Search Results
Results 201 - 250 of 2320
< 1 2 3 4 5 6 7 8 9 10 >
Hattori Ryota - - 2011
Compound-specific carbon isotope analysis of acetic acid is useful for origin discrimination and quality control of vinegar. Intramolecular carbon isotope distributions, which are each carbon isotope ratios of the methyl and carboxyl carbons in acetic acid molecule, may be required to obtain more detailed information to discriminate such origin. In ...
Huynh Lien-Huong - - 2011
Neutral lipid from activated sludge (AS) as a potential source for biodiesel production has recently received considerable attentions. The utilization of useful compounds in AS may help reducing the cost of biodiesel production from AS. One of these compounds is the valuable wax esters (WEs) found in AS from a ...
Xie Wenlei - - 2011
The transesterification of soybean oil with methanol was carried out, to produce biodiesel, over silica-bonded N-propyl sulfamic acid in a heterogeneous manner. Results showed that a maximum conversion of 90.5% was achieved using a 1:20M ratio of soybean oil to methanol and a catalyst amount of 7.5wt.% at 423K for ...
Cooper George - - 2011
Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any ...
Nakajima Ken-Ichiro - - 2011
Neoculin, a sweet protein found in the fruit of Curculigo latifolia, has the ability to change sourness into sweetness. Neoculin turns drinking water sweet, indicating that non-acidic compounds may induce the sweetness. We report that ammonium chloride and certain amino acids elicit the intense sweetness of neoculin. Neoculin can thus ...
Spijkerman Elly - - 2011
The extremophilic microalga Chlamydomonas acidophila inhabits very acidic waters (pH 2-3.5), where its growth is often limited by phosphorus (P) or colimited by P and inorganic carbon (CO(2)). Because this alga is a major food source for predators in acidic habitats, we studied its fatty acid content, which reflects their ...
Chindapan Nathamol - - 2011
Fish sauce is an ingredient that exhibits unique flavor and is widely used by people in Southeast Asia. Fish sauce, however, contains a significant amount of salt (sodium chloride). Recently, electrodialysis (ED) has been successfully applied to reduce salt in fish sauce; however, no information is available on the effect ...
Kim Hakryul - - 2011
Microbial conversions of the unsaturated fatty acids often generate polyhydroxy fatty acids rendering them to have new properties such as higher viscosity and reactivity. A bacterial strain Pseudomonas aeruginosa (PR3) has been intensively studied to produce mono-, di-, and tri-hydroxy fatty acids from different 9-cis-monoenoic fatty acids such as oleic ...
Mahshid Sara - - 2011
The present work describes sensing application of modified TiO2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube ...
Grąz Marcin - - 2011
Efficient ligninolytic systems of wood-degrading fungi include not only oxidizing enzymes, but also low-molecular-weight effectors. The ability of Bjerkandera fumosa to secrete oxalic acid and versatile peroxidase (VP) in nitrogen-rich and nitrogen-limited media was studied. Higher activity of VP was determined in the nitrogen-limited media but greater concentration of oxalic ...
Yang Hui - - 2011
A new type of chiral beta-amino acid catalyst has been designed computationally mimicking the enzyme catalysis of serine proteases. Our catalyst approach is based on the bio-inspired catalytic acid-base dyad, namely carboxyl and imidazole pair. DFT calculations predict that this designed organocatalyst catalyzes Michael additions of aldehydes to nitroalkenes with ...
Lee Yong-Jae - - 2011
Most studies of linoleic acid biohydrogenation propose that it converts to stearic acid through the production of cis-9 trans-11 CLA and trans-11 C18:1. However, several other CLA have been identified in ruminai contents, suggesting additional pathways may exist. To explore this possibility, this research investigated the linoleic acid biohydrogenation pathway ...
Vyssotski M - - 2011
A Gram-negative, aerobic, pink-pigmented, rod-shaped bacterium Chthonomonas calidirosea (strain T49(T)) with an optimal temperature for growth of 68 °C, isolated from soil samples from Hell's Gate in the Tikitere geothermal system (New Zealand), was the first cultivated bacterium of the novel phylum Armatimonadetes (formerly candidate division OP10). The lipid composition of ...
Jaremko Matt - - 2011
Levulinic acid or 4-ketovaleric acid is a potential renewable substrate for production of polyhydroxyalkanoates. In this work, the initial reactions of LA metabolism by Cupriavidus necator were examined in vitro. The organic acid was converted by membrane-bound crude enzymes obtained from the cells pre-grown on LA, while no LA activity ...
