4,001 research outputs found

    Takayasu's arteritis in children : a review

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    Takayasu's arteritis is an inflammatory disease of unknown origin involving aorta, its primary branches and pulmonary artery. This article briefly reviews the pathology, clinical features and treatment of Takayasu's arteritis, focusing mainly on the disease in children.peer-reviewe

    The caveats in the diagnosis of anomalous origin of left coronary artery from pulmonary artery (ALCAPA)

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    Anomalous origin of left coronary artery from pulmonary artery (ALCAPA) is an infrequent, well described, but important anomaly of the coronary origin. Early diagnosis and prompt surgical treatment of the disease can be life saving. However, there are several potential sources of error in the seemingly simple stereotype diagnostic pattern. This article reports a case of ALCAPA and allude to some of the caveats in the diagnosis of this entity.peer-reviewe

    Driven weak to strong pinning crossover in partially nanopatterned 2H-NbSe2 single crystal

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    Investigations into the heterogeneous pinning properties of the vortex state created by partially nano-patterning single crystals of 2H-NbSe2 reveal an atypical magnetization response which is significantly drive dependent. Analysis of the magnetization response shows non-monotonic behavior of the magnetization relaxation rate with varying magnetic field sweep rate. With all the patterned pinning centers saturated with vortices, we find that the pinning force experienced by the vortices continues to increase with increasing drive. Our studies reveal an unconventional dynamic weak to strong pinning crossover where the flow of the vortex state appears to be hindered or jammed as it is driven harder through the interstitial voids in the patterned pinning lattice.Comment: 15 pages with 5 figure

    Entropic Multi-Relaxation Models for Simulation of Fluid Turbulence

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    A recently introduced family of lattice Boltzmann (LB) models (Karlin, B\"osch, Chikatamarla, Phys. Rev. E, 2014) is studied in detail for incompressible two-dimensional flows. A framework for developing LB models based on entropy considerations is laid out extensively. Second order rate of convergence is numerically confirmed and it is demonstrated that these entropy based models recover the Navier-Stokes solution in the hydrodynamic limit. Comparison with the standard Bhatnagar-Gross-Krook (LBGK) and the entropic lattice Boltzmann method (ELBM) demonstrates the superior stability and accuracy for several benchmark flows and a range of grid resolutions and Reynolds numbers. High Reynolds number regimes are investigated through the simulation of two-dimensional turbulence, particularly for under-resolved cases. Compared to resolved LBGK simulations, the presented class of LB models demonstrate excellent performance and capture the turbulence statistics with good accuracy.Comment: To be published in Proceedings of Discrete Simulation of Fluid Dynamics DSFD 201

    Classical supravalvar aortic stenosis and peripheral pulmonary stenosis

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    Supravalvar aortic stenosis as well as peripheral pulmonary stenosis are rare forms of congenital heart disease, which occur, however, relatively frequently in association. This article reports and discusses the classical findings of SVAS and PPS upon clinical examination and imaging in a sixyear-old girl that presented with repeated respiratory tract infections and failure to thrive.peer-reviewe

    Drops bouncing off macro-textured superhydrophobic surfaces

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    Recent experiments with droplets impacting a macro-textured superhydrophobic surfaces revealed new regimes of bouncing with a remarkable reduction of the contact time. We present here a comprehensive numerical study that reveals the physics behind these new bouncing regimes and quantify the role played by various external and internal forces that effect the dynamics of a drop impacting a complex surface. For the first time, three-dimensional simulations involving macro-textured surfaces are performed. Aside from demonstrating that simulations reproduce experiments in a quantitative manner, the study is focused on analyzing the flow situations beyond current experiments. We show that the experimentally observed reduction of contact time extends to higher Weber numbers, and analyze the role played by the texture density. Moreover, we report a non-linear behavior of the contact time with the increase of the Weber number for application relevant imperfectly coated textures, and also study the impact on tilted surfaces in a wide range of Weber numbers. Finally, we present novel energy analysis techniques that elaborate and quantify the interplay between the kinetic and surface energy, and the role played by the dissipation for various Weber numbers

    Fluid-Structure Interaction with the Entropic Lattice Boltzmann Method

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    We propose a novel fluid-structure interaction (FSI) scheme using the entropic multi-relaxation time lattice Boltzmann (KBC) model for the fluid domain in combination with a nonlinear finite element solver for the structural part. We show validity of the proposed scheme for various challenging set-ups by comparison to literature data. Beyond validation, we extend the KBC model to multiphase flows and couple it with FEM solver. Robustness and viability of the entropic multi-relaxation time model for complex FSI applications is shown by simulations of droplet impact on elastic superhydrophobic surfaces
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