Peroxisome proliferator-activated receptors （PPAR） belong to the nuclear hormone receptor superfamily of ligand-dependent transcription factors. Recent results have shown that agonists of PPARy, such as troglitazone...Peroxisome proliferator-activated receptors （PPAR） belong to the nuclear hormone receptor superfamily of ligand-dependent transcription factors. Recent results have shown that agonists of PPARy, such as troglitazone （TGZ）, can inhibit cell proliferation and promote cell differentiation independent of PPARy. In the present study, we provide evidence that TGZ may bind directly to EGFR and trigger its signaling and internalization independent of PPARγ. Detailed studies revealed that prolonged incubation with TGZ effectively attenuated EGFR signaling by targeting the receptor to the endo-lysosomal degradation machinery. Although the extracellular signal-regulated kinasesignaling pathway was transiently activated by TGZ in EGFR overexpressing cancer cells, inhibition of EGF-induced Akt phosphorylation most likely accounted for the growth arrest of tumor cells caused by TGZ at pharmacologically achievable concentrations. Therefore, we have provided a new line of evidence indicating that TGZ inhibits cell pro- liferation by promoting EGFR degradation and attenuating Akt phosphorylation.展开更多
There are many problems in Social Internet of Things(IoTs),such as complex topology information,different degree of association between nodes and overlapping communities.The idea of set pair information grain computin...There are many problems in Social Internet of Things(IoTs),such as complex topology information,different degree of association between nodes and overlapping communities.The idea of set pair information grain computing and clustering is introduced to solve the above problems so as to accurately describe the similarity between nodes and fully explore the multi-community structure.A Set Pair Three-Way Overlapping Community Discovery Algorithm for Weighted Social Internet of Things(WSIoT-SPTOCD)is proposed.In the local network structure,which fully considers the topological information between nodes,the set pair connection degree is used to analyze the identity,difference and reverse of neighbor nodes.The similarity degree of different neighbor nodes is defined from network edge weight and node degree,and the similarity measurement method of set pair between nodes based on the local information structure is proposed.According to the number of nodes'neighbors and the connection degree of adjacent edges,the clustering intensity of nodes is defined,and an improved algorithm for initial value selection of k-means is proposed.The nodes are allocated according to the set pair similarity between nodes and different communities.Three-way community structures composed of a positive domain,boundary domain and negative domain are generated iteratively.Next,the overlapping node set is generated according to the calculation results of community node membership.Finally,experiments are carried out on artificial networks and real networks.The results show that WSIoT-SPTOCD performs well in terms of standardized mutual information,overlapping community modularity and F1.展开更多
Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required t...Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required to lower the height of center of gravity( COG) to enhance the stability and maneuverability. To properly handle these situations,a quadruped controller based on the central pattern generator( CPG) model,the discrete tracking differentiator( TD) and proportional-derivative( PD) sub-controllers is presented. The CPG is used to generate basic rhythmic motion for the quadruped robot. The discrete TD is not only creatively employed to implement the transition between two different rhythmic medium values of the CPG which results in the adjustment of the height of COG of the quadruped robot,but also modified to control the transition duration which enables the quadruped robot to achieve the stable transition. Additionally,two specific PD sub-controllers are constructed to adjust the oscillation amplitude of the CPG,so as to avoid the severe deviation in the transverse direction during transition locomotion. Finally,the controller is validated on a quadruped model. A tunnel with variable height is built for the quadruped model to travel through. The simulation demonstrates the severe deviation without the PD sub-controllers,and the reduced deviation with the PD sub-controllers.展开更多
