190 results match your criteria oscillating strain


Characterizing viscoelastic properties of synthetic and natural fibers and their coatings with a torsional pendulum.

Soft Matter 2021 May;17(17):4578-4593

MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.

Characterizing and understanding the viscoelastic mechanical properties of natural and synthetic fibers is of great importance in many biological and industrial applications. Microscopic techniques such as micro/nano indentation have been successfully employed in such efforts, yet these tests are often challenging to perform on fibers and come with certain limitations in the interpretation of the obtained results within the context of the macroscopic viscoelasticity in the fiber. Here we instead explore the properties of a series of natural and synthetic fibers, using a freely-oscillating torsional pendulum. Read More

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Molecular structure analysis and biological properties investigation on antiseptic drug; 2-amino-1-phenyl-1-propanol using spectroscopic and computational research analysis.

Heliyon 2021 Apr 7;7(4):e06699. Epub 2021 Apr 7.

Department of Physics, ST. Theresa's Arts and Science College, Tharangambadi, Tamilnadu, India.

The inducement of physical, chemical, structural and biological properties to entice of pharmaceutical property was analyzed by Vibrational spectroscopic, biological and theoretical tools. The structural arrangement for describing structure activity was investigated by injecting ligand groups in internal coordinate system by molecular tools (FT adopted IR, Raman, and NMR). Bond length and bond angle strain was pronounced much due to the chemical equivalent forces extension due to the injection of substitutional groups on base compound and thus non-Centro symmetry was processed. Read More

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Flexibility of microstructural adaptations in airway smooth muscle.

J Appl Physiol (1985) 2021 May 15;130(5):1555-1561. Epub 2021 Apr 15.

Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec, Canada.

The airway smooth muscle undergoes an elastic transition during a sustained contraction, characterized by a gradual decrease in hysteresivity caused by a relatively greater rate of increase in elastance than resistance. We recently demonstrated that these mechanical changes are more likely to persist after a large strain when they are acquired in dynamic versus static conditions; as if the microstructural adaptations liable for the elastic transition are more flexible when they evolve in dynamic conditions. The extent of this flexibility is undefined. Read More

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Viscoelasticity of 3D actin networks dictated by the mechanochemical characteristics of cross-linkers.

Soft Matter 2021 Mar 1. Epub 2021 Mar 1.

Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. and HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong, China.

In this study, we report a computational investigation on how the mechanochemical characteristics of crosslinking molecules influence the viscoelasticity of three dimensional F-actin networks, an issue of key interest in analyzing the behavior of living cells and biological gels. In particular, it was found that the continuous breakage and rebinding of cross-linkers result in a locally peaked loss modulus in the rheology spectrum of the network, reflecting the fact that maximum energy dissipation is achieved when the driving frequency of the applied oscillating shear becomes comparable to the dissociation/association rate of crosslinking molecules. In addition, we showed that when subjected to constant rate of shear, an actin network can exhibit either strain hardening or softening depending on the ratio between the loading rate and unbinding speed of cross-linkers. Read More

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Mice held at an environmental photic cycle oscillating at their -like period length do not show the high-fat diet-induced obesity that develops under the 24-hour photic cycle.

Chronobiol Int 2021 Apr 17;38(4):598-612. Epub 2021 Jan 17.

Laboratory of Integrative Physiology (LIP), The Department of Nutrition and Natural Products, MIGAL - Galilee Research Institute, Kiryat Shmona, Israel.

Circadian disruptions precede high-fat diet (HFD)-induced obesity (DIO). Deviation of the endogenous circadian rhythm period length () from 24 hours correlates with mice inter-strain DIO under the 24-hour light-dark cycle (T-cycle). Additionally, entrainment to a -resembling T-cycle attenuates DIO, to some extent, in muted mice. Read More

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Inducing micromechanical motion by optical excitation of a single quantum dot.

Nat Nanotechnol 2021 Mar 21;16(3):283-287. Epub 2020 Dec 21.

Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, Grenoble, France.

