2,215 research outputs found

    Contrast-Enhanced Magnetic Resonance Angiography Using a Novel Elastin-Specific Molecular Probe in an Experimental Animal Model

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    Objectives. The aim of this study was to test the potential of a new elastin-specific molecular agent for the performance of contrast-enhanced first-pass and 3D magnetic resonance angiography (MRA), compared to a clinically used extravascular contrast agent (gadobutrol) and based on clinical MR sequences. Materials and Methods. Eight C57BL/6J mice (BL6, male, aged 10 weeks) underwent a contrast-enhanced first-pass and 3D MR angiography (MRA) of the aorta and its main branches. All examinations were on a clinical 3 Tesla MR system (Siemens Healthcare, Erlangen, Germany). The clinical dose of 0.1 mmol/kg was administered in both probes. First, a time-resolved MRA (TWIST) was acquired during the first-pass to assess the arrival and washout of the contrast agent bolus. Subsequently, a high-resolution 3D MRA sequence (3D T1 FLASH) was acquired. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for all sequences. Results. The elastin-specific MR probe and the extravascular imaging agent (gadobutrol) enable high-quality MR angiograms in all animals. During the first-pass, the probes demonstrated a comparable peak enhancement (300.6 +/- 32.9 vs. 288.5 +/- 33.1, p > 0.05). Following the bolus phase, both agents showed a comparable intravascular enhancement (SNR: 106.7 +/- 11 vs. 102.3 +/- 5.3; CNR 64.5 +/- 7.4 vs. 61.1 +/- 7.2, p > 0.05). Both agents resulted in a high image quality with no statistical difference (p > 0.05). Conclusion. The novel elastin-specific molecular probe enables the performance of first-pass and late 3D MR angiography with an intravascular contrast enhancement and image quality comparable to a clinically used extravascular contrast agent

    Technologien fĂĽr die Energiewende - Kriterienraster: Teilbericht 1 zum Teilprojekt A im Rahmen des strategischen BMWi-Leitprojekts "Trends und Perspektiven der Energieforschung"

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    Der Teilbericht 1 stellt die Methodik dar, die im Forschungsvorhaben "Technologien fĂĽr die Energiewende" zur multikriteriellen Bewertung von 31 Technologiefeldern verwendet wurde

    Technologien fĂĽr die Energiewende - Politikbericht: Teilprojekt A im Rahmen des strategischen BMWi-Leitprojekts "Trends und Perspektiven der Energieforschung"

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    Der Politikbericht ist ein Ergebnis des Forschungsvorhabens "Technologien für die Energiewende", das vom Bundesministerium für Wirtschaft und Energie (BMWi) als Teil des strategischen Leitprojekts "Trends und Perspektiven der Energieforschung" von 2016 bis 2018 gefördert wurde. Er enthält neben einer kurzen deutschen und englischen Einleitung vierseitige Zusammenfassungen zu jedem der 31 analysierten Technologiefelder und eine Kurzdarstellung der Bewertungsmethodik. Die Zusammenfassungen sind gegliedert nach Definition des Technologiefeldes, aktueller Stand der Technologie, ausgewählte Bewertungskriterien und F&E-Empfehlungen

    Betriebliches Datenmanagement und FMIS: Machbarkeitsstudie für „Betriebliches Datenmanagement und Farm-Management-Information-System (FMIS)“ in sächsischen Landwirtschaftsbetrieben

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    Die Studie gibt Auskunft über den Umgang mit Medienbrüchen und die Darstellung von Kennzahlen zur Unternehmenssteuerung in der Landwirtschaft. Datenvernetzung und Visualisierung sind die Voraussetzung zur Etablierung von „smart farming“ in der Praxis. In der Landwirtschaft kann ein hybrides Datenmanagement zu der Vernetzung betrieblicher Software beitragen. Dies besteht aus Datenhubs, Datenroutern und bilateralen Schnittstellen. Die Ergebnisse sind richtungsweisend für landwirtschaftliche Unternehmen, Softwareanbieter, Behörden und alle weiteren Teilnehmer im digitalen Ökosystem der Agrardomäne. Redaktionsschluss: 10.10.202

    B cells orchestrate tolerance to the neuromyelitis optica autoantigen AQP4

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    Neuromyelitis optica is a paradigmatic autoimmune disease of the central nervous system, in which the water-channel protein AQP4 is the target antigen1. The immunopathology in neuromyelitis optica is largely driven by autoantibodies to AQP42. However, the T cell response that is required for the generation of these anti-AQP4 antibodies is not well understood. Here we show that B cells endogenously express AQP4 in response to activation with anti-CD40 and IL-21 and are able to present their endogenous AQP4 to T cells with an AQP4-specific T cell receptor (TCR). A population of thymic B cells emulates a CD40-stimulated B cell transcriptome, including AQP4 (in mice and humans), and efficiently purges the thymic TCR repertoire of AQP4-reactive clones. Genetic ablation of Aqp4 in B cells rescues AQP4-specific TCRs despite sufficient expression of AQP4 in medullary thymic epithelial cells, and B-cell-conditional AQP4-deficient mice are fully competent to raise AQP4-specific antibodies in productive germinal-centre responses. Thus, the negative selection of AQP4-specific thymocytes is dependent on the expression and presentation of AQP4 by thymic B cells. As AQP4 is expressed in B cells in a CD40-dependent (but not AIRE-dependent) manner, we propose that thymic B cells might tolerize against a group of germinal-centre-associated antigens, including disease-relevant autoantigens such as AQP4. The immune system is tolerized against the neuromyelitis optica autoantigen AQP4 by thymic B cells, which present their endogenous AQP4 to AQP4-reactive thymocytes

    How does neopatrimonialism affect the African state? The case of tax collection in Zambia

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    Following the neopatrimonialism paradigm, it can be hypothesised that in African states informal politics of the rulers infringe on the collection of taxes and in turn reduce state revenue. This article tests this proposition for the case of Zambia. Neopatrimonial continuity in the country is evidenced by three factors : the concentration of political power, the award of personal favours, and the misuse of state resources. Despite this continuity, the revenue performance increased considerably with the creation of the semi-autonomous Zambia Revenue Authority. Donor pressure has been the most important intervening variable accounting for this improvement. Yet, strengthening the collection of central state revenue has been consistent with a neopatrimonial rationale, and may even have fed neopatrimonialism overall, by providing increased resources for particularistic expenditure
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