Effect of Alloying Oxides Y2O3 and ZrO2 on the Microstructure of Austenitic Steel 18Cr10NiTi

Nanomaterials are materials of new generation with unique characteristics which are not characteristic for other materials. Nanofilms, nanoprocessors, nanorobots – the more well known technologies, but demands of modern industry, electronic industry, power industry dictate the development of nanomaterials in higher scales. The use of nanomaterials is very promising direction in nuclear power. Conditions of operation of structural materials in nuclear reactors, namely, high temperature (higher 300°C for thermal reactors and higher 600°C for fast reactors) which together with high density of neutrons (~1021-1022 neutrons/cm-2) cause the degradation of initial physical-chemical characteristics and the significant dimension changes. These factors influence considerably on safe and long-term operation period of reactor

Effect of Alloying Oxides Y2O3 and ZrO2 on the Microstructure of Austenitic Steel 18Cr10NiTi

Nanomaterials are materials of new generation with unique characteristics which are not characteristic for other materials. Nanofilms, nanoprocessors, nanorobots – the more well known technologies, but demands of modern industry, electronic industry, power industry dictate the development of nanomaterials in higher scales. The use of nanomaterials is very promising direction in nuclear power. Conditions of operation of structural materials in nuclear reactors, namely, high temperature (higher 300°C for thermal reactors and higher 600°C for fast reactors) which together with high density of neutrons (~1021-1022 neutrons/cm-2) cause the degradation of initial physical-chemical characteristics and the significant dimension changes. These factors influence considerably on safe and long-term operation period of reactor

Pulsar Wind Nebulae with Bow Shocks: Non-thermal Radiation and Cosmic Ray Leptons

Pulsars with high spin-down power produce relativistic winds radiating a non-negligible fraction of this power over the whole electromagnetic range from radio to gamma-rays in the pulsar wind nebulae (PWNe). The rest of the power is dissipated in the interactions of the PWNe with the ambient interstellar medium (ISM). Some of the PWNe are moving relative to the ambient ISM with supersonic speeds producing bow shocks. In this case, the ultrarelativistic particles accelerated at the termination surface of the pulsar wind may undergo reacceleration in the converging flow system formed by the plasma outflowing from the wind termination shock and the plasma inflowing from the bow shock. The presence of magnetic perturbations in the flow, produced by instabilities induced by the accelerated particles themselves, is essential for the process to work. A generic outcome of this type of reacceleration is the creation of particle distributions with very hard spectra, such as are indeed required to explain the observed spectra of synchrotron radiation with photon indices Γ≲ 1.5. The presence of this hard spectral component is specific to PWNe with bow shocks (BSPWNe). The accelerated particles, mainly electrons and positrons, may end up containing a substantial fraction of the shock ram pressure. In addition, for typical ISM and pulsar parameters, the e+ released by these systems in the Galaxy are numerous enough to contribute a substantial fraction of the positrons detected as cosmic ray (CR) particles above few tens of GeV and up to several hundred GeV. The escape of ultrarelativistic particles from a BSPWN—and hence, its appearance in the far-UV and X-ray bands—is determined by the relative directions of the interstellar magnetic field, the velocity of the astrosphere and the pulsar rotation axis. In this respect we review the observed appearance and multiwavelength spectra of three different types of BSPWNe: PSR J0437-4715, the Guitar and Lighthouse nebulae, and Vela-like objects. We argue that high resolution imaging of such objects provides unique information both on pulsar winds and on the ISM. We discuss the interpretation of imaging observations in the context of the model outlined above and estimate the BSPWN contribution to the positron flux observed at the Earth

GRAIN BOUNDARY DISTRIBUTION IN MATERIALS SUSCEPTIBLE TO ANNEALING TWINNING

Grain boundary distributions in various materials with low and medium stalking fault energy subjected to different recrystallization annealings were investigated. It was established that grain boundary spectra in all these materials are similar. The main feature of these spectra is that most of the boundaries are Σ3n boundaries. A model grain boundary spectrum was obtained by computer simulation based on the assumption that Σ3n boundaries formed as a result of multiple twinning played a dominant role in the grain boundary ensemble. The model boundary distribution agrees well with the experimental data. The conclusion is made that in materials susceptible to annealing twinning most (or almost all) of the grain boundaries are Σ3n boundaries and the distribution of these boundaries characterizes some stable state toward which the grain boundary ensemble tends during its evolution

Biomarkers and utility of the antioxidant potential of probiotic lactobacilli and bifidobacteria as representatives of the human gut microbiota

Lactobacilli and bifidobacteria are an important part of human gut microbiota. Among numerous benefits, their antioxidant properties are attracting more and more attention. Multiple in vivo and in vitro studies have demonstrated that lactobacilli and bifidobacteria, along with their cellular components, possess excellent antioxidant capacity, which provides a certain degree of protection to the human body against diseases associated with oxidative stress. Recently, lactobacilli and bifidobacteria have begun to be considered as a new source of natural antioxidants. This review summarizes the current state of research on various antioxidant properties of lactobacilli and bifidobacteria. Special emphasis is given to the mechanisms of antioxidant activity of these bacteria in the human gut microbiota, which involve bacterial cell components and metabolites. This review is also dedicated to the genes involved in the antioxidant properties of lactobacilli and bifidobacteria strains as indicators of their antioxidant potential in human gut microbiota. Identification of the antioxidant biomarkers of the gut microbiota is of great importance both for creating diagnostic systems for assessing oxidative stress and for choosing strategies aimed at restoring the normal functioning of the microbiota and, through it, restoring human health. In this review, the practical application of probiotic strains with proven antioxidant properties to prevent oxidative stress is also considered. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

