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Influenza is an acute respiratory infection, mainly affecting the respiratory tract (often the trachea), with a tendency to develop symptoms rapidly and in most cases not requiring hospitalization. All acute respiratory infections are non-specific, with symptoms of intoxication, catarrhal symptoms (nasal congestion, rhinorrhoea, sore throat or pharyngeal discomfort), fever and cough. Improvement and widespread implementation of molecular methods to identify respiratory pathogens has led to the establishment of a higher frequency of co-infections. A literature review of the frequency of influenza co-infections is presented. Clinical cases of monoinfluenza and co-infections of influenza and respiratory syncytial infection are described, demonstrating the antagonistic effect of the two viruses on the course of the disease. In the first case, the patient, 1 year 1 month old, was hospitalised with a fever of 39 ºC in a moderate condition. A nasopharyngeal swab showed RNA of influenza A virus by PCR and was diagnosed with influenza. In the second case, the patient, 2 years old, at the beginning of the disease complained of an increase in body temperature to 38.7 ºC, cough, and difficulty in nasal breathing. On admission, the patient was in moderate condition with a body temperature of 36.6 ºC, clear consciousness and well-being. On auscultation, breathing in the lungs was rigid, single moist rales, scattered on both sides. A nasopharyngeal swab showed RNA of influenza A virus and respiratory syncytial virus by PCR. A viral acute respiratory infection of combined etiology and acute bronchitis was diagnosed. In the third case, a 14-year-old patient presented with complaints of fever up to 39 ºC, headache, weakness, muscle pain, dry cough. The condition was of moderate severity. The diagnosis of influenza A was confirmed by a rapid test for influenza A/B/C. In the treatment and prevention of both monoinfection and co-infections of influenza and other viruses, these clinical examples demonstrate the effectiveness of oseltamivir. These clinical examples highlight some key parameters: respiratory co-infections change the typical clinical picture of the disease, making it difficult to clinically diagnose the infection, highlighting laboratory diagnosis, which in turn facilitates rapid verification of the diagnosis and timely prescription of adequate therapy.

Aim To study the relationship between monomeric C-reactive protein (mCRP) and the progression of asymptomatic carotid atherosclerosis in patients with a moderate risk for cardiovascular diseases (CVD) as assessed with the SCORE model.Material and methods The study included 80 men and women aged 53.1±5.8 years assigned to the category of a moderate risk for CVDs by the SCORE model with a low-density lipoprotein cholesterol (LDL-C) level of 2.7–4.8 mmol/l and asymptomatic, hemodynamically insignificant (Results A concentration of LDL-C Conclusion According to the results of 7-year follow-up, the plasma concentration of mCRP was significantly higher in patients with an increased number of ASPs than in patients without this increase. An increased level of mCRP may indicate a higher inflammatory risk of CVD.

Chickenpox is an acute viral infection which is a serious public health problem. According to the World Health Organization, there are 4,2 million severe forms of disease requiring hospitalization and 4,200 deaths annually. The CP cause is DNA-containing herpesvirus 3, Varicella-zoster. The first symptoms of the disease appear after the incubation period, which lasts from 10 to 21 days, and are manifested by fever, malaise and the appearance of a characteristic rash in the form of small vesicles with transparent content on the skin and mucous membranes. The vesicles are progressively covered with crust, which disappears within 7–10 days. Chicken pox is more frequent in the mild and moderate form, but it may develop severe forms, atypical course, complications (most often bacterial skin infections and lesions of the nervous system are registered in children (more often – chicken encephalitis), and in adults - pneumonia). Vaccinal prevention is the most effective and scientifically proven method of infection control, and chickenpox currently belongs to such infections. The currently used chickenpox vaccines were developed in the mid 1970s, used in some countries from the mid 1980s, and from the early 1990s began to be used in routine immunization programmes in leading countries. Since then, their safety and immunogenicity as well as high efficiency of routine chickenpox vaccine prevention in both healthy and high-risk individuals have been proved. Accumulated experience has shown that a vaccine can reduce the number of cases and the frequency of hospitalizations and deaths when mass immunization is carried out.

