Search results for "Biomechanic"
showing 10 items of 706 documents
Why ruminating ungulates chew sloppily: Biomechanics discern a phylogenetic pattern.
2019
Altres ajuts: "Beatriu de Pinos" 2014 - BP-A 00048 There is considerable debate regarding whether mandibular morphology in ungulates primarily reflects phylogenetic affinities or adaptation to specific diet. In an effort to help resolve this debate, we use three-dimensional finite element analysis (FEA) to assess the biomechanical performance of mandibles in eleven ungulate taxa with well-established but distinct dietary preferences. We found notable differences in the magnitude and the distribution of von Mises stress between Artiodactyla and Perissodactyla, with the latter displaying lower overall stress values. Additionally, within the order Artiodactyla the suborders Ruminantia and Tylo…
Grass leaves as potential hominin dietary resources
2018
Discussions about early hominin diets have generally excluded grass leaves as a staple food resource, despite their ubiquity in most early hominin habitats. In particular, stable carbon isotope studies have shown a prevalent C4 component in the diets of most taxa, and grass leaves are the single most abundant C4 resource in African savannas. Grass leaves are typically portrayed as having little nutritional value (e.g., low in protein and high in fiber) for hominins lacking specialized digestive systems. It has also been argued that they present mechanical challenges (i.e., high toughness) for hominins with bunodont dentition. Here, we compare the nutritional and mechanical properties of gra…
Impact loading history modulates hip fracture load and location : A finite element simulation study of the proximal femur in female athletes
2018
Sideways falls impose high stress on the thin superolateral cortical bone of the femoral neck, the region regarded as a fracture-prone region of the hip. Exercise training is a natural mode of mechanical loading to make bone more robust. Exercise-induced adaptation of cortical bone along the femoral neck has been previously demonstrated. However, it is unknown whether this adaption modulates hip fracture behavior. The purpose of this study was to investigate the influence of specific exercise loading history on fall-induced hip fracture behavior by estimating fracture load and location with proximal femur finite element (FE) models created from magnetic resonance images (MRI) of 111 women w…
The use of accelerometry to evaluate the BMX cycling starting hill. Effect of the Q-Ring™ on the acceleration profile
2020
Accelerometers are becoming popular in sport performance, as they are easy to wear, affordable, and usable in the field. Eccentric chainrings have been commercialised to improve pedalling performance, but little is known about their possible effects in the first pedal strokes (PS) of maximal sprint starts. To analyse the effects of the Q-Ring chainring (Q) on pedalling mechanics and performance in the BMX starting hill, 12 Spanish-National-Team BMX athletes performed 3 maximal sprints comparing Q vs No-Q. Time was measured in the first three meters. Acceleration output was registered with a triaxial 6 g accelerometer (200 Hz) in the first four PS. Discrete time, acceleration and statistical…
Real-time biomechanical modeling of the liver using Machine Learning models trained on Finite Element Method simulations
2020
[EN] The development of accurate real-time models of the biomechanical behavior of different organs and tissues still poses a challenge in the field of biomechanical engineering. In the case of the liver, specifically, such a model would constitute a great leap forward in the implementation of complex applications such as surgical simulators, computed-assisted surgery or guided tumor irradiation. In this work, a relatively novel approach for developing such a model is presented. It consists in the use of a machine learning algorithm, which provides real-time inference, trained on tens of thousands of simulations of the biomechanical behavior of the liver carried out by the finite element me…
Human Achilles tendon glycation and function in diabetes
2016
Diabetic patients have an increased risk of foot ulcers, and glycation of collagen may increase tissue stiffness. We hypothesized that the level of glycemic control (glycation) may affect Achilles tendon stiffness, which can influence gait pattern. We therefore investigated the relationship between collagen glycation, Achilles tendon stiffness parameters, and plantar pressure in poorly ( n = 22) and well ( n = 22) controlled diabetic patients, including healthy age-matched (45–70 yr) controls ( n = 11). There were no differences in any of the outcome parameters (collagen cross-linking or tendon stiffness) between patients with well-controlled and poorly controlled diabetes. The overall effe…
Exercise Biomechanics and Physiology.
2021
Biomechanics was defined by Hatze in 1974 as the study of the movement of living things using the science of mechanics [...]
Low-energy extracorporeal shockwave therapy (ESWT) improves metaphyseal fracture healing in an osteoporotic rat model.
2017
Purpose As result of the current demographic changes, osteoporosis and osteoporotic fractures are becoming an increasing social and economic burden. In this experimental study, extracorporeal shock wave therapy (ESWT), was evaluated as a treatment option for the improvement of osteoporotic fracture healing. Methods A well-established fracture model in the metaphyseal tibia in the osteoporotic rat was used. 132 animals were divided into 11 groups, with 12 animals each, consisting of one sham-operated group and 10 ovariectomized (osteoporotic) groups, of which 9 received ESWT treatment. Different energy flux intensities (0.15 mJ/mm2, 0.35 mJ/mm2, or 0.55 mJ/mm2) as well as different numbers o…
Effect of chondroitin sulphate on synovitis of knee osteoarthritic patients.
2017
Abstract Objective To evaluate by ultrasonography the effect of chondroitin sulfate (CS) on synovitis in patients with knee osteoarthritis (KOA). To collaborate in the understanding of the biochemical mechanisms involved in the synovial inflammation process. Methods Randomized, single-blind, controlled trial involving 70 patients with primary KOA treated for 6 months with CS or acetaminophen (ACT). Evaluation of KOA status at baseline, 6 weeks, 3 and 6 months included: ultrasonography to assess synovitis (following the OMERACT expertise group definition), visual analogue scale and Lequesne index to measure pain and function, and ELISA to quantify inflammatory mediators in serum and synovial…
On the growth and form of cortical convolutions
2016
International audience; The rapid growth of the human cortex during development is accompanied by the folding of the brain into a highly convoluted structure1-3. Recent studies have focused on the genetic and cellular regulation of cortical growth4-8, but understanding the formation of the gyral and sulcal convolutions also requires consideration of the geometry and physical shaping of the growing brain9-15. To study this, we use magnetic resonance images to build a 3D-printed layered gel mimic of the developing smooth fetal brain; when immersed in a solvent, the outer layer swells relative to the core, mimicking cortical growth. This relative growth puts the outer layer into mechanical com…