Vol 486, No 4 (2019)

Mathematics
Complexity of discrete Seifert foliations over a graph
Kwon Y., Mednykh A.D., Mednykh I.A.
Abstract

In the present paper, we study the complexity of an infinite family of graphs Hn = Hn(G1, G2, ..., Gm) that are discrete Seifert foliations over a graph H on m vertices with fibers G1, G2, ..., Gm. Each fiber Gi = Cn(si,1, si,2, ..., si,ki) of this foliation is the circulant graph on n vertices with jumps si,1, si,2, ..., si,ki. The family of discrete Seifert foliations is sufficiently large. It includes the generalized Petersen graphs, I-graphs, Y-graphs, H-graphs, sandwiches of circulant graphs, discrete torus graph and others. We obtain a closed formula for the number t(n) of spanning trees in Hn in terms of Chebyshev polynomials, investigate some arithmetical properties of this function and find its asymptotics as n → ∞.

Доклады Академии наук. 2019;486(4):411-415
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On bilinear weighted inequalities with Volterra integral operators
Stepanov V.D., Shambilova G.E.
Abstract

Necessary and sufficient conditions on the boundedness in weighted Lebesgue spaces on the semiaxis for bilinear inequalities with Volterra integral operators are given.

Доклады Академии наук. 2019;486(4):416-420
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Sensitivity of functionals of variational data assimilation problems
Shutyaev V.P., Le Dimet F.
Abstract

The problem of variational data assimilation for a nonlinear evolutionary model is formulated as an optimal control problem to find simultaneously unknown parameters and the initial state of the model. The response function is considered as a functional of the optimal solution found as a result of assimilation. The sensitivity of the functional to observational data is studied. The gradient of the functional with respect to observations is associated with the solution of a nonstandard problem involving a system of direct and adjoint equations. On the basis of the Hessian of the original cost function, the solvability of the nonstandard problem is studied. An algorithm for calculating the gradient of the response function with respect to observational data is formulated and justified.

Доклады Академии наук. 2019;486(4):421-425
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Technical Physics
The structure of graphene oxide in polymer matrix and its effect on reinforcement degree of nanocomposite
Kozlov G.V., Dolbin I.V., Nikitin L.N.
Abstract

The methodics of characterization of 2D-nanofiller tactoids structure in polymer matrix of nanocomposite was proposed, which shown that the indicated tactoids are fractal objects with dimension of 1.75-2.16. This variation of tactoids structural state is due to interfacial interactions. It has been shown within the framework of reinforcement percolation theory, that structure of tactoids is single factor, defining reinforcement efficiency is characterized by its ability to create interfacial regions.

Доклады Академии наук. 2019;486(4):426-429
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Mechanics
The deformators of high ranks and the kröner incompatibility tensors with two-dimensional structure of subscripts
Georgievskii D.V.
Abstract

In n-dimensional space (multidimensional continuum) the compatibility equations are derived for the components of the generalized deformators of rank m which are connected with the generalized displacements of rank m - 1 by analogues of the Cauchy kinematic relations (m≥1, n≥2). They may be written in form of equal to zero for all the components of the incompatibility tensor of rank m(n - 2) or for dual to it the generalized Riemann-Christoffel tensor of rank 2m. The number of independent components of these tensors coinciding with the number of compatibility equations in terms of the generalized deformations, is obtained.

Доклады Академии наук. 2019;486(4):430-432
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Chemistry
Hydrogels and sponge materials based on triblock copolymers of lactide and ethylene glycol
Zagoskin Y.D., Grigoriev T.E., Krasheninnikov S.V., Cuevda E.V., Gubareva E.A., Bakirov A.V., Chvalun S.N.
Abstract

New techniques have been developed for the preparation of spongy materials and hydrogels based on triblock copolymers of lactide and ethylene glycol with various molecular structures. The influence of the composition of the initial copolymers and supramolecular structure on their mechanical characteristics and biocompatibility was studied. Cytological studies have shown that all materials have a high level of cell viability (GSP). The possibility of obtaining hydrogels with elastic moduli up to 4460 kPa, a record for such systems, was shown.

