The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0....The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.展开更多
A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvi...A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvinylpyrrolidone（PVP） on the morphology and electrochemical performance of the composite were investigated. Powder X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and nitrogen adsorption-desorption experiment were employed to characterize the microstructures and morphologies of the composite. Meanwhile, the electrochemical performances of the samples were studied using cyclic voltammetry（CV）, galvanostatic charge-discharge test and electrochemical impedance spectroscopy（EIS）. The results show that the porous Co3O4/Cu O-CTAB nanoplates own the best performance and exhibits a high specific capacitance of 398 F/g at 1 A/g with almost 100% capacitance retention over 2000 cycles, and it retains 90% of capacitance at 10 A/g.展开更多
AIM:To study the action of aminoguanidine on pancreatic cancer xenografts in relation to cell proliferation,apoptosis,redox status and vascularization.METHODS:Xenografts of PANC-1 cells were developed in nude mice. Th...AIM:To study the action of aminoguanidine on pancreatic cancer xenografts in relation to cell proliferation,apoptosis,redox status and vascularization.METHODS:Xenografts of PANC-1 cells were developed in nude mice. The animals were separated into two groups:control and aminoguanidine treated. Tumor growth,survival and appearance of metastases were determined in vivo in both groups. Tumors were excised and ex vivo histochemical studies were performed. Cell growth was assessed by Ki-67 expression. Apoptosis was studied by intratumoral expression of B cell lymphoma-2 protein (Bcl-2) family proteins and Terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (Tunel). Redox status was evaluated by the expression of endothelial nitric oxide synthase (eNOS),catalase,copper-zinc superoxide dismutase (CuZnSOD),manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPx). Finally,vascularization was determined by Massons trichromic staining,and by VEGF and CD34 expression.RESULTS:Tumor volumes after 32 d of treatment by aminoguanidine (AG) were significantly lower than in control mice (P < 0.01). Median survival of AG mice was significantly greater than control animals (P < 0.01). The appearance of both homolateral and contralateral palpable metastases was significantly delayed in AG group. Apoptotic cells,intratumoral vascularization (trichromic stain) and the expression of Ki-67,Bax,eNOS,CD34,VEGF,catalase,CuZnSOD and MnSOD were diminished in AG treated mice (P < 0.01),while the expression of Bcl-2 and GPx did not change.CONCLUSION:The antitumoral action of aminoguanidine is associated with decreased cell proliferation,reduced angiogenesis,and reduced expression of antioxidant enzymes.展开更多
At room temperature, the reaction of dibenzoyl peroxide with metallic copper powder in the presence of pyridine affords the copper(Ⅱ) complex [Cu(C 5H 5N) 2(H 2O)\|(C 6H 5COO) 2]. Crystal is monoclinic, M r =483.002,...At room temperature, the reaction of dibenzoyl peroxide with metallic copper powder in the presence of pyridine affords the copper(Ⅱ) complex [Cu(C 5H 5N) 2(H 2O)\|(C 6H 5COO) 2]. Crystal is monoclinic, M r =483.002, space group Cc with parameters: a=6\^078(4), b=15.879(4), c=23.091(3), β=97.61(2)°, V=2209.1(2) 3, Z=4, D c =1\^464g/cm 3, μ =10.279 cm -1 , F(000)=996, R=0\^031, R w =0.036, 1595 reflections with I≥3σ(I ) were considered to be observed. Each copper(Ⅱ) ion is coordinated by two monodentate benzoate ligands, two pyridines and one water molecule. The complex is also characterized by its IR, XPS and thermal properties.展开更多
We conducted two-stage acidification-bioleaching experiments to probe the feasibility of bioleaching for a kind of mixed alkaline copper oxide and sulphide mineral. We used the uniform design method for data analysis ...We conducted two-stage acidification-bioleaching experiments to probe the feasibility of bioleaching for a kind of mixed alkaline copper oxide and sulphide mineral. We used the uniform design method for data analysis and experimental optimization, with initial pH value, pulp density, inoculation of bacteria and ferrous iron concentration selected as the influential factors. Polynomial regression shows that the four factors sequentially influence the copper recovery by 14.430%, 8.555%, 1.982% and 3.895%. Acid equilibrium in the bioleaching system is mainly influenced by alkaline gangue content, chemical reactions and bacterial activity. A maximal portion of refractory copper extracted reaches 71.08%. The dynamic analysis of copper recovery indicates that bioleaching goes through a lag leaching phase, prime leaching phase and leaching stationary phase corresponding to the growth phases of bacteria. Compared with the predicted value of 80.87%, the confirmatory experiment observes a 78.21% copper recovery under the optimal conditions of pH of 1.5, pulp density of 5%, bacteria inoculation of 30% and initial ferrous iron concentration of 9 g L-1. Results suggest that bioleaching is technically feasible to improving total copper recovery.展开更多
