Search

It was recently shown that ZnO nanoparticles (NPs) could induce endoplasmic reticulum (ER) stress in human umbilical vein endothelial cells (HUVECs). If ER stress is associated the toxicity of ZnO NPs, the presence of ER stress inducer thapsigargin (TG) should alter the response of HUVECs to ZnO NP exposure. In this study, we addressed this issue by assessing cytotoxicity, oxidative stress and inflammatory responses in ZnO NP exposed HUVECs with or without the presence of TG. Moreover, TiO2NPs were used to compare the effects. Exposure to 32 μg/mL ZnO NPs (p < 0.05), but not TiO2NPs (p > 0.05), significantly induced cytotoxicity as assessed by WST-1 and neutral red uptake assay, as well as intracellular ROS. ZnO NPs dose-dependently increased the accumulation of intracellular Zn ions, and ZnSO4induced similar cytotoxic effects as ZnO NPs, which indicated a role of Zn ions. The release of inflammatory proteins tumor necrosis factor α (TNFα) and interleukin-6 (IL-6) or the adhesion of THP-1 monocytes to HUVECs was not significantly affected by ZnO or TiO2NP exposure (p > 0.05). The presence of 250 nM TG significantly induced cytotoxicity, release of IL-6 and THP-1 monocyte adhesion (p < 0.01), but did not significantly affect intracellular ROS or release of TNFα (p > 0.05). ANOVA analysis indicated no interaction between exposure to ZnO NPs and the presence of TG on almost all the endpoints (p > 0.05) except neutral red uptake assay (p < 0.01). We concluded ER stress is probably not associated with ZnO NP exposure induced oxidative stress and inflammatory responses in HUVECs. [ABSTRACT FROM PUBLISHER]

Abstract: Pd–Fe–Ox catalysts for low temperature CO oxidation were supported on SBA-15, CeO2 nano-particles with rich (111) facets and CeO2 nano-rod with rich (200) facets, and characterized by X-ray diffraction, low-temperature nitrogen adsorption, transmission electron microscopy and temperature-programmed reduction. The results showed that when CeO2 nano-rod was used as a support, Pd–Fe–Ox catalyst exhibits higher activity (T 100 =10°C), resulting from the rich (200) facets of CeO2 nano-rod, which leads to a formation of large numbers of the oxygen vacancies on the surface of Pd–Fe–Ox catalysts. [Copyright &y& Elsevier]

Abstract: The Pd–Cu–Cl x /Al2O3 catalysts were prepared by an NH3 coordination-impregnation (CI) method in water and organic solvents, and exhibited much higher activity for CO oxidation than the catalyst prepared by conventional wet impregnation (WI) method. Their chemical and physical properties were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results show that in the process of preparing the catalysts by CI, different solvents affect obviously their catalytic performance and isopropanol is the most suitable solvent among water, ethanol, acetone and isopropanol. The CO oxidation over Pd–Cu–Cl x /Al2O3 catalyst (CI) can be accelerated remarkably with an increase of H2O concentration in the reactant gas, and it is weakly dependent on the CO and O2 concentrations. Compared with the catalyst prepared by WI, the catalyst prepared by CI possesses the higher dispersion and lower-temperature reducibility of copper phase, much more active Cu2+ species, and easier re-oxidation of Cu+. The Pd+ active site on the catalyst (CI) is more active than Pd2+ on the catalyst (WI), and the rate-determining step is the re-oxidation of Pd0 to Pd+ by Cu2+ on the catalyst (CI) instead of the re-oxidation of Cu+ to Cu2+ by O2 on the catalyst (WI). [Copyright &y& Elsevier]

Pd–Cu–Clx/Al2O3catalysts were prepared by a NH3coordination-impregnation method and exhibited an excellent activity for low-temperature CO oxidation and 100% CO conversion was obtained at −30 °C for 400 ppm CO and 1000 ppm H2O/air. [ABSTRACT FROM AUTHOR]