On the Identification of Symmetric Quadrature Rules for Finite Element Methods

In this paper we describe a methodology for the identification of symmetric quadrature rules inside of quadrilaterals, triangles, tetrahedra, prisms, pyramids, and hexahedra. The methodology is free from manual intervention and is capable of identifying an ensemble of rules with a given strength and a given number of points. We also present polyquad which is an implementation of our methodology. Using polyquad we proceed to derive a complete set of symmetric rules on the aforementioned domains. All rules possess purely positive weights and have all points inside the domain. Many of the rules appear to be new, and an improvement over those tabulated in the literature.Comment: 17 pages, 6 figures, 1 tabl

Heterogeneous Computing on Mixed Unstructured Grids with PyFR

PyFR is an open-source high-order accurate computational fluid dynamics solver for mixed unstructured grids that can target a range of hardware platforms from a single codebase. In this paper we demonstrate the ability of PyFR to perform high-order accurate unsteady simulations of flow on mixed unstructured grids using heterogeneous multi-node hardware. Specifically, after benchmarking single-node performance for various platforms, PyFR v0.2.2 is used to undertake simulations of unsteady flow over a circular cylinder at Reynolds number 3 900 using a mixed unstructured grid of prismatic and tetrahedral elements on a desktop workstation containing an Intel Xeon E5-2697 v2 CPU, an NVIDIA Tesla K40c GPU, and an AMD FirePro W9100 GPU. Both the performance and accuracy of PyFR are assessed. PyFR v0.2.2 is freely available under a 3-Clause New Style BSD license (see www.pyfr.org).Comment: 21 pages, 9 figures, 6 table

Reduction of nitric oxide release from alveolar macrophages by a lipocortin peptide.

Nitric oxide (NO), produced by alveolar macrophages (AM) is used as a marker of respiratory tract inflammation. Lipocortin 1 (Lc-1) is an anti-inflammatory, glucocorticoid-inducible protein. The current aims were to determine whether (a) an Lc-1-derived peptide, Ac2-26, inhibited lipopolysaccharide (LPS)-induced NO release by primary AM in vitro and (b) the inhibitory action of dexamethasone was Lc-1-dependent. LPS treatment stimulated NO release from rat AM. Ac2-26 had little effect on unstimulated release, but suppressed LPS-stimulated release at concentrations > or =320 nM (320 nM, 10 +/- 3%; 3.2 microM, 15 +/- 3%; 32 microM, 27 +/- 4% NO inhibited, mean +/- SEM, n = 6). Inhibition by dexamethasone of NO release was unaffected by neutralizing anti-Lc-1 indicating that this action is Lc-1-independent in primary AM. Nevertheless inhibition of NO release by Ac2-26 (80 microM) was similar to that of 1 microM dexamethasone (Ac2-26, 40 +/- 6%; dexamethasone, 48 +/- 6% NO inhibited, mean +/- SEM, n = 6)

cDNA Sequence and Fab Crystal Structure of HL4E10, a Hamster IgG Lambda Light Chain Antibody Stimulatory for γδ T Cells

Hamsters are widely used to generate monoclonal antibodies against mouse, rat, and human antigens, but sequence and structural information for hamster immunoglobulins is sparse. To our knowledge, only three hamster IgG sequences have been published, all of which use kappa light chains, and no three-dimensional structure of a hamster antibody has been reported. We generated antibody HL4E10 as a probe to identify novel costimulatory molecules on the surface of γδ T cells which lack the traditional αβ T cell co-receptors CD4, CD8, and the costimulatory molecule CD28. HL4E10 binding to γδ T cell, surface-expressed, Junctional Adhesion Molecule-Like (JAML) protein leads to potent costimulation via activation of MAP kinase pathways and cytokine production, resulting in cell proliferation. The cDNA sequence of HL4E10 is the first example of a hamster lambda light chain and only the second known complete hamster heavy chain sequence. The crystal structure of the HL4E10 Fab at 2.95 Å resolution reveals a rigid combining site with pockets faceted by solvent-exposed tyrosine residues, which are structurally optimized for JAML binding. The characterization of HL4E10 thus comprises a valuable addition to the spartan database of hamster immunoglobulin genes and structures. As the HL4E10 antibody is uniquely costimulatory for γδ T cells, humanized versions thereof may be of clinical relevance in treating γδ T cell dysfunction-associated diseases, such as chronic non-healing wounds and cancer

A unified approach for a posteriori high-order curved mesh generation using solid mechanics

The paper presents a unified approach for the a posteriori generation of arbitrary high-order curvilinear meshes via a solid mechanics analogy. The approach encompasses a variety of methodologies, ranging from the popular incremental linear elastic approach to very sophisticated non-linear elasticity. In addition, an intermediate consistent incrementally linearised approach is also presented and applied for the first time in this context. Utilising a consistent derivation from energy principles, a theoretical comparison of the various approaches is presented which enables a detailed discussion regarding the material characterisation (calibration) employed for the different solid mechanics formulations. Five independent quality measures are proposed and their relations with existing quality indicators, used in the context of a posteriori mesh generation, are discussed. Finally, a comprehensive range of numerical examples, both in two and three dimensions, including challenging geometries of interest to the solids, fluids and electromagnetics communities, are shown in order to illustrate and thoroughly compare the performance of the different methodologies. This comparison considers the influence of material parameters and number of load increments on the quality of the generated high-order mesh, overall computational cost and, crucially, the approximation properties of the resulting mesh when considering an isoparametric finite element formulation

Impact of the TCR Signal on Regulatory T Cell Homeostasis, Function, and Trafficking

Signaling through the T cell antigen receptor (TCR) is important for the homeostasis of naïve and memory CD4+ T cells. The significance of TCR signaling in regulatory T (Treg) cells has not been systematically addressed. Using an Ox40-cre allele that is prominently expressed in Treg cells, and a conditional null allele of the gene encoding p56Lck, we have examined the importance of TCR signaling in Treg cells. Inactivation of p56Lck resulted in abnormal Treg homeostasis characterized by impaired turnover, preferential redistribution to the lymph nodes, loss of suppressive function, and striking changes in gene expression. Abnormal Treg cell homeostasis and function did not reflect the involvement of p56Lck in CD4 function because these effects were not observed when CD4 expression was inactivated by Ox40-cre.The results make clear multiple aspects of Treg cell homeostasis and phenotype that are dependent on a sustained capacity to signal through the TCR