bluuebunny/crossref_metadata_2025 huggingface dataset:
Peculiarities of Modified Ceramics (Na0.5Bi0.5)TiO3–BaTiO3–(K0.5Na0.5)NbO3
Authors: Kaleva G. M. , Politova E. D. , Mosunov A. V. , Ilina T. S. , Kiselev D. A.
Published: April 2024

Single-phase ceramic samples with new compositions (1 – x – у)(Na0.5Bi0.5)TiO3–хBaTiO3–у(K0.5Na0.5)NbO3 (x = 0.05, у = 0–0.15) modified with ZnO and GeO2 additions were obtained by solid-phase synthesis. Their crystal structure, microstructure, and dielectric and local piezoelectric properties were studied. A phase with a perovskite structure with a pseudocubic unit cell was found to form in all of the synthesized samples; it was shown that the unit cell volume increased as a result of the partial replacement of base cations by complex additive cations. The ferroelectric phase transitions were confirmed by dielectric spectroscopy. Residual piezoelectric hysteresis loops were obtained for the synthesized samples in the polarization switching spectroscopy mode, which confirmed the switching of ferroelectric polarization.
Equation of State of an Infinitely Dilute Solution of Argon in Water
Authors: Novikov A. A.
Published: April 2024

A new equation of state is proposed for a solution of gas at infinite dilution, based on considering the interaction between a gas and a solvent at the microscopic level. It is used to describe the properties of an infinitely dilute aqueous solution of argon in a wide range of temperatures and pressures, including the supercritical region of water. It is shown that the resulting equation is capable of predicting the properties of an aqueous solution of an inert gas with high accuracy, based on a limited set of data at moderate temperatures.
Features of the Dependence of the Retention Indices of Sorbates in Reversed-Phase High-Performance Liquid Chromatography on the Content of Organic Solvents in the Eluent
Authors: Zenkevich I. G. , Deruish A. , Nikitina D. A.
Published: April 2024

Characterizing the dependence of the retention indices (RIs) of sorbates of different chemical origins on the content (С) of organic solvents (methanol, acetonitrile) in eluents used in reversed-phase HPLC shows that the coefficients dRI/dC of the same compounds for eluents of different compositions differ considerably. The range of variations in coefficients dRI/dC for water–methanol eluents (–5.6 to +4.6) is approximately twice that of water–acetonitrile eluents (−4.5 to +0.8). It is also found that for nonpolar compounds when using water–acetonitrile eluents, the dRI/dC values are typically lower than those for water–methanol eluents. The opposite is observed for polar compounds. The signs and absolute values of coefficients dRI/dC are largely determined by the polarity of the sorbates. dRI/dC 0 for nonpolar sorbates, and dRI/dC 0 for sorbates of higher polarity. Determination even of the sign of this coefficient therefore provides important information about the chemical nature of sorbates. It is shown that coefficients dRI/dC do not correlate with either the RI values or hydrophobicity logPlog⁡. However, they do correlate with homologous increments of hydrophobicity ilogP and the homologous increments of RI iRI for eluents of any composition. Quantities ilogP and iRI characterize the polarity of homologous series of sorbates, rather than the polarity of the particular sorbates.
Evolution of the Impurity Sites and Electronic Spectra of Aluminum Phthalocyanine in a Silicate Nanoreactor
Authors: Arabei S. M. , Stanishevsky I. V, , Pavich T. A. , Slonskaya S. V.
Published: April 2024

The evolution of the electronic absorption spectra of substituted aluminum phthalocyanine incorporated into a nanoporous silicate gel matrix has been studied. The decomposition of the contour of the long-wavelength Q-absorption band of molecules into Voigt components reveals the dependence of the formation of various types of impurity sites in the matrix nanopores, which act as a solid-state nanoreactor, on the drying time of the matrix. Possible mechanisms of the effect of the internal structure of the synthesized silicate material during the transition from a sol state to a dried xerogel state on the spectral properties of phthalocyanine impurity molecules are discussed. Models of the interaction of the impurity molecules with the surface of the matrix nanopores during drying are considered; the features of the evolution of the resulting impurity sites are elucidated.
Comparative Studies of Selenium Nanoparticles Stabilized with Polyelectrolytes of Different Signs
Authors: Valueva S. V. , Vylegzhanina M. E. , Bezrukova M. A. , Mitusova K. A. , Borovikova L. N. , Kutin A. A. , Gavrilova I. I. , Zolotova Yu. I. , Nazarova O. V. , Panarin E. F.
Published: April 2024

Selenium (Se0) nanoparticles are stabilized with water-soluble polymers containing ionogenic groups of the different signs, namely, poly(N,N,N-trimethylammonium)ethyl methacrylate iodide (polycation) and sodium polystyrenesulfonate (polyanion). A comprehensive comparative study of the resulting selenium-containing nanodispersions by the UV–visible spectroscopy, atomic force and transmission electron microscopy, and dynamic and electrophoretic light-scattering methods is conducted. The effect of the charge sign of the polymer stabilizer on the structural–morphological, dimensional, electrochemical, and spectral characteristics of selenium-containing nanodispersions is shown.
Mechanism for the Formation of Nanoscale Oxides in a Medium of Supercritical CO2 Fluid
Authors: Golubev D. V. , Sigov A. S. , Kolobanov A. I. , Fomichev V. V.
Published: April 2024

