Vol 484, No 4 (2019)

Mathematics
On the complexity of some problems of searching for a family of disjoint clusters
Kel'manov A.V., Pyatkin A.V., Khandeev V.I.
Abstract

We consider some consimilar problems of searching for disjoint subsets (clusters) in the nite set of points in Euclidean space. In these problems, it is required to maximize the minimum subset size such that the value of each intracluster quadratic variation would not exceed a given fraction (constant) of the total quadratic variation of the points of the input set with respect to its centroid. In the paper, we have proved that all the problems are NP-hard even on a line.

Доклады Академии наук. 2019;484(4):387-392
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Disorder indicator for nonstationary stochastic processes
Kislitsyn А.A., Kozlova A.B., Korsakova M.B., Orlov Y.N.
Abstract

The properties of a statistic called a self-consistent stationarity level of nonstationary time series are examined in this work. It is shown that a change in this statistic can be treated as a disorder in the nonstationarity properties of the series. The significance level of decision making is estimated, characteristic periods in a non-stationary stochastic process are detected, and an optimal sample size for constructing indicators in stochastic control problems is determined. A disorder indicator for electroencephalogram data from epilepsy patients is studied as a practical application.

Доклады Академии наук. 2019;484(4):393-396
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Spectral deformation in a problem of singular perturbation theory
Stepin S.A., Fufaev V.V.
Abstract

Quasi-classical asymptotic behavior of the spectrum of a non-self-adjoint Sturm–Liouville problem is studied in the case of a one-parameter family of potentials being third-degree polynomials. For this problem, the phase-integral method is used to derive quantization conditions characterizing the asymptotic distribution of the eigenvalues and their concentration near edges of the limit spectral complex. Topologically different types of limit configurations are described, and critical values of the deformation parameter corresponding to type changes are specified.

Доклады Академии наук. 2019;484(4):397-400
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Fast trie-based method for multiple pairwise sequence alignment
Yakovlev P.A.
Abstract

A method for efficient comparison of a symbol sequence with all strings of a set is presented, which performs considerably faster than the naive enumeration of comparisons with all strings in succession. The procedure is accelerated by applying an original algorithm combining a prefix tree and a standard dynamic programming algorithm searching for the edit distance (Levenshtein distance) between strings. The efficiency of the method is confirmed by numerical experiments with arrays consisting of tens of millions of biological sequences of variable domains of monoclonal antibodies.

Доклады Академии наук. 2019;484(4):401-404
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Informatics
Generalization of Kravchenko—Kotelnikov theorem by spectra of compactly supported infinitely differentiable functions
Budunova K.A., Kravchenko V.F., Pustovoit V.I.
Abstract

New generalization of KravchenkoKotelnikov theorem by spectra of compactly supported infinitely differentiable functions is discussed. These functions are solutions of linear integral equations of special form. The spectrum of is a multiple infinite product of the spectra of atomic functions. dilated by the argument. Constructed generalized series has fast convergence. This property is confirmed by the presented truncation error bound formula and the results of a numerical experiment.

Доклады Академии наук. 2019;484(4):405-409
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Theoretical physics
Nonlinear wave and cavitation processes and their effect on the mechanical properties of viscous solutions
Ganiev S.R., Kuznetsov I.S., Shmyrkov O.V.
Abstract

In this paper, we present experimental results on the effect of nonlinear wave and cavitation processes occurring in flowing working parts of hydrodynamic generators of vortex and flat types with flow bodies of various shapes on the physicomechanical properties of a clay suspension. The model of the vortex-type generator with tangential and radial channels for feeding the working fluid of the generator, which is a flat channel with three bodies of flow around a cylindrical shape, was subjected to research.

Доклады Академии наук. 2019;484(4):410-414
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Mechanics
Modeling the angular momentum control of small spacecraft with a magnetic attitude control system
Kulkov V.M., Egorov Y.G., Firsyuk S.O., Terentyev V.V., Shemyakov A.O.
Abstract

The problem of modeling the angular momentum control modes of small spacecraft using electromagnetic systems interacting with the Earth’s magnetic field is considered. The electromagnetic system control law has been constructed for various compositions of measurable parameters. A set of scale factors has been formed to investigate the angular momentum control mode of dynamically similar models. Based on a dynamical test stand, we have carried out experimental studies to model the angular motion dynamics of small spacecraft with a magnetic attitude control system.