Understanding the role of microbes in the solubility of cadmium(Cd) is of fundamental importance for remediation of Cd toxicity. The present study aimed to identify the microbes that involved in regulating Cd solubili...Understanding the role of microbes in the solubility of cadmium(Cd) is of fundamental importance for remediation of Cd toxicity. The present study aimed to identify the microbes that involved in regulating Cd solubility and to reveal possible mechanisms. Therefore,microbial communities were investigated through high-throughput sequencing approach, the molecular ecological network was constructed and metagenomes were predicted. Our results indicated that redox conditions affected both the solubility of soil Cd and the microbial communities. Anaerobic microbes, such as Anaerolineaceae, did not only play important roles in shaping the microbial community in soils, but might also be involved in regulating the Cd solubility. Two possible mechanisms that how Anaerolineaceae involved in Cd solubility are(1) Anaerolineaceae are important organic matter degraders under anoxic conditions and(2) Anaerolineaceae can co-exist with methane metabolism microbes, while methane metabolism promotes the precipitation of soluble Cd. Thus, application of Anaerolineaceae in bioremediation of soil Cadmium contamination is a potential approach. The study provided a novel insight into the role of microbial community in the regulation of Cd solubility under different redox conditions, and suggested a potential approach for the remediation of soil Cd contamination.展开更多
The wearable lower limb exoskeleton is a typical human-in-loop human–robot coupled system,which conducts natural and close cooperation with the human by recognizing human locomotion timely.Requiring subject-specific ...The wearable lower limb exoskeleton is a typical human-in-loop human–robot coupled system,which conducts natural and close cooperation with the human by recognizing human locomotion timely.Requiring subject-specific training is the main challenge of the existing approaches,and most methods have the problem of insufficient recognition.This paper proposes an integral subject-adaptive real-time Locomotion Mode Recognition(LMR)method based on GA-CNN for a lower limb exoskeleton system.The LMR method is a combination of Convolutional Neural Networks(CNN)and Genetic Algorithm(GA)-based multi-sensor information selection.To improve network performance,the hyper-parameters are optimized by Bayesian optimization.An exoskeleton prototype system with multi-type sensors and novel sensing-shoes is used to verify the proposed method.Twelve locomotion modes,which composed an integral locomotion system for the daily application of the exoskeleton,can be recognized by the proposed method.According to a series of experiments,the recognizer shows strong comprehensive abilities including high accuracy,low delay,and sufficient adaption to different subjects.展开更多
An electrically actuated lower extremity exoskeleton is developed, in which only the knee joint is actuated actively while other joints linked by elastic elements are actuated passively. This paper describes the criti...An electrically actuated lower extremity exoskeleton is developed, in which only the knee joint is actuated actively while other joints linked by elastic elements are actuated passively. This paper describes the critical design criteria and presents the process of design and calculation of the actuation system. A flexible physical Human-Robot-Interaction （pHR1） measurement device is designed and applied to detect the human movement, which comprises two force sensors and two gasbags attached to the inner surface of the connection cuff. An online adaptive pHRI minimization control strategy is proposed and implemented to drive the robotic exoskelcton system to follow the motion trajectory of human limb. The measured pHRI information is fused by the Variance Weighted Average （VWA） method. The Mean Square Values （MSV） of pHRI and control torque are utilized to evaluate the performance of the exoskeleton. To improve the comfort level and reduce energy consumption, the gravity compensation is taken into consideration when the control law is designed. Finally, practical experiments are performed on healthy users. Experimental results show that the proposed system can assist people to walk and the outlined control strategy is valid and effective.展开更多
Hybrid bonded/bolted(HBB) joint has been widely used in engineering practice because it can overcome the potential weakness of pure bonded and pure bolted joints. However, studies on HBB joint are still at the initial...Hybrid bonded/bolted(HBB) joint has been widely used in engineering practice because it can overcome the potential weakness of pure bonded and pure bolted joints. However, studies on HBB joint are still at the initial stage. In this paper, tensile properties of a composite–metal singlelap HBB joint was investigated experimentally. And a detailed finite element model(FEM) was established to simulate the tensile behavior of the joint. The model was verified by the experimental results. Then the damage propagation and load transfer mechanism were explored based on the FEM. The results show that the HBB joint can provide multi-load transmission paths and resist damage propagation in the adhesive. The HBB joint has higher strength and energy absorption capacity than the pure bonded joint. And the HBB joint has greater initial damage load and tensile stiffness than pure bolted joint. Adhesive fillets can obviously improve the tensile performances of the HBB joint. Lateral stiffness of the joint boundary and testing machine show obvious effects on tensile performances of single-lap hybrid joints.展开更多
