1,721,162 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development of murine Fab-Multimers for selection and functional characterization of reversibly stained regulatory T cells
No full textIn dieser Arbeit wurden, basierend auf Streptamer-Technologie, erstmals murine Fab-Multimere gegen CD4 und CD25 entwickelt, um regulatorische T-Zellen (Tregs) der Maus reversibel anfärben und anreichern zu können. Die neuen Reagenzien wurden mit konventioneller Antikörperfärbung verglichen und erzielten in durchflusszytometrischen Analysen zu Färbung, Reinheit und Spezifität stets gleichwertige oder bessere Ergebnisse. Zusätzlich lassen Suppressions- und Proliferationsanalysen sowie adoptive Zelltransfers auf eine tendenziell geringere funktionelle Beeinträchtigung reversibel gefärbter Tregs schließen. Diese Daten können dazu beitragen, Tregs zelltherapeutisch besser nutzbar zu machen.In this dissertation, for the first time murine Fab-multimers against CD4 and CD25 were developed using Streptamer-technology to reversibly stain and enrich murine regulatory T cells (Tregs). The new reagents were compared to conventional antibody staining and analyzed by flow cytometry, obtaining equal or better results in staining qualities, purity and specificity. In addition suppression assays, proliferation experiments and adoptive cell transfer suggested a less functional impairment of reversibly stained Tregs. These data might contribute to bringing purified Tregs to clinical application
Transfer of the koff-rate-assay on CD8+ T cells from the murine to the human system
Get PDFIn dieser Arbeit wurde der koff-rate-Assay vom murinen auf das humane System übertragen. Der Assay ist eine neue Methode zur Messung der Dissoziationskinetiken von monomeren pMHCI-Molekülen von T-Zell-Rezeptoren (TCR) an lebenden CD8+ T-Zellen. Reversibel polymerisierte, fluoreszenzmarkierte pMHC-Moleküle binden stabil an TCR. Nach schlagartiger Monomerisierung diffundieren die pMHC-Moleküle mit messbaren Kinetiken von den TCR ab. Da der Assay nicht analog übertragen werden konnte, wurden die Probleme analysiert und ein Lösungsansatz entwickelt.In this work the koff-rate-assay has been transferred from the murine to the human setup. The assay is a new method to measure dissociation kinetics of monomeric pMHCI molecules from T cell receptors (TCR) on living CD8+ T cells. Reversibly polymerized, fluorescence-marked pMHC molecules bind stably to TCR. After sudden monomerization the pMHC molecules dissociate from the TCR with distinct kinetics that can be measured. Since an analogous transfer to the human system was not possible, the problems were analyzed and a new approach was developed
Formation and immunomodulatory function of meningeal B-cell aggregates in progressive CNS autoimmunity
Get PDFMeningeal B lymphocyte aggregates have been described in autopsy material of patients with chronic Multiple Sclerosis. The presence of meningeal B cell aggregates has been correlated with worse disease. However, the functional role of these meningeal B cell aggregates is not understood. Here, we use a mouse model of Multiple Sclerosis, the spontaneous opticospinal encephalomyelitis model, which is built on the double transgenic expression of myelin oligodendrocyte glycoprotein-specific T cell- and B cell-receptors, to show that the formation of meningeal B cell aggregates is dependent on the expression of α4 integrins by antigen-specific T cells. T cell-conditional genetic ablation of α4 integrins in opticospinal encephalomyelitis mice impaired the formation of meningeal B cell aggregates, and surprisingly, led to a higher disease incidence as compared to opticospinal encephalomyelitis mice with α4 integrin-sufficient T cells. B cell-conditional ablation of α4 integrins in opticospinal encephalomyelitis mice resulted in the entire abrogation of the formation of meningeal B cell aggregates, and opticospinal encephalomyelitis mice with α4 integrin-deficient B cells suffered from a higher disease burden than regular opticospinal encephalomyelitis mice. While anti-CD20 antibody-mediated systemic depletion of B cells in opticospinal encephalomyelitis mice after onset of disease failed to efficiently decrease meningeal B cell aggregates without significantly modulating disease progression, treatment with anti-CD19 chimeric antigen receptor-T cells eliminated meningeal B cell aggregates and exacerbated clinical disease in opticospinal encephalomyelitis mice. Since about 20 percent of B cells in organised meningeal B cell aggregates produced either IL-10 or IL-35, we propose that meningeal B cell aggregates might also have an immunoregulatory function as to the immunopathology in adjacent spinal cord white matter. The immunoregulatory function of meningeal B cell aggregates needs to be considered when designing highly efficient therapies directed against meningeal B cell aggregates for clinical application in Multiple Sclerosis
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Analyzing the development of adaptive immune responses derived from single naïve CD8+ T cells
No full textIn der vorliegenden Dissertation wurde die Entwicklung von CD8+ T-Zell-Immunantworten ausgehend von einzelnen naiven T-Zellen untersucht. Anzahl und Phänotyp der Nachkommen, die aus einzelnen T-Zellen hervorgingen variierte deutlich. Gemeinsam ergaben diese variablen Zellschicksale jedoch ein vorhersagbares, an das Infektionsgeschehen angepasstes Muster. Die Robustheit der CD8+ T-Zell-Immunantwort wird also nicht auf Ebene der einzelnen in die Immunantwort rekrutierten T-Zelle etabliert, sondern erst durch die Einbeziehung einer ausreichend großen naiven T-Zellpopulation gewährleistet.In the present dissertation development of CD8+ T cell immune responses derived from single naïve T cells was studied. Number and phenotype of offspring derived from a single naïve T cell varied considerably. However, together these varying single cell fates created predictable response patterns, tailored to fighting the infectious agent. Thus, robustness of CD8+ T cell immune responses is not established by individual naïve T cells but rather guaranteed by recruitment of naïve T cell populations
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