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For fifty years, scientists from different countries in different regions of the Earth, using direct and indirect methods, discovered the migration of crustal deformation and earthquakes, and revealed its wave nature, and therefore proved the reality of the existence of slow strain waves in the Earth. This review presents a brief history of the development of the concept of strain waves in the Earth, the observation methods and properties of strain waves, and main types of the geological structures generating these waves, as well as the most prominent results of the theoretical, laboratory, and in-situ observations of slow strain migration. [ABSTRACT FROM AUTHOR]

The Lower Cretaceous bryozoan assemblage in the environs of Gunib village in Dagestan is described for the first time. The studied section is located in the zone of development of the Gapshima Formation (Hauterivian) deposits. The bryozoan assemblage is characterized by high taxonomic diversity and includes 32 taxa from four suborders of order Cyclostomata: Tubuliporina (24 taxa), Cancellata (1 taxon), Articulina (1 taxon), and Cerioporina (6 taxa). Because of the poor preservation of the colonies, most taxa are defined in open nomenclature. Therefore, the true diversity of cyclostomes in the study area is not fully recognized. The assemblage includes the taxa which are similar to bryozoans previously described from different levels from Valanginian to Barremian of Switzerland and France and, partly, from the lower Hauterivian of Germany (Mecynoecia icaunensis (d'Orbigny), Mesenteripora marginata (d'Orbigny), M. reticulata (d'Orbigny), Poriceata ardescensis Walter, Apsendesia neocomiensis d'Orbigny, Diplocava biformis (Roemer), "Heteropora" arborea Koch et Dunker, and Elea periallos Taylor). The main difference of the Gunib assemblage from the Valanginian–Hauterivian assemblage of Switzerland and France and the lower Hauterivian assemblage of Germany is the presence of bryozoans from the family Eleidae, but it differs from the Barremian assemblage of France in the absence of Cheilostomata representatives. Among the studied cyclostomes, bryozoans with vertically growing colonies predominate. Some of these bryozoans are bilateral leaf-shaped, while others had thin cylindrical branches. Reticulate and massive colonies are rare, while encrusting bryozoans, which grow over erect colonies, are quite numerous. [ABSTRACT FROM AUTHOR]

We consider the first mixed problem for the system of Vlasov–Poisson equations with a given external magnetic field in a bounded domain. This problem describes the kinetics of high-temperature plasma in controlled thermonuclear fusion plants and is considered with respect to unknown functions: electric field potential, distribution functions of positively charged ions and electrons. Additionally, we assume that the distribution functions of charged particles satisfy the condition of mirror reflection from the boundary of the domain under consideration. We prove the existence of global weak solutions of such a problem. [ABSTRACT FROM AUTHOR]

A comparative study of oxidative stress markers (ischemia-modified albumin (IMA) and the blood serum antioxidant capacity) in normal pregnancy and preeclampsia was carried out. The IMA level and blood serum antioxidant capacity increased in the following order: healthy non-pregnant women→healthy pregnant women→patients with moderate preeclampsia→patients with severe preeclampsia (p<0.001). A significant positive correlation was revealed between blood serum antioxidant capacity and uric acid levels in all the examined groups. The results showed that oxidative stress in preeclampsia is more pronounced compared to normal pregnancy. The levels of IMA and the blood serum antioxidant capacity can be additional criteria for assessment of the severity of preeclampsia and predicting of its course. [ABSTRACT FROM AUTHOR]

Nonsymmetrical lithium β-diketonate (LiL) containing tert-butyl and acetal substituents at the dicarbonyl cage has been synthesized for the first time and is structurally characterized (CIF file CCDC no. 2364039 (I)). The reactions of functional lithium β-diketonate with salts of trivalent rare-earth metals in methanol afford heterobinuclear complexes [(LnL3)(LiL)(MeOH)] (Ln = Eu, Gd, Tb). The structures of the complexes are characterized by X-ray diffraction (XRD) (CIF files CCDC nos. 2364040 (II), 2364041 (III), 2364042 (IV)). [ABSTRACT FROM AUTHOR]

Dolerite dikes were studied in the western part of the Aldan terrane, in the middle reaches of the Tokko River. These dolerite dikes form a swarm of submeridional trend about 1 km wide. The dolerites of the thickest dike preserve their primary textural and structural features and mineral composition: plagioclase + pigeonite + augite + titanomagnetite. Dolerite in the chilled margins and central parts of the dike are homogeneous in composition, corresponds to low-Mg tholeiites, has low contents of Ti and other HFSE, with weak enrichment in light REE and small negative Nb anomalies. Sm–Nd isotope data on magmatic minerals of dolerite from the central part of the dike yield a good linear regression in an isochron diagram that gives to an age of 2510 ± 64 Ma, which probably corresponds to the crystallization age of the basalt. Metadolerites in a thin dike retain plagioclase porphyritic structures, but the pyroxenes are completely replaced by amphibole and chlorite. The metadolerites are contrastingly different in low contents of MgO, Cr, and Ni and in higher contents of TiO2, Fe2O3, P2O5, Nb, and all REE. The differences in the composition of the dikes may be explained by the longterm (about 65%) crystallization differentiation of the initial melt and the emplacement of the residual melt from a shallow intermediate magma chamber via opening cracks. Such conditions probably may have existed in tectonically stable intraplate settings. The age of the dolerites of the dike swarm is comparable to that of the anorogenic granites of the Nelyuki complex (~2.4–2.5 Ga), which are widespread in the western part of Aldan granulite–gneiss terrane. Our data bridge some gaps in characteristics of intraplate anorogenic magmatism that occurred in the western Aldan Shield in the Late Archean and marked the final consolidation of a large block of Archean crust in the Chara–Olekma granite–greenstone area. [ABSTRACT FROM AUTHOR]