Rheumatoid arthritis （RA） etiology and amelioration remains a challenge in modern therapeutics. Herein, we explored the synergistic effect of allogenic bone marrow stem cell （BMSC） translation and photodynamic tre...Rheumatoid arthritis （RA） etiology and amelioration remains a challenge in modern therapeutics. Herein, we explored the synergistic effect of allogenic bone marrow stem cell （BMSC） translation and photodynamic treatment of RA with tetra sulfonatophenyl porphyrin （TSPP） and TiO2 nanocomposites as a new strategy for RA theranostics. The translation of BMSCs with miRNAs into infected joints in long bones post-photodynamic therapy is helpful for treating and understanding RA pathophysiology. We observed that allogenic BMSC translation combined with TSPP-TiO2 nanocomposites can significantly （p 〈 0.01） lower the concentrations of serum biomarkers （tumor necrosis factor-α and interleukin-17） in a collagen induced arthritis （CIA） murine model, both in vitro and in vivo, as well as improve other parameters such as arthritis score, BMSC count, complete blood count, and numbers of platelets, red blood cells, and white blood cells. Moreover, a fluorescent TSPP in the feet or long bones and X-ray bioimaging of RA joints revealed the clinical efficacy of BMSCs combined with TSPP-TiO2 nanocomposites. Microarray data analysis illustrated that rnomir-375-3p and rno-mir-196b-3p were up-regulated by approximately 100-fold in the BMSCs of ameliorated RA post-photodynamic therapy with TSPP-TiO2 nanocomposites. Our study not only suggests a new approach for RA theranostics, but also helps in understanding RA pathophysiology.展开更多
Nowadays,photovoltaic effect has been widely studied in various ferroelectric materials due to its ap-plications as optoelectronic devices.In this work,with BiFeO_(3)(BFO)films as the photovoltaic materials,we report ...Nowadays,photovoltaic effect has been widely studied in various ferroelectric materials due to its ap-plications as optoelectronic devices.In this work,with BiFeO_(3)(BFO)films as the photovoltaic materials,we report the effects of Eu^(3+)doping content on the phase structure,ferroelectric and optical properties of BFO films grown on Ca_(0.96) Ce_(0.04) MnO_(3)/YAlO_(3)(001)substrate.We found that a small doping level of 0.05 could induce a phase change of BFO from tetragonal to rhombohedral,due to the shrinking of the lattice upon Eu^(3+)doping and the breaking of surface terrace structure induced by Ca_(0.96) Ce_(0.04) MnO_(3) layer.This results in a sharp band gap reduction from 3.30 eV to 2.60 eV,and a decrease in the coercivity of ferroelectric polarization switching.Based on these findings,we investigate the photovoltaic effects of ITO/Eu_(x) Bi_(1-x) FeO_(3)/Ca_(0.96) Ce_(0.04) MnO_(3) vertical capacitors.It is found that the short-circuit current density(J_(sc))decreases with increasing Eu^(3+)doping,whereas the open-circuit voltage(V_(oc))first increases to a level of 0.1 V and then decreases with further Eu^(3+)doping.This could be explained by the combined ef-fect of Schottky-junction and depolarization field on the photovoltaic process.Our research suggests that a moderate Eu^(3+)doping is helpful for enhancing the photovoltaic effect of BFO thin film devices.展开更多
Early diagnosis remains highly important for efficient cancer treatment, and hence, there is significant interest in the development of effective imaging strategies. This work reports a new multimodal bioimaging metho...Early diagnosis remains highly important for efficient cancer treatment, and hence, there is significant interest in the development of effective imaging strategies. This work reports a new multimodal bioimaging method for accurate and rapid diagnosis of cancer cells by introducing aqueous Fe^2＋ and Zn^2＋ ions into cancer cells （i.e., HeLa, U87, and HepG2 cancer cells）. We found that the biocompatible metal ions Fe^2＋ and Zn^2＋ forced the cancer cells to spontaneously synthesize fluorescent ZnO nanoclusters and magnetic Fe3O4 nanoclusters. These clusters could then be used for multimodal cancer imaging by combining fluorescence imaging with magnetic resonance imaging and computed tomography imaging. Meanwhile, for normal cells （i.e., L02） and tissues, neither fluorescence nor any other obvious difference could be detected between pre- and post-injection. This multimodal bioimaging strategy based on the in situ biosynthesized Zn＆Fe oxide nanoclusters might therefore be useful for early cancer diagnosis and therapy.展开更多
