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Results 201 - 250 of 778
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Zhao Zhihe - - 2008
BACKGROUND: The studies on biomechanics of orthodontic tooth movement (OTM) are mainly performed at analytical, tissue and cellular levels. The prime aim of this study was to elucidate the periodontal response to orthodontic force loading by integrating biomechanical and biological approaches. METHODS: We designed and conducted a multilevel study consisting ...
Hermsdörfer J J Clinical Neuropsychology Research Group (EKN), Academic Hospital Munich-Bogenhausen, Technical University of Munich, Munich, Germany. - - 2008
The grip force used to grasp and hold an object is modulated synchronously and precisely with a self-produced load indicating predictive feedforward control. It is unclear whether an externally produced load can be anticipated with similar feedforward-timing and precision if it can be predicted, e.g., because it has a periodic ...
Schwab Joseph H - - 2008
The extended femoral trochanteric osteotomy allows excellent exposure of the proximal femoral canal, which facilitates resection of the canal's contents during revision total hip arthroplasty. Once the proximal femoral canal has been evacuated and a new femoral component has been placed, the osteotomy should be fixed in proper position to ...
Slifkin Andrew B AB Department of Psychology, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA. - - 2008
Actual and imagined action may be governed by common information and neural processes. This hypothesis has found strong support from a range of chronometric studies showing that it takes the same amount of time to actually move and to imagine moving. However, exceptions have been observed when actual and imagined ...
Cronin John B - - 2007
Optimizing transference of gym-based strength and power gains to sporting performance necessitates a physiological and biomechanical understanding of the weight-training exercise as well as the sporting activity. With this in mind, this paper describes the kinematics and kinetics associated with a seated row. The maximal strength and concentric power-load spectrum ...
Markovic Goran - - 2007
PURPOSE: The aim of this study was to evaluate the effect of external loading on mechanics of vertical jumping. We hypothesized that the muscular mechanical output could be higher under no-load conditions than in the presence of either positive or negative external loads. METHODS: Fifteen physically active men performed maximal ...
Jin Xin - - 2007
The pia-arachnoid complex (PAC) covering the brain plays an important role in the mechanical response of the brain due to impact or inertial loading. The mechanical properties of the bovine PAC under tensile loading have been characterized previously. However, the transverse properties of this structure, such as shear and normal ...
Ai Bao-quan - - 2007
Based on recent work [L. Machura, M. Kostur, P. Talkner, J. Luczka, and P. Hanggi, Phys. Rev. Lett. 98, 040601 (2007)], we extend the study of inertial Brownian motors to the case of an asymmetric potential. It is found that some transport phenomena appear in the presence of an asymmetric ...
Nakama Leena H - - 2007
We reported previously the formation of microtears in an in vivo loaded Flexor Digitorum Profundus (FDP) rabbit tendon with a repetition rate of 60 repetitions per minute and a peak force of 15% of maximum peak tetanic force for 80 cumulative hours. Tear area as a percent of tendon area, ...
Li Guoan - - 2008
The knowledge of real-time in-vivo cartilage deformation is important for understanding of cartilage function and biomechanical factors that may relate to cartilage degeneration. This study investigated cartilage contact area and peak contact compressive strain of four healthy human ankle joints as a function of time using a combined magnetic resonance ...
Grover Joel P - - 2007
Blount disease is a deformity of the knee as a result of abnormal mechanical forces known to influence the growth of the physis. Despite existing studies on mechanical forces on chondrocyte cultures or limited growth plate specimens, very little information characterizes the whole growth plate to asymmetrical loading. In this ...
Suhr J - - 2007
Structural components subject to cyclic stress can succumb to fatigue, causing them to fail at stress levels much lower than if they were under static mechanical loading. However, despite extensive research into the mechanical properties of carbon nanotube structures for more than a decade, data on the fatigue behaviour of ...
