Hyperbolic chaos in self-oscillating systems based on mechanical triple linkage: Testing absence of tangencies of stable and unstable manifolds for phase trajectories

Dynamical equations are formulated and a numerical study is provided for self-oscillatory model systems based on the triple linkage hinge mechanism of Thurston -- Weeks -- Hunt -- MacKay. We consider systems with holonomic mechanical constraint of three rotators as well as systems, where three rotators interact by potential forces. We present and discuss some quantitative characteristics of the chaotic regimes (Lyapunov exponents, power spectrum). Chaotic dynamics of the models we consider are associated with hyperbolic attractors, at least, at relatively small supercriticality of the self-oscillating modes; that follows from numerical analysis of the distribution for angles of intersection of stable and unstable manifolds of phase trajectories on the attractors. In systems based on rotators with interacting potential the hyperbolicity is violated starting from a certain level of excitation.Comment: 30 pages, 18 figure

Különböző adalékok hatása az ellentétes töltésű polielektrolitok és tenzidek asszociációjára

Munkánk elsődleges célja az elektrolit ellentmondásos hatásának vizsgálata, értelmezése volt. Kutatásaink során polikation/anionos tenzid (PEI-NaDS) és polianion/kationos tenzid (PSS-DTAB, PSS-CTAB) elegyekkel foglalkoztunk. Az elektrolit egyik hatása akkor észlelhető, ha a polielektrolit-tenzid asszociátumok elkészítése során elektrosztatikusan stabilizált kolloid diszperzió képződik. Kis elektrolit koncentráció értékek esetén az elektrolit a diszperzió kinetikai stabilitását csökkenti. PEINaDS és PSS-CTAB elegyei esetén polielektrolit feleslegben egy szűk, és tenzidfeleslegben széles koncentráció tartományban keletkezik kinetikailag stabil kolloid diszperzió. Ugyanakkor PSS és DTAB elegyeinél nem sikerült tenzidfeleslegben kolloid diszperziót létrehozni. Az elektrolit másik hatása akkor figyelhető meg, ha a P/T elegyhez hozzáadott elektrolit jelentősen csökkenti a kötött tenzid mennyiségét, ugyanakkor a tenzid oldhatósága elegendően nagy marad az elektrolitoldatban. Nagy NaCl koncentráció esetén az elektrolit az egyensúlyi fázistulajdonságokra hat: nem történik asszociatív fázisszeparáció. Ezt a hatást észleltük PSS és alkil-trimetilammónium bromidok (DTAB, CTAB) elegyeiben – bizonyos sókoncentráció felett a teljes tenzidkoncentráció tartományban transzparens oldatokat kaptunk. Megállapítható, hogy az elektrolit kettős hatással bír az ellentétes töltésű polielektrolit-tenzid rendszerekre, annak minőségétől függ, hogy az elektrolit egyik, másik, vagy akár mindkét hatását látjuk. Ezek az eredmények érdekes felhasználást nyerhetnek a jövőben. Például polielektrolittenzid aggregátumok elektrosztatikusan stabilizált kolloid diszperziója lehetőséget teremt arra, hogy a részecskék hidrofób belsejükben apoláris anyagot raktározzanak, ami az elektrolit koncentráció hirtelen megemelésével felszabadítható. Más lehetőség lehet, hogy P/T nanorészecskékből álló felületi réteg létrehozásával a felület hidrofóbicitása hangolható a közeg ionerősségének változtatásával. A PEI-NaDS-PEO rendszerrel ellentétben a PSS-CTAB-Pluronic rendszerekben nem tapasztalható a semleges polimer oly mértékű adszorpciója a P/T nanorészecskék felszínére, ami sztérikus stabilizálást biztosítana a PSS-CTAB nanorészecskék kolloid diszperziójának. Az eddigi eredmények azonban nem nyújtanak elegendő információt a polimeradalék hatásáról a polielektrolit-tenzid asszociációra, ezért további vizsgálatok szükségesek

β-Катенин: структура, функции и роль в опухолевой трансформации эпителиальных клеток

