The Structure of porous building materials

Porous materials such as stone, brick, concrete and wood are far from being the simple materials their extensive use suggests. Understanding of their structure is essential, therefore, if reliable prediction is to be made of their response to various conditions of exposure.Aussi disponible en fran\ue7ais : Structure des mat\ue9riaux poreux de constructionPeer reviewed: NoNRC publication: Ye

In vitro cytotoxicity of dental adhesive systems under simulated pulpal pressure

International audienc

0413: Hemodynamic and regurgitation after TAVI. An in-vitro study

IntroductionObservations of EDWARDS SAPIEN prosthesis (ED SA) once deployed in vivo, shows a frequent elliptic geometry, which can cause inadequate transvalvular hemodynamic and the occurence of valvular regurgitation (intra and/or para).ObjectivesThis study aims to quantify in vitro, hemodynamic and valvular regurgitation of ED SA in circular and elliptic deployment conditions.MethodA pulsed simulator reproducing the human circulation was used. ED SA 23 and 26 were implanted in circular annulus with increasing diameter (18, 20, 22mm for the size 23 and 21, 23, 25mm for 26) and in 4 elliptic annulus for each size prosthesis (3 annulus with increasing Eccentricity Index (EI) at 0.17, 0.26, 0.33 starting to a small fixed diameter and 1 with the smallest and biggest diameters of circular annulus). The Effective Orifice Area (EOA) was calculated by the continuity equation and mean transvalvular gradient (TVG) were obtained by Doppler. The performance index (PI=100x(EOA/annulus area) was calculated. The ultrasound allowed the research of regurgitation, quantified by flow measurement.ResultsThe highest TVG were observed for circular annulus 18 and 20mm, respectively 17.7 and 12.2mmHg, which was correlated with the lowest EOA (1.27 and 1.44cm2). We observed a mismatch leaflets-stent for annulus 18 with plicature of leaflets. Hemodynamic parameters and mean PI (48.5 vs 43.2) were better with elliptic geometry than circular. No significant intraprosthetic regurgitation was observed. Just 1 paraprosthetic regurgitation occured for the ED SA 26 in the elliptic annulus with largest EI.ConclusionHemodynamic parameters of ED SA obtained in vitro with elliptic geometry appear to be better than those with circular. A “leaflets-stent mismatch” can occur in the case of undersizing in annulus with smaller area

EFFECT OF VALVE OVERSIZING ON LEAFLET BENDING STRESS IN THE COREVALVE: AN IN VITRO STUDY

66th Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC), Washington, DC, MAR 17-19, 2017International audienceno abstrac

CLINICAL STUDY OF THE IMPACT OF PREEXISTING PATIENT-PROSTHESIS MISMATCH ON VALVE-IN-VALVE PERFORMANCE

66th Annual Scientific Session and Expo of the American-College-of-Cardiology (ACC), Washington, DC, MAR 17-19, 2017International audienceno abstrac