A possible mechanism is considered for the formation of nanoscale oxides based on titanium and aluminum isopropoxides in a medium of supercritical CO2 fluid. It is shown that because of intermolecular interactions and high pressure in the system, the supercritical fluid acquires the properties of a condensed medium, the main role of which is to restrain processes of hydrolysis. At the first stage of the hydrolysis of titanium isopropoxide, the water molecule is coordinated in the outer sphere of the central atom due to the formation of intermolecular hydrogen bonds. It is then coordinated into the inner sphere with the formation of a five-coordinate transition state and its destruction, creating a product substituted for the hydroxo group. The next steps proceed in a similar way. The described mechanism agrees with experimental findings and produces nanosized X-ray amorphous titanium oxide. (With aluminum isopropoxide, only the hydrolyzed hydroxo form can be produced.) Results suggest the production of nanosized oxides from isopropoxides in a medium of supercritical CO2 fluid is possible for transitional d-elements.
Analysis of the Restructuring of the Active Layer of UAM-50 and UAM-100 Membranes during the Ultrafiltration Separation of Surfactant Solutions
Authors: Lazarev S. I. , Golovin Yu. M. , Khorokhorina I. V. , Mikhailin M. I. , Yanovskaya E. Yu. , Polyanskii K. K.
Published: April 2024

It is established that the fractions of the characteristic intensities of OH group vibrations attributed to intramolecular H-bonds of O3–H···O5 and O2–H···O6 types and intermolecular H-bonds of O6–H···O3 type of air-dried samples are 0.12, 0.1, and 0.2 for UAM-100 membrane and 0.12, 0.1, and 0.19 for UAM-50 membrane. It is shown that the characteristic intensity of the ν(OH) absorption band grows from 9.55 to 10.3 in a working sample of the UAM-100 membrane and a drop in the symmetry index to 0.75 was explained by the oxidation of aldehyde groups at C1 pyranose ring to the carboxyl (–COOH). It is proved that the fractions of intermolecular bonds of О6–Н···О3 and intramolecular H-bonds of O3–H···O5 and O2–H···O6 are 0.15, 0.09, and 0.13 that indicates not only the structural rearrangement of the hydrogen bond system but also possibly the formation of weak hydrogen bonds between hydroxyl groups of pyranose rings and molecules of the sedimentary layer.
Surface Tension of the Planar Interface of a Vapor–Liquid System on a Two-Dimensional Square Lattice
Authors: Votyakov E. V. , Tovbin Yu. K.
Published: April 2024

In an earlier work, the authors described a theoretical approach to deriving equations for equilibrium particle distributions by means of heterogeneous cluster variation (CV) that converges to the exact solution as the basis cluster grows. In this work, they present calculations of the surface tension (ST) of the planar interface of a vapor-liquid system on a two-dimensional square lattice by means of heterogeneous CV. The transitional region of the interface is a sequence of monomolecular layers with a variable fluid density fluidа. Calculations are made for six types of clusters with different sizes inside the phases (2 × n, n = 1–4, 3 × 3, and the k1s cluster with the nearest neighbors of any central site), and for eight clusters inside the transitional region (2 × 1, 2 × 2, 2 × 3, 3 × 2, 2 × 4, 4 × 2, 3 × 3, k1s) that differ by each cluster’s orientation relative to the normal to the surface. As the clusters grow, so does the accuracy of describing indirect correlations of laterally interacting particles. The temperature dependence of the ST is calculated. A monotonically growing ST is obtained as the temperature falls, starting from zero at the critical temperature. The calculation results converge to the exact Onsager solution as the clusters grow. Differences between thermodynamic requirements and ST calculations performed with the Ising model are discussed.
Structural Causes of the Non-Newtonian Behavior of Fluid Systems
Authors: Matveenko V. N. , Kirsanov E. A.
Published: April 2024

This review considers the well-known results of rheological studies, first of all, the viscosity and flow curves of various dispersed and polymer systems. The existing explanations of the causes of non-Newtonian flow are presented. Various rheological models are described, in which a change in viscosity is associated with a change in the structure of a substance. The new structural rheological model proposed by us is a generalization of the Casson and Cross rheological models. Its scope includes various structured systems: suspensions, emulsions, polymer solutions and melts, micellar solutions, and liquid crystals. Our attention was focused on the features of the stationary shear flow of non-Newtonian systems.
Thermodynamic and High-Temperature Properties of KFe0.33W1.67O6
Authors: Shvareva A. G. , Smirnova V. M. , Smirnova N. N. , Markin A. V. , Fukina D. G. , Knyazev A. V.
Published: April 2024

This paper presents the results of a study of the KFe0.33W1.67O6 system. The compound was obtained by a solid-phase synthesis method at a temperature of 1073 K. The structural, morphological, and spectroscopic properties of KFe0.33W1.67O6 were characterized using XRD, SEM-EDS. The compound crystallizes in a cubic lattice with the space group Fd–3m (227). The obtained lattice parameter a = 10.3697 (3) Å. The phase transitions of KFe0.33W1.67O6 were determined by low-temperature and high-temperature X-ray diffraction. The temperature dependence of heat capacity of KFe0.33W1.67O6 has been measured for the first time in the range from 5 to 638 K by precision adiabatic vacuum calorimetry and differential scanning calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C∘p∘(T), enthalpy H°(T) − H°(0), entropy S°(T) − S°(0), and Gibbs function G°(T) − H°(0), for the range from T → 0 to 630 K.
Dicationic Ionic Liquids with a Linker of Ether Nature
Authors: Krasovskii V. G. , Kapustin G. I. , Glukhov L. M. , Chernikova E. A. , Kustov L. M.
Published: April 2024

