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Search Results: 1 - 10 of 15674 matches for " DIG VIJAY SINGH "
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Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site
Dig Vijay Singh,Krishna Misra
Bioinformation , 2009,
Abstract: Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.
A Review of VF Controller for an Asynchronous Generator Based Wind Energy Conversion System
D.K.NISHAD,DIG VIJAY SINGH,DEEPAK SINGH
International Journal of Engineering Science and Technology , 2013,
Abstract: VF controller for wind energy conversion system employing a self-excited asynchronous generator, that has the capability for harmonic elimination, load balancing , and neutral current compensation along with voltage and frequency. This paper presents a review of VF controllers, other related economic and technical aspects, and their selection for specific applications. It is aimed at providing a broad perspectives or the status of VF controller for researchers and application engineers dealing with VF controlling issues. A list of more than 50 research publications on the subject is also appended for quick reference.
Evaluation of Non-Point Source N and P Loads in a Small Mixed Land Use Land Cover Watershed  [PDF]
Ashok Mishra, Rajendra Singh, Vijay P. Singh
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.24042
Abstract: Non-point source pollution (NPS) of water resources has become a major problem in recent years due to more human interactions and disturbances to natural landscapes. The problem can have more impacts in sub-humid subtropical regions where high intensity monsoon rains have greater effects on hydrologic proc-esses and thus the assessment of those effects is necessitated for strategic water resources and environmental management. Since spatial and temporal changes of NPS pollutants are difficult to assess on a watershed scale, the assessment can be done effectively using a suitable water quantity-quality model coupled with GIS and remote sensing that incorporates spatial variations. The objective of this study was to assess the N and P loads from a small mixed type watershed comprising different land use land covers with the aid of Soil and Water Assessment Tool (SWAT)-a hydrologic-water quality model. The model was calibrated for runoff and sediment transport and then simulation of associated N and P loads as NPS pollution was done and compared with measured values at the outlet of the watershed which is part of the DVC Command, Hazaribagh, India. The calibrated SWAT model was used to estimate the water soluble NO3-N, NH4-N, P, organic N and or-ganic P loads being transported as pollutants by runoff and percolated water. The estimates of these pollut-ants provided information on the extent of NPS pollution of water downstream. The results of the study re-veal that the NPS pollutant load in runoff varies with seasonal rainfall patterns and ranges from 2.57 to 4.52 kg/ha in case of NO3-N which accounts for a maximum load of 7661.40 kg of NO3-N in surface runoff from the watershed under study. The total loss of N from the watershed accounts for as high as 8.84 kg/ha, whereas the P load is 0.02 kg/ha. These losses can be as high as 14984.14 kg of total N and 50.85 kg of total P when estimated as NPS pollutants from the watershed. The study is therefore important to get an estimate of the extent of these pollutants and develop measures for mitigating the losses as nutrient as well as pollu-tion of water resources.
Ecohydrologically Driven Catchment Evaluation and Prioritization  [PDF]
Sivarajah Mylevaganam, Raghavan Srinivasan, Vijay P. Singh
Open Journal of Applied Sciences (OJAppS) , 2015, DOI: 10.4236/ojapps.2015.57033
Abstract: This study develops information based on index, and termed hydro-ecological-index, to represent the need of a riverine ecosystem characterized through a biologically relevant flow regime. The flow regime is defined by a set of parameters, called Indicators of Hydrologic Alteration. These parameters are predicted at the catchment scale by a hydrologic model, called Soil and Water Assessment Tool. Then the Maximum Entropy Ordered Weighted Averaging method is employed to aggregate non-commensurable biologically relevant flow regimes to develop hydro-ecological- index at the catchment scale. The resulting index reflects the variability of the need of the riverine ecosystem at catchment scale and thus different catchments can be evaluated and compared.
Long Term Soil and Water Assessment Tool (SWAT) Calibration from an Ecohydrology Perspective  [PDF]
Sivarajah Mylevaganam, Raghavan Srinivasan, Vijay P. Singh
Open Journal of Applied Sciences (OJAppS) , 2015, DOI: 10.4236/ojapps.2015.57035
Abstract: The performance on prediction by mathematical models which represent the conceived image of a system such as hydrology is oftentimes represented through calibration and verification processes. Oftentimes a best fit between observed and predicted flows is obtained through correlation coefficient (R2) and the Nash Sutcliffe model efficiency (NSE) by minimizing the average Root Mean Square Error (RMSE) of the observed versus simulated flows. However, these days, a new paradigm is emerging wherein accounting for the flow variability for the protection of freshwater biodiversity and maintenance of goods and services that rivers provide is paramount. Therefore, from an ecohydrology perspective, it is not clear if the existing method of model calibration meets the needs of the riverine ecosystem at its best. Thus, this study investigates and proposes a methodology using entropy theory to gage the calibration of Soil and Water Assessment Tool (SWAT) from an ecohydrology perspective characterized by the natural flow-regime paradigm: Indicators of Hydrologic Alteration.
String Cosmology with Magnetic field in Anisotropic Space-time
C. P. Singh,Vijay Singh
Physics , 2012,
Abstract: In this paper we study the effect of the magnetic field in string cosmology for a spatially homogenous and anisotropic Bianchi type -V space-time model. In order to study the effect of magnetic field, the standard form of the energy momentum tensor for cosmic strings is modified by including an additional term for magnetic field. The magnetic field is due to an electric current produced along the x-axis with infinite electrical conductivity. The field equations are solved for different string models such as geometric string (Nambu string), Takabayashi string (p-string) and Reddy string using string equation of state. We also find the solution for string models with uniform energy density. The physical and geometrical properties of each string model with and without magnetic field are discussed in detail.
