112 research outputs found
Physicochemical investigation of anodic processes involved in silver electrowinning in refining technology
Электронно-микроскопические изменения слизистой оболочки носоглотки у пациентов с COVID-19 в зависимости от клинической формы и периода заболевания
Given that COVID-19 is a global public health problem and that almost all countries in the world have been severely affected by the COVID-19 pandemic, research is being actively pursued to better understand the effects of the virus on human cells. However, it is not clear what changes are observed in the cells of the main gate of infection – the mucosa of the mouth and the nose at different clinical forms and at different periods of disease. Understanding the ultra-structural cell changes of SARS-CoV-2 targets may help clarify the pathogenic aspects of infection in the lower respiratory tract. In this study, the elements of the life cycle of SARS-CoV-2 virus in the cells of the respiratory epithelium of the nose in patients with COVID-19 were evaluated using electron microscopy for the purpose of detecting the peculiarities of viral activity depending on the form and period of disease. Bioptats of the nasal mucous membrane were taken from COVID-19 patients and subsequently examined by electron microscopy. The severity of structural changes in tissue samples, presence of SARSCoV-2 virus in cells were determined, then bioptats were grouped according to the clinical form of the infection process (inapparent, acute upper respiratory tract infections, viral lung disease) and period of disease. It has been established that the most characteristic changes in the mucous membrane of the nose were observed in the first week of infection caused by SARS-CoV-2 and occurring in the form of acute respiratory disease, while viral lung infections have had the highest virus density in vesicles within cells, the formation of smooth virus-free vesicles is most common in inapparent forms. The data obtained may indicate that the formation of classical virus-induced changes in the respiratory epithelium of the nose mucous (vesicles with viral particles and signs of their release from the cell) is characteristic of localized forms of infection caused by SARS-CoV-2 (respiratory infection of the upper respiratory tract) and in cases of generalized infection (viral infection of the lungs and probably other organs and systems) accumulation of the infectious agent in high concentrations in vesicles. Учитывая, что COVID-19 представляет общемировую проблему в области здравоохранения и почти все страны мира серьезно пострадали от пандемии COVID-19, активно проводятся исследования, направленные на лучшее понимание воздействия вируса на клетки организма человека. Вместе с тем, не до конца ясно, какие изменения наблюдаются в клетках основных ворот инфекции – слизистой рото-, носоглотки при разных клинических формах и в разные периоды заболевания. Понимание ультраструктурных изменений клеток-мишеней SARS-CoV-2, возможно, поможет уточнить патогенетические аспекты распространения инфекции в нижние дыхательные пути. В настоящем исследовании при помощи электронной микроскопии проведена оценка элементов жизненного цикла вируса SARS-CoV-2 в клетках реснитчатого эпителия носоглотки у пациентов с COVID-19 с целью выявления особенностей жизнедеятельности вируса в зависимости от формы и периода заболевания. У больных COVID-19 отбирались биоптаты слизистой оболочки носоглотки, которые в последующем исследовались при помощи электронной микроскопии. Определялась выраженность структурных изменений в образцах ткани, наличие вируса SARS-CoV-2 в клетках, далее биоптаты были распределены по группам в зависимости от клинической формы инфекционного процесса (инаппарантная, острое респираторное заболевание верхних дыхательных путей, вирусное поражение легких) и периода заболевания. Установлено, что наиболее характерные изменения слизистой оболочки носоглотки наблюдались в 1-ю неделю инфекции, вызванной SARS-CoV-2 и протекающей в форме острого респираторного заболевания, тогда как для вирусного поражения легких отмечалась наибольшая плотность вируса в везикулах внутри клеток, при этом образование гладких везикул, не содержащих вируса, наиболее характерно для инаппарантных форм. Полученные данные могут свидетельствовать, что формирование классических вирус-индуцированных изменений реснитчатого эпителия слизистой носоглотки (везикул с вирусными частицами и признаками их выхода из клетки) характерно для локализованных форм инфекции, вызванной SARS-CoV-2 (респираторной инфекции верхних дыхательных путей), а в случаях развития генерализованной инфекции (вирусного поражения легких и, вероятно, других органов и систем) – накопление возбудителя в высоких концентрациях в везикулах.
Classical and Quantum Discrete Dynamical Systems
We study deterministic and quantum dynamics from a constructive "finite"
point of view, since the introduction of a continuum, or other actual
infinities in physics poses serious conceptual and technical difficulties,
without any need for these concepts to physics as an empirical science. For a
consistent description of the symmetries of dynamical systems at different
times and the symmetries of the various parts of such systems, we introduce
discrete analogs of the gauge connections. Gauge structures are particularly
important to describe the quantum behavior. We show that quantum behavior is
the result of a fundamental inability to trace the identity of
indistinguishable objects in the process of evolution. Information is available
only on invariant statements and values, relating to such objects. Using
mathematical arguments of a general nature we can show that any quantum
dynamics can be reduced to a sequence of permutations. Quantum interferences
occur in the invariant subspaces of permutation representations of symmetry
groups of dynamical systems. The observable values can be expressed in terms of
permutation invariants. We also show that for the description of quantum
phenomena, instead of a nonconstructive number system --- the field of complex
numbers, it is enough to use cyclotomic fields --- the minimal extentions of
natural numbers suitable for quantum mechanics. Finite groups of symmetries
play a central role in this article. The interest in such groups has an
additional motivation in physics. Numerous experiments and observations in
particle physics point to an important role of finite groups of relatively low
orders in a number of fundamental processes.Comment: author's English translation added; 74 pages in English, 80 pages in
Russian; English translation in Phys. Part. Nucl. ISSN 1063-7796 (2013) 44,
No. 1, pp 47-91 was done without author's control; V3: Section 4 revised; V4:
some correction
Determination of the resolving power of optical systems in the formation of speckle images
COMPARATIVE CHARACTERISTIC OF MEANS OF AUTOMATED CHECK OF THE CORRECTNESS OF WRITING OF SQL REQUESTS
The article presents an analysis of resources that can be used to test users who study the SQL language. Also, the article describes plan and result of the attack on web applications for learning the SQL language. There are some weaknesses of web applications in terms of their ability to verify the correctness of the compilation of SQL queries, which are also describes here. The conclusion deals with is made about the expediency of developing a specialized test system for verifying the correctness of writing SQL-queries
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