An approach to the synthesis of polydentate ligands in which the NH-pyrazole cycle is connected by the hydrazone group to the azine fragment (pyridine or pyrimidine) is developed. In the reactions with zinc(II) chloride, the synthesized bis(heterocyclic) compounds act as tridentate ligands with the formation of mononuclear complexes [Zn(L)Cl2] (CIF files CCDC nos. 2352630 (I) and 2352631 (II)). The absolute quantum yield (QY = 12%) and fluorescence lifetime (τ = 2.64 ns) are measured for complex II containing the pyridine cycle as the azine fragment. [ABSTRACT FROM AUTHOR]

An approach was developed for the synthesis of polyfunctionalized pyrimidines based on analogs of 1,2,4-triketones. Acetal-substituted β-diketones are involved in the condensation with amidines in the presence of an excess of (EtO)3B/Et3N in acetonitrile. The conditions of the acid hydrolysis of acetal-containing pyrimidines were found to depend on the nature of substituents in diazine. The use of 1,2,4-triketone in the condensation with amidine allows the synthesis of acetylpyrimidine in one step. [ABSTRACT FROM AUTHOR]

An optimization problem has been formulated and solved for the concurrent start of the trolleying and slewing mechanisms in a tower crane with a saddle jib. A dynamic model of the crane trolleying system with six degrees of freedom has been employed. The model incorporates the primary motion of the mechanisms as well as the oscillations of the slewing structure, trolley, and load, induced by the elastic properties of the structural components and cables. The differential equations governing the concurrent motion of the mechanisms have been derived based on the dynamic model. The optimization criterion is defined as the root-mean-square value of the total power. The generalized coordinates and velocities of the trolleying system at the start and end of the motion have been used to define the boundary conditions for the optimal motion trajectory. These coordinates are expressed in terms of the load position and its higher-order time derivatives. As a result of the optimization, the motion conditions that minimize the power of the drive mechanisms, reduce dynamic loads, and eliminate oscillations of links and load when transitioning to steady-state motion of the mechanisms have been obtained. [ABSTRACT FROM AUTHOR]

The structure dynamics in the temperature range of the melting phase transition of a dimyristoyl-phosphatidylserine multilayer on the surface of a colloidal silica solution with a particle diameter of 5 nm has been investigated by X-ray reflectometry and grazing diffraction of 71-keV photons. The joint model and model-free analysis of the reflectometry data revealed a structure consisting of a surface lipid monolayer and a set of lamellar bilayers sandwiched between water layers, with a period of ~150 Å. With an increase in temperature above the critical value one can observe a surface monolayer transition from a crystalline phase with a minimum area per lipid molecule of 40 ± 1 Å2 to a disordered (liquid) phase with a calculated area per molecule of 52 ± 2 Å2. At low temperatures, the data indicate that from five to eight H2O molecules are tightly bound to the PS fragment of the lipid in both the monolayer and the bilayer structures. However, above the transition temperature, approximately 14 water molecules are attached to the headgroups of the bilayer: this is almost twice as many molecules as the eight H2O molecules-per-headgroup in the surface monolayer. [ABSTRACT FROM AUTHOR]

The structure, phase composition, and basic mechanical and corrosion properties of powder aluminumbased composites obtained by the hot forging (HF) method were studied. The results of studies of the microstructure of synthesized master alloy of different compositions revealed the presence of particles of the strengthening phase of different dispersion and shapes, which are rather evenly distributed in the metal matrix. The method of X-ray phase analysis established the presence of titanium and aluminum carbide, and also a number of lines belonging to titanium aluminides Al3Ti , Al5Ti3 , Al2Ti , AlTi3 , Al5Ti2. Aluminium-based composite materials were strengthened with the Al–C–Ti master alloy of various compositions. Studies of the samples obtained after HF show that the microstructure of the composites is characterized by the presence of two phases: the base, and the aluminum matrix, in which the agglomerates of the master alloy are distributed. The composites alloyed with 15 mass% of the master alloy (20Al–64Ti–16C) in the initial charge and obtained by the method of sintering and HF have increased strength characteristics and demonstrate high strength and resistance properties in a 3.5% NaCl solution, regardless of the phase composition of the master alloy. [ABSTRACT FROM AUTHOR]

