200 research outputs found

    Computational analysis of single rising bubbles influenced by soluble surfactant

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    This paper presents novel insights about the influence of soluble surfactants on bubble flows obtained by Direct Numerical Simulation (DNS). Surfactants are amphiphilic compounds which accumulate at fluid interfaces and significantly modify the respective interfacial properties, influencing also the overall dynamics of the flow. With the aid of DNS local quantities like the surfactant distribution on the bubble surface can be accessed for a better understanding of the physical phenomena occurring close to the interface. The core part of the physical model consists in the description of the surfactant transport in the bulk and on the deformable interface. The solution procedure is based on an Arbitrary Lagrangian-Eulerian (ALE) Interface-Tracking method. The existing methodology was enhanced to describe a wider range of physical phenomena. A subgrid-scale (SGS) model is employed in the cases where a fully resolved DNS for the species transport is not feasible due to high mesh resolution requirements and, therefore, high computational costs. After an exhaustive validation of the latest numerical developments, the DNS of single rising bubbles in contaminated solutions is compared to experimental results. The full velocity transients of the rising bubbles, especially the contaminated ones, are correctly reproduced by the DNS. The simulation results are then studied to gain a better understanding of the local bubble dynamics under the effect of soluble surfactant. One of the main insights is that the quasi-steady state of the rise velocity is reached without ad- and desorption being necessarily in local equilibrium

    Induction of Immunological Tolerance by Oral Anti-CD3

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    In recent years, our knowledge about immunoregulation and autoimmunity has significantly advanced, but nontoxic and more effective treatments for different inflammatory and autoimmune diseases are still lacking. Oral tolerance is of unique immunologic importance because it is a continuous natural immunologic event driven by exogenous antigen and is an attractive approach for treatment of these conditions. Parenteral administration of anti-CD3 monoclonal antibody is an approved therapy for transplantation in humans and is effective in autoimmune diabetes. Orally administered anti-CD3 monoclonal antibody is biologically active in the gut and suppresses experimental models of autoimmune diseases. Orally delivered antibody does not have side effects including cytokine release syndromes, thus oral anti-CD3 antibody is clinically applicable for chronic therapy. Here we review findings that identify a novel and powerful immunologic approach that is widely applicable for the treatment of human autoimmune conditions

    xROM: A Toolkit for Reduced-Order Modeling of Fluid Flows

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    This book initiates the new Series `Machine Learning Tools in Fluid Mechanics' published by the Technische Universität Braunschweig. The series focuses on machine learning tools for fluid mechanics tasks, like analysis, dynamic modeling, response modeling, control and closures. The tools comprise documentations of publicly available software packages, of good practices and of application studies. Our book introduces the software platform xROM, which is a freely available package for spectral analysis and reduced-order modeling. Initially, xROM was developed as a tool to quickly derive dynamic POD models from snapshot data and Galerkin projection using the Navier-Stokes equations. This purpose has since expanded, and xROM has become a platform that allows easy modular expansions and collaborations with partners worldwide. In this book, however, we focus on POD-based Galerkin modeling for reasons of simplicity

    Towards physics-based deep learning in OpenFOAM: Combining OpenFOAM with the PyTorch C++ API (Slides)

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    Slides from the Training "Towards physics-based deep learning in OpenFOAM: Combining OpenFOAM with the PyTorch C++ API" given at the 17th OpenFOAM Workshop1.

    Beliefs around luck : confirming the empirical conceptualization of beliefs around luck and the development of the Darke and Freedman beliefs around luck scale

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    The current study developed a multi-dimensional measure of beliefs around luck. Two studies introduced the Darke and Freedman beliefs around luck scale where the scale showed a consistent 4 component model (beliefs in luck, rejection of luck, being lucky, and being unlucky) across two samples (n = 250; n = 145). The scales also show adequate reliability statistics and validity by ways of comparison with other measures of beliefs around luck, peer and family ratings and expected associations with measures of personality, individual difference and well-being variables

    In Vivo Induction of Tr1 Cells via Mucosal Dendritic Cells and AHR Signaling

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    Background: Type 1 regulatory T (Tr1) cells, characterized by the secretion of high levels of the anti-inflammatory cytokine interleukin-10 (IL-10), play an important role in the regulation of autoimmune diseases and transplantation. However, effective strategies that specifically induce Tr1 cells in vivo are limited. Furthermore, the pathways controlling the induction of these cells in vivo are not well understood. Methodology/Principal Findings: Here we report that nasal administration of anti-CD3 antibody induces suppressive Tr1 cells in mice. The in vivo induction of Tr1 cells by nasal anti-CD3 is dependent on IL-27 produced by upper airway resident dendritic cells (DCs), and is controlled by the transcription factors aryl hydrocarbon receptor (AHR) and c-Maf. Subsequently, IL-21 acts in an autocrine fashion to expand and maintain the Tr1 cells induced in vivo by nasally administered anti-CD3. Conclusions/Significance: Our findings identify a unique approach to generate Tr1 cells in vivo and provide insights into the mechanisms by which these cells are induced

    The Cosmic Ultraviolet Baryon Survey (CUBS) I. Overview and the diverse environments of Lyman limit systems at z<1

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    We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z<~1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman Limit Systems (LLSs) at zabs~ 17.2 over a total redshift survey pathlength of dz=9.3, and a number density of n(z)=0.43 (-0.18, +0.26). Considering all absorbers with log N(HI)/cm^-2 > 16.5 leads to n(z)=1.08 (-0.25, +0.31) at z<1. All LLSs exhibit a multi-component structure and associated metal transitions from multiple ionization states such as CII, CIII, MgII, SiII, SiIII, and OVI absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than 0.1L* at d<~300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disk, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d=15 to 72 pkpc and intrinsic luminosities from ~0.01L* to ~3L*. Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities.Comment: 26 pages, 14 figures, MNRAS in pres

    Efficiently combining Machine Learning with OpenFOAM using SmartSim - Slides

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    Slides: 18th OpenFOAM Workshop - Efficiently combining Machine Learning with OpenFOAM using SmartSim1.

    International criteria for electrocardiographic interpretation in athletes: Consensus statement.

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    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD

    IL-27 Imparts Immunoregulatory Function to Human NK Cell Subsets

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    Interleukin-27 (IL-27) is a cytokine with multiple roles in regulating the immune response, but its effect on human CD56bright and CD56dim NK cell subsets is unknown. NK cell subsets interact with other components of the immune system, leading to cytotoxicity or immunoregulation depending on stimulating factors. We found that IL-27 treatment results in increased IL-10 and IFN-γ expression, increased viability and decreased proliferation in both CD56bright and CD56dim NK cell subsets. More importantly, IL-27 treatment imparts regulatory activity to CD56bright NK cells, which mediates its suppressive function on T cells in a contact-dependent manner. There is growing evidence that CD56bright NK cell-mediated immunoregulation plays an important role in the control of autoimmunity. Thus, understanding the role of IL-27 in NK cell function has important implications for treatment of autoimmune disorders
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