Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine最新文献

{"title":"Design and development of a novel media-separated valve for flow-controlled expiration during mechanical ventilation.","authors":"Patryk Dzierzawski, Bernd Flamm, Benedikt Fischer, Hartmut Breger, Martin Huth, Sashko Spassov, Christin Wenzel, Stefan Schumann, Sara Lozano-Zahonero","doi":"10.1177/09544119261467189","DOIUrl":"10.1177/09544119261467189","url":null,"abstract":"<p><p>Mechanical ventilation has become a central therapeutic means in modern medicine. However, mechanical ventilation carries the risk of ventilator-induced lung injury. Our group introduced flow-controlled expiration (FLEX) as an additional approach to effective, lung-protective mechanical ventilation. By gradually reducing the pneumatic resistance, FLEX controls expiratory flow toward a user-set constant target, replacing the exponential flow-time profile of a conventional expiration. Primarily developed to demonstrate the physiological concept, the initial FLEX-system prototype did not provide closed-loop flow regulation and full media separation. These considerations motivated the development of a more advanced system that precisely adjusts pneumatic resistance to achieve rapid closed-loop control of the desired expiratory flow rates. We validated our system through multiple tests using physical lung surrogates. We could effectively control the expiratory flow with two ventilation devices. We thereby demonstrated that the system attenuated high initial expiratory peak flow and guided expiratory flow toward user-selected target values in physical respiratory-system models under a range of physiological and non-physiological conditions. Our system features an innovative valve that enables accurate flow regulation, facilitates easy valve replacement, and ensures complete separation of the respiratory gas space from the ambient environment, thereby enhancing safety and reliability. Moreover, the microcontroller implementation creates a self-contained system, making it well-suited for potential clinical applications.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"847-860"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148423555","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":"An experimental study on the behavior of enamel-dentin in human teeth at low strain rates.","authors":"Mohammad Alirahimi, Majid Jamal-Omidi, Majid Tavakolian","doi":"10.1177/09544119261467603","DOIUrl":"10.1177/09544119261467603","url":null,"abstract":"<p><p>Human teeth function as nature's cutting and grinding tools and represent a remarkable biocomposite. This study investigates the rate-dependent mechanical behavior of the enamel-dentin (ED) complex at low strain rates. High-precision ED specimens were prepared from healthy human premolars and tested under uniaxial compression using a universal testing machine at strain rates ranging from 0.0005 to 2.5 s^-1. The results demonstrated that, with increasing strain rate, the maximum stress and elastic modulus increased by 17.0% and 24.7%, respectively, while the maximum strain decreased by 12.5%. One-way ANOVA with Tukey's HSD post-hoc testing indicated that strain rate had a statistically significant effect on all three mechanical properties (<i>p</i> < 0.01 for each). This rate sensitivity is attributed to the hierarchical structure and complex organic-inorganic composition of the ED biocomposite. Based on the experimental findings, quantitative relationships were proposed to describe the maximum stress, elastic modulus, and maximum strain as functions of strain rate. These results highlight that the mechanical properties of the ED complex are sensitive to strain rate even within the low rate regime. The present findings can contribute to computational simulations of dental structures, the development of restorative materials, and the design of tissue-engineered artificial teeth.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"795-804"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148423571","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":"Practical evaluation of skin temperature sensors in children during three phases: Clinical differences between contact and infrared methods.","authors":"Ibtissam Elghailassi, Nasrul Anuar Abd Razak, Noor Azuan Abu Osman","doi":"10.1177/09544119261465864","DOIUrl":"10.1177/09544119261465864","url":null,"abstract":"<p><p>Selecting skin temperature screening methods is difficult due to the wide variety of measurement techniques and equipment currently available. The hypothesis behind the various skin temperature measurement techniques is that contact methods can change the local skin temperature, whereas non-contact methods are sensitive to environmental elements and require consistent placement. The study aimed to compare contact and non-contact temperature sensors for measuring skin temperature in children's lower limbs. An experimental study was conducted by utilising NTC thermistors and an infrared thermometer. Seventy children were recruited to participate in this study. Measurements were conducted during three separate trials, which spanned three experimental phases: before, during, and after exercise. The study protocol included 5 min of sitting and resting before the exercise, 5 min of standing in