1,720,963 research outputs found
Bowman-Birk protease inhibitor activates DNA-dependent protein kinase and reduces formation of radiation-induced dicentric chromosomes
No full textPurpose: To test a stimulatory effect of the radioprotector Bowman Birk protease inhibitor (BBI) upon DNA repair processes. Materials and methods: An effect of BBI upon DNA repair was investigated by quantification of radiation-induced dicentric chromosomes. Sensitivity to ionizing radiation was determined by clonogenic survival assay. Quantification of activity of the DNA-dependent kinase was performed by immunoprecipitation and phosphorylation of a TP53-derived peptide. Results: The formation of radiation-induced dicentric chromosomes was reduced significantly after pretreatment of cells with BBI. By using a cell line with an inducible expression of a mutated TP53, it was shown that the BBI-mediated reduction of dicentric chromosome formation depended on the presence of wild-type TP53. To get further insights into the molecular mode of action of BBI, activity of the DNA-dependent protein kinase (DNA-PK) was quantified. BBI treatment resulted in a stimulation of basal (DNA-PK) activity. In SCID mouse fibroblasts deficient in DNA-PK activity, BBI failed to reduce the amount of radiation-induced dicentric chromosomes and the radioprotective effect was absent. Likewise, cells expressing mt.TP53 did not show radioprotection by BBI. Conclusions : It was observed that BBI exerts its radioprotective effect by a reduction of incorrect DNA repair, resulting in a reduced amount of dicentric chromosomes. This effect on the fidelity of DNA repair is TP53 dependent and correlated with induction of DNA-PK activity
Cellular analyses on human gingiva fibroblasts into the biological efficacy of bioactive laser light
No full textDas Ziel der vorliegenden Doktorarbeit war es, die Wirksamkeit niederenergetischen infraroten Laserlichtes auf das Proliferations- und Regenerationsverhalten von humanen Gingiva-Fibroblasten zu analysieren.
In einer ersten experimentellen Serie sollte hierbei eine Dosisfindungsstudie hinsichtlich der zu applizierenden Intensität (1-5 mW bei 630 nm) mit Hilfe klonaler Testsysteme durchgeführt werden.
In Rahmen dieser Untersuchungen sollten auf statistischer Basis Aussagen darüber ermöglicht werden, inwiefern das vorgeschlagene infrarote Laserlicht tatsächlich eine Beeinflussung von Gingivazellen im Sinne einer Aktivierung von Zellproliferationsprozessen induziert.
In einem zweiten Ansatz sollte überprüft werden, wie Zytokine und hier insbesondere die Interleukine, alleine und in Kombination mit der Bestrahlung auf die Gingiva-Fibroblasten wirken. Diese Experimente sind insbesondere unter dem Aspekt zu sehen, dass eine potentiell denkbare "Ausverdünnung" des Regenerationspools der Gingiva-Vorläuferfibroblasten durch die Zytokine verstärkt werden und somit potentiell negative Langzeitfolgen der Zytokine auf die Gingiva durch Laserbestrahlung vermieden werden könnte.
Für die Findung der optimalen Zytokin-Konzentrationen wurden 0,1, 1, 10 und 25 ng/ml eingesetzt. Die optimale beste Hemmungs-Konzentration der Zytokine wurde unter alleiniger Behandlung und in Kombination mit Laserlicht in die Experimente eingebracht.
Werden hierbei Daten erhoben, die auf eine kombinatorische Wirkung und Nutzung in der Mundpflege hinweisen, sind diese Ergebnisse Gegenstand eines auszuarbeitenden Patentes.The aim of the doctoral dissertation was to analyze the effect of low-energetic infra-red laser light on the proliferating and regenerating behavior of human gingival fibroblasts.
In a first experimental series with the help of clonal test systems a study was made defining the finding of appropriate doses of the intensity which is to apply (1-5 mW at 630nn). In the frame of these analyses on a statistic basis statements were made possible about the proposed infra-red laser light really inducing an influence on gingival cells in the sense of an activation of cell proliferating processes.
In a second step the aim was to check in what measure cytocins and especially interleukins by their own and in combination with radiotherapy have an effect on gingival fibroblasts. These experiments have to be viewed especially under the aspect that a potential and possible “dilution” of the regenerating pool of the gingival pre-fibroblasts can be strengthened with the help of cycotins. Thereby potential negative and long-term effects of the cycotins on the gingiva via infra-red radiotherapy could be avoided.
In order to find optimal cycotin concentration 0,1, 1, 10 and 25 ng/ml were applied. The optinal and best obstructing concentration of the cycotins was brought into the experiments by applying them on their own and in combination with laser light.
If in this case data are defined that indicate on a combinatory effect and use in the oral hygiene, these results are target of a patent that needs to be developed
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
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
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
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