1,720,975 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
From DNA methylation to protein : Selection and evaluation of regulated targets in a human cerebral ischemia in vitro model of the blood-brain barrier
No full textMaster thesis - University of Veterinary Medicine Vienna - 2021Background: Stroke and traumatic brain injury (TBI) are two threatening disorders of the central nervous system (CNS) that in case of survival usually result in serious permanent disabilities. Course of both diseases is accompanied by cerebral ischemia. The blood-brain barrier (BBB) represents a neuroprotective border formed by brain capillary endothelial cells. Loss of the BBB integrity is a consequence of cerebral ischemia. Recent studies demonstrated that the restorative processes initiated at the BBB after cerebral ischemia are regulated by epigenetic mechanisms, namely DNA methylation. The aim of this study was to evaluate the effect of oxygen-glucose deprivation (OGD) on the expression and function of targets selected from DNA methylation arrays of OGD treated human cerebral microvascular endothelial cell line (hCMEC/D3).
Methods: Targets were chosen based on Kegg Pathway Database, Gene Set Enrichment Analysis, and STRING database analysis. Their expression was examined at mRNA and protein level. For analysis at mRNA level, RNA samples from different conditions were used: hCMEC/D3 in co-culture with astrocytes and pericytes, hiPS-EC in co-culture with astrocytes and pericytes, and human TBI biopsy samples. For analysis at protein level, hCMEC/D3 mono-culture was exposed to OGD at 0.1% oxygen for 5 hours followed by recovery phase for additional 19 hours. For inhibitor studies, transwell models with hCMEC/D3 cells in co-culture with glioma C6 cells were subjected to 5-hour OGD treatment at 0.1% oxygen.
Results: Selected 13 regulated targets showed significant changes at mRNA level as well as at protein level in different experimental set-ups after two distinct OGD timepoints. Data analysis of qPCRs with human TBI biopsy samples from four patients revealed changes in the expression of DNA methylation targets over the time. Inhibitor studies performed with SGK1 inhibitor demonstrated greater damage and injury to the BBB when applied at higher concentrations, while displayed powerful protective response upon the cells in lower concentrations.
Conclusion: Epigenetics, namely DNA methylation, emerges as a valuable tool for understanding complex processes arising at the BBB during and after cerebral ischemia. Identification and characterization of novel DNA methylation targets may help to tackle currently restricted treatment strategies as well as to develop means of restoring permanent damage resulting from stroke and TBI in case of survival.Masterarbeit - Veterinärmedizinische Universität Wien - 2021Hintergrund: Schlaganfall und Schädel-Hirn Trauma (SHT) sind zwei bedrohliche Erkrankungen des Zentralnervensystems, die im Falle des Überlebens normalerweise zu schweren und dauerhaften Behinderungen führen. Beide Krankheiten werden von zerebraler Ischämie begleitet. Die Blut-Hirn-Schranke (BHS) stellt eine neuroprotektive Grenze dar, die durch Hirnkapillarendothelzellen gebildet wird. Der Verlust der BHS-Integrität ist eine Folge der zerebralen Ischämie. Jüngste Studien zeigten, dass die an der BHS nach zerebraler Ischämie initiierten restaurativen Prozesse von epigenetischen Mechanismen, nämlich DNA-Methylierung, reguliert sind. Ziel dieser Studie war es, den Effekt die Wirkung von Sauerstoff- und Glukoseentzug (SGE) auf die Expression und die Funktion der Ziele aus DNA-Methylierungsanordnungen der SGE-behandelten menschlichen, geistigen, mikrovaskulären Endothelzelllinie hCMEC/D3 auszuwerten.
Methoden: Die Ziele wurden basierend auf der KEGG-Pathway-Datenbank, der Gene-Set-Anreicherungsanalyse und der String-Datenbankanalyse ausgewählt. Ihre Expression wurde auf mRNA- und Eiweißebene untersucht. Für die Analyse auf mRNA-Ebene wurden RNA-Proben verschiedener Zustände verwendet: hCMEC/D3 in der Co-Kultur mit Astrozyten und Perizyten, hiPS-EC in Co-Kultur mit Astrozyten und Perizyten sowie Human-TBI-Biopsie-Proben. Bei der Analyse des Proteinspiegels wurde die hCMEC/D3-Monokultur für 5 Stunden SGE mit Sauerstoff von 0,1% ausgesetzt, gefolgt von einer Erholungsphase für weitere 19 Stunden. Bei Inhibitorstudien wurden Transwell-Modelle mit hCMEC/D3-Zellen in der Co-Kultur mit Gliom-C6-Zellen einer 5-stündigen SGE Behandlung mit 0,1% Sauerstoff unterzogen.
