Insight into core -shell microporous zinc silicate adsorbent to eliminate antibiotics in aquatic environment under the COVID-19 pandemic.

Under the new crown pneumonia (COVID-19) epidemic, the intensive use of therapeutic drugs has caused certain hidden danger to the safety of the water environment. Therefore, the core-shell microporous zinc silicate (SiO2@ZSO) was successfully prepared and used for the adsorption of chloroquine phosphate (CQ), tetracycline (TC) and ciprofloxacin (CIP) for eliminating the threat of COVID-19. The adsorption efficiencies of 20 mg L-1 of CQ, TC and CIP by SiO2@ZSO were all up to 60% after 5 min. The adsorption capacity of SiO2@ZSO for CQ, TC and CIP can reach 49.01 mg g-1, 56.06 mg g-1 and 104.77 mg g-1, respectively. The adsorption process is primarily physical adsorption, which is heterogeneous, spontaneous and preferential. Moreover, the effects of temperature, pH, salinity, and reusability on the adsorption of CQ, TC, and CIP on SiO2@ZSO were investigated. The adsorption mechanism mainly involves electrostatic attraction, partitioning and hydrogen bonding, which is insightful through the changes of the elements and functional groups before and after adsorption. This work provides a solution to the problems faced by the treatment of pharmaceuticals wastewater under the COVID-19 epidemic.

The Configuration of Incentives in Small and Medium-Sized Content Platform Enterprises Under the Normalization of COVID-19.

The COVID-19 pandemic has made the advantages of online knowledge communities with cross-space, time, interpersonal, and other characteristics fully demonstrated. Exploring the configurations of platform incentives to improve knowledge collaboration performance can provide a reference for the efficient and sustainable development of the platforms under the normalization of the COVID-19 pandemic. With the help of the fuzzy set qualitative comparative analysis method, taking the social Q&A platform enterprises as an example, this study analyzed the configurations of platform incentives for the high knowledge collaborative performance from the dimensions of market incentives and social incentives, and the heterogeneity of knowledge capital appreciation and social capital appreciation is also discussed. The results show that each of the platform incentives (virtual currency, cash benefit, community reputation, social identity, skill training, and communication) does not constitute a necessary condition for high performance. There are four and three types of configurations for intellectual capital appreciation and social capital appreciation, respectively. The important findings are that nearly 30% of users may participate in knowledge production based on pure economic benefits, and there may be so-called "get the best deal" behavior. Social identity, community reputation, and skill training have an important incentive effect on knowledge collaboration. Communication supplemented by a little economic incentives can significantly promote the appreciation of social capital.

Clinical and immunological characteristics in COVID-19 convalescent patients.

The humoral and cellular immunity of convalescent COVID-19 patients is involved in pathogenesis and vaccine immunity. In this study, through CoV-psV neutralization assay and IFN-γ ELISpot testing in 30 cases of COVID-19 patients after 9 months post-SARS-CoV-2 infection, it found that the ratio of memory/naive CD4+ T lymphocytes cells and levels of anti-SARS-CoV-2-IgM and RBD-IgM were slightly but significantly higher in COVID-19 severe convalescent patients than that in non-severe patients. The specific cellular and humoral immunity against SARS-CoV-2 were detectable, regardless of the severity of the disease in the acute phase. This information may help understanding the immune status after SARS-CoV-2 infection.

Selenium-atom-modified thymidine enhances the specificity and sensitivity of DNA polymerization and detection.

Nucleobase mismatches can jeopardize DNA polymerization specificity, causing mutations and errors in DNA replication and detection. Herein we report the first synthesis of novel 2-Se-thymidine triphosphate (SeTTP), describe the single-selenium atom-specific modification strategy (SAM) against T/G mismatches, and demonstrate SAM-assisted polymerization and detection with much higher specificity and sensitivity. SAM can effectively suppress the formation of non-specific products in DNA polymerization and detection. Thus, SAM enhances the specificity of DNA synthesis by approximately 10 000 fold, and in turn, it allows the detection of clinical COVID-19 viral RNA in low copy numbers (single-digit copies), while the conventional RT-qPCR does not.

Establishment of a Financial Crisis Early Warning System for Domestic Listed Companies Based on Three Decision Tree Models

The financial crisis is a realistic problem that the general enterprise must encounter in the process of financial management. Due to the impact of the COVID-19 and the Sino-US trade war, domestic companies with unsound financial conditions are at risk of shutdowns and bankruptcies. Therefore, it is urgently needed to study the financial warning of enterprises. In this study, three decision tree models are used to establish the financial crisis early warning system. These three decision tree models include C50, CART, and random forest decision trees. In addition, the ROC curve was used for comprehensive evaluation of the accuracy analysis of the model to confirm the predictive ability of each model. This result can provide reference for domestic financial departments and provide financial management basis for the investing public.