К ВОПРОСУ О МОДЕЛИРОВАНИИ ТУРБУЛЕНТНЫХ ТЕРМИЧЕСКИХ ПОТОКОВ

The main purpose of this work was the simulation of turbulent thermal flows, which is aimed at improving the visualization and the modeling of the flow fields of wind flows, which are necessary for aviation. The physical-mathematical model of gas flow in thermal is proposed on the basis of thermodynamic model and dynamic model under the assumption that the condensation energy, when the movement of the thermal is upward, becomes the turbulent fluctuations. A thermal is an air mass, which goes up and is capable to intermix with ambient air. In the work the thermodynamic model of thermal is presented, the equations and the system of equations are derived, that describe the main characteristics of wind flow, which are required for the modeling of airflows. The generation of vertical turbulent gust with von Karman spectrum is shown. The basic assumption in the construction of the dynamic model of generation was that the energy, which is stood out in the thermal due to the condensation of steam, is converted into the energy of turbulent pulsations. Some examples of numerical simulation are given in the article. The visualizations of the generation of the vertical velocity of random wind gust are given depending on the size of the considered space and depending on the pitch of cell partition. The analysis and comparison of the obtained results of the calculation are presented. The conducted studies are aimed at the simulation of the atmospheric background and atmospheric processes and, in the final result, at the increasing of flight safety.Основной целью работы являлось моделирование турбулентных термических потоков. На базе термодинамической и динамической моделей в предположении, что энергия конденсации пара при восходящем движении термического потока воздуха (термика) переходит в турбулентные пульсации, предложена физико-математическая модель течения газа в термике. В работе предложена система уравнений, описывающая восходящее течение воздуха. Предложена модель генерации вертикального турбулентного порыва с кармановским спектром. Основное предположение при построении динамической модели генерации заключалось в том, что выделившаяся в термике за счет конденсации пара энергия переходит в энергию турбулентных пульсаций. В статье приведены примеры численного моделирования. Визуализация вертикальной скорости случайного порыва ветра построена в зависимости от размера рассмотренного пространства и в зависимости от шага разбиения ячейки. Представлены анализ и сравнение полученных результатов расчета. Проведенные исследования направлены на моделирование атмосферного фона и атмосферных процессов и, в конечном результате, на повышение безопасности полетов

Susceptibility to SARS-CoV-2 Virus Variants of Concern in Mouse Models

The aim of the research was to assess the susceptibility of mice of different lines to newly emerging variants of SARS-CoV-2.Materials and methods. The SARS-CoV-2 virus strains belonging to variants of concern (VOC) circulating in the territory of the Russian Federation were used in the study. Experiments involved three inbred mouse lines (BALB/c, CBA and C57Bl/6z) and CD1 outbred mice taken from the nursery of the SSC VB “Vector” of the Rospotrebnadzor. The infectious titer of coronavirus in tissue samples obtained from the laboratory animals was determined on a Vero E6 cell culture. The (Ct) threshold value in RT-PCR was considered an additional parameter for monitoring the viral load in the samples. The severity of lung tissue damage was assessed using histological preparations.Results and discussion. The susceptibility of various mouse lines to the genetic variant Beta of the SARS-CoV-2 virus has been investigated. During intranasal infection of the inbred and outbred mice with strains of VOC at a dose of 2·103 TCID50, the virus replicated in the lungs with maximum concentrations 72 hours after infection. The pathogenicity of genetic variants of the SARS-CoV-2 virus for BALB/c mice has been assessed, a 50 % infectious dose for intranasal infection (ID50) determined. Histological analysis showed COVID-19-specific lung tissue lesions in infected animals. Our study proves that BALB/c mice can be used as a model animal in screening studies when evaluating the effectiveness of therapeutic, vaccine preparations and studying the pathogenesis caused by VOC of the SARS-CoV-2 virus: Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Omicron (B.1.1.529) and the like

Pathogenicity of the SARS-CoV-2 Virus Variants of Concern for the Syrian Golden Hamster

The aim of the work was to study the pathogenicity of newly emerging variants of SARS-CoV-2 on the model of the Syrian golden hamster.Materials and methods. We used the strains of SARS-CoV-2 virus related to the VOC circulating in the territory of the Russian Federation. The experiments were carried out on outbreed Syrian hamsters obtained from the nursery of the SSC VB “Vector”. The infectious titer of coronavirus in tissue samples collected from infected laboratory animals was determined on a Vero E6 cell culture. The Ct in RT-PCR was considered an additional parameter for monitoring the viral load in the samples. The severity of lung tissue damage in Syrian hamsters with COVID-19 was assessed by histological preparations.Results and discussion. 50 % infecting doses in case of the intranasal infection have been determined, histological analysis of lung tissues performed. The pathogenicity of various variants of the SARS-CoV-2 virus for the Syrian hamster has been evaluated, differences in infecting doses and pathological changes in the lungs have been revealed. SARS-CoV-2 viruses belonging to Beta genetic variant have the highest virulence, while Alpha variant has the lowest one when comparing the studied strains by the ID50 value. The Delta and Omicron variants have a matched ability to cause specific damage to the tissues of the respiratory tract, while being inferior only to the Beta variant. It has been demonstrated that Syrian hamsters are an adequate model for assessing the pathogenicity of the SARS-CoV-2 virus variants of concern. Variants of SARS-CoV-2 virus during intranasal infection has shown different degree of pathogenicity in the Syrian hamster model

