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Optimization Algorithm to Determine Parameters and Track Nonlinear Dynamic Systems in Pharmacology
No full textPh.D.In mathematical pharmacology, models are constructed to confer a robust method for optimizing treatment. Bridging fundamental approaches to model optimization for pharmacometricians, systems pharmacologists and statisticians is a critical issue. Our research utilizes adaptive chaos synchronization along with grid search and Nelder mead search to estimate physiological and pharmacological systems with nonlinear dynamic characteristics by exploring deterministic methods that are more accurate than classical numerical approaches, which minimize the sum of squares or maximize the likelihood. We illustrate these issues with an established model of cortisol secretion in human subjects with nonlinear dynamic characteristics and tumor immune interaction model with nonlinear dynamic characteristics. We have also demonstrated the accuracy of adaptive chaos synchronization method in terms of low percent error(/discrepancy) in parameter estimates and low RMSE between predictions and observations by applying this method on both simulated (with and without noise) and on real clinical data in comparison to classical approach used for individual analysis. We also explore deterministic contributors to reproducibility and demonstrate that this method could capture and provide insights into how the actual system gives rise to highly variable results. We observed that this approach can be used for tracking nonlinear dynamic systems more accurately (low RMSE between predictions and observations) compared to classical approaches. Our results demonstrate the strength of this approach for exploring noiseless which only consists of deterministic component and demonstrates the weakness of this approach while analyzing real clinical data which consists of both deterministic and stochastic component.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Synthesis, Reactivity, and Thermochemistry of Mn(I) Carbonyl Complexes with Hydroxide and Phenol-Phosphine Ligands
No full textPh.D.Manganese is a first-row transition metal, predominantly found in the Earth's crust where it is the third-most abundant transition metal after iron and titanium. In Industry, manganese is produced on a massive scale and is extensively used in the preparation of metal alloys, catalysts in radical chain aerobic oxidations, and antiknock fuel additives. Manganese also plays an important role in biology as an essential micronutrient that is necessary for the proper functioning of the human body. In plants, manganese is involved in photosynthesis and is a critical component of the oxygen-evolving complex, a tetranuclear Mn4CaO5 center that oxidizes water to O2. Despite being a versatile metal with applications spanning across biology and industry, the chemistry of Mn has lagged behind other transition metals (e.g. iron and copper). However, the 2016 discovery of Mn(I) catalyzed (de)hydrogenations by Milstein and Beller led to an explosion of investigations surrounding the chemistry of Mn(I) all across the globe. While these reports revealed the potential of manganese as a substitute for expensive and toxic metals in catalysis, previous reports from Fan and coworkers showed its potential in hydrogen production and energy science. For instance, they reported that an organomanganese complex, cymantrene (CpMn(CO)3), can photochemically split water to give H2 and H2O2 in stoichiometric amounts. It is interesting to note that the same group reported cymantrene catalyzed photochemical splitting of thiols (RSH) into H2 and disulfides (RS-SR).Inspired by these findings, we investigated the photochemical properties of a known tetrameric complex [Mn(CO)3(µ3-OH)]4 and demonstrated the production of H2 and H2O2 upon irradiation of the complex in a biphasic (water/toluene) mixture. Our studies with this complex revealed some mechanistic insights about the species resulting from disproportionation and disassembly of the cluster. Attempts to stabilize these intermediates for a deeper understanding of the water-splitting mechanism led us to strategically design and develop a phenolic POP pincer ligand platform. Unfortunately, the POP ligands failed at stabilizing the cluster and hence provided no additional insights into the water-splitting chemistry. However, these ligands gave rise to rich coordination chemistry with manganese owing to their hemilabile phenol(ate) group and yielded various mono and multi-nuclear complexes. Screening these complexes for application in catalyzing various organic transformations led to our discovery of the very first Mn(I) catalyzed Tishchenko reaction (conversion of aldehydes to esters). This discovery was a well-timed addition to the extensive list of catalysis carried out by various Mn(I) complexes, reported since the very recent discovery of Mn(I) catalyzed (de)hydrogenations via metal-ligand cooperativity (MLC) in 2016...**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Technological Choice and Human-Animal Relationships: A Bird's Eye View from the Rat Islands, Alaska
