981 research outputs found

    Oil cooling system for a gas turbine engine

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    A gas turbine engine fuel delivery and control system is provided with means to recirculate all fuel in excess fuel control requirements back to the aircraft fuel tank. This increases the fuel pump heat sink and decreases the pump temperature rise without the addition of valving other than normally employed. A fuel/oil heat exchanger and associated circuitry is provided to maintain the hot engine oil in heat exchange relationship with the cool engine fuel. Where anti-icing of the fuel filter is required, means are provided to maintain the fuel temperature entering the filter at or above a minimum level to prevent freezing thereof. In one embodiment, a divider valve is provided to take all excess fuel from either upstream or downstream of the fuel filter and route it back to the tanks, the ratio of upstream to downstream extraction being a function of fuel pump discharge pressure

    ECHO user's guide

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    There are no author-identified significant results in this report

    Computer processing support, volume 4

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    There are no author-identified significant results in this report

    Kupferersatz im ökologischen Weinbau: Entwicklung und Anwendung neuer Formulierungs- und Produktionstechnologien fĂŒr den praxisgerechten Einsatz bakterieller Antagonisten

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    Im vorliegenden Projekt wurde der Einsatz bakterieller Antagonisten als Kupferersatz zur BekĂ€mpfung von Plasmopara viticola, dem Erreger des Falschen Mehltaus der Weinrebe, im ökologischen Weinbau optimiert. Mit Hilfe von Dual-Kultur-Tests wurden sechs bakterielle Antagonisten aus vorhandenen Antagonisten-Stammsammlungen selektiert (Testpilze: Pythium ultimum; Phytophthora infestans). Mittels Blattscheiben-Test im Labor konnte mit den ausgewĂ€hlten Isolaten eine Befallsreduzierung auf unter 5 % BefallsstĂ€rke erzielt werden. Der Befall in der unbehandelten Kontrolle schwankte je nach Ansatz zwischen 19 % und 35 %. Unter GewĂ€chshausbedingungen zeigte sich an Topfreben ebenfalls eine gute biologische Wirksamkeit gegen den Schadpilz. Die Kontrollpflanzen wiesen einen Befall zwischen 60 % und 77 % BefallsstĂ€rke auf, wĂ€hrend die BlĂ€tter der PrĂŒfglieder weniger als 5 % BefallsstĂ€rke zeigten. Zur Eliminierung des Kupferanteils wurden fĂŒr die Freilandversuche drei hochwirksame Isolate ausgewĂ€hlt und in die BekĂ€mpfungsstrategie „Öko-Standard“ integriert. Die Isolate gehörten den Bakteriengattungen Pseudomonas spp. und Bacillus spp. an. Um die Wirksamkeit im Freiland zu steigern, wurden Formulierungshilfsstoffe ausgewĂ€hlt, die den Bakterien kurz vor der Applikation zugesetzt wurden. Dabei fanden die Substanzen Xanthan gum, Trehalose und PHYTO-VITALÂź Anwendung. Aufgrund des extremen Sommers im Jahr 2003 war der Peronospora-Befall im Weinberg so gering, dass keine aussagekrĂ€ftigen Ergebnisse zum Einsatz unter Freilandbedingungen gemacht werden konnten. Studien zur Etablierung der Antagonisten auf dem Rebblatt haben gezeigt, dass die BlĂ€tter der bakterienbehandelten Versuchsglieder Bakteriendichten aufwiesen, die um etwa eine Zehnerpotenz höher lagen als die mit Kupfer behandelten BlĂ€tter. Um mögliche GĂ€rbeeinflussungen zu erfassen, wurden die Moste im Kleinmaßstab (25-Liter GĂ€rbehĂ€lter) vergoren. Bisher zeigten sich keine Abweichungen vom kupferhaltigen Versuchsglied „Öko-Standard“

    ECHO User\u27s Guide

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    Over the past several years, the ECHO classifiers have been developed to incorporate spatial as well as spectral information into the classifier decision criteria. This document contains a comprehensive description of the functional organization of the supervised and the nonsupervised ECHO processes, the manner in for individuals who intend to make use of the ECHO classifiers, although it is also of value to those wanting to understand of implement the ECHO algorithms

