Solid solutions of bismuth ferrite, in which Bi and Fe ions are replaced by Sm and Ti ions, with the general chemical formula Bi 0.88 Sm 0.12 Fe 1– x Ti x O 3 were obtained by solid-phase reactions. Crystal structure analysis, based on X-ray diffraction data and Raman spectroscopy results, indicates the coexistence of rhombohedral and orthorhombic phases in the studied compounds in the concentration range 0 ≤ x ≤ 0.1. It is shown that at room temperature, the residual magnetization of the compounds increases with increasing Ti ion concentration, reaching a maximum value at x = 0.08. With a further increase in the titanium ion concentration, a slight decrease in the residual magnetization is observed. It was found that a decrease in temperature leads to a decrease in the magnitude of magnetization caused by the Dzyaloshinskii–Moriya interaction, which is accompanied by a change in the lengths and angles of the Fe–O–Fe bonds and distortions of the FeO 6 octahedra.
The adsorption of Ni2+ ions by sorbents based on dolomite thermally activated at 800 °C (D-800), phosphated dolomite (PD), and Zr-modified PD (PD-Zr) was studied. It was found that D-800 sample was characterized by the highest sorption capacity (364 mg/g), while at the initial concentration of Ni2+ ions of 300 mg/L, the purification of aqueous solutions to the MPC standards for drinking water (< 0.1 mg/L) was achieved, and at C0 (Ni2+) of 50 mg/L, deep purification to a residual concentration of < 0.01 mg/L occurred. It was revealed that the absorption of Ni2+ ions by the D-800 sorbent is due to the heterogeneous precipitation of nickel hydroxicarbonate, and in the case of the PD sorbent, nickel hydrophosphate is formed. The results of desorption of Ni2+ ions from saturated sorbents indicated the occurrence of ion exchange with the participation of amorphous zirconium phosphate for the PD-Zr sample. The lowest desorption degree (<1 %) was demonstrated by samples D-800 and PD. In the dynamic sorption process, the granular sorbent D-800 provided purification of more than 1000 column volumes of solution with C 0 (Ni2+) 10 mg/L below the MPC standards for drinking water at a linear filtration rate of 20 m/h.
This article presents explicit analytical dependencies of the hydrodispersion coefficient of radionuclides on the moisture flow rate and the characteristics of their sorption during convective-diffusive transport in natural dispersed media. These dependencies are obtained based on the analysis of the asymptotic solution of the convective-diffusive transport equation for radionuclides, taking into account their non-equilibrium sorption and the presence of molecular diffusion. It has been shown that the coefficieron hydrodispersion of radionuclides has a quadratic dependence on the moisture flow rate and an inverse dependence on the mass transfer coefficient between radionuclides in the pore solution and those sorbed by the solid component of the dispersed medium. In the active layer of the territory, where there are periodic changes in the magnitude and direction of the convective moisture flow rate, it is recommended that the calculation of the convective-diffusive transfer of radionuclides be carried out with due consideration of the non-equilibrium nature of their sorption by the solid component. It has been established that in the active layer, the main contribution to the transport of radionuclides is made by hydrodispersion, which is determined by the average integral value of the square of the convective moisture flow velocity, and effective molecular diffusion. This results in a relatively low rate of transport of radionuclides in the active layer in the direction of aquifers, in the absence of closed catchment areas of slope runoff.
For the first time, phosphatidyl derivatives of a number of nucleosides were studied as substrates of phosphatidylacylhydrolase in phospholipolysis reactions. A new trigger mechanism has been proposed and studied that initiates the death of pathogenic and opportunistic microorganisms (Staphylococcus aureus and Candida spp. cells) due to their virulence, including the activity of their own type A phospholipases, under the action of medicinal forms of antibiotics (based on covalently and non-covalently modified lipoconjugates) of the purine (nelarabine, nitrogenous base guanine) and pyrimidine (brivudine, nitrogenous base uracil) series, which have a bactericidal effect. In terms of the resistance of forms to destruction in the digestive tract, it has been shown that brivudine lipoconjugates are most susceptible to hydrolysis with the participation of pancreatic phospholipase A(2), while nelarabine-based lipoconjugate is characterized by higher stability to phospholipolysis. It has been established that, since the rate of hydrolysis of lipoconjugates of nelarabine and brivudine by phospholipase A of the culture fluid of Candida sake and Staphylococcus aureus is 1.7 and 2 times higher, respectively, than that of phosphatidylcholine, they can serve as a basis for the demonstration of biocide-containing conjugates and facilitate the availability of the active substance due to increased hydrolyzability.
