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Bursal E.,Mus Alparslan University | Gulcin I.,Ataturk University | Gulcin I.,Agrl Ibrahim Cecen University
Food Research International | Year: 2011

The aim of this study was to determine the antioxidant potency and total phenolic and flavonoid contents of kiwifruit (Actinidia deliciosa) in vitro by analysing the radical scavenging activity of lyophilised water extract from kiwifruit (LEK) for 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl-hydrazyl (DPPH), N,N-dimethyl-p-phenylenediamine (DMPD), and superoxide anion radical (O2 -) as well as the total reducing power by FRAP and CUPRAC assays and the metal chelating activities. LEK showed efficient radical scavenging activity with DPPH, ABTS, DMPD, and O2 - radicals; ferric (Fe3+) and cupric (Cu2+) ion reducing power and metal chelating activities. Moreover, the amounts of phenolic compounds, such as caffeic acid, ferulic acid, syringic acid, ellagic acid, catechol, pyrogallol, p-hydroxy benzoic acid, vanillin, p-coumaric acid, gallic acid, quercetin, α-tocopherol and ascorbic acid, in LEK were quantified by LC-MS-MS. The results show that pyrogallol (2070.0mg/kg LEK) is the main phenolic compound responsible for the antioxidant and radical scavenging activities of LEK. Finally, total phenolic and flavonoid contents were determined as gallic acid (GAE) and quercetin equivalents (QE). The GAE and QE values in LEK were 16.67±2.83μg GAE/mg and 12.95±0.52μg QE/mg, respectively. The results suggest that consumption of kiwifruit (A. deliciosa) can be beneficial effects due to its antioxidant properties. © 2011 Elsevier Ltd. Source

Bursal E.,Mus Alparslan University | Koksal E.,Erzincan University
Food Research International | Year: 2011

The purpose of this study was to determine the reducing power, metal chelating, and radical scavenging capabilities of water and ethanol extracts of sumac (Rhus coriaria L.), comparatively. The water and ethanol extracts of sumac were evaluated for their radical scavenging activities by means of the DPPH and DMPD assays. Water extract of sumac (R. coriaria L.) scavenged radicals effectively with EC50 values of 36.4μg/ml for DPPH free radical and 44.7μg/ml for DMPD cation radical. Similarly, the total reducing power of water extract was found higher than ethanol extract in both potassium ferricyanide reduction (FRAP) and cupric ions reduction capacity methods (CUPRAC). 2,2'-Bipyridine was used to determine the metal chelating activity and the result of water extract was found higher than ethanol extract. Total phenolic and total flavonoid contents of both extracts were studied as well. The values of water extract were found to be higher than that of ethanol extract. The present study found that water extracts of sumac (R. coriaria L.) have effective antioxidant and radical scavenging activities as compared to ethanol extracts. © 2010 Elsevier Ltd. Source

TIPS-pentacene transistors were fabricated using thermal evaporation technique with different thicknesses of the active layer (TIPS-pentacene) and various channel widths deposited on SiO 2 layer and compared the performance and photo characteristics of TIPS-pentacene (300 nm) and (135 nm) transistors. In present review, we report the photoresponse performance of the pentacene thin-film transistors including various channel widths and active layer thickness. The performance and photo characteristics of the TIPS-pentacene (300 nm) and (135 nm) transistors were investigated under dark and white light illuminations and analyzed the effects of the channel widths and thickness of active layer on the electrical characteristics of the TIPS-pentacene transistor. The interface states of the TIPS-pentacene thin-film transistors were investigated. The photocurrent mechanism of the transistors was also discussed. Some important morphology parameters of the TIPS-pentacene thin film such as roughness and grain size were determined. The electrical and photosensing parameters of the TIPS-pentacene transistor such as mobility, threshold voltage, sub-threshold swing value, photosensitivity, photoresponse, I on/I off ratio, interface trap density, total trap density and photoresponsivity under dark and white light illuminations were determined. It was found that the channel width and active layer thickness of the pentacene transistors play an imporant role on the photoresponse of the pentacene transistors. © 2012 Elsevier B.V. All rights reserved. Source

The surface morphology of the tris[4-(5-dicyanomethylidenemethyl-2-thienyl) phenyl]amine (TDCV-TPA) film was investigated by high performance atomic force microscopy and the surface roughness parameters such as roughness average (sa), root mean square roughness (sq), surface skewness (ssk) and surface kurtosis (sku) of the TDCV-TPA film were obtained. The TDCV-TPA film indicated the low valleys with bumpy surface. The optical properties of the solutions of the small-molecule semiconducting dye TDCV-TPA for different high molarities, lower molarities and different solvents were investigated in detail. The molar extinction coefficient, optical band gap, angle values of refraction of the TDCV-TPA decreased with increasing molarity, while the absorbance at maximum absorption wavelengths, angle of incidence, electric susceptibility, real part values of the optical conductivity of the TDCV-TPA increased with increasing molarity. The maximum molar extinction coefficient (εmax) at λmax values (510 and 509 nm) of the solutions of the TDCV-TPA for 0.024 and 0.010 mM were found to be 1.175 × 105 and 1.931 × 105 L mol-1 cm-1, respectively. The maximum mass extinction coefficient (αmax) of the solutions of the TDCV-TPA for 0.024 and 0.010 mM were found to be 163.226 and 268.247 L g-1 cm-1, respectively. The optical band gap (E g) values of the TDCV-TPA for 1, 2 and 3 mM were found to be 1.916, 1.898 and 1.892 eV, respectively. The absorption band edge for DCM varied from 1.882 to 1.997 eV, while the absorption band edge for chloroform varied from 1.923 to 2.027 eV. To obtain lower optical band gap of the TDCV-TPA can be prefered DCM solvent. © 2013 Elsevier B.V. All rights reserved. Source

Homopolymerization of 4-methoxybenzyl methacrylate (MBMA) and copolymerization with isobornyl methacrylate (IBMA) by the atom transfer radical polymerization method (ATRP) were performed at 90 °C. The homopolymer [poly(MBMA)] and copolymer [poly(MBMA-co-IBMA)] were characterized by Fourier transform infrared (FTIR), 1H and 13C NMR and gel permeation chromatography (GPC) techniques.. The compositions of the copolymers were calculated from 1H NMR spectra. For the atom transfer radical copolymerization system, their monomer reactivity ratios were obtained by using the Kelen-Tüdos and Fineman-Ross equation, as r1: 0.88, r 2: 0.63 (r1 is the monomer reactivity ratio of IBMA) and r 1: 0,90, r2 :0,65.The initial decomposition temperatures of the resultant copolymers decreased with an increasing mol fraction of IBMA, which indicates that the heat resistance of the copolymer has been improved by decreasing the MBMA units. Source

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