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- Genre: Doctoral Dissertation
- Member of: ASU Electronic Theses and Dissertations
Description
This work explores how flexible electronics and display technology can be applied to develop new biomedical devices for medical, biological, and life science applications. It demonstrates how new biomedical devices can be manufactured by only modifying or personalizing the upper layers of a conventional thin film transistor (TFT) display process. This personalization was applied first to develop and demonstrate the world's largest flexible digital x-ray detector for medical and industrial imaging, and the world's first flexible ISFET pH biosensor using TFT technology. These new, flexible, digital x-ray detectors are more durable than conventional glass substrate x-ray detectors, and also can conform to the surface of the object being imaged. The new flexible ISFET pH biosensors are >10X less expensive to manufacture than comparable CMOS-based ISFETs and provide a sensing area that is orders of magnitude larger than CMOS-based ISFETs. This allows for easier integration with area intensive chemical and biological recognition material as well as allow for a larger number of unique recognition sites for low cost multiple disease and pathogen detection.
The flexible x-ray detector technology was then extended to demonstrate the viability of a new technique to seamlessly combine multiple smaller flexible x-ray detectors into a single very large, ultimately human sized, composite x-ray detector for new medical imaging applications such as single-exposure, low-dose, full-body digital radiography. Also explored, is a new approach to increase the sensitivity of digital x-ray detectors by selectively disabling rows in the active matrix array that are not part of the imaged region. It was then shown how high-resolution, flexible, organic light-emitting diode display (OLED) technology can be used to selectively stimulate and/or silence small groups of neurons on the cortical surface or within the deep brain as a potential new tool to diagnose and treat, as well as understand, neurological diseases and conditions. This work also explored the viability of a new miniaturized high sensitivity fluorescence measurement-based lab-on-a-chip optical biosensor using OLED display and a-Si:H PiN photodiode active matrix array technology for point-of-care diagnosis of multiple disease or pathogen biomarkers in a low cost disposable configuration.
The flexible x-ray detector technology was then extended to demonstrate the viability of a new technique to seamlessly combine multiple smaller flexible x-ray detectors into a single very large, ultimately human sized, composite x-ray detector for new medical imaging applications such as single-exposure, low-dose, full-body digital radiography. Also explored, is a new approach to increase the sensitivity of digital x-ray detectors by selectively disabling rows in the active matrix array that are not part of the imaged region. It was then shown how high-resolution, flexible, organic light-emitting diode display (OLED) technology can be used to selectively stimulate and/or silence small groups of neurons on the cortical surface or within the deep brain as a potential new tool to diagnose and treat, as well as understand, neurological diseases and conditions. This work also explored the viability of a new miniaturized high sensitivity fluorescence measurement-based lab-on-a-chip optical biosensor using OLED display and a-Si:H PiN photodiode active matrix array technology for point-of-care diagnosis of multiple disease or pathogen biomarkers in a low cost disposable configuration.
ContributorsSmith, Joseph T. (Author) / Allee, David (Thesis advisor) / Goryll, Michael (Committee member) / Kozicki, Michael (Committee member) / Blain Christen, Jennifer (Committee member) / Couture, Aaron (Committee member) / Arizona State University (Publisher)
Created2014
Description
This case study explores American Indian student activist efforts to protect and promote American Indian education rights that took place during 2007-2008 at a predominantly white institution (PWI) which utilizes an American Indian tribal name as its institutional athletic nickname. Focusing on the experiences of five American Indian student activists, with supplementary testimony from three former university administrators, I explore the contextual factors that led to activism and what they wanted from the institution, how their activism influenced their academic achievement and long-term goals, how the institution and surrounding media (re)framed and (re)interpreted their resistance efforts, and, ultimately, what the university's response to student protest conveys about its commitment to American Indian students and their communities. Data was gathered over a seven-year period (2007-2014) and includes in-depth interviews, participant observation, and archival research. Using Tribal Critical Race Theory and Agenda Setting Theory, this study offers a theoretically informed empirical analysis of educational persistence for American Indian students in an under-analyzed geographic region of the U.S. and extends discussions of race, racism, and the mis/representation and mis/treatment of American Indians in contemporary society.
