134 research outputs found

    Discontinuous Bifurcations under 2-DOF Vibroimpact System Moving

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    Dynamic behaviour of strongly nonlinear non-smooth discontinuous vibroimpact system isstudied. Under variation of system parameters we find the disconti nuousbi furcati onsthat are the dangerousones. It is phenomenon unique to non-smooth systems with discontinuous right-hand side. We investigate the 2-DOF vibroimpact system by numerical parameter continuation method in conjunction with shooting and Newton-Raphson methods, Wife simulate the impact by nonlinear contact interactive force according to Hertz's contact law. We find the discontinuous bifurcations by Floquet multipliers values. At such points set-valued Floquet multipliers cross the unit circle by jump that istheir moduli becoming more than unit by jump. Wealso learn the bifurcation picture change when the impact between system bodi es became the soft one due the change of system parameters, This paper is the continuation of the previous works

    Approach of the NGC 1977 star cluster to the TOI-2796 host star

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    We study of possible encounters in past epochs of the open star cluster NGC 1977 with host stars. For this purpose, the age of the cluster was determined based on our catalog data. Stars with planetary systems were selected from the NASA Archive. The age of the cluster was determined using the color - absolute magnitude diagram and the isochron system. By extending the track of the movement of the cluster and stars in past epochs, 10 Myr. The time of the maximum approach 32 pc of the host star with planetary system TOI-2796 with the NGC 1977 are found. The place of approach in the sky is shown, this point can be considered as the place of appearance of interstellar comets. Thus, the result of our work is that the we found approach of the host star to the cluster entailed effects associated with the gravitational influence of the cluster on the nuclei of comets located in the outer parts of the Oort cloud of the planetary system. The effect of approach on comets is estimated

    Meteoprotective properties of melaxen in old and middle aged patients with ischemic heart disease in combination with arterial hypertension

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    We studied 102 patients (mean age 60.1±3.3 years) with arterial hypertension (AH) II-III stage, grade 2-3 and ischemic heart disease (exertional angina functional class (FC) I-II, postinfarction cardiosclerosis). The control group of patients received traditional therapy (TT): beta -blockers, calcium channel blockers, ACE inhibitors, antiplatelet agents, diuretics and nitrate

    TAVISCORE: a computer program for risk stratification of complications after aortic valve interventions in patients with reduced ejection fraction

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    Aim. To demonstrate the TAVISCORE program designed to stratify the risk of complications after aortic valve (AV) interventions in patients with reduced ejection fraction.Material and methods. For the period from 2015-2022 at the Almazov Federal North-West Medical Research Center, 128 interventions on AV were performed for aortic stenosis in patients with reduced ejection fraction as follows: 61 — surgical AV replacement (SAVR), 67 — transcatheter aortic valve implantation (TAVI). To create an interactive calculator TAVISCORE (link for free download: https://drive.google.com/file/d/1a3s2MK6Tpk0cIQ_aMB7xe63upEwJsJOh/view?usp=sharing) all patients were combined into one group. For each factor present in the patient, the prognostic coefficient, its contribution to the likelihood of an event in the long-term follow-up period (death, myocardial infarction, stroke), was calculated. The next step, based on the calculations obtained and using the Python 3.10.6 language, was the creation of the TAVISCORE program.Results. The TAVISCORE was created for the personalized choice of tactics for the treatment of patients with aortic stenosis. It contains 54 risk factors and makes it possible to determine probability of cardiac or non-cardiac events in the long-term follow-up period after SAVR and TAVI. Thus, a tactic with lower probability of a complication can be chosen as optimal in this particular case. Retrospective use of the TAVISCORE after surgery can identify patients at high risk of complications, which will allow them to be selected for more thorough management and more frequent screening.Conclusion. The TAVISCORE can be used by a multidisciplinary consensus to select the treatment tactics and stratify the risk of complications after different AV replacement variants in patients with a reduced ejection fraction. Further prospective testing of this program is required

    ВЛИЯНИЕ СТРОЕНИЯ ЭВАПОРИТОВОЙ ФОРМАЦИИ НА ФОРМИРОВАНИЕ СТРУКТУР СОЛЯНОЙ ТЕКТОНИКИ И ЛОВУШЕК УГЛЕВОДОРОДОВ (ПО РЕЗУЛЬТАТАМ ЧИСЛЕННОГО МОДЕЛИРОВАНИЯ ГАЛОКИНЕЗА В ПРИКАСПИИ)

