Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord inj...Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen＇s method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord.展开更多
Edaravone has been shown to delay neuronal apoptosis, thereby improving nerve function and the microenvironment after spinal cord injury. Edaravone can provide a favorable environment for theAa：eatment of spinal cord...Edaravone has been shown to delay neuronal apoptosis, thereby improving nerve function and the microenvironment after spinal cord injury. Edaravone can provide a favorable environment for theAa：eatment of spinal cord injury using Schwann cell transplantation. This study used rat models of complete spinal cord transection at T9. Six hours later, Schwann cells were transplanted in the head and tail ends of the injury site. Simultaneously, edaravone was injected through the caudal vein. Eight weeks later, the PKH-26-1abeled Schwann cells had survived and migrated to the center of the spinal cord injury region in rats after combined treatment with edaravone and Schwann cells. Moreover, the number of PKH-26-1abeled Schwann cells in the rat spinal cord was more than that in rats undergoing Schwann cell transplantation alone or rats without any treatment. Horseradish peroxidase retrograde tracing revealed that the number of horserad- ish peroxidase-positive nerve fibers was greater in rats treated with edaravone combined with Schwann cells than in rats with Schwann cell transplantation alone. The results demonstrated that lower extremity motor function and neurophysiological function were better in rats treated with edaravone and Schwann cells than in rats with Schwann cell transplantation only. These data confirmed that Schwann cell transplantation combined with edaravone injection promoted the regeneration of nerve fibers of rats with spinal cord injury and improved neurological function.展开更多
Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has b...Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has been proven in alloys.However,whether or not high entropy can also improve the irradiation resistance of ceramics,especially the mechanism therein still needs to be uncovered.In this work,the irradiation and helium(He)behaviors of zirconium carbide(ZrC)-based high-entropy ceramics(HECs),i.e.,(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C,were investigated and compared with those of ZrC under 540 keV He ion irradiation with a dose of 1×10^(17) cm^(−2) at room temperature and subsequent annealing.Both ZrC and(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C maintain lattice integrity after irradiation,while the irradiation-induced lattice expansion is smaller in(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C(0.78%)with highly thermodynamic stability than that in ZrC(0.91%).After annealing at 800℃,ZrC exhibits the residual _(0.2)0%lattice expansion,while(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C shows only 0.10%.Full recovery of the lattice parameter(a)is achieved for both ceramics after annealing at 1500℃.In addition,the high entropy in the meantime brings about the favorable structural evolution phenomena including smaller He bubbles that are evenly distributed without abnormal coarsening or aggregation,segregation,and shorter and sparser dislocation.The excellent irradiation resistance is related to the high-entropy-induced phase stability,sluggish diffusion of defects,and stress dispersion along with the production of vacancies by valence compensation.The present study indicates a high potential of high-entropy carbides in irradiation resistance applications.展开更多
Development of extramural health care for chronic wounds is still in its infancy in China,and thus it is urgent and vital to establish a correct concept and practicable principles.The authors reviewed recent domestic ...Development of extramural health care for chronic wounds is still in its infancy in China,and thus it is urgent and vital to establish a correct concept and practicable principles.The authors reviewed recent domestic and international literature and summarized the following treatment procedures and principles for extramural health care of chronic wounds.(1)The patient needs to do self-assessment of the wound by using available simple methods;(2)The patient consults with professional physicians or nurses on wound care to define the severity and etiology of the non-healing wound;(3)Professionals evaluate the existing treatment strategies;(4)Etiological treatments are given by professionals;(5)Patients buy needed dressings via the more convenient ways from pharmacies,e-commerce platform or others;(6)Professionals provide a standardized and reasonable therapeutic plan based on the patient's wound conditions;(7)Both professionals and the patient pay attention to complications to prevent adverse outcomes;(8)Professionals strengthen the public education on wound care and integrated rehabilitation.This review expected to provide new perspectives on the therapeutic strategies for chronic wounds in an extramural setting.展开更多
