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Description
The viscous lung mucus of cystic fibrosis (CF) patients is characterized by oxygen gradients, which creates a unique niche for bacterial growth. Pseudomonas aeruginosa and Staphylococcus aureus, two predominant microorganisms chronically infecting the airways of CF patients, typically localize in hypoxic regions of the mucus. While interspecies interactions between P. aeruginosa and S. aureus have been reported, little is known about the role of low oxygen in regulating these interactions. Studying interspecies interactions in CF lung disease is important as evidence suggests that microbial community composition governs disease progression. In this study, P. aeruginosa lab strain PAO1 and two primary clinical isolates from hypoxic tissues were cultured alone, or in combination, with methicillin resistant S. aureus (MRSA) strain N315 under hypoxic or normoxic conditions. Herein, it is shown for the first time that low oxygen conditions relevant to the CF lung affect the competitive behavior between P. aeruginosa and S. aureus. Specifically, S. aureus was able to better survive competition in hypoxic versus normoxic conditions. Competition data from different oxygen concentrations were consistent using PAO1 and clinical isolates even though differences in the level of competition were observed. PAO1 strains carrying mutations in virulence factors known to contribute to S. aureus competition (pyocyanin/phzS, elastase/lasA and lasI quorum sensing/lasI) were used to determine which genes play a role in the differential growth inhibition. The lasA and lasI mutants competed less effectively with S. aureus regardless of the oxygen level present in the culture compared to the isogenic wild type strain. These results are consistent with previous findings that elastase and lasI quorum sensing play a role in competitive behavior of P. aeruginosa and S. aureus. Interestingly, the phzS mutant competed less effectively in hypoxic conditions suggesting that pyocyanin may be important in microaerophilic conditions. This study demonstrates that oxygen plays a role in competition between P. aeruginosa and S. aureus and contributes to understanding CF environmental factors that may regulate microbial community dynamics important for disease progression with potential for development of therapeutic avenues.
ContributorsLedesma Barrera, Maria Alexandra (Author) / Nickerson, Cheryl A. (Thesis advisor) / Reyes del Valle, Jorge (Committee member) / Clark-Curtiss, Josephine (Committee member) / Stout, Valerie (Committee member) / Ott, C M (Committee member) / Arizona State University (Publisher)
Created2014
Description
In competitive Taekwondo, Electronic Body Protectors (EBPs) are used to register hits made by players during sparring. EBPs are comprised of three main components: chest guard, foot sock, and headgear. This equipment interacts with each other through the use of magnets, electric sensors, transmitters, and a receiver. The receiver is connected to a computer programmed with software to process signals from the transmitter and determine whether or not a competitor scored a point. The current design of EBPs, however, have numerous shortcomings, including sensing false positives, failing to register hits, costing too much, and relying on human judgment. This thesis will thoroughly delineate the operation of the current EBPs used and discuss research performed in order to eliminate these weaknesses.
ContributorsSpell, Valerie Anne (Author) / Kozicki, Michael (Thesis director) / Kitchen, Jennifer (Committee member) / Electrical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Theme parks have been expanding in size and scope since their inception decades past, a trend that the academic world has begun to notice. There is a wide variety of academic literature on tourism, but not nearly as much on theme parks. As a unique entertainment concept, theme parks have yet to be studied as extensively as other tourism settings. The purpose of this study is to expand on the current academic research concerning theme parks. The researcher applied directed content analysis to dozens of mass media articles in an attempt to identify strategies currently in use in the theme park industry, thereby filling a gap in academic research on the practical application of strategy in the theme park industry. The content analysis consisted of 87 articles from 34 United States-based sources ranging in year from 1985 to 2013, including both large- and small-scale publications, in regards to circulation, spanning the entire country. At the conclusion of the data collection process, the researcher recorded 225 statements demonstrating eight distinct strategies historically present in the theme park industry. The statements from the articles were extracted, analyzed and categorized as discussed below. Those strategies fit into the following eight categories: (1) value, (2) uniqueness, (3) niche, (4) innovation, (5) variety, (6) quality, (7) currency, and (8) convenience. Results from this study introduced two new key strategies being applied in the theme park industry that had not been previously included in the academic literature. The first new strategy discovered was currency. The strategy of providing something current means the theme park attempted to give its guests experiences that were culturally relevant at that time and modern in the theme itself, like creating a ride from a new movie. The second new strategy was convenience, in which case the theme park attempted to make its experiences more accessible for a single member in a party, or the entire group. Both of these new strategies appeared frequently, often more than the six strategies originally identified in the academic literature review. As theme parks continue to grow and diversify in the United States and around the world, it is important for professionals in tourism and business to understand the industry's progression. By combining previous knowledge and adding new research, this study has provided a foundation for future research and analysis on the dynamics of the theme park industry on a national and international scale.
ContributorsLillestol, Tayllor Paige (Author) / Timothy, Dallen (Thesis director) / Goodman, Rebekka (Committee member) / College of Public Programs (Contributor) / Barrett, The Honors College (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor)
Created2014-05