Read by QxMD icon Read


Maud Creze, Antoine Nordez, Marc Soubeyrand, Laurence Rocher, Xavier Maître, Marie-France Bellin
Imaging plays an important role in the diagnosis and therapeutic response evaluation of muscular diseases. However, one important limitation is its incapacity to assess the in vivo biomechanical properties of the muscles. The emerging shear wave sonoelastography technique offers a quantifiable spatial representation of the viscoelastic characteristics of skeletal muscle. Elastography is a non-invasive tool used to analyze the physiologic and biomechanical properties of muscles in healthy and pathologic conditions...
December 9, 2017: Skeletal Radiology
Diana T Pham, Joe G Shapter, John J Costi
Disc degeneration is a common medical affliction whose origins are not fully understood. An improved understanding of its underlying mechanisms could lead to the development of more effective treatments. The aim of this paper was to investigate the effect of (1) degeneration, (2) circumferential region and (3) strain rate on the microscale mechanical properties (toe region modulus, linear modulus, extensibility, phase angle) of individual fibre bundles in the anulus fibrosus lamellae of the human intervertebral disc...
November 28, 2017: Journal of Biomechanics
Christian Ganser, Caterina Czibula, Daniel Tscharnuter, Thomas Schöberl, Christian Teichert, Ulrich Hirn
Viscoelastic properties are often measured using probe based techniques such as nanoindentation (NI) and atomic force microscopy (AFM). Rarely, however, are these methods verified. In this article, we present a method that combines contact mechanics with a viscoelastic model (VEM) composed of springs and dashpots. We further show how to use this model to determine viscoelastic properties from creep curves recorded by a probe based technique. We focus on using the standard linear solid model and the generalized Maxwell model of order 2...
December 8, 2017: Soft Matter
Roy D Altman, Vinod Dasa, Jun Takeuchi
Objective Summarize the biologic effects of Supartz FX for knee osteoarthritis (OA), the first worldwide clinically approved intra-articular (IA) hyaluronic acid (HA) product. Design To determine the mechanism of action from preclinical and clinical studies, a literature search was conducted of Supartz FX using academic databases from 1987 to 2016. Articles on Supartz FX that deal with its mechanisms of action were extracted, categorized, and reviewed. Results Supartz FX has 2 potential mechanisms of action: (1) biomechanical: IA Supartz FX directly improves the viscoelasticity and lubrication of synovial fluid; (2) physiologic: IA Supartz FX penetrates synovium and cartilage tissues to reach HA receptors on the surface of synoviocytes and chondrocytes...
January 2018: Cartilage
Yi-An Lin, Myungshim Kang, Wei-Chiang Chen, Yu-Chuan Ou, Andrew G Cheetham, Pei-Hsun Wu, Denis Wirtz, Sharon M Loverde, Honggang Cui
Supramolecular filament hydrogels are an emerging class of biomaterials that hold great promise for regenerative medicine, tissue engineering, and drug delivery. However, fine-tuning of their bulk mechanical properties at the molecular level without altering their network structures remains a significant challenge. Here we report an isomeric strategy to construct amphiphilic peptides through the conjugation of isomeric hydrocarbons to influence the local viscoelastic properties of their resulting supramolecular hydrogels...
December 7, 2017: Biomaterials Science
T Richard Nichols
This review is an update on the role of force feedback from Golgi tendon organs in the regulation of limb mechanics during voluntary movement. Some current ideas about the role of force feedback are based on circuit motifs linking idealized systems of agonists, synergists and antagonistic muscles. Force feedback is widely distributed across the muscles of a limb and cannot be understood based on these circuit motifs. Muscle architecture similarly cannot be understood in terms of idealized systems. It is hypothesized that distributed force feedback better represents the complex mechanical interactions of muscles, including viscoelastic coupling and inertial coupling across joints and axes of rotation...
December 6, 2017: Journal of Neurophysiology
Atiđa Selmani, Antonio Tavera-Vazquez, Cristina Garza, Rolando C Castillo
We present the detailed rheological changes that occur when small quantities of single-wall carbon nanotubes are dispersed in a polyacrylic acid water solution, around the overlap polymer concentration, up to the gel point. Here, pH is used to tune the gel formation. Suspensions of nanotubes at pH ≤ 5 are exfoliated and dispersed by the polymer. Contacts between the nanotubes are mainly through polymer entangling, and the suspension is viscoelastic. At pH > 5, the polymer is charged, and the solution is not so good solvent for the nanotubes anymore...
