Search results for "Propane"
showing 10 items of 486 documents
Spectrophotometric determination of vitamin C using the copper(II)-nioxime-ascorbic acid system following stabilization in a propylene glycol medium
1989
Abstract A spectrophotometric method for the determination of Vitamin C is proposed. The procedure is based on formation and stabilization of the ternary complex Cu(II)-nioxime-ascorbic acid in 80% ( v v ) propylene glycol-water medium. The method has a high degree of tolerance for the determination of ascorbic acid in the presence of other active substances or excipients likely to be present along with vitamin C in pharmaceutical formulations. The suggested method has proved to be rapid and precise and has been successfully applied to different commercial pharmaceutical preparations of vitamin C. Precision, measured on the relative standard deviation, did not exceed 0.73%.
Stress Responses of Oenococcus oeni
2011
Oenococcus oeni is an alcohol-tolerant, acidophilic lactic acid bacterium responsible for malolactic fermention in wine. The stress responses of O. oeni have been studied at both the molecular and physiological levels. Genes encoding stress proteins mainly belong to the CtsR regulon. Other regulation mechanisms seem to coexist in O. oeni and may correspond to posttranscriptional regulation. Maintenance of the cell membrane integrity under stress conditions seems to be a prerequisite for survival in wine. The active cell response to protect membrane function under stress conditions requires changes in fatty acid composition and involves stress proteins. Various solute transporters and energy…
Structural characterization of 2,2-di-n-butyl-4-methyl-1,3,2-dioxastannolane isolated from supercritical CO2 conditions
2009
The title compound has been isolated as single crystals from the synthesis of propylene carbonate from racemic 1,2-propanediol and carbon dioxide using n-Bu2SnO as a catalyst precursor. The X-ray crystallographic structure analysis revealed the self-assembly of di-n-butyltin(IV) 1,2-propanediolate units, linked together through long-distance Sn-O interactions leading to a one-dimensional polymeric architecture organized in a syndiotactic arrangement. The coordination geometry around the tin atoms can be described as an unusual faced-capped trigonal bipyramidal environment.
Cyclopropane Fatty Acid Synthase from Oenococcus oeni: Expression in Lactococcus lactis subsp. Cremoris and Biochemical Characterization
2015
Bacterial cyclopropane fatty acid synthases (CFA synthases) catalyze the transfer of a methyl group from S-adenosyl-L-methionine (AdoMet) to the double bond of a lipid chain, thereby forming a cyclopropane ring. CFAs contribute to resistance to acidity, dryness, and osmotic imbalance in many bacteria. This work describes the first biochemical characterization of a lactic acid bacterium CFA synthase. We have overexpressed Oenococcus oeni CFA synthase in E. coli in order to purify the enzyme. The optimum cyclopropanation activity was obtained at pH 5.6 and 35.8 °C. The high K(m) (AdoMet) value obtained (2.26 mM) demonstrates the low affinity of O. oeni enzyme toward the L. lactis subsp. cremo…
CCDC 278947: Experimental Crystal Structure Determination
2006
Related Article: Z.Halime, S.Balieu, M.Lachkar, T.Roisnel, P.Richard, B.Boitrel|2006|Eur.J.Org.Chem.|2006|1207|doi:10.1002/ejoc.200500685
The effects of biomass co-gasification and co-firing on the development of combustion dynamics
2018
Abstract Effects of wheat straw co-firing with gas (propane flame) and co-gasification/co-combustion with wood pellets on the development of thermo-chemical conversion of biomass pellets and on heat energy production were experimentally studied and analyzed with the aim to improve the gasification/combustion characteristics and the applicability of wheat straw as an alternative energy source for cleaner heat energy production. The results suggest that the wheat straw co-firing with propane provides an enhanced thermal decomposition of pellets with more complete combustion of volatiles increasing thus the heat output at thermo-chemical conversion of wheat straw and the produced heat energy p…
Propanediol-1,2-dehydratase and metabolism of glycerol of Lactobacillus brevis
1984
While most strains of heterofermentative lactobacilli and strains of Leuconostoc species contained only traces of a dehydratase reacting with glycerol or propanediol-1,2, three strains of Lactobacillus brevis and one strain of L. buchneri that metabolized glycerol readily in the presence of glucose, contained propanediol-1,2 dehydratase (EC 4.2.1.28). This cobamide requiring enzyme from L. brevis B 18 was partially purified. It reacts with the substrates propanediol-1,2, glycerol and ethanediol-1,2 with the relative activities of about 3:2:1. This ratio remained unchanged throughout the purification procedure. The substrate affinities were measured: propanediol-1,2 K m=0.6 mM, glycerol K m=…
CCDC 864209: Experimental Crystal Structure Determination
2012
Related Article: R.W.Troff, R.Hovorka, T.Weilandt, A.Lutzen, M.Cetina, M.Nieger, D.Lentz, K.Rissanen, C.A.Schalley|2012|Dalton Trans.|41|8410|doi:10.1039/c2dt30190c
CCDC 864207: Experimental Crystal Structure Determination
2012
Related Article: R.W.Troff, R.Hovorka, T.Weilandt, A.Lutzen, M.Cetina, M.Nieger, D.Lentz, K.Rissanen, C.A.Schalley|2012|Dalton Trans.|41|8410|doi:10.1039/c2dt30190c
CCDC 1059034: Experimental Crystal Structure Determination
2015
Related Article: Z. Setifi, A. Valkonen, M.A. Fernandes, S. Nummelin, H. Boughzala, F. Setifi, C. Glidewell|2015|Acta Crystallogr.,Sect.E:Cryst.Commun.|71|509|doi:10.1107/S2056989015007306