1,721,004 research outputs found
FMRP and its target RNAs: Fishing for the specificity
Full text linkLearning and memory difficulties observed in patients with fragile X syndrome, as well as in a mouse model for the syndrome, are partially due to impaired translational regulation of neuronal mRNAs encoding key molecules for the synaptic structure and function. There has been intense interest in characterizing the mRNAs that are regulated by the fragile X mental retardation protein (FMRP) in the neuronal cell. A large number of candidate FMRP-interacting mRNAs has been identified over the last few years and three models have been described so far to explain the specificity of these interactions. Here, we report our vision on how they could work in the same and/or in different pathways and suggest that the three mechanisms may not be mutually exclusive. © 2004 Lippincott Williams & Wilkins
mRNPs, polysomes or granules: FMRP in neuronal protein synthesis
Full text linkmRNA localization and regulated translation play central roles in neurite outgrowth and synaptic plasticity. A key molecule in these processes is the Fragile X mental retardation protein, FMRP, which is involved in the metabolism of neuronal mRNAs. Absence or mutation of FMRP leads to spine dysmorphogenesis and impairs synaptic plasticity. Studies that have mainly been performed on the mouse and Drosophila models for Fragile X Syndrome showed that FMRP is involved in translational regulation at synapses, but even 15 years after discovery of the FMR1 gene, the precise working mechanisms remain elusive.status: Publishe
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
Atrial natriuretic peptide effects on intracellular pH changes and ROS production in HEPG2 cells: Role of p38 MAPK and phospholipase D
Full text linkAims: The present study was performed to evaluate Atrial Natriuretic Peptide ( ANP) effects on intracellular pH, phospholipase D and ROS production and the possible relationship among them in HepG2 cells. Cancer extracellular microenvironment is more acidic than normal tissues and the activation of NHE- 1, the only system able to regulate pHi homeostasis in this condition, can represent an important event in cell proliferation and malignant transformation. Methods: The ANP effects on pHi were evaluated by fluorescence spectrometry. The effects on p38 MAPK and ROS production were evaluated by immunoblots and analysis of DCF- DA fluorescence, respectively. RT- PCR analysis and Western blotting were used to determine the ANP effect on mRNA NHE- 1 expression and protein levels. PLD- catalyzed conversion of phosphatidylcholine to phosphatydilethanol ( PetOH), in the presence of ethanol, was monitored by thin layer chromatography. Results: A significant pHi decrease was observed in ANP- treated HepG2 cells and this effect was paralleled by the enhancement of PLD activity and ROS production. The ANP effect on pHi was coupled to an increased p38 MAPK phosphorylation and a down- regulation of mRNA NHE- 1 expression and protein levels. Moreover, the relationship between PLD and ROS production was demonstrated by calphostin- c, a potent inhibitor of PLD. At the same time, all assessed ANP- effects were mediated by NPR- C receptors. Conclusion: Our results indicate that ANP recruits a signal pathway associated with p38 MAPK, NHE- 1 and PLD responsible for ROS production, suggesting a possible role for ANP as novel modulator of ROS generation in HepG2 cells. Copyright (C) 2005 S. Karger AG, Basel
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
- …
