Analogs of purine nucleosides. 4. 7-Alkylated 9-(2-hydeoxymethyl)guanine

7,9-Disubstituted guaninium hydrohalides were synthesized by the reaction of 9- and 7-(2-hydroxymethyl)guanines with alkyl halides. The effect of the structure of the alkylating agent on the direction and yield of the alkylation reaction was established. The possibility of the conversion of the salts obtained to the free bases in a weakly alkaline medium was investigated. The synthesized compounds were characterized by the UV and ¹H and ¹³C NMR spectra. The ability of the synthesized compounds to inhibit replication of the herpes virus (VPG-1) was demonstrated.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 641–646, May, 1989.     

Thermal radio emission of a homogeneous half-space with a rough boundary

Khar'kov State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 32, No. 8, pp. 927–932, August, 1989.     

On approximating periodic functions by singular integrals with positive kernels

In the two-dimensional case, new approximation characteristics for functions belonging to saturation classes of continuity modules for the spaces L_p of periodic functions are obtained. The problem of approximating a function by an analog of Fejér’s integral in the space of periodic functions square integrable on the period is considered. Bibliography: 5 titles. Dedicated to the 100th anniversary of G. M. Goluzin’s birthday __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 337, 2006, pp. 51–72.     

Modeling the thermomechanical behavior of physically nonlinear materials under monoharmonic loading

We analyze approximate approaches to the modeling of the thermomechanical behavior of physically nonlinear materials under harmonic loading. The approaches are based on various harmonic-linearization schemes and the concept of complex moduli. Mechanical and mathematical features of various schemes are considered. Some modifications of the model are proposed to account for various aspects of material behavior under harmonic loading. The problems of vibration and dissipative heating of physically nonlinear bodies are formulated. The main thermomechanical characteristics are analyzed for some classes of problems.The study was partially sponsored by the State Fund for Basic Research of the Ministry of Education and Science of Ukraine (Grant No. 01.07/00050).Translated from Prikladnaya Mekhanika, Vol. 40, No. 10, pp. 3–34, September 2004.     

Casimir effect at nonzero temperatures in a closed Friedmann Universe

For massive and massless scalar fields with an arbitrary coupling to gravity, we investigate finite-size (Casimir) effects on the free energy at nonzero temperatures in a slowly evolving closed Friedmann universe. The renormalized expressions for the free energy and the resulting energy density and pressure are found and their physical properties are discussed. The equation of state turns out to have the form P=/3 for radiation with arbitrary coupling.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 109, No. 2, pp. 307–320, November, 1996.     

Integrable Multicomponent Perfect Fluid Multidimensional Cosmology II: Scalar Fields

We consider anisotropic cosmological models with a universe of dimension 4 or higher, factorized into n 2 Ricci-flat spaces, containing an m-component perfect fluid of m non-interacting homogeneous minimally coupled scalar fields under special conditions. We describe the dynamics of the universe: It has a Kasner-like behaviour near the singularity and isotropizes during the expansion to infinity. Some of the models considered are integrable, and classical as well as quantum solutions are found. Some solutions produce inflation from nothing. There exist classical asymptotically anti-de Sitter wormholes, and quantum wormholes with discrete spectrum.     

Influence of preliminary treatment on activity and selectivity of Co-alumosilicate catalyst in hydrocarbon synthesis from CO and H2

The temperature and medium of preliminary treatment of 10% Co/SiO ₂·Al₂O₃ influence the activity and selectivity in hydrocarbon synthesis from CO and H₂. Treatment with NH₃ reduces the yield. Increasing the treatment temperature leads to a loss of activity and a change in the composition of hydrocarbons formed. The reason for deactivation is a change in the catalyst surface texture, its adsorptive properties, and the ability to be reduced.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1709–1713, August, 1990.     

Structure and magnetic and electric properties of bismuth niobates doped with d elements: IV. Magnetic behavior of chromium-containing solid solutions with the structure of bismuth niobate, Bi5Nb3O15

The magnetic susceptibility and electrophysical properties of chromium-containing Bi₅Nb_3−3x · Cr_3x O_15−δ solid solutions with the perovskite-like structure were studied. Parameters of exchange interactions in the dimeric clusters of chromium atoms and also the distribution of chromium monomers and dimers in the solid solutions were calculated. Original Russian Text ? N.A. Zhuk, I.V. Piir, A.L. Pimenov, N.V. Chezhina, 2007, published in Zhurnal Obshchei Khimii, 2007, Vol. 77, No. 6, pp. 898–904. For communication III, see [1].     

Analogs of pyrimidine nucleosides

N₁-(-Tetrahydrofuranyl)- and N₁-(-tetrahydropyranyl)uracils and the corresponding 6-azauracils have been obtained by the condensation of bistrimethylsilyl derivatives of uracils and 6-azauracils with-chlorotetrahydrofuran and-chlorotetrahydropyran. The superiority of the silyl method over the mercury method used previously has been demonstrated.For part III, see [9].