Pyramidal dislocations are important for ductility enhancement of magnesium alloys.In this work,molecular dynamics simulations were employed to study the gliding behavior of pyramidal(c+a)dislocations under c-axis com...Pyramidal dislocations are important for ductility enhancement of magnesium alloys.In this work,molecular dynamics simulations were employed to study the gliding behavior of pyramidal(c+a)dislocations under c-axis compressive loading and tensile loading.The Peierls stress of Py-Ⅰ dislocation shows strong tension-compression asymmetry.However,no tension-compression asymmetry is seen on the Py-Ⅱ dislocation and basal dislocation.The tension-compression asymmetry origins from the asymmetry of partial dislocations of Py-Ⅰ dislocation,which leads to the dislocation core contracted under c-axis compressive loading and expanded under tensile loading.By analyzing the forces acting on the partial dislocations,we defined a neutral direction,which deviates from the full dislocation Burgers vector by 70.3°.The neutral direction is dependent on the ratio of lattice stresses of partial dislocations.If the shear stress is applied along the neutral direction,tension-compression asymmetry is eliminated and the dislocation core is un-contracted/un-expanded.The neutral direction of symmetrical dislocations(Py-Ⅱ dislocation and basal dislocation)is just the full dislocation Burgers vector.The tension-compression asymmetry and dislocation core contraction/expansion have an important influence on the dislocation behaviors,such as cross-slip,decomposition,basaltransition and mobility,which can be used to explain the mechanical behaviors of Mg single-crystals compressed along c-axis.展开更多
As the largest desert in China,the Taklimakan Desert features unique mobility and alternating mega-dune and inter-dune landscapes with rich dune types.Most areas of the sand sea were explored in the early 20th century...As the largest desert in China,the Taklimakan Desert features unique mobility and alternating mega-dune and inter-dune landscapes with rich dune types.Most areas of the sand sea were explored in the early 20th century.However,the eastern Taklimakan Desert characterized by extremely tall dunes,had received little attention until 2022 owing to transportation inconveniences.This study examined the alternating mega-dune and inter-dune landscapes in the eastern Taklimakan Desert,through spatial analysis and field surveys.Results demonstrate that the tallest mega-dunes are distributed primarily to the east of the central desert,with the occurrence of approximately 240 mega-dunes exceeding 150 m in height.The height-spacing relationship of mega-dunes with different orders exhibits a weak correlation,suggesting that the dune formation and evolution are more complex than previously documented;this could be attributed to the factors other than solely the wind regime.Additionally,from the field survey,we found that sand availability is the dominant factor for constraining the sustained growth of mega-dunes.A pattern coarsening may be responsible for the development of the dune fields in the eastern Taklimakan Desert,thus yielding constraints on the development of mega-dunes,and other dune fields on Earth as well.展开更多
Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temper...Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temperatures.This study investigates the DRX mechanisms in AZWX3100 magnesium alloy under plane strain compression at 200℃.Microstructural analysis revealed necklace-type DRX accompanied by evidence of local grain boundary bulging.Additionally,ribbons of recrystallized grains were observed withinfine deformation bands,aligned with theoretical pyramidal I and II slip traces derived from the matrix.The distribution of local misorientation within the deformed microstructure demonstrated a clear association between deformation bands and localized strain.Dislocation analysis of lamellar specimens extracted from two pyramidal slip bands revealed<c+a>dislocations,indicating a connection between<c+a>slip activation and the formation of deformation bands.Crystal plasticity simulations suggest that the orientation of deformation bands is responsible for the unique recrystallization texture of the DRX grains within these bands.The texture characteristics imply a progressive,glide-induced DRX mechanism.A fundamental understanding of the role of deformation bands in texture modification can facilitate future alloy and process design.展开更多
Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a com...Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a computational investigation of a novel Multi-Focal Pyramidal Array(MFPA)-based CPV system designed to overcome this limitation.The MFPA architecture employs a geometrically optimized pyramidal concentrator to distribute concen-trated sunlight onto strategically placed,low-cost monocrystalline silicon cells,enabling high efficiency energy capture while passively managing thermal loads.Coupled optical thermal electrical simulations in COMSOL Multiphysics demonstrate a geometric concentration ratio of 120×,with system temperatures maintained below 110℃ under standard 1000 W/m2 Direct Normal Irradiance(DNI).Ray tracing confirms 95%optical efficiency and a concentrated light spot radius of 2.48 mm.Compared with conventional CPV designs,the MFPA improves power-per-cost by 25%and reduces tracking requirements by 50%owing to its wide±15°acceptance angle.These results highlight the MFPA’s potential as a scalable,low-cost,and energy-efficient pathway for expanding solar power generation.展开更多
Dear Editor,The importance of the medial entorhinal cortex(MEC)for memory and spatial navigation has been shown repeatedly in many species,including mice and humans[1,2].It is,therefore,not surprising that the connect...Dear Editor,The importance of the medial entorhinal cortex(MEC)for memory and spatial navigation has been shown repeatedly in many species,including mice and humans[1,2].It is,therefore,not surprising that the connectivity of this structure has been studied extensively over the past century,mainly using a range of anterograde and retrograde anatomical tracers[3].展开更多
Accurate detection of smoke and fire sources is critical for early fire warning and environmental monitoring.However,conventional detection approaches are highly susceptible to noise,illumination variations,and comple...Accurate detection of smoke and fire sources is critical for early fire warning and environmental monitoring.However,conventional detection approaches are highly susceptible to noise,illumination variations,and complex environmental conditions,which often reduce detection accuracy and real-time performance.To address these limitations,we propose Lightweight and Precise YOLO(LP-YOLO),a high-precision detection framework that integrates a self-attention mechanism with a feature pyramid,built upon YOLOv8.First,to overcome the restricted receptive field and parameter redundancy of conventional Convolutional Neural Networks(CNNs),we design an enhanced backbone based on Wavelet Convolutions(WTConv),which expands the receptive field through multifrequency convolutional processing.Second,a Bidirectional Feature Pyramid Network(BiFPN)is employed to achieve bidirectional feature fusion,enhancing the representation of smoke features across scales.Third,to mitigate the challenge of ambiguous object boundaries,we introduce the Frequency-aware Feature Fusion(FreqFusion)module,in which the Adaptive Low-Pass Filter(ALPF)reduces intra-class inconsistencies,the offset generator refines boundary localization,and the Adaptive High-Pass Filter(AHPF)recovers high-frequency details lost during down-sampling.Experimental evaluations demonstrate that LP-YOLO significantly outperforms the baseline YOLOv8,achieving an improvement of 9.3%in mAP@50 and 9.2%in F1-score.Moreover,the model is 56.6%and 32.4%smaller than YOLOv7-tiny and EfficientDet,respectively,while maintaining real-time inference speed at 238 frames per second(FPS).Validation on multiple benchmark datasets,including D-Fire,FIRESENSE,and BoWFire,further confirms its robustness and generalization ability,with detection accuracy consistently exceeding 82%.These results highlight the potential of LP-YOLO as a practical solution with high accuracy,robustness,and real-time performance for smoke and fire source detection.展开更多
