Partial symmetry breaking and heteroclinic tangencies

We study some global aspects of the bifurcation of an equivariant family of volume-contracting vector fields on the three-dimensional sphere. When part of the symmetry is broken, the vector fields exhibit Bykov cycles. Close to the symmetry, we investigate the mechanism of the emergence of heteroclinic tangencies coexisting with transverse connections. We find persistent suspended horseshoes accompanied by attracting periodic trajectories with long periods

On Global Bifurcations of Three-dimensional Diffeomorphisms Leading to Lorenz-like Attractors

We study dynamics and bifurcations of three-dimensional diffeomorphisms with nontransversal heteroclinic cycles. We show that bifurcations under consideration lead to the birth of Lorenz-like attractors. They can be viewed as attractors in the Poincare map for periodically perturbed classical Lorenz attractors and hence they can allow for the existence of homoclinic tangencies and wild hyperbolic sets

Оptimization approach to the synthesis of plasma stabilization system in tokamak ITER

Synthesis of the controller of ITER plasma stabilization system is considered. Stabilization system is based on tokamak diagnostic measurements, defines the voltages in tokamak coils and has the filtering properties. Known methods of synthesis of plasma regulators are advanced by the presented optimization approach. It makes possible to meet the requirements for the dynamics of the stabilization process when considering a set of some arbitrary plasma drops and disturbances. The proposed approach evaluates the ensemble of transient processes of the closed object. Based on this estimations it is possible to use wide range of optimization techniques.Розглядається синтез регулятора для системи стабілізації плазми в токамаці ІТЕР. Система стабілізації заснована на вимірах діагностичної системи токамака, вона задає напруги в керуючих котушках і має властивості фільтрації. Відомі методи синтезу регуляторів плазми вдосконалені запропонованим оптимізаційним підходом. Це дає можливість задовольнити вимоги до якості динаміки процесу стабілізації з урахуванням різних невизначеностей в динаміці плазми, в тому числі збурень плазми. Запропонований підхід оцінює ансамбль перехідних процесів замкнутого об'єкта. На основі запропонованих оцінок можна використовувати широкий спектр методів оптимізації.Рассматривается синтез регулятора для системы стабилизации плазмы в токамаке ИТЭР. Система стабилизации основана на измерениях диагностической системы токамака, она задаёт напряжения в управляющих катушках и обладает свойствами фильтрации. Известные методы синтеза регуляторов плазмы усовершенствованы предлагаемым оптимизационным подходом. Это дает возможность удовлетворить требования к качеству динамики процесса стабилизации с учётом различных неопределённостей в динамике плазмы, в том числе возмущений плазмы. Предложенный подход оценивает ансамбль переходных процессов замкнутого объекта. На основе предложенных оценок можно использовать широкий спектр методов оптимизации

Microbiological oropharyngeal patterns in patients with different phenotypes of chronic obstructive pulmonary disease

Persistent bronchial inflammation in chronic obstructive pulmonary disease (COPD) is considered the cause of ventilation disorders and related contamination with conditionally pathogenic microorganisms; the latter can proceed and transform into a full infection, which can aggravate and exacerbate COPD. The aim of the study was to evaluate the relations between the oropharyngeal microbiota in patients with COPD and the clinical, functional, and prognostic parameters of the disease. Materials and Methods. 64 patients with COPD were included in the study; the participants were scheduled to visit our clinic on two occasions. In the first visit, their medical history was studied in detail and the major examination procedures were conducted. Those included an assessment of the respiratory function, the 6-minute walk test, the degree of dyspnea by the Medical Research Council scale, body plethysmography, the diffusion capacity of the lungs, and a chest CT scan. The second visit took place 12 months after the first one to assess the changes in the course of the disease. The result was considered negative if, in the second examination, the patient‘s condition was found more severe. Oropharyngeal samples of all patients were sequenced to identify the V3–V4 variable sites of the 16S rRNA gene. Results. It is found that the microbiological oropharyngeal patterns in COPD patients depend on the source of micro-aspiration. In addition, the changes in the oropharyngeal microbiota correlate with the severity and prognosis of the disease, as well as the patient phenotype. Based on the data obtained by sequencing parts of the 16S rRNA gene, the role of oropharyngeal microbiota in determining the course and prognosis of COPD has been elucidated. Conclusion. The presented clinical and functional characteristics associated with oropharyngeal microbiota indicate that microaspirations from other body compartments not only affect the composition of oropharyngeal microbiota in patients with COPD but also have an important prognostic significance. © 2018, Nizhny Novgorod State Medical Academy. All rights reserved

Microbiological oropharyngeal patterns in patients with different phenotypes of chronic obstructive pulmonary disease

