1,720,954 research outputs found
Fabrication of Model Plant Cell Wall Materials to Probe Gut Microbiota Use of Dietary Fiber
No full textThe cell wall provides a complex and rigid structure to the plant for support, protection from environmental factors, and transport. It is mainly composed of polysaccharides, proteins, and lignin. Arabinoxylan (AX), pectin (P), and cellulose (C) are the main components of cereal cell walls and are particularly concentrated in the bran portion of the grain. Cereal arabinoxylans create networks in plant cell walls in which other cell wall polysaccharides are imbedded forming complex matrices. These networks give an insolubility profile to plant cell wall. A previous study in our lab showed that soluble crosslinked arabinoxylan with relatively high residual ferulic acid from corn bran provided advantageous in vitro human fecal fermentation products and promoted butyrogenic gut bacteria. In the present work, arabinoxylan was isolated from corn bran with a mild sodium hydroxide concentration to keep most of its ferulic acid content. Highly ferulated corn bran arabinoxylan was crosslinked to create an insoluble network to mimic the cereal grain cell wall matrices. Firstly, arabinoxylan film (Cax-F), pectin film (P-F), the film produced by embedding pectin into arabinoxylan networks (CaxP-F), and cellulose embedding arabinoxylan matrices (CaxC-F), and embedding the mixture of cellulose and pectin into arabinoxylan networks (CaxCP-F) were fabricated into simulated plant cell wall materials. Water solubility of films in terms of monosaccharide content was examined and revealed that Cax-F was insoluble, and P-F was partially insoluble, and nanosized pectin and cellulose were partially entrapped inside the crosslinkedarabinoxylan matrices. In a further study, these films were used in an in vitro human fecal fermentation assay to understand how gut microbiota access and utilize the different simulated plant cell walls to highlight the role of each plant cell wall component during colonic fermentation. In vitro fecal samples, obtained from three healthy donors were used to ferment the films (Cax-F, P-F, CaxP-F, CaxC-F, and CaxCP-F) and controls (free form of cell wall components -Cax, P and C). The fabricated films that were compositionally similar to cell walls were fermented more slowly than the free polysaccharides (Cax and P). Besides, CaxP-F produced the highest short chain fatty acids (SCFA) amount among the films after 24 hour in vitrofecal fermentation. Regarding specific SCFA, butyrate molar ratio of all films was significantly higher than the free, soluble Cax and P. 16S rRNA gene sequencing explained the differences of the butyrate proportion derived from specific butyrogenic bacteria. Particularly, some bacteria, especially in a butyrogenic genera from Clostridium cluster XIVa, were increased in arabinoxylan films forms compared to the native free arabinoxylan polysaccharide. However, no changes were observed between P and P-F in terms of both end products (SCFA) and microbiota compositions. Moreover, CaxP-F promoted the butyrogenic bacteria in fecal samples compared with pectin alone, arabinoxylan alone, and the arabinoxylan film. Differences in matrix insolubility of the film, which was high for the covalently linked arabinoxylan films, but low for the non-covalent ionic-linked pectin film, appears to play an important role in targeting Clostridial bacterial groups. Overall, the cell wall-like films were useful to understand which bacteria degrade them related to their physical form and location of the fiber polymers. This study showed how fabricated model plant cell wall films influence specificity and competitiveness of some gut bacteria and suggest that fabricated materials using natural fibers might be used for targeted support of certain gut bacteria and bacterial groups
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
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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