2017 MU dissertations - Access restricted to MU
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Item Development of novel site-specific imaging probes for prostate cancer detection(University of Missouri--Columbia, 2017) Jiang, Lingyan; Ma, Lixin[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Molecular imaging is believed to play a pivotal role in decreasing cancer mortality and improving prognosis in the new era. It relies on molecular probes to image cellular or molecular abnormalities in living body. The primary objective of this research is to develop novel multimodal molecular imaging probes, via nanotechnology and peptide conjugation chemistry, for site-specific targeting and imaging of human prostate cancers. A novel nanoparticle based bimodal MRI/fluorescence molecular imaging probe was developed, characterized, and studied for its capacity to target gastrin releasing peptide receptor (GRPr) which is overexpressed in human prostate cancer. Synthesized USPIO(Cy7.5)-BBN nanoparticles have a small core size (5 nm), a high MRI relaxivity, and a superior binding affinity and specificity to the GRPr overexpressed on human prostate cancer in vitro and in vivo. Furthermore, SIO-AF750-BBN, a silica-coated iron oxide nanoparticle loaded with near infrared fluorescence (NIRF) dyes and bombesin, was developed as a tri-modal photoacoustic (PA), NIRF and MRI imaging probe. SIO-AF750- BBN displayed a high binding affinity and specificity to the GRPr expressed prostate cancer cells in vitro and in vivo. SIO-AF750-BBN demonstrated a significant photoacoustic contrast enhancement in tumor tissues, i.e. 3 and 5-fold as compared to the receptor-blocking control group and the peptide analog AF750-BBN without attachment to a nanoparticle, respectively, after intravenous tail vein injection in tumor bearing mice. In addition to bombesin agonist as the targeting moiety, bombesin antagonist is also explored. A series of bombesin antagonists with three different NIRF dyes and three pharmacokinetic modifiers were synthesized and characterized. Of those, three bombesin antagonist analogs, AF750-G-pip-Sta-BBN, AF750-GSG-Sta-BBN, and AF750-6Ahx-Sta-BBN, exhibited high NIRF imaging efficacy, high binding specificity and inffinity, and antagonism to human PC-3 prostate cancer cells both in vitro and in vivo. In conclusion, this Ph.D. work addresses the issues of discovery and development of novel site-specific and multi-modality molecular probes for cancer targeted imaging. USPIO(Cy7.5)-BBN displayed the capacity to generate imaging contrast enhancement for prostate tumors in living bodies on MRI/NIRF. The SIO-AF750-BBN demonstrated tumorspecific photoacoustic signal enhancement, as well as near-infrared fluorescent imaging enhancement after intravenous administration of this agent in human prostate cancer animal model. Finally, AF750 labeled bombesin antagonist analogs were developed and demonstrated to have a high binding affinity and selectivity to the GRPr and a desirable in vivo bio-distribution profile, indicating their high potentials to be translated to clinical use for imaging-guided surgery and therapy.Item Impact of ImPACT : a program evaluation of a northwest Missouri school distric's impact concussion program(University of Missouri--Columbia, 2017) Callaway, Jason Wellington; Edmonds, Carole[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The purpose of this qualitative case study program evaluation was to explore the current process being used to implement the ImPACT concussion program in a Northwest Missouri School District (District X). In addition, this study also added to the body of literature regarding the evaluation of the implementation of concussion programs under the Missouri Concussion Law. This study was guided through the lenses of Rational Choice Theory and Program Evaluation to aid the focus of the study. The overarching questions that guided the research are as followed; what were the intended purposes of District X‟s ImPACT program? What process and procedures have been put into place to fulfill the intended purposes and State mandates? How are athletes, coaches, administration, doctors, parents and teachers educated about the ImPACT program? How are athletes, coaches, administration, doctors, parents, teachers implementing process and procedures of the ImPACT program? This qualitative study used review of previous literature, document review, interviews, observations field notes and focus groups to obtain data. Findings of the data took the form of five themes. The themes were theme one there is a need for the ImPACT program. The second theme Program is conceptualized in a manner that will work, Theme three ImPACT program was implemented according to programming, theme four ImPACT has an impact on intended targets and Theme five Cost Effectiveness. The findings from the study provide District X and any other district implications of practice when implementing an ImPACT concussion program for their athletes and areas to consider when doing a program evaluation to ensure program success.Item Learning from screencast videos for software training : a comparison of dual and single-monitor learning environments(University of Missouri--Columbia, 2017) Kueker, Douglas Paul; Moore, Joi L., 1966-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Learning to use software programs using worked examples in screencast videos presents a classic split-attention problem that requires learners to mentally integrate information from the video with a target application. While much is known about sound screencast tutorial design, little is known about the features of the learning environment, such as monitor configuration, that may influence learning from this form of instruction. An experiment was conducted with 42 novice learners to fill this gap by comparing the effects of two common monitor configurations which split attention in different ways. In one condition, subjects split