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Magnetic pulse welding of Al-5754 with Al-7075 and MARS 380:Weldability windows and ballistic testing
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作者 Benoit Lagain Thomas Heuzé +1 位作者 Guillaume Racineux Michel Arrigoni 《Defence Technology(防务技术)》 2026年第1期64-79,共16页
Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining... Joining dissimilar materials encounters significant engineering challenges due to the contrast in material properties that makes conventional welding not feasible.Magnetic Pulse Welding(MPW)offers a solidstate joining technique that overcomes these issues by using impact to create strong bonds without melting the substrate materials.This study investigates the weldability of aluminum alloy Al-5754 with Al-7075 and MARS 380 steel,used in armouring solutions of defense systems,by the use of MPW.In this work,weldability windows are investigated by varying standoff distances between the coating material and its substrate(0.25-4.5 mm)and discharge energies(5-13 kJ)with both O-shape and U-shape inductors.Mechanical strength of the welded joints were assessed through single lap shear tests,identifying optimal welding parameters.Then,the velocity profiles of the flyer plates were measured using heterodyne velocimetry to understand the dynamics of the impact.Then,substructures assembled with the optimal welding conditions were subjected to ballistic testing using 7.62 mm×51 mm NATO and 9 mm×19 mm Parabellum munitions to evaluate the resilience of the welds under ballistic impact.The outcomes demonstrate that MPW effectively joins Al-5754 with both Al-7075 and MARS 380,producing robust welds capable of withstanding ballistic impacts under certain conditions.This research advances the application of MPW in lightweight ballistic protection of defense systems,contributing to the development of more resilient and lighter protective structures. 展开更多
关键词 Magnetic pulse welding(MPW) Dissimilar material joining Weldability windows Impact welding Ballistic testing
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Beyond paralysis:Impact of spinal cord injury on brain inflammation and cognitive function through cell therapy
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作者 Quentin Delarue Nicolas Guérout 《Neural Regeneration Research》 2026年第6期2347-2348,共2页
Traumatic spinal cord injury(SCI)is a pathological condition that impairs both sensorimotor and cognitive functions.While research has long focused on understanding the pathophysiology of SCI and developing treatments... Traumatic spinal cord injury(SCI)is a pathological condition that impairs both sensorimotor and cognitive functions.While research has long focused on understanding the pathophysiology of SCI and developing treatments,only a few studies have investigated the cellular and molecular consequences that occur in the brain after trauma.From the earliest stages,the injury triggers microglial activation,increased neuronal death,and reduced hippocampal neurogenesis in the dentate gyrus. 展开更多
关键词 reduced hippocampal neurogenesis celltherapy dentate gyrus cognitivefunction braininflammation cellular molecular consequences spinalcordinjury traumatic spinal cord injury sci
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Secretase inhibition in Alzheimer's disease therapeutics reveals functional roles of amyloid-beta42
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作者 Timothy Daly Bruno P.Imbimbo 《Neural Regeneration Research》 2026年第5期2003-2004,共2页
In the words of the late Sir Colin Blakemore,neurologists have historically sought to infer brain functions in a manner akin to to king a hammer to a computeranalyzing localized anatomical lesions caused by trauma,tum... In the words of the late Sir Colin Blakemore,neurologists have historically sought to infer brain functions in a manner akin to to king a hammer to a computeranalyzing localized anatomical lesions caused by trauma,tumors,or strokes,noting deficits,and inferring what functions certain brain regions may be responsible for.This approach exemplifies a deletion heuristic,where the absence of a specific function reveals insights about the underlying structures or mechanisms responsible for it.By observing what is lost when a particular brain region is damaged,throughout the history of the field,neurologists have pieced together the intricate relationship between anatomy and function. 展开更多