The mechanical performance of an all-composite pyramidal lattice truss core sandwich structure was investigated both theoretically and experimentally.Sandwich structures were fabricated with a hot compression molding ...The mechanical performance of an all-composite pyramidal lattice truss core sandwich structure was investigated both theoretically and experimentally.Sandwich structures were fabricated with a hot compression molding method using carbon fiber reinforced composite T700/3234.The out-of-plane compression and shear tests were conducted.Experimental results showed that the all-composite pyramidal lattice truss core sandwich structures were more weight efficient than other metallic lattice truss core sandwich structures.Failure modes revealed that node rupture dominated the mechanical behavior of sandwich structures.展开更多
The equation of motion of sandwich beam with pyramidal lattice core in the supersonic flow considering geometric nonlinearity is formulated using Hamilton＇s principle. The piston theory is used to evaluate aerodynami...The equation of motion of sandwich beam with pyramidal lattice core in the supersonic flow considering geometric nonlinearity is formulated using Hamilton＇s principle. The piston theory is used to evaluate aerodynamic pressure. The structural aeroelastic properties are analyzed using frequency- and time-domain methods, and some interesting phenomena are observed. It is noted that the flutter of sandwich beam occurs under the coupling effect of low order modes. The critical flutter aerodynamic pressure of the sandwich beam is higher than that of the isotropic beam with the same weight, length and width. The influence of inclination angle of core truss on flutter characteristic is analyzed.展开更多
The complex interactions in desert ecosystems between functional types and environmental conditions could be reflected by plant water use patterns. However, the mechanisms underlying the water use patterns as well as ...The complex interactions in desert ecosystems between functional types and environmental conditions could be reflected by plant water use patterns. However, the mechanisms underlying the water use patterns as well as the water sources of Tamarix laxa in the mega-dunes of the Badain Jaran Desert, China, remain unclear. This study investigated the water sources and water use patterns of T. laxa using the stable oxygen isotope method. The δ18O values of xylem water, soil water in different layers(0–200 cm), rainwater, snow water, lake water, atmospheric water vapor, condensate water, and groundwater were measured. The sources of water used by T. laxa were determined using the IsoSource model. The results indicate that T. laxa mainly relies on soil water. At the beginning of the growing season(in May), the species is primarily dependent on water from the middle soil layer(60–120 cm) and deep soil layer(120–200 cm). However, it mainly absorbs water from the shallow soil layer(0–60 cm) as the rainy season commences. In September, water use of T. laxa reverts to the deep soil layer(120–200 cm). The water use patterns of T. laxa are closely linked with heavy precipitation events and soil water content. These findings reveal the drought resistance mechanisms of T. laxa and are of significance for screening species for ecological restoration.展开更多
The aberrant pyramidal tract refers to the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 63-year-old male patient presented with severe paralysis of the left extremities du...The aberrant pyramidal tract refers to the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 63-year-old male patient presented with severe paralysis of the left extremities due to a right corona radiata infarct. He was able to extend the affected fingers against resistance at 2 months after stroke onset. At 6 months after stroke onset, he was able to perform some fine motor activities, as well as to walk with a nearly normal gait. Functional MRI, which was performed at 6 months after onset, showed that the contralateral primary sensorimotor cortex was activated during affected （left） hand movements. Diffusion tensor tractography results showed that at 2 weeks after stroke onset, pyramidal tracts of the affected hemisphere originated from the primary motor cortex and descended along the known pathway of the pyramidal tract with an aberrant pyramidal tract, which was bypassed through the medial lemniscus from the midbrain to the lower pons. However, the pyramidal tract from midbrain to pons in the affected hemisphere could not be depicted by diffusion tensor tractography at 6 months after stroke onset; instead, only the aberrant pyramidal tract existed for the course of the disappeared pyramidal tract. Results from this study indicate that the main motor functions of the affected extremities appeared to be controlled via the aberrant pyramidal tract with degeneration of the pyramidal tract in the brainstem of the affected hemisphere.展开更多
Very little is known about the effects of transcranial magnetic stimulation and rehabilitation training on pyramidal cell dendrites and synapses of the contralateral, unaffected sensorimotor cortex in a rat model of f...Very little is known about the effects of transcranial magnetic stimulation and rehabilitation training on pyramidal cell dendrites and synapses of the contralateral, unaffected sensorimotor cortex in a rat model of focal cerebral infarct. The present study was designed to explore the mechanisms underlying improved motor function via transcranial magnetic stimulation and rehabilitation training following cerebral infarction. Results showed that rehabilitation training or transcranial magnetic stimulation alone reduced neurological impairment in rats following cerebral infarction, as well as significantly increased synaptic curvatures and post-synaptic density in the non-injured cerebral hemisphere sensorimotor cortex and narrowed the synapse cleft width. In addition, the percentage of perforated synapses increased. The combination of transcranial magnetic stimulation and rehabilitation resulted in significantly increased total dendritic length, dendritic branching points, and dendritic density in layer V pyramidal cells of the non-injured cerebral hemisphere motor cortex. These results demonstrated that transcranial magnetic stimulation and rehabilitation training altered structural parameters of pyramidal cell dendrites and synapses in the non-injured cerebral hemisphere sensorimotor cortex, thereby improving the ability to compensate for neurological functions in rats following cerebral infarction.展开更多
