Ultrathin-layer sodium dodecyl sulfate disc electrophoresis of proteins in the range from 10 to 220 kDa in homogeneous,low-concentrated polyacrylamide gels

This study describes an ultrathin-layer sodium dodecyl sulfate (SDS) disc electrophoresis in polyacrylamide gels of a thickness of only 150 microm. By use of 2-amino-2-methyl-1,3-propanediol/glycine instead of traditional Tris/HCl buffer in the resolving phase of the gel, proteins with a wide range of molecular sizes (10 kDa to over 220 kDa) are separated in unusually low-concentrated gels (4%T, 3.3%C). 2-Amino-2-methyl-1,3-propanediol in the resolving part of the gel contributes to stabilization of the pH value at 8.8, while glycine improves destacking as well as separation of small proteins from the bulk of stacked SDS. This method combines both the advantages of conventional slab-gel electrophoresis and capillary gel electrophoresis. It is easy to apply and well suited for all further miniaturization attempts.     

Cleavage of the Fe—Fe Bond of （Me2SiSiMe2） [η^5－C5H4Fe（CO）2]2 with Na／Hg and Molecular Structure of the Ring－Opened Complex

The reaction of the rifle cyclic complex (1) with sodium amalgam in THF resulted in the expected cleavage of the Fe-Fe bond to afford his-sodium salt ( Me2SiSiMe2 ) [η^5-C5H4Fe(CO)2]2 (4). The latter was not isolated and was used directly to react with MeI, PhCH2Cl, CH3C(O)Cl, PhC(O)Cl,Cy3SnCl (Cy= cyclohexyl) or Ph3SnCl to afford corresponding ring-opened derivatives (Me2SiSiMe2) [η^5-C5H4Fe(CO)2]2 [5, R=Me; 6, R=PhCH2; 7, R=CH3C(O); 8, R=PhC(O); 9, R = Cy3Sn or 10, R = Ph3Sn ]. The crystal and molecular structures of 10 were determined by X-ray diffraction analysis. The molecule took the desired ant/ conformation around the Si-Si bond. The length of the Si--Si bond is 0.2343(3)nm, which is essentially identical to that in the cyclic structure of 1[0.2346(4) tun]. This result unambiguously demonstrates that the Si--Si bond in the cyclic structure of 1 is not subject to obvious strain.     

ESR study of photooxidation of phenothiazines in aqueous micellar solutions

The mechanism of photooxidation of phenothiazine in liquid and frozen (77 K) aqueous micellar solutions of the surfactant (sodium dodecyl sulfate) was studied by ESR. The main reaction of electrons formed by the photochemical oxidation of phenothiazine in a liquid micellar solution of the anionic surfactant is the reduction of molecular oxygen dissolved in the aqueous bulk phase. 10-Methylphenothiazine was used as a stable radical cation probe in a liquid solution. The influence of electrolytes on the photoionization yield in both frozen and liquid solutions of the surfactant was studied.     

Potassium and sodium 2,6-di-tert-butylphenoxides and their properties

The crucial factor of the reaction of 2,6-di-tert-butylphenol with alkali hydroxides is temperature, depending on which two types of potassium or sodium 2,6-di-tert-butylphenoxides are formed. These types exhibit different catalytic activity in the alkylation of 2,6-di-tert-butylphenol with methyl acrylate. More active forms of 2,6-Bu^t ₂C₆H₃OK or 2,6-Bu^t ₂C₆H₃ONa are synthesized at temperatures higher than 160 °C and are predominantly the monomers, which dimerize on cooling. The data of ¹H NMR, electronic, and IR spectra for the corresponding forms of 2,6-Bu^t ₂C₆H₃OK and 2,6-Bu^t ₂C₆H₃ONa isolated in the individual state are in agreement with cyclohexadienone structure. In DMSO or DMF, the dimeric forms of 2,6-di-tert-butylphenoxides react with methyl acrylate to form methyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate in 64–92% yield. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2138–2143, December, 2006.     

