In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we dev...In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we developed an Mg-1Ca/polycaprolactone(Mg-1Ca/PCL)composite scaffolds to overcome these limitations.We used a melt blending method to prepare Mg-1Ca/PCL composites with Mg-1Ca alloy powder mass ratios of 5,10,and 20 wt%.Porous scaffolds with controlled macro-and microstructure were printed using the fused deposition modeling method.We explored the mechanical strength,biocompatibility,osteogenesis performance,and molecular mechanism of the Mg-1Ca/PCL composites.The 5 and 10 wt%Mg-1Ca/PCL composites were found to have good biocompatibility.Moreover,they promoted the mechanical strength,proliferation,adhesion,and osteogenic differentiation of human bone marrow stem cells(hBMSCs)of pure PCL.In vitro degradation experiments revealed that the composite material stably released Mg_(2)+ions for a long period;it formed an apatite layer on the surface of the scaffold that facilitated cell adhesion and growth.Microcomputed tomography and histological analysis showed that both 5 and 10 wt%Mg-1Ca/PCL composite scaffolds promoted bone regeneration bone defects.Our results indicated that the Wnt/β-catenin pathway was involved in the osteogenic effect.Therefore,Mg-1Ca/PCL composite scaffolds are expected to be a promising bone regeneration material for clinical application.Statement of significance:Bone tissue engineering scaffolds have promising applications in the regeneration of critical-sized bone defects.However,there remain many limitations in the materials and manufacturing methods used to fabricate scaffolds.This study shows that the developed Ma-1Ca/PCL composites provides scaffolds with suitable degradation rates and enhanced boneformation capabilities.Furthermore,the fused deposition modeling method allows precise control of the macroscopic morphology and microscopic porosity of the scaffold.The obtained porous scaffolds can significantly promote the regeneration of bone defects.展开更多
Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,in...Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.展开更多
Single-atom catalysts(SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis.However,a large room for improving their activity and durability remains.Herein,we...Single-atom catalysts(SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis.However,a large room for improving their activity and durability remains.Herein,we construct atomically dispersed Fe sites in N-doped carbon supports by secondary-atom-doped strategy.Upon the secondary doping,the density and coordination environment of active sites can be efficiently tuned,enabling the simultaneous improvement in the number and reactivity of the active site.Besides,structure optimizations in terms of the enlarged surface area and improved hydrophilicity can be achieved simultaneously.Due to the beneficial microstructure and abundant highly active FeN_5 moieties resulting from the secondary doping,the resultant catalyst exhibits an admirable half-wave potential of 0.81 V versus 0.83 V for Pt/C and much better stability than Pt/C in acidic media.This work would offer a general strategy for the design and preparation of highly active SACs for electrochemical energy devices.展开更多
Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phas...Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phases and difficult component design.In this work,the Ag/SnO2 composites are prepared by selective laser melting.To get better performance,Ag/SnO2 composites with different energy density were studied.The microstructure was observed by field emission scanning electron microscope.In addition,reinforced SnO2 phase was characterized by X-ray diffraction and transmission electron microscope.The results indicated that the microstructure,relative density and hardness of are influenced by energy density,while Ag/SnO2 composites with homogeneous microstructure,high relative density,higher hardness and lower electrical resistivity can be obtained by proper energy density(E?68 J/mm^3).展开更多
Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis hasbeen used as a traditional medicine for more than 2000 years in China and many other Asian countri...Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis hasbeen used as a traditional medicine for more than 2000 years in China and many other Asian countries. Thepharmacological activities of C. chinensis have been validated by research. Here, we present a de novo high-qualitygenome of C. chinensis with a chromosome-level genome of ~958.20 Mb, a contig N50 of 1.58 Mb, and a scaffold N50of 4.53 Mb. We found that the relatively large genome size of C. chinensis was caused by the amplification of longterminal repeat (LTR) retrotransposons. In addition, a whole-genome duplication event in ancestral Ranunculales wasdiscovered. Comparative genomic analysis revealed that the tyrosine decarboxylase (TYDC) and (S)-norcoclaurinesynthase (NCS) genes were expanded and that the aspartate aminotransferase gene (ASP5) was positively selected inthe berberine metabolic pathway. Expression level and HPLC analyses showed that the berberine content was highestin the roots of C. chinensis in the third and fourth years. The chromosome-level reference genome of C. chinensisprovides important genomic data for molecular-assisted breeding and active ingredient biosynthesis.展开更多
A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation...A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.展开更多
