Search Results
Results 401 - 450 of 778
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Basso N - - 2002
Normal loading strains of 200-2000 (mu)epsilon to bone result in bending forces, generating mechanical stretch and pressure gradients in canaliculi that drive extracellular fluid flow, resulting in stress on the membranes of osteocytes, lining cells, and osteoblasts. Under excess loading, as well as during unloading (e.g., microgravity, bed rest), the ...
Mackey D C DC School of Kinesiology, Simon Fraser University, - - 2002
An experiment was performed to characterise the movement kinematics and the electromyogram (EMG) during rhythmic voluntary flexion and extension of the wrist against different compliant (elastic-viscous-inertial) loads. Three levels of each type of load, and an unloaded condition, were employed. The movements were paced at a frequency of 1 Hz ...
Søgaard K - - 2001
BACKGROUND: Biomechanical models have been used frequently to estimate the load on the low back and the lower extremities during occupational work tasks. The shoulder region has received much less attention although this area is a common site of work-related musculoskeletal disorders. OBJECTIVE: The aim of the present study was ...
Heiss D G - - 2001
STUDY DESIGN: Mixed, repeated measures design. OBJECTIVES: To determine if previous experience with loads of similar weight influences the anticipatory lifting force and postural adjustments during the squat lift. To examine a multijoint, functional task for coordination between stability and movement. To determine if lifting unexpected loads results in trunk ...
van der Burg J C - - 2001
Sudden, unexpected loading on the low back is associated with a high incidence of low back pain. Experiments in which sudden loading was applied during standing revealed increased compression forces on the spine and increased trunk angle, which may cause injury to the spine and hence explain this association. During ...
Otto J K - - 2001
Despite their increasing clinical use, mobile-bearing total knee replacements have not been well characterized biomechanically. An experimental and finite element analysis was done to assess the mobility and contact mechanics of a widely used rotating platform total knee replacement. Parameters that varied were axial load, condylar load allocation, flexion angle, ...
Jin M - - 2001
Chondrocytes are known to sense and respond to mechanical and physicochemical stimuli by multiple regulatory pathways, including upstream signaling, transcription, translation, posttranslational modifications, and vesicular transport. Due to the complexity of identifying the biophysical phenomena that occur during cartilage loading in vivo, the regulatory mechanisms that govern chondrocyte mechanotransduction are ...
Herzog W - - 2001
STUDY DESIGN: Twenty asymptomatic volunteers each received three spinal manipulative treatments to the thoracic spine. The treatments consisted of a straight posterior-to-anterior high-speed, low-amplitude thrust to the transverse process of T3-T10 using a reinforced hypothenar contact. All treatments were given by a full-time practicing clinician with 3 years of experience. ...
Komatsu K - - 2001
Tooth-periodontal ligament-bone segments were cut in the form of rectangular prisms (1.5 mm wide, 0.65 mm thick, and long enough to allow anchorage of the bone and tooth-end portions in a stretching jig) from the mandibular incisors of 10 rabbits. The experimental set-up enabled simultaneous recording, on video, of the ...
Beek M - - 2001
While the movability of the human temporomandibular joint is great, the strains and stresses in the cartilaginous structures might largely depend on the position of the mandible with respect to the skull. This hypothesis was investigated by means of static three-dimensional finite element simulations involving different habitual condylar positions. Furthermore, ...
Li K W - - 2001
During skeletal development, growth, and maturation, gradual changes in the material properties and physical dimensions of cartilage occur under the influence of mechanical loading. The objective of the current study was to compare glycosaminoglyean biosynthesis and cell proliferation in fetal, calf, and adult bovine cartilage explants, isolated from defined depths ...
Wu S P - - 2001
This study used the psychophysical approach to examine the effects of container width, the presence or absence of container handles, and different load-carrying frequencies and distances on the maximum acceptable weight carried and the resulting response (heart rate and rating of perceived exertion) by well-conditioned males for a 1-h work ...
Araujo M M - - 2001
PURPOSE: The purpose of this study was to compare the biomechanical characteristics of metallic and polymeric fixation systems using a 3-dimensional skull model to simulate clinical conditions of maxillary advancement and loading. MATERIAL AND METHODS: Standard titanium, prebent titanium, and resorbable plates and mesh were applied to surgically altered polyurethane ...
