1,720,975 research outputs found
Protein expression in Fusobacterium nucleatum ATCC 10953 biofilm cells induced by an alkaline environment.
Get PDFFusobacterium nucleatum is a Gram negative anaerobic bacterium, frequently isolated from both healthy and diseased dental plaque and has been implicated in the aetiology of periodontal diseases. Studies have shown that this organism increases in number and proportion in diseased periodontal pockets suggesting that changes in the environment favour the growth of the organism. One of the physico-chemical changes that occurs in the diseased periodontal sulcus is an increased environmental pH, which may be as high as 8.5. In our laboratory, F. nucleatum subspecies polymorphum ATCC 10953 formed mono-culture biofilms at pH 8.2. The formation of biofilms in nature is a survival strategy for bacteria, often associated with altered physiology and increased virulence. The aim of this study was to investigate changes in F. nucleatum protein expression associated with these alkaline induced biofilms. A chemostat was used to produce F. nucleatum planktonic and biofilm cells grown at pH 7.4 and 8.2, respectively. The bacterial cells were separated into cell envelope and cytoplasmic fractions. The soluble proteins were extracted from each fraction and resolved by two-dimensional gel electrophoresis. Fifty five differentially expressed proteins were identified using mass spectrometry and database searching. These proteins were classified according to functional class, including metabolic, transport and stress proteins. One of the most interesting findings was the significant up-regulation of Fusobacterial Outer Membrane Protein A (FomA), a porin that is responsible for the coaggregation between F. nucleatum and periodontopathogens. It has been suggested that this protein may be a target for future vaccination against periodontal diseases. Other proteomic findings showed that transport proteins such as ATP binding cassette (ABC) transporter binding protein was down-regulated while tripartite ATP-independent (TRAP) transporter binding protein was enhanced in the alkaline environment. ABC transporters require ATP hydrolysis for solute transport. In contrast, TRAP transporter is ATP independent and co-transports protons into the cytoplasm, which may help maintain a neutral intracellular pH under alkaline conditions. The regulation of these transport proteins reflected the conservation of energy and maintenance of pH homeostasis in biofilm cells. In addition, F. nucleatum regulated key enzymes in energy-producing pathways. A combination of proteomic and other methods confirmed that biofilm cells increased their glucose uptake and storage as intracellular polyglucose in comparison to their planktonic counterparts. Furthermore, the increased energy requirement of these cells was associated with changes in metabolism resulting in both qualitative and quantitative shifts in acidic end-products. Bacterial biofilm formation can be triggered by adverse environmental conditions and the expression of stress proteins help to protect cellular functions. The stress proteins, GroEL and RecA, were up-regulated in biofilm cells and the expression of these proteins was verified using Western-blotting and quantitative real-time polymerase chain reaction techniques. In conclusion, this investigation successfully identified F. nucleatum proteins that were regulated in response to alkaline conditions, similar to those that are thought to exist in diseased periodontal pockets. The physiological adaptations observed, to the changed ecology, provide evidence at the molecular level supporting the key role of F. nucleatum in the establishment of mature dental plaque.Thesis (Ph.D.) -- University of Adelaide, School of Dentistry, 201
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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