Findings suggest the university's response significantly impacted the retention and enrollment of its American Indian students. Although a majority of the student activists reported feeling isolated or pushed out by the institution, they did not let this deter them from engaging in other social justice oriented efforts and remained dedicated to the pursuit of social justice and/or the protection of American Indian education rights long after they left the in institution. Students exercised agency and demonstrated personal resilience when, upon realizing the university environment was not malleable, responsive, or conducive to their concerns, they left to advocate for justice struggles elsewhere. Unfortunately for some, the university's strong resistance to their efforts caused some to exit the institution before they had completed their degree.
Findings suggest the university's response significantly impacted the retention and enrollment of its American Indian students. Although a majority of the student activists reported feeling isolated or pushed out by the institution, they did not let this deter them from engaging in other social justice oriented efforts and remained dedicated to the pursuit of social justice and/or the protection of American Indian education rights long after they left the in institution. Students exercised agency and demonstrated personal resilience when, upon realizing the university environment was not malleable, responsive, or conducive to their concerns, they left to advocate for justice struggles elsewhere. Unfortunately for some, the university's strong resistance to their efforts caused some to exit the institution before they had completed their degree.
ContributorsSolyom, Jessica A (Author) / Brayboy, Bryan (Thesis advisor) / Romero, Mary (Committee member) / Lee, Charles (Committee member) / Flores, Lisa (Committee member) / Arizona State University (Publisher)
Created2014
Description
The ability to monitor electrophysiological signals from the sentient brain is requisite to decipher its enormously complex workings and initiate remedial solutions for the vast amount of neurologically-based disorders. Despite immense advancements in creating a variety of instruments to record signals from the brain, the translation of such neurorecording instrumentation to real clinical domains places heavy demands on their safety and reliability, both of which are not entirely portrayed by presently existing implantable recording solutions. In an attempt to lower these barriers, alternative wireless radar backscattering techniques are proposed to render the technical burdens of the implant chip to entirely passive neurorecording processes that transpire in the absence of formal integrated power sources or powering schemes along with any active circuitry. These radar-like wireless backscattering mechanisms are used to conceive of fully passive neurorecording operations of an implantable microsystem. The fully passive device potentially manifests inherent advantages over current wireless implantable and wired recording systems: negligible heat dissipation to reduce risks of brain tissue damage and minimal circuitry for long term reliability as a chronic implant. Fully passive neurorecording operations are realized via intrinsic nonlinear mixing properties of the varactor diode. These mixing and recording operations are directly activated by wirelessly interrogating the fully passive device with a microwave carrier signal. This fundamental carrier signal, acquired by the implant antenna, mixes through the varactor diode along with the internal targeted neuropotential brain signals to produce higher frequency harmonics containing the targeted neuropotential signals. These harmonics are backscattered wirelessly to the external interrogator that retrieves and recovers the original neuropotential brain signal. The passive approach removes the need for internal power sources and may alleviate heat trauma and reliability issues that limit practical implementation of existing implantable neurorecorders.
ContributorsSchwerdt, Helen N (Author) / Chae, Junseok (Thesis advisor) / Miranda, Félix A. (Committee member) / Phillips, Stephen (Committee member) / Towe, Bruce C (Committee member) / Balanis, Constantine A (Committee member) / Frakes, David (Committee member) / Arizona State University (Publisher)
Created2014
Description
During attempted fixation, the eyes are not still but continue to produce so called "fixational eye movements", which include microsaccades, drift, and tremor. Microsaccades are thought to help prevent and restore vision loss during fixation, and to correct fixation errors, but how they contribute to these functions remains a matter of debate. This dissertation presents the results of four experiments conducted to address current controversies concerning the role of microsaccades in visibility and oculomotor control.
