Search results for "Weight-Bearing"

Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility.

2017

In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The…

Effect of cyclic loading on fracture strength and microleakage of a quartz fiber dowel with different adhesive, cement and resin core material combin…

2010

Background: This study evaluated the performance of different adhesive-cement-core combinations coupled with quartz fiber dowels after cyclic loading and fracture strength tests and assessed the microleakage using dye penetration method. Methods: Forty maxillary canines (n=10 per group) were restored with fiber dowels (Quartz fiber DT Light Post) and four adhesive-cement-core material combinations [(Group 1: All-Bond 2+C&B (root) / All-Bond 2+Biscore (core); Group 2: All-Bond 2+Bisfil 2B (root) / All-Bond 2+Bisfil 2B (core); Group 3: Scotchbond 1+RelyX ARC (root) / Scotchbond 1+Supreme (core); Group 4: RelyX Unicem (root) / Scotchbond 1+Filtek Supreme (core)]. The specimens were initially c…

Reconstruction of the weight-bearing surface of the foot with free flaps

2015

Plantar pressure and EMG activity of simulated and actual ski jumping take-off

2001

Plantar pressures and activation of the four muscles (VL - vastus lateralis, GL - gluteus, TA - tibialis anterior and GA - lat. gastrocnemius) were measured from ten ski jumpers under simulated laboratory conditions with training shoes (Lab TS) and with jumping boots (Lab JB) as well as in actual hill jumping conditions (Hill). The most significant differences between measured conditions were found in muscle activation patterns and plantar pressures prior to take-off. The centrifugal force due to the curvature of the inrun under actual hill jumping conditions caused extra pressure under the fore and rear parts of the feet (P<0.001) and therefore higher activation in all muscles (P<0.001 for…

Locking Reconstruction Double Plating of Distal Humeral Fractures: How Many Screws in the Distal Ulnar Column Segment in A3 Fracture Provide Superior…

2009

Objectives: Two 90-degree configurations of locking reconstruction plates with different numbers of screws in the distal ulnar column segment of distal extra-articular humeral fractures with metaphyseal comminution (A3) were biomechanically investigated. Methods: Eight pairs of fresh-frozen human humeri were used. For paired comparison, the humeri were divided into 2 randomized groups. In both groups, double-plate osteosyntheses with locking reconstruction plates were performed in 90-degree configurations. In group 1, the posteriorly placed radial column plate exceeded the capitellum and the ulnar column plate extended into the ulnar sulcus. The ulnar plate was molded around the medial epic…

The synovial joints of the human foot.

2007

The human foot is considered an organ with an assortment of tissues with different morphological characteristics and well defined limits, but effectively has a simple functionality when static that becomes extremely complex when in movement. Its complex structure, comprised of an elastic and resistant skin covering a bone framework, joints, muscles, tendons, veins and nerves, can be compared to an efficient mechanical assembly. After a long and extraordinary evolutive journey, the human foot has undergone numerous changes to perfect its function; it has lost most of its grabbing function whilst gaining new characteristics that have ultimately allowed the modern man to stand upright. The com…

Variability and Symmetry of Force Platform Variables in Maximum-Speed Running in Young and Older Athletes

2010

Eighteen young (23 ± 4 yr) and 25 older (70 ± 4 yr) male sprinters were examined for ground reaction force (GRF) and temporal-spatial variables. The data were collected during maximum-speed phase, and variability and symmetry indices were calculated from a total of 8 steps. There was little variation (CV &lt; 6%) in vertical and resultant GRF and kinematic variables, while impact loading had high variability (CV: 10–21%). Overall, the pattern of variability was similar in both groups. Yet, a small but significant age-related increase in CV was evident in horizontal GRFs. There was a variable-specific asymmetry between legs but it was not related to leg dominance. No age differences existed …

Cardiorespiratory Responses Induced by Various Military Field Tasks

2014

Typical military tasks include load carriage, digging, and lifting loads. To avoid accumulation of fatigue, it is important to know the energy expenditure of soldiers during such tasks. The purpose of this study was to measure cardiorespiratory responses during military tasks in field conditions. Unloaded (M1) and loaded (M2) marching, artillery field preparation (AFP), and digging of defensive positions (D) were monitored. 15 conscripts carried additional weight of military outfit (5.4 kg) during M1, AFP, and D and during M2 full combat gear (24.4 kg). Absolute and relative oxygen uptake (VO2) and heart rate (HR) of M1 (n = 8) were 1.5 ± 0.1 L min(-1), 19.9 ± 2.7 mL kg(-1) min(-1) (42 ± 7%…

The limits of visual mass perception

2009

The theory of direct perception suggests that observers can accurately judge the mass of a box picked up by a lifter shown in a point-light display. However, accurate perceptual performance may be limited to specific circumstances. The purpose of the present study was to systematically examine the factors that determine perception of mass, including display type, lifting speed, response type, and lifter's strength. In contrast to previous research, a wider range of viewing manipulations of point-light display conditions was investigated. In Experiment 1, we first created a circumstance where observers could accurately judge lifts of five box masses performed by a lifter of average strength…

Bone Trauma Causes Massive but Reversible Changes in Spinal Circuitry.

2016

Abstract Bone fracture with subsequent immobilization of the injured limb can cause complex regional pain syndrome (CRPS) in humans. Mechanisms of CRPS are still not completely understood but bone fracture with casting in mice leads to a similar post-traumatic inflammation as seen in humans and might therefore be an analog to human CRPS. In this article we report behavioral and spinal electrophysiological changes in mice that developed swelling of the paw, warming of the skin, and pain in the injured limb after bone fracture. The receptive field sizes of spinal neurons representing areas of the hind paws increased after trauma and recovered over time—as did the behavioral signs of inflammat…