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Results 201 - 250 of 3174
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Liu Jia J Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, - - 2012
Site-specific incorporation of unnatural amino acids into proteins in vivo relies on the genetic reassignment of nonsense or quadruplet codons. Here, we describe a general procedure for the random introduction of these codons into open reading frames resulting in protein libraries that are scanned with unnatural amino acid residues. These ...
Duong Cindy T - - 2011
Free fatty acid (FFA) compositions are examined in feedstock for biodiesel production, as source-specific markers in soil, and because of their role in cellular signaling. However, sample preparation of FFAs for gas chromatography-mass spectrometry (GC-MS) analysis can be time and labor intensive. Therefore, to increase sample preparation throughput, a glass ...
Denmark Scott E - - 2012
A binary catalyst system for the enantioselective bromocycloetherification of 5-arylpentenols is described. The combination of an achiral Lewis base and a chiral Brønsted acid affords good enantioselectivities for the cyclization of Z configured 5-arylpentenols to form bromomethyltetrahydrofurans. The constitutional site selectivity is highly dependent upon the aromatic substituent and the ...
van den Broek Bas A M W - - 2011
Epoxidation of both terminal and non-terminal olefins with peroxy acids is a well-established and powerful tool in a wide variety of chemical processes. In an additional step, the epoxide can be readily converted into the corresponding trans-diol. Batch-wise scale-up, however, is often troublesome because of the thermal instability and explosive ...
Noha Stefan M - - 2012
The release of arachidonic acid, a precursor in the production of prostaglandins and leukotrienes, is achieved by activity of the cytosolic phospholipase A(2)α (cPLA(2)α). Signaling mediated by this class of bioactive lipids, which are collectively referred to as eicosanoids, has numerous effects in physiological and pathological processes. Herein, we report ...
Huang Jeff - - 2011
Generation of process waters contaminated by naphthenic acids is a serious environmental concern associated with processing of the oil sands. This together with the necessity for sustainable use of water highlights the need for development of effective technologies such as bioremediation for treatment of these contaminated waters. In this work, ...
Higuera Gustavo A - - 2012
The nutritional requirements of stem cells have not been determined; in particular, the amino acid metabolism of stem cells is largely unknown. In this study, we investigated the amino acid metabolism of human mesenchymal stem cells (hMSCs), with focus on two questions: Which amino acids are consumed and/or secreted by ...
Dhami Manpreet K - - 2011
The quantity and chemical composition of honeydew produced by scale insects may influence wider community structure, but little is known about the detailed chemical composition of the honeydew found in forest ecosystems. We used gas chromatography-mass spectrometry to examine the amino acid and carbohydrate composition of honeydew from three New ...
Kandra Prameela - - 2011
The production of shrimp waste from shrimp processing industries has undergone a dramatic increase in recent years. Continued production of this biomaterial without corresponding development of utilizing technology has resulted in waste collection, disposal, and pollution problems. Currently used chemical process releases toxic chemicals such as HCl, acetic acid, and ...
Wada Yusuke - - 2011
In this study, a high-throughput and high-sensitivity profiling system for β-cryptoxanthin (βCX) and β-cryptoxanthin fatty acid ester (βCXFA) was constructed by supercritical fluid chromatography (SFC) coupled with triple quadrupole mass spectrometry (QqQMS). βCX and nine βCXFAs were successfully separated within 20 min using a column packed with octadecylsilyl-bonded silica particles. The ...
Rodriguez-Granillo Agustina - - 2011
Judicious incorporation of D-amino acids in engineered proteins confers many advantages such as preventing degradation by endogenous proteases and promoting novel structures and functions not accessible to homochiral polypeptides. Glycine to D-alanine substitutions at the carboxy termini can stabilize α-helices by reducing conformational entropy. Beyond alanine, we propose additional side ...
Sankaranarayanan Kamatchi - - 2011
The viscosity of amino acids enclosed in giant lipid vesicles (η(out)) subjected to a shear flow near a solid surface has been studied using quartz crystal microbalance (QCM). This viscosity has been compared with shear viscosity for the different amino acids adsorbed on supported bilayers (SLBs) (η(in)) of the lipids ...
