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- Genre: Doctoral Dissertation
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Description
Magnetic Resonance Imaging has become an increasingly reliable source of medical imaging to obtain high quality detailed images of the human anatomy. Application specific coil or an array of coils when placed closely to the anatomy produces high quality image due to the improved spatial signal to noise ratio. Elastic RF coils have been shown to conform to the shape of the patient’s body and drastically reduce the gap between coil and anatomy. First, a major challenge faced by these elastic RF coils is the changing impedance condition as the coil takes a different shape for every individual. Next, an area that could benefit from the improved image quality and patient comfort that comes from flexible RF coil design is endorectal prostate imaging. Demonstrated in the first part of this dissertation is a modular solution to compensate the impedance mismatch. Standalone Wireless Impedance Matching (SWIM) system is an automatic impedance mismatch compensation system that can function independently of the MR scanner. The matching network consists of a capacitor array with RF switches to electronically cycle through different input impedance conditions. The SWIM system can automatically calibrate an RF coil in 3s with a reflection coefficient of less than -15dB resulting in improved Signal-to-noise ratio (SNR) of the sample image by 12% - 24%, based on sample size, when compared to a loaded coil without retuning.
For the second part, we propose a novel elastic and inflatable RF coil integrated with the SWIM system for endorectal prostate imaging at 9.4T. A silicone polymer substrate filled with liquid metal alloy is designed and fabricated with a cavity to create ii inflation. This inflatable RF coil is combined with the SWIM system to automatically tune and match after inflating the RF coil for individual levels of inflation. The imaging results have shown a ~10%, ~19%, and ~25 % increase in SNR due to inflation of RF coil at different ROIs in the acquired image. Overall, the methods proposed and discussed in this thesis are a step towards a new generation of RF coil systems for both existing applications and upcoming ones.
ContributorsKandala, Sri Kirthi (Author) / Sohn, Sung-Min (Thesis advisor) / Kdibagkar, Vikram (Committee member) / Sadleir, Rosalind J (Committee member) / Beeman, Scott (Committee member) / Trichopoulos, Georgios (Committee member) / Arizona State University (Publisher)
Created2023
Description
Non-invasive visualization of the trigeminal nerve through advanced MR sequences and methods like tractography is important for studying anatomical and microstructural changes due to pathology like trigeminal neuralgia (TN), facial dystonia, multiple sclerosis, and for surgical pre-planning. The use of specific anatomical markers from CT, MPRAGE and cranial nerve imaging (CRANI) sequences, enabled successful tractography of patient-specific trajectory of the frontal, nasociliary, infraorbital, and mandibular nerve branches extending beyond the cisternal brain stem region and leading to the face. Performance of MPRAGE sequence together with the advanced T2-weighted CRANI sequence with and without a gadolinium contrast agent, was studied to characterize identification efficiency in smaller nerve structures in the extremities. A large FOV nerve visualization exam inclusive of the anatomy of all trigeminal nerve distal branches can be obtained within an acquisition time of 20 minutes using pre-contrast CRANI and MPRAGE. Post-processing with MPR and MIP images improved nerve visualization.Transcranial electrical stimulation techniques (TES) have been used for the treatment of multiple neurodegenerative diseases. These techniques involve placing electrodes on the scalp with multiple peripheral branches of the trigeminal nerve crossing directly under that may be stimulated. This was studied through hybrid computational realistic axon models. These models also facilitated studying the effects of electrode drift during experiments on the recruitment of peripheral nerves. An optimal point of lowest threshold was found while displacing the nerve horizontally i.e., the activation thresholds of both myelinated and unmyelinated axons increased when the electrodes were displaced medially and decreased to a certain extend when the electrodes were displaced laterally, after which further lateral displacement led to increase of thresholds. Inclusion of unmyelinated axons in the modeling provided the capability of finding maximum stimulation amplitude below which side effects like pain sensation may be avoided. In the case of F3 – F4 electrode montage the maximum amplitude was 2.39 mA and in case of RS – LS montage the maximum amplitude was 2.44 mA. Such modeling studies may be useful for personalization of TES devices for finding optimal positioning of electrodes with respect to target and stimulation amplitude range that minimizes side effects.
