranes showed much greater sensitivity to penetrant size; although the gas condensability also played a role in transport.
Synthesis Of [2h, 13c]M [2h2m 13c], And [2h3,, 13c] Methyl Aryl Sulfones And Sulfoxides
Martinez, Rodolfo A.; Alvarez, Marc A.; Silks, III, Louis A.; Unkefer, Clifford J.; Schmidt, Jurgen G.
The present invention is directed to labeled compounds, [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfones and [.sup.2 H.sub.1, .sup.13 C], [.sup.2 H.sub.2, .sup.13 C] and [.sup.2 H.sub.3, .sup.13 C]methyl aryl sulfoxides, wherein the .sup.13 C methyl group attached to the sulfur of the sulfone or sulfoxide includes exactly one, two or three deuterium atoms and the aryl group is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently, hydrogen, a C.sub.1 -C.sub.4 lower alkyl, a halogen, an amino group from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each a C.sub.1 -C.sub.4 lower alkyl, a phenyl, or an alkoxy group. The present invention is also directed to processes of preparing methyl aryl sulfones and methyl aryl sulfoxides.
Placental oxidative stress and decreased global DNA methylation are corrected by copper in the Cohen diabetic rat
Ergaz, Zivanit; Guillemin, Claire; Neeman-azulay, Meytal; Weinstein-Fudim, Liza; Stodgell, Christopher J.; Miller, Richard K.; Szyf, Moshe; Ornoy, Asher
Fetal Growth Restriction (FGR) is a leading cause for long term morbidity. The Cohen diabetic sensitive rats (CDs), originating from Wistar, develop overt diabetes when fed high sucrose low copper diet (HSD) while the original outbred Sabra strain do not. HSD induced FGR and fetal oxidative stress, more prominent in the CDs, that was alleviated more effectively by copper than by the anti-oxidant vitamins C and E. Our aim was to evaluate the impact of copper or the anti-oxidant Tempol on placental size, protein content, oxidative stress, apoptosis and total DNA methylation. Animals were mated following one month of HSD or regular chow diet and supplemented throughout pregnancy with either 0, 1 or 2 ppm of copper sulfate or Tempol in their drinking water. Placental weight on the 21st day of pregnancy decreased in dams fed HSD and improved upon copper supplementation. Placental/fetal weight ratio increased among the CDs. Protein content decreased in Sabra but increased in CDs fed HSD. Oxidative stress biochemical markers improved upon copper supplementation; immunohistochemistry for oxidative stress markers was similar between strains and diets. Caspase 3 was positive in more placentae of dams fed HSD than those fed RD. Placental global DNA methylation was decreased only among the CDs dams fed HSD. We conclude that FGR in this model is associated with smaller placentae, reduced DNA placental methylation, and increased oxidative stress that normalized with copper supplementation. DNA hypomethylation makes our model a unique method for investigating genes associated with growth, oxidative stress, hypoxia and copper. - Highlights: • Sensitive Cohen diabetic rats (CDs) had small placentae and growth restricted fetuses. • CDs dams fed high sucrose low copper diet had placental global DNA hypomethylation. • Caspase 3 was positive in more placentae of dams fed HSD than those fed RD. • Oxidative stress parameters improved by Tempol and resolved by copper
Reactions of methyl groups on a non-reducible metal oxide: The reaction of iodomethane on stoichiometric α-Cr2O3(0001)
Dong, Yujung; Brooks, John D.; Chen, Tsung-Liang; Mullins, David R.; Cox, David F.
The reaction of iodomethane on the nearly stoichiometric α-Cr2O3(0001) surface produces gas phase ethylene, methane, and surface iodine adatoms. The reaction is first initiated by the dissociation of iodomethane into surface methyl fragments, -CH3, and iodine adatoms. Methyl fragments bound at surface Cr cation sites undergo a rate-limiting dehydrogenation reaction to methylene, =CH2. The methylene intermediates formed from methyl dehydrogenation can then undergo coupling reactions to produce ethylene via two principle reaction pathways: (1) direct coupling of methylene and (2) methylene insertion into the methyl surface bond to form surface ethyl groups which undergo β-H elimination to produce ethylene. The liberated hydrogen also combines with methyl groups to form methane. Iodine adatoms from the dissociation of iodomethane deactivate the surface by simple site blocking of the surface Cr3+ cations.
(E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol: X-ray and DFT-calculated structures
Kosar, B. Albayrak, C.; Odabasoglu, M.; Bueyuekguengoer, O.
The crystal structure of (E)-2-[(2-Bromophenylimino)methyl]-5-methoxyphenol is determined by using X-ray diffraction and then the molecular structure is investigated with density functional theory (DFT). X-Ray study shows that the title compound has a strong intramolecular O-H-N hydrogen bond and three dimensional crystal structure is primarily determined by C-H-{pi} and weak van der Waals interactions. The strong O-H-N bond is an evidence of the preference for the phenol-imine tautomeric form in the solid state. Optimized molecular geometry is calculated with DFT at the B3LYP/6-31G(d,p) level. The IR spectra of compound were recorded experimentally and calculated to compare with each other. The results from both experiment and theoretical calculations are compared in this study.
High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes
Chun, Young Tea; Chu, Daping; Neeves, Matthew; Placido, Frank; Smithwick, Quinn
High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiO{sub x} thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2?cm{sup 2}, exhibiting an optical contrast of 73.11% at the wavelength of 470?nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.
Differences in volatile methyl siloxane (VMS) profiles in biogas from landfills and anaerobic digesters and energetics of VMS transformations
Tansel, Berrin Surita, Sharon C.
Highlights: • In the digester gas, D4 and D5 comprised the 62% and 27% if siloxanes, respectively. • In landfill gas, the bulk of siloxanes were TMSOH (58%) followed by D4 (17%). • Methane utilization may be a possible mechanism for TMSOH formation in the landfills. • The geometric configurations of D4 and D5 molecules make them very stable. - Abstract: The objectives of this study were to compare the types and levels of volatile methyl siloxanes (VMS) present in biogas generated in the anaerobic digesters and landfills, evaluate the energetics of siloxane transformations under anaerobic conditions, compare the conditions in anaerobic digesters and municipal solid waste (MSW) landfills which result in differences in siloxane compositions. Biogas samples were collected at the South District Wastewater Treatment Plant and South Dade Landfill in Miami, Florida. In the digester gas, D4 and D5 comprised the bulk of total siloxanes (62% and 27%, respectively) whereas in the landfill gas, the bulk of siloxanes were trimethylsilanol (TMSOH) (58%) followed by D4 (17%). Presence of high levels of TMSOH in the landfill gas indicates that methane utilization may be a possible reaction mechanism for TMSOH formation. The free energy change for transformation of D5 and D4 to TMSOH either by hydrogen or methane utilization are thermodynamically favorable. Either hydrogen or methane should be present at relatively high concentrations for TMSOH formation which explains the high levels present in the landfill gas. The high bond energy and bond distance of the Si–O bond, in view of the atomic sizes of Si and O atoms, indicate that Si atoms can provide a barrier, making it difficult to break the Si–O bonds especially for molecules with specific geometric configurations such as D4 and D5 where oxygen atoms are positioned inside the frame formed by the large Si atoms which are surrounded by the methyl groups.
Design of highly ordered Ag-SrTiO{sub 3} nanotube arrays for photocatalytic degradation of methyl orange
Sun Yue; Liu Jiawen; Li Zhonghua
Ag-SrTiO{sub 3} nanotube arrays were successfully prepared for the degradation of methyl orange (MO) under ultraviolet irradiation. In order to form highly ordered SrTiO{sub 3} nanotube arrays, the preparation of TiO{sub 2} nanotube arrays by anodic oxidation of titanium foil in different electrolytes was investigated. The selected organic solvents in electrolytes include glycerol, dimethyl sulfoxide and glycol. The results indicate that the morphology of TiO{sub 2} nanotube arrays prepared in glycol containing ammonium fluoride electrolyte is more regular. Then SrTiO{sub 3} nanotube arrays were synthesized by a hydrothermal method using TiO{sub 2} nanotube arrays as the precursor. In order to further improve the photocatalytic activity of SrTiO{sub 3} nanotube arrays, Ag nanoparticles were loaded on SrTiO{sub 3} nanotube arrays by two sets of experiments. The loaded Ag results in an enhancement of photocatalytic activity of SrTiO{sub 3} nanotube arrays. Moreover, the effect of pH on the photocatalytic degradation of MO was also studied. - Graphical abstract: Ag-SrTiO{sub 3} nanotube arrays were successfully prepared. The photocatalytic activity was evaluated by degradation of methyl orange under ultraviolet irradiation. Highlights: > TiO{sub 2} nanotube arrays prepared in glycol+NH{sub 4}F electrolyte are more regular. > Highly ordered Ag-SrTiO{sub 3} nanotube arrays were successfully synthesized. > Ag loading could enhance the photocatalytic activity of SrTiO{sub 3} nanotube arrays. > Ag-SrTiO{sub 3} nanotube arrays show excellent catalytic activity at a low pH value.
Sub-5 nm Domains in Ordered Poly(cyclohexylethylene)-block-poly(methyl methacrylate) Block Polymers for Lithography.
Kennemur, Justin; Yao, Li; Bates, Frank Stephen; Hillmyer, Marc
A series of poly(cyclohexylethylene)-block-poly- (methyl methacrylate) (PCHE PMMA) diblock copolymers with varying molar mass (4.9 kg/mol Mn 30.6 kg/mol) and narrow molar mass distribution were synthesized through a combination of anionic and atom transfer radical polymerization (ATRP) techniques. Heterogeneous catalytic hydrogenation of -(hydroxy)polystyrene (PS-OH) yielded -(hydroxy)poly(cyclohexylethylene) (PCHEOH) with little loss of hydroxyl functionality. PCHE-OH was reacted with -bromoisobutyryl bromide (BiBB) to produce an ATRP macroinitiator used for the polymerization of methyl methacrylate. PCHE PMMA is a glassy, thermally stable material with a large effective segment segment interaction parameter, eff = (144.4 6.2)/T (0.162 0.013), determined by meanfield analysis of order-to-disorder transition temperatures (TODT) measured by dynamic mechanical analysis and differential scanning calorimetry. Ordered lamellar domain pitches (9 D 33 nm) were identified by small-angle X-ray scattering from neat BCPs containing 43 52 vol % PCHE ( f PCHE). Atomic force microscopy was used to show 7.5 nm lamellar features (D = 14.8 nm) which are some of the smallest observed to date. The lowest molar mass sample (Mn = 4.9 kg/mol, f PCHE = 0.46) is characterized by TODT = 173 3 C and sub-5 nm nanodomains, which together with the sacrificial properties of PMMA and the high overall thermal stability place this material at the forefront of high- systems for advanced nanopatterning applications.
Supramolecular organization of calix[4]pyrrole with a methyl-trialkylammonium anion exchanger leads to remarkable reversal of selectivity for sulfate extraction vs. nitrate
Borman, Christopher J; Custelcean, Radu; Hay, Benjamin; Bill, Nathan; Sessler, Jonathan L.; Moyer, Bruce A
meso-Octamethylcalix[4]pyrrole (C4P) enhances sulfate selectivity in solvent extraction by Aliquat 336N, an effect ascribed to the supramolecular preorganization and thermodynamic stability imparted by insertion of the methyl group of the Aliquat cation into the cup of C4P in its cone conformation.
On the Dissociation of Methyl Orange: Spectrophotometric Investigation in Aqueous Solutions from 10 to 90ºC and Theoretical Evidence for Intramolecular Dihydrogen Bonding
Boily, Jean F.; Seward, Terry M.
