Search results for "Biomedical"
showing 10 items of 2328 documents
Autologous Iliac Bone Graft Compared with Biphasic Hydroxyapatite and Calcium Sulfate Cement for the Treatment of Bone Defects in Tibial Plateau Frac…
2019
Background Bone-graft substitutes are commonly used for the augmentation of traumatic bone defects in tibial plateau fractures. However, their clinical performance compared with that of autologous bone-grafting, the gold standard in bone defect reconstruction, still remains under debate. This study investigates the differences in quality of life, pain, and radiographic outcomes in the treatment of tibial plateau fracture-associated bone defects with either autologous bone grafts or a bioresorbable hydroxyapatite and calcium sulfate cement (CERAMENT BONE VOID FILLER [CBVF]; BONESUPPORT). Methods In this study, 135 patients with acute depression and split-depression fractures of the proximal …
Ultrastructural study by backscattered electron imaging and elemental microanalysis of biomaterial-to-bone interface and mineral degradation of bovin…
2012
Objectives The aim of this study was to perform an ultrastructural study of the bone-to-biomaterial interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using bovine xenografts (Endobon®) in 15 clinical cases. Materials and methods Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX). Results No clin…
Force-, EMG-, and elasticity-velocity relationships at submaximal, maximal and supramaximal running speeds in sprinters.
1986
The relationships between ground reaction forces, electromyographic activity (EMG), elasticity and running velocity were investigated at five speeds from submaximal to supramaximal levels in 11 male and 8 female sprinters. Supramaximal running was performed by a towing system. Reaction forces were measured on a force platform. EMGs were recorded telemetrically with surface electrodes from the vastus lateralis and gastrocnemius muscles, and elasticity of the contact leg was evaluated with spring constant values measured by film analysis. Data showed increases in most of the parameters studied with increasing running speed. At supramaximal velocity (10.36 +/- 0.31 m X s-1; 108.4 +/- 3.8%) the…
Do Stretch Durations Affect Muscle Mechanical and Neurophysiological Properties?
2016
International audience; The aim of the study was to determine whether stretching durations influence acute changes of mechanical and neurophysiological properties of plantar flexor muscles. Plantar flexors of 10 active males were stretched in passive conditions on an isokinetic dynamometer. Different durations of static stretching were tested in 5 randomly ordered experimental trials (1, 2, 3, 4 and 10×30-s). Fascicle stiffness index, evoked contractile properties and spinal excitability (Hmax/Mmax) were examined before (PRE), immediately after (POST0) and 5 min after (POST5) stretching. No stretch duration effect was recorded for any variable. Moreover, whatever the stretching duration, st…
Electromechanical delay in skeletal muscle under normal movement conditions.
1979
Electromechanical delays (EMD), the time from onset of EMG activity to change in acceleration or deceleration of the forearm, were studied in concentric and eccentric contractions of biceps and triceps brachii muscles. Horizontal flexion and extension movements were performed at varying speeds by 10 subjects. EMD time in concentric contractions for biceps was 41 +/- 13 ms and for triceps was 26 +/- 11 ms and was not influenced by the velocity of the movement. In eccentric contractions at the slow velocity the biceps EMD time was 38 +/- 13 ms and shortened to 28 +/- 10 ms at the faster velocity. The eccentric triceps EMD, however, was not significantly altered by movement velocity and averag…
Immobilisation of linear and cyclic RGD-peptides on titanium surfaces and their impact on endothelial cell adhesion and proliferation
2011
Functional coatings on titanium vascular stents and endosseous dental implants could probably enhance endothelial cell (EC) adhesion and activity with a shortening of the wound healing time and an increase of peri-implant angiogenesis during early bone formation. Therefore, the role of the structure of linear and cyclic cell adhesive peptides Arg-Gly-Asp (l-RGD and c-RGD) on differently pre-treated titanium (Ti) surfaces (untreated, silanised vs. functionalised with l- and c-RGD peptides) on EC cell coverage and proliferation was evaluated. After 24 h and after 3 d, surface coverage of adherent cells was quantifi ed and an alamarBlue® proliferation assay was conducted. After 24 h, l-RGD mod…
Neutrophil‐mediated enhancement of angiogenesis and osteogenesis in a novel triple cell co‐culture model with endothelial cells and osteoblasts
2017
Repair and regeneration of critical‐sized bone defects remain a major challenge in orthopaedic and craniomaxillofacial surgery. Until now, attempts to bioengineer bone tissue have been hindered by the inability to establish proper angiogenesis and osteogenesis in the tissue construct. In the present study, we established a novel triple cell co‐culture model consisting of osteoblasts, endothelial cells, and neutrophils and conducted a systematic investigation of the effects of neutrophils on angiogenesis and osteogenesis. Neutrophils significantly increased angiogenesis in the tissue construct, evidenced by the formation of microvessel‐like structures with an extensive lattice‐like, stable t…
EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels.
2001
Muscle fiber conduction velocity (CV) may be affected by the level of voluntary activation and by the diameter of the fiber. Both the frequency component of the electromyography (EMG) power spectrum, such the as median frequency (MF) or mean power frequency, and the duration of muscle compound action potential to single supramaximal electrical impulse (maximal M-wave) may be related to CV. The aim of the present study was to examine how changes in the activation level in lengthening and in shortening conditions would affect the EMG power spectrum during voluntary effort, and compare them to changes in M-wave shape in similar conditions. Ten male subjects performed eccentric and concentric k…
Agreement of white-to-white measurements with the IOLMaster 700, Atlas 9000, and Sirius systems
2018
Current advances in ocular surgery require the evaluation of differences in automated white-to-white (WTW) measurements between systems. We aim to analyze three different commonly used devices in clinical practice: the IOLMaster 700, the Atlas 9000, and the Sirius.Ninety right eyes of ninety healthy subjects were included. Measurements of WTW distances were taken with each device for all subjects in the same session and by the same observer. Statistical comparison was carried out by means of the rANOVA procedure and the Bonferroni post-hoc test. In addition, the Bland-Altman analysis was applied in order to perform pairwise comparisons.Average WTW values obtained by the IOLMaster 700, the A…
The effect of fatigue on store and re-use of elastic energy in slow and fast types of human skeletal muscle
1986
Stretch-shortening exercises are characterized by enhancement of performance when compared to the work output performed in shortening conditions. There is evidence that fast subjects are unable to re-use great amounts of elastic energy during stretch-shortening cycles performed with slow stretching speed and large stretching length. In the present study, 14 subjects possessing different fibre types in m. vastus lateralis performed vertical jumps with and without preliminary countermovement and with large angular displacement and slow stretching speed The jumping tests were executed before and immediately after fatigue induced by short intense exercises (60 s of continuous rebound jumping). …