Persistent bronchial inflammation in chronic obstructive pulmonary disease (COPD) is considered the cause of ventilation disorders and related contamination with conditionally pathogenic microorganisms; the latter can proceed and transform into a full infection, which can aggravate and exacerbate COPD. The aim of the study was to evaluate the relations between the oropharyngeal microbiota in patients with COPD and the clinical, functional, and prognostic parameters of the disease. Materials and Methods. 64 patients with COPD were included in the study; the participants were scheduled to visit our clinic on two occasions. In the first visit, their medical history was studied in detail and the major examination procedures were conducted. Those included an assessment of the respiratory function, the 6-minute walk test, the degree of dyspnea by the Medical Research Council scale, body plethysmography, the diffusion capacity of the lungs, and a chest CT scan. The second visit took place 12 months after the first one to assess the changes in the course of the disease. The result was considered negative if, in the second examination, the patient‘s condition was found more severe. Oropharyngeal samples of all patients were sequenced to identify the V3–V4 variable sites of the 16S rRNA gene. Results. It is found that the microbiological oropharyngeal patterns in COPD patients depend on the source of micro-aspiration. In addition, the changes in the oropharyngeal microbiota correlate with the severity and prognosis of the disease, as well as the patient phenotype. Based on the data obtained by sequencing parts of the 16S rRNA gene, the role of oropharyngeal microbiota in determining the course and prognosis of COPD has been elucidated. Conclusion. The presented clinical and functional characteristics associated with oropharyngeal microbiota indicate that microaspirations from other body compartments not only affect the composition of oropharyngeal microbiota in patients with COPD but also have an important prognostic significance. © 2018, Nizhny Novgorod State Medical Academy. All rights reserved

Periostin as a biomarker of allergic inflammation in atopic bronchial asthma and allergic rhinitis (A pilot study)

© 2020, Privolzhsky Research Medical University. All rights reserved. The involvement of periostin in Th2-dependent allergic inflammation has been documented. However, the significance of periostin as a biomarker of local allergic inflammation in the nasal mucosa (NM) of patients with atopic bronchial asthma (BA) and allergic rhinitis (AR) is yet to be determined. The aim of the study was to determine the presence of periostin and evaluate its role as a non-invasive marker of allergic inflammation in the nasal secretions of children with atopic BA and AR. Materials and Methods. In 43 patients aged 4–17 years with atopic BA and AR, the NM was examined using nasal video-endoscopy and (if indicated) computed tomography; the amount of periostin in the nasal secretion was determined by the enzyme immunoassay. Results. Exacerbation of AR was accompanied by a statistically significant increase in the level of periostin in the nasal secretion: up to 0.84 [0.06; 48.79] ng/mg, whereas in remission, that was 0.13 [0.00; 0.36] ng/mg; p=0.04. This value increased progressively as the severity of AR increased from 0.16 [0.00; 0.36] ng/mg in the mild course to 0.20 [0.00; 9.03] ng/mg in AR of moderate severity, and to 10.70 [0.56; 769.20] ng/mg in most severe cases; p=0.048. Hypertrophy or polyposis of the nasal and/or paranasal mucosa was detected in 34.9% (15/43) of the examined patients. The concentration of periostin in the nasal secretion was lower in children without NM hypertrophy: 0.18 [0.001; 4.30] ng/mg vs 0.78 [0.13; 162.10] ng/mg in patients with NM hypertrophy; the differences were close to statistically significant: p=0.051. The level of nasal periostin depended on the clinical form of hypertrophy in the sinonasal mucosa, reaching 0.17 [0.00; 0.32] ng/mg in children with polyposis hyperplasia of NM and 21.6 [10.70; 1516.80] ng/mg — with hypertrophy of the NM in the medial surface of the concha; p=0.02. Conclusion. Exacerbation and increased severity of AR in patients with atopic BA are accompanied by an increased level of periostin in the nasal secretion. This allows us to consider the level of nasal periostin as a biomarker of local allergic inflammation in the NM of patients with atopic BA combined with AR. Hypertrophic changes in the sinonasal mucosa are generally accompanied by an increased level of nasal periostin; specifically, this level significantly depends on the clinical form of mucous membrane hypertrophy and requires additional studies

Periostin as a biomarker of allergic inflammation in atopic bronchial asthma and allergic rhinitis (A pilot study)

