CO2 selective reduction to CO with H2 over a CeO2-supported nano-Au catalyst at atmospheric pres- sure was investigated. A high CO2 conversion, approaching the thermodynamic equilibrium value, and nearly 100% CO selec...CO2 selective reduction to CO with H2 over a CeO2-supported nano-Au catalyst at atmospheric pres- sure was investigated. A high CO2 conversion, approaching the thermodynamic equilibrium value, and nearly 100% CO selectivity were obtained. The surface formate intermediates generated during the reverse water-gas shift reaction at 400 ℃ were identified using in situ diffuse-reflectance infra- red Fourier-transform spectroscopy. The formate consumption to give CO and H20, determined using mass spectrometry, indicated that the reaction proceeded via an associative formate mecha- nism; this contributes to the high Au/CeO2 catalytic activity at low temperatures.展开更多
The roles of intermediate conductance Ca2＋-activated K＋ channel （IKCal） in the pathogene- sis of hepatocellular carcinoma （HCC） were investigated. Immunohistochemistry and Western blotting were used to detect th...The roles of intermediate conductance Ca2＋-activated K＋ channel （IKCal） in the pathogene- sis of hepatocellular carcinoma （HCC） were investigated. Immunohistochemistry and Western blotting were used to detect the expression of IKCal protein in 50 HCC and 20 para-carcinoma tissue samples. Real-time PCR was used to detect the transcription level of IKCal mRNA in 13 HCC and 11 para-carcinoma tissue samples. The MTT assay was used to measure the function of IKCal in human HCC cell line HepG2 in vitro. TRAM-34, a specific blocker of IKCal, was used to intervene with the function of IKCal. As compared with para-carcinoma tissue, an over-expression of IKCal protein was detected in HCC tissue samples （P〈0.05）. The mRNA expression level of IKCal in HCC tissues was 2.17 times higher than that in para-carcinoma tissues. The proliferation of HepG2 cells was suppressed by TRAM-34 （0.5, 1.0, 2.0 and 4.0 pxnol/L） in vitro （P〈0.05）. Our results suggested that IKCal may play a role in the proliferation of human HCC, and IKCal blockers may represent a potential therapeutic strategy for HCC.展开更多
This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated thro...This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated through an innovative strategy involving Sn electrodeposition,oxidation,and MnO_(2)-layer preparation.The structure of the anode was characterized,and the oxygen evolution performance was evaluated in a H_(2)SO_(4) solution.The results show that compared with the Ti/SnO_(2)/MnO_(2) anode prepared by the conventional brushing-annealing process,the Ti/SnO_(x)/MnO_(2) anode fabricated through the innovative procedure exhibits a lower oxygen evolution potential and a nearly 40%longer accelerated lifespan.The superior oxygen evolution performance of the Ti/SnO_(x)/MnO_(2) anode is attributed to the distinctive SnO_(x) intermediate layer fabricated through Sn electrodeposition followed by oxidation,which indicates the great potential of the anode as a dimensionally stable anode for metal electrowinning and hydrogen production by electrolysis,etc.展开更多
（S）-2-aminobutyric acid being initial raw material,（S）-2-hydroxybutyric acid methyl ester was synthesized by means of a three step reaction of hydroxylation, salification and esterification. The product had a yiel...（S）-2-aminobutyric acid being initial raw material,（S）-2-hydroxybutyric acid methyl ester was synthesized by means of a three step reaction of hydroxylation, salification and esterification. The product had a yield rate of 60.4%, purity of 99% and ee value higher than 99% by characterization of GC, HPLC and 1H NMR. This synthesis technique has advantages of high purity and ee value, low cost, short reaction time and mild reaction conditions so that it is suitable for production on industrial scale.展开更多
CO_(2)fixation is important for reducing the greenhouse effect and improving clean energy use.While recent studies focus on converting CO_(2)to liquid fuels,direct fixation into high-value compounds like aromatic carb...CO_(2)fixation is important for reducing the greenhouse effect and improving clean energy use.While recent studies focus on converting CO_(2)to liquid fuels,direct fixation into high-value compounds like aromatic carboxylic acids provides an alternative path.Herein,we report a general electrochemical CO_(2)fixation to aromatic carboxylic acids via the CO_(2)^(·-)intermediate using a non-transition metal graphite electrode.Different from the conventional aromatic radical mechanism,in this report,CO_(2)will gain electrons on the graphite electrode to generate CO_(2)^(·-),which will further attack aromatic halides to obtain the desired aromatic carboxylic acid via an aromatic nucleophilic substitution mechanism.As CO_(2)^(·-)acts as the general intermediate,various aromatic compounds can be carbonylated without the need for a specific catalytic design to activate the aromatic halides.Furthermore,benefit from the CO_(2)^(·-)nucleophile,only the ipso-products can be obtained compared with the conventional approaches.This method offers a flexible way to convert the greenhouse gas CO_(2)into valuable aromatic carboxylic acids,which have applications in pharmaceutical chemistry,biochemistry and polymer chemistry.Therefore,it holds the potential for furthering the objectives of carbon neutrality and green chemistry.展开更多
