Search Results
Results 51 - 100 of 1678
1 2 3 4 5 6 7 8 9 10 >
Magalhães Danielly de Paiva - - 2012
An image analysis biomonitoring system was used to evaluate sublethal effects of pH on the mean swimming velocity of zebrafish. Responses to stress were tested comparing individual and group responses. Group analysis indicated no effect for all acid pH and for pH 9.0-9.5. Individual analysis indicated behavioral differences for most ...
Payeur Amy L - - 2012
A comprehensive two-dimensional gas chromatography (GC×GC) time-of-flight mass spectrometry method was developed for determination of fatty acids (irrespective of origin, i.e., both free fatty acids and fatty acids bound in sources such as triglycerides) in cultured mammalian cells. The method was applied to INS-1 cells, an insulin-secreting cell line commonly ...
Zhang Zhao-Cai - - 2012
PURPOSE: The purpose of the study was to evaluate the value of heart-type fatty acid-binding protein (hFABP) as a novel clinical biomarker in patients with severe sepsis. METHODS: Serum concentrations of hFABP and traditional cardiac biomarkers including cardiac troponin I, creatine kinase-MB, and B-type natriuretic peptides levels were measured within ...
Kim Jae Kwang - - 2012
Lipophilic compounds from Korean perilla ( Perilla frutescens ) seeds were characterized to determine the diversity among their phytochemicals and to analyze relationships between their contents. Twenty-four metabolites consisting of policosanol, phytosterol, tocopherol, and fatty acids were identified. The metabolite profiles were subjected to data mining processes, including principal component ...
Matsui Toru - - 2012
We report a scheme for estimating the acid dissociation constant (pK(a)) based on quantum-chemical calculations combined with a polarizable continuum model, where a parameter is determined for small reference molecules. We calculated the pK(a) values of variously sized molecules ranging from an amino acid to a protein consisting of 300 ...
Delmonte Pierluigi - - 2012
The SLB-IL111, a new ionic liquid capillary column for gas chromatography available from Supelco Inc., was recently shown to provide enhanced separation of unsaturated geometric and positional isomers of fatty acid (FAs) when it was compared to cyanopropylsiloxane (CPS) columns currently recommended for the analysis of fatty acid methyl esters ...
Jinnouchi Ryosuke - - 2012
A first principles theory combined with a continuum electrolyte theory is applied to adsorption of sulfuric acid anions on Pt(111) in 0.1 M H(2)SO(4) solution. The theoretical free energy diagram indicates that sulfuric acid anions adsorb as bisulfate in the potential range of 0.41 < U≤ 0.48 V (RHE) and ...
Woon Esther C Y - - 2012
2-Oxoglutarate dependent nucleic acid demethylases are of biological interest because of their roles in nucleic acid repair and modification. Although some of these enzymes are linked to physiology, their regulatory roles are unclear. Hence there is a desire to develop selective inhibitors for them; we report studies on AlkB which ...
Liu Guansai - - 2012
Densely functionalized cyclopentenones are useful synthetic intermediates. We report herein a new method to synthesize this important class of compounds through a highly enantioselective (98 → 99% ee) triene cyclization that is cocatalyzed by acetic acid and a chiral N-heterocyclic carbene (NHC). We discovered that acetic acid not only could coexist with ...
Izumikawa Miho - - 2012
The search for metabolites of Kibdelosporangium sp. AK-AA56 resulted in the discovery of novel N-phenylacetylated peptides, JBIR-78 (1) and JBIR-95 (2). Compounds 1 and 2 were established to be N-phenylacetylated heptapeptides by extensive NMR and HRESIMS analyses. The absolute configuration of the standard amino acids including a cysteic acid moiety ...
Lin Sheng - - 2012
Nine new fatty acid derivatives, including seven methoxylated (1, 2, and 4-8) and two hydroxylated (3 and 9) fatty acids, have been isolated from the ethanol extract of the stem bark of Fraxinus sieboldiana. Their structures were determined by spectroscopic methods including IR, MS, 1D, and 2D NMR experiments. The ...
