1,720,996 research outputs found
MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORSXVI (x) - Synthesis qnd cholinergic activity ol 2- or 5-alkyl or 5-phenyl--4-methyl-3-oxo-1 -dimethylaminomethylcy clopentane methiodide.
No full textIn order to study the cholinergic receptor through affinitychromatography, some derivatives ol deoxamuscarone (1 a) incorporating alkyl and phenyl substituents at the positions 2 and 5 were synthesizedas model compounds. However, the sharp drop in activity and the lack of discrimination between nicotinic and muicarinic receptors exhibited by thecompounds discourage their further development as affinity reagent
MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORSXI - Synthesis and biological evaluation of isomuscarine and itsisomers
No full textThe synthesis of isomuscarine (lI c) and ol its threeisomers is described. Their structure were establisked on the basis olN.M.R. and I.R. data.unlike the dioxolane (l), lrom which they are lormally derived bysubstituting the oxygen in position 3 by a CHOH group, the isomuscarinesare completely devoid of cholinergic activity. This result is explained bythe impossibility ol the corresponding receptor site of accepting a grouplarger than the ether oxygen. Interactions ol the onium and C-7 methylgroups are assumed to be the driving lorces for binding with the muscarinicreceptor while a dipole-dipole interaction for oxygenated functions is propose
Affinity and efficacy correlate with chemical structuremore than potency does in a series of pentatomic cyclicmuscarinic agonists
No full text1 The efficacy and affinity of nine pentatomic cyclic muscarinic agonists were determined on theguinea-pig ileum, according to the method of Furchgott & Bursztyn {1967). 2 Tbe efficacy and affinity of these agonists are affected differently by structural modifications.3 Our results suggest that a strong dipole oriented in the same direction as that of the hydroxy groupof muscarine, or the presence of a polarizable atom in the same position, are important for efficac
MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORS
No full textSeveral ethers and acetylderivatives of deoxamuscorine(l) and its isomers have been synthesized and tested to eyaluate the volumetricrequirements of the site interacting with the hydroxyl moiety ol the agonist(muscarinic subsite)
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
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