Atmospheric pressure cold plasma, with advantages such as high particle activity, no thermal damage, high efficiency and direct and friendly contact with human tissues, is considered to have great potential in biomedi...Atmospheric pressure cold plasma, with advantages such as high particle activity, no thermal damage, high efficiency and direct and friendly contact with human tissues, is considered to have great potential in biomedical applications. Therefore, 'plasma medicine' as a new interdiscipline has been developed in the past two decades. This review first briefly describes the development of typical plasma sources suitable for biomedical applications, and those with different discharge forms are simply compared, evaluated and summarized. Subsequently, measurement of the crucial gaseous reactive particles(e.g. OH and O) and their spatio-temporal distributions are introduced. Meanwhile, the generation and variation rules and the related critical macroscopic parameters of the plasma-induced aqueous reactive species are summarized. Finally, related studies in the last ten years on the mechanisms of the plasma-driven microbial inactivation and plasma-induced apoptosis of cancer cells are introduced. Moreover, some scientific problems that need to be urgently solved in the field of plasma medicine are also discussed. This review will provide useful guidance for future related research.展开更多
Benefiting from the ultrahigh specific surface areas,highly accessible surface atoms,and highly tunable microscopic structures,the two-dimensional metallenes as nanocatalysts have displayed promising performance for v...Benefiting from the ultrahigh specific surface areas,highly accessible surface atoms,and highly tunable microscopic structures,the two-dimensional metallenes as nanocatalysts have displayed promising performance for various electrocatalytic reactions.Herein,we reviewed recent advances on metallenes in structural regulations including defect,phase,strain,interface,doping,and alloying engineering strategies and their applications in energy electrocatalytic reactions involving oxygen reduction reaction,carbon dioxide reduction reaction,hydrogen evolution reaction,and small molecules oxidation reaction.Finally,we proposed the future challenges and directions in this emerging area.展开更多
Tumor vaccines,a type of personalized tumor immunotherapy,have developed rapidly in recent decades.These vaccines evoke tumor antigen-specific T cells to achieve immune recognition and killing of tumor cells.Because t...Tumor vaccines,a type of personalized tumor immunotherapy,have developed rapidly in recent decades.These vaccines evoke tumor antigen-specific T cells to achieve immune recognition and killing of tumor cells.Because the immunogenicity of tumor antigens alone is insufficient,immune adjuvants and nanocarriers are often required to enhance anti-tumor immune responses.At present,vaccine carrier development often integrates nanocarriers and immune adjuvants.Among them,outer membrane vesicles(OMVs)are receiving increasing attention as a delivery platform for tumor vaccines.OMVs are natural nanovesicles derived from Gramnegative bacteria,which have adjuvant function because they contain pathogen associated molecular patterns.Importantly,OMVs can be functionally modified by genetic engineering of bacteria,thus laying a foundation for applications as a delivery platform for tumor nanovaccines.This review summarizes 5 aspects of recent progress in,and future development of,OMV-based tumor nanovaccines:strain selection,heterogeneity,tumor antigen loading,immunogenicity and safety,and mass production of OMVs.展开更多
基金supported by the National Key R&D Program of China[grant number 2021YFC2400700]the National Natural Science Foundation of China[grant numbers 82170929,81970908 and 81771039].
文摘In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we developed an Mg-1Ca/polycaprolactone(Mg-1Ca/PCL)composite scaffolds to overcome these limitations.We used a melt blending method to prepare Mg-1Ca/PCL composites with Mg-1Ca alloy powder mass ratios of 5,10,and 20 wt%.Porous scaffolds with controlled macro-and microstructure were printed using the fused deposition modeling method.We explored the mechanical strength,biocompatibility,osteogenesis performance,and molecular mechanism of the Mg-1Ca/PCL composites.The 5 and 10 wt%Mg-1Ca/PCL composites were found to have good biocompatibility.Moreover,they promoted the mechanical strength,proliferation,adhesion,and osteogenic differentiation of human bone marrow stem cells(hBMSCs)of pure PCL.In vitro degradation experiments revealed that the composite material stably released Mg_(2)+ions for a long period;it formed an apatite layer on the surface of the scaffold that facilitated cell adhesion and growth.Microcomputed tomography and histological analysis showed that both 5 and 10 wt%Mg-1Ca/PCL composite scaffolds promoted bone regeneration bone defects.Our results indicated that the Wnt/β-catenin pathway was involved in the osteogenic effect.Therefore,Mg-1Ca/PCL composite scaffolds are expected to be a promising bone regeneration material for clinical application.Statement of significance:Bone tissue engineering scaffolds have promising applications in the regeneration of critical-sized bone defects.However,there remain many limitations in the materials and manufacturing methods used to fabricate scaffolds.This study shows that the developed Ma-1Ca/PCL composites provides scaffolds with suitable degradation rates and enhanced boneformation capabilities.Furthermore,the fused deposition modeling method allows precise control of the macroscopic morphology and microscopic porosity of the scaffold.The obtained porous scaffolds can significantly promote the regeneration of bone defects.