The dissociation of methyl orange was investigated by spectrophotometry in aqueous solutions from 10 to 90°C and by quantum chemical calculations. Combined chemometric and thermodynamic analyses of the spectrophotometric data were used to simultaneously extract the thermodynamic stabilities and the spectrophotometric attributes of the dominant methyl orange species in solutions containing less than 20.00 mmol kg-1 perchloric acid and submicromolal concentrations of methyl orange. The analyses revealed the presence of only one monomeric deprotonated and one monomeric protonated species. The spectra did not reveal any evidence for the presence of tautomeric equilibria between the protonated azo and ammonium species in the experimental range studied. Thermodynamic analyses of the temperature dependent dissociation constants showed the reactions to be endothermic and enthalpy driven reaction with increasing acidity and increasing temperature. All molar absorption coefficients in the 275-375 nm range can be adequately reproduced in the 10-90°C range with a set of Gauss-Lorentz parameters and used to predict the absorption spectra for any desired condition. The dominant features of the spectrophotometric attributes of the methyl orange species could also be retrieved in Time Dependent-Density Functional Theory (TD-DFT) calculations. Topological analyses of the electron density also revealed the formation of a dihydrogen bond between the azo proton and an adjacent phenyl ring hydridic hydrogen which increases the stability of the azo molecules relative to the ammonium molecule.
Global Proteome Response to Deletion of Genes Related to Mercury Methylation and Dissimilatory Metal Reduction Reveals Changes in Respiratory Metabolism in Geobacter sulfurreducens PCA
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Qian, Chen; Johs, Alexander; Chen, Hongmei; Mann, Benjamin F.; Lu, Xia; Abraham, Paul E.; Hettich, Robert L.; Gu, Baohua
Geobacter sulfurreducens PCA can reduce, sorb, and methylate mercury (Hg); however, the underlying biochemical mechanisms of these processes and interdependent metabolic pathways remain unknown. In this study, shotgun proteomics was used to compare global proteome profiles between wild-type G. sulfurreducens PCA and two mutant strains: a ΔhgcAB mutant, which is deficient in two genes known to be essential for Hg methylation and a ΔomcBESTZ mutant, which is deficient in five outer membrane c-type cytochromes and thus impaired in its ability for dissimilatory metal ion reduction. We were able to delineate the global response of G. sulfurreducens PCA in both mutantsmore » and identify cellular networks and metabolic pathways that were affected by the loss of these genes. Deletion of hgcAB increased the relative abundances of proteins implicated in extracellular electron transfer, including most of the c-type cytochromes, PilA-C, and OmpB, and is consistent with a previously observed increase in Hg reduction in the hgcAB mutant. Deletion of omcBESTZ was found to significantly increase relative abundances of various methyltransferases, suggesting that a loss of dissimilatory reduction capacity results in elevated activity among one-carbon metabolic pathways and thus increased methylation. We show that G. sulfurreducens PCA encodes only the folate branch of the Wood Ljungdahl pathway, and proteins associated with the folate branch were found at lower abundance in the ΔhgcAB mutant strain than the wild type. In conclusion, this observation supports the hypothesis that the function of HgcA and HgcB may be linked to one carbon metabolism through the folate branch of the Wood-Ljungdahl pathway by providing methyl groups required for Hg methylation.« less
Role for DNA methylation in the regulation of miR-200c and miR-141 expression in normal and cancer cells
Vrba, Lukas; Jensen, Taylor J.; Garbe, James C.; Heimark, Ronald L.; Cress, Anne E.; Dickinson, Sally; Stampfer, Martha R.; Futscher, Bernard W.
BACKGROUND: The microRNA-200 family participates in the maintenance of an epithelial phenotype and loss of its expression can result in epithelial to mesenchymal transition (EMT). Furthermore, the loss of expression of miR-200 family members is linked to an aggressive cancer phenotype. Regulation of the miR-200 family expression in normal and cancer cells is not fully understood. METHODOLOGY/ PRINCIPAL FINDINGS: Epigenetic mechanisms participate in the control of miR-200c and miR-141 expression in both normal and cancer cells. A CpG island near the predicted mir-200c/mir-141 transcription start site shows a striking correlation between miR-200c and miR-141 expression and DNA methylation in both normal and cancer cells, as determined by MassARRAY technology. The CpG island is unmethylated in human miR-200/miR-141 expressing epithelial cells and in miR-200c/miR-141 positive tumor cells. The CpG island is heavily methylated in human miR-200c/miR-141 negative fibroblasts and miR-200c/miR-141 negative tumor cells. Mouse cells show a similar inverse correlation between DNA methylation and miR-200c expression. Enrichment of permissive histone modifications, H3 acetylation and H3K4 trimethylation, is seen in normal miR-200c/miR-141-positive epithelial cells, as determined by chromatin immunoprecipitation coupled to real-time PCR. In contrast, repressive H3K9 dimethylation marks are present in normal miR-200c/miR-141-negative fibroblasts and miR-200c/miR-141 negative cancer cells and the permissive histone modifications are absent. The epigenetic modifier drug, 5-aza-2'-deoxycytidine, reactivates miR-200c/miR-141 expression showing that epigenetic mechanisms play a functional role in their transcriptional control. CONCLUSIONS/ SIGNIFICANCE: We report that DNA methylation plays a role in the normal cell type-specific expression of miR-200c and miR-141 and this role appears evolutionarily conserved, since similar results were obtained in mouse. Aberrant DNA methylation of the
Gestational exposure to diethylstilbestrol alters cardiac structure/function, protein expression and DNA methylation in adult male mice progeny
Haddad, Rami, E-mail: firstname.lastname@example.com [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada) [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada); Division of Experimental Medicine, Department of Medicine, McGill University, 850 Sherbrooke Street, Montr�al, Qu�bec, Canada H3A 1A2 (Canada); Kasneci, Amanda, E-mail: email@example.com [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada)] [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada); Mepham, Kathryn, E-mail: email@example.com [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada) [Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada); Division of Experimental Medicine, Department of Medicine, McGill University, 850 Sherbrooke Street, Montr�al, Qu�bec, Canada H3A 1A2 (Canada); Sebag, Igal A., E-mail: firstname.lastname@example.com [Division of Cardiology, Jewish General Hospital, 3755 chemin Cote Ste Catherine, Montr�al, Qu�bec, Canada H3T 1E2 (Canada); and others
Pregnant women, and thus their fetuses, are exposed to many endocrine disruptor compounds (EDCs). Fetal cardiomyocytes express sex hormone receptors making them potentially susceptible to re-programming by estrogenizing EDCs. Diethylstilbestrol (DES) is a proto-typical, non-steroidal estrogen. We hypothesized that changes in adult cardiac structure/function after gestational exposure to the test compound DES would be a proof in principle for the possibility of estrogenizing environmental EDCs to also alter the fetal heart. Vehicle (peanut oil) or DES (0.1, 1.0 and 10.0 ?g/kg/da.) was orally delivered to pregnant C57bl/6n dams on gestation days 11.5�14.5. At 3 months, male progeny were left sedentary or were swim trained for 4 weeks. Echocardiography of isoflurane anesthetized mice revealed similar cardiac structure/function in all sedentary mice, but evidence of systolic dysfunction and increased diastolic relaxation after swim training at higher DES doses. The calcium homeostasis proteins, SERCA2a, phospholamban, phospho-serine 16 phospholamban and calsequestrin 2, are important for cardiac contraction and relaxation. Immunoblot analyses of ventricle homogenates showed increased expression of SERCA2a and calsequestrin 2 in DES mice and greater molecular remodeling of these proteins and phospho-serine 16 phospholamban in swim trained DES mice. DES increased cardiac DNA methyltransferase 3a expression and DNA methylation in the CpG island within the calsequestrin 2 promoter in heart. Thus, gestational DES epigenetically altered ventricular DNA, altered cardiac function and expression, and reduced the ability of adult progeny to cardiac remodel when physically challenged. We conclude that gestational exposure to estrogenizing EDCs may impact cardiac structure/function in adult males. -- Highlights: ? Gestational DES changes cardiac SERCA2a and CASQ2 expression. ? Echocardiography identified systolic dysfunction and increased diastolic relaxation. ? DES increased DNMT
Hydrothermal synthesis of Mn vanadate nanosheets and visible-light photocatalytic performance for the degradation of methyl blue
Pei, L.Z. Xie, Y.K.; Pei, Y.Q.; Jiang, Y.X.; Yu, H.Y.; Cai, Z.Y.
Graphical abstract: - Highlights: � Mn vanadate nanosheets have been synthesized by simple hydrothermal process. � The formation of Mn vanadate nanosheets can be controlled by growth conditions. � Mn vanadate nanosheets exhibit good photocatalytic activities for methyl blue. - Abstract: Mn vanadate nanosheets have been synthesized via a facile hydrothermal route using ammonium metavanadate and Mn acetate as the raw materials, polyvinyl pyrrolidone (PVP) as the surfactant. X-ray diffraction (XRD) shows that the Mn vanadate nanosheets are composed of monoclinic MnV{sub 2}O{sub 6} phase. Scanning electron microscopy (SEM) observation indicates that the nanosheets have the average thickness of about 50 nm, length of 2�10 ?m and width of 800 nm to 2 ?m. The growth process of the Mn vanadate nanosheets has also been discussed based on the analysis of the roles of the growth conditions on the formation of the Mn vanadate nanosheets. The nanosheets show good photocatalytic activities for the degradation of methylene blue (MB) under visible light irradiation. About 72.96% MB can be degraded after visible light irradiation for 1 h over 10 mg Mn vanadate nanosheets in 10 mL MB solution with the concentration of 10 mg L{sup ?1}.
Studies on the binding of 5-N-methylated quindoline derivative to human telomeric G-quadruplex
Xu, Wei; Tan, Jia-Heng; Chen, Shuo-Bin; Hou, Jin-Qiang; Li, Ding; Huang, Zhi-Shu; Gu, Lian-Quan
Research highlights: {yields} Hydrophobic interaction provided an important driving force for the interaction between ligand and G-quadruplex. {yields} Constrained water molecules were released from surface of G-tetrad upon the formation of the complex. {yields} The end-stacking mode for quindoline derivative was validated through UV-vis, ITC, steady-state, and time-resolved fluorescence experiment. {yields} The binding of compound 1 to quadruplex was found to be a temperature-dependent and enthalpy-entropy compensation process. -- Abstract: Quindoline derivatives as telomeric quadruplex ligands have shown good biological activity for telomerase inhibition. In the present study, we used spectroscopic and calorimetric methods to investigate the interactions between a quindoline derivative (5-methyl-11-(2-morpholinoethylamino)-10-H-indolo-[3,2-b]quinolin-5-ium iodide, compound 1) and human telomeric G-quadruplex. The thermodynamic studies using isothermal titration calorimetry (ITC) indicated that their binding process was temperature-dependent and enthalpy-entropy co-driven. The significant negative heat capacity was obtained experimentally from the temperature dependence of enthalpy changes, which was consistent with that from theoretical calculation, and all suggesting significant hydrophobic contribution to the molecular recognition process. Based on the results from UV-vis, ITC, steady-state and time-resolved fluorescence, their binding mode was determined as two ligand molecules stacking on the quartets on both ends of the quadruplex. These results shed light on rational design and development of quindoline derivatives as G-quadruplex binding ligands.
Effects of Turbulence on the Combustion Properties of Partially Premixed Flames of Canola Methyl Ester and Diesel Blends
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Dhamale, N.; Parthasarathy, R. N.; Gollahalli, S. R.