Aim. To evaluate the common carotid artery (CCA) intima-media complex thickness (IMT) and the presence of atherosclerotic plaques (ASP) in young people with abdominal obesity who don’t have metabolic syndrome and those who have it, as well as a link between fat depots (perivascular, visceral, subcutaneous, epicardial) and CCA IMT. Materials and methods. The study included 145 people aged 18-45 years. They were divided into 3 groups: group 1 (n=18) - healthy volunteers (control group), group 2 (n=48) - patients with abdominal obesity and no more than one additional risk factor (metabolically healthy) and group 3 (n=79) - patients with metabolic syndrome. In persons included in the study the following parameters were measured: the height, weight, body mass index, waist circumference, fasting blood glucose, glucose tolerance, uric acid, lipid profile, insulin and the insulin resistance index (HOMA-IR). They also were given a 24-hour blood pressure monitoring, and an evaluation of CCA IMT, a presence of ASP in the carotid arteries and a maximum degree of internal carotid stenosis was performed using the duplex scan of brachiocephalic arteries. Computed tomography (Aquilion One Vision Edition, Toshiba, Japan) with determining subcutaneous, visceral, perivascular, epicardial fat was performed, and the ratio of subcutaneous to visceral fat was calculated. Results. Significant differences in mean CCA IMT were revealed only between persons of group 1 and group 3 (p=0.025), while the median of IMT were within normal ranges (group 1: 0.49 [0.46; 0.56]; group 2: 0.53 [0.49; 0.59]; group 3: 0.56 [0.52; 0.62]). Significant differences in a distribution of individuals with increased IMT between groups were also not revealed. However, the proportion of individuals with ASP was significantly higher in group 2 compared with group 1 (p

Aim of the study Determine in prospective observation study the factors of progression of atherosclerosis in pts with rheumatoid arthritis (RA) during 3 yrs. Matherial and methods This prospective study included 124 patients with RA and suspected ischemic heart disease (IHD), the average age was 58 [52; 63] years. Follow-up period was 3 years (37.5 moths). All RA pts were examined and had treatment, according to European and National guidelines for the diagnosis and treatment of stable CAD (2013) and EULAR for RA (2016). Carotid ultrasound and coronary angiography were also completed. In course of all RA pts the following risk factors were assessed: arterial hypertension (AH), smoking, overweightbody (BMI), heredity for cardiovascular diseases (CVD), diabetes mellitus (DM), dyslipidemia (DLP). The laboratory studies were: CBC and total cholesterol (TC), HDL-C, LDL-C, TG, highly sensitive C-reactive protein (hs-CRP), RA detected activity markers: rheumatoid factor (RF), antibodies to cyclic citrullinated peptide (ACCP), index DAS28. Pro-inflammatory cytokines -interleukin (IL) -1-beta, IL-6, tumor necrosis factor alpha (TNF alpha) were assessed in single RA pts once after 3 years of observation. Results The median duration of RA in inclusion in the study was 11 years, the DAS28 index was 3.8 points (middle degree of activity). DLP was detected in 41% RA pts. DM was in 13% pts. In RA pts, initially atherosclerotic plaques with stenosis of the carotid arteries (CA) 20% or more in 94 pts (77%) were revealed, in 3 of them CA stenosis exceeded 50%. 90 RA pts (72%) were examined again. 21 pts had signs of progressing atherosclerosis marked in CA and/or coronary arteries: 12 (13%) RA patients had only progression of atherosclerosis of CA, 7 (8%) - only progression of atherosclerosis of coronary arteries, 2 (2%) had both progression CA and coronary arteries. There are 2 formed subgroups of RA pts: Gr1 with the progression of atherosclerosis (n=21) and Gr 2 without progression of atherosclerosis (n=69). There are no differences between groups of risk factors of atherosclerosis development age, AH, BMI, lipids,TG, hs CRP, index DAS28. Following rick factors: smoking (n=12 (57%) vs n=21 (30%)), heredity for CVD (n=11 (52%) vs n=17 (25%)), RA duration (13 yrs [10; 18] vs 12 years [6; 18]) were often revealed among pts of Gr 1. All differences p>0.05 Immunological data TNF alfa level, (8,08 [2,3; 8,44] pg/ml vs 1,22 [0,13; 8,00] pg/ml), IL-1β level, 3,97 [3,56; 4,10] pg/ml vs 3,52 [0,30; 4,53] pg/ml, and IL-6 level 3,50 [2,92; 5,76] pg/ml vs 2,52 [0,92; 4,36] pg/ml were significant higher in Gr1 than in Gr2. All differences was p>0.05. Conclusion The progression of atherosclerosis in RA with a low and moderate degree of activity of the disease occurs despite antirheumatic and lipid-lowering therapy. The development of atherosclerosis in this disease is defined by lipid, inflammatory and immunological disorders. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Russion National Cardiology Research Center Ministry of Health of Russion Federation

