92 research outputs found

    MASTER prompt and follow-up GRB observations

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    There are the results of gamma-ray bursts observations obtained using the MASTER robotic telescope in 2007 - 2009. We observed 20 error-boxes of gamma-ray bursts this period.The limits on their optical brightnesses have been derived. There are 5 prompt observations among them, obtained at our very wide field cameras. Also we present the results of the earliest observations of the optical emission of the gamma-ray bursts GRB 050824 and GRB 060926.Comment: 10 pages, 2 figure

    Master Robotic Net

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    The main goal of the MASTER-Net project is to produce a unique fast sky survey with all sky observed over a single night down to a limiting magnitude of 19 - 20mag. Such a survey will make it possible to address a number of fundamental problems: search for dark energy via the discovery and photometry of supernovas (including SNIa), search for exoplanets, microlensing effects, discovery of minor bodies in the Solar System and space-junk monitoring. All MASTER telescopes can be guided by alerts, and we plan to observe prompt optical emission from gamma-ray bursts synchronously in several filters and in several polarization planes.Comment: 10 pages, 8 figure

    Oxidative stress, a trigger of hepatitis C and B virus-induced liver carcinogenesis

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    Virally induced liver cancer usually evolves over long periods of time in the context of a strongly oxidative microenvironment, characterized by chronic liver inflammation and regeneration processes. They ultimately lead to oncogenic mutations in many cellular signaling cascades that drive cell growth and proliferation. Oxidative stress, induced by hepatitis viruses, therefore is one of the factors that drives the neoplastic transformation process in the liver. This review summarizes current knowledge on oxidative stress and oxidative stress responses induced by human hepatitis B and C viruses. It focuses on the molecular mechanisms by which these viruses activate cellular enzymes/systems that generate or scavenge reactive oxygen species (ROS) and control cellular redox homeostasis. The impact of an altered cellular redox homeostasis on the initiation and establishment of chronic viral infection, as well as on the course and outcome of liver fibrosis and hepatocarcinogenesis will be discussed The review neither discusses reactive nitrogen species, although their metabolism is interferes with that of ROS, nor antioxidants as potential therapeutic remedies against viral infections, both subjects meriting an independent review.publishersversionPeer reviewe

    Transient detections and other real-time data processing from wide-field chambers MASTER-VWF

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    At present time Robotic observatory making is of current importance. Having a large field of view and being able to point at anywhere, Robotic astronomical systems are indispensable when they looking for transients like grb, supernovae explosions, novae etc, as it's impossible in these cases to foresee what you should point you telescope at and when. In work are described prompt GRB observations received on wide-field chambers MASTER-VWF, and also methods of the images analysis and transients classifications applied in real-time data processing in this experiment. For 7 months of operation 6 synchronous observations of gamma-ray burst had been made by MASTER VWF in Kislovodsk and Irkutsk. In all cases a high upper limits have been received (see tabl \ref {tab_grbwf} and fig. \ref {allgrb}).Comment: 21 pages, 21 figure, 2 tables, Advances in Astronomy in pres

    Prokaryotic expression, purification and immunogenicity in rabbits of the small antigen of hepatitis delta virus

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    Funding Information: Expression and purification of HDV antigen was supported by Russian Foundation for Basic Research (grant 16-04-01490a). Evaluation of serum by Western blot and confocal microscopy was supported by Russian Science Foundation (grant 14-14-01021). Experiments in rabbits were supported by the Swedish Institute grants 09272_2013 and 19806_2016. Cross-border collaboration of the partners, exchange of the materials and standard operation procedures used in the study, and dissemination of the data were supported by the EU Twinning project VACTRAIN, contract nr 692293. Publisher Copyright: © 2016 by the authors; licensee MDPI, Basel, Switzerland.Hepatitis delta virus (HDV) is a viroid-like blood-borne human pathogen that accompanies hepatitis B virus infection in 5% patients. HDV has been studied for four decades; however, the knowledge on its life-cycle and pathogenesis is still sparse. The studies are hampered by the absence of the commercially-available HDV-specific antibodies. Here, we describe a set of reproducible methods for the expression in E. coli of His-tagged small antigen of HDV (S-HDAg), its purification, and production of polyclonal anti-S-HDAg antibodies in rabbits. S-HDAg was cloned into a commercial vector guiding expression of the recombinant proteins with the C-terminal His-tag. We optimized S-HDAg protein purification procedure circumventing a low affinity of the His-tagged S-HDAg to the Ni-nitrilotriacetyl agarose (Ni-NTA-agarose) resin. Optimization allowed us to obtain S-HDAg with >90% purity. S-HDAg was used to immunize Shinchilla grey rabbits which received 80 µg of S-HDAg in two subcutaneous primes in the complete, followed by four 40 µg boosts in incomplete Freunds adjuvant. Rabbits were bled two weeks post each boost. Antibody titers determined by indirect ELISA exceeded 107. Anti-S-HDAg antibodies detected the antigen on Western blots in the amounts of up-to 100 pg. They were also successfully used to characterize the expression of S-HDAg in the eukaryotic cells by immunofluorescent staining/confocal microscopy.publishersversionPeer reviewe

