QZ Serpentis: A Dwarf Nova with a 2-Hour Orbital Period and an Anomalously Hot, Bright Secondary Star

We present spectroscopy and time-series photometry of the dwarf nova QZ Ser. The spectrum shows a rich absorption line spectrum of type K4 +- 2. K-type secondary stars are generally seen in dwarf novae with orbital periods P-orb around 6 h, but in QZ Ser the absorption radial velocities show an obvious modulation (semi-amplitude 207(5) km/s) at P-orb = 119.752(2) min, much shorter than typical for such a relatively warm and prominent secondary spectrum. The H-alpha emission-line velocity is modulated at the same period and roughly opposite phase. Time-series photometry shows flickering superposed on a modulation with two humps per orbit, consistent with ellipsoidal variation of the secondary's light. QZ Ser is a second example of a relatively short-period dwarf nova with a surprisingly warm secondary. Model calculations suggest that the secondary is strongly enhanced in helium, and had already undergone significant nuclear evolution when mass transfer began. Several sodium absorption features in the secondary spectrum are unusually strong, which may indicate that the present-day surface was the site of CNO-cycle hydrogen burning in the past.Comment: 11 pages, 3 postscript figures, 1 jpeg greyscale figure. Accepted for publication in PAS

Identification of new cataclysmic variables in the 1RXS and USNO-B1.0 catalogs

As a result of applying the original optical variability search method on publicly available data, we have found eight new cataclysmic variables and two possible Optically Violent Variable quasars among the previously unidentified X-ray sources in the ROSAT catalog. We describe the search method and present the characteristics of the newly identified variable stars. The obtained results demonstrate the large potential of the concept of Virtual Observatory for identifying new objects of astrophysical interest.Comment: 16 pages, 11 figures, 2 tables; submitted to Astronomy Letter

The formation of oxidative disorders in the population of Vladivostok under the influence of atmospheric microparticles

We studied the response of trigger systems in healthy volunteers living in areas with different levels of air pollution. We determined that particles with the size of 800 microns and higher of relatively favorable region, particles with the size of less than 50 microns dominated in the air of the unfavorable area, among which there were the most hazardous to health amounts of microparticles - from 200 to 300 nm. Microparticles of unfavorable area causes the development of oxidative modifications of proteins and DNA contributing to the change of leukocyte potential energy. The increase in total antioxidant activity and response of thiol-disulfide system (the increase in thioredoxin, glutathione with a stable reductase level] maintains a balance of oxidation and antioxidant processes contributing to protection of the cellular and subcellular structures against considerable oxidative damage

Second Cluster Integral and Excluded Volume Effects for the Pion Gas

The quantum mechanical formula for Mayer's second cluster integral for the gas of relativistic particles with hard-core interaction is derived. The proper pion volume calculated with quantum mechanical formula is found to be an order of magnitude larger than its classical evaluation. The second cluster integral for the pion gas is calculated in quantum mechanical approach with account for both attractive and hard-core repulsive interactions. It is shown that, in the second cluster approximation, the repulsive pion-pion-interactions as well as the finite width of resonances give important but almost canceling contributions. In contrast, an appreciable deviation from the ideal gas of pions and pion resonances is observed beyond the second cluster approximation in the framework of the Van der Waals excluded-volume model.Comment: 29 pages, Latex, 9 PS-figure

