Chaudhuri T.K.,Gujarat University |
Tiwari D.,Gujarat University
Solar Energy Materials and Solar Cells | Year: 2012
A simple process for deposition of pure CZTS films from a methanolic solution of metal-thiourea complex is described. The precursor films are thermolysed at 200 °C in air for 10 min. Formation of kesterite CZTS is confirmed by X-ray diffraction (XRD). The films have grains of 100-200 nm and rms roughness of 1-2 nm. The energy band gap of CZTS films is 1.4 eV and is p-type in nature with electrical conductivity of 0.5 S/cm and thermo electric power coefficient of 86 μV/K. The films are photoconducting. © 2012 Elsevier B.V. All rights reserved.
Kharadi G.J.,Gujarat University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013
New Fe(III) complexes have been synthesized by the reactions of ferric nitrate with Schiff base derived from 3-substituted phenyl-4-amino-5-hydrazino- 1,2,4-triazole and indoline-2,3-dione. All these complexes are soluble in DMF and DMSO; low molar conductance values indicate that they are non-electrolytes. Elemental analyses suggest that the complexes have 1:1 stoichiometry of the type [FeLn(H2O)(OH)]xH2O. Structural and spectroscopic properties have been studied on the basis of elemental analyses, infrared spectra, 1H and 13H NMR spectra, electronic spectra, magnetic measurements and FAB mass spectra. FT-IR, 1H and 13H NMR studies reveal that the ligand (Ln) exists in the tautomeric enol form in both the states with intramolecular hydrogen bonding. Magnetic moment and reflectance spectral studies reveal that an octahedral geometry has been assigned to all the prepared complexes. FRAP values indicate that all the compounds have a ferric reducing antioxidant power. The compounds 2 and 3 showed relatively high antioxidant activity while compound 1 and 4 shows poor antioxidant power. Also good antimicrobial activities of the complexes against Staphylococcus aureus, Bacillus subtilis, Serratia marcescens, Pseudomonas aeruginosa and Escherichia coli have been found compared to its free ligands. © 2013 Elsevier B.V. All rights reserved.
Kharadi G.J.,Gujarat University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014
An octahedral complexes of copper with clioquinol(CQ) and substituted terpyridine have been synthesized. The Cu(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation. Ferric-reducing anti-oxidant power of all complexes were measured. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity. © 2013 Elsevier B.V. All rights reserved.
Makadia A.J.,Gujarat University |
Nanavati J.I.,Gujarat University
Measurement: Journal of the International Measurement Confederation | Year: 2013
Design of experiments has been used to study the effect of the main turning parameters such as feed rate, tool nose radius, cutting speed and depth of cut on the surface roughness of AISI 410 steel. A mathematical prediction model of the surface roughness has been developed in terms of above parameters. The effect of these parameters on the surface roughness has been investigated by using Response Surface Methodology (RSM). Response surface contours were constructed for determining the optimum conditions for a required surface roughness. The developed prediction equation shows that the feed rate is the main factor followed by tool nose radius influences the surface roughness. The surface roughness was found to increase with the increase in the feed and it decreased with increase in the tool nose radius. The verification experiment is carried out to check the validity of the developed model that predicted surface roughness within 6% error.
Kumar S.P.,Gujarat University
Omics : a journal of integrative biology | Year: 2013
It is a continuing quest to uncover the principal molecular targets of malarial parasites to understand the antimalarial activity and mechanism of action of artemisinin, a potent antimalarial. A series of parasite proteins are experimentally validated as potential targets, such as translationally controlled tumor protein (TCTP) and sarco/endoplasmic reticulum membrane calcium ATP-ase (SERCA). The present study addressed the development of a theoretical model of Plasmodium falciparum NADH dehydrogenase with inference from artemisinin in vivo inhibitory activity. We report here the predicted binding modes of artemisinin and its derivatives. The modeled protein resembled the structural architecture of flavoproteins and oxidoreductases, consisting of two Rossmann folds and dedicated binding sites for its cofactors. Docked poses of the ligand dataset revealed its interactions at or near the si face, indicating being activated. This may aid in generation of reactive oxygen species, thereby disrupting the membrane potential of parasite mitochondria and leading to the clearance from the blood. These observations open up new strategies for development of novel therapeutics, or improvement of existing pharmacotherapies against malaria, a major burden for global health.
