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AbstractThe present communication evaluates the antigen B (AgB) family of bubaline isolates of Echinococcus granulosuswith respect to their conformational propensity and also discusses the stretches of agretope. AgB, which is abundantly present in hydatid cyst fluid, is encoded by a gene family, AgB1?AgB5. Hydatidosis is of zoonotic and economic importance in India. Buffaloes serve as the intermediate host. However, to date the AgB family has not been fully analysed. During the present study two different primers used for amplification of AgB1revealed homology to Echinococcus canadensis(G8) as well as E. granulosus sensu stricto(G1/G2). The sequence of AgB3 is homologous to that of the well-defined species, Echinococcus ortleppi(G5), and the predicted amino acid sequence of AgB4 is homologous to bovine isolates identified earlier. ?- and ?-amphipathic structures were recorded in all the antigens designated as T-cell receptor sites. The antigenic index of different stretches correlated with hydrophilicity because the hydrophobic residues are not accessible to the cells. In this study, we investigated the binding propensity of AgB to MHC II in order to determine stretches of agretope. Agretopes began with four hydrophilic residues. Two to three additional hydrophilic residues were present in the internal motif. This comparison of AgB and its family of bubaline isolates, with respect to their sequence information, ?- and ?- amphipathic regions, antigenic index and stretches of agretope is the first such report from India. [ABSTRACT FROM AUTHOR]

AbstractIn the present study viable protoscoleces of Echinococcus granulosuswere exposed to in vitroanthelmintic treatment to observe efficacy against Indian buffalo isolates. Evaluation criteria included morphological changes, viability scores and expression of peptides as a product of prestressed protoscoleces. Protoscolex changes included presence of bladder-like structure and morphological distortion. Two peptides of relative molecular weight (Mr) 40 and 70?kDa were visualized when proteins were separated by discontinuous gel electrophoresis. These two peptides seemed to be products of prestressed protoscoleces. [ABSTRACT FROM AUTHOR]

Composite thin films of (SrBi2Ta2O9)(1[?]x)-(La0.67Sr0.33MnO3)x are prepared for the first time using the pulsed-laser deposition technique with ablation occurring from two individual targets. X-ray diffraction and field-emission scanning electron microscopy reveal the formation of ferromagnetic La0.67Sr0.33MnO3 embedded in the ferroelectric SrBi2Ta2O9 phase. Complex impedance spectroscopy is carried out on the composite at different temperatures. Bulk resistance calculated from the complex impedance plot decreases with the increase in temperature up to 80 degC, an observation contradicting earlier results. However, the increase in resistivity of the La0.67Sr0.33MnO3 phase with temperature as the metal-to-insulator transition temperature (80 degC) is approached explains the observation. Also, the resistivity decreases with the increase in La0.67Sr0.33MnO3 content at a particular temperature. Electric modulus, dielectric spectroscopy and ac conductivity are used to study the transport property of the films. Activation energy, from the Arrhenius plot, is studied to discuss the conduction mechanism in the composite thin films. [ABSTRACT FROM AUTHOR]

We present multi-wavelength follow-up campaigns by the AstroSat CZTI and GROWTH collaborations in search of an electromagnetic counterpart to the gravitational wave event GW 170104. At the time of the GW 170104 trigger, the AstroSat CZTI field of view covered 50.3% of the sky localization. We do not detect any hard X-ray (>100 keV) signal at this time, and place an upper limit of , for a 1 s timescale. Separately, the ATLAS survey reported a rapidly fading optical source dubbed ATLAS17aeu in the error circle of GW 170104. Our panchromatic investigation of ATLAS17aeu shows that it is the afterglow of an unrelated long, soft GRB 170105A, with only a fortuitous spatial coincidence with GW 170104. We then discuss the properties of this transient in the context of standard long GRB afterglow models. [ABSTRACT FROM AUTHOR]

