Communicated by Academician Vyacheslav I. Yanchevskii

In a number of cases the minimal polynomials of the images of unipotent elements of non-prime order in irreducible representations of the exceptional algebraic groups in good characteristics are found. It is proved that if p > 5 for a group of type E₈ and p > 3 for other exceptional algebraic groups, then for irreducible representations of these groups in characteristic p with large highest weights with respect to p, the degree of the minimal polynomial of the image of a unipotent element is equal to the order of this element.

Communicated by Corresponding Member Valentine V. Gorokhovik

In the paper the Lipschitz-like properties of solution mapping of lower-level problems for bilevel programs are studied and sufficient conditions for partial calmness are proved on the basis of these properties.

Communicated by Academician Vladimir A. Kulchitsky

A rapid method for correction of the influence of light scattering and absorption in biological tissues on their fluorescent images is proposed. To speed up the calculations of a medium transfer function a regression and analytical descriptions of light fields at the fluorescence excitation and emission wavelengths are used. The required information on the absorbance of a medium is extracted from components of its colored image. The effectiveness of the method is estimated on the images of biological phantoms obtained by the Monte Carlo simulations.

Communicated by Corresponding Member Fedor P. Korshunov

A comprehensive study of the crystal structure, magnetic and elastic properties of layered cobaltite Sr_0,8Y_0,2CoO_2,65 with a perovskite-type structure was carried out. It is established that the magnetic ordering in this composition is accompanied by a structural transition. The Neel temperature (T_N) is 375 K. The unit cell volume at TN increases as a result of the orbital ordering in the CoO₅ pyramids connected by the vertices in the anion-deficient layers. The main magnetic structure is an antiferromagnetic G-type structure with a small ferromagnetic component. The non-collinear magnetic structure is stabilized by the ferromagnetic bonds between the cobalt ions in the CoO₅ pyramids. Co³⁺ ions in the both layers are in the mixed low-spin (LS)/high-spin (HS) state. The temperature dependence of the electrical resistivity has a semiconductor character. The large resistivity value and small magnetoresistance indicate a good stability of the semiconductor antiferromagnetic state of this composition.

A fibrous anion exchanger with ternary amino groups of dimethylaminopropylamine was obtained on the base of a polyacrylonitrile fiber by the previously proposed method of catalytic amination of nitrile groups. A fibrous anion exchanger with strong base functional groups was synthesized on the base of this material by the reaction of alkylation of its groups with epichlorohydrin solutions. Their exchange capacities, acid-base properties, sorption of acetic acid vapors from air with different relative humidity were determined. The boundary and optimal conditions of application of the obtained ion exchangers in the processes of air purification from acetic acid and the dynamic characteristics of filtration layers were established.

The features of the molecular structure and morphology of polyethylene (PE) and polyvinyl chloride (PVC) based coatings, deposited from the products of repeated electron beam dispersion of the original polymer, are determined. Macromolecules coatings obtained by repeated dispersing of PE, contain a high concentration of unsaturated bonds and short-chain branching. The coating is formed by highly dispersed lamellar, “spiral” formations. The effect of the electron beam on PVC initiates the processes of dehydrochlorination, the formation of a polyconjugated structure. Recycled PVC-based ratings contain mainly graphite-like structures and polyene fragments, have regular pores of 300-700 nm in size, high abrasion resistance, which determines their effective use as an antibacterial layers matrix.

Three chemical compounds presenting functional mimetics of neutralizing anti-HIV-1 antibody N6 were identified by an integrated approach including virtual screening, high-throughput docking and molecular dynamics. Using molecular docking, the identified compounds are predicted to be able to block three key regions of the HIV-1 gp120 protein by formation of a wide network of intermolecular contacts with the glycoprotein residues critical for the virus binding to primary receptor CD4. It is shown that the complexes of these compounds with gp120 exhibit low values of dissociation constant and Gibbs free energy, which validates a high efficacy of intermolecular interactions stabilizing these supramolecular structures. Based on the data obtained, the identified compounds are assumed to form promising basic structures for the development of novel, potent and broad anti-HIV-1 drugs mimicking structural and functional properties of the cross-reactive neutralizing antibody N6.