Antimony selenide(Sb_(2)Se_(3))is a potential photovoltaic(PV)material for next-generation solar cells and has achieved great development in the last several years.The properties of Sb_(2)Se_(3)absorber and back conta...Antimony selenide(Sb_(2)Se_(3))is a potential photovoltaic(PV)material for next-generation solar cells and has achieved great development in the last several years.The properties of Sb_(2)Se_(3)absorber and back contact influence the PV performances of Sb_(2)Se_(3)solar cells.Hence,optimization of back contact characteristics and absorber orientation are crucial steps in raising the power conversion efficiency(PCE)of Sb_(2)Se_(3)solar cells.In this work,MoO2was introduced as an intermediate layer(IL)in Sb_(2)Se_(3)solar cells,and comparative investigations were conducted.The growth of(211)-oriented Sb_(2)Se_(3)with large grains was facilitated by introducing the MoO2IL with suitable thickness.The MoO2IL substantially lowered the back contact barrier and prevented the formation of voids at the back contact,which reduced the thickness of the MoSe2interface layer,inhibited carrier recombination,and minimized bulk and interfacial defects in devices.Subsequently,significant optimization enhanced the open-circuit voltage(VOC)of solar cells from 0.481 V to 0.487 V,short-circuit current density(JSC)from 23.81 m A/cm^(2)to 29.29 m A/cm^(2),and fill factor from 50.28%to 57.10%,which boosted the PCE from 5.75%to 8.14%.展开更多
Isolation of RuⅢ-bda(17-electron specie)complex with an aqua ligand(2-electron donor)is challenging due to violation of the 18-electron rule.Although considerable efforts have been dedicated to mechanistic studies of...Isolation of RuⅢ-bda(17-electron specie)complex with an aqua ligand(2-electron donor)is challenging due to violation of the 18-electron rule.Although considerable efforts have been dedicated to mechanistic studies of water oxidation by the Ru-bda family,the structure and initial formation of the Ru^(Ⅲ)-bda aqua complex are still controversial.Herein,we challenge this often overlooked step by designing a pocketshape Ru-based complex 1.The computational studies showed that 1 possesses the crucial hydrophobicity at the Ru^(V)(O)state as well as similar probability of access of terminal O to solvent water molecules when compared with classic Ru-bda catalysts.Through characterization of single-crystal structures at the Ru^(Ⅱ) and Ru^(Ⅲ) states,a pseudo seven-coordinate“ready-togo”aqua ligand with Ru^(Ⅲ)…O distance of 3.62A was observed.This aqua ligand was also found to be part of a formed hydrogen-bonding network,providing a good indication of how the Ru^(Ⅲ)-OH_(2)complex is formed.展开更多
Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This st...Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This study reports a novel dual‐site Co‐Zn catalyst designed to enhance the hydrazine oxidation reaction(HzOR)activity.Density functional theory calculations suggested that incorporating Zn into Co catalysts can weaken the binding strength of the crucial N_(2)H_(3)*intermediate,which limits the ratedetermining N_(2)H_(3)*desorption step.The synthesized p‐Co_(9)Zn1 catalyst exhibited a remarkably low reaction potential of−0.15 V versus RHE at 10mAcm−2,outperforming monometallic Co catalysts.Experimental and computational analyses revealed dual active sites at the Co/ZnO interface,which facilitate N_(2)H_(3)*desorption and subsequent N_(2)H_(2)*formation.A liquidN_(2)H_(4)‐H_(2)O_(2)fuel cell with p‐Co_(9)Zn1 catalyst achieved a high open circuit voltage of 1.916 V and a maximum power density of 195mWcm^(−2),demonstrating the potential application of the dual‐site Co‐Zn catalyst.This rational design strategy of tuning the N_(2)H_(3)*binding energy through bimetallic interactions provides a pathway for developing efficient and economical non‐precious metal electrocatalysts for DHzHPFCs.展开更多