Hybrid quantum optomechanical systems interface a macroscopic mechanical degree of freedom with a single two-level system such as a single spin, a superconducting qubit or a single optical emitter. Recently, hybrid systems operating in the microwave domain have witnessed impressive progress. Concurrently, only a few experimental approaches have successfully addressed hybrid systems in the optical domain, demonstrating that macroscopic motion can modulate the two-level system transition energy. Read More

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Bulk modulus measurement at mHz frequencies and high-pressure using synchrotron x-ray radiation.

Rev Sci Instrum 2020 Nov;91(11):116102

Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794, USA.

We report an experimental protocol for measuring the frequency dependence of the bulk modulus carried out in a synchrotron x-ray facility based multi-anvil high-pressure apparatus. An oscillating pressure perturbation characterized by x-ray diffraction produces a volume strain measured by imaging. Together, these yield the bulk modulus of the sample. Read More

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November 2020

Bioinspired PDMS-graphene cantilever flow sensors using 3D printing and replica moulding.

Nanotechnology 2021 Feb;32(9):095501

Advanced Production Engineering, Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.

Flow sensors found in animals often feature soft and slender structures (e.g. fish neuromasts, insect hairs, mammalian stereociliary bundles, etc) that bend in response to the slightest flow disturbances in their surroundings and heighten the animal's vigilance with respect to prey and/or predators. Read More

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February 2021

Automated Conditional Screening of Multiple Strains in Parallel Adaptive Fed-Batch Cultivations.

Bioengineering (Basel) 2020 Nov 11;7(4). Epub 2020 Nov 11.

DataHow AG, ETH Zürich-HCI, F137, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland.

In bioprocess development, the host and the genetic construct for a new biomanufacturing process are selected in the early developmental stages. This decision, made at the screening scale with very limited information about the performance in larger reactors, has a major influence on the efficiency of the final process. To overcome this, scale-down approaches during screenings that show the real cell factory performance at industrial-like conditions are essential. Read More

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November 2020

Dynamic Luminal Topography: A Potential Strategy to Prevent Vascular Graft Thrombosis.

Front Bioeng Biotechnol 2020 31;8:573400. Epub 2020 Aug 31.

Division of Vascular Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, United States.

Aim: Biologic interfaces play important roles in tissue function. The vascular lumen-blood interface represents a surface where dynamic interactions between the endothelium and circulating blood cells are critical in preventing thrombosis. The arterial lumen possesses a uniform wrinkled surface determined by the underlying internal elastic lamina. Read More

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Electrospun Solid Formulation of Anaerobic Gut Microbiome Bacteria.

AAPS PharmSciTech 2020 Jul 31;21(6):214. Epub 2020 Jul 31.

Department of Organic Chemistry and Technology, Budapest University of Technology and Economics (BME), Műegyetem rakpart 3, Budapest, H-1111, Hungary.

A model anaerobic bacterium strain from the gut microbiome (Clostridium butyricum) producing anti-inflammatory molecules was incorporated into polymer-free fibers of a water-soluble cyclodextrin matrix (HP-β-CD) using a promising scaled-up nanotechnology, high-speed electrospinning. A long-term stability study was also carried out on the bacteria in the fibers. Effect of storage conditions (temperature, presence of oxygen) and growth conditions on the bacterial viability in the fibers was investigated. Read More

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Temperature changes affect the rheological properties of a silicone-based and an epoxy resin-based root canal sealers.

Aust Endod J 2020 Dec 29;46(3):394-399. Epub 2020 Jul 29.

Department of Dentistry, Universidade da Região de Joinville - Univille, Joinville, Brazil.

To evaluate temperature changes on the rheological properties (setting time and complex viscosity (η*)) of GuttaFlow Bioseal (GFB) and AH Plus Jet (AHPJ). Rheological measurements were performed in oscillating mode at the strain amplitude and angular frequency of 0.01% and 10 rad s , respectively. Read More

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December 2020

Deep Learning Enabled Strain Mapping of Single-Atom Defects in Two-Dimensional Transition Metal Dichalcogenides with Sub-Picometer Precision.

Nano Lett 2020 May 16;20(5):3369-3377. Epub 2020 Apr 16.