关键词 infer brain functions secretase inhibition Alzheimers disease therapeutics king hammer deletion heuristic amyloid beta deletion heuristicwhere observing what l
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Prolonged survival and risk factors for reintervention after inflatable penile prosthesis implantation
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作者 Skander Zouari Flora Barthe +7 位作者 Arnoult Morrone Lionel Mendel Imad Bentellis Louis Vignot Romain Haider Younes Ahallal Daniel Chevallier Matthieu Durand 《The Canadian Journal of Urology》 2026年第1期173-184,共12页
Background:Inflatable Penile Prosthesis(IPP)is the treatment for erectile dysfunction(ED)refractory to pharmacological therapies.Long-term data on factors associated with prosthesis survival remain unclear.This study ... Background:Inflatable Penile Prosthesis(IPP)is the treatment for erectile dysfunction(ED)refractory to pharmacological therapies.Long-term data on factors associated with prosthesis survival remain unclear.This study aimed to analyze the long-term survival of penile prostheses and identify risk factors associated with survival without reintervention.Methods:This is a retrospective,single-center study of patients who underwent IPP implantation between January 2014 and December 2022.Preoperative data related to the patient and the etiology of ED,as well as perioperative data,were collected.The primary outcome was survival without reintervention,defined as prosthesis revision or explantation due to mechanical dysfunction or infection.We conducted survival analyses without reintervention and searched for risk factors using a multivariate Cox model.Results:In total,33 out of 137 patients underwent reintervention(24.1%),including 24(17.5%)prosthesis revisions and 9(6.6%)had explantations.Median follow-up was 39 months with an interquartile range(IQR)of 9.00 to 62.00.Median survival without reintervention was 7 years.In univariate analysis,downsizing(p=0.046)was associated with reintervention.Smoking(p=0.003)and age(p=0.034)were associated with prosthesis explantation.The number of implantations(p=0.009)was associated with prosthesis revision.Multivariate analysis by the Cox model did not identify any independent predictive factors for reintervention.Conclusion:Smoking may play a role in infection post-IPP implantation.Primary implantations seem to be associated with better survival.Adjusting cylinder size,known as downsizing,is likely to be a proxy for the complexity of the procedure and thus linked to earlier reintervention. 展开更多
关键词 erectile dysfunction mechanical dysfunction implant survival inflatable penile prosthesis long-term follow-up surgical reoperation
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Novel Statistical Shape Relation and Prediction of Personalized Female Pelvis,Pelvic Floor,and Perineal Muscle Shapes
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作者 Tan-Nhu Nguyen Trong-Pham Nguyen-Huu Tien-Tuan Dao 《Computer Modeling in Engineering & Sciences》 2026年第2期1-47,共47页
Vaginal delivery is a fascinating physiological process,but also a high-risk process.Up to 85%–90%of vaginal deliveries lead to perineal trauma,with nearly 11%of severe perineal tearing.It is a common occurrence,espe... Vaginal delivery is a fascinating physiological process,but also a high-risk process.Up to 85%–90%of vaginal deliveries lead to perineal trauma,with nearly 11%of severe perineal tearing.It is a common occurrence,especially for first-time mothers.Computational childbirth plays an essential role in the prediction and prevention of these traumas,but fast personalization of the pelvis and floor muscles is challenging due to their anatomical complexity.This study introduces a novel shape-prediction-based personalization of the pelvis and floor muscles for perineal tearing management and childbirth simulation.300 subjects were selected from public Computed Tomography(CT)databases.The pelvic bone nmjmeshes were generated using a coarse-to-fine non-rigid mesh alignment procedure.The floor muscle meshes were personalized using the bone mesh deformation information.A feature-to-pelvic structure reconstruction pipeline was proposed,incorporating various strategies.Ten-fold cross-validation helped determine the optimal reconstruction strategy,regression method,and feature sizes.The mesh-to-mesh distance metric was employed for evaluating.The statistical shape relation-based strategy,coupled with multi-output ridge regression,was the optimal approach for pelvic structure reconstruction.With a feature set ranging from 3 to 38,the mean errors were 2.672 to 1.613 mm,and 3.237 to 1.415 mm in muscle attachment regions.The best-and worst-case predictions had errors of 1.227±0.959 mm and 2.900±2.309 mm,respectively.This study provides a novel approach to achieving fast personalized childbirth modeling and simulation for perineal tearing management. 展开更多
