1,720,967 research outputs found
Mutation of the serine 15 phosphorylation site of human p53 reduces the ability of p53 to inhibit cell cycle progression.
No full textOverexpression of wild-type p53 prevents cells from entering the S phase of the cell cycle. The amino-terminal transactivation region of p53 is phosphorylated by several protein kinases, including DNA-PK, a nuclear serine/threonine protein kinase that in vitro requires DNA for activity. DNA-PK was recently shown to phosphorylate serines 15 and 37 of human p53 (Lees-Miller et al., 1992. Mol. Cell. Biol., 12, 5041-5049). To prevent phosphorylation at these sites, mutants were constructed that changed the codons for serine 15 or serine 37 to alanine codons. Expression of p53-Ala-37 in stably transformed T98G cells blocked progression of the cells into S phase as well as did the expression of wild-type p53. In contrast, p53-Ala-15 was partially defective in blocking cell cycle progression. Several cell clones transformed with the mutant p53-Ala-15 gene expressed normal levels of p53 mRNA but accumulated little or no detectable p53 protein. However, by using a transient expression system driven by a strong cytomegalovirus promoter, we showed that the inability of p53-Ala-15 to fully block cell cycle progression was not due to inadequate levels of expression or to a failure of the mutant protein to accumulate in the nucleus. These results suggest that phosphorylation of Ser-15 may affect p53 function
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
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
Defective Artemis causes mild telomere dysfunction
No full textThis article has been made available through the Brunel Open Access Publishing Fund.Background: Repair of DNA double strand breaks by non-homologous end joining (NHEJ) requires several proteins including Ku, DNA-PKcs, Artemis, XRCC4, Ligase IV and XLF. Two of these proteins, namely Ku and DNA-PKcs, are also involved in maintenance of telomeres, chromosome end-structures. In contrast, cells defective in Ligase IV and XRCC4 do not show changes in telomere length or function suggesting that these proteins are not involved in telomere maintenance. Since a mouse study indicated that defective Artemis may cause telomere dysfunction we investigated the effects of defective Artemis on telomere maintenance in human cells.
Results: We observed significantly elevated frequencies of telomeric fusions in two primary fibroblast cell lines established from Artemis defective patients relative to the control cell line. The frequencies of telomeric fusions increased after exposure of Artemis defective cells to ionizing radiation. Furthermore, we observed increased incidence of DNA damage at telomeres in Artemis defective cells that underwent more than 32 population doublings using the TIF (Telomere dysfunction Induced Foci) assay. We have also inhibited the expression levels of DNA-PKcs in Artemis defective cell lines by either using synthetic inhibitor (IC86621) or RNAi and observed their greater sensitivity to telomere dysfunction relative to control cells.
Conclusion: These results suggest that defective Artemis causes a mild telomere dysfunction phenotype in human cell lines.This article is available through the Brunel Open Access Publishing Fund. This study was supported by a grant from European Commission RISC-RAD contract FI6R-CT2003-50884
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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