Sauerland K - - 2007
OBJECTIVE: Alterations in the sulfation pattern of chondroitin sulfate (CS) chains of proteoglycans have been associated with aging and degeneration of articular cartilage. The purpose of the present study was to investigate systematically the effect of load amplitudes, frequencies and load durations of intermittently applied mechanical pressure on the sulfation ...
Abdel-jawad Madhat M - - 2007
The measurement of forces in hypervelocity expansion tubes is not possible using conventional techniques. The stress wave force balance technique can be applied in expansion tubes to measure forces despite the short test times involved. This article presents a new calibration technique for multiple-component stress wave force balances where an ...
Keller Bridget R - - 2007
Decreases in load are important cues in the control of posture and walking. We recorded activities of the tibial campaniform sensilla, receptors that monitor forces as strains in the exoskeleton, in the middle legs of freely moving cockroaches. Small magnets were attached to the thorax and body load was changed ...
Kansiz Mustafa - - 2007
FTIR spectroscopy has been used to monitor and determine the degree of crystallisation in a sample of polyhydroxybutyrate-co-14%valerate (PHB-co-14%HV). Time series spectra of solution-cast films of the polymer revealed spectral changes attributed to the onset of crystallisation. Curve fitting was used to obtain an absolute measure of crystallinity. Mean centred ...
Pérez-García Beatriz - - 2007
In this paper, the electrical transport and mechanical properties of Pt/ZnO Schottky nanocontacts have been studied simultaneously during the formation and rupture of the nanocontacts. By combining multidimensional conducting scanning force spectroscopy with appropriated data processing, the physical relevant parameters (the ideality factor, the Schottky barrier height, and the rupture ...
Mortimer Bruce J P - - 2007
The body's sense of touch is potentially a versatile channel for the conveyance of directional, spatial, command, and timing information. Most practical implementations of vibrotactile systems require compact, light-weight actuators that can be mounted against the body. Eccentric mass motors are widely used for this application, yet their output is ...
Hungerford Barbara A - - 2007
BACKGROUND AND PURPOSE: Clinical indicators of pelvic girdle dysfunction are limited. However, research has shown that the pattern of intrapelvic motion is altered during single-leg support in subjects with pelvic girdle pain (PGP). Functionally, no relative motion should occur within the pelvis during load transfer, whereas anterior rotation of the ...
Pearson Stephen J - - 2007
BACKGROUND: Owing to the viscoelastic nature of tendons it may be that the total excursion and hence strain experienced by the tendon under load may be affected by the duration of contraction. Here we examine the effect of contraction duration on the measured in vivo mechanical properties of the patellar ...
Asundi Krishna R - - 2007
Overuse is thought to be the primary cause of chronic tendon injuries, in which forceful or repetitive loading results in an accumulation of micro-tears leading to a maladaptive repair response. In vitro organ culture models provide a useful method for examining how specific loading patterns affect the cellular response to ...
Arai Kenichiro - - 2007
BACKGROUND: There is limited information regarding the mechanical factors contributing to the progression of posterior tibial tendon dysfunction. Therefore, an investigation of the mechanical forces on the posterior tibial tendon may improve our understanding of this pathology. METHODS: The gliding resistance and excursion of the posterior tibial tendon in the ...
Grigg P - - 2007
We describe a method for evaluating the threshold for cutaneous mechanical sensation in rodents, based on a stimulator that drives a probe against the plantar surface of the foot. The stimulator applies loads that can be either constant or linearly increased. We describe withdrawal responses, including forms of movement that ...
Weinhold Paul S - - 2007
BACKGROUND: Studies have shown that women are at higher risk of sustaining noncontact anterior cruciate ligament (ACL) injuries in specific sports. Recent gait studies of athletic tasks have documented that gender differences in knee movement, muscle activation, and external loading patterns exist. The objective of this study was to determine ...
Ravosa Matthew J - - 2007
Excessive, repetitive and altered loading have been implicated in the initiation of a series of soft- and hard-tissue responses or ;functional adaptations' of masticatory and locomotor elements. Such adaptive plasticity in tissue types appears designed to maintain a sufficient safety factor, and thus the integrity of given element or system, ...