The consumption of high-calorie foods is one of the factors leading to the formation of obesity and related complications. This is based on epigenetic mechanisms, including the regulation of gene expression by microRNAs. The aim of the study is to investigate the effect of high fat diet on the expression of miR-335, as well as the genes FASN and SIRT 4 and the proteins they encode in the visceral adipose tissue of Wistar rats. For 8 weeks, in addition to the standard diet of the vivarium, the rats received animal fats (45 % of daily caloric intake). The relative expression of miR-335 and its target genes FASN and SIRT 4 was determined using real-time PCR, and the protein levels of FASN and SIRT 4 in visceral adipose tissue were measured by enzyme-linked immunosorbent assay (ELISA). It was established that against the background of high-fat diet there is an increase in miR-335 expression and a decrease in activity of lipogenic genes FASN and SIRT 4 in visceral fat tissue of rats, which is accompanied by an increase in blood glucose, development of insulin resistance, and disruption of lipid metabolism. The obtained results indicate the important role of miR-335 in regulating metabolic processes in adipose tissue and the prospect of its use as a therapeutic target for the prevention of complications associated with obesity.
The aim of this study was to evaluate the potential of gelatin nanoparticles as a means of increasing the efficacy and bioavailability of phytocompounds, in particular quercetin. The protective effect of native quercetin and quercetin incorporated into gelatin nanoparticles was studied by initiating oxidative stress in human keratinocytes with tert-butyl hydroperoxide. Cell viability was assessed using the PrestoBlue (TM) reagent, apoptotic and necrotic cells were detected by double intravital staining using an assay kit including annexin V-FITC. DNA damage was analyzed using the comet assay. The results demonstrated that encapsulation of quercetin into gelatin nanoparticles enables its application in aqueous suspensions without compromising its antioxidant capacity, gene-and cytoprotective effects under cellular oxidative stress conditions, indicating a high efficiency of quercetin release from this nanocarrier. Consequently, the utilization of gelatin nanoparticles represents a promising approach for improving the bioavailability and therapeutic efficacy of phytochemicals.
The subject of study comprises samples of M1 copper and copper alloys of the L63 and LZhMts66-4-7 grades obtained by radial-shear rolling. The patterns of formation of the structure and mechanical properties of ultrafine-grained copper and its alloys obtained by radial-shear rolling under ultrasonic treatment are established. The electron backscatter diffraction method is used to determine the orientations of individual grains, local texture, and identify phases in the samples under study. Local and general deformations, the number of recrystallized and deformed grains, their sizes and orientations are determined. The structure of ultrafine-grained materials and their mechanical properties are studied using X-ray diffraction analysis and scanning electron microscopy. The relationship between the parameters of ultrasonic action and the microstructure and physicomechanical properties of ultrafine-grained copper and brass samples is established. It is shown that ultrasonic action on materials after their radial-shear rolling at certain amplitudes of mechanical stresses promotes relaxation of the nonequilibrium structure of grain boundaries and, thus, the removal of internal stresses.
Carotenogenesis, composition and ratio of individual carotenoid components synthesized by Rhodotorula glutinis BIM Y-159 was investigated. It was found that peak level of carotenoid production (5.7 mg/g biomass) was reached during submerged fermentation of yeast in media with high concentration of carbohydrates (glucose 11 %) and deficiency of nitrogen nutrition. Cu2+ ions in concentration 0.5 mM stimulated production of carotenoids in R. glutinis BIM Y-159 by 17.5-17.8 %. Under optimal conditions the produced carotenoid complex is represented by torulene, torulorhodin, zeta- and (beta-carotenes plus an unidentified component. (beta-Carotene, torulene, and torulorhodin amount for 16 %, 40 % and 32 % of carotenoids synthesized by R. glutinis BIM Y-159.
Samarium (III) 1,1,1,6,6,6-hexafluoro-3,4-di(2-thiophenemethanone) hexanedionate-2,5 was obtained from thenoyltrifluoroacetone by electrochemical synthesis. Mass spectrometry and IR spectroscopy data showed that electrolysis resulted in the formation of both the tetraketonate ligand and the quasi-aromatic metallocycle, the main structural element of the chelate. The peripheral groups (trifluoromethyl and thenoyl) of the tetraketonate ligand were not transformed by the electric current. The resulting samarium chelate compound is a promising precursor for the synthesis of orange-emitting light-emitting diodes and active laser media.
In this work, for the first time, stable and economical compact finite-difference schemes of order of accuracy 2 + 4 and 4 + 4 are constructed for the simplest parabolic equation, based on the idea of the method of lines and Runge-Kutta methods for solving systems of nonlinear ordinary differential equations. In constructing the computational algorithm, only a three-point stencil is used for approximating the equation by the spatial variable, which allows us to use the well-known tridiagonal matrix algorithm for inverting the matrix in O(N) arithmetic operations, where N is the number of grid points in space. When constructing compact schemes of the same order based on the conventional integro-interpolation method leads only to absolutely unstable algorithms. Results of computational experiments are presented, illustrating the efficiency of the proposed algorithm.
