A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nan...A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.展开更多
Main observation and conclusion Ring-opening polymerization(ROP)of cyclic esters in the presence of stannous octoate(Sn(Oct)2)is the main way to obtain biodegradable aliphatic polyesters,an important family of biodegr...Main observation and conclusion Ring-opening polymerization(ROP)of cyclic esters in the presence of stannous octoate(Sn(Oct)2)is the main way to obtain biodegradable aliphatic polyesters,an important family of biodegradable polymers which have been widely used and still rapidly developed in the fields of biomedical polymers and environment-friendly materials.展开更多
The aortic dissection(AD)is a life-threatening disease.The transcatheter endovascular aortic repair(EVAR)affords a minimally invasive technique to save the lives of these critical patients,and an appropriate stent-gra...The aortic dissection(AD)is a life-threatening disease.The transcatheter endovascular aortic repair(EVAR)affords a minimally invasive technique to save the lives of these critical patients,and an appropriate stent-graft gets to be the key medical device during an EVAR procedure.Herein,we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease.The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene(ePTFE)membranes.Each of the inner and outer surfaces of the stent-graft was covered by an ePTFE membrane,and the two membranes were then sintered together.The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro.Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability.The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo.In nine canine experiments,the blood vessels of the animals implanted with the stent-grafts were of good patency,and there were no thrombus and obvious stenosis by angiography after implantation for 6months.Furthermore,all of the nine clinical cases experienced successful implantation using the stent-graft and its postrelease delivery system,and the 1-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.展开更多
Expanded polytetrafluoroethylene(ePTFE)is promising in biomedical fields such as covered stents and plastic surgery owing to its excellent biocompatibility and mechanical properties.However,ePTFE material prepared by ...Expanded polytetrafluoroethylene(ePTFE)is promising in biomedical fields such as covered stents and plastic surgery owing to its excellent biocompatibility and mechanical properties.However,ePTFE material prepared by the traditional biaxial stretching process is with thicker middle and thinner sides due to the bowing effect,which poses a major problem in industrial-scale fabrication.To solve this problem,we design an olive-shaped winding roller to provide the middle part of the ePTFE tape with a greater longitudinal stretching amplitude than the two sides,so as to make up for the excessive longitudinal retraction tendency of the middle part when it is transversely stretched.The as-fabricated ePTFE membrane has,as designed,uniform thickness and node-fibril microstructure.In addition,we examine the effects of mass ratio of lubricant to PTFE powder,biaxial stretching ratio and sintering temperature on the performance of the resultant ePTFE membranes.Particularly,the relation between the internal microstructure of the ePTFE membrane and its mechanical properties is revealed.Besides stable mechanical properties,the sintered ePTFE membrane exhibits satisfactory biological properties.We make a series of biological assessments including in vitro hemolysis,coagulation,bacterial reverse mutation and in vivo thrombosis,intracutaneous reactivity test,pyrogen test and subchronic systemic toxicity test;all of the results meet the relevant international standards.The muscle implantation of the sintered ePTFE membrane into rabbits indicates acceptable inflammatory reactions of our sintered ePTFE membrane fabricated on industrial scale.Such a medical-grade raw material with the unique physical form and condensed-state microstructure is expected to afford an inert biomaterial potentially for stent-graft membrane.展开更多
基金Project supported by the Ningxia Natural Science Foundation of China(2023AAC03285)National Natural Science Foundation of China(21666001)+1 种基金Innovative Team for Transforming Waste Cooking Oil into Clean Energy and High Value-added Chemicals,ChinaNingxia Low-grade Resource High Value Utilization and Environmental Chemical Integration Technology Innovation Team Project,China。
文摘A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.Th e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.
基金This work was financially supported by National Key R&D Program of China(grant No.2016YFC1100300)NSF of China(grant Nos.21774024,21805041)+1 种基金China Postdoctoral Science Foundation(grant No.2018M632020)Zhuhai Fudan Innovation Institute(grant No.ZFCY-technology-2019-007).
文摘Main observation and conclusion Ring-opening polymerization(ROP)of cyclic esters in the presence of stannous octoate(Sn(Oct)2)is the main way to obtain biodegradable aliphatic polyesters,an important family of biodegradable polymers which have been widely used and still rapidly developed in the fields of biomedical polymers and environment-friendly materials.
基金financially supported by the National Science Foundation of China(Grant Nos.52130302,21961160721)the National Key R&D Program of China(Grant No.2016YFC1100300).
文摘The aortic dissection(AD)is a life-threatening disease.The transcatheter endovascular aortic repair(EVAR)affords a minimally invasive technique to save the lives of these critical patients,and an appropriate stent-graft gets to be the key medical device during an EVAR procedure.Herein,we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease.The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene(ePTFE)membranes.Each of the inner and outer surfaces of the stent-graft was covered by an ePTFE membrane,and the two membranes were then sintered together.The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro.Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability.The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo.In nine canine experiments,the blood vessels of the animals implanted with the stent-grafts were of good patency,and there were no thrombus and obvious stenosis by angiography after implantation for 6months.Furthermore,all of the nine clinical cases experienced successful implantation using the stent-graft and its postrelease delivery system,and the 1-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.
基金supports from National Natural Science Foundation of China(grant no.52130302)National Key R&D Program of China(grant no.2016YFC1100300)。
文摘Expanded polytetrafluoroethylene(ePTFE)is promising in biomedical fields such as covered stents and plastic surgery owing to its excellent biocompatibility and mechanical properties.However,ePTFE material prepared by the traditional biaxial stretching process is with thicker middle and thinner sides due to the bowing effect,which poses a major problem in industrial-scale fabrication.To solve this problem,we design an olive-shaped winding roller to provide the middle part of the ePTFE tape with a greater longitudinal stretching amplitude than the two sides,so as to make up for the excessive longitudinal retraction tendency of the middle part when it is transversely stretched.The as-fabricated ePTFE membrane has,as designed,uniform thickness and node-fibril microstructure.In addition,we examine the effects of mass ratio of lubricant to PTFE powder,biaxial stretching ratio and sintering temperature on the performance of the resultant ePTFE membranes.Particularly,the relation between the internal microstructure of the ePTFE membrane and its mechanical properties is revealed.Besides stable mechanical properties,the sintered ePTFE membrane exhibits satisfactory biological properties.We make a series of biological assessments including in vitro hemolysis,coagulation,bacterial reverse mutation and in vivo thrombosis,intracutaneous reactivity test,pyrogen test and subchronic systemic toxicity test;all of the results meet the relevant international standards.The muscle implantation of the sintered ePTFE membrane into rabbits indicates acceptable inflammatory reactions of our sintered ePTFE membrane fabricated on industrial scale.Such a medical-grade raw material with the unique physical form and condensed-state microstructure is expected to afford an inert biomaterial potentially for stent-graft membrane.