Oocyte production in most mammalian species is believed to cease before birth.However,this idea has been challenged with the finding that postnatal mouse ovaries possess mitotically active germ cells.A recent study sh...Oocyte production in most mammalian species is believed to cease before birth.However,this idea has been challenged with the finding that postnatal mouse ovaries possess mitotically active germ cells.A recent study showed that female germline stem cells(FGSCs)from adult mice were isolated,cultured long term and produced oocytes and progeny after transplantation into infertile mice.Here,we demonstrate the successful generation of transgenic or gene knock-down mice using FGSCs.The FGSCs from ovaries of 5-day-old and adult mice were isolated and either infected with recombinant viruses carrying green fluorescent protein,Oocyte-G1 or the mouse dynein axonemal intermediate chain 2 gene,or transfected with the Oocyte-G1 specific shRNA expression vector(pRS shOocyte-G1 vector),and then transplanted into infertile mice.Transplanted cells in the ovaries underwent oogenesis and produced heterozygous offspring after mating with wild-type male mice.The offspring were genetically characterized and the biological functions of the transferred or knock-down genes were investigated.Efficiency of genetransfer or gene knock-down was 29%–37%and it took 2 months to produce transgenic offspring.Gene manipulation of FGSCs is a rapid and efficient method of animal transgenesis and may serve as a powerful tool for biomedical science and biotechnology.展开更多
Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in t...Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.展开更多
基金supported by the National Natural Science Foundation of China (11475041, 11175036, 21373037)the Fundamental Research Funds for the Central Universities (DUT16QY49)~~
文摘CO2 selective reduction to CO with H2 over a CeO2-supported nano-Au catalyst at atmospheric pres- sure was investigated. A high CO2 conversion, approaching the thermodynamic equilibrium value, and nearly 100% CO selectivity were obtained. The surface formate intermediates generated during the reverse water-gas shift reaction at 400 ℃ were identified using in situ diffuse-reflectance infra- red Fourier-transform spectroscopy. The formate consumption to give CO and H20, determined using mass spectrometry, indicated that the reaction proceeded via an associative formate mecha- nism; this contributes to the high Au/CeO2 catalytic activity at low temperatures.
基金supported by grants from the National Natural Science Foundation of China (No. 81072001)the Natural Science Foundation of Hubei Province, China (No.2011CDB556)
文摘The roles of intermediate conductance Ca2＋-activated K＋ channel （IKCal） in the pathogene- sis of hepatocellular carcinoma （HCC） were investigated. Immunohistochemistry and Western blotting were used to detect the expression of IKCal protein in 50 HCC and 20 para-carcinoma tissue samples. Real-time PCR was used to detect the transcription level of IKCal mRNA in 13 HCC and 11 para-carcinoma tissue samples. The MTT assay was used to measure the function of IKCal in human HCC cell line HepG2 in vitro. TRAM-34, a specific blocker of IKCal, was used to intervene with the function of IKCal. As compared with para-carcinoma tissue, an over-expression of IKCal protein was detected in HCC tissue samples （P〈0.05）. The mRNA expression level of IKCal in HCC tissues was 2.17 times higher than that in para-carcinoma tissues. The proliferation of HepG2 cells was suppressed by TRAM-34 （0.5, 1.0, 2.0 and 4.0 pxnol/L） in vitro （P〈0.05）. Our results suggested that IKCal may play a role in the proliferation of human HCC, and IKCal blockers may represent a potential therapeutic strategy for HCC.
文摘The photochemical[2+2]cycloaddition reaction of carbonyl compunds and alkenes was studied by photochemical induced dynamic nuclear spin polarization.
文摘This work is devoted to the development of a low cost dimensionally stable anode with high oxygen evolution catalytic activity for practical applications.For this purpose,a Ti/SnO_(x)/MnO_(2) anode was fabricated through an innovative strategy involving Sn electrodeposition,oxidation,and MnO_(2)-layer preparation.The structure of the anode was characterized,and the oxygen evolution performance was evaluated in a H_(2)SO_(4) solution.The results show that compared with the Ti/SnO_(2)/MnO_(2) anode prepared by the conventional brushing-annealing process,the Ti/SnO_(x)/MnO_(2) anode fabricated through the innovative procedure exhibits a lower oxygen evolution potential and a nearly 40%longer accelerated lifespan.The superior oxygen evolution performance of the Ti/SnO_(x)/MnO_(2) anode is attributed to the distinctive SnO_(x) intermediate layer fabricated through Sn electrodeposition followed by oxidation,which indicates the great potential of the anode as a dimensionally stable anode for metal electrowinning and hydrogen production by electrolysis,etc.
