Elemental Analysis of Glass and Bakelite Electrodes Using PIXE Facility

The evolution of particle detectors dates back to the discovery of X-rays and radioactivity in 1890s. In detector history, the Resistive Plate Chambers (RPCs) are introduced in early 1980s. An RPC is a gaseous detector made up of two parallel electrodes having high resistivity like that of glass and bakelite. Currently several high energy physics experiments are using RPC-based detector system due to robustness and simplicity of construction. In each and every experiment, RPCs have to run continuously for several years. So, it demands an in-depth characterization of the electrode materials. In the present study, an elemental analysis of locally available glass and bakelite samples is done using PIXE facility available at Panjab University Cyclotron, Chandigarh. PIXE measurements are done using 2.7 MeV proton beam incident on the electrode sample target. The constituent elements present in these electrode samples are reported.Comment: 4 pages, 1 figures, 1 table; Presented in XXII DAE-BRNS High Energy Physics Symposium 201

Developmental Stability: A Major Role for Cyclin G in Drosophila melanogaster

Morphological consistency in metazoans is remarkable given the pervasive occurrence of genetic variation, environmental effects, and developmental noise. Developmental stability, the ability to reduce developmental noise, is a fundamental property of multicellular organisms, yet its genetic bases remains elusive. Imperfect bilateral symmetry, or fluctuating asymmetry, is commonly used to estimate developmental stability. We observed that Drosophila melanogaster overexpressing Cyclin G (CycG) exhibit wing asymmetry clearly detectable by sight. Quantification of wing size and shape using geometric morphometrics reveals that this asymmetry is a genuine—but extreme—fluctuating asymmetry. Overexpression of CycG indeed leads to a 40-fold increase of wing fluctuating asymmetry, which is an unprecedented effect, for any organ and in any animal model, either in wild populations or mutants. This asymmetry effect is not restricted to wings, since femur length is affected as well. Inactivating CycG by RNAi also induces fluctuating asymmetry but to a lesser extent. Investigating the cellular bases of the phenotypic effects of CycG deregulation, we found that misregulation of cell size is predominant in asymmetric flies. In particular, the tight negative correlation between cell size and cell number observed in wild-type flies is impaired when CycG is upregulated. Our results highlight the role of CycG in the control of developmental stability in D. melanogaster. Furthermore, they show that wing developmental stability is normally ensured via compensatory processes between cell growth and cell proliferation. We discuss the possible role of CycG as a hub in a genetic network that controls developmental stability

Preliminary results from India-based neutrino observatory detector R&D programme

We are currently developing and studying the performance of glass RPC prototypes, under the INO detector R&D programme. While we were successful in building and characterising a large number of chambers using local glass, these have met with severe aging problems after a few months of continuous operation. We have then built a couple of RPCs using a Japanese glass. We report in this paper on our long term stability tests of these RPCs. We also present some of our recent results on tracking of cosmic ray muons in a stack of glass RPCs

INO prototype detector and data acquisition system

India-based Neutrino Observatory (INO) collaboration is proposing to build a 50 kton magnetised iron calorimetric (ICAL) detector in an underground laboratory to be located in South India. Glass resistive plate chambers (RPCs) of about 2 m x 2 m in size will be used as active elements for the ICAL detector. As a first step towards building the ICAL detector, a 35 ton prototype of the same is being set up over ground to track cosmic muons. Design and construction details of the prototype detector and its data acquisition system will be discussed. Some of the preliminary results from the detector stack will also be highlighted. (C) 2009 Elsevier B.V. All rights reserved

Testing of the Paris LaBr3-NaI phoswich detector with high energy gamma-rays

We report on tests of LaBr3:Ce-NaI:Tl phoswich detectors with-rays at various γ-ray energies, up to 22.56 MeV, using radioactive sources and nuclear reactions induced by proton beams delivered by accelerators at IFJ PAN Kraków and PLF Mumbai. Two-dimensional analysis of complex waveforms recorded with digital electronics is compared to analog discrimination methods. Both approaches allow to resolve the LaBr3:Ce and NaI:Tl signal components, and to construct clean associated γ-ray spectra. A digital algorithm to be implemented for the PARIS scintillator array is investigated

L-Carnitine preserves endothelial function in a lamb model of increased pulmonary blood flow

BACKGROUND: In our model of congenital heart disease (CHD) with increased pulmonary blood flow (Shunt), we have recently shown a disruption in carnitine homeostasis, associated with mitochondrial dysfunction and decreased eNOS/Hsp90 interactions that contribute to eNOS uncoupling, increased superoxide levels, and decreased bioavailable NO. Thus, we undertook this study to test the hypothesis that L-carnitine therapy would maintain mitochondrial function, and NO signaling. METHODS: Thirteen fetal lambs underwent in utero placement of an aortopulmonary graft. Immediately following delivery, lambs received daily treatment with oral L-carnitine or its vehicle. RESULTS: L-carnitine-treated lambs had decreased levels of acyl carnitine, and a reduced acyl carnitine: free carnitine ratio compared to vehicle treated Shunt lambs. These changes correlated with increased carnitine acetyl transferase (CrAT) protein and enzyme activity and decreased levels of nitrated CrAT. The lactate: pyruvate ratio was also decreased in L-carnitine-treated lambs. Hsp70 protein levels were significantly decreased and this correlated with increases in eNOS/Hsp90 interactions, NOS activity, NOx levels, and a significant decrease in eNOS-derived superoxide. Further, acetylcholine significantly decreased left pulmonary vascular resistance (PVR) only in L-carnitine-treated lambs. CONCLUSION: L-carnitine therapy may improve the endothelial dysfunction noted in children with CHD, and has important clinical implications that warrant further investigation