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Direct flow valve

Victor Kamoen, Milad El Haddad, Marc De Buyzere, Tine De Backer, Frank Timmermans
AIMS: We recently reported the feasibility of the average pixel intensity (API) method for grading mitral regurgitation (MR) in a heterogeneous MR population. Since mitral valve prolapse (MVP) is an important cause of primary MR, we more specifically investigated the feasibility of the API method and the MR flow dynamics in patients with MVP. METHODS: Transthoracic echocardiography was performed by a single operator in consecutive MVP patients (n=112). MR was assessed using the API method, color Doppler, vena contracta width (VCW), effective regurgitant orifice area (PISA-EROA) and regurgitant volume (PISA-RV)...
May 1, 2018: International Journal of Cardiology
Agnieszka A Ksiazek, Laura Frese, Petra E Dijkman, Bart Sanders, Sarah E Motta, Benedikt Weber, Simon P Hoerstrup
Data on in vitro engineered "off the shelf" matrices support the concept of endogenous cellular repopulation driving the graft's remodeling via immune-mediated response. This seems important to further accelerate the cell reconstitution and may play a crucial role when mononuclear cells are used. Nevertheless, studies on decellularized xenogeneic grafts showed only limited host cell repopulation post-implantation. This study aims at a systematic comparison of reseeding methods (dripping, injection, bathing in a cell suspension and combined puncturing-dripping method) to define the most efficient technique enhancing recellularization of tissue engineered vascular matrices (patches, vessels, small diameter and standard size valves) prior implantation...
March 2, 2018: Acta Biomaterialia
Yifei Jin, Yangyang Shen, Jun Yin, Jin Qian, Yong Huang
Stimuli-responsive hydrogels and/or composite hydrogels have been of great interest for various printing applications including four-dimensional (4D) printing. While various responsive hydrogels and/or composite hydrogels have been found to respond to given stimuli and change shapes as designed, the fabrication of three-dimensional (3D) structures from such responsive hydrogels is still a challenge due to their poor 3D printability, and most of responsive material-based patterns are two-dimensional (2D) in nature...
March 1, 2018: ACS Applied Materials & Interfaces
Valentina Meschini, Marco D de Tullio, Roberto Verzicco
In this paper a computational model for the ventricular flow with a mitral valve and modeled chordae tendineae is presented. The results are compared with an analogous case in which the chordae are not included and their presence is replaced by kinematic boundary conditions. The problem is studied using direct numerical simulation of the Navier-Stokes equations, two-way coupled with a structural solver for the ventricle and mitral valve dynamics. An experimental validation of the model is performed by a comparison of the results with a companion dedicated experiment...
February 28, 2018: European Physical Journal. E, Soft Matter
Cristina Montealegre, Christian Neusüß
Imaged capillary isoelectric focusing (iCIEF) is a powerful separation technique applied frequently for the analysis of biotherapeutics. However, direct mass spectrometric characterization is usually not possible. Here, focused peaks from an iCIEF system are transferred to a four-port nanoliter valve where peaks of interest are cut and transferred directly (flow injection) or via capillary zone electrophoresis to electrospray mass spectrometry. At first, flow injection coupling was tested with a mixture of peptides showing intraday precision (RSD) of 20...
February 22, 2018: Electrophoresis
Yen Ngoc Nguyen, Munirah Ismail, Foad Kabinejadian, Edgar Lik Wui Tay, Hwa Liang Leo
Intra-ventricular flow dynamics has recently emerged as an important evaluation and diagnosis tool in different cardiovascular conditions. The formation of vortex pattern during the cardiac cycle has been suggested to play important epigenetic and energy-modulation roles in cardiac remodelling, adaptations and mal-adaptations. In this new perspective, flow alterations due to different cardiovascular procedures can affect the long-term outcome of those procedures. Especially, repairs and replacements performed on atrioventricular valves are likely to exert direct impact on intra-ventricular flow pattern...
February 14, 2018: Medical Engineering & Physics
Emile S Farag, Pim van Ooij, R Nils Planken, Kayleigh C P Dukker, Frederiek de Heer, Berto J Bouma, Danielle Robbers-Visser, Maarten Groenink, Aart J Nederveen, Bas A J M de Mol, Jolanda Kluin, S Matthijs Boekholdt
BACKGROUND: Use of 4-dimensional flow magnetic resonance imaging (4D-flow MRI) derived wall shear stress (WSS) heat maps enables identification of regions in the ascending aorta with increased WSS. These regions are subject to dysregulation of the extracellular matrix and elastic fiber degeneration, which is associated with aortic dilatation and dissection. PURPOSE: To evaluate the effect of the presence of aortic valve stenosis and the aortic diameter on the peak WSS and surface area of increased WSS in the ascending aorta...