This study investigates the properties of epoxy resin reinforced with carbon nanomaterials (graphene and multi-walled carbon nanotubes "Taunit M" and "Taunit MD"), focusing on their structural and optical characteristics, as well as the effects of atomic oxygen (AO) exposure, which is crucial for the application of such composites in low Earth orbit (LEO) conditions. Exposure to AO in LEO, with an average energy of similar to 5 eV, leads to the surface erosion of composites, resulting in significant mass loss. Experimental results indicate that the average erosion yield (Rm) is 1.07.10(-23) g/atom for the composite with "Taunit M" filler, 1.21.10(-23) g/atom for "Taunit MD", and 8.56.10(-24) g/atom for the graphene-filled composite. This effect occurs because carbon fillers undergo the oxidation and chemical sputtering under AO exposure, a typical behavior for materials used in space environments. After irradiation with an AO fluence of (1.7-30.0)10(20) atom/cm(2), a significant decrease in reflection coefficients (both specular and diffuse) is observed across a broad spectral range (0.2-25 mu m). Specular reflection decreased by 1.4 times for pure epoxy resin, and by 9.9, 15.8, and 13.6 times for samples filled with graphene, "Taunit M", and "Taunit MD", respectively. Diffuse reflection from the pure epoxy decreased by 1.2 times, while for graphene-, "Taunit M"-, and "Taunit MD"-filled samples, it decreased by 5.3, 16.7, and 9.0 times, respectively. These findings indicate that modifying epoxy resin with carbon nanomaterials followed by AO irradiation leads to the formation of a surface layer with high anti-reflective properties. Such materials, treated with low-energy oxygen plasma, are highly effective for use in optical and optoelectronic systems of spacecraft, as well as in terrestrial applications requiring materials with high absorption and low reflection.
In this article we have analyzed the possibility of endogenous ligands (thyroxine, fatty acids, heme) displacing bilirubin from its binding site in the first domain of the human serum albumin based on in silico experiments. The obtained data showed that the known binding site in the first domain of human serum albumin is not specific for bilirubin. Indeed, the inhibition constant of the albumin and bilirubin complex was 417.38 & micro;M, of the albumin and palmitic acid complex was 164.28 & micro;M, of the albumin and heme complex was 10.13 & micro;M, and of the albumin and thyroxine complex was 9.17 & micro;M. The binding of fatty acids by human serum albumin should lead to changes in the tertiary structure of the protein and the appearance of more specific binding sites for 4Z,15Z-Bilirubin IX alpha.
The article examines the problems of updating evolutionary theory in the context of the need to develop a strategy for a secure future, reveals its heuristic potential, and highlights the multiplicity of meanings in defining the contours of a new civilization. The article notes that a new civilization is associated with an environment for the preservation and possible transmission of cultural and civilizational heritage. Changes in human life imply a change in the functions of culture, a rethinking of the deep meanings of human existence and its values. However, these changes will not be borrowed from outside sources, but rather must grow within the framework of the old civilization. Culture encodes the historical experience of humanity’s civilizational development. It is argued that, under the current conditions, it is necessary to either choose the path of harmonizing socio-economic development with the laws of the biosphere and affirming a co-evolutionary strategy of interaction between society and nature, or face the inevitable path of self-destruction. This involves rethinking the challenges of civilizational development, overcoming entrenched stereotypes in the way we understand “civilizational theory” and “civilizational development”, and identifying the growth points of a new civilization. In modern conditions, evolutionary theory is complemented by a strategy of co-evolution: it forms and establishes new guidelines for human activity, puts forward new ecological regulations for nature use and the organization of social life, and affirms the values of biospheric ecological ethics, which aim to maintain and protect safe life and increase its diversity.
Solid solutions of bismuth ferrite, in which Bi and Fe ions are replaced by Sm and Ti ions, with the general chemical formula Bi0.88Sm0.12Fe1-xTixO3 were obtained by solid-phase reactions. Crystal structure analysis, based on X-ray diffraction data and Raman spectroscopy results, indicates the coexistence of rhombohedral and orthorhombic phases in the studied compounds in the concentration range 0 <= x <= 0.1. It is shown that at room temperature, the residual magnetization of the compounds increases with increasing Ti ion concentration, reaching a maximum value at x = 0.08. With a further increase in the titanium ion concentration, a slight decrease in the residual magnetization is observed. It was found that a decrease in temperature leads to a decrease in the magnitude of magnetization caused by the Dzyaloshinskii-Moriya interaction, which is accompanied by a change in the lengths and angles of the Fe-O-Fe bonds and distortions of the FeO(6 )octahedra.
