Vol 484, No 1 (2019)
- Year: 2019
- Articles: 25
- URL: https://journals.eco-vector.com/0869-5652/issue/view/756
- DOI: https://doi.org/10.31857/S0869-56524841
Mathematics
Spectral properties of ordinary differential operators with involuton
Abstract
Let P and Q be ordinary differential operators of order n and m generated by s = max{n; m} boundary conditions on a nite interval [a; b]. We study operators of the form L = JP + Q, where J is the involution operator in the space L2[a; b]. We consider three cases n > m, n < m, and n = m, for which we dene concepts of regular, almost regular, and normal boundary conditions. We announce theorems on unconditional basis and completeness of the root functions of operator L depending on the type of boundary conditions from selected classes.
Classical and generalized of a mixed problem– solutions for a non-homogeneous wave equation
Abstract
This study follows A.N. Krylov’s recommendations on accelerating the convergence of the Fourier series, to obtain explicit expressions of the classical mixed problem–solution for a non-homogeneous equation and explicit expressions of the generalized solution in the case of arbitrary summable functions q(x), ϕ(x), y(x), f(x, t).
Mathematical physics
Slow and rapid oscillations in an optoelectronic oscillator model with delay
Abstract
The local dynamics of an optoelectronic oscillator model characterized with feedback delay is investigated. In the neighborhood of the zero equilibrium state, normalized equations are constructed, which are boundary value problems depending on the continuumal parameter. Such problems are used to determine the asymptotic solutions of the original nonlinear system, mainly the frequencies and amplitudes of the components, in the form of a combination of slow and fast oscillations.
Physics
Absorption of laser radiation by metals at formation superficial nanostructure
Abstract
The absorption mechanism of laser radiation is offered by a metal surface at the formation of superficial nanostructure. Principally, the heterogeneous character of such absorption depends on formation in the old, excited structure of zones of absorption. It is shown herein that the absorption process of laser radiation by metals can have a nonlinear character.
Mechanics
Theory of block structure in the strength problem of galleries and constructions with multiple connections
Abstract
It is shown that the boundary-value problem for a layered medium with parallel multiple cavities is reduced to the Riemann vector problem. To solve it, a factorization method is developed, which makes possible to construct the solution to be built in arbitrary approximations.
Block finite-element model of layer-by-layer analysis of three-layer stress–strain state in general irregular shells of rotation of double curvature
Abstract
This study proposes a finite-element block approach to building a new, refined model for layer-by-layer analysis of the stress–strain state of generally irregular sandwich shells of revolution with double curvature. A core material model is developed for the first time for such shells, based on more precise statements compared to those of similar common models; it allows the avoidance of the discontinuity of generalized displacements on the surfaces of an interface with base layers and switching to simpler models depending on the problem statement. Using the proposed model, it is possible to create an allowance for the changes in the properties and parameters of the stress–strain state in all the three coordinates, to which the shell is assigned, and to obtain a solution within the specified statement for different shell shapes and boundary conditions of layers, including in the case of discontinuity.
Chemistry
Formation of nanoscale sodium dodecahydro-closo- dodecaborate Na2[B12H12] on silicate matrix surface
Abstract
The method of nanoscaled sodium dodecahydro-closo-dodecaborate Na2[B12H12] synthesis is presented. The composite is heated to 200°C to yield the desired product, forming with the introduction of triethyl- ammonium salt [Et3NH]2[B12H12] into the silicate matrix of a sodium liquid glass. The morphology and phase composition of the synthesized sample are studied through SEM and X-ray diffraction methods, in comparison to those of a standard salt sample Na2[B12H12]. Based on the obtained data, the sample under study is an amorphous composite, on the surface of which nanoscale crystals of Na2[B12H12] form.
Morphologic, chemical, and spectral analyses of combustion products of micro- and nano-dispersed particles of aluminium borides
Abstract
This study presents the findings of an investigation of flame propagation in air suspension of nanodispersed polyboride particles, and provides spectral, morphological, and mass-spectrometric analyses of condensed combustion products generated during an air suspension combustion.
Chemical Technology
Synthesis of Ni nanoparticles with controlled pyrophoricity and mean size
Abstract
This study establishes that nickel formate decomposition in an argon flow at 209°C and subsequent processing of the obtained nanopowder in a hydrogen flow within a specified time interval, make it possible to control the pyrophoricity and average size of Ni particles.
