13,176 research outputs found
Author Correction: Evaluation of skin cancer resection guide using hyper‑realistic in‑vitro phantom fabricated by 3D printing
No full textThe original version of this Article contained an error in the spelling of the author Taehun Kim which was incorrectly given as Teahun Kim. The original Article has been corrected
Additively Manufactured Mechanical Metamaterial‐Based Pressure Sensor with Tunable Sensing Properties for Stance and Motion Analysis
No full textMechanical metamaterials are attracting considerable attention due to their unique properties not found in natural materials. Advanced geometrical shapes such as Menger cubes, origami templates, and gyroids offer exciting avenues for device engineering. In addition, the recent developments of various additive manufacturing technologies have expanded materials selection and geometrical complexities. Herein, a piezoresistive pressure sensor based on a 3D-printed gyroid structure with a conformal coating of carbon nanotubes (CNTs) is presented. The gyroid structures are printed using fused deposition modeling (FDM) 3D printing with thermoplastic polyurethane (TPU), providing mechanical robustness even at low densities. By altering the relative density of the gyroid structure, Young's modulus can be tailored, ranging from 0.32 MPa at 30% relative density and 3.61 MPa at 80% relative density. The presented gyroid-based pressure sensor achieves a wide sensing range of up to 1.45 MPa and a high sensitivity of 2.68 MPa−1. The sensor is integrated into a shoe for wearable applications, demonstrating its mechanical robustness and potential for human stance and motion monitoring. © 2023 Wiley-VCH GmbH.TRUEsciescopu
In vivo high spatiotemporal resolution visualization of circulating T lymphocytes in high endothelial venules of lymph nodes
No full textLymph nodes (LN) are major checkpoints for circulating T lymphocytes to recognize foreign antigens collected from peripheral tissue. High endothelial venule (HEV) in LN facilitates the effective transmigration of circulating T lymphocytes from the blood into LN. There have been many efforts to visualize T lymphocytes trafficking across HEV to understand the underlying mechanism. However, due to insufficient spatiotemporal resolution and the lack of an in vivo labeling method, clear visualization of dynamic behaviors of rapidly flowing T lymphocytes in HEV and their transmigration have been difficult. In this work, we adapted a custom-designed video-rate laser scanning confocal microscopy system to track individual flowing T lymphocytes in the HEV in real time in vivo. We demonstrate that the HEVs in LN can be clearly identified in vivo with its distinctive cuboidal morphology of endothelial cells fluorescently labeled by intravenously injected anti-CD31 antibody conjugated with Alexa fluorophore. By visualizing the adaptively transferred T lymphocytes, we successfully analyzed dynamic flowing behaviors of T lymphocytes and their transendothelial migration while interacting with the endothelial cells in HEV. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI
Magnetochromatic Microactuators for a Micropixellated Color-Changing Surface
No full textA magnetically tunable chromatic nanocomposite microactuator is proposed, which utilizes the optical and magnetic behaviors of self-assembled super-paramagnetic nanoparticles fixed in a polymeric microstructure. The original color can be programmed during a simple photolithography process, and the color can be changed just by applying and changing an external magnetic field. These microactuators are capable of acting as pixels in a color-changing pattern. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.101211sciescopu
Additive-Free Gelation of Graphene Oxide Dispersions via Mild Thermal Annealing: Implications for 3D Printing and Supercapacitor Applications
No full textHerein, a mild thermal annealing (MTA) process is presented for additive-free gelation of graphene oxide (GO) dispersions. This process transitions the GO from a nematic liquid crystal phase to a random network structure, significantly enhancing its rheological properties by order of magnitude. This transition is facilitated by the diffusion of functional groups on the GO surface, which induces hydrophobic attractions, leading to a stable network structure. Employing rheo-SAXS experiments, detailed insights are provided into the microstructural changes of GO gel under shear stress, establishing a direct correlation between its rheological behavior and microstructure. The distinctive properties of MTA-processed inks are illustrated, seamlessly integrating with 3D printing, to yield a highly porous lattice structure that demonstrates promising potential as a supercapacitor electrode. The MTA process, an additive-free approach to gelation, maintains the inherent dispersion properties of GO while offering scalability. Thus, this method brings significant economic and environmental advantages compared to conventional gelation techniques. The findings not only advance the fundamental understanding of 2D colloidal network gels but also increase the potential of GO for a wide range of applications, from gas and liquid absorbers to electrodes for energy storage and conversion, and biomedical fields.N
Improving Surface Roughness of Additively Manufactured Parts Using a Photopolymerization Model and Multi-Objective Particle Swarm Optimization
No full textAlthough additive manufacturing (AM) offers great potential to revolutionize modern manufacturing, its layer-by-layer process results in a staircase-like rough surface profile of the printed part, which degrades dimensional accuracy and often leads to a significant reduction in mechanical performance. In this paper, we present a systematic approach to improve the surface profile of AM parts using a computational model and a multi-objective optimization technique. A photopolymerization model for a micro 3D printing process, projection micro-stereolithography (PμSL), is implemented by using a commercial finite element solver (COMSOL Multiphysics software). First, the effect of various process parameters on the surface roughness of the printed part is analyzed using Taguchi’s method. Second, a metaheuristic optimization algorithm, called multi-objective particle swarm optimization, is employed to suggest the optimal PμSL process parameters (photo-initiator and photo-absorber concentrations, layer thickness, and curing time) that minimize two objectives; printing time and surface roughness. The result shows that the proposed optimization framework increases 18% of surface quality of the angled strut even at the fastest printing speed, and also reduces 50% of printing time while keeping the surface quality equal for the vertical strut, compared to the samples produced with non-optimized parameters. The systematic approach developed in this study significantly increase the efficiency of optimizing the printing parameters compared to the heuristic approach. It also helps to achieve 3D printed parts with high surface quality in various printing angles while minimizing printing time
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