Bis(trifluoromethylsulfonyl)imide dicationic ionic liquids with an ethereal linker between imidazolium cations have been synthesized. Their thermal stability has been studied, melting points, viscosity, and volatility in vacuum have been measured. The properties of the synthesized ionic liquids with ethereal linkers have been compared with the properties of ionic liquids of a similar structure, but with polymethylene linkers.
Quantum-Chemical Simulation of 13C NMR Chemical Shifts of Fullerene C60 Exo-Derivatives
Authors: Tulyabaev A. R. , Khalilov L. M.
Published: April 2024

The 13C NMR chemical shifts of fullerene C60 exo-derivatives were calculated using quantum chemical hybrid functionals combined with Pople, Dunning correlation-consistent, and def2-TZVP split valence basis sets taking into account the solvent effect (polarizable continuum model). A relationship between theoretical and experimental 13C NMR chemical shifts (CSs) is assessed quantitatively to select a functional/basis set combination. It is found that the CAM-B3LYP/6-31G and M06L/6-31G combinations have the best convergence with experimental data in modeling the 13С NMR CSs of sp3 fullerene carbon atoms in С60 derivatives, whereas X3LYP/6-31G and CAM-B3LYP/6-31G(d) in modeling the 13С NMR CSs of their sp2 fullerene carbon atoms.
Using Immobilized Hybrid Composites Based on Mixed Polyoxometalates As Catalysts for the Oxidation of Heteroatomic Compounds
Authors: Zelikman V. M. , Maslakov K. I. , Ivanin I. A. , Tarkhanova I. G.
Published: April 2024

A set of silica gel-immobilized compounds is synthesized that consists of ethylimidazole cations and anions of phosphotungstic acid (lacunar (PW11) or mixed (PW11M), where M = Zn, Ni, Cu, Co, Mn). The composition and textural characteristics of the compounds are determined by physicochemical means (IR spectroscopy, XPS, SEM/EDX, adsorption). The synthesized heterogeneous composites are active in the oxidation of sulfur- and nitrogen-containing components of petroleum feedstocks with hydrogen peroxide. A comparative analysis is performed of the samples’ catalytic properties in the oxidation of both individual substrates (thiophene, dibenzothiophene, methyl phenyl sulfide, pyridine) and their mixtures.
Structure and Kinetic Properties of a Molten FLiBe Mixture with Tritium
Authors: Galashev A. E. , Anisimov A. F. , Vorob’ev A. S.
Published: April 2024

A study is performed of the self-diffusion of tritium and fluorine atoms, and the change in the structure of molten FLiBe upon raising the temperature of the system from 873 to 1073 K. The interaction between neutrons and both lithium and beryllium in molten-salt reactors (MSR) using FLiBe as a fuel salt results in the formation of large amounts of tritium. Tritium, which easily penetrates metallic structural materials at high temperatures, is a radionuclide hazard. Predictive models for the behavior of tritium in a molten fluoride salt must therefore be developed to solve the problem of MSR safety. The emergence of tritium in the system increases the average energy of interatomic bonds upon raising the temperature and concentration of tritium in the system. A rise in temperature is also accompanied by fluorine atoms creating a closer short-range order in the environment of tritium atoms. This is expressed in the formation of a high first peak of radial distribution function gT-F(r), an increase in the number of probable geometric neighbors, which is shown by Voronoi polyhedra, and fluorine atoms giving priority to fourth-order rotational symmetry in the environment of tritium atoms.
Investigation of Physicochemical Characteristics of Lead Dioxide Coatings to Enhance the Performance of Reserve Quickly Activated Chemical Power Sources in the Lead–Perchloric Acid–Lead Dioxide System
Authors: Shcheglov P. A. , Samsonov D. A. , Pavlenkov A. B. , Kulova T. L. , Rychagov A. Yu. , Andreev V. N. , Skundin A. M.
Published: April 2024

The relationship between the discharge characteristics of reserve chemical power sources of the lead–perchloric acid–lead dioxide system and the physicochemical properties of electroplated cathode coatings with lead dioxide, including phase composition and microstructure, has been studied. The study reveals that the discharge characteristics of power sources can be enhanced by employing a two-layer lead dioxide coating consisting of a porous outer layer and a denser inner layer. The findings have been validated through the production and testing of industrial prototypes of pilot miniature reserve power sources, which exhibit improved performance even at low temperatures (activation time, less than 30 ms; discharge capacity, ~200 mA min/cm2; discharge voltage per cell, 1.8–1.2 V at –50°C).
INVESTIGATION OF DIFFERENCE SCHEMES FOR TWO-DIMENSIONAL NAVIER-STOKES EQUATIONS BY USING COMPUTER ALGEBRA ALGORITHMS
Authors: BLINKOV Yu. A. , REBRINA A. Yu.
Published: April 2024

A class of consistent difference schemes for incompressible Navier–Stokes equations in physical variables and their differential approximations are considered using an algorithm for Gröbner basis construction. Results of investigating the first differential approximations of these schemes, which are obtained by using the authors' programs implemented in the SymPy computer algebra system, are presented. For the difference schemes under consideration, the quadratic dependence of the error for large Reynolds numbers and the inversely proportional dependence for creeping currents are analyzed.
IMPLEMENTATION OF GEOMETRIC ALGEBRA IN COMPUTER ALGEBRA SYSTEMS
Authors: GEVORKYAN M. N. , KOROL'KOVA A. V. , KULYABOV D. S. , DEMIDOVA A. V. , Velieva T. R.
Published: April 2024

