Bundles of filaments are subject to geometric frustration: certain deformations (e.g., bending while twisted) require longitudinal variations in spacing between filaments. While bundles are common-from protein fibers to yarns-the mechanical consequences of longitudinal frustration are unknown. We derive a geometrically nonlinear formalism for bundle mechanics, using a gaugelike symmetry under reptations along filament backbones. We relate force balance to orientational geometry and assess the elastic cost of frustration in twisted-toroidal bundles.
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http://dx.doi.org/10.1103/PhysRevLett.127.218002 | DOI Listing |
Nanomaterials (Basel)
February 2025
Centro de Ciências e Tecnologias Nucleares (C2TN), Departamento de Engenharia e Ciências Nucleares (DECN), Instituto Superior Técnico, Universidade de Lisboa, Campus Tecnológico e Nuclear, 2695-066 Bobadela, Portugal.
Thermoelectric (TE) materials offer a promising solution to reduce green gas emissions, decrease energy consumption, and improve energy management due to their ability to directly convert heat into electricity and vice versa. Despite their potential, integrating new TE materials into bulk TE devices remains a challenge. To change this paradigm, the preparation of highly efficient tetrahedrite nanocomposites is proposed.
View Article and Find Full Text PDFArtif Organs
March 2025
Cardiovascular Institute, Thorax Center, Department of Cardiology, Erasmus Medical Center, Rotterdam, the Netherlands.
Objectives: Marginal donor kidneys are increasingly used for transplantation to overcome organ shortage. This study aims to investigate the additional value of Power Doppler (PD) imaging in kidney quality assessment during normothermic machine perfusion (NMP).
Methods: Porcine kidneys (n = 22) retrieved from a local slaughterhouse underwent 2 h of NMP.
Wearable Technol
February 2025
Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands.
State-of-the-art controllers for active back exosuits rely on body kinematics and state machines. These controllers do not continuously target the lumbosacral compression forces or adapt to unknown external loads. The use of additional contact or load detection could make such controllers more adaptive; however, it can be impractical for daily use.
View Article and Find Full Text PDFWearable Technol
March 2025
Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA.
Eye gaze tracking is increasingly popular due to improved technology and availability. In the domain of assistive device control, however, eye gaze tracking is often used in discrete ways (e.g.
View Article and Find Full Text PDFJ Magn Reson Imaging
March 2025
Center for Biomedical Imaging Research, School of Biomedical Engineering, Tsinghua University, Beijing, China.
Background: MR cytometry is a class of diffusion-MRI-based methods that characterize tumor microstructures at the cellular level. It involves multicompartmental biophysical modeling of multi-b and multiple diffusion time data to generate microstructural parameters, which may improve differentiation of benign and malignant breast tumors.
Purpose: To implement MR cytometry imaging with transcytolemmal water exchange (JOINT and EXCHANGE) to differentiate benign and malignant breast tumors, and to compare the classification efficacy of IMPULSED, JOINT, and EXCHANGE.
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