1,720,953 research outputs found
Calcium involvement in the mechanism of action of Limonene as a penetration enhancer for topical/transdermal drug products
Get PDFThe addition of chemical permeation enhancers (CPE) to a topical dermatological formulation is the prevalent approach to improve permeability of active pharmaceutical ingredients (API) across the stratum corneum. Terpenes have been used as CPEs for a long time since they are safe and non-irritating. Limonene is one such terpene majorly found in essential oils extracted from citrus fruits and many varieties of cannabis. Studies performed using Limonene as PE show that Limonene was able to increase the flux of the drug by many folds. Limonene acts as an agonist to transient receptor potential ankyrin 1 (TRPA1) receptor – the activity of which is highly Ca2+ dependent. Since, calcium is found in the entire epidermis, the purpose of this study was to evaluate whether the above-mentioned properties of Limonene are related to its penetration enhancing effects. The aim of this study was to investigate whether the permeation enhancers R-Limonene (R-L) & S-Limonene (S-L) might act by decreasing the extracellular Ca2+ concentration that it is responsible for the tight cell-cell adhesion in the stratum corneum. This was followed by testing the suitability of microdialysis technique for DPH and DTZ through recovery and retrodialysis (loss) experiments. Finally, in vivo experiments were performed on a rabbit model. A randomized, crossover, single-dose, four treatment study design was chosen so that each rabbit would receive the test and reference formulation. The four gel combinations – control (5% DPH); test (5% DPH + 1%R-L or 1% S-L); control + DTZ (5% DPH + DTZ); test + DTZ (5% DPH + 1% R-L or 5% DTZ) were applied to the rabbit’s dorsal surface on the same day and dermal concentration profiles of DPH were assessed using microdialysis. The pharmacokinetic parameters such as Cmax and AUCinf were estimated using Phoenix WinNonlin Non Compartmental Analysis and studied for comparison between different formulations. The gels containing R-L or S-L showed slightly higher dermal exposure of DPH compared to the control gel. Whereas the dermal exposure from the gel containing DTZ was not different from the control gel. The results support the hypothesis that Limonene inhibition of Ca+2 activity in the skin might contribute to its penetration enhancing effect, although more in-vivo experiments are necessary to further prove this hypothesis. The first step was to find the optimal concentration of limonene that enhances the penetration of a model drug, diphenhydramine (DPH) from topical dermatological gels. Seven gels containing 5% DPH were prepared with 0 (control) and three increasing concentrations of R-L or S-L (1.00, 1.75, and 2.50 %) using simple dispersion method. An in-vitro release study across regenerated cellulose membrane using Franz cell apparatus was conducted to evaluate any possible physical interaction by assessing release parameters like flux and cumulative amount permeated. Then, an ex vivo study using porcine ear skin was performed to select the optimal percentage of R-L and S-L. The 1.00% R-L and 1.00% S-L increased permeability of DPH by 82.37% and 111.51%, respectively compared to control formulation, whereas higher percentages were not significantly different from control gel. Then, the calcium channel blocker diltiazem (DTZ) was added to the selected formulations to evaluate whether it counteracts the penetration enhancing effects of R-L or S-L. These formulations were tested again in-vitro on regenerated cellulose membrane to evaluate physical interaction before proceeding to the in vivo studies. All gels were tested for consistency, transparency, and uniformity of content. Samples were analyzed with a bioanalytical method specifically developed and validated for DPH/DTZ combination
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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