Tan Yixin - - 2011
This investigation examined the effects of nitrogen-phosphate combined deficiency on the biomass yield, fatty acid methyl esters (FAME) production and composition from Scenedesmus rubescens-like microalga. A 15-day indoor culture was performed as a 3×3 factorial design (NaNO(3) levels: 3, 10 and 20mM; KH(2)PO(4) levels: 20, 50 and 150μM). The algae ...
Liu Yuan - - 2011
Escherichia coli strain NZN111 could convert glucose to succinic acid efficiently in anaerobic conditions after the induction of gluconeogenic carbon sources in aerobic conditions. Acetate shows a strong effect on both yield and productivity of succinic acid. In this study, the fed-batch process of succinic acid production by NZN111 using ...
Kong Hyesik - - 2011
N-aromatic acyl-amino acid conjugates possess a colon-targeted property, implying that such conjugates are stable and are not absorbable until reaching the large intestine in which they are microbially converted (hydrolysed) to the parent drugs that are therapeutically active. To investigate the structural effect of N-aromatic acyl-amino acid conjugates on the ...
Ganesan Aravindhan - - 2011
Effects of alkyl side chains (R-) on the electronic structural properties of aliphatic amino acids are investigated using quantum mechanical approaches. The carbon (C 1s) binding energy spectra of the aliphatic amino acids are derived from the C 1s spectrum of glycine (the parent spectrum) by the addition of spectral ...
Prakash Dhan - - 2011
The organism Acinetobacter sp. RKJ12 is capable of utilizing 2-chloro-4-nitrobenzoic acid (2C4NBA) as a sole source of carbon, nitrogen, and energy. In the degradation of 2C4NBA by strain RKJ12, various metabolites were isolated and identified by a combination of chromatographic, spectroscopic, and enzymatic activities, revealing a novel assimilation pathway involving ...
Mialon Laurent - - 2011
Polyalkylenehydroxybenzoates (PAHBs) are a new class of thermoplastic, biorenewable aromatic/aliphatic polyester having the general formula H-[O-(CH(2) )(n) -O-4-(3-X, 5-Y-C(6) H(2) )-CO](z) -OH. These are synthesized from the lignin-derived aromatics 4-hydroxybenzoic acid (X = Y = H), vanillic acid (X = OMe; Y = H), and syringic acid (X = Y = OMe). Alkylation of these with several chloroalkanols affords hydroxy-acid monomers suitable ...
Xue Feng - - 2011
A new class of readily available and easily tunable benzene backbone-based olefin-sulfoxide ligands was developed for the rhodium-catalyzed asymmetric conjugate addition reaction of arylboronic acids to enones with up to 97% yield and 97% ee.
Wurtman Richard J - - 2011
Nutrients are generally conceived as dietary substances which the body requires more-or-less continuously, within a particular dosage range, to protect against developing the characteristic syndromes that occur when they are deficient. However some nutrients - when given apart from their usual food sources or at higher doses than those obtained ...
Morales Gabriel - - 2011
Different lipidic wastes and low-grade oils and fats have been characterized and evaluated as feedstocks for the acid-catalyzed production of FAME. The characterization of these materials has revealed significant contents of free fatty acids, Na, K, Ca, Mg, P, unsaponifiable matter and humidity. Arenesulfonic acid-functionalized SBA-15 silica catalyst has provided ...
Stockton Amanda M - - 2011
Abstract The oxidizing surface chemistry on Mars argues that any comprehensive search for organic compounds indicative of life requires methods to analyze higher oxidation states of carbon with very low limits of detection. To address this goal, microchip capillary electrophoresis (μCE) methods were developed for analysis of carboxylic acids with ...
Geilen Frank Manfred Albert - - 2011
Selective hydrogenation of biogenic carboxylic acids is an important transformation for biorefinery concepts based on platform chemicals. We herein report a mechanistic study on the homogeneously ruthenium/phosphine catalyzed hydrogenation of levulinic acid (LA) and itaconic acid (IA) to the corresponding lactones, diols and cyclic ethers. A density functional theory (DFT) ...
Jankovic B - - 2011
Flowering plants, angiosperms, can be divided into two major clades, monocots and dicots, and while differences in amino acid composition in different species from the two clades have been reported, a systematic analysis of amino acid content and distribution remains outstanding. Here, we show that monocot and dicot proteins have ...