Jadeja R.N.,Gujarat University
Asian Pacific journal of tropical medicine | Year: 2012
Present review for the first time provides a complete botanical description and information on ethnomedicinal uses of Clerodendron glandulosum.Coleb (CG; Fam, Verbenaceae). Recent studies conducted from our laboratory provide pharmacological evidence for its anti-hypertensive, anti-diabetic and anti-obesity potentials. Further, its beneficial potential in preventing in vitro and in vivo non-alcoholic steatohepatitis and atherosclerosis and potent hepatoprotective and free radical scavenging abilities along with its acute and sub-chronic toxicological evaluations are also reported from our laboratory. In keeping with its traditional uses, CG extract was capable of ameliorating experimentally induced hypertension, diabetes and obesity. Its beneficial potential against NASH induced oxidative stress and atherosclerosis can be attributed to its potent free radical scavenging potential. Non-toxic nature of CG leaf extract further provides added merit to its reported pharmacological properties. The present review summarizes the pioneering scientific evidence for the pharmacological effects of CG against related metabolic disorders like hypertension, diabetes and obesity along with anti oxidant potential and beneficial effects against non alcoholic steatohepatitis. Copyright © 2012 Hainan Medical College. Published by Elsevier B.V. All rights reserved.
Shah D.,Gujarat University |
Kaur H.,Gujarat University
Journal of Molecular Catalysis A: Chemical | Year: 2014
Gold in nanoparticle form shows good catalytic activity in contrast to bulk form and is finding applications in a variety of organic reactions. The present investigation describes direct deposition of gold nanoparticles onto commercially available resin by sorption reduction method. Uniformly dispersed nanoparticles of 3-8 nm dimensions were characterized by UV-visible spectroscopy, XRD, SEM and TEM, etc. The AuNPs were found to be remarkably stable and active catalysts for the selective reduction of nitro group under mild reaction conditions and microwave-assisted ligand-free Suzuki-Miyaura cross-coupling reaction between aryl halides and phenylboronic acid. Calculated rate constant (2.5 × 10-2 s-1) for the reduction of 4-nitrophenol is among the best reported in the literature. The versatility of both the protocols is demonstrated by taking a number of substrates. © 2013 Elsevier B.V. All rights reserved.
Pandya A.,Gujarat University
The Analyst | Year: 2013
We developed a new, advanced, simple and non enzymatic approach for the colorimetric detection of glucose based on calixarene/phenyl boronic acid (CX-PBA)functionalized gold nanoparticles (AuNPs). This molecular receptor proficiently and selectively recognizes glucose due to its ability to reversibly bind diol-containing compounds. The assembly was characterized by transmission electron micrograph (TEM), dynamic light scattering (DLS), UV-Vis, FT-IR, ESI-MS and (1)H NMR spectrometry, which demonstrates the binding affinity for glucose via a boronic acid-diol interaction. The linear range for glucose was found to be 5-100 nM with phosphate buffer pH 10, with a lower detection limit of 4.3 nM. Interference by other saccharides was negligible. The biosensor has been successfully applied to estimate the glucose in human blood serum samples and the results compared well to an automatic analyzer. With the advantages of high sensitivity, selectivity and low sample volume, this method is potentially suitable for the on-site monitoring of glucose.
Vala A.K.,Gujarat University
Bioresource Technology | Year: 2010
The objective of the work was to investigate tolerance to and removal of arsenic by a facultative marine fungus Aspergillus candidus. The fungus showed luxuriant growth in different concentrations (25 and 50 mg/L) of trivalent and pentavalent forms of arsenic. Biomass accumulation data substantiate tolerance of A. candidus towards the test concentrations of trivalent and pentavalent forms of arsenic. Highest arsenic removal (mg/g) was recorded on day 3. As removal increased with an increase in concentration. Hence, the test fungus A. candidus is a promising candidate for arsenic remediation. © 2009 Elsevier Ltd. All rights reserved.
Patel R.,Gujarat University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012
The simultaneous effect of magnetic field and temperature on the capillary viscosity of magnetic nanofluid is an important parameter for a new class of applications such as nanoduct flow, nanomotors, micro- and nanofluidic devices, for transformer cooling, magnetic targeted drug delivery, etc. The effective viscosity of a nanofluid is explained based on the rotation of the particles and the effect of torque on it due to an externally applied magnetic field. Two types of fluids are used here, temperature-sensitive and non-temperature- sensitive magnetic nanofluids. In both types of fluids, decrease in effective viscosity with temperature is observed, but in both cases the mechanism for the decrement is quite different. One is due to temperature dependence of the magnetic moment and the other is due to removal of the secondary surfactant. For temperature-sensitive magnetic nanofluids, a Curie temperature of ∼80 C is extracted from this study. For non-temperature-sensitive magnetic nanofluids ∼65% of the secondary surfactant is removed for a change in temperature, ΔT = 40 C. This is analogous with removal of a drug from magnetic particles for targeted drug delivery. Further, a linear dependence of effective viscosity with different capillary size and ξ (angle between magnetic field and flow direction, ξ[0,π/2]) is also observed. This linear dependence can also be a good approximation for the study of magnetic drug targeting, as in the human body the capillaries are of different sizes, and the externally applied magnetic field is not always parallel or perpendicular to the drug flow direction. © 2012 American Physical Society.