Letter to the editor. Discussion of the article by A.A. Zarubin, E.S. Filippov, A.S. Vanyarkina, O.G. Ivanova, A.A. Shishkina “Comparison of Uncontrolled and Device-Induced Therapeutic Hypothermia in Newborn Infants with Hypoxic Ischemic Encephalopathy”, published in Acta biomedica scientifica. 2021; 6(1): 88-93. doi: 10.29413/ABS.2021-6.1.13

The article presents a discussion of the study results of the effectiveness of treatment of newborns infants with hypoxic ischemic encephalopathy using device-induced therapeutic hypothermia which were obtained by a group of researchers (Zarubin A.A. et al.) in comparison with the results of Russian and foreign researchers

Public-private partnership in in the information and telecommunication technologies sector: relationship with macro- and meso- indicators

The article substantiates the importance of stimulating the information and telecommunication technologies development for the economy and considers the experience of using public-private partnership tool for investment in the IT technologies field in Russia and abroad. Conclusions about the specifics and dynamics of implementation of these projects in developing countries of the world have been made. Using regression analysis, the macroeconomic factors influencing the investments volume in the information and telecommunication technologies sector through public-private partnership tool have been identified and, based on a sample of developing countries, the specific sectoral determinants influence on public-private partnership activity has been studied. The conclusions formulated in the article can serve as a practical guide for private investors and government authorities when launching public-private partnership-projects in the information and telecommunication technologies sector

DESIGNING OF DEVELOPED SURFACES OF COMPLEX PARTS

Purpose. The paper focuses on ensuring the rational choice of parameters of the mating surfaces of parts when designing process equipment based on the methods of artificial intelligence. Methodology. The paper considers the geometric model of a ruled developed surface, the conditions of existence of such a surface and provides a generalized algorithm for surface plotting regardless of the type of the working element or the machine-building product. One of the most common technical surfaces are the ruled ones, among which a special position is occupied by developed surfaces (thanks to their differential-parametric properties): surface tangent plane is n contact along the rectilinear generator and does not change its position in space when changing the point of contact; surfaces can be produced by bending sheet metal. These provisions enable a product manufacturer to save significant material and energy means, therefore, the development of geometric models of such surfaces is an important task. Findings. We analyzed the geometrical model of the developed surface which is incident to two guides. Experimental studies have shown the applicationprospectivity of semi-digger moldboards on moldboard plows, particularly on the double-deck ones. Taking into account the operating speed of the plow 2.8 m/s, the plant residues plowing percentage for plow with semi-digger moldboards is 98.9%, and with the digger ones – 96.1%. Originality. According to results: 1) the approaches to solving the problem of recognition of wear conditions of the tested interface, depicted by its conceptual model, were elaborated; 2) the corresponding algorithms of the computational procedures were built; 3) the mathematical model that determines the effect of the parameters of the contacting surfaces on their performance properties – linear wear rate during the normal wear and tear was developed; 4) for this model the theoretical prerequisite of use for the random mating study were designated. Practical value. Currently, these areas produced significant results which are in line with modern requirements of construction engineering. The process of parametric model optimization generates a plurality of desired values of the surface parameters. There are formed the algorithms for automatic recognition of design features and operation of interfaces by their images, which are set by a structured set of formal signs. The recognition result is the interface designation to a particular group, each of which corresponds to an individual computational model of quality parameters normalization

Electroanatomic substrate of atrial fibrillation in patients after COVID-19

Aim. To determine the features of left atrial electroanatomic structure and the arrhythmia substrate in patients with atrial fibrillation (AF) after coronavirus disease 2019 (COVID-19).Material and methods. The pilot study included 20 patients with AF who underwent catheter radiofrequency ablation. Ten patients had COVID-19 and 10 patients were included as a control group. AF substrate was identified using anatomic and bipolar mapping. Zones with following amplitudes were analyzed: <0,25 mV, <0,5 mV, from 0,5 to 0,75 mV inclusive, and >0,75 mV. Left atrial volume was determined based on anatomic map.Results. The groups were homogeneous in AF type, number of patients after prior pulmonary vein isolation, and heart rate during mapping. In the COVID-19 group, there was a higher area of fibrous zones with an amplitude of <0,25 mV (51,5±16,6% vs 29,1±16,1% in the control group, p=0,007), <0,5 mV (76,7±11,5% vs 45,6±22,7% in the control group, p=0,001) and a lower area of intact myocardium with an amplitude >0,75 mV (11,6±8,0% vs 45,0±25,0% in the control group, p=0,001). In 7 COVID-19 patients, the posterior wall was isolated due to low-amplitude zones. Of these, three patients underwent surgery for the first time. According to ROC analysis, in patients after COVID-19, fibrous tissue (<0,5 mV) occupies more than half of the area, while normal tissue (>0,75 mV) — ~30% or less.Conclusion. This study shows that SARS-CoV-2 infection may cause left atrial remodeling in the form of diffuse fibrosis. The arrhythmia substrate in patients after COVID-19 can be localized not only in pulmonary vein mouths, but also in other left atrial areas. This must be taken into account before ablation, even if the procedure is being performed for the first time. It is recommended to perform amplitude mapping for all patients who have had SARS-CoV-2 infection in order to identify fibrous zones and plan the operation extent

