Medical Engineering & Physics最新文献

{"title":"Investigation of critical buckling load enhancements via ultrasonic vibration assisted implantation of microwire-based brain electrodes.","authors":"Dongyang Yi, Njinang Kwankam, Lei Chen","doi":"10.1088/1873-4030/ae691d","DOIUrl":"https://doi.org/10.1088/1873-4030/ae691d","url":null,"abstract":"<p><strong>Objective: </strong>Ultrasonic vibration assisted insertion has shown promising results on large and rigid brain electrodes but had limited benefits towards small and flexible electrodes like thin microwires. This study aims to quantitatively investigate the vibration's impact on the electrode's critical buckling load and optimal vibration parameter choice for effective vibration transmission to microwire tips.</p><p><strong>Approach: </strong>A custom ultrasonic insertion platform was developed to deliver controlled longitudinal vibrations to tungsten microwires under a fixedpinned boundary condition. Experiments varied four factors: wire diameter (50.8 -101.6 µm), preload mass (0 -112.35 g), vibration frequency (33 -42 kHz), and drive voltage amplitude (106 and 212 VRMS). Vibration characteristics were quantified using Photonic Doppler Velocimetry, and buckling outcomes were assessed by enhancement percentage of the critical buckling load against static theoretical values. Analysis of variance was conducted to investigate vibration parameters' impacts on the critical buckling load enhancement.</p><p><strong>Main results: </strong>Ultrasonic vibration assistance not only reduces membrane rupture force but also significantly increased the effective critical buckling load, with enhancements exceeding 60% in some cases. ANOVA revealed that all four factors-frequency, voltage, preload mass, and wire diameter-had statistically significant effects (p < 0.05). Higher vibration frequency (38-42 kHz) and smaller wire size (50.8 µm) generally yields higher critical buckling load enhancement while an intermediate level of pre-load mass (54.51 g) would be beneficial for high efficiency vibration transduction to the tip of small lightweight wire electrodes. Vibration amplitude and corresponding drive voltage should be carefully chosen to mitigate imperfections during the acceleration and deceleration periods.</p><p><strong>Significance: </strong>This study, for the first time, quantitatively demonstrates the enhancement of electrode critical buckling load under ultrasonic vibration assistance. The experimental investigations provided valuable insights and guidelines for vibration assistance parameter selection to ease the brain electrode implantation process.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147845324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of acoustic systems for ultrasound attenuation measurement in polydimethylsiloxane (PDMS).","authors":"Mathis Pierre Claude Martin, Pascal Dargent, Wladimir Urbach, Nicolas Taulier, Alireza Ashofteh","doi":"10.1088/1873-4030/ae691f","DOIUrl":"https://doi.org/10.1088/1873-4030/ae691f","url":null,"abstract":"<p><p>Ultrasound absorption by polydimethylsiloxane (PDMS) can have a significant impact on the acoustic radiation force needed for stimulation of cells in organ-on-a-chip. Hence, finding the PDMS attenuation coefficient is the key to determine the fraction of absorbed acoustic energy in microfluidic systems. To measure the attenuation coefficient of PDMS, two methods were compared: a vector network analyzer (VNA) and a pulse transmission method. Ten PDMS samples with thicknesses ranging from 2.5 to 18.5 mm were tested both before and after 24-hour water immersion. The attenuation coefficient of PDMS, commonly used in microfluidics, was determined within a frequency range relevant to human health, i.e. 1-3 MHz. For a representative 5 mm thick microfluidic chip, the fraction of absorbed acoustic energy (E) is estimated to be approximately 21% at 1 MHz and 68% at 3 MHz. This level of absorption is expected to substantially modulate cell stimulation mediated by acoustic radiation forces.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147845309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A multi-parameter performance correlation model to advance the customized design of vascular stents.","authors":"Ankun Xie, Changsheng He, Kellen Mitchell, Weiliang Shi, Sai Ma, Yifei Jin, Danyang Zhao","doi":"10.1088/1873-4030/ae691e","DOIUrl":"https://doi.org/10.1088/1873-4030/ae691e","url":null,"abstract":"<p><p>The clinical performance of vascular stents hinges on a delicate balance between radial support and bending flexibility. Existing theoretical models are further limited by their focus on single materials or specific geometries, offering little guidance for complex hybrid or functionally graded designs. To overcome these limitations, we present a multi-parameter performance-correlation model (PCM) that unifies material properties, topological features, and cross-sectional parameters into a single analytical framework aimed at accelerating stent design. The PCM derives its governing dimensional relationships from analytical mechanics and is calibrated using a comprehensive FEA database encompassing