A series of cobalt-doped nickel ferrite with composition of Ni
(1−
x)
Co
x
Fe
2O
4 with
x ranges from 0.0 to 0.8 (in steps of 0.2) was prepared by using standard ceramic technique. The confirmation ...of single-phase formation and structural analysis were carried out by employing X-ray diffraction technique. The electrical DC resistivity measurement was done by using usual two probe method in the temperature range from room temperature to 600
°C. Room temperature resistivity measurements show the decrease in resistivity with increase of cobalt concentration. The studies on resistivity as a function of temperature shows that all the sample obeys the semiconducting behavior. B–H hysteresis measurement was carried out at room temperature under the field of 2.4
kOe and this measurement with the increase of Co
2+concentration yields the monotonic increase of saturation magnetization (
M
s) and decrease in coercive field (
H
c) at higher Co
2+concentration (
x
>
0.4). Ferrites with such behavior are important for magnetic recording media. In view of this, we have studied the various properties of Co-doped Ni ferrite.
We report the Swift discovery of the nearby long, soft gamma-ray burst GRB100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of the ...event to be z= 0.0591 ± 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt emission with time-resolved γ-ray to X-ray spectroscopy and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini-South, Very Large Telescope and Hubble Space Telescope observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB100316D to a subsample of GRB-SNe. GRB100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB-SN connection can be gleaned. PUBLICATION ABSTRACT
The Soft X-ray focusing Telescope (SXT), India’s first X-ray telescope based on the principle of grazing incidence, was launched aboard the AstroSat and made operational on October 26, 2015. X-rays ...in the energy band of 0.3–8.0 keV are focussed on to a cooled charge coupled device thus providing medium resolution X-ray spectroscopy of cosmic X-ray sources of various types. It is the most sensitive X-ray instrument aboard the AstroSat. In its first year of operation, SXT has been used to observe objects ranging from active stars, compact binaries, supernova remnants, active galactic nuclei and clusters of galaxies in order to study its performance and quantify its characteriztics. Here, we present an overview of its design, mechanical hardware, electronics, data modes, observational constraints, pipeline processing and its in-orbit performance based on preliminary results from its characterization during the performance verification phase.
We report the Swift discovery of the nearby long, soft gamma-ray burst GRB 100316D, and the subsequent unveiling of its low-redshift host galaxy and associated supernova. We derive the redshift of ...the event to be z= 0.0591 ± 0.0001 and provide accurate astrometry for the gamma-ray burst (GRB) supernova (SN). We study the extremely unusual prompt emission with time-resolved γ-ray to X-ray spectroscopy and find that the spectrum is best modelled with a thermal component in addition to a synchrotron emission component with a low peak energy. The X-ray light curve has a remarkably shallow decay out to at least 800 s. The host is a bright, blue galaxy with a highly disturbed morphology and we use Gemini-South, Very Large Telescope and Hubble Space Telescope observations to measure some of the basic host galaxy properties. We compare and contrast the X-ray emission and host galaxy of GRB 100316D to a subsample of GRB-SNe. GRB 100316D is unlike the majority of GRB-SNe in its X-ray evolution, but resembles rather GRB 060218, and we find that these two events have remarkably similar high energy prompt emission properties. Comparison of the host galaxies of GRB-SNe demonstrates, however, that there is a great diversity in the environments in which GRB-SNe can be found. GRB 100316D is an important addition to the currently sparse sample of spectroscopically confirmed GRB-SNe, from which a better understanding of long GRB progenitors and the GRB-SN connection can be gleaned.
We present the Pan-STARRS1 discovery of the long-lived and blue transient PS1-11af, which was also detected by Galaxy Evolution Explorer with coordinated observations in the near-ultraviolet (NUV) ...band. Four epochs of spectroscopy reveal a pair of transient broad absorption features in the UV on otherwise featureless spectra. Blackbody fits to the spectral energy distribution are inconsistent with the cooling, expanding ejecta of a SN, and the velocities of the absorption features are too high to represent material in homologous expansion near a SN photosphere. A full disruption model predicts higher bolometric luminosities, which would require most of the radiation to be emitted in a separate component at high energies where we lack observations. Three deep non-detections in the radio with the Very Large Array over the first two years after the event set strict limits on the production of any relativistic outflow comparable to Swift J1644+57, even if off-axis.
