Infectious disease equity market volatility, geopolitical risk, speculation, and commodity returns: Comparative analysis of five epidemic outbreaks.

This paper uses a time-varying Granger causality test and time-varying parameter vector autoregression with stochastic volatility model to analyze the effects of infectious disease equity market volatility (ID-EMV), geopolitical risk (GPR), and speculation on commodity returns. The time-varying effects of ID-EMV, GPR, and speculation on commodity returns are investigated and compared in five epidemics during 1998-2021: Bird Flu in 1998, SARS in 2003, Swine Flu in 2009, MERS and Ebola in 2014, and COVID-19 in 2019. A further analysis is performed for five commodity subcategories of textiles, industry, metals, livestock, and food. Results show that time-varying effects are significant, and most responses to ID-EMV are positive, to GPR are changing from negative to positive, and to speculation are negative. Notably, ID-EMV in the ongoing COVID-19 pandemic is the worst hit to commodity returns in more than two decades.

Financial contagion effects of major crises in African stock markets

This study examines financial contagion effects in African stock markets during major crises over the period 2005 to 2020. We investigate contagion effects in individual stock markets and from a regional perspective using dynamic conditional correlations during the global financial crisis, European debt crisis, Brexit, and COVID-19. The empirical evidence confirms contagion effects in some individual markets. However, significant evidence of contagion is found only during the global financial crisis from the regional perspective. Our findings suggest that the regional impacts of crises differ due to the nature of those crises. We also find financial contagion increases in the country-level risk, market capitalization and export to GDP and decreases in corruption.

Dynamic Continuum of Nanoscale Peptide Assemblies Facilitates Endocytosis and Endosomal Escape.

Alkaline phosphatase (ALP) enables intracellular targeting by peptide assemblies, but how the ALP substrates enter cells remains elusive. Here we show that nanoscale phosphopeptide assemblies cluster ALP to enable caveolae-mediated endocytosis (CME) and endosomal escape. Specifically, fluorescent phosphopeptides undergo enzyme-catalyzed self-assembly to form nanofibers. Live cell imaging unveils that phosphopeptides nanoparticles, coincubated with HEK293 cells overexpressing red fluorescent protein-tagged tissue-nonspecific ALP (TNAP-RFP), cluster TNAP-RFP in lipid rafts to enable CME. Further dephosphorylation of the phosphopeptides produces peptidic nanofibers for endosomal escape. Inhibiting TNAP, cleaving the membrane anchored TNAP, or disrupting lipid rafts abolishes the endocytosis. Decreasing the transformation to nanofibers prevents the endosomal escape. As the first study establishing a dynamic continuum of nanoscale assemblies for cellular uptake, this work illustrates an effective design for enzyme-responsive supramolecular therapeutics and provides mechanism insights for understanding the dynamics of cellular uptake of proteins or exogenous peptide aggregates.