Physical chemistry
Hydroosmotic pressure
Abstract
This work proposes the term “hydroosmotic pressure” to define hydrostatic pressure emerging from an osmotic process during solvent diffusion through membranes. The usage of this term potentially clears the ambiguity of the term “osmotic pressure,” referring to the concentration of dissolved solids in a solution regardless of the existence of hydrostatic pressure. Hydroosmotic pressure is the difference between hydrostatic pressures on either side of the membrane; thus, the term “hydroosmotic pressure” allows for the most correct definition of many processes associated with osmotic phenomena.
Geology
Early Ordovician alkali-ultramafic Zhilandy complex (Central Kazakhstan): structure and age of formation
Abstract
U–Pb geochronological study of amphibole-bearing quartz monzodiorites of the alkali-ultramafic Zhilandy complex in Central Kazakhstan, whose formation is deduced at the Early Ordovician era (479 ± 3 Ma). The obtained data indicate three stages of intra-plate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic stage of alkali syenites of the Karsakpay complex intrusion, Early Cambrian stage of ultramafic-gabbroid plutons of the Ulutau complex formation, and Late Cambrian–Early Ordovician stage of formation of the Zhilandy complex and Krasnomay complex intrusions.
Features of ore formation of gold deposits of Glukharinsky District (Prikolyma Terrain)
Abstract
This study discusses new data on the isotopy of δ34S, δ18O, microelements, and rare earth elements (REE) in the Au deposits of the Glukarinsky ore cluster. The identified geochemical features are indicative of the reducing conditions of ore deposition, participation of magmatogenic fluid in ore formation, and the enclosing rocks being the possible sources of ore material. Isotope studies indicate that the ore-forming fluid has a mixed, metamorphogenic–magmatogenic composition. The obtained results make it possible to qualify the examined objects as Au deposits associated with granitoid intrusives.
Geology, mineral associations, and composition of native gold in mineral deposits of Taimyr–Severnaya Zemlya Orogen
Abstract
Diverse grain sizes and morphologies, chemical composition, and productive mineral associations of native Au from new mineralizations within two mineragenic areas (Mininsk–Bolshevik miogeocline, Shrenk–Faddeev accretionary) in Western and Central Taymyr, are indicative of a complex, multi-component composition of ore-forming systems and differences in the physical and chemical conditions of formation of gold ore mineralization. The obtained data on the characteristics of native Au, combined with peculiarities of the geological structure of the objects, suggest a significant gold ore potential of central sector of the Russian Arctic.
Geochemistry
Local source of detritus for the rocks of the Ai formation (a basal level of the strata-typical lower Riphean sequence, the Bashkir uplift, the Southern Urals) derived from results of U–Pb dating (LA—ICP—MS) of detrital zircons
Abstract
This study presents the results of U–Pb dating of detrital zircons separated from rocks of the Ai formation. A provenance-signal of local source with an age of approximately 2.07 Ga is derived and an effect of the Ordovician magmatic episode impact on the sedimentary strata is revealed.
Formation conditions of host rocks and veins productive deposits of the Astrakhan gas-condensate field
Abstract
This study examines one- (gas) and two-phase (aqueous solution–gas) inclusions in the calcite of the Cheremshanskian Horizon of the Bashkirian stage at a depth of 4,215–4,217 m in the Pravoberezhnaya-1 well. Homogenizing temperature is within 100–134 °C, which is likely close to the temperature of mineral formation. Calcite vein formation involves calcium bicarbonate fluid enriched in Mg chloride. It was established the calcite inclusions contain carbon dioxide, methane, and hydrogen sulfide. The gas composition of the inclusions in limestone is distiuguished of its high carbon dioxide concentration but rather low methane and hydrogen sulfide concentration.
Geophysics
The effect of seismic deformation mechanisms on fluid migration in accumulation area of gold ore concentrations
Abstract
This study investigates the effect of mechanisms of paleode formations during the period of fluid inflow into the accumulation sphere of gold concentrations. Such mechanisms are believed to correspond to DC- and NDC- type seismic mechanisms, whose main influence on fluid migration lies on the formation of different, relative to fluid regime parameters, structural and hydrodynamic organizations of the ore-forming system, and fluid flow control within the area of the accumulation of ore concentrations.
Deep velocity structure of the southern edge of the Siberian Craton and Baikal Rifting
Abstract
The velocity structure of the southern edge of the ancient Siberian craton has been modeled to an 80-km depth based on teleseismic records of a P-receiver function method (P–S). The correlation between the deep and the surface structure determined through modeling is indicative of the submeridional convergence of the south-western edge of the Siberian craton with the Central Asian mobile belt. A sublatitudinal crust extension in the contact zone caused by such convergence may initiate Baikal rifting at the craton’s southeastern edge.
