Bharathiar University

About: Bharathiar University is a education organization based out in Coimbatore, Tamil Nadu, India. It is known for research contribution in the topics: Thin film & Adsorption. The organization has 5812 authors who have published 8628 publications receiving 143934 citations. The organization is also known as: BU.

Biolarvicidal and pupicidal potential of silver nanoparticles synthesized using Euphorbia hirta against Anopheles stephensi Liston (Diptera: Culicidae).

Abstract: Vector control is a critical requirement in epidemic disease situations, as is an urgent need to develop new and improved mosquito control methods that are economical and effective yet safe for nontarget organisms and the environment. Mosquitoes transmit serious human diseases, causing millions of deaths every year. Use of synthetic insecticides to control vector mosquitoes has caused physiological resistance and adverse environmental effects in addition to high operational cost. Insecticides of synthesized natural products for vector control have been a priority in this area. In the present study, activity of silver nanoparticles (AgNPs) synthesized using Euphorbia hirta (E. hirta) plant leaf extract against malarial vector Anopheles stephensi (A. stephensi) was determined. Range of concentrations of synthesized AgNPs (3.125, 6.25, 12.5, 25, and 50 ppm) and methanol crude extract (50, 100, 150, 200, and 250 ppm) were tested against larvae of A. stephensi. The synthesized AgNPs from E. hirta were highly toxic than methanolic crude extract against malarial vector, A. stephensi. The synthesized AgNPs were characterized by UV-vis spectrum, scanning electron microscopy (SEM), and X-ray diffraction. SEM analyses of the synthesized showed that AgNPs, measuring 30-60 nm in size, were clearly distinguishable. The synthesized AgNPs showed larvicidal effects after 24 h of exposure; however, the highest larval mortality was found in the synthesized AgNPs against the first to fourth instar larvae and pupae of values LC(50) (10.14, 16.82, 21.51, and 27.89 ppm, respectively), LC(90) (31.98, 50.38, 60.09, and 69.94 ppm, respectively), and the LC(50) and LC(90) values of pupae of 34.52 and 79.76 ppm, respectively. Methanol extract exhibited the larval toxicity against the first to fourth instar larvae and pupae of values LC(50) (121.51, 145.40, 169.11, and 197.40 ppm, respectively), LC(90) (236.44, 293.75, 331.42, and 371.34 ppm, respectively), and the LC(50) and LC(90) values of pupae of 219.15 and 396.70 ppm, respectively. No mortality was observed in the control. These results suggest that synthesized silver nanoparticles are a rapid, eco-friendly, and single-step approach; the AgNPs formed can be potential mosquito larvicidal agents.

Redox additive aqueous polymer gel electrolyte for an electric double layer capacitor

Abstract: A hydroquinone mediated PVA–H2SO4 gel electrolyte (PHHQ) and activated carbon from bio-waste were prepared for supercapacitor fabrication. PHHQ delivered a higher capacitance (941 F g−1 at 1 mA cm−2) and energy density (20 Wh kg−1 at 0.33 W g−1) than the PVA–H2SO4 gel electrolyte (425 F g−1 at 1 mA cm−2, 9 Wh kg−1 at 0.33 W g−1).

Green algae Chlorococcum humicola- a new source of bioactive compounds with antimicrobial activity

Abstract: Objective To analyse the existence of bioactive phytochemicals and their antimicrobial role of green algae Chlorococcum humicola (C. humicola). Methods The various organic solvents such as acetone, benzene, chloroform, diethyl ether, ethyl acetate, ethanol, hexane and methanol were used for the preparation of the algal extracts then subjected to chemical analysis and further used for the screening of antimicrobial assay. The purified carotenoid pigments and chlorophylls were used for the antimicrobial studies against the harmful pathogens Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, Vibreo cholerae, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Aspergillus niger and Aspergillus flavus. Results The chemical analysis showed the existence of bioactive compounds such as carotenoids, alkaloids, favanoids, fattyacids, saponins, aminoacids and carbohydrates. In vitro screening of organic solvent extracts of green algae C. humicola shows activity in inhibiting the growth of virulent strains of bacteria and fungi pathogenic to human. Eight different extracts showed effective inhibitory action against the selected pathogens. Depends upon their existence of the bioactive compounds the different organic algal extracts shows difference in their inhibitory zone against the microbes. Out of all the organic extracts benzene and ethyl acetate extracts showed excellent effect nearly 80% microbial growth inhibition. The separated carotenoid and chlorophyll fractions of C. humicola, also results in the microbial growth inhibition. Conclusions The present study concludes that green algae C. humicola are a rich and varied source of pharmacologically active natural products and nutraceuticals. While nutraceutical and pharmaceutical content in the baseline algae strain is very small, they showed excellent effect against the microbial pathogens.

Properties of titanium nitride films prepared by direct current magnetron sputtering

Abstract: Titanium nitride (TiN) thin films of different thickness were deposited by direct current (dc) magnetron sputtering under conditions of various N2 concentrations (05–34%) The electrical, optical, structural, compositional and morphological properties of the films were studied and the results were discussed with respect to N2 concentration and thickness of the films At low N2 concentration of 05% (of the total sputtering pressure 11 Pa), golden coloured stoichiometric TiN films were obtained and with increase in the N2 concentration non-stoichiometric TiNx phases resulted However, irrespective of the N2 concentration, the TiN stoichiometry in the films increased with increase in the film thickness In the surface of the films the presence of nitride (TiN), oxynitride (TiOxNy) and oxide (TiO2) phases were observed and the quantity of these phases varied with the N2 concentration and thickness The films of lower thickness were found to be amorphous and the crystallinity was observed in the films with increase in the thickness The crystalline films showed reflections corresponding to the (1 1 1), (2 0 0) and (2 2 0) orientation of the cubic TiN and also features associated with TiNx phases The transmission spectra of the films revealed the typical characteristics of the TiN films ie a narrow transmission band, however, the width varied with thickness, in the wavelength range of 300–600 nm and exhibited low transmission in the infrared region The TiN films deposited at low N2 concentration of 05% showed smooth and uniform morphology with densely packed crystallites With increase in N2 concentration various characteristics such as needle type crystallization, bubble precipitates and after bubble burst morphologies were observed in the films However, at higher N2 concentration conditions, uniformity developed in the films with increase in thickness