For describing specialized mathematical structures, it is preferable to use a special formalism rather than a general one. However, tradition often prevails in this case. For example, to describe rotations in the three-dimensional space or to describe motion in the Galilean or Minkowski spaces, vector (or tensor) formalism, rather than more specialized formalisms of Clifford algebra representations, is often used. This approach is historically justified. The application of specialized formalisms, such as spinors or quaternions, has not become a mainstream in science, but it has taken its place in solving practical and engineering problems. It should also be noted that all operations in theoretical problems are carried out precisely with symbolic data, and manipulations with multidimensional geometric objects require a large number of operations with the same objects. And it is in such problems that computer algebra is most powerful. In this paper, we want to draw attention to one of these specialized formalisms—the formalism of geometric algebra. Namely, it is proposed to consider options for the implementation of geometric algebra in the framework of the symboliccomputation paradigm.
REAL-TIME ANALYTICS: BENEFITS, LIMITATIONS, AND TRADEOFFS
Authors: KUZNETSOV S. D. , VELIKHOV P. E. , Fu Q.
Published: April 2024

Real-time analytics is a relatively new branch of analytics. A common definition of real-time analytics is that it consists in analyzing data as quickly as possible over the most recent data possible. This defines the essence of the fundamental needs of users, but in no way is a specific requirement for the corresponding software systems due to the vagueness of the definition. As a result, different manufacturers of analytical datamanagement systems and researchers classify real-time analytics systems as extremely different systems, which differ in architecture, functionality, and even timing. The purpose of this article is to analyze the different approaches to providing real-time analytics, their advantages and disadvantages, and the tradeoffs that both system designers and their users inevitably have to make.
ALGORITHM FOR COMPUTING THE TRUNCATION OF THE DISCRIMINANT OF A POLINOMIAL
Authors: LYAPIN A. P. , MIKHALKIN E. N.
Published: April 2024

A program that computes the truncation of the discriminant for a polynomial of one variable onto facets of the Newton polytope for the discriminant of this polynomial, as well as enables the factorization of this truncation into the product of discriminants of polynomials of lower degrees, is developed.
USING DYNAMIC MEMORY REALLOCATION IN GINV
Authors: BLINKOV Yu. A. , SHCHETININ E. Yu.
Published: April 2024

A new version of GInv (Gröbner Involutive) for computing involutive Gröbner bases is presented as a library in C++11. GInv uses object-oriented memory reallocation for dynamic data structures, such as lists, red-black trees, binary trees, and GMP libraries for arbitrary-precision integer calculations. The interface of the package is designed as a Python3 module.
DEVELOPMENT OF ALGORITHMS AND SOFTWARE FOR MODELING CONTROLLED DYMAMIC SYSTEMS USING SYMBOLIC COMPUTATIONS AND STOCHASTIC METHODS
Authors: DEMIDOVA A. V. , DRUZHININA O. V. , MASINA O. N. , PETROV A. A.
Published: April 2024

The development of software for synthesizing and analyzing models of controlled systems taking into account their deterministic and stochastic description is an important direction of research. Results of the development of software for modeling dynamic systems the behavior of which can be described by onestep processes are presented. Models of population dynamics are considered as an example. The software uses a deterministic description of the model at its input to obtain a corresponding stochastic model in symbolic form and also analyze the model in detail (calculate trajectories in the deterministic and stochastic cases, find control functions, and visualize the results). An important aspect of the development is the use of computer algebra for analyzing the model and synthesizing controls. Methods and algorithms based on deterministic and stochastic Runge–Kutta methods, stability and control theory, methods for designing self-consistent stochastic models, numerical optimization algorithms, and artificial intelligence are implemented. The software was developed using high-level programming languages Python and Julia. As the basic tools, high-performance libraries for vector–matrix computations, symbolic computation libraries, libraries for the numerical solution of ordinary differential equations, and libraries of global optimization algorithms are used.
Effective Lower Bounds on the Matrix Rank and Their Applications
Authors: Zverkov O. A. , Seliverstov A. V.
Published: April 2024

We propose an efficiently verifiable lower bound on the rank of a sparse fully indecomposable square matrix that contains two non-zero entries in each row and each column. The rank of this matrix is equal to its order or differs from it by one. Bases of a special type are constructed in the spaces of quadratic forms in a fixed number of variables. The existence of these bases allows us to substantiate a heuristic algorithm for recognizing whether a given affine subspace passes through a vertex of a multidimensional unit cube. In the worst case, the algorithm may output a computation denial warning; however, for the general subspace of sufficiently small dimension, it correctly rejects the input. The algorithm is implemented in Python. The running time of its implementation is estimated in the process of testing.
SCENARIO OF INFORMATION FLOW ANALYSIS IMPLEMENTATION IN PL/SQL PROGRAM UNITS WITH PLIF PLATFORM
Authors: TIMAKOV A. A.
Published: April 2024

Formal proof of security measure effectiveness and computation security is vitally important for trust in critical information systems. It should be realized that formal security verification must be carried out at each infrastructural level (from the hardware level to the application level) in the process of system design. Currently, computation security analysis on the application level remains the major challenge as it requires complex labeling of computing environment elements. Traditionally, to solve this problem, information flow control (IFC) methods are employed. Unlike access control mechanisms widely used in modern operating systems (OSs) and database management systems (DBMSs), IFC has limited application in software design and mostly comes down to trivial taint tracking. This paper describes an approach to full-fledged implementation of IFC in PL/SQL program units with the use of the PLIF platform. In addition, a general scheme of computation security analysis for enterprise applications that work with relational DBMSs is considered. The key advantage of our approach is the explicit separation of functions between software developers and security analysts.
GRADIENT-FREE ALGORITHMS FOR SOLVING STOCHASTIC SADDLE OPTIMIZATION PROBLEMS WITH THE POLYAK–LOYASIEVICH CONDITION
Authors: Sadykov S. I. , Lobanov A. V. , Raigorodskii A. M.
Published: April 2024