Karaman Rafik - - 2012
Based on stability studies on the drugs atenolol and propranolol and some of their derivatives it is believed that increasing the lipophilicity of the drug will lead to an increase in the stability of its aqueous solutions and will provide a prodrug system with the potential for releasing atenolol in ...
Han Jie - - 2011
The title compound, C(9)H(9)ClN(2), was prepared from the reaction of N-methyl-benzene-1,2-diamine and 2-chloro-acetic acid in boiling 6 M hydro-chloric acid. The benzimidazole unit is approximately planar, the largest deviation from the mean plane being 0.008 (1) Å. The Cl atom is displaced by 1.667 (2) Å from this plane. The methyl group is statistically ...
Souza Bruno S - - 2011
Hydrolysis of alkyl 1,8-naphthalic acid monoesters 1a-d is subject to highly efficient intramolecular nucleophilic catalysis by the neighboring COOH group. The reactivity for the COOH reaction depends on the leaving group pK(a), with values of β(LG) of -0.50, consistent with a mechanism involving rate determining breakdown of tetrahedral addition intermediates. ...
Bleif Sabrina - - 2011
The use of cytochromes P450 for the regio- and stereoselective hydroxylation of non-activated carbon atoms in biotechnological applications reflects an efficient and cost-effective alternative in comparison to classical organic chemistry. The prokaryotic cytochrome P450 CYP106A2 from Bacillus megaterium ATCC 13368 hydroxylates a variety of 3-oxo-Δ(4) steroids and recently it was ...
Khayoon M S - - 2011
Oxygenated fuel additives can be produced by acetylation of glycerol. A 91% glycerol conversion with a selectivity of 38%, 28% and 34% for mono-, di- and triacetyl glyceride, respectively, was achieved at 120°C and 3h of reaction time in the presence of a catalyst derived from activated carbon (AC) treated ...
Bhargava B L - - 2011
The reversible decomposition of formic acid (HCOOH ⇌ CO(2) + H(2)) has been attracting attention for its potential utility in hydrogen storage and production. It is therefore of interest to explore the influence of solvents on the decomposition reaction. To this end, Born-Oppenheimer (BO) molecular dynamics (MD) calculations have been ...
Watt Eric D - - 2011
Rate-limiting millisecond motions in wild-type (WT) Ribonuclease A (RNase A) are modulated by histidine 48. Here, we incorporate an unnatural amino acid, thia-methylimidazole, at this site (H48C-4MI) to investigate the effects of a single residue on protein motions over multiple timescales and on enzyme catalytic turnover. Molecular dynamics simulations reveal ...
Chandrashekar B N - - 2011
l-arginine was electropolymerised on a carbon paste electrode (CPE) to form the biopolymer by free radical formation in the electro oxidation process of the amino and carboxylic group containing compound by cyclic voltammetric technique. The modified electrode shows an excellent electrocatalytic activity towards the oxidation of both dopamine (DA) and ...
Emmett Michael R - - 2011
The reaction of cyclopropanes, geminally disubstituted with one carboalkoxy and one carbohydroxy group, undergoes ring-opening reactions with indole nucleophiles under catalyst-free, hyperbaric (13 kbar) conditions. An internal hydrogen bond is postulated as the mode of activation obviating the need for the Lewis acid catalyst normally used for such donor-acceptor cyclopropane ...
Gong Feiyan - - 2011
Light olefins are the basic building blocks for the petrochemical industry. In this work, selective production of light olefins from catalytic cracking of bio-oil was performed by using the La/HZSM-5 catalyst. With a nearly complete conversion of bio-oil, the maximum yield reached 0.28±0.02kg olefins/(kg bio-oil), which was close to that ...
Betz Richard - - 2011
Comparable to many amino acids, the title compound, C(6)H(5)NO(3), is a substitution product of picolinic acid. The mol-ecule shows approximate non-crystallographic C(s) symmetry. Like many amino acids, the mol-ecule is present in its zwitterionic state. Intra- as well as inter-molecular hydrogen bonds are observed, the latter connecting the mol-ecules into ...
Hansel Fabricio A - - 2011
A methodology is presented for the determination of dihydroxy fatty acids preserved in the 'bound' phase of organic residues preserved in archaeological potsherds. The method comprises saponification, esterification, silica gel column chromatographic fractionation, and analysis by gas chromatography/mass spectrometry. The electron ionisation mass spectra of the trimethylsilyl ether methyl ester ...