Canola methyl ester (CME) is a biofuel that is a renewable alternative energy resource and is produced by the transesterification of canola oil. The objective of this study was to document the effects of turbulence on the combustion characteristics of blends of CME and No 2 diesel fuel in a partially-premixed flame environment. The experiments were conducted with mixtures of pre-vaporized fuel and air at an initial equivalence ratio of 7 and three burner exit Reynolds numbers, 2700, 3600, and 4500. Three blends with 25, 50, and 75% volume concentration of CME were studied. The soot volume fraction was highestmore » for the pure diesel flames and did not change significantly with Reynolds number due to the mutually compensating effects of increased carbon input rate and increased air entrainment as the Reynolds number was increased. The global NOx emission index was highest and the CO emission index was the lowest for the pure CME flame, and varied non-monotonically with biofuel content in the blend The mean temperature and the NOx concentration at three-quarter flame height were generally correlated, indicating that the thermal mechanism of NOx formation was dominant in the turbulent biofuel flames also.« less
Photocatalytic degradation of methyl orange dye in water solutions in the presence of MWCNT/TiO{sub 2} composites
Da Dalt, S.; Alves, A.K.; Bergmann, C.P.
Highlights: ? MWCNTs/TiO{sub 2} composites were obtained to degrade organic dyes in water. ? MWCNT/TiO{sub 2} composites were analyzed by photocatalysis and structural characterization. ? The photocatalytic shows efficient method for the degradation of dyes from aqueous effluents. - Abstract: The textile and dyestuff industries are the primary sources of the release of synthetic dyes into the environment and usually there are major pollutants in dye wastewaters. Because of their toxicity and slow degradation, these dyes are categorized as environmentally hazardous materials. In this context, carbon nanotubes/TiO{sub 2} (CNTs/TiO{sub 2}) composites were prepared using multi-walled CNTs (MWCNTs), titanium (IV) propoxide and commercial TiO{sub 2} (P25{sup �}) as titanium oxide sources, to degrade the methyl orange dye in solution through photocatalyst activity using UV irradiation. The composites were prepared by solution processing followed by thermal treatment at 400, 500 and 600 �C. The heterojunction between nanotubes and TiO{sub 2} was confirmed by XRD, specific surface area. The coating morphology was observed with SEM and TEM.
Synthesis of 6-Methyl-9-n-propyldibenzothiophene-4-ol. Quarterly technical progress report No. 5, July 28--October 28, 1991
Not Available
The material presented here has been described to some extent in Status Reports 12, 13, and 14 and covers the progress toward the synthesis of the modified target molecules 9-isopropyl-4-methoxy-6-methyldibenzothiophene (13) and 9-isopropyl-6-methyldibenzothiophene-4-ol (14). It is divided into three parts: (a) Dehydrogenation experiments On tetrahydrodibenzothiophene 12. (b) methoxyl methyl cleavage of 13 to 14 using boron tribromide. (c) isolation and purification of methoxydibenzothiophene 13.
The Vital Function of Fe3O4@Au nanocomposites for Hydrolase Biosensor Design and Its Application in Detection of Methyl Parathion
Zhao, Yuting; Zhang, Weiying; Lin, Yuehe; Du, Dan
A nanocomposite of gold nanoparticles (AuNPs) decorating a magnetic Fe3O4 core was synthesized using cysteamine (SH�NH2) as linker, and characterized by TEM, XPS, UV and electrochemistry. Then a hydrolase biosensor, based on self-assembly of methyl parathion hydrolase (MPH) on the Fe3O4@Au nanocomposite, was developed for sensitive and selective detection of the organophosphorus pesticide (OP) methyl parathion. The magnetic nanocomposite provides an easy way to construct the enzyme biosensor by simply exerting an external magnetic field, and also provides a simple way to renew the electrode surface by removing the magnet. Unlike inhibition-based enzyme biosensors, the hydrolase is not poisoned by OPs and thus is reusable for continuous measurement. AuNPs not only provide a large surface area, high loading efficiency and fast electron transfer, but also stabilize the enzyme through electrostatic interactions. The MPH biosensor shows rapid response and high selectivity for detection of methyl parathion, with a linear range from 0.5 to 1000 ng/mL and a detection limit of 0.1 ng/mL. It also shows acceptable reproducibility and stability. The simplicity and ease of operation of the proposed method has great potential for on-site detection of P�S containing pesticides and provides a promising strategy to construct a robust biosensor.
This report provides a detailed account of a two year chronic inhalation study of methyl bromide toxicity in B6C3Fl mice conducted for the National Toxicology Program. Mice were randomized into three dose groups (10, 33 and 100 ppm methyl bromide) and one control group (0 ppm) per sex and exposed 5 days/week, 6 hours/day, for a total of 103 weeks. Endpoints included body weight; clinical signs and mortality, and at 6, 15 and 24 months of exposure, animals were sacrificed for organ weights, hematology and histopathology. In addition, a subgroup of animals in each dosage group was monitored for neurobehavioral and neuropathological changes. After only 20 weeks of exposure, 48% of the males and 12% of the females in the 100 ppm group had died. Exposures were terminated in that group and the surviving mice were observed for the duration of the study. Exposure of B6C3Fl mice to methyl bromide, even for only 20 weeks, produced significant changes in growth rate, mortality, organ weights and neurobehavioral functioning. These changes occurred in both males and females, but were more pronounced in males.
Structural and biochemical insights into 2′-O-methylation at the 3′-terminal nucleotide of RNA by Hen1
Chan, Chio Mui; Zhou, Chun; Brunzelle, Joseph S.; Huang, Raven H.
Small RNAs of {approx}20-30 nt have diverse and important biological roles in eukaryotic organisms. After being generated by Dicer or Piwi proteins, all small RNAs in plants and a subset of small RNAs in animals are further modified at their 3'-terminal nucleotides via 2'-O-methylation, carried out by the S-adenosylmethionine-dependent methyltransferase (MTase) Hen1. Methylation at the 3' terminus is vital for biological functions of these small RNAs. Here, we report four crystal structures of the MTase domain of a bacterial homolog of Hen1 from Clostridium thermocellum and Anabaena variabilis, which are enzymatically indistinguishable from the eukaryotic Hen1 in their ability to methylate small single-stranded RNAs. The structures reveal that, in addition to the core fold of the MTase domain shared by other RNA and DNA MTases, the MTase domain of Hen1 possesses a motif and a domain that are highly conserved and are unique to Hen1. The unique motif and domain are likely to be involved in RNA substrate recognition and catalysis. The structures allowed us to construct a docking model of an RNA substrate bound to the MTase domain of bacterial Hen1, which is likely similar to that of the eukaryotic counterpart. The model, supported by mutational studies, provides insight into RNA substrate specificity and catalytic mechanism of Hen1.
Structures of Escherichia coli DNA adenine methyltransferase (Dam) in complex with a non-GATC sequence: Potential implications for methylation-independent transcriptional repression
Horton, John R.; Zhang, Xing; Blumenthal, Robert M.; Cheng, Xiaodong
DNA adenine methyltransferase (Dam) is widespread and conserved among the γ-proteobacteria. Methylation of the Ade in GATC sequences regulates diverse bacterial cell functions, including gene expression, mismatch repair and chromosome replication. Dam also controls virulence in many pathogenic Gram-negative bacteria. An unexplained and perplexing observation about Escherichia coli Dam (EcoDam) is that there is no obvious relationship between the genes that are transcriptionally responsive to Dam and the promoter-proximal presence of GATC sequences. Here, we demonstrate that EcoDam interacts with a 5-base pair non-cognate sequence distinct from GATC. The crystal structure of a non-cognate complex allowed us to identify a DNA binding element, GTYTA/TARAC (where Y = C/T and R = A/G). This element immediately flanks GATC sites in some Dam-regulated promoters, including the Pap operon which specifies pyelonephritis-associated pili. In addition, Dam interacts with near-cognate GATC sequences (i.e. 3/4-site ATC and GAT). All together, these results imply that Dam, in addition to being responsible for GATC methylation, could also function as a methylation-independent transcriptional repressor.
Structures of Escherichia coli DNA adenine methyltransferase (Dam) in complex with a non-GATC sequence: Potential implications for methylation-independent transcriptional repression
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Horton, John R.; Zhang, Xing; Blumenthal, Robert M.; Cheng, Xiaodong
DNA adenine methyltransferase (Dam) is widespread and conserved among the γ-proteobacteria. Methylation of the Ade in GATC sequences regulates diverse bacterial cell functions, including gene expression, mismatch repair and chromosome replication. Dam also controls virulence in many pathogenic Gram-negative bacteria. An unexplained and perplexing observation about Escherichia coli Dam (EcoDam) is that there is no obvious relationship between the genes that are transcriptionally responsive to Dam and the promoter-proximal presence of GATC sequences. Here, we demonstrate that EcoDam interacts with a 5-base pair non-cognate sequence distinct from GATC. The crystal structure of a non-cognate complex allowed us to identify amore » DNA binding element, GTYTA/TARAC (where Y = C/T and R = A/G). This element immediately flanks GATC sites in some Dam-regulated promoters, including the Pap operon which specifies pyelonephritis-associated pili. In addition, Dam interacts with near-cognate GATC sequences (i.e. 3/4-site ATC and GAT). All together, these results imply that Dam, in addition to being responsible for GATC methylation, could also function as a methylation-independent transcriptional repressor.« less
Sol�gel auto combustion synthesis of CoFe{sub 2}O{sub 4}/1-methyl-2-pyrrolidone nanocomposite with ethylene glycol: Its magnetic characterization
Topkaya, R.; Kurtan, U.; Junejo, Y.; Baykal, A.
Graphical abstract: - Highlights: � CoFe{sub 2}O{sub 4} was generated by sol�gel autocombustion using 1-methyl-2-pyrrolidone and ethylene glycol. � The presence of spin-disordered surface layer on magnetic core was established. � A linear dependence of the coercivity on temperature was fitted to Kneller's law. - Abstract: Magnetic nanoparticles were generated by sol�gel auto combustion synthesis of metal salts in the presence of 1-methyl-2-pyrrolidone, a functional solvent and ethylene glycol as usual solvent. The average crystallite size was obtained by using line profile fitting as 11 � 5 nm. The saturation magnetization value decreases with usage of the ethylene glycol in synthesis. The observed exchange bias effect further confirms the existence of the magnetically ordered core surrounded by spin-disordered surface layer and the ethylene glycol. Square-root temperature dependence of coercivity can be fitted to Kneller's law in the temperature range of 10�400 K. The reduced remanent magnetization values lower than the theoretical value of 0.5 for non-interacting single domain particles indicate the CoFe{sub 2}O{sub 4}-1-methyl-2-pyrrolidone nanocomposite to have uniaxial anisotropy instead of the expected cubic anisotropy according to the Stoner�Wohlfarth model.
