How online food delivery platforms contributed to the resilience of the urban food system in China during the COVID-19 pandemic.

We use high-frequency data to quantify the nature and performance of online food delivery platforms during the COVID-19 pandemic in urban China, and to estimate the short- and long-term effects of lockdown and reopening measures. A staggered difference-in-differences (DID) estimation strategy and event study approach are used to identify the effects of lockdown and reopening measures on the performance of online food delivery platforms and restaurants. The results indicate that some restaurants continued to operate and offer online food delivery while lockdowns were in effect. Both the number of operating restaurants and their online food delivery services rebounded and experienced further growth after lockdowns were lifted. The adjustment path of the online food delivery business following the implementation of lockdowns differed from the adjustment path following the lifting of lockdowns. The lockdown and reopening measures did not affect all types of restaurant/cuisine equally. We also examine possible impact mechanisms of lockdown measures on online food delivery and restaurants, and conduct robustness checks to confirm the stability of the main findings. This study contributes to the existing literature by confirming the positive contribution of online food delivery to the resilience of urban food systems in response to unexpected external shocks. Our results have implications for the design of policies to guarantee food supply and help urban food systems adapt to unexpected shocks.

How online food delivery platforms contributed to the resilience of the urban food system in China during the COVID-19 pandemic

We use high-frequency data to quantify the nature and performance of online food delivery platforms during the COVID-19 pandemic in urban China, and to estimate the short- and long-term effects of lockdown and reopening measures. A staggered difference-in-differences (DID) estimation strategy and event study approach are used to identify the effects of lockdown and reopening measures on the performance of online food delivery platforms and restaurants. The results indicate that some restaurants continued to operate and offer online food delivery while lockdowns were in effect. Both the number of operating restaurants and their online food delivery services rebounded and experienced further growth after lockdowns were lifted. The adjustment path of the online food delivery business following the implementation of lockdowns differed from the adjustment path following the lifting of lockdowns. The lockdown and reopening measures did not affect all types of restaurant/cuisine equally. We also examine possible impact mechanisms of lockdown measures on online food delivery and restaurants, and conduct robustness checks to confirm the stability of the main findings. This study contributes to the existing literature by confirming the positive contribution of online food delivery to the resilience of urban food systems in response to unexpected external shocks. Our results have implications for the design of policies to guarantee food supply and help urban food systems adapt to unexpected shocks.

Contribution of CD4+ T cell-mediated inflammation to diarrhea in patients with COVID-19.

OBJECTIVES: This study aimed to explore the role of CD4+ T cells in the mechanisms of COVID-19 related diarrhea. METHODS: We analyzed lymphocyte subsets in patients with COVID-19 and the expression of angiotensin-converting enzyme 2 (ACE2), the transmembrane protease serine 2, and CD4+ T cell-related indicators in the colon were compared between patients with and without diarrhea. Correlation analyses were performed for ACE2 and other indicators to identify the relationship between SARS-CoV-2 infection and CD4+ mediated inflammation. The expression and distribution of CD4+ T cell-associated chemokines and their receptors were detected to determine the possibility of migration of CD4+ T cells to inflammation sites. RESULTS: The CD4+ T cell counts and percentages and CD4/CD8 ratio showed the most significant differences between the 2 groups. The diarrhea group expressed higher levels of ACE2, T-box expressed in T cells (Tbet), and tumor necrosis factor-alpha (TNFα) at both the mRNA and protein levels, with no difference from the nondiarrhea group for the percentage of ACE2+TNFα+ cells, indicating an indirect association between ACE2 and TNFα. The mRNA expression of CXCL10, CXCL11, and CXCR3 and the number of CD4+CXCR3+T cells were increased in the diarrhea group. CONCLUSIONS: CD4+ T cell-mediated inflammation may contribute to COVID-19 related diarrhea. CXCR3+ mediated migration of CD4+ T cells into the gut may perpetuate inflammation.

The Cytokine Profiles and Immune Response Are Increased in COVID-19 Patients with Type 2 Diabetes Mellitus.

The induction of inflammation and cytokine storm was proposed to play a critical role in COVID-19. This study is aimed at investigating the relationship between glucose metabolism and the inflammatory state of inpatients with COVID-19. 71 inpatients with COVID-19 were classified into nondiabetes mellitus (NDM) group, impaired fasting glucose (IFG) group, and diabetes mellitus (DM) group. The average hospitalization days were significantly shorter in DM patients when compared with patients in the IFG group and NDM group. CD4+ T cell percentage was higher while CD8+ T cells percentage was lower in the DM group than those in the NDM group. The serum levels of IL-6, IL-2, IL-10, and INF-γ in the DM group were upregulated when compared with those in the NDM group. The serum levels of TNF-α, IL-4, IL-2, IL-10, and INF-γ were significantly higher in the DM group than those in the IFG group. A significant difference was observed in CD4+ T cell, CD4+/CD8+ ratio percentage, IL-6, and IL-10 between the NDM group and DM group with adjusted BMI. In conclusion, COVID-19 patients with elevated glucose levels have promoted cytokine profiles and immune response.

The potential involvement of JAK-STAT signaling pathway in the COVID-19 infection assisted by ACE2.

COVID-19, a novel identified coronavirus disease due to Severe Acute Respiratory Syndrome coronaviruses 2 (SARS-Cov-2) infection, has posed a significant threat to public health worldwide. It has been reported COVID-19 keeps substantial nucleotide similarity and shares common receptor, Angiotensin-converting enzyme 2 (ACE2) with Severe Acute Respiratory Syndrome coronaviruses (SARS-Cov). Here, we investigated the gene expression of ACE2 and identified associated pathways of SARS-Cov as a useful reference for a deepening understanding of COVID-19. The results indicated the ACE2 was overexpressed in human airway epithelial cells (HAEs), especially at 72 h after SARS-Cov infection. We found ACE2 might regulate immune response through immunological activation-associated pathways in the process of in both SARS-Cov and SARS-Cov-2 infection, where the activation of B cells, macrophages, helper T cells 1 (Th1 cells) and the inhibition of Foxp3 + regulatory T (Treg) cells and CD8 + T cells were found to be prominent. Finally, significant correlation between ACE2 and JAK-STAT signaling pathway was identified which indicate that JAK-STAT signaling pathway might involve in the downstream action of the overactivation of ACE2. These findings are expected to gain a further insight into the action mechanism of COVID-19 infection and provide a promising target for designing effective therapeutic strategies.

Positive virus detection in patients who recovered from COVID-19 during quarantine period between discharge and home: a two-center experience in Wuhan, China.

The incidence of re-positive virus detection in patients who recovered from COVID-19 during quarantine was 6.2% in two designated locations, in Wuhan, indicating that suggestions for patients after discharge to be quarantined before leaving for home might be necessary. This experience might be referred to by other countries with epidemic outbreak.