文摘（S）-2-aminobutyric acid being initial raw material,（S）-2-hydroxybutyric acid methyl ester was synthesized by means of a three step reaction of hydroxylation, salification and esterification. The product had a yield rate of 60.4%, purity of 99% and ee value higher than 99% by characterization of GC, HPLC and 1H NMR. This synthesis technique has advantages of high purity and ee value, low cost, short reaction time and mild reaction conditions so that it is suitable for production on industrial scale.
基金supported by the National Key Research and Development Program of China(2022YFC2105904)the National Natural Science Foundation of China(22478043,22090030,52021004,U21A20312,22075033)。
文摘CO_(2)fixation is important for reducing the greenhouse effect and improving clean energy use.While recent studies focus on converting CO_(2)to liquid fuels,direct fixation into high-value compounds like aromatic carboxylic acids provides an alternative path.Herein,we report a general electrochemical CO_(2)fixation to aromatic carboxylic acids via the CO_(2)^(·-)intermediate using a non-transition metal graphite electrode.Different from the conventional aromatic radical mechanism,in this report,CO_(2)will gain electrons on the graphite electrode to generate CO_(2)^(·-),which will further attack aromatic halides to obtain the desired aromatic carboxylic acid via an aromatic nucleophilic substitution mechanism.As CO_(2)^(·-)acts as the general intermediate,various aromatic compounds can be carbonylated without the need for a specific catalytic design to activate the aromatic halides.Furthermore,benefit from the CO_(2)^(·-)nucleophile,only the ipso-products can be obtained compared with the conventional approaches.This method offers a flexible way to convert the greenhouse gas CO_(2)into valuable aromatic carboxylic acids,which have applications in pharmaceutical chemistry,biochemistry and polymer chemistry.Therefore,it holds the potential for furthering the objectives of carbon neutrality and green chemistry.
基金supported by the National Natural Science Foundation of China(62074102)the Guangdong Basic and Applied Basic Research Foundation(2022A1515010979)+1 种基金the Key Project of Department of Education of Guangdong Province(2018KZDXM059)the Science and Technology plan project of Shenzhen(20220808165025003)。
文摘Antimony selenide(Sb_(2)Se_(3))is a potential photovoltaic(PV)material for next-generation solar cells and has achieved great development in the last several years.The properties of Sb_(2)Se_(3)absorber and back contact influence the PV performances of Sb_(2)Se_(3)solar cells.Hence,optimization of back contact characteristics and absorber orientation are crucial steps in raising the power conversion efficiency(PCE)of Sb_(2)Se_(3)solar cells.In this work,MoO2was introduced as an intermediate layer(IL)in Sb_(2)Se_(3)solar cells,and comparative investigations were conducted.The growth of(211)-oriented Sb_(2)Se_(3)with large grains was facilitated by introducing the MoO2IL with suitable thickness.The MoO2IL substantially lowered the back contact barrier and prevented the formation of voids at the back contact,which reduced the thickness of the MoSe2interface layer,inhibited carrier recombination,and minimized bulk and interfacial defects in devices.Subsequently,significant optimization enhanced the open-circuit voltage(VOC)of solar cells from 0.481 V to 0.487 V,short-circuit current density(JSC)from 23.81 m A/cm^(2)to 29.29 m A/cm^(2),and fill factor from 50.28%to 57.10%,which boosted the PCE from 5.75%to 8.14%.
基金financially supported by the Swedish Research Council(2017-00935)the Knut and Alice Wallenberg Foundation(KAW 2016.0072)the China Scholarship Council(CSC).
文摘Isolation of RuⅢ-bda(17-electron specie)complex with an aqua ligand(2-electron donor)is challenging due to violation of the 18-electron rule.Although considerable efforts have been dedicated to mechanistic studies of water oxidation by the Ru-bda family,the structure and initial formation of the Ru^(Ⅲ)-bda aqua complex are still controversial.Herein,we challenge this often overlooked step by designing a pocketshape Ru-based complex 1.The computational studies showed that 1 possesses the crucial hydrophobicity at the Ru^(V)(O)state as well as similar probability of access of terminal O to solvent water molecules when compared with classic Ru-bda catalysts.Through characterization of single-crystal structures at the Ru^(Ⅱ) and Ru^(Ⅲ) states,a pseudo seven-coordinate“ready-togo”aqua ligand with Ru^(Ⅲ)…O distance of 3.62A was observed.This aqua ligand was also found to be part of a formed hydrogen-bonding network,providing a good indication of how the Ru^(Ⅲ)-OH_(2)complex is formed.
基金support was provided by the National Key Research and Development Program of China,Grant/Award Number:2023YFB4203900the Fundamental Research Funds for the Central Universities,Grant/Award Number:226‐2024‐00075.