The first two experiments set out to correlate microsaccade production with the visibility of foveal and peripheral targets of varied spatial frequencies, during attempted fixation. The results indicate that microsaccades restore the visibility of both peripheral targets and targets presented entirely within the fovea, as a function of their spatial frequency characteristics.
The last two experiments set out to determine the role of microsaccades and drifts on the correction of gaze-position errors due to blinks in human and non-human primates, and to characterize microsaccades forming square-wave jerks (SWJs) in non-human primates. The results showed that microsaccades, but not drifts, correct gaze-position errors due to blinks, and that SWJ production and dynamic properties are equivalent in human and non-human primates.
These combined findings suggest that microsaccades, like saccades, serve multiple and non-exclusive functional roles in vision and oculomotor control, as opposed to having a single specialized function.
The first two experiments set out to correlate microsaccade production with the visibility of foveal and peripheral targets of varied spatial frequencies, during attempted fixation. The results indicate that microsaccades restore the visibility of both peripheral targets and targets presented entirely within the fovea, as a function of their spatial frequency characteristics.
The last two experiments set out to determine the role of microsaccades and drifts on the correction of gaze-position errors due to blinks in human and non-human primates, and to characterize microsaccades forming square-wave jerks (SWJs) in non-human primates. The results showed that microsaccades, but not drifts, correct gaze-position errors due to blinks, and that SWJ production and dynamic properties are equivalent in human and non-human primates.
These combined findings suggest that microsaccades, like saccades, serve multiple and non-exclusive functional roles in vision and oculomotor control, as opposed to having a single specialized function.
ContributorsCostela, Francisco M (Author) / Crook, Sharon M (Committee member) / Martinez-Conde, Susana (Committee member) / Macknik, Stephen L. (Committee member) / Baer, Stephen (Committee member) / McCamy, Michael B (Committee member) / Arizona State University (Publisher)
Created2014
Description
This study investigates the relationships between ESL teachers' beliefs about writing instruction and their use of computer technology in the first-year composition classroom. Utilizing a sociocultural approach, the study analyzes the connections between ESL teachers' instructional beliefs and the technological practices that emerge as a result of these beliefs and decisions. Qualitative research was conducted, and data was collected through classroom observations, teacher interviews, and course materials. Data analysis reveals that regardless of teachers' differing beliefs about writing instruction, they use computer technology when it enhances their teaching and students' learning. It also reveals that factors such as teacher attitude toward technology and adequate training affect the extent to which they incorporate technology into class.
ContributorsErdem, Ebru (Author) / Gelderen, Elly van (Thesis advisor) / Nilsen, Don (Committee member) / James, Mark (Committee member) / Arizona State University (Publisher)
Created2014
Description
Historically, institutions of higher education focused their efforts on programs and services to support traditional students' integration (i.e., the eighteen year old who enrolls in college immediately after graduating from high school) into the college environment. Integration into the university environment contributes to student retention. Underrepresented students, specifically community college transfer students, are left out of the retention planning process. With the increase of transfer students transitioning to four-year universities, this study explored transfer students' integration experience within their initial six weeks of attendance at a receiving institution. This action research study implemented an E-Mentoring Program utilizing the social media platform, Facebook. Results from the mixed-methods study provided evidence that classroom connection interwoven with social rapport with peers, cognizance of new environment, and institutional and peer resources matter for integration within the first six weeks at HUC (a pseudonym). The information gained will be used to inform higher education administrators, student affairs practitioners, faculty, and staff as they develop relevant services, programs, and practices that intentionally support transfer students' integration.
