Vol 484, No 5 (2019)

We construct existential monadic second order sentences that have no limit probabilities on binomial sparse random graph G(n; n^–α) . For α < , the constructions have only one monadic variable.

For level sets of -mappings of Carnot manifolds to Carnot–Caratheodory spaces, we introduce an adequate local metric characteristic. Moreover, for mappings defined on Carnot groups, we construct a special adapted basis in the preimage such that it assigns a suitable local sub-Riemannian structure on a complement of a kernel of a sub-Riemannian differential to the initial sub-Riemannian structure in the image.

A number of phenomena associated with the formation of macroscopic structures due to the high interaction intensity of elements of spatially homogeneous systems and due to linear spatial transport in spatially inhomogeneous systems are addressed. A characteristic feature of the considered class of problems is the violation of the continuity of the operators describing the evolution of a system in natural norms determined by local conservation relations.

An inversion problem for LTI hyperoutput time-delay system is considered. For such systems canonical form with isolated zero dynamics is obtained, system invariant zeros and their relation to spectral observability of zero dynamics subsystem are investigated. Using this results, inversion algorithm is suggested for time-delay systems.

The problem of large deformations in a combined nonlinear elastic hollow cylinder under internal and external pressures, loaded with a longitudinal force and torque at the end faces, is under consideration. The combined cylinder is a tube with the internal and external coatings in the form of prestressed hollow circular cylinders. An exact solution to the problem is found, which is valid for any model of isotropic incompressible elastic materials.

Conversion possibility of the chemical energy of combustion products of a hydrogen–oxygen mixture into electrical energy with the use of continuous spin detonation has been demonstrated for the first time in an MHD system. The specific conductivity of detonation products in the region of rotation of the detonation front was measured to be ~3 · 10^–2 Ω^–1 m^–1. The structure of transverse detonation waves was examined, their velocity was measured (2220 ± 50 m/s), and the flow in their vicinity was studied.

The films of supersaturated Cd_xPb_1-xS solid substitutional solutions (0 < x < 0,25) with thickness 0.6–1.0 μm were synthesized by chemical bath deposition. The dependences of dislocation density, crystallite sizes and texture coefficient versus the cadmium content in the films were determined by analyzing X-ray diffraction spectra with the use of modified method of Williamson—Hall (MWH).

By using the magnetic resonance imaging method the nontrivial character of water absorption was demonstrated for the first time in highly porous ceramic materials. The effect of hygroscopic memory was found out which is that the preferable concentration of absorbed water in certain areas within the sample persists regardless the subsequent sample wetting history. Coating the oxide fibres with fluorine-containing hydrocarbons in supercritical CO₂ in order to hydrophobize the material has been shown to affect substantially the water transport within the sample that can be referred to as an effective approach to protect the porous materials from humid environment. The results obtained demonstrate the advantages of the magnetic resonance imaging in studying the water absorption processes and visualization of water pathways in highly porous ceramic materials.

The CePO₄ – SiO₂ – NaF – Fe₂O₃–Nb₂O₅ system is characterized by a wide area of two immiscible melts. As the temperature in the system increases, the region of incompressibility of melts increases. Mutual solubility of immiscible melts is low and is 3–5% by weight. The decrease in the melting point of the components is due to chemical reactions between SiO₂ and NaF and between cerium orthophosphate and sodium fluoride. New previously unknown phases were established in the system: double salt of cerium and sodium, fluoride phosphate of cerium and sodium and phase with high content of niobium. Niobium oxide is distributed between the silicate melt, silicate balls, which is part of the phosphate fluoride melt and a phase with a high content of niobium. Cerium is concentrated in the phosphate-salt melt, where it is found in the double salt of cerium and sodium and the fluoride phosphate of cerium and sodium.

The results of U–Pb geochronological studies of quartz syenites of the Kumystin complex of the Bolshoi Karatau ridge in southern Kazakhstan are presented and their late Neoproterozoic (717 ± 4 Ma) age is substantiated. Kumystin syenites complex together with rhyolites and basalts of the Kainar Formation are the youngest formations taking part in the basement of Karatau-Dzhebagly precambrian massif and formed in the second half of Cryogenian. The data set about the ages of the youngest complexes taking part in the basement of precambrian massifs of the Western part of the Central Asian belt indicates that the ending of magmatic activity within various massifs occurred asynchronously during the Neoproterozoic.

The study of two varieties of pseudotachylytes (PST) in granitoids of the Riphean complex on the Barents Sea coast of the Kola Peninsula (Rybachii and Srednii peninsulas) and in metapsammite of the Paleoproterozoic complex in the Northern Ladoga region by a few independent analytical methods has made it possible to establish that they belong to different genetic forms, such as mechanically crushed rocks and melting products, respectively. As for the melting differences, we have given a detailed description of the mineral and material transformations of the original rock into the PST glass matrix and obtained evidence for the initial melting out of the micaceous eutectics with its subsequent shift to the granite type. The conclusion has been made on the most likely formation of molten PST due to frictional rock melting under rapid rise of its blocks from a depth of 12–15 km to the crustal surface (less than 3 km) along the faults of presumably seismogenic nature. It is suggested that crushing and frictional melting can be complementary, rather than mutually exclusive processes, and the formation of molten PST is commonly preceded by the mechanical rock crushing stage.