The design and preparation of suitable supports are of great importance for gold catalysts to attain excellent catalytic performance for alcohol oxidation.In this work,we found that ZnO-CuO mixed oxides supported gold...The design and preparation of suitable supports are of great importance for gold catalysts to attain excellent catalytic performance for alcohol oxidation.In this work,we found that ZnO-CuO mixed oxides supported gold catalysts showed much better catalytic activity for base-free aerobic oxidation of benzyl alcohol than Au/ZnO and Au/CuO catalysts,and among them Au/Zn0.7Cu0.3O displayed the best catalytic performance.In addition,the Au/Zn0.7Cu0.3O catalyst could selectively catalyze the aerobic oxidation of a wide range of alcohols to produce the corresponding carbonyl compounds with high yields under mild conditions without base.Further characterizations indicated that the outstanding catalytic performance of Au/Zn0.7Cu0.3O was correlated with the small size of Au nanoparticles(NPs),good low-temperature reducibility,high concentration of surface oxygen species,and collaborative interaction between Au NPs and mixed oxide.展开更多
A kinetic study on the sulfuric acid leaching of multi-metal oxide, which is the product of multi-metal copper alloy with iron trioxide roasted in oxygen, was carried out. The effects of leaching time, stirring speed,...A kinetic study on the sulfuric acid leaching of multi-metal oxide, which is the product of multi-metal copper alloy with iron trioxide roasted in oxygen, was carried out. The effects of leaching time, stirring speed, sulfuric acid concentration, reaction temperature, and particle size of the multi-metal oxide on the kinetics and mechanism of copper extraction were studied. It was found that the reaction kinetic model about the copper extraction from multi-metal oxide follows the mixed kinetic shrinking core mode： 1/31n（1-X）＋（1-X）-l/3-1=680.5C（H2SO4）0.4297dp0.75115exp（-Ea/RT）t.展开更多
基金supported by the National Natural Science Foundation of China(21173100 and 21320102001)~~
文摘The catalytic epoxidation of olefin was investigated on two copper complex-modified molybdenum oxides with a 3D supramolecular structure, [Cu（bipy）]4[Mo15O47].2H2O （1） and [Cu1（bix）][（Cu1bix） （δ-MoVl8O26）0.5] （2） （bipy = 4,4＇-bipyridine, bix = 1,4-bis（imidazole-1-ylmethyl）benzene）. Both compounds were catalytically active and stable for the epoxidation of cyclooctene, 1-octene, and styrene with tert-butyl hydroperoxide （t-BuOOH） as oxidant. The excellent catalytic performance was attributed to the presence of stable coordination bonds between the molybdenum oxide and copper complex, which resulted in the formation of easily accessible Mo species with high electropositivity. In addition, the copper complex also acted as an active site for the activation of t-BuOOH, thus im- proving these copper complex-modified polyoxometalates.
基金Project(21471162)supported by the National Natural Science Foundation of ChinaProject(2014LY36)supported by the Science and Technology Project of Longyan CityChina
文摘A promising Co3O4/Cu O composite electrode material was successfully synthesized through a facile hydrothermal and calcination process. Effects of the surfactants hexadecyltrimethyl ammonium bromide（CTAB） and polyvinylpyrrolidone（PVP） on the morphology and electrochemical performance of the composite were investigated. Powder X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and nitrogen adsorption-desorption experiment were employed to characterize the microstructures and morphologies of the composite. Meanwhile, the electrochemical performances of the samples were studied using cyclic voltammetry（CV）, galvanostatic charge-discharge test and electrochemical impedance spectroscopy（EIS）. The results show that the porous Co3O4/Cu O-CTAB nanoplates own the best performance and exhibits a high specific capacitance of 398 F/g at 1 A/g with almost 100% capacitance retention over 2000 cycles, and it retains 90% of capacitance at 10 A/g.
