2,414 research outputs found

    Insecticidal Effect of the Extracts of Cladonia foliacea (Huds.) Willd. and Flavoparmelia caperata (L.) Hale AgainstAdults of the Grain Weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae)

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    Four different concentrations of extracts, obtained from the two lichen species (Cladonia foliacea (Huds.) Willd. and Flavoparmelia caperata (L.) Hale), were tested against the grain weevil, Sitophilus granaries (L.) under laboratory conditions. Mortality rate of adults was determined at 24, 48, and 96 h. Obtained results showed that the extracts of C. foliacea and F. caperata had insecticidal effects on the adults of S. granarius in comparison with control. The insecticidal effect was influenced by the concentration of the extract and the exposure time. Higher concentrations and longer exposure time resulted to highest toxicity levels on S. granarius. Mortality rates after 96 h of treatment with highest concentration (20 mg.ml-1) of the extracts of F. caperata and C. foliacea were determined as 91 and 83%, respectively. Bioassay revealed that 96 h LC50 values were 0.107 and 0.354 mg.ml-1, respectively. The results suggest that lichen compounds could be useful as alternatives of pesticides

    Mutagenic and antimutagenic properties of some lichen species grown in the Eastern Anatolia Region of Turkey

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    All the methanol extracts did not show mutagenic activity in Ames/Salmonella and Z. mays MI test systems. Furthermore, some extracts showed significant antimutagenic activity against 9-AA in Ames test system. Inhibition rates for 9-AA mutagenicity ranged from 25.51 % (P. furfuracea – 0.05 μg/plate) to 66.14 % (C. islandica – 0.05 μg/plate). In addition, all of the extracts showed significant antimutagenic activity against sodium azide (NaN₃) mutagenicity on MI values of Z. mays.Целью работы было изучить мутагенный и антимутагенный потенциал метанольных экстрактов Cetraria islandica (L.) Ach. (Parmeliaceae), Pseudevernia furfuracea (L.) Zopf (Parmeliaceae) и Xanthoparmelia somloënsis (Gyeln.) Hale (Parmeliaceae) – лишайников из восточной части Турции. Ни один из экстрактов не показал мутагенной активности в тестах Эймса и Z. mays MI. Более того, некоторые экстракты проявляли заметную антимутагенную активность против 9-амино-акридина в тесте Эймса. Уровень ингибирования варьировал от 25,51 % (P. furfuracea) до 66,14 % (C. islandica). Кроме того, все экстракты проявляли значительную антимутагенную активность против азида натрия в Z. mays MI тесте. Все экстракты могут считаться генотоксично безопасными в исследованных концентрациях

    Modeling the kinetics of peroxidase inactivation, colour and texture changes of Portuguese cabbage (Brassica oleracea L. var. costata DC) during UV-C light and heat blanching

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    The e ects of heat blanching and UV-C light followed by heat on Portuguese cabbage peroxidase (POD), colour and texture were studied in the temperature range of 80-95 °C. POD inactivation, lightness (L) and yellowness (b) colour changes were described by a rst-order reaction model. The greenness (a) colour and texture ( rmness) changes followed a two fraction kinetic model behaviour. The temperature e ect was well described by the Arrhenius law. At lower temperatures the combined treatment showed higher POD inactivation. Colour and texture parameters did not show signi cant di erences between treatments. Long processing times turned the leaves slightly darker, decreased greenness, yellowness and rmness. Short processing times increased the rmness and greenness of the leaves. The treatment at 80 °C for 90 seconds reduced 90% of POD, retaining 98% of lightness and 92% of yellowness and improved the green colour (130%) and rmness (125%). At 80 °C the heat blanching required 7.4 min to inactivate 90% of the enzyme activity, reducing lightness, greenness, yellowness and rmness to 92%, 68%, 62% and 61%, respectively. The present ndings will help to optimize the Portuguese cabbage blanching conditions.info:eu-repo/semantics/publishedVersio

    Nanomechanical characterization by double-pass force-distance mapping

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    Cataloged from PDF version of article.We demonstrate high speed force–distance mapping using a double-pass scheme. The topography is measured in tapping mode in the first pass and this information is used in the second pass to move the tip over the sample. In the second pass, the cantilever dither signal is turned off and the sample is vibrated. Rapid (few kHz frequency) force–distance curves can be recorded with small peak interaction force, and can be processed into an image. Such a double-pass measurement eliminates the need for feedback during force–distance measurements. The method is demonstrated on self-assembled peptidic nanofibers

    The iridium double perovskite Sr2YIrO6 revisited: A combined structural and specific heat study

