59 research outputs found

    Queueing system GI/GI/∞ with n types of customers

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    The total capacity of customers in the MMPP/GI/∞ queueing system

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    In the paper, the infinite-server queueing system with a random capacity of customers is considered. In this system, the total capacity of customers is analysed by means of the asymptotic analysis method with high-rate Markov Modulated Poisson Process arrivals. It is obtained that the stationary probability distribution of the total customer capacity can be approximated by the Gaussian distribution. Parameters of the approximation is also derived in the pape

    Resource retrial queue with two orbits and negative customers

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    In this paper, a multi-server retrial queue with two orbits is considered. There are two arrival processes of positive customers (with two types of customers) and one process of negative customers. Every positive customer requires some amount of resource whose total capacity is limited in the system. The service time does not depend on the customer’s resource requirement and is exponentially distributed with parameters depending on the customer’s type. If there is not enough amount of resource for the arriving customer, the customer goes to one of the two orbits, according to his type. The duration of the customer delay in the orbit is exponentially distributed. A negative customer removes all the customers that are served during his arrival and leaves the system. The objects of the study are the number of customers in each orbit and the number of customers of each type being served in the stationary regime. The method of asymptotic analysis under the long delay of the customers in the orbits is applied for the study. Numerical analysis of the obtained results is performed to show the influence of the system parameters on its performance measure

    Communication of COVID-19 consequences in the Baltic States inforsphere

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    This article seeks to describe the dynamics of COVID-19 in the Baltic States and to analyse the ways of communicating the threat and its consequences. Particular attention is paid to the media strategies pursued in the study area. The research is based on Russian and English texts from the Baltic media, WHO official documents and datasets, as well as initiatives of the Baltic Sea region organisations (2020) counteracting COVID-19. A combination of these sources builds up an objective view of the situation and demonstrates how the pandemic and its consequences are represented in public consciousness given a certain pragmatic goal. The pandemic is a new type of threat; its consequences demonstrate a tendency towards negative synergy and a category shift from soft threats to hard ones. The research shows that several key strategies - counter-active, projective, conservative, mobilising, resilient, and reflective - are used to communicate the threat and its consequences in the media

    Multi-service resource queue with the multy-component Poisson arrivals

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    In many papers devoted to telecommunication systems, multiservice queueing models with heterogeneous customer arrivals are given. As a rule, there is streaming traffic, corresponding to the audio and video conference, and elastic traffic, corresponding to the data and file transmission. Different types of traffic require different quality of service, therefore the multi-service systems are also differentiated service systems. Such papers are aimed at developing a framework for estimating the quality of service indicators in new generation multi-service networks. This paper considers a multiservice resource queueing system with three Poisson arrivals, one of which is splitting. The equation for the probabilities distribution of the total resource amounts on the system blocks is compiling by the dynamic screening method, and using the characteristic function of the stationary distribution, the solution is obtaining. The numerical characteristics of the system performance are obtained by the method of moments using characteristic function. A numerical example shows that arrivals intensity growing increases optimal total resource amounts on system blocks in the system with limited resources, and the splitting arrivals affect the correlation between total resource amounts

    THE EFFECT OF TOPICAL DRUGS ON THE LOCAL CONCENTRATIONS OF IL-5 AND MOMETASONE FUROATE IN CHRONIC POLYPOUS RHINOSINUSITIS

