The production of transgenic swine for xenotransplantation has been proposed as an optimal option to overcome the chronic shortage of human organ donors. Generation of genetically engineered swine has been elusive due...The production of transgenic swine for xenotransplantation has been proposed as an optimal option to overcome the chronic shortage of human organ donors. Generation of genetically engineered swine has been elusive due to the difficulties in gene transfer. In order to achieve effective gene delivery, a key step for the genetic modification, we applied electronic pulse delivery (EPD) technology to introduce HZKb-DC DNA construct into swine eggs. Using the developed EPD ProtocolsTM, we have achieved good viability of the EPD treated oocytes, satisfactory embryonic development of the EPD treated embryos, and stable DNA transfer into the swine embryos with high efficiency. Thus, application of the EPD technology promises to effectively facilitate the generation of large trangenic mammals.展开更多
Iron-based single-atom catalysts with nitrogen-doped carbon as support(Fe-SA/NPC)are considered effective alternatives to replace Pt-group metals for scalable application in fuel cells.However,synthesizing high-loadin...Iron-based single-atom catalysts with nitrogen-doped carbon as support(Fe-SA/NPC)are considered effective alternatives to replace Pt-group metals for scalable application in fuel cells.However,synthesizing high-loading Fe-SA catalysts by a simple procedure remains challenging.Herein,we report a high-loading(7.5 wt%)Fe-SA/NPC catalyst prepared by carbon-assisted pyrolysis of metal complexes.Both the nitrogen-doped porous carbon(NPC)support with high specific surface area and ο-phenylenediamine(o-PD)play key roles role in the preparation of high-loading Fe-SA/NPC catalysts.The results of X-ray photoelectron spectroscopy,high-angle annular dark-field scanning transmission electron microscopy,and X-ray absorption fine structure spectroscopy experiments show that the Fe atoms are anchored on the carbon carriers in a single-atom site configuration and coordinated with four of the doped nitrogen atoms of the carbon substrates(Fe-N_(4)).The activities of the Fe-SA/NPC catalysts in the oxygen reduction reaction increased with increasing iron loading.The optimized 250Fe-SA/NPC-800 catalyst exhibited an onset potential 0.97 V of and a half-wave potential of 0.85 V.Our study provides a simple approach for the large-scale synthesis of high-loading single-atom catalysts.展开更多
Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve ...Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.展开更多
Novel carbon nanohybrids based on unmodified metallofullerenes have been successfully fabricated for use as a new magnetic resonance imaging （MRI） contrast agent. The nanohybrids showed higher R1 relaxivity and bett...Novel carbon nanohybrids based on unmodified metallofullerenes have been successfully fabricated for use as a new magnetic resonance imaging （MRI） contrast agent. The nanohybrids showed higher R1 relaxivity and better brightening effect than Gd@C82（OH）x, in Tl-weighted MR images in vivo. This is a result of the proton relaxivity from the original gadofullerenes, which retained a perfect carbon cage structure and so might completely avoid the release of Gd^3＋ ions. A ＂secondary spin-electron transfer＂ relaxation mechanism was proposed to explain how the encaged Gd^3＋ ions of carbon nanohybrids interact with the surrounding water molecules. This approach opens new opportunities for developing highly efficient and low toxicity MRI contrast agents.展开更多
文摘The production of transgenic swine for xenotransplantation has been proposed as an optimal option to overcome the chronic shortage of human organ donors. Generation of genetically engineered swine has been elusive due to the difficulties in gene transfer. In order to achieve effective gene delivery, a key step for the genetic modification, we applied electronic pulse delivery (EPD) technology to introduce HZKb-DC DNA construct into swine eggs. Using the developed EPD ProtocolsTM, we have achieved good viability of the EPD treated oocytes, satisfactory embryonic development of the EPD treated embryos, and stable DNA transfer into the swine embryos with high efficiency. Thus, application of the EPD technology promises to effectively facilitate the generation of large trangenic mammals.
文摘Iron-based single-atom catalysts with nitrogen-doped carbon as support(Fe-SA/NPC)are considered effective alternatives to replace Pt-group metals for scalable application in fuel cells.However,synthesizing high-loading Fe-SA catalysts by a simple procedure remains challenging.Herein,we report a high-loading(7.5 wt%)Fe-SA/NPC catalyst prepared by carbon-assisted pyrolysis of metal complexes.Both the nitrogen-doped porous carbon(NPC)support with high specific surface area and ο-phenylenediamine(o-PD)play key roles role in the preparation of high-loading Fe-SA/NPC catalysts.The results of X-ray photoelectron spectroscopy,high-angle annular dark-field scanning transmission electron microscopy,and X-ray absorption fine structure spectroscopy experiments show that the Fe atoms are anchored on the carbon carriers in a single-atom site configuration and coordinated with four of the doped nitrogen atoms of the carbon substrates(Fe-N_(4)).The activities of the Fe-SA/NPC catalysts in the oxygen reduction reaction increased with increasing iron loading.The optimized 250Fe-SA/NPC-800 catalyst exhibited an onset potential 0.97 V of and a half-wave potential of 0.85 V.Our study provides a simple approach for the large-scale synthesis of high-loading single-atom catalysts.
基金the Ministry of Science and Technology of China(2017YFA0204504)the National Natural Science Foundation of China(51873221,52073292,51673207,21774003,and 51373183)+2 种基金Chinese Academy of Sciences and Dutch Research Project(1A111KYSB20190072)Beijing Municipal Science&Technology Commission(Z181100004418012)Beijing Natural Science Foundation(2212032).
文摘Introducing liquid-crystalline small-molecule donors(SMDs)into binary systems based on the strong intermolecular interactions of SMDs is a facile and effective strategy to tune the active layer morphology and improve the performance of organic solar cells(OSCs).Contrary to conventional understanding,this research proposes a new strategy for ternary OSCs implicating that"weakly crystalline materials can also optimize the morphology of the active layer and improve the OSCs performance".Herein,we designed and synthesized two liquid-crystalline SMDs,Z1 and Z2,based on benzodifuran(BDF)units.The amorphous Z2-incorporated ternary devices present an unexpectedly improved power conversion efficiency(PCE)>18%with good stability.By contrast,the highly ordered Z1-based ternary devices possess a significantly depressed efficiency.Multiple characterizations reveal that the Z2-based ternary blend films possess improved miscibility and efficient charge transport.This novel strategy for the selection of the third component is significant for the fabrication of high-efficiency ternary OSCs.
文摘Novel carbon nanohybrids based on unmodified metallofullerenes have been successfully fabricated for use as a new magnetic resonance imaging （MRI） contrast agent. The nanohybrids showed higher R1 relaxivity and better brightening effect than Gd@C82（OH）x, in Tl-weighted MR images in vivo. This is a result of the proton relaxivity from the original gadofullerenes, which retained a perfect carbon cage structure and so might completely avoid the release of Gd^3＋ ions. A ＂secondary spin-electron transfer＂ relaxation mechanism was proposed to explain how the encaged Gd^3＋ ions of carbon nanohybrids interact with the surrounding water molecules. This approach opens new opportunities for developing highly efficient and low toxicity MRI contrast agents.
