[Objective] This study aimed to analyze tyrosinase activity and its expression in Varicorhinus macrolepis. [Method] V. macrolepis was used as experimental material for the analysis and research of tyrosinase in nine k...[Objective] This study aimed to analyze tyrosinase activity and its expression in Varicorhinus macrolepis. [Method] V. macrolepis was used as experimental material for the analysis and research of tyrosinase in nine kinds of organs and tissues of male and female V. macrolepis individuals by using polyacrylamide gel electrophoresis and biochemical staining method, spectrophotometry and enzyme histochemical technology. [Result] Tyrosinase exists in the liver and pancreas, intestine and spleen of female and male V. macrolepis and in the gallbladder of male V. macrolepis. Tyrosinase activities in various tissues of V. macrolepis varied largely. Specifically, tyrosinase activities in the spleen was the maximum, which was higher in female V. macrolepis than in males. According to the enzyme histochemistry results, strong positive signals of tyrosinase existed in the spleen, intestine, liver and pancreas and gallbladder of V. macrolepis, which was the strongest in the spleen. [Conclusion] In this paper, research on tissue localization of tyrosinase in V. macrolepis had been first reported, which provided theoretical basis for further exploring the functions of tyrosinase in V. macrolepis.展开更多
Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, p...Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.展开更多
The inhibiting effect of ciprofloxacin,norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol·L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement,electrochemica...The inhibiting effect of ciprofloxacin,norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol·L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement,electrochemical method,and X-ray photoelectron spectroscopy(XPS) .Effective inhibition was shown by mass loss,potentiodynamic polarization and impedance spectroscopy measurement.The corrosion rate of the metal in the mass loss measurement,and the corrosion reaction on cathode and anode in the electrochemical measurement were accelerated when temperature was increased.XPS results showed that the inhibitors adsorbed effectively on the metal surface.展开更多
Silver nanoparticles (Ag-NPs) were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic...Silver nanoparticles (Ag-NPs) were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic Force Microscope (AFM), was 91.57 nm. This reaserch effort proposes a mechanism for reducing the size of silver nanoparticles by adding the hydrogen peroxide (H202), and protecting the silver nanoparticle to inhibit agglomeration by adding PVP polymer.展开更多
Coal is one of the important energy sources, but it causes serious environmental problems such as air pollution, acid rain and greenhouse effects. Sulfur in coal is one of the responsibilities of these negative effect...Coal is one of the important energy sources, but it causes serious environmental problems such as air pollution, acid rain and greenhouse effects. Sulfur in coal is one of the responsibilities of these negative effects. Coal includes two types of sulfur: organic and inorganic. While inorganic sulfur can be completely removed with physical desulfurization methods, organic sulfur can be removed only by chemical desulfurization methods. But chemical methods are not only expensive but also difficult processes. Firstly in desulfurization, types of the sulfur content in coal should be well characterized. High sulfur Gediz-Turkey coal has been chosen to this study. This coal basin is located in the centre of the Turkey. In this study, characterization and desulfurization possibilities of high sulfur Gediz coal were investigated. For this purpose, several physical and chemical characterization methods such as proximate and ultimate coal analysis (ash, calorific value, volatile matter, moisture and sulfur analysis), mineralogical and petrographic analysis, fourier transform infrared spectroscopy, scanning electron microscope were used. Results of these analysis are shown that Gediz coals include 3.15% pyritic sulfur and 2.89% organic sulfur. Removing pyritic sulfur from Gediz-Turkey coal with physical methods such as gravity and sink-float separation is not possible because pyrite particle has 1-2 micron liberation size in coal.展开更多
Nanocomposites composed of one-dimensional(1D) CdS nanowires(NWs) and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties...Nanocomposites composed of one-dimensional(1D) CdS nanowires(NWs) and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties,photoelectrochemical(PEC) as well as photocatalytic activities for hydrogen evolution reaction(HER). Compared with pure CdS NWs, the optimized nanocomposite shows 5.5 times enhancement in photocurrent and 86.3 times increase for HER in the presence of glucose and lactic acid as hole scavengers.The enhanced PEC and HER activities are attributed to the intimate contact between MoS2 and CdS that efficiently enhances charge carrier separation. In addition, ultrafast transient absorption(TA) measurements have been used to probe the charge carrier dynamics and gain deeper insight into the mechanism behind the enhanced PEC and photocatalytic performance.展开更多