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    Within the Pre-Caspian sedimentary basin, there is certain regularity in the distribution of types of structures of salt tectonics. It is characterized by concentric zoning corresponding to the change in the sedimentation thickness of the evaporite sequence. As it increases from 0 to 6 km towards the center of the basin, stamp (embryonic) salt uplifts are replaced by salt pillows first and then by salt domes and diapirs, finally changing to salt massifs and amoeboid-shaped salt ridges. In addition, diapirs in the sections of the Pre-Caspian basin, drawn from the drilling and seismic data, are shaped like high-amplitude "fingers" with a flat base, which is not a typical picture of the Rayleigh – Taylor instability development. Since halokinesis is the main factor controlling the migration and accumulation of hydrocarbons in the Preaspian region, background and aim of prospecting and exploration require identifying the specifics of the formation of various types of salt structures and the relationship between their location patterns and halokinesis process.Numerical simulation shows that, depending on the instable layer thickness and its relationship with the total thickness of the overlying layers, the instability development occurs at different rates, forming different types of structures. When the thickness of the instable layer is greater than or comparable to the thickness of the denser overburden, there occur the salt masses. A greater thickness of the overlying layer gives rise to the formation of classical mushroom-shaped diapirs. A small-thickness low-density layer first undergoes a full bending as it rises, so that its top and bottom turn out to be morphologically similar to each other, thus giving a misleading impression of ordinary stamp folds. Somewhat greater thickness of the low-density layer leads to the development of "pillows" therein. Detailed modeling made it possible to relate the specific shape of the Pre-Caspian diapirs to the fact that the basal and top horizons of the evaporite formation, being composed mainly of terrigenous, carbonate and sulfate rocks, have a normal, non-inverse density and mask complex diapiric structures of halite-saturated domal cores.В пределах Прикаспийского осадочного бассейна наблюдается определенная закономерность в размещении структур соляной тектоники разного типа. Она характеризуется концентрической зональностью, соответствующей изменению седиментационной мощности эвапоритовой толщи. По мере ее нарастания от периферии к центру бассейна от 0 до 6 км штамповые (эмбриональные) соляные поднятия сменяются соляными подушками, затем – соляными куполами и диапирами и, наконец, соляными массивами и амебообразными соляными хребтами. Кроме того, диапиры на разрезах Прикаспия, построенных по данным бурения и сейсморазведки, имеют довольно специфический облик высокоамплитудных «пальцев» с плоской подошвой, не характерный для типичной картины развития неустойчивости Рэлея – Тейлора. Поскольку галокинез является основным фактором, контролирующим миграцию и накопление углеводородов в Прикаспии, для обоснованного нацеливания поисково-разведочных работ нужно выяснить специфику формирования различных типов соляных структур и связи закономерностей их размещения с ходом процесса галокинеза.Численным моделированием показано, что в зависимости от толщины неустойчивого слоя и ее соотношения с общей толщиной перекрывающих слоев развитие неустойчивости идет с разной скоростью, формируя различные типы структур. Когда мощность неустойчивого слоя больше или сопоставима с мощностью более плотных перекрывающих пород, формируются соляные массивы. При большей мощности перекрывающего слоя формируются классические грибообразные диапиры. При малой толщине низкоплотного слоя он, всплывая, вначале изгибается целиком, так что морфология его кровли и подошвы оказывается подобной и возникает обманчивое впечатление обычных штамповых складок. Там, где толщина низкоплотного слоя несколько больше, развиваются «подушки». Детальное моделирование позволило установить, что специфическая форма диапиров Прикаспия может быть обусловлена тем, что базальные и венчающие горизонты эвапоритовой формации, будучи сложенными преимущественно терригенными, карбонатными и сульфатными породами, имеют нормальную, неинверсионную, плотность и маскируют сложные диапировые структуры насыщенных галитом ядер куполов

    Relationship of the Content of Systemic and Endobronchial Soluble Molecules of CD25, CD38, CD8, and HLA-I-CD8 and Lung Function Parameters in COPD Patients

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    © 2017 Nailya Kubysheva et al. The definition of new markers of local and systemic inflammation of chronic obstructive pulmonary disease (COPD) is one of the priority directions in the study of pathogenesis and diagnostic methods improvement for this disease. We investigated 91 patients with COPD and 21 healthy nonsmokers. The levels of soluble CD25, CD38, CD8, and HLA-I-CD8 molecules in the blood serum and exhaled breath condensate (EBC) in moderate-to-severe COPD patients during exacerbation and stable phase were studied. An unidirectional change in the content of sCD25, sCD38, and sCD8 molecules with increasing severity of COPD was detected. The correlations between the parameters of lung function and sCD8, sCD25, and sHLA-I-CD8 levels in the blood serum and EBC were discovered in patients with severe COPD. The findings suggest a pathogenetic role of the investigated soluble molecules of the COPD development and allow considering the content of sCD8, sCD25, and sHLA-I-CD8 molecules as additional novel systemic and endobronchial markers of the progression of chronic inflammation of this disease

