2,360 results match your criteria shape stiffness

3D Printing Improved Testicular Prostheses: Using Lattice Infill Structure to Modify Mechanical Properties.

Front Surg 2021 20;8:626143. Epub 2021 Apr 20.

Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia.

Patients often opt for implantation of testicular prostheses following orchidectomy for cancer or torsion. Recipients of testicular prostheses report issues regarding firmness, shape, size, and position, aspects of which relate to current limitations of silicone materials used and manufacturing methods for soft prostheses. We aim to create a 3D printable testicular prosthesis which mimics the natural shape and stiffness of a human testicle using a lattice infill structure. Read More

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Adverse immunological responses against non-viral nanoparticle (NP) delivery systems in the lung.

J Immunotoxicol 2021 Dec;18(1):61-73

Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK.

There is a large, unmet medical need to treat chronic obstructive pulmonary disease, asthma, idiopathic pulmonary fibrosis and other respiratory diseases. New modalities are being developed, including gene therapy which treats the disease at the DNA/RNA level. Despite recent innovations in non-viral gene therapy delivery for chronic respiratory diseases, unwanted or adverse interactions with immune cells, particularly macrophages, can limit drug efficacy. Read More

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December 2021

Enhanced Electroactivity, Mechanical Properties, and Printability through the Addition of Graphene Oxide to Photo-Cross-linkable Gelatin Methacryloyl Hydrogel.

ACS Biomater Sci Eng 2021 May 6. Epub 2021 May 6.

ARC Centre of Excellence for Electromaterials Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria 3122, Australia.

The human tissues most sensitive to electrical activity such as neural and muscle tissues are relatively soft, and yet traditional conductive materials used to interface with them are typically stiffer by many orders of magnitude. Overcoming this mismatch, by creating both very soft and electroactive materials, is a major challenge in bioelectronics and biomaterials science. One strategy is to imbue soft materials, such as hydrogels, with electroactive properties by adding small amounts of highly conductive nanomaterials. Read More

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A numerical investigation of changes in lens shape during accommodation.

Sci Rep 2021 May 5;11(1):9639. Epub 2021 May 5.

Aragón Institute of Engineering Research (i3A), University of Zaragoza, Mariano Esquillor s/n, Zaragoza, 50018, Spain.

The purpose of this study was to investigate how the mechanical properties and geometry of the lens influence the changes in lens shape during accommodation. To do so, ex vivo stretching tests of the isolated lens were simulated via finite element analysis. In these tests, the lens is stretched from the accommodated state to the non-accommodated state. Read More

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Effect of body stiffness distribution on larval fish-like efficient undulatory swimming.

Sci Adv 2021 May 5;7(19). Epub 2021 May 5.

Physical Intelligence Department, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany.

Energy-efficient propulsion is a critical design target for robotic swimmers. Although previous studies have pointed out the importance of nonuniform body bending stiffness distribution () in improving the undulatory swimming efficiency of adult fish-like robots in the inertial flow regime, whether such an elastic mechanism is beneficial in the intermediate flow regime remains elusive. Hence, we develop a class of untethered soft milliswimmers consisting of a magnetic composite head and a passive elastic body with different These robots realize larval zebrafish-like undulatory swimming at the same scale. Read More

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Polymer-coated microparticle scaffolds engineered for potential use in musculoskeletal tissue regeneration.

Biomed Mater 2021 May 4. Epub 2021 May 4.

Department of Oral and Craniofacial Sciences, University of Missouri Kansas City School of Dentistry, 650 E 25th St, Kansas City, Missouri, 64108-2716, UNITED STATES.

Biomaterials constructed exclusively of sintered microspheres have great potential in tissue engineering scaffold applications, offering the ability to create shape-specific scaffolds with precise controlled release yet to be matched by traditional additive manufacturing methods. The problem is that these microsphere-based scaffolds are limited in their stiffness for applications such as bone regeneration. Our vision to solve this problem was borne from a hierarchical structure perspective, focusing on the individual unit of the structure: the microsphere itself. Read More

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Analytical methods for braided stents design and comparison with FEA.

J Mech Behav Biomed Mater 2021 Apr 24;119:104560. Epub 2021 Apr 24.

