Formation of a metallic layer from individual atoms

Adsorption of copper, gold and beryllium on (110), (100), and (211) single-crystal planes of tungsten leads to essentially different work-function changes. It is known from numerous investigations of alkali-metal adsorption on metal substrates that the work-function variation reflects the electronic processes occurring during the formation of the adlayer. It is obvious that copper, gold and beryllium adsorption is accompanied by a wide variety of physical processes different from those appearing in alkali-metal adsorption. The existing experimental data concerning work-function changes induced by copper, gold and beryllium adsorption are compiled. A model is developed, which may explain these changes.     

Synthesis and biological activity of <Emphasis Type="Italic">N</Emphasis>-(2-hydroxyethyl)cytisine derivatives

Derivatives of N-(2-hydroxyethyl)cytisine, N-(2-hydroxypropyl)-, N-(2-hydroxy-2-(1-adamantyl)ethyl)-, and N-(2-hydroxy-2-phenylethyl)cytisine, were synthesized by reduction of N-(2-oxopropyl)-, N-(2-oxo-2-(1-adamantyl)ethyl)-and N-(2-oxo-2-phenylethyl)cytisine with metal hydrides. The antiarrhythmic and analgesic activities of the prepared compounds were investigated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 157–162, March–April, 2007.     

Swelling behavior of amphiphilic hydrogels of copolymers of the vinyl ether of ethylene glycol and vinyl isobutyl ether,and their interaction with cationic surfactant

Amphiphilic hydrogels of copolymers of the vinyl ether of ethylene glycol and vinyl isobutyl ether were synthesized by -radiation-induced free radical polymerization. Hydrogels with certain copolymer compositions showed thermo-sensitive behavior in aqueous solutions. The swelling behavior of the hydrogels in cetylpyridinium bromide aqueous solution was studied. Increased swelling of the hydrogels was observed in the surfactant solutions. The increased swelling was more prominent for the hydrogels with a higher content of hydrophobic moiety in the copolymer composition, and with higher surfactant concentration. The reason for this phenomenon is discussed. Treatment of some hydrogels in the surfactant solutions resulted in higher swelling ability in distilled water with distinct thermo-induced contraction over a narrow temperature interval.     

Strong intramolecular hydrogen bond N—H...O in 2-(2-acyl-1-phenylethenyl)-5-phenylpyrroles

The molecular structure of 2-(2-benzoyl-1-phenylethenyl)-5-phenylpyrrole and 2-(2-furoyl-1-phenylethenyl)-5-phenylpyrrole was studied by X-ray diffraction analysis at 110 K and quantum chemistry methods (B3LYP/6-31G*). In the crystalline state, both compounds have cyclic structures closed by strong intramolecular hydrogen bond N—H...O. Canonic zwitterionic structure contributes largely to the ground state of the molecules. This is probably due to synergism of the H-bonding and -electron interactions.     

Czechoslovakian biological certified reference materials and their use in the analytical quality assurance system in a trace element laboratory

Summary The Trace Element Laboratory of the University of Agriculture in Prague (CSFR) participated successfully in interlaboratory experiments on the determination of the contents of trace elements in seven Czechoslovakian reference materials. Czechoslovakian certified reference material CRM 12-02-01 (Bovine liver) was used for the development of a new analytical method using the Dry Mineralizer Apion as well as in analytical quality assessment of data in the determination of Cd, Pb, and Hg contents in routinely analyzed animal tissues.     

Steroids,LIII: New routes to aminosteroids

Summary Steroid ketoximes were reduced with sodium tetrahydroborate in the presence of nickel chloride or molybdenum trioxide. These processes yielded 17- and 20-aminosteroids (1c–5c) in higher yields than common reduction methods.

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Steroide, 53. Mitt.: Neue Wege zu Aminosteroiden

Zusammenfassung Oxime von Ketosteroiden wurden mit NaBH₄ in Gegenwart von NiCl₂ und MoO₃ reduziert. Dieses Verfahren lieferte 17- und 20-Aminosteroide(1c–5c) in größeren Ausbeuten als übliche Methoden.

     

Reaction of aminoquinolines with unsaturated carboxylic acids. 2. Cyclization of N-quinolyl-β-alanines

The cyclization of N-(3-quinolyl)- and N-(6-quinolyl)--alanines was carried out to give uncondensed hexahydropyrimidine derivatives, while the cyclization of N-(5-quinolyl)- and N-(8-quinolyl)--alanines gave tetrahydrophenanthrolinone derivatives.Communication 1, see ref. [1].Kaunas Technological University, 3028 Kaunas, Lithuania, Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 653–657, May, 2000.     

混合模式硅胶基质毛细管电色谱整体柱的制备及其电色谱性能研究

采用温和条件下的溶胶-凝胶技术，成功制备了阴离子交换-反相混合模式硅胶基质毛细管电色谱整体柱。通过调整反应液中不同前体的比例，优化了整体柱的制备条件。通过扫瞄电镜，对柱床进行了表征和分析。实验发现，所制备的整体柱电渗流的方向和大小可随流动相pH值的改变而改变，在酸性和中性条件下，具有从阴极流向阳极的电渗流；当流动相pH值升至约7．5时，电渗流方向发生了反转（由阳极流向阴极）。在优化的实验条件下，用所制备的整体柱对所考察的酸性（中性）化合物实现了快速分离，并获得了高达160，000N／m的柱效。     

Manipulation of protein fingerprints during on-column fluorescent labeling: protein fingerprinting of six Staphylococcus species by capillary electrophoresis

Bacterial proteomes were analyzed by use of electrophoretically mediated microanalysis (EMMA) and field-enhanced stacking. A water-soluble protein fraction was injected onto a capillary. Next, a fluorogenic reagent was injected and allowed to react with the protein mixture, producing fluorescent products that were separated by submicellar capillary electrophoresis and detected by laser-induced fluorescence. By use of a low-ionic strength sample buffer and a brief electrophoretic step, slow moving anionic proteins were stacked at the reagent-sample interface and were preferentially labeled. By reversing the order of sample injection and labeling reagent, fast moving cationic proteins were preferentially labeled. By adjustment of the sample buffer pH, proteins with different isoelectric points were selectively labeled. Electrophoresis fingerprints were generated for the water-soluble protein fraction from six Staphylococcus species. The protein patterns produced were species-specific and were used to construct a phylogenetic tree.