February 16, 2018: Journal of Magnetic Resonance Imaging: JMRI
Allison A Baczynski, Pratigya J Polissar, Dieter Juchelka, Johannes Schwieters, Andreas Hilkert, Roger E Summons, Katherine H Freeman
RATIONALE: We report modifications to compound-specific isotope analyses (CSIA) to enable high-precision isotopic analysis of picomoles of carbon for intact organic molecules. This sample size is two orders of magnitude below the amounts required for commercial systems. The greatly enhanced sensitivity of this system expands molecular isotope studies and applications previously prohibited by low concentrations and small samples. METHODS: We utilize the resolving power and low volumetric flow rates of narrow-bore capillary GC to improve sample transfer efficiency while maintaining narrow peak widths...
February 15, 2018: Rapid Communications in Mass Spectrometry: RCM
Wang Qing, Wu Yu Rong, Jiao Xian Ting, Wu Peng Fei, Zhao Li Qing, Chen Sun, Sun Kun
OBJECTIVES: To compare the fetal echocardiographic measurements and neonatal outcome of fetuses with diagnosis of critical pulmonary stenosis (CPS/IVS) and pulmonary atresia with intact ventricular septum (PA/IVS) in order to identify the predictors of neonatal ductus dependence and the need for neonatal intervention. METHODS: 44 fetuses with a diagnosis of membranous PA/IVS or CPS/IVS referred to Shanghai Xinhua Hospital Affiliated to Shanghai Jiaotong University between June 2009 and November 2014 were respectively analyzed...
February 7, 2018: Prenatal Diagnosis
Nicola Galea, Filippo Piatti, Francesco Sturla, Jonathan W Weinsaft, Christopher Lau, Ilaria Chirichilli, Iacopo Carbone, Emiliano Votta, Carlo Catalano, Ruggero De Paulis, Leonard N Girardi, Alberto Redaelli, Mario Gaudino
OBJECTIVES: This study was undertaken to evaluate the flow dynamics in the aortic root after valve-sparing root replacement with and without neosinuses of Valsalva reconstruction, by exploiting the capability of 4D Flow imaging to measure in vivo blood velocity fields and 3D geometric flow patterns. METHODS: Ten patients who underwent valve-sparing root replacement utilizing grafts with neosinuses or straight tube grafts (5 cases each) were evaluated by 4D Flow imaging at a mean of 46...
February 1, 2018: Interactive Cardiovascular and Thoracic Surgery
Dirk J Varelmann, Jochen Daniel Muehlschlegel
The year 2017 was a year dominated by large-scale clinical studies reporting the outcome of various interventions in cardiac surgery and heart failure (HF) patients, relevant to all cardiothoracic anesthesiologists. Among them were studies investigating the addition of levosimendan, an alternative inotropic agent, to standard management of patients with HF undergoing cardiac surgery. Also, corticosteroids have been used for various purposes in cardiac patients. Here, a new study reports the effect of high-dose methylprednisolone on recovery and delirium...
March 2018: Seminars in Cardiothoracic and Vascular Anesthesia
Marcos Tascon, Md Nazmul Alam, Germán Augusto Gómez-Ríos, Janusz Pawliszyn
Technologies that efficiently integrate the sampling and sample preparation steps with direct introduction to mass spectrometry (MS), providing simple and sensitive analytical workflows as well as capabilities for automation, can generate a great impact in a vast variety of fields, such as in clinical, environmental, and food-science applications. In this study, a novel approach that facilitates direct coupling of Bio-SPME devices to MS using a microfluidic design is presented. This technology, named microfluidic open interface (MOI), which operates under the concept of flow-isolated desorption volume, consists of an open-to-ambient desorption chamber (V ≤ 7 μL) connected to an ionization source...
February 1, 2018: Analytical Chemistry
Andrei Zholud, Ryan Freeman, Rongxing Cao, Ajit Srivastava, Sergei Urazhdin
We utilize a nanoscale magnetic spin-valve structure to demonstrate that current-induced magnetization fluctuations at cryogenic temperatures result predominantly from the quantum fluctuations enhanced by the spin transfer effect. The demonstrated spin transfer due to quantum magnetization fluctuations is distinguished from the previously established current-induced effects by a nonsmooth piecewise-linear dependence of the fluctuation intensity on current. It can be driven not only by the directional flows of spin-polarized electrons, but also by their thermal motion and by scattering of unpolarized electrons...