Доклады Академии наук. 2019;484(4):415-419
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Mechanism of formation of Prandtl’s secondary flows of the second kind
Nikitin N.V., Pimanov V.O., Popelenskaya N.V.
Abstract

Turbulent flow in a tube of square cross section is investigated numerically. The concentrated longitudinal vortices responsible for the occurrence of secondary flows are studied. It is shown that the longitudinal vortices are formed as a result of nonlinear interaction of turbulent pulsations in which the pulsations of the longitudinal component of vorticity are specially adjusted in phase with the pulsations of the longitudinalvelocity component. A physical interpretation of this mechanism is given.

Доклады Академии наук. 2019;484(4):420-425
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On the application of the Green‒Nagdi equations for the simulation of wave flows with undular bores
Ostapenko V.V.
Abstract

The basic conservation laws in the Green–Nagdi model of shallow-water theory are derived from the two-dimensional integral conservation laws of mass and the total momentum describing the plane-parallel flow in an ideal incompressible fluid above a horizontal bottom. This conclusion is based on the concept of a local hydrostatic approximation, which generalizes the concept of the long-wavelength approximation and is used for analyzing the applicability of the Green–Nagdi equations in modeling the wave flows with undular bores.

Доклады Академии наук. 2019;484(4):426-430
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Chemistry
Synthesis and self-assembling amphiphilic diblock-copolymers of (2,3,4,5,6)-pentafluorostyrene
Chekurov K.E., Barabanova A.I., Blagodatskikh I.V., Lokshin B.V., Peregudov A.S., Abramchuk S.S., Khokhlov A.R.
Abstract

Amphiphilic diblock-copolymers (DC) of (2,3,4,5,6)-pentafluorostyrene and 2-hydroxyethyl methacrylate were prepared for the first time by two-step reversible addition–fragmentation chain transfer (RAFT) polymerization. The morphology of films of diblock-copolymers that have a composition close to equimolar was studied by transmission electron microscopy. The observed microphase separation and formation of spherical nanodomains is not typical for equimolar diblock-copolymers and seems to result from hydrogen bonding between the hydroxyl and carbonyl groups (OH···OH and C=O···HO) in poly(2-hydroxyethyl methacrylate) blocks. Obviously, it is the ability of diblock-copolymers to self-organization is the cause of formation of fabric coatings with low surface energy (γ = 11.9 mJ/m2) and relatively large water contact angles (θН2О = 120±6°) and diiodmetane (θCH2I2 = 93±2°).

Доклады Академии наук. 2019;484(4):431-435
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Chemical Technology
Hierarchically structured, highly porous nickel synthesized in sintering–evaporation process from a metal nanopowder and a space holder
Gnedovets A.G., Zelenskii V.A., Ankudinov A.B., Alymov M.I.
Abstract

This paper reports on the creation of a highly porous material with a hierarchical structure using powder metallurgy methods based on nickel nanopowder and ammonium bicarbonate NH4HCO3 as a space holder.

Доклады Академии наук. 2019;484(4):436-440
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Physical chemistry
Kinetics of chemical processes in the human brain. Trigger effect and self-stabilization of N-acetylaspartic acid
Varfolomeev S.D., Semenova N.A., Bykov V.I., Tsybenova S.B.
Abstract

A kinetic model was proposed for the response of nerve tissue to an external signal stimulus. The model is based on the views of a multistep and non-linear nature of the dynamic variation of the concentrations of N-acetylaspartic acid and N-acetylaspartate in the human nerve tissue. The substrate inhibition effect in this system is a necessary factor for the self-stabilization of N-acetylaspartate as a key brain metabolite. The existence of three stationary states accounts for the trigger behavior of the system.

Доклады Академии наук. 2019;484(4):441-446
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Electronically mediated reactions in metal thermal reduction of molybdenum and tungsten oxide compounds
Kolosov V.N., Orlov V.M.
Abstract

The reduction of tungsten and molybdenum oxide compounds (WO3, MoO3, MgWO4, MgMoO4, and CaMoO4) with calcium vapor at 800860°С and a residual argon pressure of 510 kPa in reactor have been studied. As previously during the reduction with magnesium vapor, the spatial separation of the reaction products was observed, namely, the major portion of the calcium oxide formed in the reaction was deposited outside the reaction zone. A specific feature of the reduction of MgWO4 and MgMoO4 is that the magnesium is first replaced by calcium. The resulting magnesium metal acts as a reducing agent, and the magnesium oxide, along with calcium oxide, forms a crust on the surface of the reaction mass. Analysis of the results shows that the reduction of oxide compounds with magnesium and calcium vapors at a residual argon pressure in reactor of more than 5 kPa proceeds via the electronically mediated reaction mechanism without direct physical contact between the reactants.

