University of Bonn

About: University of Bonn is a education organization based out in Bonn, Germany. It is known for research contribution in the topics: Population & Galaxy. The organization has 43200 authors who have published 86473 publications receiving 3106223 citations. The organization is also known as: Rheinische Friedrich-Wilhelms-Universität Bonn & Universität Bonn.

Antigen-presenting cells in allergy.

Abstract: The complex interaction of the innate and adaptive immune system requires flexibility and cooperation among various cell types. In this regard, antigen-presenting-cells (APCs) play a pivotal role in transferring information from the periphery of the organism to lymphoid organs, where they initiate the activation of naive T cells. Dendritic cells, Langerhans' cells (LCs), and macrophages are also critical in the induction of allergic inflammation by presenting allergens to T lymphocytes and by contributing to the local recruitment of effector cells. Because of a complex genetic background, atopic individuals exhibit a dysregulation of T cell-mediated immune mechanisms. Attempts to understand the role APCs play in these pathophysiologic conditions are in progress and may allow development of new treatment strategies. In this review we will focus on the biology of APCs and their unique role in the induction and control of allergic inflammation.

Polynomial bounds for VC dimension of sigmoidal neural networks

Abstract: We introduce a new method for proving explicit upper bounds on the VC Dimension of general functional basis networks, and prove as an application, for the first time, the VC Dimension of analog neural networks with the sigmoid activation function o(y) = 1/1 + e-y to be bounded by a quadratic polynomial in the number of programmable parameters.

Low-Molecular Weight Proteins as Markers for Glomerular Filtration Rate

Abstract: Inulin clearance (CIn) is the usual gold standard for evaluating glomerular filtration rate (GFR), but technical difficulties and patient inconvenience prevent its widespread use (1). The most commonly used marker for GFR is serum creatinine, but muscle wasting and tubular secretion may lead to overestimation of GFR (2)(3). Serum concentrations of the low-molecular weight proteins cystatin C (CysC) (4), β2-microglobulin (B2M) (5)(6), and β-trace protein (BTP) (7) maybe useful alternatives for detecting reduced GFR, but no study to date has compared all of these proteins directly to CIn. We studied 62 patients (20 females, 42 males). All had their GFR determined by steady-state CIn as described previously and adjusted to a standard body surface of 1.73 m2. We had reported on CysC and creatinine in 44 patients with various degrees of liver cirrhosis (1). We include here 41 of these patients for whom samples were available and 3 new patients with liver diseases; 31 had alcoholic etiologies; 10 had viral hepatitis, and 3 had other etiologies. The remaining 18 patients had renal diseases: 5 with chronic renal failure, 2 with acute renal failure, and 11 others. After an overnight fast, GFR was tested with participants in a supine position. Serum creatinine was determined by a Jaffe method (1). Serum CysC, B2M, and BTP were analyzed by fully automated, …

Cross-presentation of antigens from apoptotic tumor cells by liver sinusoidal endothelial cells leads to tumor-specific CD8+ T cell tolerance.

Abstract: Development of tumor-specific T cell tolerance contributes to the failure of the immune system to eliminate tumor cells. Here we report that hematogenous dissemination of tumor cells followed by their elimination and local removal of apoptotic tumor cells in the liver leads to subsequent development of T cell tolerance towards antigens associated with apoptotic tumor cells. We provide evidence that liver sinusoidal endothelial cells (LSEC) remove apoptotic cell fragments generated by induction of tumor cell apoptosis through hepatic NK1.1+ cells. Antigen associated with apoptotic cell material is processed and cross-presented by LSEC to CD8+ T cells, leading to induction of CD8+ T cell tolerance. Adoptive transfer of LSEC isolated from mice challenged previously with tumor cells promotes development of CD8+ T cell tolerance towards tumor-associated antigen in vivo. Our results indicate that hematogenous dissemination of tumor cells, followed by hepatic tumor cell elimination and local cross-presentation of apoptotic tumor cells by LSEC and subsequent CD8+ T cell tolerance induction, represents a novel mechanism operative in tumor immune escape.

Measurement of the photon identification efficiencies with the ATLAS detector using LHC Run-1 data

Abstract: The algorithms used by the ATLAS Collaboration to reconstruct and identify prompt photons are described. Measurements of the photon identification efficiencies are reported, using 4.9 fb$^{-1}$ of $pp$ collision data collected at the LHC at $\sqrt{s} = 7$ TeV and 20.3 fb$^{-1}$ at $\sqrt{s} = 8$ TeV. The efficiencies are measured separately for converted and unconverted photons, in four different pseudo rapidity regions, for transverse momenta between 10 GeV and 1.5 TeV. The results from the combination of three data-driven techniques are compared to the predictions from a simulation of the detector response, after correcting the electromagnetic shower momenta in the simulation for the average differences observed with respect to data. Data-to-simulation efficiency ratios used as correction factors in physics measurements are determined to account for the small residual efficiency differences. These factors are measured with uncertainties between 0.5% and 10% in 7 TeV data and between 0.5% and 3% in 8 TeV data, depending on the photon transverse momentum and pseudorapidity.