1,721,054 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
In-depth characterization of porcine naive and memory CD4+ T cells
No full textBachelorarbeit - Veterinärmedizinische Universität Wien - 2023CD4+ T-Zellen sind ein wichtiger Bestandteil der adaptiven Immunantwort. Es ist allgemein anerkannt, dass sie sich nach Antigenexposition von naiven zu CD4+ T-Gedächtniszellen differenzieren. Im Jahr 1999 wurden zwei Hauptuntergruppen menschlicher T-Gedächtniszellen beschrieben: die Zentralen und die Effektor T-Gedächtniszellen. Jüngste Studien haben jedoch gezeigt, dass die Population der menschlichen CD4+ T-Zellen viel heterogener ist, was auf eine mögliche Existenz mehrerer Differenzierungsstadien hindeutet. Die Mehrfarben-Durchflusszytometrie, in der spezifische Marker für die T-Zell-Differenzierung kombiniert werden können, kann weitere Erkenntnisse zu diesem Thema liefern. Da das Schwein als vielversprechendes biomedizinisches Tiermodell beschrieben ist, sind weitere Studien über das porzine Immunsystem erforderlich. In vergangenen Studien wurden Parallelen zwischen humanen und porzinen Lymphozyten festgestellt, daher erwarteten wir für unsere Studie über porzine CD4+ T-Zellen auch eine hohe Heterogenität der Subpopulationen. Ziel dieser Studie war es, ein komplexes Mehrfarben Panel für die Durchflusszytometrie zur genaueren Charakterisierung der CD4+ naiven und T-Effektor/Gedächtnis-Zellsubsets vom Schwein zu entwickeln. Dazu wurden die Zelloberflächenmarker CD4, CD8α, CD27, CD28, CD45RA, CD45RC, CD62L, CD95, CCR7 und MHC-II untersucht. Für die Studie wurden periphere mononukleäre Blutzellen aus dem Blut von sechs Monate alten gesunden Tieren durch Gradientenzentrifugation isoliert. Die naiven und die T-Gedächtniszellen wurden anhand der Expression von CD8α/CD27 definiert - entsprechend der Literatur über Schweinezellen. In einem weiteren Schritt wurden die Zellen anhand der Expression von CCR7/CD45RA analysiert - einer Markerkombination, die für die menschlichen T-Zellen verwendet wird. Unsere Ergebnisse weisen auf das Vorhandensein vielfältiger Subpopulationen von naiven und CD4+-Effektor-/Gedächtnis-T-Lymphozyten hin. Neben CCR7+CD45RA+ Zellen innerhalb der CD4+CD8α-CD27+ naiven T-Zellen wurde eine Population von Zellen gefunden, die CD45RA herunterreguliert hatte. CD4+CD8α+CD27+ Zentrale T-Gedächtniszellen bestanden aus CCR7+CD45RA- und CCR7-CD45RA- Zellen, sowie einer kleineren Untergruppe mit einem CCR7+CD45RA+ Phänotyp. CD4+CD8α+CD27- Effektor T-Gedächtniszellen hatten hauptsächlich einen CCR7-CD45RA- Phänotyp, aber es wurden auch geringere Frequenzen von CCR7+CD45RA- oder CCR7-CD45RA+ Subpopulationen beobachtet. Letzter Phänotyp repräsentiert final differenzierte Effektor T-Gedächtniszellen. Die CD28 Expression war hoch in naiven und Zentralen T-Gedächtniszellen und nahm in Effektor T-Gedächtniszellen ab. Die Expression von CD62L hingegen nahm bereits in den Subpopulationen der Zentralen T-Gedächtniszellen ab und war in den verschiedenen Subpopulationen der Effektor T-Gedächtniszellen nicht vorhanden. Die Expression von CD95 wurde dagegen nur in den Subpopulationen der Zentralen T-Gedächtniszellen gemessen und MHC-II wurde ausschließlich im Differenzierungsstadium der Effektor T-Gedächtniszellen hochreguliert. Die Expression von CD45RC war dagegen sehr heterogen innerhalb der verschiedenen CD4+ Subpopulationen. Zusammenfassend heben diese Daten die große Variabilität der CD4+ naiven und T-Gedächtnis/Effektorzellen beim Schwein hervor, die uns die verschiedenen Übergangsstadien der T-Zell-Differenzierung beim Schwein erklären könnte.Bachelor thesis - University of Veterinary Medicine Vienna - 2023CD4+ T cells are an important component of the adaptive immune response. It is generally acknowledged that after antigen exposure they differentiate from naïve to memory CD4+ T cells. In 1999 two main subsets of human memory T lymphocytes were described, the central memory and effector memory T cells. However, recent studies showed that the human CD4+ T-cell population is much more