1,720,956 research outputs found
Evaluation of high- and low-molecular weight fractions of sodium hyaluronate and an ionic complex as adjuvants for topical ophthalmic vehicles containing pilocarpine
No full textTwo low-molecular-weight fractions of sodium hyaluronate (Na-HA), denominated Hyalastin® and Hyalectin®, were investigated as potential adjuvants for ophthalmic vehicles containing pilocarpine nitrate (PiN). Tests were also performed on an ionic complex (HA/PiB) prepared from hyaluronic acid (derived from Hyalastin®) and pilocarpine base. The performance of the vehicles under study was verified by miosis and ocular retention tests carried out on albino rabbits, against a series of reference vehicles, three of which contained a high-molecular-weight fraction of Na-HA (Healon®). The group of 14 reference and test preparations exhibited Newtonian or pseudoplastic flow characteristics and encompassed a wide range of apparent viscosities (1 to 1054 mPa s). The results indicate that the HA/PiB salt and the high-MW Na-HA can significantly increase the bioavailability of pilocarpine with respect to reference vehicles of comparable viscosity: an effect that can be reasonably attributed to muco-adhesive effects. Conversely, in the present rabbit tests, the low-MW fractions of Na-HA performed poorly as adjuvants for the PiN solutions
Mucoadhesive liquid ophthalmic vehicles - Evaluation of macromolecular ionic complexes of pilocarpine
No full textPilocarpine (Pi), a widely used anti-glaucoma drug, is characterized by a very low bioavailability, due to poor corneal penetration and extensive precorneal loss. Purpose of the present study was the preparation and 'in vivo' evaluation of a series of liquid formulations containing salts (or ionic complexes) of Pi with soluble polyanionic polymers of natural, synthetic or semi-synthetic origin. It was speculated that since to some of the polymers have been attributed muco-adhesive properties, they might favour the preocular retention of the ionically bound drug, and enhance its bioavailability. The polymers submitted to investigation were a) hyaluronic acid (HA); b) poly-(galacturonic acid) (PGA); c) Mesoglycan (MG, a complex mixture of mucopolysaccharides); d) Carboxymethylchitin (CMCh) and e) two poly(acrylic acids) of different molecular weight (PAA1 and PAA2). Aqueous solutions of the Pi polymer salts, each containing 1.53% w/w Pi base (equivalent to 2.0% Pi nitrate) were tested for miotic activity in albino rabbits, using as reference an aqueous, 2% solution of Pi nitrate, either as such or viscosized with 1.5 and 5.0% poly(vinyl alcohol), (PVA). All polymeric solutions enhanced, in some cases to a statistically significant extent, the bioavailability of the drug with respect to the reference solutions. The relevance of viscosity effects, and of possible muco-adhesive phenomena to the bioavailability of Pi from the salt-vehicles are discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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