Screening of 27 varieties of soft spring wheat, included in the State register of varieties of the Republic of Belarus for 2019 for the presence of alleles of genes of puroindolines Pina-D1 (Pina-D1a and Pina-D1b) and Pinb-D1 (Pinb-D1a, Pinb-D1b, Pinb-D1d) was carried out using аllele-specific markers. As a result of the research made, it is shown that almost all studied varieties of spring wheat are solid-grained, since their genotype revealed mutant alleles: Pinb-D1b, Pinb-D1c, Pinb-D1d. The exception was the Belarusian varieties of wheat Madonna and Sabina that were the carriers of alleles of wild type Pina-D1a and Pinb-D1a. In the varieties of spring wheat Darja (Belarus), Laska (Belarus), Lubava (Belarus), Slavyanka (Belarus, Russia), Triso (Germany), Sorbas (Germany), Korynta (Poland), Verbena (Poland), Venera (Serbia), Septima (Czech Republic) identified the mutant allele Pinb-D1b. The carriers of the allele Pinb-D1c are the varieties Rostan (Belarus), Rassvet (Belarus), Toma (Belarus), Vasilisa (Belarus), Moneta (Belarus), Nagrada (Belarus), Sudaryna (Belarus), Ladja (Belarus, Russia), Quattro (Germany), Kvintus (Germany), Koksa (Poland), Mandaryna (Poland), Serenada (Poland), Korynta (Poland), Verbena (Poland) and Canuck (France). Amplification fragments characteristic of the mutant allele Pin-bD1d were present in he wheat variety Eureka (Belarus). Varieties of soft spring wheat with the identified alleles of the puroindoline genes Pina-D1 and Pinb-D1 can serve as a starting material for a purposeful formation of the genotype of the variety with specified values of endosperm hardness and softness of the endosperm, and it can also be used as a positive control in molecular genetic studies.

Usage of electric fields for forming a certain cellular response finds application in various fields of biology and medicine. The efficiency of the methods based on the electric field action was discussed repeatedly. However, the process of developing stimulation protocols is being complicated by the absence of the specification of the precise mechanism of the electric stimulation action upon cells in the culture. Thus, the identification of signal transduction mechanism in cells under the electric field action is of current interest. The objective of this work is to investigate the role of potassium potential-dependent channels in forming the cellular response at long-term electrical stimulation. Studies were carried out using glioma cells C6. The pulsed electric field with the strength of 3-20 V/m, with 2 ms biphase pulses and with a frequency of 10 Hz was used for electric stimulation. 4-Aminopyridine was used for inhibitory analysis. It was shown that the change in the membrane potential under the electric field action takes place involving the potassium potential-dependent ion channels. It was revealed that the use of a potassium potential-dependent ion channels inhibitor partially levels the field effects. Thus, potassium potential-dependent channels play a significant role in the processes of signal transduction in cells at long-term electrical stimulation of the culture of cells.

Communicated by Academician Aleksey V. Matveev

The reconstruction of environmental changes in the southeast of Belarus during the last 14700 cal. BP is based on the results of palynological, radiocarbon, isotope and lithological studies of Lake Staroje deposits. Climatic fluctuations, fires and human activities played a significant role in the transformation of the vegetation cover. The beginning of the lacustrine sedimentation was dated circa 16000 cal. BP. The intensification of erosion processes on the water catchment area was marked by an increase in the mineral material flow into the lake. These events have a positive correlation with the climate cooling and humidity phases in the Late Glacial and Early Holocene, and in the Late Holocene with anthropogenic impact stages. The traces of the episodic human activity were dated to 5800 cal. BP, while the expansion of farming and pasturing areas began at 3000 cal. BP Currently the consequences of human activities (including drainage of bogs) are reflected in the treeless landscapes adjacent to the lake.

The Pripyat area of the Late-Devonian magmatism (PALDM) covers the eastern and northeastern territories of the lithosphere segment of the same name. The space asymmetry of the PALDM relative to the Pripyat paleorift graben is the fundamental feature of the western side of the Pripyat-Dnieper-Donets aulacogen. The explosive and effusive-intrusive magmatism manifested within this territory in the Late Devonian was determined to a large extent by the premagmatic and synmagmatic destruction of the earth’s crust within the riftogenesis area and a junction with West-Dnieper rift pillow (RP) formed by the core intrusions of the mantle plumes in the region of the Bragin-Loyev Saddle. The synrift shear zones of tension within the PALDM were the tracers for the magmatic melt motion from the deep magmatic chambers towards the upper crustal “chambers” of lowered pressure. Their general geological position is marked by the West-Dnieper RP.