Femtoscience offers a unique way to understand the dynamics in physics, chemistry and biology. This subject focuses on the process happening at femto-to pico-second time scale by femtosecond optical methods. Widely us...Femtoscience offers a unique way to understand the dynamics in physics, chemistry and biology. This subject focuses on the process happening at femto-to pico-second time scale by femtosecond optical methods. Widely used in chemistry it reveals chemical reactions, including bond breaking, forming, and stretching, which happens at an ultrafast time scale. Femtoscience is also important in the biological system, for example, light harvesting system and vision system. Femtoscience in physics is also widely used, but it is not studied in this paper. Instead, we report new advances in femtochemistry and femtobiology, including structural dynamics, coherent control, enzyme function dynamics and hydration in the protein system. We also introduce attosecond science, focusing on electron dynamics at an extreme short time scale.展开更多
Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell na...Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell nanothorns (CSNTs) with rough and porous surfaces were synthesized for the first time through a facile co-chemical reduction method in the presence of polyallylamine hydrochloride (PAH) and ethylene glycol (EG) at room temperature. The size, morphology, and composition of Au@Pd CSNTs were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spec- troscopy (EDX), EDX mapping, and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of as-synthesized Au@Pd CSNTs were also studied by various electrochemical techniques. Au@Pd CSNTs exhibited remarkably high electrocatalytic activity and durability for the oxygen reduction reaction (ORR) in the alkaline media, owing to the unique porous structure and the synergistic effect between the Au core and Pd shell.展开更多
We have demonstrated a one-step and effective electrochemical method to synthesize graphene/MnO2 nanowall hybrids (GMHs). Graphene oxide (GO) was electrochemically reduced to graphene (GN), accompanied by the si...We have demonstrated a one-step and effective electrochemical method to synthesize graphene/MnO2 nanowall hybrids (GMHs). Graphene oxide (GO) was electrochemically reduced to graphene (GN), accompanied by the simultaneous formation of MnO2 with a nanowall morphology via cathodic electrochemical deposition. The morphology and structure of the GMHs were systematically characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The resulting GMHs combine the advantages of GN and the nanowall array morphology of MnO2 in providing a conductive network of amorphous nanocomposite, which shows good electrochemical capacitive behavior. This simple approach should find practical applications in the large-scale production of GMHs.展开更多
Water-soluble gelatin-PbS bionanocomposites (BNCs) were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy (TEM), X-ray diffrac...Water-soluble gelatin-PbS bionanocomposites (BNCs) were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis absorption spectra (UV-vis), Fourier transform infrared spectra (FT-IR) and circular dichroism (CD). FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2+ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures ([3-sheet, r-turn, or expanded). A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K (298/303/308 K: 3.11/2.00/1.60 × 10^6 tool/L) at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous (AG^θ 〈 0), and enthalpy-driven (△H^8 〈 0).展开更多
基金Supported by National Natural Science Foundation of China(3117207430700071)National Natural Science Foundation of Shandong Province(ZR2010CL002)~~
文摘[Objective] This study aimed to analyze tyrosinase activity and its expression in Varicorhinus macrolepis. [Method] V. macrolepis was used as experimental material for the analysis and research of tyrosinase in nine kinds of organs and tissues of male and female V. macrolepis individuals by using polyacrylamide gel electrophoresis and biochemical staining method, spectrophotometry and enzyme histochemical technology. [Result] Tyrosinase exists in the liver and pancreas, intestine and spleen of female and male V. macrolepis and in the gallbladder of male V. macrolepis. Tyrosinase activities in various tissues of V. macrolepis varied largely. Specifically, tyrosinase activities in the spleen was the maximum, which was higher in female V. macrolepis than in males. According to the enzyme histochemistry results, strong positive signals of tyrosinase existed in the spleen, intestine, liver and pancreas and gallbladder of V. macrolepis, which was the strongest in the spleen. [Conclusion] In this paper, research on tissue localization of tyrosinase in V. macrolepis had been first reported, which provided theoretical basis for further exploring the functions of tyrosinase in V. macrolepis.
