1,721,030 research outputs found
Ca2+ permeability of human heteromeric nAChRs expressed by transfection in human cells
No full textThe Ca2+ permeability of the human heteromeric 34, 42 and 44 neuronal nicotinic acetylcholine receptors (nAChRs) was estimated by measuring the fractional Ca2+ current (Pf) flowing through the ligand-activated receptor-channels. Simultaneous recordings of transmembrane currents and fluorescence transients, using the whole-cell patch-clamp technique combined with fura-2 fluorescence microscopy, were performed in transiently transfected human cells. The human 42 nAChR showed a Pf value of 2.6%, while the human 34 nAChR showed a similar Pf value
of 2.7%. Conversely, 44 nAChR exhibited a Pf value (1.5%) significantly smaller than those of both 42 and 34 nAChRs. In test experiments performed in HEK 293 cells stably expressing rat GluR1AMPA receptor subunit,we repeated the determination of Pf, whose value (3.2%) has previously been reported by others using the same fluorescent dye; and we found a very similar Pf value (3.5%). In further test experiments, we found that Pf values of chick 34 (4.4%) and 44 (2.1%) matched those previously reported by us using confocal fluorescence microscopy. Thus, our findings
are consistent with those elsewhere reported even using different experimental procedures, giving a strong support to the following sequence of Ca2+ permeability: h-34 > h-42 > h-44
Fractional Ca2+ current through human neuronal alpha7 nicotinic acetylcholine receptors
No full textThe neuronal 7 nicotinic acetylcholine (ACh) receptor is believed to be a highly Ca2+ permeable ligand-gated receptor-channel.
However, the contribution of Ca2+ to cationic current generated by ACh has not yet been directly measured to date. Simultaneous
fluorescence and whole-cell current measurements using the Ca2+ indicator dye fura-2 were made inGH4C1pituitary cells stably expressing human 7 receptors and the fractional Ca2+ current (the proportion of whole-cell current carried by Ca2+; Pf ) was determined. We report that the Pf value was 11.4±1.3%. This value was significantly larger than Pf of human L248T7 receptor mutant (Pf = 6.3±1.0%) and of rat 7 receptor (Pf = 8.8±1.5%) both determined in transiently transfected GH4C1 cells. In our knowledge, the findings here reported indicate the human 7 receptors are the most Ca2+ conductive homomeric ligand-gated receptor-channels expressed in a heterologous cell system
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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