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    Recently, the iridate double perovskite Sr2_2YIrO6_6 has attracted considerable attention due to the report of unexpected magnetism in this Ir5+^{5+} (5d4^4) material, in which according to the Jeff_{eff} model, a non-magnetic ground state is expected. However, in recent works on polycrystalline samples of the series Ba2x_{2-x}Srx_xYIrO6_6 no indication of magnetic transitions have been found. We present a structural, magnetic and thermodynamic characterization of Sr2_2YIrO6_6 single crystals, with emphasis on the temperature and magnetic field dependence of the specific heat. Here, we demonstrate the clue role of single crystal X-ray diffraction on the structural characterization of the Sr2_2YIrO6_6 double perovskite crystals by reporting the detection of a 2a×2a×1c\sqrt{2}a \times \sqrt{2}a \times 1c supercell, where aa, bb and cc are the unit cell dimensions of the reported monoclinic subcell. In agreement with the expected non-magnetic ground state of Ir5+^{5+} (5d4^4) in Sr2_2YIrO6_6, no magnetic transition is observed down to 430~mK. Moreover, our results suggest that the low temperature anomaly observed in the specific heat is not related to the onset of long-range magnetic order. Instead, it is identified as a Schottky anomaly caused by paramagnetic impurities present in the sample, of the order of n0.5(2)n \sim 0.5(2) \%. These impurities lead to non-negligible spin correlations, which nonetheless, are not associated with long-range magnetic ordering.Comment: 20 pages, 10 figure

    A model for shock wave chaos

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    We propose the following model equation: ut+1/2(u2uus)x=f(x,us),u_{t}+1/2(u^{2}-uu_{s})_{x}=f(x,u_{s}), that predicts chaotic shock waves. It is given on the half-line x<0x<0 and the shock is located at x=0x=0 for any t0t\ge0. Here us(t)u_{s}(t) is the shock state and the source term ff is assumed to satisfy certain integrability constraints as explained in the main text. We demonstrate that this simple equation reproduces many of the properties of detonations in gaseous mixtures, which one finds by solving the reactive Euler equations: existence of steady traveling-wave solutions and their instability, a cascade of period-doubling bifurcations, onset of chaos, and shock formation in the reaction zone.Comment: 4 pages, 4 figure

    Universality of the Ising and the S=1 model on Archimedean lattices: A Monte Carlo determination

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    The Ising model S=1/2 and the S=1 model are studied by efficient Monte Carlo schemes on the (3,4,6,4) and the (3,3,3,3,6) Archimedean lattices. The algorithms used, a hybrid Metropolis-Wolff algorithm and a parallel tempering protocol, are briefly described and compared with the simple Metropolis algorithm. Accurate Monte Carlo data are produced at the exact critical temperatures of the Ising model for these lattices. Their finite-size analysis provide, with high accuracy, all critical exponents which, as expected, are the same with the well known 2d Ising model exact values. A detailed finite-size scaling analysis of our Monte Carlo data for the S=1 model on the same lattices provides very clear evidence that this model obeys, also very well, the 2d Ising model critical exponents. As a result, we find that recent Monte Carlo simulations and attempts to define effective dimensionality for the S=1 model on these lattices are misleading. Accurate estimates are obtained for the critical amplitudes of the logarithmic expansions of the specific heat for both models on the two Archimedean lattices.Comment: 9 pages, 11 figure

    Photoperiod effects on carcass traits, meat quality, and stress response in heart and lung of broilers

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    This study evaluated effects of photoperiod treatments on slaughter and carcass traits, meat quality, indicators of oxidative stress, and heat shock protein 70 (Hsp70) levels of lung and heart tissues in broilers. Five hundred Ross 308 broiler chicks were used. The treatments consisted of 23 hours of continuous light and one hour of darkness (23L1D), four hours of light followed by two hours of darkness (4L2D), eight hours of light and four hours of darkness (8L4D), and 16 hours of light and eight hours of darkness (16L8D). After 42 days, two birds from each replicate were slaughtered. Birds that had been subjected to 16L8D had lower slaughter, carcass, and breast weights than the other treatments. Significant correlations were observed for slaughter, carcass and breast weights and white stripe. At 10 min post mortem, the pH of the breast was the highest in 23L1D. Breasts from birds subjected to 23L1D and 16L8D had most fat and least protein, while white striping was not different among treatments. The 4L2D treatment resulted in the highest lung glutathione (GSH) concentration. Malondialdehyde (MDA) and GSH concentrations in the heart tissues of broilers from 8L4D and 4L2D were greater than those from 23L1D and 16:8. Glutathione peroxidase (GSH-Px) and superoxide dismutase concentrations were greatest for birds subjected to 16L8D. Heat shock protein 70 was lowest in lung and heart from birds subjected to 8L4D. Thus, shorter and more frequent periods of darkness can be recommended for welfare with little compromise in performance. Keywords: carcass quality, heat shock protein 70, oxidative stress, white strip
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