Geopolymers are an important class of materials with potential applications because of their heat resistance,flame resistance,environmental friendliness,and possibilities of being transformed into ceramic matrix compo...Geopolymers are an important class of materials with potential applications because of their heat resistance,flame resistance,environmental friendliness,and possibilities of being transformed into ceramic matrix composites at low cost.However,the low mechanical properties as well as the intrinsic brittleness limit their technological implementations,and it is necessary to enhance the mechanical properties of geopolymers by adopting various kinds of reinforcements.In this work,therefore,two⁃dimensional continuous carbon fiber(Cf)reinforced phosphate⁃based geopolymer composites(Cf/geopolymer)were prepared through ultrasonic⁃assisted impregnation method.Effects of acetone treatment and high⁃temperature treatment on the properties of Cf/geopolymer composites were studied by X⁃ray photoelectron spectroscopy(XPS),X⁃ray diffraction(XRD),and scanning electron microscopy(SEM).Results of the study proved that acetone treatment plays a key role in ameliorating the interfacial interaction between Cf and phosphate matrix,which can thus enhance the mechanical properties of Cf/geopolymer composites.The Cf/geopolymer composites prepared by acetone⁃treated Cf had a flexural strength of 156.1 MPa and an elastic modulus of 39.7 GPa in Y direction.Moreover,an additional Sol⁃SiO2 re⁃impregnation treatment could further enhance the mechanical properties of the acetone⁃treated Cf/geopolymer composites by repairing the cracks and filling the pores.The results in this paper not only provide insights into the surface modification of Cf,but also report a facile and low⁃cost preparation route for Cf/geopolymer composites with potential applications in aerospace and defense technology.展开更多
Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium cast...Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium castaneum.Yet the biological function of TcCTL14 remains unclear.In this study,TcCTL14 exhibiting typical motif and domain of CTL was cloned from T.castaneum.The expression pattern analysis showed that TcCTL14 was highly expressed in late pupae and central nervous system,and was upregulated after treatment with Escherichia coli and Staphylococcus aureus,respectively.Analysis of binding affinity revealed that recombinant TcCTL14 not only could bind to lipopolysaccharide and peptidoglycan in a dose-dependent fashion,but possibly could bind to and agglutinate different bacteria in a Ca2+-dependent fashion.Knockdown of TcCTL14 before injection with bacteria led to the downregulation of nuclear factor-κB transcription factors of Toll/IMD and 4 antimicrobial peptides.Knockdown of TcCTL14 also caused suppressed metamorphosis,reduced fecundity,and delayed embryogenesis of T.castaneum.Further observation discovered that knockdown of TcCTL14 inhibited the development of ovaries and embryos.The detection of signaling pathways revealed that TcCTL14 may be involved in metamorphosis and fecundity by impacting 20-hydroxyecdysone and vitellogenin,respectively.Overall,these results indicate that TcCTL14 may contribute to immune response by agglutination or regulating the expression of antimicrobial peptides by the Toll/IMD pathway,and is required for T.castaneum development including metamorphosis,fecundity,and embryogenesis.These findings will improve the functional cognition of PRR CTL in insects and provide the new strategy for pest control.展开更多
基金National Natural Science Foundation of China(Grant Nos.51872063,51832002 and 51621091)the Natural Science Foundation of Heilongjiang Province(Grant No.YQ2019E002)the National Key Research and Development Program of China(Grant No.2017YFB0703200)。
摘要Geopolymers are an important class of materials with potential applications because of their heat resistance,flame resistance,environmental friendliness,and possibilities of being transformed into ceramic matrix composites at low cost.However,the low mechanical properties as well as the intrinsic brittleness limit their technological implementations,and it is necessary to enhance the mechanical properties of geopolymers by adopting various kinds of reinforcements.In this work,therefore,two⁃dimensional continuous carbon fiber(Cf)reinforced phosphate⁃based geopolymer composites(Cf/geopolymer)were prepared through ultrasonic⁃assisted impregnation method.Effects of acetone treatment and high⁃temperature treatment on the properties of Cf/geopolymer composites were studied by X⁃ray photoelectron spectroscopy(XPS),X⁃ray diffraction(XRD),and scanning electron microscopy(SEM).Results of the study proved that acetone treatment plays a key role in ameliorating the interfacial interaction between Cf and phosphate matrix,which can thus enhance the mechanical properties of Cf/geopolymer composites.The Cf/geopolymer composites prepared by acetone⁃treated Cf had a flexural strength of 156.1 MPa and an elastic modulus of 39.7 GPa in Y direction.Moreover,an additional Sol⁃SiO2 re⁃impregnation treatment could further enhance the mechanical properties of the acetone⁃treated Cf/geopolymer composites by repairing the cracks and filling the pores.The results in this paper not only provide insights into the surface modification of Cf,but also report a facile and low⁃cost preparation route for Cf/geopolymer composites with potential applications in aerospace and defense technology.
基金supported by grants from the National Natural Science Foundation of China to Bin Li(Grant number:31872970 and 32170521).
摘要Evidence is accumulating that pattern recognition receptor(PRR)C-type lectins(CTL)play essential roles in recognition of pathogens.TcCTL14(accession no.TC00871)contains the most domains among all CTL of Tribolium castaneum.Yet the biological function of TcCTL14 remains unclear.In this study,TcCTL14 exhibiting typical motif and domain of CTL was cloned from T.castaneum.The expression pattern analysis showed that TcCTL14 was highly expressed in late pupae and central nervous system,and was upregulated after treatment with Escherichia coli and Staphylococcus aureus,respectively.Analysis of binding affinity revealed that recombinant TcCTL14 not only could bind to lipopolysaccharide and peptidoglycan in a dose-dependent fashion,but possibly could bind to and agglutinate different bacteria in a Ca2+-dependent fashion.Knockdown of TcCTL14 before injection with bacteria led to the downregulation of nuclear factor-κB transcription factors of Toll/IMD and 4 antimicrobial peptides.Knockdown of TcCTL14 also caused suppressed metamorphosis,reduced fecundity,and delayed embryogenesis of T.castaneum.Further observation discovered that knockdown of TcCTL14 inhibited the development of ovaries and embryos.The detection of signaling pathways revealed that TcCTL14 may be involved in metamorphosis and fecundity by impacting 20-hydroxyecdysone and vitellogenin,respectively.Overall,these results indicate that TcCTL14 may contribute to immune response by agglutination or regulating the expression of antimicrobial peptides by the Toll/IMD pathway,and is required for T.castaneum development including metamorphosis,fecundity,and embryogenesis.These findings will improve the functional cognition of PRR CTL in insects and provide the new strategy for pest control.