Sanchez-Hernandez Laura - - 2012
A novel screening method using an automated flow-injection electrospray ionization tandem mass spectrometry system is proposed for the simultaneous determination of five non-protein amino acids (β-alanine, alloisoleucine, ornithine, citrulline, pyroglutamic acid) and three betaines (glycine betaine, trigonelline, proline betaine) after derivatization with butanolic HCl. MS/MS experiments were carried out in ...
Harmanescu Monica - - 2012
The aim of our work was to compare two methods, both based on direct transmethylation with different reagents, BF3/MeOH (boron trifluoride in methanol) or HCl/MeOH (hydrochloride acid in methanol), in acid catalysis, without prior extraction, to find the fast, non-expensive but enough precise method for 9 principal fatty acids (lauric, ...
Dettmer Katja - - 2012
Two mass spectrometry-based methods for the quantitative analysis of free amino acids are described. The first method uses propyl chloroformate/propanol derivatization and gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis in single-ion monitoring mode. Derivatization is carried out directly in aqueous samples, thereby allowing automation of the entire procedure, including addition of ...
Fisher George H - - 2012
D: -Amino acids are stereoisomers or optical isomers of naturally occurring L: -amino acids and thus possess the same chemical structure, but may differ in their biological/physiological properties. Until a half century ago, D: -amino acids had been considered to be unnatural substances found only in microorganisms. However, improvements in ...
de Andrade Mauricio Pacheco - - 2012
Abstract Background: The biorhythm of serum uric acid was evaluated in a large sample of a clinical laboratory database by spectral analysis and the influence of the gender and age on uric acid variability. Methods: Serum uric acid values were extracted from a large database of a clinical laboratory from ...
Giordano Giuseppe - - 2012
Enzyme deficiencies in amino acid (AA) metabolism affecting the levels of amino acids and their derivatives in physiological fluids may serve as diagnostically significant biomarkers for one or a group of metabolic disorders. Therefore, it is important to monitor a wide range of free amino acids simultaneously and to quantify ...
Gogichaeva Natalia V - - 2012
Here, we describe two different amino acid analysis protocols based on the application of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry (MS). First protocol describes a MALDI TOF MS-based method for a routine simultaneous qualitative and quantitative analysis of free amino acids and protein hydrolysates (Alterman et al. ...
Hannoush Rami N - - 2012
Methods to detect and characterize cellular protein myristoylation and palmitoylation are invaluable in cell biology, immunology, and virology. Recently, we developed ω-alkynyl fatty acid probes for monitoring myristoylation and palmitoylation of cellular proteins. This article describes a biochemical procedure for metabolic labeling of cells with ω-alkynyl fatty acids and click ...
Bunk David M - - 2012
The role of amino acid analysis in bioanalysis has changed from a qualitative to a quantitative technique. With the discovery of both electrospray ionization and matrix-assisted laser desorption ionization in the early 1990s, the use of amino acid analysis for qualitative analysis of proteins and peptides has been replaced by ...
Tripp Jennifer A - - 2012
Single-compound analysis of stable or radio-isotopes has found application in a number of fields ranging from archaeology to forensics. Often, the most difficult part of these analyses is the development of a method for isolating the compounds of interest.Here, we describe three complementary preparative HPLC procedures suitable for separating and ...
Palego Lionella - - 2012
The measurement of physiological amino acids in body fluids and circulating cells can be relevant in the search for biological correlates of neuropsychiatric, neurological, body weight, and pain diseases. Several techniques are available for the quantitative analysis of free amino acids, including UV detection after precolumn derivatization. These systems have ...
Hughes Alun - - 2012
Here, we present methods for extracting DNA and RNA from samples of whole bone tissue and culture bone cells and describe methods quantitative and qualitative measurement of the extracted nucleic acids. These protocols described provide high-quality nucleic acids suitable for downstream applications such as quantitative PCR and microarrays.
Hirayama Akiyoshi - - 2012
A method for the determination of underivatized amino acids based on capillary electrophoresis-mass spectrometry is described. To analyze free amino acids simultaneously, a low acidic pH electrolyte was used to confer positive charge on whole amino acids. All protonated amino acids migrated toward the cathode in CE and then were ...
