Hardness Descriptor Derived from Symbolic Regression

Hard and superhard materials play a vital role in numerous industrial applications necessary for sustainable development. However, discovering new materials with high hardness is challenging due to the complexity of this multiscale property and its and its intricate relationship with the atomic properties of the material. Here, we introduce a low-dimensional physical descriptor for Vickers hardness derived from a symbolic-regression artificial intelligence approach to data analysis. This descriptor is a mathematical combination of materials' properties that can be evaluated much more easily than hardness itself through the atomistic simulations, therefore suitable for a high-throughput screening. The artificial intelligence model was developed and trained using the experimental hardness values and high-throughput screening was performed on 635 compounds, including binary, ternary, and quaternary transition-metal borides, carbides, nitrides, carbonitrides, carboborides, and boronitrides to identify the optimal superhard material. The proposed descriptor is a physically interpretable analytic formula that provides insight into the multiscale relationship between atomic structure (micro) and hardness (macro). We discovered that hardness is proportional to the Voigt-averaged bulk modulus and inversely proportional to the Poisson's ratio and Reuss-averaged shear modulus. Results of high-throughput search suggest the enhancement of material hardness through mixing with harder, yet metastable structures (e.g., metastable VN, TaN, ReN$_2$, Cr$_3$N$_4$, and ZrB$_6$, all of them exhibit high hardness)

АNALYSIS OF THE EXPRESSION LEVEL OF T-CELL GENES AND OXIDATIVE PROCESSES IN STROKE

The level of expression of genes of transcription factors (GATA-3, TBX21, IL-2PG), and changing  of oxidative processes in ischemic stroke were studied.It was found that activation of Th2 cells (increase in the expression of transcription factor GATA-3) is observed in stroke,   and suppression of Th1 cells (a decrease in the expression of IL-2 and its receptors, as well as the TBX21 gene).  Increasing the expression of transcription factor GATA-3 in stroke patients underlies the increase in production in these patients of Th2-cytokines.    A comparative analysis of protein oxidation in blood plasma revealed an increase in the intensity of oxidative modification of proteins in stroke patients.  Investigation of glutathione content, activity of glutathione peroxidase enzymes, glutathione reductase in erythrocytes in stroke revealed a decrease in the content of glutathione and glutathione reductase and an increase in the activity of glutathione peroxidase.The findings may be useful for a better understanding of the mechanisms of stroke

Insulation Systems of Frame Cottages

• The article presents studies of the exploitation characteristics of the material, the results of a full-scale survey of a residential private house insulated with expanded polyethylene, as well as the main design solutions for the insulation of a frame cottage. The features of insulation systems of low-rise buildings, including those with a frame-bearing carrier system, are considered. It has been substantiated that the use as thermal insulation of mineral-wool plates used on non-loaded structures assumes the mandatory placement of vapor barrier (usually plastic film) from the inside of the insulated surface and the windproof membrane outside. The use of a rolled foamed polyethylene as an insulating material makes it possible to realize an insulating sheath without additional layers. Experimental determinations of diffusion moisture absorption, water absorption upon partial immersion in water, water absorption upon full immersion in water, tensile strength in the longitudinal direction, and adhesion strength of the adhesive layer to metal were performed. It was established that the diffusion moisture absorption of samples of expanded polyethylene is 0.51-0.75%, and taking into account the weld it is 0.70-0.75%. Water absorption of samples when fully immersed in water does not exceed 0.96% by volume. The tensile strength in the longitudinal direction for products with a metallized coating is 80-92 kPa, without a metallized coating - 80-87 kPa, and for a weld - 29-32 kPa. A field survey showed that the humidity of the pine timber is within the normative. The expediency of warming only the outer coating of expanded polyethylene of the calculated thickness without filling the frame is justified, which, with standard air exchange and observance of the conditioning conditions, will be sufficient to maintain the microclimate in the room

Multidrug-resistance and presence of class 1 integrons in clinical isolates of Salmonella enterica serotype Enteritidis, circulating in Armenia

