4,189 results match your criteria elastic transition

A stochastic micro to macro mechanical model for the evolution of bone-implant interface stiffness.

Acta Biomater 2021 Jun 12. Epub 2021 Jun 12.

Department of Biomaterials, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.

Upon placement of an implant into living bone, an interface is formed through which various biochemical, biological, physical and mechanical processes and interactions take place. This interface evolves over time as the mechanical properties of peri-implant bone increase. Owing to the multifactorial nature of interfacial processes, it is challenging to devise a comprehensive model for predicting the mechanical behavior of the bone-implant interface. Read More

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Ultrahigh energy-dissipation elastomers by precisely tailoring the relaxation of confined polymer fluids.

Nat Commun 2021 Jun 14;12(1):3610. Epub 2021 Jun 14.

Key Laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry, Beihang University, Beijing, P. R. China.

Energy-dissipation elastomers relying on their viscoelastic behavior of chain segments in the glass transition region can effectively suppress vibrations and noises in various fields, yet the operating frequency of those elastomers is difficult to control precisely and its range is narrow. Here, we report a synergistic strategy for constructing polymer-fluid-gels that provide controllable ultrahigh energy dissipation over a broad frequency range, which is difficult by traditional means. This is realized by precisely tailoring the relaxation of confined polymer fluids in the elastic networks. Read More

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Yielding in an Integer Automaton Model for Amorphous Solids under Cyclic Shear.

Phys Rev Lett 2021 May;126(21):218005

Northeastern University, Boston, Massachusetts 02115, USA.

We present results on an automaton model of an amorphous solid under cyclic shear. After a transient, the steady state falls into one of three cases in order of increasing strain amplitude: (i) pure elastic behavior with no plastic activity, (ii) limit cycles where the state recurs after an integer period of strain cycles, and (iii) irreversible plasticity with longtime diffusion. The number of cycles N required for the system to reach a periodic orbit diverges as the amplitude approaches the yielding transition between regimes (ii) and (iii) from below, while the effective diffusivity D of the plastic strain field vanishes on approach from above. Read More

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Effect of cellular rearrangement time delays on the rheology of vertex models for confluent tissues.

PLoS Comput Biol 2021 Jun 7;17(6):e1009049. Epub 2021 Jun 7.

Department of Physics, Syracuse University, Syracuse, New York, United States of America.

Large-scale tissue deformation during biological processes such as morphogenesis requires cellular rearrangements. The simplest rearrangement in confluent cellular monolayers involves neighbor exchanges among four cells, called a T1 transition, in analogy to foams. But unlike foams, cells must execute a sequence of molecular processes, such as endocytosis of adhesion molecules, to complete a T1 transition. Read More

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Triblock polyester thermoplastic elastomers with semi-aromatic polymer end blocks by ring-opening copolymerization.

Chem Sci 2020 May 4;11(25):6567-6581. Epub 2020 May 4.

Oxford Chemistry, Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK

Thermoplastic elastomers benefit from high elasticity and straightforward (re)processability; they are widely used across a multitude of sectors. Currently, the majority derive from oil, do not degrade or undergo chemical recycling. Here a new series of ABA triblock polyesters are synthesized and show high-performances as degradable thermoplastic elastomers; their composition is poly(cyclohexene--phthalate)--poly(ε-decalactone)--poly(cyclohexene--phthalate) {PE-PDL-PE}. Read More

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Contributions of the Endothelium to Vascular Calcification.

Front Cell Dev Biol 2021 17;9:620882. Epub 2021 May 17.

Division of Cardiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States.

Vascular calcification (VC) increases morbidity and mortality and constitutes a significant obstacle during percutaneous interventions and surgeries. On a cellular and molecular level, VC is a highly regulated process that involves abnormal cell transitions and osteogenic differentiation, re-purposing of signaling pathways normally used in bone, and even formation of osteoclast-like cells. Endothelial cells have been shown to contribute to VC through a variety of means. Read More

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Estrogen Modulates Epithelial Breast Cancer Cell Mechanics and Cell-to-Cell Contacts.

