879 research outputs found

    Presence of atrial natriuretic factor prohormone in enterochromaffin cells of the human large intestine

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    Atrial natriuretic factor is a hormone intimately involved in water and salt homeostasis. The heart constitutes the major but not exclusive site of synthesis of this hormone. Among other functions, the gastrointestinal tract has endocrine functions, plays an important role in volume regulation of the body, and seems to be a target organ for atrial natriuretic factor. Therefore, the presence of atrial natriuretic factor was investigated in the human gut. Immunoreactive atrial natriuretic factor was found in intraoperatively obtained samples of normal human colon. Acidic extracts of human large intestine contained about 0.4 pmol/g wet wt of atrial natriuretic factor. Analysis of atrial natriuretic factor immunoreactivity by gel-filtration and reverse-phase high-performance liquid chromatography showed that about 65% of the immunoreactivity corresponded to the atrial natriuretic factor phohormone and about 35% corresponded to the C-terminal ANF99-126. Immunohistochemistry showed atrial natriuretic factor prohormone location in enterochromaffin cells of the colon mucosa. Altogether, these findings show the presence of atrial natriuretic factor prohormone in enterochromaffin cells of the human large intestine and may suggest this organ as a site of atrial natriuretic factor synthesis in humans

    Intramural duodenal hematoma: clinical course and imaging findings

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    Background: Intramural duodenal hematoma is a rare condition. Different imaging modalities are at hand for diagnosis. Purpose: To identify patients with intramural duodenal hematoma and report imaging findings and clinical courses. Material and Methods: Typical imaging patterns using ultrasound, computed tomography, and magnetic resonance imaging were carried out on 10 patients. Results: The mean patient age was 7.5 years. The average disease duration was 13 months. Clinical signs of improvement were observed within 16 days. Residues were still detectable at long-term follow-up. Conclusion: For patients with intramural duodenal wall hematoma, diagnosis should be considered early. Typical imaging findings should be known to ensure optimal treatment

    Konzeption und prototypische Realisierung eines Informationssystems fĂŒr das Prozeßmonitoring und -controlling

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    Durch die Überwachung der aktuellen Prozeßstatus (Prozeßmonitoring) sowie die Verdichtung und GegenĂŒberstellung dieser Istdaten mit Solldaten (Prozeßcontrolling) wird die Bewertung der ProzeßqualitĂ€t möglich. Zur informationstechnischen UnterstĂŒtzung dieser Aufgaben dienen Prozeßinformationssysteme. In diesem Arbeitsbericht werden nach einer Einordnung dieser Aufgaben in einem Vorgehensmodell des Prozeßmanagements Intention und Aufbau von Prozeßinformationssystemen beschrieben. Konkretisiert werden die AusfĂŒhrungen durch die Vorstellung des Prototypen PISA, dessen Architektur und FunktionalitĂ€t erlĂ€utert werden.<br/

    5d-5f Electric-multipole Transitions in Uranium Dioxide Probed by Non-resonant Inelastic X-ray Scattering

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    Non-resonant inelastic x ray scattering (NIXS) experiments have been performed to probe the 5d-5f electronic transitions at the uranium O(4,5) absorption edges in uranium dioxide. For small values of the scattering vector q, the spectra are dominated by dipole-allowed transitions encapsulated within the giant resonance, whereas for higher values of q the multipolar transitions of rank 3 and 5 give rise to strong and well-defined multiplet structure in the pre-edge region. The origin of the observed non-dipole multiplet structures is explained on the basis of many-electron atomic spectral calculations. The results obtained demonstrate the high potential of NIXS as a bulk-sensitive technique for the characterization of the electronic properties of actinide materials.Comment: Submitted to Physical Review Letters on 31 December 200

    What Can We Learn from Quality Requirements in ISO/TS 82304-2 for Evaluating Conversational Agents in Healthcare?

