Проектирование и разработка имитационной модели мультиклиентского кластера баз данных

One of the main trends of recent years in software design is a shift to a Software as a Service (SaaS) paradigm which brings a number of advantages for both software developers and end users. However, along with these benefits this transition brings new architectural challenges. One of such challenges is the implementation of a data storage that would meet the needs of a service-provider, at the same time providing a fairly simple application programming interface for software developers. In order to develop effective solutions in this area, the architectural features of cloud-based applications should be taken into account. Among others, such key features are the need for scalability and quick adaptation to changing conditions. This paper provides a brief analysis of the problems in the field of cloud data storage systems based on the relational model and it proposes the concept of database cluster designed for applications with a multi-tenant architecture. Besides, the article describes a simulation model of such a cluster, as well as the main stages of its development and the main principles forming its foundation.Одной из главных тенденций последних лет в проектировании программного обеспечения стал переход к парадигме Software as a Service (SaaS), которая несет ряд неоспоримых преимуществ как для компаний-разработчиков ПО, так и для конечных пользователей. Однако вместе с этими преимуществами данный переход несет и новые архитектурные вызовы, одним из которых является организация хранилища данных, которое могло бы удовлетворить нужды компании-провайдера услуг, обеспечив достаточно простой прикладной интерфейс для разработчиков. Для разработки эффективного решения в данной области следует принимать во внимание особенности архитектуры облачных приложений, ключевыми из которых являются потребность в простом масштабировании и быстрой адаптации к меняющимся условиям. В данной работе проводится краткий анализ существующих проблем в области организации облачных систем хранения данных, основанных на реляционной модели, а также предлагается концепция кластера РСУБД, предназначенного для обслуживания приложений с мультиклиентской архитектурой. Кроме того, в статье дается описание имитационной модели подобного кластера, а также основных этапов ее разработки и принципов, заложенных в ее основу

Применение стохастических метаэвристик в задаче управления данными в мультиклиентском кластере баз данных

A multi-tenant database cluster is a concept of a data-storage subsystem for cloud applications with the multi-tenant architecture. The cluster is a set of relational database servers with the single entry point, combined into one unit with a cluster controller. This system is aimed to be used by applications developed according to Software as a Service (SaaS) paradigm and allows to place tenants at database servers so that providing their isolation, data backup and the most effective usage of available computational power. One of the most important problems about such a system is an effective distribution of data into servers, which affects the degree of individual cluster nodes load and faulttolerance. This paper considers the data-management approach, based on the usage of a load-balancing quality measure function. This function is used during initial placement of new tenants and also during placement optimization steps. Standard schemes of metaheuristic optimization such as simulated annealing and tabu search are used to find a better tenant placement.Мультиклиентский кластер баз данных – это концепция хранилища данных для облачных приложений с мультиклиентской архитектурой. Кластер представляет собой набор серверов реляционных баз данных с единой точкой входа, объединенных в одно целое и работающих под управлением контроллера кластера. Данная система нацелена на использование приложениями, разрабатываемыми в соответствии с парадигмой Software as a Service (SaaS), и позволяет разместить на предоставленных серверах данные большого количества клиентов таким образом, чтобы обеспечить их изоляцию, резервирование и наиболее эффективное использование предоставленных вычислительных мощностей. Одной из наиболее важных задач при разработке системы подобного рода является эффективное распределение данных по серверам, которое определяет степень загруженности отдельных узлов, а также устойчивость системы к сбоям. В работе рассматривается подход к управлению данными, основанный на применении функции оценки эффективности балансировки нагрузки. Данная функция применяется как при первичном размещении клиентов, так и для оптимизации уже имеющегося распределения клиентов. Оптимизация размещения ведется по стандартным схемам стохастических метаэвристик: имитации отжига (simulated annealing) и поиска с запретами (tabu search)

Impact of the COVID-19 Pandemic on Myocardial Revascularization in Patients with Acute Coronary Syndrome in the Russian Federation

