University of Illinois Urbana-Champaign
Illinois Digital Environment for Access to Learning and Scholarship RepositoryNot a member yet
123813 research outputs found
Sort by
Electromagnetic, thermal, hydraulic and mechanical characterization of frozen soils having different initial thermal and hydraulic properties
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Anshu Abhinav, accepted the attached license on 2025-03-12 at 19:25.The student, Anshu Abhinav, submitted this Dissertation for approval on 2025-03-12 at 19:32.This Dissertation was approved for publication on 2025-03-18 at 14:35.DSpace SAF Submission Ingestion Package generated from Vireo submission #21663 on 2025-10-19 at 19:52:28This research focuses on the investigation of the coupled electromagnetic, thermal, hydraulic, and mechanical properties of frozen geomaterials subjected to thermal gradients. Accelerated subsurface warming in the cold regions exacerbates the temporal and spatial evolution of frozen ground properties which necessitates the accurate characterization of frozen geomaterials. Existing studies often focus on isolated external effects, such as thermal conductivity or mechanical strength under frozen conditions at constant temperatures, without considering the complex interdependencies between these properties. Therefore, the main objective of this research is to investigate the coupled relationships between thermal, electromagnetic, and hydraulic properties of frozen soils under varying temperatures and their impact on the mechanical properties. Laboratory experiments were conducted using capacitance sensors and Electrical Impedance Spectroscopy to characterize the effect of initial degree of saturation, initial dry density, temperature, and applied frequency on the bulk electromagnetic properties - specifically dielectric constant and electrical conductivity - of sand, silt, and clay soils. The dielectric permittivity values from the measurements were used to calibrate the physics-based models for estimating the water content and ice content of soils at different temperatures below 0°C. The estimated water contents were plotted against temperature to establish soil freezing curves. A set of laboratory experiments were performed to characterize the thermal properties of soils during the freezing and thawing process and a new methodology for measuring ice content during freezing and thawing was introduced. The latent heat during the phase change of water was quantified and used to predict the ice content. The results from the latent heat calculations were consistent with ice contents estimated from the capacitance experiments. Direct simple shear tests were performed at temperatures below 0°C on soil samples having initial degrees of saturation identical to the soil samples prepared for previous experiments. This allowed for an in-depth evaluation of how ice content, as indicated by the soil freezing curves, influences the shear strength of frozen soils. The results from this study demonstrated the significant impact of initial degree of saturation, temperature, and soil type on the thermal, hydraulic, electromagnetic, and mechanical properties of frozen soils. An increase in the initial degree of saturation resulted in a higher dielectric permittivity, electrical conductivity, latent heat, ice content, and the shear strength at temperatures below 0°C. Decreases in soil temperature initiated the phase change and it resulted in decreasing dielectric permittivity, electrical conductivity, and a significant increase in the shear strength. A further decrease in the temperature continued to increase the shear strength of frozen soil due to an increase in ice content as expected. For the same initial water contents, clay and silt soils exhibited lower ice contents, but higher shear strengths compared to the sand. Based on the results of shear strength tests, an integrated failure criteria using Mohr-Coulomb model and soil freezing curve was developed for frozen sand. The approach followed in this research is an important step towards advancing our understanding of how the coupled effects of thermal gradients, initial degree of saturation, and soil type influence the electromagnetic, thermal, hydraulic, and mechanical properties of frozen soils under thermal gradients. By providing a detailed characterization of the frozen soil properties, more accurate predictions of soil behavior under changing environmental conditions can be achieved. The results from this research contribute to long-term sustainability by enhancing the ability to assess and mitigate the impact of changes in climate trends on frozen soil stability, ultimately supporting more resilient infrastructure development in the Arctic and cold regions
The perceptions of virtual members of project meetings about sharing work-related knowledge with other members