Shock wave as possible mechanism for the generation of abnormally high accelerations during the M = 9.0 Tohoku earthquake on march 11, 2011
Abstract
This study proposes a mechanism for the generation of anomalously high accelerations (over 1g, maximum up to approximately 3g) recorded during the 2011 Tōhoku earthquake (Mw = 9.0). Soil behavior in the fault zones of the earthquake is examined based on the records of vertical groups, and the earthquakes “atypical” model is determined: shear moduli increased during strong motions, which are indicative of soil strengthening, and then decreased. That which can be explained by an assumption of soils being subjected to some additional impact. Accelerogram curves show a decrease in the duration and an increase in the intensity of strong motions with distance from the earthquake source, which may be indicative of superposition of seismic waves and generation of shock waves by a rapidly moving source — the tip of the fracture in the earthquake source.
Biochemistry, biophysics, molecular biology
Аnticholinesterase and antioxidant activity of new binary conjugates of (с)-carbolines
Abstract
This study presents the synthesis of binary tetrohydro-γ-carbolines with ditriazol spacers of varying length, which exhibit anticholinesterase and antioxidant activity, as compared to the original Dimebon prototype. Anticholinesterase activity suggests the potential ability of the new compounds to block β-amyloid aggregation induced by anticholinesterase, making them promising candidates for further research preparations for the treatment of Alzheimer's disease. Particular attention should be paid to the conjugate with an intertriazol hexamethylene spacer, which can be regarded as the leading compound in this series.
Diversity of hairpin-like defense peptides from barnyard grass (Echinochloa crusgalli L.) seeds
Abstract
The results of structural and functional analyses of harpin-like peptides from the EcAMP group isolated from the barnyard grass (E. crusgalli) seeds are summarized from the viewpoint of their participation in plant innate immunity to environmental biotic stress factors.
Recombinant production and structure-function study of ts1 toxin from the Brazilian scorpion Tityus serrulatus
Abstract
This work introduces an effective bacterial system for the production of β-toxin Ts1, the main component of the Brazilian scorpion Tityus serrulatus venom. Recombinant toxin and its 15N-labeled analogue are obtained by direct expression of the synthetic gene in Escherichia coli, with subsequent folding from the inclusion bodies. NMR spectroscopy data assert that the recombinant toxin is structured in aqueous solution and is composed of a significant fraction of β-structure. Moreover, the formation of a stable Ts1 disulfide-bond isomer of a disordered structure is observed during folding; recombinant Ts1 blocks Na+ current through NaV1.5 channels, without affecting the processes of activation and inactivation. Simultaneously, the effect upon NaV1.4 channels is associated with a shift of the activation curve toward the more negative membrane potentials.
Physiology
Effect of taste receptor protein T1R3 on the development of islet tissue of the murine pancreas
Abstract
Protein T1R3, the main subunit of sweet, as well as amino acid, taste receptor, is expressed in the epithelium of the tongue and gastro intestinal tract, in β–cells of the pancreas, hypothalamus, and numerous other organs. Recently, convincing witnesses of T1R3 involvement in control of carbohydrate and lipid metabolism, and control of production of incretines and insulin, have been determined. In the study on Tas1r3-gene knockout mouse strain and parent strain C57Bl/6J as control, priority data concerning the effect of T1R3 on the morphological characteristics of Langerhans islets in the pancreas, are obtained. In Tas1r3 knockout animals, it is found that the size of the islets and their density in pancreatic tissue are reduced, as compared to the parent strain. Additionally, a decrease of expression of active caspase-3 in islets of gene-knockouts is demonstrated. The obtained data show that the lack of a functional, gene encoding sweet-taste receptor protein causes a dystrophy of the islet tissue and associates to the development of pathological changes in the pancreas specific to type-2 diabetes and obesity in humans.
General biology
Detection of endogenous phthalates in bacterial pathogens of plants and animals
Abstract
The endogenous esters of ortho-phthalic acid, dibutil phthalate (DBP) and di-(2-ethylhexil)-o-phthalate (DEHP), have been first detected in bacterial pathogens of plants (Clavibacter michiganensis ssp. sepedonicus, Pectobacterium carotovorum ssp. carotovorum, Rhizobium rhizogenes, Rhizobium radiobacter) and animals (Escherichia coli).