Materials (Basel) 2021 May 28;14(11). Epub 2021 May 28.

Institute for Biophysics, Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria.

Excessive estrogen exposure is connected with increased risk of breast cancer and has been shown to promote epithelial-mesenchymal-transition. Malignant cancer cells accumulate changes in cell mechanical and biochemical properties, often leading to cell softening. In this work we have employed atomic force microscopy to probe the influence of estrogen on the viscoelastic properties of MCF-7 breast cancer cells cultured either in normal or hormone free-medium. Read More

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About the Role of Interfaces on the Fatigue Crack Propagation in Laminated Metallic Composites.

Materials (Basel) 2021 May 14;14(10). Epub 2021 May 14.

Materials Science & Engineering, Institute I, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstr. 5, 91058 Erlangen, Germany.

The influence of gradients in hardness and elastic properties at interfaces of dissimilar materials in laminated metallic composites (LMCs) on fatigue crack propagation is investigated experimentally for three different LMC systems: Al/Al-LMCs with dissimilar yield stress and Al/Steel-LMCs as well as Al/Ti/Steel-LMCs with dissimilar yield stress and Young's modulus, respectively. The damage tolerant fatigue behavior in Al/Al-LMCs with an alternating layer structure is enhanced significantly compared to constituent monolithic materials. The prevalent toughening mechanisms at the interfaces are identified by microscopical methods and synchrotron X-ray computed tomography. Read More

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Critical Dynamics of Defects and Mechanisms of Damage-Failure Transitions in Fatigue.

Materials (Basel) 2021 May 14;14(10). Epub 2021 May 14.

Institute of Continuous Media Mechanics of the Ural Branch, RAS, 614013 Perm, Russia.

An experimental methodology was developed for estimating a very high cycle fatigue (VHCF) life of the aluminum alloy AMG-6 subjected to preliminary deformation. The analysis of fatigue damage staging is based on the measurement of elastic modulus decrement according to "in situ" data of nonlinear dynamics of free-end specimen vibrations at the VHCF test. The correlation of fatigue damage staging and fracture surface morphology was studied to establish the scaling properties and kinetic equations for damage localization, "fish-eye" nucleation, and transition to the Paris crack kinetics. Read More

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A Fully Coupled Simulation of Planar Deposition Flow and Fiber Orientation in Polymer Composites Additive Manufacturing.

Materials (Basel) 2021 May 16;14(10). Epub 2021 May 16.

Department of Mechanical Engineering, School of Engineering and Computer Science, Baylor University, Waco, TX 76798, USA.

Numerical studies for polymer composites deposition additive manufacturing have provided significant insight promoting the rapid development of the technology. However, little of existing literature addresses the complex yet important polymer composite melt flow-fiber orientation coupling during deposition. This paper explores the effect of flow-fiber interaction for polymer deposition of 13 wt. Read More

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Molecular Dynamics Simulation for the Effect of Fluorinated Graphene Oxide Layer Spacing on the Thermal and Mechanical Properties of Fluorinated Epoxy Resin.

Nanomaterials (Basel) 2021 May 20;11(5). Epub 2021 May 20.

State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China.

Traditional epoxy resin (EP) materials have difficulty to meet the performance requirements in the increasingly complex operating environment of the electrical and electronic industry. Therefore, it is necessary to study the design and development of new epoxy composites. At present, fluorinated epoxy resin (F-EP) is widely used, but its thermal and mechanical properties cannot meet the demand. Read More

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Elastic Properties and Energy Dissipation Related to the Disorder-Order Ferroelectric Transition in a Multiferroic Metal-Organic Framework [(CH)NH][Fe(HCOO)] with a Perovskite-Like Structure.

Materials (Basel) 2021 May 5;14(9). Epub 2021 May 5.

School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.

The elastic properties and the coupling of ferroelasticity with ferromagnetism and ferroelectricy are crucial for the development of multiferroic metal-organic frameworks (MOFs) with strong magnetoelectric coupling. Elastic properties and energy dissipation related to the disorder-order ferroelectric transition in [(CH)NH][Fe(HCOO)] were studied by differential scanning calorimetry (DSC), low temperature X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). DSC result indicated the transition near 164 K. Read More

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Transition from horizontal expansion to vertical growth in the oyster prismatic layer.

