Goneau L.W.,University of Western Ontario |
Goneau L.W.,Lawson Health Research Institute |
Yeoh N.S.,University of Otago |
MacDonald K.W.,University of Western Ontario |
And 8 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2014
Persister cells represent a multidrug-tolerant (MDT), physiologically distinct subpopulation of bacteria. The ability of these organisms to survive lethal antibiotic doses raises concern over their potential role in chronic disease, such as recurrent urinary tract infection (RUTI). Persistence is believed to be conveyed through global metabolic dormancy, which yields organisms unresponsive to external stimuli. However, recent studies have contested this stance. Here, various antibiotics that target different cellular processes were used to dissect the activity of transcription, translation, and peptidoglycan turnover in persister cells. Differential susceptibility patterns were found in type I and type II persisters, and responses differed between Staphylococcus saprophyticus and Escherichia coli uropathogens. Further, SOS-deficient strains were sensitized to ciprofloxacin, suggesting DNA gyrase activity in persisters and indicating the importance of active DNA repair systems for ciprofloxacin tolerance. These results indicate that global dormancy per se cannot sufficiently account for antibiotic tolerance. Rather, the activity of individual cellular processes dictates multidrug tolerance in an antibiotic-specific fashion. Furthermore, the susceptibility patterns of persisters depended on their mechanisms of onset, with subinhibitory antibiotic pretreatments selectively shutting down cognate targets and increasing the persister fraction against the same agent. Interestingly, antibiotics targeting transcription and translation enhanced persistence against multiple agents indirectly related to these processes. Conducting these assays with uropathogenic E. coli isolated from RUTI patients revealed an enriched persister fraction compared to organisms cleared with standard antibiotic therapy. This finding suggests that persister traits are either selected for during prolonged antibiotic treatment or initially contribute to therapy failure. Copyright © 2014, American Society for Microbiology. All Rights Reserved.
Makaran J.E.,Fanshawe College
IEEE Transactions on Power Electronics | Year: 2010
The following paper presents a novel, empirical approach to gate charge control of a MOSFET used in low-side drive applications such as found in dc motor drives during turn-off, using pulsewidth modulation (PWM) based on ideal expressions of MOSFET behavior during turn- off. Without gate charge control, ringing and overshoot caused by dv /dt effects during the turn-off can result in an increase in electromagnetic interference as well as an increased power dissipation. The ringing can be difficult to suppress through the addition of suppression components as they add cost and bulk to the motor controller. Previous work has focused on the observation of dv/ dt, feed-forward, or open-loop means. Although complex gate charge solutions exist in dedicated application-specific integrated circuits (ASICs), a simple, cost-effective solution is proposed in this paper. This solution differs from previous solutions, making use of the ideal relationship between the drain-to-source and gate-to-source voltage of the MOSFET on turn-off to determine the region of high dv/dt to control a two-staged gate charge removal scheme. This solution can be readily implemented in microprocessor-based control schemes used to control motor drives and switch-mode power supplies utilizing low-side MOSFET switching. Circuit operation and advantages are presented and supported by simulation and experimental results. © 2006 IEEE.
Harper T.,3M |
Fitzgeorge L.,3M |
Fitzgeorge L.,Fanshawe College |
Tritter A.,3M |
Mental Health and Physical Activity | Year: 2013
Purpose: To examine if expectancy beliefs towards exercise reducing smoking craving and withdrawal symptoms are related to these symptoms following an acute bout of exercise for women engaged in a quit attempt involving Nicotine Replacement Therapy (NRT). Method: Participants (n = 149) underwent the 14-week Getting Physical on Cigarettes (GPOC) trial involving exercise and NRT. Exercise expectancy beliefs were collected at baseline (prior to week 1) and at week 5 (one week after quitting smoking and beginning 21 mg patch). At week 5, participants reported craving and withdrawal symptoms immediately prior to and following a 20-minute bout of moderate intensity exercise. To be eligible for subsequent analyses, participants had to demonstrate a carbon monoxide score of <6 ppm, adhere to their NRT program, and follow their acute exercise regime at the appropriate intensity (n = 91). Results: A significant reduction in craving and withdrawal symptoms (i.e. craving, psychological, sedation) was found from pre- to post-exercise at week 5. Exercise expectancy beliefs demonstrated a trend effect increase from baseline to week 5. Both level of exercise expectancy (week 5) and residual change in exercise expectancy (baseline to week 5) were mildly associated with residual change in psychological symptoms, and unrelated to residual changes in craving and sedation. Conclusion: Exercise expectancy increases are unrelated to reductions in cravings and sedation and mildly related to reductions in psychological symptoms following an acute bout of moderate intensity exercise in smokers who have recently attempted to quit. © 2013 Elsevier Ltd. All rights reserved.
Costa M.A.,Fanshawe College
SIGITE'11 - Proceedings of the 2011 ACM Special Interest Group for Information Technology Education Conference | Year: 2011
Qubits, Atoms, Photons, Entanglements, Quantum Mechanics and Diamonds meet the Information Age. Current research indicates that diamonds may hold the key to a cryptanalyst's nightmare,'The unbreakable cipher'. This paper introduces the basic theory and principles behind this innovative technology, reports on the research that has led to present day breakthroughs, investigates those that hold promise and looks at the possibilities for future research in this field. This report is presented as a primer to the'World of Quantum Cryptography'and its impact on Network Security and Management. Consequently, it does not provide any mathematical proofs behind the theoretical models which relate to Quantum Mechanics. It does, however, make reference to and direct those who require this depth of knowledge to the sources if this information is desired or is the basis for further research. © 2011 ACM.
Khalili H.,Fanshawe College |
Orchard C.,University of Western Ontario |
Laschinger H.K.S.,University of Western Ontario |
Farah R.,University of Western Ontario
Journal of Interprofessional Care | Year: 2013
Although health professional educational programs have been successful in equipping graduates with skills, knowledge and professionalism, the emphasis on specialization and profession-specific education has enhanced the development of a uniprofessional identity, which has been found to be a major barrier to interprofessional collaborative person-centred practice (IPCPCP). Changes within healthcare professional education programs are necessary to enable a shift in direction toward interprofessional socialization (IPS) to promote IPCPCP. Currently, there is a paucity of conceptual frameworks to guide IPS. In this article, we present a framework designed to help illuminate an IPS process, which may inform efforts by educators and curriculum developers to facilitate the development of health professions students' dual identity, that is, an interprofessional identity in addition to their existing professional identity, as a first step toward IPCPCP. This framework integrates concepts derived from social identity theory and intergroup contact theory into a dual identity model of IPS. © 2013 Informa UK Ltd.