This paper focuses on solving a subclass of a stochastic nonconvex-concave black box optimization problem with a saddle point that satisfies the Polyak–Loyasievich condition. To solve such a problem, we provide the first, to our knowledge, gradient-free algorithm, the approach to which is based on applying a gradient approximation (kernel approximation) to the oracle-shifted stochastic gradient descent algorithm. We present theoretical estimates that guarantee a global linear rate of convergence to the desired accuracy. We check the theoretical results on a model example, comparing with an algorithm using Gaussian approximation.
Monoclonal Line of Cells Co-Expressing Genetically Encoded Sensors of cAMP and Ca2+
Authors: Kotova P. D. , Rogachevskaja O. A. , Kolesnikov S. S.
Published: April 2024

A variety of surface receptors and intracellular signaling systems are involved in cell-to-cell communication and paracrine/autocrine regulation of cellular functions. Being most numerous, the family of G-protein coupled receptors (GPCRs) is involved in the regulation of almost all physiological processes due to coupling to multiple and diverse intracellular signaling cascades. Among them, the ubiquitous players are the adenylate cyclase cascade, which controls the intracellular cAMP level, and the phosphoinositide cascade, which determines many aspects of intracellular Ca2+ signaling. Certain facts suggest that the adenylate cyclase and phosphoinositide cascades can be cross regulated. It therefore can be expected that agonists of adenylate cyclase-coupled GPCR receptors also might affect intracellular Ca2+, and in turn, Ca2+-mobilizing ligands might initiate a change in the cAMP level. Thus, simultaneous monitoring of cAMP and Ca2+ in the cell cytosol appears to be rational, as it can significantly refine the understanding of signaling processes initiated by agonists. The on-line monitoring of intracellular cAMP is currently possible only with the use of genetically encoded sensors; such sensors have also been developed for the analysis of intracellular Ca2+ signals. Here we generated a monoclonal line HEK-293 co-expressing molecular fluorescent sensors for cAMP (Pink Flamindo) and Ca2+ (GEM-GECO1). Physiological tests showed that this cell line provides the possibility of simultaneous monitoring of cAMP and Ca2+ with sufficient sensitivity. Such a tool can increase the efficacy of studying agonist-induced intracellular processes and, in particular, the analysis of crosstalk between the cAMP and Ca2+ signaling systems.
Benzimidazole Derivative NS1619 Inhibits Functioning of Mitochondria Isolated from Mouse Skeletal Muscle
Authors: Dubinin M. V. , Igoshkina A. D. , Semenova A. A. , Mikina N. V. , Khoroshavina E. I. , Belosludtsev K. N.
Published: April 2024

The activator of the large-conductance Ca2+-activated K+ channel (BKCa) NS1619 is known to have a pleiotropic action and is able to affect the functioning of other transport systems of the cell and its organelles. In this work, we have studied the effect of this benzimidazole derivative on the functioning of isolated mouse skeletal muscle mitochondria. NS1619 has been shown to dose-dependently inhibit respiration and oxidative phosphorylation of mouse skeletal muscle mitochondria fueled by glutamate/malate (complex I substrates) or succinate (complex II substrate). This action of NS1619 is based on the inhibition of the activity of complexes I, III, and IV of the respiratory chain of organelles, as well as ATP synthase and is accompanied by a dose-dependent decrease in the membrane potential of organelles fueled by the above substrates or ATP. In addition, NS1619 significantly reduces the ability of mitochondria to uptake and retain calcium ions in the matrix. At the same time, we noted the antioxidant effect of NS1619 expressed in a decrease in the production of hydrogen peroxide by skeletal muscle mitochondria fueled by glutamate and malate. The mechanisms of the possible toxic effects of NS1619 on skeletal muscle mitochondrial function and its contribution to the side effects observed in the treatment of muscle pathologies in vivo are discussed.
BAR Domain Proteins As Putative Regulators of the Protein Liquid Phase in Nerve Terminals in the Central Nervous System
Authors: Shishkov A. G. , Nifantova N. V. , Korenkova O. M. , Sopova E. S. , Brodin L. , Shupliakov O.
Published: April 2024

BAR proteins are key components of the synaptic vesicle cycle in nerve terminals. They participate in the regulation of neurotransmitter release during the fusion of synaptic vesicles with the presynaptic membrane and synaptic vesicle recycling. Localization of these proteins at sites of liquid–liquid phase separation in nerve terminals suggests additional functions of these molecules. In the current review, we discuss the tasks of BAR proteins at different stages of the secretory cycle, including their putative role in liquid–liquid phase transitions in nerve terminals during synaptic activity. We suggest that BAR proteins, along with their established functions in exo- and endocytosis, play crucial roles in the organization of the reserve pool of synaptic vesicles and at the intermediate stages of the vesicle cycle.
Force Characteristics of Yersinia pestis Lipopolysaccharide Interaction with TLR4 and CD14 Receptors on J774 Macrophages. Atomic Force Microscopy
Authors: Belozerov V. S. , Ananchenko B. A. , Konyshev I. V. , Dudina L. G. , Konnova S. A. , Rozhina E. V. , Fakhrullin R. F. , Byvalov A. A.
Published: April 2024