three representative architectures, four materials, and nine cross-sectional configurations. The model accurately predicts stent mechanical responses, and key analysis reveals that strut width contributes to radial stiffness through a cubic scaling law, significantly stronger than the linear dependence on strut thickness. This finding identifies width enhancement as a more effective strategy for improving radial support without substantially compromising flexibility. Case studies further demonstrate that non-uniform stents yield greater luminal gain at lesion sites, while hybrid designs achieve a functional decoupling of support and compliance. Overall, the proposed PCM offers an efficient tool for earlystage concept screening and design optimization of multi-material, functionally graded vascular stents.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147845336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cerebellar neuromodulation synchronized to ankle-assist cycling yields prolonged post-assist dorsiflexion.","authors":"Keisuke Hirata, Hiroki Hanawa, Taku Miyazawa, Keisuke Kubota, Naohiko Kanemura, Kojiro Iizuka","doi":"10.1088/1873-4030/ae6868","DOIUrl":"https://doi.org/10.1088/1873-4030/ae6868","url":null,"abstract":"<p><p>Structured Abstract: Rhythmic lower-limb movements require precise coordination across multiple joints, a process in which the cerebellum is thought to play a critical role. This study investigated whether cerebellar neuromodulation synchronized with mechanical ankle assistance modulates use-dependent motor adaptation during cyclic movement in healthy young adults. A portable ankle-assist ergometer delivered phase-specific dorsiflexion torque during cycling, and participants completed three within-subject conditions: Sham stimulation, synchronized transcranial alternating current stimulation (tACS), and unsynchronized tACS. Ankle dorsiflexion angle and tibialis anterior muscle activity were assessed before, during, and after a 6-min assistance period. Baseline-normalized data were analyzed using linear mixed-effects models across assist and post-assist phases. Synchronized cerebellar stimulation significantly modulated the overall magnitude of the dorsiflexion aftereffect, whereas unsynchronized stimulation did not. In contrast, tibialis anterior muscle activity exhibited robust phase-dependent changes but did not differ across stimulation conditions, indicating that the kinematic modulation was not driven by sustained changes in agonist muscle activation. These findings demonstrate that phase-aligned cerebellar neuromodulation biases adaptive motor output during cyclic lower-limb movement, likely by influencing multijoint coordination and predictive control rather than peripheral muscle recruitment. The combination of a compact ankle-assist ergometer with precisely timed, non-invasive cerebellar stimulation provides an accessible platform for probing and biasing motor adaptation, with potential implications for future lower-limb rehabilitation strategies.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147845306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive assessment of pectus excavatum: Analyzing chest wall anatomy, cardiac rotation, and severity classification for enhanced diagnosis and treatment.","authors":"Talia Busquets, S D Lynch, F S Gayzik, Ashley Weaver","doi":"10.1088/1873-4030/ae6666","DOIUrl":"https://doi.org/10.1088/1873-4030/ae6666","url":null,"abstract":"<p><p>Pectus excavatum is the most common congenital chest wall deformity, characterized by a depression of the anterior chest wall which may compromise cardiac function and cause symptoms like exercise intolerance, chest pain, and shortness of breath. While diagnosis is often based on appearance, imaging-based metrics provide objective severity assessment. This study evaluated associations between pectus excavatum severity indices and cardiac rotation angle in 37 adolescents generated two sex-specific anatomical models of severe cases for future diagnostic and treatment planning. Chest computed tomography (CT) scans of 30 male and 7 female pectus excavatum patients aged 12-16 years were analyzed to measure the Haller index, Correction index, and cardiac rotation angle. Severity by Haller index was classified as mild (2.0-3.2cm, n=15), moderate (3.2-3.5cm, n=7), or severe (>3.5cm, n=15). Cardiac rotation angle increased with severity (p=0.001): mild (37.6±13.1°), moderate (44.8±13.6°), and severe (51±13.2°). Cardiac rotation angle was positively associated with the Haller index (R²=0.24, p=0.002), but not the Correction index (R²=0.01, p=0.55). CT scans of a representative male and female were segmented to generate 3D models of thoracic and abdominal structures. These measurements and models may inform diagnostic criteria, treatment planning, and personalized device development for adolescents with pectus excavatum.