OBJECTIVE: To observe the effect of "Yang-warming and kidney essence-replenishing" herbal paste on cold-related asthma exacerbation. METHODS: One hundred and fifty one patients with moderate to severe persis...OBJECTIVE: To observe the effect of "Yang-warming and kidney essence-replenishing" herbal paste on cold-related asthma exacerbation. METHODS: One hundred and fifty one patients with moderate to severe persistent asthma were randomly divided into a treatment group (n=74) and a control group (n=69). Both groups were given basic treatment according to the Global Initiative for Asthma scheme. The treatment group was also treated with herbal paste in the winter. The frequency of asthma exacerbation, cold and cold-re-lated asthma exacerbation, scores of the asthma control test (ACT), and kidney-deficiency syndrome during the one-year follow-up in each group were recorded. RESULTS: Compared with the control group, the onset frequencies of catching cold, asthma exacerbation, cold-related asthma exacerbation, and kidney-deficiency syndrome score were significantly reduced. There was no significant difference in scores of ACT between the two groups. CONCLUSION: "Yang-warming and kidney essence-replenishing" herbal paste could reduce cold-related asthma exacerbation.展开更多
Composite-metal joints with a metal insert are one kind of connecting structure.In this paper,tensile experimental tests were carried out to investigate tensile properties of a compositemetal joint with a novel metal ...Composite-metal joints with a metal insert are one kind of connecting structure.In this paper,tensile experimental tests were carried out to investigate tensile properties of a compositemetal joint with a novel metal insert design.Finite element models of the joint were established,and strain distribution and tensile strength were analyzed.The numerical results are in good agreement with the experimental results.Results show that the joint failure is dominated by shear properties of the resin layer.Increasing the resin layer thickness in a certain range will improve the tensile strength of the joint,while increasing the radius of the fillet on the ending side of the metal insert will decrease the joint strength.Increasing the resin layer plasticity will improve the joint strength.The effect of the embedded depth of the metal insert can be ignored.展开更多
Nanostructured materials with abundant defect sinks show good radiation tolerance due to their efficient absorption of irradiation-induced interstitials and vacancies.However,the poor thermal stability and limited siz...Nanostructured materials with abundant defect sinks show good radiation tolerance due to their efficient absorption of irradiation-induced interstitials and vacancies.However,the poor thermal stability and limited size of such nanomaterials severely limit their practical applications.Herein,we report a novel flexible free-standing network-structured hybrid consisting of amorphous carbon encapsulated nickel nanocrystals anchored on a single-wall carbon nanotube scaffold with excellent radiation tolerance up to 5 dpa at 673 K and exceptional thermal stability up to 1073 K.The nano-scale Ni-SWCNT network with abundant Ni-SWCNT interfaces and grain boundaries provides effective sinks and fast transportation channels for defects,which effectively absorb irradiation-induced defects and improved the irradiation tolerance.Furthermore,the formation of a low-energy Ni-C interface and surface thermal grooves significantly reduces the system free energy and increased thermal stability.The amorphous carbon layer produces an external compressive radial stress that inhibits Ni grain boundaries from migrating,which greatly improves the thermal stability of the hybrid by pinning GBs at grooves between grains and facilitates the annihilation of irradiation-induced defects at the sinks.This work provides a new strategy to improve the thermal stability and radiation tolerance of nano-materials used in an irradiation environment.展开更多
文摘Peroxisome proliferator-activated receptors （PPAR） belong to the nuclear hormone receptor superfamily of ligand-dependent transcription factors. Recent results have shown that agonists of PPARy, such as troglitazone （TGZ）, can inhibit cell proliferation and promote cell differentiation independent of PPARy. In the present study, we provide evidence that TGZ may bind directly to EGFR and trigger its signaling and internalization independent of PPARγ. Detailed studies revealed that prolonged incubation with TGZ effectively attenuated EGFR signaling by targeting the receptor to the endo-lysosomal degradation machinery. Although the extracellular signal-regulated kinasesignaling pathway was transiently activated by TGZ in EGFR overexpressing cancer cells, inhibition of EGF-induced Akt phosphorylation most likely accounted for the growth arrest of tumor cells caused by TGZ at pharmacologically achievable concentrations. Therefore, we have provided a new line of evidence indicating that TGZ inhibits cell pro- liferation by promoting EGFR degradation and attenuating Akt phosphorylation.
