НАГРУЖЕНИЕ ГРУНТА ТРАКАМИ ГУСЕНИЧНЫХ МАШИН: ОБЗОР РАСЧЕТНЫХ СХЕМ

The results of investigations in the field of existing soil loading schemes by tracks of tracked vehicles and their effect on the traction force realized by a caterpillar propulsion device are presented. The review shows that most researchers emphasize the important role of lugs in the creation of tractive effort. However, most of the existing methods of calculating the traction force on the clutch are based on one or another specific design scheme that does not depend on the loads acting on the tracks, on the combination of the parameters of the grousers and on the physical and mechanical properties of the soil. The use of these methods does not allow us to consider the sequence and alternative variants of soil disruption, and also to establish a relationship between the magnitude of the tangential force acting on the tract with a wide range of combinations of geometric parameters of the grousers, and to link it to the physical processes taking place in the soil. Consequently, these methods do not fully describe the interaction of the crawler tracks with the ground, which makes it difficult to use them to optimize the geometric parameters of the lugs. The authors proposed an analytical method for analyzing the interaction of soil with a track of a caterpillar engine based on the regularities of the theory of the limiting state of ground masses and the main provisions used in the theory of cutting soil, taking into account the revealed features of this interaction, which makes it possible to investigate the interaction of tracks of a caterpillar propulsion with soil, taking into account the multiphase and alternative options for the destruction of soil between the grousers. This method allows you to choose the parameters of the lugs, providing an improvement in traction and coupling properties of crawler tractors. Приведены результаты исследований в области существующих схем нагружения грунта траками гусеничных машин и их влияния на реализуемую гусеничным движителем силу тяги по сцеплению. Проведенный обзор показывает, что большинство исследователей подчеркивают немаловажную роль грунтозацепов в создании тягового усилия. Однако большая часть существующих методов расчета силы тяги по сцеплению базируется на определенной расчетной схеме, не зависящей от нагрузок, действующих на траки, от сочетания параметров грунтозацепов и от физико-механических свойств грунта. Использование этих методов не позволяет рассмотреть последовательность и альтернативные варианты разрушения грунта, а также установить взаимосвязь величины касательной силы, действующей на трак, с широким спектром сочетаний геометрических параметров грунтозацепов и связать ее с физическими процессами, протекающими в грунте. Следовательно, эти методы не в полной мере описывают взаи- модействие грунтозацепов гусеничного движителя с грунтом, что затрудняет их использование для оптимизации геометрических параметров грунтозацепов. Авторами предложен аналитический метод анализа взаимодействия грунта с траком гусеничного движителя, основанный на закономерностях теории предельного состояния грунтовых масс и основных положений, используемых в теории резания грунта, учитывающий выявленные особенности этого взаимодействия. Данный метод позволяет проводить исследование взаимодействия траков гусеничного движителя с грунтом с учетом многофазности и альтернативных вариантов разрушения грунта, находящегося между грунтозацепами, а также выбирать параметры грунтозацепов, которые обеспечивают улучшение тягово-сцепных качеств гусеничных тягачей

Infiornativity lacrimal fluid interleukins in diagnostics and development of angle-closure glaucoma in elderly subjects