Objective:To investigate the relationship between renal function and clinical outcomes among patients with acute ST-segment elevation myocardial infarction (ASTEMI), who were treated with emergency percutaneous corona...Objective:To investigate the relationship between renal function and clinical outcomes among patients with acute ST-segment elevation myocardial infarction (ASTEMI), who were treated with emergency percutaneous coronary intervention (PCI). Methods: 420 patients hospitalized in Peking University First Hospital, diagnosed with ASTEMI treated with emergency (PCI) from January 2001 to June 2011 were enrolled in this study. Estimated glomerular filtration rate (eGFR) was used as a measure of renal function. We compared the clinical parameters and outcomes between ASTEMI patients combined renal insufficiency and the patients with normal renal function. Results:There was a significant increase in the concentrations of fibrinogen and D-Dimer (P<0.05) and a much higher morbidity of diabetes mellitus in the group of patients with chronic kidney disease (CKD; eGFR<60 ml/(min·1.73 m2)) (P<0.01). CKD (eGFR<60 ml/(min·1.73 m2)) was an independent predictor of in-hospital mortality for patients hospitalized with ASTEMI receiving PCI therapy rapidly (P=0.032, odds ratio (OR) 4.159, 95% confidence interval (CI) 1.127-15.346). Conclusions:Renal insufficiency is an independent predictor of in-hospital mortality for patients hospitalized with ASTEMI treated with primary PCI.展开更多
Coupled metronomes serve as a paradigmatic model for exploring the collective behaviors of com- plex dynamical systems, as well as a classical setup for classroom demonstrations of synchronization phenomena. Whereas p...Coupled metronomes serve as a paradigmatic model for exploring the collective behaviors of com- plex dynamical systems, as well as a classical setup for classroom demonstrations of synchronization phenomena. Whereas previous studies of metronome synchronization have been concentrating on symmetric coupling schemes, here we consider the asymmetric case by adopting the scheme of layered metronomes. Specifically, we place two metronomes on each layer, and couple two layers by placing one on top of the other. By varying the initial conditions of the metronomes and adjusting the friction between the two layers, a variety of synchronous patterns are observed in experiment, including the splay synchronization （SS） state, the generalized splay synchronization （GSS） state, the anti-phase synchronization （APS） state, the in-phase delay synchronization （IPDS） state, and the in-phase syn- chronization （IPS） state. In particular, the IPDS state, in which the metronomes on each layer are synchronized in phase but are of a constant phase delay to metronomes on the other layer, is observed for the first time. In addition, a new technique based on audio signals is proposed for pattern detection, which is more convenient and easier to apply than the existing acquisition techniques. Furthermore, a theoretical model is developed to explain the experimental observations, and is employed to explore the dynamical properties of the patterns, including the basin distributions and the pattern transitions. Our study sheds new lights on the collective behaviors of coupled metronomes, and the developed setup can be used in the classroom for demonstration purposes.展开更多
By a small-size complex network of coupled chaotic Hindmarsh-Rose circuits, we study experimen- tally the stability of network synchronization to the removal of shortcut links. It is shown that the removal of a single...By a small-size complex network of coupled chaotic Hindmarsh-Rose circuits, we study experimen- tally the stability of network synchronization to the removal of shortcut links. It is shown that the removal of a single shortcut link may destroy either completely or partially the network synchroniza- tion. Interestingly, when the network is partially desynchronized, it is found that the oscillators can be organized into different groups, with oscillators within each group being highly synchronized but are not for oscillators from different groups, showing the intriguing phenomenon of cluster synchro- nization. The experimental results are analyzed by the method of eigenvalue analysis, which implies that the formation of cluster synchronization is crucially dependent on the network symmetries. Our study demonstrates the observability of cluster synchronization in realistic systems, and indicates the feasibility of controlling network synchronization by adjusting network topology.展开更多