Department of Materials Science and Engineering, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States.

Two-dimensional (2D) materials offer an ideal platform to study the strain fields induced by individual atomic defects, yet challenges associated with radiation damage have so far limited electron microscopy methods to probe these atomic-scale strain fields. Here, we demonstrate an approach to probe single-atom defects with sub-picometer precision in a monolayer 2D transition metal dichalcogenide, WSeTe. We utilize deep learning to mine large data sets of aberration-corrected scanning transmission electron microscopy images to locate and classify point defects. Read More

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Somite Division and New Boundary Formation by Mechanical Strain.

iScience 2020 Apr 13;23(4):100976. Epub 2020 Mar 13.

Department of Orthopaedic Surgery, Amsterdam University Medical Centres, Amsterdam Movement Sciences, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands; Department of Medical Biology, Amsterdam University Medical Centres, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands. Electronic address:

Somitogenesis, the primary segmentation of the vertebrate embryo, is associated with oscillating genes that interact with a wave of cell differentiation. The necessity of cell-matrix adherence and embryonic tension, however, suggests that mechanical cues are also involved. To explicitly investigate this, we applied surplus axial strain to live chick embryos. Read More

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Coherent electrical control of a single high-spin nucleus in silicon.

Nature 2020 03 11;579(7798):205-209. Epub 2020 Mar 11.

Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney, New South Wales, Australia.

Nuclear spins are highly coherent quantum objects. In large ensembles, their control and detection via magnetic resonance is widely exploited, for example, in chemistry, medicine, materials science and mining. Nuclear spins also featured in early proposals for solid-state quantum computers and demonstrations of quantum search and factoring algorithms. Read More

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Strain Modulated Superlattices in Graphene.

Nano Lett 2020 May 11;20(5):3113-3121. Epub 2020 Mar 11.

Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.

Numerous theoretically proposed devices and novel phenomena have sought to take advantage of the intense pseudogauge fields that can arise in strained graphene. Many of these proposals, however, require fields to oscillate with a spatial frequency smaller than the magnetic length, while to date only the generation and effects of fields varying at a much larger length scale have been reported. Here, we describe the creation of short wavelength, periodic pseudogauge-fields using rippled graphene under extreme (>10%) strain and study of its effects on Dirac electrons. Read More

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Quantum Hall Response to Time-Dependent Strain Gradients in Graphene.

Phys Rev Lett 2020 Jan;124(2):026602

Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, IL-69978 Tel Aviv, Israel.

Mechanical deformations of graphene induce a term in the Dirac Hamiltonian that is reminiscent of an electromagnetic vector potential. Strain gradients along particular lattice directions induce local pseudomagnetic fields and substantial energy gaps as indeed observed experimentally. Expanding this analogy, we propose to complement the pseudomagnetic field by a pseudoelectric field, generated by a time-dependent oscillating stress applied to a graphene ribbon. Read More

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January 2020

Airway smooth muscle adapting in dynamic conditions is refractory to the bronchodilator effect of a deep inspiration.

Am J Physiol Lung Cell Mol Physiol 2020 02 8;318(2):L452-L458. Epub 2020 Jan 8.

Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Quebec City, Quebec, Canada.

Airway smooth muscle (ASM) is continuously strained during breathing at tidal volume. Whether this tidal strain influences the magnitude of the bronchodilator response to a deep inspiration (DI) is not clearly defined. The present in vitro study examines the effect of tidal strain on the bronchodilator effect of DIs. Read More

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February 2020

Structural and Hemodynamic Analyses of Different Stent Structures in Curved and Stenotic Coronary Artery.

Front Bioeng Biotechnol 2019 6;7:366. Epub 2019 Dec 6.

Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing, China.

Coronary artery stenting is commonly used for the treatment of coronary stenosis, and different stent structures indeed have various impacts on the stress distribution within the plaque and artery as well as the local hemodynamic environment. This study aims to evaluate the performance of different stent structures by characterizing the mechanical parameters after coronary stenting. Six stent structures including three commercially-shaped stents (Palmaz-Schatz-shaped, Xience Prime-shaped, and Cypher-shaped) and three author-developed stents (C-Rlink, C-Rcrown, and C-Astrut) implanted into a curved stenotic coronary artery were investigated. Read More

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December 2019

Do Contaminating Substances Influence the Rheological Properties of Root Canal Sealers?

