Economic Policy Uncertainty and Conditional Dependence between China and U.S. Stock Markets

In this paper, we investigate the impact of economic policy uncertainty (EPU) on the conditional dependence between China and U.S. stock markets by employing the Copula-mixed-data sampling (Copula-MIDAS) framework. In the case of EPU, we consider the global EPU (GEPU), the American EPU (AEPU), and the China EPU (CEPU). The empirical analysis based on the Shanghai Stock Exchange Composite (SSEC) index in China and the S&P 500 index in the U.S. shows that the tail dependence between China and U.S. stock markets is symmetrical, and the t Copula outperforms alternative Copulas in terms of in-sample goodness of fit. In particular, we find that the t Copula-MIDAS model with EPU dominates the traditional time-varying t Copula in terms of in-sample fitting. Moreover, we observe that both the GEPU and AEPU have a significantly positive impact on the conditional dependence between China and U.S. stock markets, whereas CEPU has no significant impact. The tail dependence between China and U.S. stock markets exhibits an increasing trend, particularly in the recent years.

Both Baicalein and Gallocatechin Gallate Efficaciously Inhibit SARS-CoV-2 Replication by Targeting Mpro and Sepsis in Mice (preprint)

Severe acute syndrome coronavirus 2(SARS-CoV-2) caused the global pandemic of COVID-19 since December 2019. Although most of COVID-19’s patients are mild or common, most of the severe patients have sepsis caused by the cytokine storm, which greatly increases the case fatality rate. Moreover, there is no effective drug that can resist the novel coronavirus so far, so it’s urgent to develop antiviral drug for the SARS-CoV-2. In our research, we screened 29 compounds with a score lower than -6 from 35 flavonoid compounds by molecular docking. (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were identified to have potent inhibit activity with IC50 5.774±0.805μM, 13.14±2.081μM and 5.158±0.928μM by FRET assay. Subsequently, we conducted molecular docking experiments, which showed that (-)-Gallocatechin gallate, (+)-Gallocatechin and Baicalein were non-covalently bound to Mpro through π-π stacking and hydrogen bonds in the Cys145 catalytic site. We further evaluated the effect of (-)-Gallocatechin gallate and Baicalein on cytokine storm use a mouse model of sepsis. (-)-Gallocatechin gallate and Baicalein significant reduced sepsis severity based on weight, murine sepsis score and survival rate and reduced the inflammatory factors level such as TNF-α, IL-1α, IL-4 and IL-10.  Overall, (-)-Gallocatechin gallate and Baicalein may be potential drugs for symptomatic treatment of COVID-19.