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

Similar to how fiber orientation affects composite materials, osteon orientation affects the elasticity and fracture behavior of cortical bone. The objective of this work is to predict the combined effect of orientations of the osteon, applied load, and various crack lengths on the fracture characteristics of cortical bone. Orthotropic modeling and analyses of cortical bone were carried out using the linear-elastic fracture mechanics (LEFM) based extended finite element method (XFEM). Five values of applied mode-I and mode-II load, five distinct crack lengths, and seven angular osteon orientations were taken into consideration to predict the change in SIF. In this work, the 2-D plane stress assumption with a straight-edge crack was taken into consideration. It was found that the values of SIF significantly increased when the load (15-35 MPa) and fracture length (1.8-2.2 mm) increased. SIF (K_I) values under mode-I loading were discovered to be substantially lower than SIF (K_I and K_II) values under mode-II loading. Results of this study showed that osteon orientations with different crack lengths and applied loads had a significant impact on cortical bone fracture characteristics. Only the crack's opening was discovered to be caused by mode-I loading; however, both the opening and shearing of the crack were found to be caused by mode-II loading. Despite differences in applied loads, crack lengths, and osteon orientations, the values of the SIF predicted in this work (under mode-I loading) using LEFM-based XFEM exhibited good agreement with the prior published experimental and numerical data.

This investigation attempts to propose a novel Wavelet and Local Binary Pattern-based Xception feature Descriptor (WLBPXD) framework, which uses a deep-learning model for classifying chronic infection amongst other infections. Chronic infection (COVID-19 in this study) is identified via RT-PCR test, which is time-consuming and requires a dedicated laboratory (materials, equipment, etc.) to complete the clinical results. X-rays and computed tomography images from chest scans offer an alternative method for identifying chronic infections. It has been demonstrated that chronic infection can be diagnosed from X-ray images acquired in a real-world setting. The images are transformed using the discrete wavelet transform (DWT), combined with the local binary pattern (LBP) technique. Pre-trained deep-learning models, such as AlexNet, Xception, VGG-16 and Inception Resnet50, extract the features. Subsequently, the extracted features are fused using feature-fusion approaches and subjected to classification. The AlexNet, in conjunction with the DWT model, produced 99.7% accurate results, whereas the AlexNet and the LBP model produced 99.6% accurate results. Therefore, the proposed method is efficient as it offers a better detection accuracy and eventually enhances the scope of early detection, thus assisting the clinical perspectives.

The purpose of this paper is to undertake a systematic review on various mechanical design considerations, simulation and optimization techniques as well as the clinical applications of energy storing and return (ESAR) prosthetic feet used in amputee rehabilitation. Methodological databases including PubMed, EMBASE, and SCOPUS were searched till July 2022, and the retrieved records were evaluated for relevance. The design, mechanism, materials used, mechanical and simulation techniques and clinical applications of ESAR foot used in developed and developing nations were reviewed. 61 articles met the inclusion criteria out of total 577 studies. A wide variety of design matrices for energy- storing feet was found, but the clinical relevance of its design parameters is uncommon. Definitive factors on technical and clinical characteristics were derived and included in the summary tables. To modify existing foot failure mechanisms, material selection and multiple experiments must be improved. Gait analysis and International Organization for Standardization (ISO) mechanical testing standards of energy-storing feet were the methods for integrating clinical experimentation with numerical results. To meet technological requirements, various frameworks simulate finite element models of the energy-storing foot, whereas clinical investigations involving gait analysis require proper insight. Analysis of structural behavior under varying loads and its effect on studies of functional gait are limited. For optimal functional performance, durability and affordability, more research and technological advancements are required to characterize materials and standardize prosthetic foot protocols.