文摘There are many problems in Social Internet of Things(IoTs),such as complex topology information,different degree of association between nodes and overlapping communities.The idea of set pair information grain computing and clustering is introduced to solve the above problems so as to accurately describe the similarity between nodes and fully explore the multi-community structure.A Set Pair Three-Way Overlapping Community Discovery Algorithm for Weighted Social Internet of Things(WSIoT-SPTOCD)is proposed.In the local network structure,which fully considers the topological information between nodes,the set pair connection degree is used to analyze the identity,difference and reverse of neighbor nodes.The similarity degree of different neighbor nodes is defined from network edge weight and node degree,and the similarity measurement method of set pair between nodes based on the local information structure is proposed.According to the number of nodes'neighbors and the connection degree of adjacent edges,the clustering intensity of nodes is defined,and an improved algorithm for initial value selection of k-means is proposed.The nodes are allocated according to the set pair similarity between nodes and different communities.Three-way community structures composed of a positive domain,boundary domain and negative domain are generated iteratively.Next,the overlapping node set is generated according to the calculation results of community node membership.Finally,experiments are carried out on artificial networks and real networks.The results show that WSIoT-SPTOCD performs well in terms of standardized mutual information,overlapping community modularity and F1.
基金Sponsored by the National Natural Science Foundation of China(Grant No.61375101)
文摘Since the quadruped robot possesses predominant environmental adaptability,it is expected to be employed in nature environments. In some situations,such as ice surface and tight space,the quadruped robot is required to lower the height of center of gravity( COG) to enhance the stability and maneuverability. To properly handle these situations,a quadruped controller based on the central pattern generator( CPG) model,the discrete tracking differentiator( TD) and proportional-derivative( PD) sub-controllers is presented. The CPG is used to generate basic rhythmic motion for the quadruped robot. The discrete TD is not only creatively employed to implement the transition between two different rhythmic medium values of the CPG which results in the adjustment of the height of COG of the quadruped robot,but also modified to control the transition duration which enables the quadruped robot to achieve the stable transition. Additionally,two specific PD sub-controllers are constructed to adjust the oscillation amplitude of the CPG,so as to avoid the severe deviation in the transverse direction during transition locomotion. Finally,the controller is validated on a quadruped model. A tunnel with variable height is built for the quadruped model to travel through. The simulation demonstrates the severe deviation without the PD sub-controllers,and the reduced deviation with the PD sub-controllers.