基金the National Natural Science Foundation of China(22279044,12034002,and 22202080)the Project for Self-Innovation Capability Construction of Jilin Province Development and Reform Commission(2021C026)+1 种基金Jilin Province Science and Technology Development Program(20210301009GX)the Fundamental Research Funds for the Central Universities.
文摘Electrochemical carbon dioxide reduction reaction(CO_(2)RR)involves a variety of intermediates with highly correlated reaction and ad-desorption energies,hindering optimization of the catalytic activity.For example,increasing the binding of the*COOH to the active site will generally increase the*CO desorption energy.Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO_(2)RR,but remains an unsolved challenge.Herein,we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier.This system shows an unprecedented CO_(2)RR intrinsic activity with TOF of 3336 h−1,high selectivity toward CO production,Faradaic efficiency of 95.96%at−0.60 V and excellent stability.Theoretical calculations show that the Mo-Fe diatomic sites increased the*COOH intermediate adsorption energy by bridging adsorption of*COOH intermediates.At the same time,d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of*CO intermediates.Thus,the undesirable correlation between these steps is broken.This work provides a promising approach,specifically the use of di-atoms,for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale.
基金the financial support of the Fundamental Research Funds for the Central Universities (CCNU20QN007, CCNU20TS013)the Program of Introducing Talents of Discipline to Universities of China (111 program, B17019)the Recruitment Program of Global Youth Experts of China。
文摘Single-atom catalysts(SACs) with nitrogen-coordinated nonprecious metal sites have exhibited inimitable advantages in electrocatalysis.However,a large room for improving their activity and durability remains.Herein,we construct atomically dispersed Fe sites in N-doped carbon supports by secondary-atom-doped strategy.Upon the secondary doping,the density and coordination environment of active sites can be efficiently tuned,enabling the simultaneous improvement in the number and reactivity of the active site.Besides,structure optimizations in terms of the enlarged surface area and improved hydrophilicity can be achieved simultaneously.Due to the beneficial microstructure and abundant highly active FeN_5 moieties resulting from the secondary doping,the resultant catalyst exhibits an admirable half-wave potential of 0.81 V versus 0.83 V for Pt/C and much better stability than Pt/C in acidic media.This work would offer a general strategy for the design and preparation of highly active SACs for electrochemical energy devices.
基金sponsored by the Natural Science Foundation of China (Grant nos. 51775208)the Hubei Science Fund for Distinguished Young Scholars (No. 0216110085)+2 种基金the National Key Research and Development Program “Additive Manufacturing and Laser Manufacturing”(No. 2016YFB1100101)Wuhan Morning Light Plan of Youth Science and Technology (No. 0216110066)the Academic frontier youth team at Huazhong University of Science and Technology (HUST)
文摘Ag/SnO2,as a promising and environment-friendly electrical contact material,is widely applied in low-voltage apparatus.But the properties of Ag/SnO2 composites is difficult to improve due to the poor distribution phases and difficult component design.In this work,the Ag/SnO2 composites are prepared by selective laser melting.To get better performance,Ag/SnO2 composites with different energy density were studied.The microstructure was observed by field emission scanning electron microscope.In addition,reinforced SnO2 phase was characterized by X-ray diffraction and transmission electron microscope.The results indicated that the microstructure,relative density and hardness of are influenced by energy density,while Ag/SnO2 composites with homogeneous microstructure,high relative density,higher hardness and lower electrical resistivity can be obtained by proper energy density(E?68 J/mm^3).
基金the Basic Research Projects of Chongqing Province(No.cstc2017jxjl-jbky-120013)China National Science and Technology Project of the 12th 5-Year Plan(2011BAI13B02-1)Chongqing Platform and Base Construction Project(cstc2014ptjd10001).
文摘Coptis chinensis Franch, a perennial herb, is mainly distributed in southeastern China. The rhizome of C. chinensis hasbeen used as a traditional medicine for more than 2000 years in China and many other Asian countries. Thepharmacological activities of C. chinensis have been validated by research. Here, we present a de novo high-qualitygenome of C. chinensis with a chromosome-level genome of ~958.20 Mb, a contig N50 of 1.58 Mb, and a scaffold N50of 4.53 Mb. We found that the relatively large genome size of C. chinensis was caused by the amplification of longterminal repeat (LTR) retrotransposons. In addition, a whole-genome duplication event in ancestral Ranunculales wasdiscovered. Comparative genomic analysis revealed that the tyrosine decarboxylase (TYDC) and (S)-norcoclaurinesynthase (NCS) genes were expanded and that the aspartate aminotransferase gene (ASP5) was positively selected inthe berberine metabolic pathway. Expression level and HPLC analyses showed that the berberine content was highestin the roots of C. chinensis in the third and fourth years. The chromosome-level reference genome of C. chinensisprovides important genomic data for molecular-assisted breeding and active ingredient biosynthesis.
