Zhishi Xiebai Guizhi Decoction for coronary heart disease: A systematic review and meta-analysis.

BACKGROUND: Coronary heart disease (CHD) is a type of cardiovascular disease (CVD) caused by coronary atherosclerosis. It is a main cause of medical burden and cardiovascular related death. Zhishi Xiebai Guizhi Decoction (ZXGD) is a representative prescription of traditional Chinese medicine (TCM) in the treatment of CHD, but there is poor systemically evidence-based appraisal. OBJECTIVE: To evaluate the efficacy and safety of ZXGD for CHD. METHODS: Eight databases were retrieved for randomized controlled trials (RCTs). Data was extracted independently by 2 reviewers. The quality of the included studies was assessed by Cochrane Collaboration risk of bias tool. Clinical efficacy, blood lipid, vascular endothelial function, inflammatory factor and homocysteine (Hcy) were prespecified outcome measures. RESULTS: Twenty-four studies (2272 patients) were included. Meta-analysis showed that compared with conventional western medicine (WM) alone, ZXGD was associated with a greater symptom improvement rate with a relative risk (RR) of 1.21 [95% CI (1.16, 1.26), P < .00001] and a greater electrocardiogram (ECG) improvement rate with a RR of 1.27 [95% CI (1.16, 1.40), P < .00001]. In terms of blood lipid, ZXGD reduced total cholesterol (TC) with a mean difference (MD) of -1.15 [95%CI (-1.75, -0.55), P = .0002] and triglyceride (TG) [MD = -0.72, 95%CI (-0.99, -0.45), P < .00001], reduced low-density lipoprotein cholesterol (LDL-C) [MD = -0.93, 95% CI (-1.17, -0.69), P < .00001], and increased high-density lipoprotein cholesterol (HDL-C) [MD = 0.31, 95%CI (0.20, 0.42), P < .00001]. In terms of vascular endothelial function, ZXGD decreased the level of endothelin-1 (ET-1) [MD = -7.81, 95%CI (-9.51, -6.10), P < .00001], and increased nitric oxide (NO) [MD = 8.90, 95%CI (7.86, 9.93), P < .00001]. ZXGD also reduced high-sensitivity C-reactive protein (hs-CRP) [MD = -1.73, 95% CI (-2.63, -0.83), P < .00001] and Hcy [MD = -2.03, 95%CI (-2.78, -1.28), P < .00001]. No significant differences were found in adverse event rate between the 2 groups with a RR of 0.77 [95% CI (0.44, 1.34), P = .36]. CONCLUSION: ZXGD is effective and safe in the treatment of CHD. However, more rigorous and high-quality RCTs are needed to verify the conclusion.

The Precipitation of Niobium Carbide and Its Influence on the Structure of HT250 for Automobile Wheel Hubs.

Improving the strength of grey cast iron wheel hubs will improve the safety of automobiles and have a great significance for energy saving and environmental protection. This paper systematically compares the calculation results of Python-based precipitation calculation and JmatPro software simulation with experiments. The results show that with a low mass fraction of niobium (0.098%) cuboid Niobium Carbide (NbC) precipitates do not form in the liquid phase; however, an elongated NbC niobium-rich phase may form during the solidification process and in the solid phase. However, cuboid NbC precipitates can be precipitated from the liquid phase when the niobium mass fraction is higher (0.27%, 0.46%). These results indicate that with the increasing niobium content the amount, particle size, and initial precipitation temperature of niobium carbide precipitated in the matrix structure will increase. According to the observation and statistical analysis of the microstructure, it is found that tensile strength will be improved with an increase in niobium content due to the refinement of the graphite and pearlite interlamellar spacing. In this paper, adding less than 0.32% of Nb to grey cast iron is recommended, considering the comprehensive cost and the effect of niobium in the material structure.