基金Supported by Grants from University of Buenos Aires (B098 and B112)
文摘AIM:To study the action of aminoguanidine on pancreatic cancer xenografts in relation to cell proliferation,apoptosis,redox status and vascularization.METHODS:Xenografts of PANC-1 cells were developed in nude mice. The animals were separated into two groups:control and aminoguanidine treated. Tumor growth,survival and appearance of metastases were determined in vivo in both groups. Tumors were excised and ex vivo histochemical studies were performed. Cell growth was assessed by Ki-67 expression. Apoptosis was studied by intratumoral expression of B cell lymphoma-2 protein (Bcl-2) family proteins and Terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (Tunel). Redox status was evaluated by the expression of endothelial nitric oxide synthase (eNOS),catalase,copper-zinc superoxide dismutase (CuZnSOD),manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPx). Finally,vascularization was determined by Massons trichromic staining,and by VEGF and CD34 expression.RESULTS:Tumor volumes after 32 d of treatment by aminoguanidine (AG) were significantly lower than in control mice (P < 0.01). Median survival of AG mice was significantly greater than control animals (P < 0.01). The appearance of both homolateral and contralateral palpable metastases was significantly delayed in AG group. Apoptotic cells,intratumoral vascularization (trichromic stain) and the expression of Ki-67,Bax,eNOS,CD34,VEGF,catalase,CuZnSOD and MnSOD were diminished in AG treated mice (P < 0.01),while the expression of Bcl-2 and GPx did not change.CONCLUSION:The antitumoral action of aminoguanidine is associated with decreased cell proliferation,reduced angiogenesis,and reduced expression of antioxidant enzymes.
文摘At room temperature, the reaction of dibenzoyl peroxide with metallic copper powder in the presence of pyridine affords the copper(Ⅱ) complex [Cu(C 5H 5N) 2(H 2O)\|(C 6H 5COO) 2]. Crystal is monoclinic, M r =483.002, space group Cc with parameters: a=6\^078(4), b=15.879(4), c=23.091(3), β=97.61(2)°, V=2209.1(2) 3, Z=4, D c =1\^464g/cm 3, μ =10.279 cm -1 , F(000)=996, R=0\^031, R w =0.036, 1595 reflections with I≥3σ(I ) were considered to be observed. Each copper(Ⅱ) ion is coordinated by two monodentate benzoate ligands, two pyridines and one water molecule. The complex is also characterized by its IR, XPS and thermal properties.
基金Funded by the National Natural Science Foundation of China (No. 50934002)New Century Excellent Talents (No. NECT-07-0070)Yunnan Provincial Programs for Science and Technology Innovation (No. 2007AD001)
文摘We conducted two-stage acidification-bioleaching experiments to probe the feasibility of bioleaching for a kind of mixed alkaline copper oxide and sulphide mineral. We used the uniform design method for data analysis and experimental optimization, with initial pH value, pulp density, inoculation of bacteria and ferrous iron concentration selected as the influential factors. Polynomial regression shows that the four factors sequentially influence the copper recovery by 14.430%, 8.555%, 1.982% and 3.895%. Acid equilibrium in the bioleaching system is mainly influenced by alkaline gangue content, chemical reactions and bacterial activity. A maximal portion of refractory copper extracted reaches 71.08%. The dynamic analysis of copper recovery indicates that bioleaching goes through a lag leaching phase, prime leaching phase and leaching stationary phase corresponding to the growth phases of bacteria. Compared with the predicted value of 80.87%, the confirmatory experiment observes a 78.21% copper recovery under the optimal conditions of pH of 1.5, pulp density of 5%, bacteria inoculation of 30% and initial ferrous iron concentration of 9 g L-1. Results suggest that bioleaching is technically feasible to improving total copper recovery.
基金supported by the National Natural Science Foundation of China(21606219)the “Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21030900)~~
文摘The design and preparation of suitable supports are of great importance for gold catalysts to attain excellent catalytic performance for alcohol oxidation.In this work,we found that ZnO-CuO mixed oxides supported gold catalysts showed much better catalytic activity for base-free aerobic oxidation of benzyl alcohol than Au/ZnO and Au/CuO catalysts,and among them Au/Zn0.7Cu0.3O displayed the best catalytic performance.In addition,the Au/Zn0.7Cu0.3O catalyst could selectively catalyze the aerobic oxidation of a wide range of alcohols to produce the corresponding carbonyl compounds with high yields under mild conditions without base.Further characterizations indicated that the outstanding catalytic performance of Au/Zn0.7Cu0.3O was correlated with the small size of Au nanoparticles(NPs),good low-temperature reducibility,high concentration of surface oxygen species,and collaborative interaction between Au NPs and mixed oxide.
基金Project(2011AA061003)supported by Hi-Tech Research and Development Program of China
文摘A kinetic study on the sulfuric acid leaching of multi-metal oxide, which is the product of multi-metal copper alloy with iron trioxide roasted in oxygen, was carried out. The effects of leaching time, stirring speed, sulfuric acid concentration, reaction temperature, and particle size of the multi-metal oxide on the kinetics and mechanism of copper extraction were studied. It was found that the reaction kinetic model about the copper extraction from multi-metal oxide follows the mixed kinetic shrinking core mode： 1/31n（1-X）＋（1-X）-l/3-1=680.5C（H2SO4）0.4297dp0.75115exp（-Ea/RT）t.