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Sadia Mazid, accepted the attached license on 2025-04-16 at 14:03.The student, Sadia Mazid, submitted this Dissertation for approval on 2025-04-16 at 14:04.This Dissertation was approved for publication on 2025-04-18 at 12:28.DSpace SAF Submission Ingestion Package generated from Vireo submission #21774 on 2025-10-19 at 19:52:53Knowledge sharing is widely acknowledged as a critical driver of individual performance, team collaboration, and organizational innovation. While the dynamics of knowledge sharing have been extensively studied in traditional work settings, its enactment in virtual contexts remains insufficiently explored—particularly in light of the rapid global transition to remote and hybrid work models accelerated by the COVID-19 pandemic. As organizations increasingly rely on geographically dispersed project teams, digital transformation and globalization have introduced new modes of collaboration that conventional frameworks fail to adequately address. This qualitative study investigates the perceptions of project team members regarding their experiences with sharing work-related knowledge during virtual meetings. Specifically, it explores four interrelated areas: (1) perceptions of participating in virtual meetings, (2) perceptions of knowledge sharing during these meetings, (3) reflections on the outcomes of sharing knowledge remotely, and (4) challenges encountered in virtual knowledge-sharing processes. Drawing on an interpretive description methodology, the study engaged twelve professionals from diverse industries through semi-structured interviews and critical incident techniques. Thematic analysis framework has used to identify recurrent patterns in participant narratives. Seven major themes emerged from the data: adapting to new ways of doing work; understanding the virtual meeting context; using the right technology in the right situations; making sure all members participate; growing connections so others know about me; communicating with cross-cultural team members; and managing emotions in virtual environments. These themes reveal that knowledge sharing in virtual settings is shaped not only by the technological tools used but also by gender, social, cultural, and emotional factors. Participants emphasized that while digital platforms such as Zoom, Teams, and Slack facilitate remote collaboration, meaningful knowledge exchange also depends on trust, psychological safety, and the ability to build and sustain interpersonal relationships. The study makes significant contributions to Human Resource Development (HRD) theory by underscoring the need for socially grounded frameworks that address the relational dimensions of knowledge sharing. It challenges the overemphasis on digital infrastructure by highlighting the importance of informal communication, social capital, and cultural sensitivity in virtual knowledge environments. Practically, the findings offer actionable insights for HRD practitioners and organizational leaders. Recommendations include implementing resilience-building programs to support employees’ adaptability, designing inclusive virtual cultures that encourage participation across diverse teams, and fostering Virtual Communities of Practice (VCoPs) to enable informal, cross-functional collaboration. Future research should examine how social capital is cultivated and sustained in virtual contexts, particularly within multicultural and geographically dispersed teams. Additionally, further inquiry is needed into the mechanisms by which digital platforms can support relational networks and promote sustained, high-quality knowledge exchange in remote work environments
Ghostdecoding: leveraging random-feature kernels for error-aware and training-free KV cache selection
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Hao Guo, accepted the attached license on 2025-04-22 at 00:56.The student, Hao Guo, submitted this Thesis for approval on 2025-04-22 at 01:04.This Thesis was approved for publication on 2025-04-22 at 15:40.DSpace SAF Submission Ingestion Package generated from Vireo submission #21877 on 2025-10-19 at 19:53:35Key-value (KV) cache is essential for efficient inference in large language models (LLMs) by storing intermediate representations to reduce redundant computations. However, as sequence lengths grow, it becomes a major bottleneck due to increasing computational and memory demands. Existing KV cache compression methods mitigate this issue by pruning or selecting critical entries, but often suffer from several limitations, including unpredictable errors, limited dynamism, and strong assumptions about context relevance. In this work, we propose GhostDecoding, a novel training-free KV cache selection mechanism that dynamically reduces the effective sequence length while maintaining error awareness for evicted entries. Using a random feature softmax kernel, our method estimates the attention score of an arbitrary number of evicted positions with O(1) time and space overhead, and selectively recomputes them when necessary. We develop efficient sparse CUDA kernels to support our algorithm. Experimental results demonstrate that GhostDecoding achieves up to 1.6× more computation reduction compared to H2O, leading to up to 1.9× decoding speed-up compared to full attention on long sequences
