Metal–organic frameworks(MOFs) are crystalline porous materials with tunable properties, exhibiting great potential in gas adsorption, separation and catalysis.[1,2]It is challenging to visualize MOFs with transmissi...Metal–organic frameworks(MOFs) are crystalline porous materials with tunable properties, exhibiting great potential in gas adsorption, separation and catalysis.[1,2]It is challenging to visualize MOFs with transmission electron microscopy(TEM) due to their inherent instability under electron beam irradiation. Here, we employ cryo-electron microscopy(cryoEM) to capture images of MOF ZIF-8, revealing inverted-space structural information at a resolution of up to about 1.7A and enhancing its critical electron dose to around 20 e^(-)/A^(2). In addition, it is confirmed by electron-beam irradiation experiments that the high voltage could effectively mitigate the radiolysis, and the structure of ZIF-8 is more stable along the [100] direction under electron beam irradiation. Meanwhile, since the high-resolution electron microscope images are modulated by contrast transfer function(CTF) and it is difficult to determine the positions corresponding to the atomic columns directly from the images. We employ image deconvolution to eliminate the impact of CTF and obtain the structural images of ZIF-8. As a result, the heavy atom Zn and the organic imidazole ring within the organic framework can be distinguished from structural images.展开更多
Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted...Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted as ZnS(en)0.5)as a hard template.Inorganic–organic hybrid ZnS(en)0.5,Cd0.5Zn0.5S(en)x,and Cd0.5Zn0.5S nanosheets were sequentially fabricated,and their transformation processes were analyzed in detail.The fabricated Cd0.5Zn0.5S nanosheets exhibited high photocatalytic hydrogen evolution reaction activity in the presence of a sacrificial agent.The Cd0.5Zn0.5S nanosheets exhibited remarkably high H2 production activity of~1395μmol∙h^−1∙g^−1 in pure water with no co-catalyst,which is the highest value reported thus far for bare photocatalysts,to the best of our knowledge.The high activity of these nanosheets is attributed to their distinct nanostructure(e.g.,short transfer distance of photoinduced charge carriers,large number of unsaturated surface atoms,and large surface area).Moreover,ternary NiCo2S4 nanoparticles were employed to facilitate the charge separation and enhance the surface kinetics of H2 evolution.The H2 production rate reached~62.2 and~2436μmol∙h^−1∙g^−1 in triethanolamine and pure water,respectively,over the NiCo2S4/Cd0.5Zn0.5S heterojunctions.The result indicated that the Schottky junction was critical to the enhanced activity.The proposed method can be used for fabricating other highly efficient CdZnS-based photocatalysts for solar-energy conversion or other applications.展开更多
In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibit...In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.展开更多
The thermoelectric parameters are essentially governed by electron and phonon transport.Since the carrier scattering mechanism plays a decisive role in electron transport,it is of great significance for the electrical...The thermoelectric parameters are essentially governed by electron and phonon transport.Since the carrier scattering mechanism plays a decisive role in electron transport,it is of great significance for the electrical properties of thermoelectric materials.As a typical example,the defect-dominated carrier scattering mechanism can significantly impact the room-temperature electron mobility of n-type Mg_(3)Sb_(2)-based materials.However,the origin of such a defect scattering mechanism is still controversial.Herein,the existence of the Mg vacancies and Mg interstitials has been identified by synchrotron powder X-ray diffraction.The relationship among the point defects,chemical compositions,and synthesis conditions in Mg_(3)Sb_(2)-based materials has been revealed.By further introducing the point defects without affecting the grain size via neutron irradiation,the thermally activated electrical conductivity can be reproduced.Our results demonstrate that the point defects scattering of electrons is important in the n-type Mg_(3)Sb_(2)-based materials.展开更多
