Supramolecular peptide nanofiber hydrogels are emerging biomaterials for tissue engineering,but it is difficult to fabricate multi-functional systems by simply mixing several short-motif-modified supramolecular peptid...Supramolecular peptide nanofiber hydrogels are emerging biomaterials for tissue engineering,but it is difficult to fabricate multi-functional systems by simply mixing several short-motif-modified supramolecular peptides because relatively abundant motifs generally hinder nanofiber cross-linking or the formation of long nanofiber.Coupling bioactive factors to the assembling backbone is an ideal strategy to design multi-functional supramolecular peptides in spite of challenging synthesis and purification.Herein,a multi-functional supramolecular peptide,P1R16,is developed by coupling a bioactive factor,parathyroid hormone related peptide 1(PTHrP-1),to the basic supramolecular peptide RADA16-I via solid-phase synthesis.It is found that P1R16 self-assembles into long nanofibers and co-assembles with RADA16-I to form nanofiber hydrogels,thus coupling PTHrP-1 to hydrogel matrix.P1R16 nanofiber retains osteoinductive activity in a dose-dependent manner,and P1R16/RADA16-I nanofiber hydrogels promote osteogenesis,angiogenesis and osteoclastogenesis in vitro and induce multi-functionalized osteoregeneration by intramembranous ossification and bone remodeling in vivo when loaded to collagen(Col)scaffolds.Abundant red blood marrow formation,ideal osteointegration and adapted degradation are observed in the 50%P1R16/Col scaffold group.Therefore,this study provides a promising strategy to develop multi-functional supramolecular peptides and a new method to topically administrate parathyroid hormone or parathyroid hormone related peptides for non-healing bone defects.展开更多
For the first time, ZrC-ZrB_2-SiC ceramic nanocomposites were successfully prepared by a single-source-precursor route, with allylhydridopolycarbosilane(AHPCS),triethylamine borane(TEAB),and bis(cyclopentadienyl) zirc...For the first time, ZrC-ZrB_2-SiC ceramic nanocomposites were successfully prepared by a single-source-precursor route, with allylhydridopolycarbosilane(AHPCS),triethylamine borane(TEAB),and bis(cyclopentadienyl) zirconium dichloride(Cp_2 ZrCl_2) as starting materials. The polymer-to-ceramic transformation and thermal behavior of obtained single-source precursor were characterized by means of Fourier transform infrared spectroscopy(FT-IR) and thermal gravimetric analysis(TGA). The results show that the precursor possesses a high ceramic yield about 85% at 1000 ℃.The phase composition and microstructure of formed ZrC-ZrB_2-SiC ceramics were investigated by means of X-ray diffraction(XRD) and high resolution transmission electron microscopy(HRTEM).Meanwhile, the weight loss and chemical composition of the resultant ZrC-ZrB_2-SiC nanocomposites were investigated after annealing at high temperature up to 1800 ℃. High temperature behavior with respect to decomposition as well as crystallization shows a promising high temperature stability of the formed ZrC-ZrB_2-SiC nanocomposites.展开更多
In order to enhance dielectric properties of polymer-derived SiC ceramics,a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane(AHPCS)and divinyl benzene(DVB)to form carbon...In order to enhance dielectric properties of polymer-derived SiC ceramics,a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane(AHPCS)and divinyl benzene(DVB)to form carbon-rich SiC.As expected,the free carbon contents of resultant SiC ceramics annealed at 1600℃are significantly enhanced from 6.62 wt%to 44.67 wt%.After annealing at 900-1600℃,the obtained carbon-rich SiC ceramics undergo phase separation from amorphous to crystalline feature where superfine SiC nanocrystals and turbostratic carbon networks are dispersed in an amorphous SiC(O)matrix.The dielectric properties and electromagnetic(EM)absorption performance of as-synthesized carbon-rich SiC ceramics are significantly improved by increasing the structural order and content of free carbon.For the 1600℃ ceramics mixed with paraffin wax,the minimum reflection coefficient(RCmin)reaches-56.8 dB at 15.2 GHz with the thickness of 1.51 mm and a relatively broad effective bandwidth(the bandwidth of RC values lower than-10 dB)of 4.43 GHz,indicating the excellent EM absorption performance.The carbon-rich SiC ceramics have to be considered as harsh environmental EM absorbers with excellent chemical stability,high temperature,and oxidation and corrosion resistance.展开更多
