Viktor Grigor’evich Berezkin is seventy-five

Chronicle

Viktor Grigor’evich Berezkin is seventy-five     

Oil in Louisiana's estuarine environments: A development model

Coastal erosion, accelerated by sea level rise, and subsidence are major Louisiana issues. With current sea-level-rise projections, coupled with the state's eroding barrier islands and coastal wetlands, the region's estuarine environments are in jeopardy of being lost, redefined, or permanently altered. As the coast erodes, Louisiana is endangered of losing valuable wetland's habitat. In addition, if the barrier islands disappear, the region's wetland-oriented oil and gas wells and associated infrastructure will be at risk to open Gulf conditions. If this should occur, each well, pipeline, and storage battery represents a potential environmental catastrophe.     

Determination of amino acids in human blood serum by reversed-phase high-performance liquid chromatography in the isocratic elution mode

A procedure is developed for the determination of 15 amino acids in human blood serum usingortho-phthalic aldehyde in combination with 2-mercaptoethanol or sodium sulfite as the reagent for the precolumn synthesis of derivatives with their subsequent separation by reversed-phase high-performance liquid chromatography in the isocratic elution mode using electrochemical detection. Conditions of the quantitative conversion of amino acids to corresponding derivatives were determined;ortho-phthalic—mercaptoethanol andortho-phthalic/sulfite derivatives of amino acids are stable during the whole cycle of analysis. The total time of separation is 80 min. The detection limits are 0.5-5 pmol (at the signal-to-noise ratio equal to 2). The procedure is used for the determination of glutamic acid, asparagine, serine, glutamine, histidine, taurine, alanine, arginine, methionine, isoleucine, ornithine, leucine, phenylalanine, lysine, and tryptophane in blood serum of healthy donors and of sick with alcoholism before and after treatment     

Controlled Fabrication of Cd-Bi Nanoparticles via Sonochemical Method

IntroductionMetal or alloy nanoparticles,because of their con-spicuous physicochemical properties,have been widelyapplied to various fields such as electronics,catalysis,magnetism,and corrosion-resistant materialsfields[1—4].It has been estimated that the particle sizeand the properties of nanoparticles depend strongly onthe specific method of fabrication and the applied ex-periment conditions,which makes the controlled syn-thesis of nanomaterials become an increasingly activeand important ar…     

素理想完全分裂的一个判别法则

本文给出了数域K内一个素理想在K的有限次正规扩域L内完全分裂的一个判别法则。     

Effect of Light on the Electrokinetic Behavior of TiO(2) Particles in Contact with Cr(VI) Aqueous Solutions

The electrokinetic behavior of titanium dioxide particles (Degussa P25, mainly composed of anatase) put in contact with chromium(VI) aqueous solutions is highly sensitive to light exposure under normal laboratory conditions. In the dark, adsorption of Cr(VI) gives rise to substantial decrements in the mobilities, especially in the acidic branch, and, at higher concentrations, to shifts in the isoelectric point (pH(piep)) to lower values, as expected for anionic chemisorption. A two-mode adsorption model accounts qualitatively for the results. Under light, pH(piep) shifts in the opposite direction as the Cr(VI) concentration increases. A maximum value is attained at [Cr(VI)] approximately 10(-3) mol dm(-3), pH(piep) 8.2, which coincides with values reported for hydrous chromium(III) oxides. At higher concentrations, Cr(VI) adsorption defines a shift of pH(piep) to lower values. It is concluded that light absorption by titanium dioxide promotes the reduction of Cr(VI) and the surface precipitation of the hydrous Cr(III) oxide. The values of pH(piep) for partially covered surfaces are well described by a simple model of surface ionization derived earlier. FTIR/ATR analysis of the surfaces supports this interpretation, and further suggests that one of the modes of Cr(VI) adsorption implies surface dimerization to yield adsorbed dichromate. Copyright 2000 Academic Press.     

A Robust, Environmentally Benign Catalyst for Highly Selective Hydroformylation

By a sol-gel process a rhodium complex containing a diphosphane with a large natural P-Rh-P bite angle is covalently anchored in a silica matrix (see picture). The immobilized catalyst is a very selective hydroformylation catalyst that is completely and conveniently separated from the product and can be reused in numerous cycles.     

Determination of steroids in biological samples by micellar electrokinetic chromatography

The possibility of determining eight adrenocorticotropic steroid hormones (cortisol, cortisone, corticosterone, 11-dehydrocorticosterone, 17-hydroxyprogesterone, 11-deoxycortisol, and progesterone) by micellar electrokinetic chromatography (MEKC) using urea as an organic additive to the working electrolyte (a 25 mM phosphoric acid solution and 10 mM sodium dodecyl sulfate) was demonstrated. The use of online preconcentration (stacking and sweeping) allowed us to lower the detection limit for steroids to ～3 ng/mL. The total analysis time was 15 min.