Search results for "Biomechanical"
showing 10 items of 524 documents
Enhanced In Situ Availability of Aphanizomenon Flos-Aquae Constituents Entrapped in Buccal Films for the Treatment of Oxidative Stress-Related Oral D…
2019
In recent years, the key role of oxidative stress in pathogenesis of oral diseases has been emphasized and the use of antioxidant agents has been encouraged. Aphanizomenon flos-aquae (AFA) is a unicellular blue-green alga with antioxidant and anti-inflammatory properties. The aim of this study was the formulation and characterization of mucoadhesive thin layer films loaded with AFA, finalized to the treatment of oxidative stress (OS)-related oral diseases. First, to enhance the bioavailability of AFA constituents, the raw food grade material was appropriately treated by a high frequency homogenization able to disrupt cell walls. Thus, Eudragit®
Computer Modeling for the Prediction of Thoracic Aortic Stent Graft Collapse
2011
OBJECTIVE: To assess the biomechanical implications of excessive stent protrusion into the aortic arch in relation to thoracic aortic stent graft (TASG) collapse by simulating the structural load and quantifying the fluid dynamics on the TASG wall protrusion extended into a model arch. METHODS: One-way coupled fluid-solid interaction analyses were performed to investigate the flow-induced hemodynamic and structural loads exerted on the proximal protrusion of the TASG and aortic wall reconstructed from a patient who underwent traumatic thoracic aortic injury repair. Mechanical properties of a Gore TAG thoracic endoprosthesis (W. L. Gore and Assoc, Flagstaff, Ariz) were assessed via experimen…
Constitutive modeling of ascending thoracic aortic aneurysms using microstructural parameters.
2016
Ascending thoracic aortic aneurysm (ATAA) has been associated with diminished biomechanical strength and disruption in the collagen fiber microarchitecture. Additionally, the congenital bicuspid aortic valve (BAV) leads to a distinct extracellular matrix structure that may be related to ATAA development at an earlier age than degenerative aneurysms arising in patients with the morphological normal tricuspid aortic valve (TAV). The purpose of this study was to model the fiber-reinforced mechanical response of ATAA specimens from patients with either BAV or TAV. This was achieved by combining image-analysis derived parameters of collagen fiber dispersion and alignment with tensile testing dat…
Factors affecting peak impact force during soccer headers and implications for the mitigation of head injuries
2020
It has been documented that up to 22% of all soccer injuries are concussions. This is in part due to players purposely using their head to direct the ball during play. To provide a more complete understanding of head trauma in soccer athletes, this study characterized the effects of four soccer ball characteristics (size, inflation pressure, mass, velocity) on the resulting peak impact force as it relates to the potential for incurring neurophysiological changes. A total of six hundred trials were performed on size 4 and 5 soccer balls as well as a novel lightweight soccer ball. Impact force was measured with a force plate and ball velocity was determined using motion capture. These data we…
Directionnalité graphique et dominance manuelle : une perspective développementale et interculturelle
2012
In the present work, we try to provide some understanding about the factors underlying the directional tendencies, by examining the impact of biomechanical constraints and cultural habits on directionality in graphic movements. French and Syrian subjects, children and adults, were compared in six experiments in order, to put in evidence the cognitive and psychomotor differences caused by the fact that the Eastern and Western cultures oppose on the directionality of writing and reading habits, and that the two hands are opposite in the directionality by adopting movements determined by biomechanical constraints. Likewise, this comparison allowed us to determine the relative strength of these…
The Application of Machine Learning Algorithms to the Analysis of Electromyographic Patterns From Arthritic Patients
2009
The main aim of our study was to investigate the possibility of applying machine learning techniques to the analysis of electromyographic patterns (EMG) collected from arthritic patients during gait. The EMG recordings were collected from the lower limbs of patients with arthritis and compared with those of healthy subjects (CO) with no musculoskeletal disorder. The study involved subjects suffering from two forms of arthritis, viz, rheumatoid arthritis (RA) and hip osteoarthritis (OA). The analysis of the data was plagued by two problems which frequently render the analysis of this type of data extremely difficult. One was the small number of human subjects that could be included in the in…
Biodynamic behavior of the trunk and the abdomen during whole-body vibration
1989
Vibration strain may be defined as the sum of all reactions of the human being to vibration exposure. This also includes the biomechanical behavior of particular parts of the body. Knowledge about these reactions is necessary in the field of occupational health and ergonomics. Biomechanical models, experimental methods, and results are presented. It can be shown that under vibration exposure with different conditions (body posture, vibration direction), the body parts are in resonance at varying frequencies, mainly in a low frequency range.
Do More Highly Organized Collagen Fibrils Increase Bone Mechanical Strength in Loss of Mineral Density After One-Year Running Training?
1999
The aim of this study was to evaluate the effects of long-term running training on the structural properties of bone. Ten beagle dogs ran according to a strenuous progressive program (up to 40 km/day) for 1 year. At the end of the training program, there was a significant reduction in bone mineral density (up to 9.7%) in the vertebrae of the runner dogs as compared with 10 sedentary control dogs. Polarized light microscopy of the vertebral trabecular bone, however, displayed proportionally higher retardation values of the collagen network of the runner dogs than of the sedentary dogs, suggesting a reorganization in a more parallel manner in the collagen fibrils. The concentration and cross-…
A test of the effort equalization hypothesis in children with cerebral palsy who have an asymmetric gait.
2022
Healthy people can walk nearly effortlessly thanks to their instinctively adaptive gait patterns that tend to minimize metabolic energy consumption. However, the economy of gait is severely impaired in many neurological disorders such as stroke or cerebral palsy (CP). Moreover, self-selected asymmetry of impaired gait does not seem to unequivocally coincide with the minimal energy cost, suggesting the presence of other adaptive origins. Here, we used hemiparetic CP gait as a model to test the hypothesis that pathological asymmetric gait patterns are chosen to equalize the relative muscle efforts between the affected and unaffected limbs. We determined the relative muscle efforts for the ank…
The gait is less stable in children with cerebral palsy in normal and dual-task gait compared to typically developed peers
2021
There is limited evidence about gait stability and its alteration by concurrent motor and cognitive tasks in children with cerebral palsy (CP). We examined gait stability and how it is altered by constrained cognitive or motor task in CP and their typically developed (TD) controls. Gait kinematics were recorded using inertial-measurement units (IMU) from 18 patients with hemiplegia (13.5 +/- 2.4 years), 12 with diplegia (13.0 +/- 2.1 years), and 31 TD controls (13.5 +/- 2.2 years) during unconstrained gait, and motor (carrying a tray) and cognitive (word naming) task constrained gait at preferred speed (similar to 400 steps/task). Step duration, its standard deviation and refined-compound-m…