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Acid G (acid + g)
Selected AbstractsFirst Total Synthesis and Stereochemical Definition of Isodomoic Acid G.CHEMINFORM, Issue 6 2004Yike Ni No abstract is available for this article. [source] In Vitro Protective Effect of Hypericum androsaemum Extract Against Oxygen and Nitrogen Reactive SpeciesBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 4 2009Isabel F. Almeida Oxidative stress and nitrosative stress are common pathogenetic mechanisms contributing to initiation and progression of hepatic damage in several liver disorders. In the present study, an ethanol:water (4:6) extract from H. androsaemum branches and leaves were evaluated for its putative in vitro scavenging effects on 1,1-diphenyl-2-picrylhydrazil radical, on reactive oxygen species, namely HO,, O2,,, ROO,, 1O2 and H2O2 and on reactive nitrogen species, namely ,NO and ONOO,. The hypericum extract presented a remarkable capacity to scavenge all the tested reactive species, all the IC50 values being found at the ,g/ml level. IC50 values for 1,1-diphenyl-2-picrylhydrazil, and for the reactive oxygen species O2,,, H2O2, HO, and 1O2 were 11.3 ± 0.7, 32.7 ± 3.4, 944 ± 47, 595 ± 82, 28.3 ± 1.2 ,g/ml respectively. The oxygen radical absorbance capacity value obtained for ROO, was 1.5 ± 0.1 ,mol Trolox equivalents/mg extract. The IC50 values for ,NO and ONOO, were 2.2 ± 0.2 and 1.2 ± 0.1 ,g/ml respectively. The content of total phenolics was 281 ± 2 mg of gallic acid equivalents/g of lyophilized extract. The observed antioxidant activity provides scientific support for the reported therapeutic use of H. androsaemum, though further in vitro and in vivo studies are required to ascertain the risk/benefit score at therapeutic concentrations. [source] Fermentative production of L(+)-lactic acid from starch hydrolyzate and corn steep liquor as inexpensive nutrients by batch culture of Enterococcus faecalis RKY1JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2008Young-Jung Wee Abstract BACKGROUND: Attempts were made to determine the lactic acid production efficiency of novel isolate, Enterococcus faecalis RKY1 using four different starches (corn, tapioca, potato, and wheat starch) with different concentrations (50, 75, 100, and 125 g L,1) and corn steep liquor as an inexpensive nitrogen source. RESULTS: The yield of lactic acid from each starch was higher than 95% based on initial starch concentrations. High lactic acid concentration (129.9 g L,1) and yield (1.04 g-lactic acid g,1 -starch) were achieved faster (84 h) from 125 g L,1 of corn starch. Among the starches used, tapioca starch fermentation usually completed in a shorter incubation period. The final dry cell weight was highest (7.0 g L,1) for the medium containing 75 g L,1 of corn starch, which resulted in maximum volumetric productivity of lactic acid (3.6 g L,1 h,1). The addition of 30 g L,1 corn steep liquor supplemented with a minimal amount of yeast extract supported both cell growth and lactic acid fermentation. CONCLUSION:Enterococcus faecalis RKY1 was found to be capable of growing well on inexpensive nutrients and producing maximum lactic acid from starches and corn steep liquor as lower-cost raw materials than conventionally-used refined sugars such as glucose, and yeast extract as an organic nitrogen source in laboratory-scale studies. These fermentation characteristics are prerequisites for the industrial scale production of lactic acid. Copyright © 2008 Society of Chemical Industry [source] The effect of different carbon sources on the nutritional value of bioflocs, a feed for Macrobrachium rosenbergii postlarvaeAQUACULTURE RESEARCH, Issue 4 2010Roselien Crab Abstract A 15-day lab-scale experiment was performed to determine the possible use of bioflocs as a feed for Macrobrachium rosenbergii postlarvae. The bioflocs were grown on acetate, glycerol and glucose. A glycerol-fed reactor was initially inoculated with a Bacillus spores mixture. The highest protein content was obtained in the (glycerol+Bacillus) bioflocs, i.e. 58±9% dry weight (DW). The glycerol and acetate bioflocs showed a lower, but similar content (42,43% DW) and glucose bioflocs contained 28±3% DW. Higher total n-6 fatty acid contents were observed in the glycerol and (glycerol+Bacillus) bioflocs. The vitamin C content was variable, up to 54 ,g ascorbic acid g,1 DW in the glycerol bioflocs. Bioflocs were fed to M. rosenbergii postlarvae as the sole feed. High survival levels were obtained in the (glycerol+Bacillus) and glucose groups, i.e. 75±7% and 70±0% respectively. This was significantly higher than the starvation control (0% survival after 15 days). This indicated that the prawns were able to feed on the bioflocs. These results are in accordance with the biofloc's nutritional parameters and suggest that the choice of the carbon source used for growing bioflocs is of prime importance. [source] Polysulfone ionomers functionalized with benzoyl(difluoromethylenephosphonic acid) side chains for proton-conducting fuel-cell membranesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 2 2007Benoît Lafitte Abstract Polysulfones carrying benzoyl(difluoromethylenephosphonic acid) side chains were prepared and investigated for use as proton-conducting fuel-cell membranes. In the first step, polysulfones were lithiated and reacted with methyl iodobenzoates to prepare p - and o -iodobenzoyl polysulfones. Next, the phosphonated polysulfones were prepared via CuBr-mediated cross-coupling reactions between the iodinated polymer and [(diethoxyphosphinyl)difluoromethyl]zinc bromide. Finally, dealkylation with bromotrimethylsilane afforded highly acidic CF2PO3H2 derivatives. The replacement of the iodine atoms by CF2PO3Et2 units was almost quantitative in the case of o -iodobenzoyl polysulfone. Membranes based on ionomers having 0.90 mmol of phosphonic acid units/g of dry polymer took up 6 wt % water when immersed at room temperature, and conductivities up to 5 mS cm,1 at 100 °C were recorded. This level of conductivity was comparable to that reached by a membrane based on a sulfonated polysulfone having 0.86 mmol of sulfonic acid/g of dry polymer. Thermogravimetry revealed that the arylCF2PO3H2 arrangement decomposed at approximately 230 °C via cleavage of the CP bond. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 269,283, 2007. [source] | ||||||||||