基金supported by the National Natural Science Foundation of China (Nos.31570113 and 41573072)the Scientific Research Fund of Hunan Provincial Education Department in China (No.17 K035)+1 种基金Chinese Postdoctoral Funding Planthe Central South University Postdoctoral Research Funding for D.M.(No.201699)
文摘Understanding the role of microbes in the solubility of cadmium(Cd) is of fundamental importance for remediation of Cd toxicity. The present study aimed to identify the microbes that involved in regulating Cd solubility and to reveal possible mechanisms. Therefore,microbial communities were investigated through high-throughput sequencing approach, the molecular ecological network was constructed and metagenomes were predicted. Our results indicated that redox conditions affected both the solubility of soil Cd and the microbial communities. Anaerobic microbes, such as Anaerolineaceae, did not only play important roles in shaping the microbial community in soils, but might also be involved in regulating the Cd solubility. Two possible mechanisms that how Anaerolineaceae involved in Cd solubility are(1) Anaerolineaceae are important organic matter degraders under anoxic conditions and(2) Anaerolineaceae can co-exist with methane metabolism microbes, while methane metabolism promotes the precipitation of soluble Cd. Thus, application of Anaerolineaceae in bioremediation of soil Cadmium contamination is a potential approach. The study provided a novel insight into the role of microbial community in the regulation of Cd solubility under different redox conditions, and suggested a potential approach for the remediation of soil Cd contamination.
文摘The wearable lower limb exoskeleton is a typical human-in-loop human–robot coupled system,which conducts natural and close cooperation with the human by recognizing human locomotion timely.Requiring subject-specific training is the main challenge of the existing approaches,and most methods have the problem of insufficient recognition.This paper proposes an integral subject-adaptive real-time Locomotion Mode Recognition(LMR)method based on GA-CNN for a lower limb exoskeleton system.The LMR method is a combination of Convolutional Neural Networks(CNN)and Genetic Algorithm(GA)-based multi-sensor information selection.To improve network performance,the hyper-parameters are optimized by Bayesian optimization.An exoskeleton prototype system with multi-type sensors and novel sensing-shoes is used to verify the proposed method.Twelve locomotion modes,which composed an integral locomotion system for the daily application of the exoskeleton,can be recognized by the proposed method.According to a series of experiments,the recognizer shows strong comprehensive abilities including high accuracy,low delay,and sufficient adaption to different subjects.
文摘An electrically actuated lower extremity exoskeleton is developed, in which only the knee joint is actuated actively while other joints linked by elastic elements are actuated passively. This paper describes the critical design criteria and presents the process of design and calculation of the actuation system. A flexible physical Human-Robot-Interaction （pHR1） measurement device is designed and applied to detect the human movement, which comprises two force sensors and two gasbags attached to the inner surface of the connection cuff. An online adaptive pHRI minimization control strategy is proposed and implemented to drive the robotic exoskelcton system to follow the motion trajectory of human limb. The measured pHRI information is fused by the Variance Weighted Average （VWA） method. The Mean Square Values （MSV） of pHRI and control torque are utilized to evaluate the performance of the exoskeleton. To improve the comfort level and reduce energy consumption, the gravity compensation is taken into consideration when the control law is designed. Finally, practical experiments are performed on healthy users. Experimental results show that the proposed system can assist people to walk and the outlined control strategy is valid and effective.
文摘Hybrid bonded/bolted(HBB) joint has been widely used in engineering practice because it can overcome the potential weakness of pure bonded and pure bolted joints. However, studies on HBB joint are still at the initial stage. In this paper, tensile properties of a composite–metal singlelap HBB joint was investigated experimentally. And a detailed finite element model(FEM) was established to simulate the tensile behavior of the joint. The model was verified by the experimental results. Then the damage propagation and load transfer mechanism were explored based on the FEM. The results show that the HBB joint can provide multi-load transmission paths and resist damage propagation in the adhesive. The HBB joint has higher strength and energy absorption capacity than the pure bonded joint. And the HBB joint has greater initial damage load and tensile stiffness than pure bolted joint. Adhesive fillets can obviously improve the tensile performances of the HBB joint. Lateral stiffness of the joint boundary and testing machine show obvious effects on tensile performances of single-lap hybrid joints.
基金This work is supported by National High-tech R＆D Program of China （No. 2015AA020502） and the National Natural Science Foundation of China （Nos. 81325011, 21327902 and 21175020）. M. S. acknowledges support from the NSF-PREM program （NSF Award DRM- 1523588）. H. J. acknowledges support from the Fundamental Research Funds for the Central Universities （No. 2242016K41023）, China.