The deformation process of tailor rolled blank (TRB)is different from that of a monolithic blank as a result of the variable thickness in the rolling direction,and thus,the mechanism of the crack phenomenon needs to b...The deformation process of tailor rolled blank (TRB)is different from that of a monolithic blank as a result of the variable thickness in the rolling direction,and thus,the mechanism of the crack phenomenon needs to be further studied.The crack defect of TRB square box was studied by numerical simulation and stamping experiment.The stress state of TRB square box was elaborated.On this basis,the forming characteristics of TRB square box were summarized.The effects of blank size and blank holder force (BHF)on the thickness thinning of TRB were discussed.Finally,the mechanism.of the crack defect for TRB square box was revealed.Results indicate that non-uniformity is the most prominent characteristic during forming of TRB square box.The larger the blank size and BHF on the thinner side are,the more inclined TRB is to crack. Excessive BHF or insufficient BHF on the thicker side can also lead to the occurrence of the crack defect.BHF on the thinner side slightly greater than that on the thicker side (40 kN on the thinner side and 20 kN on the thicker side)is advantageous to restrict the excessive thickness thinning of TRB and acquire a better formability.The location inclined to crack for TRB square box is the round comer of the wall on the thinner side.展开更多
The dynamic study of radiation-induced defects with annealing is critical for the material design for nextgeneration nuclear energy systems.The native vacancy could affect the development of defects,which lacks study....The dynamic study of radiation-induced defects with annealing is critical for the material design for nextgeneration nuclear energy systems.The native vacancy could affect the development of defects,which lacks study.In the present work,the as-hot pressed ZrC_(1-x)(x=0,0.15,0.3)ceramics which comprised crystallites of a few microns in size with different amounts of carbon vacancies were irradiated by 540 ke V He^(2+)ions at room temperature with a fluence of 1×10^(17)/cm^(2).The radiation-induced lattice expansion was found to be a common phenomenon in a sequence of ZrC_(0.85)≥ZrC_(1.0)>ZrC_(0.7).Both X-ray and electron diffractions confirmed maintenance of structural integrity without amorphization after irradiation.Inside the irradiated region,only“black-dot”type defects,i.e.,clusters of point defects were observed while no helium-induced cavities,cracks,or extended dislocations were detected.The as-irradiated ZrC_(1-x)were then annealed at different high temperatures.Upon annealing at 800℃,very tiny helium-induced cavities were found to be generated and the crystal lattice recovered to a great extent,especially for the sub-stoichiometric samples.While annealed at 1500℃,all the samples almost fully recovered the crystal lattices close to those of as-hot pressed ones.Meanwhile,large cavities and extended dislocations were generated.With increasing amount of native carbon vacancies,the size of cavities increased while the length and density of extended dislocations decreased.Inverse changes of lattice parameters during irradiation and annealing processes have been interpreted by the kinetics of defects.Finally,the correlation between native vacancies and damage behavior is discussed.展开更多
文摘Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen＇s method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord.
文摘Edaravone has been shown to delay neuronal apoptosis, thereby improving nerve function and the microenvironment after spinal cord injury. Edaravone can provide a favorable environment for theAa：eatment of spinal cord injury using Schwann cell transplantation. This study used rat models of complete spinal cord transection at T9. Six hours later, Schwann cells were transplanted in the head and tail ends of the injury site. Simultaneously, edaravone was injected through the caudal vein. Eight weeks later, the PKH-26-1abeled Schwann cells had survived and migrated to the center of the spinal cord injury region in rats after combined treatment with edaravone and Schwann cells. Moreover, the number of PKH-26-1abeled Schwann cells in the rat spinal cord was more than that in rats undergoing Schwann cell transplantation alone or rats without any treatment. Horseradish peroxidase retrograde tracing revealed that the number of horserad- ish peroxidase-positive nerve fibers was greater in rats treated with edaravone combined with Schwann cells than in rats with Schwann cell transplantation alone. The results demonstrated that lower extremity motor function and neurophysiological function were better in rats treated with edaravone and Schwann cells than in rats with Schwann cell transplantation only. These data confirmed that Schwann cell transplantation combined with edaravone injection promoted the regeneration of nerve fibers of rats with spinal cord injury and improved neurological function.
基金supported by the National Natural Science Foundation of China(52022072,51972243,92060202 and 52202067)the National Key R&D Programs(2021YFB3701400)+2 种基金Hubei Provincial Natural Science Foundation of China(Distinguished Young Scholars 2022CFA042)Independent Innovation Projects of Hubei Longzhong Laboratory(2022ZZ-10)the Research Fund for Central Universities(2020IVB074 and 2021IVA094)。
基金financially supported by the National Natural Science Foundation of China(52032001,52102081,and 51532009)Shanghai Sailing Program(20YF1455500)+1 种基金Science and Technology Commission of Shanghai Municipality(16DZ2260603)Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(19DZ2290700).
