Adsorption of single gold （Au） atom at three kinds of sites （hollow, bridge and top） on the hydroxylated β-cristobalite SiO2 （1 1 1） surface was studied using the first-principles calculations with general grad...Adsorption of single gold （Au） atom at three kinds of sites （hollow, bridge and top） on the hydroxylated β-cristobalite SiO2 （1 1 1） surface was studied using the first-principles calculations with general gradient approximation （GGA）. The results of adsorption energies and density of electronic states （DOS） suggest that the hollow and bridge sites have the basically equal capability of binding Au, while the ability of the Top site is weaker. Two new energy levels emerge after the adsorption at all sites; in DOS of the Hollow configuration, one locates at -0.15 eV, composed of Au 5d and O 2p electronic states, another just crosses through the Fermi level, consisting of Au 6s, H 1s and O 2p. In addition, Mulliken population analyses indicate that electron transfer takes place between the Au atom and the surface H and O atoms in the Hollow and Bridge configurations, which can be used to interpret the adsorption of Au onto the positions. However, neither H nor O chemically bonds with Au atom.展开更多
The scavenging effect of berbamine（Ber） on active oxygen radicals was studied, using a spin-trapping technique and a chemiluminescence（CL） method in phorbol myristate acetate（PMA） stimulated polymorphonuclear le...The scavenging effect of berbamine（Ber） on active oxygen radicals was studied, using a spin-trapping technique and a chemiluminescence（CL） method in phorbol myristate acetate（PMA） stimulated polymorphonuclear leukocytes（PMN） and in four cell-free superoxide（O<sub>2</sub>） or hydroxyl radical（OH） generating systems. Ber（0.1 to 0.3 mM） effectively reduced active oxygen radicals in PMN stimulated with PMA, but had no obvious effect on oxygen consumption during the respiratory burst of PMN, measured with spin probe oxymetry. Ber（0.3 mM） prominently inhibited the CL response of展开更多
基金Funded by the Fundamental Research Funds for the Central Universities (No. CUGL100240)
文摘Adsorption of single gold （Au） atom at three kinds of sites （hollow, bridge and top） on the hydroxylated β-cristobalite SiO2 （1 1 1） surface was studied using the first-principles calculations with general gradient approximation （GGA）. The results of adsorption energies and density of electronic states （DOS） suggest that the hollow and bridge sites have the basically equal capability of binding Au, while the ability of the Top site is weaker. Two new energy levels emerge after the adsorption at all sites; in DOS of the Hollow configuration, one locates at -0.15 eV, composed of Au 5d and O 2p electronic states, another just crosses through the Fermi level, consisting of Au 6s, H 1s and O 2p. In addition, Mulliken population analyses indicate that electron transfer takes place between the Au atom and the surface H and O atoms in the Hollow and Bridge configurations, which can be used to interpret the adsorption of Au onto the positions. However, neither H nor O chemically bonds with Au atom.
文摘The scavenging effect of berbamine（Ber） on active oxygen radicals was studied, using a spin-trapping technique and a chemiluminescence（CL） method in phorbol myristate acetate（PMA） stimulated polymorphonuclear leukocytes（PMN） and in four cell-free superoxide（O<sub>2</sub>） or hydroxyl radical（OH） generating systems. Ber（0.1 to 0.3 mM） effectively reduced active oxygen radicals in PMN stimulated with PMA, but had no obvious effect on oxygen consumption during the respiratory burst of PMN, measured with spin probe oxymetry. Ber（0.3 mM） prominently inhibited the CL response of
