The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making co...The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.展开更多
This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinf...This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinforced Plastics(CFRP).Different surface conditions were created by these treatments and simple Resin Pre-Coating(RPC)technique was further used to reduce the potential void defects at the root of those micro-cavities.Carbon Nanotubes(CNTs)were guided into the etched micro-cavities to construct quasi-Z-directional fiber bridging and form the“CNT-reinforced epoxy-pins”.The surface performance testing results imply that anodic oxidation of Al substrate created relatively even and continuous channels with higher hardness and better wettability among these treatments,which could provide quasi-vertical spaces for containing epoxy adhesive or CNTs.The single lap shear test results show combined treatments of anodic oxidation and upgraded RPC with CNTs technique on Al substrate yielded the highest bonding strength of 21.8 MPa(up to 243.3% greater than base strength).The constructed through-the-thickness“epoxy-pins”or“CNT-reinforced epoxy-pins”contributed to failure modes changing from complete debonding failure of Al substrate to peeled-off shallow fiber or delamination failure of CFRP panel.The combined treatments could be utilized to manufacture high-performance Al-CFRP composites for aviation industry application.展开更多
The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a r...The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a rat septic model was established by the cecal ligation and puncture (CLP).The rats were divided into control group,sepsis group and AC2-26 group.The rats in the AC2-26 group were intraperitoneally injected with AC2-26(1mg/kg)2h before CLP,and those in the control group and sepsis group were injected with the same volume of normal saline.The myocardial tissue was examined by hematoxylin and eosin (HE)staining and transmission electron microscopy (TEM).Furthermore,myocardial apoptosis was measured by terminal dUTP nick end-labeling (TUNEL)assay.In the in vitro study,H9C2cells were cultured and divided into three groups:control group,in which cells were only given the basic culture medium;LPS group,in which cells were treated with 10μg/mL LPS;AC2-26 group,in which cells were treated with 0.5μmol/L AC2-262h before 10μg/mL LPS was given.The apoptosis of H9C2 cells was detected by flow cytometry.The levels of lipoxin A4 receptor (LXA4),phosphoinositide3-kinase (PI3K)and protein kinase B (PKB or AKT)protein were measured by Western blotting, the activity of NF-KB and the level of TNF-α by ELISA and the activities of caspase-3/8by using the caspase activity kits.The in vivo study showed that the myocardial pathological damage and myocardial ultrastructural damage were significantly alleviated and the myocardial apoptosis significantly decreased in the AC2-26 group as compared with the sepsis group (P<0.05 for all). The in vivo study revealed that the apoptosis of H9C2 cells was profoundly ameliorated in the AC2-26 group relative to the sepsis group (P<0.05).The protein expression levels of LXA4 were significantly up-regulated,and those of PI3K and AKT prominently down-regulated in the AC2-26 group when compared with those in the LPS group (P<0.05 for all).The activity of NF-κB was greatly inhibited and the level of TNF-α markedly decreased in the AC2-26 group as compared with those in the LPS group (P<0.05 for all).AC2-26 treatment also significantly suppressed the activities of caspase-3/8 in H9C2 cells.In conclusion,these findings suggest that AC2-26 may alleviate the sepsis-induced cardiomyocyte apoptosis in vivo and in vivo through the LXA4/PI3K/ AKT signaling pathway.展开更多
Brassinosteroids(BRs) are potent regulators of photosynthesis and crop yield in agricultural crops;however,the mechanism by which BRs increase photosynthesis is not fully understood.Here,we show that foliar applicatio...Brassinosteroids(BRs) are potent regulators of photosynthesis and crop yield in agricultural crops;however,the mechanism by which BRs increase photosynthesis is not fully understood.Here,we show that foliar application of 24-epibrassinolide(EBR) resulted in increases in CO 2 assimilation,hydrogen peroxide(H 2 O 2) accumulation,and leaf area in cucumber.H 2 O 2 treatment induced increases in CO 2 assimilation whilst inhibition of the H 2 O 2 accumulation by its generation inhibitor