In this review, user experience (UX) of recent lower limb exoskeletons (LLEs) and its improvement methodologies are investigated. First, statistics based on standardised and custom UX evaluations are presented. It is indicated that, LLE users have positive UX, especially in the aspects of safety, dimension and effectiveness. Further, overall, UX levels of ankle and hip-knee exoskeletons are higher than those of other exoskeleton types; unilateral LLEs have higher mean UX levels than that of the bilateral ones. Then, design practices for improving UX are studied; the focused points are burden reduction and improvement of device fit. The former is achieved through lightweight design and approaches that reduce device's moment of inertia (MOI) at mechanical joints. Works on the latter refer to the endeavours to enhance static and dynamic fit; they mainly rely on the optimisations of human-robot interface (HRS) and endeavours to rectify misalignment of axes of mechanical and anatomic joints, respectively. The following section is control approaches to enhance wearing comfort level; it is mainly focused on adaptive, interaction and compensation-based controls. Finally, existing problems and future directions are stated and prospected respectively.

Bulk metallic glasses (BMGs) have garnered significant attention in recent decades due to the outstanding physical, chemical, and biomedical characteristics. The biomedical application of metallic glass also received extensive attention. This report investigates the interplay among antibacterial performance, crystallization and processing parameters of Zr-based bulk metallic glass (Zr-BMG) following nanosecond laser irradiation. We examined surface morphology, crystallization behavior, surface quality, binding energy, and ion release properties post-laser irradiation. Additionally, we evaluated the generation of reactive oxygen species upon immersion of Zr-BMG in phosphate-buffered saline using the 2',7'-dichlorofluorescin diacetate method. Staphylococcus aureus was chosen to assess Zr-BMG's antibacterial performance, while mouse osteoblasts were utilized to investigate in vitro cytotoxicity. Our findings revealed that at laser energy intensities below 0.08 J/mm², the amorphous structure of Zr-BMG remained intact after irradiation. Moreover, laser irradiation significantly enhanced the antibacterial performance of Zr-BMG. The release rate of ion, concentration of reactive oxygen species, and antibacterial properties exhibited direct proportionality to laser energy intensity. However, surfaces exhibiting high antibacterial efficacy also displayed elevated cytotoxicity. The surface irradiated with a 7 μJ ablation pulse and 200 mm/s irradiation speed demonstrated a superior balance between antibacterial and cytotoxic properties while maintaining an amorphous state. We hope this research can provide theoretical reference and data support for the application of metallic glass in biomedical application.

Bone ingrowth into a porous implant is necessary for its long-term fixation. Although attempts have been made to quantify the peri-implant bone growth using finite element (FE) analysis integrated with mechanoregulatory algorithms, bone ingrowth into a porous cellular hip stem has scarcely been investigated. Using a three-dimensional (3D) FE model and mechanobiology-based numerical framework, the objective of this study was to predict the spatial distribution of evolutionary bone ingrowth into an uncemented novel porous hip stem proposed earlier by the authors. A CT-based FE macromodel of the implant-bone structure was developed. The bone material properties were assigned based on CT grey value. Peak musculoskeletal loading conditions, corresponding to level walking and stair climbing, were applied. The geometry of the implant-bone macromodel was divided into multiple submodels. A suitable mapping framework was used to transfer maximum nodal displacements from the FE macromodel to the cut boundaries of the FE submodels. CT grey value-based bone materials properties were assigned to the submodels. Thereafter, the submodels were solved and simulations of bone ingrowth were carried out using mechanoregulatory principle. A gradual increase in the average Young's modulus, from 1200 to 1500 MPa, of the bone tissue layer was observed considering all the submodels. The distal submodel exhibited 82% of bone ingrowth, whereas the proximal submodel experienced 65% bone ingrowth. Equilibrium in the bone ingrowth process was achieved in 7 weeks postoperatively, with a notable amount of bone ingrowth that should lead to biological fixation of the novel hip stem.