Polyunsaturated fatty acid status of leukocyte membranes in COPD patients

The aim of the study was to analyze n-3 and n-6 polyunsaturated fatty acid (PUFA) profile of blood leukocyte cytomembranes in mild and moderate COPD, and to establish possible role of these fatty acids in COPD progression. The study involved 110 patients with mild disease (n = 60) and moderate COPD (50 patients), at average age of 57.5±4.8 years old. The control group consisted of 32 practically healthy non-smoking people with normal pulmonary function (average age 42.0±3.4 years). The immunological study included flow cytometric determination of blood immune cell subpopulations, i.e., T lymphocytes (CD3+), T helper cells (CD4+), cytotoxic T lymphocytes (CD8+), and B cells (CD19+) using Becton Dickinson machine (USA). Fatty acid methyl esters redissolved in hexane were analyzed using “Shimadzu GC-2010” gas-liquid chromato-graphic system (Japan). Analysis of the polyunsaturated fatty acid profile of leukocyte membranes in COPD patients revealed a reduced concentration of essential linoleic acid (18:2n-6) regardless of the disease severity. The leukocyte membrane levels of the long-chain n-6 PUFAs, such as dihomo-γ-linolenic acid (20:3n-6), arachidonic acid (20:4n-6), and docosatetraenoic acid (22:4n-6), were elevated in patients with COPD compared with the control group. However, the concentration of the described above n-6 PUFAs in leukocyte membranes was increased in patients with moderate COPD compared to the patients with mild COPD. The significant deficiency of a physiologically important n-3 PUFA, eicosapentaenoic acid (20:5n- 3), in leukocyte membranes in the COPD patients was revealed. In turn, the low level of 20:5n-3 could result from the deficiency of its precursor, docosahexaenoic acid (22:6n-3). The results of the study indicate the modification in the PUFA composition of blood leukocyte membranes in the patients with COPD. It was shown that altered composition of long-chain fatty acid of leukocyte membranes emerges already at the early stage of the disease. Therefore, the imbalance in fatty acids composition of leukocytes makes a significant contribution to the development and the progression of COPD

Optical polarization observations with the MASTER robotic net

We present results of optical polarization observations performed with the MASTER robotic net for three types of objects: gamma-ray bursts, supernovae, and blazars. For the Swift gamma-ray bursts GRB100906A, GRB110422A, GRB121011A, polarization observations were obtained during very early stages of optical emission. For GRB100906A it was the first prompt optical polarization observation in the world. Photometry in polarizers is presented for Type Ia Supernova 2012bh during 20 days, starting on March 27, 2012. We find that the linear polarization of SN 2012bh at the early stage of the envelope expansion was less than 3%. Polarization measurements for the blazars OC 457, 3C 454.3, QSO B1215+303, 87GB 165943.2+395846 at single nights are presented. We infer the degree of the linear polarization and polarization angle. The blazars OC 457 and 3C 454.3 were observed during their periods of activity. The results show that MASTER is able to measure substantially polarized light; at the same time it is not suitable for determining weak polarization (less than 5%) of dim objects (fainter than 16$^m$). Polarimetric observations of the optical emission from gamma-ray bursts and supernovae are necessary to investigate the nature of these transient objects.Comment: 31 pages, 12 figures, 4 tables; Exposure times in Table 2 have been correcte

Nerve growth factor and post-infarction cardiac remodeling

The prevalence of sudden death from chronic heart failure and cardiac arrhythmias caused by myocardial infarction is a complex problem in cardiology. Post-infarction cardiac remodeling occurs after myocardial infarction. This compensatory-adaptive reaction, regulated by mechanical, neurohumoral and genetic factors, includes the structural and functional changes of cardiomyocytes, stromal elements and extracellular matrix, geometry and architectonics of the left ventricular cavity. Adverse left ventricular remodeling is associated with heart failure and increased mortality. The concept of post-infarction cardiac remodeling is an urgent problem, since the mechanisms of development and progression of adverse post-infarction changes in the myocardium are completely unexplored. In recent years, the scientist attention has been focused on neurotrophic factors involved in the sympathetic nervous system and the vascular system remodeling after myocardial infarction. Nerve growth factor (NGF) is a protein from the neurotrophin family that is essential for the survival and development of sympathetic and sensory neurons, which also plays an important role in vasculogenesis. Acute myocardial infarction and heart failure are characterized by changes in the expression and activity of neurotrophic factors and their receptors, affecting the innervation of the heart muscle, as well as having a direct effect on cardiomyocytes, endothelial and smooth muscle vascular cells. The identification of the molecular mechanisms involved in the interactions between cardiomyocytes and neurons, as well as the study of the effects of NGF in the cardiovascular system, will improve understanding of the cardiac remodeling mechanism. This review summarizes the available scientific information (2019–2021) about mechanisms of the link between post-infarction cardiac remodeling and NGF functions