Esophageal cancer(EC)is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide.Therefore,exploring the pathogenesis of ECand searching for new targeted therapi...Esophageal cancer(EC)is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide.Therefore,exploring the pathogenesis of ECand searching for new targeted therapies are the current research hotspot for EC treatment.Long non-coding RNAs(lncRNAs)are endogenous RNAs with more than 200 nucleotides,but without proteincoding function.In recent years,lncRNAs have gradually become the focuses in the field of non-coding RNA.Some lncRNAs have been proved to be closely related to the pathogenesis of EC.Many lncRNAs are abnormally expressed in EC and participate in many biological processes including cell proliferation,apoptosis,and metastasis by inhibiting or promoting target gene expression.LncRNAs can also regulate the progression of EC through epithelial-mesenchymal transformation(EMT),which is closely related to the occurrence,development,and prognosis of EC.In this article,we review and discuss the involvement of lncRNAs in the progression of EC.展开更多
Hypoxia mediates a metabolic switch from oxidative phosphorylation to glycolysis and increases glycogen synthesis.We previously found that glycogen branching enzyme(GBE1)is downstream of the hypoxia-inducible factor-1...Hypoxia mediates a metabolic switch from oxidative phosphorylation to glycolysis and increases glycogen synthesis.We previously found that glycogen branching enzyme(GBE1)is downstream of the hypoxia-inducible factor-1(HIF1)signaling pathway in lung adenocarcinoma(LUAD)cells;however,the molecular mechanism underlying HIF1 regulation of GBE1 expression remains unknown.Herein,the effect of GBE1 on tumor progression via changes in metabolic signaling under hypoxia in vitro and in vivo was evaluated,and GBE1-related genes from human specimens and data sets were analyzed.Hypoxia induced GBE1 upregulation in LUAD cells.GBE1-knockdown A549 cells showed impaired cell proliferation,clone formation,cell migration and invasion,angiogenesis,tumor growth,and metastasis.GBE1 mediated the metabolic reprogramming of LUAD cells.The expression of gluconeogenesis pathway molecules,especially fructose-1,6-bisphosphatase(FBP1),was markedly higher in shGBE1 A549 cells than it was in the control cells.FBP1 inhibited the tumor progression of LUAD.GBE1-mediated FBP1 suppression via promoter methylation enhanced HIF1αlevels through NF-κB signaling.GBE1 may be a negative prognostic biomarker for LUAD patients.Altogether,hypoxia-induced HIF1αmediated GBE1 upregulation,suppressing FBP1 expression by promoter methylation via NF-κB signaling in LUAD cells.FBP1 blockade upregulated HIF1α,triggered the switch to anaerobic glycolysis,and enhanced glucose uptake.Therefore,targeting HIF1α/GBE1/NF-κB/FBP1 signaling may be a potential therapeutic strategy for LUAD.展开更多
The solubility range of interstitial Ni in the ZrNi1+xSn half-Heusler phase is a controversial issue,but it has an impact on the thermoelectric properties.In this study,two isothermal section phase diagrams of the Zr-...The solubility range of interstitial Ni in the ZrNi1+xSn half-Heusler phase is a controversial issue,but it has an impact on the thermoelectric properties.In this study,two isothermal section phase diagrams of the Zr-Ni-Sn ternary system at 973K and 1173 K were experimentally constructed based on the binary phase diagrams of Zr-Ni,Zr-Sn,and Ni-Sn.The thermodynamic equilibrium phases were obtained after a long time of heating treatment on the raw alloys prepared by levitation melting.Solubilities of x<0:07 at 973 K and x<0:13 at 1173 K were clearly indicated.An intermediate-Heusler phase with a partly filled Ni void was observed,which is believed to be beneficial to the lowered lattice thermal conductivity.The highest ZT value~0:71 at 973 K was obtained for ZrNi_(1.11)Sn_(1.04).The phase boundary mapping provides an important instruction for the further optimization of ZrNiSn-based materials and other systems.展开更多
