483 research outputs found

    Home Program of Hip Abductor Exercises: Effect on Knee Joint Loading, Strength, Function and Pain in Persons with Knee Osteoarthritis

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    Background Hip abductor muscle weakness may result in impaired frontal-plane pelvic control during gait, leading to greater medial compartment loading in people with knee osteoarthritis (OA). Objective This study investigated the effect of an 8-week home strengthening program for the hip abductor muscles on knee joint loading (measured by the external knee adduction moment during gait), strength (force-generating capacity), and function and pain in individuals with medial knee OA. Design The study design was a nonequivalent, pretest-posttest, control group design. Setting Testing was conducted in a motor performance laboratory. Patients An a priori sample size calculation was performed. Forty participants with knee OA were matched for age and sex with a control group of participants without knee OA. Intervention Participants with knee OA completed a home hip abductor strengthening program. Measurements Three-dimensional gait analysis was performed to obtain peak knee adduction moments in the first 50% of the stance phase. Isokinetic concentric strength of the hip abductor muscles was measured using an isokinetic dynamometer. The Five-Times-Sit-to-Stand Test was used to evaluate functional performance. Knee pain was assessed with the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire. Results Following the intervention, the OA group demonstrated significant improvement in hip abductor strength, but not in the knee adduction moment. Functional performance on the sit-to-stand test improved in the OA group compared with the control group. The OA group reported decreased knee pain after the intervention. Limitations Gait strategies that may have affected the knee adduction moment, including lateral trunk lean, were not evaluated in this study. Conclusions Hip abductor strengthening did not reduce knee joint loading but did improve function and reduce pain in a group with medial knee OA

    IMECE2005-79902 CONVECTIVE HEAT TRANSFER OF LAMINAR, SINGLE-PHASE FLOW IN RANDOMLY ROUGH MICROTUBES

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    Abstract Convective heat transfer of laminar, single-phase flow in rough microtubes is studied. Wall roughness and slope are assumed to possess Gaussian, isotropic distributions. Fractal concepts are used to model the rough microtube. It is shown that due to the existence of wall roughness, both cross-sectional and inside surface areas are increased. A new concept is defined as a figure of merit for assessing thermal performance of rough microtubes. As a result of increasing roughness, an enhancement is observed in the thermal performance of microtubes. The present model can be extended to analyze other geometries such as rectangular and trapezoidal microchannels. 1 Post-Doctoral Fellow. Mem. ASME. Corresponding author. Email: [email protected]. 2 Distinguished Professor Emeritus. Fellow ASME. 3 Associate Professor and Director of MHTL. Mem. ASME

    Thermal contact resistance at low contact pressure: effect of elastic deformation

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    Abstract Existing models over-predict the thermal contact resistance of conforming rough joints at low contact pressures. However, the applicable pressure range in some applications such as microelectronics cooling is low. A new model is developed which is more suitable for low pressures. The effect of elastic deformations beneath the plastically deformed microcontacts is determined by superimposing normal deformations due to self and neighboring contact spots in an elastic half-space. A parametric study reveals that the elastic deformation effect is an important phenomenon at low contact pressures. The model is compared with data and good agreement is observed at low contact pressures

    Synthesis and Luminescence Modulation of Pyrazine-Based Gold(III) Pincer Complexes

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    The first examples of pyrazine-based gold(III) pincer complexes have been synthesized; their intense photoemissions can be modified by interactions with the non-coordinating pyrazine-N atom. Luminescence modulation is possible without the need for altering the ligand framework. Emissions shift from red (77 K) to blue (298 K) due to thermally activated delayed fluorescence (TADF

    Fluid Flow Around and Heat Transfer from Elliptical Cylinders: Analytical Approach

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    An integral method of boundary-layer analysis is employed to derive closed-form expressions for the calculation of total drag and average heat transfer for flow across an elliptical cylinder under isothermal and isoflux thermal boundary conditions. The Von Kármán-Pohlhausen integral method is used to solve the momentum and energy equations for both thermal boundary conditions. A fourth-order velocity profile in the hydrodynamic boundary layer and a third-order temperature profile in the thermal boundary layer are used. The present results are in good agreement with existing experimental/numerical data and, in the limiting cases, can be used for circular cylinders and finite plates. = complete elliptic integral of second kind e = eccentricity

    Stacked Packaging Laminar-Convection-Cooled Printed Circuit Using the Entropy Generation Minimization Method

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76567/1/AIAA-30451-562.pd
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