A regioselective synthesis of boric acid esters derived from 24-epibrassinolide and 24-epicastasterone has been developed. The esterification proceeds under mild conditions with high efficiency, yielding the corresponding 22,23-borates of steroidal phytohormones as the sole products. Their plant growth-stimulating activity was evaluated using spring wheat (Triticum aestivum L.) as a model system. The compounds were applied via seed soaking in solutions at concentrations of 10-7 and 10-9 M for 24 hours. Germination rates were assessed after 7 days, while seedling height, root length, and fresh weight of both seedlings and roots were measured 10 days after the start of the treatment. The synthesized conjugates were found to enhance seed germination and stimulate the growth of above-ground parts (by 10-15 % relative to the control), as well as increase biomass accumulation (by 13-23 %) and root weight (by 8-22 %). These novel brassinosteroid derivatives (borates) exhibited higher plant growth-stimulating activity than the native hormones themselves.
The focus of this study is a linear control system with a periodic matrix of coefficients and program control. The matrix under control is constant, the number of columns does not exceed the number of rows and its rank is less than the number of columns. It is assumed that the control is nontrivial periodic, and the module of its frequencies, i. e., the smallest additive group of real numbers, including all Fourier exponents of this control, is contained in the frequency module of the coefficient matrix. For the system under consideration, the problem of control of the asynchronous spectrum is posed: to construct such a control from an admissible set so that the system has strongly irregular periodic solutions. In this case, the period of the solution is incommensurate with the period of the system. Previously, the solution of the formulated problem was carried out for various cases of degeneracy of the average value of the coefficient matrix. In this work, a new approach is implemented that directly concerns the coefficient matrix itself. Under the assumption that its upper left block is stationary and the oscillating part of the upper right block has the maximum column rank, both necessary and also sufficient conditions for the solvability of the asynchronous spectrum control problem are obtained for the class of systems under consideration.
As part of the research, an assessment of the genetic diversity of the Polesskaya horse population was carried out based on multiplex genotyping of DNA samples for 17 STR loci. The number of identified alleles (Na), observed (Ho), and expected (He) heterozygosity, the effective allele number (polymorphism level, Ae), and the Fis fixation index were analyzed. A relatively high genetic identity (0.91) was found between the subpopulations of Polesskaya horses of OJSC “Polesskaya Niva” in the Stolin District and the “Gorodoksky” Collective Farming Unitary Enterprise in the Luninets District, indicating their close genetic relationship and common origin. Based on the studied features of STR loci genetic polymorphism, rare and unique genotypes were identified, defining the value of the gene pool for stud breeding and biodiversity conservation. Overall, the results of the conducted studies show the preservation of genetic diversity with moderate manifestations of inbreeding, which is an important factor for the further development of programs to stabilize the reserves of plasticity of the Polesskaya horse population bred in the Republic of Belarus.
A new neural network algorithm for tracking objects observed in frames of video has been developed. The algorithm enables automatic detection of objects of one of the predefined types, reliable subsequent tracking, rapid redetection of the object if tracking was interrupted, and detection of a different object of the desired type if the tracked object disappears. Detection of the object of interest in video frames is performed using a neural network detector, and tracking is carried out by the developed algorithm using a neural network transformer.
Dynamic electrochemical impedance spectroscopy was used to examine the corrosion behavior of AZ31 magnesium alloy in 0.05 mol/dm(3) sodium chloride solution containing Na2MoO4 inhibitor, which was gradually added to the solution up to the concentration of 50 mmol/dm(3). The parameters of multisinusoidal impedance monitoring obtained under these conditions corresponded to the instantaneous concentration of the inhibitor at a specific point in time. This made it possible to establish the dependence of the calculated values of the protective effect on the concentration of molybdate ions in the solution. Based on the assumption that complete coverage of the surface by the inhibitor provides 100 % reduction of the corrosion rate and the surface degree coverage corresponds to the protective effect of the inhibitor, the adsorption curves of molybdate ions on the surface of AZ31 magnesium alloy were constructed utilizing Langmuir, Temkin, Flory-Huggins, and Frumkin adsorption models.
In this study, we demonstrate that Anderson localization of the electromagnetic field in a chain of coupled waveguides can be implemented to realize a multiple-output beam-splitter. We demonstrate that despite the inherently noisy character of Anderson localization, our beam-splitting device is able to realize hybridization of classical and non-classical states with several non-classical states as the output. This effect is illustrated by means of the example of single-photon state hybridization with the coherent state.
