Calculation of the Characteristics of an Infinite Linear Queue for a Doubly Stochastic Incoming Stream

In the present paper, the mathematical expectation and variance of the number of queries in an infinite linear queue are calculated for the Poisson synchronous doubly stochastic stream of incoming queries with two intensity states.     

Operator algebras and lattices of invariant subspaces. II

For a bounded linear operator T the following questions are considered: the commutativity of the commutant {T}, the possibility of approximation in the weak operator topology of the operators from the bicommutant {T} , reflexivity, the equality of other operator algebras and lattices of subspaces connected with the operator T. Answers to this questions are given for operators from certain classes (C₀-contractions, weak contractions, contractions with finite defect indices, etc.).Translated from Zapiski Nauchnykh Seminarov I eningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 190, pp. 110–147, 1991.     

Mediated Bioelectrocatalytic Oxidation of Glucose on a Glucose Oxidase-Containing Composite

A composite material, which includes glucose oxidase (GOD), finely divided colloidal graphite, ferrocene, and Nafion, is developed and investigated. Kinetic parameters of redox conversions of GOD and flavin adenine dinucleotide, which is present in the active center of GOD, indicate that GOD in the composite retains molecular integrity and enzymic activity. Ferrocene in the composite undergoes reversible oxidation and is reduced on the electrode. Bioelectrocatalytic oxidation of glucose on the composite occurs via a mediator path, and the half-wave potential of a polarization curve recorded on the electrode in the presence of glucose coincides with the redox potential of ferrocene, which is equal to 0.32 V (Ag/AgCl). Effect of the ferrocene amount in the composite and the glucose concentration in the bulk solution on the glucose oxidation is studied. The results are used to optimize the composite's composition to ensure a stable operation of the enzyme electrode and effective glucose oxidation.     

Oxidative polymerization of aniline on the surface of insoluble solid poly(sulfo acids) as a method for the preparation of efficient biosorbents

Polyaniline coatings of the cation-exchange resin Dowex and a synthetic composite material based on silica gel surface-modified by a sulfated styrene-divinylbenzene copolymer were prepared by precipitative polymerization of aniline on the surface of the supports. The optimal conditions for the preparation of the polyaniline-containing material providing the formation of a thin polymeric coating on the support surface were determined. Aniline is predominantly consumed to the formation of a uniform polymeric coating about 3 nm thick with an increase in the concentration of sulfo groups on the support surface. The efficiency of using the polyaniline-containing sorbents for the preparative isolation of DNA from plant tissue lysates was demonstrated. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1123–1130, June, 2007.     

Phosphorus-based SAHA analogues as histone deacetylase inhibitors

[structure: see text] Three analogues of suberoyl anilide hydroxamic acid (SAHA) with phosphorus metal-chelating functionalities were synthesized as inhibitors of histone deacetylases (HDACs). The compounds showed weak activity for HeLa nuclear extracts (IC(50) = 0.57-6.1 mM), HDAC8 (IC(50) = 0.28-0.41 mM), and histone-deacetylase-like protein (HDLP, IC(50) = 0.33-1.9 mM), suggesting that the transition state of HDAC is not analogous to zinc proteases. Antiproliferative activity against A2780 cancer cells (IC(50) = 0.11-0.12 mM), comparable to SAHA (0.15 mM), was observed.     

An <Emphasis Type="Italic">ab initio</Emphasis> quantum-chemical study of the compounds HC≡CXCH<Subscript>3</Subscript> (X = O,S, Se)

The compounds HCCXMe (X = O, S, Se) were studied by the MP2(full)/6-31G* ab initio method using the method of natural bond orbitals. The parameters of the molecular geometry were obtained. The electron density distribution in these compounds is determined to a greater extent by the electronegativity of atoms X, than by conjugation of the lone electron pairs of the heteroatoms with the triple bond.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1823–1827.Original Russian Text Copyright © 2004 by Bzhezovskii, Kapustin, Chura, Shermolovich.This revised version was published online in April 2005 with a corrected cover date.     

Steric and Electronic Structure of Selenoanisole: A Quantum-Chemical Study

The potential functions of internal rotation around the C_sp2-Se bond in selenoanisole were ob- tained by quantum-chemical calculations in the approximations HF/3-21G(d), HF/6-31G(d), MP2(f)/6-31G(d), and B3LYP/6-31G(d). The calculations were performed in the range of variation of the torsion angle (between the planes of the benzene ring and C_sp2-Se-C_sp3 bonds) from 0° to 90° with 15° step. The energy minimum is in the region of the orthogonal conformation ( 90°), and the energy maximum, in the region of the planar form ( 0°). The rotation barriers (kJ mol^{- 1}) are as follows: HF/3-21G(d), 9.20; HF/6-31G(d), 13.13; MP2(f)/6-31G(d), 10.25; and B3LYP/6-31G(d), 6.41. The geometric parameters, Koopmans ionization potentials, and dipole moments are given. The energies, degrees of hybridization, populations of the lone electron pairs of Se, energies of their interaction with the antibonding * orbitals of the benzene ring, and electron density distributions were determined in terms of the natural bond orbital approach.     

Intramolecular Interactions in Anisole,Thioanisole, and Selenoanisole. Application of Natural Bond Orbitals Method

Calculations of molecules PhXMe (X = O, S, Se) in MP2(f)/6-31G(d) approximation were performed. The stationary points on the potential energy surface were determined and identified. The anisole molecule is planar with a barrier to rotation H 7.78 kJ mol^-1. In thioanisole and selenoanisole (H 3.08 and 10.25 kJ mol^-1 respectively) the energy minimum corresponds to an orthogonal form. Analysis of relation between intramolecular interactions and conformational structure of the molecules in question was performed by the method of natural bond orbitals. In X atoms one lone electron pair is a hybrid orbital with the following fraction of s-component: 38-45% (O), 66-68% (S), and 73-74% (Se). The second lone electron pair is virtually pure pz-AO.     

A microcalorimetric study of the adsorption of NH3 on H, Na-MOR catalysts

The adsorption of NH₃ has been studied on N,Na-MOR samples at 573 K by microcalorimetry. The heat of adsorption as a function of coverage shows a stepwise change. The steps can be attributed to different cationic sites characterized by distinct energy of ammonia adsorption. An increase in the degree of ion exchange increases not only the number of acid sites but their strength, too. The calorimetric measurements made possible to determine the number of acid centers of different strengths.

---

NH₃ N,Na-MOR 573 K. . , . , . .