heterogenous, hinting there may be more differentiation stages than formerly described. More insight into this topic can be provided by multi-color FCM, combining specific markers associated with T-cell differentiation. As swine is being considered as a potential biomedical animal model, further studies of its immune system are needed. Similarities between human and porcine lymphocytes have been observed, therefore for our study on porcine CD4+ T cells we also expected a high subset heterogeneity. The goal was to establish an applicable complex multi-color staining panel for better characterization of the porcine naive and effector/memory CD4+ T-cell subsets with cell surface markers CD4, CD8α, CD27, CD28, CD45RA, CD45RC, CD62L, CD95, CCR7, and MHC-II. For the study peripheral blood mononuclear cells were isolated from blood of six 6-months old healthy animals by gradient centrifugation. The expression of the markers mentioned above was analyzed by multi-color FCM. The naïve and memory subsets were defined by CD8α/CD27 expression – according to literature on porcine cells, and further analyzed by CCR7/CD45RA expression – a marker combination used for human T cells. Our results indicate the presence of various subpopulations of naïve and effector/memory CD4+ T lymphocytes. Besides CCR7+CD45RA+ cells within CD8α-CD27+ naive, a prominent subset of cells that downregulated CD45RA was observed. CD4+CD8α+CD27+ TCM consisted of CCR7+CD45RA-, CCR7-CD45RA-, as well as a minor subset with a CCR7+CD45RA+ phenotype. CD4+CD8α+CD27- TEM mainly had a CCR7-CD45RA- phenotype, but also CCR7+CD45RA- or CCR7-CD45RA+ subpopulations were observed. The latter representing TEMRA. CD28 expression was high in naïve and TCM subsets and declined in TEM and TEMRA defined stages. CD62L expression on the other hand declined already in TCM subpopulations and was absent in TEM and TEMRA subsets, while CD95 expression was only observed within TCM subsets and MHC-II was upregulated only towards the TEM stage. Expression of CD45RC showed a more heterogenous expression within the diverse CD4+ subsets. Together, this data highlights the high variability of porcine naïve and memory/effector CD4+ T cells which may cast light on diverse transitional stages of T-cell differentiation in the pig
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
Antiviral Properties of Carbon-Based Quantum Dots
No full textBachelor thesis - University of Veterinary Medicine Vienna - 2023Carbon quantum dots (CQDs) are small, carbon-based nanoparticles, valued for their excellent biocompatibility, chemical stability, and strong photoluminescence, with antibacterial, anticancer, and antiviral properties. CQDs can be easily synthesized via top-down (breaking down larger carbon structures, such as graphite) or bottom-up (formation from molecular precursors, such as citrate) methods. CQDs used in this study were synthesized via a bottom-up approach from citric acid.We performed cytotoxicity assays on these CQDs using (i) Sulforhodamine B (SRB) assay to examine effects on cell proliferation, and (ii) Annexin V flow cytometric analysis to examine the induction of apoptosis in primary mouse embryonic fibroblasts (pMEFs). Our results indicate a high biocompatibility of CQDs. Next, we investigated the antiviral properties of CQDs against murine cytomegalovirus (MCMV) using a plaque-forming unit (PFU) assay. Cells were pre-treated with CQDs (0.05 mg/mL and 0.005 mg/mL) for 24 hours and subsequently infected with MCMV. Viral plaques were counted under a microscope, and a significant decrease could be observed in CQD-treated samples in a dose-dependent manner. To better understand the antiviral effect, we isolated RNA from CQD-treated and untreated pMEFs. We performed RT-qPCR to quantify the expression of ISGs (e.g. Stat1, Stat2, Irf7, Prk etc.), Tnfa and Il-1b, which all are genes encoding proteins that are involved in the antiviral defence. All tested genes were upregulated in CQDs-treated samples in a dose-dependent manner. Our data indicate that CQDs produced from