An increased percentage of the elderly subjects in pattern of contemporary society, along with other causes and risk factors, is accompanied by rise in the incidence of glaucoma. By 2020, according to international studies it is expected that prevalence of glaucoma patients in the world would increase up to 80 million subjects. Among the elderly, glaucoma is a common pathology, which development is associated with local disturbances in interleukin profile. However, the features of the latter in patients with primary closed-angle glaucoma in the elderly were poorly examined. Studies of local interleukin status were conducted mainly in patients with suspected or initial manifestations of primary open-angle glaucoma. The features of lacrimal fluid interleukin shift in a target group of elderly patients suffering from stage II primary closed-angle glaucoma virtually gained no attention. In addition, a limited range of local interleukins in patients with such pathology in previous studies was examined. In addition, informativity of lacrimal fluid interleukins in elderly glaucoma patients was not assessed too based on objective methods. The aim of the current study was to outline features and informativity of local interleukin profile indicators in 58 elderly patients with primary closed-angle glaucoma stage II, aged 60—74 years (main group) and 27 age-matched elderly subjects lacking such pathology. The level of interleukins in the lacrimal fluid was determined with the enzyme immunoassay “Multiscan” analyzer (Finland) by using sandwich ELISA (R&D Diagnostic Inc., USA). Informativity of measuring various interleukins was calculated according to the generally accepted formula. It was found that local interleukin profile in elderly patients with primary closed-angle glaucoma was mainly featured with increased amount of IL-2, IL-17, IL-8, but decreased IL-10. Hence, such local interleukins displayed peak informativity. The data obtained should be used in the diagnostics and treatment of such pathology, as well as of applied importance to unveil novel mechanisms behind development, diagnostics and corroboration for selective immuno-tropic therapy of primary closed-angle glaucoma

Синтез управления в продольном канале маловысотного контура беспилотного вертолета

This paper describes the design of the collective pitch control law of an unmanned helicopter in low-level altitude mode. The novelty is using an adaptive inner-loop control with an identifier and a reference model, which automatically provides disturbance compensation in the altitude channel during roll and yaw arbitrary maneuvering. The outer-loop control provides radio altitude hold with desired gain-frequency characteristic of stabilization error.Рассматривается синтез закона управления общим шагом несущего винта беспилотного вертолета в режиме маловысотного полета. Новизной работы является использование в нижнем контуре системы управления адаптивного закона с идентификатором и эталонной моделью, который обеспечивает автоматическую компенсацию возмущений в канале управления высотой при произвольном маневрировании по крену и рысканию. Верхний уровень обеспечивает стабилизацию заданной высоты по сигналам радиовысотомера с желаемой амплитудно-частотной характеристикой для ошибки стабилизации

Функциональная активность нейтрофилов при ожоговом сепсисе

A complex effect of thermal trauma on the immune system triggers the tendency to develop and generalize infection in patients with severe thermal trauma. The phagocytic system, which is represented, first of all, by neutrophilic granulocytes, is significantly altered. Objective: to determine the dynamics of changes in the functional activity of neutrophils in patients with thermal trauma, as well as its prognostic significance in the development of purulent-septic complications of a burn disease. Materials and methods. The functional activity of neutrophils was assessed by spontaneous and induced chemiluminescence responses of whole blood sequentially stimulated with phorbol-12-myristate"13-acetate(PMA) and N-formyl-methionyl-leucyl-phenylalanine (fMLP). 34 patients with a burn disease of different severity were dynamically examined during observation. Results. The newly developed technique was applied to study the responses of whole blood of patients with burn disease to stimuli; data on the functional activity of neutrophils depending on various severities of the disease and response dynamics were obtained. Analysis of chemiluminescent curves of the development of respiratory explosion of neutrophils helped to reveal parameters of the immune system state, namely: a one— or two-phase response to a stimulus, a «rapid phase» neutrophil specific activity, and a «slow phase» neutrophil specific activity. Conclusion. The results revealed trends in alterations of functional activity of neutrophils in burn disease. Diagnostic and prognostic indices of the functional activity of neutrophils for assessing the severity of the disease and the prognosis of the septic process were suggested.Тенденция к развитию и генерализации инфекции у пациентов с тяжелой термической травмой реализуется за счет комплексного влияния термической травмы на иммунную систему. Особенно страдает фагоцитарная система, представленная, в первую очередь, нейтрофильными гранулоцитами. Цель исследования: определение динамики изменения функциональной активности нейтрофилов у пациентов с термической травмой, а также ее прогностической значимости при развитии гнойно-септических осложнений ожоговой болезни. Материалы и методы. Функциональную активность нейтрофилов оценивали на основе спонтанного и индуцированного хемилюминесцентного ответа цельной крови при последовательной стимуляции форбол-12-миристат-13-ацетатом (ФМА) и N-формил-метионил-лейцил-фенилаланином (фМЛФ). Было обследовано 34 пациента с ожоговой болезнью при разной тяжести течения ожоговой болезни и в динамике наблюдения. Результаты. Разработанная новая методика была использована для исследования цельной крови пациентов с ожоговой болезнью, получены данные о функциональной активности нейтрофилов при разной тяжести течения болезни и в динамике. В результате анализа хемилюминесцентных кривых развития респираторного взрыва нейтрофилов выявлены показатели, характеризующие состояние иммунной системы, а именно: одно— или двухфазный ответ на стимул, удельная активность нейтрофила «быстрой фазы», удельная активность нейтрофила «медленной фазы». Заключение. Результаты позволили выделить тенденции изменения функциональной активности нейтрофилов при ожоговой болезни. Предложены диагностические и прогностические показатели функциональной активности нейтрофилов для оценки тяжести болезни и прогноза септического процесса

