Untersuchung von Relevanzeigenschaften in einem kontrollierten Eytracking-Experiment

In diesem Artikel wird ein Eyetracking-Experiment beschrieben, bei dem untersucht wurde, wann und auf Basis welcher Informationen Relevanzentscheidungen bei der themenbezogenen Dokumentenbewertung fallen und welche Faktoren auf die Relevanzentscheidung einwirken. Nach einer kurzen Einführung werden einschlägige Studien aufgeführt, in denen Blickverfolgung (Eye tracking) als Untersuchungsmethode für Interaktionsverhalten mit Ergebnislisten (information seeking behaviour) verwendet wurde. Nutzerverhalten wird hierbei vor allem durch unterschiedliche Aufgaben-Typen, durch unterschiedlich dargestellte Informationen und durch den Rang eines Ergebnisses auf der Trefferliste beeinflusst. Durch Eyetracking-Untersuchungen lassen sich Nutzer außerdem in verschiedene Klassen von Bewertungs- und Lesetypen einordnen. Diese Informationen können als implizites Feedback genutzt werden, um so die Suche zu personalisieren und um die Relevanz von Suchergebnissen ohne aktives Zutun des Users zu erhöhen. In einem explorativen Eyetracking-Experiment mit zwölf Studenten der Hochschule Darmstadt werden anhand der Länge der Gesamtbewertung, Anzahl der Fixationen, Anzahl der besuchten Metadatenelemente und Länge des Scanpfades zwei typische Bewertungstypen identifiziert. Das Metadatenfeld Abstract wird im Experiment zuverlässig als wichtigste Dokumenteigenschaft für die Zuteilung von Relevanz ermittelt. (Autorenreferat)The article describes an eyetracking experiment which examines relevance judgements within the context of subject-related document assessments. We analyze in the study on what information the judgements of our test persons are based on and which document specific properties influence the relevance decisions. In the state of the art the authors present relevant studies that use eyetracking methodology as a research method to investigate information seeking behaviour models. The three factors that particularly influence user behaviour are: different task types, search results presentation, and document ranking. Furthermore, the results of these eyetracking studies help us to classify users into typical evaluation and reading types. This information can then be used as implicit feedback to personalize the search. Relevance of search results could thus be improved without any further involvement by the users. In an exploratory eyetracking experiment with twelve students from the University of Applied Sciences in Darmstadt, we were able to identify two typical evaluation types, based on total length of the evaluation, number of fixations, number of visited metadata elements and length of the scan path. This experiment shows that the metadata field abstract is clearly the most important document property to assign topical relevance to scientific articles. (author's abstract

Influence of ecological optimized manufacturing on the production costs of C/C structures using CVI technology

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Biochemical characterization of trans-sialidase TS1 variants from Trypanosoma congolense

<p>Abstract</p> <p>Background</p> <p>Animal African trypanosomiasis, sleeping sickness in humans and Nagana in cattle, is a resurgent disease in Africa caused by <it>Trypanosoma </it>parasites. Trans-sialidases expressed by trypanosomes play an important role in the infection cycle of insects and mammals. Whereas trans-sialidases of other trypanosomes like the American <it>T. cruzi </it>are well investigated, relatively little research has been done on these enzymes of <it>T. congolense</it>.</p> <p>Results</p> <p>Based on a partial sequence and an open reading frame in the WTSI database, DNA sequences encoding for eleven <it>T. congolense </it>trans-sialidase 1 variants with 96.3% overall amino acid identity were amplified. Trans-sialidase 1 variants were expressed as recombinant proteins, isolated and assayed for trans-sialylation activity. The purified proteins produced α2,3-sialyllactose from lactose by desialylating fetuin, clearly demonstrating their trans-sialidase activity. Using an HPLC-based assay, substrate specificities and kinetic parameters of two variants were characterized in detail indicating differences in substrate specificities for lactose, fetuin and synthetic substrates. Both enzymes were able to sialylate asialofetuin to an extent, which was sufficient to reconstitute binding sites for Siglec-4. A mass spectrometric analysis of the sialylation pattern of glycopeptides from fetuin revealed clear but generally similar changes in the sialylation pattern of the <it>N</it>-glycans on fetuin catalyzed by the trans-sialidases investigated.</p> <p>Conclusions</p> <p>The identification and characterization of a trans-sialidase gene family of the African parasite <it>T. congolense </it>has opened new perspectives for investigating the biological role of these enzymes in Nagana and sleeping sickness. Based on this study it will be interesting to address the expression pattern of these genes and their activities in the different stages of the parasite in its infection cycle. Furthermore, these trans-sialidases have the biotechnological potential to be used for enzymatic modification of sialylated glycoconjugates.</p