Dept. of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy. Electronic address:

Braiding technology is nowadays commonly adopted to build stent-like devices. Indeed, these endoprostheses, thanks to their typical great flexibility and kinking resistance, find several applications in mini-invasive treatments, involving but not limiting to the cardiovascular field. The design process usually involves many efforts and long trial and error processes before identifying the best combination of manufacturing parameters. Read More

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Study of Optimal Cam Design of Dual-Axle Spring-Loaded Camming Device.

Materials (Basel) 2021 Apr 13;14(8). Epub 2021 Apr 13.

Department of Applied Mechanics, Faculty of Mechanical Engineering, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava, Czech Republic.

The spring-loaded camming device (SLCD), also known as "friend", is a simple mechanism used to ensure the safety of the climber through fall prevention. SLCD consists of two pairs of opposing cams rotating separately, with one (single-axle SLCD) or two (dual-axle SLCD) pins connecting the opposing cams, a stem, connected to the pins, providing the attachment of the climbing rope, springs, which simultaneously push cams to a fully expanded position, and an operating element controlling the cam position. The expansion of cams is thus adaptable to allow insertion or removal of the device into/from a rock crack. Read More

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Electrospun Shape Memory Polymer Micro-/Nanofibers and Tailoring Their Roles for Biomedical Applications.

Nanomaterials (Basel) 2021 Apr 6;11(4). Epub 2021 Apr 6.

Department of Mechanical Engineering, Center for Nanofibers and Nanotechnology, National University of Singapore, Singapore 119260, Singapore.

Shape memory polymers (SMPs) as a relatively new class of smart materials have gained increasing attention in academic research and industrial developments (e.g., biomedical engineering, aerospace, robotics, automotive industries, and smart textiles). Read More

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Evaluation of non-invasive arterial stiffness parameters and their relationship with physical activity, anthropometric indices and lipid profiles in healthy middle-aged adults: results of the PERSIAN cohort study.

Int J Clin Pract 2021 Apr 29:e14275. Epub 2021 Apr 29.

Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

Background: Arterial stiffness (AS) indicates the initial stage of cardiovascular disease (CVD), which associated with modifiable and lifestyle risk factors. We aimed to examine the association of AS with anthropometric indices, lipid profiles, and physical activity.

Methods: 658 healthy middle-aged adults selected and anthropometric indices (body mass index (BMI), waist circumferences (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), neck circumferences (NC), a body shape index (ABSI), body roundness index (BRI), body-fat mass (BFM), visceral-fat, fat-free mass(FFM), lipid profiles, and PA were measured. Read More

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Solvent-Free UV Polymerization of -Octadecyl Acrylate in Butyl Rubber: A Simple Way to Produce Tough and Smart Polymeric Materials at Ambient Temperature.

ACS Appl Mater Interfaces 2021 Apr 28. Epub 2021 Apr 28.

Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey.

One of the most fascinating challenges in recent years has been to produce mechanically robust and tough polymers with smart functions such as self-healing and shape-memory behavior. Here, we report a simple and versatile strategy for the preparation of a highly tough and highly stretchable interconnected interpenetrating polymer network (c-IPN) based on butyl rubber (IIR) and poly(-octadecyl acrylate) (PC18A) with thermally induced healing and shape-memory functions. Solvent-free UV polymerization of -octadecyl acrylate (C18A) at 30 ± 2 °C in the presence of IIR leads to IIR/PC18A c-IPNs with sea-island or co-continuous morphologies depending on their IIR contents. Read More

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Sonographic Features of Abscess Maturation in a Porcine Model.

Ultrasound Med Biol 2021 Apr 23. Epub 2021 Apr 23.

Applied Physics Laboratory, University of Washington, Seattle, Washington, USA.

Abscesses are walled-off collections of infected fluids that often develop as complications in the setting of surgery and trauma. Treatment is usually limited to percutaneous catheterization with a course of antibiotics. As an alternative to current treatment strategies, a histotripsy approach was developed and tested in a novel porcine animal model. Read More

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Glioma stem cells invasive phenotype at optimal stiffness is driven by MGAT5 dependent mechanosensing.

J Exp Clin Cancer Res 2021 Apr 24;40(1):139. Epub 2021 Apr 24.

