Quantitative conversion spectroscopy of the ultrasoft isomeric transition of uranium-235 and the electronic structure of uranium oxides

Combined measurements of conversion electron spectra and the decay constant (76.5 eV, (1/2)⁺→(7/2)⁻) of the E3-isomeric transition of the uranium-235 nucleus have been performed with collection of the isomer atoms on an indium surface. The conversion spectra are interpreted as corresponding to a mixture of two different oxides A and B of uranium, one of which (A) is similar to UO₂, and the other (B) consists of a uranium-oxygen cluster based on the linear uranyl group O-U-O. From a set of mixed experimental spectra conversion spectra have been found corresponding to the chemical states A and B of the isomer atoms, and the variation of the absolute intensities of the conversion lines has been quantitatively investigated for them by varying the chemical composition of the isomer atoms and the ratio between the intensities of various conversion lines of the B spectrum. Experimental ratios between the intensities of the conversion lines are compared with the expected ratios in accordance with the distribution of the 6p electron density in the uranyl group. It is concluded that the experimental data agree with the calculation and that abrupt violations of proportionality of the partial probabilities of conversion of the electron density near the nucleus are absent. In accordance with the hypothesis of proportionality of the partial probabilities of conversion, an experimental estimate is given of the degree of localization of the deep-lying uranium 6p _1/2 shell during formation of the chemical bond in the uranyl group: around 70% of the 6p _1/2 electron density remains in the quasi-atomic uranium shell and around 30% is transferred to hybrid molecular orbitals. Zh. éksp. Teor. Fiz. 112, 574–595 (August 1997)     

Singlet-triplet pseudo Jahn-Teller centers in copper oxides

One of the most interesting attributes of a hole CuO ₄ ⁵ center in doped cuprates is the complexity of the ground state as a result of electronic pseudodegeneracy. An extra hole injected into the initial CuO ₄ ⁶ cluster with a b _1g hole can occupy not only the very same hybrid Cu 3d-O 2p orbital state, producing a Zhang-Rice A _1g singlet, but also the pure oxygen e _u state, generating a singlet or triplet ^1,3 E _u term, with close energies. The pseudo Jahn-Teller effect induced by pseudodegeneracy of the singlet ¹ A _1g and ¹ E _u terms is analyzed in detail. Fiz. Tverd. Tela (St. Petersburg) 40, 1795–1804 (October 1998)     

Polyunsaturated fatty acids of the α-linolenic series from insulin production wastes

The following polyenic acids has been isolated from insulin production waste and have been determined quantitatively: eicosa-5Z,8Z,11Z,14Z-pentaenoic, docosa-7Z,10Z,13Z,16Z,19Z-pentaenoic, and docosa-4Z,7Z,10Z,13Z,16Z,19Z-hexaenoic acids. They were identified by PMR and¹³C NMR.All-Union Scientific-Research Institute of the Technology of Blood Substitutes and Hormone Preparations, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 205–212, March–April, 1987.     

Solubilization of prothionamide with micelles of an amphiphilic acrylic acid oligomer with thiohexyl terminal groups and preparation of postoperative cavity filling formulations

An amphiphilic oligomer was prepared by telomerization of acrylic acid in the presence of n-hexyl mercaptan. The structure, molecular weight, critical micelle concentration, and ζ-potential of the oligomer, and also its particle-size distribution in aqueous solution were determined. The product allows solubilization of prothiondamide antituberculosis drug. A procedure was suggested for preparing a filling formulation containing prothionamide for filling postoperative cavities in connective tissue.     

Renormalized entropy solutions to the Cauchy problem for first order quasilinear conservation laws in the class of periodic functions

We introduce the notion of a periodic in spatial variables renormalized entropy solution to the Cauchy problem for a first order quasilinear conservation law. We prove the existence and uniqueness theorems and comparison principle. We also clarify relations with generalized entropy solutions. Bibliography: 19 titles. Illustrations: 1 figure.     

Structure of a pectin homogalacturonan

A homogalacturonan has been isolated in the pure form from industrial apple pectin, and its structure has been studied by¹³C NMR spectroscopy. It has been shown that the apple pectin macromolecule consists mainly of linear macromolecules of homogalacturonan and a rhamnogalacturonan.V. I. Nikitin Institute of Chemistry, Tadzhikistan Republic Academy of Sciences, Dushanbe; and Scientific Research Institute of Blood Substitutes and Hormone Preparations, Moscow. Translated from Khimiya Prirodnykh Soedeninii, No. 1, pp. 91–96, January–February, 1993.