Thin-film flows and soft hydraulics with complex fluids for environmental and microfluidic-based applications
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Sunggyu Chun, accepted the attached license on 2025-04-22 at 13:57.The student, Sunggyu Chun, submitted this Dissertation for approval on 2025-04-23 at 12:07.This Dissertation was approved for publication on 2025-04-28 at 15:05.DSpace SAF Submission Ingestion Package generated from Vireo submission #21885 on 2025-10-19 at 19:53:36A wide range of practical fluids, such as polymer solutions, colloidal suspensions, foams, and biologically relevant fluids, show non-Newtonian behaviors in engineering applications. Unlike their Newtonian counterparts, these fluids exhibit complex nonlinear responses to deformation and shear stress. In particular, non-Newtonian fluid flows in confined geometries are ubiquitous across natural and engineered systems and across scientific disciplines, ranging from enhanced oil recovery to geophysical problems, to polymer and materials processing, to biomicrofluidics and organs-on-chips, to flexible and wearable electronics. However, the interplay between fluid rheology and geometrical confinement presents intricate challenges to understand and manipulate the fluid behaviors. Here, to address this research frontier, my PhD dissertation is dedicated to advancing the fundamental understanding of non-Newtonian fluid flows in confined geometry considering two canonical configurations, with a combination of experimental and theoretical methodologies. The first configuration involves thin-film flows, where a confined bubble propagates through non-Newtonian fluids, influencing the deposition of liquid films and bubble morphologies. The second configuration focuses on fluid-structure interactions in soft hydraulic systems, where the interplay between complex fluid rheology and structural compliance governs the flow behavior. By bridging experimental findings with theoretical frameworks, this dissertation advances the fundamental understanding of non Newtonian fluid mechanics in both thin film flows and soft hydraulics. These insights may provide valuable engineering guidance for controlling flows in porous media, optimizing coating processing, enhancing design of biomedical devices, microfluidic systems as well as soft robotics. In the first part of the dissertation, the motion of an elongated bubble within a confined geometry filled with non Newtonian fluids is explored through both experimental and theoretical approaches. While the dynamics of film deposition in Newtonian fluids is well understood, the behavior of complex non-Newtonian fluids remains elusive, especially in the development of predictive scaling laws for film thickness. In this dissertation, I systematically investigate the influence of shear-thinning viscosity and viscoelasticity on thin film deposition, bubble velocity, and bubble shape formation. Building upon the recent advancements in hydrodynamic theory, scaling laws are derived to capture the intricate interplay between complex fluid rheology and interfacial dynamics, incorporating dimensionless parameters such as the capillary number, Carreau number, and Weissenberg number. The theoretical scaling laws for the film thicknss are in good agreement with experimental observations across a wide range of experimental parameters. In addition, a high degree of undulations on the bubble surface results in an intricate rear viscosity distribution for the rear meniscus and the deviation between the experiments and theory may require a further investigation to resolve the axial velocity field. In the second part of the dissertation regarding soft hydraulics, while low Reynolds number flows of Newtonian fluids through rigid and compliant conduits are well-characterized, it is not the case for non-Newtonian fluids, where complex rheology interacts with wall compliance in a nontrivial manner. Even for steady, low-Reynolds-number flows, a complete understanding of how viscoelasticity and shear-dependent viscosity influence the flow rate–pressure drop relation in deformable configurations remains an open challenge. To systematically investigate the interplay between fluid rheology and wall compliance, I establish an experimental framework to obtain high precision experimental data on the flow rate–pressure drop relationship in two canonical deformable systems: a rectangular channel with a top deformable wall and an axisymmetric tube. By introducing key dimensionless parameters. i.e. the Carreau, Deborah, and compliance numbers, to describe fluid rheology and wall compliance, I demonstrate good agreement between theoretical predictions and experimental measurements for the flow rate–pressure drop relations in steady shear-thinning and purely viscoelastic fluids flows