    FLT3-regulated antigens as targets for leukemia-reactive cytotoxic T lymphocytes

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    The FMS-like tyrosine kinase 3 (FLT3) is highly expressed in acute myeloid leukemia (AML). Internal tandem duplications (ITD) of the juxtamembrane domain lead to the constitutive activation of the FLT3 kinase inducing the activation of multiple genes, which may result in the expression of leukemia-associated antigens (LAAs). We analyzed the regulation of LAA in FLT3-wild-type (WT)- and FLT3-ITD+ myeloid cells to identify potential targets for antigen-specific immunotherapy for AML patients. Antigens, such as PR-3, RHAMM, Survivin, WT-1 and PRAME, were upregulated by constitutively active FLT3-ITD as well as FLT3-WT activated by FLT3 ligand (FL). Cytotoxic T-cell (CTL) clones against PR-3, RHAMM, Survivin and an AML-directed CTL clone recognized AML cell lines and primary AML blasts expressing FLT3-ITD, as well as FLT3-WT+ myeloid dendritic cells in the presence of FL. Downregulation of FLT3 led to the abolishment of CTL recognition. Comparing our findings concerning LAA upregulation by the FLT3 kinase with those already made for the Bcr-Abl kinase, we found analogies in the LAA expression pattern. Antigens upregulated by both FLT3 and Bcr-Abl may be promising targets for the development of immunotherapeutical approaches against myeloid leukemia of different origin

    A Joint Venture of Ab Initio Molecular Dynamics, Coupled Cluster Electronic Structure Methods, and Liquid-State Theory to Compute Accurate Isotropic Hyperfine Constants of Nitroxide Probes in Water

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    The isotropic hyperfine coupling constant (HFCC, Aiso) of a pH-sensitive spin probe in a solution, HMI (2,2,3,4,5,5-hexamethylimidazolidin-1-oxyl, C9H19N2O) in water, is computed using an ensemble of state-of-the-art computational techniques and is gauged against X-band continuous wave electron paramagnetic resonance (EPR) measurement spectra at room temperature. Fundamentally, the investigation aims to delineate the cutting edge of current first-principles-based calculations of EPR parameters in aqueous solutions based on using rigorous statistical mechanics combined with correlated electronic structure techniques. In particular, the impact of solvation is described by exploiting fully atomistic, RISM integral equation, and implicit solvation approaches as offered by ab initio molecular dynamics (AIMD) of the periodic bulk solution (using the spin-polarized revPBE0-D3 hybrid functional), embedded cluster reference interaction site model integral equation theory (EC-RISM), and polarizable continuum embedding (using CPCM) of microsolvated complexes, respectively. HFCCs are obtained from efficient coupled cluster calculations (using open-shell DLPNO-CCSD theory) as well as from hybrid density functional theory (using revPBE0-D3). Re-solvation of “vertically desolvated” spin probe configuration snapshots by EC-RISM embedding is shown to provide significantly improved results compared to CPCM since only the former captures the inherent structural heterogeneity of the solvent close to the spin probe. The average values of the Aiso parameter obtained based on configurational statistics using explicit water within AIMD and from EC-RISM solvation are found to be satisfactorily close. Using either such explicit or RISM solvation in conjunction with DLPNO-CCSD calculations of the HFCCs provides an average Aiso parameter for HMI in aqueous solution at 300 K and 1 bar that is in good agreement with the experimentally determined one. The developed computational strategy is general in the sense that it can be readily applied to other spin probes of similar molecular complexity, to aqueous solutions beyond ambient conditions, as well as to other solvents in the longer run

    Shot-noise spectroscopy of energy-resolved ballistic currents

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    We investigate the shot noise of nonequilibrium carriers injected into a ballistic conductor and interacting via long-range Coulomb forces. Coulomb interactions are shown to act as an energy analyzer of the profile of injected electrons by means of the fluctuations of the potential barrier at the emitter contact. We show that the details in the energy profile can be extracted from shot-noise measurements in the Coulomb interaction regime, but cannot be obtained from time-averaged quantities or shot-noise measurements in the absence of interactions.Comment: 7 pages, 4 figure

    Estimating the Predictive Value of Negative SARS-CoV-2 Results: A Prospective Study

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    © 2020 by The Society for Healthcare Epidemiology of America. All rights reserved. We performed a prospective study of 501 patients, regardless of symptoms, admitted to the hospital, to estimate the predictive value of a negative Nasopharyngeal swab for SARS-CoV-2. At a positivity rate of 10.2%, the estimated Negative Predictive Value (NPV) was 97.2% and NPV rose as prevalence decreased during the study
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