A semi-empirical method to estimate the surface tension of molten alloys at different oxygen partialpressures is suggested in this study. The surface tension of molten Ag-Sn and Ag-Cu alloys were calculatedusing the Butler equation with the surface tension value of pure substance at a given oxygen partialpressure. The oxygen partial pressure ranges were 2.86×10-12－1.24×10-9Pa for the Ag-Sn system and2.27×10-11－5.68×10-4 Pa for the Ag-Cu system. In this calculation, the interactions of the adsorbed oxygenwith other metallic constituents were ignored. The calculated results of the Ag-Sn alloys were in reasonableaccordance with the experimental data within a difference of 8%. For the Ag-Cu alloy system at a higheroxygen partial pressure, the surface tension initially decreased but showed a minimum at XAg = 0.05 to increaseas the silver content increased. This behavior appears to be related to the oxygen adsorption and thecorresponding surface segregation of the constituent with a lower surface tension. Nevertheless, the calculatedresults of the Ag-Cu alloys with the present model were in good agreement with the experimental data withina difference of 10%.

The objective of this study was to investigate the effects of oxygen tension during in vitro maturation of porcine oocytes on the nuclear maturation and differences in gene expression. Cumulus-oocyte complexes (COCs) were collected from ovaries obtained at a local slaughterhouse, matured for 44 hours in TCM199 supplemented with porcine follicular fluid (pFF) under 5% or 20% oxygen concentration. In results, oxygen tension had no significant effects on nuclear maturation. Relative poly(A) mRNA abundance of MnSOD, CCNB1, LDHA, G6PD, BCL, GPX1, IGFR2, GLUT1, BAX, GREM, PTGS2 was analysed in cumulus cells. GLUT1, G6PD, LDHA were up-regulated in the cumulus cells matured in low oxygen, suggesting a higher glucose uptake and an increase in anaerobic glycolysis, whereas CCNB, MnSOD were up-regulated in the cumulus cells matured in high oxygen, which suggest a higher activity of mitosis-promoting factor and antioxidant response. In conclusion, cumulus cells increase in glucose metabolism via anaerobic glycolysis under low oxygen concentration and show significant change in antioxidant against oxidant damage or apoptotic response under high oxygen concentration. For such an effect of cumulus cells, oocytes could be matured normally regardless of various oxygen concentration.