Bangalore, India

Karnatak University
Bangalore, India

Karnataka University was established at Dharwad in the Indian state of Karnataka in October 1949. It had its official inauguration in March 1950. The campus spans 750 acres . Dr. D. C. Pavate was the vice-chancellor from 1954 to 1967. The rapid development of the institution is credited to him.The university was recognized with the "Potential for Excellence" by the University Grants Commission. The university is the second oldest, after University of Mysore, in the state of Karnataka.H. B. Walikar is the vice-chancellor of the university. Wikipedia.

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Abbar J.C.,Karnatak University | Nandibewoor S.T.,Karnatak University
Colloids and Surfaces B: Biointerfaces | Year: 2013

An electrochemical method has been described for the voltammetric oxidation and determination of an antihyperlipoproteinemic drug, atorvastatin (ATOR), at a carbon paste electrode (CPE) in the presence of an enhancing agent, cetyltrimethyl ammonium bromide (CTAB) using cyclic and differential pulse voltammetry (DPV). The results indicated that the voltammetric response of ATOR was improved distinctly in the low concentration of CTAB, suggesting that CTAB exhibits noticeable enhancement effect to the determination of ATOR. The dependence of current on pH, concentration and scan rate were investigated to optimize the experimental conditions for the determination of ATOR. The anodic peak was characterized and the process was adsorption-controlled. The number of electrons transferred in the oxidation process was calculated and a plausible oxidation mechanism was proposed. In the range of 0.05-10 μM, the current measured by DPV presents a good linear property as a function of the concentration of ATOR with a detection limit of 4.08. nM with good selectivity and sensitivity. The proposed method was successfully applied to ATOR determination in pharmaceutical samples and urine as a real sample. This method can be employed in clinical analysis, quality control and routine determination of drugs in pharmaceutical formulations. © 2013 Elsevier B.V.

Kubakaddi S.S.,Karnatak University | Bhargavi K.S.,Karnatak University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

Phonon-drag thermopower Sg is theoretically studied in a bilayer graphene (BLG). Two-dimensional (2D) electrons with chiral property, finite effective mass, and parabolic dispersion are assumed to interact with the 2D acoustic phonons having a linear dispersion via deformation-potential coupling. A comparison is made with the very recent experimental results of Nam [arXiv:1005.4739 (unpublished)] for 30≤T≤70 K. Numerically Sg is studied as a function of temperature T, electron concentration ns, and phonon mean-free path. T3 behavior of Sg at very low T changes gradually to sublinear at higher T and the effect of chiral property of the electrons is seen explicitly. We suggest the possibility of significant enhancement of Sg at lower carrier concentrations by increasing the linear dimension of the sample and reducing its edge roughness. We find that Sg in BLG is enhanced by a factor of 7 compared with the magnitude of Sg in monolayer graphene, for ns =0.5× 1012 cm -2 in the Bloch-Grüneisen (BG) regime. In BG regime S g ∼ T3, a manifestation of 2D phonons with linear dispersion and Sg ∼ns-3/2, a characteristic of 2D electrons with parabolic dispersion. A comparison is also made with the results in conventional and ideal 2D systems. Sg is found to be very significant in comparison with the diffusion thermopower Sd and the latter is shown to be ∼T, ns-1 at low T and high ns. Herring's law, Sg μp ∼ T-1, relating phonon-limited mobility μp to Sg, is found to be valid in BLG. © 2010 The American Physical Society.

Gowda J.I.,Karnatak University | Nandibewoor S.T.,Karnatak University
Electrochimica Acta | Year: 2014

Paclitaxel, an anticancer drug was electrochemically studied in phosphate buffer at different pH using graphite pencil electrode. For analytical purpose, a well resolved irreversible diffusion controlled voltammetric peak was obtained in pH 7 phosphate buffer solution of ionic strength 0.2 M at 1.214 V for cyclic voltammetry. According to the linear relationship between the peak current and the paclitaxel concentration, differential pulse voltammetric method was developed for its quantitative determination in pharmaceuticals and human biological fluids. The linear response was obtained in the range of 4.0 × 10-7 to 3.0 × 10-6 M with a detection limit of 2.46 × 10-9 M. Precision and accuracy of the developed method was checked by recovery studies. The proposed method was successfully applied to the individual injection dosage form and human biological fluids.© 2013 Elsevier Ltd. All rights reserved.

