2,061 results match your criteria external shear

Ultrasound and shear-wave elastography characteristics of the iliocapsularis muscle in pincer-type femoroacetabular impingement.

PM R 2021 Sep 23. Epub 2021 Sep 23.

Department of Ultrasound, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, PR China.

Introduction: The iliocapsularis muscle is a structure of the anterior hip, which may play a key role in stabilizing the hip joint; but no studies exist describing ultrasound (US) and shear-wave characteristics of this muscle.

Objectives: To investigate the anatomic dimensions and elasticity of the iliocapsularis muscle in patients with pincer-type femoroacetabular impingement (FAI) and normal hips using gray-scale US and shear-wave elastography (SWE).

Design: Case-control study. Read More

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September 2021

Analysis on vertical-pitch coupled dynamics characteristics of shearer with corrected load.

Sci Rep 2021 Sep 20;11(1):18659. Epub 2021 Sep 20.

Fuxin City Industrial Technology Research Institute, Fuxin, 123000, Liaoning, China.

With regard to the severe vertical and pitching vibration of shearer in actual working conditions, the vertical-pitch coupled dynamics model of shearer with 13 degrees of freedom was established using multi-body dynamics theory. Based on the elasticity theory, Hertz contact and collision dynamics, the connection stiffness model of shear body and the traction section, the rocker arm with clearance and the traction section, the support stiffness models for the guide shoe and the smooth shoe, and the stiffness characteristics model of the rocker arm were constructed respectively. Taking into account the convergence of solution process and the reliability of results, a modified drum load was proposed as the external excitation of the system and the dynamic characteristics of key parts of shearer under different working conditions were analyzed. Read More

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September 2021

Hemodynamic Responses in Carotid Bifurcation Induced by Enhanced External Counterpulsation Stimulation in Healthy Controls and Patients With Neurological Disorders.

Front Physiol 2021 31;12:717080. Epub 2021 Aug 31.

Department of Cardiology, The Eighth Affiliated Hospital of Sun Yat-sen University, Shenzhen, China.

Enhanced external counterpulsation is a Food and Drug Administration-approved, non-invasive, assisted circulation therapy for ischemic cardiovascular and cerebrovascular diseases. Previous studies have confirmed that EECP stimulation induces largely different cerebral hemodynamic responses in patients with ischemic stroke and healthy controls. However, the underlying mechanisms remain uncertain. Read More

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Numerical simulation of the transport of nanoparticles as drug carriers in hydromagnetic blood flow through a diseased artery with vessel wall permeability and rheological effects.

Microvasc Res 2021 Sep 8;139:104241. Epub 2021 Sep 8.

Department of Aeronautics and Astronautics, Air Force Institute of Technology, Wright Patterson Air Force Base, Dayton, OH 45433, USA.

The present study considers the mathematical modeling of unsteady non-Newtonian hydro-magnetic nano-hemodynamics through a rigid cylindrical artery featuring two different stenoses (composite and irregular). The Ostwald-De Waele power-law fluid model is adopted to simulate the non-Newtonian characteristics of blood. Inspired by drug delivery applications for cardiovascular treatments, blood is considered doped with a homogenous suspension of biocompatible nanoparticles. Read More

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September 2021

Glenoid labrum articular disruption in a six-year-old child: A case report.

Trauma Case Rep 2021 Oct 26;35:100527. Epub 2021 Aug 26.

Department of Orthopedic Surgery and Traumatology, Kafr el-sheikh University, Egypt.

Introduction: Traumatic anterior shoulder instability is a rare occurrence in the childhood. While glenoid labrum articular disruption itself is an uncommon condition that accompanies shoulder instability in the contact athletes, the occurrence of such lesion in a child is of extreme rarity. To the best of our knowledge, this case is the first to be reported at such a young age. Read More

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October 2021

Local Piezoelectric Properties of Doped Biomolecular Crystals.

Materials (Basel) 2021 Aug 30;14(17). Epub 2021 Aug 30.

Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Herzl St 234, Rehovot 7610001, Israel.