Combatting pathogens through directed evolution, single-cell sequencing, and synthetic immunology
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Stanley Bram, accepted the attached license on 2025-04-22 at 11:23.The student, Stanley Bram, submitted this Dissertation for approval on 2025-04-22 at 11:35.This Dissertation was approved for publication on 2025-04-29 at 18:44.DSpace SAF Submission Ingestion Package generated from Vireo submission #21887 on 2025-10-19 at 19:53:37This thesis explores three innovative applications of directed evolution methodologies for pathogen control, each addressing distinct challenges in therapeutic development. Foremost, I created a novel B cell-based evolution platform for therapeutic antibody development by engineering a synthetic regulatory system that mimics natural somatic hypermutation mechanisms. Through clustered regularly interspaced short palindromic repeat (CRISPR) mediated integration of composite regulatory elements, including the IgHV4-34 promoter and intronic enhancer, I established a cell-type specific system capable of directing controlled genetic variation. This platform demonstrates potential not only for antibody engineering but also for broader applications in protein evolution. Second, in collaboration with the United States Department of Agriculture (USDA), I developed enhanced methods for analyzing the porcine immune response to influenza infection through single-cell sequencing of B cell repertoires. This work established comprehensive protocols for isolating and characterizing complete antibody sequences from individual B cells, enabling high resolution analysis of the immunoglobulin repertoire. While this approach provides unprecedented insight into viral evolution and host immunity, throughput and cost considerations currently constrain its application to population-scale surveillance. However, the foundations provided in this work serve as a starting point to streamline functional, personalized RNA-sequencing methods. Third, I engineered the UDP-galactose 4-epimerase (GalE) system in E. coli to utilize synthetic nicotinamide adenine dinucleotide (NAD+) analogs, establishing a platform for vaccine development through controlled bacterial attenuation. Through directed evolution, I successfully generated enzyme variants capable of utilizing the synthetic cofactor nicotinamide isoquinolinone dinucleotide (NQD+) demonstrating altered cofactor specificity in vitro. While biochemical characterization revealed promising catalytic properties, challenges in cellular uptake, cofactor stability, and enzyme half-life currently limit in vivo implementation. Yet still, the establishment of synthetic, orthogonal cofactor redox systems in this work provides a starting point for further optimization, which, when sufficiently resolved, may result in ‘switchable’ chemistries of life that have not yet been explored throughout the evolution of organisms. Together, these approaches demonstrate the versatility of directed evolution in addressing contemporary challenges in vaccine and therapeutic development, while highlighting the importance of considering both molecular and cellular contexts in engineering biological systems. Future work will focus on overcoming identified technical barriers and expanding these platforms for broader therapeutic applications
Roots and wings: Empowering translanguaging pedagogy with Chinese American bilingual community teachers
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Jiadi Zhang, accepted the attached license on 2025-04-22 at 12:11.The student, Jiadi Zhang, submitted this Dissertation for approval on 2025-04-22 at 12:20.This Dissertation was approved for publication on 2025-04-23 at 09:11.DSpace SAF Submission Ingestion Package generated from Vireo submission #21888 on 2025-10-19 at 19:53:38This dissertation examines two Chinese American bilingual teachers' translanguaging pedagogy within two Mandarin Language Arts classrooms in a community school. Drawing on a three-year ethnographic study in a Chinese Bilingual Community School, the research addresses two primary questions: 1) How do the two Chinese American bilingual teachers articulate and enact their translanguaging stance in a community school? And 2) How do two Chinese American bilingual teachers’ interactions with students and parents inform their translanguaging pedagogy? Through classroom observation, semi-structured interviews, and artifact analysis, the study documents the evolving practices of Ning and