bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Peroxisome Proliferator-Activated Receptor γ on Modulating Angiopoietin-Like Protein 4 Synthesis in Caco-2 Cells Exposed to <i>Clostridium butyricum</i>
Authors: Zhao X. , Huang H. S. , Shi S. R. 
Published: April 2024

Angiopoietin-like protein 4 (ANGPTL4) is considered to be one of the important circulating mediators linking intestinal microorganisms and host lipid metabolism. The objective of this study was to assess the effects of peroxisome proliferator-activated receptor γ (PPARγ) on modulating ANGPTL4 synthesis in Caco-2 cells exposed to Clostridium butyricum. The viability of Caco-2 cells and the expression of PPARγ and ANGPTL4 in Caco-2 cells were detected after the Caco-2 cells were co-cultured with C. butyricum at the concentration of 1 × 106, 1 × 107 and 1 × 108 CFU/mL. The results showed that cell viability was enhanced by C. butyricum. Besides, PPARγ and ANGPTL4 expression and secretion in Caco-2 cells was significantly increased by 1 × 107 and 1 × 108 CFU/mL of C. butyricum. Furthermore, the effects of PPARγ on modulating ANGPTL4 synthesis in Caco-2 cells regulated by 1 × 108 CFU/mL of C. butyricum was also be expounded in PPARγ activation/inhibition model based on Caco-2 cells and via ChIP technique. It was found that C. butyricum promoted the binding of PPARγ to the PPAR binding site (chr19: 8362157-8362357, located upstream of the transcriptional start site of angptl4) of the angptl4 gene in Caco-2 cells. However, the PPARγ was not the only way for C. butyricum to stimulate ANGPTL4 production. Taken together, PPARγ played a role in the regulation of ANGPTL4 synthesis by C. butyricum in Caco-2 cells.
Miocene Hydrobiidae (Gastropoda) of the Eastern Paratethys
Authors: Guzhov A. V. 
Published: April 2024

A review of the family Hydrobiidae from the Tarkhanian and Chokrakian deposits was made. New genus Islamiella was described, in which the species I. miocenica sp. nov. (upper Tarkhanian–lower Chokrakian) and I. maeotica sp. nov. (lower Maeotian) were included. Last species is widely distributed in the facies, concomitant with the bryozoan buildings of the Maeotian beginning. Peringia tarkhanica sp. nov. was described fom the Tarkhanian, whereas Hydrobia kubanica Zhizhchenko, 1936 was redescribed from the Chokrakian. Several species descibed earlier as Hydrobia by Zhizhchenko were synonymized with the species from the other families: H. subprotracta Zhizhchenko, 1936 icluded in synonymy of Finella andrusovi andrusovi (Bajarunas, 1910), and H. stavropoliana Zhizhchenko, 1936 reffered to the genus Odostomia, most probably to species O. nuda Bajarunas, 1910.
Soil Respiration in Agrarian and Natural Ecosystems of the European Part of Russia
Authors: Sukhoveeva O. E. , Karelin D. V. , Zolotukhin A. N. , Pochikalov A. V. 
Published: April 2024