runner's pose/single-leg march during the exercise, and 5 min of sitting and resting afterwards. Skin temperature data were collected over 20-min intervals for each test. Descriptive statistics and statistical differences among the three tests are illustrated. In three test trials, across all phases, scatter plots consistently revealed a robust, strong correlation between NCTS and CTS readings. NCTS systematically demonstrated higher mean temperature readings when compared to CTS under all conditions. Across all tests and phases, paired samples t-tests revealed that the mean differences between NCTS and CTS were statistically significant (<i>p</i> < 0.001). The greatest discrepancies and biggest effect sizes were detected in the after-exercise phase, which peaks in Test 3 (<i>M</i>_diff = 2.78°C, ES = 1.46). CTS methods are more reliable and precise for tracking paediatric exercise.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"861-875"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148423577","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":"Assessment of adaptive trabecular bone remodeling around a knee prosthesis stem using the Weinans model.","authors":"Osvaldo Iván Meza-Jr-Hernández, Agustín Vidal-Lesso, Héctor Plascencia-Mora","doi":"10.1177/09544119261462409","DOIUrl":"10.1177/09544119261462409","url":null,"abstract":"<p><p>Adaptive remodeling of trabecular bone surrounding orthopedic implants plays a critical role in maintaining prosthesis stability and preventing aseptic loosening caused by stress shielding and osteolysis. This study presents a numerical model approach combining Finite Element Analysis and Weinans' bone remodeling model to evaluate the initial density adaptation response of peri-prosthetic femoral trabecular bone under the critical loading condition occurring during the toe-off phase of normal gait. A high-fidelity model incorporating cortical and trabecular bone regions was developed to calculate stress distribution and strain energy density within the peri-prosthetic region. The mechanical stimulus field obtained from the Finite Element Model was subsequently used to evaluate localized remodeling activation and density-related adaptation tendencies. The results showed that localized regions near the stem tip exceeded the ultimate compressive strength of trabecular bone (7.18 MPa), suggesting potential osteolytic activity confined to a limited area. In contrast, stress in the cortical bone remained below reported failure thresholds. Regions subjected to elevated mechanical stimulus exhibited increased trabecular bone density and corresponding improvements in predicted mechanical strength, reaching values close to 10 MPa. The simulations also demonstrated that density adaptation reduced local deformation, thereby promoting mechanical stabilization at the prosthesis-bone interface. These findings support the trabecular bone's capacity to adapt mechanically to implant-induced loading conditions and demonstrate the usefulness of the proposed framework for evaluating peri-prosthetic remodeling behavior and implant load-transfer mechanisms.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"757-767"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148353362","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":"Biomechanical effects of structural optimization on the ball-and-socket lumbar artificial disc: A finite element study.","authors":"Jiahao Yan, Linyi Guan, Yongsheng Li, Tianrong Jin, Yanze Chen, Dingding Xiang","doi":"10.1177/09544119261467211","DOIUrl":"10.1177/09544119261467211","url":null,"abstract":"<p><p>Lumbar disc degeneration is a major contributor to low back pain and disability. Lumbar total disc replacement (LTDR) has been introduced as a motion-preserving alternative to spinal fusion, and its biomechanical performance is strongly influenced by prosthesis geometry. This study investigated the effects of two key geometric parameters, curvature radius and radial clearance, on the biomechanical behavior of a ball-and-socket LTDR. Three-dimensional finite element models of the L3-L5 lumbar spine were developed, incorporating prostheses with curvature radii ranging from 7 to 10 mm and radial clearances from 0.1 to 0.3 mm. Segmental range of motion (ROM) and adjacent intervertebral disc biomechanics were evaluated under physiological loading conditions. Increasing curvature radius substantially reduced flexion and lateral bending ROM while producing radius-dependent effects on axial rotation. It also led to elevated annulus fibrosus (AF) von Mises stress across all motion modes. Nucleus pulposus (NP) von Mises stress and strain increased modestly during flexion and lateral bending but decreased during axial rotation. Total deformation of both NP and AF decreased progressively. In contrast, increasing radial clearance moderately enhanced flexion and lateral bending ROM while producing negligible changes in stress and slightly modulating strain and total deformation. These results indicate that prosthesis geometry plays a key role in modulating spinal kinematics and adjacent segment loading following lumbar total disc replacement. Curvature radius exerts a stronger influence than radial clearance, which mainly serves as a secondary parameter for fine-tuning segmental motion.