1,720,998 research outputs found
N-homolupinanoyl and N-(omega-lupinylthio)alkanoyl derivatives of some tricyclic systems as ligands for muscarinic M1 and M2 receptor subtypes
No full textA set of N-homolupinanoyl- and N-(omega-lupinylthio)alkanoyl derivatives of tricyclic systems (as phenothiazine, iminodibenzyl and dihydropyridobenzodiazepinone) has been prepared and tested for affinity for rat muscarinic M(1) and M(2) receptor subtypes labeled with [3H]pirenzepine and [3H]AF-DX 384. Good affinity for both M(1) and M(2) subtypes was displayed by most compounds, often with nanomolar K(i) values, which for lupinylthiopropionyl- and lupinylthiobutyryl-phenothiazines (13-16) were comparable to those of pirenzepine and methoctramine, respectively. However, only moderate selectivity for one or the other subtype was seen
Epimerization of Lupinine to Epilupinine and viceversa. Reexamination of the Structures of Lupinal and Epilupinal
No full textAlthough the epimerization of lupinine (I) has been largely investigated, a previously not obsd. compd. of formula C10H17NO was now isolated from the mixt. of alkaloids that remains after the sepn. of epilupinine (II). It is insol. in dry Et2O but sol. in EtOH, from which it is recovered as an Et2O-sol. oil that slowly returns to the Et2O-insol. solid form. For these characteristics and based on GC/MS, 1H-NMR, and IR data, it is considered as the inner salt III of the common enolic form IV of lupinal and epilupinal, with which it is in equil. when standing in soln. The oily form, but not the solid one, is able to improve the conversion of I to II, establishing the role of the aldehydes in the epimerization process. It was obsd. that also II can be converted to I. Finally, the solid lupinal described by Zaboev should be considered as being identical to the now isolated inner salt III, while the oily epilupinal of Wicky and Schumann is, indeed, a mixt. of epilupinal with a minor amt. of lupinal, which, on standing, is converted to the inner salt III of the common enolic form IV
Synthesis and biological investigations of 2-(tetrahydropyran-2'-yl) and 2-(tetrahydrofuran-2'-yl)benzimidazoles
No full textA set of benzimidazole derivatives bearing on position 2 a tetrahydropyranyl or tetrahydrofuranyl residue was prepared and tested for antitumoral, anti HIV-1 and other pharmacological activities. While the anti-HIV activity was completely lacking, moderate antitumoral activity was found in a few compounds; particularly the 5,6-dichloro-2-(tetrahydropyran-2-yl)-benzimidazole (8) was able to inhibit the growth of 19 cell lines of humane tumors at near micromolar concentration. On the other hand compounds 4, 6-8 and 10 exhibited significant tracheal relaxant activity in vitro at concentration 3-10 micrograms/ml, thus resulting superior to theophylline and comparable to amrinone
Quinolizidinyl derivatives of 5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepin-6-one as ligands for muscarinic receptors
No full textQuinolizidinyl derivatives of the tricyclic systems characterizing pirenzepine and nuvenzepine, were prepared and tested as ligands for muscarinic M1, M2 and M3 receptors; 5,11-dihydro-11-[(S-lupinyl)-thioacetyl]-6H-pyrido[2,3-b] [1,4]benzodiazepin-6-one exhibited IC50 = 10 nM for M1 and 760 nM for both M2 and M3 subtypes. During the synthesis some interesting side compounds were isolated and characterized
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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