Institut des Neurosciences de Montpellier (INM) U-1051, University of Montpellier, 80 rue Augustin Fliche, Hôpital Saint-Eloi, 34091, Montpellier, Cedex 5, France.

Background: Glioblastomas stem-like cells (GSCs) by invading the brain parenchyma, remains after resection and radiotherapy and the tumoral microenvironment become stiffer. GSC invasion is reported as stiffness sensitive and associated with altered N-glycosylation pattern. Glycocalyx thickness modulates integrins mechanosensing, but details remain elusive and glycosylation enzymes involved are unknown. Read More

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Spatiotemporal patterning of photoresponsive DNA-based hydrogels to tune local cell responses.

Nat Commun 2021 04 22;12(1):2364. Epub 2021 Apr 22.

Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, Israel.

Understanding the spatiotemporal effects of surface topographies and modulated stiffness and anisotropic stresses of hydrogels on cell growth remains a biophysical challenge. Here we introduce the photolithographic patterning or two-photon laser scanning confocal microscopy patterning of a series of o-nitrobenzylphosphate ester nucleic acid-based polyacrylamide hydrogel films generating periodically-spaced circular patterned domains surrounded by continuous hydrogel matrices. The patterning processes lead to guided modulated stiffness differences between the patterned domains and the surrounding hydrogel matrices, and to the selective functionalization of sub-regions of the films with nucleic acid anchoring tethers. Read More

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Shape switching of CaCO-templated nanorods into stiffness-adjustable nanocapsules to promote efficient drug delivery.

Acta Biomater 2021 Apr 17. Epub 2021 Apr 17.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China. Electronic address:

Geometry and mechanical property have emerged as important parameters in designing nanocarriers, in addition to their size, surface charge, and hydrophilicity. However, inconsistent and even contradictory demands regarding the shape and stiffness of nanoparticles have been noted in blood circulation, tumor accumulation, and tumor cell internalization. Herein, CaCO nanorods (NRs) with an aspect ratio of around 2. Read More

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A pair of particles in inertial microfluidics: effect of shape, softness, and position.

Soft Matter 2021 Apr 19. Epub 2021 Apr 19.

Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany.

Lab-on-a-chip devices based on inertial microfluidics have emerged as a promising technique to manipulate particles in a precise way. Inertial microfluidics exploits internal hydrodynamic forces and the mechanical structure of particles to achieve separation and focusing. The article focuses on the hydrodynamic interaction of two particles. Read More

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Evaluating Poly(Acrylamide-co-Acrylic Acid) Hydrogels Stress Relaxation to Direct the Osteogenic Differentiation of Mesenchymal Stem Cells.

Macromol Biosci 2021 Apr 19:e2100069. Epub 2021 Apr 19.

Department of mining, metallurgy, and materials engineering, Surface Engineering Laboratory, Research Center on Advanced Materials, Laval University, 1065 Avenue de la médecine, Québec, G1V 0A6, Canada.

The aim of this study is to investigate polyacrylamide-based hydrogels stress relaxation and the subsequent impact on the osteogenic differentiation of human mesenchymal stem cells (hMSCs). Different hydrogels are synthesized by varying the amount of cross-linker and the ratio between the monomers (acrylamide and acrylic acid), and characterized by compression tests. It has been found that hydrogels containing 18% of acrylic acid exhibit an average relaxation of 70%, while pure polyacrylamide gels show an average relaxation of 15%. Read More

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Walrus large bore guide catheter impact on recanalization first pass effect and outcomes: the WICkED study.

J Neurointerv Surg 2021 Apr 15. Epub 2021 Apr 15.

Lyerly Neurosurgery, Baptist Neurological Institute, Jacksonville, Florida, USA

Background: The use of a balloon-guide catheter (BGC) in acute stroke treatment has been widely adopted after demonstrating optimized procedure metrics and outcomes. Initial technical constraints of previous devices included catheter stiffness and smaller inner diameters. We aim to evaluate the performance and safety of the Walrus BGC, a variable stiffness catheter with a large bore 0. Read More

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Liquid-induced topological transformations of cellular microstructures.

Nature 2021 Apr 14;592(7854):386-391. Epub 2021 Apr 14.

Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.

The fundamental topology of cellular structures-the location, number and connectivity of nodes and compartments-can profoundly affect their acoustic, electrical, chemical, mechanical and optical properties, as well as heat, fluid and particle transport. Approaches that harness swelling, electromagnetic actuation and mechanical instabilities in cellular materials have enabled a variety of interesting wall deformations and compartment shape alterations, but the resulting structures generally preserve the defining connectivity features of the initial topology. Achieving topological transformation presents a distinct challenge for existing strategies: it requires complex reorganization, repacking, and coordinated bending, stretching and folding, particularly around each node, where elastic resistance is highest owing to connectivity. Read More

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EpCAM promotes endosomal modulation of the cortical RhoA zone for epithelial organization.

Nat Commun 2021 04 13;12(1):2226. Epub 2021 Apr 13.

Cell Adhesion and Mechanics, Institut Jacques Monod, CNRS UMR7592, Paris Diderot University, Paris, France.

At the basis of cell shape and behavior, the organization of actomyosin and its ability to generate forces are widely studied. However, the precise regulation of this contractile network in space and time is unclear. Here, we study the role of the epithelial-specific protein EpCAM, a contractility modulator, in cell shape and motility. Read More

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Comparison of 2 shear wave elastography systems in reproducibility and accuracy using an elasticity phantom.

Medicine (Baltimore) 2021 Apr;100(15):e24921

Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Abstract: This study aimed to compare the accuracy and inter- and intra-observer reproducibility of the measured elasticity between 2 shear wave elastography systems. Three breast radiologists examined 8 targets of 4 different levels of stiffness (size: 11 mm, 4 mm) in an elasticity phantom (Customized 049A Elasticity QA Phantom, CIRS, Norfolk, VA, USA) using 2 different shear wave ultrasound elastography systems: SuperSonic Imagine (SSI) (SSI, Aix en Provence, France) and ShearScan (RS-80A, Samsung Medison, Seoul, Korea). Three radiologists performed ultrasound (US) elastography examinations for the phantom lesions using 2 equipment over a 1-week interval. Read More

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Color-Changeable Four-Dimensional Printing Enabled with Ultraviolet-Curable and Thermochromic Shape Memory Polymers.

ACS Appl Mater Interfaces 2021 Apr 8;13(15):18120-18127. Epub 2021 Apr 8.

National Research Center for High-Efficiency Grinding, College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, P. R. China.

Four-dimensional (4D) printing, which enables 3D printed structures to alter shapes over time, is attracting increasing attention because of its exciting potential in various applications. Among all the 4D printing materials, shape memory polymers (SMPs) have a higher stiffness and faster response rate and therefore are considered as one of the most promising 4D printing materials. However, the current studies of SMP-based 4D printing mainly focused on the deformation behavior and structural design of 4D printed structures. Read More

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Rapid fabrication technique for aluminum optics by inducing a MRF contamination layer modification with Ar ion beam sputtering.

Opt Express 2021 Mar;29(6):8951-8966

Aluminum optics are widely used in modern optical systems because of high specific stiffness and high reflectance. Magnetorheological finishing (MRF) provides a highly deterministic technology for high precision aluminum optics fabrication. However, the contamination layer will generate on the surface and bring difficulties for the subsequent processes, which highly limit the fabrication efficiency and precision. Read More

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Mechanical Behavior and Morphological Study of Polytetrafluoroethylene (PTFE) Composites under Static and Cyclic Loading Condition.

Materials (Basel) 2021 Mar 31;14(7). Epub 2021 Mar 31.

Faculty of Materials Engineering and Physics, Institute of Materials Engineering, Tadeusz Kosciuszko Cracow University of Technology, al. Jana Pawła II 37, 31-864 Cracow, Poland.

The key goal of this study was to characterize polytetrafluoroethylene (PTFE) based composites with the addition of bronze particles and mineral fibers/particles. The addition of individual fillers was as follows: bronze-30-60 wt.%, glass fibers-15-25 wt. Read More

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Design of Customize Interbody Fusion Cages of Ti64ELI with Gradient Porosity by Selective Laser Melting Process.

Micromachines (Basel) 2021 Mar 15;12(3). Epub 2021 Mar 15.