{sup 13}C-METHYL FORMATE: OBSERVATIONS OF A SAMPLE OF HIGH-MASS STAR-FORMING REGIONS INCLUDING ORION-KL AND SPECTROSCOPIC CHARACTERIZATION
Favre, C�cile; Bergin, Edwin A.; Crockett, Nathan R.; Neill, Justin L.; Carvajal, Miguel; Field, David; J�rgensen, Jes K.; Bisschop, Suzanne E.; Brouillet, Nathalie; Despois, Didier; Baudry, Alain; Kleiner, Isabelle; Margul�s, Laurent; Huet, Th�r�se R.; Demaison, Jean E-mail: firstname.lastname@example.com
We have surveyed a sample of massive star-forming regions located over a range of distances from the Galactic center for methyl formate, HCOOCH{sub 3}, and its isotopologues H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3}. The observations were carried out with the APEX telescope in the frequency range 283.4-287.4�GHz. Based on the APEX observations, we report tentative detections of the {sup 13}C-methyl formate isotopologue HCOO{sup 13}CH{sub 3} toward the following four massive star-forming regions: Sgr B2(N-LMH), NGC�6334 IRS 1, W51 e2, and G19.61-0.23. In addition, we have used the 1�mm ALMA science verification observations of Orion-KL and confirm the detection of the {sup 13}C-methyl formate species in Orion-KL and image its spatial distribution. Our analysis shows that the {sup 12}C/{sup 13}C isotope ratio in methyl formate toward the Orion-KL Compact Ridge and Hot Core-SW components (68.4�� 10.1 and 71.4�� 7.8, respectively) are, for both the {sup 13}C-methyl formate isotopologues, commensurate with the average {sup 12}C/{sup 13}C ratio of CO derived toward Orion-KL. Likewise, regarding the other sources, our results are consistent with the {sup 12}C/{sup 13}C in CO. We also report the spectroscopic characterization, which includes a complete partition function, of the complex H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3} species. New spectroscopic data for both isotopomers H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3}, presented in this study, have made it possible to measure this fundamentally important isotope ratio in a large organic molecule for the first time.
Photophysics and morphology of poly (3-dodecylthienylenevinylene)-[6,6]-phenyl-C{sub 61}-butyric acid methyl ester composite
Lafalce, E.; Toglia, P.; Jiang, X.; Zhang, C.
A series of low band gap poly(3-dodecylthienylenevinylene) (PTV) with controlled morphological order have been synthesized and blended with the electron acceptor [6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM) for organic photovoltaic devices. Two polymers with the most and least side chain regioregularity were chosen in this work, namely the PTV010 and PTV55, respectively. Using photoluminescence, photo-induced absorption spectroscopy, and atomic force microscopy, we find no direct evidence of photoinduced charge transfer between the two constituents, independent of the bulk-heterojunction morphology of the film, although the possibility of formation of P{sup +}/C{sub 60}{sup -} charge transfer complex was not completely ruled out. The large exciton binding energy (E{sub b} = 0.6 eV) in PTV inhibits the photoinduced electron transfer from PTV to PCBM. In addition, excitons formed on polymer chains suffer ultrafast (
Accurate and Reliable Quantification of Total Microalgal Fuel Potential as Fatty Acid Methyl Esters by in situ Transesterfication
Laurens, L. M. L.; Quinn, M.; Van Wychen, S.; Templeton, D. W.; Wolfrum, E. J.
In the context of algal biofuels, lipids, or better aliphatic chains of the fatty acids, are perhaps the most important constituents of algal biomass. Accurate quantification of lipids and their respective fuel yield is crucial for comparison of algal strains and growth conditions and for process monitoring. As an alternative to traditional solvent-based lipid extraction procedures, we have developed a robust whole-biomass in situ transesterification procedure for quantification of algal lipids (as fatty acid methyl esters, FAMEs) that (a) can be carried out on a small scale (using 4-7 mg of biomass), (b) is applicable to a range of different species, (c) consists of a single-step reaction, (d) is robust over a range of different temperature and time combinations, and (e) tolerant to at least 50% water in the biomass. Unlike gravimetric lipid quantification, which can over- or underestimate the lipid content, whole biomass transesterification reflects the true potential fuel yield of algal biomass. We report here on the comparison of the yield of FAMEs by using different catalysts and catalyst combinations, with the acid catalyst HCl providing a consistently high level of conversion of fatty acids with a precision of 1.9% relative standard deviation. We investigate the influence of reaction time, temperature, and biomass water content on the measured FAME content and profile for 4 different samples of algae (replete and deplete Chlorella vulgaris, replete Phaeodactylum tricornutum, and replete Nannochloropsis sp.). We conclude by demonstrating a full mass balance closure of all fatty acids around a traditional lipid extraction process.
The neurotoxic effects of N-methyl-N-nitrosourea on the electrophysiological property and visual signal transmission of rat's retina
Tao, Ye; Chen, Tao; Liu, Bei; Yang, Guo Qing; Peng, Guanghua; Zhang, Hua; Huang, Yi Fei
The neurotoxic effects of N-methyl-N-nitrosourea (MNU) on the inner retinal neurons and related visual signal circuits have not been described in any animal models or human, despite ample morphological evidences about the MNU induced photoreceptor (PR) degeneration. With the helping of MEA (multielectrode array) recording system, we gained the opportunity to systemically explore the neural activities and visual signal pathways of MNU administrated rats. Our MEA research identified remarkable alterations in the electrophysiological properties and firstly provided instructive information about the neurotoxicity of MNU that affects the signal transmission in the inner retina. Moreover, the spatial electrophysiological functions of retina were monitored and found that the focal PRs had different vulnerabilities to the MNU. The MNU-induced PR dysfunction exhibited a distinct spatial- and time-dependent progression. In contrast, the spiking activities of both central and peripheral RGCs altered synchronously in response to the MNU administration. Pharmacological tests suggested that gap junctions played a pivotal role in this homogeneous response of RGCs. SNR analysis of MNU treated retina suggested that the signaling efficiency and fidelity of inner retinal circuits have been ruined by this toxicant, although the microstructure of the inner retina seemed relatively consolidated. The present study provided an appropriate example of MEA investigations on the toxicant induced pathological models and the effects of the pharmacological compounds on neuron activities. The positional MEA information would enrich our knowledge about the pathology of MNU induced RP models, and eventually be instrumental for elucidating the underlying mechanism of human RP. - Highlights: • We systemically explored the neural activities and visual signal pathways of MNU administrated retinas. • The focal photoreceptors had different vulnerabilities to the MNU administration. �
Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint
Tan, C.; Ong, H.Y.; Kok, P.W.
The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.
Acid-base properties, deactivation, and in situ regeneration of condensation catalysts for synthesis of methyl methacrylate
Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.
Condensation reaction of a propionate with formaldehyde is a novel route for synthesis of methyl methacrylate (MMA). The reaction mechanism involves a proton abstraction from the propionate on the basic sites and activation of the aliphatic aldehyde on the acidic sites of the catalyst. The acid-base properties of ternary V-Si-P oxide catalysts and their relation to the NWA yield in the vapor phase condensation of formaldehyde with propionic anhydride has been studied for the first time. Five different V-Si-P catalysts with different atomic ratios of vanadium, silicon, and phosphorous were synthesized, characterized, and tested in a fixed-bed microreactor system. A V-Si-P 1:10:2.8 catalyst gave the maximum condensation yield of 56% based on HCHO fed at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h. A parameter called the ``q-ratio`` has been defined to correlate the condensation yields to the acid-base properties. The correlation of q-ratio with the condensation yield shows that higher q-ratios are more desirable. The long-term deactivation studies on the V-Si-P 1: 10:2.8 catalyst at 300{degrees}C and 2 atm and at a space velocity of 290 cc/g cat{center_dot}h show that the catalyst activity drops by a factor of nearly 20 over a 180 h period. The activity can be restored to about 78% of the initial activity by a mild oxidative regeneration at 300{degrees}C and 2 atm. The performance of V-Si-P catalyst has been compared to a Ta/SiO{sub 2} catalyst. The Ta- catalyst is more stable and has a higher on-stream catalyst life.
Using physiologically based pharmacokinetic modeling to address nonlinear kinetics and changes in rodent physiology and metabolism due to aging and adaptation in deriving reference values for propylene glycol methyl ether and propylene glycol methyl ether acetate.
Kirman, C R.; Sweeney, Lisa M.; Corley, Rick A.; Gargas, M L.
Reference values, including an oral reference dose (RfD) and an inhalation reference concentration (RfC), were derived for propylene glycol methyl ether (PGME), and an oral RfD was derived for its acetate (PGMEA). These values were based upon transient sedation observed in F344 rats and B6C3F1 mice during a two-year inhalation study. The dose-response relationship for sedation was characterized using internal dose measures as predicted by a physiologically based pharmacokinetic (PBPK) model for PGME and its acetate. PBPK modeling was used to account for changes in rodent physiology and metabolism due to aging and adaptation, based on data collected during weeks 1, 2, 26, 52, and 78 of a chronic inhalation study. The peak concentration of PGME in richly perfused tissues was selected as the most appropriate internal dose measure based upon a consideration of the mode of action for sedation and similarities in tissue partitioning between brain and other richly perfused tissues. Internal doses (peak tissue concentrations of PGME) were designated as either no-observed-adverse-effect levels (NOAELs) or lowest-observed-adverse-effect levels (LOAELs) based upon the presence or absence of sedation at each time-point, species, and sex in the two year study. Distributions of the NOAEL and LOAEL values expressed in terms of internal dose were characterized using an arithmetic mean and standard deviation, with the mean internal NOAEL serving as the basis for the reference values, which was then divided by appropriate uncertainty factors. Where data were permitting, chemical-specific adjustment factors were derived to replace default uncertainty factor values of ten. Nonlinear kinetics are were predicted by the model in all species at PGME concentrations exceeding 100 ppm, which complicates interspecies and low-dose extrapolations. To address this complication, reference values were derived using two approaches which differ with respect to the order in which these extrapolations
Properties of electrospun CdS and CdSe filled poly(methyl methacrylate) (PMMA) nanofibres
Mthethwa, T.P.; Moloto, M.J.; De Vries, A.; Matabola, K.P.
Graphical abstract: SEM images of CdS/PMMA showing coiling as loading of CdS nanoparticles is increased. Thermal stability is increased with increase in %loading of both CdS and CdSe nanoparticles. Research highlights: {yields} TOPO-capped CdS and HDA-capped CdSe nanoparticles were synthesized and fully characterized. {yields} The nanoparticles were mixed with the polymer, PMMA using electrospinning technique using 2, 5 and 10% weight loadings. {yields} The mixture was spun to produce fibres with optical and thermal properties showing significant change and also the increase in loading causing bending or spiraling. {yields} Both TEM images for nanoparticles and SEM for fibres shows the morphology and sizes of the particles. -- Abstract: Electrospinning technique was used to fabricate poly(methyl methacrylate) (PMMA) fibres incorporating CdS and CdSe quantum dots (nanoparticles). Different nanoparticle loadings (2, 5 and 10 wt% with respect to PMMA) were used and the effect of the quantum dots on the properties of the fibres was studied. The optical properties of the hybrid composite fibres were investigated by photoluminescence and UV-vis spectrophotometry. Scanning electron microscopy (SEM), X-ray diffraction and FTIR spectrophotometry were also used to investigate the morphology and structure of the fibres. The optical studies showed that the size-tunable optical properties can be achieved in the polymer fibres by addition of quantum dots. SEM images showed that the morphologies of the fibres were dependent on the added amounts of quantum dots. A spiral type of morphology was observed with an increase in the concentration of CdS and CdSe nanoparticles. Less beaded structures and bigger diameter fibres were obtained at higher quantum dot concentrations. X-ray diffractometry detected the amorphous peaks of the polymer and even after the quantum dots were added and the FTIR analysis shows that there was no considerable interaction between the quantum dots and the
Manipulation of the HIF–Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions
Bonventre, Josephine A.; Kung, Tiffany S.; White, Lori A.; Cooper, Keith R.