We theoretically study a manifestation of the Aharonov–Bohm effect in hydrodynamic instability of a tubular nonrelativistic electron beam moving along a semiconductor nanotube with dielectric filling placed in a coaxial dc magnetic field. The calculations are performed with taking into account the retardation effect for electromagnetic fields. The dispersion equation for the coupled waves of the structure under study and the electron beam, as well as the expression for the increment of the hydrodynamic instability have been derived and numerically analyzed. The mechanism of nonlinear stabilization of the hybrid bulk-surface and surface electromagnetic waves is studied by the method of slowly varying in time amplitudes and phases. The physical cause of excitation of such waves is the Cherenkov resonance, and the nonlinear stabilization mechanism is based on the trapping of beam particles by the field of the excited wave. The numerical analysis shows that the time of saturation of the instability and the maximum field amplitudes depend on the number of magnetic flux quanta in the nanotube and changes with the period equal to one magnetic flux quantum. These dependences are the result of the Aharonov–Bohm effect. [ABSTRACT FROM AUTHOR]

A nonaxisymmetric contact problem on a circular interfacial inclusion of arbitrary shape under mixed boundary conditions with a piecewise homogeneous transversely isotropic space is considered. One edge of the inclusion is in smooth contact (tangential stresses are zero), while the other is in full contact with the medium. The problem is reduced to a system of five two-dimensional singular integral equations. For the inclusion, which has an axisymmetric shape under arbitrary loads, an exact solution of the system is obtained and its asymptotic properties are determined. On the basis of the latter, an efficient numerical-analytical method for solving the system of two-dimensional singular integral equations is proposed. The stress distribution in the vicinity of a coin-shaped inclusion is obtained and its features are revealed. [ABSTRACT FROM AUTHOR]

Samples of amorphous silicon dioxide (SiO2) are obtained by acidic decomposition of mineral raw materials (nepheline). The physicochemical and structural surface properties of the samples are studied using chemical and granulometric analyses and the BET and BJH methods. It is established that the obtained SiO2 samples are almost identical to pyrogenic amorphous silicon dioxide obtained from reactive raw materials (pharmaceutical remedy Polysorb MP) in impurity content and have higher specific external surface area (by a factor of 1.1–1.9) and specific pore volume (by factor of about 1.4) compared to Polysorb MP. An economic assessment of their production cost is performed, which shows that the cost of silicon dioxide obtained by the developed technologies is more than two times lower than the cost of commercial pyrogenic silicon dioxide that is present in the market. Based on the obtained results, we discuss the prospects of using silicon dioxide obtained on the basis of acidic treatment of mineral raw materials as an enterosorbent in therapeutic practice. [ABSTRACT FROM AUTHOR]

An analysis of the changes in the carbon monoxide (CO) and particulate matter (PM10) mass concentrations in the atmosphere near highways and residential areas over Moscow during the spring lockdown in 2020 against of the mass concentrations in the previous years (2015–2019) is presented. In the lockdown period, a decrease in the CO mass concentrations was about 40% near highways and only 10% in residential areas. A decrease in the PM10 mass concentrations by about 10% was found during that period. The closeness of lockdown effects in Moscow and other megacities is shown by the comparison of trends in the traffic intensity and pollutant mass concentrations. The special importance of motor vehicles as a source of carbon monoxide emissions in the analyzed megacities is demonstrated. [ABSTRACT FROM AUTHOR]

The structural and electrical characteristics of (Mg, Zn)O ceramics produced using the solid state reaction at 1100 °C for 3 hours were studied applying X-ray diffraction and IR reflection spectroscopy as well as means of direct current measurements versus MgO content in initial charge (varied from 0 to 100 mol.%). It has been shown that electrical conductivity extracted from the IR reflection spectra corresponds to that of hexagonal phase in a solid solution, while plasmon in cubic phase was not observed. The electron concentration in the hexagonal grains of solid solution prepared with MgO content below 30 mol. % in the charge was found to be close to that of ZnO grains. It shows the tendency to decrease with further growth of the MgO content, which was explained by extraction of zinc interstitials, responsible for ZnO conductivity, from ZnO under formation of the MgZnO cubic phase. The direct current measurements have shown the lower conductivity as compared to the value estimated from IR reflection spectra. This fact along with the superlinearity of current-voltage characteristics has been explained by the presence of intergranular barriers, which does not allow obtaining information on the concentration of free electrons in the grain by this method. The possible nature of intergranular barriers as well as the role of grain boundaries in the DC conductivity of samples has been discussed. [ABSTRACT FROM AUTHOR]

An analysis of the results of multiple repeated geodetic observations of deformation processes in fault zones is presented. Numerous examples have shown that the dominant type of local vertical displacements of the earth's surface in fault zones is anomalous symmetrical subsidence, which is identified with thrust faults. A mechanism for the parametric induction of near-fault deformations by small endogenous, exogenous, and technogenic influences is proposed. Examples of these impacts are given. Antiphase behavior in the time course of deformation and seismic processes are revealed. An energy model of the relationship between deformation and seismic phenomena is considered. Based on ideas about volumetric deformations localized inside faults and formed under external (regional) quasi-static loads, a quantitative geomechanical model for the formation of anomalous deformations in fault zones has been developed. Examples of the spatiotemporal migration of deformation activity of fault zones are given. A phenomenological model of the formation of autowave deformation processes is formulated based on the mechanism of the parametric nonlinear interaction of induced faults as a system of kinematically excitable elements. [ABSTRACT FROM AUTHOR]

