An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar ...An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.展开更多
Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively....Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.展开更多
That the photosensitive action of hematoporphyrin can damage tumor cells, has attracted much attention recently. However, its mechanism of action is not very clear. Some reported that the damage is due to the producti...That the photosensitive action of hematoporphyrin can damage tumor cells, has attracted much attention recently. However, its mechanism of action is not very clear. Some reported that the damage is due to the production of singlet oxygen （1O2）, a cy-展开更多
Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ...Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ·OH, namely how the radical induces a cell to die, are poorly understood. The present work highlights the changes of the energy/redox status during apoptosis by exogenous ·OH treatment. HeLa cells were induced to undergo typical apoptosis by ·OH generated directly via the Fe 2+ mediated Fenton reaction. The thermodynamics study indicated that the ·OH treatment increased the cellular heat output in the first hours, and then the cellular thermodynamics shifted to endothermic. The data demonstrates that the mitochondria are actively involved in ·OH treatment induced apoptosis, with the cellular oxygen consumption rapidly decreasing after the ·OH treatment for only 0.5 h. But DNA fragmentation, which is the major characteristic of apoptosis, took place 16 h after ·OH treatment. The results suggest that alteration of the energy/redox metabolism and the energy/redox status may be the primary causes among the early events of ·OH induced apoptosis.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11272338)the Science and Technology on Scramjet Key Laboratory Funding,China(Grant No.STSKFKT 2013004)the China Scholarship Council
文摘An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence（LIF）methods is developed to quantitatively measure the concentrations of hydroxyl in CH;/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor.
文摘Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.
文摘That the photosensitive action of hematoporphyrin can damage tumor cells, has attracted much attention recently. However, its mechanism of action is not very clear. Some reported that the damage is due to the production of singlet oxygen （1O2）, a cy-
文摘Reactive oxygen species (ROS), including the hydroxyl radical ( · OH), are known to be potential modulators of apoptosis. However, the biochemical mechanisms underlying apoptosis induced by ·OH, namely how the radical induces a cell to die, are poorly understood. The present work highlights the changes of the energy/redox status during apoptosis by exogenous ·OH treatment. HeLa cells were induced to undergo typical apoptosis by ·OH generated directly via the Fe 2+ mediated Fenton reaction. The thermodynamics study indicated that the ·OH treatment increased the cellular heat output in the first hours, and then the cellular thermodynamics shifted to endothermic. The data demonstrates that the mitochondria are actively involved in ·OH treatment induced apoptosis, with the cellular oxygen consumption rapidly decreasing after the ·OH treatment for only 0.5 h. But DNA fragmentation, which is the major characteristic of apoptosis, took place 16 h after ·OH treatment. The results suggest that alteration of the energy/redox metabolism and the energy/redox status may be the primary causes among the early events of ·OH induced apoptosis.