Aims Biodiversity patterns along elevational gradients have been well documented.Yet,the variations of biodiversity patterns along elevations and their underlying mechanisms are still unclear.Integrating multiple face...Aims Biodiversity patterns along elevational gradients have been well documented.Yet,the variations of biodiversity patterns along elevations and their underlying mechanisms are still unclear.Integrating multiple facets of biodiversity provides novel insights into the mechanisms for driving community assembly.In this study,species abundance information was incorporated into taxonomic and phylogenetic diversity to reveal the ecological and evolutionary forces of plant community assembly along an elevational gradient in subtropical forests.Methods We selected 17 woody plant plots along an elevational gradient from 270 to 1470 m in eastern China’s subtropical forests.Both presence-based and abundance-based measures of angiosperm species were used to quantify taxonomic alpha diversity,phylogenetic alpha diversity,phylogenetic relatedness,as well as taxonomic and phylogenetic dissimilarity among these plots.And the relations between these measures and climatic and topographic variables were analyzed.Important Findings For both abundance-weighted and unweighted measures,we observed an overall increasing pattern for taxonomic alpha diversity along elevation,and distance-decay trends of taxonomic and phylogenetic similarity with increased elevational distances.However,there were disparity patterns of phylogenetic alpha diversity between abundance-weighted and unweighted measures.For phylogenetic structure,there was no significant trend along elevation.Both topographical and microclimatic variables were main drivers of diversity patterns and phylogenetic structure.Compared with unweighted measures,abundance-weighted measures were strongly related with the slope and stand basal area.Overall,our results prove that deterministic processes mediated by local species abundance imprint on plant community composition along the elevational gradient.展开更多
基金supported by the National Natural Science Foundation of China(No.82372405,No.81871752)the Fundamental Research Funds for the Central Universities(NO.2042023kf0199)+2 种基金the Key Research and Development Program of Hubei Province(No:2022BCA052)the Key Research and Development Program of Wuhan City(No.2023020402010591)the Translational Medicine and Interdisciplinary Research Joint Fund of Zhongnan Hospital of Wuhan University(No.ZNJC202014).
文摘Supramolecular peptide nanofiber hydrogels are emerging biomaterials for tissue engineering,but it is difficult to fabricate multi-functional systems by simply mixing several short-motif-modified supramolecular peptides because relatively abundant motifs generally hinder nanofiber cross-linking or the formation of long nanofiber.Coupling bioactive factors to the assembling backbone is an ideal strategy to design multi-functional supramolecular peptides in spite of challenging synthesis and purification.Herein,a multi-functional supramolecular peptide,P1R16,is developed by coupling a bioactive factor,parathyroid hormone related peptide 1(PTHrP-1),to the basic supramolecular peptide RADA16-I via solid-phase synthesis.It is found that P1R16 self-assembles into long nanofibers and co-assembles with RADA16-I to form nanofiber hydrogels,thus coupling PTHrP-1 to hydrogel matrix.P1R16 nanofiber retains osteoinductive activity in a dose-dependent manner,and P1R16/RADA16-I nanofiber hydrogels promote osteogenesis,angiogenesis and osteoclastogenesis in vitro and induce multi-functionalized osteoregeneration by intramembranous ossification and bone remodeling in vivo when loaded to collagen(Col)scaffolds.Abundant red blood marrow formation,ideal osteointegration and adapted degradation are observed in the 50%P1R16/Col scaffold group.Therefore,this study provides a promising strategy to develop multi-functional supramolecular peptides and a new method to topically administrate parathyroid hormone or parathyroid hormone related peptides for non-healing bone defects.
