Stochastic structures in the low-frequency plasma turbulence: measurement of characteristics and determination of general features

Results are presented from the experimental and statistical studies of low-frequency turbulence in a magnetized plasma. It is shown that, for all types of driving instability (drift, ion-acoustic, MHD instability), this turbulence is accompanied by the formation of stochastic structures demonstrating a statistically consistent behavior and similar correlation, spectral, probability characteristics. The stochastic structures that are existing in the state of dynamic equilibrium and non-random interaction determine all common features of very different turbulent processes: ionacoustic nonlinear solitons, drift vortices, and MHD spatial structures. It follows that the structural turbulence is a non-Gaussian probability process with the long memory, i.e., a self-similar probability process

Features of the course of hemorrhagic fever with renal syndrome in HIV-infected patients

Human immunodeficiency virus (HIV) is a significant medical and social problem for many developed countries. HIV infection is featured with developing chronic kidney pathology as well as acute renal damage. In some regions, hemorrhagic fever with renal syndrome (HFRS) can contribute somehow to developing renal pathology in HIVinfected subjects. The aim of the study was to identify clinical and laboratory features of HFRS course during HIV infection. A retrospective study was conducted by forming two groups: group 1 consisted of 9 patients suffered from HFRS together with verified HIV infection, group 2 — 53 patients with HFRS but lacking any clinical and epidemiological indications supporting HIV infection. Subjects in both groups were age- and sex-matched. The average age of the patients in group 1 and group 2 was 34 and 31 years, respectively. For statistical analysis, the licensed SPSS 22.0 software was used. A significance level p for statistical criteria was set equal to 0.05. In general, HFRS course in all patients was accompanied by characteristic signs: intoxication syndrome, impaired vision, hemorrhagic rash, pain in the lumbar region, decreased diuresis, thrombocytopenia, proteinuria, polymorphic urinary syndrome and azotemia. HFRS patients with concomitant HIV infection often complain of dry mouth, bloating, visible shortness of breath. Laboratory changes describe more severe kidney damage. A direct strong correlation was shown between leukocyte count and level of blood urea in patients with concomitant HIV infection (r = 0.798; p = 0.01). The combination of HFRS and HIV was accompanied by a milder HFRS course — rate of mild disease was almost 6-fold higher among patients of this group. In this case, no cases of severe hemorrhagic fever with renal syndrome combined with HIV were noted. Our study allowed to obtain unambiguous data. Predisposition of HIV-infected patients to renal pathology may be a determining factor in kidney damage upon emerging HFRS: more prominent rise in creatinine and urea level. Moreover, according to rating scale for assessing HFRS severity, it formally turned out that during concomitant HIV infection patients more often fit to a mild disease severity, even in the presence of more pronounced renal manifestations. The occurrence of acute renal pathology in HIV-infected patients is a life-threatening condition, a factor of deterioration of chronic renal pathology and a predictor of death. Consequently, this patient population requires thorough monitoring both at inpatient and outpatient stages

Сardiac arrhythmias in people who have had a coronavirus infection COVID-19: A review

Heart rhythm disorders are one of the most common complications of coronavirus infection. Heart rhythm disorders can develop in 6–17% of hospitalized patients, and in convalescents, COVID-19 can manifest itself up to 12 months after the completion of the acute phase of the disease. Among the mechanisms for the development of cardiac arrhythmias, there are a direct cytopathic effect of SARS-CoV-2 on the myocardium, systemic inflammatory response syndrome, electrolyte imbalance, hypoxia, the use of antibacterial, antimalarial and antiviral drugs, exudative pericarditis, autonomic dysfunction. The main COVID-19-mediated heart rhythm disorders are sinus tachycardia and bradycardia, atrial fibrillation, ventricular tachycardia, long QT syndrome. Despite a significant amount of research, the literature data on the prevalence of certain types of cardiac arrhythmias (especially in COVID-19 convalescents), as well as methods for their correction, are somewhat contradictory and need to be clarified. Taking into account the impact of arrhythmia on the quality of life and mortality, active monitoring of convalescents of coronavirus infection, identification and development of approaches to the treatment of heart rhythm disorders in patients who have had COVID-19, seem to be relevant and promising areas in modern cardiology

A new Borrelia on the block: Borrelia miyamotoi – a human health risk?

Background Borrelia miyamotoi clusters phylogenetically among relapsing fever borreliae, but is transmitted by hard ticks. Recent recognition as a human pathogen has intensified research into its ecology and pathogenic potential. Aims We aimed to provide a timely critical integrative evaluation of our knowledge on B. miyamotoi, to assess its public health relevance and guide future research. Methods This narrative review used peer-reviewed literature in English from January 1994 to December 2018. Results Borrelia miyamotoi occurs in the world’s northern hemisphere where it co-circulates with B. burgdorferi sensu lato, which causes Lyme disease. The two borreliae have overlapping vertebrate and tick hosts. While ticks serve as vectors for both species, they are also reservoirs for B. miyamotoi. Three B. miyamotoi genotypes are described, but further diversity is being recognised. The lack of sufficient cultivable isolates and vertebrate models compromise investigation of human infection and its consequences. Our understanding mainly originates from limited case series. In these, human infections mostly present as influenza-like illness, with relapsing fever in sporadic cases and neurological disease reported in immunocompromised patients. Unspecific clinical presentation, also occasionally resulting from Lyme- or other co-infections, complicates diagnosis, likely contributing to under-reporting. Diagnostics mainly employ PCR and serology. Borrelia miyamotoi infections are treated with antimicrobials according to regimes used for Lyme disease. Conclusions With co-infection of tick-borne pathogens being commonplace, diagnostic improvements remain important. Developing in vivo models might allow more insight into human pathogenesis. Continued ecological and human case studies are key to better epidemiological understanding, guiding intervention strategies

Stimulated Cherenkov Radiation of Plasma Waves and Plasma Turbulence

No abstract availabl

Absorption of Microwaves in Different Regimes of Electron Cyclotron Plasma Heating at the L-2M Stellarator

Abstract: The results are presented from studies of the extraordinary wave (X-wave) absorption in plasma of the L-2M stellarator, as well as the power loss of microwave beam introduced into the plasma. The X-wave occurs as a result of splitting the linearly polarized gyrotron radiation, as it intersects the plasma boundary. Different electron cyclotron resonance heating (ECRH) regimes were studied: heating by a sequence of microwave pulses and heating that involves an auxiliary ECRH pulse. It was ascertained that for the X-wave, the single-pass absorption coefficient along the central chord of the plasma cross section is higher than 95%, and in the axial ECRH regime, the power losses correspond to the O-wave power. It was ascertained that the power loss of the beam inputted into the plasma increases up to 20–23% when the gyroresonance region was displaced towards the inner wall of the vacuum chamber and the ECRH pulse duration was increased. At the same time, the radiation loss drastically increased. It was hypothesized that an increase in the power loss is caused by a decrease in the X-wave absorption coefficient integrated over the beam cross section, which occurs due to a decrease in the electron temperature across the microwave beam cross section. In the regime with the auxiliary ECRH pulse, the pulsed sputtering of the vacuum chamber coating occurs, and the electron density and temperature change; nevertheless, the absorption coefficient along the central chord exceeds 90%. © 2021, Pleiades Publishing, Ltd