关键词 Personalized statistical shape relation shape prediction female pelvis shape pelvic floor and perineal tissue shape
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Surface seismic amplification in the presence of underground tunnels with an overlying tire-derived aggregate layer
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作者 Hou Menghao Sun Qiangqiang Daniel Dias 《Earthquake Engineering and Engineering Vibration》 2026年第1期237-254,共18页
Tire-derived aggregate(TDA)is an engineered construction material produced from recycled scrap tires and is often used as a compressible layer overlying buried structures to reduce overburden loads.The potential ampli... Tire-derived aggregate(TDA)is an engineered construction material produced from recycled scrap tires and is often used as a compressible layer overlying buried structures to reduce overburden loads.The potential amplification of ground motion in a tunnel site is well understood,but the effect of the tunnel-TDA layer system on ground surface acceleration remains unclear.In this study,both linear and nonlinear dynamic analyses were performed to evaluate the contributions of a TDA layer to the acceleration amplification at the ground surface.The numerical model was calibrated using recorded data from a shaking table test and validated against the literature results,followed by extensive parametric studies.The mechanical and geometrical parameters investigated for the TDA layer included damping ratio,density,Young’s modulus,width,thickness,and depth.The predominant frequency and intensity level of input motions were also investigated.This study showed that the presence of the TDA layer provided an additional acceleration amplification effect.The amplification was more pronounced in areas above the tunnel,particularly for the wider and shallower TDA layer subjected to high frequency and low intensity input motions. 展开更多
关键词 tire-derived aggregate amplification effect tunnel site acceleration numerical model
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Branched-chain amino acids in muscle growth:mechanisms,physiological functions,and applications
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作者 Shuyong Xu Guangyong Zhao +2 位作者 Mark D.Hanigan Gonzalo Cantalapiedra-Hijar Mengmeng Li 《Journal of Animal Science and Biotechnology》 2026年第1期81-100,共20页
Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate s... Skeletal muscle accounts for approximately 40%of body mass and 50%–75%of whole-body protein,playing a central role in meat production and quality.Efficient protein synthesis in skeletal muscle relies on an adequate supply of nutrient substrates and a balanced amino acid profile.Branched-chain amino acids(BCAA),including leucine(Leu),isoleucine(Ile),and valine(Val),are the most abundant essential amino acids in skeletal muscle and contribute to both protein synthesis and oxidative energy production.Additionally,BCAA function as signaling molecules that regulate gene expression and protein phosphorylation cascades,which significantly influence physiological processes,such as protein synthesis and degradation,glucose and lipid metabolism,and cell apoptosis and autophagy.These processes are primarily mediated through the PI3K/AKT/AMPK/mTOR signaling pathways.This review summarizes BCAA transporters and catabolic metabolism,their role as signaling molecules in regulating protein metabolism and glucose and lipid equilibrium,and applications in animal production.These findings offer both theoretical insights and practical guidelines for the precise regulation of feed efficiency and production performance through tailored dietary BCAA supplementations. 展开更多
关键词 Animal nutrition Branched-chain amino acid Metabolic regulation Signaling mechanism Skeletal muscle
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Heat flow as a catalyst for radiogenic helium release in the East Africa Rift System
