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71.
The conducting and relaxation dynamics of Ag+ ions in poly(ethylene oxide) (PEO)–silver triflate (AgCF3SO3) solid polymer electrolytes (SPEs) containing nanosize SiO2 filler and poly(ethylene glycol) (PEG) as a plasticizer were studied in the frequency range 10 Hz to 10 MHz and in the temperature range 303–328 K. The comparatively lower conductivity of the plasticized (PEG) PEO–AgCF3SO3–SiO2 nanocomposite electrolyte system was examined by analysis of the Fourier transform infrared (FTIR) spectroscopy and conductivity data. The electric modulus (M″) properties of the SPE systems were investigated. A shift of the M″ peak spectra with frequency was found to depend on the translation ion dynamics and the conductivity relaxation of the mobile ions. The value of the conductivity relaxation time was observed to be lower for the PEO–AgCF3SO3 system only with nanofiller SiO2. The scaling behavior of the M″ spectra showed that the dynamical relaxation processes was temperature-independent in the PEO–AgCF3SO3 and PEO–AgCF3SO3–SiO2–PEG polymer systems, whereas they were temperature-dependent for the PEO–AgCF3SO3–SiO2 system. However, the relaxation processes of all of theses systems were found to be dependent on their respective compositions. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
72.
Poonam Rani Rajveer Jha V. P. S. Awana 《Journal of Superconductivity and Novel Magnetism》2013,26(7):2347-2352
We report the effect of silver addition on superconducting performance of bulk YBCO (YBa2Cu3O7) superconductor. All the studied samples are prepared by conventional solid-state reaction method. Rietveld fitted X-ray diffraction data confirmed the single phase formation for all the studied samples. Detailed AC susceptibility measurements as a function of driven AC amplitude (1 Oe–17 Oe) of these samples revealed the enhancement of grains coupling with increasing Ag content in YBCO + Ag x composite system. 10 wt% Ag added YBCO superconductors exhibited the optimal intergranular coupling. The Scanning Electron Microscopy (SEM) observations indicate an increase in the grains connectivity in terms of narrow grain boundaries for doped samples. The average grain size is found to increase with Ag doping. It is concluded that limited addition of Ag in bulk YBCO superconductor significantly improves the grains coupling and, as a result, the optimal superconducting performance. YBCO + Ag composites could prove to be potential candidates for bulk superconducting applications of the studied high-T c system. 相似文献
73.
Abdullah I. Hussain Farooq Anwar Poonam S. Nigam Satyajit D. Sarker Juluri R. Rao Anisha Mazumdar 《LWT》2011,44(4):1199-1206
The aim of this work was to investigate the antibacterial activity of six Lamiaceae essential oils, against pathogenic and food spoilage bacteria. The chemical profiles of essential oils were evaluated by the means of GC and GC-MS. The major constituents of the oils were 1,8-cineol (29.2%), camphor (17.2%), α-pinene (11.5%) in Rosmarinus officinalis, citronellal (20.5%), β- geraniol (17.0%), β-citronellol (11.5%) in Melissa officinalis, 1,8-cineol (27.4%), α-thujone (16.3%), β-thujone (11.2%), borneol (10.4%), camphor (7.98%) in Salvia officinalis, linalool (25.1%), linalyl acetate (22.5%) in Lavandula angustifolia, thymol (52.4%), p-cymene (17.9%) in Thymus vulgaris and Patcholene alcohol (22.7%), α-bulnesene (17.1%), α-guaine (13.8%) in Pogostemon cablin. On quantitative basis, the amounts of 1,8-cineol, citronellal, 1,8-cineol, linalool, thymol and patchouli alcohol, calculated using calibrated curve with pure standard compounds, in the respective essential oils were found to be 28.4, 19.0, 26.7, 23.3, 51.1 and 21.1 g/100 g of oil, respectively. The modified resazurin microtitre-plate assay was used to evaluate the antibacterial activity of the essential oils and their principal components. All the essential oils analyzed presented inhibitory effects on most of the strains tested. Thymus vulgaris essential oil showed the highest inhibition. It was concluded that modified resazurin assay could be effectively used for reliable assessment of antibacterial activity of the tested essential oils against several Gram positive and negative bacterial taxa. The present results also demonstrated that Lamiaceae essential oils exhibiting higher antibacterial activity were generally rich in oxygenated monoterpens. 相似文献
74.