One of the main stages of infectious process, which mostly determines the course and outcome of the disease, is the initial contact of the pathogen with the host cells. The lipopolysaccharide as a component of the outer membrane is crucially involved in the interaction between Gram-negative bacteria and immunocompetent host cells. It triggers immune reactions by interaction with specific receptors, mainly CD14 and TLR4. The aim of this work was to quantify the force characteristics of the interaction of Yersinia pestis EV lipopolysaccharide with CD14 and TLR4 receptors on the surface of mouse macrophages J774 by atomic force microscopy. Lipopolysaccharide was extracted from Y. pestis cells (vaccine strain EV) grown at 27°С. The expression of receptors on the cell surface was evaluated by fluorescent and confocal microscopy. Using monoclonal antibodies against CD14 and TLR4 receptors, force spectroscopy was used to estimate the force characteristics of the interaction between lipopolysaccharide on the cantilever surface and J774 macrophages immobilized on a glass substrate. The conditions for immobilization of J774 macrophages on glass were developed that allowed scanning the cell surface and estimating the adhesion force of target antigens to the cells. Incubation of macrophages in solutions with monoclonal antibodies against CD14 and TLR4 receptors caused a decrease in the major force characteristics of the interaction in the J774 macrophage – Y. pestis lipopolysaccharide system compared to the system containing untreated macrophages. A similar effect was observed after pretreatment of the cells with a solution containing the same lipopolysaccharide without monoclonal antibodies. The results show the ability of the Y. pestis lipopolysaccharide chemically bound to the cantilever to interact with CD14 and TLR4 receptors on the macrophage surface.
Membrane-Active Mitochondria-Targeted Antitumor Agents and Drug Delivery Systems
Authors: Sadikov A. P. , Denieva Z. G. , Budanova U. A. , Sebyakin Yu. L.
Published: April 2024

Mitochondria are “power stations” of cells. Without them the normal functioning of a living cell is impossible. This organelle is an attractive target for antitumor therapy because of the variety of processes in which mitochondria are involved and the differences between mitochondria in healthy and tumor cells. In this review, various approaches to the development of diagnostic and therapeutic agents selectively directed to the mitochondria of tumor cells are described. The main mitochondrial vector ligands, their conjugation with known antitumor drugs, as well as their combination with common drug delivery systems are described.
Role of Nitric Oxide and Hydrogen Sulfide in Neuronal and Glial Cell Death in Neurodegenerative Processes
Authors: Rodkin S. V. , Nwosu C. D.
Published: April 2024

Neurodegeneration is a complex progressive pathological process leading to the neuronal death, which is induced by various external and internal factors. Neurodegenerative diseases, injuries of the central and peripheral nervous system, mental disorders, and a number of other pathological conditions, accompanied by functional and structural degradation of neurons and their death, is a serious problem in the global healthcare system, as due to these diseases millions of people around the world become disabled or die every year. The situation is complicated by the lack of selective, clinically effective neuroprotective drugs. It has been shown that nitric oxide (NO) and hydrogen sulfide (H2S) are actively involved in neurodegeneration and cell death of neurons and glia, but their role is not completely clear. This review considers NO- and H2S-dependent signaling mechanisms underlying the pathogenesis of neurodegenerative processes. The prospects for further studies of the role of NO and H2S in the nervous tissue under conditions of pathological conditions associated with neurodegeneration are considered.
Analysis of the Role of Piezo1 Channels in Mechano-Anabolic Coupling in Rat Soleus Muscle
Authors: Mirzoev T. M. , Sergeeva K. V. , Tyganov S. A. , Kalashnikov V. E. , Shenkman B. S.
Published: April 2024

It is known that mTORC1-dependent pathway is involved in the activation of muscle protein synthesis and hypertrophy in response to mechanical stress. However, mechanosensors that mediate sensing and transmission of mechanical signals to the mTORC1 signaling pathway (mechanotransduction) are not yet identified. Mechanically activated (MA) ion channels are viewed as potential candidates for the role of such sarcolemmal mechanosensors. The aim of our work was to investigate the potential role of MA channels (Piezo1) in the activation of the mTORC1 pathway in the isolated rat soleus muscle in response to mechanical stress. Wistar rats were divided into 3 groups: 1) “Control” (isolated muscles were not exposed to MA channel inhibitor or Piezo1 channel activator); 2) “Gadolinium” (muscles were incubated with MA channel inhibitor, gadolinium chloride); 3) “Yoda” (muscles were incubated with Yoda1, Piezo1 activator). In rats from each group, the soleus from the left limb was incubated in the appropriate solution without mechanical stress in the form of a passive stretching, and the soleus from the right limb was subjected to passive stretching and then incubated in the appropriate solution. Phosphorylation of mTORC1 targets (p70S6K, rpS6, 4E-BP1) in rat soleus was determined by PAGE and immunoblotting. After passive stretching of the isolated soleus muscle there was an increase in phosphorylation of p70S6K, its substrate, rpS6, as well as 4E-BP1, by 38.5%, 168%, and 112%, respectively, compared to the soleus muscle that was not subjected to stretching. Incubation of the muscles with gadolinium completely prevented the activation of mTORC1 markers caused by stretching. Incubation of the soleus muscle in the solution with Yoda1 resulted in a decrease in the mechano-dependent phosphorylation of p70S6K, rpS6, and 4E-BP1 compared to a muscle that was not exposed to Yoda1. Thus, Piezo1 channels do not appear to play a role in the activation of mTORC1 signaling in rat soleus muscle in response to passive stretching.
Modern Trends of the Application of Stem Cells and Their Derivatives during Cryopreservation of Animal Sperm
Authors: Tambovsky M. A. , Aimaletdinov А. М. , Zakirova E. Yu.
Published: April 2024

