Search results for "tissues"
showing 10 items of 271 documents
Fast PET Scan Tumor Segmentation Using Superpixels, Principal Component Analysis and K-Means Clustering
2018
Positron Emission Tomography scan images are extensively used in radiotherapy planning, clinical diagnosis, assessment of growth and treatment of a tumor. These all rely on fidelity and speed of detection and delineation algorithm. Despite intensive research, segmentation remained a challenging problem due to the diverse image content, resolution, shape, and noise. This paper presents a fast positron emission tomography tumor segmentation method in which superpixels are extracted first from the input image. Principal component analysis is then applied on the superpixels and also on their average. Distance vector of each superpixel from the average is computed in principal components coordin…
Hip muscle function in patients with symptomatic femoroacetabular impingement
2014
Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint, which could lead to hip pain and functional disability. Aim of this thesis was to investigate hip muscle function in patients with a symptomatic FAI. Hip muscle function was first investigated before patients underwent any surgical treatment for managing FAI. It was shown that they present with reduced hip muscle strength (i.e., muscle weakness), probably due to hip muscle inhibition. Nevertheless, hip muscle weakness was not associated with exaggerated hip muscle fatigue. Hip muscle strength recovery was then evaluated in a series of patients after hip arthroscopy to treat FAI. These patients demonstrated a g…
Role of polysialic acid (PSA) in the control of food intake and body weight
2013
Hypothalamus plays a major role in the regulation of energy homeostasis by the presence of neural circuits controlling food intake. These circuits are plastic and can be rewired during adulthood. We hypothesized that synaptic plasticity can occur during physiological conditions. We have shown that synaptic contact on hypothalamic anorexigen POMC neurons are rewired in mouse upon high fat diet (HFD). This synaptic process is mandatory to adjust energy intake and requires the glycan PSA (polysialic acid). PSA promotes synaptic plasticity in the brain by the weakening of cell-to-cell interaction by addition on NCAM (neural cell adhesion molecule). We hypothesized that a defect in brain synapti…
Comparison of the structure of the plasma-facing surface and tritium accumulation in beryllium tiles from JET ILW campaigns 2011-2012 and 2013-2014
2019
In this study, beryllium tiles from Joint European Torus (JET) vacuum vessel wall were analysed and compared regarding their position in the vacuum vessel and differences in the exploitation conditions during two campaigns of ITER-Like-Wall (ILW) in 2011-2012 (ILW1) and 2013-2014 (ILW2) Tritium content in beryllium samples were assessed. Two methods were used to measure tritium content in the samples - dissolution under controlled conditions and tritium thermal desorption. Prior to desorption and dissolution experiments, scanning electron microscopy and energy dispersive x-ray spectroscopy were used to study structure and chemical composition of plasma-facing-surfaces of the beryllium sampl…
Unsupervised tissue classification of brain MR images for voxel-based morphometry analysis
2016
In this article, a fully unsupervised method for brain tissue segmentation of T1-weighted MRI 3D volumes is proposed. The method uses the Fuzzy C-Means (FCM) clustering algorithm and a Fully Connected Cascade Neural Network (FCCNN) classifier. Traditional manual segmentation methods require neuro-radiological expertise and significant time while semiautomatic methods depend on parameter's setup and trial-and-error methodologies that may lead to high intraoperator/interoperator variability. The proposed method selects the most useful MRI data according to FCM fuzziness values and trains the FCCNN to learn to classify brain’ tissues into White Matter, Gray Matter, and Cerebro-Spinal Fluid in …
Expression of the Acetylcholine Receptor α-Subunit Gene is Associated with Paraneoplastic Myasthenia Gravis in Mixed Thymoma
2000
Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies against the acetylcholine receptor (AChR) at the neuromuscular junction [1]. The muscular AChR has been extensively characterized [2], but the etiology of MG is still obscure. Whether the muscular AChR or another (auto)antigen plays a role during the initiation of MG is unknown [3]. The muscular AChR is a pentameric ion channel composed of four different subunits. The α-subunit contains the acetylcholine binding site and the main epitopes recognized by MG autoantibodies [2]. The human muscle AChR α-subunit exists as two isoforms, P3A- and P3A+ [4]. This is a result of alternative splicing of the P3A exon located betwee…
A non-linear stochastic approach of ligaments and tendons fractional-order hereditariness
2020
Abstract In this study the non-linear hereditariness of knee tendons and ligaments is framed in the context of stochastic mechanics. Without losing the possibility of generalization, this work was focused on knee Anterior Cruciate Ligament (ACL) and the tendons used in its surgical reconstruction. The proposed constitutive equations of fibrous tissues involves three material parameters for the creep tests and three material parameters for relaxation tests. One-to-one relations among material parameters estimated in creep and relaxations were established and reported in the paper. Data scattering, observed with a novel experimental protocol used to characterize the mechanics of the tissue, w…
Sex difference in Double Iron ultra-triathlon performance
2013
Abstract Background The present study examined the sex difference in swimming (7.8 km), cycling (360 km), running (84 km), and overall race times for Double Iron ultra-triathletes. Methods Sex differences in split times and overall race times of 1,591 men and 155 women finishing a Double Iron ultra-triathlon between 1985 and 2012 were analyzed. Results The annual number of finishes increased linearly for women and exponentially for men. Men achieved race times of 1,716 ± 243 min compared to 1,834 ± 261 min for women and were 118 ± 18 min (6.9%) faster (p < 0.01). Men finished swimming within 156 ± 63 min compared to women with 163 ± 31 min and were 8 ± 32 min (5.1 ± 5.0%) faster (p < …
Sex difference in race performance and age of peak performance in the Ironman Triathlon World Championship from 1983 to 2012
2012
Abstract Background The fastest Ironman race times in ‘Ironman Hawaii’ were achieved in very recent years. This study investigated the change in sex difference in both race performance and the age of peak performance across years in the top ten athletes for split disciplines and overall race time in the ‘Ironman Hawaii’ between 1983 and 2012. Methods Changes in split times, overall race times, and age of athletes across years for the top ten overall and the fastest swimmers, cyclists, and runners were investigated using regression analyses and analyses of variance. Results Between 1983 and 2012, the overall top ten men and women finishers improved their swimming (only men), cycling, running…
Performance and Age of the Fastest Female and Male 100-km Ultramarathoners Worldwide From 1960 to 2012
2015
International audience; The purpose of this cross-sectional study was to investigate the change in 100-km running performance and in the age of peak performance for 100-km ultramarathoners. Age and running speed of the annual fastest women and men in all 100-km ultramarathons held worldwide between 1960 and 2012 were analyzed in 148,017 finishes with 18,998 women and 129,019 men using single, multivariate, and nonlinear regressions. Running speed of the annual fastest men increased from 8.67 to 15.65 km.h(-1) and from 8.06 to 13.22 km.h(-1) for the annual fastest women. For the annual 10 fastest men, running speed increased from 10.23 ± 1.22 to 15.05 ± 0.29 km.h(-1) (p < 0.0001) and for the…