Some Exact Solutions of Magnetized viscous model in String Cosmology
C. P. Singh,Vijay Singh
Physics , 2012,
Abstract: In this paper, we study anisotropic Bianchi-V universe with magnetic field and bulk viscous fluid in string cosmology. Exact solutions of the field equations are obtained by using the equation of state for a cloud of strings, and a relationship between bulk viscous coefficient and scalar expansion. The bulk viscous coefficient is assumed to be inversely proportional to the expansion scalar. It is interesting to examine the effects of magnetized bulk viscous string model in early and late stages of the evolution of the universe. This paper presents the different string models like geometrical (Nambu string), Takabayashi (p-string) and Reddy string models by taking certain physical conditions. We discuss the nature of the classical potential for viscous fluid with and without magnetic field. We find that the introduction of bulk viscosity with and without magnetic field results in rapid change in density parameters and in the classical potential. The presence of bulk viscosity prevents the universe to be empty in its future evolution. The other physical and geometrical aspects of each string model are discussed in detail.
Signal Scrambling Techniques for PAPR Reduction in OFDM Systems
Maan Singh,Vijay Kumar
International Journal of Engineering and Computer Science , 2013,
Abstract: In recent years, the communication industry has started focusing on fourth generation (4G) mobile communication systems. It is expected that 4G will provide a comprehensive and secure IP solution where voice, data, and multimedia can be offered to users at “anytime, anywhere” with higher data rates than previous generations. To improve spectrum efficiency and achieve as high as 100Mbps wireless transmission rate, 4G requires more advanced communication techniques to be employed. Multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) have, therefore, been adopted due to their superior performance. However, OFDM has few disadvantages; with the key one is high ratio of peak power of signal to average power is called peak-to-average power ratio; abbreviated as PAPR. It is preferred to have a minimum PAPR, as it will allow a higher average power to be transmitted for a fixed peak power; and thus, improving the overall signal to noise ratio at the receiver. Therefore, this paper investigates two signal scrambling techniques, namely, selected mapping (SLM) and partial transmit sequence (PTS) for the purpose of reducing PAPR. From the analysis, it is inferred that PTS method provides a better PAPR reduction performance compared to SLM method. However, the transmitter and receiver complexity is very high. Thus in practical applications, a tradeoff needs to be made between good performance and auxiliary information. It is also found that SLM algorithm is more suitable if system can tolerate more redundant information; otherwise, PTS algorithm is more acceptable when complexity becomes the first considering factor.
Spacer Optimization and Accurate Small-Signal Modeling of 90nm Gate Underlap SOI-MOSFETs for Low Power GHz Applications
Indra Vijay Singh
International Journal of Nano Devices, Sensors and Systems , 2013, DOI: 10.11591/ij-nano.v2i1.1934
Abstract: This paper presents the significance of gate-source/drain extension region (also known as underlap design) optimization in 90nm single gate (SG) Silicon-on-Insulator (SOI) MOSFET for low power GHz frequency applications. Using an optimal spacer s ( 0.8×LG, where LG is gate length), it has been found that the device exhibits intrinsic gain of 25 dB in low-moderate inversion region (VOD =VGS – VTH ≤ 90 mV, where VOD, VGS and VTH are the overdrive, gate and threshold voltages, respectively) at operating frequency of 20 GHz. An accurate (including non-quasi-static and extrinsic parasitics effects) small-signal model for the optimized device has been presented. The comparison of Y-parameters of 2D ATLAS with overall modeled value (up to 20 GHz) has shown an excellent matching (with an average error of ≤5%), whereas results from quasi-static (QS) predictive technology model (PTM) differ significantly (>20%). Optimized underlap device shows transit frequency fT and maximum frequency of oscillation fMAX, ~108 and ~130 GHz respectively, with noise figure (NF) ~2.8 dB and exhibits unilateral power gain (ULG) ~38 dB (VOD =90mV, drain-to-source current IDS 0.64mA and drain-to-source voltage VDS = 1V) at 20 GHz. Comparison with limited measured data suggest that simulated results are in well conformity, which suggest the possibility of use of underlap device technology in the design of key blocks such as low noise amplifier LNA and mixer for GHz applications. Key Words: Gate Underlap, silicon-on-Insulator, Non-Quasi-Static, Transconductance-to-Net-Charge Ratio (TCR), Low Power.
Gene therapy in ocular diseases
Singh Vijay,Tripathi Parul
Indian Journal of Ophthalmology , 2002,
Abstract: Gene therapy is a novel form of drug delivery that enlists the synthetic machinery of the patient′s cells to produce a therapeutic agent. Genes may be delivered into cells in vitro or in vivo utilising viral or non-viral vectors. Recent technical advances have led to the demonstration of the molecular basis of various ocular diseases. Ocular disorders with the greatest potential for benefit of gene therapy include hereditary diseases such as retinitis pigmentosa, tumours such as retinoblastoma or melanoma, and acquired proliferative and neovascular retinal disorders. Gene transfer into ocular tissues has been demonstrated with growing functional success and may develop into a new therapeutic tool for clinical ophthalmology in future.
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