Radiation Biology and Radiation Countermeasures

There is a growing concern of radiation injuries to the public and various professionals due to nuclear proliferation and enhanced terrorist activity as well as the risk of exposure in medical practice during radiation therapy and radiodiagnostics. Therefore, development of effective medical countermeasures against radiological and nuclear scenarios is of immense importance to the defence of all nations and for ensuring the safety of professionals and patients susceptible to radiation exposure.Defence Science Journal, 2011, 61(2), pp.97-98, DOI:http://dx.doi.org/10.14429/dsj.61.83

Radiation Biology and Radiation Countermeasures

There is a growing concern of radiation injuries to the public and various professionals due to nuclear proliferation and enhanced terrorist activity as well as the risk of exposure in medical practice during radiation therapy and radiodiagnostics. Therefore, development of effective medical countermeasures against radiological and nuclear scenarios is of immense importance to the defence of all nations and for ensuring the safety of professionals and patients susceptible to radiation exposure.Defence Science Journal, 2011, 61(2), pp.97-98, DOI:http://dx.doi.org/10.14429/dsj.61.83

Limits on the AGN activities in X-ray underluminous galaxy groups

We have observed four X-ray underluminous groups of galaxies using the Giant Meterwave RadioTelescope. The groups NGC 524, 720, 3607, and 4697 are underluminous in relation to the extrapolation of the Lx - T relation from rich clusters and do not show any evidence of current AGN activities that can account for such a departure. The GMRT observations carried out at low frequencies (235 and 610 MHz) were aimed at detecting low surface brightness, steep-spectrum sources indicative of past AGN activities in these groups. No such radio emissions were detected in any of these four groups. The corresponding upper limits on the total energy in relativistic particles is about 3 X 10$^{57}$ erg. This value is more than a factor of 100 less than that required to account for the decreased X-ray luminosities (or, enhanced entropies) of these four groups in the AGN-heating scenario. Alternatively, the AGN activity must have ceased about 4 Gyr ago, allowing the relativistic particles to diffuse out to such a large extent (about 250 kpc) that their radio emission could have been undetected by the current observations. If the latter scenario is correct, the ICM was pre-heated before the assembly of galaxy clusters.Comment: 10 pages, 3 figures, accepted for publication in ApJ Letter

Safety and effectiveness of tranexamic acid in reduction of post-partum hemorrhage in patients undergoing caesarean section in tertiary care hospital of Southern India

Background: Obstetric haemorrhage is a leading cause of premature maternal mortality, accounting for at least 100,000 deaths each year worldwide. Tranexamic acid has been shown to reduce uterine blood loss in non-surgical aspect. The aim of the study is to evaluate the safety and effectiveness of TXA in prevention of post-partum hemorrhage in patients undergoing caesarean delivery and to compare the secondary clinical outcomes.Methods: In this prospective observational cross-sectional study, 50 pregnant women undergoing CD were selected in random pattern and divided into control and study group of 25 patients each, in the department of obstetrics and gynaecology in Sri. Siddhartha medical college, Tumakuru from November 2019 to October 2021. The study group were given 1 g of TXA intravenously and the control group did not receive TXA. All the pregnant women received 20 units of oxytocin following delivery.Results: Mean of the total blood loss in the study group was 67 % less than the control group. Secondary clinical outcomes such as need for blood transfusion, other surgical measures to stop bleeding were comparatively less in study group compared to control groups. To note, no significant difference in duration of hospital stay was found between two groups.Conclusions: Our study suggests that, a safe dose of 1g IV tranexamic acid prior to caesarean section has an effective role in reducing blood loss and significantly improved blood loss–related secondary clinical outcomes with fewer side effects.