Low‐voltage shock impedance measurements: A false sense of security

Background: Implantable cardioverter defibrillators use low-voltage shock impedance measurements to monitor the lead integrity. However, previous case reports suggest that low-voltage shock impedance measurements may fail to detect insulation breaches that can cause life-threatening electrical short circuits. Methods and results: We report six cases of insulation breaches in transvenous defibrillation leads that were not obvious during standard interrogations and testing of the lead beforehand. In two cases, an electrical short circuit during commanded shock delivery for internal electrical cardioversion resulted in a total damage of the ICD generator. In one of these cases, commanded shock delivery induced ventricular fibrillation, which required external defibrillation. In two cases, a shock due to ventricular tachycardia was aborted as the shock impedance was less than 20 Ω. However, in both cases the tiny residual shock energy terminated the ventricular tachycardia. In contrast, in one case the residual energy of the aborted shock did not end ventricular fibrillation induced at defibrillator threshold testing. In one case, the ICD indicated an error code for a short circuit condition detected during an adequate shock delivery. Conclusions: This case series illustrates that low-voltage shock impedance measurements can fail to detect insulation breaches. These data suggest that in patients without a contraindication, traditional defibrillator threshold testing or high voltage synchronized shock at the time of device replacement should be considered

Mode of action of antimicrobial peptides: long and short amphipathic alpha-helixes use different mechanisms

1 pag. -- 58th Annual Meeting of the Biophysical-Societ

Let's play with Statistics!: Implementierung einer studierendenzentrierten multimedialen Lernumgebung unter Einsatz von R-Shiny Apps und Videos

Das E-Learning Modul MUVE-STAT (Statistische Grundbegriffe und Grundlagen multivariater Verfahren) ermöglicht Psychologiestudierenden einen anwendungsorientierten und interaktiven Erwerb statistischer Methodenkenntnisse. Die Inhalte umfassen anschauliche Darstellungen statistischer Grundbegriffe bis hin zur Anwendung multivariater Verfahren. MUVE-STAT soll Lehrende und Studierende in unterschiedlichen, insbesondere in interdisziplinären Bachelorstudiengängen unterstützen und eine erfolgreiche Fortsetzung des Studiums im Rahmen eines konsekutiven Masterstudiengangs, wie dem Studiengang „Psychologie: Human Performance in Socio- Technical Systems” (HPSTS) an der TU Dresden, gewährleisten

Increased PD-L1 expression in radioresistant HNSCC cell lines after irradiation affects cell proliferation due to inactivation of GSK-3beta

At present, targeting PD-1/PD-L1 axis for immune checkpoint inhibition has improved treatment of various tumor entities, including head and neck squamous cell carcinoma (HNSCC). However, one part of the patient cohort still shows little improvement or even hyperprogression. We established three radioresistant (RR) and three radiosensitive (RS) HNSCC cell lines. RR cells showed prolonged survival as well as delayed and diminished apoptosis after irradiation with vimentin expression but no E-cadherin expression, whereas RS cell lines died early and exhibited early apoptosis after irradiation and high vimentin expression. Here, we present results demonstrating differential basal PD-L1 gene and protein expression in RR and RS HNSCC cell lines. Moreover, we observed a radiation dose dependent increase of total PD-L1 protein expression in RR cell lines up to 96h after irradiation compared to non-irradiated (non-IRR) cells. We found a significant GSK-3beta phosphorylation, resulting in an inactivation, after irradiation of RR cell lines. Co-immunoprecipitation experiments revealed decreased interaction of GSK-3beta with PD-L1 in non-IRR compared to irradiated (IRR) RR cells leading to PD-L1 stabilization in RR cells. PD-L1 knockdown in RR cells showed a strong decrease in cell survival. In summary, our results suggest an irradiation dependent increase in basal PD-L1 expression in RR HNSCC cell lines via GSK-3beta inactivation

TNF-related apoptosis-inducing ligand, interferon gamma-induced protein 10, and C-reactive protein in predicting the progression of SARS-CoV-2 infection : a prospective cohort study

Background: Early prognostication of COVID-19 severity will potentially improve patient care. Biomarkers, such as TNF-related apoptosis-inducing ligand (TRAIL), interferon gamma-induced protein 10 (IP-10), and C-reactive protein (CRP), might represent possible tools for point-of-care testing and severity prediction. Methods: In this prospective cohort study, we analyzed serum levels of TRAIL, IP-10, and CRP in patients with COVID-19, compared them with control subjects, and investigated the association with disease sever ity. Results: A total of 899 measurements were performed in 132 patients (mean age 64 years, 40.2% females). Among patients with COVID-19, TRAIL levels were lower (49.5 vs 87 pg/ml, P = 0.0142), whereas IP-10 and CRP showed higher levels (667.5 vs 127 pg/ml, P <0.001; 75.3 vs 1.6 mg/l, P <0.001) than healthy controls. TRAIL yielded an inverse correlation with length of hospital and intensive care unit (ICU) stay, Simplified Acute Physiology Score II, and National Early Warning Score, and IP-10 showed a positive cor relation with disease severity. Multivariable regression revealed that obesity (adjusted odds ratio [aOR] 5.434, 95% confidence interval [CI] 1.005-29.38), CRP (aOR 1.014, 95% CI 1.002-1.027), and peak IP-10 (aOR 1.001, 95% CI 1.00-1.002) were independent predictors of in-ICU mortality