文摘Rheumatoid arthritis （RA） etiology and amelioration remains a challenge in modern therapeutics. Herein, we explored the synergistic effect of allogenic bone marrow stem cell （BMSC） translation and photodynamic treatment of RA with tetra sulfonatophenyl porphyrin （TSPP） and TiO2 nanocomposites as a new strategy for RA theranostics. The translation of BMSCs with miRNAs into infected joints in long bones post-photodynamic therapy is helpful for treating and understanding RA pathophysiology. We observed that allogenic BMSC translation combined with TSPP-TiO2 nanocomposites can significantly （p 〈 0.01） lower the concentrations of serum biomarkers （tumor necrosis factor-α and interleukin-17） in a collagen induced arthritis （CIA） murine model, both in vitro and in vivo, as well as improve other parameters such as arthritis score, BMSC count, complete blood count, and numbers of platelets, red blood cells, and white blood cells. Moreover, a fluorescent TSPP in the feet or long bones and X-ray bioimaging of RA joints revealed the clinical efficacy of BMSCs combined with TSPP-TiO2 nanocomposites. Microarray data analysis illustrated that rnomir-375-3p and rno-mir-196b-3p were up-regulated by approximately 100-fold in the BMSCs of ameliorated RA post-photodynamic therapy with TSPP-TiO2 nanocomposites. Our study not only suggests a new approach for RA theranostics, but also helps in understanding RA pathophysiology.
基金supported by the National Natural Science Foundation of China (Nos.61974147 and 52031014)。
文摘Nowadays,photovoltaic effect has been widely studied in various ferroelectric materials due to its ap-plications as optoelectronic devices.In this work,with BiFeO_(3)(BFO)films as the photovoltaic materials,we report the effects of Eu^(3+)doping content on the phase structure,ferroelectric and optical properties of BFO films grown on Ca_(0.96) Ce_(0.04) MnO_(3)/YAlO_(3)(001)substrate.We found that a small doping level of 0.05 could induce a phase change of BFO from tetragonal to rhombohedral,due to the shrinking of the lattice upon Eu^(3+)doping and the breaking of surface terrace structure induced by Ca_(0.96) Ce_(0.04) MnO_(3) layer.This results in a sharp band gap reduction from 3.30 eV to 2.60 eV,and a decrease in the coercivity of ferroelectric polarization switching.Based on these findings,we investigate the photovoltaic effects of ITO/Eu_(x) Bi_(1-x) FeO_(3)/Ca_(0.96) Ce_(0.04) MnO_(3) vertical capacitors.It is found that the short-circuit current density(J_(sc))decreases with increasing Eu^(3+)doping,whereas the open-circuit voltage(V_(oc))first increases to a level of 0.1 V and then decreases with further Eu^(3+)doping.This could be explained by the combined ef-fect of Schottky-junction and depolarization field on the photovoltaic process.Our research suggests that a moderate Eu^(3+)doping is helpful for enhancing the photovoltaic effect of BFO thin film devices.
基金This work is supported by the National High-tech R＆D Program of China （No. 2015AA020502） and the National Natural Science Foundation of China （Nos. 81325011, 21327902 and 21175020）. M. S. acknowledges support from the NSF-PREM program （No, DRM-1523588）.
文摘Early diagnosis remains highly important for efficient cancer treatment, and hence, there is significant interest in the development of effective imaging strategies. This work reports a new multimodal bioimaging method for accurate and rapid diagnosis of cancer cells by introducing aqueous Fe^2＋ and Zn^2＋ ions into cancer cells （i.e., HeLa, U87, and HepG2 cancer cells）. We found that the biocompatible metal ions Fe^2＋ and Zn^2＋ forced the cancer cells to spontaneously synthesize fluorescent ZnO nanoclusters and magnetic Fe3O4 nanoclusters. These clusters could then be used for multimodal cancer imaging by combining fluorescence imaging with magnetic resonance imaging and computed tomography imaging. Meanwhile, for normal cells （i.e., L02） and tissues, neither fluorescence nor any other obvious difference could be detected between pre- and post-injection. This multimodal bioimaging strategy based on the in situ biosynthesized Zn＆Fe oxide nanoclusters might therefore be useful for early cancer diagnosis and therapy.
