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排序方式: 共有1868条查询结果,搜索用时 62 毫秒
31.
目的:建立用高效液相色谱法同时测定果脯佛手中甘草苷和甘草酸含量的方法.方法:采用LiChmspher RP—C18色谱柱,以乙腈-水(1.2%甲酸)为流动相,梯度洗脱,检测波长254nm.结果:甘草苷在0.21-3.15μg范围内呈良好的线性关系,回归方程为Y=1053.9644X-0.0528(r=0.9999),平均回收率为99.7%,RSD为1.72%(n=9),重复性RSD为0.14%;甘草酸铵在0.25—6.25μg范围内呈良好的线性关系,回归方程为Y=1311.3875X-14.3144(r=0.9998),平均回收率为100.8%,RSD为1.31%(n=9),重复性RSD为0.40%.结论:方法操作简便,结果可靠,重现性好. 相似文献
32.
33.
Yangxueqingnao particles inhibit rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid 总被引:1,自引:0,他引:1
Cai W Xu Y Chen JZ Huang SR Lu ZY Wang ZK 《Journal of Zhejiang University. Science. B》2005,6(9):892-896
Objective: To observe the effect of Yangxueqingnao particles on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). Methods: The amount of3H-TdR (3H-thymidine) admixed in cultured rat VSMC was measured and mitogen-activated protein kinase (MAPK) activity and lipid peroxidation end product malondialdehyde (MDA)content of the VSMC were assayed. Results: 1×10-9, 1×10-8, 1×10-7 mol/L LPA in a concentration dependent manner, induced the amount of 3H-TdR admixed, MAP kinase activity, and MDA content of the cultured rat VSMC to increase. However, 5%, 10%,and 15% Yangxueqingnao serum preincubation resulted in a decrease of 23.0%, 42.0%, and 52.0% (P<0.01) respectively in the amount of 3H-TdR admixed, a decline in VSMC MAP kinase activity of 13.9% (P<0.05), 29.6% (P<0.01), and 48.9% (P<0.01)respectively, and also, a decrease in MDA content of VSMC of 19.4%, 24.7%, and 43.2% (P<0.01) respectively, in the 1×10-7mol/L LPA-treated VSMC. Conclusions: LPA activates the proliferation and lipid peroxidation of VSMC in a concentration dependent manner. The LPA-induced VSMC proliferation is related to the activity of MAP kinases, enzymes involved in an intracellular signalling pathway. The results of the present study showed that Yangxueqingnao particles can effectively inhibit LPA-induced VSMC proliferation, MAP kinase activation, and reduce lipid peroxidative lesion. 相似文献
34.
陆英中乌索酸的分离制备及HPLC分析(Ⅲ) 总被引:3,自引:2,他引:3
目的:分离制备陆英中的乌索酸,并建立其含量测定方法.方法:采用“醇提凝析法”分离制备乌索酸,HPLC法测定其含量,色谱柱为Symmetry Shield RP18,流动相为甲醇-水(88:12),流速1ml/min,检测波长220nm,柱温25℃.结果:乌索酸在4.6~23.0μg范围内线性关系良好(r=0.9999),平均回收率为99.82%(RSD为0.75%).结论:“醇提凝析法”分离制备乌索酸工艺先进,实用可行;HPLC法测定乌索酸含量准确、可靠,可用于乌索酸含量测定分析。 相似文献
36.
柠檬酸在肉鸡日粮中占0.5%,试验结果比对照组增重提高6.1%,公斤增重成本下降7.4%,成活率提高8.6%,鸡新城疫抗体效价提高1倍以上,饲料报酬与经济效益得到了明显的提高. 相似文献
37.
研究了黄嘌呤在多壁炭纳米管化学修饰的玻炭电极上的伏安行为,其结果表明,在0.1mol·L-1磷酸盐(pH=6.5)介质中,修饰电极对黄嘌呤具有强力的吸附催化作用,其催化电流与黄嘌呤浓度在310-8~610-5mol·L-1范围内线性关系,检出限为110-8mol·L-1. 利用本法测定了人体血清中黄嘌呤的含量,效果颇佳. 相似文献
38.
39.
Phytoremediation is emerging as a potential cost-effective solution for remediation of contaminated soils, and bioavailability
of metal in the soil for plant uptake is an important factor for successful phytoremediation. This study aimed at investigating
the ability of EDTA and citric acid for enhancing soil bioavailability of Cu and phytoremediation by Elsholtzia splendens
in two types of soils contaminated with heavy metals [i.e. mined soil from copper mining area (MS), and paddy soil (PS) polluted
by copper refining]. The results showed that addition of 2.5 mmol/kg EDTA significantly increased the H2O extractable Cu concentration from 1.20 to 15.78 mg/kg in MS and from 0.26 to 15.72 mg/kg in PS, and that shoot Cu concentration
increased 4-fold and 8-fold as compared to the control. There was no significant difference between the treatment with 5.0
mmol/kg EDTA and that with 2.5 mmol/kg EDTA, probably because that 2.5 mmol/kg EDTA was enough for elevating Cu bioavailability
to the maximum level. As compared with the control, citric acid had no marked effect on both soil extractable Cu and shoot
Cu concentration or accumulation. The results indicated that EDTA addition can increase the potential and efficiency of Cu
phytoextraction byE. splendens in polluted soils.
Project supported by the National Natural Science Foundation of China (No. 29977017) and the Science and Technology Ministry
of China (No. 2002CB410804) 相似文献
40.
尽管支链氨基酸在运动过程中提供的能量很少,但它却与运动能力有密切的关系.本文从体内支链氨基酸的代谢途径;运动对支链氨基酸代谢的影响;以及补充支链氨基酸提高运动能力的机理等方面综述了支链氨基酸与运动能力关系的研究进展. 相似文献