ContributorsAska, Cassandra (Author) / Puckett, Kathleen (Thesis advisor) / Kleinsasser, Robert (Committee member) / Cook, Kevin (Committee member) / Arizona State University (Publisher)
Created2015
Description
Cigarette smoking remains a major global public health issue. This is partially due to the chronic and relapsing nature of tobacco use, which contributes to the approximately 90% quit attempt failure rate. The recent rise in mobile technologies has led to an increased ability to frequently measure smoking behaviors and related constructs over time, i.e., obtain intensive longitudinal data (ILD). Dynamical systems modeling and system identification methods from engineering offer a means to leverage ILD in order to better model dynamic smoking behaviors. In this dissertation, two sets of dynamical systems models are estimated using ILD from a smoking cessation clinical trial: one set describes cessation as a craving-mediated process; a second set was reverse-engineered and describes a psychological self-regulation process in which smoking activity regulates craving levels. The estimated expressions suggest that self-regulation more accurately describes cessation behavior change, and that the psychological self-regulator resembles a proportional-with-filter controller. In contrast to current clinical practice, adaptive smoking cessation interventions seek to personalize cessation treatment over time. An intervention of this nature generally reflects a control system with feedback and feedforward components, suggesting its design could benefit from a control systems engineering perspective. An adaptive intervention is designed in this dissertation in the form of a Hybrid Model Predictive Control (HMPC) decision algorithm. This algorithm assigns counseling, bupropion, and nicotine lozenges each day to promote tracking of target smoking and craving levels. Demonstrated through a diverse series of simulations, this HMPC-based intervention can aid a successful cessation attempt. Objective function weights and three-degree-of-freedom tuning parameters can be sensibly selected to achieve intervention performance goals despite strict clinical and operational constraints. Such tuning largely affects the rate at which peak bupropion and lozenge dosages are assigned; total post-quit smoking levels, craving offset, and other performance metrics are consequently affected. Overall, the interconnected nature of the smoking and craving controlled variables facilitate the controller's robust decision-making capabilities, even despite the presence of noise or plant-model mismatch. Altogether, this dissertation lays the conceptual and computational groundwork for future efforts to utilize engineering concepts to further study smoking behaviors and to optimize smoking cessation interventions.
ContributorsTimms, Kevin Patrick (Author) / Rivera, Daniel E (Thesis advisor) / Frakes, David (Committee member) / Nielsen, David R (Committee member) / Arizona State University (Publisher)
Created2014
Description
Biogenic silica nanostructures, derived from diatoms, possess highly ordered porous hierarchical nanostructures and afford flexibility in design in large part due to the availability of a great variety of shapes, sizes, and symmetries. These advantages have been exploited for study of transport phenomena of ions and molecules towards the goal of developing ultrasensitive and selective filters and biosensors. Diatom frustules give researchers many inspiration and ideas for the design and production of novel nanostructured materials. In this doctoral research will focus on the following three aspects of biogenic silica: 1) Using diatom frustule as protein sensor. 2) Using diatom nanostructures as template to fabricate nano metal materials. 3) Using diatom nanostructures to fabricate hybrid platform.
Nanoscale confinement biogenetic silica template-based electrical biosensor assay offers the user the ability to detect and quantify the biomolecules. Diatoms have been demonstrated as part of a sensor. The sensor works on the principle of electrochemical impedance spectroscopy. When specific protein biomarkers from a test sample bind to corresponding antibodies conjugated to the surface of the gold surface at the base of each nanowell, a perturbation of electrical double layer occurs resulting in a change in the impedance.
Diatoms are also a new source of inspiration for the design and fabrication of nanostructured materials. Template-directed deposition within cylindrical nanopores of a porous membrane represents an attractive and reproducible approach for preparing metal nanopatterns or nanorods of a variety of aspect ratios. The nanopatterns fabricated from diatom have the potential of the metal-enhanced fluorescence to detect dye-conjugated molecules.
Another approach presents a platform integrating biogenic silica nanostructures with micromachined silicon substrates in a micro
ano hybrid device. In this study, one can take advantages of the unique properties of a marine diatom that exhibits nanopores on the order of 40 nm in diameter and a hierarchical structure. This device can be used to several applications, such as nano particles separation and detection. This platform is also a good substrate to study cell growth that one can observe the reaction of cell growing on the nanostructure of frustule.