An analysis of the results of repeated geodynamic observations at the Buzachi peninsula field are presented. Comprehensive geodynamic monitoring includes leveling and gravimetric observations, GPS measurements, and repeated satellite radar interferometry data. A comprehensive analysis of the results shows the presence of systematic subsidence of the earth's surface in the central part of the field territory, induced by development. Based on leveling and gravimetric observations, two areas of local anomalies are identified, which are localized in zones of anomalous deformation activity of faults. Dangerous manifestations of gas gryphons have been repeatedly recorded at the field, which occurred in the area of the dynamic influence of fault zones. Deformations of the earth's surface alternating in sign (uplift and subsidence) are revealed, which precede the process of active formation of gryphons. Mathematical modeling of these processes is carried out and a generalized geomechanical model of the formation of anomalous and negative fluid dynamic manifestations is proposed. A calculation of local horizontal stresses shows that they are concentrated near active faults, forming paths for subvertical fluid migration and creating conditions for the formation of gryphons. A complex parameter is proposed to assess the level of geodynamic hazard of the field territory, and areal distribution diagrams of this parameter by year are constructed. Potentially dangerous zones of anomalous manifestation of recent deformation and fluid dynamic processes have been identified. [ABSTRACT FROM AUTHOR]

The article presents the results of a detailed spatiotemporal comparative analysis of the data obtained by platform and bottom inclinometers at the V. Filanovsky field. The slope spectra obtained by the platform inclinometers fundamentally do not coincide with the data of the bottom sensors. It turned out that platform inclinometers effectively detect exogenic deformation effects and hardly identify deformations of the seabed associated with field development processes. Using the geomechanical poroelastic inclusion model, the authors mathematically modeled the spatial distribution of the seabed slopes during a period of intensive water injection into the developed reservoir. The proposed model shows that only the system of bottom inclinometers is a geodynamic monitoring element. It is concluded that sensor systems installed only on the platforms themselves (accelerometers, inclinometers, GNSS) do not pertain to geodynamic monitoring systems (geodynamic survey areas) and cannot ensure safe and rational subsurface use. [ABSTRACT FROM AUTHOR]

The physical (phenomenological) foundations of recent geodynamics are considered. The definitions of geodynamics and recent geodynamics are substantiated based on ideas about the primacy of movements in the event of strains. The main tasks of the study are formulated, as are the scheme of formation of the recent geodynamic state of the subsoil. The issues of identifying the movements of the Earth's surface are discussed and a formula is proposed for estimating the relative bending strain. It is shown that the observed strains of the Earthʼs surface, obtained by geodetic (satellite and ground) methods, are relative in nature and depend on the specific kinematic scheme of motion of individual elements (blocks) of the medium. The results of long-term repeated geodetic observations of recent vertical and horizontal movements of the Earthʼs surface in seismically active (Kopetdag, Kamchatka) and aseismic, platform regions (Pripyat depression) are presented. It is shown that the average annual rate of regional relative strains varies in the range from 10–8 to 10–9 year–1. Zonal and local strains vary in the range from 10–4 to 10–6 year–1. The "paradoxes" of large and small strains in recent geodynamics are formulated and their explanation is given on the basis of the equations of hereditary mechanics of solids and ideas about the parametric induction of strain processes in fault zones by small natural and technogenic impacts. [ABSTRACT FROM AUTHOR]

4-Aryl-4-oxo-2-(thiophen-2-ylamino)but-2-enoates bearing a cyano functional group at the thiophene ring were synthesized by the reaction of the corresponding substituted 3-(thiophen-2-ylamino)-3H-furan-2-ones with primary alcohols. Evaluation of biological activity and acute toxicity of the synthesized esters revealed their pronounced anti-inflammatory effect and low toxicity. [ABSTRACT FROM AUTHOR]

The studies of how the method of organization of the microstructure of Pr2CuO4-based (РСО) cathodes affects the electrochemical characteristics of model electrolyte-supported solid oxide fuel cells (SOFCs) are carried out. It is shown that the higher thickness of the PCO cathode layer and the introduction of a pore-forming agent increase the power density of tested SOFCs as compared with the cathodes of the unmodified structure with the power density of 34 mW/cm2 at 850°С. The optimal thickness of the cathode layer corresponding to the maximum electrochemical performance is found to lie in the interval of 40–50 µm, which allows the power density of 116 mW/cm2 at 850°С to be reached. At the same time, with the transition from single-phase PCO cathodes to the composite PCO–Ce0.9Gd0.1O1.95 (60/40 wt %) cathodes the power density increases to 130 mW/cm2 at 850°С and the dynamics of its decrease with the decrease in temperature slows down. The analysis of impedance spectroscopy data on the total polarization resistance of model SOFCs with cathodes prepared by different methods shows that the transition from unmodified cells to cells with the thicker cathodic layer and also with composite cathodes decreases the level of polarization losses two-fold (in the former case) and three-fold (in the latter case). This is accompanied by the increase in the power density. The proposed methods of modifying the microstructure of the PCO-based cathode demonstrate the positive dynamics of growth of both the electrochemical performance of the cathode/electrolyte interface and the power density characteristics of the fuel cell as a whole. [ABSTRACT FROM AUTHOR]

