1,720,954 research outputs found
Modulation of M1 and M2 muscarinic receptor subtypes following repeated organophosphate exposure in rats
No full textRepeated exposure to organophosphates has been shown to cause a decrease in muscarinic cholinergic receptors in the central and peripheral nervous system. The present study measured the modulation of M1 and M2 muscarinic receptor subtypes in rat brain areas during and following a 2-week daily exposure to the organophosphate disulfoton. The radioligands [3H]telenzepine and [3H]AFDX 384 were utilized to label M1 and M2 receptors, respectively. The study found comparable down-regulation in both [3H]telenzepine- and [3H]AFDX 384-labeled receptors in cortex, hippocampus, and striatum during exposure. Recovery of M2 subtype was slower than recovery of M1, especially in the hippocampus. The results suggest that M1 and M2 receptor subtypes may be similarly regulated in response to subchronic exposure to organophosphates, but that recovery of receptor subtypes to control levels may be governed by distinct factors
Modulation of muscarinic receptors and acetylcholinesterase activity in lymphocytes and in brain areas following repeated organophosphate exposure in rats
No full textRepeated exposures to organophosphorus (OP) insecticides has been shown to cause a decrease of cholinergic muscarinic receptors (mAChR) in brain and in peripheral tissues. These changes are believed to be involved in the development of tolerance to OP toxicity and may play a role in cognitive dysfunctions observed following repeated OP exposure. Recently, mAChRs identified in circulating lymphocytes have been shown to be modulated similarly to brain mAChRs following repeated OP exposure, suggesting that these peripheral cells may be useful as indicators of mAChR changes in the central nervous system. This study was designed to further investigate whether mAChRs on lymphocytes could serve as a biomarker for changes in brain mAChRs during prolonged OP exposure and during recovery from such exposure. Using the mAChR antagonist [3H]quinuclidinyl benzilate (QNB) to label mAChRs, we found that exposure to disulfoton for 14 days (2 mg/kg/day by gavage) caused a significant decrease (25-35%) in muscarinic receptors density in the cerebral cortex, hippocampus, and striatum, as well as in circulating lymphocytes. The decline of mAChR density in lymphocytes paralleled those observed in brain, particularly in cortex and hippocampus, during exposure to disulfoton; however, while brain mAChR levels recovered slowly after termination of exposure and remained significantly reduced 4 weeks after the last treatment, [3H]QNB binding in lymphocytes recovered rapidly within 1 week. Similarly, lymphocyte acetylcholinesterase (AChE) activity was significantly inhibited and correlated well with brain AChE activity during exposure, but the recovery was rapid relative to AChE activity in brain.(ABSTRACT TRUNCATED AT 250 WORDS
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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