Nanometer Structured Epitaxial Films and Foliated Layers Based on Bismuth and Antimony Chalcogenides with Topological Surface States

The thermoelectric and galvanomagnetic properties of nanometer structured epitaxial films and foliated layers based on bismuth and antimony chalcogenides were investigated, and an increase in the figure of merit Z up to 3.85 × 10-3 K-1 was observed in the Bi0.5Sb1.5Te3 films over the temperature range of 180–200 K. It is shown that an increase in the Seebeck coefficient and the change in the slope on temperature, associated with changes in the effective scattering parameter of charge carriers and strong anisotropy of scattering in the films, lead to enhance power factor due to the growth of the effective mass of the density of states. These features are consistent with the results of research of oscillation effects in strong magnetic fields at low temperatures and research of Raman scattering at normal and high pressures in the foliated layers of solid solutions (Bi, Sb)2(Te, Se)3, in which the topological Dirac surface states were observed. The unique properties of topological surface states in the investigated films and layers make topological insulators promising material for innovation nanostructured thermoelectrics

Secretory phospholipase A2: a biomarker of inflammation in autoimmune, bacterial and viral diseases

Secretory phospholipases A2 (sPLA2) represent a large superfamily of enzymes with a molecular weight of 14-19 kDa, including 15 groups and more than 30 isoforms belonging to four types: secretory (sPLA2), cytosolic (cPLA2), calcium-independent (iPLA2) and lipoprotein-associated phospholipase A2 (LP-PLA2, PAF-AH). Eleven species of secretory sPLA2s (IB, IIA, IIC, IID, IIE, IIF, III, V, X, XIIA, and XIIB) have been found in mammals, performing versatile functions and participating in the pathogenesis of a wide range of diseases. On the one hand, sPLA2 may promote elimination of damaged, apoptotic cells by hydrolyzing membrane phospholipids, and exerts a strong bactericidal and antiviral properties, including pronounced effects against antibiotic-resistant strains of microorganisms. In this regard, the use of sPLA2 may represent a new strategy for the treatment of bacterial and viral infections. Moreover, due to the action of sPLA2 on its substrates, a number of biologically active molecules (arachidonic, lysophosphatidic acids, lysophospholipids, fatty acids, prostaglandins, leukotrienes, thromboxanes) are formed, which provide strong inflammatory, detergent, coagulating effects and increase vascular permeability. This pro-inflammatory role of sPLA2 may explain its increase levels and activity in cardiovascular, respiratory, autoimmune, metabolic, oncological, bacterial and viral disorders. The review article presents a classification of sPLA2 isoforms, their substrates, regulatory factors, biological significance, and mechanisms of their strong bactericidal, virucidal, and pro-inflammatory activity in the heart and lung disorders, autoimmune, metabolic, bacterial, and viral diseases. In particular, the mechanisms of the selective action of sPLA2 against Gram-positive and Gram-negative microorganisms are discussed. We consider diagnostic and prognostic significance, correlations between elevated levels and activity of sPLA2 and distinct clinical symptoms, severity and outcome in the patients with coronary heart disease (CAD), acute myocardial infarction (AMI), atherosclerosis, acute inflammatory lung injury (ALI), respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), rheumatoid arthritis, bronchial asthma, bacterial infections, septicemia and viral (COVID-19) infections. The opportunity of using sPLA2 as a biomarker of the severity and outcome of patients with chronic obstructive pulmonary disease, bacterial infections, sepsis and viral infections, including COVID-19, is also considered

Reversible metal-insulator transition of Ar-irradiated LaAlO₃/SrTiO₃ interfaces

The conducting state of a quasi-two-dimensional electron gas (q2DEG), formed at the heterointerface between the two wide-bandgap insulators LaAlO₃ (LAO) and SrTiO₃, can be made completely insulating by low-energy, 150-eV, Ar⁺ irradiation. The metallic behavior of the interface can be recovered by high-temperature oxygen annealing. The electrical transport properties of the recovered q2DEG are exactly the same as before the irradiation. Microstructural investigations confirm that the transition is not due to physical etching or crystal lattice distortion of the LAO film below its critical thickness. They also reveal a correlation between electrical state, LAO film surface amorphization, and argon ion implantation. The experimental results are in agreement with density functional theory calculations of Ar implantation and migration in the LAO film. This suggests that the metal-insulator transition may be caused by charge trapping in the defect amorphous layer created during the ion irradiation

Тезаурус по поэтологии как инструмент для информационного поиска и коллекции знаний

This paper reports basic approaches to constructive creation of an open resource named ”Domain-specified thesaurus of poetics”, which is one of the levels of an information-analytical system of the Russian poetry (IAS RP). The poetics is a group of disciplines focused on a comprehensive theoretical and historical study of poetry. IAS RP will be used as a tool for a wide range of studies allowing to determine the characteristic features of the analyzed works of poetry. Consequently, the thesaurus is the knowledge base from which one can borrow input data for training the system. The aim of our research requires a specific approach to formating the knowledge base. Thesaurus is a web-based resource which includes a domain-specific directory, information retrieval tools and tools for further analyzes. The study of glossary consisting of three thousand terms and a set of semantic fields is reviewed in this paper. Rdf-graph of the domain-specified thesaurus of poetics is presented, containing 9 types of objects and different kinds of relationships among them. Wiki-tecnologies are used for implementing a resource which allows to store data in Semantic Web formats.Рассмотрены основные подходы по конструктивному созданию открытого сетевого ресурса «Предметно-специфицированного тезауруса по поэтологии», который является одним из уровней информационно-аналитической системы русской поэзии (ИАС РП). Под поэтологией будем понимать группу дисциплин, ориентированную на всестороннее теоретическое и историческое изучение поэзии. ИАС РП будет использоваться в качестве инструмента для широкого спектра исследований, позволяющего определять характерные признаки анализируемых произведений поэзии. Таким образом, тезаурус соответствует базе знаний, из которой будут заимствоваться исходные данные для обучения системы. Описан подход по формированию базы знаний. Тезаурус представляет собой веб-ресурс, включающий предметно-ориентированный справочник, информационно-поисковый инструмент и инструмент для дальнейших анали- тических исследований. Детально рассмотрена проработка терминологического словника, состоящего из 3 тысяч терминов, и комплекса семантических полей. На основании этого представлен rdf-граф предметно-специфицированного тезауруса по поэтологии, содержащий 9 типов объектов и различные виды отношений между ними. Для реализации ресурса применяются Wiki-технологии, что дает возможность хранить данные в форматах Semantic Web