文摘Direct hydrazine‐hydrogen peroxide fuel cells(DHzHPFCs)offer unique advantages for air‐independent applications,but their commercialization is impeded by the lack of high‐performance and low‐cost catalysts.This study reports a novel dual‐site Co‐Zn catalyst designed to enhance the hydrazine oxidation reaction(HzOR)activity.Density functional theory calculations suggested that incorporating Zn into Co catalysts can weaken the binding strength of the crucial N_(2)H_(3)*intermediate,which limits the ratedetermining N_(2)H_(3)*desorption step.The synthesized p‐Co_(9)Zn1 catalyst exhibited a remarkably low reaction potential of−0.15 V versus RHE at 10mAcm−2,outperforming monometallic Co catalysts.Experimental and computational analyses revealed dual active sites at the Co/ZnO interface,which facilitate N_(2)H_(3)*desorption and subsequent N_(2)H_(2)*formation.A liquidN_(2)H_(4)‐H_(2)O_(2)fuel cell with p‐Co_(9)Zn1 catalyst achieved a high open circuit voltage of 1.916 V and a maximum power density of 195mWcm^(−2),demonstrating the potential application of the dual‐site Co‐Zn catalyst.This rational design strategy of tuning the N_(2)H_(3)*binding energy through bimetallic interactions provides a pathway for developing efficient and economical non‐precious metal electrocatalysts for DHzHPFCs.
基金This work was supported by the Key Program and the Major Research Plan of the National Natural Science Foundation of China(30630012 and 90919020 to J.W.)National Basic Research Program of China(2010CB945001 and 2011CB965104)+2 种基金Ministry of Agriculture of the People’s Republic of China(2009ZX08006-010B)Program of Shanghai Subject Chief Scientist(10XD1402200 to J.W.)the Specialized Research Fund for the Doctoral Program of Higher Education(SRFDP)in China(20090073110032 to J.W.).
文摘Oocyte production in most mammalian species is believed to cease before birth.However,this idea has been challenged with the finding that postnatal mouse ovaries possess mitotically active germ cells.A recent study showed that female germline stem cells(FGSCs)from adult mice were isolated,cultured long term and produced oocytes and progeny after transplantation into infertile mice.Here,we demonstrate the successful generation of transgenic or gene knock-down mice using FGSCs.The FGSCs from ovaries of 5-day-old and adult mice were isolated and either infected with recombinant viruses carrying green fluorescent protein,Oocyte-G1 or the mouse dynein axonemal intermediate chain 2 gene,or transfected with the Oocyte-G1 specific shRNA expression vector(pRS shOocyte-G1 vector),and then transplanted into infertile mice.Transplanted cells in the ovaries underwent oogenesis and produced heterozygous offspring after mating with wild-type male mice.The offspring were genetically characterized and the biological functions of the transferred or knock-down genes were investigated.Efficiency of genetransfer or gene knock-down was 29%–37%and it took 2 months to produce transgenic offspring.Gene manipulation of FGSCs is a rapid and efficient method of animal transgenesis and may serve as a powerful tool for biomedical science and biotechnology.
基金supported by the National Key R&D Program of China(Grants No.2018YFA0703400)the National Natural Science Foundation of China(Grants Nos.51672238,91963203,51722209,and 51525205)+2 种基金M.Hu acknowledges fellowship support by the Alexander von Humboldt Foundation.Z.Zhao acknowledges 100 talents plan of Hebei Province(Grants No.E2016100013)NSF for Distinguished Young Scholars of Hebei Province of China(Grants No.E2018203349)K.Luo acknowledges the China Postdoctoral Science Foundation(Grants No.2017M620097).
文摘Glassy carbon(GC)is a type of non-graphitizing disordered carbon material at ambient pressure and high temperatures,which has been widely used due to its excellent mechanical properties.Here we report the changes in the microstructure and mechanical properties of GC treated at high pressures(up to 5 GPa)and high temperatures.The formation of intermediate sp2-sp3 phases is identified at moderate treatment temperatures before the complete graphitization of GC,by analyzing synchrotron X-ray diffraction,Raman spectra,and transmission electron microscopy images.The intermediate metastable carbon materials exhibit superior mechanical properties with hardness reaching up to 10 GPa and compressive strength reaching as high as 2.5 GPa,nearly doubling those of raw GC,and improving elasticity and thermal stability.The synthesis pressure used in this study can be achieved in the industry on a commercial scale,enabling the scalable synthesis of this type of strong,hard,and elastic carbon materials.