Summer—two Chinese American bilingual teachers—who leveraged their personal and professional experiences and close connections with the community they serve to inform their translanguaging pedagogy with Chinese American bilingual students. The findings reveal that translanguaging stances grow out of teachers’ transnational lived experiences, professional experiences, and critical understanding of their Chinese American students’ translanguaging needs. Moreover, teachers’ translanguaging pedagogy was continuously refined through interactions with multiple stakeholders in the community school. Students’ challenges and critiques led teachers to critically reflect and refine their translanguaging design; parents recognized as co-educators, played a crucial role in scaffolding Chinese American bilinguals’ translanguaging practices in and outside of the classroom. By expanding conceptualizations of translanguaging beyond the classroom and foregrounding community engagement, this study contributes to bilingual and biliteracy education and teacher education in bi/multilingual settings by offering ideological, pedagogical, and theoretical insights on translanguaging for teachers, teacher educators, and researchers
Document-based and oral histories of Diné experiences in the Mormon Indian Student Placement Program, 1945-2000
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, M. Nathan Tanner, accepted the attached license on 2025-04-29 at 11:33.The student, M. Nathan Tanner, submitted this Dissertation for approval on 2025-04-29 at 11:45.This Dissertation was approved for publication on 2025-04-30 at 14:34.DSpace SAF Submission Ingestion Package generated from Vireo submission #22047 on 2025-10-19 at 19:54:33This study is a historical investigation of Diné/Navajo experiences in the Mormon Indian Student Placement Program, or what constituted an educational ecology both influenced by and that actively shaped the economic, political, and social institutions, ideologies, and pedagogies of the post-World War II era. Relying on available archival records, government reports, legal documents, periodicals, books and articles, private papers, and oral histories from survivors, this study exposes one of the largest systematic Native child removal projects in modern US history. Between 1945 and 2000, The Church of Jesus Christ of Latter-day Saints—otherwise known as the Mormons, or LDS—colluded with federal and state bureaucrats to remove, relocate, and school tens of thousands of Indigenous children and youth in white Mormon foster families’ homes and in predominantly white and Mormon public schools. Importantly, oral testimonies of Diné who experienced the Placement Program help narrate this history and reveal Diné survivance—the combination of resistance and survival—of attempts to eliminate their culture, language, and traditional beliefs. The Mormons’ Indian education programming, while seemingly a new approach to schooling Native youth in the late-twentieth century, shared continuity with, and reproduced the genocidal education approaches of the infamous federal Indian boarding school system. At its height in the 1970s, the Placement Program was a transcontinental and transnational education program that operated in twenty-three U.S. States and three Canadian Provinces. By the year 2000, children aged six to eighteen from at least 75 tribal nations were involved. Between 48,000 to 62,000 children are estimated to have been enrolled in the Mormons’ Placement Program; the overwhelming majority, though, were Diné/Navajo. Approximately one in twelve of all Diné citizens were enrolled sometime during the program’s operation, or approximately 8-10% of the entire population of Navajo Nation. This human tithe on the Navajo Nation allowed the Mormons to capitalize off Native child removal, racialized Native communities, and propagated the American settler colonial project. This history illuminates the ongoing struggle for self-determined and sovereign Indigenous education, as well as the enduring power and survivance of Diné through k’é
CNNFORMER interpolation: a demosaicing framework for single-chip color–NIR1 imaging in fluorescence-guided cancer surgery
