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Objective. To investigate VIP effect on the cytotoxicity of NK cell to gastric cancer cells in vitro and the relation between the effect with the NKG2D signal molecules in NK cells. Material and Methods. NK cells were purified from peripheral blood mononuclear cells (PBMC). Before and after NK cells were incubated with VIP or its antagonist (D-p-Cl-Phe6,Leu17)-VIP, we detected the cytotoxicity of NK cells to MKN45 gastric cancer cells by MTT and detected the expressions of NKG2D, DAP10, and NF-κB proteins and mRNAs in NK cells by immunocytochemistry and RT-PCR in those conditions. Then we analyzed the effect of VIP and its antagonist on the cytotocicity of NK cell to gastric cancer cells and on expressions of NKG2D, DAP10, and NF-κB signal molecules in NK cells. Results. VIP could inhibit the cytotoxicity of NK cells to MKN45 cells and could inhibit the expressions of NKG2D, DAP10, and NF-κB in NK cells. However, (D-p-Cl-Phe6, Leu17)-VIP could reverse those effects. Conclusions. The VIP inhibited the cytotoxicity of NK cell to MKN45 cells which might get through inhibiting the expressions of NKG2D signal molecules in NK cells. This may be one mechanism of gastric cancer cells escaping organism immune clearance.

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By analyzing the data of China's stock return from 2001 to 2021, this paper uses the five factor model to study the impact of disposal effect on the excess return of portfolio based on reversal strategy, so as to judge whether the disposal effect is one of the driving factors of reversal effect in China's stock market, and constructs the disposal factor based on the five factor model. Compared with the stock markets of developed countries, the momentum effect in China's stock market is weak and the reversal effect is strong. This paper finds that there is a significant reversal effect in China's stock market in the past two decades. Due to the majority of retail investors in China's stock market, the disposal effect of investors is very common, and it can affect the excess return of portfolio under the reversal strategy.

Because the number of the fuzzy sets in input and output variable fields directly affects the completeness of fuzzy rules and decides the performance of control system, an approach optimizing fuzzy sets based on hierarchical genetic algorithms is proposed in this paper, which optimizes the number and shape of fuzzy sets in fields currently, makes fuzzy sets distribution orderly and reduces the rule's redundancy. The simulation results of second ordered system show that the approach presented in this paper is effective.