A comparative analysis of the morphological features of horizons affected by paleoearthquakes revealed significant difference of seismites from lithologically different deposits. Powerful earthquakes determine not only the destruction of the sedimentary structure of near-surface deposits and their chaotic mixing, but also actively affect the underlying layers to a depth of several tens of meters; since the degree of diagenetic lithification of rocks in different horizons varies with depth, the nature of their seismogenic transformations also changes. It was found that major seismic events were associated with the time intervals of tectonic and paleogeographic restructuring of sedimentation basins, which consisted in the intensification of the basin floor subsidence and changes in the composition of sediments accumulated in the paleobasin. A special type of seismites was formed during the impact of earthquakes on siliceous deposits, which have been spanned by the diagenetic redistribution of authigenic mineral matter in a gel state. [ABSTRACT FROM AUTHOR]

We studied the mechanism of action of cytostatics with the addition of lysine acridone acetate to evaluate the possibility of its use for improving the effectiveness of antioncogenic therapy in colorectal cancer. In Nude mouse model, the level of apoptosis (TUNEL) and expression of proteins CD95, p53, Bcl-2, histone H3, and Ki-67 (immunohistochemistry) were assessed in primary tumor biopsy specimens. It has been shown that cytostatic treatment led to stimulation of p53-mediated apoptosis and suppression of proliferation (Ki-67 expression) of tumor cells, and apoptosis level was increased in groups receiving lysine acridone acetate. H3 expression in the experimental groups was changed. [ABSTRACT FROM AUTHOR]

The reaction of (perfluoroalkyl)furan-3(2H)-ones and β-diketone containing an acetal moiety with (hetero)aromatic 1,2-diamines was studied. Quinoxalines and pyrido[3,4-b]pyrazine bearing the enaminoketone fragment were ynthesized by the regioselective addition of a dinucleophile at the α-dicarbonyl moiety of polyketones. In the case of β-diketone containing acetal and ester groups, the conversion involves the α-ketoester moiety to form a quinoxalinyl-substituted 2,3-butanedione. All products were characterized by NMR spectroscopy and X-ray diffraction. [ABSTRACT FROM AUTHOR]

The results of optimizing the start-up mode of the tower crane slewing mechanism during steady trolleying are presented. the tower crane is considered to have a horizontal boom system. A dynamic model is developed. Differential equations of motion are derived from second-order Lagrange equations. An optimization problem is formulated. It includes the differential equations of motion of the boom system during slewing and trolleying, optimization criteria, and the boundary conditions of motion. A complex dimensionless criterion is used for optimization. The kinematic characteristics of the slewing mechanism that eliminate the oscillations of the load on a flexible suspension are chosen as boundary conditions. The solution of the optimal motion control problem is represented in the form of a polynomial with two terms, one ensuring the boundary conditions for crane slewing during steady trolleying, and the other minimizing the optimization criterion by choosing unknown coefficients. The Rot-Ring-PSO method is used to obtain the optimal operating mode for the slewing mechanism during steady trolleying. [ABSTRACT FROM AUTHOR]

We study the influence of concentrated forces and heat sources on the distribution of stresses in the interface of two different transversely isotropic half spaces. For this purpose, we construct fundamental solutions for a piecewise homogeneous transversely isotropic space subjected to the action of concentrated normal and tangential forces, as well as concentrated heat sources. Explicit expressions for these solutions are obtained by reducing the problem to the Riemann matrix problem in the space of generalized functions of slow growth for which we get the exact solutions. As a result, we obtain the distribution of normal stresses in the interface plane for different combinations of transversely isotropic materials in the presence of one or two concentrated forces, as well as in the presence of concentrated heat sources and concentrated forces. The results of numerical analyses reveal a significant influence of the thermoelastic characteristics of chosen materials of transversely isotropic half spaces and their combinations under the action of several concentrated forces and concentrated heat sources on the stress field in the interface plane. [ABSTRACT FROM AUTHOR]

The surface treatment of ultra-high-molecular-weight polyethylene (UHMWPE) in helium plasma at a pressure of 0.133 mbar has been studied by IR spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. It has been shown that the helium plasma treatment leads to the formation of double bonds in the UHMWPE surface layer and the associated formation of intermolecular crosslinks. The crosslinking of the surface layer is accompanied by a decrease in the nanowear of the UHMWPE surface by more than three orders of magnitude, which is confirmed by measurements using an atomic force microscope in the contact mode. [ABSTRACT FROM AUTHOR]

We studied the ability of an aqueous extract from yerba mate and a dry extract obtained on the basis of this aqueous extract to remove Fe(II) ions from an aqueous medium. Aqueous extracts from mate dose-dependently reduced the concentration of free Fe(II) ions assayed by the reaction with 1,10-phenanthroline. This can be attributed to polyphenolic compounds with iron-chelating properties present in aqueous extracts from mate, namely quercetin, rutin, caffeic and chlorogenic acids. These substances effectively removed Fe(II) ions from the medium (the initial concentration of these ions was 15 μM) in the concentration range of 20-30 μM. Binding of Fe(II) ions by aqueous mate extracts (due to the formation of chelate complexes with the participation of polyphenolic compounds) modified their absorption spectra in the visible region. Binding of Fe(II) ions can be a mechanism of the antioxidant action of yerba mate. [ABSTRACT FROM AUTHOR]