or scavenger completely abolished EBR-induced CO 2 assimilation.Increases of light harvesting due to larger leaf areas in EBR-and H 2 O 2-treated plants were accompanied by increases in the photochemical efficiency of photosystem II(Φ PSII) and photochemical quenching coefficient(q P).EBR and H 2 O 2 both activated carboxylation efficiency of ribulose-1,5-bisphosphate oxygenase/carboxylase(Rubisco) from analysis of CO 2 response curve and in vitro measurement of Rubisco activities.Moreover,EBR and H 2 O 2 increased contents of total soluble sugar,sucrose,hexose,and starch,followed by enhanced activities of sugar metabolism such as sucrose phosphate synthase,sucrose synthase,and invertase.Interestingly,expression of transcripts of enzymes involved in starch and sugar utilization were inhibited by EBR and H 2 O 2.However,the effects of EBR on carbohydrate metabolisms were reversed by the H 2 O 2 generation inhibitor diphenyleneodonium(DPI) or scavenger dimethylthiourea(DMTU) pretreatment.All of these results indicate that H 2 O 2 functions as a secondary messenger for EBR-induced CO 2 assimilation and carbohydrate metabolism in cucumber plants.Our study confirms that H 2 O 2 mediates the regulation of photosynthesis by BRs and suggests that EBR and H 2 O 2 regulate Calvin cycle and sugar metabolism via redox signaling and thus increase the photosynthetic potential and yield of crops.展开更多
To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high ...To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.展开更多
A series of La2O3-promoted Li-Mn/WO3/TiO2 catalysts were prepared by varying the concentration of La2O3 promoter.The effect of La2O3 promoter on its properties and catalytic performance for OCM was characterized with ...A series of La2O3-promoted Li-Mn/WO3/TiO2 catalysts were prepared by varying the concentration of La2O3 promoter.The effect of La2O3 promoter on its properties and catalytic performance for OCM was characterized with XRD,FT-IR,O2-TPD,Raman,CO2-TPD,H2-TPR,XPS and CH4-TPSR,The results show that all the La2O3-promoted Li-Mn/WO3/TiO2 catalysts possess a larger amount of strong basic sites and more abundant chemisorbed oxygen species in comparison with Li-Mn/WO3/TiO2,which is beneficial to OCM reaction.Furthermore,La2O3 promoter can enhance the mobility of the oxygen species and the Mn species redox ability,which can also be favorable for the improvement of the catalytic performance for OCM,Due to the optimal synergistic interaction of these factors,5 wt%La2O3-Li-Mn/WO3/TiO2 exhibits the best performance among all the catalysts,on which the highest C2 yield of 19.2% is achieved at 750℃.展开更多
基金co-supported by the Foundation of Shanghai Astronautics Science and Technology Innovation,China(No.SAST2022-114)the National Natural Science Foundation of China(No.62303378),the National Natural Science Foundation of China(Nos.124B2031,12202281)the Foundation of China National Key Laboratory of Science and Technology on Test Physics&Numerical Mathematics,China(No.08-YY-2023-R11)。
文摘The problem of collision avoidance for non-cooperative targets has received significant attention from researchers in recent years.Non-cooperative targets exhibit uncertain states and unpredictable behaviors,making collision avoidance significantly more challenging than that for space debris.Much existing research focuses on the continuous thrust model,whereas the impulsive maneuver model is more appropriate for long-duration and long-distance avoidance missions.Additionally,it is important to minimize the impact on the original mission while avoiding noncooperative targets.On the other hand,the existing avoidance algorithms are computationally complex and time-consuming especially with the limited computing capability of the on-board computer,posing challenges for practical engineering applications.To conquer these difficulties,this paper makes the following key contributions:(A)a turn-based(sequential decision-making)limited-area impulsive collision avoidance model considering the time delay of precision orbit determination is established for the first time;(B)a novel Selection Probability Learning Adaptive Search-depth Search Tree(SPL-ASST)algorithm is proposed for non-cooperative target avoidance,which improves the decision-making efficiency by introducing an adaptive-search-depth mechanism and a neural network into the traditional Monte Carlo Tree Search(MCTS).Numerical simulations confirm the effectiveness and efficiency of the proposed method.