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"737-756"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148536405","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":"Investigation on mechanical, in vitro corrosion, and biocompatibility behaviour of ZK61-10HA-2.5ES hybrid bio-composite for orthopaedic implant applications.","authors":"Harshit Kumar, Shashi Bhushan Prasad, Ashish Das","doi":"10.1177/09544119261463379","DOIUrl":"10.1177/09544119261463379","url":null,"abstract":"<p><p>Biodegradable implants are crucial for orthopaedic applications, as they eliminate the necessity for a secondary surgical procedure. This investigation adopts composite methodology by reinforcing ZK61 with hydroxyapatite (HA) and eggshell (ES) to fabricate Mg-based metal matrix composite using friction stir processing (FSP). The impact of introducing 10 wt% HA as a bioactive ceramic and 2.5 wt% ES as a green, low-cost reinforcement via FSP on mechanical performance, in vitro corrosion behaviour, and biocompatibility is reported. The microhardness and ultimate compressive strength of the ZK61-10HA-2.5ES composite (74.6 HV, 356 MPa) showed a ∼24% increase in microhardness and a ∼28% increase in UCS compared to ZK61 alloy (60.1 HV, 278 MPa). The corrosion rate of ZK61-10HA-2.5ES composite was assessed using electrochemical measurements and found a lower corrosion rate (1.05 mm/year) compared to ZK61 alloy (3.63 mm/year), which aligned with the results obtained from immersion. After 1 and 3 days of incubation, the MTT assay revealed that the ZK61-10HA-2.5ES composite exhibited grade 0 non-cytotoxic response to MG-63 cells, indicating its promising potential for orthopaedic applications.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"768-781"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520826","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":"Robot-assisted rehabilitation: Collaborating a smart avatar with an AAN controller.","authors":"Tanishka Goyal, Fahad Hussain, Prashant K Jamwal, Shahid Hussain","doi":"10.1177/09544119261467479","DOIUrl":"10.1177/09544119261467479","url":null,"abstract":"<p><p>Despite advances in robot-assisted rehabilitation, existing control strategies often lack real-time personalization to account for subject-specific physiological capabilities, limiting the effectiveness of assist-as-needed interventions. Moreover, there is a further need to account for the patient's physiological functional capacity (PFC) in the design of such assistive technology. Here, an attempt has been made to create an Assist-as-Needed (AAN) Controller that works in collaboration with a Smart Avatar. The Smart Avatar mimics the patient's capabilities by learning in real-time and informing the controller. To efficiently predict the subject's level of involvement, a Reinforcement Learning (RL) based Inverse Dynamics model has been designed. Additionally, the controller for the Avatar has been appended with an Energy Map for modifying the reference trajectories and making the system energy efficient. The human torque estimated by the Smart Avatar assists the Assist-as-Needed (AAN) controller in providing the optimum robot torque to guide the subject's wrist along the modified trajectories. The developed algorithm was validated on five healthy participants. The system achieved trajectory tracking errors in the range of 0.01-0.04 rad across wrist motions. Subject- and axis-dependent differences in interaction torque were examined using descriptive statistics and torque profiles, supporting the feasibility of adaptive assistance under the tested conditions.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"820-835"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148437754","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":"Multi-objective optimization of vibration-assisted bone drilling parameters based on CCD and NSGA-II.","authors":"Ying Han, Yanchao Guo, Xianzheng Zhou, Yimiao Chen, Qinhe Zhang","doi":"10.1177/09544119261464324","DOIUrl":"10.1177/09544119261464324","url":null,"abstract":"<p><p>The drilling force, temperature and surface roughness during bone drilling critically determine bone tissue trauma and surgical performance. To address the difficulty of coordinating multiple conflicting indicators through single-objective optimization, this study conducts multi-objective parameters optimization of low-frequency vibration-assisted bone drilling. Central Composite Design (CCD) is employed to establish quadratic regression models for drilling force, drilling temperature and surface roughness with spindle speed, feed rate, voltage (amplitude), and vibration frequency as input variables. Model validity is confirmed via analysis of variance and residual analysis. Taking the simultaneous minimization of the three machining responses as the objective, the genetic algorithm (NSGA-II) is applied to acquire Pareto optimal solutions. The optimal parameter combination is determined as: spindle speed 2000 rpm, feed rate 0.18 mm/s, voltage 200 V, frequency 170 Hz. Corresponding predicted values are 35 N (drilling force), 61°C (temperature) and 1.05 μm (surface roughness). Validation experiments show that the prediction error of each indicator is within 15%, verifying the reliability of the proposed optimization method. Furthermore, when combined with drill bit pre-cooling, the drilling temperature decreased to 50.3°C, while drilling force and surface roughness remain at low levels. This study provides a low-damage, high-quality process parameter optimization method for bone drilling surgery, offering significant clinical application value.