Abstract. The aim of this work was detection of class 1 integrons and their contribution to the antimicrobial resistance phenotypes in strains of   subspecies enterica serotype Enteritidis. S. Enteritidis strains (n = 29) were isolated from patients with salmonellosis at “Nork” Clinical Hospital of Infectious Diseases, Yerevan, Republic of Armenia. High prevalence of multi-drug resistance (MDR) phenotypes was revealed and isolates with MDR phenotypes which are rare in the S. Enteritidis serotype were observed. Class 1 integrons were detected in 27,6% of isolates, with the prevalence of a variable region of 1000 bp. Occurrence of the MDR phenotype was more frequent in integron-positive isolates compared to integron-negative isolates of S. Enteritidis. Further studies are necessary to reveal the genetic background of MDR phenotypes and to estimate the genetic kinship among the isolates. Our results suggest a rapid and large-scale penetration of antibiotic resistance genes into populations of S. Enteritidis, which complicates infection control. More rigorous regulations should be imposed on antibiotic use, together with a vigilant epidemiological surveillance, to prevent the emergence and spread of MDR S. Enteritidis

ПРОФИЛАКТИКА ХИРУРГИЧЕСКИХ ОСЛОЖНЕНИЙ, СВЯЗАННЫХ С МЕТОДИКОЙ АЛЬВЕОЛЯРНОЙ МЕЖКОМПАКТНОЙ ОСТЕОТОМИИ

The article examines possible medical errors during the interalveolar osteotomy that may negatively affect the effectiveness of the treatment. It also analyses the basic techniques that provide adequate vitality of the tissues in the place of surgery. It also demonstrates the necessity of the reconstruction of the full thickness of the gum in order to achieve long-term esthetic results in the area of dental implantation.Рассмотрены возможные врачебные ошибки при проведении альвеолярной межкомпактной остеотомии, отрицательно сказывающиеся на эффективности проводимого лечения. Помимо этого, проанализированы основные приемы, обеспечивающие адекватную жизнеспособность тканей в зоне хирургического вмешательства. Обоснована необходимость воссоздания полноценной толщины десны с целью достижения долгосрочных эстетических результатов в зоне дентальной имплантации

Fabrication of Cu-W Nanocomposites by Integration of Self-Propagating High-Temperature Synthesis and Hot Explosive Consolidation Technologies

Manufacturing W-Cu composite nanopowders was performed via joint reduction of CuO and WO3 oxides with various ratios (W:Cu = 2:1, 1:1, 1:3, 1:13.5) using combined Mg–C reducer. Combustion synthesis was used to synthesize homogeneous composite powders of W-Cu and hot explosive consolidation (HEC) technique was utilized to fabricate dense compacts from ultrafine structured W-Cu powders. Compact samples obtained from nanometer sized SHS powders demonstrated weak relation between the susceptibility and the applied magnetic field in comparison with the W and Cu containing micrometer grain size of metals. The density, microstructural uniformity and mechanical properties of SHS&HEC prepared samples were also evaluated. Internal friction (Q-1) and Young modulus (E) of fabricated composites studied for all samples indicated that the temperature 1000 °С is optimal for full annealing of microscopic defects of structure and internal stresses. Improved characteristics for Young modulus and internal friction were obtained for the W:Cu = 1:13.5 composite. According to microhardness measurement results, W-Cu nanopowders obtained by SHS method and compacted by HEC technology were characterized by enhanced (up to 85%) microhardness

Development of a Reagent for Evaluation of Incipient Immune Response to the Live Plague Vaccine

Objective of the study is to develop a reagent for the detection of lymphocytes with Yersinia pestis F1 antigen receptors. Materials and methods. Utilized have been: live plague vaccine based on the strain of Yersinia pestis EV NIIEG, formalin killed suspensions of microorganisms - Y. pestis , 3123, Y. enterocolitica O9 H-383 serovar, Y. pseudotuberculosis O1 2841 serovar; acetaldehyde-immobilized capsular antigen of Y. pestis F1 (obtained applying Baker methodology), lipopolysaccharide of Y. pestis K1, and bovine erythrocytes. Bovine erythrocyte F1 sensibilization has been performed using rivanol. Lymphocytes from blood have been isolated in density gradient ficoll-verografin 1.077. Lymphocytes with Yersinia pestis F1 antigen receptors have been detected by means of reagent adhesion onto the isolated lymphocytes. F1-free erythrocytes serve as controls. After the exposition, 7 evaluations of specificity to F1 and the lymphocytes, binding control reagent, have been carried out. Deployed have been 8 rabbits, immunized with live vaccine EV, and 2 rabbits, immunized with inactivated vaccine EV. Examined have been EV-vaccinated 5 persons. Results and conclusions. Identified is optimum sensibilizing dose of F1 antigen (250 µg/ml). Specificity of lymphocytes with receptors to F1 is demonstrated in inhibition experiments applying homologous and heterogeneous antigens. Lymphocytes with receptors to F1 (LRs) have been detected in peripheral blood of all rabbits and humans, immunized with vaccine EV. LRs have been registered since day 2 till day 35 in the rabbits, and in humans - since day 2 till day 14 after vaccination. It is shown that in case of revaccination of humans, LRs emerge and disappear earlier, than in case of primary immunization

The impact of formative testing on study behaviour and study performance of (bio)medical students: a smartphone application intervention study.

