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Methane (CH4) is a potent greenhouse gas and the huge CH4 fluxes emitted from paddy fields can prejudice the eco-compatibility of rice cultivation. CH4 production in submerged rice crops is known to be highly influenced by water temperature. Hence, lowering ponding water temperature (LPWT) could be an option to mitigate CH4 emissions from paddy environments when it is possible either to irrigate with slightly colder water or to increase ponding water depth. However, paddy soil is a complex environment in which many processes are simultaneously influenced by temperature, leading to a difficult prediction of LPWT effects. For this reason, LPWT efficiency is here theoretically investigated with a one-dimensional process-based model that simulates the vertical and temporal dynamics of water temperature in soil and the fate of chemical compounds that influence CH4 emissions. The model is validated with literature measured data of CH4 emissions from a paddy field under time-variable temperature regime. Based on modeling results, LPWT appears promising since the simulated reduction of CH4 emissions reaches about −12% and −49% for an LPWT equal to −5 °C during the ripening stage only (last 30 days of growing season, when rice is less sensitive to temperature variations) and −2 °C over the whole growing season, respectively. LPWT affects CH4 emissions either directly (decreasing methanogenic activity), indirectly (decreasing activity of bacteria using alternative electron acceptors), or both. The encouraging results provide the theoretical ground for further laboratory and field studies aimed to investigate the LPWT feasibility in paddy environments. 相似文献
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亚麻酸磷脂软胶囊降血脂药理作用 总被引:1,自引:0,他引:1
[目的]研究亚麻酸磷脂软胶囊对混合型高脂血症大鼠的降血脂作用。[方法]84只SPF级健康成年雄性SD大鼠,随机分成2组:空白对照组和模型组,空白对照组大鼠给予维持饲料,模型组给予模型饲料。模型组造模成功,从模型组动物中筛选出60只大鼠,按血清总胆固醇水平随机分成4个剂量组和1个模型对照组,每组12只;空白对照组12只大鼠全部参与试验。3个剂量组分别以333、667、2 000 mg/kg剂量(分别相当于人拟用剂量的5、10、30倍)的亚麻酸磷脂软胶囊给各剂量组大鼠灌胃30 d,模型对照组和空白对照组大鼠给予等体积的橄榄油。[结果]模型对照组大鼠血清总胆固醇、甘油三酯、低密度脂蛋白-胆固醇水平显著高于空白对照组,差异均有统计学意义(P0.05或0.01);高剂量组大鼠血清总胆固醇和血清甘油三酯水平显著低于模型对照组,中、高剂量组大鼠血清低密度脂蛋白-胆固醇水平明显低于模型对照组,差异均有统计学意义(P0.05或0.01);高剂量组大鼠血清低密度脂蛋白-胆固醇水平明显低于参照组,差异均有统计学意义(P0.05或0.01);各剂量组血清高密度脂蛋白-胆固醇水平与模型对照组比较,差异无统计学意义(P0.05)。[结论]亚麻酸磷脂软胶囊对雄性SD大鼠具有辅助降血脂的功能。 相似文献
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对全蚕粉和全蚕粉复合物用60Co γ射线7kGy辐照灭菌处理后,按国家标准GB/T4789.2-2003检验菌落总数,结果表明,辐照组菌落总数显著低于未辐照对照组,达到了食品、中药制品卫生要求,且对1-脱氧野尻霉素(1-DNJ)含量和降血糖效果均无明显影响。将辐照处理的全蚕粉和全蚕粉复合物分别置于常温和冷藏条件下保存6个月,发现未辐照灭菌的样品菌落数显著增加,而辐照灭菌样品菌落数、1-DNJ含量和降血糖效果与储存前相比均无显著差异,但小鼠的餐后血糖值以辐照冷藏组较低。结果说明,60Co γ射线7kGy辐照可以有效杀灭全蚕粉和全蚕粉复合物中的微生物,而对其有效成分1-DNJ和降血糖效果无影响。 相似文献
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全蚕粉(SP)降血糖的作用效果及其机理的研究 总被引:36,自引:11,他引:25
研究了全蚕粉及其对实验鼠降血糖的作用。初步检测发现全蚕粉中含有三碘甲腺原氨酸 (T3) ,不含甲状腺素T4。试验证明全蚕粉具有显著降血糖的效果。添加 0 1%的全蚕粉饲喂高血糖实验鼠 4周 ,摄食后 1h和 2h的血糖值分别降低了 13 81% (p <0 0 5 )和 11 0 7%。T淋巴细胞转化率提高 35 % (p <0 0 1)。实验还对全蚕粉降血糖的作用机理进行了探讨 ,认为全蚕粉的降血糖作用可能与抑制小肠粘膜α 麦芽糖苷酶活性有关 相似文献