Covalent triazine-based frameworks（CTFs） are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used f...Covalent triazine-based frameworks（CTFs） are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used for CTFs,aromatic nitriles,were obtained by cyanation using nontoxic potassium hexacyanoferrate（Ⅱ） in place of commonly used toxic cyanides.Then,the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride.A series of CTFs was synthesized,and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m^2/g.Among the synthesized CTFs,CTF_（DCP） exhibited excellent CO_2 adsorption properties,with a CO_2 uptake of 225 mg/g at 0℃.展开更多
Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separa...Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3（BTC）2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.展开更多
Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation...Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.展开更多
A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigon...A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigonal planar ligand, which links three di-copper paddlewheel units giving rise to a Pt304 net.展开更多
Objective： To develop a novel scaffolding method for the copolymers poly lactide-co-glycolide acid （PLGA） to construct a three-dimensional （3-D） scaffold and explore its biocompatibility through culturing Schwann...Objective： To develop a novel scaffolding method for the copolymers poly lactide-co-glycolide acid （PLGA） to construct a three-dimensional （3-D） scaffold and explore its biocompatibility through culturing Schwann cells （SCs） on it. Methods： The 3-D scaffolds were made by means of melt spinning, extension and weaving. The queueing discipline of the micro-channels were observed under a scanning electronic microscope （SEM）.The sizes of the micropores and the factors of porosity were also measured. Sciatic nerves were harvested from 3-day-old Sprague Dawley （SD） rats for culture of SCs. SCs were separated, purified, and then implanted on PLGA scaffolds, gelatin sponge and poly-L-lysine （PLL）-coated tissue culture poly-styrene （TCPS） were used as biomaterial and cell-supportive controls, respectively. The effect of PLGA on the adherence, proliferation and apoptosis of SCs were examined in vitro in comparison with gelatin sponge and TCPS. Results： The micro-channels arrayed in parallel manners, and the pore sizes of the channels were uniform. No significant difference was found in the activity of Schwann cells cultured on PLGA and those on TCPS （P〉0.05）, and the DNA of PLGA scaffolds was not damaged. Conclusion： The 3-D scaffolds developed in this study have excellent structure and biocompatibility, which may be taken as a novel scaffold candidate for nerve-tissue engineering.展开更多
Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise ...Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise molecular mechanisms underlying fertilization are largely unknown.The two most dramatic changes taking place in the zygote immediately after fertilization are:(i) a sharp increase of intracellular Ca2+ that initiates at the sperm interaction site and traverses the egg cytoplasm as a wave,and(ii) the concomitant dynamic rearrangement of the actin cytoskeleton.Traditionally,this has been studied most extensively in the sea urchin eggs,but another echinoderm,starfish,whose eggs are much bigger and transparent,has facilitated experimental approaches using microinjection and fluorescent imaging methodologies.Thus in starfish,it has been shown that the sperm-induced Ca2+ increase in the fertilized egg can be recapitulated by several Ca2+ -evoking second messengers,namely inositol 1,4,5-trisphosphate(InsP3) ,cyclic ADP-ribose(cADPr) and nicotinic acid adenine dinucleotide phosphate(NAADP) ,which may play distinct roles in the generation and propagation of the Ca2+ waves.Interestingly,it has also been found that the dynamic rearrangement of the actin cytoskeleton in the fertilized eggs plays pivotal roles in guiding monospermic sperm entry and in the fine modulation of the intracellular Ca2+ signaling.As it is well known that Ca2+ regulates the structure of the actin cytoskeleton,our finding that Ca2+ signaling can be reciprocally affected by the state of the actin cytoskeleton raises an intriguing possibility that actin and Ca2+ signaling may form a'positive feedback loop'that accelerates the downstream events of fertilization.Perturbation of the cortical actin networks also inhibits cortical granules exocytosis.Polymerizing actin bundles also compose the'acrosome process,'a tubular structure protruding from the head of fertilizing sperm. Hence,actin,which is one of the most strictly conserved proteins in eukaryotes,modulates almost all major aspects of fertilization.展开更多
基金supported by the National Natural Science Foundation of China(21373202,21525315)~~
文摘Covalent triazine-based frameworks（CTFs） are important microporous materials with a wide range of applications.Here,we demonstrate an environmentally benign and economic synthetic pathway to CTFs.The monomers used for CTFs,aromatic nitriles,were obtained by cyanation using nontoxic potassium hexacyanoferrate（Ⅱ） in place of commonly used toxic cyanides.Then,the CTFs were synthesized by trimerization of the corresponding cyano monomers in molten zinc chloride.A series of CTFs was synthesized,and the highest Brunauer-Emmett-Teller surface area measured in this series was 2404 m^2/g.Among the synthesized CTFs,CTF_（DCP） exhibited excellent CO_2 adsorption properties,with a CO_2 uptake of 225 mg/g at 0℃.