Research on “pyramid power” began in the late 1930s. To date, many documents on “pyramid power” have been published. We have been conducting scientific research on the unexplained “power” of a pyramidal structur...Research on “pyramid power” began in the late 1930s. To date, many documents on “pyramid power” have been published. We have been conducting scientific research on the unexplained “power” of a pyramidal structure (PS) since October 2007. The research focuses on the detection of a non-contact effect of the unexplained “power” of the PS on biosensors (i.e., edible cucumber sections of Cucumis sativus “white spine type”) placed at the top of the PS. In this paper, in particular, we compared the non-contact effect of upper and lower biosensors placed in two layers on the PS apex, and we analyzed the difference of the non-contact effect due to the difference in the layers. The magnitude of the non-contact effect was represented by the calibrated psi index Ψ(E-CAL) calculated from gas concentrations emitted from the biosensors. A method to determine the presence or absence of the non-contact effect by analyzing the gas concentrations was developed by the International Research Institute (IRI). Ψ(E-CAL), which represents the magnitude of the non-contact effect, was the average value of the respective non-contact effect of the upper and lower biosensors stacked in two layers on the PS apex. We conducted the analysis on the assumption that the non-contact effect on the upper and lower biosensors might be different. Therefore, we considered that upper and lower biosensor calibration was required for Ψ(E-CAL), and we introduced a new calibrated psi index Ψ(E-CAL)Layer. Scientifically rigorous experiments to date have detected Ψ(E-CAL) with statistical significance and have demonstrated potential power of the PS (p = 6.0 × 10-3;Welch’s t-test, two-tails, the following p values are also the Welch’s t-test values). Based on data demonstrating the potential power of the PS, we analyzed the non-contact effects on the upper and lower biosensors of the PS apex. We obtained a surprising result that the non-contact effect on the upper biosensors (farther from the PS) was larger than that on the lower biosensors (closer to the PS) (p = 4.0 × 10-7). This suggested that the characteristic of the potential power of the PS, which is considered to exist near the PS apex, is distinctive. We also found that the non-contact effect due to the potential power of the PS varies with the season, and is large in summer and small in winter. In our discussion, we proposed a model that could theoretically explain the experimental results that the non-contact effect on the upper biosensors at the PS apex is larger than the lower biosensors. In proposing this model, we assumed that there were two different types of potential power at the PS apex and that the biosensors had two different gas-generating reactions. In a simulation using the model, the experimental results were well approximated in which the non-contact effect on the biosensors differs depending on the difference between the upper and lower layers. The results of this paper are the world’s first to prove aspects of the “pyramid power” through scientifically rigorous experiments and analysis. These results will become a new field of science in the future, and their broad applications are expected.展开更多
Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar weight.This makes them very suitable for lightweight applications,where high stiffness to weight ratios are needed....Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar weight.This makes them very suitable for lightweight applications,where high stiffness to weight ratios are needed.Most common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the sheets.However,adhesive bonding is prone to delamination,a failure mode that is often difficult to detect.This paper presents the results of delamination testing of fully additive manufactured(AM)AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion(LPBF).The faces and struts are 0.5 mm thick,while the core is 2 mm thick.The inclination of the struts is 45°.To characterise the bonding strength,climbing drum peel tests and out-of-plane tensile tests are performed.Analytical formulas are derived to predict the expected failure loads and modes.The analytics and tests are supported by finite element(FE)calculations.From the analytic approach,design guidelines to avoid delamination in AM sandwich structures are derived.The study presents a critical face sheet thickness to strut diameter ratio for which the structure can delaminate.This ratio is mainly influenced by the inclination of the struts.The peel tests resulted in face yielding,which can also be inferred from the analytics and numerics.The out-of-plane tensile tests didn’t damage the structure.展开更多
There have been various traditions and books which describe a so-called “pyramid power”, but there have been almost no reliable academic studies and no statistically significant data about it. We have continued scie...There have been various traditions and books which describe a so-called “pyramid power”, but there have been almost no reliable academic studies and no statistically significant data about it. We have continued scientifically rigorous experiments using biosensors to elucidate unexplained functions of a pyramidal structure (PS) since 2007. We used edible cucumber sections as biosensors and measured the concentrations of gas emitted from the sections by a technique developed by our group. From them we have demonstrated with high statistical accuracy the existence of the “pyramid power”, which was often recognized as having no scientific basis. We reached two conclusions from the work. 1) The PS converted the unconsciousness of a human (the test subject) more than 6 km away to energy detectable by the biosensors (1% significance). 2) The PS accumulated the influence that a human (the test subject) had when meditating within the PS. Then the PS converted the influence into the energy detectable by the biosensors (10-3% significance). These two conclusions showed that the functions of the PS were detected when “the PS and a human were related”. On the other hand, we hypothesized that the potential power of the PS could be detected even when “the PS and a human were not related”. In this paper, our purpose is to verify the existence of the potential power of the PS alone by experiment when “the PS and a human were not related”. The following three results were obtained by experiment. 1) The presence of the potential power of the PS was demonstrated with 1% significance. 2) The potential power of the PS changed in value between summer and winter, and it was clear that the non-contact effect on the biosensors was larger in summer and smaller in winter. 3) The potential power of the PS affected only the biosensors placed at the PS apex, and did not affect the biosensors placed at the calibration control point 8 m away from the PS. This paper is the first report in the world to show this type of effect by scientific measurements. Our research results may open up a new science field of “pyramid power”, from which we expect further development of fields applying this “pyramid power”.展开更多
Textured magnesium alloys usually exhibit anisotropic mechanical behavior due to the asymmetric activation of different twinning and slipping modes.This work focuses on the pyramidal slip responses of rolled AZ31 magn...Textured magnesium alloys usually exhibit anisotropic mechanical behavior due to the asymmetric activation of different twinning and slipping modes.This work focuses on the pyramidal slip responses of rolled AZ31 magnesium alloy under two loading conditions,compressive and tensile loading along the normal direction.Under the condition where the compressive loading direction is closely parallel to the c-axis of the unit cell,tensile twinning and basal slips are prohibited, dislocations then active and tend to accumulate at grain boundaries and form dislocation walls.Meanwhile,these dislocations exhibit zigzag morphologies,which result from the cross-slip from {10■1} first-order pyramidal plane to {11■2} second-order pyramidal plane,then back to {10■1} first-order pyramidal plane.Under the condition where tensile twins are prevalent,{10■1} first-order and {11■2} second-order pyramidal dislocations are favorable to be activated.Both types of dislocations behave climb-like dissociations onto the basal plane,forming zigzag dislocations.展开更多
OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tiv...OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tive.Here,we hypothesize that dysfunction of central TGR5 may contribute to the pathogene⁃sis of depression.METHODS In well-established chronic social defeat stress(CSDS)and chronic restraint stress(CRS)models of depression,we investigated the functional roles of TGR5 in CA3 pyramidal neurons(PyNs)and underlying mech⁃anisms of the neuronal circuit in depression(for in vivo studies,n=10;for in vitro studies,n=5-10)using fiber photometry;optogenetic,chemoge⁃netic,pharmacological,and molecular profiling techniques;and behavioral tests.RESULTS Both CSDS and CRS most significantly reduced TGR5 expression of hippocampal CA3 PyNs.Genetic overexpression of TGR5 in CA3 PyNs or intra-CA3 infusion of INT-777,a specific agonist,protected against CSDS and CRS,exerting sig⁃nificant antidepressant-like effects that were mediated via CA3 PyN activation.Conversely,genetic knockout or TGR5 knockdown in CA3 facilitated stress-induced depression-like behav⁃iors.Re-expression of TGR5 in CA3 PyNs rather than infusion of INT-777 significantly improved depression-like behaviors in Tgr5 knockout mice exposed to CSDS or CRS.Silencing and stimula⁃tion of CA3 PyNs→somatostatin-GABAergic(gamma-aminobutyric acidergic)neurons of the dorsolateral septum circuit bidirectionally regulat⁃ed depression-like behaviors,and blockade of this circuit abrogated the antidepressant-like effects from TGR5 activation of CA3 PyNs.CON⁃CLUSION TGR5 can regulate depression via CA3 PyNs→somatostatin-GABAergic neurons of dorsolateral septum transmission,suggesting that TGR5 could be a novel target for developing antidepressants.展开更多
The effect of the face thickness to core height ratio on different multi-layer pyramidal core sandwich columns under in-plane compression is investigated theoretically and numerically. Numerical simulation is in good ...The effect of the face thickness to core height ratio on different multi-layer pyramidal core sandwich columns under in-plane compression is investigated theoretically and numerically. Numerical simulation is in good agreement with theory. Results indicate that one specified face thickness to core height ratio corresponds to one optimum layer number of multi-layer pyramidal core sandwich columns in consideration of engineering application. This result can guide the sandwich structure design.展开更多
The aberrant pyramidal tract is the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 21-year-old man presented with right hemiparesis due to a traumatic intracerebral hemorrha...The aberrant pyramidal tract is the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 21-year-old man presented with right hemiparesis due to a traumatic intracerebral hemorrhage in the left corona radiata. His motor function recovered almost to the normal state at 10 months after onset. Through diffusion tensor tractography, the pyramidal tract in the affected （left） hemisphere showed discontinuation at the pontine level at 13 months after onset. An aberrant pyramidal tract was observed, which originated from the primary motor cortex and the supplementary motor area and descended through the corona radiata, then through the posterior limb of the internal capsule and the medial lemniscus pathway from the midbrain to the pons, finally entered into the pyramidal tract area at the pontomedullary junction, it suggests that the motor functions of the right extremities in this patient had recovered by this aberrant pyramidal tract.展开更多
Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify the pyramid effects by the PS in...Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify the pyramid effects by the PS into the following two types. (i) The pyramid effects in which the PS converted the test subject’s unexplained energy to affect biosensors when the test subject entered the PS and meditated. (ii) The pyramid effects in which the potential power of the PS affect</span><span style="font-family:Verdana;">ed</span><span style="font-family:Verdana;"> biosensors if the test subject ha</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> not been inside the PS for at least 20 days and the test subject’s unexplained energy was excluded. In this paper, we report new results regarding (ii). As a result of dividing a year according to the four seasons of winter, spring, summer, and autumn and analyzing the pyramid effect of each period, the following points were found. 1) There was a pyramid effect without seasonal variation. The pyramid effect on the lower and upper layers was different throughout the year for the biosensors placed at the PS apex in two layers, regardless of the season. 2) There was a pyramid effect with seasonal variation. The value of the psi index, which indicates the magnitude of the pyramid effect, changed as the seasons changed, while different pyramid effects were maintained on the lower and upper layers. Regarding the change in the pyramid effect depending on the season, the psi index in summer was larger than that in winter in both the lower and upper layers. From these results, we found that there are two types of potential power at the PS apex: seasonal potential power and non-seasonal potential power.展开更多
The presence of the aberrant pyramidal tract has been demonstrated by several studies; however, little is known about its role in motor recovery in stroke patients. In the present study, we reported a 69-year-old righ...The presence of the aberrant pyramidal tract has been demonstrated by several studies; however, little is known about its role in motor recovery in stroke patients. In the present study, we reported a 69-year-old right-handed female patient with an infarct in the mid to lateral portion of the left cerebra peduncle, who showed an aberrant pyramidal tract by diffusion tensor tractography. The patient presented with severe weakness of the right extremities at stroke onset. The patient showed progressive motor recovery as much as being able to extend the affected extremities against some resistance at 6 months after onset. At 20 months after stroke onset, motor function of the left extremities had recovered to a nearly normal state. Diffusion tensor tractography results showed that the PT was disrupted at the lower midbrain of the affected （left） hemisphere at 3 weeks after stroke onset and this disruption was not changed at 20 months. An aberrant pyramidal tract in the left hemisphere was also observed, which originated from the primary motor cortex and descended through the corona radiata, posterior limb of the internal capsule, thalamus, the medial lemniscus pathway from the midbrain to the pons, and then entered into the pyramidal tract area at the pontomedullary junction. Transcranial magnetic stimulation did not elicit motor evoked potential from the affected hand muscle at 3 weeks, but it elicited motor evoked potential with mildly delayed latency and low amplitude in the affected hand muscle at 20 months. The main motor functions of the affected extremities in this patient appeared to be recovered via this aberrant pyramidal tract.展开更多
基金financially supported by National Natural Science Foundation of China(12072211,12232008)Foundation of Key laboratory(2022JCJQLB05703)Sichuan Province Science and Technology Project(2023NSFSC0914)。
文摘Pyramidal dislocations are important for ductility enhancement of magnesium alloys.In this work,molecular dynamics simulations were employed to study the gliding behavior of pyramidal(c+a)dislocations under c-axis compressive loading and tensile loading.The Peierls stress of Py-Ⅰ dislocation shows strong tension-compression asymmetry.However,no tension-compression asymmetry is seen on the Py-Ⅱ dislocation and basal dislocation.The tension-compression asymmetry origins from the asymmetry of partial dislocations of Py-Ⅰ dislocation,which leads to the dislocation core contracted under c-axis compressive loading and expanded under tensile loading.By analyzing the forces acting on the partial dislocations,we defined a neutral direction,which deviates from the full dislocation Burgers vector by 70.3°.The neutral direction is dependent on the ratio of lattice stresses of partial dislocations.If the shear stress is applied along the neutral direction,tension-compression asymmetry is eliminated and the dislocation core is un-contracted/un-expanded.The neutral direction of symmetrical dislocations(Py-Ⅱ dislocation and basal dislocation)is just the full dislocation Burgers vector.The tension-compression asymmetry and dislocation core contraction/expansion have an important influence on the dislocation behaviors,such as cross-slip,decomposition,basaltransition and mobility,which can be used to explain the mechanical behaviors of Mg single-crystals compressed along c-axis.
