Césarienne | EPFL Graph Search

alt=|vignette|371x371px|Un accouchement par césarienne. La césarienne est une intervention chirurgicale visant à extraire un enfant de l'utérus maternel par incision de la paroi abdominale et utérine. La césarienne est pratiquée depuis des millénaires mais l'invention de la suture utérine est datée de 1882 et est attribuée à Max Sänger. Longtemps la césarienne fut opérée sur des femmes mortes, et ce depuis la Rome antique, pour tenter de sauver un enfant possiblement viable car assez développé physiologiquement. Étymologie Le mot « césarienne » dérive du latin caesar, du verbe caedere (« couper », « inciser »), terme utilisé pour le nom d'une loi de la Rome antique, la Lex Caesarea, qui oblige à pratiquer une césarienne sur une femme enceinte morte ou sur le point de mourir. Une étymologie populaire, qui a pour origine un passage de Pline l'Ancien, la lie à la naissance de Jules César. Mais il est fort peu probable qu'Aurelia Cotta, la mère de Jules César, ait pu survivr

Virtual reality enabled building-data management through the combination of a fully integrated IFC-BIM model and an IoT-based building management system

Sergi Aguacil Moreno, Jean-Philippe Bacher, Laurent Deschamps, Sebastian Duque Mahecha, Alexandre Denis Stoll

Professionals involved in building construction and monitoring increasingly implement new practices made available by Building Information Modelling (BIM), Virtual Reality (VR) and the Internet of Things (IoT). In spite of numerous efforts, most methods integrating BIM and IoT rely on Application Programming Interfaces (APIs) related to Closed Source Software (CSS), which practically exclude the basic BIM Industry Foundation Classes (IFC) standard. Within the fewer methods actively using the IFC data model to VR-enhanced interfaces, we can observe the loss of crucial IFC information. This article describes a workflow of a BIM-IFC to VR-enabled data management definition, articulating a Building Management Systems' (BMS) database or, as an alternative, an IoT system. This workflow is presented through four phases (model making, device inventory, protocol setting, and real-time VR interaction), which correspond to the actual sections of the information flow that we have successfully tested.

2021

Reflective optical objective

Jürgen Brugger, Victor Javier Cadarso Busto, Davor Kosanic, Bastien Rachet

The present invention relates to a reflective optical objective (1) comprising: —a first reflecting element (3) including a front surface (3a) and a hack surface (3b), the front surface (3a) including a convex reflecting surface (11); and —a second reflecting element (5) including a concave reflecting surface (13) facing the convex reflecting surface (11) of the first reflecting element (3), the second reflecting element (5) including a transmissive section (7) permitting electromagnetic radiation to pass through the concave reflecting surface (13) of the second reflecting element (5) to the first reflecting element (3). The reflective optical objective (1) is characterised in that the reflective optical objective (1) includes a carrier material (9) embedding at least the front surface (3a) of the first reflecting element (3) and defining the distance (d) between the first (3) and second (5) reflecting elements.

2015

Effect of intimal shear and cyclic strech on arterial segments perfused in vitro

Veronica Gambillara

Hemodynamics have crucial role in the control of vascular tone, in the regulation of arterial remodeling, and in the production of mediators that maintain arterial function. Changes in hemodynamics forces induce profound alterations in vascular cell metabolism and function, in the extracellular matrix, and in smooth muscle cell (SMC) phenotypes, all being part of vessel wall remodeling. Vessel wall remodeling plays a key role in arterial wall homeostasis but also in the initiation and development of arterial disease. This aim of this work is to study the effects of two distinct biomechanical stimuli, oscillatory shear and cyclic stretch on vessel wall function. Our 71 investigation is performed using an improved in vitro artery perfusion system, which allows to study the exact contribution of each biomechanical stimulus on isolated arterial segments, where the biological cell responses of endothelial and SMCs, and the extracellular matrix interactions are well preserved. The present thesis is divided into two main sections. The first part focuses on the effects of oscillatory shear stress on arterial segments, a mechanism presumed to be involved in the localization and initiation of atherosclerotic plaques. The second section investigates the influence of reduced cyclic stretch on the arterial wall, a procedure that is occurring in arterial stiffening. In the first and second papers, we examined the effects of three different shear stress conditions on the endothelium, SMC, and arterial wall responses, in porcine carotid arteries perfused in vitro for three days. We demonstrated that oscillatory shear stress, which is usually present in plaque-prone areas, decreased the bradykinin-induced vasorelaxation after 3 days of perfusion. The endothelial dysfunction was correlated to an impaired endothelial nitric oxide synthase gene expression and bradykinin-mediated activation. The potential lack of nitric oxide production and/or bioavailability observed in arteries exposed to oscillatory shear stress may also be the cause of the start of matrix turnover. Expression and activation of matrix metalloproteinase-2 and-9 were increased in arteries exposed to oscillatory shear, suggesting that this type of shear stress triggers a remodeling process. This part of the study provides a new insights on the role of shear stress in the control of arterial function and supports the hypothesis that oscillatory shear stress is a determining factor predisposing the arterial wall to atherosclerosis. The third paper focuses on the effects of cyclic stretch on vascular smooth muscle function, phenotype and wall remodeling. Arteries were wrapped by an external banding, which drastically decreased compliance and therefore the cyclic stretch. Arteries were perfused for one day under a unidirectional shear stress (6±3 dyn/cm2) in combination with a mean pressure of 80 mmHg and a pulse pressure of +/-10 mmHg. We demonstrated that exposure to reduced cyclic stretch induced a rapid modulation of SMC phenotype which was combined with a decrease in norepinephrine-induced vasocontraction. SMC dedifferentiation was associated to a decrease of plasminogen activator inhibitor-1 expression, which, combined with enhanced matrix metalloproteinase-2, may promote wall remodeling and SMC migration. These findings give a further approach into possible consequences of an arterial stiffening on large vessel wall patho-physiology.

EPFL2005

Effect of intimal shear and cyclic strech on arterial segments perfused in vitro

Veronica Gambillara

EPFL2005