Piezoelectricity is the ability of certain crystals to generate mechanical strain proportional to an external electric field. Though many biomolecular crystals contain polar molecules, they are frequently centrosymmetric, signifying that the dipole moments of constituent molecules cancel each other. However, piezoelectricity can be induced by stereospecific doping leading to symmetry reduction. Read More

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An In Vivo Data-Based Computational Study on Sitting-Induced Hemodynamic Changes in the External Iliac Artery.

J Biomech Eng 2022 Feb;144(2)

State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.

Although sedentary behavior (characterized by prolonged sitting without otherwise being active in daily life) is widely regarded as a risk factor for peripheral artery disease (PAD), underlying biomechanical mechanisms remain insufficiently understood. In this study, geometrical models of ten external iliac arteries were reconstructed based on angiographic data acquired from five healthy young subjects resting in supine and sitting (mimicked by side lying with bent legs) positions, respectively, which were further combined with measured blood flow velocity waveforms in the common iliac arteries (with each body posture being maintained for 30 min) to build computational models for simulating intra-arterial hemodynamics. Morphological analyses showed that the external iliac arteries suffered from evident bending deformation upon the switch of body posture from supine to sitting. Read More

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February 2022

Forward-viewing estimation of 3D blood flow velocity fields by intravascular ultrasound: Influence of the catheter on velocity estimation in stenoses.

Ultrasonics 2021 Dec 23;117:106558. Epub 2021 Aug 23.

Georgia Institute of Technology, Interdisciplinary BioEngineering Graduate Program, 315 Ferst Dr., Atlanta, GA 30332, USA; Georgia Institute of Technology and Emory University, Wallace H. Coulter Department of Biomedical Engineering, 313 Ferst Dr NW, Atlanta, GA 30332, USA. Electronic address:

Coronary artery disease is the most common type of cardiovascular disease, affecting > 18 million adults, and is responsible for > 365 k deaths per year in the U.S. alone. Read More

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December 2021

Modeling of the Human Bone Environment: Mechanical Stimuli Guide Mesenchymal Stem Cell-Extracellular Matrix Interactions.

Materials (Basel) 2021 Aug 7;14(16). Epub 2021 Aug 7.

IZKF Group Tissue Regeneration in Musculoskeletal Diseases, University Hospital Wuerzburg, 97070 Wuerzburg, Germany.

In bone tissue engineering, the design of in vitro models able to recreate both the chemical composition, the structural architecture, and the overall mechanical environment of the native tissue is still often neglected. In this study, we apply a bioreactor system where human bone-marrow hMSCs are seeded in human femoral head-derived decellularized bone scaffolds and subjected to dynamic culture, i.e. Read More

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Homogeneity and Viscoelastic Behaviour of Bitumen Film in Asphalt Mixtures Containing RAP.

Materials (Basel) 2021 Aug 4;14(16). Epub 2021 Aug 4.

Road Construction Technology Department, Faculty of Civil Engineering, Warsaw University of Technology, 00-637 Warsaw, Poland.

This article discusses the phenomenon of fresh and RAP binders miscibility and presents test results of bitumen film properties from specially prepared asphalt mixtures. The miscibility of a fresh binder and a RAP binder still has not been fully recognised. The aim of this study was to determine the homogeneity level of the bitumen film based on viscoelastic assessment. Read More

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Effect of Anisotropy of Potassium Dihydrogen Phosphate Crystals on Its Deformation Mechanisms Subjected to Nanoindentation.

ACS Appl Mater Interfaces 2021 Sep 23;13(34):41351-41360. Epub 2021 Aug 23.

Laboratory for Precision and Nano Processing Technologies, School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia.

Potassium dihydrogen phosphate (KDP) is an important nonlinear material due to its excellent physical and optical properties. However, it is also a difficult-to-machine material due to its complex anisotropic microstructure. To better understand the deformation mechanisms under external stresses, this paper aims to carry out systematic nanoindentation simulations using molecular dynamics (MD). Read More

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September 2021

Effects of compressive lesions on intraoperative human spinal cord elasticity.

