1,721,033 research outputs found
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
Microencapsulated environmental regulators to promote regeneration of the injured central nervous system
No full textIntroduction
The recent advances in regenerative medicine have led to the development of novel experimental therapies, at both the cellular and molecular levels, which aim at reversing the devastating consequences of acute spinal cord injury [1-2]. Several bioactive molecules able to promote regeneration of the injured nervous system show therapeutic potential only when delivered in a controlled and sustained fashion, via appropriate microcarriers. The aim of this work was to evaluate the suitability of poly(lactic-co-glycolic) acid (PLGA)-based microspheres (MS) as a means to deliver therapeutic amounts of either neurotrophic factors (for axonal protection), or inhibitors of bone morphogenetic proteins (for inhibition of the glial scar), following acute spinal cord injury in mice. Several MS formulations were prepared, in order to achieve proper release kinetics of the selected molecule(s), and the effect of the encapsulation technique on the structure and stability of the loaded molecule was assessed. The encapsulation of environmental regulators (ERs) in bioresorbable PLGA-based MS might be a promising approach to promote the regeneration of the injured nervous system.
Materials and Methods
Microsphere synthesis: PLGA-based MS were synthesized by means of a double emulsion/solvent evaporation technique (water/oil/water), as previously described [3]. The ER (e.g., recombinant mouse chordin) was loaded in the presence of bovine serum albumin (BSA) as stabilizing molecule, and MS were synthesized starting from different PLGA concentrations.
Microsphere characterization: The size distribution of MS was evaluated through dynamic laser light scattering, whereas MS morphology was assessed through scanning electron microscopy (SEM). The encapsulation efficiency was evaluated by UV spectrophotometry.
Release study: In vitro release of the ER was monitored in PBS at 37°C with gentle shaking, over a period ranging from 72 hours to 30 days, depending on the given MS formulation tested. In order to assess any effects of the presence of BSA on the ER release kinetics, both the total amount of protein (BSA+ER) released at selected time points and the released amount of ER were measured, by UV spectrophotometry (with a BCA-assay protein kit) and ER-specific ELISA assays respectively.
Protein/ER stability and bioactivity: The effect of the encapsulation technique on the structure of the loaded molecule(s) was assessed through sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectrofocalization (IEF), performed at selected time points along the sustained release. Specific bioassays, to assess the biological activity of the released ER, are currently in progress.
Results and Discussion
The average MS size was found to be significantly affected by the PLGA amount initially dissolved in the organic solvent used to prepare the double emulsion, with lower diameters attained for lower PLGA concentrations. As expected, release kinetics was greatly dependent on the mean MS size. Indeed, for the MS formulations tested, it was possible to modulate the time length of the sustained release of the ER from 3-4 days (for an average MS size of 15 μm, attained for a 10% w/v PLGA concentration) to 35 days (average MS size of 30 μm, attained for a 20% w/v PLGA concentration). The encapsulation efficiency was about 80-90% for all the MS formulations tested. The structural integrity of both BSA and ER was not affected by the encapsulation technique used, as demonstrated by the results of SDS-PAGE and IEF. However, the released fraction of ER as measured by the ELISA assays was found to be significantly lower than the amount expected from the total release study (BSA+ER). Along with in vitro bioactivity assays, specific release studies to understand this discrepancy between the total release of BSA and ER and the release of the only ER are currently being performed.
Conclusions
ER-loaded PLGA-based MS, possessing different mean diameters, were synthesized by a double emulsion/solvent evaporation technique. This technique yielded MS batches with a small size distribution and a high encapsulation efficiency, and preserved the structural integrity of the loaded molecules. The release kinetics could be tuned by varying the mean MS diameters. Based on these results, PLGA-based MS show potential for the local delivery of ERs to the injured nervous system. However, the suitability of the proposed MS to this purpose will be proved only following in vitro and in vivo bioactivity assays, scheduled in the next future
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
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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