基金The Third Xinjiang Scientific Expedition and Research Program:Investigation and Risk Assessment of Drought and Aeolian Disasters in Tarim River Basin,No.2021xjkk0300Xinjiang Tianshan Talent Program,No.2022TSYCLJ0002National Natural Science Foundation of China,No.42471013。
文摘As the largest desert in China,the Taklimakan Desert features unique mobility and alternating mega-dune and inter-dune landscapes with rich dune types.Most areas of the sand sea were explored in the early 20th century.However,the eastern Taklimakan Desert characterized by extremely tall dunes,had received little attention until 2022 owing to transportation inconveniences.This study examined the alternating mega-dune and inter-dune landscapes in the eastern Taklimakan Desert,through spatial analysis and field surveys.Results demonstrate that the tallest mega-dunes are distributed primarily to the east of the central desert,with the occurrence of approximately 240 mega-dunes exceeding 150 m in height.The height-spacing relationship of mega-dunes with different orders exhibits a weak correlation,suggesting that the dune formation and evolution are more complex than previously documented;this could be attributed to the factors other than solely the wind regime.Additionally,from the field survey,we found that sand availability is the dominant factor for constraining the sustained growth of mega-dunes.A pattern coarsening may be responsible for the development of the dune fields in the eastern Taklimakan Desert,thus yielding constraints on the development of mega-dunes,and other dune fields on Earth as well.
基金by the Deutsche Forschungsgemeinschaft(DFG)through projects 420149269,394480829as part of the CRC1394“Structural and Chemical Atomic Complexity-From Defect Phase Diagrams to Material Properties”(project 409476157).
文摘Dynamic recrystallization(DRX)in inhomogeneous deformation zones,such as grain boundaries,shear bands,and deformation bands,is critical for texture modification in magnesium alloys during deformation at elevated temperatures.This study investigates the DRX mechanisms in AZWX3100 magnesium alloy under plane strain compression at 200℃.Microstructural analysis revealed necklace-type DRX accompanied by evidence of local grain boundary bulging.Additionally,ribbons of recrystallized grains were observed withinfine deformation bands,aligned with theoretical pyramidal I and II slip traces derived from the matrix.The distribution of local misorientation within the deformed microstructure demonstrated a clear association between deformation bands and localized strain.Dislocation analysis of lamellar specimens extracted from two pyramidal slip bands revealed<c+a>dislocations,indicating a connection between<c+a>slip activation and the formation of deformation bands.Crystal plasticity simulations suggest that the orientation of deformation bands is responsible for the unique recrystallization texture of the DRX grains within these bands.The texture characteristics imply a progressive,glide-induced DRX mechanism.A fundamental understanding of the role of deformation bands in texture modification can facilitate future alloy and process design.
文摘Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a computational investigation of a novel Multi-Focal Pyramidal Array(MFPA)-based CPV system designed to overcome this limitation.The MFPA architecture employs a geometrically optimized pyramidal concentrator to distribute concen-trated sunlight onto strategically placed,low-cost monocrystalline silicon cells,enabling high efficiency energy capture while passively managing thermal loads.Coupled optical thermal electrical simulations in COMSOL Multiphysics demonstrate a geometric concentration ratio of 120×,with system temperatures maintained below 110℃ under standard 1000 W/m2 Direct Normal Irradiance(DNI).Ray tracing confirms 95%optical efficiency and a concentrated light spot radius of 2.48 mm.Compared with conventional CPV designs,the MFPA improves power-per-cost by 25%and reduces tracking requirements by 50%owing to its wide±15°acceptance angle.These results highlight the MFPA’s potential as a scalable,low-cost,and energy-efficient pathway for expanding solar power generation.
文摘Dear Editor,The importance of the medial entorhinal cortex(MEC)for memory and spatial navigation has been shown repeatedly in many species,including mice and humans[1,2].It is,therefore,not surprising that the connectivity of this structure has been studied extensively over the past century,mainly using a range of anterograde and retrograde anatomical tracers[3].
基金supported by the National Natural Science Foundation of China(No.62203163)the Scientific Research Project of Hunan Provincial Education Department(No.24A0519)+1 种基金the Hunan Provincial Natural Science Foundation(No.2025JJ60407)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX2024100).
