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1.
Land‐cover change can alter the spatiotemporal distribution of water inputs to mountain ecosystems, an important control on land‐surface and land‐atmosphere hydrologic fluxes. In eastern Mexico, we examined the influence of three widespread land‐cover types, montane cloud forest, coffee agroforestry, and cleared areas, on total and net water inputs to soil. Stand structural characteristics, as well as rain, fog, stemflow, and throughfall (water that falls through the canopy) water fluxes were measured across 11 sites during wet and dry seasons from 2005 to 2008. Land‐cover type had a significant effect on annual and seasonal net throughfall (NTF <0=canopy water retention plus canopy evaporation; NTF >0=fog water deposition). Forest canopies retained and/or lost to evaporation (i.e. NTF<0) five‐ to 11‐fold more water than coffee agroforests. Moreover, stemflow was fourfold higher under coffee shade than forest trees. Precipitation seasonality and phenological patterns determined the magnitude of these land‐cover differences, as well as their implications for the hydrologic cycle. Significant negative relationships were found between NTF and tree leaf area index (R2=0.38, P<0.002), NTF and stand basal area (R2=0.664, P<0.002), and stemflow and epiphyte loading (R2=0.414, P<0.001). These findings indicate that leaf and epiphyte surface area reductions associated with forest conversion decrease canopy water retention/evaporation, thereby increasing throughfall and stemflow inputs to soil. Interannual precipitation variability also altered patterns of water redistribution across this landscape. Storms and hurricanes resulted in little difference in forest‐coffee wet season NTF, while El Niño Southern Oscillation was associated with a twofold increase in dry season rain and fog throughfall water deposition. In montane headwater regions, changes in water delivery to canopies and soils may affect infiltration, runoff, and evapotranspiration, with implications for provisioning (e.g. water supply) and regulating (e.g. flood mitigation) ecosystem services.  相似文献   
2.
For some foodstuffs, determination of the mycotoxin ochratoxin A (OTA) requires time consuming clean up by means of solid phase extraction (SPE). Therefore a system for automated SPE was tested for cleaning up roasted coffee as a possible way of shortening preparation time. Validation of the method in accordance to the so called “Concept '98” led to a LOD of 0.2 μg/kg and a recovery rate of 92%. By using the described procedure with samples of roasted coffee the OTA contents varied between the LOD and 3.4 μg/kg. This method was also used to determine ochratoxin A in liquorice roots, ginger and valerian.
Presented at the 26th Mykotoxin Workshop in Herrsching, Germany, May 17–19, 2004  相似文献   
3.
The heat stability of ochratoxin A in green coffee beans inoculated with Aspergillus ochraceus was studied. Heat treatment (roasting) at 200 °C for 10 or 20 min reduced the levels of ochratoxin A by only 0–12% in the dried whole beans. Almost all of the ochratoxin A was infused into the coffee decoction when the roasted samples were ground and extracted with boiling water. Therefore, the reduction of ochratoxin A concentration of contaminated coffee beans by roasting under these conditions is ineffective.  相似文献   
4.
The anti- and pro-oxidative effects of phenolic compounds and antioxidants were studied in two different in vitro model systems utilizing ethyl linoleate and 2′-deoxyguanosine (2′-dG) as oxidative substrates, and a Fenton reaction (H2O2, Fe2+) to initiate oxidation. Oxidation of the biomolecules in both model systems exhibited dose dependency. In the 2′-dG assay, oxidation was closely related to H2O2 generation, which occurred during autoxidation of the phenolics. Hydroxylating activity was greatly enhanced by Mn2+ and Cu2+, but not by Zn2+ or Co2+. Ethyl linoleate peroxidation was inhibited by low concentrations of catechol, quercitin, and instant coffee. However, peroxidation was promoted by high concentrations of the same compounds, probably by recycling of chelated inactive Fe3+ to the active Fe2+ state.  相似文献   
5.
6.
一、云南植胶区的自然地理条件云南橡胶种植区位于云南高原南部,北纬20°09′—24°59′,东经93°31′—105°08′,海拔100—1000m之间的热带季风地区。包括文山、红河、思茅、西双版纳、临沧和德宏地区  相似文献   
7.