ContributorsSahu, Sulagna (Author) / Sadleir, Rosalind (Thesis advisor) / Tillery, Stephen H (Committee member) / Crook, Sharon (Committee member) / Beeman, Scott (Committee member) / Abbas, James (Committee member) / Arizona State University (Publisher)
Created2023
Description
Allogeneic islet transplantation has the potential to reverse Type 1 Diabetes in patients. However, limitations such as chronic immunosuppression, islet donor numbers, and islet survival post-transplantation prevent the widespread application of allogeneic islet transplantation as the treatment of choice. Macroencapsulation devices have been widely used in allogeneic islet transplantation due to their capability to shield transplanted cells from the immune system as well as provide a supportive environment for cell viability, but macroencapsulation devices face oxygen transport challenges as their geometry increases from preclinical to clinical scales. The goal of this work is to generate complex 3D hydrogel macroencapsulation devices with sufficient oxygen transport to support encapsulated cell survival and generate these devices in a way that is accessible in the clinic as well as scaled manufacturing. A 3D-printed injection mold has been developed to generate hydrogel-based cell encapsulation devices with spiral geometries. The spiral geometry of the macroencapsulation device facilitates greater oxygen transport throughout the whole device resulting in improved islet function in vivo in a syngeneic rat model. A computational model of the oxygen concentration within macroencapsulation devices, validated by in vitro analysis, predicts that cells and islets maintain a greater viability and function in the spiral macroencapsulation device. To further validate the computational model, pO2 Reporter Composite Hydrogels (PORCH) are engineered to enable spatiotemporal measurement of oxygen tension within macroencapsulation devices using the Proton Imaging of Siloxanes to map Tissue Oxygenation Levels (PISTOL) magnetic resonance imaging approach. Overall, a macroencapsulation device geometry designed via computational modeling of device oxygen gradients and validated with magnetic resonance (MR) oximetry imaging enhances islet function and survival for islet transplantation.
ContributorsEmerson, Amy (Author) / Weaver, Jessica (Thesis advisor) / Kodibagkar, Vikram (Committee member) / Sadleir, Rosalind (Committee member) / Stabenfeldt, Sarah (Committee member) / Wang, Kuei-Chun (Committee member) / Arizona State University (Publisher)
Created2023
Description
Experiential learning has gained the attention of higher education institutions, specifically business schools, as a way to bring the business world into the classroom. It has become a fundamental methodology for designing business schools' curricula that promotes 21st-century skills like problem-solving, creativity, and teamwork. This study evaluates an experiential learning-based undergraduate business program and its signature entrepreneurship course. The goal is to understand how the entrepreneurship course and its experiential learning component, design sprint, influence first-year students' entrepreneurial mindset, creative self-efficacy and teamwork self-efficacy. Additionally, this study aims to understand the perceptions of first-year undergraduate students of their experiential activities and how they make sense of these experiences.
This action research study draws from theories of learning and psychology, such as Experiential Learning Theory (ELT) by Kolb (1984, 2015); mindset theory by Dweck et al. (1995) and Dweck (2006); self-efficacy by Bandura (1977, 1997); and figured worlds by Holland et al. (1998). These theories support the research questions by emphasizing the collaborative nature of learning, how beliefs about learning, intelligence, and capabilities influence an individual's behavior, and how the environment shapes an individual's interpretation of the world.
This mixed-methods action research study combines quantitative data in the form of a pre and post-intervention survey. The qualitative data was gathered from interviews that focused on understanding the experiences of participating students and their perceptions of their learning after the intervention workshop. Additionally, qualitative data included a feedback survey after the workshop to learn students' perceptions of the intervention activities.
The results of this study suggest that experiential learning activities support students' growth of their creative skills and help them view entrepreneurship from a user-centered perspective. Additionally, results suggested that short-term experiential projects tend to inhibit students from growing in their teamwork skills as they focus all their attention to their project. Lastly, results suggest experiential learning programs can become a space for collaboration, skill development, and motivated students. However, it can also lead to students feeling frustrated and alienated due to the professional codes permeating experiential settings. The study concludes with several implications for practitioners.