BACKGROUND: Formative testing can increase knowledge retention but students often underuse available opportunities. Applying modern technology to make the formative tests more attractive for students could enhance the implementation of formative testing as a learning tool. This study aimed to determine whether formative testing using an internet-based application ("app") can positively affect study behaviour as well as study performance of (bio)medical students. METHODS: A formative testing app "Physiomics, to the next level" was introduced during a 4-week course to a large cohort (n = 461) of Dutch first year (bio)medical students of the Radboud University. The app invited students to complete 7 formative tests throughout the course. Each module was available for 3-4 days to stimulate the students to distribute their study activities throughout the 4-week course. RESULTS: 72% of the students used the app during the course. Study time significantly increased in intensive users (p < 0.001), while no changes were observed in moderate (p = 0.07) and non-users (p = 0.25). App-users obtained significantly higher grades during the final exam of the course (p < 0.05). Non-users more frequently failed their final exam (34%, OR 3.6, 95% CI: 2.0-6.4) compared to moderate users (19%) and intensive users (12%). Students with an average grade <6.5 during previous courses benefitted most from the app, as intensive (5.8 ± 0.9 / 36%) and moderate users (5.8 ± 0.9 / 33%) obtained higher grades and failed their exam less frequently compared to non-users (5.2 ± 1.1 / 61%). The app was also well appreciated by students; students scored the app with a grade of 7.3 ± 1.0 out of 10 and 59% of the students indicated that they would like the app to be implemented in future courses. CONCLUSIONS: A smartphone-based application of formative testing is an effective and attractive intervention to stimulate study behaviour and improve study performance in (bio) medical students

Ewing Sarcoma Protein Ewsr1 Maintains Mitotic Integrity and Proneural Cell Survival in the Zebrafish Embryo

BACKGROUND:The Ewing sarcoma breakpoint region 1 gene (EWSR1), also known as EWS, is fused to a number of different partner genes as a result of chromosomal translocation in diverse sarcomas. Despite the involvement of EWSR1 in these diverse sarcomas, the in vivo function of wild type EWSR1 remains unclear. PRINCIPAL FINDINGS:We identified two zebrafish EWSR1 orthologues, ewsr1a and ewsr1b, and demonstrate that both genes are expressed maternally, and are expressed ubiquitously throughout zebrafish embryonic development. Morpholino induced knockdown of both zebrafish ewsr1 genes led to mitotic defects with multipolar or otherwise abnormal mitotic spindles starting from the bud stage (10 hour post-fertilization (hpf)). The abnormalities in mitotic spindles were followed by p53-mediated apoptosis in the developing central nervous system (CNS) leading to a reduction in the number of proneural cells, disorganization of neuronal networks, and embryonic lethality by 5 days post-fertilization. siRNA silencing of EWSR1 in Hela cells resulted in mitotic defects accompanied by apoptotic cell death, indicating that the role of EWSR1 is conserved between zebrafish and human. CONCLUSIONS:Ewsr1 maintains mitotic integrity and proneural cell survival in early zebrafish development

НАУЧНЫЙ ПРАКТИКУМ ДЛЯ СТУДЕНТОВ ПО СПЕЦИАЛЬНОСТИ «МЕДИЦИНСКАЯ БИОФИЗИКА»

This article focuses on specialized scientific Practicum organized on April 14s 2016 by the Laboratory of biophysics of cells membranes in critical illness of V. A. Negovsky Research Institute of General Reanimatology for students enrolled in the specialty «Medical Biophysics» at the I. M. Sechenov First Moscow State Medical University. During the study students had mastered a number of techniques: atomic force microscopy, calibrated electroporation, spectrophotometry. Students familiarized with the methodology of scientific experiment and mathematical treatment of the results.Статья посвящена специализированному научному практикуму, организованному на базе лаборатории «Биофизики мембран клеток при критических состояниях» НИИ общей реаниматологи им. В. А. Неговского для студентов, обучающихся по специальности «Медицинская биофизика» в Первом МГМУ им. И. М. Сеченова. В ходе работы студентами был освоен ряд методик: атомная силовая микроскопия, калиброванная электропорация, спектрофотометрия. Студенты ознакомились с методологией научного эксперимента и математической обработкой полученных результатов