Two peaks of total current in streamer propagation

The numerical simulations of the cathode directed streamer propagation in the discharge gap, with the streamer going out to cathode, are carried out. The processes are found, which take place near anode and contribute to the formation of the first of two maxima of total current time dependence. The factors are considered, which determine the propagation of the ionization process at the final stage, when the streamer approaches the cathode, and the ionization wave is propagating along the cathode surface.Виконане числове моделювання поширення спрямованого до катода стримера у розрядному проміжку з виходом стримера на катод. Знайдені процеси, які відбуваються поблизу анода та сприяють формуванню першого з двох максимумів у залежності повного струму від часу. Розглянуті чинники, які визначають поширення процесу іонізації на завершальній стадії, при наближенні стримера до катода та поширенні хвилі іонізації уздовж поверхні катода.Выполнено численное моделирование распространения направленного к катоду стримера в разрядном промежутке с выходом стримера на катод. Найдены процессы, происходящие вблизи анода и способствующие формированию первого из двух максимумов в зависимости полного тока от времени. Рассмотрены факторы, определяющие распространение процесса ионизации на завершающей стадии, при приближении стримера к катоду и распространении волны ионизации вдоль поверхности катода

Azimuthal stability of trichel pulses and cathode directed streamers

The numerical simulations of negative corona discharge in Trichel pulse mode are carried out with the calculation of evolution of azimuthal perturbations. It is found the azimuthal instability with increment corresponding to avalanche development. This instability is suppressed at the nonlinear stage and does not lead to the process branching. The result is also applicable to the azimuthal instability of the cathode directed streamer, found earlier. The difference in their increments is followed from the difference in courses of the processess, which is discussed.Виконане числове моделювання негативної корони в режимі імпульсів Тричела з розрахунком еволюції азимутальних збурень. Виявлено азимутальну нестійкість з інкрементом, відповідним розвитку лавини. Ця нестійкість пригнічується на нелінійній стадії і не веде до галуження процесу. Результат також застосовується до виявленої раніше азимутальної нестійкості спрямованого до катода стримера. Різниця в їхніх інкрементах випливає з різниці в ході процесів, які обговорюються.Выполнено численное моделирование отрицательной короны в режиме импульсов Тричела с расчетом эволюции азимутальных возмущений. Выявлена азимутальная неустойчивость с инкрементом, соответствующим развитию лавины. Эта неустойчивость подавляется на нелинейной стадии и не ведет к ветвлению процесса. Результат также применим к выявленной ранее азимутальной неустойчивости направленного к катоду стримера. Разница в их инкрементах следует из разницы в ходе процессов, которые обсуждаются

Numerical simulations of cathode directed streamer propagation in electronegative gases

The numerical simulations are carried out for the cathode directed streamer propagation at the quasi-stationary stage, far from electrodes, and at the stage of going out to cathode, in the gases with the different combinations of three-body and dissociative attachment. The typical features of the process in presence of intensive attachment are revealed.Виконано числове моделювання поширення катодоспрямованого стримера на квазістаціонарній стадії, далеко від електродів, та на стадії виходу на катод у газах з різним поєднанням трьохтільного та дисоціативного приставання. Виявлено типові риси процесу за наявності інтенсивного приставання.Выполнено численное моделирование распространения катодонаправленного стримера на квазистационарной стадии, вдали от электродов и на стадии выхода на катод в газах с разным сочетанием трехтельного и диссоциативного прилипания. Выявлены типичные черты процесса при наличии интенсивного прилипания

Secondary streamers in the primary streamer channel

The propagation of the process with ionization and attachment in the remainder of the streamer channel is studied. From the simplified model consideration it is shown that in the conditions of the attachment instability development the spatially inhomogeneous perturbations move to anode. The conditions, in which the perturbations move to cathode, as it is usually observed for the secondary streamers, are discussed.Вивчається поширення процесу з іонізацією та налипанням у залишку каналу стримера. З розгляду спрощеної моделі видно, що в умовах розвитку налипальної нестійкості просторово неоднорідні збурення рухаються до анода. Обговорюються умови, за яких ті збурення рухаються до катода, як це зазвичай спостерігається для вторинних стримерів.Изучается распространение процесса с ионизацией и прилипанием в остатке канала стримера. Из рассмотрения упрощенной модели видно, что в условиях развития прилипательной неустойчивости пространственно неоднородные возмущения движутся к аноду. Обсуждаются условия, при которых эти возмущения движутся к катоду, как это обычно наблюдается для вторичных стримеров

