Search results for "Biomedical engineering"
showing 10 items of 2020 documents
Effect of footwear on plantar flexor fine-wire electromyography activity in walking
2019
Compared to barefoot walking, walking in footwear seems to alter plantar flexor electromyography (EMG) activity, vertical and horizontal ground reaction forces (Sacco, Akashi, & Hennig, 2010), ankle kinematics and the time of peak activity (Sacco et al., 2010). However, study results are inconsistent regarding the magnitude and direction of these changes. Magnetic resonance imaging showed high inter-individual variability in muscle metabolic activity during walking, suggesting individual-specific activation patterns (Kolk et al., 2015). Additionally, little is known about the role of toe flexors such as flexor hallucis longus (FHL) in walking.
Comparison of frequency domain measures based on spectral decomposition for spontaneous baroreflex sensitivity assessment after Acute Myocardial Infa…
2021
Abstract The objective of this study is to present a new method to assess in the frequency domain the directed interactions between the spontaneous variability of systolic arterial pressure (SAP) and heart period (HP) from their linear model representation, and to apply it for studying the baroreflex control of arterial pressure in healthy physiological states and after acute myocardial infarction (AMI). The method is based on pole decomposition of the model transfer function and on the following evaluation of causal measures of coupling and gain from the poles associated to low frequency (0.04−0.15 Hz) oscillatory components. It is compared with traditional non-causal approaches for the sp…
Analysis of in-silico body surface P-wave integral maps show important differences depending on the connections between coronary sinus and left atrium
2016
The electrical connections between the atrial coronary sinus (CS) and the left atrial (LA) myocardium have an effect on the overall atrial activation pattern and the P-wave morphology. In this study, we use our validated multi-scale 3D human atrial-torso model to elucidate which electro-anatomical configuration of connections between CS and LA more accurately reproduces a set of body surface P-wave integral maps (BSPiM) acquired in the clinic. We performed atrial biophysical simulations by pacing in distal and proximal LA sites. The corresponding in-silico BSPiM were then computed and compared with published clinical patterns obtained from patients. Important differences in BSPiM were obser…
Dynamic 4D Blood Flow Representation in the Aorta and Analysis from Cine-MRI in Patients
2007
International audience; Abstract: Natural evolution of aortic disease is characterized by a diameter increase that can result in aortic dissection or rupture. Currently the evaluation of risk of rupture or dissection is based on the size of the aorta. However, this parameter is not always relevant and it appears necessary to define new parameters. In this perspective, 3D velocity imaging acquired with ECG gated velocity-encoded cine-MRI allows the aortic blood flow study. As the acquired images are not directly usable, the present study proposes a 4D-representation Of aortic blood flow in order to optimize the visualization of the particularities of non-laminar flow within the aorta. Image …
Pancreatic islets from non-heart beating donor pig: Two-layer preservation method in an in vitro porcine model
2011
Purpose Pancreata from non-heart beating donors could represent an unlimited source of islets if their cell viability can be efficiently preserved during the time necessary to process the organs by the use of a better solution of preservation compared to the classic University of Wisconsin solution. The aim of this study was to determine whether it is possible to obtain functioning “alive islets” from non-heart-beating donors by comparing, on a porcine model, the classic “UW ice-store” method with a two-layer cold storage method (TLM) using oxygenated Perfluorocarbons (PFC) and UW. Methods Whole pancreata were harvested from 20 NHBDs female pigs with similar characteristics and preserved fo…
Ischemic type biliary lesions in histidine-tryptophan-ketoglutarate (HTK) preserved liver grafts.
2006
Ischemic type biliary lesions lead to considerable morbidity following orthotopic liver transplantation. The exact pathogenesis is unknown. One major hypothesis is that insufficient perfusion of the arterial vessels of the biliary tree, especially under perfusion with the high viscous University of Wisconsin solution, might be responsible for ischemic type biliary lesions. Due to low viscosity, HTK solution is reported to have a lower incidence of biliary complications. However, there is no data concerning ischemic type biliary lesions in HTK preserved livers. In this paper we report our results after orthotopic liver transplantation with special regard to ischemic type biliary lesions in …
Computational fluid dynamics simulation to evaluate aortic coarctation gradient with contrast-enhanced CT
2014
Coarctation of aorta (CoA) is a narrowing of the aorta leading to a pressure gradient (Delta P) across the coarctation, increased afterload and reduced peripheral perfusion pressures. Indication to invasive treatment is based on values of maximal (systolic) trans-coarctation Delta P. A computational fluid dynamic (CFD) approach is herein presented for the non-invasive haemodynamic assessment of Delta P across CoA. Patient-specific CFD simulations were created from contrast-enhanced computed tomography (CT) and appropriate flow boundary conditions. Computed Delta P was validated with invasive intravascular trans-CoA pressure measurements. Haemodynamic indices, including pressure loss coeffic…
Response to the comments on “Effects of high intensity aquatic resistance training on body composition and walking speed in women with mild knee oste…
2017
This article has no abstract. nonPeerReviewed
Ventricular Fibrillation detection using time-frequency and the KNN classifier without parameter extraction
2017
[ES] Este trabajo propone la detección de FV y su discriminación de TV y otros ritmos cardiacos basándose en la representación tiempo-frecuencia del ECG y su conversión en imágen como entrada a un clasificador de vecinos más cercanos (KNN) sin necesidad de extracción de parámetros adicionales. Tres variantes de datos de entrada al clasificador son evaluados. Los resultados clasifican la señal en cuatro clases diferentes: ’Normal’ para latidos con ritmo sinusal, ’FV’ para fibrilación ventricular, ’TV’ para taquicardia ventricular y ’Otros’ para el resto de ritmos. Los resultados para detección de FV mostraron 88,27% de sensibilidad y 98,22% de especificidad para la entrada de imágen equivale…
Eating disorders on the web: risks and resources.
2009
Our work is aimed at exploring the recent literature data on web sites, forums, and blogs, which promote eating disorders as normal life styles and their implication in the changes of the psychopatology of such disorders. We also want to understand whether new technologies have an impact in the course of the disorders or, on the other hand, whether they can also represent an instrument for searching help or information about them. The search strategy included a search of PsycINFO, Medline, and Ovid databases to identify research reports about pro-ana sites and their implication on the course of anorexia using the following key words: pro-ana, thinspiration, anorexia-web, online help eating …