Доклады Академии наук. 2019;484(4):447-450
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Effect of “cobalt–carbon nanotubes” catalysts on anthracene coking
Chesnokov V.V., Chichkan A.S., Parmon V.N.
Abstract

Coking of anthracene at 400–600°C in the presence or in the absence of a cobalt catalyst supported on carbon nanotubes (CNTs) was studied for the first time. The coking products were examined by X-ray diffraction and electron microscopy. The CoO-CNTs catalyst considerably (by 50°C) decreased the temperature of the onset of coking and accelerated the coke formation. The presence of CoO-CNTs changed the coke morphology. Whereas coking of pure anthracene affords ~1 micron spherical particles of poorly crystallized carbon, in the presence of the catalyst, a carbon “coating” covering the CNT surface is formed.

Доклады Академии наук. 2019;484(4):451-454
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Geology
Age and sources of the Lower Mesozoic metasedimentary rocks of the Un'ja-Bom terrane in the Mongol-Okhotsk fold belt: results of the U–Th–Pb geohronological (LA–ICP–MS) AND Sm–Nd isotope studies
Zaika V.A., Sorokin A.A., Kovach V.P., Sorokin A.P., Kotov A.B.
Abstract

The results of the U—Th—Pb geochronological studies indicate that in the Un’ja-Bom terrane the youngest peaks on the relative probability curves of ages are 207 and 212 Ma for zircons from the metasiltstone of the Kurnal formation and from the metasiltstone of the Amkan formation. Similar age estimates for the youngest peaks were obtained for the detrital zircons from the metasedimentary rocks of the Tukuringra terrain of the eastern part of the Mongol-Okhotsk belt, which indicates that the Lower Mesozoic flyschoid complexes in the structure of this belt are developed much wider than is currently believed. The results obtained in our U—Th—Pb geochronological and Sm—Nd isotope geochemical studies suggest’s that the sedimentary rocks material was carried to the sedimentation basin mainly from the continental massifs of the Amur superterrane.

Доклады Академии наук. 2019;484(4):455-459
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Geochemistry
Experience in applying a local analysis an sulfur isotopes in the ore sulfides of the largest deposits of Bodaibinsky Synclinoria (Eastern Siberia)
Goryachev N.A., Ignatiev A.V., Velivetskaya T.A., Budyak A.E., Tarasova Y.I.
Abstract

The experience of LA—ICP determining of the isotopic composition of sulfur pyrite and arsenopyrite of gold deposits of the Baikal-patomsky plateau is considered. The technique is characterized. It is shown that all the studied samples have values δ34S and δ33S strictly corresponding to the law of mass-dependent fractionation of sulfur isotopes. A regular alleviation of the isotopic composition of sulfur of pyrite as its crystals grow for Sukhoi Log and the isotopic homogeneity of pyrite and pyrrhotite of the Golets Vysokhashiy deposit are established. It is concluded that the possible role of metamorphism of the Mamsko-Oronsky belt in the formation of isotopic homogeneity of ore sulfides.

Доклады Академии наук. 2019;484(4):460-463
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A new compound of the (K,Na)3Ca8Si6[Si4O12]3 charoite substrate
Kashaev A.A., Ivanova L.A., Medvedev V.J., Uschapovskaya Z.F.
Abstract

As a result of experimental studies on the interaction between a charoite substrate and host lamprophyres of microcline-arfvedsonitic composition, a new (K,Na)3Ca8Si6[Si4O12]3 compound has been obtained with a new type of radical Si2[Si4O12] found in its crystalline structure а = 15.2613 (3) Å, I2/13, Z = 4. The chain-shaped Ca-octahedra connected through common faces encircle a radical and close in a K-octagon. In contrast to charoite with banded-tube radicals, an isometrically-island silicon radical is identified.