Ricochon Guillaume - - 2011
Aqueous extraction of sunflower seeds and rapeseeds with mixtures of hydrolytic enzymes were carried out in 2-L reactor and uronic acid and reducing sugar concentrations were measured during digestion. The goal of the study was to determine if a correlation between those concentrations and free oil exists that would allow ...
Bonacci Gustavo - - 2011
Nitro-fatty acids are electrophilic signaling mediators formed in increased amounts during inflammation by nitric oxide and nitrite-dependent redox reactions. A more rigorous characterization of endogenously-generated species requires additional understanding of their gas-phase induced fragmentation. Thus, collision induced dissociation (CID) of nitroalkane and nitroalkene groups in fatty acids were studied in ...
Zhu Qingjun - - 2011
A series of boron- and aluminium-containing MFI zeolites were synthesized and various characterization techniques, such as NMR ((27)Al, (29)Si and (11)B), were employed to study the acidities of zeolites. Moreover, in situ IR was applied to investigate the interaction of methanol and ethene with the acid sites, and those catalytic ...
Ding Mingliang - - 2011
Enzymatic hydrolytic degradation of polybutylene succinate (PBS), poly(polybutylenesuccinate-co-1,4-cyclohexane dimethanol) (PBS/CHDM) and poly(polybutylene succinate-co-diglycolic acid) (PBS/DGA) in mixed solvent of tetrahydrofuran (THF) and toluene was examined. Lipase was used as catalyst to degrade polymers with molecular weight of more than 100,000, and the molecular weight of products ranged from hundreds to ...
Notsu Keiji - - 2011
β-Substituted α-fluoro-α,β-unsaturated carboxylic acids have been successfully synthesized, usually in a (Z)-stereospecific manner by way of a stepwise or a one-pot three-step procedure starting from 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), one of the major byproducts of the industrial process for tetrafluoroethene formation from chlorofluoromethane (HCFC-22).
Amorim Madeira Paulo J - - 2011
Some antioxidant mechanisms displayed by several phenolic compounds relate with OH bond dissociation energy. One way for its determination, in the gas-phase, relies on acidity measurements. Gas-phase acidities were determined experimentally, applying the kinetic method, for chromanol and four dimethoxyphenols, and theoretically through quantum chemical DFT calculations for chromanol, six ...
Warren Charles R - - 2011
Phosphorus (P) has multiple effects on plant metabolism, but there are many unresolved questions especially for evergreen trees. For example, we do not know the general effects of P on metabolism, or if P affects photosynthesis via the internal conductance to CO(2) transfer from sub-stomatal cavities to chloroplast or amounts ...
Headley John V - - 2011
There is growing interest in the mass spectrometric characterization of oil sands acids present in natural waters and contaminated soils. This interest stems from efforts to isolate the principal toxic components of oil sands acid extractable organics in aquatic environment. Salting-out effects are demonstrated for nanospray ionization mass spectra of ...
Hu Hongjun - - 2011
A strain of the cyanobacterium Arthrospira was isolated from Lake Chahannaoer in northern China and was characterized according to microscopic morphology, photosynthetic oxygen-evolving activity, growth rate, and nutritional profile. Compared with thermophilic Arthrospira species occurring naturally in tropical and subtropical lakes, this isolate is mesophilic and grows optimally at ~20 ...
Yuan Xufeng - - 2011
A composite microbial system (XDC-2) was used to pretreat and hydrolyze corn stalk to enhance anaerobic digestion. The results of pretreatment indicated that sCOD concentrations of hydrolysate were highest (8,233 mg/l) at the fifth day. XDC-2 efficiently degraded the corn stalk by nearly 45%, decreasing the cellulose content by 22.7% ...
Fontaneto Diego - - 2011
Edible insects may be a source of long-chain polyunsaturated fatty acids (LC-PUFA). The aim of this article is to test for differences in aquatic and terrestrial insects used in human nutrition. We implemented linear models and discovered that differences in the proportion of LC-PUFA between aquatic and terrestrial insects do ...
Henden Emur - - 2011
Glazed and non-glazed earthenware is traditionally and widely used in Turkey and most of the Mediterranean and the Middle East countries for cooking and conservation of foodstuff. Acid-leaching tests have been carried out to determine whether the use of glazed and non-glazed earthenware may constitute a human health hazard risk ...
< 1 2 3 4 5 6 7 8 9 10 >