Nanoscale confinement biogenetic silica template-based electrical biosensor assay offers the user the ability to detect and quantify the biomolecules. Diatoms have been demonstrated as part of a sensor. The sensor works on the principle of electrochemical impedance spectroscopy. When specific protein biomarkers from a test sample bind to corresponding antibodies conjugated to the surface of the gold surface at the base of each nanowell, a perturbation of electrical double layer occurs resulting in a change in the impedance.
Diatoms are also a new source of inspiration for the design and fabrication of nanostructured materials. Template-directed deposition within cylindrical nanopores of a porous membrane represents an attractive and reproducible approach for preparing metal nanopatterns or nanorods of a variety of aspect ratios. The nanopatterns fabricated from diatom have the potential of the metal-enhanced fluorescence to detect dye-conjugated molecules.
Another approach presents a platform integrating biogenic silica nanostructures with micromachined silicon substrates in a micro
ano hybrid device. In this study, one can take advantages of the unique properties of a marine diatom that exhibits nanopores on the order of 40 nm in diameter and a hierarchical structure. This device can be used to several applications, such as nano particles separation and detection. This platform is also a good substrate to study cell growth that one can observe the reaction of cell growing on the nanostructure of frustule.
ContributorsLin, Kai-Chun (Author) / Ramakrishna, B.L. (Thesis advisor) / Goryll, Michael (Thesis advisor) / Dey, Sandwip (Committee member) / Prasad, Shalini (Committee member) / Arizona State University (Publisher)
Created2014
Description
This study reviews the effectiveness of a faculty development program to prepare faculty members in the health related fields to design and develop flipped and blended learning courses. The FAB Tech workshop focuses on flipped and blended learning technologies as a method to increase the use of active learning in the classroom. A pre/posttest was administered to the participants on their use of technology and their course delivery strategies. In addition, interviews were conducted with a purposeful sample of the participants based on level of engagement in the workshop and their change in the pre/posttest. The program was effective in increasing the use of technological tools and their purposeful integration into courses. However, faculty workload and institutional support issue served as barriers to overcome. The findings of this study will help address how to over come some of these barriers and to develop more effective faculty development programs that encourage the use of flipped and blended learning.
ContributorsCrawford, Steven Raymond (Author) / Puckett, Kathleen (Thesis advisor) / Mathur, Sarup (Committee member) / Vaughn, Linda (Committee member) / Arizona State University (Publisher)
Created2015
Description
Stroke is a leading cause of disability with varying effects across stroke survivors necessitating comprehensive approaches to rehabilitation. Interactive neurorehabilitation (INR) systems represent promising technological solutions that can provide an array of sensing, feedback and analysis tools which hold the potential to maximize clinical therapy as well as extend therapy to the home. Currently, there are a variety of approaches to INR design, which coupled with minimal large-scale clinical data, has led to a lack of cohesion in INR design. INR design presents an inherently complex space as these systems have multiple users including stroke survivors, therapists and designers, each with their own user experience needs. This dissertation proposes that comprehensive INR design, which can address this complex user space, requires and benefits from the application of interdisciplinary research that spans motor learning and interactive learning. A methodology for integrated and iterative design approaches to INR task experience, assessment, hardware, software and interactive training protocol design is proposed within the comprehensive example of design and implementation of a mixed reality rehabilitation system for minimally supervised environments. This system was tested with eight stroke survivors who showed promising results in both functional and movement quality improvement. The results of testing the system with stroke survivors as well as observing user experiences will be presented along with suggested improvements to the proposed design methodology. This integrative design methodology is proposed to have benefit for not only comprehensive INR design but also complex interactive system design in general.
ContributorsBaran, Michael (Author) / Rikakis, Thanassis (Thesis advisor) / Olson, Loren (Thesis advisor) / Wolf, Steven L. (Committee member) / Ingalls, Todd (Committee member) / Arizona State University (Publisher)
Created2014