Neuronal plasticity,the brain's ability to adapt structurally and functionally,is essential for learning,memory,and recovery from injuries.In neurodegenerative diseases such as Alzheimer's disease and Parkinso...Neuronal plasticity,the brain's ability to adapt structurally and functionally,is essential for learning,memory,and recovery from injuries.In neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease,this plasticity is disrupted,leading to cognitive and motor deficits.This review explores the mechanisms of neuronal plasticity and its effect on Alzheimer's disease and Parkinson's disease.Alzheimer's disease features amyloid-beta plaques and tau tangles that impair synaptic function,while Parkinson's disease involves the loss of dopaminergic neurons affecting motor control.Enhancing neuronal plasticity offers therapeutic potential for these diseases.A systematic literature review was conducted using databases such as PubMed,Scopus,and Google Scholar,focusing on studies of neuronal plasticity in Alzheimer's disease and Parkinson's disease.Data synthesis identified key themes such as synaptic mechanisms,neurogenesis,and therapeutic strategies,linking molecular insights to clinical applications.Results highlight that targeting synaptic plasticity mechanisms,such as long-term potentiation and long-term depression,shows promise.Neurotrophic factors,advanced imaging techniques,and molecular tools(e.g.,clustered regularly interspaced short palindromic repeats and optogenetics)are crucial in understanding and enhancing plasticity.Current therapies,including dopamine replacement,deep brain stimulation,and lifestyle interventions,demonstrate the potential to alleviate symptoms and improve outcomes.In conclusion,enhancing neuronal plasticity through targeted therapies holds significant promise for treating neurodegenerative diseases.Future research should integrate multidisciplinary approaches to fully harness the therapeutic potential of neuronal plasticity in Alzheimer's disease and Parkinson's disease.展开更多
Sleep is a fundamental biological process essential for maintaining brain function,cognitive performance,and overall health.Despite over a century of research,the mechanisms underlying sleep homeostasis-the process by...Sleep is a fundamental biological process essential for maintaining brain function,cognitive performance,and overall health.Despite over a century of research,the mechanisms underlying sleep homeostasis-the process by which the need for sleep accumulates during wakefulness and dissipates during sleep-remain incompletely understood.This article explores the latest advancements in sleep research,focusing on the role of synaptic plasticity in sleep homeostasis,as illuminated by Sawada et al.(2024).展开更多
Nonlinear static procedures are widely adopted in structural engineering practice for seismic performance assessment due to their simplicity and computational efficiency.However,their reliability depends heavily on ho...Nonlinear static procedures are widely adopted in structural engineering practice for seismic performance assessment due to their simplicity and computational efficiency.However,their reliability depends heavily on how the nonlinear behaviour of structural components is represented.The recent earthquakes in Albania(2019)and Türkiye(2023)have underscored the need for accurate assessment techniques,particularly for older reinforced concrete buildings with poor detailing.This study quantifies the discrepancies between default and user-defined component modelling in pushover analysis of pre-modern reinforced concrete structures,analysing two representative low-and mid-rise reinforced concrete frame buildings.The lumped plasticity approach incorporates moment-rotation relationships derived from actual member properties and reinforcement configurations,while the distributed plasticity approach uses software-generated default properties based on modern codes.Results show that the distributed plasticity models systematically overestimate both the strength and the deformation capacity by up to 35%compared to lumped plasticity models,especially in buildings with poor detailing and low concrete strength.These findings demonstrate that default software procedures,widely used in practice but not validated for pre-modern structures,produce dangerously unconservative seismic performance estimates.The study provides quantitative evidence of the critical need for tailored modelling strategies that reflect the actual conditions of the existing building stock.展开更多
The capacity of the central nervous system for structural plasticity and regeneration is commonly believed to show a decreasing progression from“small and simple”brains to the larger,more complex brains of mammals.H...The capacity of the central nervous system for structural plasticity and regeneration is commonly believed to show a decreasing progression from“small and simple”brains to the larger,more complex brains of mammals.However,recent findings revealed that some forms of neural plasticity can show a reverse trend.Although plasticity is a well-preserved,transversal feature across the animal world,a variety of cell populations and mechanisms seem to have evolved to enable structural modifications to take place in widely different brains,likely as adaptations to selective pressures.Increasing evidence now indicates that a trade-off has occurred between regenerative(mostly stem cell–driven)plasticity and developmental(mostly juvenile)remodeling,with the latter primarily aimed not at brain repair but rather at“sculpting”the neural circuits based on experience.In particular,an evolutionary trade-off has occurred between neurogenic processes intended to support the possibility of recruiting new neurons throughout life and the different ways of obtaining new neurons,and between the different brain locations in which plasticity occurs.This review first briefly surveys the different types of plasticity and the complexity of their possible outcomes and then focuses on recent findings showing that the mammalian brain has a stem cell–independent integration of new neurons into pre-existing(mature)neural circuits.This process is still largely unknown but involves neuronal cells that have been blocked in arrested maturation since their embryonic origin(also termed“immature”or“dormant”neurons).These cells can then restart maturation throughout the animal's lifespan to become functional neurons in brain regions,such as the cerebral cortex and amygdala,that are relevant to high-order cognition and emotions.Unlike stem cell–driven postnatal/adult neurogenesis,which significantly decreases from small-brained,short-living species to large-brained ones,immature neurons are particularly abundant in large-brained,long-living mammals,including humans.The immature neural cell populations hosted in these complex brains are an interesting example of an“enlarged road”in the phylogenetic trend of plastic potential decreases commonly observed in the animal world.The topic of dormant neurons that covary with brain size and gyrencephaly represents a prospective turning point in the field of neuroplasticity,with important translational outcomes.These cells can represent a reservoir of undifferentiated neurons,potentially granting plasticity within the high-order circuits subserving the most sophisticated cognitive skills that are important in the growing brains of young,healthy individuals and are frequently affected by debilitating neurodevelopmental and degenerative disorders.展开更多