The present work reports for the first time the use of Decaschistia trilobata Wight. as a reducing agent for synthesis of silver nanoparticles (AgNPs). D. trilobata is an endemic shrub and grows ...seasonally in dry tropical biome, evergreen forests in hilly terrain of western ghats. One of the most fascinating metallic nanoparticles utilized in biological applications is AgNPs. In present work green synthesis of stable silver nanoparticles using Decaschistia trilobata (Dt-AgNPs) leaves extract as well as quantitative analysis of phytochemicals. The synthesized Dt-AgNPs were characterized and evaluated for their antioxidant anti-inflammatory, antibacterial and dye reduction.
Display omitted
•Biosynthesis of AgNPs using Decaschistia trilobata leaf extract.•Dt-AgNPs were characterized by advanced instrumentation.•Dt-AgNPs shown Biological and Dye reduction activity.
Various methods for the degradation and detoxification of textile effluents have been developed in recent years and among these, advanced oxidation processes (AOPs) have been proven to be a ...successful way of degrading organically contaminated water into a useful form. The synchrotron X-ray (3–20 keV) irradiation-assisted AOP has been developed for the degradation of single and mixed colored industrial wastewater solution. Irradiation experiments were conducted on industrial effluents obtained straight from the cloth industries. The efficiency of AOP was measured by characterizing irradiated industrial wastewater solutions with optical, chemical, and biological characterization techniques. The UV-Vis spectroscopy and chemical oxidation demand (COD) results revealed that the wastewater was degraded and the degradation efficiency could be tailored by varying the X-ray dose. The complete decolorization and ∼ 85% removal in COD was obtained at the X-ray dose of 15000 mAs. Chemical species present in pristine and irradiated wastewater were analyzed using FTIR techniques. The FTIR spectra revealed the destruction of the aromatic ring and nitrogen linkage of wastewater under X-ray irradiation. The technique of liquid chromatography-mass spectroscopy (LC-MS) was employed to identify and quantify the unknown compounds present in pristine as well as X-ray irradiated wastewater solutions. Toxicity assays on gram-negative Escherichia coli (DH5α) clearly show detoxification of X-ray irradiated solutions. This study demonstrates a fast and effective approach for completely degrading and detoxifying industrial wastewater, and has a wide range of applications in environmental remediation.
•Synchrotron X-ray-assisted degradation of industrial wastewater was investigated.•Efficiency of AOP was assessed based on degradation, COD & toxicity of wastewater.•Synchrotron X-rays reduced 85% COD and 99% coloration of wastewater solutions.•Inhibition growth of E-Coli shows detoxification of wastewater after irradiation.•Synchrotron X-ray irradiation based AOP could be used for pollutant degradation.
Marek’s disease virus (MDV) causes a deadly lymphoproliferative disease in chickens, resulting in huge economic losses in the poultry industry. It has been suggested that MDV suppresses the induction ...of type I interferons and thus escapes immune control. Cholesterol 25-hydroxylase (CH25H), a gene that encodes an enzyme that catalyses cholesterol to 25-hydroxycholesterol (25-HC), is an interferon-stimulating gene (ISG) known to exert antiviral activities. Other oxysterols, such as 27-hydroxycholesterols (27-HC), have also been shown to exert antiviral activities, and 27-HC is synthesised by the catalysis of cholesterol via the cytochrome P450 enzyme oxidase sterol 27-hydroxylase A1 (CYP27A1). At 24 h post infection (hpi), MDV stimulated a type I interferon (IFN-α) response, which was significantly reduced at 48 and 72 hpi, as detected using the luciferase assay for chicken type I IFNs. Then, using RT-PCR, we demonstrated that chicken type I IFN (IFN-α) upregulates chicken CH25H and CYP27A1 genes in chicken embryo fibroblast (CEF) cells. In parallel, our results demonstrate a moderate and transient upregulation of CH25H at 48 hpi and CYP27A1 at 72hpi in MDV-infected CEF cells. A significant reduction in MDV titer and plaque sizes was observed in CEFs treated with 25-HC or 27-HC in vitro, as demonstrated using a standard plaque assay for MDV. Taken together, our results suggest that 25-HC and 27-HC may be useful antiviral agents to control MDV replication and spread.