文摘Excellent irradiation resistance is the basic property of nuclear materials to keep nuclear safety.The high-entropy design has great potential to improve the irradiation resistance of the nuclear materials,which has been proven in alloys.However,whether or not high entropy can also improve the irradiation resistance of ceramics,especially the mechanism therein still needs to be uncovered.In this work,the irradiation and helium(He)behaviors of zirconium carbide(ZrC)-based high-entropy ceramics(HECs),i.e.,(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C,were investigated and compared with those of ZrC under 540 keV He ion irradiation with a dose of 1×10^(17) cm^(−2) at room temperature and subsequent annealing.Both ZrC and(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C maintain lattice integrity after irradiation,while the irradiation-induced lattice expansion is smaller in(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C(0.78%)with highly thermodynamic stability than that in ZrC(0.91%).After annealing at 800℃,ZrC exhibits the residual _(0.2)0%lattice expansion,while(Zr_(0.2)Ti_(0.2)Nb_(0.2)Ta_(0.2)W_(0.2))C shows only 0.10%.Full recovery of the lattice parameter(a)is achieved for both ceramics after annealing at 1500℃.In addition,the high entropy in the meantime brings about the favorable structural evolution phenomena including smaller He bubbles that are evenly distributed without abnormal coarsening or aggregation,segregation,and shorter and sparser dislocation.The excellent irradiation resistance is related to the high-entropy-induced phase stability,sluggish diffusion of defects,and stress dispersion along with the production of vacancies by valence compensation.The present study indicates a high potential of high-entropy carbides in irradiation resistance applications.
基金Medical and Health Science and Technology Program of Zhejiang Province,China(grant number:2018247152)Key Laboratory of The Diagnosis and Treatment of Severe Trauma and Burn of Zhejiang Province,The Second Affiliated Hospital of Zhejiang University School of Medicine,China(grant number:2022K05).
文摘Development of extramural health care for chronic wounds is still in its infancy in China,and thus it is urgent and vital to establish a correct concept and practicable principles.The authors reviewed recent domestic and international literature and summarized the following treatment procedures and principles for extramural health care of chronic wounds.(1)The patient needs to do self-assessment of the wound by using available simple methods;(2)The patient consults with professional physicians or nurses on wound care to define the severity and etiology of the non-healing wound;(3)Professionals evaluate the existing treatment strategies;(4)Etiological treatments are given by professionals;(5)Patients buy needed dressings via the more convenient ways from pharmacies,e-commerce platform or others;(6)Professionals provide a standardized and reasonable therapeutic plan based on the patient's wound conditions;(7)Both professionals and the patient pay attention to complications to prevent adverse outcomes;(8)Professionals strengthen the public education on wound care and integrated rehabilitation.This review expected to provide new perspectives on the therapeutic strategies for chronic wounds in an extramural setting.
文摘Objective:To investigate the relationship between renal function and clinical outcomes among patients with acute ST-segment elevation myocardial infarction (ASTEMI), who were treated with emergency percutaneous coronary intervention (PCI). Methods: 420 patients hospitalized in Peking University First Hospital, diagnosed with ASTEMI treated with emergency (PCI) from January 2001 to June 2011 were enrolled in this study. Estimated glomerular filtration rate (eGFR) was used as a measure of renal function. We compared the clinical parameters and outcomes between ASTEMI patients combined renal insufficiency and the patients with normal renal function. Results:There was a significant increase in the concentrations of fibrinogen and D-Dimer (P<0.05) and a much higher morbidity of diabetes mellitus in the group of patients with chronic kidney disease (CKD; eGFR<60 ml/(min·1.73 m2)) (P<0.01). CKD (eGFR<60 ml/(min·1.73 m2)) was an independent predictor of in-hospital mortality for patients hospitalized with ASTEMI receiving PCI therapy rapidly (P=0.032, odds ratio (OR) 4.159, 95% confidence interval (CI) 1.127-15.346). Conclusions:Renal insufficiency is an independent predictor of in-hospital mortality for patients hospitalized with ASTEMI treated with primary PCI.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 11375109, and also by the Fundamental Research Funds for the Central Uni- versities under Grant No. GK201601001.
文摘Coupled metronomes serve as a paradigmatic model for exploring the collective behaviors of com- plex dynamical systems, as well as a classical setup for classroom demonstrations of synchronization phenomena. Whereas previous studies of metronome synchronization have been concentrating on symmetric coupling schemes, here we consider the asymmetric case by adopting the scheme of layered metronomes. Specifically, we place two metronomes on each layer, and couple two layers by placing one on top of the other. By varying the initial conditions of the metronomes and adjusting the friction between the two layers, a variety of synchronous patterns are observed in experiment, including the splay synchronization （SS） state, the generalized splay synchronization （GSS） state, the anti-phase synchronization （APS） state, the in-phase delay synchronization （IPDS） state, and the in-phase syn- chronization （IPS） state. In particular, the IPDS state, in which the metronomes on each layer are synchronized in phase but are of a constant phase delay to metronomes on the other layer, is observed for the first time. In addition, a new technique based on audio signals is proposed for pattern detection, which is more convenient and easier to apply than the existing acquisition techniques. Furthermore, a theoretical model is developed to explain the experimental observations, and is employed to explore the dynamical properties of the patterns, including the basin distributions and the pattern transitions. Our study sheds new lights on the collective behaviors of coupled metronomes, and the developed setup can be used in the classroom for demonstration purposes.
