Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant ...Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant plasmids pET28a(+)EccslH28,pET28a(+)EccslH41,pET28a(+)EccslH122 and pET28a(+)EccslH184 were prepared and transformed into E.coli to express the recombinant enzymes.Then analysis on enzymatic properties showed that T50 of the recombinant enzymes was increased from 10 min for EccslHt2 to 90 min for EccslH28 and 40 min for EccslH41 at 70℃,while their optimum pH value and pH stability were not affected,which proved that the introduction of disulfide bond improved the thermal stability ofβ-1,4 glucanase.展开更多
The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation p...The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation process unexpectedly yields a series of novel organic molecules containing C-N bonds.Interestingly,the synthesis method does not require any external transition-metals catalysis,and photo-/electro-catalysis.Additionally,when the new compound 1b is added as a third component to a well-known binary system of PM6:Y6,the efficiency of the organic solar cell is significantly improved,resulting in an outstanding efficiency of 18.0%,which is one of the highest values reported to date for PM6:Y6-based ternary organic solar cells.展开更多
The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete,which allows the internal forces to be transferred to the reinforcement during the ...The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete,which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements.The modification of the concrete composition,with the introduction of recycled aggregate from construction and demolition waste(CDW),affects the steel-concrete interface and can modify the bonding stress,which is also influenced by the type and diameter of the bar used.In this work,the influence of the recycled fine aggregate(RFA)and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test.Conventional concrete and recycled concrete,with RFA replacement level of 25%,were produced.Two types of steel rebars(i.e.,plain and deformed)with diameters of 10.0 and 16.0 mm were considered in this paper.The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate,but this trend is influenced by the diameter of the bar used.The use of ribbed bars modifies the stress bon-slip behavior,with an increase in the average bond strength,which is also observed with the reduction of the diameter of the bar.展开更多
Recent years have witnessed breakthroughs in the study of zigzag hydrocarbon belts.However,the synthesis of heterocycle-containing zigzag molecular belts remains very rare and challenging despite their interesting str...Recent years have witnessed breakthroughs in the study of zigzag hydrocarbon belts.However,the synthesis of heterocycle-containing zigzag molecular belts remains very rare and challenging despite their interesting structures and potential applications in chemistry and materials science.Here,we report the expeditious construction of a highly strained belt[4]arene[4](1,4-dihydropyridine)structure using the fjords-stitching strategy.The synthesis comprised four-fold abnormal m-bromination of four Npivaloylaniline units and Pd_(2)(dba)_(3)/4-Me_(2)NC_(6)H_(4)Pt Bu_(2)-catalyzed intramolecular C-N bond-forming reactions.Subsequent functionalization through Narylations produced a variety of tetraza-embedded octahydrobelt[8]arenes.Further oxidation of p-methoxyphenyl-substituted belt[4]arene[4](1,4-dihydropyridine)with Ag[Al(O^(t)Bu^(F))^(4)]yielded a singlet diradical dication N-doped zigzag belt.展开更多
基金Supported by the National Key Research and Development Plan of China(2019YFC1905902,2019YFC1905900)Key Research and Development Plan in Shandong Province(2020CXGC010603,2021ZDSYS10,2022CXGC020206)+2 种基金"Open Competition Mechanism"Project of Qilu University of Technology(Shandong Academy of Sciences)(2022JBZ01-06)Taishan Industry Leading Talent Program(tscy20180103)National Natural Science Foundation of China(31801527)。
文摘Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant plasmids pET28a(+)EccslH28,pET28a(+)EccslH41,pET28a(+)EccslH122 and pET28a(+)EccslH184 were prepared and transformed into E.coli to express the recombinant enzymes.Then analysis on enzymatic properties showed that T50 of the recombinant enzymes was increased from 10 min for EccslHt2 to 90 min for EccslH28 and 40 min for EccslH41 at 70℃,while their optimum pH value and pH stability were not affected,which proved that the introduction of disulfide bond improved the thermal stability ofβ-1,4 glucanase.
基金supported by the National Natural Science Foundation of China(U21A20331)the National Science Fund for Distinguished Young Scholars(21925506)the Zhejiang Provincial Natural Science Foundation of China(LQ22E030013)。
文摘The construction of C-N bonds is of great importance in the fields of biology,medicine,chemistry and materials science.Here,the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation process unexpectedly yields a series of novel organic molecules containing C-N bonds.Interestingly,the synthesis method does not require any external transition-metals catalysis,and photo-/electro-catalysis.Additionally,when the new compound 1b is added as a third component to a well-known binary system of PM6:Y6,the efficiency of the organic solar cell is significantly improved,resulting in an outstanding efficiency of 18.0%,which is one of the highest values reported to date for PM6:Y6-based ternary organic solar cells.
基金The authors would like to thank the CAPES which sponsored the first author.
文摘The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete,which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements.The modification of the concrete composition,with the introduction of recycled aggregate from construction and demolition waste(CDW),affects the steel-concrete interface and can modify the bonding stress,which is also influenced by the type and diameter of the bar used.In this work,the influence of the recycled fine aggregate(RFA)and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test.Conventional concrete and recycled concrete,with RFA replacement level of 25%,were produced.Two types of steel rebars(i.e.,plain and deformed)with diameters of 10.0 and 16.0 mm were considered in this paper.The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate,but this trend is influenced by the diameter of the bar used.The use of ribbed bars modifies the stress bon-slip behavior,with an increase in the average bond strength,which is also observed with the reduction of the diameter of the bar.
基金We thank the National Natural Science Foundation of China(grant nos.22050005,21732004,and 21821001)the Tsinghua University Initiative Scientific Research Program(grant no.2019Z07L01004)for generous financial support.
文摘Recent years have witnessed breakthroughs in the study of zigzag hydrocarbon belts.However,the synthesis of heterocycle-containing zigzag molecular belts remains very rare and challenging despite their interesting structures and potential applications in chemistry and materials science.Here,we report the expeditious construction of a highly strained belt[4]arene[4](1,4-dihydropyridine)structure using the fjords-stitching strategy.The synthesis comprised four-fold abnormal m-bromination of four Npivaloylaniline units and Pd_(2)(dba)_(3)/4-Me_(2)NC_(6)H_(4)Pt Bu_(2)-catalyzed intramolecular C-N bond-forming reactions.Subsequent functionalization through Narylations produced a variety of tetraza-embedded octahydrobelt[8]arenes.Further oxidation of p-methoxyphenyl-substituted belt[4]arene[4](1,4-dihydropyridine)with Ag[Al(O^(t)Bu^(F))^(4)]yielded a singlet diradical dication N-doped zigzag belt.