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    Long-term persistent inflammation is the main factor of pathogenesis in chronic polypous rhinosinusitis (CRSwNP).  Perspective subject of current clinical otorhinolaryngology is the modification of drugs containing topical glucocorticosteroids to increase local bioavailability, reduce the concentration of glucocorticosteroids, and reduce the local inflammatory response. The aim of the work was to evaluate the effect of urea, magnesium sulfate, mannitol on the concentrations of mometasone furoate and IL-5 in the polypous tissue of patients with CRSwNP. The study included 146patients with CRSwNP aged 18 to 62 years.  Biopsies of polypous tissue were taken during polypotomy. In liquids obtained by microdialysis of polypous tissues, mometasone concentrations were determined by high-performance liquid chromatography. Concentrations of cytokines IL-3, IL-4, IL-5 and IL-10 in blood serum and IL-5 in microdialysates of polypous tissue were measured by ELISA.  The average age of patients with CRSwNP was 42.9 ±7.2 years, among them men – 93 (63,69%), women – 53 (36,30%).). Clinical parameters the severity of the disease on the SNOT-22 scale in patients with CRSwNP significantly exceeded those in the control group (p≤ 0.05). The results of the biochemical analysis of microdialyzates of polypous tissue showed an increase in the content of Na+ ions in the resistant form of CRSwNP compared with the sensitive and dependent forms (p <0.05). Curves with the level of mometasone furoate were obtained in all the studied samples. It was found that the addition of magnesium sulfate solution to mometasone increases the Cmax of mometasone to 154ng/ml in biological fluids after microdialysis. When urea solution is added to mometasone, Cmax increases to 198ng/ml. In the native nasal polypous tissue dialysate, IL-5 levels were 89±2.01 pg/ml. 2 hours after the addition of mometasone furoate, IL-5 concentrations decreased to 61± 3.5 pg / ml, after the addition of urea - to 69± 2.98 pg / ml (p ≤ 0.01, compared with the control without the addition of drugs). Analysis of serum cytokine levels showed that IL-5 concentrations in patients with CRSwNP significantly exceeded (on average more than three times) those in the control group (p≤0.05). There was a tendency to increase IL-3 and IL-4 (in 2 times) and to decrease IL-10 levels of in blood sera (by more than 1.5 times) in patients with CRSwNP compared with the control group. The results obtained help to develop new clinical approaches to increase the bioavailability of topical glucocorticosteroids, which allow to increase the effectiveness of basic therapy of CRSwNP and develop a treatment for the prevention of resistant forms of polyposis

    ПОВЫШЕНИЕ УРОВНЯ ПРОВОСПАЛИТЕЛЬНЫХ ЦИТОКИНОВ В ПЛАЗМЕ КРОВИ У ПАЦИЕНТОВ С ХРОНИЧЕСКОЙ ТРОМБОЭМБОЛИЧЕСКОЙ ЛЕГОЧНОЙ ГИПЕРТЕНЗИЕЙ

