233 research outputs found

    A Theory-Based Approach for a Modular System of Interactive Decision Aids

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    In web stores, a large amount of product information is easily available for consumers. This often leads to information overload on the consumer-side which decreases user-satisfaction and can cause purchase deferral. Therefore, our goal is to prevent consumers from information overload by supporting the cumbersome process of comparing and evaluating products. We propose easy to understand, interactive decision aids, called interactive information management tools such as filtering, sorting and scoring. The contribution of this paper is to (1) retrieve guidelines for designing such tools from both literature on decision behavior research and information systems, and (2) build a prototype following these guidelines. The prototype is evaluated in two usability studies

    Psychoseähnliches Erleben, Depressivität und Schlafparameter bei Patienten mit Schlafapnoe-Syndrom

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    Psychoseähnliche Erlebnisse sind in der Bevölkerung weit verbreitet und gelten per se nicht als pathologisch. Ein gestörter Schlaf wird häufig bei Patienten mit Schizophrenie, aber auch bei Menschen mit psychoseähnlichem Erleben, beobachtet. Die Ziele der Studie waren, psychoseähnliche Symptome bei Patienten mit Schlafapnoe-Syndrom (OSA) zu bestimmen und diese über Veränderungen der Schlafparameter nachzuvollziehen. Überdies wurde die nächtliche Gedächtniskonsolidierung in Zusammenhang mit Schlafparametern untersucht. Wir verglichen Patienten mit OSA (n=42) mit gesunden Kontrollprobanden (n=33). Die Beurteilung psychoseähnlicher Erlebnisse erfolgte mit der Magical Ideation Scale (MIS) und dem Peters et al. Delusions Inventory (PDI-21). Zum Erfassen von Depressionen diente das Beck-Depressions-Inventar-II (BDI-II). Die nächtliche Gedächtniskonsolidierung der Patienten mit OSA wurde mit dem verbalen Lern- und Merkfähigkeitstest (VLMT) gemessen. In der Auswertung zeigten die Patienten mit OSA gesteigerte psychoseähnliche Erlebnisse im Sinne eines statistischen Trends im PDI-21. Zudem ließ sich eine erhöhte Depressivität der Patienten feststellen. Wichtig war auch die signifikant positive Korrelation von verlängertem REM-Schlaf mit gesteigerter Depressivität und Wahnüberzeugungen. Bei der Gedächtnisleistung ließ sich eine negative Assoziation mit dem Schweregrad der OSA nachweisen. Diese Befunde bedürfen weiterer Untersuchungen von psychoseähnlichen Erlebnissen bei verschiedenen Schlafstörungen. Bei Patienten mit OSA müssen weitere Studien zeigen, inwieweit die Reduktion der depressiven Symptomatik und Verbesserung der Gedächtnisleistung unter Therapie stattfinden kann

    Molecular constituents of the extracellular matrix in rat liver mounting a hepatic progenitor cell response for tissue repair

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    BACKGROUND: Tissue repair in the adult mammalian liver occurs in two distinct processes, referred to as the first and second tiers of defense. We undertook to characterize the changes in molecular constituents of the extracellular matrix when hepatic progenitor cells (HPCs) respond in a second tier of defense to liver injury. RESULTS: We used transcriptional profiling on rat livers responding by a first tier (surgical removal of 70% of the liver mass (PHx protocol)) and a second tier (70% hepatectomy combined with exposure to 2-acetylaminofluorene (AAF/PHx protocol)) of defense to liver injury and compared the transcriptional signatures in untreated rat liver (control) with those from livers of day 1, day 5 and day 9 post hepatectomy in both protocols. Numerous transcripts encoding specific subunits of collagens, laminins, integrins, and various other extracellular matrix structural components were differentially up- or down-modulated (P < 0.01). The levels of a number of transcripts were significantly up-modulated, mainly in the second tier of defense (Agrn, Bgn, Fbn1, Col4a1, Col8a1, Col9a3, Lama5, Lamb1, Lamb2, Itga4, Igtb2, Itgb4, Itgb6, Nid2), and their signal intensities showed a strong or very strong correlation with Krt1-19, a well-established marker of a ductular/HPC reaction. Furthermore, a significant up-modulation and very strong correlation between the transcriptional profiles of Krt1-19 and St14 encoding matriptase, a component of a novel protease system, was found in the second tier of defense. Real-time PCR confirmed the modulation of St14 transcript levels and strong correlation to Krt-19 and also showed a significant up-modulation and strong correlation to Spint1 encoding HAI-1, a cognate inhibitor of matriptase. Immunodetection and three-dimensional reconstructions showed that laminin, Collagen1a1, agrin and nidogen1 surrounded bile ducts, proliferating cholangiocytes, and HPCs in ductular reactions regardless of the nature of defense. Similarly, matriptase and HAI-1 were expressed in cholangiocytes regardless of the tier of defense, but in the second tier of defense, a subpopulation of HPCs in ductular reactions co-expressed HAI-1 and the fetal hepatocyte marker Dlk1. CONCLUSION: Transcriptional profiling and immunodetection, including three-dimensional reconstruction, generated a detailed overview of the extracellular matrix constituents expressed in a second tier of defense to liver injury

    Three-dimensional preforming via wet-laid nonwoven technology for ceramic matrix composites

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    In this study, a new 3D preforming method was developed using wet-laid nonwoven technology, for application in manufacturing ceramic matrix composites (CMC). For this purpose, a process setup was developed and tested on an example geometry (radome). HTS 45 carbon fibers and Nextel610 alumina fibers were used for the preforming. The resulting C/C-SiC and OXIPOL materials were mechanically characterized and the microstructure was investigated. A radome was manufactured from each material and subjected to DLR's L2K and VMK wind tunnels. The tests have been successful with the C/C-SiC and OXIPOL radome. Overall the application-oriented tests show that load-bearing components can be produced with the newly developed preform method and that they also prove themselves in the application. The knowledge gained, demonstrates the potential of the 3D wet-laid nonwoven preforming method and represents a new possibility for CMC production with complex shapes

    Relative recency influences object-in-context memory

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    In two experiments rats received training on an object-in-context (OIC) task, in which they received preexposure to object A in context x, followed by exposure to object B in context y. In a subsequent test both A and B are presented in either context x or context y. Usually more exploration is seen of the object that has not previously been paired with the test context, an effect attributed to the ability to remember where an object was encountered. However, in the typical version of this task, object A has also been encountered less recently than object B at test. This is precisely the arrangement in tests of ‘relatively recency’ (RR), in which more remotely presented objects are explored more than objects experienced more recently. RR could contaminate performance on the OIC task, by enhancing the OIC effect when animals are tested in context y, and masking it when the test is in context x. This possibility was examined in two experiments, and evidence for superior performance in context y was obtained. The implications of this for theoretical interpretations of recognition memory and the procedures used to explore it are discussed
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