ContributorsFrias Vargas, Alfonsina (Author) / Carrillo, Juan (Thesis advisor) / Henriksen, Danah (Thesis advisor) / Mishra, Punya (Committee member) / Arizona State University (Publisher)
Created2023
Description
This multimodal study brought an open, constructively critical challenge to the standard means of process in, and knowledge production from, qualitative inquiry. Using as a context, dyslexia, and the assistive technology lifeworlds of postsecondary students, this study co-partnered with six college students with dyslexia. Co-partnership allowed for an emergence of new awareness that the experience of dyslexia and assistive technology is mediated through innumerable dynamics of interactions with and through the world. Methodologically, the study suggested that it is possible to: (a) situate, center, and validate disability throughout all phases of qualitative inquiry; (b) make the discrete parts of action research more inclusive of disability; (c) reduce physical and intellectual access barriers to qualitative inquiry; and (d) regard as reasonable and rigorous research that is produced by bodies and minds that may not process information in typical ways. Emancipatory action research was used to thread together an understanding of the complexities of self, being, and reality for a marginalized group and how systems, structures, interactions, spaces, and language are superimposed on experiences of disability. The emancipatory spirited study allowed space for co-constructed meaning making through dynamic multimodalities of method including audio-visual data co-constructed through narrative storytelling; an analysis through deep listening and video editing – illuminating ‘bright spots’ in the broader lifeworld perspective of dyslexia and assistive technology. The innovative co-constructed products of the dissertation were a 2-hour film, a researcher reflection video, professional development guides for assistive technology and qualitative inquiry, and a methods chapter as part of an edited book prospectus. By engaging with this study, the audience will experience consciousness raising with respect to disability experience and witness a reclaiming of the voice of that experience through inclusive research. This study offers a transformative perspective for future work by inviting critical consideration and co-construction of meaning of an expanded conceptualization of assistive technology as an embodied, negotiated experience; and increases awareness that diverse bodyminds offer powerful narratives of diversity in the human condition and why that matters. .
ContributorsBunch, Jacob Colby (Author) / Graves-Wolf, Leigh (Thesis advisor) / Bowers, Nicole (Thesis advisor) / Harrop, Lance (Committee member) / Nusbaum, Emily A. (Committee member) / Arizona State University (Publisher)
Created2023
Description
There has been an ever-increasing demand in the United States to produce educated science, technology, engineering and mathematics (STEM) professionals. Because more women and minority students have begun their higher educational preparation at community colleges, these institutions have been uniquely positioned to support these students and increase the number of STEM graduates. Nevertheless, to attain this commendable goal, community college staff and faculty members will need to redouble their efforts to provide active and sustained programs and interventions to support and assure student persistence in STEM fields.
To address the problem of practice, the researcher engaged in a variety of validating practices to influence women and minority students’ intent to persist in a STEM degree. Thirteen, first-year women and minority students participated in the study. Validation theory (Rendón, 1994) provided a framework to inform the intervention and forms of validation. The validating practices included two advising visits and intentional email communications to students in their first semester at community college.
A mixed methods approach was employed to examine two objectives: (a) the types of validation students experienced in their first semester and (b) the influence of validating advising practices on intention to persist in STEM. The Theory of Planned Behavior (TPB; Ajzen, n.d.) guided study efforts in relation to the second objective. Data gathered included survey data, interviews, email communications, and researcher journal entries. Results suggested students experienced academic and interpersonal validation by in-class and out-of-class validating agents. Although not all experiences were validating, students were validated to a greater extent by their academic advisor. Because of validating advising practices, students in this study developed confidence in their ability to be capable college students. Students also felt motivated and expressed intentions to persist toward a STEM degree.
The discussion focuses on explaining outcomes of the four research questions by connecting to the extant literature. In addition, limitations of the study are presented. Finally, implications for practice, implications for future research, and lessons learned are also shared.
To address the problem of practice, the researcher engaged in a variety of validating practices to influence women and minority students’ intent to persist in a STEM degree. Thirteen, first-year women and minority students participated in the study. Validation theory (Rendón, 1994) provided a framework to inform the intervention and forms of validation. The validating practices included two advising visits and intentional email communications to students in their first semester at community college.
