Synthesis of new chiral mono-, di-, tri-, and tetraalkylglycolurils

Two general procedures were developed for the synthesis of chiral N-mono-, N, N′-di-, N, N′ N″-tri-, and N, N′, N″, N′″-tetraalkylglycolurils based on the reactions of 4,5-dihydroxy-imidazolidin-2-ones or glyoxal with one or two moles of alkylureas, respectively, by acid catalysis. The reactions of N-monoalkyl- and N, N′-dialkylureas with glyoxal proceed regioselectively. The mechanism of these reactions was suggested and partly confirmed by quantum-chemical calculations and experimental data. The enantiomeric separation of some chiral glycolurils by chiral-phase HPLC was carried out for the first time.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 680–692, March, 2005.     

Inter‐elemental correlations in liver and lung tissue of rats with alimentary adiposity (SRXRF)

The distribution of adiposity steadily grows all over the world. The reasons of the adiposity increase, especially in the developed countries, are not well understood. In particular, the role of lungs in the development of adiposity is not clear. There are many enzymes in the lungs (as well as in the liver), providing the metabolic processes on a high level. Additionally, lung is the first organ which lipids are delivered to with blood after the food intake. The data on the inter‐elemental correlations in the lungs (concerning the alimentary adiposity) are not found in the literature. Thus, the investigation of trace element status of lungs and liver after the fatty food intake is expedient. The experiments were carried out on the adult nonlinear Wistar rats. Two series of the experiments were conducted with control (normal weigh) and animals with adiposity. Each of these series was subdivided into two groups: animals not having food (before the sacrifice) and receiving lard. The results obtained show that the metabolic changes under the alimentary adiposity of experimental rats are accompanied by the redistribution of inter‐elemental correlations in the liver and in the lungs either. The greatest number of strong correlations is observed in case of starving animals of control group. Copyright © 2012 John Wiley & Sons, Ltd.     

13C NMR study of the dissociation of tartaric and citric acids

The dissociation of tartaric and citric acid was studied by the ¹³C NMR method. All four dissociation constants of tartrate and citrate were determined directly from the pH-dependent shift of signals of carbon atoms making the composition of the hydroxy acids. It was shown that on successive splitting off of protons in tartaric acid, rings are formed between the carboxy and hydroxy groups, while in citric acid such rings are not formed.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 6, pp. 706–710, November–December, 1990.     

Complex formation in the system Fe(III)-ethylenediamine disuccinic acid

Spectrophotometry and nuclear relaxation was used to study the complex formation of Fe(III) with ethylenediaminedisuccinic acid in a broad interval of pH at different ratios of the components. A significant amount of complexes was formed in the acidic region; their stability constants have been determined. Mathematical treatment of the data has allowed calculation of the distribution diagrams of the complexes in the system as function of pH.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 26, No. 2, pp. 196–201, March–April, 1990.     

Determination of elemental composition of Lake Baikal sponges by wavelength dispersive X‐ray fluorescence spectrometry

Sponge endemic species inhabit the Lake Baikal from the ancient times. Because the sponges are the biological filters of the Baikal water and they contribute greatly to silicon circulation in the lake, it is crucial to analyze their composition. Only a few publications report the analytical data concerning the element composition of Lake Baikal sponges. However, the analytical data were mainly obtained by destructive methods. No data on the concentrations of some alkaline and volatile elements are available so far. This article describes the application of wavelength dispersive X‐ray fluorescence spectrometry to study the sponges of Lubomirskia baicalensis, Baikalospongia bacillifera, and Baikalospongia recta species collected at the littoral part of the Beryozovy Cape in the Southern Baikal. The concentrations of 19 elements Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, and Ba have been determined. In this article, we discuss the problem of selecting calibration samples for wavelength dispersive X‐ray fluorescence spectrometry, because appropriate reference samples are not available. The synthetic specimens, prepared by mixing plant certified reference materials and silicon dioxide in certain proportions, were proposed for calibration. The compositions of sponges cleaned from mineral particles and symbiotic organisms, as well as unwashed sponges, have been compared. Copyright © 2013 John Wiley & Sons, Ltd.     

Higher order symmetrizer and application to an unusual transport equation

We study a class of stationary transport equation with nonlocal low-order tems We obtain the existence and uniqueness of a solution in sobolev spaces     

求解复杂湍流的非线性涡黏性系数模型和代数应力模型

非线性涡黏性系数模型和代数应力模型联系了线性涡黏性系数湍流模型和完整的微分 雷诺应力模型.随着它们受到日益关注,其形式也越来越多样化.本篇综述的目的是对这些模 型加以总结并比较它们之间的共同点及不同之处,指出它们与完整微分雷诺应力模型之间的 关系,以及相对于线性涡黏性系数模型而言它们在预报流场上所具有的优势.     

Mercury in archeological hair samples from Xiongnu burials (Noin‐Ula,Mongolia): SR XRF and CXRM analysis

A technique has been developed for determining mercury content in the concentration range of 1–1000 μg/g in hair samples by X‐ray fluorescence analysis using synchrotron radiation (synchrotron radiation X‐ray fluorescence, Siberian Synchrotron and Terahertz Radiation Center, Budker Institute of Nuclear Physics SB RAS). The mercury content was identified in archeological hair samples from an ancient burial of Xiongnu nobility (Mongolia, mound 22, 1^st century BC–1^st century AD); the content values were elevated (up to 1100 μg/g) in all the samples (n = 41). An X‐ray microanalysis using polycapillary lenses in a confocal scheme (confocal X‐ray microscopy station) was developed at the Synchrotron radiation X‐ray fluorescence to establish mercury distribution in a cross section of hair shaft with a spatial resolution of 5 μm. The findings of the study make it possible to assume exogenous income of mercury (from the burial environment) to the hair.