Доклады Академии наук. 2019;486(4):433-436
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Reactivity of 2-nitroxysuccinate 3-hydroxy-6-methyl-2-ethylpyridine and reference drugs in model NO-generating systems
Pokidova O.V., Batova E.V., Sadkov A.P., Eremeev A.B., Fedorov B.S., Kotelnikov A.I.
Abstract

The ability of the 2-nitroxysuccinate 3-hydroxy-6-methyl-2-ethylpyridine (I) compound to generate nitrite ions (NO2) and nitrogen monoxide (NO) in model systems with cysteine (Cys) and deoxyhemoglobin (Hb) has been studied. It has been established that there is a more efficient release NO2 and NO from compound I than from Nicorandil. The accumulation rate is 1.5 times higher in the system of Cys with I than with Nitroglycerin. It is shown that, unlike Nitroglycerin, compound I is not reduced by Hb.

Доклады Академии наук. 2019;486(4):437-440
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New proton-conducting polydiimidazopyridine based membrane for ht-pem fuel cell
Ponomarev I.I., Razorenov D.Y., Ponomarev I.I., Volkova Y.A., Skupov K.M., Lysova A.A., Yaroslavtsev A.B.
Abstract

Polydiimidazopyridine was synthesized from 2,3,5,6-tetraaminopyridine and 2,5-dihydroxyterephtalatic acid in polyphosphoric acid and characterized. Polydiimidazopyridine possesses high viscosity, high thermal oxidation resistance and excellent film-forming properties. The polymer was processed from reaction mixture in polyphosphoric acid into proton conducting membranes. The membranes possess higher proton conductivity than for many known membranes at 20-200 °C.

Доклады Академии наук. 2019;486(4):441-445
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Geology
Age and sources of the metasedimrntary rocks of the Tokur terrane in the Mongol-Okhotsk fold belt: results of the U–Pb geoсhronological and Lu–Hf isotope studies
Zaika V.A., Sorokin A.A., Sorokin A.P.
Abstract

This paper presents the results of U–Pb (LA–ICP–MS) and Lu–Hf ­isotope studies of detrital zircons from metasedimentary rocks of the Tokur Terrane. It has been shown that metasedimentary rocks of the Tokur and Ekimchan formations are characterized by similar age peaks of detrital zircons, which indicates a close (or same) age of these formations. The lower age of the sedimentation is determined by the age of the youngest zircons of 326–323 Ma. The upper age boundary is determined of 254–251 Ma, based on the intruded of the Late Permian granitoids. The main sources of zircons in the metasedimentary rocks of the Tokur Terrane are the igneous and metamorphic complexes of the southeast framing of the North Asia Craton. The Tokur Terrane can be considered as a fragment of the Paleozoic accretionary complex, the formation in front of the southeastern margin of the North Asia Craton.

Доклады Академии наук. 2019;486(4):446-450
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The first data on the late pleistocene ostracodes of the Kuray depression (Gorny Altai)
Khazin L.B., Agatova A.R., Nepop R.K., Shurygin B.N.
Abstract

During the field works in the summer of 2018, in the Lena River delta on the Sardakh-Sisse Island, prints of leaf flora belonging to species of broad and small-leaved deciduous trees were found. The prints found by us are confined to the layer of ferruginous sandstones at the base of the section. The following taxa established: Platanus sp., Alnus sp., Fagus sp., Salix sp. In addition, a fossilized fruit belonging to Magnolia sp. The findings allow to conclude that there are mixed forests in the early-middle Miocene in this region, consisting of coniferous, small- and broad-leaved deciduous species of trees and shrubs.

Доклады Академии наук. 2019;486(4):451-454
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Geochemistry
Structural and chemical features of coal-similar wood organic substances of the Devonian and Jurassic periods
Kocheva L.S., Karmanov A.P., Lutoev V.P., Shumilov I.K., Glukhov Y.V., Pokryshkin S.A.
Abstract

The results of investigation of organic matter chemical structure of the coal-similar wood of Devonian and Jurassic geological periods by the methods of IR-, EPR-, chromate-masses-spectrometry and element analysis are presented. It is shown that the investigated samples are the products of the metamorphism of natural lignins, which confirms hypothesis about the important role of lignins in the processes of coal formation.