J Neurosurg Spine 2021 Aug 20:1-10. Epub 2021 Aug 20.

1Division of Neurosurgery, Department of Surgery, College of Medicine.

Objective: Although evaluating tissue elasticity has various clinical applications, spinal cord elasticity (SCE) in humans has never been well documented. In this study, the authors aimed to evaluate the impact of compression on human SCE in vivo.

Methods: The authors prospectively assessed SCE using intraoperative shear wave elastography (SWE). Read More

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Distal Radius Fractures and the Dorsal Spanning Plate in the Management of the Polytraumatized Patient.

J Orthop Trauma 2021 Sep;35(Suppl 3):s6-s10

Department of Orthopaedic Surgery, UT Southwestern Medical Center, Dallas, TX.

Summary: Distal radius fractures are some of the most common fractures treated by the orthopaedic surgeon. There are a variety of methods of fixation to treat these fractures; however, in patients with polytrauma and in high-energy fracture patterns, fixation options can be limited. In the past, these fractures were treated with plaster, Kirschner wires, or external fixators that were fraught with complications. Read More

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September 2021

Nonlinear Characterization of Tissue Viscoelasticity with Acoustoelastic Attenuation of Shear Waves.

IEEE Trans Ultrason Ferroelectr Freq Control 2021 Aug 16;PP. Epub 2021 Aug 16.

Shear-wave elastography (SWE) measures shear-wave speed (SWS), which is related to the underlying shear modulus of soft tissue. SWS in soft tissue changes depending on the amount of the external strain that soft tissue is subjected to due to the acoustoelastic (AE) phenomenon. In the literature, variations of SWS as a function of applied uniaxial strain were used for nonlinear characterization, assuming soft tissues to be elastic, although soft tissues are indeed viscoelastic in nature. Read More

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Light-Responsive Dynamic Protein Hydrogels Based on LOVTRAP.

Langmuir 2021 08 15;37(33):10214-10222. Epub 2021 Aug 15.

Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.

Protein-based hydrogels can mimic many aspects of native extracellular matrices (ECMs) and are promising biomedical materials that find various applications in cell proliferation, drug/cell delivery, and tissue engineering. To be adapted for different tasks, it is important that the mechanical and/or biochemical properties of protein-based hydrogels can be regulated by external stimuli. Light as a regulation stimulus is of advantage because it can be easily applied in demanded spatiotemporal manners. Read More

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Noninvasive Detection of Intracranial Hypertension by Novel Ultrasound Time-Harmonic Elastography.

Invest Radiol 2021 Aug 9. Epub 2021 Aug 9.

From the Institute of Medical Informatics Department of Radiology Department of Neurology, Charité-Universitätsmedizin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Objective: A method for measuring intracranial pressure (ICP) noninvasively has long been sought after in neurology and neurosurgery. Treatment failure in individuals presenting with unspecific symptoms such as headache, gait disturbance, or visual impairment occurring in response to increased ICP can lead to irreversible brain injury, progressive disability, and death. Guidelines for diagnostic ICP measurement recommend intracranial placement of pressure tip catheters or lumbar puncture (LP) despite their invasiveness and possible complications. Read More

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Breast Cancer Detection using Multimodal Time Series Features from Ultrasound Shear Wave Absolute Vibro-Elastography.

IEEE J Biomed Health Inform 2021 Aug 10;PP. Epub 2021 Aug 10.

In shear wave absolute vibro-elastography (S-WAVE), a steady-state multi-frequency external mechanical excitation is applied to tissue, while a time-series of ultrasound radio-frequency (RF) data are acquired. Our objective is to determine the potential of S-WAVE to classify breast tissue lesions as malignant or benign. We present a new processing pipeline for feature-based classification of breast cancer using S-WAVE data, and we evaluate it on a new data set collected from 40 patients. Read More

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Bending and Shear Behaviour of Waste Rubber Concrete-Filled FRP Tubes with External Flanges.