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作者 Ernest Mulaya Jon Gluyas +2 位作者 Ken McCaff rey David Byrne Chris Ballentine 《Acta Geochimica》 2026年第1期65-85,共21页
The Rukwa Rift section of the East Africa Rift System presents a type setting for radiogenic helium accumulation in a petroleum free basin.As a prerequisite for accumulation,a considerable high heat flow anomaly is re... The Rukwa Rift section of the East Africa Rift System presents a type setting for radiogenic helium accumulation in a petroleum free basin.As a prerequisite for accumulation,a considerable high heat flow anomaly is required from tectonothermal events to drive the release and circulation of radiogenic helium in the continental crust.Here we apply statistical analysis on geochemical data observed in thermal springs and recorded heat flow to account for crustal helium mass balance for each tectonothermal event in the region.Our results demonstrate anomalously high heat flow~64-99 mW/m^(2) with a consistent trend of helium isotopic ratio and fluid chemistry in the Rukwa Rift.Mass balance calculation show that the whole crustal volume underlying the East Africa Helium Pool(EAHP)has a capability of producing radiogenic helium of about 9.9×10^(6) mol/yr(22×10^(-6) mol 4He/m^(2) yr)while the total radiogenic helium flux ranges between~2.39×10^(6) mol/yr and~2.68×10^(9) mol/yr.The Tanzania Craton contributes largely to radiogenic helium releasing up to 50% of the total capacity in the region.The total ^(4)He emission in the Rukwa Rift Basin is about 4.45×10^(5)-5.01×10^(8) mol/yr which is thus equivalent to 19%-21% of the total production capacity in the region.These results imply that the helium accumulation in the EAHP would have started as early as Paleoproterozoic(2.349 Ga).These results provide a qualitative and quantitative insight to assess both helium and geothermal potentiality in the region. 展开更多
关键词 Radiogenic helium Rukwa Rift Heat flow Helium potential Helium concentration
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Scaling of thin wire cylindrical compression with material,diameter,and laser energy after 100 fs Joule surface heating
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作者 L.Yang M.-L.Herbert +32 位作者 C.Baehtz V.Bouffetier E.Brambrink T.Dornheim N.Fefeu T.Gawne S.Goede J.Hagemann H.Hoppner L.G.Huang O.Humphries T.Kluge D.Kraus J.Lütgert J.-P.Naedler M.Nakatsutsumi A.Pelka T.R.Preston C.B.Qu S.V.Rahul L.Randolph R.Redmer M.Rehwald J.J.Santos M.Smíd U.Schramm J.-P.Schwinkendorf M.Vescovi U.Zastrau K.Zeil A.Laso Garcia T.Toncian T.E.Cowan 《Matter and Radiation at Extremes》 2026年第1期68-80,共13页
We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based im... We present the first systematic experimental validation of return-current-driven cylindrical implosion scaling in micrometer-sized Cu and Al wires irradiated by J-class femtosecond laser pulses.Employing XFEL-based imaging with sub-micrometer spatial and femtosecond temporal resolution,supported by hydrodynamic and particle-in-cell simulations,we reveal how return current density depends precisely on wire diameter,material properties,and incident laser energy.We identify deviations from simple theoretical predictions due to geometrically influenced electron escape dynamics.These results refine and confirm the scaling laws essential for predictive modeling in high-energy-density physics and inertial fusion research. 展开更多
关键词 cylindrical implosion scaling laser energy thin wire cylindrical compression MATERIAL cu al wires DIAMETER systematic experimental validation
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Advancing living Bacillus spore identification:Multi-head self-attention mechanism-enabled deep learning combined with single-cell Raman spectroscopy
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作者 Mengjiao Xue Fusheng Du +5 位作者 Lin He Junhui Hu Yuanpeng Li Yuan Lu Shuwen Zeng Yufeng Yuan 《Journal of Innovative Optical Health Sciences》 2026年第1期139-155,共17页
