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Alcohol Used (alcohol + used)
Selected AbstractsSTUDY OF FACTORS INFLUENCING PROTEIN ESTERIFICATION USING ,-LACTOGLOBULIN AS A MODELJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2000MAHMOUD SITOHY ABSTRACT ,-Lactoglobulin was esterified with different alcohols (methanol, ethanol, n-propanol and iso-propanol) over various conditions of acidity, protein concentration, water content, time and temperature. The resulting products were simply recovered by centrifugation of the reaction mixture at the end of the reaction. Yield of esterification was markedly dependent on the concentration of the acid, of the protein, the water content and the type of alcohol used. Using ethanol andpropanol required 5 and 10% water, respectively to reach a maximum esterification degree. Concentrations of acid and protein were the crucial parameters. Protein concentration (4 or 5%) together with an adequate H+/COOH molar ratio, not only enhance the yield of esterification with ethanol but also increase the rate of this reaction. The results may be applicable to choosing the reaction conditions for the preparation of other esterified proteins. The conditions described in this study increase esterification reaction rate compared to that under conditions used traditionally. [source] Polymerization of 1,2:5,6-diepithio-3,4-di- O -methyl- D -mannitol, 1,2:5,6-diepithio-3,4-di- O -methyl- L -iditol, and 1,2:5,6-diepithio-3,4-di- O -methyl-allitol using zinc complexes: The regio- and stereoselectivities and asymmetric synthesis of thiosugar polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2005Toshifumi Satoh Abstract The polymerizations of the diepisulfides 1,2:5,6-diepithio-3,4-di- O -methyl- D -mannitol (1a), 1,2:5,6-diepithio-3,4-di- O -methyl- L -iditol (1b), and 1,2:5,6-diepithio-3,4-di- O -methyl-allitol (1c) were carried out with ZnEt2/H2O, ZnEt2/alcohol, and ZnEt2/(S or R)-1,1,-bi-2-naphthol (BN) as the initiator systems. All the polymerizations proceeded without any gel formation and gave white, powdery products. The number-average molecular weights of the obtained polymers were changed in the range of 5300,33,600. The polymerization of 1a using the ZnEt2/H2O (1/1) catalyst in tetrahydrofuran proceeded through a regio- and stereoselective cyclopolymerization mechanism to produce thiosugar polymers mainly consisting of 2,5-anhydro-1,5-dithio- D -glucitol as the five-membered ring units. The polymers obtained from 1b and 1c with ZnEt2/H2O exhibited lower stereoregularities than that from 1a. For the polymers obtained from 1a with the ZnEt2/alcohol systems, the molar fraction of the five-membered ring units depended on the alcohol used as a ligand. On the other hand, the polymerization of 1c using ZnEt2/(R or S)-BN asymmetrically proceeded, and optically active polymers consisting of desulfurized acyclic units were obtained. When ZnEt2/(R)-BN (1/1) was used in toluene, the polymer with [,]D23 = +56.9° was obtained in an 88.6% yield. The resulting polymer had an isotactic-rich structure consisting of about 90% (R)-configurational units and about 10% (S)-units. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4118,4125, 2005 [source] Findings Across Subgroups Regarding the Level of Response to Alcohol as a Risk Factor for Alcohol Use Disorders: A College Population of Women and LatinosALCOHOLISM, Issue 10 2004Marc A. Schuckit Background: The rates of alcohol dependence, a genetically influenced disorder, are increased among Latino men in the United States and are lower among women across ethnic groups. These analyses explored whether the differential rate of alcohol use disorders (AUDs) might reflect one genetically influenced phenotype related to alcoholism risk: the low level of response (LR) to alcohol. Methods: A questionnaire was mailed to students at two universities to identify drinking but not alcohol-dependent 18- to 29-year-old men and women who had a parent with alcohol dependence. Subjects were subsequently screened with a validated semistructured interview to corroborate the personal and family histories, and they participated in a challenge with alcohol 0.75 ml/kg for women and 0.90 ml/kg for men. LRs to alcohol were determined and compared between genders and between Latino versus Caucasian/Anglo subjects. Results: The data revealed no consistent significant differences between genders regarding either subjective feelings of intoxication or alcohol-induced changes in body sway. A similar lack of differential between groups was observed when Latino and Caucasian/Anglo subjects were compared. However, there was at least a statistical trend for interactions when gender, ethnicity, and time were considered together; there was some evidence for a higher LR in Latina women. Perhaps reflecting the different weights and doses of alcohol used, men demonstrated higher breath alcohol concentrations, but no differences in these values were noted between Latino and Anglo populations. Conclusions: The results indicate that the LR to alcohol is not likely to explain differences in rates of AUDs between genders or these two ethnic groups overall. The possibility that a higher LR might be seen for the subgroup with the lowest AUD rate,Latina women,will require replication in larger samples of well matched groups before definitive conclusions can be drawn. [source] Contact allergy caused by air oxidation of common materials , diagnosis and preventionCONTACT DERMATITIS, Issue 3 2004Ann-Therese Karlberg When considering the allergenic activity of a compound not only the possibility of bioactivation by skin metabolism but also air activation by autoxidation must be taken into account. Natural compounds (terpenes) easily oxidize at air exposure. They are found in products that are common causes of allergic contact dermatitis (ACD) i.e. colophony and fragrances. The introduction of oxygen enables the molecules to form antigens with skin proteins via a nucleophilic- electrophilic interaction or via a radical reaction. The latter mechanism seems to be important since the primary oxidation products, the hydroperoxides, are the most potent sensitizers formed. Oxidative decomposition at air exposure resulting in allergenic oxidation products is observed also for other common compounds e.g. ethoxylated fatty alcohols used as surfactants. It is important to test the patient with the offending compounds for diagnosis of ACD. A negative diagnosis can be due to failure in testing with the correct substances. In the case of air activated compounds, testing should not be performed with the pure substances but rather with the oxidation mixture or the most sensitizing oxidation products (the hydroperoxides). We have in multicenter-studies shown that the common fragrance terpenes, limonene and linalool, are frequent sensitizers when oxidized. This is a challenge in clinical practice since such patch test materials are not easily standardized. Compounds, easily activated at air exposure, should be prevented from oxidative decomposition by addition of antioxidants and proper handling and storage. More research is needed in this area. [source] Alcohols for the ,-Alkylation of Methyl Ketones and Indirect Aza-Wittig Reaction Promoted by Nickel Nanoparticles,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2008Francisco Alonso Abstract Nickel nanoparticles have been found to activate primary alcohols used for the ,-alkylation of ketones or in indirect aza-Wittig reactions. These processes involve hydrogen transfer from the alcohol to the intermediate ,,,-unsaturated ketone or imine, respectively. All these reactions are carried out in the absence of any ligand, hydrogen acceptor or base under mild reaction conditions. For the first time nickel is employed as a potential alternative to noble-metal-based catalysts in both reactions. A reaction mechanism is proposed on the basis of some deuteration experiments. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] | |||||||||||||