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"805-819"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148437701","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":"Computational fluid structure interaction analysis between aqueous humor and corneal shell.","authors":"Waleed J Al-Mashhadani, Nebras H Ghaeb, Taha Yaseen Khalaf, Mohd Shukor Salleh, Mohammed Alshekhly, Salah Al-Zubaidi, Oday I Abdullah","doi":"10.1177/09544119261467860","DOIUrl":"10.1177/09544119261467860","url":null,"abstract":"<p><p>This study uses a one-way coupled fluid-structure interaction (FSI) model of the anterior area to assess the velocity field and shear stress distribution on the corneal endothelium under healthy circumstances. Key anatomical measurements were included in the reconstruction of a physiologically appropriate three-dimensional geometry, including anterior chamber width of 3.42 mm and iridocorneal angle radii of 0.28 and 5.0 mm. For these parameters, a transient FSI study was conducted in ANSYS 2023. AH was shown as an incompressible Newtonian fluid with a constant input rate of (1.5-3.0 with a step of 0.5) µL/min to reproduce normal production. A linear elastic solid model represented the cornea, and limbal boundary conditions were imposed to replicate the physiological attachment of the tissue to the sclera. The transverse midplane velocity contours directed a parabolic shape with peak consequences near the chamber's geometric center. Regional heterogeneity in endothelial shear stress was estimated at the fluid-solid boundary. At peripheral curvature transitions, maximum stress concentrations correspond to R0.28 mm and R5 mm radii. The endothelial fluid wall shear stress (WSS) ranged from -129.19 to 129.32 Pa. Constant input creates a cyclic shear environment by reversing stress polarity across the cornea. Results show that aqueous flow produces endothelial shear stresses over 120 Pa, an order of magnitude greater than limits for mechanotransduction and cytoskeletal modification. The strong stress magnitude dependence on local curvature implies that angle geometry may affect mechanical sensitivity to corneal endothelium malfunction. This FSI paradigm confirms flow-induced shear as a significant, spatially altering mechanical input in the anterior chamber, furthering the pressure-centric IOP attitude. The model provides quantitative organization for patient-specific glaucomatous pathology and surgical planning investigations.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"836-846"},"PeriodicalIF":1.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148430872","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":"Surface roughness optimisation in FFF tibial insert patterns for silicone mould.","authors":"Raman Sharma, Narendra Kumar, Rajeev Trehan","doi":"10.1177/09544119261452432","DOIUrl":"10.1177/09544119261452432","url":null,"abstract":"<p><p>Most commercially available knee implant components are confined to standardised size ranges, hindering precise anatomical alignment and proper gap filling. This study focuses on producing silicone moulds for patient-specific knee implants using an indirect rapid tooling process. Total knee replacement (TKR) components were generated from CT scan data via image segmentation, CAD modelling, STL correction and resection planning. The profile for the tibial insert was extracted from the CAD models of femoral and tibial components of TKR. Further, the profile as obtained was employed to fabricate a pattern of the tibial insert by Fused Filament Fabrication (FFF) using PLA filaments. Two post-processing techniques, chemical immersion and chemical vapour smoothing, were used and compared to improve the surface finish. The more effective chemical vapour smoothing method was applied to the pattern. The effects on surface quality were assessed using an optical tilt microscope. The 3D surface plots confirmed that the post-processing improved the surface finish of the patterns by about 80%. Evaluation of geometric deviation confirmed that chemical vapour smoothing uniformly modifies the entire surface while maintaining global geometric conformity. The result encouraged us to fabricate the silicone moulds, which can further be used to produce patient-specific tibial inserts by casting viable epoxy-based composite biomaterials. FFF-fabricated tibial insert moulds showed Ra 26.87 µm, Rq 33.58 µm, Rsk -1.19, and Rku 3.12. Rapid tooling with an unsmoothed pattern increased roughness (Ra 54.60 µm, Rq 57.31 µm) and altered height distribution (Rsk 0.31, Rku 2.40). Vapour smoothing prior to moulding significantly reduced Rq and stabilised Rsk and Rku, indicating improved surface morphology and uniform asperity distribution.</p>","PeriodicalId":20666,"journal":{"name":"Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine","volume":" ","pages":"650-662"},"PeriodicalIF":1.8,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147988607","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}