基金supported by the National Natural Science Foundation of China(22193042,22125110,21833010,22075285,21875251,21921001,and U21A2069)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(ZDBS-LY-SLH024)the Youth Innovation Promotion of Chinese Academy of Sciences(2020307)。
文摘OBJECTIVE: To observe the effect of "Yang-warming and kidney essence-replenishing" herbal paste on cold-related asthma exacerbation. METHODS: One hundred and fifty one patients with moderate to severe persistent asthma were randomly divided into a treatment group (n=74) and a control group (n=69). Both groups were given basic treatment according to the Global Initiative for Asthma scheme. The treatment group was also treated with herbal paste in the winter. The frequency of asthma exacerbation, cold and cold-re-lated asthma exacerbation, scores of the asthma control test (ACT), and kidney-deficiency syndrome during the one-year follow-up in each group were recorded. RESULTS: Compared with the control group, the onset frequencies of catching cold, asthma exacerbation, cold-related asthma exacerbation, and kidney-deficiency syndrome score were significantly reduced. There was no significant difference in scores of ACT between the two groups. CONCLUSION: "Yang-warming and kidney essence-replenishing" herbal paste could reduce cold-related asthma exacerbation.
基金the National Natural Science Foundation of China(No.11472024)for financial support
文摘Composite-metal joints with a metal insert are one kind of connecting structure.In this paper,tensile experimental tests were carried out to investigate tensile properties of a compositemetal joint with a novel metal insert design.Finite element models of the joint were established,and strain distribution and tensile strength were analyzed.The numerical results are in good agreement with the experimental results.Results show that the joint failure is dominated by shear properties of the resin layer.Increasing the resin layer thickness in a certain range will improve the tensile strength of the joint,while increasing the radius of the fillet on the ending side of the metal insert will decrease the joint strength.Increasing the resin layer plasticity will improve the joint strength.The effect of the embedded depth of the metal insert can be ignored.
基金financial support from the Ministry of Science and Technology of China(Nos.2017YFA0700702 and 2017YFA0700705)the National Natural Science Foundation of China(Nos.52073290,51927803,52130209,52188101,12075141,and 11427904)+1 种基金the Science Foundation of Shenyang National Laboratory for Materials Science,Distinguished Young Scholars Foundation of Liaoning Scientific Committee(2023JH6/100500004)Carbon Neutrality Foundation of Shenyang Scientific Committee(21-108-9-01).
文摘Nanostructured materials with abundant defect sinks show good radiation tolerance due to their efficient absorption of irradiation-induced interstitials and vacancies.However,the poor thermal stability and limited size of such nanomaterials severely limit their practical applications.Herein,we report a novel flexible free-standing network-structured hybrid consisting of amorphous carbon encapsulated nickel nanocrystals anchored on a single-wall carbon nanotube scaffold with excellent radiation tolerance up to 5 dpa at 673 K and exceptional thermal stability up to 1073 K.The nano-scale Ni-SWCNT network with abundant Ni-SWCNT interfaces and grain boundaries provides effective sinks and fast transportation channels for defects,which effectively absorb irradiation-induced defects and improved the irradiation tolerance.Furthermore,the formation of a low-energy Ni-C interface and surface thermal grooves significantly reduces the system free energy and increased thermal stability.The amorphous carbon layer produces an external compressive radial stress that inhibits Ni grain boundaries from migrating,which greatly improves the thermal stability of the hybrid by pinning GBs at grooves between grains and facilitates the annihilation of irradiation-induced defects at the sinks.This work provides a new strategy to improve the thermal stability and radiation tolerance of nano-materials used in an irradiation environment.