Asundi Krishna - - 2007
Injuries to the tendon (e.g., wrist tendonitis, epicondyltis) due to overuse are common in sports activities and the workplace. Most are associated with repetitive, high force hand activities. The mechanisms of cellular and structural damage due to cyclical loading are not well known. The purpose of this video is to ...
Strassburg Julia - - 2007
The objective of this work is to gain more insight into the processes of oral perception of food texture. Particularly, the limits for detectable thickness differences of objects, which are evaluated in the human mouth, are investigated. In a sensory study small, flexible circular disks (diameter in mm range) of ...
Kedgley Angela E - - 2007
This in vitro study evaluated the effects of four different muscle-loading ratios on active glenohumeral joint abduction. Eight cadaveric shoulders were tested using a shoulder simulator designed to reproduce unconstrained abduction of the humerus via computer-controlled pneumatic actuation. Forces were applied to cables that were sutured to tendons or fixed ...
Kucharová M - - 2007
Mechanical behavior of biological structures under dynamic loading generally depends on elastic as well as viscous properties of biological materials. The significance of "viscous" parameters in real situations remains to be elucidated. Behavior of rheological models consisting of a combination of inertial body and two Voigt's bodies were described mathematically ...
Christensen-Dalsgaard Karen K - - 2007
It is well known that trees adapt their supportive tissues to changes in loading conditions, yet little is known about how the vascular anatomy is modified in this process. We investigated this by comparing more and less mechanically loaded sections in six species of tropical trees with two different rooting ...
Cresson Romain - - 2007
The influence of hydrodynamic conditions on the start-up phase of an inverse turbulent bed bioreactor was investigated. Two identical reactors, differing only by the gas velocity ensuring the carrier fluidization and generating the main hydrodynamic strengths (attrition), were monitored. Regarding the first 96 days, the experiments showed better performances for ...
Rome Lawrence C - - 2006
Vertical movement of the hip during locomotion causes a loaded backpack to be accelerated with each step, which imposes large peak forces on the wearer. Here we show that using bungee cords to suspend the load from a backpack frame reduces not only its vertical movement, and hence its vertical ...
Musselman Kristin E - - 2007
Sensory input is critical for adapting motor outputs to meet environmental conditions. A ubiquitous force on all terrestrial animals is gravity. It is possible that when performing rhythmic movements, animals respond to load-related feedback in the same way by prolonging the muscle activity resisting the load. We hypothesized that for ...
Tochigi Yuki - - 2006
BACKGROUND: Passive ankle stability under weight-bearing conditions has been found to depend substantially on the role of the articular surface geometry. In the present study, it was hypothesized that, in the ankle under axial loading, contact-stress changes in response to alterations of external load involve reproducible and specific patterns to ...
Gelfand Bradley D - - 2006
PURPOSE: To determine the heterogeneity of the time-varying shear stress profiles in the human carotid bifurcation, a region prone to atherosclerosis. MATERIALS AND METHODS: Lagrangian bicubic interpolation of phase-contrast MRI images was used to determine the shear stress profiles for three adult healthy male volunteers. Frequency spectra for the common ...
Attwells Renee L - - 2006
Military personnel are required to carry heavy loads whilst marching; this load carriage represents a substantial component of training and combat. Studies in the literature mainly concentrate on physiological effects, with few biomechanical studies of military load carriage systems (LCS). This study examines changes in gait and posture caused by ...
Arampatzis Adamantios - - 2007
The purpose of the present study was to investigate whether the mechanical properties (i.e. force strain relationship) of the triceps surae tendon and aponeurosis relate to the performed sport activity in an intensity-dependent manner. This was done by comparing sprinters with endurance runners and subjects not active in sports. Sixty-six ...
Gründer Wilfried - - 2006
In T2-weighted MRI images joint cartilage can appear laminated. The multilaminar appearance is visualized as zones of different intensity. This appearance is based on the dipolar interaction of water molecules within cartilage zones of different collageneous network structures. Therefore, the MR visualization of zones of anisotropic arrangement of the collagen ...