В экспериментах на 10 мужчинах4добровольцах в возрасте 5060 лет без выраженной сердечно4сосудистой патологии исследовали влияние относительно кратковременных (по 3050 мин. в день) физических упражнений, сопряженных с повышением напряжения сдвига в ПА, на величину эндотелий4зависимой вазодилатации этой артерии, вызываемой увеличением в ней скорости кровотока. В контрольном периоде на обеих руках испытуемых регистрировали эндотелий4зависимую дилатацию ПА, вызываемую увеличением кровотока в период реактивной гиперемии, следующей за окклюзией, длительностью 5 мин. После 4 дней, в течение которых каждый испытуемый периодически увеличивал кровоток в сосудах только левой руки, ритмически сжимая ею в течение 3050 мин. в сутки резиновый кистевой эспандер, вновь измеряли поток4зависимую вазодилатацию (ПЗВД) на обеих руках и сопоставляли результаты с данными контрольных измерений. В контрольных измерениях реакции ПА обеих рук на повышение кровотока, вызванного окклюзией, были практически одинаковы (4,98 0,3 на левой руке и 5,07 0,6 на правой руке). После 44дневного цикла упражнений левой рукой величина ПЗВД на правой руке не изменилась (p 0,5), а на левой руке достоверно выросла у всех испытуемых, в среднем до 7,84 0,82 (p 0,01). Таким образом, показано, что даже кратковременные физические упражнения, сопряженные с увеличением действующего на стенку артерий напряжения сдвига, заметно улуч4 шают способность эндотелия расслаблять сосудистые гладкие мышцы при увеличении кровотока. Этот результат подтверждает представление о том, что трансформация эндотелиального гликокаликса под действием напряжения сдвига улучшает механоцептивную функцию эндотелия.

At present chaotic vibrations are the one of the most interesting and explored subjects in nonlinear dynamics. Particularly the routes to chaos in non-smooth dynamical systems are of the special scientists’ interest. Quasiperiodic route to chaos in nonlinear non-smooth discontinuous 2-DOF vibroimpact system is studied in this paper. In narrowfrequency range different oscillatory regimes have succeeded each other many times under very small control parameter varying. There were periodic subharmonic regimes - chatters, quasiperiodic, and chaotic regimes. There were the zones of transition from one regime to another, the zones of prechaotic and postchaotic motion. The hysteresis effects (jump phenomena) occurred for increasing and decreasing frequencies. The chaoticity of obtained regime has been confirmed by typical views of Poincare map and Fourier spectrum, by the positive value of the largest Lyapunov exponent, and by the fractal structure of Poincare map.

The study of dynamical systems chaotic behavior and their routes to chaos was in particular attention at recent years. These phenomena study in non-smooth dynamical system is of the special scientists’ interest. We apply the Continuous Wavelet Transform (hereinafter - CWT) to investigate the intermittent route to chaos, boundary crisis, and transitional regimes under quasi-periodic route to chaos in strongly nonlinear non-smooth discontinuous 2-DOF vibroimpact system. We show that CWT application is very useful to observe the intermittency, chaos and transitional regimes. It allows one to detect and to determine these phenomena with great confidence, reliability, and clearness.