文摘Accurate detection of smoke and fire sources is critical for early fire warning and environmental monitoring.However,conventional detection approaches are highly susceptible to noise,illumination variations,and complex environmental conditions,which often reduce detection accuracy and real-time performance.To address these limitations,we propose Lightweight and Precise YOLO(LP-YOLO),a high-precision detection framework that integrates a self-attention mechanism with a feature pyramid,built upon YOLOv8.First,to overcome the restricted receptive field and parameter redundancy of conventional Convolutional Neural Networks(CNNs),we design an enhanced backbone based on Wavelet Convolutions(WTConv),which expands the receptive field through multifrequency convolutional processing.Second,a Bidirectional Feature Pyramid Network(BiFPN)is employed to achieve bidirectional feature fusion,enhancing the representation of smoke features across scales.Third,to mitigate the challenge of ambiguous object boundaries,we introduce the Frequency-aware Feature Fusion(FreqFusion)module,in which the Adaptive Low-Pass Filter(ALPF)reduces intra-class inconsistencies,the offset generator refines boundary localization,and the Adaptive High-Pass Filter(AHPF)recovers high-frequency details lost during down-sampling.Experimental evaluations demonstrate that LP-YOLO significantly outperforms the baseline YOLOv8,achieving an improvement of 9.3%in mAP@50 and 9.2%in F1-score.Moreover,the model is 56.6%and 32.4%smaller than YOLOv7-tiny and EfficientDet,respectively,while maintaining real-time inference speed at 238 frames per second(FPS).Validation on multiple benchmark datasets,including D-Fire,FIRESENSE,and BoWFire,further confirms its robustness and generalization ability,with detection accuracy consistently exceeding 82%.These results highlight the potential of LP-YOLO as a practical solution with high accuracy,robustness,and real-time performance for smoke and fire source detection.
基金supported by the National Natural Science Foundation of China under Grant Nos.90816024 and 10872059the Major State Basic Research Development Program of China under Grant No. 2011CB610303+2 种基金the Fundamental Research Funds for the central Universities grant No. HIT. NSRIF. 2010069the Program of Excellent Team in Harbin Institute of Technologythe Program for New Century Excellent Talents in University under Grant No.NCET-08-0152
文摘The mechanical performance of an all-composite pyramidal lattice truss core sandwich structure was investigated both theoretically and experimentally.Sandwich structures were fabricated with a hot compression molding method using carbon fiber reinforced composite T700/3234.The out-of-plane compression and shear tests were conducted.Experimental results showed that the all-composite pyramidal lattice truss core sandwich structures were more weight efficient than other metallic lattice truss core sandwich structures.Failure modes revealed that node rupture dominated the mechanical behavior of sandwich structures.
基金Project supported by the National Natural Science Foundation of China(Nos.11572007 and 11172084)
文摘The equation of motion of sandwich beam with pyramidal lattice core in the supersonic flow considering geometric nonlinearity is formulated using Hamilton＇s principle. The piston theory is used to evaluate aerodynamic pressure. The structural aeroelastic properties are analyzed using frequency- and time-domain methods, and some interesting phenomena are observed. It is noted that the flutter of sandwich beam occurs under the coupling effect of low order modes. The critical flutter aerodynamic pressure of the sandwich beam is higher than that of the isotropic beam with the same weight, length and width. The influence of inclination angle of core truss on flutter characteristic is analyzed.
基金supported by the National Natural Science Foundation of China (41530745, 41371114, 41361004)the State Key Laboratory Breeding Base of Desertification and Aeolian Sand Disaster Combating,Gansu Desert Control Research Institute for providing support for sample testing
文摘The complex interactions in desert ecosystems between functional types and environmental conditions could be reflected by plant water use patterns. However, the mechanisms underlying the water use patterns as well as the water sources of Tamarix laxa in the mega-dunes of the Badain Jaran Desert, China, remain unclear. This study investigated the water sources and water use patterns of T. laxa using the stable oxygen isotope method. The δ18O values of xylem water, soil water in different layers(0–200 cm), rainwater, snow water, lake water, atmospheric water vapor, condensate water, and groundwater were measured. The sources of water used by T. laxa were determined using the IsoSource model. The results indicate that T. laxa mainly relies on soil water. At the beginning of the growing season(in May), the species is primarily dependent on water from the middle soil layer(60–120 cm) and deep soil layer(120–200 cm). However, it mainly absorbs water from the shallow soil layer(0–60 cm) as the rainy season commences. In September, water use of T. laxa reverts to the deep soil layer(120–200 cm). The water use patterns of T. laxa are closely linked with heavy precipitation events and soil water content. These findings reveal the drought resistance mechanisms of T. laxa and are of significance for screening species for ecological restoration.
基金the National Research Foundation of Korea Grant funded by the Korean Government,No. KRF-2008-314-E00173
文摘The aberrant pyramidal tract refers to the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 63-year-old male patient presented with severe paralysis of the left extremities due to a right corona radiata infarct. He was able to extend the affected fingers against resistance at 2 months after stroke onset. At 6 months after stroke onset, he was able to perform some fine motor activities, as well as to walk with a nearly normal gait. Functional MRI, which was performed at 6 months after onset, showed that the contralateral primary sensorimotor cortex was activated during affected （left） hand movements. Diffusion tensor tractography results showed that at 2 weeks after stroke onset, pyramidal tracts of the affected hemisphere originated from the primary motor cortex and descended along the known pathway of the pyramidal tract with an aberrant pyramidal tract, which was bypassed through the medial lemniscus from the midbrain to the lower pons. However, the pyramidal tract from midbrain to pons in the affected hemisphere could not be depicted by diffusion tensor tractography at 6 months after stroke onset; instead, only the aberrant pyramidal tract existed for the course of the disappeared pyramidal tract. Results from this study indicate that the main motor functions of the affected extremities appeared to be controlled via the aberrant pyramidal tract with degeneration of the pyramidal tract in the brainstem of the affected hemisphere.
基金Yantai Science and Technology Development Projects, No. 2008142-5
文摘Very little is known about the effects of transcranial magnetic stimulation and rehabilitation training on pyramidal cell dendrites and synapses of the contralateral, unaffected sensorimotor cortex in a rat model of focal cerebral infarct. The present study was designed to explore the mechanisms underlying improved motor function via transcranial magnetic stimulation and rehabilitation training following cerebral infarction. Results showed that rehabilitation training or transcranial magnetic stimulation alone reduced neurological impairment in rats following cerebral infarction, as well as significantly increased synaptic curvatures and post-synaptic density in the non-injured cerebral hemisphere sensorimotor cortex and narrowed the synapse cleft width. In addition, the percentage of perforated synapses increased. The combination of transcranial magnetic stimulation and rehabilitation resulted in significantly increased total dendritic length, dendritic branching points, and dendritic density in layer V pyramidal cells of the non-injured cerebral hemisphere motor cortex. These results demonstrated that transcranial magnetic stimulation and rehabilitation training altered structural parameters of pyramidal cell dendrites and synapses in the non-injured cerebral hemisphere sensorimotor cortex, thereby improving the ability to compensate for neurological functions in rats following cerebral infarction.
