Point interactions with inner structure as a limit of separable potentials

Interactions of zero radius with an additional inner channel are considered. The corresponding generalized Krein resolvents in a functional sector are approximated in the weak sense with the aid of interactions of rank 1. The cut-off procedure of the interaction is explicitly described in prepresentation.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova Akademii Nauk SSSR, Vol. 182, pp. 113–122, 1990.     

Magnetic fluorescence and phosphorescence quenching of gas-phase sulfur dioxide

Sulfur dioxide fluorescence and phosphorescence are quenched by a magnetic field. A model is suggested for the qualitative interpretation of the results.

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Laser-selective enrichment of 3d-states of the Ca II ion for detecting rare radioactive isotope calcium-41

For the detection of the rare radioactive isotope⁴¹Ca, the possibilities of the earlier-proposed initial-state enrichment by continuous-wave laser radiation are examined. It is shown that the enrichment 10¹⁴ of 3d-states of the ion Ca II can be reached. As the method of enriched-state detection, the process of resonant charge exchange is analysed. For a further increase of the selectivity, the repetition of the cycle initial state enrichment plus resonant charge exchange is discussed.     

Modification of sturgeon protamines with succinic anhydride

The modification of the - and -NH₂ groups of sturins A and B — protamines fromAcipenser güldenstadti — with succinic anhydride has been studied. Succinylation was carried out at 20°C, pH from 7.5 to 10.5, using a 50 to 180-fold excess of succinic anhydride. The modification products were separated by reversed-phase HPLC on a Zorbax ODS column. A linear relationship has been established between the retention times of the succinyl derivatives and the number of succinyl groups introduced. The influence of the pH and of the excess of succinic anhydride on the modification of the sturins has been studied by the method of experimental planning and mathematical modeling. The optimum conditions have been found for the succinylation of the proteins: a 150- to 180-fold excess of succinic anhydride and pH values of 9.8–10.2 for sturin A and of 8.4–9.4 for sturin B.Moscow Technological Institute of the Meat and Dairy Industry. All-Union Scientific-Research Institute for the Search for New Antibiotics, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 238–243, March–April, 1989.     

Cyclomagnesiation of nitrogen-containing 1,2-dienes with grignard compounds catalyzed by Cp<Subscript>2</Subscript>TiCl<Subscript>2</Subscript>

Cyclomagnesiation of nitrogen-containing 1,2-dienes with Grignard compounds in the presence of activated magnesium and Cp₂TiCl₂ as catalyst afforded 2,5-bis(aminoalkylidene)magnesacyclopentanes in high yield.     

Beam of monoenergetic neutrons for the calibration of a dark-matter detector

A new method has been proposed for obtaining a beam of monoenergetic neutrons with almost arbitrary energies. The production of the beam for the calibration of a dark-matter detector with liquid argon as a working medium has been described.     

Mechanistic studies on the reaction between glutathionylcobalamin and selenocysteine

Abstract

The reaction between glutathionylcobalamin (GSCbl), a complex of Co(III)-cobalamin with glutathione, and selenocysteine (Sec) was investigated using ultraviolet-visible (UV–vis) spectroscopy. The interaction results in the formation of cob(II)alamin and proceeds via two pathways: (i) a rapid formation of complex between GSCbl and Sec followed by the rate-determining substitution of glutathionyl-ligand by Sec and rapid electron-transfer from Se-atom to Co(III)-ion and (ii) a nucleophilic attack of Co(III)-S bond by Sec.