Purpose: to compare rates of access site complications at early (after 4 hours) and traditional (after 24 hours) removal of a compression bandage after diagnostic transradial (TR) coronary angiography (CA) in patients not receiving anticoagulants.Materials and methods. We included into this study 392 patients (mean age 63±8.7 years, 62.8% men) who underwent transradial coronary angiography. Patients were divided into 2 groups. In group 1 patients (n=221) compression bandage was removed from puncture site in 4 hours after procedure with subsequent control of radial artery patency using presence of pulse metric curve during ulnar artery compression (the reverse Barbeau test with pulse oximeter). In patients of group 2 (n=171) compression band was removed after 24 hours. In both groups control of radial artery patency was carried out after 24 hours using the reverse Barbeau test. Upon detection of radial artery occlusion (RAO) ultrasound imaging of the forearm arteries was performed.Results. No RAO was detected in group 1 while in group 2 number of detected RAO was 15 (8.8%) (р0.05).Conclusion. Compared with traditional method early removal of compression bandage after TR CA was associated with lower rate of RAO.

Takayasu arteritis belongs to the group of systemic vasculitis with a predominant lesion of large - caliber vessels and the development of stenosis of their lumen. In world practice, to establish the diagnosis of arteritis Takayasu apply the criteria proposed by the American College of rheumatologists. Currently, there are no randomized clinical trials related to the disease, and the diagnosis and treatment of patients are based on a number of small studies, a series of clinical cases and expert opinion. The described clinical observation of a patient with Takayasu arteritis is of interest in connection with the detected atrial myocarditis during MRI diagnosis of the heart with contrast, which allows us to discuss the feasibility of this imaging technique in complex and doubtful cases.Артериит Такаясу относится к группе системных васкулитов с преимущественным поражением сосудов крупного калибра и развитием стенозирования их просвета. В мировой практике для установления диагноза артериита Такаясу применяют критерии, предложенные Американской коллегией ревматологов. В настоящее время отсутствуют рандомизированные клинические испытания, касающиеся этого заболевания, и диагностика и лечение пациентов основаны на данных ряда небольших исследований, серии клинических случаев и мнении экспертов. Описанное клиническое наблюдение пациентки с артериитом Такаясу представляет интерес в связи с выявленным миокардитом предсердий при проведении МРТ-диагностики сердца с контрастированием, что позволяет обсуждать вопрос о целесообразности выполнения данной визуализирующей методики в сложных и сомнительных случаях.

Aim To determine in a prospective study factors of progressive atherosclerotic lesion of blood vessels in patients with rheumatoid arthritis (RA).Material and methods This prospective study included 124 patients with RA and suspected ischemic heart disease (IHD) and 30 patients with IHD (comparison group) aged 58 [52; 63] years. On enrollment to the study and at 3 years of follow-up, all patients underwent clinical and instrumental examination according to European and Russian guidelines for diagnosis and treatment of stable IHD (2013), including coronography as indicated. For all RA patients of the comparison group, risk factors (RF) were evaluated, including arterial hypertension, smoking, excessive body weight, family history of cardiovascular diseases (CVD), diabetes mellitus, and dyslipidemia. The following laboratory data were evaluated: blood count; biochemistry, including total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), rheumatoid factor (RhF), cyclic citrullinated peptide antibodies, and high-sensitivity C-reactive protein (hsCRP). Proinflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF- α), were measured in RA patients once, at 3 years of follow-up.Results Incidence of FRs for CVD was similar in RA patients and in the comparison group. Median RA duration before inclusion into the study was 11 years, and median DAS28 index score was 3.8. Incidence of dyslipidemia due to increased TC, LDL-C, and HDL-C was higher for RA patients at baseline. The LDL-C goal (vs. 0.16 mg/dl; pvs. 11.5 mm/h; p50%. Patients with RA frequently had unchanged or slightly changed coronary arteries (CA) (47% of patients), and less frequently they had hemodynamically significant multi-arterial coronary atherosclerotic lesions (7 % vs. 57 % of patients in comparison group). At 37.5 months, 21 (23 %) of 94 RA patients had progressive atherosclerosis in CA and/or CTA; 12 (13 %) RA patients had only progressive CA atherosclerosis; 7 (8 %) had only progressive CTA atherosclerosis; and 2 (2 %) had simultaneous progression of CA and CTA atherosclerosis. Two groups of RA patients were formed, with the progression of atherosclerosis (n=21) and without the progression of atherosclerosis (n=69). RFs for the development/progression of atherosclerosis in RA patients included smoking, family history of CVD, and duration of the disease. Levels of lipids did not differ. Levels of proinflammatory cytokines (IL-1β, IL-6, TNF-α) were higher in RA patients with progressive atherosclerosis. No effects of the anti-rheumatic therapy on the progression of atherosclerosis were observed.Conclusion Progression of atherosclerosis in RA remains in disease with low and moderate activity during the anti-rheumatic and hypolipidemic treatment. The development of atherosclerosis in RA is determined by lipid, inflammatory, and immune disorders.