The melting in the system of aluminosilicate (granite) melt — fluoride salt melt at T = 800–1200˚C and P = 1–2 kbar was experimentally investigated. The data on the phase composition of silicate-salt systems and the character of the interphase distribution of ore components are presented. The partition coefficients of rare-earth elements between the granite melt and fluoride phase at 900–1200˚C, P = 1–2 kbar were obtained. It is shown that REE enrich the fluoride phase with respect to the silicate melt. Elements of the (V, Nb, Ta), (Ti, Zr, Hf) groups almost always prefer a silicate melt relative to fluoride.

Experimental data are presented to show that the spatial and temporal variability of the composition of river waters cannot be explained solely by the influence of sources and effluents of the substances and that there are additional significant factors that support or even initiate the dispersion of the concentration of pollutants here. This variation is reflected in the resources and the economic characteristics of the rivers; so identification of its reason is important. Thus, the hydrodynamic structure of the water flow is studied by analyzing the complete system of equations of fluid motion mechanics. The completed work allowed us to show that the elements of this structure are waves, vortices, and highly gradient layers (ligaments), presumably creating the described dispersion effect. Further investigation of the relationship of the precise hydrodynamic and hydrochemical structures of river waters will contribute to better understanding of the water-environmental processes, ensuring the perfection of water management methods.

A comprehensive analysis of waveforms of seismic and infrasonic vibrations from the earthquake that occurred on December 5, 2014, in the water area of Lake Hovsgol was performed. The analysis showed that the infrasonic signal recorded at the Tory station (Geophysical Observatory of the Institute of Solar-Terrestrial Physics, Russian Academy of Sciences) was formed by the sources of three generation types: local, secondary, and epicentral. The obtained results allow us to propose the model of epicentral infrasonic signal generation by flexural waves from an elastic ice membrane on the surface of Lake Hovsgol.

Large-scale atmosphere–ocean interaction in the Atlantic sector of the Arctic Ocean is analized. New studies demonstrate that the variability of Atlantic water inflow into Nordic seas is driven largely by the leading mode of year-to-year variations in the ocean – atmosphere system–the North Atlantic Oscillation (NAO). A new vision of the effect of the NAO on the hydrophysical characteristics of the Norwegian and Barents seas is offered.

The abundance and biomass of picophytoplankton, the total concentration of chlorophyll “a”, and the contribution of the picofraction to chlorophyll “a” were studied in the Laptev Sea in 2017. These were the first data for the western sea area. An increase in picophytoplankton abundance in the eastern part of the sea in comparison with that in 1991 was not revealed. The contribution of the picofraction to chlorophyll “a” was the highest (to 56%) in areas with a low total concentration of chlorophyll “a”.

Biopsy material of patients with malignant and benign breast diseases was examined. HRG mRNA expression was detected in 70% of cases in biopsy material obtained from patients with nonspecific invasive carcinoma and in 66.7% of cases in biopsy material of patients with benign breast diseases. Immunohistochemical analysis revealed expression of collagen II, the beta-1 integrin, and E-cadherin – markers of epithelial–mesenchymal transition. The use of RT-qPCR combined with immunohistochemical study made it possible to identify atypical cells, which can be regarded as precancerous changes, in individual patients.

The PBAF(SWI/SNF) multiprotein complex, which changes the chromatin structure, is widely involved in the regulation of eukaryotic gene expression. A specific component of this complex is the PHF10 protein, which is involved in recruiting this complex to chromatin. We showed that the PHF10 expression in cells of different lines is activated by the c-MYC oncogene. Since PHF10 stimulates cell proliferation, its c-MYC-dependent activation in cancer cells should lead to an increase in their proliferation rate.

The effect of estradiol (E₂), progesterone (P₄), and oncostatin M (OSM) on the differentiation of CD4⁺ T cells to T regulatory (Treg) lymphocytes and T helpers 17 (Th17) was investigated. The possibility of revision of the T cell receptor in these subpopulations by evaluating the expression of RAG-1 recombinase was also studied. E₂ at concentrations characteristic of pregnancy trimester I, but no P₄ or OSM, increased the Treg level. Combination of sex steroids with OSM increased the percent of CD4⁺FOXP4⁺ cells and enhanced RAG-1 expression in these cells, thus promoting the development of immune tolerance during pregnancy. In the study of Th17 such effect of the hormones and OSM was not detected.

In vitro, endothelium-dependent relaxation mechanisms of smooth muscle cells of the bovine mesenteric lymph node capsule have been studied. The addition of L-NAME and indomethacin to physiological saline inhibited the production of endothelium NO and prostacyclin. In this solution, tetraethylammonium chloride and TRAM-34 increased the tone of the precontracted lymph nodes. Thus, in bovine mesenteric lymph nodes there is an relaxation mechanism mediated by endothelial hyperpolarization, realized by activating Ca²⁺-dependent K⁺-channels of large- and intermediate conductance.