Polymers (Basel) 2021 Jul 29;13(15). Epub 2021 Jul 29.

University of Southern Queensland, Centre for Future Materials (CFM), Toowoomba, QLD 4350, Australia.

An innovative beam concept made from hollow FRP tube with external flanges and filled with crumbed rubber concrete was investigated with respect to bending and shear. The performance of the rubberised-concrete-filled specimens was then compared with hollow and normal-concrete-filled tubes. A comparison between flanged and non-flanged hollow and concrete-filled tubes was also implemented. Read More

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Residual stress and osmotic swelling of the periodontal ligament.

Biomech Model Mechanobiol 2021 Aug 7. Epub 2021 Aug 7.

Department of Biomedical Engineering, University of Minnesota-Twin Cities, Minneapolis, USA.

Osmotic swelling and residual stress are increasingly recognized as important factors in soft tissue biomechanics. Little attention has been given to residual stress in periodontal ligament (PDL) biomechanics despite its rapid growth and remodeling potential. Those tissues that bear compressive loads, e. Read More

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Regulating Tissue-Mimetic Mechanical Properties of Bottlebrush Elastomers by Magnetic Field.

ACS Appl Mater Interfaces 2021 Aug 4;13(32):38783-38791. Epub 2021 Aug 4.

Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russian Federation.

We report on a new class of magnetoactive elastomers (MAEs) based on bottlebrush polymer networks filled with carbonyl iron microparticles. By synergistically combining solvent-free, yet supersoft polymer matrices, with magnetic microparticles, we enable the design of composites that not only mimic the mechanical behavior of various biological tissues but also permit contactless regulation of this behavior by external magnetic fields. While the bottlebrush architecture allows to finely tune the matrix elastic modulus and strain-stiffening, the magnetically aligned microparticles generate a 3-order increase in shear modulus accompanied by a switch from a viscoelastic to elastic regime as evidenced by a ca. Read More

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Rolling controls sperm navigation in response to the dynamic rheological properties of the environment.

Elife 2021 08 4;10. Epub 2021 Aug 4.

Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, United States.

Mammalian sperm rolling around their longitudinal axes is a long-observed component of motility, but its function in the fertilization process, and more specifically in sperm migration within the female reproductive tract, remains elusive. While investigating bovine sperm motion under simple shear flow and in a quiescent microfluidic reservoir and developing theoretical and computational models, we found that rolling regulates sperm navigation in response to the rheological properties of the sperm environment. In other words, rolling enables a sperm to swim progressively even if the flagellum beats asymmetrically. Read More

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Ciliary chemosensitivity is enhanced by cilium geometry and motility.

Elife 2021 08 4;10. Epub 2021 Aug 4.

Max Planck Institute for Dynamics and Self-Organization (MPIDS), Göttingen, Germany.

Cilia are hairlike organelles involved in both sensory functions and motility. We discuss the question of whether the location of chemical receptors on cilia provides an advantage in terms of sensitivity and whether motile sensory cilia have a further advantage. Using a simple advection-diffusion model, we compute the capture rates of diffusive molecules on a cilium. Read More

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Stress distribution in the walls of major arteries: implications for atherogenesis.

Quant Imaging Med Surg 2021 Aug;11(8):3494-3505

School of Public Health, Faculty of Health Sciences, Curtin University, Nedlands, WA, Australia.

Background: There is a correlation between the sites of atheroma development and stress points in the arterial system. Generally, pulse pressure results in stresses acting on the vascular vessel, including longitudinal stress, radial or normal stress, tangential stress or hoop stress and shear stress. This paper explores the relationship between arterial wall shear stress and pulsatile blood pressure with the aim of furthering the understanding of atherogenesis and plaque progression. Read More

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Hydrodynamic stress and phenotypic plasticity of the zebrafish regenerating fin.

J Exp Biol 2021 Aug 2;224(15). Epub 2021 Aug 2.

Department of Biology, University of Fribourg, Chemin du Musée 10, 1700 Fribourg, Switzerland.