The Lactobacillus rhamnosus and Lactobacillus fermentum strains from human biotopes characterized with MLST and toxin-antitoxin gene polymorphism

The diversity of Lb. rhamnosus and Lb. fermentum strains isolated from feces, saliva, and the vaginal cavity of 18–22-year-old healthy women residing in central regions of the Russian Federation has been characterized. The results obtained using multilocus sequence typing were identical to those obtained with the analysis of genetic and genomic polymorphism in TA systems. Different as well as identical Lb. rhamnosus and Lb. fermentum sequence types (ST) were isolated from various parts of the body of the same person. Identical ST were also isolated from different women, suggesting that such strains belong to a common pool of strains circulating among the population members. Our results demonstrate that TAs are suitable for characterizing intra-specific diversity of Lb. rhamnosus and Lb. fermentum strains. The advantage of using polymorphisms in TA systems for genotyping is based on the weak number of genes used, and consequently, less time is required for the analysis. © 2017, Springer-Verlag Berlin Heidelberg

The Lactobacillus rhamnosus and Lactobacillus fermentum strains from human biotopes characterized with MLST and toxin-antitoxin gene polymorphism

The diversity of Lb. rhamnosus and Lb. fermentum strains isolated from feces, saliva, and the vaginal cavity of 18–22-year-old healthy women residing in central regions of the Russian Federation has been characterized. The results obtained using multilocus sequence typing were identical to those obtained with the analysis of genetic and genomic polymorphism in TA systems. Different as well as identical Lb. rhamnosus and Lb. fermentum sequence types (ST) were isolated from various parts of the body of the same person. Identical ST were also isolated from different women, suggesting that such strains belong to a common pool of strains circulating among the population members. Our results demonstrate that TAs are suitable for characterizing intra-specific diversity of Lb. rhamnosus and Lb. fermentum strains. The advantage of using polymorphisms in TA systems for genotyping is based on the weak number of genes used, and consequently, less time is required for the analysis. © 2017, Springer-Verlag Berlin Heidelberg

Toxin-antitoxin systems: A tool for taxonomic analysis of human intestinal microbiota

The human gastrointestinal microbiota (HGM) is known for its rich diversity of bacterial species and strains. Yet many studies stop at characterizing theHGMat the family level. This is mainly due to lack of adequate methods for a high-resolution profiling of the HGM. One way to characterize the strain diversity of the HGM is to look for strain-specific functional markers. Here, we propose using type II toxin-antitoxin systems (TAS). To identify TAS systems in the HGM, we previously developed the software TAGMA. This software was designed to detect the TAS systems, MazEF and RelBE, in lactobacilli and bifidobacteria. In this study, we updated the gene catalog created previously and used it to test our software anew on 1346 strains of bacteria, which belonged to 489 species and 49 genera. We also sequenced the genomes of 20 fecal samples and analyzed the results with TAGMA. Although some differences were detected at the strain level, the results showed no particular difference in the bacterial species between our method and other classic analysis software. These results support the use of the updated catalog of genes encoding type II TAS as a useful tool for computer-assisted species and strain characterization of the HGM. © 2020 by the authors

Repurposing Based Identification of Novel Inhibitors against MmpS5-MmpL5 Efflux Pump of Mycobacterium smegmatis: A Combined In Silico and In Vitro Study

In the current era of a pandemic, infections of COVID-19 and Tuberculosis (TB) enhance the detrimental effects of both diseases in suffering individuals. The resistance mechanisms evolv-ing in Mycobacterium tuberculosis are limiting the efficiency of current therapeutic measures and pressurizing the stressed medical infrastructures. The bacterial efflux pumps enable the development of resistance against recently approved drugs such as bedaquiline and clofazimine. Conse-quently, the MmpS5-MmpL5 protein system was selected because of its role in efflux pumping of anti-TB drugs. The MmpS5-MmpL5 systems of Mycobacterium smegmatis were modelled and the virtual screening was performed using an ASINEX library of 5968 anti-bacterial compounds. The inhibitors with the highest binding affinities and QSAR based highest predicted inhibitory concen-tration were selected. The MmpS5-MmpL5 associated systems with BDE_26593610 and BDD_27860195 showed highest inhibitory parameters. These were subjected to 100 ns Molecular Dynamics simulations and provided the validation regarding the interaction studies. The in vitro studies demonstrated that the BDE_26593610 and BDD_27860195 can be considered as active inhib-itors for M. smegmatis MmpS5-MmpL5. The outcomes of this study can be utilized in other experi-mentation aimed at drug design and discovery against the drug resistance strains of M. tuberculosis. © 2022 by the authors. Licensee MDPI, Basel, Switzerland