Bijker K E - - 2001
PURPOSE: The purpose of the present study was to compare delta efficiencies of running with cycling, while several factors that can possibly influence delta efficiency were excluded. METHODS: Twelve subjects performed a submaximal running and cycling test on subsequent days. Delta efficiencies of running and cycling were compared at equal ...
Hatzitaki V V Department of Physical Education and Sports Sciences, Aristotle University, 540 06 Thessaloniki, Greece. - - 2001
This study employed the paradigm of asymmetric limb loading during bilateral arm reaching to examine the motor system's ability to independently organize the discrete movement of both upper limbs to equidistant targets when one of the limbs is loaded under specific timing constraints. The loading procedure involved attaching two different ...
Moalli M R - - 2001
Utilizing an in vivo model of trabecular bone formation, we demonstrated the temporal and spatial activation of pp125(FAK) in response to specific mechanical load stimuli. Bone chambers equipped with hydraulic actuators were aseptically inserted into each proximal tibial metaphysis of adult, male dogs under general anesthesia. The load stimulus consisted ...
Schibye B - - 2001
OBJECTIVE: Compare the mechanical load on the low back and shoulders during pushing and pulling a two-wheeled container with the load during lifting and carrying the same amount of waste. BACKGROUND: Only little is known about risk factors and mechanical loads during push/pull operations. DESIGN: A complete 2(3) factor push/pull ...
Heki K - - 2001
Distinct periodic variations with annual frequencies are often found in the time series of continuous Global Positioning System (GPS) site coordinates in northeastern Japan. They show maximum arc-normal contraction of a few millimeters as well as maximum subsidence of 1 to 2 centimeters, both in March. In northeastern Japan, it ...
Jantarat J - - 2001
OBJECTIVE: The purpose of this study was to investigate the extent of progressive cuspal displacement during prolonged occlusal loading (either continuous or cyclic) and delayed cuspal recovery following removal of the load. METHODS: Extracted maxillary premolars with extensive MOD cavity plus endodontic access were subjected to an occlusal load applied ...
Baldissera F F Istituto di Fisiologia Umana II, Università degli Studi, Milano, Italy. - - 2001
The role of kinaesthetic afferences in controlling coupling of voluntary oscillation of the hand and foot, both in-phase and anti-phase, was investigated by modifying the mechanical properties of one of the two segments (the hand) with applied inertial or elastic loads. Loads consisted of a lead disk, rotating coaxially with ...
Aruin A S AS Department of Physical Therapy, University of Illinois, Chicago, - - 2001
The main purpose of the present study has been to find an answer to the question: Can the subject generate anticipatory postural adjustments (APAs) when a predictable postural perturbation occurs in the absence of a voluntary action? Answering this question would allow us to distinguish between two competing hypotheses on ...
Elder S H - - 2001
As part of a program of research aimed at determining the role of mechanical forces in connective tissue differentiation, we have developed a model for investigating the effects of dynamic compressive loading on chondrocyte differentiation in vitro. In the current study, we examined the influence of cyclic compressive loading of ...
Dechant H E HE University of Vienna, Biocenter, Institute of Zoology, Wien, - - 2001
Striving towards an in depth understanding of stimulus transformation in arthropod tactile hairs, we studied the mechanical events associated with tactile stimulation. A finite element model was developed taking a tarsal tactile hair of the spider Cupiennius salei as an example. Considering hair diameter, wall thickness, and curvature, the hair ...
Gan R Z - - 2001
The middle ear as a levered vibrating system for sound transmission from the external to the inner ear is affected by changes in ossicular chain mass. Mass loading of the ossicles may impair ossicular dynamics and sound transmission to the inner ear. It is incumbent on otologic surgeons and researchers ...
Joiner G A - - 2001
Matrix degradation and proteoglycan loss in articular cartilag eare features of early osteoarthritis. To determine the effect of matrix degradation and proteoglycan loss on ultrasound propagation in cartilage, we used papain and interleukin-1alpha to degrade the matrix proteoglycans of human and bovine cartilage samples, respectively. There is also minor collagen ...