Many spore-forming Bacillus species can cause serious human diseases,because of accidental Bacillusspore infection.Thus,developing an identification strategy with both high sensitivity and specificity is greatly in de... Many spore-forming Bacillus species can cause serious human diseases,because of accidental Bacillusspore infection.Thus,developing an identification strategy with both high sensitivity and specificity is greatly in demand.In this work,we proposed a novel approach named multi-head self-attention mechanism-guided neural network Raman platform to identify living Bacillus spores within a single-cell resolution.The multi-head self-attention mechanism-guided neural network Raman platform was created by combining single-cell Raman spectroscopy,convolutional neural network(CNN),and multi-head self-attention mechanism.To address the limited size of the original spectra dataset,Gaussian noise-based spectra augmentation was employed to increase the number of single-cell Raman spectra datasets for CNN training.Owing to the assistance of both spectra augmentation and multi-head self-attention mechanism,the obtained prediction accuracy of five Bacillus spore species was further improved from 92.29±0.82%to 99.43±0.15%.To figure out the spectra differences covered by the multi-head self-attention mechanism-guided CNN,the relative classification weight from typical Raman bands was visualized via multi-head self-attention mechanism curve.In the process of spectra augmentation from 0 to 1000,the distribution of relative classification weight varied from a discrete state to a more concentrated phase.More importantly,these highlighted four Raman bands(1017,1449,1576,and 1660 cm^(-1))were assigned large weights,showing that the spectra differences in the Raman bands produced the largest contribution to prediction accuracy.It can be foreseen that,our proposed sorting platform has great potential in accurately identifying Bacillus and its related genera species at a single-cell level. 展开更多
关键词 Multi-head self-attention mechanism CNN single-cell Raman spectroscopy spectra augmentation advanced Bacillus spore identification
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Balancing energy efficiency and avian conservation:divergent nest-site selection responses of Barn Swallows and Red-rumped Swallows to attached sunspaces in cold rural landscapes
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作者 Zheng Han Kaiyan Li +8 位作者 Xiaoxiao Wang Xi Yang Piotr Tryjanowski Frederic Jiguet Letao Huang Houjun Wang Jingshu Zhang Ziqi liu Haitao Wang 《Avian Research》 2026年第1期108-115,共8页
Human-modified landscapes serve as ecological filters,determining species distributions and persistence.Energy-efficient technologies,while crucial for climate change mitigation,represent novel filters whose impacts o... Human-modified landscapes serve as ecological filters,determining species distributions and persistence.Energy-efficient technologies,while crucial for climate change mitigation,represent novel filters whose impacts on synanthropic biodiversity are poorly understood.We investigated how attached sunspaces,a widely adopted energy-saving technology in rural China,filter the distribution of two ecologically important aerial insectivores,the Barn Swallow(Hirundo rustica)and Red-rumped Swallow(Cecropis daurica).We surveyed 106 villages during the 2024 and 2025 breeding seasons and recorded a total of 2323 nests(612 Barn Swallow,1711 Red-rumped Swallow).Using Generalized Linear Models,we assessed their responses to building characteristics,landscape composition and the prevalence of sunspaces.Barn Swallow nests preferred perches at the base and single attachment faces,while Red-rumped Swallow nests favored multiple attachment faces and avoided long shelters.The proportion of buildings with sunspaces acted as a strong positive filter for Barn Swallow nest abundance(+24%)but as a significant negative filter for Red-rumped Swallow(-51%).Other landscape variables(e.g.,human population density,NDVI,Human Footprint Index)were not significant.This study demonstrates that specific architectural innovations can act as powerful ecological filters,leading to divergent distributional outcomes for sympatric species reliant on anthropogenic structures.Our findings reveal a critical trade-off in sustainable development:energy efficiency gains may inadvertently reduce habitat suitability for certain species.To reconcile climate and biodiversity goals in rural landscapes,we advocate integrating species-specific habitat requirements into building design.We propose actionable modifications to sunspaces to support swallows without compromising energy savings.These principles provide a template for mitigating the distributional impacts of green infrastructure globally. 展开更多