Thermoelectric devices require thermoelectric materials with high figure-of-merit(ZT)values in the operating temperature range.In recent years,the Zintl phase compound,n-Mg_(3)Sb_(2),has received much attention owing ...Thermoelectric devices require thermoelectric materials with high figure-of-merit(ZT)values in the operating temperature range.In recent years,the Zintl phase compound,n-Mg_(3)Sb_(2),has received much attention owing to its rich chemistry and structural complexity.However,it hardly achieves high ZT values throughout the medium temperature range.Herein,by increasing the sintering temperature as much as possible,we successfully increased the average grain size of the compound by 15 times,and the grain boundary scattering was manipulated to obtain high carrier mobility of up to 180 cm^(2)V^(-1)s^(-1).Simultaneously,we optimized the Mg content for ultralow lattice thermal conductivity.We first doped the Mg_(3)Sb_(2)-based materials with boron for higher sintering temperature,good thermal stability,and higher hardness.The synergistic optimization of electrical and thermal transport resulted in excellent ZT values(0.62 at 300 K,1.81 at 773 K)and an average ZT of 1.4(from300 to 773 K),which are higher than the state-of-the-art values for n-type thermoelectric materials,demonstrating a high potential in device applications.展开更多
Zintl-phase compounds have great potential in thermoelectric applications owing to their“phonon glasselectron crystal”(PGEC)structures.In this paper,a new Zintlphase thermoelectric material Ba Ag Sb is reported.Ba d...Zintl-phase compounds have great potential in thermoelectric applications owing to their“phonon glasselectron crystal”(PGEC)structures.In this paper,a new Zintlphase thermoelectric material Ba Ag Sb is reported.Ba deficiency increased the carrier concentration,and then suppressed the intrinsic excitation.The peak ZT value of Ba_(0.98)Ag Sb reached~0.56 at 773 K.Moreover,Eu alloying at Ba site not only lowered the lattice thermal conductivity by inducing point-defect scattering,but also improved the electrical properties by increasing the carrier mobility.Finally,a peak ZT of~0.73 was achieved in Ba_(0.78)Eu_(0.2)Ag Sb.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074409 and 12374021)。
文摘Metal–organic frameworks(MOFs) are crystalline porous materials with tunable properties, exhibiting great potential in gas adsorption, separation and catalysis.[1,2]It is challenging to visualize MOFs with transmission electron microscopy(TEM) due to their inherent instability under electron beam irradiation. Here, we employ cryo-electron microscopy(cryoEM) to capture images of MOF ZIF-8, revealing inverted-space structural information at a resolution of up to about 1.7A and enhancing its critical electron dose to around 20 e^(-)/A^(2). In addition, it is confirmed by electron-beam irradiation experiments that the high voltage could effectively mitigate the radiolysis, and the structure of ZIF-8 is more stable along the [100] direction under electron beam irradiation. Meanwhile, since the high-resolution electron microscope images are modulated by contrast transfer function(CTF) and it is difficult to determine the positions corresponding to the atomic columns directly from the images. We employ image deconvolution to eliminate the impact of CTF and obtain the structural images of ZIF-8. As a result, the heavy atom Zn and the organic imidazole ring within the organic framework can be distinguished from structural images.
文摘Two-dimensional mesoporous ultrathin Cd0.5Zn0.5S nanosheets with a thickness of~1.5 nm were fabricated using a multistep chemical transformation strategy involving inorganic–organic hybrid ZnS-ethylenediamine(denoted as ZnS(en)0.5)as a hard template.Inorganic–organic hybrid ZnS(en)0.5,Cd0.5Zn0.5S(en)x,and Cd0.5Zn0.5S nanosheets were sequentially fabricated,and their transformation processes were analyzed in detail.The fabricated Cd0.5Zn0.5S nanosheets exhibited high photocatalytic hydrogen evolution reaction activity in the presence of a sacrificial agent.The Cd0.5Zn0.5S nanosheets exhibited remarkably high H2 production activity of~1395μmol∙h^−1∙g^−1 in pure water with no co-catalyst,which is the highest value reported thus far for bare photocatalysts,to the best of our knowledge.The high activity of these nanosheets is attributed to their distinct nanostructure(e.g.,short transfer distance of photoinduced charge carriers,large number of unsaturated surface atoms,and large surface area).Moreover,ternary NiCo2S4 nanoparticles were employed to facilitate the charge separation and enhance the surface kinetics of H2 evolution.The H2 production rate reached~62.2 and~2436μmol∙h^−1∙g^−1 in triethanolamine and pure water,respectively,over the NiCo2S4/Cd0.5Zn0.5S heterojunctions.The result indicated that the Schottky junction was critical to the enhanced activity.The proposed method can be used for fabricating other highly efficient CdZnS-based photocatalysts for solar-energy conversion or other applications.
文摘In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.