Ferroelectric SrBi2Ta2O9 (SBT) thin films have been deposited by the radio-frequency magnetron sputtering technique on bare p-Si as well as on HfO2 insulating buffer p-Si. XRD patterns revealed the formation of a well-crystallized SBT perovskite thin film on the HfO2 buffer layer. The electrical properties of the metal-ferroelectric-insulator-semiconductor (MFIS) structure were characterized by varying thicknesses of the HfO2 layer. The MFIS structure exhibits a maximum clockwise C-V memory window of 1.60 V when the thickness of the HfO2 layer was 12 nm with a lower leakage current density of 6.20 × 10[?]7 A cm[?]2 at a positive applied voltage of 7 V. However, the memory window reaches a maximum value of 0.7 V at a bias voltage of ±5 and then decreases due to charge injection in the case of the insulating buffer layer thickness of 3 nm. The density of oxide trapped charges at/near the buffer layer-ferroelectric interface is studied by the voltage stress method. Capacitance-voltage (C-V) and leakage current density (J-V) characteristics of the Al/SBT/HfO2/Si(1 0 0) capacitor indicate that the introduction of the HfO2 buffer layer prevents interfacial diffusion between the SBT thin film and the Si substrate effectively and improves the interface quality. Furthermore, the Al/SBT/HfO2/Si structures exhibit excellent retention characteristics, the high and low capacitance values clearly distinguishable for over 1 h and 30 min. This shows that the proposed Al/SrBi2Ta2O9/HfO2/Si structure is ideally suitable for high performance ferroelectric memories. [ABSTRACT FROM AUTHOR]

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a 3-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescopes and the Giant Metrewave Radio Telescope. Our observations, combined with observations at other wavelengths, have allowed us to determine the GRB blast wave physical parameters, such as the total burst energy and the ambient medium density, as well as to investigate the jet nature of the relativistic outflow. Further, by modelling the late-time radio light curve of GRB 030329, we predict that the Low-Frequency Array (30–240MHz) will be able to observe afterglows of similar GRBs, and constrain the physics of the blast wave during its non-relativistic phase. [ABSTRACT FROM AUTHOR]

The Be/X-ray binary 4U 0115+63 was observed by the Large Area X-ray Proportional Counter (LAXPC) instrument on AstroSat on 2015 October 24 during the peak of a giant Type II outburst. Prominent intensity oscillations at ∼1 and ∼2 mHz frequency were detected during the outburst. Nuclear Spectroscopic Telescope Array (NuSTAR) observations made during the same outburst also show millihertz quasi-periodic oscillations (QPOs). Details of the oscillations and their characteristics deduced from LAXPC/AstroSat and NuSTAR observations are reported in this paper. Analysis of the archival Rossi X-ray Timing Explorer/Proportional Counter Array data during 2001–2011 also show the presence of millihertz QPOs during some of the outbursts, and details of these QPOs are also reported. Possible models to explain the origin of the millihertz oscillations are examined. Similar QPOs, albeit at higher frequencies, have been reported from other neutron star and black hole sources, and both may have a common origin. Current models to explain the instability in the inner accretion disk causing the intense oscillations are discussed. [ABSTRACT FROM AUTHOR]

We present X-ray light curves of Cygnus X-3 as measured by the recently launched AstroSat satellite. The light curve folded over the binary period of 4.8 hr shows a remarkable stability over the past 45 years and we find that we can use this information to measure the zero point to better than 100 s. We revisit the historical binary phase measurements and examine the stability of the binary period over 45 years. We present a new binary ephemeris with the period and period derivative determined to an accuracy much better than previously reported. We do not find any evidence for a second derivative in the period variation. The precise binary period measurements, however, indicate a hint of short-term episodic variations in periods. Interestingly, these short-term period variations coincide with the period of enhanced jet activity exhibited by the source. We discuss the implications of these observations on the nature of the binary system. [ABSTRACT FROM AUTHOR]

AstroSat is a multi-wavelength satellite launched on 2015 September 28. The CZT Imager of AstroSat on its very first day of operation detected a long duration gamma-ray burst (GRB), namely GRB 151006A. Using the off-axis imaging and spectral response of the instrument, we demonstrate that the CZT Imager can localize this GRB correctly to about a few degrees, and it can provide, in conjunction with Swift, spectral parameters similar to those obtained from Fermi/GBM. Hence, the CZT Imager would be a useful addition to the currently operating GRB instruments (Swift and Fermi). Specifically, we argue that the CZT Imager will be most useful for the short hard GRBs by providing localization for those detected by Fermi and spectral information for those detected only by Swift. We also provide preliminary results on a new exciting capability of this instrument: the CZT Imager is able to identify Compton scattered events thereby providing polarization information for bright GRBs. GRB 151006A, in spite of being relatively faint, shows hints of a polarization signal at 100–300 keV (though at a low significance level). We point out that the CZT Imager should provide significant time resolved polarization measurements for GRBs that have fluence three times higher than that of GRB 151006A. We estimate that the number of such bright GRBs detectable by the CZT Imager is five to six per year. The CZT Imager can also act as a good hard X-ray monitoring device for possible electromagnetic counterparts of gravitational wave events. [ABSTRACT FROM AUTHOR]