Methyl tert-butyl ether (MTBE) has been shown to be specifically anti-angiogenic in piscine and mammalian model systems at concentrations that appear non-toxic in other organ systems. The mechanism by which MTBE targets developing vascular structures is unknown. A global transcriptome analysis of zebrafish embryos developmentally exposed to 0.00625–5 mM MTBE suggested that hypoxia inducible factor (HIF)-regulated pathways were affected. HIF-driven angiogenesis via vascular endothelial growth factor (vegf) is essential to the developing vasculature of an embryo. Three rescue studies were designed to rescue MTBE-induced vascular lesions: pooled blood in the common cardinal vein (CCV), cranial hemorrhages (CH), and abnormal intersegmental vessels (ISV), and test the hypothesis that MTBE toxicity was HIF–Vegf dependent. First, zebrafish vegf-a over-expression via plasmid injection, resulted in significantly fewer CH and ISV lesions, 46 and 35% respectively, in embryos exposed to 10 mM MTBE. Then HIF degradation was inhibited in two ways. Chemical rescue by N-oxaloylglycine significantly reduced CCV and CH lesions by 30 and 32% in 10 mM exposed embryos, and ISV lesions were reduced 24% in 5 mM exposed zebrafish. Finally, a morpholino designed to knock-down ubiquitin associated von Hippel–Lindau protein, significantly reduced CCV lesions by 35% in 10 mM exposed embryos. In addition, expression of some angiogenesis related genes altered by MTBE exposure were rescued. These studies demonstrated that MTBE vascular toxicity is mediated by a down regulation of HIF–Vegf driven angiogenesis. The selective toxicity of MTBE toward developing vasculature makes it a potentially useful chemical in the designing of new drugs or in elucidating roles for specific angiogenic proteins in future studies of vascular development. - Highlights: • Global gene expression of MTBE exposed zebrafish suggested altered HIF1 signaling. • Over expression of zebrafish vegf-a rescues MTBE
Analytical Methodologies for Detection of Gamma-Valerolactone, Delta-Valerolactone, Acephate and Azinphos Methyl and Their Associated Metabolites in Complex Biological Matrices
Zink, E.; Clark, R.; Grant, K.; Campbell, J.; Hoppe, E.
Non-invasive biomonitoring for chemicals of interest in law enforcement and similar monitoring of pesticides, together with their metabolites, can not only save money but can lead to faster medical attention for individuals exposed to these chemicals. This study describes methods developed for the analysis of gamma-valerolactone (GVL), delta-valerolactone (DVL), acephate, and azinphos methyl in saliva and serum. Liquid chromatography/mass spectrometry (LC/MS) operated in the negative and positive ion mode and gas chromatography/mass spectrometry (GC/MS) were used to analyze GVL and DVL. Although both analytical techniques worked well, lower detection limits were obtained with GC/MS. The lactones and their corresponding sodium salts were spiked into both saliva and serum. The lactones were isolated from saliva or serum using newly developed extraction techniques and then subsequently analyzed using GC/MS. The sodium salts of the lactones are nonvolatile and require derivatization prior to analysis by this method. N-methyl-N-(t-butyldimethylsilyl)-trifluoroacetamide (MTBSTFA) was ultimately selected as the reagent for derivatization because the acidic conditions required for reactions with diazomethane caused the salts to undergo intramolecular cyclization to the corresponding lactones. In vitro studies were conducted using rat liver microsomes to determine other metabolites associated with these compounds. Azinphos methyl and acephate are classified as organophosphate pesticides, and are known to be cholinesterase inhibitors in humans and insects, causing neurotoxicity. For this reason they have both exposure and environmental impact implications. These compounds were spiked into serum and saliva and prepared for analysis by GC/MS. Continuation of this research would include analysis by GC/MS under positive ion mode to determine the parent ions of the unknown metabolites. Further research is planned through an in vivo analysis of the lactones and pesticides. These
Analysis of methyl neodecanamide in lake water by reversed-phase high performance liquid chromatography and gas chromatography-mass spectrometry
Rasmussen, H.T.; Friedman, S.K.; Mustilli, A.J.; McDonough, R.; McPherson, B.P. )
Methyl Neodecanamide (MNDA) has been quantified in lake water at levels of 0.1 to 1,000 ppm. Total recoveries from spiked placebos were 99.8 [+-] 2.3% at the 1,000 ppm level and 98.3 [+-] 4.3% at the 0.1 ppm level (based on 54 determinations at each level). Plots of actual concentrations vs. determined concentrations were linear from 0.07--0.13 and 700--1,300 ppm (r > 0.999). Stability of MNDA in lake water was verified by determining the composition by GC/MS immediately after dissolution and after 3 days.
The structural organization of N-methyl-2-pyrrolidone + water mixtures: A densitometry, x-ray diffraction, and molecular dynamics study
Usula, M.; Marincola, F. Cesare; Porcedda, S.; Mocci, F.; Gontrani, L.; Caminiti, R.
A combined approach of molecular dynamics simulations, wide angle X-ray scattering experiments, and density measurements was employed to study the structural properties of N-methyl-2-pyrrolidone (NMP) + water mixtures over the whole concentration range. Remarkably, a very good agreement between computed and experimental densities and diffraction patterns was achieved, especially if the effect of the mixture composition on NMP charges is taken into account. Analysis of the intermolecular organization, as revealed by the radial and spatial distribution functions of relevant solvent atoms, nicely explained the density maximum observed experimentally.
Novel class of amino acid antagonists at non-N-methyl-D-aspartic acid excitatory amino acid receptors. Synthesis, in vitro and in vivo pharmacology, and neuroprotection
Krogsgaard-Larsen, P.; Ferkany, J.W.; Nielsen, E.O.; Madsen, U.; Ebert, B.; Johansen, J.S.; Diemer, N.H.; Bruhn, T.; Beattie, D.T.; Curtis, D.R. )
The isoxazole amino acid 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) (1), which is a highly selective agonist at the AMPA subtype of excitatory amino acid (EAA) receptors, has been used as a lead for the development of two novel EAA receptor antagonists. One of the compounds, 2-amino-3-(3-(carboxymethoxy)-5-methylisoxazol-4-yl)propionic acid (AMOA, 7), was synthesized via O-alkylation by ethyl chloroacetate of the amino acid protected AMPA derivative 4. The other compound, 2-amino-3-(2-(3-hydroxy-5-methylisoxazol-4-yl)-methyl-5-methyl-3-+ ++oxoisoxazolin -4-yl)propionic acid (AMNH, 14) was synthesized with use of 4-(chloromethyl)-3-methoxy-5-methylisoxazole (8) as the starting material. The intermediate 4-(chloromethyl)-2-(3-methoxy-5-methylisoxazol-4-yl)methyl-5-me thylisoxazolin- 3-one (11) was converted into the acetamidomalonate (12), which was stepwise deprotected to give 14. Compounds 7 and 14 were stable in aqueous solution at pH values close to physiological pH. Neither 7 nor 14 showed detectable affinities for the receptor, ion channel, or modulatory sites of the N-methyl-D-aspartic acid (NMDA) receptor complex. Quantitative receptor autoradiographic and conventional binding techniques were used to study the affinities of 7 and 14 for non-NMDA receptor sites. Both compounds were inhibitors of the binding of (3H)AMPA (IC50 = 90 and 29 microM, respectively). Compounds 14 and 7 were both very weak inhibitors of the high-affinity binding of radioactive kainic acid ((3H)KAIN). Compound 14, but not 7, was, however, shown to be an inhibitor of low-affinity (3H)KAIN binding as determined in the presence of 100 mM calcium chloride. In the rat cortical slice preparation, 7 was shown to antagonize excitation induced by 1 with some selectivity, whereas 14 proved to be a rather selective antagonist of KAIN-induced excitation.
Synthesis of 6-Methyl-9-propyldibenzothiophene-4-ol amended to 9-isopropyl-6-methyldibenzothiophene-4-ol. Final technical report, July 25, 1991--January 25, 1993
Eisenbraun, E.J.
This is a draft final technical report on Task 1 of a contract to synthesize 6-Methyl-9-propyldibenzothiophene-4-ol, as amended to 9- isopropyl-6-methyldibenzothiophene-4-ol. This report is a compilation of data presented in earlier reports. The first annual report dealt with an attempted synthesis of 4-methoxy-6-methyl-9- propyldibenzothiophene (the original target compound), the successful synthesis and delivery of 200 grams of the sulfide 1,4-diethyl-2- [(2{prime}-methoxyphenyl)-thio]benzene, and initial work on a new synthesis route for the preparation of the new target compound 9- isopropyl-6-methyldibenzothiophene-4-ol. The change to the new target compound and the new synthesis route became necessary when it was learned that the sulfide mixture could not be cyclized to the substituted dibenzothiophene mixture. The second annual report described the successful preparation of 45 g of the new target compound using the new synthesis route. Subsequently funds were provided to synthesize an additional 45 g of the new target using the same reaction scheme. This task was recently completed.
INSIGHTS INTO SURFACE HYDROGENATION IN THE INTERSTELLAR MEDIUM: OBSERVATIONS OF METHANIMINE AND METHYL AMINE IN Sgr B2(N)
Halfen, D. T.; Ziurys, L. M.; Ilyushin, V. V. E-mail: firstname.lastname@example.com
Multiple observations of methanimine (CH{sub 2}NH) and methyl amine (CH{sub 3}NH{sub 2}) have been performed toward Sgr B2(N) at 1, 2, and 3 mm using the Submillimeter Telescope and the 12 m antenna of the Arizona Radio Observatory. In the frequency range 68-280 GHz, 23 transitions of CH{sub 2}NH and 170 lines of CH{sub 3}NH{sub 2} have been observed as individual, distinguishable features, although some are partially blended with other lines. For CH{sub 2}NH, the line profiles indicate V{sub LSR} = 64.2 {+-} 1.4 km s{sup -1} and {Delta}V{sub 1/2} = 13.8 {+-} 2.8 km s{sup -1}, while V{sub LSR} = 63.7 {+-} 1.6 km s{sup -1} and {Delta}V{sub 1/2} = 15.1 {+-} 3.0 km s{sup -1} for CH{sub 3}NH{sub 2}, parameters that are very similar to those of other organic species in Sgr B2(N). From these data, rotational diagrams were constructed for both species. In the case of CH{sub 2}NH, a rotational temperature of T{sub rot} = 44 {+-} 13 K and a column density of N{sub tot} = (9.1 {+-} 4.4) Multiplication-Sign 10{sup 14} cm{sup -2} were determined from the analysis. For CH{sub 3}NH{sub 2}, T{sub rot} = 159 {+-} 30 K and N{sub tot} = (5.0 {+-} 0.9) Multiplication-Sign 10{sup 15} cm{sup -2}, indicating that this species is present in much warmer gas than CH{sub 2}NH. The fractional abundances for CH{sub 2}NH and CH{sub 3}NH{sub 2} were established to be f (H{sub 2}) Almost-Equal-To 3.0 Multiplication-Sign 10{sup -10} and f (H{sub 2}) Almost-Equal-To 1.7 Multiplication-Sign 10{sup -9}, respectively. It has been proposed that CH{sub 2}NH is formed on grains via hydrogenation of HCN; further hydrogenation of CH{sub 2}NH on surfaces leads to CH{sub 3}NH{sub 2}. However, given the dissimilarity between the rotational temperatures and distributions of CH{sub 2}NH and CH{sub 3}NH{sub 2} in Sgr B2, it is improbable that these species are closely related synthetically, at least in this source. Both CH{sub 2}NH and CH{sub 3}NH{sub 2} are more likely created by neutral-neutral processes in
Discovery of 5-[[4-[(2,3-Dimethyl-2H-indazol-6-yl)methylamino]-2-pyrimidinyl]amino]-2-methyl-benzenesulfonamide (Pazopanib), a Novel and Potent Vascular Endothelial Growth Factor Receptor Inhibitor
Harris, Philip A.; Boloor, Amogh; Cheung, Mui; Kumar, Rakesh; Crosby, Renae M.; Davis-Ward, Ronda G.; Epperly, Andrea H.; Hinkle, Kevin W.; Hunter, III, Robert N.; Johnson, Jennifer H.; Knick, Victoria B.; Laudeman, Christopher P.; Luttrell, Deirdre K.; Mook, Robert A.; Nolte, Robert T.; Rudolph, Sharon K.; Szewczyk, Jerzy R.; Truesdale, Anne T.; Veal, James M.; Wang, Liping; Stafford, Jeffrey A.