文摘Research on “pyramid power” began in the late 1930s. To date, many documents on “pyramid power” have been published. We have been conducting scientific research on the unexplained “power” of a pyramidal structure (PS) since October 2007. The research focuses on the detection of a non-contact effect of the unexplained “power” of the PS on biosensors (i.e., edible cucumber sections of Cucumis sativus “white spine type”) placed at the top of the PS. In this paper, in particular, we compared the non-contact effect of upper and lower biosensors placed in two layers on the PS apex, and we analyzed the difference of the non-contact effect due to the difference in the layers. The magnitude of the non-contact effect was represented by the calibrated psi index Ψ(E-CAL) calculated from gas concentrations emitted from the biosensors. A method to determine the presence or absence of the non-contact effect by analyzing the gas concentrations was developed by the International Research Institute (IRI). Ψ(E-CAL), which represents the magnitude of the non-contact effect, was the average value of the respective non-contact effect of the upper and lower biosensors stacked in two layers on the PS apex. We conducted the analysis on the assumption that the non-contact effect on the upper and lower biosensors might be different. Therefore, we considered that upper and lower biosensor calibration was required for Ψ(E-CAL), and we introduced a new calibrated psi index Ψ(E-CAL)Layer. Scientifically rigorous experiments to date have detected Ψ(E-CAL) with statistical significance and have demonstrated potential power of the PS (p = 6.0 × 10-3;Welch’s t-test, two-tails, the following p values are also the Welch’s t-test values). Based on data demonstrating the potential power of the PS, we analyzed the non-contact effects on the upper and lower biosensors of the PS apex. We obtained a surprising result that the non-contact effect on the upper biosensors (farther from the PS) was larger than that on the lower biosensors (closer to the PS) (p = 4.0 × 10-7). This suggested that the characteristic of the potential power of the PS, which is considered to exist near the PS apex, is distinctive. We also found that the non-contact effect due to the potential power of the PS varies with the season, and is large in summer and small in winter. In our discussion, we proposed a model that could theoretically explain the experimental results that the non-contact effect on the upper biosensors at the PS apex is larger than the lower biosensors. In proposing this model, we assumed that there were two different types of potential power at the PS apex and that the biosensors had two different gas-generating reactions. In a simulation using the model, the experimental results were well approximated in which the non-contact effect on the biosensors differs depending on the difference between the upper and lower layers. The results of this paper are the world’s first to prove aspects of the “pyramid power” through scientifically rigorous experiments and analysis. These results will become a new field of science in the future, and their broad applications are expected.
基金Part of this work was supported by the German Federal Ministry for Economic Affairs and Energy(BMWi)(Grant No.20E1713B).
文摘Sandwich structures possess a high bending stiffness compared to monolithic structures with a similar weight.This makes them very suitable for lightweight applications,where high stiffness to weight ratios are needed.Most common manufacturing methods of sandwich structures involve adhesive bonding of the core material with the sheets.However,adhesive bonding is prone to delamination,a failure mode that is often difficult to detect.This paper presents the results of delamination testing of fully additive manufactured(AM)AlSi10Mg sandwich structures with pyramidal lattice truss core using Laser Powder Bed Fusion(LPBF).The faces and struts are 0.5 mm thick,while the core is 2 mm thick.The inclination of the struts is 45°.To characterise the bonding strength,climbing drum peel tests and out-of-plane tensile tests are performed.Analytical formulas are derived to predict the expected failure loads and modes.The analytics and tests are supported by finite element(FE)calculations.From the analytic approach,design guidelines to avoid delamination in AM sandwich structures are derived.The study presents a critical face sheet thickness to strut diameter ratio for which the structure can delaminate.This ratio is mainly influenced by the inclination of the struts.The peel tests resulted in face yielding,which can also be inferred from the analytics and numerics.The out-of-plane tensile tests didn’t damage the structure.
文摘There have been various traditions and books which describe a so-called “pyramid power”, but there have been almost no reliable academic studies and no statistically significant data about it. We have continued scientifically rigorous experiments using biosensors to elucidate unexplained functions of a pyramidal structure (PS) since 2007. We used edible cucumber sections as biosensors and measured the concentrations of gas emitted from the sections by a technique developed by our group. From them we have demonstrated with high statistical accuracy the existence of the “pyramid power”, which was often recognized as having no scientific basis. We reached two conclusions from the work. 1) The PS converted the unconsciousness of a human (the test subject) more than 6 km away to energy detectable by the biosensors (1% significance). 2) The PS accumulated the influence that a human (the test subject) had when meditating within the PS. Then the PS converted the influence into the energy detectable by the biosensors (10-3% significance). These two conclusions showed that the functions of the PS were detected when “the PS and a human were related”. On the other hand, we hypothesized that the potential power of the PS could be detected even when “the PS and a human were not related”. In this paper, our purpose is to verify the existence of the potential power of the PS alone by experiment when “the PS and a human were not related”. The following three results were obtained by experiment. 1) The presence of the potential power of the PS was demonstrated with 1% significance. 2) The potential power of the PS changed in value between summer and winter, and it was clear that the non-contact effect on the biosensors was larger in summer and smaller in winter. 3) The potential power of the PS affected only the biosensors placed at the PS apex, and did not affect the biosensors placed at the calibration control point 8 m away from the PS. This paper is the first report in the world to show this type of effect by scientific measurements. Our research results may open up a new science field of “pyramid power”, from which we expect further development of fields applying this “pyramid power”.
基金supported by the Bejing Municipal Natural Science Foundation (No.2214072)the Interdisciplinary Research Project for Young Teachers of USTB (Fundamental Research Funds for the Central Universities) (FRF-IDRY-20-034)the Office of China Postdoctoral Council under Award No.YJ20200248。
文摘Textured magnesium alloys usually exhibit anisotropic mechanical behavior due to the asymmetric activation of different twinning and slipping modes.This work focuses on the pyramidal slip responses of rolled AZ31 magnesium alloy under two loading conditions,compressive and tensile loading along the normal direction.Under the condition where the compressive loading direction is closely parallel to the c-axis of the unit cell,tensile twinning and basal slips are prohibited, dislocations then active and tend to accumulate at grain boundaries and form dislocation walls.Meanwhile,these dislocations exhibit zigzag morphologies,which result from the cross-slip from {10■1} first-order pyramidal plane to {11■2} second-order pyramidal plane,then back to {10■1} first-order pyramidal plane.Under the condition where tensile twins are prevalent,{10■1} first-order and {11■2} second-order pyramidal dislocations are favorable to be activated.Both types of dislocations behave climb-like dissociations onto the basal plane,forming zigzag dislocations.
