Objective The goal of this study is to know the level of radon in greenbelt soil in Chengdu city. Methods 152 monitoring sites were selected in the riverside, roadside, park, campus and residential area in Chengdu city. Concentration of radon in the soil was determined with KJD-2000R radon detector. Results Although the level of radon in the central area was higher than those in the peripheral area the level of radon in the riverside was higher than that in the parks, the mean level of radon investigated in this study (14 047 Bq/m3) was lower than the national mean level(7 300 Bq/m3). Conclusion It can be considered that the level of radon in the greenbelt soil in Chengdu city is in the normal range.

BACKGROUND: Both hydroxyapatite (HA) and large diameter TiO2 nanotubes have excellent biocompatibility, but bone-forming ability of nano-HA (nHA) deposited large diameter TiO2 nanotubes is rarely reported.OBJECTIVE: To evaluate the bone-forming ability of nHA/large-diameter TiO2 nanotube composite coating.METHODS: Large-diameter TiO2 nanotubes were prepared by anodic oxidation method, and then nHA was electrochemically deposited on the surface of TiO2 nanotubes. Preosteoblasts MC3T3-E1 were co-cultured with the nHA/large diameter TiO2 nanotube composite, pure titanium and TiO2 nanotube coatings, respectively. At 0.5, 1, 2 hours after culture, the initial cell adhesion was observed. At 1, 3, 5 day after culture, cell proliferation was assessed. At 2 days after culture, cell morphology was observed. At 3 and 7 days after osteogenic induction, intracellular alkaline phosphatase activity was detected. At 14 days after osteogenic induction, mineralization of extracellular matrix was detected.RESULTS AND CONCLUSION: (1) After 2 hours of culture, the number of adherent cells on the composite coating was significantly lower than that on the TiO2 nanotube coating (P < 0.05), but slightly higher than that on the pure titanium coating with no statistical difference. (2) After 1, 3, 5 days of culture, the cell proliferation on the composite coating was significantly lower than that on the TiO2 nanotube coating (P < 0.05), but slightly higher than that on the pure titanium with no statistical difference. (3) The cells on the pure titanium showed a spindle-shape, while those on the TiO2 nanotube coating processed filopodia. The cells on the composite coating showed polygonal shape with a larger number of filopodia. (4) The intracellular alkaline phosphatase activity of the composite coating group was significantly higher than that of the pure titanium group and TiO2 nanotube group. The trend of mineralization of extracellular matrix was ranked from high to low: the composite coating group > TiO2 nanotube group > pure titanium group. To conclude, the nHA/large diameter TiO2 nanotube composite coating not only has good biocompatibility, but also has the ideal ability to promote bone formation.

Cell Cycle Proteins ; Microtubule-Associated Proteins