Malathion (MAL) is an organophosphate insecticide that disrupts the body's antioxidant system; it is one of the earliest organophosphate insecticides extensively used as dust, emulsion, and vapor control a wide variety of insect pests under different conditions. This experimentation aims to evaluate the influence of Arabica coffee oil and olive oil on MAL-induced nephrotoxicity in male rat. 6 sets bearing the same number of animals were applied to this experiment. Each set comprised 10 rats. The first set of rats was used as the control group; rats in the second set were exposed to MAL measured at 100 mg/kg body weight for 7 weeks. Animals in the third and fourth set were treated with 400 mg/kg body weight of Arabica coffee oil and olive oil, and 100 mg/kg body weight of MAL. The fifth, together with the sixth set, were fed with a similar proportion of Arabica coffee oil and olive oil as administered to the third set of rats. After the experimental duration, rats of group 2 showed severe biochemical alterations, including significant increases of creatinine, uric acids, and urea nitrogen (BUN), resulting in marked decreases in serum albumin values and total protein (TP). Severe histopathological and immunohistochemical alterations of kidney tissues were observed in exposed MAL-intoxicated rats. Administration of these oils reduced the detected biochemical, histopathological modifications caused by MAL intoxication. Two active ingredients in Arabica coffee oil (oleic acid) and olive oil (hydroxytyrosol) showed good cyclooxygenase-2 (COX 2) interaction. Moreover, oleic acid from coffee oil and olive oil exhibited impressive association with xanthine oxidase (XO). The current finding showed that coffee oil and olive oil could be appraised as possible and a likely deterrence component against nephrotoxicity brought about by MAL.  相似文献   
8.
陈磊  杨帅  杨磊  杨佳敏  沈小雨  孙洁  任晓暄  朱文莲  张露芬 《生物磁学》2013,(34):6634-6637,6736
目的:比较即刻电针天枢穴、足三里穴对肠易激综合征(ms)模型大鼠血浆降钙基因相关肽(CGRP)、内皮素(ET)水平及结肠组织中内皮素受体A(ETR-A)、CGRPmRNA表达的影响,旨在探讨电针即刻治疗IBS的部分机制。方法:采用WISTAR幼鼠制备肠易激综合征模型,随机分为空白对照组、模型组、天枢组、足三里组,每组8只。空白对照组不作任何处理,模型组只束缚不针刺,天枢组和足三里组在实验第8周电针治疗一次,留针20min。治疗结束后处死大鼠,取大鼠血浆及部分结肠组织进行生物活性物质检测。采用酶联免疫法检测血浆中CGRP、ET、结肠组织中ETR—A的含量,采用RT—PCR法检测结肠组织中CGRPmRNA表达。结果:(1)即刻电针对IBS模型大鼠血浆CGRP、ET水平的影响:与空白对照组比较,模型组CGRP水平明显降低(P〈0.01);与模型组比较,天枢组、足三里组CGRP水平明显升高(P〈0.01)。与空白对照组比较,模型组ET水平升高(P〈0.05);与模型组比较,天枢组ET水平明显降低(P〈0.01)。(2)即刻电针对IBS模型大鼠结肠组织ETR—A水平的影响:与空白对照组比较,模型组ETR—A水平明显升高(P〈0.01);与模型组比较,足三里组ETR-A水平明显降低(P〈0.01)。(3)即刻电针对IBS模型大鼠结肠组织CGRPmRNA表达的影响:与空白对照组比较,模型组、天枢组、足三里组CGRPmRNA表达明显增强(P〈0.01,P〈0.05);与模型组比较,足三里组CGRPmRNA表达减弱(P〈0.05)。结论:即刻电针介入后,能够调节机体的内环境紊乱和CGRP、ET的平衡失调。这种调节作用因穴位不同而具有不同的特点,天枢穴对血浆中CGRP、ET调节作用较强,足三里穴在受体和基因表达方面作用明显。  相似文献   
9.
Roasted almond volatiles were separated into basic, carbonyl and non-carbonyl fractions. Each fraction was analyzed by combination gas chromatography-mass spectrometry. Twenty-five compounds, in addition to eighteen known components, were identified. Many of the components identified were considered to contribute to the overall flavor. 2,5-Dimethyl-4- hydroxy-3(2H)-furanone, which was identified from methanol extract of roasted almond, seemed to make the largest contribution to the sweet aroma of roasted almond.  相似文献   
10.
A coffee extract significantly suppressed lipopolysaccharide (LPS)-induced hepatitis in D-galactosamine-sensitized rats, as assessed by the plasma alanine and aspartate aminotransferase activities, when it was added to the diet (30 g/kg) and fed to rats for 14 days. Its effect was as strong as that of a green tea extract. The coffee extract suppressed LPS-induced hepatitis when singly force-fed (1.2 g/kg) 1.5 h prior to the injection of the drugs, whereas a decaffeinated cofee extract had no significant effect. The hepatoprotective effect of caffeine was stronger than that of theobromine. These results indicate that coffee can protect animals from LPS-induced hepatitis, and that the effect of coffee might be mainly due to caffeine.  相似文献   
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