Cryopreservation is an important method for preserving sperm from various organisms. However, freezing gametes often leads to various types of cell damage, which affects the outcome of artificial insemination. After thawing, spermatozoa usually have ultrastructural, biochemical and functional changes such as cell membrane and chromatin damage and oxidative stress. Since spermatozoa have limited biosynthetic capacity, they have a low capacity to regenerate. The current trend is to improve the sperm cryopreservation regime using natural extracellular vesicles and stem cells. Extracellular vesicles and stem cells have a potential regenerative effect, as they contain various biologically active molecules affecting sperm repair. This review focuses on current strategies to improve sperm health after cryopreservation. In particular, this review describes the results of studies on the use of extracellular vesicles and stem cells as cryoprotectors during freezing and thawing of spermatozoa.
The Study of the Mechanism of Gamma-Aminobutyric Acid Inhibitory Effect on the Myotube Formation Process in Cell Culture
Authors: Tokmakova A. R. , Sibgatullina G. V. , Gilizhdinova K. R. , Malomouzh A. I.
Published: April 2024

Gamma-aminobutyric acid (GABA) is commonly regarded as a signaling molecule in CNS synapses, where it plays the role of the main inhibitory neurotransmitter in the mature brain and is involved in the process of neurogenesis. Recently, data have been obtained indicating that GABA can also be involved in the early stages of the skeletal muscle development process. In the present study performed on rat cultured myocytes, we a-nalyzed the effect of exogenous GABA on the process of myocyte fusion into myotubes as assessed by the morphometric parameter “fusion index”. Addition of GABA to the cell culture resulted in a significant concentration-dependent inhibition, up to complete cessation, of myotube formation. Of possible proteins that can mediate this effect, GABAA receptors and GABA transporters (GAT-2) have been considered. Evidence of the presence of these proteins on cultured cells was obtained by immunohistochemistry methods. The blockade of GABAA receptors by gabazine had no effect on the fusion index, and GABA exerted its inhibitory effect in the presence of gabazine. Inhibition of GABA transporters by nipecotic acid, in itself, reduced the myocyte fusion index; however, there was no effect of GABA in the presence of this blocker of GABA transporters. The data obtained are consistent with the hypothesis about the participation of GABA in the early stages of skeletal muscle development. Results suggest that the inhibitory effect of exogenous GABA may be due to an increase in its concentration in the sarcoplasm, since both the addition of a GABA transporter inhibitor and an increase in the extracellular concentration of GABA inhibited the formation of myotubes.
Immunofluorescent Identification of GABAergic Structures in the Somatic Muscle of the Earthworm Lumbricus terrestris
Authors: Nurullin L. F. , Almazov N. D. , Volkov E. M.
Published: April 2024

Using the immunofluorescence confocal microscopy, we detected the following GABAergic structures in the somatic muscle of the body wall of the earthworm: neurotransmitter gamma-aminobutyric acid (GABA); the enzyme responsible for synthesis of GABA, glutamate decarboxylase; type 1, 2, and 3 membrane transporters of GABA providing its reuptake; pre- and postsynaptic type A (ionotropic) and type B (metabotropic) GABA receptors. These structures are localized in the areas of cholinergic neuromuscular synapses. We assume that GABA can participate in modulation of motor activity of the earthworm somatic muscles both at pre- and postsynaptic levels of cholinergic neuromuscular synapses.
ON THE MECHANISM OF INTERMETALLIC FORMATION DURING CATHODIC CO-REDUCTION OF IONS IN MOLTEN SALTS
Authors: Krotov V. E. , Zaikov Yu. P.
Published: April 2024

Two mechanisms of electrolytic synthesis of intermetallic (IMs) during the simultaneous reduction (co-reduction) of their ions at the cathode in salt melts are known. And both are wrong. One of them is in contradiction with the experimental data. He violates also the thermodynamics law. Another does not represent a co-reduction process, since the ions of both metals must be simultaneously reduced at the cathode and not just one some of them. The present work does not contain new experimental data, she is purely theoretical. The mechanism of the co-reduction process is proposed and thermodynamically substantiated. It is shown for the first time that the first IM crystals appear not on the surface of an electropositive metal. They appear on the surface of a binary homogeneous solid solution consisting of IM components and which is formed at the initial moment of electrolysis. It has been shown and reconfirmed thermodynamically that electronegative metal ions are reduced with depolarization For the first time, the electrochemical equations for the crystallization of a phase of constant composition during long-term electrolysis, as well electrochemical equations as for crystallization of other intermetallic phases on the surface of the previous ones are presented. The presence of several IM phases in the cathode deposits obtained during long-term electrolysis under galvanostatic conditions is explained for the first time. The IMs electrocrystallization mechanism is examined for the cases of galvanostatic and potentiostatic electrolysis modes, as well as for cyclic and square wave voltammetry. It is also applicable to the co-reduction process of crystallization of metal compounds with non-metals.
MODELING OF DIRECTIONAL SOLIDIFICATION/MELTING BY THE ENTHALPY-POROSITY METHOD
Authors: Pavlyuk E. V. , Alexandrov D. V. , Kropotin N. V. , Toropova L. V. , Starodumov I. O.
Published: April 2024