基金supported financially by the National Natural Science Foundations of China(No.52102115)the Natural Science Foundation of Sichuan Province,China(No.2025HJRC0019)+1 种基金the Basalt Fiber and Composite Key Laboratory of Sichuan Province,China(No.XXKFJJ202308)Shock and Vibration of Engineering Materials and Structures Key Lab of Sichuan Province,China(No.23kfgk06)。
文摘This study focused on the various surface treatments of grinding,Na OH etching,HCl pickling,micro-arc oxidation and anodic oxidation to strengthen adhesive bonding joint of Aluminum(Al)substrate and Carbon Fiber Reinforced Plastics(CFRP).Different surface conditions were created by these treatments and simple Resin Pre-Coating(RPC)technique was further used to reduce the potential void defects at the root of those micro-cavities.Carbon Nanotubes(CNTs)were guided into the etched micro-cavities to construct quasi-Z-directional fiber bridging and form the“CNT-reinforced epoxy-pins”.The surface performance testing results imply that anodic oxidation of Al substrate created relatively even and continuous channels with higher hardness and better wettability among these treatments,which could provide quasi-vertical spaces for containing epoxy adhesive or CNTs.The single lap shear test results show combined treatments of anodic oxidation and upgraded RPC with CNTs technique on Al substrate yielded the highest bonding strength of 21.8 MPa(up to 243.3% greater than base strength).The constructed through-the-thickness“epoxy-pins”or“CNT-reinforced epoxy-pins”contributed to failure modes changing from complete debonding failure of Al substrate to peeled-off shallow fiber or delamination failure of CFRP panel.The combined treatments could be utilized to manufacture high-performance Al-CFRP composites for aviation industry application.
基金the Hubei Provincial Natural Science Foundation(No.2018CFC847)the Hubei Cancer Hospital Foundation(No.2015C11).
文摘The aim of the present study was to explore the effects of annexin A1(ANXA1) mimetic peptide AC2-26 on sepsis-induced cardiomyocyte apoptosis in vivo and in vitro and the underlying mechanisms.In the in vivo study,a rat septic model was established by the cecal ligation and puncture (CLP).The rats were divided into control group,sepsis group and AC2-26 group.The rats in the AC2-26 group were intraperitoneally injected with AC2-26(1mg/kg)2h before CLP,and those in the control group and sepsis group were injected with the same volume of normal saline.The myocardial tissue was examined by hematoxylin and eosin (HE)staining and transmission electron microscopy (TEM).Furthermore,myocardial apoptosis was measured by terminal dUTP nick end-labeling (TUNEL)assay.In the in vitro study,H9C2cells were cultured and divided into three groups:control group,in which cells were only given the basic culture medium;LPS group,in which cells were treated with 10μg/mL LPS;AC2-26 group,in which cells were treated with 0.5μmol/L AC2-262h before 10μg/mL LPS was given.The apoptosis of H9C2 cells was detected by flow cytometry.The levels of lipoxin A4 receptor (LXA4),phosphoinositide3-kinase (PI3K)and protein kinase B (PKB or AKT)protein were measured by Western blotting, the activity of NF-KB and the level of TNF-α by ELISA and the activities of caspase-3/8by using the caspase activity kits.The in vivo study showed that the myocardial pathological damage and myocardial ultrastructural damage were significantly alleviated and the myocardial apoptosis significantly decreased in the AC2-26 group as compared with the sepsis group (P<0.05 for all). The in vivo study revealed that the apoptosis of H9C2 cells was profoundly ameliorated in the AC2-26 group relative to the sepsis group (P<0.05).The protein expression levels of LXA4 were significantly up-regulated,and those of PI3K and AKT prominently down-regulated in the AC2-26 group when compared with those in the LPS group (P<0.05 for all).The activity of NF-κB was greatly inhibited and the level of TNF-α markedly decreased in the AC2-26 group as compared with those in the LPS group (P<0.05 for all).AC2-26 treatment also significantly suppressed the activities of caspase-3/8 in H9C2 cells.In conclusion,these findings suggest that AC2-26 may alleviate the sepsis-induced cardiomyocyte apoptosis in vivo and in vivo through the LXA4/PI3K/ AKT signaling pathway.