Inhibition of the vascular endothelial growth factor (VEGF) signaling pathway has emerged as one of the most promising new approaches for cancer therapy. We describe herein the key steps starting from an initial screening hit leading to the discovery of pazopanib, N{sup 4}-(2,3-dimethyl-2H-indazol-6-yl)-N{sup 4}-methyl-N{sup 2}-(4-methyl-3-sulfonamidophenyl)-2,4-pyrimidinediamine, a potent pan-VEGF receptor (VEGFR) inhibitor under clinical development for renal-cell cancer and other solid tumors.
Annual Energy Outlook [U.S. Energy Information Administration (EIA)]
Report The Form EIA-819, "Monthly Oxygenate Report" provides production data for fuel ethanol and methyl tertiary butyl ether (MTBE). End-of-month stock data held at ethanol...
Preparations for Meeting New York and Connecticut MTBE Bans
Reports and Publications (EIA)
In response to a Congressional request, the Energy Information Administration examined the progress being made to meet the bans on the use of methyl tertiary butyl ether (MTBE) being implemented in New York and Connecticut at the end of 2003.
Crystallization of lysozyme with (R)-, (S)- and (RS)-2-methyl-2,4-pentanediol
Stauber, Mark; Jakoncic, Jean; Berger, Jacob; Karp, Jerome M.; Axelbaum, Ariel; Sastow, Dahniel; Buldyrev, Sergey V.; Hrnjez, Bruce J.; Asherie, Neer
Chiral control of crystallization has ample precedent in the small-molecule world, but relatively little is known about the role of chirality in protein crystallization. In this study, lysozyme was crystallized in the presence of the chiral additive 2-methyl-2,4-pentanediol (MPD) separately using the R and S enantiomers as well as with a racemic RS mixture. Crystals grown with (R)-MPD had the most order and produced the highest resolution protein structures. This result is consistent with the observation that in the crystals grown with (R)-MPD and (RS)-MPD the crystal contacts are made by (R)-MPD, demonstrating that there is preferential interaction between lysozyme and this enantiomer. These findings suggest that chiral interactions are important in protein crystallization.
On the correlation between the photoexcitation pathways and the critical energies required for ablation of poly(methyl methacrylate): A molecular dynamics study
Conforti, Patrick F.; Prasad, Manish; Garrison, Barbara J.
The energetics initiating ablation in poly(methyl methacrylate) (PMMA) are studied using molecular dynamics (MD) simulation. The critical energy to initiate ablation in PMMA following the absorption of photons is investigated for two penetration depths along a range of fluences using a coarse-grained, hybrid Monte Carlo-MD scheme. Both heating and direct bond scission are simulated separately after photon absorption with additional transformation of material occurring via chemical reactions following the photochemical bond cleavage. For a given type of absorption and reaction channel, a critical energy can well describe the amount of energy required to initiate ablation. The simulations show a decrease in the critical energy when a greater amount of photochemistry is introduced in the system. The simulations complement experimental studies and elucidate how enhanced photochemistry lowers ablation thresholds in polymer substrates.
Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace
Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.; Williams, Philip G.; Biegon, Anat
The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.
Broadband gain in poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester photodetectors enabled by a semicontinuous gold interlayer
Melancon, Justin M.; Živanović, Sandra R.
Substantial broadband photoconductive gain has been realized for organic, thin-film photodetectors with a poly(3-hexylthiophene):phenyl-C{sub 61}-butyric-acid-methyl-ester (P3HT:PCBM) active layer at low bias voltages. External quantum efficiencies upwards of 1500% were achieved when a semicontinuous gold layer was introduced at the anode interface. Significant gain was also observed in the sub-band gap, near infrared region where the external quantum efficiency approached 100% despite the lack of a sensitizer. The gain response was highly dependent on the thickness of the active layer of the photodetector with the best results achieved with the thinnest devices. The gain is the result of the injection of secondary electrons due to hole charge trapping at the semicontinuous gold layer.
Synthesis, characterization, and crystal structure of 2-amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2-c] pyran-3-carbonitrile
Sharma, S.; Banerjee, B.; Brahmachari, G.; Kant, Rajni; Gupta, V. K.
2-Amino-7-methyl-5-oxo-4-phenyl-4,5-dihydropyrano[3,2-c] pyran-3-carbonitrile, C{sub 16}H{sub 12}N{sub 2}O{sub 3} is synthesized via one-pot multi-component reaction at room temperature using commercially available urea as inexpensive and environmentally benign organo-catalyst. Its structure is determined by single-crystal X-ray diffraction technique The crystals are monoclinic, a = 10.7357(12), b = 8.7774(8), c = 15.0759(16) Å, β = 103.575(11)°, Z = 4, sp. gr. P2{sub 1}/n, R = 0.0551 for 1696 observed reflections. The crystal structure is stabilized by N–H···N, C–H···O, and C–H···π interactions.
K20E, an oxidative-coupling compound of methyl caffeate, exhibits anti-angiogenic activities through down-regulations of VEGF and VEGF receptor-2
Pan, Chun-Hsu; Lin, Wen-Hsin; Chien, Yi-Chung; Liu, Fon-Chang; Sheu, Ming-Jyh; Kuo, Yueh-Hsiung; Wu, Chieh-Hsi
Anti-angiogenesis is one of the most popular clinical interventions for cancer chemotherapy. A series of synthesized derivative of methyl caffeate were used to evaluate the anti-angiogenic activity and to investigate possible pharmacological mechanisms in the present study. The most potent anti-angiogenic compound was evaluated in the experiments of murine allograft tumor model and Matrigel plug assay as well as cell models in the human umbilical vascular endothelial cells (HUVECs) and the LLC1 lung cancer cells. Our results suggested that K20E suppressed the tumor growth in the allograft tumor model and exhibited anti-angiogenic activity in Matrigel plug assay. Besides, HUVEC viability was found to be significantly reduced by arresting cell cycle at G{sub 2}/M phase and apoptosis. Cell migration, invasion, and tube formation of the HUVECs were also markedly suppressed by K20E treatment. K20E largely down-regulated the intracellular and secreted vascular endothelial growth factor (VEGF) in the LLC1 cancer cells. Besides, VEGF receptor-2 (VEGFR-2) and its downstream signaling cascades (AKT-mTOR and MEK1/2-ERK1/2) as well as gelatinases were all evidently reduced in the HUVECs treated with K20E. Inversely, K20E can up-regulate the expression levels of p53 and p21 proteins in the HUVECs. Based on these results, our study suggested that K20E possessed inhibiting angiogenesis through regulation of VEGF/VEGFR-2 and its downstream signaling cascades in the vascular endothelial cells (VECs). - Highlights: • K20E is an oxidative-coupling compound of methyl caffeate. • K20E exhibits anti-tumor and anti-angiogenesis effects. • K20E suppresses the expressions of VEGF and VEGF receptor-2 (VEGFR-2) proteins. • K20E deactivates VEGFR-2-mediated downstream signaling pathways to inhibit angiogenesis. • K20E up-regulates p53-p21 pathway to induce apoptosis and cell arrest at G2/M phase.
Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds
Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.
The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.
Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells
Lee, Kyung-Mi; Yun, Ji Ho; Lee, Dong Hwa; Park, Young Gyun; Son, Kun Ho; Nho, Chu Won; Kim, Yeong Shik
We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers. - Highlights: • CME inhibits cell proliferation in HCT116 cells. • CME increases cell cycle arrest at G0/G1 phase and apoptosis. • CME attenuates cyclin D1 and regulates cell cycle regulatory proteins. • CME inhibits β-catenin translocation to nucleus.
Emissions characteristics of ethyl and methyl ester of rapeseed oil compared with low sulfur diesel control fuel in a chassis dynamometer test of a pickup truck
Peterson, C.; Reece, D.
Comprehensive tests were performed on an on-road vehicle in cooperation with the Los Angeles County Metropolitan Transit Authority emissions test facility. All tests were with a transient chassis dynamometer. Tests included both a double arterial cycle of 768 s duration and an EPA heavy duty vehicle cycle of 1,060 s duration. The test vehicle was a 1994 pickup truck with a 5.9-L turbocharged and intercooled, direct injection diesel engine. Rapeseed methyl (RME) and ethyl esters (REE) and blends were compared with low sulfur diesel control fuel. Emissions data include all regulated emissions: hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO{sub 2}), oxides of nitrogen (NO{sub x}), and particulate matter (PM). In these tests the average of 100% RME and 100% REE reduced HC (52.4%), CO (47.6%), NO{sub x} (10.0%), and increases in CO{sub 2} (0.9%) and PM (9.9%) compared to the diesel control fuel. Also, 100% REE reduced HC (8.7%), CO (4.3%), and NO{sub x} (3.4%) compared to 100% RME. 33 refs., 1 figs., 8 tabs.
Direct photo-etching of poly(methyl methacrylate) using focused extreme ultraviolet radiation from a table-top laser-induced plasma source
Barkusky, Frank; Peth, Christian; Bayer, Armin; Mann, Klaus
In order to perform material interaction studies with intense extreme ultraviolet (EUV) radiation, a Schwarzschild mirror objective coated with Mo/Si multilayers was adapted to a compact laser-based EUV plasma source (pulse energy 3 mJ at {lambda}=13.5 nm, plasma diameter {approx}300 {mu}m). By 10x demagnified imaging of the plasma a pulse energy density of {approx}75 mJ/cm{sup 2} at a pulse length of 6 ns can be achieved in the image plane of the objective. As demonstrated for poly(methyl methacrylate) (PMMA), photoetching of polymer surfaces is possible at this EUV fluence level. This paper presents first results, including a systematic determination of PMMA etching rates under EUV irradiation. Furthermore, the contribution of out-of-band radiation to the surface etching of PMMA was investigated by conducting a diffraction experiment for spectral discrimination from higher wavelength radiation. Imaging of a pinhole positioned behind the plasma accomplished the generation of an EUV spot of 1 {mu}m diameter, which was employed for direct writing of surface structures in PMMA.
Stereochemical effects in the gas-phase pinacol rearrangement. 2. Ring contraction versus methyl migration in cis- and trans-1,2-dimethylcyclohexane-1,2-diol
de Petris, G.; Giacomello, P.; Pizzabiocca, A.; Renzi, G.; Speranza, M.