No full textPh.D.Human groups have used birds in a variety of ways, from food, to raw material for tools, to clothing. In addition to their more practical usages birds often play a significant role in cosmologies and myths (Serjeantson 2009). However, due to poor preservation and excavation bias (many bird bones are small enough to slip through even 1/4" screens) bird remains have only recently begun to be studied in depth. The archaeological sites of the Aleutian Islands have very large avian bone assemblages due to excellent taphonomic conditions. The large size and excellent preservation of these assemblages allows rigorous study from which we can study not only local relationships with birds but also develop models for other times and places. Comparing the patterns of skeletal part representation with oral histories and ethnographies will reveal the interplay of the symbolic and 'material' aspects of the relationship between birds and the residents of the Aleutian Islands. The relationship between the prehistoric inhabitants of the Rat Islands, the Unangan, and birds was maintained by a suite of continual and often daily practices - from hunting, to story-telling, to subsistence acts. The resulting artifacts of these day-to-day activities, in this case the avian bone assemblage, play a significant role in the reproduction of social and cultural values (Bourdieu 1977; Richardson 1989; Tilley 1989, Sillar and Tite 2000). By studying the technological choices that the Unangan made regarding birds we can begin to examine the more social and even symbolic aspects of the Unangan-bird relationship. This can be accomplished by comparing the skeletal part representation, i.e. which species/families were used for which technology, which parts of the birds were exploited, etc., to the expected patterns of usage based on oral histories and ethnographies. Technological acts are a medium "through which social relationships, power structures, worldviews, and social production and reproduction are expressed and defined (Dobres and Hoffman 1994: 212)." Thus, in order to understand the complex relationship of the Unangan with birds, we must incorporate not only a discussion of human-animal relationships via social zooarchaeology but also a discussion of practice and technological choice.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
The Development of A Next-Generation Human Reliability Analysis: Systems Analysis for Formal Pharmaceutical Human Reliability (SAFPH℞)
No full textPh.D.Medication errors originating in community pharmacies are serious patient safety hazards. However, due to the complexity of the community pharmacy environment, current experimental and observational studies are insufficient to address these problems. This research aims to create a novel, formal, proof-based approach to human reliability analysis (HRA) that will provide pharmacies with the ability to accurately predict error rates, understand why errors are occurring, and better engineer their system to mitigate the errors. Traditional HRA can accurately predict human error rates in a number of environments. However, they are limited in that they are static and thus not able to handle the dynamic environmental elements that can impact human performance. To address this and allow analysts to accurately predict medication error rates, we have developed a next-generation HRA called the Systems Analysis for Formal Pharmaceutical Human Reliability (SAFPHR). This method addresses the limits of previous HRAs by combining concepts from the Cognitive Reliability and Error Analysis Method (CREAM) HRA with probabilistic model checking, a computational tool for automatically proving properties about complex, stochastic systems. By using different estimation methods and cognitive assumptions, we have fully developed the modeling and predictive capabilities of three versions of SAFPHR: basic SAFPHR, CPC-effect extended SAFPHR, and mode-effect extended SAFPHR. These three versions can collectively produce six different methods of computing error rates. To determine which of these estimates were the most accurate and valid, we formally modeled a full, generic, pharmacy dispensing procedure. We then used SAFPHR to make predictions about overall error rates as well as error rates originating from different stages of the dispensing process. These values were computed for all six estimation approaches and then compared with real, comprehensive error rates published in the literature. One method consistently produced accurate predictions both for the overall error rate and the individual stages. The results have important implications for pharmacy because they show that SAFPHR could be used to reduce medication error rates and thus significantly improve patient health and safety. Given its success in pharmacy and the generic nature of its underlying theory, SAFPHR could be used as a general HRA to improve safety and reliability in other critical domains. More avenues of future research are explored in the end.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Three Essays on Social Dynamics in Virtual Communities