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147787402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of pressure relief in gradient lattice orthotic insoles based on plantar pressure-rod diameter mapping.","authors":"Lihong Wang, Jiali Zhao, Yuan Liu","doi":"10.1088/1873-4030/ae6593","DOIUrl":"https://doi.org/10.1088/1873-4030/ae6593","url":null,"abstract":"<p><strong>Objective: </strong>Traditional orthotic insoles exhibit limited mechanical adaptability, making them insufficient for addressing individualized foot correction requirements. Although gradient lattice structures show promise in enhancing mechanical compatibility, their regional modulus regulation lacks a reliable theoretical foundation, thereby significantly hindering performance optimization and clinical translation of such insoles. This study aims to optimize the structural design of orthotic insoles and systematically evaluate their pressure-relieving performance through computational modeling and comparative analysis.</p><p><strong>Approach: </strong>First, a quantitative relationship between elastic modulus and relative density is established through mechanical analysis of lattice unit structures. Subsequently, this relationship is employed to construct a foot pressure-to-rod diameter mapping model, enabling precise regional modulus customization in the insole by modulating lattice unit density. Finally, finite element simulations are conducted to systematically compare the pressure-relief performance of six distinct structural insole designs and evaluate their effectiveness in optimizing plantar pressure distribution.</p><p><strong>Main results: </strong>The results show that the full-contact continuous positive gradient octst-S lattice orthopedic insoles designed using the proposed method have a 61.09% reduction in peak plantar pressure compared to flat insoles. These improvements lead to a more uniform pressure distribution and effective mitigation of local stress concentration.</p><p><strong>Significance: </strong>This study establishes a quantitative foundation for modulus regulation in gradient lattice orthotic insoles. The developed mapping relationship offers a scalable design strategy and can be readily applied to other functional or medical assistive devices requiring regionally tailored mechanical properties.&#xD;Keywords: Gradient lattice；Modulus regulation；Mapping model for sole pressure-rod diameter.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147787426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of body mass index on heel pad mechanics: loading and unloading dynamics.","authors":"Tharani Kumaran, Monisha Gowri Srinivasan, Mirza Khalid Baig, Thirugnanam Arunachalam","doi":"10.1088/1873-4030/ae5d4b","DOIUrl":"10.1088/1873-4030/ae5d4b","url":null,"abstract":"<p><p>Plantar heel pain (PHP) is the most predominant foot pathological condition persisting among people with obesity. Conventional techniques measure the heel pad's (HPs) thickness, stiffness, and elasticity by subjecting a known force under static conditions. However, it falls short of assessing the HP under natural physiological loading conditions. Therefore, the present study investigates the biomechanical characteristics of the HP during dynamic plantarflexion movement (body weight unloading and loading) using a 3D motion capture system and a multiaxial force plate. Participants were selected and divided into three categories based on body mass index (BMI): healthy weight (HW), overweight (OW), and obese (OB). Each category consisted of thirty male and thirty female participants. The retroreflective markers were placed on the HP, and participants were instructed to perform the plantarflexion movement on the force plate. The biomechanical output parameters, such as HP deformation and compliance, were calculated for different phases of plantarflexion movement along the vertical and horizontal directions. Statistical analysis was performed at a 95% confidence level. The study revealed that male and female participants in the OB category exhibited less HP deformation than those in the HW and OW categories. Male and female participants in the HW category showed higher HP compliance than those in the OB category. The magnitude of HP compliance was higher in the vertical direction than in the horizontal direction. HP stiffness increases with higher BMI (OB > OW > HW) and leads to PHP. The study revealed that males have lower HP compliance and deformation than females. The findings provide a better understanding of HP characteristics across different weight groups, which could be used to develop customized soles that absorb shock during dynamic activity and reduce heel pain among the population with obesity.