The results of the assessment of soil respiration (CO2 emission from soil) in three regions (Chuvash Republic, Ryazan and Kursk regions) are presented. Agrarian (crop and livestock) and natural ecosystems are combined into seven groups: croplands, pastures, hayfields, abandoned lands, forests, stockyards and open compost storages.CO2 emissions were measured in 2020–2022 using the close chamber method. Ecosystems were ranked by increasing rate of CO2 emission from soil in the following order: croplands (0.03–0.24 g C–CO2 m–2 h–1) pastures (0.07–0.33 g C–CO2 m–2 h–1) ≤ hayfields (0.06–0.35 g C–CO2 m–2 h–1) ≤ ≤ forests (0.07–0.28 g C–CO2 m–2 h–1) ≤ abandoned lands (0.08–0.37 g C–CO2 m–2 h–1) \( \ll \) stockyards (0.21–8.61 g C–CO2 m–2 h–1) \( \ll \) compost storages (1.15–13.85 g C–CO2 m–2 h–1). Estimates of CO2 emissions from pasture, hayfield, forest, and abandoned land soils were not statistically different in most cases. The dependence of soil respiration rate on hydrothermal (temperature and humidity of the upper soil layer, air temperature) and agrochemical (content of total carbon and total nitrogen in the upper soil layer, pH) indicators by geographical regions and by types of ecosystems was analyzed. The most important among the evaluated factors at both ecosystem and regional levels is soil temperature at the 10 cm depth (r = 0.41–0.88, p 0.05). Moisture conditions do not play a significant role in the formation of carbon flux. On the regional scale, the stocks of carbon and nitrogen are significant (r = 0.33–0.92, p 0.05), which are more dependent on the geographical location of sites than on the characteristics of economic activity. The considered indicators determine the variance of CO2 emission from soils of the studied ecosystems by 17–78%.
Solitary Waves in Two-Layer Fluid with Piecewise Exponential Stratification
Authors: Makarenko N. I. , Maltseva J. L. , Cherevko A. A. 
Published: April 2024

The problem on internal stationary waves in a two-layer fluid with density, depending exponentially on the depth inside the layers and having a jump at the interface, is considered. A non-linear equation of the second-order long-wave approximation is derived, and their asymptotic submodels, describing solitary waves of finite amplitude, are discussed. Dispersive properties and wave propagation regimes depending on dimensionless parameters of the background piecewise constant flow are studied.
Application of the Method of Fast Expansions to Construction of a Trajectory of Movement of a Body with Variable Mass from Its Initial Position in a Gained Final Position in a Gravitational Field
Authors: Chernyshov A. D. , Popov M. I. , Goryainov V. V. , Nikiforova O. Yu. 
Published: April 2024

An analytical solution of the problem of the movement of a spacecraft from the starting point to the final point in a certain time is given. First, the method of fast sine expansions is used. The space problem considered here is essentially non-linear, what necessitates the use of trigonometric interpolation methods, which surpass all known interpolations in accuracy and simplicity. In this case, the problem of calculating Fourier coefficients by integral formulas is replaced by the solution of an orthogonal interpolation system. In this regard, two cases are considered on the segment \(\left[ {0,a} \right]\): universal interpolation and trigonometric sine and cosine interpolations. A theorem on the rapid decrease of expansion coefficients is proved, and a compact formula for calculating the interpolation coefficients is obtained. A general theory of fast expansions is given. It is shown that in this case, the Fourier coefficients decrease significantly faster with the growth of the ordinal number compared to the Fourier coefficients in the classical case. This property makes it possible to significantly reduce the number of terms taken into account in the Fourier series, significantly increase the accuracy of calculations and reduce the amount of calculations on a computer. The analysis of the obtained solutions of the spacecraft motion problem is carried out and their comparison with the exact solution of the test problem is proposed. An approximate solution by the method of fast expansions can be taken as an exact one, since the input data of the problem used from reference books have a higher error.
Quaternion Regularization of Singularities of Astrodynamic Models Generated by Gravitational Forces (Review)
Authors: Chelnokov Yu.N. 
Published: April 2024