Доклады Академии наук. 2019;484(4):464-467
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Early Cambrian age and crustal source of granitoids of the Goryachinsky pluton (North Baikal area): geodynamic implications
Rytsk E.Y., Sal'nikova E.B., Yarmolyuk V.V., Andreev A.A., Bogomolov E.S., Lebedeva Y.M., Velikoslavinskii S.D., Anisimova I.V., Plotkina Y.V., Fedoseenko A.M.
Abstract

The article presents the results of U-Pb in zircon and Nd-isotope study of the adakite granites of the Goryachinsky pluton, exposed along the Baikal coast in the section of termination of the package of shear tectonic plates of the Baikal-Muya belt. The Early Cambrian age of granitoids, which is unusual for the Northern Baikal region, is 545 ± 6 Ma. According to the authors, new geological and isotopic data indicate the formation of the studied granitoids at the final stage of the Late Baikal shear tectogenesis, which caused the manifestation of adakite magmatism within the Baikal-Muya belt.

Доклады Академии наук. 2019;484(4):468-471
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Variations of the 238U/235U isotope ratio in metasedimentary rocks and evidence of changes in sedimentation conditions during the Ediacaran period of the Neoproterozoic
Chugaev A.V., Chernyshev I.V., Budyak A.E., Mandzhieva G.V., Sadasyuk A.S., Gareev B.I.
Abstract

The isotopic composition of uranium is a new geochemical indicator that facilitates reconstruction of the redox conditions of geological processes. In this paper the results of study of the 238U/235U isotope ratio in the Neoproterozoic metasedimentary rocks of the Baikal–Patom fold belt (Northern Transbaikalia) were obtained using the MC-ICP-MS method and 233U+236U double spike. The scale of 238U/235U ratio variations (δ238U = –0.37 to –0.11‰) is within the range of (–0.39 to +0.15‰), typical of metasedimentary terrigenous rocks of marine origin. In terms of the δ238U values, uranium of the BPB rocks studied is heavier than seawater uranium (δ238U = –0.41 ± 0.03). There is a correlation between the δ238U value in the rocks and their position in the stratigraphic section. Variations of the 238U/235U ratio in the terrigenous-carbonate sequences of BPB indicate that the sedimentation conditions changed and euxinic conditions were established in the course of evolution of the paleobasin in the Late Ediacarian Period.

Доклады Академии наук. 2019;484(4):472-477
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Geophysics
Mapping of interplate coupling in the Kamchatka subduction zone from variations in the earthquake size distribution
Vorobieva I.A., Soloviev A.A., Shebalin P.N.
Abstract

The geometry of supposed coupling zones in the Kamchatka subduction zoneis determined by the earthquake size distribution based on earlier revealed relationship between its shape and rate of inelastic deformations. In the areas of higher aseismic slip, a break of linearity in earthquake size distribution is observed owing to the deficit of large earthquakes. Zones of higher coupling between the oceanic and continental plates are characterized by an excess of large earthquakes and an inverse bend in the earthquake size distribution. The mapping results of the bend value agree with the coupling zones distinguished from satellite geodetic data and inversion of marigrams.

Доклады Академии наук. 2019;484(4):478-481
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Attenuation of gravity waves in fast ice
Levin B.V., Kovalev P.D., Kovalev D.P., Kirillov K.V.
Abstract

The attenuation coefficients of sea waves in ice in the coastal zone of the Sea of Okhotsk with periods from 4 to 30 s were estimated as a function of their wavelength based on observations. We used the model dispersion relation for these waves in ice and calculated the theoretical attenuation coefficients. We compared them with those from the data of experiments based on the relation of the spectral energies of waves in ice-free water and in ice. It is possible to use the estimated attenuation coefficients for waves of different periods to calculate the distance of wave propagation in fast ice with the critical amplitude where ice breaking is possible.

