1,720,957 research outputs found
Characterization of Adaptive Quorum Sensing in Pseudomonas aeruginosa
Get PDFPseudomonas aeruginosa is an opportunistic pathogen that is highly antibiotic resistant and causes tens of thousands of infections each year. It persists in hospitals by forming biofilms on medical equipment like ventilators and catheters, making it difficult to eradicate. Biofilm formation, among other virulence factors of P. aeruginosa, is regulated through quorum sensing, a mechanism of bacterial communication. Quorum sensing is primarily coordinated through LuxI-R type systems comprised of an autoinducer synthase and receptor, respectively. Canonically, the first system to be expressed is LasI-R, and LasR upregulates the second arm of the quorum sensing network, the RhlI-R system. Research on clinical strains of P. aeruginosa has shown that there is a high frequency of LasR-inactivating mutations, in both chronic and acute infection strains, resulting in complete loss of LasR signaling. However, quorum sensing is maintained in these strains through the RhlI-R system. This dissertation characterizes the different ways in which the RhlR transcription factor is expressed, activated, and stabilized independent of LasR regulation to provide insights on virulence gene regulation through adaptive quorum sensing in P. aeruginosa
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
Understanding the Link Between Chemotaxis and Biofilm Dispersion Systems in Pseudomonas Aeruginosa
No full textThe opportunistic pathogen P. aeruginosa forms biofilms during chronic lung infections in cystic fibrosis patients, contributing to morbidity and mortality. Not only are biofilms antibiotic resistant but dispersal may release pathogenic bacteria throughout the body. Previous research discovered a novel interaction between DipA, a phosphodiesterase that promotes biofilm dispersal, and ParP, which localizes chemosensory clusters and has AIF (array integration and formation) domain homology to CheA and CheW of the chemotaxis system. This research was focused on further deciphering the role of ParP’s AIF domain in mediating the interactions between DipA and CheA by using a bacterial two hybrid system. We also explored the functional redundancy of ParP and CheW AIF domains with swimming assays and found that ParP’s AIF domain was unable to restore swimming motility in a ∆cheW mutant strain. This research may provide new targets for safe biofilm dispersal within the lungs of cystic fibrosis patients.2020-06-1
Understanding the Link Between Chemotaxis and Biofilm Dispersion Systems in Pseudomonas Aeruginosa
No full textThe opportunistic pathogen P. aeruginosa forms biofilms during chronic lung infections in cystic fibrosis patients, contributing to morbidity and mortality. Not only are biofilms antibiotic resistant but dispersal may release pathogenic bacteria throughout the body. Previous research discovered a novel interaction between DipA, a phosphodiesterase that promotes biofilm dispersal, and ParP, which localizes chemosensory clusters and has AIF (array integration and formation) domain homology to CheA and CheW of the chemotaxis system. This research was focused on further deciphering the role of ParP’s AIF domain in mediating the interactions between DipA and CheA by using a bacterial two hybrid system. We also explored the functional redundancy of ParP and CheW AIF domains with swimming assays and found that ParP’s AIF domain was unable to restore swimming motility in a ∆cheW mutant strain. This research may provide new targets for safe biofilm dispersal within the lungs of cystic fibrosis patients.2020-11-1
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