The article presents an analytical review of works devoted to the quaternion regularization of the singularities of differential equations of the perturbed three-body problem generated by gravitational forces, using the four-dimensional Kustaanheimo–Stiefel variables. Most of these works have been published in leading foreign publications. We consider a new method of regularization of these equations proposed by us, based on the use of two-dimensional ideal rectangular Hansen coordinates, two-dimensional Levi-Civita variables, and four-dimensional Euler (Rodrigues–Hamilton) parameters. Previously, it was believed that it was impossible to generalize the famous Levi-Civita regularization of the equations of plane motion to the equations of spatial motion. The regularization proposed by us refutes this point of view and is based on writing the differential equations of the perturbed spatial problem of two bodies in an ideal coordinate system using two-dimensional Levi-Civita variables to describe the motion in this coordinate system (in this coordinate system, the equations of spatial motion take the form of equations of plane motion) and based on the use of the quaternion differential equation of the inertial orientation of the ideal coordinate system in the Euler parameters, which are the osculating elements of the orbit, as well as on the use of Keplerian energy and real time as additional variables, and on the use of the new independent Sundmann variable. Reduced regular equations, in which Levi-Civita variables and Euler parameters are used together, have not only the well-known advantages of equations in Kustaanheimo–Stiefel variables (regularity, linearity in new time for Keplerian motions, proximity to linear equations for perturbed motions), but also have their own additional advantages: 1) two-dimensionality, and not four-dimensionality, as in the case of Kustaanheimo-Stiefel, a single-frequency harmonic oscillator describing in new time in Levi-Civita variables the unperturbed elliptic Keplerian motion of the studied (second) body, 2) slow change in the new time of the Euler parameters, which describe the change in the inertial orientation of the ideal coordinate system, for perturbed motion, which is convenient when using the methods of nonlinear mechanics. This work complements our review paper [1].
Activation of the Cannabinoid Receptors Suppresses Hyperexcitation of Rat Hippocampal Neuronal Networks <i>in vitro</i>
Authors: Maiorov S. A. , Kairat B. K. , Gaidin S. G. , Kosenkov A. M. , Zinchenko V. P. 
Published: April 2024

Cannabinoid receptors (CBRs) play a key role in various physiological processes, including neurogenesis, synaptic plasticity, immune modulation, cell apoptosis, metabolism regulation, cardiovascular and reproductive systems activity. Since activation of CBRs suppresses hyperexcitation and protect cells from death, their modulation may have therapeutic prospects in the treatment of such pathologies of the nervous system as mental disorders, epilepsy, Parkinson’s and Huntington’s disease, multiple sclerosis, spinal cord and brain injuries. This paper presents experimental data on the effects of the cannabinoid receptor agonist WIN 55,212-2 on the induced oscillations of intracellular Ca2+ concentration ([Ca2+]i) in two in vitro models of epileptiform activity. To study the neuroprotective properties of WIN 55,212-2, hyperexcitation was induced by the application of a GABA(A) receptor antagonist, bicuculline, or depolarizing doses of ammonium chloride. As experiments have shown, WIN 55,212-2 at a concentration of 100 nM and above significantly suppresses the [Ca2+]i oscillation frequency and reduces the basal [Ca2+]i level. At the same time, the amplitude of calcium oscillations also decreased in the presence of the agonist. WIN 55,212-2 at a concentration of 5 μM suppressed NH4Cl-induced [Ca2+]i oscillations in all neurons but caused a transient biphasic increase in the basal [Ca2+]i level in 20% of astrocytes. Thus, in this work, using various models of hyperexcitation of neuronal networks, we have demonstrated the potential antiepileptic effect of the cannabinoid receptor agonist WIN 55,212-2.
THE THERMAL CONDUCTIVITY OF MOLTEN MIXTURES OF СeCl<sub>3</sub>–MCl (M = Li, Na, K, Cs) SYSTEMS
Authors: Bobrova K. O. , Dokytovich V. N. 
Published: April 2024

The paper presents experimental data on the thermal conductivity of molten salt mixtures СeCl3–MCl, where M = Li, Na, K, Cs. The concentration of cerium trichloride varies from 0.25 to 0.75 mole percent in 0.25 increments. The initial salts of alkali metal chlorides were certified by DSC. The obtained values of melting temperatures are in good agreement with the literature data. Anhydrous cerium trichloride was obtained from cerium(IV) oxide in 2 stages: preparation of cerium crystalline hydrate and removal of water of crystallization. The measurements were carried out by the stationary method of coaxial cylinders in a nickel device in the temperature range individually selected for each composition. The relative measurement error does not exceed 5%. In this work, the convective and radiative contributions to heat transfer were estimated. The value of the product of Prandtl and Grashof numbers is less than 1000, which confirms the absence of convection. The calculated radiative contribution to heat transfer does not exceed 2.4%. The thermal conductivity of all investigated melts increases with increasing temperature. The concentration dependences of molten mixtures of cerium and alkali metal chlorides were obtained. The thermal conductivity decreases upon passing from Li to Cs, which is due to an increase in the radius of the alkali metal cation and, as a consequence, an increase in the interionic distance.
А Method for the Quantitative Determination of the Active Receptor of Beta-lactam Antibiotics BlaR-CTD for Bioanalytical Applications
Authors: Serchenya T. S. , Semizhon P. A. , Schaslionak E. P. , Harbachova I. V. , Vashkevich I. I. , Sviridov O. V. 
Published: April 2024