Swartz Joshua David - - 2011
An antibody-free diagnostic reagent has been developed based on the aggregation-induced colorimetric change of Ni(II)NTA functionalized colloidal gold and silver nanoparticles. This diagnostic strategy utilizes the high binding affinity of histidine-rich proteins with Ni(II)NTA to capture and crosslink the histidine-rich protein mimics with the silver and gold nanoparticles. In model ...
Calandra Pietro - - 2011
The physico-chemical properties of Bis(2-ethylhexyl)amine (BEEA) plus octanoic acid (OA) mixtures have been investigated by IR, SAXS, WAXS, viscosimetry, and AC complex impedance spectroscopy in the whole composition range. Mainly driven by proton transfer from the acidic OA to the basic BEEA, the formation of stoichiometrically well-defined adducts takes place ...
Hoff Lars - - 2011
The ultrasound contrast agents Echovist(®) and Levovist(®) (Bayer AG, Schering AG, Germany) are based on the release of gas bubbles from milled α-d-galactose. In diagnostic ultrasound, for this class of contrast agents, there is a need for prolonged contrast duration. To investigate if new carbohydrate compositions could prolong the lifetime ...
Urban Jiri - - 2012
An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the ...
Smaltz Daniel J DJ Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United - - 2011
An efficient four-step synthetic route to the useful chiral building block (2R,3S)-dihydroxybutyric acid acetonide in >95% ee is detailed. The sequence is readily scaled, requires no chromatography, and allows for efficient recycling of p-phenylbenzyl alcohol, an expedient for enantio- and diastereoenrichment by recrystallization.
Bergmann M E Henry - - 2011
Regeneration of spent accumulator acid could be an alternative process for crystallization, neutralisation and disposal. Therefore, for the first time in a study of the possibilities of electrochemical removal of antimony and accumulator acid regeneration on a laboratory scale, two synthetic and several real systems containing sulfuric acid of concentrations ...
Moloudi Rohallah - - 2011
Gastro-esophageal reflux currently is widespread disorders with dangerous complications. GLP-2 is a peptide that has trophic and anti-inflammatory effects on gastrointestinal mucosa. The aim of this study was to evaluate the protective role of GLP-2 in esophageal mucosa lesion due to perfusion acid-pepsin. Thirty-six male rats were used in this ...
Draelos Zoe Diana - - 2011
Background  A variety of prescription devices have been developed to improve barrier function in persons with atopic dermatitis. These products are based primarily on the use of occlusive agents to decrease transepidermal water loss, creating an environment for optimal healing. Aim  A newly developed hyaluronic acid based, pH neutral foam ...
Ding Shangjun - - 2011
Amino acids, as a particularly important type of biomolecules, have been used as multifunctional templates to intelligently construct mesoporous TiO(2) hollow structures through a simple solvothermal reaction. The structure-directing behaviors of various amino acids were systematically investigated, and it was found that these biomolecules possess the general capability to assist ...
Kuster S - - 2011
Buoyancy-driven hydrodynamic instabilities of acid-base fronts are studied both experimentally and theoretically in the case where an aqueous solution of a strong acid is put above a denser aqueous solution of a color indicator in the gravity field. The neutralization reaction between the acid and the color indicator as well ...
Uchinashi Yosuke - - 2011
Despite the previous literature describing the "low-to-modest" efficiency, the readily available C5-acetamide donor was reinvestigated for its use in α-sialylation under microfluidic conditions. The N-phenyltrifluoroacetimidate donor was efficiently mixed with an appropriate amount of TMSOTf to produce the α(2-6) and α(2-3)-sialylation products of galactose and glucosamine acceptors in excellent yields ...
Pandya Bhaumik A - - 2011
Orthogonally protected chiral β-hydroxy-γ-amino acids can be accessed in >100 g quantities from readily available starting materials and reagents in 3-4 steps. These chiral synthons contain two adjacent stereocenters along with suitably protected functional groups (O-TBS, N-Boc) for downstream reactivity. Implementation of two existing aldol technologies allows rapid access to ...
Guo Xia - - 2012
Gene therapy has long been regarded a promising treatment for many diseases, whether acquired (such as AIDS or cancer) or inherited through a genetic disorder. A drug based on a nucleic acid, however, must be delivered to the interior of the target cell while surviving an array of biological defenses ...
