1,720,963 research outputs found
Labelling of A1 and A3 adenosine receptors with the new selective A1 agonist 2'-Me-CCPA
No full textBrain is rich of adenosine receptors. Radiolabelled adenosine receptor agonists such as [3H]N6-cyclohexyladenosine ([3H]CHA) and [3H]phenylisopropyladenosine were largely used for labelling adenosine A1 receptor sites. Unfortunately, these radioligands label both A1 and A3 receptors. Hence, the majority of studies performed so far did not discriminate between these adenosine receptor subtypes. Some studies have introduced non labelled adenosine A3 receptor antagonists to discriminate between the 2 sites, whereas no highly selective agonists allowing such a discrimination are available. In this study we propose the use of 2'-C-methyl-2-chloro-N6-cyclopentyladenosine (2'-Me-CCPA) to discriminate A1 and A3 adenosine receptors in sections of rat cerebral cortex and hippocampus. This compound synthesized by us proved to be a potent and selective agonist at A1 receptors active in the nanomolar range. It has affinity for A2 and A3 receptors in the micromolar range only.
In sections of rat frontal and occipital cortex and hippocampus exposed to [3H]CHA in the presence or in the absence of different adenosine receptor agonists, [3H]CHA was bound with high affinity, in a manner consistent with the labelling of adenosine receptors. The highest density of binding sites was found in the occipital cortex, followed by the frontal cortex and hippocampus. Concentrations of 2'-Me-CCPA between 0.1 and 10 nM labelled almost all adenosine A1 receptors. The compound reduced by about 70%, 50% and 25% [3H]CHA binding to frontal cortex, occipital cortex and hippocampus, respectively.
These findings indicate that in the frontal cortex the majority of [3H]CHA binding belongs to the A1 receptor subtype, in the occipital cortex A1 and A3 receptors are expressed in similar percentages, whereas in the hippocampus the A3 receptor predominates. Based on these results we suggest that 2'-Me-CCPA may represent an adenosine receptor agonist suitable for discriminating A1 and A3 receptors
Farmacocinetica della flumequina nella capra. Dati preliminari
No full textFlumequine kinetics, administered intravenously (i.v.) and intramuscularly (i.m.) at 20 mg.kg-1, was investigated in 6 healthy goats, and the kinetic parameters obtained related to minimal inhibitory concentrations (MIC90) reported in literature. After i.v. injection, flumequine distributed rapidly (t1/2α = 0.87 ± 0.15 h) but was eliminated slowly (t1/2β = 7.12 ± 1.27 h). After i.m. administration, peak serum level (Cmax= 7.40±0.5 μg.mL-1) and bioavailability (>90%) of the drug indicate that flumequine could have a good efficacy against systemic infections sustained by susceptible microorganisms
Cinetica e biodisponibilita' del naproxene nel cavallo sportivo
No full textThe kinetics of naproxen (NSAIDs), orally (OS) administered at the daily dose of 10 mg.kg-1 repeated for 5 consecutive days, was investigated in 5 healthy race-horses. The kinetics was described by a monocompartimental model. The drug showed an elimination half-life of 6.48 hours (T1/2el); the peak concentration (mean Cmax = 38.62 mcg.ml-1) was attained in about 3.25 hours (mean Tmax); the clearance (mean value) was 0.020 L.h-1.kg-1. The bioavailability (F = 89.31%) was calculated by comparing the oral AUC values and the intravenous AUC values (data reported in a previous paper)
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
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