December 6, 2017: Journal of Physical Chemistry. B
Sungmin Jung, Twinkal Patel, Jung Kwon Oh
A new approach based on macromolecular engineering through thermoreversibility is reported to fabricate the engineered gel networks of thermally labile branched polymers exhibiting robust self-healing. This approach centers on the synthesis of linear polymers having Diels-Alder cycloadducts in the backbones (DALPs) through A2 + B2 step-growth polymerization of a difunctional furan and a difunctional maleimide. Reactive mixtures of the resulting DALP with a polyfuran at elevated temperature allow for the formation of engineered gel networks through random dissociation of backbone DA linkages of the DALPs by retro-Diels-Alder reaction, followed by their reconstruction in the presence of polyfuran (with functionality > 2) by Diels-Alder reaction...
December 6, 2017: Macromolecular Rapid Communications
Soumyajyoti Chatterjee, Kadhiravan Shanmuganathan, Guruswamy Kumaraswamy
Polymeric foams used in furniture and seating applications for automotives and aircraft rely on incorporation of environmentally hazardous fire retardant additives to meet fire safety norms. This has occasioned significant interest in novel approaches to the elimination of fire retardant additives. Foams based on polymer nanocomposites or based on fire retardant coatings show compromised mechanical performance and require additional processing steps. Here, we demonstrate a one-step preparation of a fire retardant ice-templated inorganic/polymer hybrid that does not incorporate fire retardant additives...
December 5, 2017: ACS Applied Materials & Interfaces
Stefani Cortés-Camargo, Raquel Gallardo-Rivera, Blanca E Barragán-Huerta, Octavio Dublán-García, Angélica Román-Guerrero, César Pérez-Alonso
In this work the physicochemical and functional properties of mesquite gum (MG) and nopal mucilage (NM) mixtures (75-25, 50-50, 25-75) were evaluated and compared with those of the individual biopolymers. MG-NM mixtures exhibited more negative zeta potential (ZP) values than those displayed by MG and NM, with 75-25 MG-NM showing the most negative value (-14.92 mV at pH = 7.0), indicative that this biopolymer mixture had the highest electrostatic stability in aqueous dispersions. Viscosity curves and strain amplitude sweep of aqueous dispersions (30% w/w) of the individual gums and their mixtures revealed that all exhibited shear thinning behavior, with NM having higher viscosity than MG, and all displaying fluid-like viscoelastic behavior where the loss modulus predominated over the storage modulus (G″>G')...
December 5, 2017: Journal of Food Science
Alexey Smoluk, Leonid Smoluk, Ruslan Lisin, Yuri Protsenko
Our work involved experimental study of the influence of actomyosin complexes and the main structural components of the myocardial tissue - connective tissue collagen framework and cardiomyocytes - on the characteristics of viscoelastic hysteresis at different frequencies. In this paper a new method was introduced for the analysis of the viscoelastic characteristics of the force hysteresis in the isolated myocardial preparation for the assessment of mechanical energy expenditure in the tension-compression cycle...
2017: Acta of Bioengineering and Biomechanics
Abas Ramiar, Morsal Momenti Larimi, Ali Akbar Ranjbar
PURPOSE: Hemodynamic factors, such as Wall Shear Stress (WSS), play a substantial role in arterial diseases. In the larger arteries, such as the carotid artery, interaction between the vessel wall and blood flow affects the distribution of hemodynamic factors. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a second-grade viscoelastic fluid and the effects of viscoelastic on blood flow in carotid artery is investigated. METHODS: Pulsatile flow studies were carried out in a 3D model of carotid artery...
2017: Acta of Bioengineering and Biomechanics
Kiminori Sato
1. There is growing evidence to suggest that the cells in the maculae flavae are tissue stem cells of the human vocal fold and maculae flavae are a candidate for a stem cell niche. 2. The latest research shows that the cells in the human maculae flavae are involved in the metabolism of extracellular matrices that are essential for the viscoelasticity in the human vocal fold mucosa as a vibrating tissue, and considered to be important cells in the growth, development, and aging of the human vocal fold mucosa...