基金National Natural Science Foundation of China (No. 51872246)Alexander von Humboldt Foundation, and Creative Research Foundation of Science and Technology on Thermo Structural Composite Materials Laboratory (No. 6142911040114) for financial supportthe National Key R&D Program of China (No. 2017YFB0703200)
文摘For the first time, ZrC-ZrB_2-SiC ceramic nanocomposites were successfully prepared by a single-source-precursor route, with allylhydridopolycarbosilane(AHPCS),triethylamine borane(TEAB),and bis(cyclopentadienyl) zirconium dichloride(Cp_2 ZrCl_2) as starting materials. The polymer-to-ceramic transformation and thermal behavior of obtained single-source precursor were characterized by means of Fourier transform infrared spectroscopy(FT-IR) and thermal gravimetric analysis(TGA). The results show that the precursor possesses a high ceramic yield about 85% at 1000 ℃.The phase composition and microstructure of formed ZrC-ZrB_2-SiC ceramics were investigated by means of X-ray diffraction(XRD) and high resolution transmission electron microscopy(HRTEM).Meanwhile, the weight loss and chemical composition of the resultant ZrC-ZrB_2-SiC nanocomposites were investigated after annealing at high temperature up to 1800 ℃. High temperature behavior with respect to decomposition as well as crystallization shows a promising high temperature stability of the formed ZrC-ZrB_2-SiC nanocomposites.
基金supported by the National Natural Science Foundation of China(No.51872246)Shenzhen Science and Technology Projects(JCYJ20180306172957494).
文摘In order to enhance dielectric properties of polymer-derived SiC ceramics,a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane(AHPCS)and divinyl benzene(DVB)to form carbon-rich SiC.As expected,the free carbon contents of resultant SiC ceramics annealed at 1600℃are significantly enhanced from 6.62 wt%to 44.67 wt%.After annealing at 900-1600℃,the obtained carbon-rich SiC ceramics undergo phase separation from amorphous to crystalline feature where superfine SiC nanocrystals and turbostratic carbon networks are dispersed in an amorphous SiC(O)matrix.The dielectric properties and electromagnetic(EM)absorption performance of as-synthesized carbon-rich SiC ceramics are significantly improved by increasing the structural order and content of free carbon.For the 1600℃ ceramics mixed with paraffin wax,the minimum reflection coefficient(RCmin)reaches-56.8 dB at 15.2 GHz with the thickness of 1.51 mm and a relatively broad effective bandwidth(the bandwidth of RC values lower than-10 dB)of 4.43 GHz,indicating the excellent EM absorption performance.The carbon-rich SiC ceramics have to be considered as harsh environmental EM absorbers with excellent chemical stability,high temperature,and oxidation and corrosion resistance.
基金This work was supported by the National Natural Science Foundation of China(32071538 to J.Z.and 31600343 to K.S.)Shanghai Natural Science Foundation(20ZR1418100 to J.Z.)East China Normal University to J.Z.and Z.Z.
文摘Aims Biodiversity patterns along elevational gradients have been well documented.Yet,the variations of biodiversity patterns along elevations and their underlying mechanisms are still unclear.Integrating multiple facets of biodiversity provides novel insights into the mechanisms for driving community assembly.In this study,species abundance information was incorporated into taxonomic and phylogenetic diversity to reveal the ecological and evolutionary forces of plant community assembly along an elevational gradient in subtropical forests.Methods We selected 17 woody plant plots along an elevational gradient from 270 to 1470 m in eastern China’s subtropical forests.Both presence-based and abundance-based measures of angiosperm species were used to quantify taxonomic alpha diversity,phylogenetic alpha diversity,phylogenetic relatedness,as well as taxonomic and phylogenetic dissimilarity among these plots.And the relations between these measures and climatic and topographic variables were analyzed.Important Findings For both abundance-weighted and unweighted measures,we observed an overall increasing pattern for taxonomic alpha diversity along elevation,and distance-decay trends of taxonomic and phylogenetic similarity with increased elevational distances.However,there were disparity patterns of phylogenetic alpha diversity between abundance-weighted and unweighted measures.For phylogenetic structure,there was no significant trend along elevation.Both topographical and microclimatic variables were main drivers of diversity patterns and phylogenetic structure.Compared with unweighted measures,abundance-weighted measures were strongly related with the slope and stand basal area.Overall,our results prove that deterministic processes mediated by local species abundance imprint on plant community composition along the elevational gradient.
