With the development of science and technology, buying has become much easier. At the same time, however, impulsive buying has many negative consequences for college students, and the causes of impulsive buying should therefore be explored. To explore the relationship between social exclusion and impulsive buying and its underlying mechanism, this study used the Social Exclusion Scale, Self-Esteem Scale, Risk Preference Scale, and Impulsive Buying Scale to investigate the roles of self-esteem and risk preference in the relationship between social exclusion and impulsive buying among 768 college students (387 were female, Mage = 20.25 years). The results were as follows: (1) when controlling for gender, age, family monthly income, and monthly living expenses, social exclusion significantly and positively predicted impulsive buying; (2) self-esteem played a mediating role between social exclusion and impulsive buying; (3) risk preference moderated the relationship between the second half of the mediating path and the direct path. These results reveal the mechanism underlying impulsive buying in college students, that is, social exclusion will predict the decrease of college students' self-esteem, and low self-esteem will further predict college students' impulsive buying which is a way for them to gain a sense of self-worth. Relatively low risk preference can well alleviate the negative impact of social exclusion and low self-esteem on impulsive buying. What’s more, these results have implications for impulsive buying interventions. Schools should aim to create a good peer atmosphere by making certain rules that help to reduce social exclusion and parents and education departments should cultivate students’ risk awareness to avoid risk behaviors in college students, such as impulsive buying behavior.

Based on screening in computational biology and biological in vitro assays, five natural products isolated from extracts of the herbal medicine toad skin, such as cinobufagin (CBFi), bufalin (BFi), arenobufagin (ABFi), telocinobufagin (TBFi), bufotalin (BFTi), were subjected to molecular docking calculations with the use of SARS-CoV-2 main protease (PDB 6LU7 and 7BTF) and top-scoring ligand-receptor complexes were obtained. The results showed that the binding energy of ABFi to the 3CL protein was -17.044kcal/mol, which was higher than CBFi and TBFi. However, the binding energy of ABFi to the RdRp protease was -23.250 kcal/mol, which was much lower than that of CBFi and TBFi, EVEN lower than that of ABFi to the 3CL protein. ABFi also has polar interactions with amino acids such as Glu811, Ser814, Ser681 and Thr680 of RdRp enzyme. The results revealed that ABFi had a moderate inhibitory effect on the cell proliferation of SARS-CoV-2 in vitro, with an inhibition rate of 61.12%, even weaker than Remdesivir. This new discovery provides us with new ideas for in-depth studies on the development of natural products with this class of structural generalizations as inhibitors of SARS-CoV-2, and provides an experimental basis for the next step of mechanistic studies.