Regenerative capacity of the central nervous system(CNS)is unevenly distributed among vertebrates.While most mammalian species including humans elicit limited repair following CNS injury or disease,highly regenerative...Regenerative capacity of the central nervous system(CNS)is unevenly distributed among vertebrates.While most mammalian species including humans elicit limited repair following CNS injury or disease,highly regenerative vertebrates including urodele amphibians and teleost fish spontaneously reverse CNS damage.Teletost zebrafish(danio rerio)are tropical freshwater fish that proved to be an excellent vertebrate model of successful CNS regeneration.Differential neuronal,glial,and immune injury responses underlie disparate injury outcomes between highly regenerative zebrafish and poorly regenerative mammals.This article describes complications associated with neuronal repair following spinal cord injury(SCI)in poorly regenerative mammals and highlights intersecting modes of plasticity and regeneration in highly regenerative zebrafish(Figures 1 and 2).Comparative approaches evaluating immunoglial SCI responses were recently reviewed elsewhere(Reyes and Mokalled,2024).展开更多
Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°...Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.展开更多
Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its prec...Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its precise mechanism in treating post-CHF cognitive dysfunction remains unclear.This study systematically investigates XJQ’s effects on post-CHF cognitive dysfunction and the underlying mechanisms.The components of XJQ were identified through liquid chromatography-mass spectrometry.CHF was induced in rats via ligation of the left anterior descending coronary artery,followed by six weeks of XJQ treatment.Cardiac function was evaluated through echocardiography and hemodynamic parameters,while cognitive function was assessed using Morris water maze(MWM)and open field tests(OFT).XJQ treatment enhanced both cardiac and cognitive functions in CHF rats.Network pharmacology identified 12 core active components of XJQ and indicated its effect on cognitive dysfunction involved regulating synapses,inflammation,and phosphodiesterase 4(PDE4)-dependent cyclic adenosine monophosphate(cAMP)signaling.XJQ inhibited microglial and astrocyte activation,decreased proinflammatory cytokines,and mitigated neuronal damage.Notably,XJQ promoted synaptic repair and dendritic growth by downregulating PDE4 and upregulating cAMP,protein kinase A(PKA),cAMP-response element binding protein(CREB),brain-derived neurotrophic factor(BDNF),PSD95,and synapsin I levels.Molecular docking and Bio-layer interferometry assays confirmed direct binding of quercetin,kaempferol,isorhamnetin,and darutoside to PDE4.In conclusion,XJQ alleviates neuroinflammation and enhances synaptic plasticity to improve cognitive dysfunction in CHF rats via the PDE4/cAMP/PKA/CREB signaling pathway.These findings provide valuable insight into the heart-brain axis.展开更多
In rock engineering,natural cracks in rock masses subjected to external loads tend to initiate and propagate,leading to potential safety hazards.To investigate the effect of cracking behavior on the mechanical propert...In rock engineering,natural cracks in rock masses subjected to external loads tend to initiate and propagate,leading to potential safety hazards.To investigate the effect of cracking behavior on the mechanical properties of rocks,the cracking processes of pre-cracked rocks have been extensively studied using numerical modeling methods.The peridynamics(PD)exhibits advantages over other numerical methods due to the absence of the requirements for remeshing and external crack growth criterion.However,for modeling pre-cracked rock cracking processes under impact,current PD implementations lack generally applicable rock constitutive models and impact contact models,which leads to difficulties in determining rock material parameters and efficiently calculating impact loads.This paper proposes a non-ordinary state-based peridynamics(NOSBPD)modeling method integrating the Drucker-Prager(DP)plasticity model and an efficient contact model to address the above problems.In the proposed method,the Drucker-Prager plasticity model is integrated into the NOSBPD,thereby equipping NOSBPD with the capability to accurately characterize the nonlinear stress-strain relationship inherent in rocks.An efficient contact model between particles and meshes is designed to calculate the impact loads,which is essentially a coupling method of PD with the finite element method(FEM).The effectiveness of the proposed NOSBPD modeling method is verified by comparison with other numerical methods and experiments.Experimental results indicate that the proposed method can effectively and accurately predict the 3D cracking processes of pre-cracked cracks under impact loading,and the maximum principal stress is the key driver behind wing crack formation in pre-cracked rocks.展开更多
This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A tempe...This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A temperature-indexed Concrete Damage Plasticity(CDP)framework incorporating bond–slip effects was developed in Abaqus to capture both global stress–strain responses and localized damage evolution.Uniaxial compression tests on thermally exposed cylinders provided residual strength data and failure observations for model calibration and validation.Results demonstrated a distinct two-stage degradation regime:moderate stiffness and strength reduction up to~400℃,followed by sharp deterioration beyond 500℃–600℃,with residual capacity at 700℃reduced to~20%–25%of the ambient value.Strain–damage analyses revealed the formation of a peripheral tensile strain band,which thickened and propagated inward with increasing temperature,governing crack initiation and cover spalling.Supplemental analyses highlighted that transverse reinforcement improved ductility and damage distribution at moderate temperatures(~300℃),but bond deterioration and steel softening beyond~600℃substantially diminished confinement effectiveness.The proposed CDP model accurately reproduced experimental stress–strain curves(R^(2)≈0.94–0.98 up to 600℃;≈0.90 at 700℃),with peak stress errors within 7%–10%and energy absorption captured within~12%.These findings confirm the robustness of the temperature-indexed CDP framework for simulating fire-damaged reinforced concrete and provide practical guidelines for post-fire assessment,spalling detection,and fire-resilient design of structural members.展开更多
Deep brain stimulation(DBS)is an established therapeutic intervention for people with Parkinson’s disease(PwPD)and is increasingly being utilized for other neurological disorders.Although effective in alleviating mot...Deep brain stimulation(DBS)is an established therapeutic intervention for people with Parkinson’s disease(PwPD)and is increasingly being utilized for other neurological disorders.Although effective in alleviating motor symptoms and reducing medication requirements,DBS has undergone minimal conceptual evolution and still relies on continuous high-frequency electrical stimulation.In Parkinson’s disease(PD),this persistent stimulation may cause adverse effects,including dysarthria,stimulation-induced dyskinesia,impulsivity,and mood alterations.Additionally,the continuous energy demand of current DBS systems accelerates battery depletion,necessitating more frequent battery charging or battery replacement surgeries,increasing risks,burden,and costs.Basic neuroscience research has long demonstrated that exogenous electrical stimulation can induce persistent changes to synaptic connections,known as long-term plasticity.展开更多
