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The structural composition of soil organic matter (SOM) was determined in twenty-seven soils with different vegetation from several ecological zones of Australia and Pakistan using solid-state CPMAS 13C NMR. The SOM was characterized using carbon types derived from the NMR spectra. Relationships were determined between Koc (sorption per unit organic C) of carbaryl(1-naphthylmethylcarbamate) and phosalone (S-6-chloro-2,3-dihydro-2-oxobenzoxazol-3-ylmethyl O,O-diethyl phosphorodithioate) and the nature of organic matter in the soils. Substantial variations were revealed in the structural composition of organic matter in the soils studied. The variations in Koc values of the pesticides observed for the soils could be explained only when variations in the aromatic components of SOM were taken into consideration. The highly significant positive correlations of aromaticity of SOM and Koc values of carbaryl and phosalone revealed that the aromatic component of SOM is a good predictor of a soil's ability to bind such nonionic pesticides. 相似文献
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Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows 总被引:1,自引:0,他引:1
Robinson RS Pushpakumara PG Cheng Z Peters AR Abayasekara DR Wathes DC 《Reproduction (Cambridge, England)》2002,124(1):119-131
Alteration of the polyunsaturated fatty acid (PUFA) composition of milk by dietary supplementation of cows may be beneficial to human health. However, dietary PUFAs may influence synthesis of both prostaglandins and steroid hormones. This study examined the effects of dietary PUFAs on reproductive parameters in lactating cows. Cows were fed an isoenergetic control ration (n = 8) or a diet supplemented with LinPreme (n = 7) or SoyPreme (n = 8). These proprietary feeds are derived from linseed or soybeans and contain high concentrations of linolenic acid (LNA, n-3) or linoleic acid (LA, n-6) protected PUFA, respectively. Both PUFA-supplemented diets reduced plasma progesterone, particularly in the early luteal phase, and increased the number of medium-sized (5-10 mm in diameter) follicles. The diameter of the first dominant follicle, insulin-like growth factor I (IGF-I) concentrations at oestrus and cholesterol concentrations were all higher in cows fed a diet supplemented with LA (n-6) than in cows that did not receive this supplement. In cows fed a diet supplemented with LNA (n-3), there was an increase in oestradiol during the follicular phase. Diet had no effect on non-esterified fatty acid or insulin concentrations, or on the duration of the oestrous cycle. The plasma concentration of 13,14,dihydro-15 keto PGF(2alpha) after administration of 50 iu oxytocin was unaffected by diet on day 15 and day 16 of the oestrous cycle, but showed a greater response on day 17 in the LA (n-6) supplemented group. Therefore, the PUFA content of the diet can influence both ovarian and uterine function in cows. However, further studies using larger numbers of cows are required to test whether fertility is also affected by such diets. 相似文献
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纸的断裂韧性及其与纤维长度的关系 总被引:2,自引:0,他引:2
介绍了用断裂基功的概念测定纸张断裂韧性的新方法。并用此法研究了纤维长度对断裂韧性的影响,表明纸的断裂韧性与纤维长度几乎成直线关系;断裂韧性对纤维长度的依赖性比撕裂和抗张强度大。 相似文献
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Gomes AA Braga SP Cruz AG Cadena RS Lollo PC Carvalho C Amaya-Farfán J Faria JA Bolini HM 《Journal of dairy science》2011,94(10):4777-4786
The complex metabolism of probiotic bacteria requires several technological options to guarantee the functionally of probiotic dairy foods during the shelf life. This research aimed to evaluate the effect of the supplementation of increasing amounts of Lactobacillus acidophilus (0, 0.4, or 0.8 g/L of milk) on the physicochemical parameters and sensory acceptance of Minas fresh cheese. In addition, the sensory acceptance of probiotic cheeses was assessed using a consumer test and compared with commercial cheeses (conventional and probiotic). High counts (9.11 to 9.42 log cfu/g) of L. acidophilus were observed throughout the shelf life, which contributed to the maintenance of its probiotic status and resulted in lower pH values and greater production of organic acids. The probiotic cheeses presented lower scores for appearance, aroma, and texture compared with conventional cheeses. Internal preference mapping explained almost 60% of the total variation of the data and showed a large number of consumers concentrated near the conventional cheeses, demonstrating greater preference for these samples. The findings indicated that some negative sensory effects could occur when high level of supplementation with L. acidophilus is used in probiotic cheese processing. 相似文献
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Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins 总被引:1,自引:0,他引:1
This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al2O3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl− form). The catalysts were leached with aqua regia (75 °C, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L−1 HCl. Platinum was desorbed passing 1 mol L−1 Na2S2O3 (pH 9). Tin was removed by elution with 0.1 mol L−1 ascorbic acid. Indium was removed using 0.1 mol L−1 EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%). 相似文献