Rombouts Ine - - 2012
This chapter describes an accurate and user-friendly method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions. The method consists of hydrolysis of the peptide bonds in 6.0 M hydrochloric acid solution at 110°C for 24 h, followed by evaporation of the acid and ...
Hess Sonja - - 2012
The determination of the stereochemistry of common and unusual amino acids is important in food chemistry, archeology, medicine, and life sciences, including such diverse areas as marine biology and extraterrestrial chemistry and has greatly contributed to our current knowledge in these fields.To determine the stereochemistry of amino acids, many chromatographic ...
Zunińá Gordana D - - 2012
Whole blood and/or plasma amino acids are useful for monitoring whole body protein and amino acid metabolism in an organism under various physiological and pathophysiological conditions. Various methodological procedures are in use for their measurement in biological fluids. From the time when capillary electrophoresis was introduced as a technology offering ...
Poinsot Véréna - - 2012
This paper describes the most important articles that have been published on amino acid analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138) and Poinsot et ...
Mirgorodskaya Olga A - - 2012
Amino acid analysis is among the most accurate methods for absolute quantification of proteins and peptides. Here, we combine acid hydrolysis with the addition of isotopically labeled standard amino acids and analysis by mass spectrometry for accurate and sensitive protein quantitation. Quantitation of less than 10 fmol of protein standards ...
Klem Sabrina - - 2012
Red blood cell (RBC) n-3 fatty acid status is related to various health outcomes. Accepted biological markers for the fatty acid status determination are RBC phospholipids, phosphatidylcholine, and phosphatidyletholamine. The analysis of these lipid fractions is demanding and time consuming and total phospholipid n-3 fatty acid levels might be affected ...
Goulas Vlasios - - 2011
INTRODUCTION: Triterpenic acids, such as maslinic acid and oleanolic acid, are commonly found in olive fruits and have been associated with many health benefits. The drying and extraction methods, as well as the solvents used, are critical factors in the determination of their concentration in plant tissues. Thus, there is ...
Chowdhury Taniya Roy - - 2011
Phospholipid fatty acid (PLFA) as biomarkers, is widely used to profile microbial communities in environmental samples. However, PLFA extraction and derivatization protocols are not standardized and have widely varied among published studies. Specifically investigators have used either HCl/MeOH or KOH/MeOH or both for the methylation step of PLFA analysis, without ...
Huang Tao T Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, - - 2012
Single amino acid polymorphisms (SAPs), also known as non-synonymous single nucleotide polymorphisms (nsSNPs), are responsible for most of human genetic diseases. Discriminate the deleterious SAPs from neutral ones can help identify the disease genes and understand the mechanism of diseases. In this work, a method of deleterious SAP prediction at ...
Anderson Kyle - - 2011
This paper reports the use of plasma enhanced chemical vapor deposition (PECVD) for the simultaneous deposition and co-polymerization of an amino acid with other organic and inorganic monomers. We investigate the fundamental effects of plasma-enhanced co-polymerization on different material chemistries in stable ultrathin coatings with mixed composition with aminoacid component. ...
Zhao Yanchuan - - 2011
Trifluoroethylation: Aryl boronic acids can be catalytically trifluoroethylated with the readily available reagent CF(3) CH(2) I (see scheme, dba=dibenzylideneacetone). The reaction tolerates a variety of functional groups and can be extended to the trifluoroethylation of aryl or alkenyl boronic esters. The method is also suitable for the late-stage installation of ...
Buurmans Inge L C - - 2011
A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components (zeolite, clay, alumina and silica) was monitored by UV/Vis micro-spectroscopy and showed ...
Mayali Xavier - - 2012
Most microorganisms remain uncultivated, and typically their ecological roles must be inferred from diversity and genomic studies. To directly measure functional roles of uncultivated microbes, we developed Chip-stable isotope probing (SIP), a high-sensitivity, high-throughput SIP method performed on a phylogenetic microarray (chip). This approach consists of microbial community incubations with ...
Shaw Paul B - - 2011
In alkaline pulping wood pulp is reacted with concentrated aqueous alkali at elevated temperatures. In addition to producing cellulose for the manufacture of paper, alkaline pulping also generates large amounts of isosaccharinic acids as waste products. Isosaccharinic acids are potentially useful raw materials: they are good metal chelating agents and, ...
