Theoretical backgrounds of nonlinear THz spectroscopy of semiconductor superlattices

We consider terahertz absorption and gain in a single miniband of semiconductor superlattice subject to a bichromatic electric field in the most general case of commensurate frequencies of the probe and pump fields. Using an exact solution of Boltzmann transport equation, we show that in the small-signal limit the formulas for absorption always contain two distinct terms related to the parametric and incoherent interactions of miniband electrons with the alternating pump field. It provides a theoretical background for a control of THz gain without switching to the negative differential conductivity state. For pedagogical reasons we present derivations of formulas in detail.Comment: 14 page

Organization and management of clusters in Russia in the context of import substitution

The article covers the trends of the agribusiness development in Russia. It is shown that it is desirable to develop organizational-economic forms of entrepreneurship based on the cluster approach in the modern realities. The most famous agribusiness clusters in the world are explored. Regions of Russia that have achieved the most significant results in agribusiness clustering are mentioned. It is found that the establishment of agribusiness in Russia is defined by the political decision of regional authorities rather than based on research and development. An algorithm for establishing the agribusiness cluster is proposed, which includes four stages: methodological, analytical, organizational-economic and control. The key areas of state support for the development of agribusiness clusters in Russia are defined.peer-reviewe

Nonequilibrium phenomena in high Landau levels

Developments in the physics of 2D electron systems during the last decade have revealed a new class of nonequilibrium phenomena in the presence of a moderately strong magnetic field. The hallmark of these phenomena is magnetoresistance oscillations generated by the external forces that drive the electron system out of equilibrium. The rich set of dramatic phenomena of this kind, discovered in high mobility semiconductor nanostructures, includes, in particular, microwave radiation-induced resistance oscillations and zero-resistance states, as well as Hall field-induced resistance oscillations and associated zero-differential resistance states. We review the experimental manifestations of these phenomena and the unified theoretical framework for describing them in terms of a quantum kinetic equation. The survey contains also a thorough discussion of the magnetotransport properties of 2D electrons in the linear response regime, as well as an outlook on future directions, including related nonequilibrium phenomena in other 2D electron systems.Comment: 60 pages, 41 figure

The Role of Outer Membrane Vesicles of Agents of Particularly Dangerous Infections in the Pathogenesis and Immunogenesis of Infectious Process

The literature review is devoted to the modern concepts of the vesiculation phenomenon and its biological role in pathogenic bacteria – causative agents of particularly dangerous human infections. Data on the production, structure, composition, and functions of the outer membrane vesicles (OMV) of bacteria have been summarized. In recent years, the interest of researchers in the formation of spherical structures (so called bubbles or vesicles) from outer membrane of gram-negative bacteria has significantly increased. Such structures are surrounded by the double layer of a phospholipid membrane, the outer layer of which is enriched with lipopolysaccharide molecules. The inner space of vesicles could include various antigens, receptors, adhesins, toxins, enzymes, porins, etc. The formation of vesicles by the outer membranes of bacteria is recognized as a normal physiological manifestation of bacterial activity aimed at adaptation to environmental conditions. The investigation of the biological role of OMV showed their connection with the pathogenesis and immunogenesis of bacterial diseases. The review provides information on the peculiarity of induction, OMV composition and their participation in the processes of patho- and immunogenesis of severe infections caused by groups I–II PBA – the gram-negative causative agents of plague, tularemia, brucellosis, glanders, melioidosis, cholera, and formation of extracellular vesicles in a gram-positive anthrax pathogen. The particular attention is paid to the issue of developing safe and effective next-generation vaccine preparations based on bacterial vesicles

Recurrent vulvovaginal candidiasis during COVID-19 pandemic: medical algorithm

The review article presents data on the prevalence of candidiasis of various localization against the history of coronavirus infection (COVID-19). The predisposing factors for the development and recurrence of candidiasis in patients after therapy for coronavirus infection have been analysed. Candida is one of the most common pathogens in intensive care units (ICUs), affecting 6 to 10% of patients, and some studies have reported an increasing trend in the prevalence of candidemia. The literature data that we analysed showed that the most common types of fungal infection among patients with a severe course of COVID-19 were C. albicans, then C. auris, C. glabrata, C. parapsilosis, C. tropicalis, S. cerevisiae, C. krusei and Rhodotorula spp. Candida non-albicans species, in particular C. glabrata, C. auris, were the most common causes of death. The previous treatment regimens for patients with COVID-19 included antibiotics, but at present time corticosteroids are more often used, which have an immunosuppressive effect and, accordingly, predispose to the development of candidiasis. The epithelial injury caused by SARS-CoV-2 also enables Candida to attach to the basement membrane, subsequently triggering the development of mucosal candidiasis. As the systemic and local candidiasis are conditioned by common immune mechanisms that are affected by coronavirus infection, vulvovaginal candidiasis (VVC) may recur during COVID-19 therapy. The timely diagnosis and treatment of fungal infections in patients who underwent COVID-19 are crucial for achieving a positive clinical outcome. The article provides an algorithm for the management of patients with recurrent VVC, the principles of action of antifungal drugs, their acceptability and efficacy