Introduction
Infectious Bursal Disease Virus (IBDV) causes immunosuppression in chickens. While B-cell destruction is the main cause of humoral immunosuppression, bursal T cells from IBDV-infected ...birds have been reported to inhibit the mitogenic response of splenocytes, indicating that some T cell subsets in the infected bursa have immunomodulatory activities. CD4
+
CD25
+
TGFβ
+
cells have been recently described in chickens that have immunoregulatory properties and play a role in the pathogenesis of Marek’s Disease Virus.
Methods
To evaluate if CD4
+
CD25
+
TGFβ
+
cells infiltrated the bursa of Fabricius (BF) following IBDV infection, and influenced the outcome of infection, birds were inoculated at either 2 days or 2 weeks of age with vaccine strain (228E), classic field strain (F52/70), or PBS (mock), and bursal cell populations were quantified by flow cytometry.
Results
Both 228E and F52/70 led to atrophy of the BF, a significant reduction of Bu1
+
-B cells, and a significant increase in CD4
+
and CD8α
+
T cells in the BF, but only F52/70 caused suppression of immune responses to a test antigen in younger birds, and clinical signs in older birds. Virus was cleared from the BF more rapidly in younger birds than older birds. An infiltration of CD4
+
CD25
+
T cells into the BF, and elevated expression of bursal TGFβ-1
+
mRNA was observed at all time points following infection, irrespective of the strain or age of the birds, but CD4
+
TGFβ
+
cells and CD4
+
CD25
+
TGFβ
+
cells only appeared in the BF at 28 dpi in younger birds. In older birds, CD4
+
TGFβ
+
cells and CD4
+
CD25
+
TGFβ
+
cells were present at earlier time points, from 7dpi following 228E infection, and from 14 and 28 dpi following F52/70 infection, respectively.
Discussion
Our data suggest that an earlier infiltration of CD4
+
TGFβ
+
cells into the BF correlated with a delayed clearance of virus. However, the influx of CD4
+
TGFβ
+
cells and CD4
+
CD25
+
TGFβ
+
into the BF did not correlate with increased pathogenicity, or immunosuppression.
MAXI J1659−152 was discovered on 2010 September 25 as a new X-ray transient, initially identified as a gamma-ray burst, but was later shown to be a new X-ray binary with a black hole as the most ...likely compact object. Dips in the X-ray light curves have revealed that MAXI J1659−152 is the shortest period black hole candidate identified to date. Here we present the results of a large observing campaign at radio, submillimetre, near-infrared (nIR), optical and ultraviolet (UV) wavelengths. We have combined this very rich data set with the available X-ray observations to compile a broad-band picture of the evolution of this outburst. We have performed broad-band spectral modelling, demonstrating the presence of a spectral break at radio frequencies and a relationship between the radio spectrum and X-ray states. Also, we have determined physical parameters of the accretion disc and put them into context with respect to the other parameters of the binary system. Finally, we have investigated the radio-X-ray and nIR/optical/UV-X-ray correlations up to ∼3 yr after the outburst onset to examine the link between the jet and the accretion disc, and found that there is no significant jet contribution to the nIR emission when the source is in the soft or intermediate X-ray spectral state, consistent with our detection of the jet break at radio frequencies during these states.
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