The involvement of periostin in Th2-dependent allergic inflammation has been documented. However, the significance of periostin as a biomarker of local allergic inflammation in the nasal mucosa (NM) of patients with atopic bronchial asthma (BA) and allergic rhinitis (AR) is yet to be determined. The aim of the study was to determine the presence of periostin and evaluate its role as a non-invasive marker of allergic inflammation in the nasal secretions of children with atopic BA and AR. Materials and Methods. In 43 patients aged 4–17 years with atopic BA and AR, the NM was examined using nasal video-endoscopy and (if indicated) computed tomography; the amount of periostin in the nasal secretion was determined by the enzyme immunoassay. Results. Exacerbation of AR was accompanied by a statistically significant increase in the level of periostin in the nasal secretion: up to 0.84 [0.06; 48.79] ng/mg, whereas in remission, that was 0.13 [0.00; 0.36] ng/mg; p=0.04. This value increased progressively as the severity of AR increased from 0.16 [0.00; 0.36] ng/mg in the mild course to 0.20 [0.00; 9.03] ng/mg in AR of moderate severity, and to 10.70 [0.56; 769.20] ng/mg in most severe cases; p=0.048. Hypertrophy or polyposis of the nasal and/or paranasal mucosa was detected in 34.9% (15/43) of the examined patients. The concentration of periostin in the nasal secretion was lower in children without NM hypertrophy: 0.18 [0.001; 4.30] ng/mg vs 0.78 [0.13; 162.10] ng/mg in patients with NM hypertrophy; the differences were close to statistically significant: p=0.051. The level of nasal periostin depended on the clinical form of hypertrophy in the sinonasal mucosa, reaching 0.17 [0.00; 0.32] ng/mg in children with polyposis hyperplasia of NM and 21.6 [10.70; 1516.80] ng/mg — with hypertrophy of the NM in the medial surface of the concha; p=0.02. Conclusion. Exacerbation and increased severity of AR in patients with atopic BA are accompanied by an increased level of periostin in the nasal secretion. This allows us to consider the level of nasal periostin as a biomarker of local allergic inflammation in the NM of patients with atopic BA combined with AR. Hypertrophic changes in the sinonasal mucosa are generally accompanied by an increased level of nasal periostin; specifically, this level significantly depends on the clinical form of mucous membrane hypertrophy and requires additional studies. © 2020, Privolzhsky Research Medical University. All rights reserved

Extracellular matrix markers and methods for their study

The extracellular matrix (ECM) is a complex meshwork consisting mainly of proteins and carbohydrates; it is currently viewed as a key factor of tissue organization and homeostasis. In each organ, the composition of ECM is different: It includes a variety of fibrillar components, such as collagens, fibronectin, and elastin, as well as non-fibrillar molecules: Proteoglycans, hyaluronan, glycoproteins, and matrix proteins. ECM is an active tissue, where the de novo syntheses of structural components are constantly taking place. In parallel, ECM components undergo degradation catalyzed by a number of enzymes including matrix metalloproteinases. The synthesis and degradation of ECM components are controlled by mediators and cytokines, metabolic, epigenetic, and environmental factors. Currently, a large amount of evidence indicates that modifications (remodeling) of ECM play an important role in the pathogenesis of clinical conditions. This may explain the increasing interest in the markers of ECM remodeling both in health and disease. In recent years, many of the ECM markers were considered targets for diagnosing, predicting, and treating diseases. In this review, we discuss some of the currently known ECM markers and methods used for their determination. © 2019, Privolzhsky Research Medical University. All rights reserved

Маркеры состояния экстрацеллюлярного матрикса и методы их исследования (обзор)

The extracellular matrix (ECM) is a complex meshwork consisting mainly of proteins and carbohydrates; it is currently viewed as a key factor of tissue organization and homeostasis. In each organ, the composition of ECM is different: it includes a variety of fibrillar components, such as collagens, fibronectin, and elastin, as well as non-fibrillar molecules: proteoglycans, hyaluronan, glycoproteins, and matrix proteins. ECM is an active tissue, where the de novo syntheses of structural components are constantly taking place. In parallel, ECM components undergo degradation catalyzed by a number of enzymes including matrix metalloproteinases. The synthesis and degradation of ECM components are controlled by mediators and cytokines, metabolic, epigenetic, and environmental factors. Currently, a large amount of evidence indicates that modifications (remodeling) of ECM play an important role in the pathogenesis of clinical conditions. This may explain the increasing interest in the markers of ECM remodeling both in health and disease. In recent years, many of the ECM markers were considered targets for diagnosing, predicting, and treating diseases. In this review, we discuss some of the currently known ECM markers and methods used for their determination.Экстрацеллюлярный (внеклеточный) матрикс (ЭЦМ) представляет собой сложную сетчатую структуру, состоящую преимущественно из белков и углеводов, и рассматривается в настоящее время как ключевой регулятор организации тканей и гомеостаза. В каждом органе состав ЭЦМ различен, включает разнообразные фибриллярные компоненты, такие как коллагены, фибронектин и эластин, и нефибриллярные молекулы - протеогликаны, гиалуронан и гликопротеины, матриксные белки. ЭЦМ является активной структурой, в которой постоянно происходят процессы синтеза de novo структурных компонентов и параллельно - их деградации, осуществляемой преимущественно с участием ферментов, в том числе матриксных металлопротеиназ. Синтез и деградация компонентов матрикса находятся под сложным регуляторным влиянием различных медиаторов и цитокинов, метаболических, эпигенетических и средовых воздействий. В настоящее время накоплено большое количество доказательств, что изменения ЭЦМ играют важную роль при различных патологических состояниях. Этим обусловлен интерес к поиску маркеров, отражающих состояние ЭЦМ в разных органах и тканях как в физиологических условиях, так и при различных вариантах патологии. В последние годы многие из молекул ЭЦМ рассматриваются в качестве мишеней для диагностики, прогнозирования и лечения заболеваний. В данном обзоре мы систематизировали основные описанные в настоящий момент маркеры состояния ЭЦМ и используемые методы их определения