Ergebnisse: 13 ausgewählte regulierte Ziele zeigten erhebliche Veränderungen auf mRNA-Ebene sowie Veränderungen des Proteinspiegels in verschiedenen experimentellen Setups nach zwei unterschiedlichen SGE-Zeitpunkten. Die Datenanalyse von qPCRs mit humanen TBI-Biopsie-Proben von vier Patienten ergab Änderungen der Expression der DNA-Methylierungsziele über die Zeit. Inhibitorstudien, die mit SGK1-Inhibitor durchgeführt wurden, zeigten größere Beschädigungen und Verletzungen der BHS bei höheren Konzentrationen, während die Zellen in niedrigeren Konzentrationen eine leistungsstarke Schutzreaktion anzeigten.
Schlussfolgerung: Epigenetik, nämlich DNA-Methylierung, ist ein wertvolles Werkzeug, um komplexe Prozesse zu verstehen, die während und nach der zerebralen Ischämie auf der BHS ablaufen. Die Identifizierung und Charakterisierung neuartiger DNA-Methylierungsziele kann dazu beitragen, die derzeit eingeschränkten Behandlungsstrategien zu verbessern und dauerhafte Schäden zu bewältigen, welche sich aus Schlaganfall und SHT ergeben.Master thesis - University of Veterinary Medicine Vienna - 2021Background: Stroke and traumatic brain injury (TBI) are two threatening disorders of the central nervous system (CNS) that in case of survival usually result in serious permanent disabilities. Course of both diseases is accompanied by cerebral ischemia. The blood-brain barrier (BBB) represents a neuroprotective border formed by brain capillary endothelial cells. Loss of the BBB integrity is a consequence of cerebral ischemia. Recent studies demonstrated that the restorative processes initiated at the BBB after cerebral ischemia are regulated by epigenetic mechanisms, namely DNA methylation. The aim of this study was to evaluate the effect of oxygen-glucose deprivation (OGD) on the expression and function of targets selected from DNA methylation arrays of OGD treated human cerebral microvascular endothelial cell line (hCMEC/D3).
Methods: Targets were chosen based on Kegg Pathway Database, Gene Set Enrichment Analysis, and STRING database analysis. Their expression was examined at mRNA and protein level. For analysis at mRNA level, RNA samples from different conditions were used: hCMEC/D3 in co-culture with astrocytes and pericytes, hiPS-EC in co-culture with astrocytes and pericytes, and human TBI biopsy samples. For analysis at protein level, hCMEC/D3 mono-culture was exposed to OGD at 0.1% oxygen for 5 hours followed by recovery phase for additional 19 hours. For inhibitor studies, transwell models with hCMEC/D3 cells in co-culture with glioma C6 cells were subjected to 5-hour OGD treatment at 0.1% oxygen.
Results: Selected 13 regulated targets showed significant changes at mRNA level as well as at protein level in different experimental set-ups after two distinct OGD timepoints. Data analysis of qPCRs with human TBI biopsy samples from four patients revealed changes in the expression of DNA methylation targets over the time. Inhibitor studies performed with SGK1 inhibitor demonstrated greater damage and injury to the BBB when applied at higher concentrations, while displayed powerful protective response upon the cells in lower concentrations.