Hyperbaric Oxygen Therapy in Patients with COVID-19

The aim of the study is to evaluate the efficacy of hyperbaric oxygen therapy and its effect on oxidative stress and apoptosis in patients with new coronavirus infection COVID-19.Materials and methods. 90 patients diagnosed with new coronavirus infection caused by SARS-CoV-2 virus were examined. Hyperbaric oxygen therapy sessions were conducted in 57 patients (38 in severe condition (CT 3-4), 19 in moderate condition (CT 1-2)). The procedures were performed in 1.4-1.6 ATA mode for 40 minutes, 247 sessions in total were performed. The effect of hyperbaric oxygenation was assessed by measuring the level of oxygen saturation, the severity of oxidative stress and apoptosis of blood lymphocytes.Results. In all examined patients with new coronavirus infection caused by SARS-CoV-2, positive changes such as dyspnea reduction and improvement of general well-being were registered after hyperbaric oxygen therapy sessions. The level of oxygen saturation after the end of the hyperbaric oxygen therapy course was 95.0±1.6% (before the course — 91.3±5.9%), which allowed to return almost all patients to spontaneous respiration without the need for further oxygenation therapy. Hyperbaric oxygen therapy did not reduce the total antioxidant activity, however, it was associated with a decrease in the blood malone dialdehyde from 4.34±0.52 pmol/l to 3.98±0.48 pmol/l and a decrease in open circuit potential of platinum electrode from -22.78±24.58 mV to -37.69±17.4 mV. Besides, the positive effect of hyperbaric oxygen therapy was manifested in normalization of blood cell apoptosis.Conclusion. Hyperbaric oxygen therapy in patients with new coronavirus infection caused by the SARS-CoV-2 virus is an effective treatment method with multiple effects resulting in improvement of subjective indicators of the patients' condition, increase of hemoglobin oxygen saturation, decrease of lipid peroxidation intensity, activation of antioxidant system, restoration of pro- and antioxidant balance and apoptosis normalization

Септический шок у взрослых: клинические рекомендации Общероссийской общественной организации «Федерация анестезиологов и реаниматологов»

В статье представлены основные положения клинических рекомендаций по септическому шоку у взрослых, утвержденных Общероссийской общественной организацией «Федерация анестезиологов и реаниматологов» в 2023 г. Актуальность проблемы связана со значительной распространенностью и высокими показателями летальности при септическом шоке. Рекомендации включают вопросы этиологии, патогенеза, клинической картины, методов лабораторной и инструментальной диагностики септического шока. Представлена стартовая интенсивная терапия септического шока, включая подходы по назначению вазопрессорных и инотропных препаратов, рекомендации по выбору антибактериальных препаратов, особенности инфузионной и адъювантной терапии, в том числе при рефрактерном к терапии септическом шоке. Обсуждены вопросы хирургического лечения очага инфекции. Представлены критерии качества оказания медицинской помощи взрослым пациентам с септическим шоком и алгоритмы действий врача при диагностике и интенсивной терапии пациентов с септическим шоком