Poonam Singhal Geetanjali Kaushik 《Critical reviews in food science and nutrition》2016,56(5):748-759
Over the last few decades, life style changes have resulted in drastic increase in the incidence of diabetes all over the world, especially in the developing countries. Oral hypoglycemic agents and insulin form the main stay in controlling diabetes but they have prominent side effects and fail to significantly alter the course of diabetic complications. Appropriate diet and exercise programs that form a part of lifestyle modifications have proven to be greatly effective in the management of this disease. Dietary therapy is showing a bright future in the prevention and treatment of diabetes. Cereal grains which form the staple diet for humans in most of the countries are increasingly being used to treat diabetes and other associated disorders in view of their anti-diabetic and anti-lipidemic potential. Given this background, this paper reviews the possible mechanisms of lowering blood sugar and cholesterol levels possessed by various commonly consumed cereal grains. It is concluded that cereal grains are not only the potential sources of energy but also possess the therapeutic role in preventing metabolic disorders and decreasing the risk factors for cardiovascular and renal diseases. 相似文献
75.
Poonam Bandyopadhyay Anindita Dey Ruma Basu Papiya Nandy 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(13):1833-1839
The synthesis, characterization, and application of engineered nanomaterials in different fields have opened up new aspects of nanotechnology. Using a simple chemical method, this study describes the synthesis of highly dispersed Cu-doped ZnO nanoparticles with different concentrations of Cu (1, 3, and 5 mM). The nanoparticles thus synthesized were tested for their effect on photo-induced voltage generation, enhancement of storage capacity, and energy conversion efficiency in hybrid photoelectrochemical (PEC) cell. Maximum photovoltage (~680 mV) with highest storage capacity (~53 h) and high energy conversion efficiency (~2.16%) was generated using these nanoparticles when the doping concentration of Cu was 3 mM. 相似文献
76.
Shah M Karekar P Sancheti P Vyas V Pore Y 《Drug development and industrial pharmacy》2009,35(1):118-129
The effect of polyvinyl pyrrolidone (PVP) K30 and/or L-arginine on etoricoxib-HPbetaCD complex was investigated. The phase solubility profiles were classified as A(L)-type, both in absence or presence of auxiliary substances used. The apparent stability constant (K(c)) of binary complex obtained at room temperature, 371.80 +/- 2.61 M(-1), was decreased with the addition of PVP and arginine indicating no benefit of addition of auxiliary substances to promote higher complexation efficiency. Therefore, solid etoricoxib-HPbetaCD binary systems were prepared and characterized by proton nuclear magnetic resonance spectroscopy (1HNMR), X-ray powder diffractometry, Fourier transformation-infrared spectroscopy, and dissolution studies. Among all binary systems, a lyophilized product showed superior performance in enhancing dissolution of etoricoxib. 相似文献
77.
78.
79.
Abdullah I Hussain Farooq Anwar Poonam S Nigam Muhammad Ashraf Anwarul H Gilani 《Journal of the science of food and agriculture》2010,90(11):1827-1836
BACKGROUND: The aim of the present study was to appraise variation in the chemical composition, and antimicrobial and cytotoxic activities of essential oils from the leaves of four Mentha species—M. arvensis, M. piperita, M. longifolia and M. spicata—as affected by harvesting season. Disc diffusion and broth microdilution susceptibility assays were used to evaluate the antimicrobial activity of Mentha essential oils against a panel of microorganisms. The cytotoxicity of essential oils was tested on breast cancer (MCF‐7) and prostate cancer (LNCaP) cell lines using the MTT assay. RESULTS: The essential oil contents of M. arvensis, M. piperita, M. longifolia and M. spicata were 17.0, 12.2, 10.8 and 12.0 g kg?1 from the summer and 9.20, 10.5, 7.00 and 9.50 g kg?1 from the winter crops, respectively. Gas chromatographic–mass spectrometric analysis revealed that mostly quantitative rather than qualitative variation was observed in the oil composition of each species. The principal chemical constituents determined in M. arvensis, M. piperita, M. longifolia and M. spicata essential oils from both seasons were menthol, menthone, piperitenone oxide and carvone, respectively. The tested essential oils and their major components exhibited notable antimicrobial activity against most of the plant and human pathogens tested. The tested essential oils also exhibited good cytotoxicity potential. CONCLUSION: Of the Mentha essential oils tested, M. arvensis essential oil showed relatively better antimicrobial and cytotoxic activities. A significant variation in the content of most of the chemical components and biological activities of seasonally collected samples was documented. Copyright © 2010 Society of Chemical Industry 相似文献
80.
This paper reports the effect of nanofiller concentration on the conductivity and dielectric properties of the poly(ethylene oxide)–poly(methyl methacrylate)–poly(ethylene glycol)–AgNO3–Al2O3 polymer electrolyte system. The preparation of polymer films was done using the solution‐casting technique and characterization of the films was carried out using scanning electron microscopy, differential scanning calorimetry and ionic transport techniques. The ionic conductivity, investigated using impedance spectroscopy, was expected to show interesting behaviour at below and above the melting temperature of poly(ethylene oxide) in the polymer blend films. Complex impedance data were analysed in an alternating current conductivity and dielectric permittivity formalism in order to throw light on the transport mechanism. The effect of nanofiller concentration on conduction and relaxation processes at various temperatures was studied. © 2013 Society of Chemical Industry 相似文献