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61.
Rocío García-Villalba Alegría Carrasco-Pancorbo Ekaterina Nevedomskaya Oleg A. Mayboroda André M. Deelder Antonio Segura-Carretero Alberto Fernández-Gutiérrez 《Analytical and bioanalytical chemistry》2010,398(1):463-475
Olive oil polyphenols have important biological properties which closely depend on their bioavailability; it is, therefore,
essential to understand how polyphenols are absorbed, metabolized, and eliminated from the body. An analytical method based
on rapid-resolution liquid chromatography (RRLC) coupled with mass spectrometric detection with a time-of-flight analyzer
(RRLC–ESI-TOF MS) has been developed for analysis of the main olive oil phenolic compounds and their metabolites in human
urine. Urine samples from ten healthy volunteers were collected before and 2, 4, and 6 h after intake of 50 mL extra-virgin
olive oil. The proposed method includes liquid–liquid extraction with ethyl acetate, which provides extraction recoveries
of the phenolic compounds studied between 35 and 75% from spiked urine samples. Good repeatability was obtained—the relative
standard deviations (RSDs) of peak areas in intra-day and inter-day studies were 4.3 and 6.5%, respectively. Statistical studies
enabled us to discriminate between urine samples before and after intake, and facilitated the search for m/z values enabling this discrimination. Based on the very accurate mass information and the isotopic pattern provided by the
TOF MS analyzer, together with other available information, ten of these biomarkers and more than 50 metabolites, obtained
through phase I and phase II biotransformation reactions, were tentatively identified. Additionally, kinetic studies were
conducted on the metabolites identified as possible biomarkers; for most of the compounds concentrations were maximum in the
first two hours. 相似文献
62.
Levina EV Kalinovsky AI Dmitrenok PS Martyyas EA Stonik VA 《Natural product communications》2010,5(11):1737-1742
New steroid glycosides, hylodoside A (1) and novaeguinoside Y (2), along with previously known polyhydroxylated steroids (3-7) were isolated from the ethanolic extracts of the starfish Leptasterias hylodes reticulata and Culcita novaeguineae (juvenile). The structures have been elucidated using 1D and 2D NMR spectra (1H, 13C, DEPT, COSY-45, 1D-TOCSY, HSQCGP, ROESY, HSQC and HMBCGP) and mass spectrometry. Compound 3 was shown to inhibit the growth of Staphylococcus aureus up to 10% from the control at a concentration of 1 mg/mL. Steroids 1, 2 and 5 showed moderate hemolytic activity in the mouse erythrocytes assay. Compounds 3, 4 and 6 displayed pH-depended hemolytic properties. 相似文献
63.
Ekaterina P. Nesterenko Pavel N. Nesterenko Damian Connolly Flavie Lacroix Brett Paull 《Journal of chromatography. A》2010,1217(14):2138-2146
A new method for the fixation of polymethacrylate monoliths within titanium tubing of up to 0.8 mm I.D. for use as a chromatographic column under elevated temperatures and pressures is described. The preparation of butyl methacrylate–ethylene dimethacrylate-based monolithic stationary phases with desired porous structures was achieved within titanium tubing with pre-oxidised internal walls. The oxidised titanium surface was subsequently silanised with 3-trimethoxysilylpropyl methacrylate resulting in tight bonding of butyl methacrylate porous monolith to the internal walls, providing stationary phase stability at column temperatures up to 110 °C and at operating column pressure drops of >28 MPa. The titanium housed monoliths exhibited a uniform and dense porous structure, which provided peak efficiencies of up to 59,000 theoretical plates per meter when evaluated for the separation of small molecules in reversed-phase mode, under optimal conditions (achieved at 15 μL/min and temperature of 110 °C for naphthalene with a retention factor, k = 0.58). The developed column was applied to the reversed-phase isocratic separation of a text mixture of pesticides. 相似文献
64.
Vladimir Anashin Andrei Khrennikov Ekaterina Yurova 《Designs, Codes and Cryptography》2014,71(3):383-407
The paper presents new criteria for bijectivity/transitivity of T-functions and a fast knapsack-like algorithm of evaluation of a T-function. Our approach is based on non-Archimedean ergodic theory: Both the criteria and algorithm use van der Put series to represent 1-Lipschitz p-adic functions and to study measure-preservation/ergodicity of these. 相似文献
65.
Yury Yu. Rusakov Leonid B. Krivdin Stephan P. A. Sauer Ekaterina P. Levanova Galina G. Levkovskaya 《Magnetic resonance in chemistry : MRC》2010,48(1):44-52
Experimental measurements and second‐order polarization propagator approach (SOPPA) calculations of 77Se? 1H spin–spin coupling constants together with theoretical energy‐based conformational analysis in the series of 2‐substituted selenophenes have been carried out. A new basis set optimized for the calculation of 77Se? 1H spin–spin coupling constants has been introduced by extending the aug‐cc‐pVTZ‐J basis for selenium. Most of the spin–spin coupling constants under study, especially vicinal 77Se? 1H couplings, demonstrated a remarkable stereochemical behavior with respect to the internal rotation of the substituent in the 2‐position of the selenophene ring, which is of major importance in the stereochemical studies of the related organoselenium compounds. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
66.
V. E. Proskurina E. S. Shabrova A. P. Rakhmatullina Yu. G. Galyametdinov 《Russian Journal of Applied Chemistry》2017,90(10):1693-1699
Modified polysaccharide was synthesized by the reaction of amylopectin with a cationic monomer, (1,2-epoxyprop-3-yl)triethylammonium chloride, in alkaline solution in the presence of Fenton’s reagent. The influence of the concentrations of amylopectin, gelatin, their polymer-inorganic hybrids, and modified pectin on their flocculating properties in free (unrestricted) sedimentation of ocher suspension as a model disperse system was studied. Amylopectin exerts a stabilizing effect, whereas the modified pectin and polymer-inorganic hybrid exert a flocculating effect. The influence of the mode of introducing polymer additives on the flocculating effect and aggregation of ocher particles was analyzed. 相似文献
67.
68.
Andrey B. Koldobskii Nikolay P. Tsvetkov Ekaterina V. Solodova Valery N. Kalinin 《Journal of fluorine chemistry》2010,131(8):852-9595
This paper describes a novel synthetic approach to 2-cyano-3-trifluoromethylthiophenes fused with cyclobutene rings with variable spiro conjunctions. The reaction of substituted 1-bromo-2-trifluoroacetylcyclobutenes with mercaptoacetonitrile results in the substitution of bromine with S-center to afford the corresponding nitriles in high yields, which form the target thiophenes by subsequent treatment of lithium 2,2,6,6-tetramethylpiperidide and acetic anhydride. 相似文献
69.
70.
Ekaterina E. Stoikova Michail I. Sorvin Dmitry N. Shurpik Herman C. Budnikov Ivan I. Stoikov Gennady A. Evtugyn 《Electroanalysis》2015,27(2):440-449
A novel potentiometric sensor based on screen‐printed carbon electrode covered with electropolymerized polyaniline (PANI) and unsubstituted pillar[5]arene as ionophore has been developed and tested in potentiometric measurements of pH and metal ions. The introduction of pillar[5]arene improved the reversibility of the pH response in the range from 2.0 to 9.0 with the slope of 45 mV/pH. Among metal cations, the response to Fe3+ and Ag+ ions was referred to PANI redox conversion whereas the signal toward Cu2+ in the range from 1.0×10?6 to 1.0×10?2 M (limit of detection (LOD) 3.0×10?7 M) to specific interaction with the macrocycle. 相似文献