The role of aTp-dependent chromatin remodeling factors in chromatin assembly in vivo

Chromatin assembly is a fundamental process essential for chromosome duplication subsequent to DNA replication. In addition, histone removal and incorporation take place constantly throughout the cell cycle in the course of DNA-utilizing processes, such as transcription, damage repair or recombination. In vitro studies have revealed that nucleosome assembly relies on the combined action of core histone chaperones and ATP-utilizing molecular motor proteins such as ACF or CHD1. Despite extensive biochemical characterization of ATP-dependent chromatin assembly and remodeling factors, it has remained unclear to what extent nucleosome assembly is an ATP-dependent process in vivo. Our original and published data about the functions of ATP-dependent chromatin assembly and remodeling factors clearly demonstrated that these proteins are important for nucleosome assembly and histone exchange in vivo. During male pronucleus reorganization after fertilization CHD1 has a critical role in the genomescale, replication-independent nucleosome assembly involving the histone variant H3.3. Thus, the molecular motor proteins, such as CHD1, function not only in the remodeling of existing nucleosomes but also in de novo nucleosome assembly from DNA and histones in vivo. ATP-dependent chromatin assembly and remodeling factors have been implicated in the process of histone exchange during transcription and DNA repair, in the maintenance of centromeric chromatin and in the loading and remodeling of nucleosomes behind a replication fork. Thus, chromatin remodeling factors are involved in the processes of both replication-dependent and replication-independent chromatin assembly. The role of these proteins is especially prominent in the processes of large-scale chromatin reorganization; for example, during male pronucleus formation or in DNA repair. Together, ATP-dependent chromatin assembly factors, histone chaperones and chromatin modifying enzymes form a “chromatin integrity network” to ensure proper maintenance and propagation of chromatin landscape

Adhesive coatings based on aligned arrays of carbon nanostructures

This work was financially supported by Russian Foundation for Basic Research (projects 16-29-14023 and 18-32-00652) and Internal grant of the Southern Federal University (project VnGr-07/2017-26)

Pressure-induced phase transition of Bi2Te3 into the bcc structure

The pressure-induced phase transition of bismuth telluride, Bi2Te3, has been studied by synchrotron x-ray diffraction measurements at room temperature using a diamond-anvil cell (DAC) with loading pressures up to 29.8 GPa. We found a high-pressure body-centered cubic (bcc) phase in Bi2Te3 at 25.2 GPa, which is denoted as phase IV, and this phase apperars above 14.5 GPa. Upon releasing the pressure from 29.8 GPa, the diffraction pattern changes with pressure hysteresis. The original rhombohedral phase is recovered at 2.43 GPa. The bcc structure can explain the phase IV peaks. We assumed that the structural model of phase IV is analogous to a substitutional binary alloy; the Bi and Te atoms are distributed in the bcc-lattice sites with space group Im-3m. The results of Rietveld analysis based on this model agree well with both the experimental data and calculated results. Therefore, the structure of phase IV in Bi2Te3 can be explained by a solid solution with a bcc lattice in the Bi-Te (60 atomic% tellurium) binary system.Comment: 12 pages, 5 figure

Vertically Aligned Carbon Nanotubes Production by PECVD

This chapter presents the results of experimental studies of the PECVD technological mode parameters’ influence on the formation of catalytic centers and carbon nanotubes’ (CNTs’) growth processes. This chapter also presents the ability to regulate the growth parameter for the controlled production of CNTs with the required geometric parameters, properties, and growth mechanisms. The results of experimental studies of the heating temperature and activation time effects on the catalytic center formation will be presented. This chapter also shows the effects of growth temperature, heating rate, and the activation time on the geometric and structural parameters of the carbon nanotubes. Experimental studies were carried out with the use of AFM, SEM, TEM, and EXAFS techniques. The results can be used in the development of technological processes for creating ultrafast energy-efficient electronic component base with carbon nanostructures, particularly nanoelectromechanical switches, flexo- and piezoelectric generators, gas sensors, and high-performance emitters

In vitro antifungal activity of metal complexes of a quaternized chitosan derivative with copper ions

© 2017, Pleiades Publishing, Ltd. Antifungal activity of synthetic metal complexes of quaternized N-(propyl) chitosan derivatives with Сu(II) against yeastlike (Saccharomyces cereviseae, Rodothorula rubra, and Candida albicans) and mycelial fungi (Fusarium oxysporum, Alternaria alternata, Cladosporium herbarum) was studied. In vitro application (at 250‒500 μg/mL) of the metal complex of quaternized N-(propyl) derivative of low-molecular chitosan with 53% substitution and 1.3% copper ions proved efficient against F. оxysporum, one of ten most common fungal plant pathogens. Water-soluble quaternized N-(propyl) chitosan derivatives with 40−58% degree of substitution were synthesized using glycidyltrimethylammonium chloride under optimally adjusted conditions. Metal complexes of the chitosan derivative with 53% degree of substitution with Сu(II) ions were obtained by dialysis. The quantity of copper ions in the metal complexes was determined by atomic emission spectrometry. The structure of chitosan derivatives was confirmed by spectral analysis (IR, 1 H NMR)