Background. Despite the enormous benefits of radial access, this route is associated with a risk of radial artery occlusion (RAO). Objective. We compared the incidence of RAO in patients undergoing transradial coronary angiography and intervention after short versus prolonged hemostasis protocol. Also we assessed the efficacy of rescue 1-hour ipsilateral ulnar artery compression if RAO was observed after hemostasis. Material and Methods. Patients referred for elective transradial coronary procedures were eligible. After 6 F radial sheath removal, patients were randomized to short (3 hours) (n = 495) or prolonged (8 hours) (n = 503) hemostasis and a simple bandage was placed over the puncture site. After hemostasis was completed, oximetry plethysmography was used to assess the patency of the radial artery. Results. One thousand patients were randomized. Baseline characteristics were similar between both groups with average age 61.4 ± 9.4 years (71% male) and PCI performed on half of the patients. The RAO rate immediately after hemostasis was 3.2% in the short hemostasis group and 10.1% in the prolonged group ( p < 0.001 ). Rescue recanalization was successful only in the short group in 56.2% (11/19); at hospital discharge, RAO rates were 1.4% in the short group and 10.1% in the prolonged group ( p < 0.001 ). Conclusion. Shorter hemostasis was associated with significantly less RAO compared to prolonged hemostasis. Rescue radial artery recanalization was effective in > 50%, but only in the short hemostasis group.

Aim Immune and inflammatory reactions contribute to the progression of atherosclerosis. The walls of the different arteries and segments of the arteries have heterogeneous haemodynamic and histological features. We aimed to explore the relationship between the circulating T-cell subsets and the abundance of carotid atherosclerosis in different segments of carotid arteries. Methods 70 patients underwent ultrasound duplex scanning to determine the degree of stenosis of the common carotid artery (CCA), the CCA bifurcation or the internal carotid artery (ICA). The blood frequencies of T-, B-, NK-cells, regulatory T cells (Treg), activated T-helpers (Th), IL10-producing Th, Th1 and Th17, as well as blood levels of hsCRP, sCD25, IL10 and IL17a were assessed. Results The frequencies of Th17 were increased in patients with ICA stenosis >35% and >50% vs. patients with ICA stenosis 50%). BMI positively correlated with the CCA bifurcation stenosis degree (r = 0.33, p < 0.05). Conclusion The severity of ICA stenosis can be associated with the circulating Th17 level., Cell biology; Immunology; Cardiology; Diagnostics; Atherosclerosis; Inflammation; Carotid arteries; Ultrasound; T-helpers 17.

Aim. To study predictors of radial artery occlusion (RAO) and ways to prevent it after interventions using radial access.Material and methods. The study consisted of prospective and retrospective parts. The total number of included patients was 2284. Patients undergoing interventions by radial access in various medical organizations were retrospectively considered. The prospective study included 1284 patients who were subject to interventional treatment. Patients were randomized into two groups as follows: in group 1, hemostasis was performed within 4 hours, in group 2 — >6 hours. All patients underwent a bedside Barbeau test with a pulse oximeter and an ultrasound of access arteries to determine the radial artery patency/occlusion.Results. The RAO rate in the retrospective part was 21,8%, while in the prospective one — 10,1% with long-term hemostasis and 1,4% with short-term hemostasis (pConclusion. The main predictors of RAO were type 2 diabetes, an increase in hemostasis duration, female sex, smoking, and the artery-to-introducer diameter ratio. Taking statins, anti-ischemic and antihypertensive agents does not have a protective effect on RAO rate.