基金financial support from the National Key Research&Development Program of China(2018YFB0604901)the National Natural Science Foundation of China(21706210)the Key Research&Development Program of Shaanxi Province(2020ZDLGY11-06)。
文摘A series of ZnO-ZrO_(2) solid solutions with different Zn contents were synthesized by the urea coprecipitation method,which were coupled with H-ZSM-5 zeolite to form bifunctional catalysts.As a new benzene alkylation reagent,syngas was used instead of methanol to realize the efficient conversion of syngas and benzene into toluene and xylene.A suitable ratio of ZnO-ZrO_(2) led to the significant improvement in the catalytic performance,and a suitable amount of acid helped to increase the selectivity of toluene/xylene and reduce the selectivity of the by-products ethylbenzene and C^(9+) aromatics.The highest benzene conversion of 89.2%and toluene/xylene selectivity of 88.7%were achieved over 10%ZnO-ZrO_(2)&H-ZSM-5(Si/Al=23)at a pressure of 3 MPa and a temperature of 450℃.In addition,the effect of the zeolite framework structure on product distribution was examined.Similar to the molecular dynamics of aromatic hydrocarbons,H-ZSM-5 zeolites comprise 10-membered-ring pores,which are beneficial to the activation of benzene;hence,the conversion of benzene is higher.H-ZSM-35 and HMOR zeolites exhibited small eight-membered-ring channels,which were not conducive to the passage of benzene;hence,the by-product ethylbenzene exhibits a higher selectivity.The distance between the active centers of the bifunctional catalysts was the main factor affecting the catalytic performance,and the powder mixing method was more conducive to the conversion of syngas and benzene.
基金financially supported by National Natural Science Foundation of China (Grant Nos. 51777206, 51807046 and 51877208)the Natural Science Foundation of Anhui Province (Grant Nos. 1908085MA29 and 1808085MA13)。
文摘Atmospheric pressure cold plasma, with advantages such as high particle activity, no thermal damage, high efficiency and direct and friendly contact with human tissues, is considered to have great potential in biomedical applications. Therefore, 'plasma medicine' as a new interdiscipline has been developed in the past two decades. This review first briefly describes the development of typical plasma sources suitable for biomedical applications, and those with different discharge forms are simply compared, evaluated and summarized. Subsequently, measurement of the crucial gaseous reactive particles(e.g. OH and O) and their spatio-temporal distributions are introduced. Meanwhile, the generation and variation rules and the related critical macroscopic parameters of the plasma-induced aqueous reactive species are summarized. Finally, related studies in the last ten years on the mechanisms of the plasma-driven microbial inactivation and plasma-induced apoptosis of cancer cells are introduced. Moreover, some scientific problems that need to be urgently solved in the field of plasma medicine are also discussed. This review will provide useful guidance for future related research.
文摘Benefiting from the ultrahigh specific surface areas,highly accessible surface atoms,and highly tunable microscopic structures,the two-dimensional metallenes as nanocatalysts have displayed promising performance for various electrocatalytic reactions.Herein,we reviewed recent advances on metallenes in structural regulations including defect,phase,strain,interface,doping,and alloying engineering strategies and their applications in energy electrocatalytic reactions involving oxygen reduction reaction,carbon dioxide reduction reaction,hydrogen evolution reaction,and small molecules oxidation reaction.Finally,we proposed the future challenges and directions in this emerging area.
基金supported by grants from the National Key R&D Program of China(Grant No.2021YFA0909900,X.Z.)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-010,X.Z.)+2 种基金the Beijing Natural Science Foundation(Grant No.Z200020,X.Z.)the Beijing Nova Program(Grant No.Z201100006820031,X.Z.)the National Natural Science Foundation of China(Grant No.32171384,X.Z.).
文摘Tumor vaccines,a type of personalized tumor immunotherapy,have developed rapidly in recent decades.These vaccines evoke tumor antigen-specific T cells to achieve immune recognition and killing of tumor cells.Because the immunogenicity of tumor antigens alone is insufficient,immune adjuvants and nanocarriers are often required to enhance anti-tumor immune responses.At present,vaccine carrier development often integrates nanocarriers and immune adjuvants.Among them,outer membrane vesicles(OMVs)are receiving increasing attention as a delivery platform for tumor vaccines.OMVs are natural nanovesicles derived from Gramnegative bacteria,which have adjuvant function because they contain pathogen associated molecular patterns.Importantly,OMVs can be functionally modified by genetic engineering of bacteria,thus laying a foundation for applications as a delivery platform for tumor nanovaccines.This review summarizes 5 aspects of recent progress in,and future development of,OMV-based tumor nanovaccines:strain selection,heterogeneity,tumor antigen loading,immunogenicity and safety,and mass production of OMVs.