Conclusion: Epigenetics, namely DNA methylation, emerges as a valuable tool for understanding complex processes arising at the BBB during and after cerebral ischemia. Identification and characterization of novel DNA methylation targets may help to tackle currently restricted treatment strategies as well as to develop means of restoring permanent damage resulting from stroke and TBI in case of survival
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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
Overcoming tumour immune evasion : identifying novel negative regulators of MHC I in murine pancreatic ductal adenocarcinoma
No full textMasterarbeit - Veterinärmedizinische Universität Wien - 2020Der Haupthistokompatibilitätskomplex I (MHC I) bindet intrazellulär prozessierte Peptide, die zytotoxischen T Zellen an der Zelloberfläche präsentiert werden. Wenn ein Peptid durch Mutationen oder virale Infektionen verändert ist, können T Zellen bei Erkennung durch den T Zell Rezeptor eine Immunreaktion gegen die betroffene Zelle auslösen. Krebszellen umgehen diese Art der Immunkontrolle, indem Zellen mit mutiertem MHC I selektiert werden oder sie die Expression von MHC I supprimieren. Viele Krebspatienten weisen jedoch keine Mutationen auf, die mit einer Defizienz in der Präsentation von Antigenen assoziiert sind. Dies lässt vermuten, dass reversible Mechanismen in die Regulierung der MHC I Expression involviert sind. Um derartige negative Regulatoren zu identifizieren, wurde zuvor ein genomweiter CRISPR-Cas9 Screen in einer murinen Pankreas-Duktal-Adenokarzinom Zelllinie durchgeführt. Das Ziel dieser Masterarbeit war es, potentielle Treffer dieses Screens mittels Hochdurchsatz-Durchflusszytometrie zu validieren. Um die Regulierung von MHC I sowohl in entzündeten als auch in nicht entzündeten Tumormikroumgebungen nachzuahmen, stimulierten wir Knock-Out-Zellen entweder mit oder ohne dem pro-inflammatorischem Zytokin IFN-γ, welches zu einer stark gesteigerten Expression von MHC I führt. Zusätzlich zu kürzlich publizierten negativen Regulatoren von MHC I konnten Gene validiert werden, die in der Organisation von Chromatin, transkriptioneller Repression, Proteindegradierung sowie -glykosylierung involviert sind, oder deren Funktion nicht bekannt ist. In vorläufigen Experimenten konnten wir funktionelle Unterschiede in Bezug auf T Zellmediierte Kontrolle in vitro beobachten, obwohl die erzielten Effektgrößen durch den Knock- Out dieser Gene geringer waren als jene, die mit einer von IFN-γ stimulierten MHC I Expression erzielt werden können. Des Weiteren war die Hochregulierung von MHC I in einem Teil der validierten Knockout Zellen unabhängig von der Stimulation des IFN-γ Signalwegs und STAT1, was besonders diese Gene zu vielversprechenden therapeutischen Zielen in immunsupprimierten Tumoren sowie in Tumoren mit nicht funktionalem IFN-γ Signalweg macht.Master thesis - University of Veterinary Medicine Vienna - 2020The Major Histocompatibility Complex I (MHC I) is a cell surface protein that presents peptides derived from intracellular proteins to cytotoxic T cells. In case the presented peptide is immunogenic due to mutations or viral infections and recognized by the T cell receptor, an immune response will be induced. Cancer cells evade immune control and T cell mediated killing via the loss or downregulation of MHC I. The absence of mutations associated with antigen presentation in many patients suggests that reversible mechanisms are involved in the downregulation of MHC I. In order to identify negative regulators of MHC I expression, a genome-wide CRISPR-Cas9 knockout screen was performed previously in a murine pancreatic ductal adenocarcinoma model. The aim of this Masters’ thesis was to validate potential hits of this screen using a large-scale flow cytometry-based approach. To mimic MHC I regulation in inflamed as well as non-inflamed tumour microenvironments, we knocked out candidate genes in cells and treated them either with or without the pro-inflammatory cytokine IFN-γ, which strongly upregulates MHC I expression. In addition to recently published negative regulators of MHC I, we could validate genes that are involved in chromatin organization, transcriptional repression, protein degradation and glycosylation, or are functionally uncharacterized. We could observe functional differences in terms of susceptibility to T cell-mediated killing in vitro in preliminary assays, although the effect sizes we observed upon knockout of these genes were smaller than those of a direct IFN-γ-mediated MHC I upregulation. Furthermore, the upregulation of MHC I in a subset of the highest scoring knockout cells is independent of an IFN-γ stimulation as well as of STAT1- mediated transcriptional activity, making them promising targets to boost MHC I expression in immunosuppressed TMEs or in tumours with loss of function mutations in the IFN-γ pathway in combination with ICB
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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