Haugstvedt J R - - 2001
In order to perform cadaveric biomechanical studies of the human forearm and distal radio-ulnar joint, a dynamic simulator has been constructed. The device is based upon a Plexiglas frame, to which the ulna is secured in a vertical orientation and the humerus in a horizontal orientation. The hand is secured ...
Tausz M - - 2001
Most environmental stress conditions promote the production of potentially toxic active oxygen species in plant cells. Plants respond with changes in their antioxidant and photoprotective systems. Antioxidants and pigments have been widely used to measure these responses. Because trees are exposed to multiple man-made and natural stresses, their responses are ...
Chu I T IT Department of Orthopaedic Surgery, The Union Memorial Hospital, Baltimore, Maryland 21218, - - 2001
The goal of this study was to determine if the application of muscle forces (simulating the dynamic phase of the midstance part of gait) had an effect on flatfoot deformity. We created a flatfoot model in each of seven cadaver foot specimens by grasping the Achilles, peroneus longus, peroneus brevis, ...
Beek M - - 2001
The cartilaginous intra-articular disc of the human temporomandibular joint shows clear anteroposterior variations in its morphology. However, anteroposterior variations in its tissue behavior have not been investigated thoroughly. To test the hypothesis that the mechanical properties of fresh human temporomandibular joint discs vary in anteroposterior direction, we performed dynamic indentation ...
Robling A G - - 2001
A number of in vivo skeletal loading models have been developed to test specific hypotheses addressing the key mechanical and biochemical signals involved in bone's adaptive response to loading. Exercise protocols, osteotomy procedures, loading of surgically implanted pins, and force application through the soft tissues are common approaches to alter ...
Cronin J - - 2001
The influence of contraction type and movement type on power output of the upper body musculature was investigated across loads of 30-80% 1RM. Twenty seven males (21.9+/-3.1 years, 89.0+/-12.5 kg, 86.32+/-13.66 kg 1RM) of an athletic background but with no weight training experience in the previous six months volunteered for ...
Fries Svensson H H Liljeholmens VC, Intraprenaden, Huddinge University Hospital, - - 2001
Ergonomic measures have been found to reduce load-related trouble from the neck-and-shoulders during visual display unit (VDU) work. An important question is the height at which the screen should be placed to give the lowest possible load. Should it be placed at eye-level or below? The aim of the present ...
Magnusson S P - - 2001
1. The present investigation measured the load-displacement and stress-strain characteristics of the proximal and distal human triceps surae aponeurosis and tendon in vivo during graded voluntary 10 s isometric plantarflexion efforts in five subjects. 2. During the contractions synchronous real-time ultrasonography of aponeurosis displacement, electromyography of the gastrocnemius, soleus and ...
Mitchell S B - - 2001
An apparatus was developed to apply user-specified displacements to biomaterial samples in culture. The device allowed cyclic waveforms of bandwidth 0 Hz to 20 Hz to be applied under physiologic thermal (37.5 degrees C) and [CO2] (5%) conditions. For a 0 Hz to 20 Hz bandwidth signal similar in shape ...
Koga Y - - 2001
A low noise and highly stable microwave exciter system has been built for Cs atomic frequency standards using a tunable sapphire-loaded cavity oscillator (SLCO), which works at room temperature. This paper discusses the successful implementation of a control system for locking the SLCO to a long-term reference signal and reports ...
Palumbo Nicole - - 2001
PURPOSE: The purpose of this research was to determine if standing dynamic balance was affected by carrying a backpack. SUBJECTS: Data was obtained from 50 healthy college students. MATERIALS AND METHODS: Limits of stability was assessed using the Smart Equitest Balance Master System(R). Reaction time, movement velocity, end point excursion, ...
Filaire M - - 2001
The influence of various modes of carrying a load of 16 kg (15.69 DaN) on the static positioning of the pelvic girdle and the thoracic and lumbar segments of the spine was examined in seven male subjects. The displacement of cutaneous markers attached to easily palpable skeletal landmarks was recorded ...