Доклады Академии наук. 2019;486(4):455-459
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Ultramafic-alkaline-carbonatite complexes as a result of two-stage melting of mantle plume: evidence from the mid-paleoproterozoic Tiksheozero intrusion, Northern Karelia, Russia
Sharkov E.V., Chistyakov A.V., Bogina M.M., Bogatikov O.A., Shchiptsov V.V., Belyatsky B.V., Frolov P.V.
Abstract

Tiksheozero ultramafic-alkaline-carbonatite intrusive complex, like numerous carbonatite-bearing complexes of similar composition, is a part of large igneous province, related to the ascent of thermochemical mantle plume. Our geochemical and isotopic data evidence that ultramafites and alkaline rocks are joined by fractional crystallization, whereas carbonatitic magmas has independent origin. We suggest that origin of parental magmas of the Tiksheozero complex, as well as other ultramafic-alkaline-carbonatite complexes, was provided by two-stage melting of the mantle-plume head: 1) adiabatic melting of its inner part, which produced moderately-alkaline picrites, which fractional crystallization led to appearance of alkaline magmas, and 2) incongruent melting of the upper cooled margin of the plume head under the influence of CO2-rich fluids  that arrived from underlying zone of adiabatic melting gave rise to carbonatite magmas.

Доклады Академии наук. 2019;486(4):460-465
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Features of the impurity composition of diamonds from placers of the northeastern Siberian craton
Shatsky V.S., Nadolinny V.A., Yuryeva O.P., Rakhmanova M.I., Komarovskikh A.U.
Abstract

Diamond crystals from the Istok (25 crystals) and Mayat (49 crystals) placers were studied using the EPR-, IR-, and luminescence methods. The total content of impurity nitrogen in forms of A-, B-, and C (P1)-centers ranges from 50 to 1200 ppm. According to the EPR-spectroscopy, the presence of nitrogen C(P1), N3V nitrogen-titanium OK1, N3, NU1 impurity centers was established in the investigated crystals. Crystals from the Istok placer contain the OK1, N3, NU1 centers, but luminescence attributed to the oxygen-containing centers is absent in the region of 610-670 nm. For the Mayat placer crystals, the reverse situation was observed. The luminescence ascribed to the oxygen-containing centers was detected for 17 crystals, but there were no OK1, N3 and NU1 centers according to the EPR- and luminescence. This result contradicts the arguments of a number of authors about the oxygen nature of these defects. For 5 crystals from the Mayat placer, the nickel impurity was registered. This indicates the presence of ultrabasic paragenesis diamond crystals in this placer.

Доклады Академии наук. 2019;486(4):466-468
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The experimental simulation of ores leaching processes from the deposit Lyubov (Transbaykalia)
Epova E.S., Yurgenson G.A., Eremin O.V.
Abstract

The experiments on the sulfuric acid leaching of main ore-bearing rocks of gold deposit Lyubov (Zabaikalsky Krai) were carried out for the determination of mobile chemical elements in acidic landscapes weathering processes. The chemical composition of ore samples, major and minor minerals have been determined. The composition of the ore and rock-forming minerals were studied by X-ray diffraction and chemical analyses and electron microscopy. According to the results of the experiments has been revealed a group of mobile chalcophile elements (Pb, Zn, Cu, Cd), V group elements (As, Sb, Bi) associated with sulfide minerals and a group of rare and trace elements. It has been determined that with contents below clarkes abundance the lanthanides, cesium, chromium, germanium are rapidly moved in acidic solution.