基金Project(cstc2011jj A50008)supported by the Natural Science Foundation of Chongqing,ChinaProject(14ZB0025)supported by Education Department of Sichuan Province,China
文摘Zn-doped TiO2 (Zn?TiO2) thin films were prepared by the sol?gel method on titanium substrates with heat treatment at different temperatures. The effects of heat treatment temperatures and Zn doping on the structure, photocathodic protection and photoelectrochemical properties of TiO2 thin films were investigated. It is indicated that the photoelectrical performance of the Zn?TiO2 films is enhanced with the addition of Zn element compared with the pure-TiO2 film and the largest decline by 897 mV in the electrode potential is achieved under 300 °C heat treatment. SEM?EDS analyses show that Zn element is unevenly distributed in Zn?TiO2 films; XRD patterns reveal that the grain size of Zn?TiO2 is smaller than that of pure-TiO2; FTIR results indicate that Zn - O bond forms on Zn?TiO2 surface. Ultraviolet visible absorption spectra prove that Zn?TiO2 shifts to visible light region.Mott?Shottky curves show that the flat-band potential of Zn?TiO2 is more negative and charge carrier density is bigger than that ofpure-TiO2, implying that under the synergy of the width of the space-charge layer, carrier density and flat-band potential, Zn?TiO2 with 300 °C heat treatment displays the best photocathodic protection performance.
基金Supported by the National Science & Technology Pillar Program(082603101c) China Postdoctoral Science Foundation (O92623101H)+2 种基金 Shandong Postdoctoral Foundation(200902040) Open Project Program of Marine Corrosion and Protection Research Center of Institute of Oceanology Chinese Academy of Science(200901005) Doctor Foundation of University of Jinan(XBS0899)
文摘The inhibiting effect of ciprofloxacin,norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol·L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement,electrochemical method,and X-ray photoelectron spectroscopy(XPS) .Effective inhibition was shown by mass loss,potentiodynamic polarization and impedance spectroscopy measurement.The corrosion rate of the metal in the mass loss measurement,and the corrosion reaction on cathode and anode in the electrochemical measurement were accelerated when temperature was increased.XPS results showed that the inhibitors adsorbed effectively on the metal surface.
文摘Silver nanoparticles (Ag-NPs) were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic Force Microscope (AFM), was 91.57 nm. This reaserch effort proposes a mechanism for reducing the size of silver nanoparticles by adding the hydrogen peroxide (H202), and protecting the silver nanoparticle to inhibit agglomeration by adding PVP polymer.
文摘Coal is one of the important energy sources, but it causes serious environmental problems such as air pollution, acid rain and greenhouse effects. Sulfur in coal is one of the responsibilities of these negative effects. Coal includes two types of sulfur: organic and inorganic. While inorganic sulfur can be completely removed with physical desulfurization methods, organic sulfur can be removed only by chemical desulfurization methods. But chemical methods are not only expensive but also difficult processes. Firstly in desulfurization, types of the sulfur content in coal should be well characterized. High sulfur Gediz-Turkey coal has been chosen to this study. This coal basin is located in the centre of the Turkey. In this study, characterization and desulfurization possibilities of high sulfur Gediz coal were investigated. For this purpose, several physical and chemical characterization methods such as proximate and ultimate coal analysis (ash, calorific value, volatile matter, moisture and sulfur analysis), mineralogical and petrographic analysis, fourier transform infrared spectroscopy, scanning electron microscope were used. Results of these analysis are shown that Gediz coals include 3.15% pyritic sulfur and 2.89% organic sulfur. Removing pyritic sulfur from Gediz-Turkey coal with physical methods such as gravity and sink-float separation is not possible because pyrite particle has 1-2 micron liberation size in coal.
