Showing papers by "Somnath Ghosh published in 2008"

Thorium-induced oxidative stress mediated toxicity in mice and its abrogation by diethylenetriamine pentaacetate.

Abstract: Purpose: Thorium (232Th, IV) preferentially accumulates in the liver, femur and spleen, which necessitates evaluation of its toxic effect in these organs. The present study was aimed at evaluation of liver function, oxidative stress and histological alterations in these organs.Materials and methods: Swiss albino mice were administered either with Thorium nitrate (10 mg/kg body weight/day equivalent to 1090 pCi/kg body weight/day) for 30 days (1/40th dose of LD50/30; the dose of thorium required to kill 50% of the test cohort within 30 days) intraperitoneally or with calcium salt of diethylenetriamine pentaacetate (Ca-DTPA, 100 μmole/kg body/weight) intravenously or both. Liver function tests and oxidative damage was assessed. The concentration of Th in the tissues was determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) method.Results: Administration of Th prevented the increase in the body and liver weight and altered liver functions. Th treatment to mice showed a decrease in t...

Role of iNOS in bystander signaling between macrophages and lymphoma cells.

Abstract: Purpose The present report describes the bystander effects of radiation between similar and dissimilar cells and the role of iNOS in such communication. Materials and Methods EL-4 and RAW 264.7 cells were exposed to 5 Gy γ-irradiation. The medium from irradiated cells was transferred to unirradiated cells. Results Irradiated EL-4 cells as well as those cultured in the presence of medium from γ-irradiated EL-4 cells showed an upregulation of NF-κB, iNOS, p53, and p21/waf1 genes. The directly irradiated and the bystander EL-4 cells showed an increase in DNA damage, apoptosis, and NO production. Bystander signaling was also found to exist between RAW 264.7 (macrophage) and EL-4 (lymphoma) cells. Unstimulated or irradiated RAW 264.7 cells did not induce bystander effect in unirradiated EL-4 cells, but LPS stimulated and irradiated RAW 264.7 cells induced an upregulation of NF-κB and iNOS genes and increased the DNA damage in bystander EL-4 cells. Treatment of EL-4 or RAW 264.7 cells with L-NAME significantly reduced the induction of gene expression and DNA damage in the bystander EL-4 cells, whereas treatment with cPTIO only partially reduced the induction of gene expression and DNA damage in the bystander EL-4 cells. Conclusions It was concluded that active iNOS in the irradiated cells was essential for bystander response.

Room temperature ferromagnetism in 200 KeV Nickel ion implanted Zinc oxide film

Abstract: Room temperature ferromagnetism is observed in 200 keV Ni (∼3%) implanted ZnO films deposited on Si (100) substrate by vapour phase transport process. Crystalline phases of ZnO and ZnO:Ni films are determined by grazing angle X-ray diffraction (GAXRD) technique. Using X-ray Fluroscence (XRF) technique the presence of Ni in ZnO matrix is detected. Magnetic measurement by alternating gradient magnetometer (AGM) shows a clear hysterisis loop at room temperature with a saturation magnetization of 0.025 emu/cm3, remnant magnetization of 0.0030 emu/cm3 and coercive field of 53.14 Oe. Surface morphological study by atomic force microscope (AFM) of the films shows ∼73% enhancement of grain size and increase in surface areal density of grains. This is associated with almost 10 times reduction in resistivity value of the Ni implanted ZnO films as compared to its unimplanted counterpart as revealed by four probe resistivity technique. The result is understood on the basis of an exchange interaction of the charge car...

An Energy Efficient Wireless Sensor MAC Protocol with Global Sleeping Schedule

Abstract: Wireless sensor networks (WSNs) aim to fulfill the need for reliable and fault-tolerant sensing services. This has made wireless sensor networks a very active research area. SMAC is an energy efficient sensor MAC protocol. An S-MAC problem is that border nodes have to adopt multiple sleeping schedules, which speed up the energy depletion of border nodes. In this paper, S-MACL is proposed to overcome this problem. In S-MACL, a global sleeping schedule is used. The simulations result shows that S-MACL achieves a greater level of energy efficiency than S-MAC.

2,2'-Diazinodimethylidyne)di-o-phenyl-ene) dibenzoate.

Abstract: The title compound, C28H20N2O4, was synthesized by the reaction of 2-(hydrazonometh­yl)phenyl benzoate with iodine. The mol­ecule possesses a crystallographically imposed center of symmetry at the mid-point of the hydrazine N—N bond. The substituents at the ends of the C=N bonds adopt an E,E configuration. Inter­molecular C—H⋯π(arene) hydrogen bonds and aromatic π–π stacking inter­actions [centroid–centroid distance 3.900 (1) A] link the mol­ecules into (100) sheets. In addition, there is an inter­molecular C—H⋯O hydrogen-bond inter­action.

Synthesis of nano-dimensional ZnO and Ga doped ZnO thin films by vapor phase transport and study as transparent conducting oxide.

Abstract: We report synthesis of polycrystalline ZnO and Ga doped ZnO (ZnO:Ga) thin films (approximately 80 nm) on Si and quartz substrates in a non-vacuum muffle furnace, a simple and cost-effective route, without any catalyst/reactive carrier gases, at relatively low processing temperature of 550 degrees C. The crystalline phases of the films are identified by grazing angle X-ray diffraction (GAXRD). The growth of ZnO films is examined with scanning electron microscope (SEM) as a function of deposition time. An optical transmission of approximately 90% is observed for pure ZnO film having a resistivity of approximately 2.1 Omega-cm as measured by van der Pauw technique. Doping with Ga results in single phase ZnO:Ga films, retaining an optical transmission of about 80% and three orders of magnitude decrease in resistivity as compared to pure ZnO film.