A mixed methods approach was employed to examine two objectives: (a) the types of validation students experienced in their first semester and (b) the influence of validating advising practices on intention to persist in STEM. The Theory of Planned Behavior (TPB; Ajzen, n.d.) guided study efforts in relation to the second objective. Data gathered included survey data, interviews, email communications, and researcher journal entries. Results suggested students experienced academic and interpersonal validation by in-class and out-of-class validating agents. Although not all experiences were validating, students were validated to a greater extent by their academic advisor. Because of validating advising practices, students in this study developed confidence in their ability to be capable college students. Students also felt motivated and expressed intentions to persist toward a STEM degree.
The discussion focuses on explaining outcomes of the four research questions by connecting to the extant literature. In addition, limitations of the study are presented. Finally, implications for practice, implications for future research, and lessons learned are also shared.
ContributorsSanchez, Nuria Maria (Author) / Buss, Ray (Thesis advisor) / Sampson, Carrie (Committee member) / Lara, Ernest (Committee member) / Arizona State University (Publisher)
Created2020
Description
American Indian youth are experiencing a mental health crisis fueled by the lingering ramifications of experiencing a near cultural genocide. Scholarly literature indicates that American Indians have used their cultural values to survive the atrocities associated with colonization. The purpose of this Indigenous based mixed-methods action research project was to examine how Blackfoot elders perceive the transfer of values through ceremonies, cultural activities and traditional stories; and to what degree a Blackfoot way of knowing paradigm informs cultural connectedness, and school connectedness for students attending school on the Blackfeet Indian Reservation. The study was conducted through a Blackfoot way of knowing paradigm and consisted of two distinct but related data collection efforts. The first sample consisted of formal and informal interviews with 26 American Indian elders as well as observation notes from attending and participating in American Indian ceremonies in order to discover the traditional values believed transferred during ceremonies, cultural activities, and traditional stories. The elder interviews resulted in identifying ten traditional values encasing spirituality displayed in the Hoop of Traditional Blackfoot Values. The second sample consisted of 41 American Indian youth attending school on the Blackfeet Indian Reservation. The youth learned the values identified in the Blackfeet Education Standards “Hoops of Values” through a Blackfoot way of knowing paradigm and completed measures to assess cultural connectedness and school connectedness. In addition, all students were interviewed to develop a more robust understanding of the role culture plays in cultural connectedness and school connectedness and to lend a Blackfoot youth perspective to a Blackfoot way of knowing. Quantitative data analysis showed that a Blackfoot way of knowing paradigm significantly influences cultural connectedness but does not significantly influence school connectedness. In addition, analysis of the student interviews provided a Blackfeet youth perspective on cultural connectedness and school connectedness.
ContributorsClark, Shawn Douglas (Author) / Wylie, Ruth (Thesis advisor) / Marley, Tennille (Committee member) / Johnson, Lester (Committee member) / Arizona State University (Publisher)
Created2020
Description
Utilizing action research and a qualitative research study design, the purpose of this study was to glean how participation in the Building Community Through Discourse Intervention (BCTD intervention) influenced the cultural and social awareness of six Development and Alumni Relations (DEVAR) managers at The University of California, Davis (UC Davis). To investigate DEVAR managers’ comfort, knowledge, and skills discussing and advocating for diversity and inclusion (D&I), the BCTD intervention featured four topical units: racial issues in the workplace, privilege issues in the workplace, identity issues in the workplace, and applying theory to practice. Over ten weeks, DEVAR managers were required to read assigned chapters from So You Want to Talk About Race by Ijeoma Oluo, watch proposed videos related to D&I, maintain a participant journal to reflect on their experiences throughout the study, and engage in bi-weekly focus group discussions hosted via Zoom to review the prescribed learning material. Guiding the study were two theoretical frameworks: Communities of Practices and a Pedagogy of Discomfort. Through narrative analysis, a storytelling approach was used to present the findings of the study based on four themes derived from the data: the impact of fear on managers’ willingness to advocate for D&I, the importance of dialogue and the role of time in the learning process, and the need for more skills to adequately apply learning to practice. The study discovered that the BCTD intervention improved the comfort and knowledge of DEVAR managers to discuss and advocate for D&I. However, the study did not favorably affect their ability to transfer their increased understanding of the challenges of diverse staff to their managerial practice. Subsequently, as academia and private businesses alike begin to place a greater emphasis on social justice, implications for future research entail: expanding the length of time to conduct a similar situated or designed study to focus on providing participants with enhanced learning opportunities to improve their ability to apply their learning to practice, in-person focus group discussions as opposed to Zoom, and increased representation amongst study participants to enhance the richness of shared experiences.