基金financially supported by the National Natural Science Foundation of China (51402126)support from Delta Dental Health Associates, NASA through MACES (NNX15AQ01A)UCSC Committee on Research Special Research Grant
文摘Nanocomposites composed of one-dimensional(1D) CdS nanowires(NWs) and 1 T-MoS2 nanosheets have been fabricated through a two-step solvothermal process. 5 mol% of MoS2 loading results in the best optical properties,photoelectrochemical(PEC) as well as photocatalytic activities for hydrogen evolution reaction(HER). Compared with pure CdS NWs, the optimized nanocomposite shows 5.5 times enhancement in photocurrent and 86.3 times increase for HER in the presence of glucose and lactic acid as hole scavengers.The enhanced PEC and HER activities are attributed to the intimate contact between MoS2 and CdS that efficiently enhances charge carrier separation. In addition, ultrafast transient absorption(TA) measurements have been used to probe the charge carrier dynamics and gain deeper insight into the mechanism behind the enhanced PEC and photocatalytic performance.
基金supported by the National Natural Science Foundation of China (Grant Nos.11074016,60878019,10821062,10934001 and 10828407)the National Basic Research Program of China (Grant No.2007CB307001)
文摘Femtoscience offers a unique way to understand the dynamics in physics, chemistry and biology. This subject focuses on the process happening at femto-to pico-second time scale by femtosecond optical methods. Widely used in chemistry it reveals chemical reactions, including bond breaking, forming, and stretching, which happens at an ultrafast time scale. Femtoscience is also important in the biological system, for example, light harvesting system and vision system. Femtoscience in physics is also widely used, but it is not studied in this paper. Instead, we report new advances in femtochemistry and femtobiology, including structural dynamics, coherent control, enzyme function dynamics and hydration in the protein system. We also introduce attosecond science, focusing on electron dynamics at an extreme short time scale.
文摘Bimetallic core-shell nanostructures with porous surfaces have drawn considerable attention due to their promising applications in various fields, including catalysis and electronics. In this work, Au@Pd core-shell nanothorns (CSNTs) with rough and porous surfaces were synthesized for the first time through a facile co-chemical reduction method in the presence of polyallylamine hydrochloride (PAH) and ethylene glycol (EG) at room temperature. The size, morphology, and composition of Au@Pd CSNTs were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spec- troscopy (EDX), EDX mapping, and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of as-synthesized Au@Pd CSNTs were also studied by various electrochemical techniques. Au@Pd CSNTs exhibited remarkably high electrocatalytic activity and durability for the oxygen reduction reaction (ORR) in the alkaline media, owing to the unique porous structure and the synergistic effect between the Au core and Pd shell.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Nos. 20935003 and 20820102037) and the 973 Project (No. 2010CB933603).
文摘We have demonstrated a one-step and effective electrochemical method to synthesize graphene/MnO2 nanowall hybrids (GMHs). Graphene oxide (GO) was electrochemically reduced to graphene (GN), accompanied by the simultaneous formation of MnO2 with a nanowall morphology via cathodic electrochemical deposition. The morphology and structure of the GMHs were systematically characterized by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The resulting GMHs combine the advantages of GN and the nanowall array morphology of MnO2 in providing a conductive network of amorphous nanocomposite, which shows good electrochemical capacitive behavior. This simple approach should find practical applications in the large-scale production of GMHs.
基金supported by the National Natural Science Foundation of China(21067001)Natural Science Foundation of Guangxi Province(0991083)Innovation Project of Guangxi University for Nationalities(gxun-chx2012091)
文摘Water-soluble gelatin-PbS bionanocomposites (BNCs) were synthesized via a facile one-pot chemical reaction method at pH 7.40. The samples were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis absorption spectra (UV-vis), Fourier transform infrared spectra (FT-IR) and circular dichroism (CD). FT-IR data were used to envis- age the binding of PbS particles with oxygen atoms of carbonyl groups of gelatin molecule. The possible integration mechanism between gelatin and PbS was discussed in detail. The effect of Pb2+ and PbS on the conformations of gelatin has also been analyzed by means of UV-vis, CD and FT-IR spectra, resulting in less c^-helix content and more open structures ([3-sheet, r-turn, or expanded). A new formula to calculate the association constant was proposed according to the relationship between the absorbance of gelatin-PbS BNCs and the free concentration of PbS, and apparent association constants K (298/303/308 K: 3.11/2.00/1.60 × 10^6 tool/L) at three different temperatures were calculated based on this formula. Thermodynamic parameters such as AG^θ, △Hθ and △S^θ were also determined. The results of the thermodynamic investigations indicated that the reaction was spontaneous (AG^θ 〈 0), and enthalpy-driven (△H^8 〈 0).