Aim. To compare and analyze the results of myocardial revascularization in the Russian Federation (RF) with acute coronary syndrome (ACS) before the onset (2018-2019) and during the novel coronavirus infection (COVID-19) pandemic (2020-2021).Material and methods. The analysis included the number of cases of ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation acute coronary syndrome (NSTE-ACS), the number of cases of myocardial revascularization in the above forms of ACS, the number of deaths depending on the form of ACS and the method performed revascularization. The period of time before the start of the coronavirus pandemic corresponded to the annual data received in the Russian Federation for 2018-2019. The period of the coronavirus disease pandemic corresponded to the annual data received in the country for 2020-2021. Absolute, relative, estimated values of patient hospitalization, myocardial revascularization procedures, and mortality in ACS were compared between time periods before and during the COVID-19 pandemic. The data for analysis were obtained from the monitoring of the Ministry of Health of Russia.Results. In 2018 and 2019 in the RF, 531,019 and 501,238 patients were hospitalized with a diagnosis of ACS, and during the pandemic (2020-2021) - 403,931 and 397,930 patients, respectively. Reduction in the number of patients diagnosed with ACS admitted to hospitals in Russia by 22.32% in 2020-2021 years was mainly due to a significant decrease in hospitalizations of patients with a diagnosis of NSTE-ACS (by 29.03%). At the same time, admission to clinics of patients with STEMI decreased only by 6.02%. During the COVID-19 pandemic, mortality increased significantly in PPCI (by 9.6%) and in the general STEMI group (by 12.3%); significantly increased mortality both in the general group (by 48%) and during PCI in patients with NSTE-ACS (by 28.6%); there was an increase in the average annual number of PPCI (by 12.6%), which was accompanied by an increased average annual number of PPCI per 1 million of population (up to 451 per 1 million of population); a slight increase in the average time "symptom-balloon" (by 2 minutes) was recorded; there was an absolute slight decrease and a relative increase in the number of PCIs in NSTE-ACS (by 2.7% and 37.1%, respectively). In 2021, in the Russian Federation, primary PCI was performed in 50.2%, thrombolytic therapy - in 23.1%, and 26.7% of patients remained without reperfusion. Pharmacoinphasive strategy was applied in 60%, and isolated thrombolysis - in 40% of patients.Conclusion. During the COVID-19 pandemic, revascularization in patients with ACS in Russia corresponded to the following trends recorded in the literature: increased hospital mortality in PPCI and in the general STEMI group; hospital mortality both in the general group and during PCI in patients with NSTE-ACS. The indicators of myocardial revascularization in ACS in the RF during the pandemic were fundamentally different from the data of Western countries: there was an increase in the average annual number of PPCI and the average annual number of PPCI per 1 million population; a slight increase in the average symptom-balloon time was recorded; revealed an absolute slight decrease and a relative increase in the number of PCIs in NSTE-ACS

Russian guidelines for sudden cardiac death risk assessment and prevention (second edition) – 2018. Pocket version

cardiovascular diseases, sudden cardiac death, risk, treatment, preventionCardiovascular mortality in Russia is one of the highest in the world reaching 614 deaths per 100,000 annually. The main causes of death from cardiovascular diseases are the progression of congestive heart failure (about half of all cases) and sudden cardiac death (the other half). Thus, we can assume that the incidence of sudden cardiac death in 2016 was no less than 300,000. In the abbreviated version of the National Recommendations in English, the principles of decision-making algorithms in various clinical situations are used

Improvement of cardiovascular risk assessment using machine learning methods

The increase in the prevalence of cardiovascular diseases (CVDs) specifies the importance of their prediction, the need for accurate risk stratification, preventive and treatment interventions. Large medical databases and technologies for their processing in the form of machine learning algorithms that have appeared in recent years have the potential to improve predictive accuracy and personalize treatment approaches to CVDs. The review examines the application of machine learning in predicting and identifying cardiovascular events. The role of this technology both in the calculation of total cardiovascular risk and in the prediction of individual diseases and events is discussed. We compared the predictive accuracy of current risk scores and various machine learning algorithms. The conditions for using machine learning and developing personalized tactics for managing patients with CVDs are analyzed

BMI1 regulates PRC1 architecture and activity through homo- and hetero-oligomerization.