关键词 Barn Swallows Energy efficiency Multi-scale analysis Nest-site selection Red-rumped Swallows Rural landscape Sunspace
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Blood serum from individuals with Alzheimer’s disease alters microglial phagocytosis in vitro
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作者 Barbara Altendorfer Rodolphe Poupardin +21 位作者 Sophie Lefèvre-Arbogast Claudine Manach Dorrain Y.Low Mireia Urpi-Sarda Cristina Andres-Lacueva Raúl González-Domínguez Thomas K.Felder Julia Tevini Marco Zattoni Andreas Koller Reinhold Schmidt Paul J.Lucassen Silvie R.Ruigrok Chiara de Lucia Andrea Du Preez Catherine Helmer Jeanne Neuffer Cécile Proust-Lima Aniko Korosi Cécilia Samieri Sandrine Thuret Ludwig Aigner 《Neural Regeneration Research》 2026年第6期2433-2439,共7页
In Alzheimer’s disease,microglial phagocytosis is engaged in the pathogenesis as it clears abnormal protein accumulations,debris,and apoptotic cells in the early stages of Alzheimer’s disease,but fuels neuroinflamma... In Alzheimer’s disease,microglial phagocytosis is engaged in the pathogenesis as it clears abnormal protein accumulations,debris,and apoptotic cells in the early stages of Alzheimer’s disease,but fuels neuroinflammation and accelerates disease progression in later stages.In vivo parabiosis experiments in aged animals have demonstrated that blood-born factors modulate synaptic plasticity,neurogenesis,and microglial responses.We hypothesize that peripheral factors can modulate microglial function and thereby possibly influence Alzheimer’s disease pathology.The objective of this study is to investigate the effects of Alzheimer’s disease serum on microglial phagocytosis.Here,we use an immortalized human microglial cell line in an in vitro parabiosis assay to investigate the impact of the serum from individuals diagnosed with Alzheimer’s disease(n=30)and age-matched controls(n=30)(PRODEM study)on microglial phagocytosis.Exposure to Alzheimer’s disease serum increased microglial phagocytic uptake of pH-sensitive fluorescent particles and downregulated expression of the lysosomal master regulator transcription factor EB(TFEB)and of ATPase H^(+)transporting lysosomal V1 subunit B2(ATP6V1B2),a component of the vacuolar ATPase.To identify serum components that may relate to changes in phagocytosis,serum samples of the Three-City Study(3C Study)were used.In the 3C Study,blood samples were collected up to 12 years before the onset of cognitive decline or dementia and their serum metabolome is well-defined.Microglia exposed to the serum of future Alzheimer’s disease patients from the 3C Study displayed an increased phagocytic uptake compared with the serum of matched controls,depending on the presence of the apolipoprotein Eε4 allele in the Alzheimer’s disease patients.Furthermore,microglial phagocytosis correlated inversely with serum levels of the omega-3 fatty acid eicosapentaenoic acid.We confirmed this inverse correlation between eicosapentaenoic acid and phagocytosis in the serum samples of the PRODEM cohort.In addition,in vitro testing of eicosapentaenoic acid on microglial phagocytosis showed a concentration-dependent decrease in phagocytic uptake.In conclusion,following incubation with Alzheimer’s disease blood serum,we observed increased microglial phagocytic uptake and the downregulation of TFEB and ATP6V1B2,possibly indicating lysosomal dysfunction.Furthermore,microglial phagocytosis was inversely correlated with serum eicosapentaenoic acid levels,suggesting an important role for dietary eicosapentaenoic acid in microglial function. 展开更多
关键词 Alzheimer’s disease blood serum eicosapentaenoic acid in vitro parabiosis METABOLOME microglia omega-3 fatty acids PHAGOCYTOSIS
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基于改进YOLOv5s的矿井下安全帽佩戴检测算法 被引量:9
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作者 王媛彬 韦思雄 +2 位作者 吴华英 段誉 刘萌 《煤炭科学技术》 北大核心 2025年第S1期366-377,共12页
针对矿井下复杂环境所导致的人员安全帽检测算法精确度低、漏检率高等问题,提出一种基于YOLOv5s改进的矿井下安全帽检测算法。卷积神经网络在提取特征时由于计算机制容易导致图像全局上下文信息丢失,造成井下小目标安全帽的检测效果欠... 针对矿井下复杂环境所导致的人员安全帽检测算法精确度低、漏检率高等问题,提出一种基于YOLOv5s改进的矿井下安全帽检测算法。卷积神经网络在提取特征时由于计算机制容易导致图像全局上下文信息丢失,造成井下小目标安全帽的检测效果欠佳。为此,采用注意力机制CBAM与YOLOv5s进行融合,增强目标区域的特征图,弱化背景信息,从而帮助算法更好地定位小目标安全帽。同时,在YOLOv5s原有3个输出层的基础上新增了1个P2小目标检测层,增加了模型的多尺度感受野,可以同时捕获全局和局部上下文信息,提升了算法在复杂场景中针对小目标的检测能力。此外,采用EIoU损失替换原有的CIoU损失函数,解决预测框宽高比模糊的问题,保证回归框的精度,同时加快网络的收敛速度。通过将YOLOv5s主干网络中的普通卷积Conv替换为ShuffleNetV2,大幅减少模型参数量,提高了模型的识别速度。最后,将改进后的算法与YOLOv5s、SSD、FasterRCNN以及YOLOv7算法进行对比分析,实验结果表明:将改进后的算法应用于矿井下人员安全帽检测中,相比于原YOLOv5s,准确率提升了2.9%,召回率提升了2.42%,参数量减少了7.6%,最终在矿井下安全帽检测的平均精度mAP@.5达到了87.5%。 展开更多
