Time filter

Source Type

Dharwad, India

Herein we report the successful fabrication of highly flexible, reversibly stretchable, transparent, and conductive poly(vinyl alcohol) (PVA) nanocomposite (NC) films with a hydrophobic surface by reinforcing varying amounts, viz., 0, 0.5, 1, 2, and 4 wt %, of calcium zincate (Ca0.2Zn0.8O) nanofillers. The developed nanocomposite films show appreciable UVA screening efficacies as established by a novel (UV-transillumination studies) method. The Fourier transform infrared (FTIR) studies reveal a positive interaction between PVA matrix and incorporated nanofiller, while scanning electron microscopic (SEM) studies support uniform filler dispersions. The electronic spectral studies substantiate the changes in electronic band structure of composite films leading to appreciable changes in the optoelectronic properties. The fluorescent emission studies reveal dopant-dependent photonic emissions, while the dielectric properties, such as dielectric constant (ϵ') and dielectric loss (ϵ''), increase with an increase in filler volumes up to an optimal filler fraction (2 wt % of Ca0.2Zn0.8O) owing to the segmental motion of polymer chains in addition to interfacial polarization associated with multicomponent systems. The developed films with excellent optoelectronic properties alongside appreciable flexibilities and stretchabilities aid their applications as multifunctional UVA shielding polymeric composites with enhanced photoconductivities. © 2016 American Chemical Society. Source

Shivamallu C.,University of Mysore | Sharanaiah U.,University of Mysore | Kollur S.P.,Jss College | Mallesh N.K.R.,University of Mysore | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

In this paper, we describe the synthesis of novel class of pseudo-peptides derived by coupling an amino acid with a heterocyclic moiety containing free amine group using suitable coupling agents. The synthesized compounds were characterized using spectral (1H NMR, 13C NMR and MS) techniques. Preliminary pharmacological assays for Leptospirosis were studied by test tube dilution (TDT) and micro dilution technique (MDT). In particular, all the analyses led to the conclusion that the synthesized compound inhibiting the Leptospira a causal organism of Leptospirosis. © 2013 Elsevier B.V. All rights reserved. Source

Patil P.B.,Karnatak University | Kallapur S.V.,Jss College | Kallapur V.L.,Karnatak University | Holihosur S.N.,Karnatak University
Asian Pacific Journal of Tropical Disease | Year: 2014

Objective: To investigate insecticidal properties of organic solvent extracts of Clerodendron inerme (C. inerme) leaves against larval stages of Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus) mosquito species. Methods: The sundried leaf powder of C. inerme was subjected for extraction using organic solvents viz. methanol, chloroform, petroleum ether and hexane extract, and were tested against third/fourth instar larvae of Ae. aegypti and Cx. quinquefasciatus species in accordance with WHO standard methods. Experiments were conducted in four replicates with control group containing water alone and positive control group containing respective solvent (dimethylsulfoxide/acetone) used for dissolving the extracts. Results: Among the four solvent extracts, hexane extract has effective growth disruptive activity against Ae. aegypti, and showed positive tests for presence of four groups of phytochemical constituents viz. tanin, phytosteriod, terpenoid and cardiac glycoside. The hexane extract was tested against field collected filarial vector Cx. quinquefasciatus larvae for growth disruptive activity. Adult emergence inhibition values for 50 percent suppression (EI50) of the tested population for methanol, chloroform, petroleum ether and hexane extracts treated against third instar larvae of Ae. aegypti were found to be 37.45, 14.79, 2.56 and 1.96 mg/L respectively, while hexane extract treated against Cx. quinquefasciatus was found to be equally effective with EI50 value of 3.74 mg/L. Hexane extract treated against fourth instar larvae of Ae. aegypti and Cx. quinquefasciatus showed EI50 values of 8.07 and 19.55 mg/L respectively in comparison with that of standard insect growth regulator methoprene demonstrating EI50 value of 0.05 mg/L. Besides, the hexane extract was also found to possess toxic effect against non-target organism Gambusia affinis (a bio-control agent), however, the lethal concentration (LC50=172.7 mg/L for 24 h) against Gambusia affinis was much higher in comparison with that of tested concentrations against Ae. aegypti and Cx. quinquefasciatus. Conclusions: We conclude from the present investigation that the hexane extract of C. inerme has positive implications for its consideration in integrated control of dengue/filarial vectors due to their ecological distinctness in comparison with non-target organism and further due to ecofriendly nature of the extract in terms of easy biodegradability. © 2014 Asian Pacific Tropical Medicine Press. Source

Patil S.K.,Jss College | Wari M.N.,Karnatak University | Inamdar S.R.,Karnatak University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

The absorption and fluorescence spectra of three medium sized dipolar laser dyes: coumarin 478 (C478), coumarin 519 (C519) and coumarin 523 (C523) have been recorded and studied comprehensively in various solvents at room temperature. The absorption and fluorescence spectra of C478, C519 and C523 show a bathochromic and hypsochromic shifts with increasing solvent polarity indicate that the transitions involved are π → π â̂ - and n → πâ̂ -. Onsager radii determined from ab initio calculations were used in the determination of dipole moments. The ground and excited state dipole moments were evaluated by using solvatochromic correlations. It is observed that the dipole moment values of excited states (μe) are higher than corresponding ground state values (μg) for the solvents studied. The ground and excited state dipole moments of these probes computed from ab initio calculations and those determined experimentally are compared and the results are discussed. © 2013 Elsevier B.V. All rights reserved. Source

Rajendraprasad N.,Jss College | Basavaiah K.,University of Mysore
Journal of Applied Spectroscopy | Year: 2014

Two simple, accurate and precise spectrophotometric methods are developed and validated for the assay of pyrantel pamoate (PP) in pharmaceuticals. The methods employ the oxidative property of potassium permanganate (KMnO4) in acidic and alkaline conditions. In the first method (method A), PP is converted into its free base, pyrantel (PR), and treated with known excess of KMnO4 in acidic condition followed by the measurement of unreacted KMnO4 at 550 nm. Method B is based on the registration of absorbance of green colored chromogen formed due to the reduction of KMnO4 by PP in alkaline condition. The methods obeyed Beer's law over a range of 1-20 μg/ml in inverse manner, and 0.75-15 μg/ml for method A and method B, respectively, with apparent molar absorptivity values of 1.05{dot operator}104 and 2.85{dot operator}104 l{dot operator}mol-1{dot operator}cm-1. The optical parameters such as limits of detection (LOD), quantification (LOQ), and the Sandell sensitivity values are also reported. The accuracy and precision of the methods are assessed on intra- and inter-day basis. A recovery study by standard addition procedure is also carried out for further assurance of accuracy. The developed methods are successfully applied to determine PP in tablets. The results are more satisfactory as per current ICH guidelines. © 2014 Springer Science+Business Media New York. Source

Discover hidden collaborations