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    HighlightsIL-8 and MCP-1 have a significant role in the CTEPH pathogenesis, which indicates the importance of nonspecific immunity in the formation and progression of CTEPH. The coupling between cytokines and hemodynamic parameters, cardiac structural changes and plasma biochemical parameters were determined. AbstractBackground. Chronic thromboembolic pulmonary hypertension (CTEPH) pathogenesis is complex and not fully understood. Particular attention to the microvascular damage genesis in CTEPH is given to aseptic inflammation, which in turn could be mediated through various molecular mechanisms. According to the conflicting and incomplete data on changes in the profile of factors controlling inflammation in CTEPH, research in this field would identify new therapeutic targets for the prevention and treatment of CTEPH.Aim. To study the profile of plasma proinflammatory cytokines in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and evaluate the coupling of these cytokines with the main morphofunctional and laboratory values of the disease severity.Methods. 34 patients with CTEPH were included in this study. To characterize the group, the following methods were used: echocardiographic examination, catheterization of the right cardiac chambers. Biomarkers of heart failure, systemic inflammation, as well as erythropoiesis and iron metabolism were assessed in all patients. The control group included 10 donors. To study the proinflammatory cytokine profile in plasma, interleukins (IL) 6, 8, 18, monocyte chemoattractant protein-1 (MCP-1) and matrix metalloproteinase 9 were determined using standard enzyme-linked immunosorbent assay (ELISA) kits.Results. Hemodynamic and morphofunctional changes in the pulmonary circulation specific to pulmonary hypertension were determined with catheterization of the right cardiac chambers and echocardiography. During plasma proinflammatory cytokines analysis, a significant increase in the level of IL-8 (p = 0.030) and MCP-1 (p = 0.031) in CTEPH group compared to the control group was observed. No significant differences for other analyzed markers were found. In the elaboration of the correlation analysis, moderate inverse coupling between proinflammatory markers and hemodynamic parameters characterizing the CTEPH severity were revealed, as well as positive correlations with parameters of remodeling of the right cardiac chambers and iron metabolism.Conclusion. The increased levels of IL-8 and MCP-1 in patients with CTEPH identified in the present study indicate a significant role of nonspecific immunity in the formation and progression of CTEPH. The coupling between cytokines and hemodynamic parameters, structural cardiac changes and plasma biochemical parameters were determined. Based on the obtained data, it is possible to develop new medicinal substances, targeting towards proinflammatory cytokines, their receptors and signaling pathways.Основные положенияИЛ-8 и MCP-1 играют существенную роль в патогенезе хронической тромбоэмболической легочной гипертензии, что указывает на важное значение неспецифического иммунитета в формировании и прогрессировании данного заболевания. Определена связь цитокинов с показателями гемодинамики, структурными изменениями сердца и биохимическими показателями плазмы крови. РезюмеАктуальность. Патогенез хронической тромбоэмболической легочной гипертензии (ХТЭЛГ) сложен и до конца не изучен. Особое внимание в генезе микрососудистого поражения при ХТЭЛГ уделяют асептическому воспалению, которое в свою очередь может быть опосредовано различными молекулярными механизмами. Учитывая противоречивые и неполные данные об изменении профиля факторов, контролирующих воспаление при ХТЭЛГ, исследования в этой области позволят определить новые терапевтические мишени для профилактики и лечения ХТЭЛГ.Цель. Изучить профиль провоспалительных цитокинов в плазме крови у пациентов с ХТЭЛГ и оценить связь этих цитокинов с основными морфофункциональными и лабораторными показателями тяжести течения заболевания.Материалы и методы. В исследование включены 34 пациента с верифицированным диагнозом ХТЭЛГ. Для характеризации группы использованы эхокардиографическое исследование и катетеризация правых камер сердца. У всех больных оценены биомаркеры сердечной недостаточности, системного воспаления, а также эритропоэза и обмена железа. В группу контроля вошли 10 человек-доноров. Для изучения профиля провоспалительных цитокинов в плазме крови определены интерлейкины (ИЛ) 6, 8, 18, моноцитарный хемоаттрактантный белкок 1 (MCP-1) и матриксная металлопротеиназа 9 с помощью стандартных наборов для иммуноферментного анализа.Результаты. По данным катетеризации правых камер сердца и эхокардиографии определены гемодинамические и морфофункциональные изменения малого круга кровообращения, характерные для легочной гипертензии. При анализе уровня провоспалительных цитокинов в плазме крови в группе ХТЭЛГ по сравнению с группой контроля отмечено значимое повышение ИЛ-8 (p = 0,030) и MCP-1 (p = 0,031). По другим проанализированным маркерам значимых различий не получено. В результате корреляционного анализа выявлены умеренные обратные взаимосвязи провоспалительных маркеров с гемодинамическими параметрами, характеризующими тяжесть ХТЭЛГ, а также положительные корреляционные связи с показателями ремоделирования правых камер сердца и обмена железа.Заключение. Установленное в настоящем исследовании повышение уровней ИЛ-8 и MCP-1 у пациентов с ХТЭЛГ указывает на значительную роль неспецифического иммунитета в формировании и прогрессировании ХТЭЛГ. Определены взаимосвязи цитокинов с показателями гемодинамики, структурными изменениями сердца и биохимическими показателями плазмы крови. На основе полученных данных возможна разработка новых лекарственных субстанций, мишенями для которых будут провоспалительные цитокины, их рецепторы и сигнальные пути
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