Use of Nanocomposite Material Based on Graphene Oxide and Silver Nanoparticles in Research of Blood Erythrocytes in Various Diseases

The electrical and structural properties of a nanocomposite material based on silver nanoparticles and graphene oxide were investigated. Using electron and atomic force microscopy it was shown that the nanoparticles formed predominantly have sizes from 60 to 100 nm. Measurements of the current-voltage characteristics showed electrical conductivity values significantly exceeding the parameters of the initial graphene oxide. The prepared nanocomposites were used for scanning by electron microscopy (SEM) of blood samples of sick children with hematuria syndrome and patients of the radiological department of an oncologic dispensary diagnosed with cervical cancer. The formation of nanosize objects on the surface of erythrocytes is revealed. The size of these volumes is comparable to the size of the viruses. Results of these studies can indirectly confirm an assumption of authors about possible transportation of viruses by erythrocytes to various organs and viral etiology of renal diseases with the hematuria syndrome and cervical cancer. Keywords: graphene, graphene oxide, silver nanoparticles, structural and electrical properties, nephropathy, diagnostics

Cyclic brightening in the short-period WZ Sge-type cataclysmic variable SDSS J080434.20+510349.2

We have observed a new cataclysmic variable (CV) SDSS J080434.20+510349.2 and study the origin of a long-term variability found in its light curve. Multi-longitude time-resolved photometric observations were carried out to analyze the uncommon behavior also found recently in two newly discovered CVs. This study of SDSS J080434.20+510349.2 mainly concerns the understanding of the nature of the observed double-humped light curve and its relation to a cyclic brightening occurring during quiescence. The observations were obtained early in 2007, when the object was at about V~17.1, 0.4 mag brighter than the pre-outburst magnitude. The light curve shows a sinusoidal variability with an amplitude of about 0.07 mag and a periodicity of 42.48 min, which is half of the orbital period of the system. In addition, we have observed two "mini-outbursts" of the system up to 0.6 mag, with a duration of about 4 days each. The "mini-outburst" had a symmetric profile and repeated in about 32 days. Subsequent monitoring of the system shows a cyclical behaviour of such "mini-outbursts" with a similar recurrence period. The origin of the double-humped light curve and the periodic brightening is discussed in the light of the evolutionary state of SDSS J080434.20+510349.2.Comment: 7 pages, 6 figures, Accepted by A&A, typos added, figure correcte

Investigation of the new cataclysmic variable 1RXS J180834.7+101041

We present the results of our photometric and spectroscopic studies of the new eclipsing cataclysmic variable star 1RXS J180834.7+101041. Its spectrum exhibits double-peaked hydrogen and helium emission lines. The Doppler maps constructed from hydrogen lines show a nonuniform distribution of emission in the disk similar to that observed in IP Peg. This suggests that the object can be a cataclysmic variable with tidal density waves in the disk. We have determined the component masses (M_WD =0.8 \pm 0.22 M_sun and M_RD =0.14 \pm 0.02 M_sun) and the binary inclination (i =78 \pm 1.5 deg) based on well-known relations between parameters for cataclysmic variable stars. We have modeled the binary light curves and showed that the model of a disk with two spots is capable of explaining the main observed features of the light curves.Comment: 22 pages, 9 figures, 2 tables, published in Astronomy Letters, 2011, 37, 845-85

COMPLEX APPROACH IN TREATMENT OF ESOPHAGEAL CANCER

The article proves choice of the method of treatment of patients with esophageal cancer. The authors suppose that combined treatment of esophageal cancer with, preoperative and postoperative radio- and chemotherapy allows to improve remote results of surgical treatment

The disappearance and reappearance of optical emission lines and the drop in a Swift/XRT count rate during the recent rebrightening of TCP J21040470+4631129

We report the results of our continuing optical and X-ray monitoring of the bright WZ Sge-type dwarf nova TCP J21040470+4631129 (hereafter TCP2104) discovered on July 12, 2019 (for previous reports, see ATel #12947, #13009). Our optical photometric observations are mostly performed using 30-cm class telescopes, while spectroscopic data are obtained with the 2.1-m telescope at the OAN-SPM, the 2.5-m Isaac Newton Telescope on La Palma, and other smaller telescopes.peer-reviewe

Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency

A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20 MHz. The measured values of the dead-time range from 70 ns to 100 ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40 MHz and at higher luminosity