Influence of boric anhydride upon the physical and chemical properties of ferrosilicon slag

The authors study the influence of boric anhydride upon the physical and chemical properties of slag in the manufacture of ferrosilicon. It is established that adding boric anhydride to the slag changes its refractory quality and its viscosity and eases pouring slag and metal. Slags with optimal composition and properties are described

Comparative Molecular-Genetic Analysis of <i>Francisella tularensis</i> Strains Isolated in the Rostov Region in 2020 and Genome Sequences of the Strains Collected in Various Regions of the World

Six cultures of tularemia microbe from fallen and captured live animals were isolated during epizootiological monitoring in the steppe focus in the south-east of the Rostov Region in 2020 against the background of extensive epizootics in the populations of the common vole Microtus arvalis obscurus and the public vole Microtus socialis.The aim of the work was to develop an SNP-typing scheme and to conduct a comparative study of the phylogenetic relations between Francisella tularensis strains isolated in the Rostov Region (2020) and strains from other regions.Materials and methods. Genome-wide sequencing was performed on the MiSeq Illumina platform. The author’s software GeneExpert, PrimerM and VirtualPCR, written in the Java programming language, were used for the analysis.Results and discussion. The strains of tularemia agent, isolated on the territory of the Rostov Region in 2020, can be allocated to two different clusters. It is established that two strains of tularemia pathogen (F0884 and F0889) isolated in Turkey are genetically close to some isolates circulating in the Rostov Region. A unique INDEL marker characteristic of this group of strains has been identified. The comparison of our proposed typing scheme with the scheme of “canonical” SNPs has showed a fairly good consistency and convergence of results within large clusters, meanwhile using a set of 6626 SNPs allows for differentiating the strains within one canSNP type. It is revealed that the vaccine strain has a common canSNP type with clinical and natural strains. A set of SNP markers has been selected for comparative analysis. A new INDEL marker that enables intraspecific typing of F. tularensis has been discovered and the possibility of its application in vitro and in silico has been comfirmed

A Line Through the Sacred Lands of the Altai Mountains: Perspectives on the Altai Pipeline Project

In 2006 preliminary plans were made public showing that Gazprom intended to construct a pipeline through the Altai republic (Russia, south-west Siberia). Unfortunately, there was almost no attention to integrating the conservation of cultural heritage (both archaeological and landscape) into the planning of the pipeline, though the Altai is well-known for its rich cultural heritage. Hitherto, no assessment has been made of the potential impact of the project, nor did Gazprom release detailed information about the exact course of the route. The present article aims to illustrate the potential impact of the pipeline based on a detailed study of a small segment of the route, using remote sensing images and data gathered during fieldwork. This assessment underlines the need for a well-thought-out strategy, which is required if sustainable integration of heritage conservation into the construction plan is to be realized. If such a balance is not found, thousands of archaeological monuments could disappear, which would result in a huge cultural and scientific loss. As a possible solution, an integrative strategy founded on a desk-based study of remote sensing images and a well-directed field survey is suggested

КОКЛЮШ У ДЕТЕЙ ПЕРВОГО ГОДА ЖИЗНИ

We observed 209 children the first year of life, admitted to inpatient treatment with a diagnosis of whooping cough (pertussis). In 41 patients there was the need for mechanical ventilation in treatment. Presents a number of ventilator parameters and sequence of their use in whooping cough in the event of prolonged apnea. The need for vaccinoprophylaxis of pertussis is grounded.Под наблюдением находилось 209 детей первого года жизни, поступивших на стационарное лечение с диагнозом коклюш. По показаниям у 41 пациента в комплексном лечении применялась ИВЛ. Представлен ряд параметров ИВЛ и последовательность их использования при коклюше в случае развития продолжительных апноэ. Обоснована необходимость вакцинопрофилактики коклюша