The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory ...The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.展开更多
Strength and plasticity of metallic structural materials are the fundamental indicators of the service reliability[1].However,as is well known,a general trade-offrelationship exists between strength and plasticity of ...Strength and plasticity of metallic structural materials are the fundamental indicators of the service reliability[1].However,as is well known,a general trade-offrelationship exists between strength and plasticity of metallic materials,making it difficult to improve both of them synchronously[2].At present,only few of the successful cases[3-8],achieved via nano-particles[7],heterogeneous microstructures[8],etc.are mostly limited to some specific materials or processes.展开更多
Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradie...Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradient to prevent the premature failure of fine grains in GS materials.In this work,by incorporating experimental data and the Hall-Petch relationship,we develop a size-dependent crystal plasticity model to investigate the deformation mechanisms for enhancing the strength and plasticity in polycrystalline high entropy alloys.The simulations of the GS model align well with the experimental results,exhibiting strong strain and stress gradients to improve the mechanical properties.Under the conditions of significant de-formation incompatibility,the strain gradient predominantly drives the enhancement of plasticity mechanisms.As the de-formation incompatibility decreases,the stress gradient begins to play a significant role in comparison with the strain gradient.This shift is attributed to the regular variations in dislocation density within different domains.As the grain size gradients and loads decrease,the dislocation density becomes more uniform across the domains,hindering the formation of strong domain boundaries.While this may impede the activation of strain gradients,it facilitates the activation of stress gradients as a supplementary measure.By designing multilayered GS structures to alter the distribution of dislocation density,we can control the activation levels of stress and strain gradients,thereby influencing the plasticity mechanisms and mechanical properties of the material.展开更多
Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grai...Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grain size),we tracked grain rotations for the first 1%of tensile strain,in 4400 time steps.We indexed 33 grains and quantified the magnitude and frequency of intermittent bursts of grain rotation.We interpret these events in terms of bursts of plastic deformation.The events are highly coordinated amongst nearby grains,and their frequency and magnitude,as well as the number of grains participating,peaked at around the onset of full plasticity.At this point,7 out of the 10 indexed grains with orientations favorable for twinning showed significant drops in diffracted intensity(a mean value of 8%),due to twin induced re-orientation.For other orientations,20 out of 23 grains displayed bursts attributable to lattice dislocation glide(interpreted in terms of basal and prismatic <α> slip).The mean value of the magnitude of these bursts is∼0.08°,implying accumulated shear strains of the order of 3×10^(-3).These bursts,in many cases,were due to the activation of more than a single slip/twin system within the grain,and co-ordination amongst neighboring grains also involved collaboration between slip and twinning events.展开更多
The authors regret for the missing of copyright attributions in the captions of Fig.1(d)and Fig.7 in the original publication.Please note the corrections do not affect the experimental results and conclusions.In the o...The authors regret for the missing of copyright attributions in the captions of Fig.1(d)and Fig.7 in the original publication.Please note the corrections do not affect the experimental results and conclusions.In the originally published article,Fig.1(d)and Fig.7 were adapted from previously published figures in the cited literature.展开更多
The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmiss...The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation mechanisms.These findings were discussed with the local strain measurements via digital image correlation.The results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of yielding.The small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier effect.The volume fraction of RA gradually decreased from 26.8%to 8.2%prior to fracture.In the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.展开更多
The visual cortex is an essential part of the brain for processing visual information.It exhibits structural and functional plasticity,which is crucial for adapting to complex visual environments.The quintessential ma...The visual cortex is an essential part of the brain for processing visual information.It exhibits structural and functional plasticity,which is crucial for adapting to complex visual environments.The quintessential manifestation of visual cortical plasticity is ocular dominance plasticity during the critical period,which involves numerous cellular and molecular events.While previous studies have emphasized the role of visual cortical neurons and their associated functional molecules in visual plasticity,recent findings have revealed that structural factors such as the extracellular matrix and glia are also involved.Investigating how these molecules interact to form a complex network that facilitates plasticity in the visual cortex is crucial to our understanding of the development of the visual system and the advancement of therapeutic strategies for visual disorders like amblyopia.展开更多
As the demand for advanced computational systems capable of handling large data volumes rises,nano-electronic devices,such as memristors,are being developed for efficient data processing,especially in reservoir comput...As the demand for advanced computational systems capable of handling large data volumes rises,nano-electronic devices,such as memristors,are being developed for efficient data processing,especially in reservoir computing(RC).RC enables the processing of temporal information with minimal training costs,making it a promising approach for neuromorphic computing.However,current memristor devices of-ten suffer from limitations in dynamic conductance and temporal behavior,which affects their perfor-mance in these applications.In this study,we present a multilayered indium-tin-oxide(ITO)/ZnO/indium-gallium-zinc oxide(IGZO)/ZnO/ITO memristor fabricated via radiofrequency sputtering to explore its fil-amentary and nonfilamentary resistive switching(RS)characteristics.High-resolution transmission elec-tron microscopy confirmed the polycrystalline structure of the ZnO/IGZO/ZnO active layer.Dual-switching modes were demonstrated by controlling the current compliance(I_(CC)).In the filamentary mode,the memristor exhibited a large memory