Peculiarities of nonadditive changes in conductivity of nano-PDLC under influence of magnetite and single-wall carbon nanotubes

Studied in this work has been the effect of nanoparticles – magnetite and single-wall carbon nanotubes – separately and together on the conductivity of nematic liquid crystal 6CHBT dispersed in polyvinyl alcohol. Morphology of these films was analyzed using an electron microscope. When using selected technologyof homogenizing the mixture components, there takes place formation of liquid crystals dispersed in the polymer matrix with the average sizes of liquid-crystal droplets close to 500 nm (nanoPDLC). It has been found that simultaneous introduction of magnetite and nanotubes results in lowering the conductivity of nano-PDLC as compared to the total conductivity of nano-PDLC with each kind of nanoparticles separately. It has been suggested that the main mechanism of this effect lies in formation of deep centers for electron capture by complexes with different types of nanoparticles, which leads to a decrease in electronic conductivity through the polymer matrix

Peculiarities of nonadditive changes in conductivity of nano-PDLC under influence of magnetite and single-wall carbon nanotubes

Studied in this work has been the effect of nanoparticles – magnetite and single-wall carbon nanotubes – separately and together on the conductivity of nematic liquid crystal 6CHBTdispersed in polyvinyl alcohol. Morphology of these films was analyzed using an electron microscope. When using selected technology of homogenizing the mixture components, there takes place formation of liquid crystals dispersed in the polymer matrix with the average sizes of liquid-crystal droplets close to 500 nm (nano-PDLC). It has been found that simultaneous introduction of magnetite and nanotubes results in lowering the conductivity of nano-PDLC as compared to the total conductivity of nano-PDLC with each kind of nanoparticles separately. It has been suggested that the main mechanism of this effect lies in formation of deep centers for electron capture by complexes with different types of nanoparticles, which leads to a decrease in electronic conductivity through the polymer matrix

Influence of superionic nanoparticles Cu₆PS₅I on dielectric properties of nematic liquid crystal 6СНВТ

Within the frequency range 10…10⁶ Hz, the influence of Cu₆PS₅I nanoparticles on the dielectric properties of planar oriented liquid crystal 6СНВТ has been studied. It has been shown that nanoparticles lead to an increase in conductivity, but the conductivity dependence on concentration is non-monotonic function. It has been suggested that the reason of non-monotonic dependence of conductivity of 6СНВТ on the concentration of nanoparticles is significant influence of ion adsorption on the nanoparticle surface and increase in the viscosity of liquid crystal when introducing nanoparticles

ВЛИЯНИЕ ОЖИРЕНИЯ НА РАЗВИТИЕ И ПРОГРЕССИЮ ЗЛОКАЧЕСТВЕННЫХ НОВООБРАЗОВАНИЙ: ОБЗОР СОВРЕМЕННЫХ ДАННЫХ И НОВЫХ ТЕРАПЕВТИЧЕСКИХ МИШЕНЕЙ

Background. Type 2 diabetes mellitus, obstructive sleep apnea, osteoarthritis and certain types of cancer are known to correlate with obesity. The mechanisms underlying the link between metabolic disorders and cancer remain obscure, yet assuming a potentially important role of reduced insulin sensitivity, altered glucose metabolism in tumor cells (the so-called Warburg effect), changes in the spectrum of secreted adipokines or interaction with their cognitive receptors as well as changes in steroid sex hormone production.Material and methods. A search for articles published in peer-reviewed journals indexed in pubmed, Wos, scopus and Rsci was carried out. More than 150 articles devoted to the study of the relationship between metabolic disorders and tumor progression were analyzed, of which 69 were included in this review.Results. The main strategy of anticancer therapy is to suppress the proliferation of tumor cells and metastasis. However, one should take into consideration a significant role of additional factors that can enhance side effects of anticancer therapy, ensure the resistance of tumor cells to chemotherapy or change cancer cell metabolic profile. New data recently emerging in the literature indicate an important function of proteins such as t-cadherin and urokinase receptor (upar) and their possible involvement in the regulation of tumor cell metabolism, in particular, sensitivity to insulin and adipose tissue hormones. The review encompasses recent data on the involvement of t-cadherin and upar in the regulation of metabolism and proposes a model explaining the relationship between these proteins and metabolic disorders associated with the processes of carcinogenesis and chemoresistance of cancer cells.Conclusion. Understanding of the factors and mechanisms that support obesity and metabolic disorders is relevant both for the development of cancer preventive measures and optimization of therapeutic strategies for combating cancer.Актуальность. Известно, что диабет 2-го типа, синдром обструктивного апноэ сна, остеоартроз и ряд злокачественных новообразований коррелируют с ожирением. Механизмы, обусловливающие взаимосвязь метаболических нарушений с возникновением злокачественных опухолей, пока неизвестны; значительную роль может играть изменение чувствительности к инсулину и факторам роста, изменение спектра секретируемых адипокинов или особенности их взаимодействия с рецепторами, изменение содержания стероидных половых гормонов в организме, а также особенности метаболизма глюкозы в опухолевых клетках (так называемый эффект Варбурга).Материал и методы. Проведен поиск источников, включая научные, клинические и обзорные статьи, опубликованные в рецензируемых журналах, индексируемых в pubmed, Wos, scopus и РИНЦ. Проанализировано более 150 статей, посвященных изучению взаимосвязи метаболических нарушений с опухолевой прогрессией, из которых 69 включены в данный обзор.Результаты. Основная стратегия лечения опухолевых заболеваний заключается в подавлении пролиферации опухолевых клеток и процессов метастазирования. Возможно, что значительную роль в этих процессах играет ряд факторов, способных усиливать побочные эффекты противоопухолевой терапии, поддерживать резистентность опухолевых клеток или изменять их метаболический профиль. Имеются новые данные о функции таких белков, как Т-кадгерин и рецептор урокиназы (upaR), и их возможном участии в регуляции метаболизма опухолевых клеток, в частности чувствительности к инсулину и гормонам жировой ткани. Помимо адипокинов как уже известных посредников, участвующих в канцерогенезе, в обзоре описаны новые данные о роли Т-кадгерина и урокиназного рецептора upaR в регуляции обменных процессов. Предложена модель, объясняющая взаимосвязь этих белков и метаболических нарушений, ассоциированных с процессами канцерогенеза и химиорезистентности опухолевых клеток.Заключение. Понимание факторов и механизмов, поддерживающих ожирение и нарушения метаболизма, с точки зрения их роли в канцерогенезе актуально как для разработки профилактических мер, так и для оптимизации терапевтических стратегий борьбы с опухолевыми заболеваниями