Aim: to study carotid plaques structure in patients with acute coronary syndrome by ultrasound duplex scanning. Materials and methods. We included in this study143 patients with acute coronary syndrome (ACS) aged 32-83 years and 28 patients with documented coronary heart disease (CHD) aged 46-83 years. Duplex scanning of carotid arteries was carried out with Philips iU22 ultrasound system and L9-3 linear array transducer. Atherosclerotic plaques in CCA, CCA bifurcation, and ICA from right and left side were investigated. Off-line analysis of B-mode images and plaque gray scale median (GSM) was performed with computer semiautomated workstation MultiVox. Results. 378 plaques of ACS and 59 plaques of CHD patients were studied. We assessed traditional (heterogenous structure, hypoechogenic component, irregular plaque surface) as well as additional (positive remodeling, “layered” structure of plaque, local calcification) criteria of plaque instability. In ACS compared with CHD group there were more plaques with hypoechogenic component (43.4 and 28.8%, p=0.0459), heterogenous structure (77.8 and 64.4%, p=0.0327), irregular surface including irregularities more than 2.0 mm (22.5 and 6.8%, p=0.0048, respectively). There was significant difference in “layered” structure (55.7 and 35.8%, p=0.0011) and insignificant difference in positive remodeling (16.3 and 7.5%, p=0.06, respectively). There were no differences of GSM value (53.1 and 57.2, p=0.24) and local calcification (23.2 and 24.5%, p=0.23, respectively). Conclusion. In our study ultrasound duplex scanning revealed that signs of plaque instability in carotid arteries in patients with ACS were more frequent than in patients with stable CHD. The newly introduced parameter “layered” structure of atherosclerotic plaque was found to be most significant.

Radial access has great advantages in terms of the frequency of complications, but it has one specific complication - radial artery occlusion (RAO). This complication often does not manifest itself in any way; however, it limits the use of access for the future interventions. Aim To compare methods of short and traditional hemostasis and to identify the main predictors of RAO after radial access. Materials and methods During the period from 2012 to 2018, 2000 patients were included in the study, which consisted of two parts: prospective - 1000 patients who underwent coronary angiography and percutaneous coronary intervention (PCI) with stable coronary artery disease, and retrospective part of the study, which included 1000 patients admitted for PCI from other clinics. In a prospective study, patients were divided into two groups: after coronary angiography and PCI, respectively (n=500 in the coronary angiography group and n=500 in the PCI group), and then randomized. Hemostatic bandages in the first group of patients (n=250) were removed after 12–24 hours, in the second group (n=250) - after 4±1 hours. When the occlusion of the radial artery was detected, all patients underwent an hour-long compression of the ipsilateral ulnar artery to recanalize acute RAO. Results The frequency of RAO in the retrospective part of the study was 21.8%. The frequency of RAO in the prospective part of the study was 10.2% with a traditional time hemostasis and 1.4% with a short-time compression (P Table 1. Predictors of RAO Variables Odds ratio 95% Confidential interval Significance, P Traditional-time hemostasis 8.78 4.2–21.5 Conclusion Careful examination of the patient for detecting RAO before and after interventions is essential. Short hemostasis with compression of the ipsilateral ulnar artery reduce the frequency of RAO. For short-time hemostasis, special attention should be paid to patients after PCI and with low BMI, as far as these factors are associated with a greater risk of bleeding after removal of the compression bandage.

Dynamic behaviour of strongly nonlinear non-smooth discontinuous vibroimpact system isstudied. Under variation of system parameters we find the discontinuous bifurcations that are the dangerous ones. 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. We 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 is their moduli becoming more than unit by jump. We also learn the bifurcation picture change when the impact between system bodies became the soft one due the change of system parameters. This paper is the continuation of the previous works. Изучается динамическое поведение нелинейной негладкой разрывной виброударной системы. При изменении системных параметров мы находим разрывные бифуркации, которые являются опасными. Это явление уникально для негладких систем с разрывной правой частью. Вибраударную систему с двумя степенями свободы мы исследуем численным методом продолжения по параметру вместе с методами стрельбы и Ньютона-Рафсона. Удар моделируется нелинейной силой контактного взаимодействия в соответствии с контактным законом Герца. Разрывные бифуркации определяются по значениям мультипликаторов Флоке. Изучается также изменение бифуркационной картины, когда удар между телами становится мягким.