The article presents the data on the structure and mechanisms of β-сatenin functioning. The basic aspects of the role of β-сatenin in malignant transformation have been studied at various tumors. Primary structure of β-catenin allows it to interact with many factors and ligands, including transcription factors, α-catenin, cadherin, Axin, Rho family GTPases, Bcl9 et al. This interaction is the base for β-catenin's intracellular multifunctioning. The review presents data on the participation of β-catenin in the mechanisms of adhesion, regulation of RNA metabolism, formation contacts with the cytoskeleton and its role in the canonical Wnt signaling pathway, marked examples pro-inflammatory and anti-inflammatory effects of β-catenin. The β-catenin involvement in malignant transformation and progression of certain tumors is not in doubt. The data on the changes in β-catenin expression in the given examples of colon cancer, prostate cancer, different forms of thyroid cancer and hepatocellular carcinoma are presented with the prospects of its use as a marker and a predictor of malignant transformation. Continued research in this area will not only make use of β-catenin as a potential predictor of malignant tumors, but also to develop approaches to targeted therapy.В обзоре представлены сведения о структуре и механизмах функционирования β-катенина, его роли в опухолевой трансформации при различных вариантах неоплазий. Первичная структура β-катенина позволяет ему взаимодействовать со многими факторами и лигандами, в т.ч. с факторами транскрипции, α-катенином, белком клеточной адгезии кадгерином, Axin, малыми ГТФазами семейства Rho, Bcl9 и др. Все это объясняет его внутриклеточную многофункциональность. Также приведены данные об участии β-катенина в механизмах адгезии, регуляции метаболизма РНК, формировании контактов с цитоскелетом, его роли как кофактора в каноническом Wnt-сигнальном пути; приведены примеры про- и противовоспалительных эффектов β-катенина. Участие β-катенина в опухолевой трансформации и прогрессии некоторых злокачественных опухолей в настоящее время не вызывает сомнений. Освещены современные представления об изменении экспрессии β-катенина при таких эпителиальных злокачественных опухолях, как рак толстой кишки, рак предстательной железы, различные варианты рака щитовидной железы, гепатоцеллюлярный рак, а также перспективах его использования как маркера и предиктора злокачественных опухолей. Продолжение исследований в данном направлении позволит не только использовать β-катенин как потенциальный предиктор злокачественных опухолей, но и разработать подходы к их таргетной терапи

Two-dimensional ferromagnetic extension of a topological insulator

Inducing a magnetic gap at the Dirac point of the topological surface state (TSS) in a three-dimensional (3D) topological insulator (TI) is a route to dissipationless charge and spin currents. Ideally, magnetic order is present only at the surface, as through proximity of a ferromagnetic (FM) layer. However, experimental evidence of such a proximity-induced Dirac mass gap is missing, likely due to an insufficient overlap of TSS and the FM subsystem. Here, we take a different approach, namely ferromagnetic extension (FME), using a thin film of the 3D TI Bi2Te3, interfaced with a monolayer of the lattice-matched van der Waals ferromagnet MnBi2Te4. Robust 2D ferromagnetism with out-of-plane anisotropy and a critical temperature of Tc ≈ 15 K is demonstrated by x-ray magnetic dichroism and electrical transport measurements. Using angle-resolved photoelectron spectroscopy, we observe the opening of a sizable magnetic gap in the 2D FM phase, while the surface remains gapless in the paramagnetic phase above Tc. Ferromagnetic extension paves the way to explore the interplay of strictly 2D magnetism and topological surface states, providing perspectives for realizing robust quantum anomalous Hall and chiral Majorana states.</p

EL ANÁLISIS DEL SISTEMA DE INFORMACIÓN DE TRANSPORTE DEL DISTRITO DE LA CIUDAD DE PODOLSK

En este artículo se llevan a cabo el análisis y la auditoría del apoyo informativo en el sistema de transporte de la ciudad más grande de la región de Moscú - Podolsk. Se examinan las características de los recursos de información, los sitios y las plataformas que proporcionan el sistema de transporte público de la ciudad. También se valoran prácticamente los aspectos funcionales y estéticos de los recursos y su utilidad en la aplicación por los ciudadanos. Se describe la conformidad de la situación real en las carreteras y su reflejo en los sitios y los recursos de información de la ciudad de Podolsk. También se examina la disponibilidad de horarios y rutas de autobuses urbanos y su conformidad con la situación real de los casos