December 22, 2017: Physical Review Letters
Holly Payne, Alexander Brill
Deep vein thrombosis (DVT) and its devastating complication, pulmonary embolism, are a severe health problem with high mortality. Mechanisms of thrombus formation in veins remain obscure. Lack of mobility (e.g., after surgery or long-haul flights) is one of the main factors leading to DVT. The pathophysiological consequence of the lack of mobility is blood flow stagnation in venous valves. Here, a model is described that mimics such flow disturbance as a thrombosis-driving factor. In this model, partial flow restriction (stenosis) in the inferior vena cava (IVC) is created...
December 22, 2017: Journal of Visualized Experiments: JoVE
Antonino S Rubino, Carmelo Mignosa
BACKGROUND: Aim of this study was to assess the potential differences in respecting the principles of goal-directed perfusion between aortic valve replacement with sutureless vs conventional stented bioprostheses. METHODS: Data from 94 consecutive patients undergoing aortic valve replacement with Perceval sutureless valve, with or without concomitant CABG, were compared to a contemporary cohort of 116 patients receiving conventional stented bioprostheses. Propensity score matching was used to reduce selection bias...
December 14, 2017: Minerva Cardioangiologica
Vaibhav Varade, Tal Markus, Kiran Vankayala, Noga Friedman, Mordechai Sheves, David H Waldeck, Ron Naaman
We discuss spin injection and spin valves, which are based on organic and biomolecules, that offer the possibility to overcome some of the limitations of solid-state devices, which are based on ferromagnetic metal electrodes. In particular, we discuss spin filtering through bacteriorhodopsin in a solid state biomolecular spin valve that is based on the chirality induced spin selectivity (CISS) effect and shows a magnetoresistance of ∼2% at room temperature. The device is fabricated using a layer of bacteriorhodopsin (treated with n-octyl-thioglucoside detergent: OTG-bR) that is adsorbed on a cysteamine functionalized gold electrode and capped with a magnesium oxide layer as a tunneling barrier, upon which a Ni top electrode film is placed and used as a spin analyzer...
December 13, 2017: Physical Chemistry Chemical Physics: PCCP
Mansi Shah, Michael R Phillips, Megan Quintana, Gary Stupp, Sean E McLean
BACKGROUND: Congenital diaphragmatic hernia (CDH) is a structural birth defect associated with pulmonary hypoplasia and pulmonary arterial hypertension (PAH). We hypothesize that echocardiography provides a method to assess real-time right ventricle (RV) function, remodeling, and pulmonary artery (PA) flow. MATERIALS AND METHODS: Slit3 wild-type (WT) (n = 6) and knockout (KO) (n = 5) mice were analyzed at 2-3 months of age. Mice were anesthetized using isoflurane...
January 2018: Journal of Surgical Research
Julia Geiger, Amir A Rahsepar, Kenichiro Suwa, Alex Powell, Ahmadreza Ghasemiesfe, Alex J Barker, Jeremy D Collins, James C Carr, Michael Markl
BACKGROUND: Patients with bicuspid aortic valve (BAV) show altered hemodynamics in the ascending aorta that can be assessed by 4D flow MRI. PURPOSE: Comprehensive cardiac MRI was applied to test the hypothesis that BAV-mediated changes in aortic hemodynamics (wall shear stress [WSS] and velocity) are associated with parameters of left ventricular (LV) remodeling. STUDY TYPE: Retrospective data analysis. POPULATION: Forty-nine BAV patients (mean age = 50...
December 5, 2017: Journal of Magnetic Resonance Imaging: JMRI
Francesco Boselli, Emily Steed, Jonathan B Freund, Julien Vermot
Myocardial contractility and blood flow provide essential mechanical cues for the morphogenesis of the heart. In general, endothelial cells change their migratory behavior in response to shear stress patterns, according to flow directionality. Here, we assessed the impact of shear stress patterns and flow directionality on the behavior of endocardial cells, the specialized endothelial cells of the heart. At the early stages of zebrafish heart valve formation, we show that endocardial cells are converging to the valve-forming area and that this behavior depends upon mechanical forces...
December 1, 2017: Development
Karin Lavon, Rotem Halevi, Gil Marom, Sagit Ben Zekry, Ashraf Hamdan, Hans Joachim Schäfers, Ehud Raanani, Rami Haj-Ali
Bicuspid aortic valve (BAV) is the most common type of congenital heart disease, occurring in 0.5-2% of the population, where the valve has only two rather than the three normal cusps. Valvular pathologies, such as aortic regurgitation and aortic stenosis, are associated with BAVs, thereby increasing the need for a better understanding of BAV kinematics and geometrical characteristics. The aim of this study is to investigate the influence of the non-fused cusp (NFC) angle in BAV type-1 configuration on the valve's structural and hemodynamic performance...
November 2, 2017: Journal of Biomechanical Engineering
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