Search results for "Biomedical engineering"

2021

Purpose: Physical activity promotes a positive physical self-image, but less is known about whether the positive effect covers the general self-evaluation of adolescent appearance. This study aimed to further explore the associations between physical activity and body-esteem in Finnish adolescents, via a country-representative cross-sectional study design. Methods: The data for the study were drawn from the Finnish component of the Health Behaviour in School-aged Children (HBSC) study (2014), using surveys from 15-year-old adolescents (n=1956, mean age 15.8 years) from 122 schools. Self-evaluations of body or appearance were measured by the Body-Esteem Scale for Adolescents and Adults (BESA…

A morphology-based approach to the evaluation of atrial fibrillation organization.

2007

Comparison of region of interest segmentation methods for video-based heart rate measurements

2018

International audience; Conventional contact photoplethysmography (PPG) sensors are not suitable in situations of skin damage or when unconstrained movement is required. As a consequence, remote photoplethysmography (rPPG) has recently emerged because it provides remote physiological measurements without expensive hardware and improves comfort for long-term monitoring. RPPG estimation methods use the spatially averaged RGB values of pixels in a Region Of Interest (ROI) to generate a temporal RGB signal. The selection of ROI is a critical first step to obtain reliable pulse signals and must contain as many skin pixels as possible with a low percentage of non-skin pixels. In this paper, we ex…

Numerical simulation of transcatheter mitral valve replacement: The dynamic implication of LVOT obstruction in the valve-in-ring case.

2022

Transcatheter mitral valve replacement (TMVR) has been used for “off-label” treatment when annuloplasty band ring for mitral repair fails. However, the complex anatomy and function of the mitral valve may lead to fatal complications as a result of the left ventricular outflow tract (LVOT) obstruction in TMVR. We report the structural and hemodynamic response of LVOT obstruction resulting from TMVR with the Edwards SAPIEN 3 Ultra (S3) device. We modified the original Living Heart Human Model (LHHM) to account for a failed mitral valve with an annuloplasty band ring and simulated the cardiac beating condition in the setting of S3 device implantation. Findings demonstrated a high dynamic behav…

Fabrication of elastomeric scaffolds with curvilinear fibrous structures for heart valve leaflet engineering

2014

Native semi-lunar heart valves are composed of a dense fibrous network that generally follows a curvilinear path along the width of the leaflet. Recent models of engineered valve leaflets have predicted that such curvilinear fiber orientations would homogenize the strain field and reduce stress concentrations at the commissure. In the present work, a method was developed to reproduce this curvilinear fiber alignment in electrospun scaffolds by varying the geometry of the collecting mandrel. Elastomeric poly(ester urethane)urea was electrospun onto rotating conical mandrels of varying angles to produce fibrous scaffolds where the angle of fiber alignment varied linearly over scaffold length.…

Quantifying multidimensional control mechanisms of cardiovascular dynamics during multiple concurrent stressors

2021

Heartbeat regulation is achieved through different routes originating from central autonomic network sources, as well as peripheral control mechanisms. While previous studies successfully characterized cardiovascular regulatory mechanisms during a single stressor, to the best of our knowledge, a combination of multiple concurrent elicitations leading to the activation of different autonomic regulatory routes has not been investigated yet. Therefore, in this study, we propose a novel modeling framework for the quantification of heartbeat regulatory mechanisms driven by different neural routes. The framework is evaluated using two heartbeat datasets gathered from healthy subjects undergoing p…

Remote Photoplethysmography measurement using constrained ICA

2017

Remote Photoplethysmography (rPPG) is a technique that consists in estimating physiological parameters such as heart rate from live or recorded video sequences taken by conventional camera or even webcams. This technique is increasingly used in many application fields thanks to its simplicity and affordability. The basic idea is that the arterial blood flow shows regularity due to the heartbeat. This regularity is manifested by very small periodic variations in the color of the skin, which can be isolated and quantified by signal and image processing methods. In this context, Independent Component Analysis (ICA) is largely used to separate the signal due to arterial flow from signals from o…

<title>Optical non-invasive monitoring of skin blood pulsations</title>

2005

Time resolved detection and analysis of the skin backscattered optical signals (remission photoplethysmography or PPG) provide rich information on skin blood volume pulsations and can serve for reliable cardiovascular assessment. The single- and multi-channel PPG concepts are discussed in this work. Simultaneous data flow from several body locations allows one to study the heartbeat pulse wave propagation in real time and evaluate the vascular resistance. Portable single-, dual- and four-channel PPG monitoring devices with special software have been designed for real-time data acquisition and processing. The clinical studies confirmed their potential in the monitoring of heart arrhythmias, …

Does shoe heel-to-toe drop have an influence on performance in downhill trail running?

2019

Trail running (TR) is characterized by sequences of uphill and downhill performed in a natural environment. Recently, studies investigated performance factors specific to TR. During a full race of ...

A heuristic model-based approach for compensating wind effects in ski jumping.

2021

Wind influences the jump length in ski jumping, which raises questions about the fairness. To counteract the wind problem, the International Ski Federation has introduced a wind compensation system in 2009: time-averaged wind velocity components tangential to the landing slope are obtained from several sites along the landing slope, and these data are used in a linear statistical model for estimating the jump length effect of wind. This is considered in the total score of the ski jump. However, it has been shown that the jump length effect estimates can be inaccurate and misleading. The present manuscript introduces an alternative mathematical wind compensation approach that is based on an …