Доклады Академии наук. 2019;484(4):482-486
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Oceanology
Features of the distribution of abnormal gas geochemical fields in the Red River rift (Gulf of Tonkin, South China Sea)
Shakirov R.B., Hung D., Syrbu N.S., Anh L., Obzhirov A.I., Borzova O.V., Okulov A.K., Nam B., Diep N., Dong M., Legkodimov A.A., Shakirova M.V., Ponomareva A.L., Bakunina M.S.
Abstract

This paper reports the results of the third Russian–Vietnamese expedition (POI FEB RAS and the Institute of Marine Geology and Geophysics, Vietnam Academy of Science and Technology) in the Gulf of Tonkin, South China Sea (April 2016) and field work outcomes from 2016-2017. The studies revealed new specific features of the distribution and origin of gas-geochemical fields in sediments within the rift zone of the Red River along a 150-km profile. Four zones with high amplitude anomalies of hydrocarbon gases, helium, hydrogen, carbon dioxide, and carbon monoxide were revealed. The distribution of the anomalies reflects the tectonic structure of the area and points to the presence of several lithospheric sources of gases including gases of deep origin. The studies were carried out within the scope of the Joint Vietnamese–Russian Laboratory for Marine Geosciences (POI FEB RAS and the Institute of Marine Geology and Geophysics, Vietnam Academy of Science and Technology). The article is dedicated to the year of friendship between Russia and Vietnam.

Доклады Академии наук. 2019;484(4):487-490
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Biochemistry, biophysics, molecular biology
Biotechnological method of preparation and characterization of recombinant antimicrobial peptide avicin a from Enterococcus avium
Balandin S.V., Finkina E.I., Nurmukhamedova E.K., Tagaev A.A., Umnyakova E.S., Kokryakov V.N., Shvets V.I., Ovchinnikova T.V.
Abstract

Avicin A is a bacteriocin from the gram-positive bacterium Enterococcus avium. It exhibits a high microbicidal activity against bacteria of the genus Listeria, a causative agent of the severe human infection listeriosis. We developed a biotechnological method for obtaining avicin A and characterized its structure and biological activity. We also proposed a possible mechanism of the antimicrobial action of avicin A.

Доклады Академии наук. 2019;484(4):491-494
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Effect of transcription on the white gene enhancer integrated into the intron
Erokhin M.M., Mikhailova A.V., Georgiev P.G., Chetverina D.A.
Abstract

We demonstrate that passing-through transcription suppresses the activity of the white gene enhancer integrated into the intron. At the same time, the SV40 transcription terminators flanking the transgene can completely remove the inhibitory effect of transcription.

Доклады Академии наук. 2019;484(4):495-497
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Experience of the application of antiseptics for the treatment of biological matrixes of rat lung
Kuevda E.V., Gubareva E.A., Basov A.A., Krasheninnikov S.V., Grigoriev T.E., Gumenyuk I.S., Dzhimak S.S., Kachanova O.A., Chvalun S.N.
Abstract

In order to select the optimal method for disinfecting the scaffolds prior to decellularization using morphological methods (studying the biomechanical strength of extracellular matrix fibers) and analyzing chemiluminescence in rats, the effect of octenisept and chlorhexidine was studied at different concentrations on the biological matrices of the lungs before and after decellularization. Chlorhexidine at a dilution of 1:10 possessed the least damaging properties for the matrix and most contributed to the decontamination of the cages for further storage and experimental studies.

Доклады Академии наук. 2019;484(4):498-502
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The new plant expression system for the development of vaccines against papillomaviruses
Salyaev R.K., Rekoslavskaya N.I., Stolbikov A.S.
Abstract

To enhance the synthesis of the main antigenic coat proteins L1 of high risk oncogenic papillomaviruses types HPV16, HPV18, HPV31 and HPV45, the sequence of the gene encoding the cucumber mosaic virus replicase (RdRP CMV) was inserted into the genetic construct. This inclusion has made possible to increase highly the production of these antigenic proteins to 25—27 µg per 1 mg of total soluble protein of transformed tomato fruit.

Доклады Академии наук. 2019;484(4):503-506
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Gene dunce localization in the polytene chromosome of Drosophila melanogaster long span batch of adjacent chromosomal structures
Khoroshko V.A., Pokholkova G.V., Zykova T.Y., Osadchiy I.S., Zhimulev I.F.
Abstract

The molecular and chromosomal localization of the dunce gene was studied. This gene (167.3 kb) consists almost entirely of introns, in which a cluster of seven short tissue-specific genes is located. On the basis of the results of FISH analysis of the gene fragments, we established that the dunce gene is located within nine chromosomal structures (four bands and five interbands), which contradicts the common idea that genes are located in only one structure (band or interband) or at the boundary of these structures. Our results are quite unexpected and original and greatly expand the current understanding of the genetic organization of interphase chromosomes.

Доклады Академии наук. 2019;484(4):507-510
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