Damage points induced by 355 nm laser irradiation increase more quickly on the surface of fused silica in vacuum of about 10^-3 Pa than in atmospheric air at the same fluence. The larger concentration of point defects...Damage points induced by 355 nm laser irradiation increase more quickly on the surface of fused silica in vacuum of about 10^-3 Pa than in atmospheric air at the same fluence. The larger concentration of point defects in vacuum is confirmed by photoluminescence intensity. X-ray photoelectron spectroscopy and infrared absorption indicate the formation of sub-stoichiometric silica on the surface. The degradation mechanism of fused silica in vacuum is discussed.展开更多
文摘目的：利用Hoechst33342/PI双染法和原位末端标记法（TUNEL染色检测纳米二氧化硅（nm-SiO2）对神经细胞凋亡的影响，比较两种检测方法的优缺点。方法：以体外培养的人神经母细胞瘤SK-N-SH为研究对象，15和30 nm粒径的nm-SiO2（剂量为2.5、5、10μg/mL）分别处理细胞24 h，另设1-5 m SiO2组和溶剂对照组，采用Hoechst33342/PI双染法和TUNEL染色检测各处理组对SK-N-SH细胞凋亡的影响。结果：与对照组相比，两种检测方法分析均显示了nm-SiO2处理组SK-N-SH细胞凋亡率显著增加（P〈0.05），且具有尺寸、剂量依赖性，而微米级SiO2对凋亡的影响不显著（P〉0.05）。结论：nm-SiO2能诱导SK-N-SH细胞凋亡。Hoechst33342/PI双染法特异性高，简单易行；TUNEL法灵敏度高，能检测少量的细胞凋亡，但成本较高，两种方法可结合使用以便更加准确的检测神经细胞的凋亡。
文摘Damage points induced by 355 nm laser irradiation increase more quickly on the surface of fused silica in vacuum of about 10^-3 Pa than in atmospheric air at the same fluence. The larger concentration of point defects in vacuum is confirmed by photoluminescence intensity. X-ray photoelectron spectroscopy and infrared absorption indicate the formation of sub-stoichiometric silica on the surface. The degradation mechanism of fused silica in vacuum is discussed.
