1,720,966 research outputs found
Pharmacokinetics of Fluconazole in Normal Volunteers
No full textThe pharmacokinetic profile of fluconazole, after 100 mg i.v. infusion or oral administration of a single 50 mg or 150 mg dose, was investigated in 18 healthy volunteers. At a dose of 100 mg i.v., the half-life (t( 1/2 β)) was 29.73 ± 8.05h. The mean residence time in the plasma was 27.56 ± 5.98 h. The post-distributive volume V(β) = 52.16 ± 9.83 l, approximating that of total bodywater. Renal excretion accounted for 61.64 ± 8.80% of the drug elimination after 48 h, with renal clearance Cl(r) = 12.91 ± 2.83 ml/min. Plasma clearance (Cl(r)) was 21.03 ± 5.07 ml/min. At oral doses of 50 and 150 mg the distribution and elimination of fluconazole resembled that following i.v. infusion. The peak levels in plasma at 2.5 h were 0.93 ± 0.13 and 2.69 ± 0.43 μg/ml, respectively. The large distribution volume, the long half-life and mean residence times, combined with a rapid absorption after oral administration, suggest that fluconazole will be effective at a wide range of body sites
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
A linear model for the pharmacokinetics of azithromycin in healthy volunteers
No full textThe pharmacokinetic profile of azithromycin, after oral ingestion of 500 mg, was determined in 10 healthy volunteers. Statistical and biochemical reason seemed to indicate a zero-order absorption of the drug. The disposition of azithromycin was described by a two-compartment model (plasma compartment and extravascular compartment) with elimination from the plasma compartment. The absorption process ends abruptly after a time T = 2.3 ± 0.49 h, from the administration. The transfer rate constant from the plasma compartment to the extravascular compartment (k12 = 0.12 ± 0.04 h-1) and the mean residence time of the drug in the extravascular compartment (MRT2 = 43.53 ± 13.80 h) indicate a rapid and extensive distribution of azithromycin from the serum into the extravascular fluids. The results confirmed the efficacy of a single daily dose of 500 mg per os for clinical use
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
Activity of ceftibuten, cefaclor, azithromycin, clarithromycin, erythromycin and telithromycin against Streptococcus pyogenes clinical isolates with different genotypes and phenotypes
No full textBackground: The growing number of macrolide-resistant strains of Streptococcus pyogenes represents an increasing worldwide problem. Macrolide resistance in S. pyogenes is mediated by several different genes, which determine different levels of resistance to macrolides, lincosamides and streptogramin B (MLS). Methods:This study compared the in vitro antimicrobial activity of azithromycin, clarithromycin, erythromycin, ceftibuten, cefaclor, and telithromycin against 287 strains of S. pyogenes by the broth microdilution method. All strains were characterized both phenotypically and genotypically for erythromycin resistance and most of them have been M-typed by means of PCR. Results: Ceftibuten and cefaclor showed the best antimicrobial activity, while MIC values for telithromycin were higher against constitutively MLS (cMLS)-resistant strains rather than against the other phenotypes. Conclusion: Oral cephalosporins retain the best activity against S. pyogenes; showing good activity except for cMLS-resistant strains, telithromycin is a valid alternative to these antimicrobials
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