Biochem Biophys Res Commun 2021 Jul 28;563:47-53. Epub 2021 May 28.

Protein Science Laboratory of the Ministry of Education, School of Life Science, Tsinghua University, Beijing, 100084, China; Department of Biotechnology and Biomedicine, Yangtze Delta Region Institute of Tsinghua University, Jiaxing, Zhejiang Province, 314006, China. Electronic address:

Biomimetic materials inspired by biominerals have substantial applications in various fields. The prismatic layer of bivalve molluscs has extraordinary flexibility compared to inorganic CaCO. Previous studies showed that in the early stage, minerals expanded horizontally and formed prism domains as a Voronoi division, while the evolution of the mature prisms were thermodynamically driven, which was similar to grain growth. Read More

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Generalizable Trends in Electrochemical Protonation Barriers.

J Phys Chem Lett 2021 Jun 26;12(21):5193-5200. Epub 2021 May 26.

Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.

Predicting activation energies for reaction steps is essential for modeling catalytic processes, but accurate barrier simulations often require considerable computational expense, especially for electrochemical reactions. Given the challenges of barrier computations and the growing promise of electrochemical routes for various processes, generalizable energetic trends in electrochemistry can significantly aid in analyzing reaction networks and building microkinetic models. Herein, we employ density functional theory and machine learning nudged elastic band models to simulate electrochemical protonation of *C, *N, and *O monatomic adsorbates from hydronium on a series of transition metal surfaces. Read More

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Microscopic origin of graphene nanosheets derived from coal-tar pitch by treating AlC as the intermediate.

Phys Chem Chem Phys 2021 Jun;23(21):12449-12455

Key Laboratory of Eco-materials Advanced Technology, College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, P. R. China.

The development of environmentally friendly, simple process and low cost synthesis methods for preparing graphene nanosheets (GNs) has attracted global interest. In this work, a simple and efficient method to synthesize GNs deriving from coal-tar pitch has been proposed from both experimental and theoretical point of views. The XRD, TEM and Raman results demonstrate that precursor Al4C3 could provide a growth environment for the final product of GNs. Read More

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Supersoft Elastic Bottlebrush Microspheres with Stimuli-Responsive Color-Changing Properties in Brine.

Langmuir 2021 Jun 26;37(22):6744-6753. Epub 2021 May 26.

Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300350, China.

Solvent-free supersoft elastomer is highly desirable for building photonic structures with significant stimuli-responsive color changes. We report supersoft elastic porous microspheres with vivid structural colors obtained via self-assembly of amphiphilic bottlebrush block copolymers at the water/oil interface templated by ordered water-in-oil-in-water double emulsions. The porous structure is composed of cross-linked bottlebrush polydimethylsiloxane (PDMS) as the supersoft elastic skeleton and bottlebrush poly(ethylene oxide) (PEO) as the internal responsive layer. Read More

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Impact of nanosizing on the formation and characteristics of polymethacrylate films: micro- nano-suspensions.

Pharm Dev Technol 2021 Jun 7:1-11. Epub 2021 Jun 7.

School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK.

Aqueous-based film coating suspensions are associated with reliance on alkalinising reagents and poor film formation. The impact of particle size in this process and resultant film properties remains unclear. This study offers the first direct comparison of film formation properties between aqueous micro- and nano-suspensions of the enteric polymer Eudragit S100. Read More

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Universality of plastic instability and mechanical yield in metallic glasses.

J Phys Condens Matter 2021 Jun 17;33(31). Epub 2021 Jun 17.

Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu 632014, India.

The generic response of a wide range of amorphous solids is the average increase of stress upon external loading until the yielding transition point, after which elasto-plastic steady state sets in. The stress-strain response comprises of a series of elastic branches interspersed with plastic drops. The ubiquitousness of these phenomena indicates universality, independent of material property, but the literature predominantly deals with specific materials. Read More

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Microstructural and mechanical recovery of bone in ovariectomized rats: The effects of menaquinone-7.

