52 research outputs found
Dynamical chaos in the problem of magnetic jet collimation
We investigate dynamics of a jet collimated by magneto-torsional
oscillations. The problem is reduced to an ordinary differential equation
containing a singularity and depending on a parameter. We find a parameter
range for which this system has stable periodic solutions and study
bifurcations of these solutions. We use Poincar\'e sections to demonstrate
existence of domains of regular and chaotic motions. We investigate transition
from periodic to chaotic solutions through a sequence of period doublings.Comment: 11 pages, 29 figures, 1 table, MNRAS (published online
Gravitational radiospectrometer
Gravitational lensing is predicted by general relativity and is found in
observations. When a gravitating body is surrounded by a plasma, the lensing
angle depends on a frequency of the electromagnetic wave due to refraction
properties, and the dispersion properties of the light propagation in plasma.
The last effect leads to dependence, even in the uniform plasma, of the lensing
angle on the frequency, what resembles the properties of the refractive prism
spectrometer. The strongest action of this spectrometer is for the frequencies
slightly exceeding the plasma frequency, what corresponds to very long
radiowaves.Comment: 11 pages, 2 figure
Влияние гуминовых веществ угля и биокомпозиций с наночастицами серебра на их основе на баланс аргинина в перитонеальных макрофагах интактных мышей
Background. Antigen-presenting cells (APCs), especially macrophages, play an important role in the body defense against various pathogens. Their dysfunction and polarization are associated with most inflammatory and autoimmune diseases. The inflammatory process is regulated by activation and / or inhibition of genes differentially expressed by macrophages. Successful correction of inflammation leads firstly to elimination of inflammatory stimuli and then to remodeling and restoration of tissues and organs. It was experimentally confirmed that silvercontaining bionanocomposites based on natural humic substances (HS) obtained from coal of different origin, as well as initial matrices of these HS, are capable of activating pro- and anti-inflammatory properties of macrophages.Aim. To study cytotoxic, pyrogenic, and immunomodulatory properties (arginine balance) of initial HS samples and samples of silver nanoparticles ultradispersed in these HS matrices (HS-AgNPs) in the cell culture of peritoneal macrophages, as well as their effect on pro- and anti-inflammatory properties of APCs.Materials and methods. Cultural and biochemical methods were used in the study.Results. The study showed that the samples CHE-K, CHE-AgNPs, CHS-K, and CHP-K increased M1 macrophage polarization due to stimulation of the NO-synthase activity and inhibition of arginase. The samples CHI-K, CHIAgNPs, CHP-AgNPs, and CHS-AgNPs modulated an alternative M2 or M2-like state of macrophage activation. At the same time, HS are not cytotoxic at effective concentrations, and three out of four studied samples did not contain pyrogenic impurities.Conclusion. The use of HS and their silver-containing bionanocomposites, which have the ability to greatly affect the polarization of antigen-presenting cells, is a promising research area in correction of the inflammatory response for solving an important social and medical problem of treating chronic wounds. Введение. Антигенпрезентирующие клетки, особенно макрофаги, играют важную роль в защите организма от различных патогенов, их дисфункции, и поляризация связана с большинством воспалительных и аутоиммунных заболеваний. Воспалительный процесс жестко регулируется активацией и (или) ингибированием дифференциально экспрессируемых макрофагами генов. Успешная коррекция воспалительного процесса приводит к устранению воспалительных стимулов и далее ремоделированию и восстановлению тканей и органов. Экспериментально доказано, что биокомпозиции с наночастицами серебра на основе природных гуминовых веществ (ГВ) угля различного генеза, а также исходные матрицы данных ГВ способны активировать про- и противовоспалительные свойства макрофагов.Цель. Исследование в культуре клеток перитонеальных макрофагов цитотоксических, пирогенных и иммуномодулирующих свойств (баланс аргинина) исходных образцов ГВ и образцов наночастиц серебра, ультрадиспергированных в данных матрицах гуминовых веществ (ГВ-AgNPs),а также их влияния на про- и противовоспалительные свойства антигенпрезентирующих клеток. Материалы и методы. Использовались культуральные и биохимические методы.Результаты. Показано, что образцы CHE-K, CHE-AgNPs, CHS-K, CHP-K за счет усиления активности NOсинтазы и ингибиции аргиназы способствуют поляризации перитонеальных макрофагов по классическому типу (М1). Образцы CHI-K, CHI-AgNPs, CHP-AgNPs и CHS-AgNPs модулируют альтернативный М2 или M2-подобный тип (M2-like state) активации макрофагов. При этом ГВ не цитотоксичны в эффективных концентрациях, а также три из четырех исследуемых образцов не содержат пирогенных примесей.Заключение. Применение ГВ и серебросодержащих бионанокомпозиций на основе ГВ, обладающих способностью широко влиять на поляризацию антигенпрезентирующих клеток, является перспективным направлением исследований коррекции воспалительной реакции и, в частности, для решения острой социальной и медицинской проблемы – лечения хронических ран.
Modified carbon-containing electrodes in stripping voltammetry of metals. Part II. Composite and microelectrodes
Brachial artery status in patients with arterial hypertension and various variants of left ventricular remodeling
Aim. To assess middle-size vessel wall status, by volume compression oscillometry method, in patients with arterial hypertension (AH) and various variants of left ventricular (LV) remodeling. Material and methods. The study included 112 patients (44 males; mean age 53.5±11.1 years) with AH and reproducible LV myocardial mass index (LVMMI) >100 g/m2 at echocardiography. Brachial artery (BA) wall status was assessed by volume compressive oscillometry method. Results. LVMMI significantly correlated with levels of systolic and pulse blood pressure (BP) (r=0.28 and r=0.29, р<0.01). LV hypertrophy (LVH) was associated with minimal BA lumen diameter (BAD). Compared to eccentric LVH, concentric LVH was characterized by lower BAD and vascular wall deformation coefficient, as well as by increased linear blood flow velocity, volume elasticity module, total peripheral vascular resistance. Conclusion. LV remodeling variant could be linked to middle-size vessel viscosity and elasticity parameters
Innermost stable circular orbits of spinning test particles in Schwarzschild and Kerr space-times
Effective social help for elderly people: importance of long-term medical assistance at home
Due to the steady aging of the population the social situation to need for reforms has been identified, including a starting a state system of long-term medical care and monitoring at home for patients 65 years and over in Russia last years. The article includes the role, social significance and status for implementation of home medical patronage according the main tasks and priorities towards a decade of healthy ageing of WHO.The provision of home-based primary care in the framework of social protection for elderlies provides to use a typing system for organize targeted assistance for the seniors and persons with disabilities in Russia. By analogy, typing of patients is envisaged and is being developed for conducting medical home nursing.The typing model for long-term medical support of old patients has their own characteristics, from the risk factors and the “philosophical approach” through the end of the multidisciplinary medical team formation and the need for vaccination.</jats:p
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