基金supported by the Shenzhen Science and Technology Program(KQTD20200820113045081)the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology.Q.Z.acknowledges the financial support from the National Natural Science Foundation of China(52172194,51971081)+7 种基金the Natural Science Foundation of Guangdong Province for Distinguished Young Scholars of China(2020B1515020023)the Natural Science Foundation for Distinguished Young Scholars of Shenzhen(RCJC20210609103733073)the Key Project of Shenzhen Fundamental Research Projects(JCYJ20200109113418655)F.C.acknowledges the financial support from the National Natural Science Foundation of China(51871081)J.M.acknowledges the financial support from the National Natural Science Foundation of China(52101248)the Shenzhen Fundamental Research Projects(JCYJ20210324132808020)the Start-Up Funding of Shenzhen,and the Start-Up Funding of Harbin Institute of Technology(Shenzhen).Y.M.W.acknowledges the financial support from the National Natural Science Foundation of China(12074409)H.Y.and Y.C.are grateful for the support of the Environment and Conservation Fund(69/2018)and the Research Computing Facilities offered by ITS,HKU.We thank Dr.Tiancheng Yi for his kind help in the neutron irradiation experiment.
文摘The thermoelectric parameters are essentially governed by electron and phonon transport.Since the carrier scattering mechanism plays a decisive role in electron transport,it is of great significance for the electrical properties of thermoelectric materials.As a typical example,the defect-dominated carrier scattering mechanism can significantly impact the room-temperature electron mobility of n-type Mg_(3)Sb_(2)-based materials.However,the origin of such a defect scattering mechanism is still controversial.Herein,the existence of the Mg vacancies and Mg interstitials has been identified by synchrotron powder X-ray diffraction.The relationship among the point defects,chemical compositions,and synthesis conditions in Mg_(3)Sb_(2)-based materials has been revealed.By further introducing the point defects without affecting the grain size via neutron irradiation,the thermally activated electrical conductivity can be reproduced.Our results demonstrate that the point defects scattering of electrons is important in the n-type Mg_(3)Sb_(2)-based materials.
基金supported by the Natural Science Foundation of Henan Province of China(202300410460)Henan Province Medical Science and Technology Research Project Joint Construction Project(Grant No.LHGJ20190003,LHGJ20190055)the National Natural Science Foundation of China(Grant No.31670895).
文摘Esophageal cancer(EC)is one of the most common malignant tumors of the digestive system with high incidence and mortality rate worldwide.Therefore,exploring the pathogenesis of ECand searching for new targeted therapies are the current research hotspot for EC treatment.Long non-coding RNAs(lncRNAs)are endogenous RNAs with more than 200 nucleotides,but without proteincoding function.In recent years,lncRNAs have gradually become the focuses in the field of non-coding RNA.Some lncRNAs have been proved to be closely related to the pathogenesis of EC.Many lncRNAs are abnormally expressed in EC and participate in many biological processes including cell proliferation,apoptosis,and metastasis by inhibiting or promoting target gene expression.LncRNAs can also regulate the progression of EC through epithelial-mesenchymal transformation(EMT),which is closely related to the occurrence,development,and prognosis of EC.In this article,we review and discuss the involvement of lncRNAs in the progression of EC.
基金supported by grants from the National Key Research and Development Program of China(Nos.2017YFC0909900 and 2016YFC1303500)the National Natural Science Foundation of China(Nos.81872410,U1804281,81771781,81602024 and 71673254)+1 种基金Doctor research team fund from The First Affiliated Hospital of Zhengzhou University(No.2016-BSTDJJ-15)the Program of Science&Technology of Henan Province(No.201602037).
文摘Hypoxia mediates a metabolic switch from oxidative phosphorylation to glycolysis and increases glycogen synthesis.We previously found that glycogen branching enzyme(GBE1)is downstream of the hypoxia-inducible factor-1(HIF1)signaling pathway in lung adenocarcinoma(LUAD)cells;however,the molecular mechanism underlying HIF1 regulation of GBE1 expression remains unknown.Herein,the effect of GBE1 on tumor progression via changes in metabolic signaling under hypoxia in vitro and in vivo was evaluated,and GBE1-related genes from human specimens and data sets were analyzed.Hypoxia induced GBE1 upregulation in LUAD cells.GBE1-knockdown A549 cells showed impaired cell proliferation,clone formation,cell migration and invasion,angiogenesis,tumor growth,and metastasis.GBE1 mediated the metabolic reprogramming of LUAD cells.The expression of gluconeogenesis pathway molecules,especially fructose-1,6-bisphosphatase(FBP1),was markedly higher in shGBE1 A549 cells than it was in the control cells.FBP1 inhibited the tumor progression of LUAD.GBE1-mediated FBP1 suppression via promoter methylation enhanced HIF1αlevels through NF-κB signaling.GBE1 may be a negative prognostic biomarker for LUAD patients.Altogether,hypoxia-induced HIF1αmediated GBE1 upregulation,suppressing FBP1 expression by promoter methylation via NF-κB signaling in LUAD cells.FBP1 blockade upregulated HIF1α,triggered the switch to anaerobic glycolysis,and enhanced glucose uptake.Therefore,targeting HIF1α/GBE1/NF-κB/FBP1 signaling may be a potential therapeutic strategy for LUAD.