attention temporally by toggling back and forth between the video and target application on one monitor, while the other condition required subjects to split attention spatially by shifting their gaze between the video and target application displayed on two side-by-side monitors. Effects due to the monitor set-up were assessed for measures of cognitive load, instructional efficiency, and motivation using a 2x2 study design that controlled for task order. Results indicated that cognitive load as measured through task evoked pupil response was significantly higher, p<.05, for groups with two monitors during both instruction and testing, even after controlling for working memory capacity. Analyses of three gaze-related eye-tracking metrics and NASA-TLX ratings did not indicate any differences in workload due to the experimental treatment; however, attentional patterns indicated by the eye-tracking data were shaped by two- and three-way interactions between working memory capacity and the experimental conditions. Measures of instructional efficiency indicated that the single monitor set-up was most efficient as learners attempted to transfer learning. While task efficacy and relevance ratings increased after training, monitor set-up did not affect post-training motivation.Item Variations of disinfection by-product precursors of stream systems in north Missouri watersheds of drinking water supply reservoirs(University of Missouri--Columbia, 2017) Ramolino, Latitia; Clevenger, Thomas E.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during water treatment are of great public health concern. The link between temporal patterns of terrestrial DOM quantity and quality of stream systems in north Missouri watershed of drinking water supply reservoirs was explored to assess catchment controls on stream water DOM chemical composition and reactivity in DBP formation. TCM (trichloromethane) was the dominant of trihalomethane (THM) species and trichloroacetic acid (TCAA) and DCAA (dichloroacetic acid) were the dominant of haloacetic acid (HAA) species formed in chlorinated stream water samples. N-nitrosodimethylamine (NDMA) formed in chloraminated stream water samples. Catchment land uses and soil characteristics of northern Missouri and their impact on watershed hydrology were the most controlling factors of terrestrial DOM transport and transformation in Northern Missouri sub-watersheds. DOM chemical interactions with clay mineral soil surfaces along water flow paths and residence time within catchments were in large responsible for variations of stream water DOM chemical composition. The chemical and structural reactivity of TCMFP, TCAAFP, DCAAFP and NDMAFP precursors in North Missouri stream water DOM were intrinsically coupled together and both seasonally varied in function of mixed effects of anthropogenic land uses and hydrogeochemical sorption processes within catchments that controlled aromaticity and organic nitrogen contents of North Missouri stream water DOM. Organic nitrogen and aromaticity contents of precursor organic moieties in north Missouri stream water DOM controlled DBP formation potentials. Hydrophobic nitrogen-rich aromatic compounds gave the lowest TCM, TCAA, DCAA and NDMA formation potentials, respectively. Hydrophobic carbon-rich aromatic TCMFP precursors were the most reactive with respect to chloroform formation potential. Hydrophilic nitrogenous aliphatic organic micronutrients were more potent TCMFP precursors than hydrophobic and hydrophilic nitrogen containing aromatic organic compounds. Nitrogenous aliphatic micronutrients and nitrogen-rich aliphatic compounds had the largest NDMAFP and DCAAFP yields, respectively. Hydrophilic nitrogenous aromatic organic micronutrients and hydrophilic nitrogen containing aromatic organic compounds facilitated TCAA formation potential compared to more hydrophobic nitrogen containing aromatic compounds. Understanding of how north Missouri catchment anthropogenic land uses affect the mobilization of precursor material can help in establishment of effective monitoring programs. Evaluating DBP chemical and structural transformations during their transport to drinking water sources can help to implement effective watershed management policy to reduce DBPs transfer from watershed to drinking water sources.Item Understanding the development of a 6th grade science classroom practice of argumentation : synthesizing cognitive and sociocultural perspectives(University of Missouri--Columbia, 2017) Cite, Suleyman; Sadler, Troy D.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Recent science standards have underlined the importance of engaging students in scientific practices for learning science ideas as well as develop understandings about the ways in which scientific knowledge is constructed. As such, scientific argumentation, one of the central practices of science, has gained interest among science educators. Looking across the studies focusing on incorporating scientific argumentation into science classroom, two prominent approaches, cognitive and sociocultural, stand out regarding the incorporation of scientific argumentation into science classrooms. While cognitive perspective focuses on characterizing the nature of student competence in argumentation and understanding the individual student development of argumentation competence, sociocultural perspective seeks to understand the ways in which student competence can be facilitated by the contextual features of a classroom community. By bringing these two distinct but complementary perspectives together in this dissertation study, we proposed four manuscripts to understand the development of a 6th grade science classroom argumentation practice. The results of this dissertation study suggested that individual student's development of argumentation competence was mediated by the classroom norms around discourse. The implications for future research and curriculum design are discussed.