window(10^(3)),low-operating voltages(±2 V),excellent cycle-to-cycle stability,and multilevel switching with controlled reset-stop voltages,making it suitable for high-density memory applications.Nonfilamentary switching demonstrated stable on/off ratios above 10,en-durance up to 102 cycles,and retention suited for short-term memory.Key synaptic behaviors,such as paired-pulse facilitation(PPF),post-tetanic potentiation(PTP),and spike-rate dependent plasticity(SRDP)were successfully emulated by modulating pulse amplitude,width,and interval.Experience-dependent plasticity(EDP)was also demonstrated,further replicating biological synaptic functions.These tempo-ral properties were utilized to develop a 4-bit reservoir computing system with 16 distinct conductance states,enabling efficient information encoding.For image recognition tasks,convolutional neural net-work(CNN)simulations achieved a high accuracy of 98.45%after 25 training epochs,outperforming the accuracy achieved following artificial neural network(ANN)simulations(87.79%).These findings demon-strate that the multilayered memristor exhibits high performance in neuromorphic systems,particularly for complex pattern recognition tasks,such as digit and letter classification.展开更多
OBJECTIVE:To investigate the effects of acupuncture combined with upper limb rehabilitation robot on neural remodeling and functional recovery in post-stroke patients.METHODS:There were 50 stroke patients were randoml...OBJECTIVE:To investigate the effects of acupuncture combined with upper limb rehabilitation robot on neural remodeling and functional recovery in post-stroke patients.METHODS:There were 50 stroke patients were randomly divided into an experimental group(acupuncture combined with upper limb rehabilitation robot assisted training)and a control group(upper limb rehabilitation robot assisted training).Various assessments were conducted to compare the effects of the two treatments on neural remodeling and functional recovery.Functional near-infrared spectroscopy technology was used to assess the effects of different treatments on neural plasticity and their impact on upper limb function and activities of daily living.RESULTS:The experimental group showed significantly higher concentrations of oxygenated hemoglobin and total hemoglobin in specific brain regions compared to the control group(P<0.05).Additionally,the experimental group had significantly lower concentrations of deoxygenated hemoglobin(P<0.05).After treatment,both groups showed improvements in various measures,but the experimental group had significantly greater improvements(P<0.05).CONCLUSION:Acupuncture combined with upper limb rehabilitation robot can effectively improve upper limb function and neural remodeling in stroke patients.This study supports the integration of Traditional Chinese and Western Medicine in improving limb dysfunction poststroke.展开更多
Refractory high-entropy alloys(RHEAs)are promising for high-temperature applications due to their ex-ceptional mechanical properties at high temperatures.However,limited studies on their high-temperature fatigue behav...Refractory high-entropy alloys(RHEAs)are promising for high-temperature applications due to their ex-ceptional mechanical properties at high temperatures.However,limited studies on their high-temperature fatigue behavior hinder further development.This study systematically investigates the low-cycle fatigue(LCF)behavior of HfNbTiZr RHEA at room temperature(25℃)and elevated temperatures(350,450,and 600℃)through a combination of experimental analyses and dislocation-based damage-coupled crystal plasticity finite element(CPFE)simulations,to unveil the effects of creep damage on LCF behavior at varying temperatures.The results indicate that the LCF life dramatically decreases at an increased tem-perature,shifting from transgranular fatigue damage at lower temperatures(25-350℃)to a dual damage mechanism involving both intergranular fatigue and creep damage at higher temperatures(450-600℃).At 600℃,creep damage notably contributes to the accumulation of geometrically necessary dislocations(GNDs),crack initiation,and propagation at grain boundaries,and thus accelerates LCF failure.Compara-tive CPFE simulations reveal that creep damage significantly contributes to cyclic softening and reduction in elastic modulus,which also amplifies the strain localization under the LCF loading.The contribution of creep damage to the total stored energy density(SED)representing the overall damage increases with temperatures,accounting for 11%at 600℃.Additionally,CPFE simulations indicate that the creep dam-age notably influences the magnitude of GND density localized at grain boundaries.This study provides critical insights into the fatigue damage mechanisms of RHEAs,offering valuable guidance for their ap-plication in high temperatures.展开更多
基金financially supported by King Abdulaziz University,Deanship of Scientific Research(DSR)。
文摘Neuronal plasticity,the brain's ability to adapt structurally and functionally,is essential for learning,memory,and recovery from injuries.In neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease,this plasticity is disrupted,leading to cognitive and motor deficits.This review explores the mechanisms of neuronal plasticity and its effect on Alzheimer's disease and Parkinson's disease.Alzheimer's disease features amyloid-beta plaques and tau tangles that impair synaptic function,while Parkinson's disease involves the loss of dopaminergic neurons affecting motor control.Enhancing neuronal plasticity offers therapeutic potential for these diseases.A systematic literature review was conducted using databases such as PubMed,Scopus,and Google Scholar,focusing on studies of neuronal plasticity in Alzheimer's disease and Parkinson's disease.Data synthesis identified key themes such as synaptic mechanisms,neurogenesis,and therapeutic strategies,linking molecular insights to clinical applications.Results highlight that targeting synaptic plasticity mechanisms,such as long-term potentiation and long-term depression,shows promise.Neurotrophic factors,advanced imaging techniques,and molecular tools(e.g.,clustered regularly interspaced short palindromic repeats and optogenetics)are crucial in understanding and enhancing plasticity.Current therapies,including dopamine replacement,deep brain stimulation,and lifestyle interventions,demonstrate the potential to alleviate symptoms and improve outcomes.In conclusion,enhancing neuronal plasticity through targeted therapies holds significant promise for treating neurodegenerative diseases.Future research should integrate multidisciplinary approaches to fully harness the therapeutic potential of neuronal plasticity in Alzheimer's disease and Parkinson's disease.
基金supported by Japan Society forthe Promotion of Science(JSPS)Grants-in-Aidfor Scientific Research(KAKENHI)(20H05894,20H05903,21K15136,22K21351,23H02518A,23H02663,and 23K18147 to SS),JST-CREST(JPMJCR24T4 to SS),the World PremierInternational Research Center Initiative(WPI)fromthe Ministry of Education,Culture,Sports,Scienceand Technology(MEXT)to SS(WPI-IIIS),the TopRunners in Strategy of Transborder AdvancedResearches(TRiSTAR)by the MEXT to SSJapanAgency for Medical Research and Development(AMED)(JP21zf0127005 to SS),Cell ScienceResearch Foundation Grant to YI,38th Brain ScienceFoundation Research Grant to YI,Research Granton Biogenic Amines and Neurological Diseases(Sumitomo pharma)to YI.
