Takeo Nakano

Local structures of Ni species were evaluated in the NiO/γ-Al2O3 catalyst prepared via impregnation method for dimethyl sulfide (DMS) decomposition. Calcination and sulfurization conditions of the prepared catalyst influenced by the catalytic activity for DMS decomposition. The decomposition performance increased with sulfurization by H2S compared to sulfurization with DMS prior to the reaction test. X-ray diffraction and X-ray photoelectron spectroscopy analyses suggested that the active sites are NiS. In-situ X-ray absorption spectroscopy analysis was performed to examine the fine structural changes in Ni species before and after the sulfurization treatment. At 500°C calcination of the catalyst, Ni species were present as NiO and NiAl24 at a ration of 4:6 and only NiO was sulfurized to NiS which acted as the active sites. Meanwhile, for the catalyst calcined at 800°C, Ni species were nearly completely present as the Ni component in the NiAl2O4 structure, which was less susceptible to sulfurization than NiO. This result implied that the NiS amount in the catalyst calcined at 800°C was greatly reduced, resulting in lower decomposition activity.

Human embryonic kidney 293T (HEK293T) cells are used in various biological experiments and researches. In this study, we investigated the effect of cell culture environments on morphological and functional properties of HEK293T cells. We used several kinds of dishes made of polystyrene or glass for cell culture, including three types of polystyrene dishes provided from different manufacturers for suspension and adherent cell culture. In addition, we also investigated the effect of culturing on gelatin-coated surfaces on the cell morphology. We found that HEK293T cells aggregated and formed into three-dimensional (3-D) multicellular spheroids (MCS) when non-coated polystyrene dishes were used for suspension culture. In particular, the non-coated polystyrene dish from Sumitomo bakelite is the most remarkable characteristic for 3-D MCS among the polystyrene dishes. On the other hand, HEK293T cells hardly aggregated and formed 3-D MCS on gelatin-coated polystyrene dishes for suspension culture. HEK293T cells adhered on the non- or gelatin-coated polystyrene dish for adherent culture, but they did not form 3-D MCS. HEK293T cells also adhered to non- or gelatin-coated glass dishes and did not form 3-D MCS in serum-free medium. These results suggest that HEK293T cells cultured on non-coated polystyrene dish may be useful for the tool to analyze the characteristics of 3D-MCS.