No full textPh.D.The advance of information technologies and systems in the era of Web 2.0 has led to the proliferation of virtual communities. These communities provide an interactive platform for people who share common interests and concerns to connect with each other and exchange various information. Previous studies have noted the various social functions afforded by virtual communities, such as the formation of health support forums, knowledge sharing groups, and even grass-root movements that petition for social changes (e.g. Coursaris & Liu, 2009; Liu, Zhang, Susarla, & Padman, 2017; Mo & Coulson, 2008; Ridings & Gefen, 2004; Wang, Kraut, & Levine, 2015; Yan & Tan, 2014). However, the heterogeneity in the motivation and goals of the users means that their experience in the virtual community is often contingent on the way that they interacted with other members in the process and can produce highly individualized outcomes. The proposed dissertation attempts to address three research questions: First, how do users express themselves and elicit response from other members of the community? Second, how do the different outcomes of the interactions influence users' continued engagement in the community? And third, do different users derive higher level of satisfaction from interactions that are more coherent to their goals?**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Ethnography of Multimodal Communication in an English-Medium University-Level Classroom: A Social Semiotic Perspective on Learning
No full textPh.D.Colombian schools and universities currently have entire courses or academic programs that use English as a Medium of Instruction (EMI). It is a common belief that such an initiative will enhance students' acquisition of communicative competences in English as a Foreign Language (EFL) and, consequently, respond effectively to the demands of National Educational Policies (Bonces, 2012; Beltrán, 2011; Corrales & Escamilla, 2016; Mariño, 2014; McDougald, 2009; McDougald, & Anderson, 2015; Zhyrun, 2016). Even though research on English instruction in Colombian academic contexts is vast, it has concentrated on procedural concerns regarding the implementation of teaching methodologies for primary and secondary education. Less has been done, however, in regards to the ways in which communication is configured in EMI in Higher Education (HE) contexts and the role that this communication has in the formation and transformation of the social climate for learning therein and, ultimately, the students' learning. As such, framed within social semiotics, this study examined interactions within a small group of adult students in a business course taught in English at a private university in Bogotá, Colombia. The study has the purpose of accounting for the complex reciprocities among the students' multimodal ways of communicating, the classroom learning climate, and ultimately the students' learning as mediated and evidenced through their interaction in EFL (Kress, 2010, 2011). As such, this ethnographic (Hymes, 1967, 1972, 1974, 1979, 1994) interaction analysis (Kress, 2010, 2011; Norris, 2004) reports findings on communicative events (Aukerman et al., 2017) suggesting that learning results from, and is evidenced through communication which is always multimodal. Findings also unveil ways in which communicative situations are formed and could be transformed in pursuit of learning in the EMI classroom. They suggest that communicative situations in the EMI classroom must be interactive, participative, collaborative, and competitive. Findings also show the ways in which actions in interactions are deployed through a multiplicity of modes—rather than only speech—to accomplish communicative action in the act of learning. Finally, findings fuel a discussion about the implications that this may have for pedagogy and learning in EMI.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
An Investigation of the Risks of Disinfection Byproducts in Wastewater Recycling: From Forward Osmosis Membrane Process to Natural Sunlight Photolysis
No full textPh.D.Wastewater recycling is an important strategy to overcome water scarcity. Wastewater can be treated by reverse osmosis-based full advanced treatment systems to reach drinking water quality for potable reuse. Wastewater recycling can also occur unintentionally (i.e., de facto reuse) where upstream wastewater effluents constitute part of the drinking water source downstream. In both cases, the formation of disinfection byproducts (DBPs) is of concern. DBPs are formed from the reactions between disinfectants (e.g., chlorine) and various water constituents, and they represent one of the major health risks for disinfected wastewater. This dissertation aims to investigate the risks of DBPs in the two scenarios of wastewater recycling. The first part of this dissertation systematically investigated the rejection of DBPs by forward osmosis (FO)...The second part of this dissertation assessed the effects of sunlight on the potential of wastewater effluents to form DBPs in de facto reuse...**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Lame-Footed London: Disability, Drama, and Ideologies of the City in Fin De Siècle England
No full textM.A.The final years of the 16th century were marked by deep uncertainty about the political and social stability of England. Queen Elizabeth I was in her twilight years and concerns over her ailing body and its implications for a healthy body politic were reflected in a broad range of texts that dealt explicitly with relationships between social unity and disabled bodies. This thesis examines two such plays, the anonymous tragedy A Larum for London and Thomas Dekker's city comedy The Shoemaker's Holiday, both produced in the final year of the 16th century, in which visions of a unified London are in fact produced by way of the disabled body. Both plays posit a fantasy of the body politic, moreover, aligned specifically with the embodiment of the disabled veteran. The fantasy of the healthy, unified social body in A Larum for London, I argue, is predicated on cultural logics of unity, derived