АНАЛИЗ РАБОТЫ КОМБИНИРОВАННОГО АКТИВНОГО ФИЛЬТРА ПОСЛЕДОВАТЕЛЬНОГО ТИПА С СЕЛЕКТИВНЫМИ ЗВЕНЬЯМИ ДЛЯ ТЯГОВОЙ ПОДСТАНЦИИ ПОСТОЯННОГО ТОКА

The results of the studies of the combined active filter of a sequential type with a continuous control system for direct current traction substation traction are presented. In the structure under consideration the aperiodic passive LC-filter operates in conjunction with the active one, the operation principle of the latter is being based on the formation of the channel feedback system of automatic voltage regulation of compensation of the variable component of the output voltage of the substation. The structure of a control system of a combined active filter of the series type has been proposed, which specific feature is the use of two parallel running circuits of feedback. The first one generates a signal for compensation of the variable component in a wide range of frequencies. The second one is built with the use of selective links that are configured to low frequency, including the non-canonical harmonic voltage with large amplitude. As a result of analytical studies the expression of the transfer function of the control system of the active filter of the series type with selective link has been obtained. The logarithmic amplitude-frequency characteristics of the combined active filter with and without selective link that had been determined clearly demonstrated the higher efficiency of suppression of the non-canonical harmonics in the second case. In order to confirm the reliability of the analytical results of the control system of the active filter a simulation model in MatLab has been developed. The analysis of the combined active filter of the series type with selective links demonstrated that its use is expedient for quality improvement of the supply the electric rolling stock with direct current energy, also achieving the desired level of electromagnetic compatibility of traction network with systems of railway automatics and communications.Приведены результаты исследований комбинированного активного фильтра последовательного типа с непрерывной системой управления для тяговых подстанций постоянного тока. В рассматриваемой структуре пассивный апериодический LC-фильтр работает совместно с активным, принцип действия которого основан на формировании по каналу обратной связи системы автоматического регулирования напряжения компенсации переменной составляющей выходного напряжения подстанции. Предложена структура системы управления комбинированного активного фильтра последовательного типа, особенностью которой является использование двух параллельно работающих цепей обратной связи. Первая формирует сигнал для компенсации переменной составляющей в широком диапазоне частот. Вторая построена с применением селективных звеньев, которые настроены на низкочастотные, в том числе неканонические, гармоники напряжения с большими амплитудами. В результате аналитических исследований получено выражение передаточной функции системы управления активного фильтра последовательного типа с селективным звеном. Построенные логарифмические амплитудно-частотные характеристики комбинированного активного фильтра без селективного звена и с ним наглядно показали более высокую эффективность подавления неканонических гармоник во втором случае. Для подтверждения достоверности результатов аналитических исследований системы управления активного фильтра разработана его имитационная модель в среде MatLab. Проведенный анализ комбинированного активного фильтра последовательного типа с селективными звеньями показал, что его применение целесообразно на тяговой подстанции для улучшения качества питающей электрический подвижной состав энергии постоянного тока, при этом также достигается необходимый уровень электромагнитной совместимости тяговой сети с системами железнодорожной автоматики и связи

Graphs and Reflection Groups

It is shown that graphs that generalize the ADE Dynkin diagrams and have appeared in various contexts of two-dimensional field theory may be regarded in a natural way as encoding the geometry of a root system. After recalling what are the conditions satisfied by these graphs, we define a bilinear form on a root system in terms of the adjacency matrices of these graphs and undertake the study of the group generated by the reflections in the hyperplanes orthogonal to these roots. Some ``non integrally laced " graphs are shown to be associated with subgroups of these reflection groups. The empirical relevance of these graphs in the classification of conformal field theories or in the construction of integrable lattice models is recalled, and the connections with recent developments in the context of ${\cal N}=2$ supersymmetric theories and topological field theories are discussed.Comment: 42 pages TEX file, harvmac and epsf macros, AMS fonts optional, uuencoded, 8 figures include

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

Оценка in vitro адсорбционных свойств различных устройств для селективной гемосорбции липополисахарида (экспериментальное исследование)