McKinley Todd O - - 2006
Cartilage biosynthetic transduction and injury characteristics have been shown to be particularly sensitive to changes in contact stress rates. This study investigated incongruity-associated changes in contact stress rates that resulted from an articular surface stepoff of the distal tibia in human cadaveric ankles. Ten human cadaveric ankles were subjected to ...
Cooper G - - 2007
The research aims to carry out a detailed analysis of the loads applied by the ambulance workers when loading/unloading ambulance stretchers. The forces required of the ambulance workers for each system are measured using a load cell in a force handle arrangement. The process of loading and unloading is video ...
Markolf Keith L - - 2006
PURPOSE: Our purpose was to evaluate the role of the posteromedial (PM) bundle of the native posterior cruciate ligament (PCL) in restraining posterior tibial translation and the effects of sectioning of the PM bundle on PCL forces. METHODS: The PCL's femoral origin was mechanically isolated by use of a cylindrical ...
Davenport Paul W - - 2007
The relationship between detection threshold of inspiratory resistive loads and the peaks of the respiratory-related evoked potential (RREP) is unknown. It was hypothesized that the short-latency and long-latency peaks of the RREP would only be elicited by inspiratory loads that exceeded the detection threshold. The detection threshold for inspiratory resistive ...
Li Cheng - - 2006
Cartilage mechanical properties are typically tested at the macroscale. To demonstrate the ability of nanoindentation to characterize in situ articular cartilage properties at the tissue scale, we investigated the local structure-property relationships of intact articular cartilage of a normal rabbit metacarpophalangeal joint. We calculated the mechanical parameters of stiffness, S, ...
Santos Marcio J - - 2007
An unloading reaction has been characterized as a modified flexor reflex (FR), in which the standing subjects decrease the load on the stimulated foot and increase the load on the contralateral side, but, without withdrawal of the stimulated foot. Different behavioral circumstances have been shown to modulate this reflex. It ...
Azéma Emilien - - 2006
By means of two-dimensional contact dynamics simulations, we analyze the vibrational dynamics of a confined granular layer in response to harmonic forcing. We use irregular polygonal grains allowing for strong variability of solid fraction. The system involves a jammed state separating passive (loading) and active (unloading) states. We show that ...
Nickel J C JC University of Nebraska Medical Center College of Dentistry, Department of Growth and Development, PO Box 683740, Lincoln, NE 68583-0755, USA. - - 2006
Mechanical fatigue-related degeneration of the temporomandibular joint (TMJ) disc may be promoted by tractional forces. This study tested the hypotheses that tractional forces following static loading of the TMJ disc: (1) increase with compressive strain at the start of movement, and (2) are velocity-dependent during movement. Sixty-four porcine discs received ...
Tanaka Eiji - - 2007
The role of the periodontal ligament (PDL) is to support the tooth during function and resist external forces applied to it. The dominant vertical component of these forces is associated with shear in the PDL. Little information, however, is available on the dynamic behavior of the PDL in shear. Therefore, ...
Wolf Amela - - 2007
Articular cartilage in vivo experiences the effects of both cell-regulatory proteins and mechanical forces. This study has addressed the hypothesis that the frequency of intermittently or continuously applied mechanical loads is a critical parameter in the regulation of chondrocyte collagen biosynthesis. Cyclic compressive pressure was applied intermittently to bovine articular ...
Zink Attila J - - 2006
This study examined the changes in peak power, ground reaction force and velocity with different loads during the performance of the parallel squat movement. Twelve experienced male lifters (26.83 +/- 4.67 years of age) performed the standard parallel squat, using loads equal to 20, 30, 40, 50, 60, 70, 80, ...
Brodke Darrel S - - 2006
BACKGROUND: Anterior plates provide stability following decompression and fusion of the cervical spine. Various plate designs have emerged, and they include static plates with fixed-angle screws, rotationally dynamic plates that allow the screws to toggle in the plate, and translationally dynamic plates that allow the screws to both toggle and ...
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