J Endod 2020 Feb 6;46(2):258-263. Epub 2019 Dec 6.

Department of Dentistry, Universidade Positivo, Curitiba, Paraná, Brazil. Electronic address:

Introduction: This study evaluated the effect of residual substances derived from irrigant solutions and intracanal medications on the rheological properties of a silicone, gutta-percha, and bioactive glass-based sealer in comparison with an epoxy resin-based sealer.

Methods: Thin films of contaminants (0.5 μL) (3% sodium hypochlorite [NaOCl], chlorhexidine digluconate [CHX], 17% EDTA, calcium hydroxide, 40% citric acid, or distilled water [DW]) were applied along with freshly mixed GuttaFlow Bioseal (GFB; Coltene/Whaledent, Langenau, Germany) or AH Plus Jet (Dentsply DeTrey, Konstanz, Germany) on the lower plate of a dynamic rheometer. Read More

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February 2020

Amplitude Dependence of Resonance Frequency and its Consequences for Scanning Probe Microscopy.

Sensors (Basel) 2019 Oct 17;19(20). Epub 2019 Oct 17.

Department of Physics, McGill University, Montreal, QC H3A 2T8, Canada.

With recent advances in scanning probe microscopy (SPM), it is now routine to determine the atomic structure of surfaces and molecules while quantifying the local tip-sample interaction potentials. Such quantitative experiments using noncontact frequency modulation atomic force microscopy is based on the accurate measurement of the resonance frequency shift due to the tip-sample interaction. Here, we experimentally show that the resonance frequency of oscillating probes used for SPM experiments change systematically as a function of oscillation amplitude under typical operating conditions. Read More

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October 2019

Stretching-Driven Crystal Anisotropy and Optical Modulations of Flexible Wide Band Gap Inorganic Thin Films.

ACS Appl Mater Interfaces 2019 Nov 25;11(44):41516-41522. Epub 2019 Oct 25.

Department of Materials Science and Engineering , Yonsei University , Seoul 03722 , Korea.

Strain engineering has been extensively explored for tailoring the material properties and, in turn, improving the device performance of semiconducting thin films. In particular, the effects of strain on the optical properties of these films have attracted considerable research interest, but experimental demonstrations in flexible systems have rarely been reported. Here, we exploited the variable optical properties of flexible ZnS thin films by imposing a controllable external compressive stress during a stretching-driven deposition process. Read More

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November 2019

Relaxation Behavior and Nonlinear Surface Rheology of PEO-PPO-PEO Triblock Copolymers at the Air-Water Interface.

Langmuir 2019 Nov 22;35(44):14388-14396. Epub 2019 Oct 22.

Food Physics Group , Wageningen University , Bornse Weilanden 9 , 6708 WG Wageningen , The Netherlands.

Surface dilatational viscoelasticity of adsorbed layers of pluronics triblock copolymers at the air-water interface was measured using the oscillating barrier technique. The effect of molecular architecture and concentration on surface viscoelasticity was explored for two different types of pluronics with different degrees of hydrophobicity, Pluronic F-108 ( ≈ 14 600 g/mol) and Pluronic P-123 ( ≈ 5800 g/mol), the former exhibiting a larger hydrophilic to hydrophobic block length ratio. Frequency sweeps in the linear regime suggested that interfacial films of F-108 have higher surface limiting elasticity and larger in-plane and out-of-plane relaxation times at the same bulk concentration (the former possibly related to in-plane microstructure rearrangements, the latter to surface/bulk diffusion). Read More

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November 2019

Shortening of airway smooth muscle is modulated by prolonging the time without simulated deep inspirations in ovine tracheal strips.

J Appl Physiol (1985) 2019 12 23;127(6):1528-1538. Epub 2019 Sep 23.

Laval University, Quebec, Canada.