Application of Probe Nanotechnologies for Memristor Structures Formation and Characterization

This chapter presents the results of experimental studies of the formation and investigation of the memristors by probe nanotechnologies. This chapter also perspectives and possibilities of application of local anodic oxidation and scratching probe nanolithography for the manufacture of memristors based on titanium oxide structures, nanocrystalline ZnO thin film, and vertically aligned carbon nanotubes. Memristive properties of vertically aligned carbon nanotubes, titanium oxide, and ZnO nanostructures were investigated by scanning probe microscopy methods. It is shown that nanocrystalline ZnO films manifest a stable memristor effect slightly dependent on its morphology. Titanium oxide nanoscale structures of different thicknesses obtained by local anodic oxidation demonstrate a memristive effect without the need to perform any additional electroforming operations. This experimentally confirmed the memristive switching of a two-electrode structure based on a vertically aligned carbon nanotube. These results can be used in the development of designs and technological processes of resistive random access memory (ReRAM) units based on the memristor devices

Scanning Probe Techniques for Characterization of Vertically Aligned Carbon Nanotubes

This chapter presents the results of experimental studies of the electrical, mechanical and geometric parameters of vertically aligned carbon nanotubes (VA CNTs) using scanning probe microscopy (SPM). This chapter also presents the features and difficulties of characterization of VA CNTs in different scanning modes of the SPM. Advanced techniques for VA CNT characterization (the height, Young’s modulus, resistivity, adhesion and piezoelectric response) taking into account the features of the SPM modes are described. The proposed techniques allow to overcome the difficulties associated with the vertical orientation and high aspect ratio of nanotubes in determining the electrical and mechanical parameters of the VA CNTs by standard methods. The results can be used in the development of diagnostic methods as well as in nanoelectronics and nanosystem devices based on vertically aligned carbon nanotubes (memory elements, adhesive structures, nanoelectromechanical switches, emission structures, etc.)

Investigation of the effect of upper electrode material on the memristor properties of strained carbon nanotubes

The reported study was funded by RFBR according to the research project No. 16-29-14023 ofi_m

Management of academic staff activity: modeling and prediction of rating system indicators

This paper deals with the problem of constructing a system of rating indicators for stimulating the work of the academic staff in higher educational institution. Many areas of teacher activity (for example, educational, scientific, international, etc.) laid the basis of selection the groups of indicators in the system. Social challenge in improving the quality of educational services determines the relevance of research in the field of modeling and prediction of indicators which characterize the work of high school teacher. To predict the dynamics of the structure of the rating indicators in the system, the authors introduced the concept of drift and variability of each group. Using informational hypercube for the structure of input data allowed authors to take into account the individual characteristics of each parameter included in a mathematical model to describe the rating indicators. To make the prediction of the structure and values of rating system indicators the authors introduced the concept of drift. Drift of indicators takes into account the introduction of new indicators, the removal of existing indicators, and movement of indicators between the groups. In the article, authors introduced a novel quantitative indicator of group variability. The value of this indicator determines the prediction strategy of the teacher work in higher school in the future period. To predict the total amount of stimulating, the complex technique offered and it includes four modules: modeling values within the existing range in the previous period; modeling new index value based on the assumptions introduced using a random number generator; exclusion a range of values of deleted indicators; modeling new values based on the study of the modern trend of indicators. The presence of flexible information structure in the form of a hypercube and complex mathematical model allowed authors to carry out numerical simulation for predicting the values of individual and group indicators. During the experiment, the structural stability of values is detected, and it does not lead to a drastic changing of the quantitative ratio between the groups of indicators

Features of Electronic States in the Vicinity of Band Gap and Atomic Structure of Ta- and Nb-Doped Li7La3Zr2O12

Received: 25.04.2024. Revised: 05.05.2024. Accepted: 05.05.2024. Available online: 06.05.2024.Li7La3Zr2O12 is one the most promising materials for Li-conducting solid electrolytes. The incorporation of Ta5+ and Nb5+ into the Zr4+ sites stabilizes its cubic structure and significantly enhances Li-conductivity, due to the formation of Li vacancies. In this research, we have studied the band gap features of Ta and Nd-doped Li7La3Zr2O12. Our findings indicate that Nb ions are present not only in the +5 valence state, but also in the +4 state, leading to the formation of oxygen vacancies. In the case of the Tadoping, such an effect was not observed. This could be the reason for the approximately one order of magnitude higher lithium conductivity observed in the case of the Ta doping, in comparison to the Nb doping.This work (except NMR measurements and NMR data analysis) was funded by the Russian Science Foundation (grant no. 22-73-00261), https://rscf.ru/en/project/22-73-00261/.This work was performed using equipment of the Shared Access Center “Composition of Compounds”. NMR measurements and NMR data analysis were performed by Germov A.Yu. in M.N. Mikheev Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences (topic “Function”)