Magnetooptical Study of Zeeman Effect in Mn modulation-doped InAs/InGaAs/InAlAs Quantum Well Structures

We report on a magneto-photoluminescence (PL) study of Mn modulation-doped InAs/InGaAs/InAlAs quantum wells. Two PL lines corresponding to the radiative recombination of photoelectrons with free and bound-on-Mn holes have been observed. In the presence of a magnetic field applied in the Faraday geometry both lines split into two circularly polarized components. While temperature and magnetic field dependences of the splitting are well described by the Brillouin function, providing an evidence for exchange interaction with spin polarized manganese ions, the value of the splitting exceeds the expected value of the giant Zeeman splitting by two orders of magnitude for a given Mn density. Possible reasons of this striking observation are discussed

Hard X-ray Bursts from Collapse of the Super Massive Stars

The very first stars in the Universe can be very massive, up to $10^6M_\odot$. They would leave behind massive black holes that could act as seeds for growing super massive black holes of active galactic nuclei. Given the anticipated fast rotation such stars would end their live as super massive collapsars and drive powerful magnetically-dominated jets. In this paper we investigate the possibility of observing the bursts of high-energy emission similar to the Long Gamma Ray Bursts associated with normal collapsars. We show that during the collapse of supercollapsars, the Blandford-Znajek mechanism can produce jets as powerful as few$\times10^{51}$erg/s and release up to $10^{56}$erg of the black hole rotational energy. Due to the higher intrinsic time scale and higher redshift the initial bright phase of the burst can last for about $10^5$ seconds whereas the central engine would remain active for about 10 days. Due to the high redshift the burst spectrum is expected to be soft, with the spectral energy distribution peaking at around 60keV. The peak total flux density is relatively low, few$\times 10^{-7}erg\, cm^{-2} s^{-1}$, but not prohibitive. The such events should be rear 0.03 year$^{-1}$, the observations needs long term program and could be done in future.Comment: 4 pages, 2 figures. proceedings of workshop "Many faces of GRB phenomena - optics vs high energy", SAO Russia, October 12-16, 2009

The dynamics of interleukin-6level in HIV-infected patients with herpes zoster

Interleukin-6 plays a central role in antiviral immunity. However, the function of this cytokine in the pathogenesis of herpes zoster is unknown. The objective of this study was todeterminethe dynamicsof serum interleukin-6 level in HIV-infected patients with herpes zoster. 55 patients with herpes zoster (30 HIV-positive and 25 HIV-negative) were included. Serum interleukin-6 levels were measured before acyclovir treatment, on the 3rd day of treatment and after healing of skin lesions. The clinical course and dynamics of laboratory data were also evaluated. The study showed that elevated serum levels of interleukin-6 were associated with HIV-positive status, severity of rash, fever anddecreaseof CD4-lymphocytes. Levels of interleukin-6 in HIV-infected patients were significantly reduced during herpes zoster treatment and reached the level of HIVnegative cohort.Interleukin-6 levels in complicated course of herpes zoster in HIV-infected patients with low CD4-lymphocyte count (less than 350 cells/ml) were significantly higher compared to levels in uncomplicated course of the disease

Eight exoplanet candidates in SAO survey

Here we present eight new candidates for exoplanets detected by the transit method at the Special Astrophysical Observatory of the Russian Academy of Sciences. Photometric observations were performed with a 50-cm robotic telescope during the second half of 2020. We detected transits with depths of $\Delta m = 0.056-0.173^m$ and periods $P = 18.8^h-8.3^d$ in the light curves of stars with magnitudes of $m = 14.3-18.8^m$. All considered stars are classified as dwarfs with radii of $R_* = 0.4-0.6 R_{sun}$ (with the uncertainty for one star up to $1.1 R_{sun}$). We estimated the candidate radii (all are greater than 1.4 times the Jovian radius), semi-major axes of their orbits ($0.012-0.035 AU$), and other orbital parameters by modelling. We report the light curves with transits for two stars obtained in 2022 based on individual observations.Comment: 16 pages, 14 figures, 3 table

КРИПТОСПОРИДИОЗ У ВИЧ-ИНФИЦИРОВАННЫХ ПАЦИЕНТОВ: ДИАГНОСТИКА И КЛИНИКО-ЛАБОРАТОРНАЯ ХАРАКТЕРИСТИКА

The representatives of genus Cryptosporidium were found in 17 of 99 (17, 2%) HIV patients in Clinical Infectious Diseases Hospital named after S.P. Botkin. The restriction fragment length polymorphism (RFLP) assay identified two types of these agents Сriprtosporidium parvum in 11 (64,7%) and C. hominis in 6 (35,3%) patients. The level of CD4+ lymphocyte in the patients having cryptosporidiosis was significantly lower than in patients without cryptosporidiosis. In patients with cryptosporidiosis prolonged diarrhea were found at significantly higher rate. Also the patients with cryptosporidiosis demonstrated malnutrition and weight loss, but not at significantly higher rates. The present study is one of the first describe of cryptosporidiosis in Russia. риптоспоридии были обнаружены у 17 из 99 (17,2%) ВИЧ-инфицированных пациентов Клинической инфекционной больницы им. С.П. Боткина, Санкт-Петербург. С помощью полимеразной цепной реакции (ПЦР) и рестрикционного анализа методом полиморфизма длин рестрикционных фрагментов (ПДРФ) были выделены два вида возбудителей: Сriprtosporidium parvum у 11 (64,7%) и C. hominis – у 6 (35,3%) пациентов. У пациентов с криптоспоридиозом уровень CD4(+) лимфоцитов был достоверно ниже, чем у пациентов без криптоспоридиоза. У пациентов с криптоспоридиозом достоверно чаще наблюдались длительные (>10 дней) диареи. Нарушения всасывания питательных веществ и снижение массы тела выявлялись у пациентов с криптоспоридиозом, но достоверных отличий от пациентов без криптоспоридиоза по этим признакам выявлено не было. Данное исследование является одним из первых описаний криптоспоридийной инфекции у ВИЧ-положительных пациентов в России