The shortening of airway smooth muscle (ASM) is greatly affected by time. This is because stimuli affecting ASM shortening, such as bronchoactive molecules or the strain inflicted by breathing maneuvers, not only alter quick biochemical processes regulating contraction but also slower processes that allow ASM to adapt to an ever-changing length. Little attention has been given to the effect of time on ASM shortening. Read More

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December 2019

Fiber Bragg grating sensor interrogation system based on an optoelectronic oscillator loop.

Opt Express 2019 Aug;27(16):23274-23281

In this article, we propose and experimentally demonstrate a fiber Bragg grating (FBG) sensor interrogation technique based on an optoelectronic oscillator (OEO). The main components of the OEO loop in this proposed scheme contains an electro-optic modulator (EOM), a section of dispersive element, an electric filter, and a photodiode (PD). The reflection signal of the FBG sensor is functioning as the optical source of the OEO. Read More

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Biomechanical Comparison of Fixed- versus Variable-Angle Locking Screws for Distal Humerus Comminuted Fractures.

Clin Orthop Surg 2019 Sep 12;11(3):302-308. Epub 2019 Aug 12.

Department of Orthopedics, The Hand and Upper Extremity Center of Georgia, Atlanta, GA, USA.

Background: To compare the stability of fixed- versus variable-angle locking constructs for the comminuted distal humerus fracture (AO/OTA 13-A3).

Methods: Eight pairs of complete humeri harvested from eight fresh frozen cadavers were used for the study. We fixed the intact humeri using 2. Read More

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September 2019

AC elastocaloric effect as a probe for thermodynamic signatures of continuous phase transitions.

Rev Sci Instrum 2019 Aug;90(8):083902

Geballe Laboratory for Advanced Materials, Stanford University, 476 Lomita Mall, Stanford, California 94305, USA.

Studying the response of materials to strain can elucidate subtle properties of the electronic structure in strongly correlated materials. Here, we focus on the elastocaloric coefficients, forming a second rank tensor quantity describing the relation between entropy and strain. In contrast to the better-known elastoresistivity, the elastocaloric effect is a thermodynamic quantity. Read More

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Searching for Ultralight Dark Matter with Optical Cavities.

Phys Rev Lett 2019 Jul;123(3):031304

Department of Physics, University of Nevada, Reno, Nevada 89557, USA.

We discuss the use of optical cavities as tools to search for dark matter (DM) composed of virialized ultralight fields (VULFs). Such fields could lead to oscillating fundamental constants, resulting in oscillations of the length of rigid bodies. We propose searching for these effects via differential strain measurement of rigid and suspended-mirror cavities. Read More

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Loss of flow responsive Tie1 results in Impaired
Aortic valve remodeling.

Dev Biol 2019 11 15;455(1):73-84. Epub 2019 Jul 15.

Division of Pediatrics Cardiology, Vanderbilt University, Nashville, TN, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN, USA. Electronic address:

The mechanisms regulating endothelial cell response to hemodynamic forces required for heart valve development, especially valve remodeling, remain elusive. Tie1, an endothelial specific receptor tyrosine kinase, is up-regulated by oscillating shear stress and is required for lymphatic valve development. In this study, we demonstrate that valvular endothelial Tie1 is differentially expressed in a dynamic pattern predicted by disturbed flow during valve remodeling. Read More

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November 2019

Structural origin for vibration-induced accelerated aging and rejuvenation in metallic glasses.

J Chem Phys 2019 May;150(20):204507

Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China.

Glassy materials are nonequilibrium and their energy states have crucial influences on properties. Recent studies have shown that oscillating deformations (vibrations) can cause either accelerated aging (lowering energy) or rejuvenation (elevating energy); however, the underlying atomic mechanisms remain elusive. Using metallic glasses (MGs) as model systems, we show that the vibration-induced accelerated aging is correlated with the strain field of the stringlike atomic motions stemming from the Johari-Goldstein (β) relaxation, whereas the rejuvenation is associated with nonlinear response and the formation of nanoscale shear bands attributing to the activation of α relaxation. Read More

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