1,720,962 research outputs found
Evaluatie van bacteriële virussen en afgeleide producten voor de controle van Staphylococcus aureus
No full textStaphylococcus aureus is a major problem in health care settings and livestock breeding across the world. This opportunistic bacterium is responsible for various infections of the skin, systemic infections and sepsis. Moreover, its increasing antibiotic resistance and ability to form biofilms, sessile communities of bacterial cells embedded in an extracellular matrix, necessitates alternatives for classical treatment and therefore drives the renewed interest in (bacterio)phages. However, the therapeutic use of these bacterial viruses (phage therapy) remains underdeveloped. Two phages infecting S. aureus, Romulus and Remus, were isolated from sewage of the UZ Leuven Campus Gasthuisberg (Belgium). Phage ISP, obtained from the Eliava Institute of Bacteriophage, Microbiology and Virology in Tbilisi (Georgia), was already available. The newly isolated phages as well as phage ISP are myoviruses, known by their long contractile tail, and taxonomic members of the genus Twortlikevirus. Romulus and Remus are very closely related to each other and to S. aureus phage SA11, but display no more than 60% DNA homology with other staphylococcal myoviruses. Therefore, three species within the genus Twortlikevirus, represented by phages K, Remus and Twort, were proposed based on phenotypical properties and genome organization.A thorough microbiological, genomic and proteomic characterization was carried out for the three phages. Host range screening of a large batch of S. aureus isolates revealed activity of ISP, Romulus and Remus against 87%, 69% and 68% of the isolates, including relevant MRSA isolates. Furthermore, where all human S. aureus isolates were sensitive to ISP infection, Romulus and Remus infected 28 and 30 out of 36 S. aureus isolates of patients, respectively. In contrast to the 22 phage propagation strains infected by ISP, only nineteen and eighteen of the 31 phage propagation strains were sensitive to Romulus and Remus, respectively. Hence, the host range of Romulus and Remus is relatively narrow compared to phage ISP. Considering their close relatedness, the differences in host range and efficiency of plating between Romulus and Remus are remarkable. Furthermore, S. haemolyticus and S. epidermidis isolates appeared to be insensitive to the three phages. The adsorption to and subsequent infection of S. aureus in liquid culture was studied. The adsorption experiments revealed similar adsorption characteristics for ISP, Romulus and Remus, whereas the in vitro infection patterns of Romulus and Remus showed a faster killing of liquid S. aureus cultures compared to ISP. In a proof-of-concept experiment, phage Remus seemed to be most promising in controlling a S. aureus PS47 biofilm. To determine optimal storage and application conditions, the survival of ISP, Romulus and Remus at different temperatures and pH values was tested. Phages ISP, Romulus as well as Remus were stable within a pH range of 5 to 9. Consequently, oral administration of the phages would require protection from the acidic environment of the stomach. The three phages appeared to be stable at 4°C and 16°C. Whereas ISP was stable at 37°C and 42°C as well, the Romulus and Remus titers drop with approximately one logarithmic unit at 37°C and at 42°C the logarithmic decrease was considerable. This should be taken into account in case of systemic use. Specifically for phage ISP, the frequency of bacterial mutations conferring resistance was determined and an alternative purification method using CIM® Disk Monolithic Columns was optimized. Furthermore, subcutaneous as well as nasal and oral ISP administration to rabbits was demonstrated to cause no adverse effects.ISP, Romulus and Remus encode 215, 180 and 189 gene products on their 138,339 bp, 131,333 bp and 134,643 bp genomes, respectively. Promoters, terminators, tRNAs and protein functions were predicted. No toxic, lysogeny- or virulence-associated proteins were observed. Structural proteome analysis identified 22 and nineteen virion proteins for ISP and Remus, respectively. Exploration of phage-encoded proteins represented an intriguing sidestep of this research. Although several candidates were indicated, no ISP-encoded exopolysaccharide depolymerase was detected. On the other hand, a receptor-binding protein of phage ISP, possibly targeting the cell wall teichoic acids in the S. aureus envelope, was identified. Moreover, this receptor-binding protein, Gp40, appeared to be the short tail fiber of phage ISP. Another ISP-encoded structural protein, Gp38, was localized near the baseplate, but no function could be suggested. The microbiological and molecular characterization of ISP, Romulus and Remus supports their application for therapeutic purposes, although some of their characteristics are not ideal for specific situations in phage therapy. In addition, fundamental insight in taxonomy, genome organization and the distribution of group I introns in twortlikeviruses was obtained. Based on bioinformatic analysis and immunogold localization experiments, four components of the ISP virion (Gp18, Gp19, Gp33 and Gp40) were indicated in a preliminary Twortlikevirus tail model.status: Publishe
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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