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The effects of the cell size and distribution on the mechanical properties of polypropylene foam were simulated and analyzed by finite element modeling with ANSYS and supporting experiments. The results show that the reduced cell size and narrow size distribution have beneficial influences on both the tensile and impact strengths. Decreasing the cell size or narrowing the cell size distribution was more effective for increasing the impact strength than the tensile strength in the same case. The relationship between the mechanical properties and cell structure parameters has a good correlation with the theoretical model.

The anisotropic carbon nanotubes (CNTs)/polycarbonate (PC)/polyethylene (PE) conductive polymer composite possesses a strong positive liquid coefficient (PLC), which can be attributed to the microfibrillar structure in the composite. A facile method, namely the isothermal treatment (IT), is proposed to manipulate the PLC of the CNTs/PC/PE composite. Different PLC intensities are achieved by controlling IT temperature and time. The PLC can even be eliminated when a proper IT temperature is chosen, exhibiting superb anti-solvent feature.

The purpose of this paper is to find the characteristic of entrepreneurial process for the student in free enterprise (SIFE) team in China, and to provide theoretical guidance for the entrepreneurial process of SIFE student team through a new Timmons model. Taking an entrepreneurial project of Shantou University SIFE team as example, a Timmons model was proposed describing the SIFE student team entrepreneurial process based on the famous entrepreneurial process model established by Jeffry A. Timmons. The application value of the new Timmons model was proved by case analysis. The paper summarized the main characteristics of the entrepreneurial model for the SIFE student team as: the nature of creation free enterprises, the excellent entrepreneurship networks, and the spirit of social entrepreneurship orientation. By case study, the paper proved the practical value of the new Timmons model by analysis of the key factors such as business opportunities, resources and entrepreneurial team, and their dynamic balance process. The new model proposed in the paper will have theoretical value to provide a direction for student entrepreneurial practice, the analysis of the characteristics of the new model will also enrich the research on entrepreneurship theory. This paper is the first research on SIFE student entrepreneurial process in China. In the past two years, the authors observed dozens of successful worldwide SIFE students' practical projects, but few of them appeared in the literature. It is hoped that this paper can offer some constructive advice to the entrepreneurial process of the SIFE student team and enrich the theory of general entrepreneurial education.

Aim： To investigate the roles of acetaldehyde dehydrogenase 2 （ALDH2）, the key enzyme of ethanol metabolism, in chronic low to moderate alcohol consumption-induced heart protective effects in mice. Methods： Twenty-one male wild-type （WT） or ALDH2-knockout （KO） mice were used in this study. In each genotype, 14 animals received alcohol （2.5%, 5% and 10% in week 1-3, respectively, and 18% in week 4-7）, and 7 received water for 7 weeks. After the treatments, survival rate and general characteristics of the animals were evaluated. Serum ethanol and acetaldehyde levels and blood lipids were measured. Metabolomics was used to characterize the heart and serum metabolism profiles. Results： Chronic alcohol intake decreased the survival rate of KO mice by 50%, and significantly decreased their body weight, but did not affect those of WT mice. Chronic alcohol intake significantly increased the serum ethanol levels in both WT and KO mice, but KO mice had significantly higher serum acetaldehyde levels than WT mice. Chronic alcohol intake significantly increased the serum HDL cholesterol levels in WT mice, and did not change the serum HDL cholesterol levels in KO mice. After chronic alcohol intake, WT and KO mice showed differential heart and serum metabolism profiles, including the 3 main energy substrate types （lipids, glucose and amino acids） and three carboxylic acid cycles. Conclusion： Low to moderate alcohol consumption increases HDL cholesterol levels and improves heart energy metabolism profile in WT mice but not in ALDH2-KO mice. Thus, preserved ALDH2 function is essential for the protective effect of low to moderate alcohol on the cardiovascular system.