Masuda A - - 2011
Amino acid analysis (AAA) method is the most accurate methodology for absolute quantification of proteins. The conventional postcolumn method employing ninhydrin labeling of amino acids, which is adopted in automatic amino acid analyzer, is limited by low sensitivity. Therefore, a highly sensitive AAA method is required to confirm the data ...
Viglio Simona - - 2011
This report intends to provide an updated overview of the most important methodological developments of MEKC in the field of qualitative/quantitative analysis of free amino acids in different matrices. A good number of articles published in the years 2009-2010 addresses the main applications of such procedures together with their advantages ...
Michelson Anna Zhachkina - - 2011
The fundamental properties of the parent and substituted 2-pyridones (2-pyridone, 3-chloro-2-pyridone, 3-formyl-2-pyridone) have been examined in the gas phase using computational and experimental mass spectrometry methods. Newly measured acidities and proton affinities are reported and used to ascertain tautomer preference. These particular substrates (as well as additional 3-substituted pyridones) were ...
Chen Hui - - 2011
We describe herein a novel exonuclease III aided amplification method based on single walled carbon nanotube quenching (EASQ) for sensitive and convenient nucleic acid detection, which enabled 80-fold decrease of detection limit for HIV1 DNA assay compared with no target recycling.
Wang Yang - - 2011
A rapid synchronous spectrofluorimetric method was first developed for the simultaneous determination of folic acid and riboflavin in nutrimental beverages. Folic acid could be detected by using H(2)O(2) plus Cu(II) as oxidation system to produce pterine-6-carboxylic acid, which had strong fluorescence in aqueous solution, and riboflavin itself was obviously fluorescent. ...
Simonsen Richard J - - 2011
The breakthrough discovery of the acid-etch procedure by Buonocore in the mid-1950s laid the groundwork for the development of pit and fissure sealant as the best preventive agent for use against the development and progression of pit and fissure caries. The acid-etch technique is also the foundational technology behind the ...
Porter William H - - 2012
Ethylene glycol poisoning is a medical emergency that presents challenges both for clinicians and clinical laboratories. Untreated, it may cause morbidly or death, but effective therapy is available, if administered timely. However, the diagnosis of ethylene glycol poisoning is not always straightforward. Thus, measurement of serum ethylene glycol, and ideally ...
García-Delgado C - - 2012
Six digestion procedures were tested to improve extraction methods for determination of trace elements in various organic amendments with high inorganic fractions. These procedures were tested in terms of pH, CaCO(3), organic matter, elemental analysis, BCR sequential extraction and X-ray diffraction analysis. Aqua regia extraction (ISO 11466), total digestion HF-HNO(3)-HClO(4) ...
Bartus Cynthia L - - 2011
A number of injection techniques have been described for the placement of hyaluronic acid fillers. Such techniques include, but are not limited to, linear threading, depot, fanning, and layering. The tower technique for hyaluronic acid filler injection is a novel variation of the depot and layering techniques. With this technique, ...
Demange Martine - - 2011
In France, the MétroPol 009 method used to measure workplace exposure to inorganic acids, such as HF, HCl, and HNO(3), consists of a closed-face cassette fitted with a prefilter to collect particles, and two sodium carbonate-impregnated filters to collect acid vapor. This method was compared with other European methods during ...
Kim E J - - 2011
The objective of this study was to evaluate and compare amino acid digestibility of several feedstuffs using 2 commonly accepted methods: the precision-fed cecectomized rooster assay (PFR) and the standardized ileal amino acid assay (SIAAD). Six corn, 6 corn distillers dried grains with or without solubles (DDGS/DDG), one wet distillers ...
Robert-Peillard F - - 2012
This paper presents a simple, accurate and multi-sample method for the determination of volatile fatty acids (VFAs) thanks to a 96-well microplate technique. A procedure using an activating reagent of the carboxylic function (water-soluble carbodiimide EDC) and a fluorescent amino labeling reagent (N-(1-naphthyl)ethylenediamine, EDAN) allows the formation of an isoindole ...
1 2 3 4 5 6 7 8 9 10 >