Hodlur R.M.,Karnatak University | Rabinal M.K.,Karnatak University
Composites Science and Technology | Year: 2014

Nano-flakes of graphene can be suitably anchored on a polymer surface to create functionally more active material. Here, a simple method is reported for uniform coating of graphite-oxide onto flexible polyurethane foam and its further conversion to graphene-polyurethane composite. As prepared foam is quite flexible, highly compressible, homogeneous and electrically conducting that exhibits high pressure sensitivity. The material is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis to study the morphology, chemical interaction between constituent phases and thermal stability respectively. These studies confirm that graphene is strongly immobilized on polyurethane surface by chemical linkage. The influence of applied pressure on electrical conductivity shows that current increases by more than five orders of magnitude for a small change in pressure (just 0.5 atmospheres) yielding pressure sensitivity of 4×105/atmosphere. © 2013 Elsevier Ltd.

Punith R.,Karnatak University | Seetharamappa J.,Karnatak University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

The present study employed different optical spectroscopic techniques viz., fluorescence, FTIR, circular dichroism (CD) and UV-vis absorption spectroscopy to investigate the mechanism of interaction of an anticancer drug, anastrozole (AZ) with transport proteins viz., bovine serum albumin (BSA) and human serum albumin (HSA). The drug, AZ quenched the intrinsic fluorescence of protein and the analysis of results revealed the presence of dynamic quenching mechanism. The binding characteristics of drug-protein were computed. The thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°) were calculated to be +92.99 kJ/mol and +159.18 J/mol/K for AZ-BSA and, +99.43 kJ/mol and +159.19 J/mol/K for AZ-HSA, respectively. These results indicated that the hydrophobic forces stabilized the interaction between the drug and protein. CD, FTIR, absorption, synchronous and 3D fluorescence results indicated that the binding of AZ to protein induced structural perturbation in both serum albumins. The distance, r between the drug and protein was calculated based on the theory of Förster's resonance energy transfer and found to be 5.9 and 6.24 nm, respectively for AZ-BSA and AZ-HSA. © 2012 Elsevier B.V. All rights reserved.

Singh V.P.,Karnatak University | Badiger N.M.,Karnatak University
Annals of Nuclear Energy | Year: 2014

Gamma ray and neutron shielding properties of some alloy materials, CS-516, SS-403, SS-410, SS-316, SS-316L, SS-304L, Incoloy-600, Monel-400 and Cupero-Nickel were studied in the present work. Gamma shielding effectiveness of the alloys was studied by calculation of mass attenuation coefficient, half-value layer and exposure buildup factor (EBF). The EBFs of the alloys were calculated by GP fitting formula for photon energy 0.015-15 MeV up to 40 mfp penetration depth. Fast neutron removal cross section of the alloys was calculated by partial density method. Cupero-Nickel was found to be best shielding for gamma rays. For neutron, SS-316 was found to be the best shielding materials in energy 2-12 MeV. This study should be useful for potential applications of these materials in nuclear reactor core design and other industries for choice of effective gamma ray and neutron shielding materials. © 2013 Elsevier Ltd. All rights reserved.

Nagella P.,Karnatak University | Murthy H.N.,Karnatak University
Bioresource Technology | Year: 2010

Cell suspension cultures of Withania somnifera were established in shake flasks and the effect of different growth regulators (auxins, combination of auxin and cytokinin), inoculum density (2.5-20 g L-1), different media (MS, B5, NN and N6), the strength of the MS medium (0.25-2.0×), carbon source (sucrose, glucose, fructose, maltose), concentration of the sucrose (1-8% (w/v)) and the initial pH (4.0-6.5) of the medium were determined for the production of withanolide A. The optimized conditions for biomass accumulation and withanolide A production were found to be 10 g L-1 of the inoculum on fresh weight basis, the full strength MS medium, 3% (w/v) sucrose, four weeks culture period and the initial medium pH of 5.8. The results of present study are useful for scale-up process. © 2010 Elsevier Ltd. All rights reserved.