The research is focused on the development of mathematical models and software based on them to simulate complex processes of structural-phase transformations for new-generation materials, such as materials with phase transitions (PCM), biomedical materials, materials for additive manufacturing, and materials for the space industry. The mathematical description of the enthalpy-porosity model is performed in this work. The equations of viscous fluid hydrodynamics are used to describe fluid motion in time and space. The analysis of necessary restrictions and assumptions in the model related to consideration of laminar flows and Newtonian fluid model is performed. The computational problem is formulated in terms of the finite volume method and the computational domain and hydrodynamic equations are discretized. The OpenFOAM software, an open integrated platform for numerical simulation of continuum mechanics problems, was used for the computations. The computational algorithm OpenFOAM was developed to analyze the physical state of the system taking into account the initial and boundary conditions in the case of conductive and convective heat transfer. The simulations of gallium melting are performed and the model is verified for the conductive and convective cases. It is shown that in the conductive case the material melting occurs uniformly along the heat sources, while different velocities of convection flows have a significant influence on the formation of the melting boundary. The mathematical models developed in the study, as well as the analytical dependences and the computer simulations are applied to describe real experimental data on crystal growth in supersaturated solutions and supercooled melts.
INTERFACE IN IMMISCIBLE IONIC MELTS
Authors: Stepanov V. P.
Published: April 2024

The results of the study of the interface properties for immiscible mixtures LiF + KBr, LiF + CsCl, LiF + RbBr, LiF + KI, LiF + CsBr, LiF + RbI, LiF + CsI, LiCl + AgBr, LiCl + AgI и NaCl+AgI are summarized. It is established that the thickness of the interface increases when the temperature grows, tending to infinity near the critical mixing temperature. At equal temperature and the ratio of ion sizes, the layer thickness for melts containing silver halides turned out to be less than in mixtures of alkali metal halides. The surface energy for mixtures of alkali metal halides decreases as the temperature increases, obeying a power equation with a critical exponent equal to 1.5 in the vicinity of the critical mixing temperature. The critical exponent for the galvanic potential for mixtures containing silver halide turned out to be 18% less than the critical exponent for interfacial tension, which is due to the peculiarities of the chemical bond of silver halides. It is shown that at the same temperature, an increase in the size difference of the mixed ions leads to an increase in the energy and a decrease in the diffusivity of the transition layer due to a decrease in the mutual solubility of the components in this direction.
SPECTRAL ANALYSIS IN THE EVALUATION OF THE ELECTROCHEMICAL BEHAVIOR OF HIGH-ENTROPY GdTbDyHoSc AND GdTbDyHoY ALLOYS
Authors: Skrylnik M. Yu. , Zaitceva P. V. , Shunyaev K. Yu. , Rempel A. A.
Published: April 2024

The corrosion behavior of disordered systems, such as high-entropy alloys, exhibit a stochastic random process. To accurately predict and analyze the behavior of these systems in service environments, it is necessary to employ new computational and experimental methods alongside classical electrochemical methods. In this study, we highlighted the effectiveness of using fast Fourier transform and wavelet analysis to assess the corrosion behavior of stochastic systems, using the example of equimolar rare-earth alloys GdTbDyHoSc and GdTbDyHoY. To evaluate the corrosion behavior, we measured the time series of potential fluctuations for the studied samples in a 0.01 M NaCl solution over a 12-hour period, at current densities ranging from 0.2 to 0.5 mA/cm2. Applying the fast Fourier transform method to analyze the obtained time series, we observed that the angular coefficient of the slope of the logarithm of the power spectral density logarithm to the logarithm of frequency increased with higher current density. Specifically, for the GdTbDyHoSc alloy, the coefficient increased from –1.46 to –1.35, indicating the prevalence of general corrosion dissolution. In contrast, for the GdTbDyHoY alloy, the coefficient increased from –1.93 to –1.77, suggesting the dominance of localized dissolution. Furthermore, we utilized wavelet analysis to process the time series data for both alloys at current densities ranging from 0.2 to 0.5 mA/cm2. This analysis allowed us to plot time series scalograms, which visually illustrated the intensity of the corrosion process on the surface of the investigated alloys. From the scalograms, we calculated the values of the global energy spectra distributed over frequency ranges, as well as the values of the total energy of the investigated systems. Interestingly, the GdTbDyHoY alloy exhibited higher total energy values compared to the GdTbDyHoSc alloy. Specifically, the total energy for the GdTbDyHoY alloy increased from 0.97 to 2.03 kV2 as the current density increased from 0.2 to 0.5 mA/cm2, respectively. For the GdTbDyHoSc alloy, the total energy increased from 0.50 to 0.84 kV2. In conclusion, the application of fast Fourier transform and wavelet analysis methods proved to be effective tools for gaining a deep understanding of the corrosion behavior of locally disordered chemical systems, such as the high-entropy alloys of GdTbDyHoSc and GdTbDyHoY composition.
Visualization of the Design Parameters of Worm Gears
Authors: Man’shin Yu. P. , Man’shina E. Yu.
Published: April 2024

Methods for graphical representation of the connection between the initial data and the main results of the design of worm gears are considered. Graphs have been developed that visualize the initial data, the resulting dimensions, and the sliding speeds in a wide range of gear ratios. Working with summary graphs prevents errors and significantly reduces the time for selecting transmission parameters in accordance with the performance criteria.