文摘Sleep is a fundamental biological process essential for maintaining brain function,cognitive performance,and overall health.Despite over a century of research,the mechanisms underlying sleep homeostasis-the process by which the need for sleep accumulates during wakefulness and dissipates during sleep-remain incompletely understood.This article explores the latest advancements in sleep research,focusing on the role of synaptic plasticity in sleep homeostasis,as illuminated by Sawada et al.(2024).
文摘Nonlinear static procedures are widely adopted in structural engineering practice for seismic performance assessment due to their simplicity and computational efficiency.However,their reliability depends heavily on how the nonlinear behaviour of structural components is represented.The recent earthquakes in Albania(2019)and Türkiye(2023)have underscored the need for accurate assessment techniques,particularly for older reinforced concrete buildings with poor detailing.This study quantifies the discrepancies between default and user-defined component modelling in pushover analysis of pre-modern reinforced concrete structures,analysing two representative low-and mid-rise reinforced concrete frame buildings.The lumped plasticity approach incorporates moment-rotation relationships derived from actual member properties and reinforcement configurations,while the distributed plasticity approach uses software-generated default properties based on modern codes.Results show that the distributed plasticity models systematically overestimate both the strength and the deformation capacity by up to 35%compared to lumped plasticity models,especially in buildings with poor detailing and low concrete strength.These findings demonstrate that default software procedures,widely used in practice but not validated for pre-modern structures,produce dangerously unconservative seismic performance estimates.The study provides quantitative evidence of the critical need for tailored modelling strategies that reflect the actual conditions of the existing building stock.
基金supported by Progetto Trapezio,Compagnia di San Paolo(67935-2021.2174),to LBFondazione CRT(Cassa di Risparmio di Torino,RF=2022.0618),to LBPRIN2022(grant 2022LB4X3N),to LB。
文摘The capacity of the central nervous system for structural plasticity and regeneration is commonly believed to show a decreasing progression from“small and simple”brains to the larger,more complex brains of mammals.However,recent findings revealed that some forms of neural plasticity can show a reverse trend.Although plasticity is a well-preserved,transversal feature across the animal world,a variety of cell populations and mechanisms seem to have evolved to enable structural modifications to take place in widely different brains,likely as adaptations to selective pressures.Increasing evidence now indicates that a trade-off has occurred between regenerative(mostly stem cell–driven)plasticity and developmental(mostly juvenile)remodeling,with the latter primarily aimed not at brain repair but rather at“sculpting”the neural circuits based on experience.In particular,an evolutionary trade-off has occurred between neurogenic processes intended to support the possibility of recruiting new neurons throughout life and the different ways of obtaining new neurons,and between the different brain locations in which plasticity occurs.This review first briefly surveys the different types of plasticity and the complexity of their possible outcomes and then focuses on recent findings showing that the mammalian brain has a stem cell–independent integration of new neurons into pre-existing(mature)neural circuits.This process is still largely unknown but involves neuronal cells that have been blocked in arrested maturation since their embryonic origin(also termed“immature”or“dormant”neurons).These cells can then restart maturation throughout the animal's lifespan to become functional neurons in brain regions,such as the cerebral cortex and amygdala,that are relevant to high-order cognition and emotions.Unlike stem cell–driven postnatal/adult neurogenesis,which significantly decreases from small-brained,short-living species to large-brained ones,immature neurons are particularly abundant in large-brained,long-living mammals,including humans.The immature neural cell populations hosted in these complex brains are an interesting example of an“enlarged road”in the phylogenetic trend of plastic potential decreases commonly observed in the animal world.The topic of dormant neurons that covary with brain size and gyrencephaly represents a prospective turning point in the field of neuroplasticity,with important translational outcomes.These cells can represent a reservoir of undifferentiated neurons,potentially granting plasticity within the high-order circuits subserving the most sophisticated cognitive skills that are important in the growing brains of young,healthy individuals and are frequently affected by debilitating neurodevelopmental and degenerative disorders.
文摘Regenerative capacity of the central nervous system(CNS)is unevenly distributed among vertebrates.While most mammalian species including humans elicit limited repair following CNS injury or disease,highly regenerative vertebrates including urodele amphibians and teleost fish spontaneously reverse CNS damage.Teletost zebrafish(danio rerio)are tropical freshwater fish that proved to be an excellent vertebrate model of successful CNS regeneration.Differential neuronal,glial,and immune injury responses underlie disparate injury outcomes between highly regenerative zebrafish and poorly regenerative mammals.This article describes complications associated with neuronal repair following spinal cord injury(SCI)in poorly regenerative mammals and highlights intersecting modes of plasticity and regeneration in highly regenerative zebrafish(Figures 1 and 2).Comparative approaches evaluating immunoglial SCI responses were recently reviewed elsewhere(Reyes and Mokalled,2024).
基金supported by the National Natural Science Foundation of China(No.52371004,52201144,52071040,U20A20230).
文摘Bending is a crucial operation in the sheet forming of Mg alloys for automotive and aerospace applications.In this work,three kinds of sheets from an AZ31 rolled plate,sheared at 0°(S0),45°(S45),and 90°(S90)to the rolling direction,were subjected to three-point bending tests.In-situ digital image correlation(DIC)system was employed to capture the strain fields.Electron backscatter diffraction(EBSD)was used to examine the through-thickness microstructures.A crystal plasticity finite element method(CPFEM)incorporating twinning and slip mechanisms was developed to simulate the bending deformation.The texture effect on the neutral layer shift and twinning behaviors was systematically investigated in terms of both experiments and simulations.The results show that CPFEM effectively simulated the texturedependent shifting behaviors of neutral layer and the associated twinning behaviors.Particularly,the spatial distributions of neutral layer across the entire bent plates were captured by both DIC and CPFEM.Additionally,some unusual twinning behaviors were analyzed in depth,such as the{10-12}-{10-12}secondary twins in S90,localized twin bands in S0,and the twin traces difference in S45.These findings reveal a close relationship between the neutral layer shift and twinning activity induced by the initial texture and strain levels.This work provides valuable insights into the bending deformation mechanisms of Mg alloys and has important implications for improving their formability and controlling springback.