TO THE QUESTION ABOUT THE SIMULATION OF TURBULENT THERMAL FLOWS

The main purpose of this work was the simulation of turbulent thermal flows, which is aimed at improving the visualization and the modeling of the flow fields of wind flows, which are necessary for aviation. The physical-mathematical model of gas flow in thermal is proposed on the basis of thermodynamic model and dynamic model under the assumption that the condensation energy, when the movement of the thermal is upward, becomes the turbulent fluctuations. A thermal is an air mass, which goes up and is capable to intermix with ambient air. In the work the thermodynamic model of thermal is presented, the equations and the system of equations are derived, that describe the main characteristics of wind flow, which are required for the modeling of airflows. The generation of vertical turbulent gust with von Karman spectrum is shown. The basic assumption in the construction of the dynamic model of generation was that the energy, which is stood out in the thermal due to the condensation of steam, is converted into the energy of turbulent pulsations. Some examples of numerical simulation are given in the article. The visualizations of the generation of the vertical velocity of random wind gust are given depending on the size of the considered space and depending on the pitch of cell partition. The analysis and comparison of the obtained results of the calculation are presented. The conducted studies are aimed at the simulation of the atmospheric background and atmospheric processes and, in the final result, at the increasing of flight safety

CULTIVATION AND CHARACTERISTICS OF MESENCHyMAL STEM CELLS FROM THE BONE MARROW OF THE PATIENTS WITH ORTHOPEDIC PATHOLOGY

The article presents data on the cultivation and characteristics of mesenchymal stem cells (MSC) isolated from the bone marrow of patients with dysplastic coxarthrosis. Several morphological phenotypes were found in the fraction of adhesive MSC: spindle-shaped elongated cells, large flattened cells, and thin stellate cells in both samples of bone marrow. Immunophenotypic analysis showed that cells express surface antigens (CD90, CD73, CD105, CD45 and CD34), which are characteristic for typical stem cells. It was shown that the use of a new growth medium containing no components of animal origin for the cultivation of human MSC allowed to achieve confluence of the cell culture on the 16th-8th day of incubation without delaying the proliferative activity of the cells and without loss of ability to differentiate into chondro- and osteogenic types of tissues. Multipotency of MSC was confirmed by osteogenic and chondrogenic differentiation of cells, during prolonged cultivation of MSCs in induction media in vitro . The differentiation of MSC into osteoblasts was confirmed by immunocytochemical staining for alkaline phosphatase and alizarin red S. Specific differentiation of MSC in chondrogenic type was revealed by staining of cartilage deposits with alcian blue. For the first time, such characteristics of human MSC as: mitotic index, trajectory of cells migration and average speed of migration on culture plastics were determined. The mitotic index of actively proliferating MSC was from 2.7 to 3.4 % of the total cell number. The moving activity (speed of cell migration) was 38-42 μm/h. Thus, bone marrow aspirate from patients with orthopedic pathology is the source of stem cells that meet all the criteria for MSC as determined by the International Society of Cellular Therapy and can be used in regenerative therapy of bone and cartilage

Confinement-deconfinement transition in dense SU(2) QCD

In this report we study the properties of the dense SU(2) QCD. The lattice simulations are carried out with improved gauge action and smaller lattice spacing as compared to our previous work. This allowed us to approach closer to the continuum limit and reach larger densities without lattice artifacts. We measured string tension and Polyakov loop as functions of chemical potential and temperature. At suffciently large baryon density and zero temperature we observe confinement/deconfinement transition which manifests itself as a vanishing of the string tension and rising of the Polyakov loop

Confinement-deconfinement transition in dense SU(2) QCD

In this report we study the properties of the dense SU(2) QCD. The lattice simulations are carried out with improved gauge action and smaller lattice spacing as compared to our previous work. This allowed us to approach closer to the continuum limit and reach larger densities without lattice artifacts. We measured string tension and Polyakov loop as functions of chemical potential and temperature. At suffciently large baryon density and zero temperature we observe confinement/deconfinement transition which manifests itself as a vanishing of the string tension and rising of the Polyakov loop