The objective: to study in vitro adsorption properties of various devices for selective lipopolysaccharide (LPS) adsorption.Subjects and Methods: Various methods of closed circuit circulating bovine serum endotoxin solutions were used. The serum was perfused using an LPS sorption device for 240 min. Serum samples were collected before the start of perfusion, and 30, 60, 120, 150, and 240 minutes after the start of circulation. LPS concentrations were measured by the turbidimetric method. One column for polymyxin hemoperfusion and three devices for selective adsorption of lipopolysaccharides were assessed.Results: When using the device for polymyxin hemoperfusion, the concentration of endotoxin in bovine serum decreased by 61% during 120 minutes, and in 120 minutes after additional administration of endotoxin, it went down by 57%. When using the other three devices, these parameters made 9% and 6%, 10% and 8%, 5% and 10%, respectively. Conclusion. By definition, an in vitro study cannot provide for complex pathophysiological reactions occurring in the body during sepsis. Тhis fact leads to limitations in extrapolating the results obtained to clinical practice.Цель исследования: изучить in vitro адсорбционные возможности различных устройств для селективной гемосорбции липополисахарида (ЛПС).Методы. Использовали методики циркуляции раствора эндотоксина в бычьей сыворотке в замкнутом контуре. Сыворотка перфузировалась через устройство для ЛПС-сорбции в течение 240 мин. Образцы сыворотки собирали до начала перфузии, через 30, 60, 120, 150 и 240 мин после начала циркуляции. Концентрации ЛПС измеряли турбидиметрическим методом. Изучали одну колонку для проведения полимиксиновой гемоперфузии и трех устройств для выполнения селективной адсорбции ЛПС.Результаты: при применении колонки для проведения полимиксиновой гемоперфузии степень снижения концентрации эндотоксина в бычьей сыворотке в течение 120 мин составила 61%, через 120 мин после дополнительного введения эндотоксина – 57%. При использовании остальных трех устройств данные показатели составили 9 и 6%, 10 и 8%, 5 и 10% соответственно.Вывод. Исследование in vitro по определению не может предусмотреть сложный комплекс патофизиологических реакций, протекающих в организме при сепсисе, что обусловливает ограничения в экстраполировании полученных результатов на клиническую практику

Создание трансгенных растений салата, содержащих ген сшитого белка антигенов ESAT6:Ag85B из Mycobacterium tuberculosis

Трансгенні рослини є багатообіцяючим і безпечним інструментом для створення їстівних вакцин. Імунізація, що відбувається внаслідок вживання в їжу рослин, у яких проходить експресія туберкульозних антигенів, є перспективним підходом у боротьбі з туберкульозом. У цій роботі ми повідомляємо про створення трансгенних рослин салату (Lactuca sativa), що містять ген зшитого білка антигенів Mycobacterium tuberculosis ESAT6:Ag85B. Трансгенні рослини були отримані методом трансформації за допомогою Agrobacterium tumefaciens. У роботі були використані вектори, що містять ген esxA, зшитий з геном fbpB. Також вектори містили селективні гени: ген неоміцинфосфотрансферази (nptII) або фосфінотрицин ацетилтрансферази (bar). На селективному середовищі були відібрані трансгенні рослини салату. Наявність селективного та цільового генів у геномі цих рослин була підтверджена за допомогою ПЛР. Трансгенні рослини салату були висаджені в ґрунт в умовах теплиці для проведення наступних досліджень.Transgenic plants are promising and potentially safe tools to produce edible vaccines. Passive immunization by oral delivery of Mycobacterium tuberculosis antigens expressed in transgenic plants seems to be the perspective strategy to combat tuberculosis. In this paper, we discuss the generation of lettuce (Lactuca sativa) transgenic plants carrying the fused gene of Mycobacterium tuberculosis antigens ESAT6:Ag85B. By employing Agrobacterium mediated transformation method, transgenic plants are obtained. Vectors containing gene esxA fused with fbpB gene are used. Plasmid vectors also contain selective genes of neomycin phosphotransferase II (nptII) or phosphinothricin acetyl transferase (bar). Stable transgenic plants are selected. By using PCR analysis, we confirm the presence of target and selective genes in plants genome. Rooted plats are transferred to soil in the greenhouse for further experiments.Трансгенные растения являются многообещающим и безопасным инструментом для создания съедобных вакцин. Иммунизация, что происходит в результате употребления в пищу растений, в которых проходит экспрессия туберкулезных антигенов, является перспективным подходом в борьбе с туберкулезом. В этой работе мы сообщаем о создании трансгенных растений салата (Lactuca sativa), содержащих ген сшитого белка антигенов Mycobacterium tuberculosis ESAT6:Ag85B. Трансгенные растения были получены методом трансформации с помощью Agrobacterium tumefaciens. В работе были использованы векторы, содержащие ген esxA, сшитый с геном fbpB. Также векторы содержали селективные гены: ген неомицинфосфотрансферазы (nptII) или фосфинотрицин ацетилтрансферазы (bar). На селективной среде были отобраны трансгенные растения салата. Наличие селективного и целевого генов в геноме этих растений было подтверждено с помощью ПЦР. Трансгенные растения салата были высажены в грунт в условиях теплицы для проведения последующих исследований