基金supported by the National Natural Science Foundation of China(Nos.82430116 and 82574622)the Special Fund of Central Committee High Level Chinese Medicine Hospital(Nos.DZMG-LJRC-0014,DZMG-ZJXY-23013)+1 种基金Chinese Medicine Inheritance and Innovation“Thousand Million”Talents Project(Qihuang Project 2021)Qihuang Scholarsthe Medical and Health Industry Development Project of Tongzhou District(2023).
文摘Chronic heart failure(CHF)impairs cognitive function.Xijiaqi Formula(XJQ),a traditional Chinese medicine(TCM)used clinically to treat CHF,demonstrates potential for improving cognition in CHF patients.However,its precise mechanism in treating post-CHF cognitive dysfunction remains unclear.This study systematically investigates XJQ’s effects on post-CHF cognitive dysfunction and the underlying mechanisms.The components of XJQ were identified through liquid chromatography-mass spectrometry.CHF was induced in rats via ligation of the left anterior descending coronary artery,followed by six weeks of XJQ treatment.Cardiac function was evaluated through echocardiography and hemodynamic parameters,while cognitive function was assessed using Morris water maze(MWM)and open field tests(OFT).XJQ treatment enhanced both cardiac and cognitive functions in CHF rats.Network pharmacology identified 12 core active components of XJQ and indicated its effect on cognitive dysfunction involved regulating synapses,inflammation,and phosphodiesterase 4(PDE4)-dependent cyclic adenosine monophosphate(cAMP)signaling.XJQ inhibited microglial and astrocyte activation,decreased proinflammatory cytokines,and mitigated neuronal damage.Notably,XJQ promoted synaptic repair and dendritic growth by downregulating PDE4 and upregulating cAMP,protein kinase A(PKA),cAMP-response element binding protein(CREB),brain-derived neurotrophic factor(BDNF),PSD95,and synapsin I levels.Molecular docking and Bio-layer interferometry assays confirmed direct binding of quercetin,kaempferol,isorhamnetin,and darutoside to PDE4.In conclusion,XJQ alleviates neuroinflammation and enhances synaptic plasticity to improve cognitive dysfunction in CHF rats via the PDE4/cAMP/PKA/CREB signaling pathway.These findings provide valuable insight into the heart-brain axis.
基金support from the National Natural Science Foundation of China(Grant Nos.42277161 and 42230709).
文摘In rock engineering,natural cracks in rock masses subjected to external loads tend to initiate and propagate,leading to potential safety hazards.To investigate the effect of cracking behavior on the mechanical properties of rocks,the cracking processes of pre-cracked rocks have been extensively studied using numerical modeling methods.The peridynamics(PD)exhibits advantages over other numerical methods due to the absence of the requirements for remeshing and external crack growth criterion.However,for modeling pre-cracked rock cracking processes under impact,current PD implementations lack generally applicable rock constitutive models and impact contact models,which leads to difficulties in determining rock material parameters and efficiently calculating impact loads.This paper proposes a non-ordinary state-based peridynamics(NOSBPD)modeling method integrating the Drucker-Prager(DP)plasticity model and an efficient contact model to address the above problems.In the proposed method,the Drucker-Prager plasticity model is integrated into the NOSBPD,thereby equipping NOSBPD with the capability to accurately characterize the nonlinear stress-strain relationship inherent in rocks.An efficient contact model between particles and meshes is designed to calculate the impact loads,which is essentially a coupling method of PD with the finite element method(FEM).The effectiveness of the proposed NOSBPD modeling method is verified by comparison with other numerical methods and experiments.Experimental results indicate that the proposed method can effectively and accurately predict the 3D cracking processes of pre-cracked cracks under impact loading,and the maximum principal stress is the key driver behind wing crack formation in pre-cracked rocks.
文摘This study investigates the thermo–mechanical behavior of C40 concrete and reinforced concrete subjected to elevated temperatures up to 700℃by integrating experimental testing and advanced numerical modeling.A temperature-indexed Concrete Damage Plasticity(CDP)framework incorporating bond–slip effects was developed in Abaqus to capture both global stress–strain responses and localized damage evolution.Uniaxial compression tests on thermally exposed cylinders provided residual strength data and failure observations for model calibration and validation.Results demonstrated a distinct two-stage degradation regime:moderate stiffness and strength reduction up to~400℃,followed by sharp deterioration beyond 500℃–600℃,with residual capacity at 700℃reduced to~20%–25%of the ambient value.Strain–damage analyses revealed the formation of a peripheral tensile strain band,which thickened and propagated inward with increasing temperature,governing crack initiation and cover spalling.Supplemental analyses highlighted that transverse reinforcement improved ductility and damage distribution at moderate temperatures(~300℃),but bond deterioration and steel softening beyond~600℃substantially diminished confinement effectiveness.The proposed CDP model accurately reproduced experimental stress–strain curves(R^(2)≈0.94–0.98 up to 600℃;≈0.90 at 700℃),with peak stress errors within 7%–10%and energy absorption captured within~12%.These findings confirm the robustness of the temperature-indexed CDP framework for simulating fire-damaged reinforced concrete and provide practical guidelines for post-fire assessment,spalling detection,and fire-resilient design of structural members.
文摘Deep brain stimulation(DBS)is an established therapeutic intervention for people with Parkinson’s disease(PwPD)and is increasingly being utilized for other neurological disorders.Although effective in alleviating motor symptoms and reducing medication requirements,DBS has undergone minimal conceptual evolution and still relies on continuous high-frequency electrical stimulation.In Parkinson’s disease(PD),this persistent stimulation may cause adverse effects,including dysarthria,stimulation-induced dyskinesia,impulsivity,and mood alterations.Additionally,the continuous energy demand of current DBS systems accelerates battery depletion,necessitating more frequent battery charging or battery replacement surgeries,increasing risks,burden,and costs.Basic neuroscience research has long demonstrated that exogenous electrical stimulation can induce persistent changes to synaptic connections,known as long-term plasticity.