citric acid might be promising candidates for creating novel antiviral agents against CMV.Bachelorarbeit - Veterinärmedizinische Universität Wien - 2023Carbon quantum dots (CQDs) sind kleine, auf Kohlenstoff basierende Nanopartikel, die für ihre hervorragende Biokompatibilität, chemische Stabilität und starke Photolumineszenz geschätzt werden. Des weiteren besitzen sie antibakterielle, krebshemmende und antivirale Eigenschaften. CQDs können leicht durch „Top-Down-“ (Abbau größerer Kohlenstoffstrukturen, wie z. B. Graphit) oder „Bottom-Up“-Methoden (Bildung aus molekularen Vorläufern, wie z. B. Citrat) synthetisiert werden. Die in dieser Studie verwendeten CQDs wurden über einen Bottom-up-Ansatz aus Zitronensäure synthetisiert.Wir analysierten die Zytotoxizität dieser CQDs auf primäre murine Fibroblasten (pMEFs) mittels (i) Sulforhodamin B- (SRB-) Tests zur Untersuchung der Auswirkungen auf die Zellproliferation und (ii) Annexin V-Durchflusszytometrie zur Untersuchung der Induktion von Apoptose. Unsere Ergebnisse weisen auf eine hohe Biokompatibilität der CQDs hin. Als Nächstes untersuchten wir die antiviralen Eigenschaften von CQDs gegen das murine Cytomegalovirus (MCMV) mit Hilfe eines PFU-Assays (Bestimmung von Plaque-bildenden Einheiten). Die Zellen wurden 24 Stunden mit CQDs (0.05 mg/mL und 0.005 mg/mL) behandelt und anschließend mit MCMV infiziert. Die viralen Plaques wurden unter dem Mikroskop gezählt. Wir konnten in den mit CQD behandelten Zellen einen dosisabhängigen, signifikanten Rückgang der Anzahl viraler Plaques nachweisen. Um die antivirale Wirkung besser zu verstehen, isolierten wir RNA aus CQD-behandelten und unbehandelten pMEFs und quantifizierten die Expression von ausgewählten ISGs (z. B. Stat1, Stat2, Irf7 und Prk), Tnfa und Il-1b mittels RT-qPCR. Diese Gene kodieren alle für Proteine, die an der antiviralen Abwehr beteiligt sind. Wir konnten zeigen, dass alle getesteten Gene durch CQD-Behandlung dosisabhängig hochreguliert werden. Unsere Daten deuten darauf hin, dass aus Zitronensäure hergestellte CQDs vielversprechende Kandidaten für die Entwicklung neuer antiviraler Mittel gegen CMV sein könnten.Bachelor thesis - University of Veterinary Medicine Vienna - 2023Carbon quantum dots (CQDs) are small, carbon-based nanoparticles, valued for their excellent biocompatibility, chemical stability, and strong photoluminescence, with antibacterial, anticancer, and antiviral properties. CQDs can be easily synthesized via top-down (breaking down larger carbon structures, such as graphite) or bottom-up (formation from molecular precursors, such as citrate) methods. CQDs used in this study were synthesized via a bottom-up approach from citric acid.We performed cytotoxicity assays on these CQDs using (i) Sulforhodamine B (SRB) assay to examine effects on cell proliferation, and (ii) Annexin V flow cytometric analysis to examine the induction of apoptosis in primary mouse embryonic fibroblasts (pMEFs). Our results indicate a high biocompatibility of CQDs. Next, we investigated the antiviral properties of CQDs against murine cytomegalovirus (MCMV) using a plaque-forming unit (PFU) assay. Cells were pre-treated with CQDs (0.05 mg/mL and 0.005 mg/mL) for 24 hours and subsequently infected with MCMV. Viral plaques were counted under a microscope, and a significant decrease could be observed in CQD-treated samples in a dose-dependent manner. To better understand the antiviral effect, we isolated RNA from CQD-treated and untreated pMEFs. We performed RT-qPCR to quantify the expression of ISGs (e.g. Stat1, Stat2, Irf7, Prk etc.), Tnfa and Il-1b, which all are genes encoding proteins that are involved in the antiviral defence. All tested genes were upregulated in CQDs-treated samples in a dose-dependent manner. Our data indicate that CQDs produced from citric acid might be promising candidates for creating novel antiviral agents against CMV
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
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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