De Michelis Ida - - 2011
The paper deals with recovery of yttrium from fluorescent powder coming from dismantling of spent fluorescent tubes. Metals are leached by using different acids (nitric, hydrochloric and sulphuric) and ammonia in different leaching tests. These tests show that ammonia is not suitable to recover yttrium, whereas HNO(3) produces toxic vapours. ...
Ahlström Christine - - 2011
In this paper we quantitatively evaluate two feedback systems with a focus on rate and extent of tolerance and rebound development. In the two feedback systems, the regulation of turnover of response is governed by one or several moderators. In the basic system, one single moderator inhibits the formation of ...
Li Dong-Mi - - 2011
A new chiral fluorescence receptor, designed to exploit aggregation-induced emission (AIE), exhibited not only an exceptionally high enantioselectivity but was also applicable to a wide range of chiral carboxylic acids. The fluorescence intensity ratio of two enantiomers ranged from 10 to 1.6 × 10(4) and could be used to determine ...
Eaton Joseph W - - 2011
PURPOSE: To evaluate salicylic acid tablets as a candidate reference material in a Performance Verification Test (PVT) when a USP performance test for dissolution (General Chapter <711>) relies on USP Apparatus 4 (flow-through cell). METHODS: We developed a dissolution procedure relying on Apparatus 4 and salicylic acid tablets. Thereafter, a ...
Amaral Sandra P - - 2011
A multigram synthesis of the repeating unit of GATG (gallic acid-triethylene glycol) dendrimers is described through an efficient and cost-effective route. These conditions overcome major problems precluding scaling up and afford product in excellent overall yield and purity. Special attention has been paid in this process to green chemistry principles: ...
Hayyan Adeeb - - 2011
An industrial grade acidic crude palm oil (ACPO) pre-treatment process was carried out using ethanesulfonic acid (ESA) as a catalyst in the esterification reaction. ESA was used in different dosages to reduce free fatty acid (FFA) to a minimum level for the second stage of biodiesel production via alkaline transesterification ...
Zheng Anmin - - 2011
A brief review is presented on acidity characterization of solid acid catalysts by means of solid-state phosphor-31 magic-angle-spinning nuclear magnetic resonance ((31)P MAS NMR) spectroscopy using phosphor-containing molecules as probes. It is emphasized that such a simple approach using (31)P MAS NMR of adsorbed phosphorous probe molecules, namely trimethylphosphine (TMP) ...
Junne Stefan - - 2011
This study describes an advanced version of a two compartment scale-down bioreactor which simulates inhomogeneities present in large scale industrial bioreactors in the laboratory scale. The system is made of commercially available parts and is suitable for sterilization with steam. The scale-down bioreactor is comprised of a usual stirred tank ...
Ibrahim Medhat - - 2011
The molecular structure of gelatin was studied using Fourier transform infrared spectroscopy FTIR. The spectrum is subjected to deconvolution in order to elucidate the constituents of the molecular structure. B3LYP/6-31g** was used to study 13 amino acids then the scaled spectrum was compared to those of protein in order to ...
Xintian Zheng - - 2011
INTRODUCTION: Chinese herbal medicines contain complex ingredients that are unstable during the manufacturing process. Current off-line methods are usually time-consuming and inaccurate. OBJECTIVE: The aim of this study was to develop a continuous-flow-based on-line spectroscopic system for monitoring the degradation of unstable compounds in Chinese herbal medicines. METHODOLOGY: An on-line ...
Tretter Sandra - - 2011
Seven dogs with atopic dermatitis and six normal dogs were treated with a spot-on product containing essential oils and unsaturated fatty acids q 7 days for 8 wk. Seven additional atopic dogs received a daily spray containing similar ingredients to the spot-on. In all dogs, transepidermal water loss (TEWL) was ...
Ermini M L - - 2011
Development of nucleic acid-based sensing attracts the interest of many researchers in the field of both basic and applied research in chemistry. Major factors for the fabrication of a successful nucleic acid sensor include the design of probes for target sequence hybridization and their immobilization on the chip surface. Here ...
Zhang Huili - - 2011
Poly (β-L: -malic acid) (PMLA) is a water-soluble polyester with many attractive properties in chemical industry and medicine development. However, the low titer of PMLA in the available producer strains limits further industrialization efforts and restricts its many potential applications. In order to solve this problem, a new strain with ...