Доклады Академии наук. 2019;486(4):469-474
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Geophysics
Excitation of seiches in ice at port water area of the sea of Okhotsk
Dolgikh G.I., Kovalev D.P., Kovalev P.D.
Abstract

Long term observations of sea waves with one second discreteness in the port harbor of Sea of Okhotsk (Sakhalin island) at a depth of about two meters under the ice were carried out using autonomous wave recorders in 2009-2017. Spectral analysis of the data showed the presence of several significant peaks on the periods from 2 to 15 seconds in the spectra for the moments of strong swell at sea. These peaks are caused by wave processes that are generated due to the nonlinear transformation of the swell coming in ice. The numerical simulation of the reaction of the dynamic system - the water area described by the Duffing equation, depending on the parameters included in the equation and determined from experimental observations, is carried out. It is shown, including using the Poincare mapping that the amplitude of external forcing has the greatest influence on the transition of the system to chaos.

Доклады Академии наук. 2019;486(4):475-479
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To the estimation of damping of seismic body waves in the Elbrus volcanic area
Sobisevich A.L., Zvereva A.S., Likhodeev D.V.
Abstract

The problem of the origin and development of hazardous endogenous processes in the southern regions of Russia is considered. According to the results of the analysis of data obtained by means of the regional seismic network, there were estimated the Q-factor of the layered geophysical medium as well as damping of elastic body waves. The new results testifying in favor of the hypothesis on the likely area of upcoming fluid-magmatic processes in the Elbrus volcanic region are considered.

Доклады Академии наук. 2019;486(4):480-484
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Geography
Extreme transport velocities of Antarctic Bottom Water flow through the deep Vema Channel
Morozov E.G., Frey D.I., Neiman V.G., Makarenko N.I., Tarakanov R.Y.
Abstract

In April 2017 and in October 2018, a Russian expedition on the R/V “Akademik Sergey Vavilov” in the South-West Atlantic carried out measurements of temperature, salinity, and velocity over a standard section across the deep Vema Channel at 31(градус) 12(минут) S. Extremely high and extremely low velocities and transports of Atlantic Bottom Water (AABW) in the entire history of our observations over this section were found. In 2017, the maximum speed over the section reached 55 cm/s, and in 2018, it did not exceed 30 cm/s. In 2018, a core of high velocities in the bottom layers of the channel characteristic of the AABW flow was not found.

Доклады Академии наук. 2019;486(4):485-488
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The accurate calculation of the geodetic heights of the celestial body’s surface points relative to the triaxial ellipsoid
Fleis M.E., Nyrtsov M.V., Borisov M.M., Sokolov A.I.
Abstract

A sphere or ellipsoid of revolution are usually used for approximation of the physical surface of the Earth. In some cases, a triaxial ellipsoid is used. The calculation of the geodetic height of points on the Earth’s surface is carried out mainly by approximate methods using the formulas for the dependence of spatial rectangular coordinates x, y, z on geodesics B, L, H. However, there are small bodies of the Solar system, for example, Eros 433 asteroid, for which such variants of the first approximation are incorrect, since in this case both first approximations are not small quantities. This article proposes a fundamentally new approach to calculating the geodesic height relative to the triaxial ellipsoid, based on the joint use of the normal equation for a surface passing through a given point and the equations of the surface itself. The method is reduced to solving the sixth-degree equation by the Sturm method and the fourth-degree equation by the Ferrari method.

Доклады Академии наук. 2019;486(4):489-493
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Oceanology
Space-time ph variability in the Black Sea
Polonsky A.B., Grebneva E.A.
Abstract

Based on the archival data for the period from 1956 to 2010, space-time pH changes in the Black Sea upper layer are analyzed. In the surface layer, a statistically significant decreasing in the pH value (at a level of -0.06 pH units per 50 years) was found. It is mostly due to the growing concentrations of carbon dioxide in the atmosphere. Intermediate layers are characterized by a negative pH trend which absolute value more than fivefold exceeds the surface pH trend. Likely reason of the pH decreases here is a long-term upward moving of acidic waters with a typical velocity of ~1 m per year.

