Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic＂ effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercu...Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic＂ effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde （MDA）, superoxide dismutase （SOD）, GSH-peroxidase （GSH-px） and Glutathione （GSH） in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-los mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction （RT-PCR） and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-los mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group （P〈0.01）. It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes （IEGs）; free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.展开更多
Strain-compensated Ge/Si0.15Ge0.85 multiple quantum wells were grown on an Si0.1 Ge0.9 virtual substrate using ultrahigh vacuum chemical vapor deposition technology on an n＋-Si（001） substrate. Photoluminescence mea...Strain-compensated Ge/Si0.15Ge0.85 multiple quantum wells were grown on an Si0.1 Ge0.9 virtual substrate using ultrahigh vacuum chemical vapor deposition technology on an n＋-Si（001） substrate. Photoluminescence measurements were performed at room temperature, and the quantum confinement effect of the direct-bandgap transitions of a Ge quantum well was observed, which is in good agreement with the calculated results. The luminescence mechanism was discussed by recombination rate analysis and the temperature dependence of the luminescence spectrum.展开更多
Ge-on-Si p-i-n diodes are fabricated by using two-step Ge film epitaxial technology on Si substrates.A remarkable Franz-Keldysh effect is observed in the wavelength range of 1620-1640nm with a largestΔα/αof 2.8 at ...Ge-on-Si p-i-n diodes are fabricated by using two-step Ge film epitaxial technology on Si substrates.A remarkable Franz-Keldysh effect is observed in the wavelength range of 1620-1640nm with a largestΔα/αof 2.8 at 1640nm by optical responsivity measurement.The remarkable change of absorption coefficient in the considerable large wavelength range makes Ge-on-silicon a promising candidate for Si-based electro-absorption modulators.The initial design predicts a modulator of bandwidth~50 GHz,and the extinction ratio>7dB by the measured parameter.展开更多
文摘Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic＂ effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde （MDA）, superoxide dismutase （SOD）, GSH-peroxidase （GSH-px） and Glutathione （GSH） in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-los mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction （RT-PCR） and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-los mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group （P〈0.01）. It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes （IEGs）; free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61036003,61176013,61177038,and 60906035)the High Technology Research and Development Program of China(Grant No.2011AA010302)
文摘Strain-compensated Ge/Si0.15Ge0.85 multiple quantum wells were grown on an Si0.1 Ge0.9 virtual substrate using ultrahigh vacuum chemical vapor deposition technology on an n＋-Si（001） substrate. Photoluminescence measurements were performed at room temperature, and the quantum confinement effect of the direct-bandgap transitions of a Ge quantum well was observed, which is in good agreement with the calculated results. The luminescence mechanism was discussed by recombination rate analysis and the temperature dependence of the luminescence spectrum.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61036003,61176013,60906035and 61177038,the National High-Technology and Research Development Program of China under Grant No 2011AA010302the Tsinghua National Laboratory for Information Science and Technology(TNList)Cross-discipline Foundation.
文摘Ge-on-Si p-i-n diodes are fabricated by using two-step Ge film epitaxial technology on Si substrates.A remarkable Franz-Keldysh effect is observed in the wavelength range of 1620-1640nm with a largestΔα/αof 2.8 at 1640nm by optical responsivity measurement.The remarkable change of absorption coefficient in the considerable large wavelength range makes Ge-on-silicon a promising candidate for Si-based electro-absorption modulators.The initial design predicts a modulator of bandwidth~50 GHz,and the extinction ratio>7dB by the measured parameter.