    Неблагоприятные события, произошедшие у больных ревматоидным артритом при длительном наблюдении

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       Comorbid diseases and adverse events that occur in patients with rheumatoid arthritis (RA) negatively affect the outcomes of RA (radiological progression, joint function, the occurrence of low-energy fractures, thrombotic events, etc.).   Objective: to study the structure of comorbid diseases and adverse events that occurred in patients with RA over the period of long-term prospective follow-up, to study the impact of these events on the dynamics of the functional status and working capacity of patients.   Materials and methods. Аn open, cohort, prospective, long-term non-interventional study included 103 women with a definite diagnosis of RA (mean age 63.5 ± 8.3 years, follow-up period 8,5 ± 1,3 years). At baseline and in dynamics, standard laboratory and X-ray examinations were carried out.   Results and discussion. There was a decrease in the DAS28 index and the number of patients with high or moderate activity [from 82 (85 %) to 67 (69 %), p = 0.02] against the background of an increase in the number of patients with remission or low activity [from 15 (15 %) to 30 (31 %), p = 0.012], at the same time there was an increase in the number of patients with ankylosis of joints [from 25 (24 %) to 41 (40 %), p = 0.017], functional class III [from 3 (3 %) to 15 (15 %), p=0.004], concomitant diseases [from 81 (79 %) to 94 (91 %), p = 0.015], thrombotic events [from 7 (7 %) to 18 (17 %), p = 0.027]. In 43 (42 %) patients 55 low-energy fractures were registered, in 24 (56 %) of them fractures occurred for the first time and in 19 (44 %) – repeatedly.   Conclusion. As the prospective long-term follow-up shows, despite the decrease in RA activity, the number of patients with ankylosis, joint dysfunction and concomitant diseases increased. In the structure of concomitant diseases coronary heart disease and arterial hypertension dominated. A high incidence of thrombotic events, repeated and first-time low-energy fractures was noted. The number of disabled patients increased fivefold.   Коморбидные заболевания и другие неблагоприятные события, возникающие у больных ревматоидным артритом (РА), негативно влияют на исходы РА (рентгенологическое прогрессирование, функциональные нарушения, низкоэнергетические переломы, тромботические события и др.).   Цель исследования – изучить структуру коморбидных заболеваний и других неблагоприятных событий, произошедших за время проспективного наблюдения, их влияние на динамику функционального статуса и трудоспособности больных РА.   Материал и методы. В открытое когортное проспективное многолетнее неинтервенционное исследование включено 103 женщины с достоверным диагнозом РА (средний возраст – 63,5 ± 8,3 года, длительность наблюдения – 8,5 ± 1,3 года). Исходно и в динамике проведено общепринятое лабораторное и рентгенологическое обследование.   Результаты и обсуждение. Выявлено снижение индекса DAS28 и числа больных с высокой или умеренной активностью [с 82 (85 %) до 67 (69 %), р = 0,02] на фоне увеличения числа пациенток с ремиссией или низкой активностью [с 15 (15 %) до 30 (31 %), р = 0,012], в то же время возросло число больных с анкилозом суставов [с 25 (24 %) до 41 (40 %), р = 0,017], III функциональным классом [с 3 (3 %) до 15 (15 %), р = 0,004], коморбидными заболеваниями [с 81 (79 %) до 94 (91 %), р = 0,015], тромботическими событиями [с 7 (7 %) до 18 (17 %), р = 0,027]. У 43 (42 %) больных зарегистрировано 55 низкоэнергетических переломов, у 24 (56 %) из них переломы возникли впервые и у 19 (44 %) – повторно.   Заключение. Как показало многолетнее проспективное наблюдение, несмотря на снижение активности РА, увеличилось число больных с анкилозом, нарушением функции суставов и коморбидными заболеваниями, в структуре которых преобладали ишемическая болезнь сердца и гипертоническая болезнь. Отмечена высокая частота тромботических событий, повторных и впервые произошедших низкоэнергетических переломов. Количество нетрудоспособных пациенток возросло в 5 раз
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