1,721,016 research outputs found
Shape Memory Waterbomb Origami by Polylactic Acid Fused Filament Fabrication for Biomedical Devices
No full textMetodo e Apparato per la tessitura di modelli tridimensionali con immagini bidimensionali (brevetto)
No full textDesign and Characterization of Negative-Stiffness Lattice Structures for Diabetic Midsoles
Full text linkFeatured Application Negative-stiffness lattice structures represent a groundbreaking class of mechanical metamaterials capable of redistributing pressure in highly efficient and adaptive ways. Thanks to their unique ability to undergo localized deformation while maintaining global structural integrity, these lattices are ideal for applications requiring uniform load distribution, energy absorption, and enhanced comfort. From biomedical implants to aerospace panels and protective equipment, their tunable mechanical response opens new frontiers in design and performance.Abstract Diabetes mellitus often leads to peripheral neuropathy that compromises protective sensation in the feet and raises ulcer risk through mechanical overload. While prior research has introduced cellular-metamaterial-based shoe midsoles for dynamic plantar pressure redistribution, this study advances the field by delivering a complete, application-oriented workflow for physical prototyping and mechanical validation of such structures. Our pipeline integrates analytical synthesis of curved-beam unit cells, process calibration, and fabrication via thermoplastic polyurethane (TPU) fused-filament fabrication, producing customized, test-ready lattices suitable for future gait-simulation studies and in vivo assessment. Printed TPU tests showed a Young's modulus of 44.5 MPa, ultimate tensile strength of 4.9 MPa, and strain at break approximate to 20% (Shore 84.5 A/37.2 D). The cellular unit's compressive response was quantified by theoretical force-threshold estimates and controlled compression tests, enabling data-driven selection of unit cell geometry and arrangement for effective offloading. The response is rate-dependent: higher loading speed increases peak force and hysteresis, indicating that loading rate should be treated as a design parameter to tune dynamic behavior for the target application. Although the analytical model overestimates forces by roughly 50% on average relative to experiments, it accurately captures the influence of key geometric parameters on peak force. Accordingly, experimental data can identify cell strategic geometric parameters (i.e., Q), while the achievable maximum force can be predicted from the model by applying an appropriate correction factor. By connecting modeling, calibration, and experimental validation in one coherent path, the proposed workflow enables manufacturable lattices with controllable activation thresholds for plantar pressure redistribution and provides a practical bridge from concept to application
A Preliminary 3D Depth Camera-Based System to Assist Home Physiotherapy Rehabilitation
No full textTotal hip arthroplasty (THA) and total knee arthroplasty (TKA) have been recently heralded as the operations of the Century. Large improvements in mobility and patient-reported outcomes are typically observed compared with the small-to-moderate effects experienced with non-surgical interventions. Following surgery, physiotherapy-led exercise-based rehabilitation is often prescribed to yield better gait-related outcomes. Nevertheless, outpatient rehabilitation is expensive and heavily burden the national health service. When specific machines are not needed during the physiotherapy, patients, if assisted, can perform a home program. The purpose of this paper is to qualitatively investigate the applicability of a self-managed, home-based system for the automated evaluation of a home physiotherapy rehabilitation after TKA and THA. The system leverages the cost effectiveness and the versatility of a RGB-Depth camera system together with a commercial skeleton tracking system to analyse specific exercises. A novel computation of lower limb movements and related angles is proposed to evaluate the quality of the daily exercises. The laboratory experimental campaign, envisaged the analysis of the rotation angles of hips and knees; a lower limb schematic model is considered to estimate both knee and hip angles during ab/adductor and flex/extension movements. A novel real time calculation of the hip bone plane is proposed to assess the joint angles during specific exercises performance. A qualitative data analysis of each exercise has been performed. Results on the system usability in a domestic environment are reported as well as a visual comparison of the analysed output
Accurate Liver 3D Reconstruction from MRE Images Using Shift-Compensated Volumetric Interpolation
No full textIn the last decade, recognition of the diagnostic potential arising from the analysis of the mechanical properties of biological tissues has led to research into methods for determining the mechanical properties of in vivo tissues. Magnetic resonance elastography is a newly developed imaging technique, based on the study of the phase contrast of a propagated acoustic transmission wave in tissues subjected to harmonic mechanical excitation. The acquired data allow to calculate the local quantitative values of the shear modulus and the generation of images that, in the form of colored maps, represent the elasticity of the tissue. The main limit of this method is the limited number of images that can be acquired during a scan. This is reflected in the accuracy of the 3D reconstruction of the anatomy and leads to coarser segmentation and modeling. In this article, Motion Compensated Frame Interpolation techniques are applied for effective axial interpolation of magnetic resonance elastography image sequences, with the main goal of achieving a refined 3D reconstruction
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