in large part from medical and philosophical as well as political discourses of the period, that emphasize the necessity of preserving bodily integrity. These discourses inform the metaphorical leap from the disabled body of a single character, Stump, to the unification of the urban body politic against external threats. In creating its vision of a harmonious and unified London, The Shoemaker's Holiday, I argue, relies on contemporary chorographical representations of a walkable urban space that in turn create a coherent social hierarchy. Alongside the entwined ideologies of production and reproduction, the logic of a walkable London works to exclude the disabled veteran Ralph as a valid subject of the urban social order. The thesis turns to disability studies, queer theory, performance studies, and cultural studies paradigms in order to elucidate the ways in which particular forms of disability and disability representation exist as a set of historically-contingent phenomena, as well as an enduring and mutable category of embodiment.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
A Wide-Range Input Auxiliary Power Supply Based on Series-connected SiC MOSFETs for Modular Multi-level Converter
No full textM.S.Auxiliary Power Supply (APS) is required to power the gate drive circuit of IGBT in the Modular Multilevel Converter (MMC). The input voltage of the APS is taken from the DC-link voltage of the submodule capacitor while its output voltage is integrated with the gate drive of the submodule IGBT. Most existing topologies involve a complex circuit design and can only power a single gate drive circuit. This work proposes a novel topology based on single-input multi-output flyback converter with series-connected SiC MOSFETs to power gate drive circuits of both IGBTs inside one submodule. The circuit is designed and the controller is implemented to work with a wide input voltage range while maintaining a constant output voltage. Additionally, pulse transformer and passive snubber schemes are explored to achieve consistent gate signals which avoid the voltage balancing issues in series-connected MOSFETs at the switching transients. In-depth analysis of the proposed topology is presented, along with SPICE simulation verification using models of commercial devices.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Muscle Fatigue Analysis Using EMG Obtained from IoT Based Neurorehabilitation Device
No full textM.S.A popular therapeutic strategy in neurorehabilitation includes the use of transcutaneous electrical nerve stimulation (TENS), which is a noninvasive modality that delivers small electrical impulses through electrodes into muscle tissue. This causes the muscles to contract, and when used as an adjuvant in functional tasks, can assist with the recovery time and outcome in neurorehabilitation. Several studies have shown that TENS is effective for reducing pain and improving physical function. However, the exact effect TENS has on fatigue during functional tasks is unknown since it is often evaluated in a qualitative manner. In order to fully identify the effects of fatigue in neurorehabilitation and to develop optimized control strategies, it is of particular interest to be able to quantify the effects of TENS on functional neuromuscular tasks. Aim: The purpose of the present study is to identify the effect of Transcutaneous Electrical Nerve Stimulation (TENS) quantitatively over both short and long term on muscle fatigue induced by a regular exercise routine from EMG obtained from a IoT based neurorehabilitation device. Methods: Muscle fatigue from EMG was measured as it negatively affects the recovery time experienced through rehabilitation therapy, and is a major underlying phenomenon affecting patient quality of care. In this proof of concept study, a functional resistance-based bicep curl exercises were performed with and without assisted TENS, to measure the effects on muscular performance (i.e., fatigue and fatigue resistance) using the sEMG obtained by tele rehabilitation device. The tele rehabilitation device consists of real time monitoring of cloud based system to monitor EMG in real time and IoT based mobile application to control the application of TENS. Results: The experiments showed that during both short-term comparison (set-to-set measurements on the same day) and long term (regularly performed over 3 months), the TENS assisted exercise shows an increased muscle fatigue resistance vs the exercise without TENS. In long term a 1.17 dB decrease in sEMG amplitude due to improved muscle resistance when compared to muscles that did not undergo stimulation. A T-test between the power values of the two groups of data over long term (p<0.05) also showed that they were statistically significant. These results suggest that the TENS reduces muscle fatigue in the same manner as increased loading in a functional exercise. Thus, showing that TENS can be used to increase the difficulty in an exercise strategy (athletes, and post-stroke rehabilitation), and it can be optimized to create personalized therapeutic strategies based on the patient's neuromuscular ability. Conclusion: An improved muscle fatigue resistance was seen in muscle exercised with TENS over the muscle exercised without TENS, thus showing that TENS can be effectively used through an IoT device to increase the difficulty in an exercise regimen for athletes and post stroke.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*