文摘OBJECTIVE Takeda G protein-coupled receptor 5(TGR5)is recognized as a promising target for type 2 diabetes and metabolic syndrome;its expression has been demonstrat⁃ed in the brain and is thought to be neuroprotec⁃tive.Here,we hypothesize that dysfunction of central TGR5 may contribute to the pathogene⁃sis of depression.METHODS In well-established chronic social defeat stress(CSDS)and chronic restraint stress(CRS)models of depression,we investigated the functional roles of TGR5 in CA3 pyramidal neurons(PyNs)and underlying mech⁃anisms of the neuronal circuit in depression(for in vivo studies,n=10;for in vitro studies,n=5-10)using fiber photometry;optogenetic,chemoge⁃netic,pharmacological,and molecular profiling techniques;and behavioral tests.RESULTS Both CSDS and CRS most significantly reduced TGR5 expression of hippocampal CA3 PyNs.Genetic overexpression of TGR5 in CA3 PyNs or intra-CA3 infusion of INT-777,a specific agonist,protected against CSDS and CRS,exerting sig⁃nificant antidepressant-like effects that were mediated via CA3 PyN activation.Conversely,genetic knockout or TGR5 knockdown in CA3 facilitated stress-induced depression-like behav⁃iors.Re-expression of TGR5 in CA3 PyNs rather than infusion of INT-777 significantly improved depression-like behaviors in Tgr5 knockout mice exposed to CSDS or CRS.Silencing and stimula⁃tion of CA3 PyNs→somatostatin-GABAergic(gamma-aminobutyric acidergic)neurons of the dorsolateral septum circuit bidirectionally regulat⁃ed depression-like behaviors,and blockade of this circuit abrogated the antidepressant-like effects from TGR5 activation of CA3 PyNs.CON⁃CLUSION TGR5 can regulate depression via CA3 PyNs→somatostatin-GABAergic neurons of dorsolateral septum transmission,suggesting that TGR5 could be a novel target for developing antidepressants.
基金supported by the National Natural Science Foundation of China under Grant No. 11432004
文摘The effect of the face thickness to core height ratio on different multi-layer pyramidal core sandwich columns under in-plane compression is investigated theoretically and numerically. Numerical simulation is in good agreement with theory. Results indicate that one specified face thickness to core height ratio corresponds to one optimum layer number of multi-layer pyramidal core sandwich columns in consideration of engineering application. This result can guide the sandwich structure design.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology,No.2012R1A1A4A01001873
文摘The aberrant pyramidal tract is the collateral pathway of the pyramidal tract through the medial lemniscus in the brainstem. A 21-year-old man presented with right hemiparesis due to a traumatic intracerebral hemorrhage in the left corona radiata. His motor function recovered almost to the normal state at 10 months after onset. Through diffusion tensor tractography, the pyramidal tract in the affected （left） hemisphere showed discontinuation at the pontine level at 13 months after onset. An aberrant pyramidal tract was observed, which originated from the primary motor cortex and the supplementary motor area and descended through the corona radiata, then through the posterior limb of the internal capsule and the medial lemniscus pathway from the midbrain to the pons, finally entered into the pyramidal tract area at the pontomedullary junction, it suggests that the motor functions of the right extremities in this patient had recovered by this aberrant pyramidal tract.
文摘Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify the pyramid effects by the PS into the following two types. (i) The pyramid effects in which the PS converted the test subject’s unexplained energy to affect biosensors when the test subject entered the PS and meditated. (ii) The pyramid effects in which the potential power of the PS affect</span><span style="font-family:Verdana;">ed</span><span style="font-family:Verdana;"> biosensors if the test subject ha</span><span style="font-family:Verdana;">d</span><span style="font-family:Verdana;"> not been inside the PS for at least 20 days and the test subject’s unexplained energy was excluded. In this paper, we report new results regarding (ii). As a result of dividing a year according to the four seasons of winter, spring, summer, and autumn and analyzing the pyramid effect of each period, the following points were found. 1) There was a pyramid effect without seasonal variation. The pyramid effect on the lower and upper layers was different throughout the year for the biosensors placed at the PS apex in two layers, regardless of the season. 2) There was a pyramid effect with seasonal variation. The value of the psi index, which indicates the magnitude of the pyramid effect, changed as the seasons changed, while different pyramid effects were maintained on the lower and upper layers. Regarding the change in the pyramid effect depending on the season, the psi index in summer was larger than that in winter in both the lower and upper layers. From these results, we found that there are two types of potential power at the PS apex: seasonal potential power and non-seasonal potential power.
基金a grant from Daegu Metropolitan City R&D Project
文摘The presence of the aberrant pyramidal tract has been demonstrated by several studies; however, little is known about its role in motor recovery in stroke patients. In the present study, we reported a 69-year-old right-handed female patient with an infarct in the mid to lateral portion of the left cerebra peduncle, who showed an aberrant pyramidal tract by diffusion tensor tractography. The patient presented with severe weakness of the right extremities at stroke onset. The patient showed progressive motor recovery as much as being able to extend the affected extremities against some resistance at 6 months after onset. At 20 months after stroke onset, motor function of the left extremities had recovered to a nearly normal state. Diffusion tensor tractography results showed that the PT was disrupted at the lower midbrain of the affected （left） hemisphere at 3 weeks after stroke onset and this disruption was not changed at 20 months. An aberrant pyramidal tract in the left hemisphere was also observed, which originated from the primary motor cortex and descended through the corona radiata, posterior limb of the internal capsule, thalamus, the medial lemniscus pathway from the midbrain to the pons, and then entered into the pyramidal tract area at the pontomedullary junction. Transcranial magnetic stimulation did not elicit motor evoked potential from the affected hand muscle at 3 weeks, but it elicited motor evoked potential with mildly delayed latency and low amplitude in the affected hand muscle at 20 months. The main motor functions of the affected extremities in this patient appeared to be recovered via this aberrant pyramidal tract.