Cerium-containing tricalcium phosphate (TCP, Ca3(PO4)2) nanopowders with the whitlockite structure have been prepared via precipitation from solution. After heat treatment at 1300°C, the materials contained 0, 0.07, 0.18, and 0.39 wt % cerium, which corresponded to х = 0, 0.0025, 0.006, and 0.013 in the general formula Ca3 –хCe2х/3(PO4)2. The thermal stability of β-TCP has been shown to increase with increasing cerium content. The synthesized cerium-containing TCP powders show luminescence properties under excitation at wavelengths from 270 to 320 nm, with a peak emission wavelength from 360 to 390 nm, characteristic of Ce3+ luminescence. Varying the percentage of cerium in the materials and heat treatment temperature causes the emission spectrum to shift. [ABSTRACT FROM AUTHOR]

We investigate the spin transport and ferromagnetic resonance properties of giant magnetoresistance (GMR) Co/Cu-Ni multilayers with variable levels of Ni doping in the Cu spacer. We present an experimental evidence for a magnetic-to-diamagnetic transition in the atomic magnetic moment of Ni in the Cu matrix for concentrations below 15 at. % Ni. As its concentration is increased, Ni atoms turn into spin scattering centers, which is manifested experimentally as a step-like change in the GMR of the multilayers. This behavior is observed in multilayers with gradient-doped Cu spacers, where only the inner region was doped with Ni. In the uniformly doped spacers, the GMR decreases monotonously with increasing Ni content, indicating that Ni atoms are magnetic and act as spin relaxation centers in the entire dopant-concentration range studied. We explain the difference in the observed GMR behavior due to a strong magnetic proximity effect in the uniform spacers, which is efficiently suppressed in the gradient spacers. The observed magnetic phase transition is fully supported by our detailed ab initio calculations, taking into consideration structural relaxation in the system as well as potential Ni clustering. Controlling the loss or gain of the atomic magnetism for a specific dopant can be a tool in probing and controlling spin relaxation in materials and devices for spin-valve and spin-torque based applications. [ABSTRACT FROM AUTHOR]

Dispersion properties of electromagnetic eigenmodes in a semiconductor nanotube (with quadratic electron dispersion law) filled by a nonmagnetic dielectric and placed in a coaxial dc magnetic field are studied theoretically. A new quantum electrodynamical phenomenon is predicted. Namely, it is shown that increase in the electron density n 0 2 D in the nanotube results in the appearance of new branches in the eigenmodes spectrum. These branches arise in a bifurcation manner at some critical values of n 0 2 D , when a new electron energy subzone starts to fill in. The number of branches monotonously increases with growth n 0 2 D and oscillates with increase in the number of magnetic flux quanta through the nanotube (i.e., a peculiar Aharonov–Bohm effect takes place). We also found that the dispersion curves have parts with anomalous dispersion. The analytical expression for electron energy loss due to the excitation of eigenmodes under the Cherenkov resonance condition is derived and numerically analyzed. [ABSTRACT FROM AUTHOR]

A gas chromatographic study of the adsorption of vapors of organic compounds with different polarities on a carbon adsorbent with a bilayer based on a liquid crystal of the "double dovetail" type and unsubstituted β-cyclodextrin is performed. The thermodynamic characteristics of adsorption are determined from the temperature dependences of the Henry constants of adsorption. Comparison of the obtained thermodynamic characteristics of adsorption on an adsorbent with a monolayer of a liquid crystal and a liquid crystal–cyclodextrin bilayer is performed. It is shown that the modified with a bilayer adsorbent possesses moderate selectivity to weakly polar optical isomers under the conditions of gas adsorption chromatography. [ABSTRACT FROM AUTHOR]

The comparative characteristics of sedimentary successions corresponding to the paleoecological event OAE 2, which are spaced over 1000 km apart within the Crimean–Caucasian region, are present. It is shown that the sediments accumulated during this time span under different sedimentary conditions are featured by the similar structures. The sedimentological, geochemical, and paleoecological analyses, indicate that (1) stable oxygen deficient conditions were not spread in the water column of the paleobasin; they occurred locally in a thin layer of bottom water owing to the oxidation of organic matter accumulated on the seafloor; (2) geochemical anomalies inherent in the TOC-rich horizon extend to the embedding layers that indicate their involving to the paleoecological event. The carbonaceous sediments of OAE 2 formed due to the enhanced nutrients influx from the land during the eustatic transgression caused the dramatic increase in the plankton productivity. The transgression was complicated by frequent sea-level fluctuations of minor magnitude associated with the Milankovitch precession cycles. [ABSTRACT FROM AUTHOR]

The work is devoted to research on obtaining materials based on silicon and aluminum oxides from nepheline concentrate, the main component of which is the mineral nepheline. The obtained samples were studied by XRD, SEM, porosimetry, chemical analysis, etc. It has been established that all of them are X-ray amorphous substances with particle sizes from 40 to 300 nm, in which, according to chemical analysis, the mass ratio of Al2O3 : SiO2 is ≈ 1 : 1.2. The structural and acid-base properties of the surface of the synthesized samples have been studied. According to the porosimetry data, all samples are predominantly mesoporous substances with a developed specific surface area (Ssp = 380–450 m2/g). There is a directly proportional relationship between H2SO4 concentration used in the decomposition of the nepheline concentrate and the specific surface area of the synthesized compounds. Data are presented on the dependence of the specific surface charge of the obtained samples on the pH of the medium, which indicate that the point of zero charge for the synthesized substances shifts to a more acidic region with an increase in the concentration of H2SO4 taken for the decomposition of nepheline. [ABSTRACT FROM AUTHOR]