The gas-phase pinacol rearrangement of cis- and trans-1,2-dimethylcyclohexane-1,2-diols, promoted by D/sub 3//sup +/, CH/sub 5//sup +//C/sub 2/H/sub 5//sup +/ and t-C/sub 4/H/sub 9//sup +/ ions, was studied by mass spectrometric and radiolytic methods in the pressure range 0.5-760 Torr. When product isomerization is inhibited, by using N(CH/sub 3/)/sub 3/ as a trapping reagent at high pressure, mixtures of 2,2-dimethylcyclohexanone and 1-acetyl-1-methylcyclopentane were recovered from the reaction. In methane, the trend of the measured relative rates for ring contraction (k/sub 5/), methyl or hydroxyl group migration (k/sub 6/) versus the rearrangement rate of pincaol itself (k/sub p/), is k/sub 6/(trans) approx. k/sub 5/(trans) greater than or equal to k/sub 5/(cis) > k/sub 6/(cis) greater than or equal to k/sub p/. No evidence for the formation of an intermediate carbenium ion was found. Stereochemical aspects of the mechanism are discussed and compared with solution data.
Preparation of 3R- and 3S-methyl isomers of the myocardial imaging agent 15-(p-IODOPHENYL)-3-methylpentadecanoic acid ({open_quotes}BMIPP{close_quotes})
Lin, Q. |; Luo, J.; Mokler, F.
Iodine-123-labeled racemic BMIPP is used for clinical evaluation of heart disease. To evaluate the expected importance of configuration of the asymmetric C-3 center, we have synthesized the 3R-isomer. 6-Phenylhexanoyl chloride was condensed with thiophene (Friedel-Crafts), followed by Wolff-Kishner reduction and subsequent acylation with the ethyl-3-R-methylglutaroyl chloride, Wolff-Kishner reduction and Raney-Ni ring opening. Para Thallation (TTFA)/KI provided 3R-BMIPP, m.p. 51-52{degrees}C, [{alpha}{sub D}] = +0.74{degrees}. The diastereomeric amide mixture was prepared by reaction of racemic 3-R,S-BMIPP with (S)-(-)-{alpha}-methylbenzylamine. Chromatographic separation and HCl hydrolysis (at 175{degrees}C) provided the 3R- and 3S- (m.p. 45-46{degrees}C, [{alpha}{sub D}] = -1.67{degrees}) BMIPP isomers. The more polar amide (m.p. 93-94{degrees}C) was identical with the amide from the synthetic 3R-BMIPP (m.p., HPLC, NMR). Availability of the 3R- and 3S-BMIPP isomers will permit preparation of the radioiodinated isomers and animal evaluation to determine the effects of the methyl group configuration on myocardial uptake and metabolism.
Pump-beam-induced optical damage depended on repetition frequency and pulse width in 4-dimethylamino-N Prime -methyl-4 Prime -stilbazolium tosylate crystal
Matsukawa, Takeshi; Nawata, Kouji; Notake, Takashi; Qi Feng; Kawamata, Hiroshi; Minamide, Hiroaki
We investigated the dependence of optical damage to an organic nonlinear optical crystal of 4-dimethylamino-N Prime -methyl-4 Prime -stilbazolium tosylate (DAST) on the repetition frequency and pulse width of the pump beam used to cause the thermal damage. For a pump beam with a pulse width of 15 ns at a wavelength of 1064 nm, the highest damage threshold of 8.0 J/cm{sup 2} was measured for repetition frequencies in the range from 10 to 40 Hz. On the other hand, DAST crystals were easily damaged under the repetition rates from 50 to 100 Hz. For 600-ps pulses, a higher damage threshold that was a factor of 11 to 28 times higher in terms of peak intensity was obtained compared with that of 15-ns pulses. In both the cases of 15-ns pulse duration and 600-ps duration, we demonstrated that the thermal effects in DAST crystals dominated the optical damage, which depended on thermal accumulation and dissipation.
Molecular and crystal structures of 4'-hydroxy derivative of (3R,6R)-3-methyl-6-isopropyl-2-(4-phenylbenzylidene)cyclohexanone
Kutulya, L. A.; Kulishov, V. I.; Shishkina, S. V.; Tolochko, A. S.; Roshal', A. D.; Shishkin, O. V.
The molecular and crystal structures of the 4-hydroxy derivative of (3R,6R)-3-methyl-6-isopropyl-2-(4-phenylbenzylidene)cyclohexanone are determined by X-ray diffraction analysis. Single crystals are orthorhombic, a = 9.147(2) A, b = 12.959(2) A, c = 15.695(5) A, V = 1860.4(7) A{sup 3}, Z = 4, and space group P2{sub 1}2{sub 1}2{sub 1}. The cyclohexanone ring in the crystal structure has an asymmetric chair conformation. The puckering parameters are as follows: the puckering amplitude S is 0.91, and the puckering angles {theta} and {psi} are equal to 20.2{sup o} and 10.4{sup o}, respectively. It is established that the enone fragment and the cyclohexanone ring in molecules are flattened considerably. In the crystal structure, the molecules are linked by the hydrogen bonds (bond length, 1.85 A). The structural features and the strength of the hydrogen bonds for the compound under investigation and its analogue with one benzene ring are compared using the X-ray diffraction and IR spectroscopic data.
Dynamic heterogeneity of DNA methylation and hydroxymethylation in embryonic stem cell populations captured by single-cell 3D high-content analysis
Tajbakhsh, Jian; Stefanovski, Darko; Tang, George; Wawrowsky, Kolja; Liu, Naiyou; Fair, Jeffrey H.
Cell-surface markers and transcription factors are being used in the assessment of stem cell fate and therapeutic safety, but display significant variability in stem cell cultures. We assessed nuclear patterns of 5-hydroxymethylcytosine (5hmC, associated with pluripotency), a second important epigenetic mark, and its combination with 5-methylcytosine (5mC, associated with differentiation), also in comparison to more established markers of pluripotency (Oct-4) and endodermal differentiation (FoxA2, Sox17) in mouse embryonic stem cells (mESC) over a 10-day differentiation course in vitro: by means of confocal and super-resolution imaging together with 3D high-content analysis, an essential tool in single-cell screening. In summary: 1) We did not measure any significant correlation of putative markers with global 5mC or 5hmC. 2) While average Oct-4 levels stagnated on a cell-population base (0.015 lnIU/day), Sox17 and FoxA2 increased 22-fold and 3-fold faster, respectively (Sox17: 0.343 lnIU/day; FoxA2: 0.046 lnIU/day). In comparison, global DNA methylation levels increased 4-fold faster (0.068 lnIU/day), and global hydroxymethylation declined at 0.046 lnIU/day, both with a better explanation of the temporal profile. 3) This progression was concomitant with the occurrence of distinct nuclear codistribution patterns that represented a heterogeneous spectrum of states in differentiation; converging to three major coexisting 5mC/5hmC phenotypes by day 10: 5hmC{sup +}/5mC{sup −}, 5hmC{sup +}/5mC{sup +}, and 5hmC{sup −}/5mC{sup +} cells. 4) Using optical nanoscopy we could delineate the respective topologies of 5mC/5hmC colocalization in subregions of nuclear DNA: in the majority of 5hmC{sup +}/5mC{sup +} cells 5hmC and 5mC predominantly occupied mutually exclusive territories resembling euchromatic and heterochromatic regions, respectively. Simultaneously, in a smaller subset of cells we observed a tighter colocalization of the two cytosine variants, presumably
Spatiotemporal temperature and density characterization of high-power atmospheric flashover discharges over inert poly(methyl methacrylate) and energetic pentaerythritol tetranitrate dielectric surfaces
Tang, V.; Grant, C. D.; McCarrick, J. F.; Zaug, J. M.; Glascoe, E. A.; Wang, H.
A flashover arc source that delivered up to 200 mJ on the 100s-of-ns time-scale to the arc and a user-selected dielectric surface was characterized for studying high-explosive kinetics under plasma conditions. The flashover was driven over thin pentaerythritol tetranitrate (PETN) and poly(methyl methacrylate) (PMMA) dielectric films and the resultant plasma was characterized in detail. Time- and space-resolved temperatures and electron densities of the plasma were obtained using atomic emission spectroscopy. The hydrodynamics of the plasma was captured through fast, visible imaging. Fourier transform infrared spectroscopy (FTIR) was used to characterize the films pre- and post-shot for any chemical alterations. Time-resolved infrared spectroscopy (TRIR) provided PETN depletion data during the plasma discharge. For both types of films, temperatures of 1.6-1.7 eV and electron densities of {approx}7-8 x 10{sup 17}/cm{sup 3}{approx}570 ns after the start of the discharge were observed with temperatures of 0.6-0.7 eV persisting out to 15 {mu}s. At 1.2 {mu}s, spatial characterization showed flat temperature and density profiles of 1.1-1.3 eV and 2-2.8 x 10{sup 17}/cm{sup 3} for PETN and PMMA films, respectively. Images of the plasma showed an expanding hot kernel starting from radii of {approx}0.2 mm at {approx}50 ns and reaching {approx}1.1 mm at {approx}600 ns. The thin films ablated or reacted several hundred nm of material in response to the discharge. First TRIR data showing the in situ reaction or depletion of PETN in response to the flashover arc were successfully obtained, and a 2-{mu}s, 1/e decay constant was measured. Preliminary 1 D simulations compared reasonably well with the experimentally determined plasma radii and temperatures. These results complete the first steps to resolving arc-driven PETN reaction pathways and their associated kinetic rates using in situ spectroscopy techniques.
Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine
Li, Yamin; Xiao, Changyu; Zhang, Xudong; Xu, Yanhui; Li, Junrui; Lun, Huijie; Chen, Qi
Two new transition metal coordination complexes, ([MnO(nda)](H{sub 2}dmt)(H{sub 2}O)){sub n} (1), [Ag{sub 5}(nda){sub 2.5}(dmt)]{sub n} (2), (H{sub 2}nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H{sub 2}nda and dmt with the homologous MnCl{sub 2}·4H{sub 2}O and AgNO{sub 3}, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain (MnO(CO{sub 2}){sub 2}){sub n} connected by the ligand nda{sup 2−}, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda{sup 2−}, with a rare 2-nodal (3,8)-connected tfz-d topology ((4{sup 3}){sub 2}(4{sup 6}.6{sup 18}.8{sup 4})). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1) cm{sup −1}, zj′=−0.73(2) cm{sup −1}). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λ{sub ex}=394 nm). - Graphical abstract: Two new transition metal coordination complexes 1–2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis thermogravimetric analysis (TGA). Highlights: • The compound 1 exhibits a 3D network with four-connected uninodal diamond-like topology. • The first 3D network of 2 with a rare tfz-d topology consists of decanuclear silver clusters as secondary building units. • The magnetic measurement indicates the compound 1 shows antiferromagnetic interactions. • The photoluminescent property of 2 has been measured.
Determination of the effective diffusivity of water in a poly (methyl methacrylate) membrane containing carbon nanotubes using kinetic Monte Carlo simulations
Mermigkis, Panagiotis G.; Tsalikis, Dimitrios G.; Mavrantzas, Vlasis G.
