Time filter

Source Type

Bhardwaj R.,Institute of Nuclear Medicine and Allied Sciences | Sharma P.K.,Institute of Nuclear Medicine and Allied Sciences | Sharma P.K.,Guru Gobind Singh Indraprastha University | Jadon S.P.S.,Shri Varshneya College | And 2 more authors.
Tumor Biology | Year: 2012

Previously, we have shown that a combination of metabolic modifiers 2-deoxy-d-glucose (2-DG) and 6-aminonicotinamide (6-AN) results in oxidative stress mediated radiosensitization of malignant cells via mitochondrial dysfunction and non-coordinated expression of antioxidant defense, besides inhibition of repair and recovery. In the present study, our objective was to study, in a panel of human malignant cells of various origins (lung carcinoma, squamous carcinoma, oral carcinoma, and glioblastoma), if the inhibitory activity of combination (2-DG+6-AN+2Gy) against tumor growth could be considered a general phenomenon and to determine its effect on the cell cycle. The results revealed that combination (2-DG+6-AN+2Gy) treatment result in significant cell growth inhibition and induced ROS generation in all cancer cells studied. The anti-proliferative effect was related to the ability of combination (2-DG+6-AN+2Gy) to provoke growth inhibition at the G2/M arrest and apoptosis. Furthermore, combination (2-DG+6-AN+2Gy) induced G2/M arrest is closely correlated to decreased cyclin A, cyclin B1, and cdc2 levels. © 2012 International Society of Oncology and BioMarkers (ISOBM).

Chattopadhyay A.,Indian School of Mines | Gupta S.,Indian School of Mines | Kumari P.,Jaypee Institute of Information Technology | Sharma V.K.,Defence Research and Development Organisation
International Journal for Numerical and Analytical Methods in Geomechanics | Year: 2013

SUMMARY: The study of surface wave in a layered medium has their possible application in geophysical prospecting. In the present work, dispersion equation for torsional wave in an inhomogeneous isotropic layer between inhomogeneous isotropic half-spaces has been derived. Two cases are discussed separately for torsional wave propagation in inhomogeneous layer between homogeneous and non-homogeneous half-spaces, respectively. Further, two possible modes for torsional wave propagation are obtained in case of inhomogeneous layer sandwiched between non-homogeneous half-spaces. Closed form solutions for displacement in the layer and half-spaces are obtained in each case. The study reveals that the layer width, layer inhomogeneity, frequency of inhomogeneity, as well as inhomogeneity in the half-space has significant effect on the propagation of torsional surface waves. Displacement and implicit dispersion equation for torsional wave velocities are expressed in terms of Heun functions and their derivatives. Effects of inhomogeneity on torsional wave velocity are also discussed graphically by plotting the dimensionless phase velocity against dimensionless and scaled wave number for different values of inhomogeneity parameter. © 2012 John Wiley & Sons, Ltd.

Bhardwaj A.,TERI University | Bhardwaj A.,Snow and Avalanche Study Establishment Research and Development Center | Joshi P.K.,TERI University | Snehmani,Snow and Avalanche Study Establishment Research and Development Center | And 4 more authors.
Cold Regions Science and Technology | Year: 2014

Supraglacial debris significantly hampers the mapping of glaciers using remote sensing data. A semi-automated approach for the mapping of debris-covered glacier was applied, which combined the inputs from thermal and optical remote sensing data and the Digital Elevation Model (DEM) derived morphometric parameters. A thermal mask that delineates the supraglacial debris extent was generated by the thresholding of surface temperature layer obtained from Landsat TM/ETM. + thermal band satellite data. The extent of clean glacier ice was identified by band ratioing and thresholding of TM/ETM. + 4 and TM/ETM. + 5 bands. Morphometric parameters like slope, plan curvature and profile curvature were rearranged in similar surface groups using the technique of cluster analysis. All these masks were vectorized and final classification maps were generated using geographic information system (GIS) overlay operations. The areal extent of semi-automated outlines of Hamtah and Patsio Glaciers derived from cluster analysis varied from manually derived outline using pan-sharpened Landsat ETM. + September 2000 image by -. 1.3% and -. 1.6%, respectively. Year 2011 classification map for Patsio Glacier was compared with the field observations and a high correlation and overall accuracy (~. 91%) were observed. The same classification methodology was adopted for images of years 2000 and 1989 for Patsio Glacier to observe the effects of varying snow cover patterns on adopted methodology. Also the methodology was adopted and verified for Hamtah Glacier, with different geometry and terrain conditions as compared to Patsio Glacier. Although the spatial resolution limitation of ASTER GDEM and Landsat TM/ETM. + thermal band limits the automated mapping of small debris-covered glaciers, the outcomes are still favorable enough to apply such methodologies for mapping different types of debris-covered glaciers in the future. © 2014 Elsevier B.V.

Sankar H.R.,Gandhi Institute of Technology and Management | Srikant R.R.,Gandhi Institute of Technology and Management | Krishna P.V.,Gandhi Institute of Technology and Management | Rao V.B.,Defence Research and Development Organisation | Babu P.B.,National Institute of Technology Warangal
International Journal of Automotive and Mechanical Engineering | Year: 2013

Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm) when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%. © Universiti Malaysia Pahang.

Ghosh S.,Defence Research and Development Organisation | Mukhopadhyay S.,Indian Institute of Technology Kharagpur
IEEE Transactions on Aerospace and Electronic Systems | Year: 2011

In this paper an acceleration model and a jerk model are proposed for estimation of the kinematic state of reentry ballistic targets (RBTs) using extended Kalman filters (EKF). The models proposed here use the equations of target kinematics only and do not assume any model parameterization for variation of the ballistic coefficient and air density a priori, as found in the literature. The novelty lies in estimation of the ratio (γ) of air density and ballistic coefficient and its time derivatives using a separate Kalman filter (KF) (γ-filter) which utilizes pseudo measurements of γ computed from the velocity and acceleration estimated by the EKF at each time step. The parameter γ and its derivatives estimated by the γ-filter are, in turn, used for the estimation of position, velocity, acceleration, and jerk in the EKF. The use of the pseudo measurements of γ makes the algorithms inherently adaptive to variations of the ballistic coefficient and air density during reentry. A comparative assessment of several dynamic models for reentry of ballistic targets reported in the literature and those proposed here demonstrates that the estimation errors in velocity and acceleration are significantly less for the proposed models compared with the existing ones. © 2011 IEEE.

Discover hidden collaborations