ContributorsJackson, Craig L (Author) / Markos, Amy (Thesis advisor) / Wolf, Leigh (Committee member) / Keister, Shaun (Committee member) / Hilton, Adriel (Committee member) / Antonucci, Mark (Committee member) / Arizona State University (Publisher)
Created2021
Description
This mixed methods action research study was conducted in a Title I, K-12 public charter school with the purpose of exploring teachers’ capacities to implement student-centered learning after participating in effective professional development (PD). Participants attended a PD cycle where the staff chose the topic, learning was sustained over a three-month period, and teachers received monthly feedback on classroom observations through personalized coaching. The guiding framework for this study was sociocultural theory because the PD design mirrored student-centered learning where the teacher is seen as a guide alongside the student. In this theory, meaning making is a social experience where perspectives of both the teacher and the student contribute to creating new knowledge. Quantitative data collected included a pre-/post-study survey and classroom observations scored on a rubric, and qualitative data consisted of exit interviews. All data was collected and analyzed concurrently, and a researcher’s journal assisted in real-time by providing a space for reflection that was used to determine PD needs, coaching conversations, and interview questions. Quantitative data revealed that the teachers perceived the intervention as slightly boosting their capacity to implement student-centered learning; however, the classroom observations indicated that teachers did not reach levels of proficiency. Through thematic analysis of the qualitative data, six themes emerged, which support the idea that PD can be a transformative experience when it is centered around praxis: 1) collaboration with colleagues, 2) PD gives teachers new ideas, 3) classroom feedback is valuable, 4) teacher reflection, 5) thought partnership, and 6) student choice. The discussion includes limitations and implications for future practice.
ContributorsLoveall, Jill Nicole (Author) / Richardson, Carmen (Thesis advisor) / Frias, Elizabeth (Committee member) / Haddy, Lana (Committee member) / Arizona State University (Publisher)
Created2024
Description
The Pennsylvania Department of Education recently adopted the new academic standards for Science, Technology & Engineering, and Environmental Literacy and Sustainability (STEELS). Scaling STEELS across the commonwealth is a challenging endeavor that depends upon local school districts' implementation of STEELS-based instruction. Therefore, it behooves local school districts to develop strategies supporting local STEELS adoption. The current action research study examined the influence of an intervention built around a Professional Learning Community (PLC) to support a local school district’s implementation of STEELS guided by the Concerns Based Adoption Model (CBAM; Hall & Hord, 2020). Four secondary science teachers from the Bellwood-Antis School District participated in a PLC. The implementation process of the PLC group was measured via the three diagnostic dimensions of CBAM: Innovation Configurations (IC), Stages of Concern (SoC), and Levels of Use (LoU). A concurrent mixed-methods action research design was employed to collect and analyze CBAM measures. The SoC dimension was measured quantitatively via the Stages of Concern Questionnaire. Individual scores were converted to a whole-group PLC SoC Profile for analysis. SoC, LoU, and IC dimensions were assessed qualitatively via semi-structured interviews. Meta-inferences were developed from combined data analysis of quantitative and qualitative data. A CBAM diagnosis for the PLC group was the primary outcome of this action research cycle, which indicated that the PLC members moved into the early phases of implementation during the intervention. Findings from the current cycle of action research informed an updated intervention game plan to be used in the next phase of implementation.
ContributorsMartin, Travis (Author) / Boutot, Amanda (Thesis advisor) / Coudret, Dude (Committee member) / Wagner, Don (Committee member) / Arizona State University (Publisher)
Created2024