Polyether-ether-ketone (PEEK) has been widely applied in various fields due to its excellent mechanical properties and biocompatibility. The efficient and high-quality customized manufacturing of PEEK components are investigated in this study by the hybrid 3D printing and milling process. At first, the alternating hybrid process is selected and verified by comparing two typical hybrid process categories and conducting experiments, respectively. Second, a set of procedures are designed to automate the engineering application of the hybrid process trying to avoid the disadvantages of manual programing. Then, considering the tool length and possible interferences during the hybrid process, a model segmentation algorithm, namely, the exchange principle of avoiding interference (EPAI) is proposed. Based on the introduced EPAI and the programing language Python, the additive and subtractive hybrid manufacturing (ASHM) data processing procedure is proposed and realized by post-processing of the conventional 3D printing codes. Finally, the feasibility experiments have been conducted. The experimental results verify the hybrid manufacturing process in the fabrication of parts with complex internal features. The surface roughness R_a and dimensional error L of the parts have been reduced by 75.5% and 85.2%, respectively, while the shear strength τ has been increased by 14.1%. Compared with conventional milling process, the material consumption is reduced by 48.7%.

An asymmetric windswept posture is often seen in children with severe cerebral palsy (CP). However, it is still unclear how long children with CP remain in the windswept posture in daily life. Thus, we developed a triple-accelerometer system for detecting windswept posture. The aim of this study was to assess the validity of a system for classifying various body postures and movements. We assessed the accuracy of our system in nine healthy young adults (age range, 21-23 years). The participants wore acceleration monitors on the sternum and both thighs, then spent 3 min each in eight different positions and three physical activities. Once accuracy was confirmed, we assessed the posture and movements for 24 h in six healthy young adults (age range, 21-23 years) in their home environments. The body postures and activities were correctly detected: the agreement across the subjects were 100% compatible with the subjects' activity logs at least 68% of the time, and at least 96% of the time for recumbent positions. We concluded that the proposed monitoring system is a reliable and valid approach for assessing windswept hip posture in a free-living setting.

Additive Manufacturing (AM) encompasses various techniques creating intricate components from digital models. The aim of incorporating 3D printing (3DP) in the healthcare sector is to transform patient care by providing personalized solutions, improving medical procedures, fostering research and development, and ultimately optimizing the efficiency and effectiveness of healthcare delivery. This review delves into the historical beginnings of AM's 9 integration into medical contexts exploring various categories of AM methodologies and their roles within the medical sector. This survey also dives into the issue of material requirements and challenges specific to AM's medical applications. Emphasis is placed on how AM processes directly enhance human well-being. The primary focus of this paper is to highlight the evolution and incentives for cross-disciplinary AM applications, particularly in the realm of healthcare by considering their principle, materials and applications. It is designed for a diverse audience, including manufacturing professionals and researchers, seeking insights into this transformative technology's medical dimensions.

As the natural conclusion of talent identification in sports, talent development is the process that involves improving biomechanical capacities and bio-motor abilities. The development progress can be objectively assessed and monitored through measurements of trainability. This study introduces a practical methodology to assess motor control as a trainable factor using kinematic data. The study focused on establishing the relationship between kinematic data and changes in muscle strength and dynamic balance. It illustrates how wearable technology can assess trainability during a functional training programme. Twenty-six female university students were selected and divided into intervention and control groups to investigate motor control trainability. The intervention group performed step aerobics exercises for 24 sessions. A single inertial measurement unit (IMU) mounted on S1 captured the oscillatory motion profiles of the centre of mass during these rhythmic exercises. Analysis revealed that the amplitude of linear jerk variability in different anatomical planes could reflect core and lower limb muscle strengthening caused by training. Furthermore, the results indicated that the dynamic balance adaptation to the changing tempo throughout the training programme was dictated primarily by step width. The mediolateral linear jerk variability reflected this adaptation. The minimum instrumentation approach proposed by this study could prove very practical for the talent development monitoring. The methodology illustrates how the recorded kinematic data from an appropriately placed single IMU could become an information-rich source for the coach to monitor, assess and quantify the trainee's progress during long-term athletic development.