A kinetic Monte Carlo (kMC) simulation algorithm is developed for computing the effective diffusivity of water molecules in a poly(methyl methacrylate) (PMMA) matrix containing carbon nanotubes (CNTs) at several loadings. The simulations are conducted on a cubic lattice to the bonds of which rate constants are assigned governing the elementary jump events of water molecules from one lattice site to another. Lattice sites belonging to PMMA domains of the membrane are assigned different rates than lattice sites belonging to CNT domains. Values of these two rate constants are extracted from available numerical data for water diffusivity within a PMMA matrix and a CNT pre-computed on the basis of independent atomistic molecular dynamics simulations, which show that water diffusivity in CNTs is 3 orders of magnitude faster than in PMMA. Our discrete-space, continuum-time kMC simulation results for several PMMA-CNT nanocomposite membranes (characterized by different values of CNT length L and diameter D and by different loadings of the matrix in CNTs) demonstrate that the overall or effective diffusivity, D{sub eff}, of water in the entire polymeric membrane is of the same order of magnitude as its diffusivity in PMMA domains and increases only linearly with the concentration C (vol. %) in nanotubes. For a constant value of the concentration C, D{sub eff} is found to vary practically linearly also with the CNT aspect ratio L/D. The kMC data allow us to propose a simple bilinear expression for D{sub eff} as a function of C and L/D that can describe the numerical data for water mobility in the membrane extremely accurately. Additional simulations with two different CNT configurations (completely random versus aligned) show that CNT orientation in the polymeric matrix has only a minor effect on D{sub eff} (as long as CNTs do not fully penetrate the membrane). We have also extensively analyzed and quantified sublinear (anomalous) diffusive phenomena over small to moderate
Quercetin 3-O-methyl ether protects FL83B cells from copper induced oxidative stress through the PI3K/Akt and MAPK/Erk pathway
Tseng, Hsiao-Ling; Li, Chia-Jung; Huang, Lin-Huang; Chen, Chun-Yao; Tsai, Chun-Hao; Lin, Chun-Nan; Department of Biological Science and Technology, School of Medicine, China Medical University, Taichung, Taiwan ; Hsu, Hsue-Yin
Quercetin is a bioflavonoid that exhibits several biological functions in vitro and in vivo. Quercetin 3-O-methyl ether (Q3) is a natural product reported to have pharmaceutical activities, including antioxidative and anticancer activities. However, little is known about the mechanism by which it protects cells from oxidative stress. This study was designed to investigate the mechanisms by which Q3 protects against Cu{sup 2+}-induced cytotoxicity. Exposure to Cu{sup 2+} resulted in the death of mouse liver FL83B cells, characterized by apparent apoptotic features, including DNA fragmentation and increased nuclear condensation. Q3 markedly suppressed Cu{sup 2+}-induced apoptosis and mitochondrial dysfunction, characterized by reduced mitochondrial membrane potential, caspase-3 activation, and PARP cleavage, in Cu{sup 2+}-exposed cells. The involvement of PI3K, Akt, Erk, FOXO3A, and Mn-superoxide dismutase (MnSOD) was shown to be critical to the survival of Q3-treated FL83B cells. The liver of both larval and adult zebrafish showed severe damage after exposure to Cu{sup 2+} at a concentration of 5 μM. Hepatic damage induced by Cu{sup 2+} was reduced by cotreatment with Q3. Survival of Cu{sup 2+}-exposed larval zebrafish was significantly increased by cotreatment with 15 μM Q3. Our results indicated that Cu{sup 2+}-induced apoptosis in FL83B cells occurred via the generation of ROS, upregulation and phosphorylation of Erk, overexpression of 14-3-3, inactivation of Akt, and the downregulation of FOXO3A and MnSOD. Hence, these results also demonstrated that Q3 plays a protective role against oxidative damage in zebrafish liver and remarked the potential of Q3 to be used as an antioxidant for hepatocytes. Highlights: ► Protective effects of Q3 on Cu{sup 2+}-induced oxidative stress in vitro and in vivo. ► Cu{sup 2+} induced apoptosis in FL83B cells via ROS and the activation of Erk. ► Q3 abolishes Cu{sup 2+}-induced apoptosis through the PI3K/Akt and MAPK
OE Releases "Transmission Constraints and Congestion in the Western and
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Eastern Interconnections, 2009-2012" | Department of Energy Releases "Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012" OE Releases "Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012" February 4, 2014 - 5:14pm Addthis The "Transmission Constraints and Congestion in the Western and Eastern Interconnections, 2009-2012" document, which is now available for downloading,
Table Definitions, Sources, and Explanatory Notes
Gasoline and Diesel Fuel Update (EIA)
Ethanol Plant Production Definitions Key Terms Definition Barrel A unit of volume equal to 42 U.S. gallons. Fuel Ethanol An anhydrous alcohol (ethanol with less than 1% water) intended for gasoline blending as described in the Oxygenates definition. Oxygenates Substances which, when added to gasoline, increase the amount of oxygen in that gasoline blend. Ethanol, Methyl Tertiary Butyl Ether (MTBE), Ethyl Tertiary Butyl Ether (ETBE), and methanol are common oxygenates. Fuel Ethanol: Blends of up
Graphene composite for improvement in the conversion efficiency of flexible poly 3-hexyl-thiophene:[6,6]-phenyl C{sub 71} butyric acid methyl ester polymer solar cells
Chauhan, A. K., E-mail: email@example.com, E-mail: firstname.lastname@example.com; Gusain, Abhay; Jha, P.; Koiry, S. P.; Saxena, Vibha; Veerender, P.; Aswal, D. K.; Gupta, S. K. [Technical Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)
The solution of thin graphene-sheets obtained from a simple ultrasonic exfoliation process was found to chemically interact with [6,6]-phenyl C{sub 71} butyric acid methyl ester (PCBM) molecules. The thinner graphene-sheets have significantly altered the positions of highest occupied molecular orbital and lowest unoccupied molecular orbital of PCBM, which is beneficial for the enhancement of the open circuit voltage of the solar cells. Flexible bulk heterojunction solar cells fabricated using poly 3-hexylthiophene (P3HT):PCBM-graphene exhibited a power conversion efficiency of 2.51%, which is a ?2-fold increase as compared to those fabricated using P3HT:PCBM. Inclusion of graphene-sheets not only improved the open-circuit voltage but also enhanced the short-circuit current density owing to an improved electron transport.
Process for tertiary oil recovery using tall oil pitch
Radke, Clayton J.
Compositions and process employing same for enhancing the recovery of residual acid crudes, particularly heavy crudes, by injecting a composition comprising caustic in an amount sufficient to maintain a pH of at least about 11, preferably at least about 13, and a small but effective amount of a multivalent cation for inhibiting alkaline silica dissolution with the reservoir. Preferably a tall oil pitch soap is included and particularly for the heavy crudes a polymeric mobility control agent.
Process for tertiary oil recovery using tall oil pitch
Radke, C.J.
A process and compositions for enhancing the recovery of acid crudes are disclosed. The process involves injecting caustic solutions into the reservoir to maintain a pH of 11 to 13. The fluid contains an effective amount of multivalent cation for inhibiting alkaline silica dissolution with the reservoir. A tall oil pitch soap is added as a polymeric mobility control agent. (DMC)
Mesoporous tertiary oxides via a novel amphiphilic approach
Bennett, Natasha; Hall, Simon R. E-mail: email@example.com; Seddon, Annela M. E-mail: email@example.com; Hallett, James E.; Kockelmann, Winfried; Ting, Valeska P.; Sadasivan, Sajanikumari; Tooze, Robert P.
We report a facile biomimetic sol-gel synthesis using the sponge phase formed by the lipid monoolein as a structure-directing template, resulting in high phase purity, mesoporous dysprosium- and gadolinium titanates. The stability of monoolein in a 1,4-butanediol and water mixture complements the use of a simple sol-gel metal oxide synthesis route. By judicious control of the lipid/solvent concentration, the sponge phase of monoolein can be directly realised in the pyrochlore material, leading to a porous metal oxide network with an average pore diameter of 10 nm.
{gamma}-aminobutyric acid{sub A} (GABA{sub A}) receptor regulates ERK1/2 phosphorylation in rat hippocampus in high doses of Methyl Tert-Butyl Ether (MTBE)-induced impairment of spatial memory
Zheng Gang; Zhang Wenbin; Zhang Yun; Chen Yaoming; Liu Mingchao; Yao Ting; Yang Yanxia; Zhao Fang; Li Jingxia; Huang Chuanshu; Luo Wenjing Chen Jingyuan
Experimental and occupational exposure to Methyl Tert-Butyl Ether (MTBE) has been reported to induce neurotoxicological and neurobehavioral effects, such as headache, nausea, dizziness, and disorientation, etc. However, the molecular mechanisms involved in MTBE-induced neurotoxicity are still not well understood. In the present study, we investigated the effects of MTBE on spatial memory and the expression and function of GABA{sub A} receptor in the hippocampus. Our results demonstrated that intraventricular injection of MTBE impaired the performance of the rats in a Morris water maze task, and significantly increased the expression of GABA{sub A} receptor {alpha}1 subunit in the hippocampus. The phosphorylation of ERK1/2 decreased after the MTBE injection. Furthermore, the decreased ability of learning and the reduction of phosphorylated ERK1/2 level of the MTBE-treated rats was partly reversed by bicuculline injected 30 min before the training. These results suggested that MTBE exposure could result in impaired spatial memory. GABA{sub A} receptor may play an important role in the MTBE-induced impairment of learning and memory by regulating the phosphorylation of ERK in the hippocampus.
A fragile X male with a broad smear on southern blot analysis representing 100-500 CGG repeats and no methylation at the EagI site of the FMR-1 gene
Lachiewicz, A.M.; Spiridigliozzi, G.A.; McConkie-Rosell, A.
Fragile X DNA studies were carried out on all obligate carriers of a large fragile X family with 10 mentally retarded individuals. One 64-year-old carrier man with an altered FMR-1 allele was not described as being mentally retarded or as having any limitations in function. He was married, raised 8 children, and worked as an auto mechanic. On examination, he had macrocephaly and mild macroorchidism but few of the other typical physical findings of males with fragile X syndrome. His Full Scale IQ is 73, and his Vineland Adaptive Behavior Composite is 73. On the Woodcock-Johnson Psycho-Educational Battery-Revised, he achieved standard scores of 64 in Reading, 55 in Math, and 83 in Knowledge. His DNA findings showed a broad smear on Southern blot analysis of 100-500 CGG repeats and no methylation at the EagI site upstream of the FMR-1 protein coding region. His FMR-1 protein production is 12% of normal. His daughters all have large premutations, with somatic instability in the size of the CGG repeat lengths. They all have evidence of academic underachievement and 2 have physical characteristics frequently described in individuals with fragile X. 21 refs., 3 figs.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
By: Product Area May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 View History Fuel Ethanol 29,666 29,684 30,256 29,621 28,543 30,139 1981-2015 Methyl Tertiary Butyl Ether (MTBE) 1,634...
Status and Impacts of State MTBE Bans
Reports and Publications (EIA)
This paper describes legislation passed in 16 states banning or restricting the use of methyl tertiary butyl ether (MTBE) in gasoline. Analysis of the status and impact of these state MTBE bans is provided concerning the supply and potential price changes of gasoline.
Motor Gasoline Outlook and State MTBE Bans
Reports and Publications (EIA)
The U.S. is beginning the summer 2003 driving season with lower gasoline inventories and higher prices than last year. Recovery from this tight gasoline market could be made more difficult by impending state bans on the blending of methyl tertiary butyl ether (MTBE) into gasoline that are scheduled to begin later this year.
Impact of Renewable Fuels Standard/MTBE Provisions of S. 1766
Reports and Publications (EIA)
This service report addresses the Renewable Fuels Standard (RFS)/methyl tertiary butyl ether (MTBE) provisions of S. 1766. The 'S. 1766' Case reflects provisions of S. 1766 including a renewable fuels standard (RFS) reaching five billion gallons by 2012, a complete phase-out of MTBE within four years, and the option for states to waive the oxygen requirement for reformulated gasoline (RFG).
Eliminating MTBE in Gasoline in 2006
Reports and Publications (EIA)
A review of the market implications resulting from the rapid change from methyl tertiary butyl ether (MTBE) to ethanol-blended reformulated gasoline (RFG) on the East Coast and in Texas. Strains in ethanol supply and distribution will increase the potential for price volatility in these regions this summer.