基金This work was funded by the National Natural Science Foundation of China(51971081,11674078,and 51871081)the National Key Research&Development Program of China(2017YFA0303600)+2 种基金the National Natural Science Foundation of Guangdong Province of China(2018A0303130033)Shenzhen Fundamental Research Projects(JCYJ20170811155832192)Shenzhen Science and Technology Innovation Plan(KQISCX20180328165435202).
文摘The solubility range of interstitial Ni in the ZrNi1+xSn half-Heusler phase is a controversial issue,but it has an impact on the thermoelectric properties.In this study,two isothermal section phase diagrams of the Zr-Ni-Sn ternary system at 973K and 1173 K were experimentally constructed based on the binary phase diagrams of Zr-Ni,Zr-Sn,and Ni-Sn.The thermodynamic equilibrium phases were obtained after a long time of heating treatment on the raw alloys prepared by levitation melting.Solubilities of x<0:07 at 973 K and x<0:13 at 1173 K were clearly indicated.An intermediate-Heusler phase with a partly filled Ni void was observed,which is believed to be beneficial to the lowered lattice thermal conductivity.The highest ZT value~0:71 at 973 K was obtained for ZrNi_(1.11)Sn_(1.04).The phase boundary mapping provides an important instruction for the further optimization of ZrNiSn-based materials and other systems.
基金supported by the National Natural Science Foundation of China(51771065 and 51871082)the Natural Science Foundation of Heilongjiang Province of China(ZD2020E003)。
文摘Thermoelectric devices require thermoelectric materials with high figure-of-merit(ZT)values in the operating temperature range.In recent years,the Zintl phase compound,n-Mg_(3)Sb_(2),has received much attention owing to its rich chemistry and structural complexity.However,it hardly achieves high ZT values throughout the medium temperature range.Herein,by increasing the sintering temperature as much as possible,we successfully increased the average grain size of the compound by 15 times,and the grain boundary scattering was manipulated to obtain high carrier mobility of up to 180 cm^(2)V^(-1)s^(-1).Simultaneously,we optimized the Mg content for ultralow lattice thermal conductivity.We first doped the Mg_(3)Sb_(2)-based materials with boron for higher sintering temperature,good thermal stability,and higher hardness.The synergistic optimization of electrical and thermal transport resulted in excellent ZT values(0.62 at 300 K,1.81 at 773 K)and an average ZT of 1.4(from300 to 773 K),which are higher than the state-of-the-art values for n-type thermoelectric materials,demonstrating a high potential in device applications.
基金supported by the National Natural Science Foundation of China (51871081, 11674078, 51971081, and 52001339)the Cheung Kong Scholar Reward Program Young Scholar Program of China (Q2018239)+3 种基金the Natural Science Foundation of Guangdong Province of China (2018A0303130033)the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province (2020B1515020023)Shenzhen Science and Technology Innovation Plan (KQJSCX20180328165435202 and JCYJ20180307154619840)the National Key Research and Development Program of China (2017YFA0303600)
文摘Zintl-phase compounds have great potential in thermoelectric applications owing to their“phonon glasselectron crystal”(PGEC)structures.In this paper,a new Zintlphase thermoelectric material Ba Ag Sb is reported.Ba deficiency increased the carrier concentration,and then suppressed the intrinsic excitation.The peak ZT value of Ba_(0.98)Ag Sb reached~0.56 at 773 K.Moreover,Eu alloying at Ba site not only lowered the lattice thermal conductivity by inducing point-defect scattering,but also improved the electrical properties by increasing the carrier mobility.Finally,a peak ZT of~0.73 was achieved in Ba_(0.78)Eu_(0.2)Ag Sb.
