Source: http://nasb.gov.by/eng/publications/dan/dan54_5.php
Timestamp: 2019-04-19 23:02:43+00:00

Document:
Kandratsiuk A. P., Matus P. P.
Summary: In the present paper the questions of monotonicity, global stability and blow-up of solutions of difference schemes approximating semilinear parabolic equations with nonlinear source of quadratic type have been investigated. Corresponding statements are proved only in the assumptions on the input data. The performed numerical experiments illustrate theoretical results.
Summary: A method of extension of connected, simply connected solvable Lie groups, which act transitively and locally effectively on a given compact solvmanifold, is presented.
Kostyukova O. I., Kurdina M. A.
Summary: In the article, new necessary optimality conditions for optimal control problems with discontinuous right-hand side are obtained. Comparison of the optimality conditions obtained in the article with some other known results is carried out. Some illustrative examples are presented.
Beresnevich V. V., Bernik V. I., Goetze F.
Summary: We investigate the distribution of resultants of integral polynomials of degree n and height bounded by Q. Within this class of polynomials we obtain a sharp and effective lower bound for the number of pairs of polynomials with their resultant bounded by some power of Q.
Summary: An explicit iteration method for solution of the operator equations in the Hilbert space is proposed. Convergence of the method is proved in the case of an a priori choice of the number of iterations, and error estimates are obtained. The cases of non-uniqueness and convergence of the method in power norm are investigated. For the method under consideration, the application of the neighboring approximation rule and of the residual stop rule is substantiated.
Khodos S. P., Lomovtsev F. E.
Summary: The smoothness of the weak solutions of the Cauchy problem for the hyperbolic triad-term operator-differential equation of Euler--Poisson--Darboux type with variable domains of operator coefficients is investigated. For the first time the criteria of the correct solvability with respect to the initial data of the operator-differential equation of Euler--Poisson--Darboux type with variable domains and of the timesingular equation of string vibrations under the time-dependent boundary condition are obtained.
Karpenko V. A., Mogilevich V. N.
Summary: The strict mathematical formulation of the diffraction problem allowing a sequentially improved solution is found.
Summary: The consistent biquaternion formulation of the basic equations of polarization optics, including the orthonormal system of eigenvectors of arbitrary Jones matrices, was done. It is shown that the stability group of the Jones matrices defines the structure of the topological phase acquired by the Jones vectors at light propagation in media with periodically varying parameters. The observed structure of the topological phase can be essential for the management of elementary qubit which is modeled using a two-level quantum system with losses, for example, caused by the environment.
Pozdnyakov D. V., Komarov A. F., Komarov F. F.
Summary: A physical-mathematical model and a computer code for numerical calculation of the energy spectrum of IR photodetectors based on GaAs/AlxGa1-xAs superlattices have been developed. A dependence of an optimal GaAs layer thickness on an aluminum fraction in the GaAs/AlxGa1-xAs layer has been obtained.
Torgashov V. I., Gert E. V., Zubets O. V., Kaputskii F. N.
Summary: A considerable fraction (20-21 % w/w) extractable with water at 120 0C from the stalks of annual plants consists mainly of polyuronide hemicelluloses. Based on the experimental data obtained in the study, the high chemosorption activity of the plant tissue towards mineral soil components, including radionuclides, is due to the presence of the above mentioned substances.
Vasilevskaya A. V., Sergeev G. V., Gilep A. A., Usanov S. A.
Summary: Cytochrome P450s (P450) are likely involved in the main metabolic functions of mycobacteria and might be possible targets for new agents to overcome multiple-drug resistant tuberculosis. We compared the sequences of M. tuberculosis and M. bovis, which allowed determining differences in the genes encoding cytochrome P450. The results indicate the relative conservatism of the structure and the composition of the P450 mycobacteria M. tuberculosis complex, which is, apparently, due to the participation of these enzymes in the growth and development of pathogenic mycobacteria. In addition, we conducted the sequencing and the analysis of point mutations of genes P450 in different isolates of M. tuberculosis and M. bovis, as well as of forms of mycobacteria that are resistant to anti-TB drugs. Location of amino acid substitutions in the substrate-access channel and enzyme active site can indicate the potential involvement of these substitutions in determining the specificity of P450 mycobacteria in relation to the substrate or inhibitor, which leads to a more favorable life activity of mycobacteria in a particular organism, or due to the increasing degree of resistance to the action of certain groups of anti-TB drugs.
Nichick M. N., Voitekhovich S. V., Lesnikovich A. I., Ivashkevich O. A.
Summary: A simple method for synthesis of stable silver nanoparticles has been reported. This method is based on reduction of silver trifluoroacetate with sodium borohydride in two-phase system in the presence of available 1-R-5-thiotetrazoles as stabilizing agents. The influence of phase transfer catalyst Aliquat 336 on properties of resulting nanoparticles has been investigated. It was observed that addition Aliquat 336 to the reaction mixture containing 1-adamantyl-5-mercaptotetrazole leads to the formation of bigger nanoparticles in comparison with analogue synthesis in the absence of phase transfer catalyst. The particles obtained are attractive for preparation of catalysts and electronic materials based on “naked” nanostructures.
Summary: Water-soluble semi-conductor luminescent nanoparticles of cadmium selenide (CdSe), covered with a passivation layer of zinc sulfide (ZnS), are investigated. The influence of the nature of nanoparticles external functional-protective shell consisted of organic ligands on the stem cell activity is studied Bifunctional thiols, such as cysteine, thioglycolic acid, 11-mercaptoundecanoic acid and SH-terminated polyethyleneglycol have been used as shell stabilizing CdSe/ZnS nanoparticles in water solutions. To impart biocompatible properties to CdSe/ZnS nanoparticles the external shell composed of 11-mercaptoundecanoic acid has been modified by biotinylated bovine serum albumin. It is shown that nanoparticles with the studied functional-protective shells easily penetrate into stem cells, but only their conjugates with protein do not affect the activity of the cells.
