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941.
Maria G. Chernysheva Gennadii A. Badun 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(3):835-840
A new technique for in vitro studies of biomacromolecules interactions, their adsorption at aqueous/organic liquid interfaces
and distribution in the bulk of liquid/liquid systems was developed. The method includes (1) tritium labeling of biomolecules
by tritium thermal activation method and (2) scintillation phase step with organic phase, which can be concerned as a model
of cellular membrane. Two globular proteins lysozyme and human serum albumin tested. We have determined the conditions of
tritium labeling when labeled by-products can be easy separated by means of dialysis and size-exclusion chromatography. Scintillation
phase experiments were conducted for three types of organic liquids. Thus, the influences of the nature of organic phase on
proteins adsorption and its distribution in the bulk of aqueous/organic liquid system were determined. It was found that proteins
possess high surface activity at aqueous/organic liquid interface. Furthermore, values of hydrophobicity of globular proteins
were found by the experiment. 相似文献
942.
Maria J. Alves Vera C.M. Duarte Hélio Faustino António Gil Fortes 《Tetrahedron: Asymmetry》2010,21(15):1817-1820
Erythrose benzylidene-acetal 1,3-butadienes are studied as partners in Diels–Alder cycloadditions. A high diastereofacial improvement is found in cases where both the alcohol function is protected and a π–π interaction between the diene and dienophile is possible. Several competing factors have been studied independently in order to explain its influence on the selectivity of the cycloadditions. 相似文献
943.
Soraa Bouattour Wannes Kallel Ana Maria Botelho do Rego L.F. Vieira Ferreira I. Ferreira Machado Sami Boufi 《应用有机金属化学》2010,24(10):692-699
This work reports on the synthesis of Li‐doped TiO2 nanoparticles using the sol–gel process and solid‐state sintering, and investigates their potential use as a photocatalyst for degradation under sunlight excitation of different organic model compounds in aqueous solution. The structure of the nanocrystals was examined by X‐ray diffraction, UV‐vis ground state diffuse reflectance absorption spectra and X‐ray photoelectron emission spectroscopy. Results showed that samples prepared by sol–gel process and calcined at 400 °C are composed of a mixture of anatase and rutile phases, in contrast to the one prepared by solid‐state sintering, which exhibits an anatase phase with Li being involved in a spinel phase. The photocatalytic degradation of aqueous solutions of different aromatic compounds was successfully achieved under sunlight excitation in presence of Li‐doped TiO2 prepared via sol–gel process. It was shown that the calcination temperature and the preparation mode greatly affect the photocatalytic efficiency. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
944.
Dr. Shaodong Zhou Dr. Jilai Li Dr. Maria Schlangen Prof. Dr. Helmut Schwarz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(9):3073-3076
Carbon‐atom extrusion from the ipso‐position of a halobenzene ring (C6H5X; X=F, Cl, Br, I) and its coupling with a methylene ligand to produce acetylene is not confined to [LaCH2]+; also, the third‐row transition‐metal complexes [MCH2]+, M=Hf, Ta, W, Re, and Os, bring about this unusual transformation. However, substrates with substituents X=CN, NO2, OCH3, and CF3 are either not reactive at all or give rise to different products when reacted with [LaCH2]+. In the thermal gas‐phase processes of atomic Ln+ with C7H7Cl substrates, only those lanthanides with a promotion energy small enough to attain a 4fn5d16s1 configuration are reactive and form both [LnCl]+ and [LnC5H5Cl]+. Branching ratios and the reaction efficiencies of the various processes seem to correlate with molecular properties, like the bond‐dissociation energies of the C?X or M+?X bonds or the promotion energies of lanthanides. 相似文献
945.
946.
We prove a uniform bound for the density, p
t
(x), of the solution at time t(0, 1] of a 1-dimensional stochastic differential equation, under hypoellipticity conditions. A similar bound is obtained for an expression involving the distributional derivative (with respect to x) of p
t
(x). These results are applied to extend the Itô formula to the composition of a function (satisfying slight regularity conditions) with a hypoelliptic diffusion process in the spirit of the work of Föllmer et al.
(5) 相似文献
947.
This paper presents a method for the determination of phenylephrine hydrochloride in pharmaceuticals by spectrophotometric flow injection analysis exploiting the reaction with potassium ferricyanide and 4-aminoantipyrine, which leads to the formation of a condensation product with strong absorptivity at 500 nm. The linear dynamic range was between 0.95 and 9 mg/L, with a limit of detection of 0.2 mg/L and a sampling throughput of 120 samples per hour. The method was applied to eyewashes and nasal decongestant liquid medicines. 相似文献
948.
An electrothermal atomic absorption (ETAAS) method for the determination of traces of iron (0.1-1.0 microgram g-1) in Fe-doped indium phosphide (InP) has been developed. In order to overcome the indium matrix-effect and to achieve a useful detection limit, a preliminary solvent-extraction of Fe(III) with acetylacetone (HAA) is necessary. After sample dissolution with hydrochloric acid (1 + 1) the digest is evaporated to dryness, Fe(II) is oxidized to Fe(III) with nitric acid, the residue is dissolved in 0.01 mol L-1 HCl and the iron is extracted at pH 2.0 with 0.5 mol L-1 HAA in toluene. The organic phase is injected into the graphite furnace and the iron is directly evaluated by external organic standard calibration. The limit of detection (3SB) resulting from further in-situ preconcentration is 0.03 microgram g-1. When the method was applied to the analysis of real samples containing 0.2-0.7 microgram g-1 Fe, the RSD was in the range 8-21%. Results were compared with those independently obtained on the decomposed sample solution with inductively coupled atomic emission spectrometry (ICP-AES). The detection limit of the ICP-AES method, that needs matrix-matched standards, is 0.20 microgram g-1. 相似文献
949.
A multicomponent background electrolyte (BGE) was developed and its composition optimized using artificial neural networks (ANN). The optimal BGE composition was found to be 90 mM boric acid, 115 mM Tris, and 0.75 mM EDTA (pH 8.4). A separation voltage of 20 kV, 20 degrees C and detection at 210 nm were used. The method was applied to characterize several humic acids originating from various countries of the American continent: soil (Argentina), peat (Brazil), leonardite (Guatemala and Mexico) and coal (United States). Comparison with humic acids of International Humic Substances Society (IHSS) standard samples was also done. Well reproducible electropherograms showing a relatively high number of peaks were obtained. Characterization of the samples by elemental analysis and UV spectrophotometry was also done. In spite of the very different origins, the similarities between humic acids are high and by matrix assisted desorption/ionization-time of flight (MALDI-TOF)-mass spectrometry it was shown that most of the m/z patterns are the same in all humic acids. This means that humic acids of different origin have the same structural units or that they contain the same components. 相似文献
950.
Density functional theory calculations on [LnCp2APh] (Ln = La, Lu; Cp = eta 5-C5H5; A = O, S; Ph = C6H5) suggest that the linearity of the Ln-O-C vectors arises largely as a result of electrostatic repulsion between the alpha carbon and the trivalent metal centre. 相似文献