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Showing 1 to 20 of 27 for “"Dynamic Compression"”.
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Multidimensional dynamic compression system modeling
… equations of a one-dimensional stage-by-stage dynamic compression system model was developed and validated. The improved method was then applied to two-dimensional post-stall models. The improvement in robustness was achieved by modeling the governing equations with upwind differencing and use …
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Prediction of Articular Cartilage Remodeling During Dynamic Compression with a Finite Element Model
… performed to test the hypothesis that applying dynamic unconfined compression during culture produces het- erogeneous remodeling in newborn bovine articular cartilage explants. Het- erogeneous measures of cartilage microstructure were obtained by biochemical assays and quantified polarized light …
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Poroelastic Finite Element Analysis of a Heterogeneous Articular Cartilage Explant Under Dynamic Compression in ABAQUS
… (± 2% strain), low</p> <p>frequency (0.1 Hz) dynamic unconfined compression (UCC). A strong correlation</p> <p>has been made between the relative fluid velocity and stimulation of</p> <p>glycosaminoglycan synthesis. A contour plot of the model shows the relative fluid</p> <p>velocity during …
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In vitro culture of a chondrocyte-seeded peptide hydrogel and the effects of dynamic compression
… culture conditions and also when subjected to dynamic compression. During 4 weeks of culture in vitro, chondrocytes seeded within the peptide hydrogel retained their morphology and developed a cartilage-like ECM rich in proteoglycans and type II collagen, indicative of a stable chondrocyte …
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In vitro model of injury/cytokine-induced cartilage catabolism modulated by dynamic compression, growth factors, and glucocorticoids
… cytokines (TNF-Q and IL-6). Intermittent dynamic compression was then applied to simulate different strain levels known to exist in vivo after joint injury. Strain-dependent modulation of aggrecan biosynthesis and degradation, aggrecanase cleavage of aggrecan, chondrocyte gene expression …
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Effects of O-Ring Elastomers with Conventional and Synthesized Aviation Fuels with a Novel Elastomer Dynamic Compression System
… methods for viewing the data in percentage of compression. Novel technical advancements of this research are: (i) design and manufacture an apparatus that records O-ring behavior with flowing fuel in one second intervals over long periods of time utilizing four highly accurate load sensors, …
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A Biomechanical Comparison of 3.5 Locking Compression Plate Fixation to 3.5 Limited Contact Dynamic Compression Plate Fixation in a Canine Cadaveric Distal Humeral Metaphyseal Gap Model
… the biomechanical properties of 3.5 locking compression plate (LCP) fixation to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model in static axial compression and cyclic axial compression and torsion. Study Design- …
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Investigation of Cellular Responses Activated by Mechanical Compression in Equine Chondrocytes: Device Design, Construction and Testing
… was to investigate the effects of mechanical compression on gene regulation, proteoglycan (PG) synthesis and activation of signaling pathways. To achieve this goal a simple oscillatory displacement controlled device was designed to provide uniaxial unconfined strain to cell constructs. Static …
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Behavior of passaged chondrocytes in collagen-glycosaminoglycan scaffolds : effects of cross-linking, mechanical loading, and genetic modification of the scaffold
… throughout a 4-week culture. Static mechanical compression (0-50% strain) applied to cell-seeded EDAC cross-linked scaffolds decreased rates of protein and GAG synthesis while dynamic compression (3% sine amplitude, 0.1 Hz) increased rates of biosynthesis over a 24-hour period. These results …
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Progression of chondrocyte signaling responses to mechanical stimulation in 3-D gel culture
… to disrupt integrin-matrix interactions during dynamic compression of chondrocytes in 3-D agarose culture. At early days in culture, blocking [alpha]v[beta]3 integrin abolished dynamic compression stimulation of proteoglycan synthesis, independent of effects in free-swell culture, while blocking …
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Probabilistic analysis of compression system stability using importance sampling
… new approach based on Importance Sampling and a dynamic compression system model. In contrast to ordinary Monte Carlo methods Importance Sampling offers reduced confidence intervals, reduced number of samples and reduced model execution times. The new approach avoids some of the problematic …
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Enhancing Mesenchymal Stem Cell Chondrogenesis for Cartilage Tissue Engineering
… formed at a higher seeding density. Long-term dynamic compression initiated 3 days after MSC encapsulation impaired functional properties; in contrast, dynamic compression initiated after 3 weeks of chondrogenic pre-culture improved mechanical function. While these strategies enhanced …
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Extended mechanical stimulations of cartilage for growth and repair
… day mechanical loading protocol consisting of dynamic sinusoidal compression results in long term extracelluar matrix macromolecule biosynthesis and increased biosynthetic rates in the cartilage system. The protocol uses total glycosaminoglycan and DNA content assays to measure matrix …
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Loudness models for rehabilitative audiology
… hearing-impaired listener with different dynamic compression algorithms (chapter 2). In chapter 3 two methods (loudness matching and categorical loudness scaling) for assessing loudness perception are tested against each other. The reminder of the thesis is devoted towards modeling normal …
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High velocity impact fracture
An in-depth understanding of dynamic ductile fracture is one of the most important steps to improve the survivability of critical structures such as the lost Twin Towers. In the present thesis, the macroscopic fracture modes and the fracture mechanisms of ductile structural components under high …
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Chondrocyte gene expression and intracellular signaling pathways in cartilage mechanotransduction
… induced by in vivo loading. Constant (static) compression of cartilage explants induces a transient hydrostatic pressure buildup and fluid exudation from the compacted matrix until relaxation leads to a new equilibrium compressed state. Dynamic compression induces cyclic matrix deformation, …
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A wide-range axial-flow compressor stage performance model
Dynamic compression system response is a major concern in the operability of aircraft gas turbine engines. Computer models have been developed to predict compressor response to changing operating conditions. These models require a knowledge of the steady state operating characteristics as inputs, …
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Dynamic response of glass under low-velocity impact and high strain-rate compression loading
<p>In this research, the dynamic response and energy absorption characteristics of four different types of commercially available glass have been investigated experimentally. Soda Lime, Starphire, Borosilicate, and Fused Silica were characterized using a Dynatup 8250 drop weight impact test system, …
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Effects of biochemical and mechanical stimulation of articular chondrocytes in collagen-GAG scaffolds : extracellular matrix biosynthesis and scaffold stiffness
… chondrocyte-seeded scaffolds were subjected to dynamic compression and the effects of this treatment on the proliferation of the chondrocytes, their synthesis of ECM, and the stiffness of the scaffolds were measured. The results of these experiments were inconclusive. Analysis indicated that …
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