In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were...In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, inductively coupled plasma atomic emission spectrometer （ICP-AES）, temperature programmed reduction （H2-TPR）, CO chemisorption, energy dispersive X-ray （EDX） and scanning electron microscopy （SEM） techniques. Kinetic properties of all catalysts were investigated in a batch re- actor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/AlzO3 catalyst enhances its activity as compared to Fe/AlaO3. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/AlzO3 catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fez（MoO4）3 phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fez（MoO4）3 phase has low reducibility, therefore the Fe2（MoO4）3 phase significantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al2O3 catalyst. Overall, this study introduces Fe-Mo/Al2O3 as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.展开更多
Gadolinium has been widely used as a contrast agent for magnetic resonance imaging in clinical practice. Recently, it was reported that gadolinium is involved in nephrogenic systemic fibrosis, although the exact mecha...Gadolinium has been widely used as a contrast agent for magnetic resonance imaging in clinical practice. Recently, it was reported that gadolinium is involved in nephrogenic systemic fibrosis, although the exact mechanism by which gadolinium triggers nephrogenic systemic fibrosis remains unclear. In this study, we show that gadolinium chloride （GdC13） induced human umbilical vein endothelial cells （HUVECs） to migrate in Matrigel and tubulogenesis during wound healing. Chick chorioallantoic membrane assay confirmed that GdC13 stimulates angiogenesis. Under the optimal angiogenic concentration of GdC13 （1 0 ~tM）, intracellular calcium concentration and reactive oxygen species generation were elevated. Moreover, western blotting results indicate that in cells treated with GdC13, Ca2＋-dependent PKCa/132 was phosphorylated, and MAPKs pathways were also activated. Taken together, GdC13 has a potential effect on angiogenesis in HUVECs, and the possible mechanisms may involve oxidative stress and calcium-related signalin~ pathways.展开更多
基金Supported by the Iranian Nano Technology Initiative Council and Petroleum University of Technology
文摘In reverse water gas shift （RWGS） reaction COa is converted to CO which in turn can be used to pro- duce beneficial chemicals such as methanol. In the present study, Mo/AlaO3, Fe/AlaO3 and Fe-Mo/Al2O3 catalysts were synthesised using impregnation method. The structures of catalysts were studied using X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET） method, inductively coupled plasma atomic emission spectrometer （ICP-AES）, temperature programmed reduction （H2-TPR）, CO chemisorption, energy dispersive X-ray （EDX） and scanning electron microscopy （SEM） techniques. Kinetic properties of all catalysts were investigated in a batch re- actor for RWGS reaction. The results indicated that Mo existence in structure of Fe-Mo/AlzO3 catalyst enhances its activity as compared to Fe/AlaO3. This enhancement is probably due to better Fe dispersion and smaller particle size of Fe species. Stability test of Fe-Mo/AlzO3 catalyst was carried out in a fixed bed reactor and a high CO yield for 60 h of time on stream was demonstrated. Fez（MoO4）3 phase was found in the structures of fresh and used catalysts. TPR results also indicate that Fez（MoO4）3 phase has low reducibility, therefore the Fe2（MoO4）3 phase significantly inhibits the reduction of the remaining Fe oxides in the catalyst, resulted in high stability of Fe-Mo/Al2O3 catalyst. Overall, this study introduces Fe-Mo/Al2O3 as a novel catalyst with high CO yield, almost no by-products and fairly stable for RWGS reaction.
基金National Natural Science Foundation of China(Grant No.20637010)
文摘Gadolinium has been widely used as a contrast agent for magnetic resonance imaging in clinical practice. Recently, it was reported that gadolinium is involved in nephrogenic systemic fibrosis, although the exact mechanism by which gadolinium triggers nephrogenic systemic fibrosis remains unclear. In this study, we show that gadolinium chloride （GdC13） induced human umbilical vein endothelial cells （HUVECs） to migrate in Matrigel and tubulogenesis during wound healing. Chick chorioallantoic membrane assay confirmed that GdC13 stimulates angiogenesis. Under the optimal angiogenic concentration of GdC13 （1 0 ~tM）, intracellular calcium concentration and reactive oxygen species generation were elevated. Moreover, western blotting results indicate that in cells treated with GdC13, Ca2＋-dependent PKCa/132 was phosphorylated, and MAPKs pathways were also activated. Taken together, GdC13 has a potential effect on angiogenesis in HUVECs, and the possible mechanisms may involve oxidative stress and calcium-related signalin~ pathways.
