Synchrotron X-ray diffraction study for crystal structure of solid carbon dioxide CO2-V
Synchrotron X-ray diffraction study for solid CO2 at 40?100 GPa and around 2,000 K has shown that the diffraction pattern of the high pressure phase CO2-V is consistently interpreted in terms of a tetragonal uni_t cell (Z = 4, a = 3.584 ?, c = 5.908 ? at 50GPa). A ?-cristobalite structure (space group I2d) gives a good account of our data qualitatively. Isothermal molar volume (300K) of the CO2-V in the present study is smaller than that indexed as a tridymite structure proposed by previous studies at any pressures.
Eukaryotic small interfering RNAs (siRNA) expression vector specific for Cyclooxygenase-2 (COX-2) was constructed and transfected into gastric adenocarcinoma cell line AGS. The expression of COX-2 and the phosphorylation of AKT were detected by Western-blot. The results showed that the expression of COX-2 was inhibited in COX-2 siRNA stable transfectants compare with empty vector transfectants, and the AKT phosphorylation at Ser473 and Thr308 was also inhibited by COX-2 siRNA. These findings provide new insights into the roles of COX-2 in gastric carcinogenesis and possible targets for chemoprevention.