John T A - - 2011
The reduction of aggressive factors such as gastric acid is considered a key target of gastrointestinal protection. We investigated the antisecretory effect of the aqueous bark extract of E. utile, a Nigerian traditional medicinal preparation used for ulcers. Male rats were anesthetized and cannulated for intragastric perfusion of saline and ...
Hershcovici Tiberiu - - 2011
Eur J Clin Invest 2011 ABSTRACT: Background  Heartburn is commonly associated with the presence of acid in the oesophageal lumen. However, in patients with nonerosive reflux disease (NERD), the mechanism by which acid traverses the mucosa is not clear. We hypothesized that the luminal acid signal traverses the oesophageal epithelium ...
Banerjee Partha Sarathi - - 2011
Surface modification of adenovirus vectors can improve tissue-selective targeting, attenuate immunogenicity, and enable imaging of particle biodistribution, thus significantly improving therapeutic potential. Currently, surface engineering is constrained by a combination of factors, including impact on viral fitness, limited access to functionality, or incomplete control over the site of modification. Here, ...
Ritchie Jason E - - 2011
Proton conducting electrolytes composed of a mixture of MePEG7SO3H acid and a four-armed, PEG-based, Star molecule were prepared. Four MePEGn (n = 3, 7, 12) arms were attached to pentaerythritol or tetrakis(dimethylsilyl) orthosilicate core to form the Star Molecules. We have examined the structure of these Star electrolytes to observe ...
Christaki Efterpi - - 2011
Microalgae are known for centuries, but their commercial large-scale production started a few decades ago. They can be grown in open-culture systems such as lakes or highly controlled close-culture systems, have higher productivity than the traditional crops and can be grown in climatic conditions and regions where other crops cannot ...
Böttcher Christine - - 2011
Nine Gretchen Hagen (GH3) genes were identified in grapevine (Vitis vinifera L.) and six of these were predicted on the basis of protein sequence similarity to act as indole-3-acetic acid (IAA)-amido synthetases. The activity of these enzymes is thought to be important in controlling free IAA levels and one auxin-inducible ...
Barriuso Jorge - - 2011
Lovastatin, a cyclic nonaketide from Aspergillus terreus, is a hypercholesterolemic agent and a precursor to simvastatin, a semi-synthetic cholesterol-lowering drug. The biosynthesis of the lovastatin backbone (dihydromonacolin L) and the final 2-methylbutyryl decoration have been fully characterized. However, it remains unclear how two central reactions are catalyzed, namely, introduction of ...
Bengtsson Christoffer - - 2011
Inhibition of acetyl-CoA carboxylases has the potential for modulating long chain fatty acid biosynthesis and mitochondrial fatty acid oxidation. Hybridization of weak inhibitors of ACC2 provided a novel, moderately potent but lipophilic series. Optimization led to compounds 33 and 37, which exhibit potent inhibition of human ACC2, 10-fold selectivity over ...
Gomaa Mohamed S - - 2011
The synthesis and potent inhibitory activity of novel imidazole methyl 3-(4-(aryl-2-ylamino)phenyl)propanoates in a MCF-7 CYP26A1 microsomal assay is described. The induction of CYP26A1 mRNA was used to evaluate the ability of the compounds to enhance the biological effects of all-trans retinoic acid (ATRA) in a retinoid-responsive neuroblastoma cell line. The ...
Okamoto Masanori M RIKEN Plant Science Center, 1Tsurumi-ku, Yokohama, - - 2011
Abscisic acid (ABA) catabolism is important for regulating endogenous ABA levels. To date, most effort has focused on catabolism of ABA to phaseic acid (PA), which is generated spontaneously after 8'-hydroxylation of ABA by cytochrome P450s in the CYP707A subfamily. Neophaseic acid (neoPA) is another well-documented ABA catabolite that is ...
Oomah B Dave - - 2011
Thirteen low-tannin fava bean genotypes grown at two locations in north central Alberta in 2009 were evaluated to investigate the variation in seed characteristics, phenolic and phytate contents, and phytase and antioxidant activities and to elucidate the relationship of these components as a breeding strategy. Seed characteristics including color were ...
Cebolla-Cornejo Jaime - - 2011
Taste and aroma related compounds have been analyzed in a collection of four traditional varieties and two tomato hybrids, representing a wide variability in fruit shape and color, grown in different environments: screenhouse and open field. Protected cultivation tended to show lower sugar concentration (fructose and glucose) but similar acid ...
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