J Mech Behav Biomed Mater 2021 Aug 21;120:104571. Epub 2021 May 21.

Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University, Japan.

The loss of bone quantity and quality in postmenopausal female patients can be a problem for dental treatment. A sufficient intake of nutrients such as calcium, magnesium, and vitamins D and K is likely correlated with the mechanical properties of bone. In particular, vitamin K2, also called menaquinone (MK), inhibits bone loss in postmenopausal women. Read More

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Gelator-Enhanced Organohydrogels with Switchable Mechanics and High-Strain Shape-Memory Capacity.

Langmuir 2021 Jun 24;37(22):6711-6721. Epub 2021 May 24.

Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province, Chengdu 610500, P. R. China.

Hydrogels and organogels, as two crucial representatives of soft materials, have attracted immense interest. However, they develop independently along two parallel lines, and these gels with single networks have their inherent drawbacks. For example, hydrogels tend to freeze, and organogels are usually brittle. Read More

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Soft Substrate Culture to Mechanically Control Cardiac Myofibroblast Activation.

Methods Mol Biol 2021 ;2299:171-179

Department of Physiology and Pathophysiology, Institute of Cardiovascular Sciences, University of Manitoba, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.

Two-dimensional cell culture is the primary method employed for proof-of-concept studies in most molecular biology labs. While immortalized cell lines are convenient and easy to maintain for extended periods in vitro, their inability to accurately represent genuine cell physiology-or pathophysiology-presents a challenge for drug discovery, as most results are not viable for the transition to clinical trial. The use of primary cells is a more biologically relevant approach to this issue; however, simulating in vitro what is observed in vivo is exigent at best. Read More

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January 2021

Chromonic liquid crystals and packing configurations of bacteriophage viruses.

Philos Trans A Math Phys Eng Sci 2021 Jul 24;379(2201):20200111. Epub 2021 May 24.

Department of Mathematics, MSB, 2150, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.

We study equilibrium configurations of hexagonal columnar liquid crystals in the context of characterizing packing structures of bacteriophage viruses in a protein capsid. These are viruses that infect bacteria and are currently the focus of intense research efforts, with the goal of finding new therapies for bacteria-resistant antibiotics. The energy that we propose consists of the Oseen-Frank free energy of nematic liquid crystals that penalizes bending of the columnar directions, in addition to the cross-sectional elastic energy accounting for distortions of the transverse hexagonal structure; we also consider the isotropic contribution of the core and the energy of the unknown interface between the outer ordered region of the capsid and the inner disordered core. Read More

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Cell orientation under stretch: Stability of a linear viscoelastic model.

Math Biosci 2021 07 17;337:108630. Epub 2021 May 17.

Department of Mathematical Sciences "G.L. Lagrange" Dipartimento di Eccellenza 2018-2022, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy. Electronic address:

The sensitivity of cells to alterations in the microenvironment and in particular to external mechanical stimuli is significant in many biological and physiological circumstances. In this regard, experimental assays demonstrated that, when a monolayer of cells cultured on an elastic substrate is subject to an external cyclic stretch with a sufficiently high frequency, a reorganization of actin stress fibres and focal adhesions happens in order to reach a stable equilibrium orientation, characterized by a precise angle between the cell major axis and the largest strain direction. To examine the frequency effect on the orientation dynamics, we propose a linear viscoelastic model that describes the coupled evolution of the cellular stress and the orientation angle. Read More

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Tilted elastic lines with columnar and point disorder, non-Hermitian quantum mechanics, and spiked random matrices: Pinning and localization.

Phys Rev E 2021 Apr;103(4-1):042120

School of Mathematics and Statistics, University College Dublin, Dublin 4, Ireland.

We revisit the problem of an elastic line (such as a vortex line in a superconductor) subject to both columnar disorder and point disorder in dimension d=1+1. Upon applying a transverse field, a delocalization transition is expected, beyond which the line is tilted macroscopically. We investigate this transition in the fixed tilt angle ensemble and within a "one-way" model where backward jumps are neglected. Read More

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Elastic moduli of body-centered cubic lattice near rigidity percolation threshold: Finite-size effects and evidence for first-order phase transition.