ZrN coatings on U8 steel obtained by electrospark alloying after a concentrated solar irradiation

Structure, hardness, and tribological characteristics of electrospark coatings from ZrN-(Cr, Ni, Al₂O₃) on US steel after treatment by concentrated solar radiation (CSR) have been investigated. It is shown that the intensity of wear and factor of friction of specimens with coating after CSR are essentially less than for non-treated US steel. At changing of regime of CSR treatment from 785°C, 25.3 s to 530°C, 8.6 s and at decreasing of sliding speed at wear test from 10 m/s to 5 m/s the tribological characteristics improves. After treatment by CSR the strengthening of steel surface is observed the quenching with formation of martensite and troostite take place. At treatment by concentrated solar radiation changing in phase composition of coatings observed: before treatment by CSR the main phase in coating is ZrO₂ (cubic), after treatment by CSR the main phase is ZrNi, ZrO₂ (tetragonal) is also present.Вивчено структуру, твердість, трибологічні характеристики електроіскрових покриттів з ZrN-(Cr, Ni, Al₂O₃) на сталі У8 після обробки концентрованим сонячним випромінюванням (КСВ). Показано, що інтенсивність зношування та коефіцієнт тертя зразків з покриттям після впливу КСВ суттєво менше, ніж необробленої сталі У8. При зміненні режиму обробки КСВ від 785°С, 25,3 с до 530°С, 8,6 с та при зменшенні швидкості ковзання при випробуванні на тертя від 10 м/с до 5 м/с трибологічні характеристики покращуються. Після обробки КСВ спостерігається зміцнення поверхні сталі має місце загартування з утворенням мартенситу та трооститу. При обробці концентрованим сонячним випромінюванням спостерігаються змінення у фазовому складі покриттів: до обробки КСВ основна фаза у покритті ZrO₂ (кубічний), після обробки КСВ основна фаза ZrNi, присутній також ZrO₂ (тетрагональний).Исследованы структура, твердость, трибологические характеристики электроискровых покрытий из ZrN-(Cr, Ni, Al₂O₃) на стали У8 после обработки концентрированным солнечным излучением (КСИ). Показано, что интенсивность износа и коэффициент трения образцов с покрытием после воздействия КСИ существенно меньше, чем необработанной стали 'У8. При изменении режима обработки КСИ от 785°С, 25,3 с до 530°С, 8,6 с и при уменьшении скорости скольжения при испытании на трение от 10 м/с до 5 м/с трибологические характеристики улучшаются. После обработки КСИ наблюдается упрочнение поверхности стали происходит закалка с образованием мартенсита и троостита. При обработке концентрированным солнечным излучением наблюдаются изменения в фазовом составе покрытий: до обработки КСИ основная фаза в покрытии ZrO₂ (кубический), после обработки КСИ основная фаза ZrNi, присутствует также ZrO₂ (тетрагональный)

Assessment of epidemiological situation on hemorhhagic fever with renal syndrome around the world and in Russia, forecast for 2020

