Search results for "valve"
showing 6 items of 576 documents
RED BLOOD CELL DISTRIBUTION WIDTH PREDICTS MORBIDITY AND MORTALITY AFTER AORTIC VALVE REPLACEMENT
2014
Objective: Red blood cell distribution width (RDW), is a measurement of the size variation as well as an erythrocyte heterogeneity index (i.e., anysocytosis). used in combination with the mean corpuscular volume for anemia diagnosis. However, it is emerging as an useful predictor biomarker of mortality and morbidity of cardiovascular diseases. However, until now no literature data there are about the RDW role in predicting mortality after aortic valve replacement (AVR). Thus, in this pilot study biological significance of elevated RDW values in early outcome following AVR was evaluated Methods: We enrolled 75 patients (mean age 73.5 ±7.9 years) subjected to AVR and/ or not co temporally to …
A MICRO-ARCHITECTURAL BASED STRUCTURAL MODEL FOR ELASTOMERIC ELECTROSPUN SCAFFOLDS FOR HEART VALVE TISSUE ENGINEERING
2010
BACKGROUND. Improving how scaffold architectures affect cell morphology, metabolism, phenotypic expression, and predicting mechanical behaviors, are crucial goals in the development of engineered heart valve scaffolds. Studies are required to elucidate how the fibrous microstructure translates into specific tissue (or meso-scale) level mechanical behavior. Deterministic structural models can quantify how key structures contribute to the mechanical response as a function of bulk deformation across multiple scales, as well as provide a better understanding of cellular mechanical response to local micro-structural deformations. An appropriate representative volume element (RVE) size was determ…
Sand clams of Ganzirri marine coastal lagoon in Messina (Italy). Extraction and ICP-MS analysis
2008
This paper studies the possible forms or phases of heavy metals in sediments of a marine coastal lagoon, called Ganzirri, located in the Sicilian coast of the Messina’s strait by using sequential extraction. To reduce the extraction time of the Tessier method, the last step of speciation was carried out by mineralization in a microwave oven. Here we report the results of the distribution of As, Be, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, Tl, V and Zn, in four fractions of sediments samples and the concentration of the same metals in clams. This study looked at three bivalve mollusc species, Tapes decussates, Chamelea gallina and Cardium edule, raised in the sediment considered and discussed the…
3D Printing and Computational Modeling for the Evaluation of LVOT obstruction in Transcatheter Mitral Valve Replacement
2022
Transcatheter mitral valve replacement (TMVR) is an emerging alternative treatment for those patients not qualified for surgery. However, TMVR can determine an obstruction of the left ventricular outflow tract (namely, neo-LVOT) induced by the transcatheter heart valve (THV) displacing the native mitral valve leaflet towards the myocardial wall. This condition can lead to haemodynamic impairment and ultimately patient death. We sought to predict the neo-LVOT obstruction by first developing patient-specific simulations of the THV deployment and then comparing predictions with post-TMVR diagnostic images and 3D printed human models. Using pre-TMVR computed-tomography (CT) imaging, patient-spe…
Analysis of requirements for valve accuracy and repeatability in high efficiency digital displacement motors
2018
Traditional variable displacement piston machines achieve high efficiency when operating at high displacements, but struggle with poor efficiency at low displacements. The pistons are connected to high pressure and low pressure in conjunction with the output shaft position and the displacement is changed by changing the piston stroke, resulting in almost constant friction, leakage, and compressibility losses independent of displacement. In digital displacement machines, the rotary valve is replaced by two fast switching on/off valves connected to every cylinder. By controlling the fast switching on/off valves, the cylinders can be controlled individually and friction, leakage and compressib…
Porównanie stopnia uszkodzenia mięśnia sercowego po zastosowaniu kardioplegii krwistej i krystaloidowej u pacjentów poddanych zabiegowi izolowanej wy…
2016
Wstęp: Kardioplegina jest środkiem używanym do tymczasowego zatrzymywania czynności elektromechanicznej serca w zabiegach kardiochirurgicznych. Jest to roztwór o wysokiej zawartości jonów potasu podawany do tętnic wieńcowych w postaci zmieszanej z krwią pacjenta z oksygenatora (kardioplegina krwista) lub w postaci roztworu krystaloidowego (kardioplegina krystaloidowa). W dotychczasowych badaniach w większości wykazano wyższość kardiopleginy krwistej nad krystaliczną w operacjach pomostowania aortalno-wieńcowego (CABG). Celem niniejszego badania było sprawdzenie, czy u pacjentów poddanych izolowanemu zabiegowi wymiany zastawki aortalnej (AVR), podobnie jak w przypadku pacjentów poddanych CAB…