2017: Advances in Experimental Medicine and Biology
Amanda Andersen, Marie Krogsgaard, Henrik Birkedal
Mussel-inspired hydrogels held together by reversible catecholato-metal coordination bonds have recently drawn great attention owing to their attractive self-healing, viscoelastic and adhesive properties together with their pH-responsive nature. A major challenge in these systems is to orchestrate the degree of catechol oxidation that occurs under alkaline conditions in air and has a great impact on the aforementioned properties because it introduces irreversible covalent cross-links to the system, which stiffens the hydrogels but consume catechols needed for self-healing...
December 4, 2017: Biomacromolecules
T Kairaliyeva, E V Aksenenko, N Mucic, A V Makievski, V B Fainerman, Reinhard Miller
Surface tension and dilational viscoelasticity of solutions of various surfactants measured with bubble and drop profile analysis tensiometry are discussed. The study also includes experiments on the co-adsorption of surfactant molecules from a solution drop and alkane molecules from saturated alkane vapor phase. Using experimental data for 12 surfactants with different surface activities, it is shown that depletion due to adsorption of surfactant from the drop bulk can be significant. An algorithm is proposed quantitatively to take into consideration the depletion effect which is required for a correct description of the co-adsorption of alkanes on the solution drop surface and the correct analysis of experimental dynamic surface tension data to determine the adsorption mechanism...
2017: Journal of Surfactants and Detergents
Josef Hartl, Astrid Peschel, Diethelm Johannsmann, Patrick Garidel
Making use of a quartz crystal microbalance (QCM), concentrated solutions of therapeutic antibodies were studied with respect to their behavior under shear excitation with frequencies in the MHz range. At high protein concentration and neutral pH, viscoelastic behavior was found in the sense that the storage modulus, G', was nonzero. Fits of the frequency dependence of G'(ω) and G''(ω) (G'' being the loss modulus) using the Maxwell-model produced good agreement with the experimental data. The fit parameters were the relaxation time, τ, and the shear modulus at the inverse relaxation time, G* (at the "cross-over frequency" ωC = 1/τ)...
December 4, 2017: Physical Chemistry Chemical Physics: PCCP
Jaana Koskela, David A V Morton, Peter J Stewart, Anne M Juppo, Satu Lakio
Mechanofusion is a dry coating method that can be used to improve the flowability of cohesive powder by coating host particles with a lubricant, for example magnesium stearate (MgSt). It has been shown previously that fragmenting material can under some circumstances be mechanofused with MgSt without impairing compactibility of the powder and without reducing the dissolution rate of the resulting tablets. However, the effects on material with viscoelastic behaviour, known to be sensitive for the negative effects of MgSt, is not known...
November 30, 2017: International Journal of Pharmaceutics
Katarzyna Boniewicz-Szmyt, Stanisław Józef Pogorzelski
Spatial and temporal variability of natural surfactant sea surface film structural parameters were evaluated from force-area isotherms, film pressure-temperature isochors, dynamic surface tension-time relations performed on samples collected in Baltic Sea shallow coastal waters. The film structure state was postulated as a 10-D dimensionless vector created from the normalized thermodynamic, adsorptive, and viscoelastic film parameters. The normalization procedure is based on the concept of self-corresponding states known in thermodynamics...
December 3, 2017: Environmental Science and Pollution Research International
M H Korayem, S Shahali, Z Rastegar
Plasma membrane of most cells is not smooth. The surfaces of both small and large micropermeable cells are folded and corrugated which makes mammalian cells to have a larger membrane surface than the supposed ideal mode, that is, the smooth sphere of the same volume. Since cancer is an anthropic disease, cancer cells tend to have a larger membrane area than normal cells. Therefore, cancer cells have higher folding factor and larger radius than normal and healthy cells. On the other hand, the prevalence of breast cancer has prompted researchers to improve the treatment options raised for the disease in the past...
December 2, 2017: Biomechanics and Modeling in Mechanobiology
Alberto A Martinez, Avery B Chakravarty, Cheryl E Quenneville
Axial impacts to the lower leg during debilitating events such as frontal automotive collisions and military underbody blasts can cause significant injuries to the tibia. Several studies have conducted axial impact tests to determine the injury limits of the lower leg, mostly focused on automotive intrusions, resulting in an established force criterion for injury assessments. Due to the viscoelastic properties of bone, it remains unclear whether results from automotive experiments can be applied to higher-rate military blasts...
November 10, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"