This paper discusses bifurcations in nonlinear vibroimpact system. It is a discontinuous dynamical system. We were studying stability and bifurcations in specific two-body two-degree-of-freedom vibroimpact system by numerical parameter continuation method. We adapted parameter continuation technique for this system. Theoretical basis for dynamic characteristics composition was presented in [1]. The instability zones and bifurcation points for loading curves were determined in [1] under excitation amplitude variation. In this paper we investigate the instability zones and bifurcation points under variation of excitation frequency when we consider the frequency-amplitude response. We have observed phenomena unique for nonsmooth systems with discontinuous right-hand side: discontinuous bifurcation points where set-valued Floquet multipliers cross the unit circle by jump. At these points monodromy matrix is changed by jump too. We also have observed chattering regimes leading to chaos.

Dynamic behaviour of contact impact forces in strongly nonlinear discontinuous vibroimpact system is studying. Contact impact force is one of the most significant vibroimpact system characteristics. We investigate the 2-DOF vibroimpact system by numerical parameter continuation method in conjunction with shooting and Newton-Raphson methods. We simulate the impact by nonlinear contact interactive force according to Hertz’s contact law. This paper is the continuation of the previous works [1,2]. We have determined the instability zones and bifurcations points for loading curves [1] and frequency-amplitude response [2] under variation of excitation amplitude and frequency. In this paper we investigate the behaviour of contact forces at bifurcation points particularly at discontinuous bifurcation points where set-valued Floquet multipliers cross the unit circle by jump that is their moduli becoming more than unit by jump. It is phenomenon unique for nonsmooth systems with discontinuous right-hand side. We observe also the contact forces increase at nT -periodical multiple impacts regimes. We also learn the change of contact forces behaviour when the impact between system bodies became the soft one due the change of system parameters.

The study was aimed at assessing the dynamics of asymptomatic atherosclerosis of carotid arteries (CA) depending upon the achieved level of low-density lipoprotein cholesterol (LDLC) in patients with moderate total risk by the SCORE scale. We followed up a total of eighty-two 40-to-65-year-old patients with the LDLC level above 2.6 mmol/l, being at moderate total risk by the SCORE scale and having symptom-free atherosclerosis of the extracranial portion of brachiocephalic arteries (up to 50% narrowing of their lumen) as diagnosed by duplex scanning. The patients were randomly divided into two groups. Group One patients (n=41) received therapy with atorvastatin in order to achieve the LDLC level less than 1.8 mmol/l. Group Two patients (n=41) were treated in order to achieve the LDLC level below 2.6 mmol/l. At 12 months of follow up we compared the dynamics of carotid atherosclerosis (change in the number, total height, structure, echogenicity, as well as the state of the surface of atherosclerotic plaques, alteration of the thickness of the CA intima-media complex). Group Two patients were found to have an increase in the number and average sum of the heights of atherosclerotic plaques. An increase of the maximum thickness of the intima-media complex of the wall of the right and left CA was more pronounced as compared with that in Group One patients. Aggressive hypolipidemic therapy aimed at achieving the LDLC level below 1.8 mmol/l turned out to be more effective in slowing down the progression of asymptomatic carotid atherosclerosis in patients with moderate cardiovascular risk than therapy targeted at achieving the LDLC level below 2.6 mmol/l.