Nagella P.,Karnatak University | Murthy H.N.,Karnatak University
Plant Cell, Tissue and Organ Culture | Year: 2011

Withania somnifera is an important medicinal plant that contains withanolides and withaferins, both bioactive compounds. We have tested the effects of macroelements and nitrogen source in W. somnifera cell suspension cultures with the aim of optimizing the production of biomass and withanolide A. The effects of the macroelements NH4NO3, KNO3, CaCl2, MgSO4 and KH2PO4 at concentrations of 0.0, 0.5, 1.0, 1.5 and 2.0× strength and of the nitrogen source [NH4 +/NO3 - (mM/mM) ratio of: 0.00/18.80, 7.19/18.80, 14.38/18.80, 21.57/18.80, 28.75/18.80, 14.38/0.00, 14.38/9.40, 14.38/18.80, 14.38/28.20, and 14.38/37.60 (mM)] in Murashige and Skoog medium were tested for biomass and withanolide A production. The highest accumulation of biomass [147.81 g l-1 fresh weight (FW) and 14.02 g l-1 (dry weight (DW)] was recorded in the medium containing a 0.5× concentration of NH4NO3, and the highest production of withanolide A content was recorded in the medium with 2.0× KNO3 (4.36 mg g-1 DW). The NH4 +/NO3 - ratio also influenced cell growth and withanolide A production, with both parameters being larger when the NO3 - concentration was higher than that of NH4 +. Maximum biomass growth (110.45 g l-1 FW and 9.29 g l-1 DW) was achieved at an NH4 +/NO3 - ratio of 7.19/18.80, while withanolide A production was greatest (3.96 mg g-1 DW) when the NH4 +/NO3 - ratio was 14.38/37.60 mM. © 2010 Springer Science+Business Media B.V.

Singh V.P.,Karnatak University | Badiger N.M.,Karnatak University
Journal of Radiological Protection | Year: 2014

A comprehensive study of gamma-ray exposure build-up factors (EBFs) of fly-ash brick materials has been carried out for photon energies of 0.015-15 MeV up to a penetration depth of 40 mfp (mean free path) by a geometrical progression (GP) fitting method. The EBF values of the fly-ash brick materials were found to be dependent upon the photon energy, penetration depth and chemical composition, and were found to be higher than the values for mud bricks and common bricks. Above a photon energy of 3 MeV for large penetration depths (>10 mfp), the EBF becomes directly proportional to Zeq. EBFs of fly-ashes were found to be less than or equal to those of concrete for low penetration depths (<10 mfp) for intermediate photon energies up to 1.5 MeV. The EBF values of fly-ash materials were found to be almost independent of Si concentration. The fast neutron removal cross sections of the fly-ash brick materials, mud bricks and common bricks were also calculated to understand their shielding effectiveness. The shielding effectiveness of the fly-ash materials against gamma-ray radiation was lower than that of common and mud bricks. © 2014 IOP Publishing Ltd.

Nissimagoudar A.S.,Karnatak University | Sankeshwar N.S.,Karnatak University
Carbon | Year: 2013

A theoretical investigation of the diffusion contribution to thermopower, Sd, and the electronic thermal conductivity, κe, of semiconducting armchair graphene nanoribbons (GNRs) is made for T ≤ 300 K. Considering the electrons to be scattered by edge roughness, impurities and deformation-potential coupled acoustic phonons and optical phonons, expressions for Sd and κe are obtained. Numerical calculations of Sd and κe, as functions of temperature and linear carrier density, bring out the relative importance of the contributing scattering mechanisms. A GNR of width 5 nm, supporting an electron density 2 × 108 m-1, is found to exhibit room temperature values of Sd and κe as 42 μV/K and 26.5 W/mK, respectively. A decrease in armchair GNR width, is found to enhance S d and reduce κe. The effect of varying the electron density is to increase their magnitude when Fermi energy moves into the second subband. An analysis of thermopower and thermal conductivity data in clean armchair GNR samples will enable better understanding of the electron-phonon interaction. © 2012 Elsevier Ltd. All rights reserved.

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