Wallace A L - - 2001
Thermal denaturation of collagen in ligament tissue has the potential to enhance arthroscopic shoulder stabilization. Previous studies have shown that laser energy produces significant capsular shortening without alteration of viscoelastic properties, but little information is available on the effects of radio frequency electrothermal energy. We assessed the acute effects of ...
Willey Marc S. - - 2001
This study used two dimensional biomechanical analysis to examine the effects of back belts and lifting load on selected lifting kinematics during a simulated patient transfer. A human manikin placed in a sitting position was attached to a customized lifting apparatus which controlled the lifting load and direction of the ...
Rassler B - - 2000
OBJECTIVES: The present study was performed to detect the interactions between breathing and the postural motor control of the fingers. A previous study revealed a scattering in the intraindividual motor responses which resembled a grouping. It is hypothesized to result from the influence of breathing. METHODS: Torque impulses and torque ...
Slobounov S - - 2000
OBJECTIVES: The present study was designed to obtain additional data regarding the differential influence of kinematic parameters and different nominal force levels upon components of movement-related cortical potentials (MRP) during index finger flexion. METHODS: The absolute nominal force level of discrete movements was varied while the rate of force development ...
Trickey W R - - 2000
The deformation behavior and mechanical properties of articular chondrocytes are believed to play an important role in their response to mechanical loading of the extracellular matrix. This study utilized the micropipette aspiration test to measure the viscoelastic properties of chondrocytes isolated from macroscopically normal or end-stage osteoarthritic cartilage. A three-parameter ...
Gorb S S Biochemistry Department, Max-Planck-Institute of Developmental Biology, Tübingen, Germany. - - 2000
Natural releasable attachment systems of insect legs, where attachment-detachment performances are often very fast, seem to be optimized to get a maximum of real contact to the substratum. Tarsi of Tettigonia viridissima bear flexible attachment pads with unusual ultrastructural architecture of the cuticle. The indentation of the attachment pads was ...
Kernozek T W TW Department of Physical Therapy, University of Wisconsin-La Crosse, Health Science Center, 54601, USA. - - 2000
In-shoe measurement systems allow the clinician and researcher to examine the loading parameters within the shoe. This study sought to investigate the test retest reliability and speed effects of in-shoe loading parameters using the Pedar System (Novel GMBH Munich) during slow treadmill running. The results indicated good to excellent test ...
Barnes H A - - 2000
We report the results of experiments carried out on the stress relaxation of slightly stretched human hair. The results show that human hair is viscoelastic, and that when quickly extended to a moderate degree (0.5-6.5%) and held, the force generated will fall to half its original value in about 15 ...
Pfaeffle H J - - 2000
The objective of our study was to measure 3-dimensional force vectors (magnitude and direction) acting in the forearm when load is applied to the hand and to measure the actual force in the interosseous ligament (IOL). Fourteen cadaveric forearms were loaded to 136 N of compression while special load cells ...
Markolf K L - - 2000
Forces transmitted through the distal ulna and proximal radius, relative motion between the radial head and capitellum, and measurements of tissue strain and local fiber tension within the central band of the interosseous membrane were recorded as cadaveric forearms were loaded axially through the wrist. With the elbow in valgus ...
Anglin C - - 2000
OBJECTIVE: To conduct a pilot study to characterize the hand loads, arm joint angles and external moments corresponding to five activities of daily living demanding of the shoulder, for healthy subjects over 50 years of age. DESIGN: The tasks were sit-to-stand, stand-to-sit, cane walking, lifting a 5 kg box with ...
Merrifield R - - 2000
Deliberate or accidental initiation of explosives can produce a range of potentially damaging fire and explosion effects. Quantification of the consequences of such effects upon the surroundings, particularly on people and structures, has always been of paramount importance. Information on the effects on flora and fauna, however, is limited, with ...
Lavender S A - - 2000
STUDY DESIGN: Ten men and eight women participated in a repeated-measures experiment in which sudden loads were applied unexpectedly to a container held in the hands. Three independent variables were investigated: lifting belt use, preload, and load symmetry. OBJECTIVES: To determine whether a lifting belt would help protect the spine ...
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