A sandwich bioassay for the quantitative determination of the recombinant beta-lactam receptor BlaR-CTD possessing ligand binding activity and immunoreactivity has been developed. In the bioassay system, BlaR-CTD present in a biological liquid or standard sample binds via its receptor site to ampicillin immobilized in a microplate well and interacts through the epitopes of its peripheral structure with specific polyclonal antibodies. The analytical sensitivity of the method proved to be 2 ng/mL, and its concentration range was 5–215 ng/mL. In the processes of heterological expression, isolation and reagent forms preparation, the biological activity of BlaR-CTD was monitored and its stability was evaluated. High purity recombinant beta-lactam receptor BlaR-CTD was obtained. The protein was shown to have a sufficiently high resistance to denaturation by chaotropic agents (urea and guanidine hydrochloride), and it was stable over a wide pH range. Also, we proposed the constructions and procedures of competitive bioassays for beta-lactam antibiotics using microplates (analytical sensitivity – 0.02 ng/mL, IC50 = 0.28 ng/mL) or chromatographic test-strips (detection limit 1–2 ng/mL), which are based on the receptor and antigenic properties of BlaR-CTD.
On the Relationship of Natural and Modified Radioresistance with Mast Cell Reactivity
Authors: Ushakov I. B. , Kordenko A. N. 
Published: April 2024

This study was caused by accumulation of the data concerning: 1) relationship between the general reactivity of the body and radioresistance; 2) essential role of mast cells in the formation of radiobiological effects; 3) significant individual features of body radioresistance. Purpose of the study was to identify the relationship of radioresistance indicators with the state of body reactivity, manifested by constitutionally determined features of connective tissue mast cells. Natural radioresistance and modifying effect of hypoxia, hyperoxia and indralin radioprotector were considered. The study was performed on 369 white male rats weighing 215–240 g. To determine the individual characteristics of radioresistance, total and cranio-caudal irradiation of animals was performed. As a hypoxic test, hypoxic gas mixture with 8% oxygen content was used. The criteria of radioresistance were 5- and 30-day survival, weight loss, early transient disability. Index of reactivity of skin mast cells was considered as the diagnostic sign. Relationship features between the level of mast cell reactivity and radioresistance indicators were revealed. It has been shown that the minimum level of natural radioresistance is typical for animals with a high index of mast cell response to hypoxia. The modifying effect of hypoxia during irradiation was manifested in all animals. Also, the highest level of modified radioresistance was observed in rats with average values of the mast cell reactivity index. At the same time, When indralin was used, its radioprotective effect was most pronounced in the group of animals with the maximum reaction of mast cells. The radiomodifying effect of oxygen is mostly expressed in rats with the maximum values of the mast cell reactivity index and is characterized by a decrease in 5-day survival and average life expectancy. The relationship between the characteristics of mast cells and radioresistance can serve as a basis for the development of methods for predicting individual natural and modified radioresistance.
Layered Composite Materials Based on Ti/Ta/Hf/Ceramic to Solve Tasks under Extreme Conditions
Authors: Kamynina O. K. , Vadchenko S. G. , Kovalev I. D. , Prokhorov D. V. 
Published: April 2024