基金supported by the Deutsche Forschungsgemeinschaft(DFG),TRR274(Project ID 408885537,Sy Nergy,EXC 2145/ID 390857198,to FMB)。
文摘The remodeling of axonal connections following injury is an important feature driving functional recovery.The reticulospinal tract is an interesting descending motor tract that contains both excitatory and inhibitory fibers.While the reticulospinal tract has been shown to be particularly prone to axonal growth and plasticity following injuries of the spinal cord,the differential capacities of excitatory and inhibitory fibers for plasticity remain unclear.As adaptive axonal plasticity involves a sophisticated interplay between excitatory and inhibitory input,we investigated in this study the plastic potential of glutamatergic(vGlut2)and GABAergic(vGat)fibers originating from the gigantocellular nucleus and the lateral paragigantocellular nucleus,two nuclei important for locomotor function.Using a combination of viral tracing,chemogenetic silencing,and AI-based kinematic analysis,we investigated plasticity and its impact on functional recovery within the first 3 weeks following injury,a period prone to neuronal remodeling.We demonstrate that,in this time frame,while vGlut2-positive fibers within the gigantocellular and lateral paragigantocellular nuclei rewire significantly following cervical spinal cord injury,vGat-positive fibers are rather unresponsive to injury.We also show that the acute silencing of excitatory axonal fibers which rewire in response to lesions of the spinal cord triggers a worsening of the functional recovery.Using kinematic analysis,we also pinpoint the locomotion features associated with the gigantocellular nucleus or lateral paragigantocellular nucleus during functional recovery.Overall,our study increases the understanding of the role of the gigantocellular and lateral paragigantocellular nuclei during functional recovery following spinal cord injury.
基金financially supported by the National Natural Science Foundation of China(NSFC)(Nos.52371084,52301177,52322105,52130002,and 52321001)the Youth Innovation Promotion Association CAS(No.2021192)+1 种基金the IMR Innovation Fund(No.2023-ZD01)the Fund of Science and Technology on Surface Physics and Chemistry Laboratory(No.XKFZ202303).
文摘Strength and plasticity of metallic structural materials are the fundamental indicators of the service reliability[1].However,as is well known,a general trade-offrelationship exists between strength and plasticity of metallic materials,making it difficult to improve both of them synchronously[2].At present,only few of the successful cases[3-8],achieved via nano-particles[7],heterogeneous microstructures[8],etc.are mostly limited to some specific materials or processes.
基金supported by the National Natural Science Foundation of China(Grant Nos.12372069,12172123,and 12072109)the Natural Science Foundation of Hunan Province(Grant No.2022JJ20001)the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX20220378).
文摘Gradient structures(GS)play a crucial role in achieving a balance between strength and plasticity in metals and alloys.However,there is still a lack of understanding of the mechanisms that maintain a plasticity gradient to prevent the premature failure of fine grains in GS materials.In this work,by incorporating experimental data and the Hall-Petch relationship,we develop a size-dependent crystal plasticity model to investigate the deformation mechanisms for enhancing the strength and plasticity in polycrystalline high entropy alloys.The simulations of the GS model align well with the experimental results,exhibiting strong strain and stress gradients to improve the mechanical properties.Under the conditions of significant de-formation incompatibility,the strain gradient predominantly drives the enhancement of plasticity mechanisms.As the de-formation incompatibility decreases,the stress gradient begins to play a significant role in comparison with the strain gradient.This shift is attributed to the regular variations in dislocation density within different domains.As the grain size gradients and loads decrease,the dislocation density becomes more uniform across the domains,hindering the formation of strong domain boundaries.While this may impede the activation of strain gradients,it facilitates the activation of stress gradients as a supplementary measure.By designing multilayered GS structures to alter the distribution of dislocation density,we can control the activation levels of stress and strain gradients,thereby influencing the plasticity mechanisms and mechanical properties of the material.
基金the Australian Research Council through the Discovery Grant DP200100727 and Laureate Fellowship FL210100147。
文摘Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grain size),we tracked grain rotations for the first 1%of tensile strain,in 4400 time steps.We indexed 33 grains and quantified the magnitude and frequency of intermittent bursts of grain rotation.We interpret these events in terms of bursts of plastic deformation.The events are highly coordinated amongst nearby grains,and their frequency and magnitude,as well as the number of grains participating,peaked at around the onset of full plasticity.At this point,7 out of the 10 indexed grains with orientations favorable for twinning showed significant drops in diffracted intensity(a mean value of 8%),due to twin induced re-orientation.For other orientations,20 out of 23 grains displayed bursts attributable to lattice dislocation glide(interpreted in terms of basal and prismatic <α> slip).The mean value of the magnitude of these bursts is∼0.08°,implying accumulated shear strains of the order of 3×10^(-3).These bursts,in many cases,were due to the activation of more than a single slip/twin system within the grain,and co-ordination amongst neighboring grains also involved collaboration between slip and twinning events.
文摘The authors regret for the missing of copyright attributions in the captions of Fig.1(d)and Fig.7 in the original publication.Please note the corrections do not affect the experimental results and conclusions.In the originally published article,Fig.1(d)and Fig.7 were adapted from previously published figures in the cited literature.
基金supported by the National Key R&D Program of China(No.2017YFB0304402)。
文摘The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigated during uniaxial tensile testing.In-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation mechanisms.These findings were discussed with the local strain measurements via digital image correlation.The results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sized retained austenite(RA),which led to localized stress concentrations and strain hardening and further retardation of yielding.The small-sized RA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier effect.The volume fraction of RA gradually decreased from 26.8%to 8.2%prior to fracture.In the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.
基金supported by the National Natural Science Foundation of China(81770956,81371049,32471055 and 82171090)Project of Tianjin 131 Innovative Talent Team(201936)+4 种基金the Science and Technology Planning Project of Tianjin(21JCYBJC00780)the Science and Technology Fund for Health of Tianjin(TJWJ2023ZD008)Shanghai Municipal Science and Technology Major Project(2018SHZDZX01)ZJLab,Shanghai Center for Brain Science and Brain-Inspired Technology,the Lingang Laboratory(LG-QS-202203-12)Tianjin Key Medical Discipline(Specialty)Construction Project(TJYXZDXK‑016A).