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    Evaluating conversational agents (CA) that are supposed to be applied in healthcare and ensuring their quality is essential to avoid patient harm. However, most researchers only study usability and use the CA in clinical trials before conducting such careful evaluation. In previous work, consensus on metrics for evaluating healthcare CA have been found. However, the metrics are still too generic to form an evaluation framework. In this work, we try to link the ISO technical specification ISO/TS 82304-2 Quality Requirements for Health and Wellness Apps to the set of metrics to come a step closer towards an evaluation framework. We identify three links between ISO requirements and the set of metrics, namely accessibility, usability, and security. Although the technical specification rather lists aspects to be considered during development instead of concrete metrics for studying the quality, we can link to some aspects that are also of interest for health CA evaluation. For example, measuring the readability for ensuring accessibility or implementing the Web Content Accessibility Guidelines are two aspects of relevance for health CA

    Modelling of Breathing Phenomena within Large Storage Tanks During Rapid Cooling with Ambient Rain

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    Storage tanks in the process industry are often filled with hazardous media under atmospheric conditions. Due to heavy rain showers the tank content is cooled down and the system temperature drops significantly. During this process the pressure decreases and condensate forms. It is known that “vacuum” can cause serious damage on storage tanks due to undersized venting devices. To describe the transient storage tank behaviour modelling of complex inbreathing fluid flow, heat transfer, condensation, retrograde gas states or thermodynamic nonequilibrium is needed. Conservative sizing of protection devices for storage tanks is only possible if the influencing phenomena and their couplings are well understood. The influence of heat transfer through film condensation as an example phenomenon is mentioned by several authors in science and industry, but not included in common models. With the new approach of ARTEM (advanced reactor and storage tank emission model) phenomena, like condensation or complex heat transfer will be considered for transient vessel venting. Experience and preparatory work have shown that detailed modelling with computational fluid dynamic (CFD) tools is necessary to analyse the complex multiscale phenomena accurately and in sufficient detail. As a first step towards ARTEM, an analytical parameter study on tank breathing with common sizing models and a CFD study on heat transfer through a tank wall is presented

    The INE-beamline for actinide research at ANKA

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    Polarised epithelial monolayers of the gastric mucosa reveal insights into mucosal homeostasis and defence against infection

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    Objective Helicobacter pylori causes life-long colonisation of the gastric mucosa, leading to chronic inflammation with increased risk of gastric cancer. Research on the pathogenesis of this infection would strongly benefit from an authentic human in vitro model. Design Antrum-derived gastric glands from surgery specimens served to establish polarised epithelial monolayers via a transient air–liquid interface culture stage to study cross-talk with H. pylori and the adjacent stroma. Results The resulting ‘mucosoid cultures’, so named because they recapitulate key characteristics of the gastric mucosa, represent normal stem cell-driven cultures that can be passaged for months. These highly polarised columnar epithelial layers encompass the various gastric antral cell types and secrete mucus at the apical surface. By default, they differentiate towards a foveolar, MUC5AC-producing phenotype, whereas Wnt signalling stimulates proliferation of MUC6-producing cells and preserves stemness—reminiscent of the gland base. Stromal cells from the lamina propria secrete Wnt inhibitors, antagonising stem-cell niche signalling and inducing differentiation. On infection with H. pylori, a strong inflammatory response is induced preferentially in the undifferentiated basal cell phenotype. Infection of cultures for several weeks produces foci of viable bacteria and a persistent inflammatory condition, while the secreted mucus establishes a barrier that only few bacteria manage to overcome. Conclusion Gastric mucosoid cultures faithfully reproduce the features of normal human gastric epithelium, enabling new approaches for investigating the interaction of H. pylori with the epithelial surface and the cross-talk with the basolateral stromal compartment. Our observations provide striking insights in the regulatory circuits of inflammation and defence.</p

    Electronic structure and chemical bonding in Ti2AlC investigated by soft x-ray emission spectroscopy

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    The electronic structure of the nanolaminated transition metal carbide Ti2AlC has been investigated by bulk-sensitive soft x-ray emission spectroscopy. The measured Ti L, C K and Al L emission spectra are compared with calculated spectra using ab initio density-functional theory including dipole matrix elements. The detailed investigation of the electronic structure and chemical bonding provides increased understanding of the physical properties of this type of nanolaminates. Three different types of bond regions are identified; the relatively weak Ti 3d - Al 3p hybridization 1 eV below the Fermi level, and the Ti 3d - C 2p and Ti 3d - C 2s hybridizations which are stronger and deeper in energy are observed around 2.5 eV and 10 eV below the Fermi level, respectively. A strongly modified spectral shape of the 3s final states in comparison to pure Al is detected for the buried Al monolayers indirectly reflecting the Ti 3d - Al 3p hybridization. The differences between the electronic and crystal structures of Ti2AlC, Ti3AlC2 and TiC are discussed in relation to the number of Al layers per Ti layer in the two former systems and the corresponding change of the unusual materials properties.Comment: 14 pages, 7 figures; PACS:78.70.En, 71.15.Mb, 71.20.-
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