    Effect of aliskiren on post-discharge outcomes among diabetic and non-diabetic patients hospitalized for heart failure: insights from the ASTRONAUT trial

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    Aims The objective of the Aliskiren Trial on Acute Heart Failure Outcomes (ASTRONAUT) was to determine whether aliskiren, a direct renin inhibitor, would improve post-discharge outcomes in patients with hospitalization for heart failure (HHF) with reduced ejection fraction. Pre-specified subgroup analyses suggested potential heterogeneity in post-discharge outcomes with aliskiren in patients with and without baseline diabetes mellitus (DM). Methods and results ASTRONAUT included 953 patients without DM (aliskiren 489; placebo 464) and 662 patients with DM (aliskiren 319; placebo 343) (as reported by study investigators). Study endpoints included the first occurrence of cardiovascular death or HHF within 6 and 12 months, all-cause death within 6 and 12 months, and change from baseline in N-terminal pro-B-type natriuretic peptide (NT-proBNP) at 1, 6, and 12 months. Data regarding risk of hyperkalaemia, renal impairment, and hypotension, and changes in additional serum biomarkers were collected. The effect of aliskiren on cardiovascular death or HHF within 6 months (primary endpoint) did not significantly differ by baseline DM status (P = 0.08 for interaction), but reached statistical significance at 12 months (non-DM: HR: 0.80, 95% CI: 0.64-0.99; DM: HR: 1.16, 95% CI: 0.91-1.47; P = 0.03 for interaction). Risk of 12-month all-cause death with aliskiren significantly differed by the presence of baseline DM (non-DM: HR: 0.69, 95% CI: 0.50-0.94; DM: HR: 1.64, 95% CI: 1.15-2.33; P < 0.01 for interaction). Among non-diabetics, aliskiren significantly reduced NT-proBNP through 6 months and plasma troponin I and aldosterone through 12 months, as compared to placebo. Among diabetic patients, aliskiren reduced plasma troponin I and aldosterone relative to placebo through 1 month only. There was a trend towards differing risk of post-baseline potassium ≥6 mmol/L with aliskiren by underlying DM status (non-DM: HR: 1.17, 95% CI: 0.71-1.93; DM: HR: 2.39, 95% CI: 1.30-4.42; P = 0.07 for interaction). Conclusion This pre-specified subgroup analysis from the ASTRONAUT trial generates the hypothesis that the addition of aliskiren to standard HHF therapy in non-diabetic patients is generally well-tolerated and improves post-discharge outcomes and biomarker profiles. In contrast, diabetic patients receiving aliskiren appear to have worse post-discharge outcomes. Future prospective investigations are needed to confirm potential benefits of renin inhibition in a large cohort of HHF patients without D

    Inhibitive Protection of Low-Carbon Steel in Citric Acid Solutions

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    An effective mixture has been developed on the basis of the inhibitor IFKhAN-92 and KCNS to protect low-carbon steel in citric acid hot solutions. The proposed mixture inhibits the corrosion of steel in these solutions in a wide range of their concentrations (0.25÷2.0 М) and temperatures (20÷95°С). The effective inhibition of the corrosion of steel by the mixture under study is due to the strong retardation of the metal’s both electrode reaction
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