关键词 安全帽检测 YOLOv5s 矿井 CBAM ShuffleNetV2
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法向扰动下裂隙砂岩的剪切力学性质与细观演化特征
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作者 张洁 冯国瑞 +5 位作者 郭军 文晓泽 冯文明 张旭 张亮 DIAS Daniel 《采矿与岩层控制工程学报》 北大核心 2025年第2期178-193,共16页
为探究裂隙岩体在扰动作用下的剪切力学行为和细观演化特征,开展了恒定作用下裂隙砂岩的直剪试验,采用PFC^(2D)建立了不同裂隙角度离散元模型,分析了法向恒定和扰动作用下试样的剪切强度和破坏特征;基于剪切过程中细观演化规律,揭示了... 为探究裂隙岩体在扰动作用下的剪切力学行为和细观演化特征,开展了恒定作用下裂隙砂岩的直剪试验,采用PFC^(2D)建立了不同裂隙角度离散元模型,分析了法向恒定和扰动作用下试样的剪切强度和破坏特征;基于剪切过程中细观演化规律,揭示了扰动作用下裂隙砂岩的裂纹扩展规律和能量耗散机理。研究结果表明:①预制裂隙使岩石剪切强度显著降低,两种加载模式下不同裂隙角度的剪切强度降幅分别为9.79%~20.28%和11.12%~16.78%;随着裂隙角度增加,应力–应变曲线斜率降低,剪切强度和峰值位移呈现出先增大后减小的趋势,具有明显的角度效应,剪切强度与裂隙角度成三次函数关系;法向扰动削弱了角度效应的影响,使岩石抵抗剪切变形的能力减弱,破坏提前。②在剪切过程中,岩石内部力链呈现出与荷载方向一致的演化趋势,微裂纹主要从试样两端和预制裂隙两端萌生和发育;微裂纹倾角主要分布在20°~80°,破坏后剪切裂纹占比为78%~81%,扰动作用使该过程中产生的各类裂纹增多,起裂位移减小,剪切裂纹占比增大。③AE振铃计数的发展可分为平静期、缓增期、爆发期和稳定期,扰动作用下“平静期”较短,且在“缓增期”呈现出阶梯性增长趋势。④扰动作用下的剪切试验,试样失效点的总能量较低;直至试样破坏,大部分输入能都以弹性应变能的形式储存在试样中,且在扰动作用下的弹性能显著低于恒定作用下的,降幅达到9.87%~13.94%;扰动使试样储能能力降低,耗散能增加,更容易产生裂纹从而破坏。 展开更多
关键词 裂隙岩体 法向扰动 剪切特性 细观演化 能量耗散
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阿尔金断裂带东西两端构造转换与扩展过程:从三联点谈起 被引量:1
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作者 衣可心 Marc Jolivet 郭召杰 《地质力学学报》 北大核心 2025年第1期24-38,共15页
阿尔金断裂带作为青藏高原北缘的关键构造边界,其演化历史和构造转换机制对理解青藏高原的生长极为重要。阿尔金断裂带不同分段的构造环境与演化历程不同,其各自与祁连山造山带和祁曼塔格-东昆仑断裂带的构造转换研究也仍有不足之处。... 阿尔金断裂带作为青藏高原北缘的关键构造边界,其演化历史和构造转换机制对理解青藏高原的生长极为重要。阿尔金断裂带不同分段的构造环境与演化历程不同,其各自与祁连山造山带和祁曼塔格-东昆仑断裂带的构造转换研究也仍有不足之处。三联点分析是板块构造学中的重要分析方法,速度三角形反映了断裂属性,三联点稳定性则从运动学角度揭示了断裂的演化方向和历程。综合地质、地貌与地震资料,系统分析了阿尔金断裂带中段与东西段代表性的肃北与吐拉三联点的构造特征与活动历史;并借助三联点稳定性准则,构建了这2个三联点的演化模型。研究结果表明,野马河-大雪山断裂与祁曼塔格-东昆仑断裂带启动,不稳定三联点形成并向稳定三联点转化,促使阿尔金断裂带“截弯取直”,并在此基础上提出了分段破裂-双向扩展模型。这一结果为理解青藏高原北缘复杂的构造演化历史提供了新的视角。 展开更多
关键词 阿尔金断裂带 青藏高原北缘 三联点 构造转换 祁连山造山带
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基于NSGA-Ⅱ优化的电动汽车热管理系统MPC策略开发及性能
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作者 戴春江 林文野 +4 位作者 李帅旗 陈翔 宋文吉 冯自平 Frédéric KUZNIK 《储能科学与技术》 北大核心 2025年第6期2200-2214,共15页
电动汽车热管理在保障电动汽车的安全性、提高舒适度和降低能耗等方面具有重要意义,而热管理系统的核心是优良的控制策略。本工作回顾了现有的电动汽车热管理系统控制策略的优点与不足,提出并评价了一种基于NSGA-Ⅱ算法优化的模型预测控... 电动汽车热管理在保障电动汽车的安全性、提高舒适度和降低能耗等方面具有重要意义,而热管理系统的核心是优良的控制策略。本工作回顾了现有的电动汽车热管理系统控制策略的优点与不足,提出并评价了一种基于NSGA-Ⅱ算法优化的模型预测控制(MPC)策略并用于电动汽车的热管理。首先建立了电动汽车热管理系统的仿真模型;随后通过融合MPC策略和NSGA-Ⅱ多目标优化提出了可以实现多目标控制的电动汽车热管理策略;最后通过比较多个工况下不同控制策略对汽车热管理系统性能的影响,以验证所提出的基于NSGA-Ⅱ优化的MPC策略的有效性。研究结果发现,在不同工况下,所提出的MPC策略均可有效控制乘员舱温度和电池温度,减小乘员舱温度和电池温度的波动幅度,削减汽车行驶工况剧烈变化对电池温度的影响;同时,MPC策略可有效降低热管理系统能耗,相对于开关控制策略和PID控制策略可实现可观的节能率,分别达到4%~15%和1%~6%。 展开更多
关键词 热管理 控制优化 MPC NSGA-Ⅱ 电动汽车
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Decoding the nexus:branched-chain amino acids and their connection with sleep,circadian rhythms,and cardiometabolic health 被引量:2
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作者 Hui Li Laurent Seugnet 《Neural Regeneration Research》 SCIE CAS 2025年第5期1350-1363,共14页
The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given th... The sleep-wake cycle stands as an integrative process essential for sustaining optimal brain function and,either directly or indirectly,overall body health,encompassing metabolic and cardiovascular well-being.Given the heightened metabolic activity of the brain,there exists a considerable demand for nutrients in comparison to other organs.Among these,the branched-chain amino acids,comprising leucine,isoleucine,and valine,display distinctive significance,from their contribution to protein structure to their involvement in overall metabolism,especially in cerebral processes.Among the first amino acids that are released into circulation post-food intake,branched-chain amino acids assume a pivotal role in the regulation of protein synthesis,modulating insulin secretion and the amino acid sensing pathway of target of rapamycin.Branched-chain amino acids are key players in influencing the brain's uptake of monoamine precursors,competing for a shared transporter.Beyond their involvement in protein synthesis,these amino acids contribute to the metabolic cycles ofγ-aminobutyric acid and glutamate,as well as energy metabolism.Notably,they impact GABAergic neurons and the excitation/inhibition balance.The rhythmicity of branchedchain amino acids in plasma