Arp 65 interaction debris: massive HI displacement and star formation

Context: Pre-merger interactions between galaxies can induce significant changes in the morphologies and kinematics of the stellar and ISM components. Large amounts of gas and stars are often found to be disturbed or displaced as tidal debris. This debris then evolves, sometimes forming stars and occasionally tidal dwarf galaxies. Here we present results from our HI study of Arp 65, an interacting pair hosting extended HI tidal debris. Aims: In an effort to understand the evolution of tidal debris produced by interacting pairs of galaxies, including in situ star and tidal dwarf galaxy formation, we are mapping HI in a sample of interacting galaxy pairs. The Arp 65 pair is one of them. Methods: Our resolved HI 21 cm line survey is being carried out using the Giant Metrewave Radio Telescope (GMRT). We used our HI survey data as well as available SDSS optical, Spitzer infra-red and GALEX UV data to study the evolution of the tidal debris and the correlation of HI with the star-forming regions within it. Results: In Arp 65 we see a high impact pre-merger interaction involving a pair of massive galaxies (NGC 90 and NGC 93) that have a stellar mass ratio of ~ 1:3. The interaction, which probably occurred ~ 1.0 -- 2.5 $\times$ 10$^8$ yr ago, appears to have displaced a large fraction of the HI in NGC 90 (including the highest column density HI) beyond its optical disk. We also find extended ongoing star formation in the outer disk of NGC 90. In the major star-forming regions, we find the HI column densities to be ~ 4.7 $\times$ 10$^{20}$ cm$^{-2}$ or lower. But no signature of star formation was found in the highest column density HI debris, SE of NGC 90. This indicates conditions within the highest column density HI debris remain hostile to star formation and it reaffirms that high HI column densities may be a necessary but not sufficient criterion for star formation.Comment: Accepted in A&

Chemical Radioprotectors

Protection of biological systems against radiation damage is of paramount importance during accidental and unavoidable exposure to radiation. Several physico-chemical and biological factors collectively contribute to the damage caused by radiation and are, therefore, targets for developing radioprotectors. Work on the development of chemicals capable of protecting biological systemsfrom radiation damage was initiated nearly six decades ago with cysteine being the first molecule to be reported. Chemicals capable of scavenging free radicals, inducing oxygen depletion,antioxidants and modulators of immune response have been some of the radioprotectors extensively investigated with limited success. Mechanism of action of some chemical radioprotectors and their combinations have been elucidated, while further understanding is required in many instances. The present review elaborates on structure-activity relationship of some of the chemical radioprotectors, their evaluation, and assessment, limitation, and future prospects

WSRT Ultra-Deep Neutral Hydrogen Imaging of Galaxy Clusters at z=0.2, a Pilot Survey of Abell 963 and Abell 2192

A pilot study with the powerful new backend of the Westerbork Synthesis Radio Telescope (WSRT) of two galaxy clusters at z=0.2 has revealed neutral hydrogen emission from 42 galaxies. The WSRT probes a total combined volume of 3.4x10^4 Mpc^3 at resolutions of 54x86 kpc^2 and 19.7 km/s, surveying both clusters and the large scale structure in which they are embedded. In Abell 963, a dynamically relaxed, lensing Butcher-Oemler cluster with a high blue fraction, most of the gas-rich galaxies are located between 1 and 3 Mpc in projection, northeast from the cluster core. Their velocities are slightly redshifted with respect to the cluster, and this is likely a background group. None of the blue galaxies in the core of Abell 963 are detected in HI, although they have similar colors and luminosities as the HI detected galaxies in the cluster outskirts and field. Abell 2192 is less massive and more diffuse. Here, the gas-rich galaxies are more uniformly distributed. The detected HI masses range from 5x10^9 to 4x10^10 Msun. Some galaxies are spatially resolved, providing rudimentary rotation curves useful for detailed kinematic studies of galaxies in various environments. This is a pilot for ultra-deep integrations down to HI masses of 8x10^8 Msun, providing a complete survey of the gas content of galaxies at z=0.2, probing environments ranging from cluster cores to voids.Comment: 5 pages, 6 figures + 1 Plate, accepted for publication in the Astrophysical Journal Letter

Flow-cytometric Analysis of Bacillus anthracis Spores

Flow-cytometric technique has been established as a powerful tool for detection andidentification of microbiological agents. Unambiguous and rapid detection of Bacillus anthracisspores has been reported using immunoglobulin G-fluorescein isothiocyanate conjugate againstlive spores. In addition to the high sensitivity, the present technique could differentiate betweenspores of closely related species, eg, Bacillus cereus and Bacillus subtilis using fluorescenceintensity. The technique can be used for detection of live as well as inactivated spores makingit more congenial for screening of suspected samples of bioterrorism