Доклады Академии наук. 2019;486(4):494-499
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Biochemistry, biophysics, molecular biology
NAD(P)H: FMN-oxidoreductase functioning under macromolecular crowding: in vitro modeling
Govorun A.E., Esimbekova E.N., Kratasyuk V.A.
Abstract

The functioning of Vibrio fischeri NAD(P)H: FMN-oxidoreductase (Red) under conditions of macromolecular crowding (MMC) modeled in vitro by adding biopolymers (starch and gelatin) was studied. The dissociation rate constants and the activation energies of dissociation of Red to the subunits were calculated; the process of denaturation of Red was analyzed. It was shown that the functioning of Red both under conditions of MMC and diluted solutions is the same. The result refutes the common belief that due to MMC the stabilization of enzymes’ native conformation occurs in vivo when compared to in vitro.

Доклады Академии наук. 2019;486(4):500-503
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Bacteriochlorophyll interaction with singlet oxygen in membranes of purple photosynthetic bacteria: does the protective function of carotenoids exist?
Makhneva Z.K., Ashikhmin A.A., Bolshakov M.A., Moskalenko A.A.
Abstract

The direct action of singlet oxygen on the bacteriochlorophyll (BChl) of light-harvesting complexes in the membranes of four types of purple non-sulfur and sulfur photosynthesizing bacteria with and without carotenoids has been studied. It has been found that BChl in carotenoid-less samples is generally more resistant to the action of singlet oxygen compared to the control. It is assumed that carotenoids are not needed to protect BChl of bacterial light-harvesting complexes from singlet oxygen, and in the classic work of Griffith et al. [1] the apoptosis process in carotenoid-less mutant cells, which involves the destruction of complexes, the appearance of monomeric BChl and generation of singlet oxygencaused by BChl, followed by BChl oxidation, was mistakenly attributed to the protective function of carotenoids.

Доклады Академии наук. 2019;486(4):504-508
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Molecular dynamics modeling of the interaction of cationic fluorescent lipid peroxidation-sensitive probes with the mitochondrial membrane
Nesterenko A.M., Kholina E.G., Lyamzaev K.G., Mulkidzhanyan A.Y., Chernyak B.V.
Abstract

Cardiolipin (CL) plays a central role in lipid peroxidation (LPO) of the mitochondrial inner membrane due to higher content of unsaturated fatty acids in CL in comparison with the other phospholipids. CL oxidation plays an important role in the regulation of various intracellular signaling pathways and its excessive oxidation contributes to the development of various pathologies and, possibly, participates in the aging process. Mitochondria-targeted antioxidants containing triphenylphosphonium cation (TPP+) effectively protect CL from oxidation. It is assumed that fluorescent probes on the basis of the C11-BODIPY fluorophore sensitive to LPO and containing TPP+ can selectively register CL oxidation. To test this possibility, we carried out a molecular dynamic simulation of such probes in a model mitochondrial membrane. It is shown that the probes are located in the membrane at the same depth as the unsaturated bonds in CL molecules sensitive to oxidation. Increasing the length of the linker that binds the fluorophore and TPP+ residue has little effect on the position of the probe in the membrane. This indicates the possibility of modifying the linker to increase the selectivity of the probes to CL.

Доклады Академии наук. 2019;486(4):509-513
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Functional comparison of short and long isoforms of the TRF2 protein in Drosophila melanogaster
Osadchiy I.S., Georgiev P.G., Maksimenko O.G.
Abstract

The TRF2 protein (TBP-related factor 2) can substitute for TBP in the TFIID complex forming alternative transcription initiation complexes for TATA-less promoters, including promoters of histone H1 and required for transposon repression piRNA-clusters. The Drosophila trf2 gene codes for two isoforms: a “short” and a “long” one, in which the same short TRF2 sequence is preceded by a long N-terminal domain. Here, we demonstrated that the long TRF2 isoform has greater functional activity then the short isoform by expressing each of them in reduced rate under the endogenous promoters. Expression of the long isoform alone doesn't affect neither the flies` viability nor the sex ratio. Expression of the short isoform alone leads to the phenotype described for the trf2 gene insufficiency and derepression of transposable elements, that is, decreased viability, violation of homologous chromosome pairing and segregation, and apparent female-biased sex ratio.

Доклады Академии наук. 2019;486(4):514-518
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