Today there are many manufacturers of orthodontic archwires composed of a nickel-titanium (TiNi) alloy with different elastic-force characteristics. A limited number of orthodontic archwires is available for initial tooth alignment, since reactive stresses do not always satisfy the condition 160 ≤ σc ≤ 200 MPa. The use of orthodontic archwires with polymer coatings having better aesthetics is increasing. However, they show excessive wear and color change during a long-term orthodontic treatment. The aim of this paper is to study and optimize the functional characteristics of superelastic archwires composed of Ti-50.8 аР % Ni alloy with TiN coatings deposited at varying deposition times. A three-point bending test was carried out to evaluate the functional properties. The distance between the supporters was 10 mm. The archwires were subjected to bending at a temperature of 23 ± 3 °C. Each test was continued until deformation of 1.5; 3; 4.5 and 6 % was reached. It has been found that titanium nitride coatings deposited on the Ti-50.8 at. % Ni surface alloy by the vacuum-plasma method act as the barrier layer to prevent the release of nickel ions into biological environment. Heat treatment (~400 °C) during deposition allows the required elastic-force characteristics and functional properties of the material to form. The optimal reactive stress (160-200 MPa) and the reverse martensitic transformation temperature occurred near room temperature can be obtained due to an appropriate selection of the deposition parameters. In the martensitic phase at room temperature, the archwire can be deformed. When the archwire sample is placed in oral cavity and heated to temperatures above 30 °C the material is in the superelastic state. Further research is needed in terms of coating stability during deformation when the material in superelastic state, as well as conducting corrosion testing, studying biocompatibility of archwire samples with titanium nitride coatings in order to successfully implement the proposed technology in dental practice. The prototypes of orthodontic TiNi archwires with protective and decorative TiN coatings will be obtained for medical application.

This work is a continuation of the work, where the results of the theoretical study of the formation of the electromagnetic field in the explosion of the cumulative charge were presented and the hypothesis of the formation of an electromagnetic pulse in the collision of a high-speed flow of particles with a metal barrier was put forward. In the present work, the cumulative charge was used to disperse powder microparticles to speeds of 2500 m/s and to study the processes of collision of high-speed particle flows with an obstacle. The purpose of the work is to study the features of electromagnetic radiation in the collision of a high-speed flow of particles with a solid. The study of the resulting pulse of electromagnetic radiation was carried out according to the developed method by measuring the magnetic field induction using Hall sensors. The average value of the magnetic field induction is 45.9 MT. Registration of the ionizing component and evaluation of the radiation energy were determined by the intensity of photodetector illumination (x-ray film). Evaluation of the particle energy along the path length in the emulsion gives a value of 80-100 MeV. It is shown that the process of high-speed collision and interaction of the microparticle flow. with a metal barrier is accompanied by a number of effects that have not yet been studied. As a result of the research, practical results are obtained that confirm the previously proposed hypothesis and allow to supplement the understanding of the nature of the origin of electromagnetic radiation in the collision of a high-speed flow of particles with a metal barrier in the conditions of their penetration.

Communicated by Academician Oleg G. Penyazkov

Mean velocity, fluctuations, spatial correlations and wave number spectra were calculated and analyzed by the LES method using the software OpenFOAM for solution of the task of the developed 3D turbulent boundary layer. The layer was formed in water flowing in the 50 х 125 х 850 mm flat channel (height, width and length, respectively) at a mean entrance velocity of 0.3 m/s that results in the Reynolds number based on the half channel height equal to 7500. The velocity profile at the channel entrance was set by the law 1/7. The turbulent parameters were calculated on two coordinates: y⁺ = 10 and 40, i. e. in the buffer and logarithmic regions of the boundary layer. The study showed that the vortex structures were generated in the buffer region; they were still identified at the beginning of the logarithmic region (y⁺ = 40). These structures form vortex packets whose scale in the transverse direction is much less than their length. The vortex packets weakly interact with each other in the transverse direction, which results in an almost constancy of the energy spectrum within a broad wave number range.

Communicated by Academician Alexander I. Lokotko

Based on the great factual material, the article retraces the formation of ideological, social and cultural attitudes and regulations that implemented the socialist realism methodology in theory and practice of the Belarus folklore studies. In the 1930s, the socialist realism established itself as an ideology of the folk art studies, as a result of which it virtually lost its independence and entered the system of new conceptual coordinates in social dialogue. The article broadly examines the establishment of an extensive and inherently unique project known as the “Soviet folklore” in the academic and cultural discourse of Belarus. Belarusian folklorists were claimed to be incorporated in the process of finding and representing the works of the new socialist folklore art authorized and ideologically defined by those in authority. The strategies of adherence of intellectuals to the social realist discourse during the period of 1930-1950 included various forms of compromise between science, traditional culture holders, mass recipients of the Soviet culture and the authorities. The article states that the methodological crisis in social realist science has expressed itself through the unification of folklore and the established canon (i. e. the corpus of texts of explicit ideological modality), the elimination of the whole layer of uncensored folklore texts from the scope of the study; the ignoring of the dialect nature of traditional culture in collection and editing practices; the blurring of the research subject in folklore studies due to the legitimized role of an active amateur artist, as well as amateur art and punli-cation integrated to the research paradigm. The article employs new facts from the history of folklore studies that prevent the one-way interpretation of the specific features of the Soviet period folklore studies and expand the problem field of the modern science.