文摘The visual cortex is an essential part of the brain for processing visual information.It exhibits structural and functional plasticity,which is crucial for adapting to complex visual environments.The quintessential manifestation of visual cortical plasticity is ocular dominance plasticity during the critical period,which involves numerous cellular and molecular events.While previous studies have emphasized the role of visual cortical neurons and their associated functional molecules in visual plasticity,recent findings have revealed that structural factors such as the extracellular matrix and glia are also involved.Investigating how these molecules interact to form a complex network that facilitates plasticity in the visual cortex is crucial to our understanding of the development of the visual system and the advancement of therapeutic strategies for visual disorders like amblyopia.
基金supported by the National R&D Pro-gram through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT(Nos.RS-2024-00356939 and RS-2024-00405691).
文摘As the demand for advanced computational systems capable of handling large data volumes rises,nano-electronic devices,such as memristors,are being developed for efficient data processing,especially in reservoir computing(RC).RC enables the processing of temporal information with minimal training costs,making it a promising approach for neuromorphic computing.However,current memristor devices of-ten suffer from limitations in dynamic conductance and temporal behavior,which affects their perfor-mance in these applications.In this study,we present a multilayered indium-tin-oxide(ITO)/ZnO/indium-gallium-zinc oxide(IGZO)/ZnO/ITO memristor fabricated via radiofrequency sputtering to explore its fil-amentary and nonfilamentary resistive switching(RS)characteristics.High-resolution transmission elec-tron microscopy confirmed the polycrystalline structure of the ZnO/IGZO/ZnO active layer.Dual-switching modes were demonstrated by controlling the current compliance(I_(CC)).In the filamentary mode,the memristor exhibited a large memory window(10^(3)),low-operating voltages(±2 V),excellent cycle-to-cycle stability,and multilevel switching with controlled reset-stop voltages,making it suitable for high-density memory applications.Nonfilamentary switching demonstrated stable on/off ratios above 10,en-durance up to 102 cycles,and retention suited for short-term memory.Key synaptic behaviors,such as paired-pulse facilitation(PPF),post-tetanic potentiation(PTP),and spike-rate dependent plasticity(SRDP)were successfully emulated by modulating pulse amplitude,width,and interval.Experience-dependent plasticity(EDP)was also demonstrated,further replicating biological synaptic functions.These tempo-ral properties were utilized to develop a 4-bit reservoir computing system with 16 distinct conductance states,enabling efficient information encoding.For image recognition tasks,convolutional neural net-work(CNN)simulations achieved a high accuracy of 98.45%after 25 training epochs,outperforming the accuracy achieved following artificial neural network(ANN)simulations(87.79%).These findings demon-strate that the multilayered memristor exhibits high performance in neuromorphic systems,particularly for complex pattern recognition tasks,such as digit and letter classification.
基金Supported by Zhejiang Province Traditional Chinese Medicine Science and Technology Project(2024ZL769):Effect of Xingshen Kaiqiao Acupuncture Method combined with Upper Limb Robot-assisted Training on Upper Limb Function and Neuroplasticity Mechanism of Hemiplegia after Stroke based on Functional Near-Infrared Spectroscopy Technology。
文摘OBJECTIVE:To investigate the effects of acupuncture combined with upper limb rehabilitation robot on neural remodeling and functional recovery in post-stroke patients.METHODS:There were 50 stroke patients were randomly divided into an experimental group(acupuncture combined with upper limb rehabilitation robot assisted training)and a control group(upper limb rehabilitation robot assisted training).Various assessments were conducted to compare the effects of the two treatments on neural remodeling and functional recovery.Functional near-infrared spectroscopy technology was used to assess the effects of different treatments on neural plasticity and their impact on upper limb function and activities of daily living.RESULTS:The experimental group showed significantly higher concentrations of oxygenated hemoglobin and total hemoglobin in specific brain regions compared to the control group(P<0.05).Additionally,the experimental group had significantly lower concentrations of deoxygenated hemoglobin(P<0.05).After treatment,both groups showed improvements in various measures,but the experimental group had significantly greater improvements(P<0.05).CONCLUSION:Acupuncture combined with upper limb rehabilitation robot can effectively improve upper limb function and neural remodeling in stroke patients.This study supports the integration of Traditional Chinese and Western Medicine in improving limb dysfunction poststroke.
基金National Science Foundation of China(Nos.52401212 and52401214)the National Science Foundation of Jiangsu Province(No.BK20241020)+1 种基金the Avi-ation Foundation(No.2023Z0530S6004)the Jiangsu Province University Collaborative Innovation Centre(High-Tech Ships)Pro-gram(No.XTCX202401).
文摘Refractory high-entropy alloys(RHEAs)are promising for high-temperature applications due to their ex-ceptional mechanical properties at high temperatures.However,limited studies on their high-temperature fatigue behavior hinder further development.This study systematically investigates the low-cycle fatigue(LCF)behavior of HfNbTiZr RHEA at room temperature(25℃)and elevated temperatures(350,450,and 600℃)through a combination of experimental analyses and dislocation-based damage-coupled crystal plasticity finite element(CPFE)simulations,to unveil the effects of creep damage on LCF behavior at varying temperatures.The results indicate that the LCF life dramatically decreases at an increased tem-perature,shifting from transgranular fatigue damage at lower temperatures(25-350℃)to a dual damage mechanism involving both intergranular fatigue and creep damage at higher temperatures(450-600℃).At 600℃,creep damage notably contributes to the accumulation of geometrically necessary dislocations(GNDs),crack initiation,and propagation at grain boundaries,and thus accelerates LCF failure.Compara-tive CPFE simulations reveal that creep damage significantly contributes to cyclic softening and reduction in elastic modulus,which also amplifies the strain localization under the LCF loading.The contribution of creep damage to the total stored energy density(SED)representing the overall damage increases with temperatures,accounting for 11%at 600℃.Additionally,CPFE simulations indicate that the creep dam-age notably influences the magnitude of GND density localized at grain boundaries.This study provides critical insights into the fatigue damage mechanisms of RHEAs,offering valuable guidance for their ap-plication in high temperatures.