Understanding how extrinsic factors modulate genetically encoded information to produce a specific phenotype is of prime scientific interest. In particular, the feedback mechanism between abiotic forces and locomotory organs during morphogenesis to achieve efficient movement is a highly relevant example of such modulation. The study of this developmental process can provide unique insights on the transduction of cues at the interface between physics and biology. Read More

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Identification of microRNAs responsive to shear loading in rat skin.

Int Wound J 2021 Jul 31. Epub 2021 Jul 31.

Department of Gerontological Nursing/Wound Care Management, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.

Pressure injuries (PIs) are localised skin injuries that result from pressure with or without shear force. Shear force is more destructive than pressure in clinical settings. Therefore, determining the critical external forces is important for selecting the appropriate care to prevent PIs. Read More

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High shear stress enhances endothelial permeability in the presence of the risk haplotype at 9p21.3.

APL Bioeng 2021 Sep 26;5(3):036102. Epub 2021 Jul 26.

Department of Neuroscience, The Scripps Research Institute, La Jolla, California 92037, USA.

Single nucleotide polymorphisms (SNPs) are exceedingly common in non-coding loci, and while they are significantly associated with a myriad of diseases, their specific impact on cellular dysfunction remains unclear. Here, we show that when exposed to external stressors, the presence of risk SNPs in the 9p21.3 coronary artery disease (CAD) risk locus increases endothelial monolayer and microvessel dysfunction. Read More

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September 2021

Mechanochromic, Structurally Colored, and Edible Hydrogels Prepared from Hydroxypropyl Cellulose and Gelatin.

Adv Mater 2021 Sep 29;33(37):e2102112. Epub 2021 Jul 29.

Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.

Hydroxypropyl cellulose (HPC) is an edible, cost-effective and widely used derivative of cellulose. Under lyotropic conditions in water, HPC forms a photonic, liquid crystalline mesophase with an exceptional mechanochromic response. However, due to insufficient physical cross-linking photonic HPC can flow freely as a viscous liquid, preventing the exploitation of this mechanochromic material in the absence of any external encapsulation or structural confinement. Read More

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September 2021

Field-Induced Transversely Isotropic Shear Response of Ellipsoidal Magnetoactive Elastomers.

Materials (Basel) 2021 Jul 15;14(14). Epub 2021 Jul 15.

Leibniz Institute of Polymer Research Dresden e. V., Hohe Strasse 6, 01069 Dresden, Germany.

Magnetoactive elastomers (MAEs) claim a vital place in the class of field-controllable materials due to their tunable stiffness and the ability to change their macroscopic shape in the presence of an external magnetic field. In the present work, three principal geometries of shear deformation were investigated with respect to the applied magnetic field. The physical model that considers dipole-dipole interactions between magnetized particles was used to study the stress-strain behavior of ellipsoidal MAEs. Read More

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Flow pumping by external periodic shear applied to a soft interface.

Sci Rep 2021 Jul 22;11(1):15041. Epub 2021 Jul 22.

Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45137-66731, Iran.

Flow pumping in viscous fluids is of prime importance in micro-fluidic applications. Here we show that a single colloidal particle in front of a soft wall, manipulated by external means like an optical tweezer, can pump the ambient viscous fluid. The particle, moving back and forth parallel to the soft wall, can produce an averaged net flow in a direction perpendicular to the wall. Read More

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Exploring lumbar and lower limb kinematics and kinetics for evidence that lifting technique is associated with LBP.

PLoS One 2021 21;16(7):e0254241. Epub 2021 Jul 21.

Curtin School of Allied Health, Curtin University, Perth, Western Australia, Australia.

Purpose: To investigate if lumbar and lower limb kinematics or kinetics are different between groups with and without a history of LBP during lifting. Secondly, to investigate relationships between biomechanical variables and pain ramp during repeated lifting.

Methods: 21 LBP and 20 noLBP participants completed a 100-lift task, where lumbar and lower limb kinematics and kinetics were measured during lifting, with a simultaneous report of LBP intensity every 10 lifts. Read More

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