Dagestan State University (Russian: Дагестанский государственный университет) is a public university in Makhachkala, Republic of Dagestan which is a federal subject in the Russian Federation. It is one of the largest higher educational institutions in Dagestan and a major scientific and cultural center. It was founded in 1931 as the Teachers' Training Institute, and later, in 1957 it was transformed into Dagestan State University (DSU) named after the national poet of Dagestan Suleyman Stalsky. The university includes 16 scientific and educational centers, 17 faculties, 97 departments, 4 branches, 2 museums (biological and historical), a fundamental library, a biological station and a planetarium. The university employs about 3,000 teachers and staff..
This study presents a comprehensive investigation of the CoFe2O4–Pb2ScNbO6 (0.5CFO–0.5PSN) composite, synthesized via a solid-state reaction method. The composite, comprising a ferrite spinel and a relaxor ferroelectric, was characterized using a suite of techniques including dielectric spectroscopy, optical analysis, X-ray diffractometry, magnetometry, magnetodielectric measurements and electrocatalytic testing. At room temperature, the real part of the complex permittivity (ε′) attains a value of 105. Within the temperature range of 100–250 °C, ε′ increases significantly to approximately 1.4 × 106. The temperature dependence of permittivity, ε′(T), exhibits a relaxor behaviour, which is attributed to the diffuse phase transition inherent to the PSN component and contributions from Maxwell–Wagner interfacial polarization. A distinct anomaly in the ε′(T) curve is observed near 450 °C, manifested as a kink followed by a sharp increase. This feature is associated with the transition of the CFO component from a ferrimagnetic to a paramagnetic state. The analysis of the magnetoresistance coefficient, MR(H), reveals that the composite exhibits colossal magnetoresistance (CMR) on the order of 530
Hibernation is an important adaptive strategy for survival in adverse environmental conditions, including temperature reduction. The heart of hibernating animal species is quite resistant to cold-induced arrhythmia. However, the cellular basis of hibernating mechanisms has not been fully studied. One of the possible mechanisms of protection from cold-induced arrhythmias during hibernation is the remodeling of ion channels in cardiomyocytes, which can be accompanied by remodeling of the T-system. Therefore, the aim of this work was to compare the electrophysiological parameters of the heart of the little ground squirrel S. pygmaeus during the periods of activity and hibernation. To achieve this goal, extracellular action potentials (eAPs) were recorded. The eAPs of the ground squirrel heart are signals of two types: eAP1 from the sarcolemma areas free of the T-tubule openings, and eAP2 from the areas including the T-tubule openings. During the hibernation period statistically significant changes in the eAPprofiles are observed, manifested in a decrease in the amplitude of the second peak of eAP2, an increase in the duration of the decay to 90% (T-90) in eAP1 and its shortening in eAP2. In addition, in hibernating ground squirrels, the profiles of both eAP types are accompanied by a significantly increased phase of afterhyperpolarization (AHP). Substantial changes during hibernation are also observed in the ratio of the eAP1 and eAP2 towards an increase in the number of eAP1. Similar changes in the ratio of different types of eAPs, shown by us for rats with type I diabetes mellitus, were associated with changes in the T-tubule system. However, preliminary results of studying ground squirrel hearts with confocal microscopy did not reveal visible differences in the organization of the T-system. This presumably indicates that hibernating ground squirrels have a considerably lower density of functional T-tubules due to a decrease in the density of ion channels in the T-system membrane.
The North Caucasus and Caspian region of Russia (NCCR) is a distinctive macroregion with rich cultural heritage, complex ethnic composition, favourable geographic location, and relatively developed infrastructure. However, its production systems lag behind national averages, and long-standing ethno-confessional and socioeconomic features continue to constrain development. This study examines the economic conditions of 11 NCCR regions using Rosstat's methodology for calculating indicators of regional production systems. The indicators are grouped into three categories: population characteristics; the state and development of production capacity; and organizational performance. Some indicators are used in their original form, while others are normalized to ensure comparability. The analysis suggests that the low performance of the economic system in the NCCR macroregion stems not from resource scarcity but from institutional constraints that limit the effectiveness of federal development programs. Although the region's overall lag behind national averages does not extend to agriculture, the sector's high share in gross regional product typically reflects underdevelopment in other parts of the economy. The lowest official economic indicators are concentrated in areas with predominantly indigenous ethnic populations. A large informal economy further distorts official statistics, obscuring actual household incomes and business activity, which complicates assessment of both regional economic conditions and the effectiveness of state support measures. The findings may be useful for designing regional socioeconomic development programs and for developing baseline methodologies to evaluate their effectiveness.
A combined quantum-chemical and molecular dynamics study of atomic layer etching of amorphous zinc oxide by β-diketones—acetylacetone, 1,1,1-trifluoroacetylacetone, and 1,1,1,5,5,5-hexafluoroacetylacetone—was carried out using the ORCA 6.0.1 and LAMMPS software packages. Within the framework of density functional theory at the PBE-D3BJ/def2-SVP level, the energy parameters of adsorption and desorption were investigated, and the induced surface stress was quantitatively evaluated. It has been found that acetylacetone induces the highest surface stress (1.62 eV) and enables spontaneous etching due to its low desorption energy (2.10 eV). The fluorinated derivatives exhibit a self-limiting interaction behavior: 1,1,1-trifluoroacetylacetone, with a desorption energy of 3.27 eV, induces a surface stress of 1.05 eV, while 1,1,1,5,5,5-hexafluoroacetylacetone causes the weakest effect on the surface structure (1.01 eV) with a desorption energy of 2.53 eV. The results suggest that 1,1,1-trifluoroacetylacetone can be considered the most suitable precursor for controlled atomic layer etching of zinc oxide.
A comparative analysis of the surface processes of atomic layer deposition (ALD) of AlMoxOy using H2O, molybdenum dioxide (MoO2Cl2), and trimethylaluminum (Al(CH3)3, TMA) or aluminum chloride (AlCl3) has been carried out. The effect of the aluminum precursor nature on the composition and oxidation state of molybdenum in the films has been studied. According to X-ray photoelectron spectroscopy evidence, the molybdenum content in the obtained films is lower than the aluminum content. Molybdenum with oxidation states Mo+6, Mo+5, and Mo+4 was also detected in the films; the ratio of the atomic concentration of Mo+6 to the reduced forms was 0.76 : 1 in the case of the TMA process, and 6.3 : 1 in the case of AlCl3. Replacing TMA with AlCl3 in the ALD of AlMoxOy decreased the amount of reduced Mo in the films, as well as the total molybdenum content. To evaluate the thermodynamic parameters of the proposed reactions for the ALD processes using AlCl3 and TMA, quantum-chemical DFT calculations were performed, which enabled the explanation for the observed differences in the films.