A method was proposed for the synthesis of substituted 2-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-ylamino)-4-oxobut-2-enoates containing a nitrile substituent in the thiophene ring by reacting the corresponding 3-thienylimino-3H-furan-2-ones with primary alcohols. The antinociceptive activity and acute toxicity of the obtained compounds were investigated. It was found that the substituted esters have pronounced antinociceptive activity and low toxicity. According to the classification of toxicity of drugs, the obtained substituted of 2-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-ylamino)-4-oxobut-2-enoates belong to the V class toxicity. [ABSTRACT FROM AUTHOR]

A method of identification of acoustic-gravity waves (AGWs) in the atmosphere according to the satellite measurement data has been proposed. It has been shown that the polarization relations between fluctuations of the wave parameters (velocity, density, temperature, and pressure) for freely propagating waves and evanescent wave modes are considerably different, which makes it possible to identify different types of atmospheric waves in the experimental data. A diagnostic chart was plotted that can be used for determining a wave type and its direction of the vertical motion based on the phase shifts of the observed parameters. Using phase shifts between the velocity fluctuations and thermodynamic parameters of the atmosphere, not only the wave type but also its spectral characteristics can be determined. Verification of the proposed method was performed for identifying polar wave perturbations based on the measurements from the Dynamics Explorer 2 low-orbit satellite. Verification showed that the polarization relations of AGWs in the thermosphere preferably correspond to the gravitational branch of acoustic-gravity waves, which freely propagate in the direction of bottom up. This conclusion agrees with other results of the observations of AGWs in the atmosphere and the ionosphere using the ground and satellite methods. The evanescent waves were not observed at the considered orbits of the satellite. [ABSTRACT FROM AUTHOR]

The problem of optimizing the motion of the trolley mechanism during steady slewing of a tower crane is solved. To this end, a mathematical model of the dynamics of the crane jig system is used. It is reduced to one linear differential equation of the sixth order that describes the dependence of the driving torque of the drive mechanism on the coordinate of the load center of mass and its time derivatives. Three variational problems are stated. The method for analytical solution of the problems is illustrated for one of the problems as an example. Three optimal, in terms of different criteria, modes of motion of the trolley mechanism are obtained. Each of them has its advantages and disadvantages. The obtained results are analyzed, and low- and high-frequency oscillations of the mechanism links are revealed. The conditions under which these oscillations are eliminated are established. [ABSTRACT FROM AUTHOR]

Abstract—Volumetric (non-shear) deformations of fault zones measured from leveling data are analyzed. It is shown that volumetric deformations within fault zones lead to symmetric local surface subsidence. Examples of anomalous subsidence identified in the Ashgabat fault zone (North Kopet Dag) and in the fault zones of the underground gas storage facility are presented. A mechanism describing the formation of these anomalous deformations based on the models of poroelastic inclusion and poroelastic inhomogeneity is proposed. The problem about surface displacements of elastic halfspace with a poroelastic region in the form of vertical extended rectangular prism simulating active fragment of a fault zone is solved. Analytical formulas for surface-displacement estimation are derived for two variants of poroelastic models: a model of inclusion and a model of heterogeneity. The comparison of the two models based on the case study of the Ashgabat fault has shown that the mechanism of anomalous deformations with poroelastic heterogeneity model much better describes the observed displacements than poroelastic inclusion model. The analysis of anomalous surface displacements at an underground gas storage facility indicates that local subsidence occurs during both gas withdrawal and injection. It is established that the formation of anomalous subsidence in the first case follows the poroelastic inclusion model, and in the second case it corresponds to the poroelastic heterogeneity model. This means that local subsidence in a fault zone during gas withdrawal is linearly related to the change in reservoir pressure. Anomalous subsidence during gas injection is nonlinearly linked to the change in reservoir pressure. This is a striking example of induced deformations in the fault zones when temporal variations of poroelastic parameters within a fault zone in the setting of external quasistatic loading induce local perturbation in the stress-strain state of rocks in the vicinity of fault. [ABSTRACT FROM AUTHOR]

Tri(meta-tolyl)antimony and triphenylantimony react with 2,6-dihydroxybenzoic and 3,5-dinitrosalicyclic acids in the presence of hydrogen peroxide to give triarylantimony dicarboxylates (I and II∙2PhH, respectively). The reaction of tris(5-bromo-2-methoxyphenyl)antimony with 2,6-dihydroxybenzoic acid gives binuclear organoantimony compound with a bridging oxygen atom (III∙MeCN). The structures of the products were determined by X-ray diffraction (CCDC nos. 1911551, 2117678, 1970910). [ABSTRACT FROM AUTHOR]

Bypass surgery is widely used in the treatment of cardiovascular diseases. The problem of optimal location of cerebral vascular anastomosis is considered. An electrical analogue of circulation in major cerebral vessels is constructed whose optimal parameters are determined numerically using swarm intelligence methods. The objective optimization function is taken to be the pressure after shunting compared with the pressure before surgery. This method is first used to solve the problem of the formation of cerebral vascular bypasses. It is shown that the obtained results are in good agreement with the data of real surgeries. [ABSTRACT FROM AUTHOR]

