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61.
Polygonum multiflorum (PM) has been used as a tonic and anti-aging remedy for centuries in Asian countries. However, its application in the clinic has been hindered by its potential to cause liver injury and the lack of investigations into this mechanism. Here, we established a strategy using a network pharmacological technique combined with integrated pharmacokinetics to provide an applicable approach for addressing this issue. A fast and sensitive HPLC-QQQ-MS method was developed for the simultaneous quantification of five effective compounds (trans-2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside, emodin-8-O-β-d-glucoside, physcion-8-O-β-d-glucoside, aloe-emodin and emodin). The method was fully validated in terms of specificity, linearity, accuracy, precision, extraction recovery, matrix effects, and stability. The lower limits of quantification were 0.125–0.500 ng/mL. This well-validated method was successfully applied to an integrated pharmacokinetic study of PM extract in rats. The network pharmacological technique was used to evaluate the potential liver injury due to the five absorbed components. Through pathway enrichment analysis, it was found that potential liver injury is primarily associated with PI3K-Akt, MAPK, Rap1, and Ras signaling pathways. In brief, the combined strategy might be valuable in revealing the mechanism of potential liver injury due to PM.  相似文献   
62.
小白菜中残留虫酰肼的超临界流体萃取条件的研究   总被引:7,自引:0,他引:7  
杨立荣  张兴  陈安良  李广泽 《色谱》2004,22(3):263-266
将超临界流体萃取(supercritical fluid extraction,SFE)技术与高效液相色谱分析相结合,建立了特异性杀虫剂虫酰肼的萃取分离方法。SFE对虫酰肼的萃取条件:压力48.3 MPa(7000 psi),温度60 ℃,静态萃取时间20 min,CO2体积10 mL,改性剂甲醇添加量0.04 mL/g,丙酮为收集溶剂。在此条件下,SFE对虫酰肼的萃取率为100.75%,所得样品可直接用于高效液相色谱分析。色谱条件:紫外-二极管阵列检测器(检测波长为245 nm),C18键合色谱柱,乙腈  相似文献   
63.
Marker sets based on insertion/deletion polymorphisms (InDels) combine the characteristics of both short tandem repeats (STRs) and single nucleotide polymorphisms and have served as effective complementary or stand-alone systems for human identification in forensics. We developed a novel multiplex amplification detection system, designated the AGCU InDel 60 kit, containing 57 autosomal InDels, 2 Y-chromosomal InDels, and the amelogenin locus and validated the kit in a series of studies, which included tests of the PCR conditions; tests for sensitivity, species specificity, reproducibility, stability, and mock case samples; degradation studies; and a population study. The results indicated that the AGCU InDel 60 kit was accurate, specific, reproducible, stable, and robust. Complete DNA profiles were obtained even with 125 pg of human DNA. In tests of artificially degraded samples, we found that the number of alleles detected by the validated kit was considerably greater than that detected by the STR-based AGCU 21+1 kit, even as the degree of degradation increased. Additionally, 564 unrelated individuals from three Han groups were investigated using this novel system, and the values of combined power of discrimination and combined power of exclusion were not less than 1–4.9026 × 10−24 and 1–3.1123 × 10−5, respectively. Thus, the results indicated that the novel kit was more powerful than the previous version of the InDel kit (the AGCU InDel 50 kit). Our results suggest that the AGCU InDel 60 kit can serve as an efficient tool for human forensics and a supplementary kit for population genetics research.  相似文献   
64.
杨丽荣  江川  黎嘉骏  曹冲  周俊 《应用声学》2023,42(5):971-983
为了获取岩石破裂过程有效的声发射信号特征,更好的对岩石破裂状态进行分类,提出一种基于流形学习算法的LLE特征融合方法进行数据降维。以红砂岩为研究对象设计室内单轴压缩实验采集信号,然后对原始声发射信号预处理并对信号进行特征提取,以时域、频域下的特征向量重新组合成一组新的多维特征向量,采用线性主元(PCA)和流形学习LLE算法分别进行降维。比较两种算法降维后融合特征的聚类效果二维和三维分布图,使用LLE算法降维后,四种状态分布相对更近,呈一条水平线趋势,且各状态交叉混叠数目较少,第一状态没有一个样本错判,且四个状态相比于PCA降维后的聚类效果更集中。再比较两种算法降维后融合特征的敏感度之和,LLE算法融合特征敏感度之和远大于PCA算法,说明经过LLE算法降维后得到的融合特征更多地表征了原始信号包含的局部信息同时证明了LLE算法相比PCA算法具有更好的聚类效果。最后经LLE特征融合下的砂岩破裂状态分类实验验证,融合特征后的识别率相对单一的时域特征识别提高了6%。表明该方法能显著提高岩石破裂状态分类的识别率,降维性能相对突出。  相似文献   
65.
This paper develops availability and maintenance models for single‐unit systems subject to dependent hard and soft failures. A hard failure stops the system immediately, whereas a soft failure only reduces the performance capacity of the system. Dependence between these 2 types of failures is reflected in the fact that each soft failure directly increases the hazard rate of the hard failure. On the basis of such interaction, we derive recursive equations for the system reliability and availability functions. To detect both types of failures, inspections are executed periodically. Furthermore, we investigate the optimal inspection policy via the minimization of the expected cost per unit time. The applicability of the developed availability and maintenance models is validated by a case study on an electrical distribution system.  相似文献   
66.
发现了一种催化效率较高的消旋催化剂——CD550树脂,其与脂肪酶耦合可成功催化1-苯乙醇的动态动力学拆分(DKR).该树脂60℃下可将100 mmol/L(S)-1-苯乙醇于1.5 h内完全消旋.当其应用于1-苯乙醇的DKR反应时,通过采用结构较复杂的邻苯二酚二乙酸酯、间苯二酚二乙酸酯、3,5-二甲基苯酸乙酸酯作为酰基供体,可有效抑制树脂催化的底物无选择性转酯化,极大提高底物转化率和产物ee值.以邻苯二酚二乙酸酯参与的DKR反应为例,反应10 h,转化率大于99%,eeP为90.5%.  相似文献   
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69.
研究了水解聚安、黄原胶和木质素磺酸盐对中相微乳液相体积、粘度和界面张力的影响,实验结果表明:含有聚丙烯酰胺时,中相微乳液的相态、增溶参数、中相与下相间界面张力及中相粘度均无明显变化。生物聚合物对中相微乳液的物理影响也不大,木质素磺酸盐册对微乳液的形成产生明显影响;随着木质素磺酸盐浓度的增大,微乳液由中相转变为相,相应的物理参数亦有变化 。  相似文献   
70.
The title compound crystallizes in the monoclinic space group P21/c with unit cell parameters a = 3.8380(12), b = 11.994(4), and c = 16.245(5) Å, β = 90.743(5), V = 747.7(4) Å3, and Z = 4. The final reliability index is 0.0409 for 1088 observed reflections. All the non-hydrogen atoms in the title compound are almost coplanar, the largest deviation from the mean plane being 0.030(2) Å for atom C5. The crystal cohesion is accentuated by C–H⋅sN hydrogen bond. The X-ray crystallography analysis indicates that the methyl group is at the 5-position of the compound 4 rather than at the 7-position of the isomer 4-1. The preliminary biological test shows that the title compound has moderate herbicidal activity.  相似文献   
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