基金Project supported by the National Basic Research Program (973) of China (No. 2009CB119000)the National Natural Science Foundation of China (No. 30972033)the Program for New Century Excellent Talents in University,China
文摘Brassinosteroids(BRs) are potent regulators of photosynthesis and crop yield in agricultural crops;however,the mechanism by which BRs increase photosynthesis is not fully understood.Here,we show that foliar application of 24-epibrassinolide(EBR) resulted in increases in CO 2 assimilation,hydrogen peroxide(H 2 O 2) accumulation,and leaf area in cucumber.H 2 O 2 treatment induced increases in CO 2 assimilation whilst inhibition of the H 2 O 2 accumulation by its generation inhibitor or scavenger completely abolished EBR-induced CO 2 assimilation.Increases of light harvesting due to larger leaf areas in EBR-and H 2 O 2-treated plants were accompanied by increases in the photochemical efficiency of photosystem II(Φ PSII) and photochemical quenching coefficient(q P).EBR and H 2 O 2 both activated carboxylation efficiency of ribulose-1,5-bisphosphate oxygenase/carboxylase(Rubisco) from analysis of CO 2 response curve and in vitro measurement of Rubisco activities.Moreover,EBR and H 2 O 2 increased contents of total soluble sugar,sucrose,hexose,and starch,followed by enhanced activities of sugar metabolism such as sucrose phosphate synthase,sucrose synthase,and invertase.Interestingly,expression of transcripts of enzymes involved in starch and sugar utilization were inhibited by EBR and H 2 O 2.However,the effects of EBR on carbohydrate metabolisms were reversed by the H 2 O 2 generation inhibitor diphenyleneodonium(DPI) or scavenger dimethylthiourea(DMTU) pretreatment.All of these results indicate that H 2 O 2 functions as a secondary messenger for EBR-induced CO 2 assimilation and carbohydrate metabolism in cucumber plants.Our study confirms that H 2 O 2 mediates the regulation of photosynthesis by BRs and suggests that EBR and H 2 O 2 regulate Calvin cycle and sugar metabolism via redox signaling and thus increase the photosynthetic potential and yield of crops.
基金supported by the National Key R&D Program of China(2019YFA0110600 and 2019YFA0110601)National Natural Science Foundation of China(Nos.51603134,51903178,51803134,and 51703141)+1 种基金Sichuan Province’s Science and Technology Planning Project(No.2016GZ0350)the Postgraduate Course Construction Project of Sichuan University(No.2017KCSJ036)and for their financial support.
文摘To overcome the ever-growing organic pollutions in the water system,abundant efforts have been dedicated to fabricating efficient Fenton-like carbon catalysts.However,the rational design of carbon catalysts with high intrinsic activity remains a long-term goal.Herein,we report a new N-molecule-assisted self-catalytic carbonization process in augmenting the intrinsic Fenton-like activity of metal-organic-framework-derived carbon hybrids.During carbonization,the N-molecules provide alkane/ammonia gases and the formed iron nanocrystals act as the in situ catalysts,which result in the elaborated formation of carbon nanotubes(in situ chemical vapor deposition from alkane/iron catalysts)and micro-/meso-porous structures(ammonia gas etching).The obtained catalysts exhibited with abundant Fe/Fe-Nx/pyridinic-N active species,micro-/meso-porous structures,and conductive carbon nanotubes.Consequently,the catalysts exhibit high efficiency toward the degradation of different organic pollutions,such as bisphenol A,methylene blue,and tetracycline.This study not only creates a new pathway for achieving highly active Fenton-like carbon catalysts but also takes a step toward the customized production of advanced carbon hybrids for diverse energy and environmental applications.
基金supported by the Petro China Innovation Foundation(2016D-5007-0506)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA09030101).
文摘A series of La2O3-promoted Li-Mn/WO3/TiO2 catalysts were prepared by varying the concentration of La2O3 promoter.The effect of La2O3 promoter on its properties and catalytic performance for OCM was characterized with XRD,FT-IR,O2-TPD,Raman,CO2-TPD,H2-TPR,XPS and CH4-TPSR,The results show that all the La2O3-promoted Li-Mn/WO3/TiO2 catalysts possess a larger amount of strong basic sites and more abundant chemisorbed oxygen species in comparison with Li-Mn/WO3/TiO2,which is beneficial to OCM reaction.Furthermore,La2O3 promoter can enhance the mobility of the oxygen species and the Mn species redox ability,which can also be favorable for the improvement of the catalytic performance for OCM,Due to the optimal synergistic interaction of these factors,5 wt%La2O3-Li-Mn/WO3/TiO2 exhibits the best performance among all the catalysts,on which the highest C2 yield of 19.2% is achieved at 750℃.