to study carotid plaques structure in patients with acute coronary syndrome by ultrasound duplex scanning.We included in this study143 patients with acute coronary syndrome (ACS) aged 32-83 years and 28 patients with documented coronary heart disease (CHD) aged 46-83 years. Duplex scanning of carotid arteries was carried out with Philips iU22 ultrasound system and L9-3 linear array transducer. Atherosclerotic plaques in CCA, CCA bifurcation, and ICA from right and left side were investigated. Off-line analysis of B-mode images and plaque gray scale median (GSM) was performed with computer semiautomated workstation MultiVox.378 plaques of ACS and 59 plaques of CHD patients were studied. We assessed traditional (heterogenous structure, hypoechogenic component, irregular plaque surface) as well as additional (positive remodeling, "layered" structure of plaque, local calcification) criteria of plaque instability. In ACS compared with CHD group there were more plaques with hypoechogenic component (43.4 and 28.8%, p=0.0459), heterogenous structure (77.8 and 64.4%, p=0.0327), irregular surface including irregularities more than 2.0 mm (22.5 and 6.8%, p=0.0048, respectively). There was significant difference in "layered" structure (55.7 and 35.8%, p=0.0011) and insignificant difference in positive remodeling (16.3 and 7.5%, p=0.06, respectively). There were no differences of GSM value (53.1 and 57.2, p=0.24) and local calcification (23.2 and 24.5%, p=0.23, respectively).In our study ultrasound duplex scanning revealed that signs of plaque instability in carotid arteries in patients with ACS were more frequent than in patients with stable CHD. The newly introduced parameter "layered" structure of atherosclerotic plaque was found to be most significant.

Background To date, there have been no studies evaluating the effect of isolated lipoprotein(a) (Lp(a)) lowering therapy on carotid atherosclerosis progression. Methods We enrolled 30 patients who had coronary heart disease (CHD) verified by angiography, Lp(a) level ≥50 mg/dL, and low density lipoprotein cholesterol (LDL-C) level ≤2.6 mmol/L (100 mg/dL) on chronic statin therapy. Subjects were allocated in a 1:1 ratio to receive apheresis treatment on a weekly basis with immunoadsorption columns ("Lp(a) Lipopak" ® , POCARD Ltd., Russia) added to atorvastatin, or atorvastatin monotherapy. The primary efficacy end-point was the change from baseline in the mean intima-media thickness (IMT) of the common carotid arteries. Results After one month run-in period with stable atorvastatin dose, LDL-C level was 2.3 ± 0.3 mmol/L and Lp(a) – 105 ± 37 mg/dL. As a result of acute effect of specific Lp(a) apheresis procedures, Lp(a) level decreased by an average of 73 ± 12% to a mean of 29 ± 16 mg/dL, and mean LDL-C decreased by 17 ± 3% to a mean of 1.8 ± 0.2 mmol/L. In the apheresis group, changes in carotid IMT at 9 and 18 months from baseline were −0.03 ± 0.09 mm (p = 0.05) and −0.07 ± 0.15 mm (p = 0.01), respectively. In the atorvastatin group no significant changes in lipid and lipoprotein parameters as well as in carotid IMT were received over 18-month period. Two years after study termination carotid IMT increased by an average of 0.02 ± 0.08 mm in apheresis group and by 0.06 ± 0.10 mm in the control group (p = 0.033). Conclusion Isolated extracorporeal Lp(a) elimination over an 18 months period produced regression of carotid intima–media thickness in stable CHD patients with high Lp(a) levels. This effect was maintained for two years after the end of study. Trial Registration: Clinicaltrials.gov (NCT02133807).

The modification of the one-parameter numerical continuation method for studying the dynamics of vibroimpact systems subject to periodic external loads is proposed. The behavior of a vibroimpact double spring mass system with two degrees of freedom is analyzed in relation to the load intensity. Specific applications of the method are compared with the two impact simulation procedures: contact force on the basis of the Hertz quasistatic theory and boundary conditions using the coefficient of restitution based on the stereomechanical theory of impact. Numerical analysis results for dynamic system states with the two impact simulation procedures are presented.

On the basis of the results of numerical analysis, it is shown that the introduction of a force of contact interaction varying according to the Hertz law to the equation of motion makes it possible to model impacts between colliding bodies both under harmonic and stochastic external loads. This enables us to deduce the law of motion of the bodies in a vibroimpact system for the entire time axis, including the period of impact. We perform the numerical optimization of the parameters of the vibroimpact system by the method of gradient projection with correction of the discrepancy in constraints. The comparative analysis of the efficiency of the dynamic nonimpact dampers and shock absorbers of vibrations is presented.