基金This work was supported by the National Natural Science Foundation of China under Grant No. 11375109 and the Fundamental Research Funds for the Central Universities under Grant No. GK201601001. Y.Z. Yu and X.G. Wang thank the support from the National Demonstration Center for pe rimental X-physics Education （Shaanxi Normal University）.
文摘By a small-size complex network of coupled chaotic Hindmarsh-Rose circuits, we study experimen- tally the stability of network synchronization to the removal of shortcut links. It is shown that the removal of a single shortcut link may destroy either completely or partially the network synchroniza- tion. Interestingly, when the network is partially desynchronized, it is found that the oscillators can be organized into different groups, with oscillators within each group being highly synchronized but are not for oscillators from different groups, showing the intriguing phenomenon of cluster synchro- nization. The experimental results are analyzed by the method of eigenvalue analysis, which implies that the formation of cluster synchronization is crucially dependent on the network symmetries. Our study demonstrates the observability of cluster synchronization in realistic systems, and indicates the feasibility of controlling network synchronization by adjusting network topology.
基金National Natural Science Foundation of China (51475086)Natural Science Foundation of Hebei Province (E2016501118)+1 种基金Fundamental Research Funds for the Central Universities (N172304036)Science and Technology Research Project for Higher School of Hebei Province (ZD2017315).
文摘The deformation process of tailor rolled blank (TRB)is different from that of a monolithic blank as a result of the variable thickness in the rolling direction,and thus,the mechanism of the crack phenomenon needs to be further studied.The crack defect of TRB square box was studied by numerical simulation and stamping experiment.The stress state of TRB square box was elaborated.On this basis,the forming characteristics of TRB square box were summarized.The effects of blank size and blank holder force (BHF)on the thickness thinning of TRB were discussed.Finally,the mechanism.of the crack defect for TRB square box was revealed.Results indicate that non-uniformity is the most prominent characteristic during forming of TRB square box.The larger the blank size and BHF on the thinner side are,the more inclined TRB is to crack. Excessive BHF or insufficient BHF on the thicker side can also lead to the occurrence of the crack defect.BHF on the thinner side slightly greater than that on the thicker side (40 kN on the thinner side and 20 kN on the thicker side)is advantageous to restrict the excessive thickness thinning of TRB and acquire a better formability.The location inclined to crack for TRB square box is the round comer of the wall on the thinner side.
基金financially supported by the National Natural Science Foundation of China(Nos.51532009,11575275 and 51872045)the Shanghai Sailing Program(No.20YF1455500)+1 种基金the Science and Technology Commission of Shanghai Municipality(Nos.16DZ2260603 and 18ZR1401400)the Shanghai Technical Platform for Testing and Characterization on Inorganic Materials(No.19DZ2290700)。
文摘The dynamic study of radiation-induced defects with annealing is critical for the material design for nextgeneration nuclear energy systems.The native vacancy could affect the development of defects,which lacks study.In the present work,the as-hot pressed ZrC_(1-x)(x=0,0.15,0.3)ceramics which comprised crystallites of a few microns in size with different amounts of carbon vacancies were irradiated by 540 ke V He^(2+)ions at room temperature with a fluence of 1×10^(17)/cm^(2).The radiation-induced lattice expansion was found to be a common phenomenon in a sequence of ZrC_(0.85)≥ZrC_(1.0)>ZrC_(0.7).Both X-ray and electron diffractions confirmed maintenance of structural integrity without amorphization after irradiation.Inside the irradiated region,only“black-dot”type defects,i.e.,clusters of point defects were observed while no helium-induced cavities,cracks,or extended dislocations were detected.The as-irradiated ZrC_(1-x)were then annealed at different high temperatures.Upon annealing at 800℃,very tiny helium-induced cavities were found to be generated and the crystal lattice recovered to a great extent,especially for the sub-stoichiometric samples.While annealed at 1500℃,all the samples almost fully recovered the crystal lattices close to those of as-hot pressed ones.Meanwhile,large cavities and extended dislocations were generated.With increasing amount of native carbon vacancies,the size of cavities increased while the length and density of extended dislocations decreased.Inverse changes of lattice parameters during irradiation and annealing processes have been interpreted by the kinetics of defects.Finally,the correlation between native vacancies and damage behavior is discussed.