Bazhanov D. P., Yatsevich K. K.
Summary: Thirteen strains of fluorescent pseudomonads from the Belarusian collection of non-pathogenic microorganisms were identified by determining similarities of 16S rRNA gene sequences, their phylogenetic analysis and by taking into account the results of genotyping. It was found that bacteria, identified as P. fluorescens from the phenotypic tests, are highly heterogeneous genetically and mostly do not belong to this species Thus, the application of the molecular genetic methods is required for identification of fluorescent pseudomonads . Species affiliation of five strains was determined: BIM B-187 -- to P. fluorescens, BIM B-100 -- to P. orientalis, BIM B-98 and BIM B-158 -- to P. cedrina, BIM B-228 -- to P. vancouverensis.
Urbanovich O. Yu., Kazlouskaya Z. A., Kartel N. A.
Summary: An important part of modern apple breeding is the development of disease and pest resistant cultivars. Marker-assisted selection has at its disposal methods enabling detection and selection of genotypes with resistance genes. The given study dealt with determining the mildew resistance gene Pl1 presence in the collection containing 130 apple cultivars and species. SCAR marker AT20-450 was used for identification. The marker was detected in the cultivars Chulanovka, Dolgo, Alamata and the species M. ´ cerasifera, M. sargentii, M. ´ robusta, M. baccata. Hybrid seedlings containing a marker for gene Pl1 were produced on the basis of the cultivar Chulanovka . Hybrid seedlings containing Sd-locus, conferring resistant to rosy leaf-curling aphid, and Vf gene resistance to scab were selected among them.
Mastykin A. S., Evstigneev V. V., Golovko V. A., Apanel E. N., Voytsekhovich G. Yu.
Summary: Nocuous influences (attacks, intrusions) on normally proceeding processes in various areas of practical activities induce to search for new, more refined methods of protection against them. Normal Internet work and normal vital activity of a living organism in surrounding conditions are exposed to such attacks. Informative methodological approaches to the problem of protection against nocuous calls, both in a society and in a separate living organism, can be similar and even identical. Here and there, the main is to unmask and to determine a pathogenic agent. In this context, in the present work the solution of the problem of protection against nocuous attacks to normal blood supply of the brain by convergence with the neuronet approach to protection against Internet network virus attacks is defined specifically. For this purpose, steady classification decisions on image recognition are, first of all, necessary. In our medical research this means correct diagnostics. Using the available initial sample training data, the 100% recognition in four classes of recognition of images, as which the subtypes of transient ischemic attacks (TIA) act, has been obtained . However on the test samples the result has appeared more modest, slightly exceeding the unstable 75 % level, which is, apparently, caused by an insufficient number of the verified clinical cases of subtypes TIA in training sample.
Balashevich T. V., Nikandrov V. N., Lukashevich V. S.
Summary: The cytoplasmic membranes of rat newborns spinal cord cells and rat C6 glioma cells on the glycine-specific receptor presence in vitro have been investigated. By the immunohistochemical method the presence of glycine-specific sites was shown on glial and neuronal cells. The immunoreactivity to glycine receptor al- and a2- subunits has diffusive localization in gliocytes, and concentration localization -- in neurons, which is probably determined by receptor functional differences of this type cells.
Garetskii R. G., Karataev G. I.
Summary: On the basis of the complex analysis of the data of drillings and geophysical materials a new geological section of the top part of the earth crust of the northeast of Belarus is presented. It is shown that the Preriphean and Riphean normal-sedimentary platform cover is spread not of Archean--Early Proterozoic by the crystal base as it was considered earlier, but by the Late Proterozoic kuaziplatform of the volcanogenic-sedimentary layer. Actually, the crystal base lies down more deeply at the depth of 2.0--2.5 km. A new scheme of tectonic division into districts of the northeast of Belarus, excluding the Early Archean Vitebsk granulite massif, is offered.
Summary: The known mantle electrical conductivity anomalies of the East European Platform are confined to the areas of plate paleosubduction and collision. In the case of low heat flux values, the mantle electrical conductivity can increase due to a special composition of the mantle material, where unstable amphiboles occur in the depth range from 80 to 120 km.
Abramenko T. N., Anisovich A. G.
Summary: The methods of thermodynamics of irreversible processes have been used for investigating the mechanism of dissipating magnetic energy in the ferromagnetic system in reversible and irreversible processes. The similarity criterion for generalization of experimental magnetocaloric effect data is obtained. The relation for calculation of hysteresis losses in ferromagnetic materials is derived.
Vitayz P. A., Zhornik V. I., Vyblyi Yu. P., Kukareko V. A.
Summary: The influence of addition of ultradispersed diamonds in the chromizing electrolyte on the formation of structure of composite coatings is studied. It is shown that the introduction of ultradispersed diamond particles into the electrolyte smoothes the microrelief of the surface coating and decreases the size of chromium microspheroids (grains). The minimum size of subgrains (200--250 nm) was found in the coatings deposited from the electrolyte with the concentration of ultradispersed diamond particles of about 5 g/l. The phenomenological model for formation of composite electrochemical coatings modified by ultradispersed diamond particles, which relates the grain size of the electrochemical coating to the electrodeposition process parameters, is offered.
Astapchik S. A., Maliutyn V. B., Ustsinovich D. F.
Summary: The new mathematical model based on the use of stationary diffusion equations is suggested for description of abrasive surface processing using elastic tools with polymer-abrasive fiber composites. Calculation is made of approaching the contacting surfaces as well as of the curve of workpiece bearing surface.

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