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147646979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Immobilization and comfort assessment in customized 3D-printed cervical orthosis.","authors":"Yi-Hsiu Wu, Yu-Ching Hsiao, Jing-Jing Fang, Cheng-Li Lin, Ruey-Mo Lin","doi":"10.1088/1873-4030/ae5965","DOIUrl":"https://doi.org/10.1088/1873-4030/ae5965","url":null,"abstract":"<p><p>Customized 3D-printed cervical orthoses usually offer better fit and support. However, clinical evidence regarding the effectiveness of immobilization and comfort remains limited. This study aims to compare the effectiveness of custom-made cervical orthoses with that of commercially available orthoses in preventing pressure ulcers (PUs), improving immobilization, and providing comfort and ease of use. We measured the risk of PUs associated with six neck postures to assess comfort and immobilization when participants wore their orthosis. The customized cervical orthosis provided significantly greater immobilization than the Aspen Vista collar across all six neck postures (<i>p</i>< 0.05). No significant differences in comfort and user preference were observed between the two orthoses. The customized cervical orthosis offers superior immobilization compared to the Aspen Vista collar; however, it may increase pressure on the mastoid processes. While comfort is comparable to commercial options, customized orthosis improvements are needed to reduce pressure without sacrificing immobilization.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":"147 5","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147787396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneous material mapping of micro-finite element models of human trabecular bone cores.","authors":"Mahsa Zojaji, McKinely Van Klei, Heidi-Lynn Ploeg","doi":"10.1088/1873-4030/ae5c09","DOIUrl":"10.1088/1873-4030/ae5c09","url":null,"abstract":"<p><p>Trabecular bone microarchitecture and tissue heterogeneity strongly influence mechanical behaviour, yet homogeneous micro-finite element (<i>µ</i>FE) models neglect tissue heterogeneity, limiting accuracy in local stress-strain predictions. This study evaluated the effects of mesh type (voxel-based linear hexahedral, HEX, vs geometry-based quadratic tetrahedral, TET), mesh resolution, and material property assignment (homogeneous vs heterogeneous) on<i>µ</i>FE predictions of apparent elastic modulus, von Mises stress, and principal strains in human femoral trabecular bone cores. Fourteen cores were micro-computed tomography scanned and meshed into HEX and TET<i>µ</i>FE models at three resolutions, with tissue modulus assigned either homogeneously or heterogeneously using trilinear interpolation from voxel-level density. Models were calibrated to experimentally measured apparent elastic modulus. All models accurately predicted apparent elastic modulus. However, mesh type and resolution substantially influenced local mechanical outcomes. Tetrahedral models produced higher local principal strains and von Mises stresses, indicating improved sensitivity to localized strain concentrations, whereas hexahedral models yielded smoother stress-strain distributions with lower peak values but greater computational efficiency. Finer meshes enhanced the resolution of local strain concentrations, while coarser meshes underestimated peak responses. Incorporating tissue heterogeneity increased local principal strains and reduced peak von Mises stresses, although differences from homogeneous models were modest. These findings demonstrate that mesh type has a stronger influence on local mechanical predictions than material heterogeneity when models are calibrated to bulk stiffness. Geometry-based tetrahedral meshes are preferable when accurate estimation of local strain concentrations is required, whereas voxel-based hexahedral meshes provide a computationally efficient alternative for bulk property prediction. This work provides practical guidance for optimizing<i>µ</i>FE modelling strategies in trabecular bone research.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147634916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Abnormality detection in soft tissues: multivariate outlier framework based on multi-mechanical characterization using indentation.","authors":"Mahmood Abdallah Saleh, Calum Anderson, Ciara B Durcan, William N MacPherson, Duncan P Hand, Robert L Reuben, Yuhang Chen","doi":"10.1088/1873-4030/ae55a1","DOIUrl":"10.1088/1873-4030/ae55a1","url":null,"abstract":"<p><p>Fast and accurate detection of abnormalities, such as tumor nodules, in soft tissue is a critical step toward effective cancer diagnosis. Clinical examples include the use of tactile feedback during digital rectal examination for prostate cancer screening and intraoperative tumor localization. However, the absence of robust mechanical characterization and detection methods limits the clinical applicability of these techniques. In this study, we investigate instrumented indentation as a tool for detecting tumor-mimicking nodules embedded within porcine liver tissue models. Multi-mechanical characterization, including hyperelasticity, viscoelasticity, and dynamic indentation, was performed to capture the mechanical response of the tissue at different points across its surface. A multivariate statistical outlier detection approach, based on Mahalanobis distance, was applied to assess the effectiveness of different mechanical metrics in identifying embedded nodules. The results demonstrate that this outlier detection framework reliably identifies stiff nodules within one to two standard deviations, offering a promising, clinically relevant method for soft tissue cancer detection.</p>","PeriodicalId":49836,"journal":{"name":"Medical Engineering & Physics","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147505617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}