Epidemiology of intra-abdominal infection and sepsis in critically ill patients: “AbSeS”, a multinational observational cohort study and ESICM Trials Group Project

Purpose: To describe the epidemiology of intra-abdominal infection in an international cohort of ICU patients according to a new system that classifies cases according to setting of infection acquisition (community-acquired, early onset hospital-acquired, and late-onset hospital-acquired), anatomical disruption (absent or present with localized or diffuse peritonitis), and severity of disease expression (infection, sepsis, and septic shock). Methods: We performed a multicenter (n = 309), observational, epidemiological study including adult ICU patients diagnosed with intra-abdominal infection. Risk factors for mortality were assessed by logistic regression analysis. Results: The cohort included 2621 patients. Setting of infection acquisition was community-acquired in 31.6%, early onset hospital-acquired in 25%, and late-onset hospital-acquired in 43.4% of patients. Overall prevalence of antimicrobial resistance was 26.3% and difficult-to-treat resistant Gram-negative bacteria 4.3%, with great variation according to geographic region. No difference in prevalence of antimicrobial resistance was observed according to setting of infection acquisition. Overall mortality was 29.1%. Independent risk factors for mortality included late-onset hospital-acquired infection, diffuse peritonitis, sepsis, septic shock, older age, malnutrition, liver failure, congestive heart failure, antimicrobial resistance (either methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, extended-spectrum beta-lactamase-producing Gram-negative bacteria, or carbapenem-resistant Gram-negative bacteria) and source control failure evidenced by either the need for surgical revision or persistent inflammation. Conclusion: This multinational, heterogeneous cohort of ICU patients with intra-abdominal infection revealed that setting of infection acquisition, anatomical disruption, and severity of disease expression are disease-specific phenotypic characteristics associated with outcome, irrespective of the type of infection. Antimicrobial resistance is equally common in community-acquired as in hospital-acquired infection

The clinical relevance of oliguria in the critically ill patient : Analysis of a large observational database

Funding Information: Marc Leone reports receiving consulting fees from Amomed and Aguettant; lecture fees from MSD, Pfizer, Octapharma, 3 M, Aspen, Orion; travel support from LFB; and grant support from PHRC IR and his institution. JLV is the Editor-in-Chief of Critical Care. The other authors declare that they have no relevant financial interests. Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Urine output is widely used as one of the criteria for the diagnosis and staging of acute renal failure, but few studies have specifically assessed the role of oliguria as a marker of acute renal failure or outcomes in general intensive care unit (ICU) patients. Using a large multinational database, we therefore evaluated the occurrence of oliguria (defined as a urine output 16 years) patients in the ICON audit who had a urine output measurement on the day of admission were included. To investigate the association between oliguria and mortality, we used a multilevel analysis. Results: Of the 8292 patients included, 2050 (24.7%) were oliguric during the first 24 h of admission. Patients with oliguria on admission who had at least one additional 24-h urine output recorded during their ICU stay (n = 1349) were divided into three groups: transient - oliguria resolved within 48 h after the admission day (n = 390 [28.9%]), prolonged - oliguria resolved > 48 h after the admission day (n = 141 [10.5%]), and permanent - oliguria persisting for the whole ICU stay or again present at the end of the ICU stay (n = 818 [60.6%]). ICU and hospital mortality rates were higher in patients with oliguria than in those without, except for patients with transient oliguria who had significantly lower mortality rates than non-oliguric patients. In multilevel analysis, the need for RRT was associated with a significantly higher risk of death (OR = 1.51 [95% CI 1.19-1.91], p = 0.001), but the presence of oliguria on admission was not (OR = 1.14 [95% CI 0.97-1.34], p = 0.103). Conclusions: Oliguria is common in ICU patients and may have a relatively benign nature if only transient. The duration of oliguria and need for RRT are associated with worse outcome.publishersversionPeer reviewe