BMI1 is a core component of the polycomb repressive complex 1 (PRC1) and emerging data support a role of BMI1 in cancer. The central domain of BMI1 is involved in protein-protein interactions and is essential for its oncogenic activity. Here, we present the structure of BMI1 bound to the polyhomeotic protein PHC2 illustrating that the central domain of BMI1 adopts an ubiquitin-like (UBL) fold and binds PHC2 in a beta-hairpin conformation. Unexpectedly, we find that the UBL domain is involved in homo-oligomerization of BMI1. We demonstrate that both the interaction of BMI1 with polyhomeotic proteins and homo-oligomerization via UBL domain are necessary for H2A ubiquitination activity of PRC1 and for clonogenic potential of U2OS cells. Here, we also emphasize need for joint application of NMR spectroscopy and X-ray crystallography to determine the overall structure of the BMI1-PHC2 complex

Non-ST-segment elevation acute coronary syndrome in elderly patients and long-livers. Features of treatment. Literature review and case report

Despite the growing population of elderly people and long-livers every year, the treatment of acute coronary syndrome in these groups is not fully developed and is not regulated in clinical guidelines due to the lack of large randomized clinical trials. The article presents a literature review covering the following issues arising during clinical decision-making in the treatment of non-ST-segment elevation acute coronary syndrome in this group of patients: selection of invasive treatment strategy, scope of myocardial revascularization, appointment of dual antiplatelet therapy taking into account the bleeding risk, decreased renal function and senile asthenia. In addition, a case report of successful treatment of a 101-year-old female patient with non-ST-segment elevation myocardial infarction, who underwent percutaneous coronary intervention with stenting of infarct-related artery, was presented

Unsolved Issues of Atherosclerosis Prevention and of Adequate Lipid-lowering Therapy in Patients with Acute Ischemic Cerebrovascular Accident

The existing system of medical care for patients with acute cerebrovascular accident of atherothrombotic genesis, namely lipid metabolism disorders, the modern evidence base for lipid-lowering therapy in this category of patients and the feasibility of interdisciplinary interaction of cardiologists and neurologists were discussed at a meeting of the expert council of cardiologists and neurologists in Moscow on 2021 July 7

Transcatheter mitral valve edge-to-edge repair in patients with severe mitral regurgitation: data from the MitraClip Russia Trial

Aim. To study the immediate and short-term outcomes of transcatheter mitral valve edge-to-edge repair with the MitraClip NT in patients with severe mitral regurgitation as part of the MitraClip Russia prospective single-center study.Material and methods. The study included 16 patients (men, 10; women, 6) with mean age of 70,1±2,1 years (mean Euroscore II, 6,90±5,56%; STS, 6,33±3,94%). Immediate technical success was defined as successful access, delivery, and removal of the device, and adequate placing the clip(s) to reduce the mitral regurgitation to grade 2 or below without the need for device- or procedure-related reintervention.Results. Immediate technical success was achieved in all patients. The average number of implanted clips per 1 patient was 1,7. In 1 patient (6,3%), a clip was attached to one mitral leaflet, which required an non-scheduled implantation of a second clip. In hospital mortality was 6,3%: a 92-year-old patient on the 3rd day after the operation had a sudden cardiac arrest followed by coma, hemispheric ischemic stroke and death on the 6th day. An autopsy revealed an iatrogenic atrial septal defect. Echocardiography performed on the 10th and 30th day after surgery showed a decrease in mitral regurgitation grade in 15 patients, while grade 3 residual mitral regurgitation did not reveal in any patient.Conclusion. Transcatheter mitral valve edge-to-edge repair with the MitraClip is a minimally invasive method for treating severe symptomatic mitral regurgitation (degenerative and functional). The results demonstrate high immediate efficacy and an acceptable safety profile in high surgical risk patients. Based on the analysis of death causes, the authors conclude that it is necessary to include initial pulmonary hypertension above 75 mm Hg as a relative contraindication to this procedure. The study limitations are the small sample size and short follow-up period