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This paper provides the first causal evidence that hostile activities online lead to physical violence. Given the recently documented relationship between pollution and social media, I exploit exogenous variation in local air quality as the first step to instrument for online aggression. In an event study setting, I find volatile organic compounds (VOCs) increase by 7% when refineries experience unexpected production outages. Together with higher air pollution, I find more aggressive behaviors both online and offline, as well as worse health outcomes near refineries. A one standard deviation increase in surrounding VOCs leads to 0.16 more hate crimes against Black people and 0.23 more hospital visits per thousand people each day. Second, I consider how emotional contagion spreads through social networks. On days with pollution spikes, surrounding areas see 30% more offensive and racist tweets and 12% more crimes; those geographically distant but socially networked regions also see offensive and racist tweets increase by 3% and more crimes by 4.5%. Nationally, overlooking spillovers would underestimate crime effects of pollution by 24%. My findings highlight the consequences of social media hostility and contribute to the public debate on cyberspace regulation.

Since the outbreak of the coronavirus disease (COVID-19) pandemic, governments around the globe have undertaken multiple policies to control its spread. Yet, only a few studies estimated the cost of COVID-19-related stringency measures on economic output, which can be attributable to the time lag and low frequency of conventional economic data. To bridge this gap in the literature, this paper uses novel high-frequency and spatially granular surface urban heat island (SUHI) data from satellites to quantify the impact of COVID-19-related containment policies in the People's Republic of China, exploiting variations in such policies. Three empirical results emerge. First, we find stringency measures decrease urban heat island in locked cities only marginally, which is equivalent to 0.04-0.05 standard deviation or CNY22.2 billion ($3.6 billion) of economic output drop which is a 0.09% annual gross domestic product decline in 2020. Second, our results suggest that governments have been learning continuously to manage containment measures better. Third, the government's containment policies have generated both positive and negative spillover effects on unlocked cities in which the former effect has dominated the latter.

Toll-like receptor 2 (TLR2) is a bridge between innate immunity and adaptive immunity. TLR2 agonists have been exploited as potential vaccine adjuvants and antitumor agents. However, no TLR2 agonists have been approved by FDA up to now. To discover drug-like TLR2 selective agonists, a novel series of Pam3CSK4 derivatives were designed based on the crystal structure of hTLR2-hTLR1-Pam3CSK4 complex, synthesized and evaluated for their immune-stimulatory activities. Among them, 35c was identified as a murine-specific TLR2 agonist, while 35f was a human-specific TLR2 agonist. Besides, 35d (human and murine TLR2 agonist) showed TLR2 agonistic activity comparable to Pam3CSK4, which included: elevated IL-6 expression level (EC50 = 83.08 ± 5.94 nM), up-regulated TNF-α and IL-6 mRNA expression and promoted maturation of DCs through activating the NF-κB signaling pathway. TLRs antibodies test showed that 35a and 35d were TLR2/1 agonists, while 35f was a TLR2/6 agonist.