Profiling of dynamics in protein–lipid–water systems: a time-resolved fluorescence study of a model membrane protein with the label BADAN at specific membrane depths

Profiles of lipid-water bilayer dynamics were determined from picosecond time-resolved fluorescence spectra of membrane-embedded BADAN-labeled M13 coat protein. For this purpose, the protein was labeled at seven key positions. This places the label at well-defined locations from the water phase to the center of the hydrophobic acyl chain region of a phospholipid model membrane, providing us with a nanoscale ruler to map membranes. Analysis of the time-resolved fluorescence spectroscopic data provides the characteristic time constant for the twisting motion of the BADAN label, which is sensitive to the local flexibility of the protein–lipid environment. In addition, we obtain information about the mobility of water molecules at the membrane–water interface. The results provide an unprecedented nanoscale profiling of the dynamics and distribution of water in membrane systems. This information gives clear evidence that the actual barrier of membranes for ions and aqueous solvents is located at the region of carbonyl groups of the acyl chains

Structure and Dynamics of Biological Systems: Integration of Neutron Scattering with Computer Simulation

The combination of molecular dynamics simulation and neutron scattering techniques has emerged as a highly synergistic approach to elucidate the atomistic details of the structure, dynamics and functions of biological systems. Simulation models can be tested by calculating neutron scattering structure factors and comparing the results directly with experiments. If the scattering profiles agree the simulations can be used to provide a detailed decomposition and interpretation of the experiments, and if not, the models can be rationally adjusted. Comparison with neutron experiment can be made at the level of the scattering functions or, less directly, of structural and dynamical quantities derived from them. Here, we examine the combination of simulation and experiment in the interpretation of SANS and inelastic scattering experiments on the structure and dynamics of proteins and other biopolymers

Temperature dependence of protein dynamics simulated with three different water models

The effect of variation of the water model on the temperature dependence of protein and hydration water dynamics is examined by performing molecular dynamics simulations of myoglobin with the TIP3P, TIP4P, and TIP5P water models and the CHARMM protein force field at temperatures between 20 and 300 K. The atomic mean-square displacements, solvent reorientational relaxation times, pair angular correlations between surface water molecules, and time-averaged structures of the protein are all found to be similar, and the protein dynamical transition is described almost indistinguishably for the three water potentials. The results provide evidence that for some purposes changing the water model in protein simulations without a loss of accuracy may be possible

Information sources in the educational activities of students of a medical university

The article presents the results of a study devoted to the study of information sources that students use during the period of distance learning due to the covid-19 pandemic. During the study, it was shown that 5th year students are aware of the existence of most authoritative sources of information, however, their application in the educational process is limited. It was also shown that 56% of students participate in additional educational activities 1-2 times a year or less, which requires the development of corrective measuresВ статье приведены результаты исследования, посвященного изучению информационных источников, к которым прибегают студенты в период дистанционного обучения, обусловленного пандемией «ковид-19». В ходе исследования было показано, что студенты 5 курса осведомлены о существовании большинства авторитетных источников информации, однако применение их в учебном процессе ограничено. Также было показано, что 56% студентов участвуют в дополнительных образовательных мероприятиях 1-2 раза в год и реже, что требует разработки корректирующих мероприятий