concentrations,observed over a 24-hour cycle and conserved in rodent models,is under circadian clock control.The mechanisms underlying those rhythms and the physiological consequences of their disruption are not fully understood.Disturbed sleep,obesity,diabetes,and cardiovascular diseases can elevate branched-chain amino acid concentrations or modify their oscillatory dynamics.The mechanisms driving these effects are currently the focal point of ongoing research efforts,since normalizing branched-chain amino acid levels has the ability to alleviate the severity of these pathologies.In this context,the Drosophila model,though underutilized,holds promise in shedding new light on these mechanisms.Initial findings indicate its potential to introduce novel concepts,particularly in elucidating the intricate connections between the circadian clock,sleep/wake,and metabolism.Consequently,the use and transport of branched-chain amino acids emerge as critical components and orchestrators in the web of interactions across multiple organs throughout the sleep/wake cycle.They could represent one of the so far elusive mechanisms connecting sleep patterns to metabolic and cardiovascular health,paving the way for potential therapeutic interventions. 展开更多
关键词 branched-chain amino acids cardiovascular health circadian clock DROSOPHILA INSULIN metabolism SLEEP γ-aminobutyric acid
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Telencephalic stab wound injury induces regenerative angiogenesis and neurogenesis in zebrafish:unveiling the role of vascular endothelial growth factor signaling and microglia 被引量:1
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作者 Danielle Fernezelian Philippe Rondeau +1 位作者 Laura Gence Nicolas Diotel 《Neural Regeneration Research》 SCIE CAS 2025年第10期2938-2954,共17页
After brain damage,regenerative angiogenesis and neurogenesis have been shown to occur simultaneously in mammals,suggesting a close link between these processes.However,the mechanisms by which these processes interact... After brain damage,regenerative angiogenesis and neurogenesis have been shown to occur simultaneously in mammals,suggesting a close link between these processes.However,the mechanisms by which these processes interact are not well understood.In this work,we aimed to study the correlation between angiogenesis and neurogenesis after a telencephalic stab wound injury.To this end,we used zebrafish as a relevant model of neuroplasticity and brain repair mechanisms.First,using the Tg(fli1:EGFP×mpeg1.1:mCherry)zebrafish line,which enables visualization of blood vessels and microglia respectively,we analyzed regenerative angiogenesis from 1 to 21 days post-lesion.In parallel,we monitored brain cell proliferation in neurogenic niches localized in the ventricular zone by using immunohistochemistry.We found that after brain damage,the blood vessel area and width as well as expression of the fli1 transgene and vascular endothelial growth factor(vegfaa and vegfbb)were increased.At the same time,neural stem cell proliferation was also increased,peaking between 3 and 5 days post-lesion in a manner similar to angiogenesis,along with the recruitment of microglia.Then,through pharmacological manipulation by injecting an anti-angiogenic drug(Tivozanib)or Vegf at the lesion site,we demonstrated that blocking or activating Vegf signaling modulated both angiogenic and neurogenic processes,as well as microglial recruitment.Finally,we showed that inhibition of microglia by clodronate-containing liposome injection or dexamethasone treatment impairs regenerative neurogenesis,as previously described,as well as injury-induced angiogenesis.In conclusion,we have described regenerative angiogenesis in zebrafish for the first time and have highlighted the role of inflammation in this process.In addition,we have shown that both angiogenesis and neurogenesis are involved in brain repair and that microglia and inflammation-dependent mechanisms activated by Vegf signaling are important contributors to these processes.This study paves the way for a better understanding of the effect of Vegf on microglia and for studies aimed at promoting angiogenesis to improve brain plasticity after brain injury. 展开更多
关键词 ANGIOGENESIS cerebral damage inflammation NEUROGENESIS stab wound TELENCEPHALON vascular endothelial growth factor ZEBRAFISH
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