Layered composite materials Ti/Ta/Hf/ ceramic were produced via self-propagating high-temperature synthesis (SHS) of pre-structured samples using metal foils (Ti, Hf, Ta, Ni) and reaction tapes (Ti + 0.65C), (Ti + 1.7B) and (5Ti + 3Si). Reaction tapes were prepared by cold rolling from powder mixtures. The microstructure, elemental and phase compositions of the synthesized multilayer composite materials were characterized by Scanning Electron Microscopy (SEM) and X-ray analysis. Their flexural strength was determined according to the scheme of three-point loading at temperatures of 25 and 1100°С. The microstructure analysis of produced materials showed that the joining in the combustion mode of metal foils and reaction tapes is provided due to reaction diffusion, mutual impregnation and chemical reactions occurring in reaction tapes and on the surface of metal foils. The formation of thin intermediate layers in the form of cermets and eutectic solutions provides the synthesized multilayer materials with good strength properties (up to 275 MPa at 25°С, up to 72 MPa at 1100°С). These results are of interest for the development of construction materials operating under extreme conditions.
Long-Term Dynamics of the Huge Anmangynda Aufeis in the North-East of Russia (1962–2021)
Authors: Zemlianskova A. A. , Alekseev V. R. , Shikhov A. N. , Ostashov A. A. , Nesterova N. V. , Makarieva O. M. 
Published: April 2024

The huge Anmangynda aufeis is located in the valley of the river of the same name in the Magadan region in North-East of Russia. This is the only in the world aufeis site with a 30-years period of ground-based observations (1962–1991). The materials of these observations were supplemented with data obtained from the analysis of Landsat and Sentinel satellite images for the period 2000–2021, as well as the results of field investigations carried out in 2020–2021. The long-term variability of the maximum area, volume and average thickness of ice, the dynamics of formation and destruction of the aufeis ice in the cold and warm periods of the year were analyzed. It was found that the maximum values of the area and volume of ice on the dates before the start of ablation decreased by 25 and 33%, respectively. In 2000–2021, the average values of the aufeis characteristics are estimated as 4.7 km2 and 7.1 million m3, while in 1962–1991 – 5.5 km2 and 8.5 million m3. The analysis of the intra-annual dynamics revealed that the Anmangynda aufeis being earlier the perennial formation has transformed to the seasonal one. Further researches of the Anmangynda aufeis will make possible to assess the influence of various factors, including climatic ones, on the processes of an aufeis formation and to forecast their changes in the future for the cryolitic zone of the North-East of our country.
Small Glaciers of the Putorana Plateau under Climate Change
Authors: Kovalenko N. V. , Popovnin V. V. , Gubanov A. S. , Polyhov A. A. , Uspenskaya Ye. I. 
Published: April 2024

Received November 14, 2022; revised May 24, 2023; accepted June 27, 2023The characteristic feature of the Putorana Plateau is that the glaciological objects here are mostly represented by small glaciers and perennial snow patches. Their regime and morphology have so much common features that separation of these two categories of nival glacial formations from one another is extremely difficult problem. The distinctions between results of earlier studies carried out in the 1970s (the USSR Glacier Inventory estimated local resources at 22 glaciers with a total area of 2.5 km2) and at the beginning of the current century (in 2005, V.A. Sarana identified 61 glaciers with a total area of 7 km2) are too large to make any reliable conclusions about the current trends of the Putoran glaciation. In such conditions, the materials of rare field monitoring work performed on individual nival-glacial bodies become very valuable. Three expedition seasons of 2002–2004 included thorough geodetic and mass-balance measurements on 3 reference objects on the northern ledge of Lama Mts. – Prives (No. 30) Glacier, Marlborough (No. 31) Glacier and Strudoms snow patch. Similar field monitoring was repeated in summer’2019. The change in their configuration according to digital photography data, including the results of the analysis of satellite images, make possible to reveal that interannual fluctuations in the area of each glacier occur due to different vector displacements of its different sections along their entire perimeters. In 2019, the somewhat unexpected good budget state of all 3 monitored objects was detected. It manifested itself in growth of their areas and increased fraction of firn basin as well as in larger water equivalent of the firn residue as this followed from results of snow surveys. This fact contradicts the previous conclusion about the steady trend of deglaciation on the Putorana Plateau. The favourable condition for small glaciers occurred here in 2019 was mainly caused by reduced ablation owing to the weakened insolation that resulted from tremendous forest fires in Siberia, remarkable by their abnormal intensity in this year.