© 2020 Russian Research Anti-Plague Institute. All rights reserved. Objective of the review is to characterize the nature of epidemiological situation on HFRS around the world and to conduct a comparative analysis of intensity and dynamics of the epidemiological process in the Russian Federation by Federal Districts, as well as make forecast for 2020. The analysis of the epidemiological situation is based on the materials of the official websites of healthcare organizations in the USA and Europe, WHO, the data from operational monitoring carried out by the reference center for HFRS monitoring “Kazan Research Institute of Epidemiology and Microbiology”, materials provided by the Rospotrebnadzor Institutions in the constituent entities of the Russian Federation. The analysis included all administrative territories of the Russian Federation. Statistical processing was carried out by standard methods of variation statistics applying Excel software. The epidemiological situation on hemorrhagic fever with renal syndrome around the world and in Russia remains tense. In the Russian Federation, epidemically active foci are located in the European part of the country, in Western Siberia and in the Far East. Infections over the period of 2010–2019 were registered in 8 federal districts of the Russian Federation, in 58 constituent entities. However, the incidence distribution across the territory of the country was differential. In 97 % of the cases, the incidence was recorded in the European part of Russia. In the Volga Federal District, HFRS incidence amounted to 82.16 % of the total incidence recorded on the whole in Russia. High incidence rates are also recorded in the Central Federal District (CFD). Over the past 10 years (2010–2019), there has been an increase in the incidence of HFRS in the Central and North-West Federal Districts, and a decrease in the incidence in the Ural and Far Eastern Federal Districts. Varying degree of anthropogenic impact on the natural HFRS foci and climate change manifested in increased ambient air temperatures are of great importance for the spread of HFRS over the past decade. At the end of the review the forecast of the development of the epidemiological situation on HFRS in the Russian Federation for 2020 is presented

Morphological substantiation of laparoscopic suturing of stomach ulcer with formation of a covered perforation

Objective. Morphological substantiation of laparoscopic suturing of gastric ulcer with formation of a covered perforation. Material and methods. To analyze morphological tissue reaction in surgical area, we used 12 Chinchilla rabbits. All animals were divided into 2 groups by 6 animals. The main group enrolled rabbits undergoing suturing of perforated gastric ulcer with formation of a covered perforation by anterior stomach wall. In the control group, gastric perforation was sutured by conventional double-row suture. For histological analysis, 2 animals in each group were withdrawn from the experiment after 7, 14 and 21 days. We excised gastric wall within the area of perforation closure. Morphological data on healing process were compared between both groups. Results. Stomach deformation after 7 days was more severe in the main group compared to simple suturing. However, these dif- ferences were absent after 21 days. Morphological analysis revealed postoperative transmural necrosis after 7 days. Signs of early epithelialization were more obvious in the main group. After 21 postoperative days, we observed almost completely restored dif- ferentiation of stomach wall layers in both groups of animals. © 2022, Media Sphera Publishing Group. All rights reserved

Review of hantavirus infections in the world, epidemiological situation on hemorrhagic fever with renal syndrome in the Russian Federation in 2020 and a forecast for 2021

The review used the data from operational monitoring carried out by the Reference Center for Monitoring over HFRS – “Kazan Research Institute of Epidemiology and Microbiology of the Rospotrebnadzor”, based on official data provided by the Rospotrebnadzor institutions in the constituent entities of the Russian Federation. Statistical processing was conducted using conventional methods of variation statistics applying the Excel program. Over the past decades, hantavirus diseases have become very relevant and spread throughout the world. In the territory of the Russian Federation, natural foci of HFRS are located in the European part of the country, Western Siberia and Far East. The most epidemically active foci are situated in the European part of Russia. Over the past decade, the intensive incidence rate of HFRS in the Russian Federation stayed within the range of 3.0–9.5 per 100 thousand of the population, the long-term average annual indicator – 5.2 per 100 thousand of the population. In 2020, 3845 cases of HFRS were registered (2.62 per 100,000 of the population). There was a decrease in the incidence of HFRS by 3.6 times, compared with the indicators of 2019. A factor that may have influenced the decrease in the incidence of HFRS was the depression of the epizootic process among small mammals, the main carriers of HFRS pathogens, due to natural and climatic factors. The nature of the distribution of HFRS incidence across the territory of the Russian Federation in 2020 was heterogeneous. Statistical processing of the data made it possible to identify 5 groups of territories that differ in the level of HFRS incidence. Almost all constituent entities of the Volga Federal District and the Kostroma Region belonging to the Central Federal District were classified as groups of territories with high and very high incidence rates. In 2021, the deterioration of the epidemiological situation is predicted in the summer-autumn period of the year in the Volga Federal District and four entities of the Central Federal District