Phys Rev E 2021 Apr;103(4-1):042314

Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-1211, USA.

Extensive numerical simulations of rigidity percolation with only central forces in large three-dimensional lattices have indicated that many of their topological properties undergo a first-order phase transition at the rigidity percolation threshold p_{ce}. In contrast with such properties, past numerical calculations of the elastic moduli of the same lattices had provided evidence for a second-order phase transition. In this paper we present the results of extensive simulation of rigidity percolation in large body-centered cubic (bcc) lattices, and show that as the linear size L of the lattice increases, the elastic moduli close to p_{ce} decrease in a stepwise, discontinuous manner, a feature that is absent in lattices with L<30. Read More

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Universality of Time-Temperature Scaling Observed by Neutron Spectroscopy on Bottlebrush Polymers.

Nano Lett 2021 May 14;21(10):4494-4499. Epub 2021 May 14.

Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States.

The understanding of materials requires access to the dynamics over many orders of magnitude in time; however, single analytical techniques are restricted in their respective time ranges. Assuming a functional relationship between time and temperature is one viable tool to overcome these limits. Despite its frequent usage, a breakdown of this assertion at the glass-transition temperature is common. Read More

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Quadrupolar charge dynamics in the nonmagnetic FeSe S superconductors.

Proc Natl Acad Sci U S A 2021 May;118(20)

Department of Physics & Astronomy, Rutgers University, Piscataway, NJ 08854;

We use polarization-resolved electronic Raman spectroscopy to study quadrupolar charge dynamics in a nonmagnetic [Formula: see text] superconductor. We observe two types of long-wavelength [Formula: see text] symmetry excitations: 1) a low-energy quasi-elastic scattering peak (QEP) and 2) a broad electronic continuum with a maximum at 55 meV. Below the tetragonal-to-orthorhombic structural transition at [Formula: see text], a pseudogap suppression with temperature dependence reminiscent of the nematic order parameter develops in the [Formula: see text] symmetry spectra of the electronic excitation continuum. Read More

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Dopant Segregation Inside and Outside Dislocation Cores in Perovskite BaSnO and Reconstruction of the Local Atomic and Electronic Structures.

Nano Lett 2021 May 11;21(10):4357-4364. Epub 2021 May 11.

Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, United States.

Distinct dopant behaviors inside and outside dislocation cores are identified by atomic-resolution electron microscopy in perovskite BaSnO with considerable consequences on local atomic and electronic structures. Driven by elastic strain, when A-site designated La dopants segregate near a dislocation core, the dopant atoms accumulate at the Ba sites in compressively strained regions. This triggers formation of Ba vacancies adjacent to the core atomic sites resulting in reconstruction of the core. Read More

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Slip of soft permeable particles near a wall.

Soft Matter 2021 May;17(17):4538-4549

McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.

The slip and stick of soft permeable particles sliding near a smooth surface is determined by computing flow, pressure and shape of a particle pressed against a surface due to the osmotic pressure of the surrounding suspension and its translation at constant velocity parallel to the surface. We present a poro-elastohydrodynamic lubrication theory that accounts for the interplay of the viscous pressure force on the elastic deformation of the particle and the flow through the particle pores. At high particle velocities, the particles move along an elastohydrodynamic film of fluid causing the particles to slip on the surface. Read More

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Sugar-Pucker Force-Induced Transition in Single-Stranded DNA.

Int J Mol Sci 2021 Apr 29;22(9). Epub 2021 Apr 29.

Small Biosystems Lab, Condensed Matter Physics Department, Universitat de Barcelona, Carrer de Martí i Franquès 1, 08028 Barcelona, Spain.

The accurate knowledge of the elastic properties of single-stranded DNA (ssDNA) is key to characterize the thermodynamics of molecular reactions that are studied by force spectroscopy methods where DNA is mechanically unfolded. Examples range from DNA hybridization, DNA ligand binding, DNA unwinding by helicases, etc. To date, ssDNA elasticity has been studied with different methods in molecules of varying sequence and contour length. Read More

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