基金supported by the National Natural Science Foundation of China (21203017)the Open Fund of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences(N-11-3)+1 种基金the Program for Liaoning Excellent Talents in University (LNET)the Fundamental Research Funds for the Central Universities (DC201502020304)~~
文摘Metal organic frameworks（MOFs） are an important platform for heterogeneous catalysts.Although MOFs with a smaller particle size exhibit better catalytic performance because of less diffusion limitations,their separation and recycling after catalytic reactions are difficult.The integration of MOFs with magnetic nanoparticles could facilitate their recovery and separation.Especially,the shell thickness of the core-shell structured composites is controllable.In this study,amino-functionalized Fe3O4@Cu3（BTC）2 was fabricated by a stepwise assembly method and its catalytic performance in Knoevenagel condensation was investigated.The results demonstrated that the magnetic hybrid material exhibited a core-shell structure,with a shell thickness of about 2 00 nm.Furthermore,it not only exhibited high catalytic activity,but remarkably,it could also be easily recovered magnetically and recycled without obvious loss of catalytic efficiency after three cycles.
文摘Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.
基金supported by the U.S. Department of Energy (DOE Grants DE-FC36-07GO17033)the Welch Foundation (A-1725)+1 种基金supported by the National Science Foundation/Department of Energy under grant number NSF/CHE-0822838supported by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
文摘A metal-organic framework （MOF） has been obtained by using a linker extension strategy. Three di-anions of 4-（3,5-dimethyl- 1H-pyrazol-4-yl）-benzoic acid coordinate to three Cu（I） ions forming an extended trigonal planar ligand, which links three di-copper paddlewheel units giving rise to a Pt304 net.
文摘Objective： To develop a novel scaffolding method for the copolymers poly lactide-co-glycolide acid （PLGA） to construct a three-dimensional （3-D） scaffold and explore its biocompatibility through culturing Schwann cells （SCs） on it. Methods： The 3-D scaffolds were made by means of melt spinning, extension and weaving. The queueing discipline of the micro-channels were observed under a scanning electronic microscope （SEM）.The sizes of the micropores and the factors of porosity were also measured. Sciatic nerves were harvested from 3-day-old Sprague Dawley （SD） rats for culture of SCs. SCs were separated, purified, and then implanted on PLGA scaffolds, gelatin sponge and poly-L-lysine （PLL）-coated tissue culture poly-styrene （TCPS） were used as biomaterial and cell-supportive controls, respectively. The effect of PLGA on the adherence, proliferation and apoptosis of SCs were examined in vitro in comparison with gelatin sponge and TCPS. Results： The micro-channels arrayed in parallel manners, and the pore sizes of the channels were uniform. No significant difference was found in the activity of Schwann cells cultured on PLGA and those on TCPS （P〉0.05）, and the DNA of PLGA scaffolds was not damaged. Conclusion： The 3-D scaffolds developed in this study have excellent structure and biocompatibility, which may be taken as a novel scaffold candidate for nerve-tissue engineering.
文摘Since the first demonstration of sperm entry into the fertilized eggs of Mediterranean sea urchin Paracentrotus lividus by Hertwig(1876),enormous progress and insights have been made on this topic.However,the precise molecular mechanisms underlying fertilization are largely unknown.The two most dramatic changes taking place in the zygote immediately after fertilization are:(i) a sharp increase of intracellular Ca2+ that initiates at the sperm interaction site and traverses the egg cytoplasm as a wave,and(ii) the concomitant dynamic rearrangement of the actin cytoskeleton.Traditionally,this has been studied most extensively in the sea urchin eggs,but another echinoderm,starfish,whose eggs are much bigger and transparent,has facilitated experimental approaches using microinjection and fluorescent imaging methodologies.Thus in starfish,it has been shown that the sperm-induced Ca2+ increase in the fertilized egg can be recapitulated by several Ca2+ -evoking second messengers,namely inositol 1,4,5-trisphosphate(InsP3) ,cyclic ADP-ribose(cADPr) and nicotinic acid adenine dinucleotide phosphate(NAADP) ,which may play distinct roles in the generation and propagation of the Ca2+ waves.Interestingly,it has also been found that the dynamic rearrangement of the actin cytoskeleton in the fertilized eggs plays pivotal roles in guiding monospermic sperm entry and in the fine modulation of the intracellular Ca2+ signaling.As it is well known that Ca2+ regulates the structure of the actin cytoskeleton,our finding that Ca2+ signaling can be reciprocally affected by the state of the actin cytoskeleton raises an intriguing possibility that actin and Ca2+ signaling may form a'positive feedback loop'that accelerates the downstream events of fertilization.Perturbation of the cortical actin networks also inhibits cortical granules exocytosis.Polymerizing actin bundles also compose the'acrosome process,'a tubular structure protruding from the head of fertilizing sperm. Hence,actin,which is one of the most strictly conserved proteins in eukaryotes,modulates almost all major aspects of fertilization.