Preconcentration and Determination of Chromium Species Using Octadecyl Silica Membrane Disks and Flame Atomic Absorption Spectrometry

A novel and selective method for the fast determination of trace amounts of chromium species in water samples has been developed. The procedure is based on the selective formation of chromium diethyldithiocarbamate complexes at different pH in the presence of Mn(II) as an enhancement agent of chromium signals followed by elution with organic eluents and determination by atomic flame absorption spectrometry. The maximum capacity of the employed disks was found to be (396±3) µg and (376±2) µg for Cr(III) and Cr(VI), respectively. The detection limit of the proposed method is 49 and 43 ng·L^?1 for Cr(III) and Cr(VI), respectively. The proposed method was successfully applied for determination of chromium species Cr(III) and Cr(VI) in different water samples.     

Al3+离子对卵磷脂聚集体结构的影响

本文用浊度滴定(UV-Vis)、透射电镜(TEM)和激光光散射(QELS)等方法对Al³⁺离子与卵磷脂(EYPC)囊泡之间的相互作用及其这种相互作用对溶液中磷脂微结构的影响进行了研究。结果表明，一定量的Al³⁺离子使EYPC多层囊泡转变为线团状聚集体;Al³⁺与牛磺胆酸钠(TC)的协同作用可以破坏EYPC的多层囊泡结构，促进相转变，形成混合胶束。     

Spectrophotometric method for the determination of demeclocycline using sodium molybdate as analytical reagent

By means of spectroscopic methods it has been found that demeclocycline reacts with molybdate ions forming a complex compound [MoO₃HDMTC]^2–. The relative stability constant of this compound has been determined by applying spectrophotometric methods. Under optimum conditions for complex formation a very sensitive spectrophotometric method for the estimation of demeclocycline in the concentration range 5.0–35.1 g/ml is proposed. The detection limit of the method is 2.5 g/ml of demeclocycline. The relative standard deviation (n=10) varies between 0.76% and 1.46%. The method proved to be accurate and sensitive for the analysis of the demeclocycline content in tablets.     

Thermal decomposition of sodium nitrite and sodium nitrate pre-adsorbed on TiO2 surfaces

The thermal decomposition of sodium nitrite or nitrate pre-adsorbed upon TiO₂ surfaces has been investigated by employing several techniques as infrared spectroscopy (IR) and temperature programmed desorption in conjunction with mass spectrometry analysis (TPD-MS) to study the features observed during these thermal decompositions. Differential thermal analysis (DTA) in combination with X-ray diffraction analysis (XRD) were used to investigate the possibility of a solid state chemical reaction between the solid products originated from the thermal decomposition of the pre-adsorbed species and the TiO₂. On the basis of our results, various characteristic features of these thermal decomposition reactions will be discussed.This work was supported by JUNTA DE ANDALUCIA (financial support for research groups/1990).     

An expedient esterification of aromatic carboxylic acids using sodium bromate and sodium hydrogen sulfite

Treatment of aromatic carboxylic acids and substituted toluenes with a mixture of sodium bromate and sodium hydrogen sulfite in a two-phase system gave the corresponding esters in good yield. The intermediate α-brominated toluene was formed by the in situ generated hypobromous acid. The α-bromotoluene underwent an intermolecular nucleophilic substitution reaction with aromatic carboxylic acids present in the reaction mixture to afford the corresponding esters.     

Electron Transport Properties of Ions in Aqueous Solutions of Sodium Selenite

Ion diffusion kinetics has been studied using the data of conductivity measurements for aqueous solutions of sodium selenite with different concentrations and at different temperatures. Molecular and ionic self-diffusion coefficients have been determined for infinitely dilute solutions in the temperature range 288 K-313 K. The limiting values of ion mobility and changes in the energies of translation of water molecules from ions’ hydration shell have been found. At elevated temperatures, ΔE _tr ⁰ increases for both ions in direct proportion to the crystallographic radius of the latter. Ion hydration numbers at 298 K have been calculated. The results of this study are interpreted in the light of Samoilov’s theory on positive and negative hydration of ions.Original Russian Text Copyright © 2004 by L. T. Vlaev and S. D. Genieva__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 870–876, September–October, 2004.