Hong Kong Institute for Advanced Study, Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong.

Intervertebral fusion surgery for spinal trauma, degeneration, and deformity correction is a major vertebral reconstruction operation. For most cages, the stiffness of the cage is high enough to cause stress concentration, leading to a stress shielding effect between the vertebral bones and the cages. The stress shielding effect affects the outcome after the reconstruction surgery, easily causing damage and leading to a higher risk of reoperation. Read More

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Study of Selected Physical-Mechanical Properties of Corn Grains Important from the Point of View of Mechanical Processing Systems Designing.

Materials (Basel) 2021 Mar 17;14(6). Epub 2021 Mar 17.

Department of Machines and Technical Systems, Faculty of Mechanical Engineering, University of Science and Technology in Bydgoszcz, 85-796 Bydgoszcz, Poland.

Mechanical properties of corn grains are of key importance in a design of processing machines whose energy demand depends on these properties. The aim of this study is to determine the selected mechanical properties of corn grains and the rupture energy. The research problem was formulated as questions: (1) How much force and energy is needed to induce a rupture of corn grain maintaining good quality of the product of processing (mixing, grinding transport)? (2) Can empirical distributions of the studied physical-mechanical properties be described by means of probability distributions provided by the literature? (3) Is there a relationship between the corn grain size and the selected mechanical properties, as well as rupture energy? In order to achieve the goals, the selected physical properties (size, volume) of corn grains have been distinguished and a static compression test has been carried out on an Instron 5966 testing machine. Read More

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Biomechanical Simulation of Peyronie's Disease.

Appl Bionics Biomech 2021 13;2021:6669822. Epub 2021 Mar 13.

Cervenka Consulting s.r.o., Prague, Czech Republic.

A pathological disorder of human penile function, known as Peyronie's disease, is characterized by the formation of plaque particles within the tunica albuginea. The plagues in the shape of rigid plate form in the scars as a result of the imperfect healing process. Due to high stiffness, plagues are the source of pain and anomalous deformations during erectile penis function. Read More

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Urethral support in female urinary continence part 2: a computational, biomechanical analysis of Valsalva.

Int Urogynecol J 2021 Mar 31. Epub 2021 Mar 31.

Department of Bioengineering, University of Pittsburgh, 300 O'Hara Street, 406 Benedum Hall, Pittsburgh, PA, 15260, USA.

Introduction And Hypothesis: In Part 1, we observed urethral mechanics during Valsalva that oppose current continence theories. In this study, we utilize a finite element model to elucidate the role of supportive tissues on the urethra during Valsalva. By determining the sensitivity of urethral motion and deformations to variations in tissue stiffnesses, we formulate new hypotheses regarding mechanisms of urethral passive closure. Read More

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Stiffness-tuneable nanocarriers for controlled delivery of ASC-J9 into colorectal cancer cells.

J Colloid Interface Sci 2021 Jul 18;594:513-521. Epub 2021 Mar 18.

Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S1 3JD, UK; School of Pharmacy, Changzhou University, Changzhou 213164, China. Electronic address:

Hypothesis: One of the main challenges in cancer therapy is the poor water solubility of many anticancer drugs which results in low bioavailability at the tumour sites and reduced efficacy. The currently available polymer-based anticancer drug delivery systems often suffer from low encapsulation efficiency, uncontrolled release, and lack of long-term stability. Herein, we report the development of novel stiffness-tuneable core-shell nanocarriers composed of naturally derived polymers silk fibroin (SF) and sodium alginate (SA) inside a liposomal shell for enhanced cellular uptake and controlled release of hydrophobic anticancer agent ASC-J9 (Dimethylcurcumin). Read More

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Channeling Force in the Brain: Mechanosensitive Ion Channels Choreograph Mechanics and Malignancies.

Trends Pharmacol Sci 2021 May 19;42(5):367-384. Epub 2021 Mar 19.

Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ONT, M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ONT, M5S 3E1, Canada. Electronic address:

Force is everywhere. Through cell-intrinsic activities and interactions with the microenvironment, cells generate, transmit, and sense mechanical forces, such as compression, tension, and shear stress. These forces shape the mechanical properties of cells and tissues. Read More

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