Flux-splitting schemes for parabolic problems

To solve numerically boundary value problems for parabolic equations with mixed derivatives, the construction of difference schemes with prescribed quality faces essential difficulties. In parabolic problems, some possibilities are associated with the transition to a new formulation of the problem, where the fluxes (derivatives with respect to a spatial direction) are treated as unknown quantities. In this case, the original problem is rewritten in the form of a boundary value problem for the system of equations in the fluxes. This work deals with studying schemes with weights for parabolic equations written in the flux coordinates. Unconditionally stable flux locally one-dimensional schemes of the first and second order of approximation in time are constructed for parabolic equations without mixed derivatives. A peculiarity of the system of equations written in flux variables for equations with mixed derivatives is that there do exist coupled terms with time derivatives

A relevant in vitro rat model for the evaluation of blood-brain barrier translocation of nanoparticles

Poly(MePEG2000cyanoacrylate-co-hexadecylcyanoacrylate) (PEG-PHDCA) nanoparticles have demonstrated their capacity to reach the rat central nervous system after intravenous injection. For insight into the transport of colloidal systems across the blood-brain barrier (BBB), we developed a relevant in vitro rat BBB model consisting of a coculture of rat brain endothelial cells (RBECs) and rat astrocytes. The RBECs used in our model displayed and retained structural characteristics of brain endothelial cells, such as expression of P-glycoprotein, occludin and ZO-1, and immunofluorescence studies showed the specific localization of occludin and ZO1. The high values of transendothelial electrical resistance and low permeability coefficients of marker molecules demonstrated the functionality of this model. The comparative passage of polyhexadecylcyanoacrylate and PEG-PHDCA nanoparticles through this model was investigated, showing a higher passage of PEGylated nanoparticles, presumably by endocytosis. This result was confirmed by confocal microscopy. Thanks to a good in vitro/in vivo correlation, this rat BBB model will help in understanding the mechanisms of nanoparticle translocation and in designing new types of colloidal carriers as brain delivery systems

The Influence of International Law on the International Movement of Persons

Many migration theories identify ‘the law’ as a significant constraint on the international movement of persons. While this constraint often operates through national migration legislation, this study examines the influence of international law in shaping contemporary patterns in the international movement of persons at the macro level. The analysis begins with an examination of the long-established power of a State to regulate cross-border movement of persons as an inherent attribute of State sovereignty, together with the accepted limitations on a State’s power to control entry and exit. Yet, international law reaches well beyond the movement of people across borders. The development of international human rights law has been a key constraint on state action in the United Nations era by also regulating the treatment of migrants within a State’s borders. The study considers how international law has responded to current migration issues, including: protection of migrant women and children; suppression of smuggling and trafficking of people; labour migration; and environmental migration. As in other areas of international society, there has been a proliferation of institutions through which international migration law is made and enforced. The most prominent among them are the United Nations High Commissioner for Refugees (UNHCR) and the International Organization for Migration (IOM), but the establishment of other entities with overlapping mandates has given rise to calls for a new international migration regime based on streamlined institutional arrangements. The study concludes that international law is an imperfect framework for regulating the international movement of persons because it has developed in a piecemeal fashion over a long time to deal with issues of concern at particular points in human history. Yet, despite its shortfalls, international law and its associated institutions unquestionably play a most important role in constraining and channeling state authority over the international movement of persons

Relevant Issues of Epidemiological Safety Provision as Regards Natural-Focal Infections during the XXII Olympic and XI Paralympic Winter Games in Sochi

The paper contains the data on the morbidity rates as regards natural-focal infectious diseases and results of epizootiological monitoring in the locality of the XXII Olympic and XI Paralympic Winter Games-2014 in Sochi. It is demonstrated that the significant ones in the infectious disease incidence chart are hemorrhagic fever with renal syndrome, Ixodidae tick-borne borrelioses, pseudotuberculosis, intestinal yersiniosis, leptospiroses, rabies, rickettsiosis, and tularemia. Represented are the data on the peculiarities of a number of regional pathogenic strains. Noted is fact that complex activities, which were carried out by the agencies and institutions of the Rospotrebnadzor, Krasnodar Territory and Sochi resort-town Administration, allowed for the stabilization of the situation on natural-focal infections

Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease

Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.