Copolymers of butyl acrylate and methyl methacrylate with vinyl butyl ether in excess at reflux of the latter were synthesized under comparable conditions gradually adding acrylic monomers to the reaction mixture. Azobisisobutyronitrile or a triethylborane—oxygen initiating system was used as the initiator. The molar ratio of the monomer units was determined for the isolated polymers by IR and 1H NMR spectroscopy. The 13C NMR spectra of the copolymers were interpreted in order to determine the degree of alternation of units. The microheterogeneity coefficients and average lengths of sequences of the same chain units determined from the 13C NMR spectra indicate that the copolymer with butyl acrylate has a microstructure close to the alternation of the ether and ester units in the chain, whereas in the copolymer with methyl methacrylate this structure is pronounced to a lower extent. [ABSTRACT FROM AUTHOR]

The purpose of the article was to study the seasonality of retail sales of substitution therapy medications for dry eye syndrome treatment over the period of five years (2016-2020) in comparison with the annual monthly variations, taking into consideration the probable atypy of the 2020 indices due to the influence of the pandemic. To achieve the stated goal, retrospective, structural and graphic methods were used; a marketing analysis of the national pharmaceutical market from the point of presence of substitution therapy medications for dry eye syndrome was conducted. The next stage was the identification of seasonal variations in the time series of sales of the medications for treatment of conditions accompanied by the dry eye syndrome in Ukraine over the period of 2016-2020. The analysis of retail sales of substitution therapy medications for dry eye syndrome treatment over the period of 2016-2020 indicates a steady presence of seasonal peaks in March, August and December. The information received in the course of the study is necessary both for the patients and the employees of pharmaceutical companies engaged in wholesale and retail sales of medicines and medical devices. In terms of the patients, there a possibility to use preventative measures in order to limit the influence of a number of studied aggressive factors. And on the Based on the indexes of the seasonal demand for dry eye syndrome substitution therapy medications, pharmaceutical enterprises will be able to form the corresponding stock of the necessary medications thus ensuring the exists actual availability of substitution therapy medications for the population. This will indirectly but positively impact the treatment of patients with dry eye syndrome. [ABSTRACT FROM AUTHOR]

The authors consider the creation of scientific and technical programs for conversion of nuclear research reactors at the decommissioning stage in terms of extending the designated service life of all operating nuclear research reactors (RRs) in Russia. To solve this problem, a methodology is proposed that includes an information model and a description of the necessary step-by-step actions, along with a set of appendices in the form of documents describing the best ways of creating a project for managing the quality of RR conversion in relation to special conditions of the life cycles of specific nuclear reactors. The methodology is described in the form of principles and means of construction and structure. An example of applying this methodology to the conversion of the Hydra salt solution pulse nuclear research reactor at the stage of decommissioning is presented. The reason for converting the Hydra reactor is to extend the designated service life by replacing nonrepairable equipment (the vessel). The main criteria for confirming the remaining service life of the vessel are formulated. They include the safety margin of the vessel's material with allowance for the fluence accumulated on the more vulnerable areas and confirming the integrity and tightness of the vessel. For clarity, the conceptual information model of the methodology for confirming the safety of replacing the Hydra reactor vessel is given in the form of an Ishikawa diagram. The methodology consists of a number of consecutive scientific and technical activities, studies, and a finite number of actions in order to achieve the ultimate goal of extending the service life. The stages of the methodology for confirming the safety of replacing the Hydra reactor vessel are described. These include clarifying the initial data, performing computational studies and laboratory experiments, clarifying the requirements of methodological documentation, creating a working plan, and preparing license documents of operation. [ABSTRACT FROM AUTHOR]

New substituted 2-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-ylamino)-4-oxo-4-phenylbut-2-enoates were obtained by the reaction of 2-((2-oxo-5-phenylfuran-3(2H)-ylidene)-amino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile with alcohols. The structures of the compounds obtained were confirmed by 1H and 13C NMR spectroscopy and elemental analysis. A number of new compounds were found to have a pronounced analgesic activity, as well as a weak antimicrobial effect or its absence. [ABSTRACT FROM AUTHOR]

New N′-substituted 2-(2-(diarylmethylene)hydrazinyl)-5,5-dimethyl-4-oxohex-2-enehydrazides were synthesized by the ring opening reaction of 3-diarylmethylenehydrazono-5-tert-butyl-3H-furan-2-ones under the action of aliphatic, aromatic, and heterocyclic acid hydrazides. The structures of the obtained compounds were confirmed by 1H and 13C NMR spectroscopy, IR spectroscopy, and elemental analysis. Their anti-inflammatory activity was studied. [ABSTRACT FROM AUTHOR]

The problems of the optimal control of a mechanical crane–load system are stated in three cases: acceleration, deceleration, and full cycle of motion. The problem statements include constraints for the maximum driving force and the maximum rate of its change with time. All the problems are discretized. The solutions in the form of feedback are obtained using the modified particle swarm optimization (ME-D-PSO) method. The obtained results are analyzed in terms of the extremal and root-mean-square indicators as well as duration of motion. [ABSTRACT FROM AUTHOR]