1,721,022 research outputs found
Evaluation of fimS Orientation in Relationship to ompX and fimA Gene Expression in Different Sequence Types of Uropathogenic E. coli
No full textPandemic uropathogenic E. coli strain ST131 has been associated with multi-drug resistance and an increased likelihood of recurrent or persistent infections. Type-1-fimbriae have been implicated in ST131 biofilm formation, which can contribute to a persistent infection after antibiotic treatment. This suggests that type-1-fimbriae may contribute to the pandemic state of ST131. The type-1-fimbriae operon, beginning with fimA, is regulated by a promoter located on a region of DNA (fimS) that can be inverted by fim recombinases FimB and FimE. I hypothesized that ST131 strains upregulate fimA and have a higher percentage of the population with fimS in the On orientation compared to other sequence types. While three out of the four ST131 strains did have higher levels of fimA expression compared to the clinical isolate comparator (ST648), they did not have a higher percent of the population with fimS in the On orientation. These data suggest that the individual ST131 bacterium with fimS in the On orientation are upregulating fimA expression compared to the individual bacterium of the comparator strain. Decreases in outer membrane protein X (OmpX) have been implicated in increased type-1-fimbriae adhesion in E. coli lab strains. Therefore, I evaluated fimA expression in a lab parent strain and an ompX knockout strain. I also evaluated ompX expression in clinical isolates, including the ST131 strains, to compare changes in ompX expression with changes in fimA expression. While fimA expression increased in the ompX knockout strain, none of the ST131 strains showed a change in ompX expression compared to the clinical isolate comparator. The OmpC and OmpF protein production in the isolates from this study had previously been evaluated by doctoral candidate Corey Suelter. OmpC and OmpF form porins through which antibiotics can enter the cell. The ST131 strain with the greatest downregulation of OmpC had the highest percentage of fimS in the On orientation. To evaluate whether a decrease in either OmpC or OmpF impact fimA expression or the orientation of fimS, I evaluated fimA and the fimS orientation in ompC and ompF lab strain knockouts. The ompF knockout had the greatest increase in fimA expression and the percent of fimS in the On orientation. The ompC deletion clone showed an increase in the population with fimS in the On orientation while fimA expression in the population did not change. These data suggest that porins play a role in type-1-fimbriae production. Clinical isolates also contain plasmids with a variety of factors, including genes that encode antibiotic resistant enzymes such as ESBLs. The clinical isolates in this study, regardless of sequence type, with elevated levels of ESBL protein production had an increase in the percent of the population with fimS in the On orientation compared to the clinical isolate comparator. Taken together, these data suggest that ST131 clinical isolates differentially regulate type-1-fimbriae and that the regulation of this process is controlled by multiple mechanisms including OmpC protein production and perhaps unknown factors encoded on plasmids harboring ESBLs.ProQuest Traditional Publishing Optio
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
Cox, Rachel
No full textCertificate of Death, Arkansas State Board of Health, Bureau of Vital Statistics, for Rachel Cox, issued 27 November 1961.https://scholarlycommons.obu.edu/wiley_records/1175/thumbnail.jp
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