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Jiankun Yang, accepted the attached license on 2025-05-05 at 11:45.The student, Jiankun Yang, submitted this Thesis for approval on 2025-05-05 at 11:54.This Thesis was approved for publication on 2025-05-09 at 10:56.DSpace SAF Submission Ingestion Package generated from Vireo submission #22098 on 2025-10-19 at 19:54:44Single-chip multispectral imaging sensors that integrate vertically stacked photodiodes with pixelated spectral filters offer significant promise for advanced, real-time visualization during image-guided cancer surgery. However, the inherent design trade-offs of these sensors lead to a substantial reduction in spatial resolution, which can limit their clinical utility. Conventional demosaicing algorithms, such as bilinear interpolation and convolutional neural network (CNN)-based approaches, have been developed to mitigate these limitations by improving the effective resolution and reducing common image artifacts. While these methods have achieved meaningful improvements, they still exhibit deficiencies in accuracy and often introduce smaller, yet clinically relevant, reconstruction artifacts, particularly in regions with high spatial frequency content. To address these persistent challenges, this work presents a CNN–Transformer-based demosaicing algorithm specifically optimized for reconstructing high-resolution color and near-infrared (NIR) images acquired by a hexachromatic multispectral imaging sensor. Transformer architectures, originally developed for natural language processing to capture long-range dependencies within sequential data, have recently shown remarkable success when adapted to vision tasks due to their ability to model complex, global relationships across an image. By integrating convolutional layers for local feature extraction with Transformer modules for capturing long-range context, the proposed hybrid model was developed and trained on extensive color-image datasets and rigorously evaluated on both color and NIR imagery. Quantitative evaluation demonstrates that the CNN–Transformer demosaicing method achieves an average mean squared error (MSE) reduction of approximately 85% for color images and 76% for NIR images, along with improvements in structural dissimilarity (DSSIM) of roughly 72% and 79%, respectively, when compared to state-of-the-art CNN-based demosaicing algorithms on preclinical datasets. In clinical datasets, the model similarly achieves significant reductions in MSE and DSSIM, particularly excelling at reconstructing fine image details critical for accurate intraoperative visualization. These results underscore the capability of Transformer-based models to surpass the limitations of traditional CNN-only approaches by capturing more comprehensive spatial information. Leveraging recent advances in GPU computing, the proposed CNN–Transformer demosaicing framework offers a practical, real-time solution for enhancing spatial resolution and image fidelity in multispectral imaging applications, ultimately advancing the effectiveness of image-guided cancer surgery
Learning-oriented accountability: Facilitators and constraints to organizational learning in a local nonprofit funding system
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Hope Holland, accepted the attached license on 2025-05-01 at 10:43.The student, Hope Holland, submitted this Dissertation for approval on 2025-05-01 at 10:56.This Dissertation was approved for publication on 2025-05-02 at 11:27.DSpace SAF Submission Ingestion Package generated from Vireo submission #22149 on 2025-10-19 at 19:55:38Over the past three decades, funding entities increased nonprofit performance measurement-related grant components under the assumption that nonprofits, service users, and funding agencies alike would benefit from nonprofit organizations’ increased accountability. Research indicates that nonprofits devote substantial time and resources to funder-imposed reporting, often at the expense of client-facing services. Yet, critics suggest that bureaucratically driven, compliance-focused activities rarely contribute to organizational learning or service enhancement. Some research suggests that more collaborative funder-grantee relationships could enhance organizational learning and efficiency within accountability relationships. The significance of this study lies in its exploration of the formal and informal accountability context between a local funding agency and its nonprofit grantees, a relatively underrepresented topic in the existing literature. Using qualitative interview data with funding agency and nonprofit grantee representatives, this paper examines the ways in which a funding organization may facilitate and constrain learning-oriented accountability within the interorganizational system. The current study finds that respondents most frequently attributed successful learning-oriented accountability within the system to interpersonal factors within the inter-organizational institutional environment, with particular attention to supportive and invested funding agency leadership, approachable and accessible funding staff, and compassionate, non-punitive problem-solving approaches. Respondents also described constraints, primarily defined by unrealistic expectations and competing priorities compounded by already limited agency resources (e.g., time and staff). Respondents also noted deficient feedback practices, particularly from funding stakeholders to nonprofit agency stakeholders. This study enhances our understanding of organizational behavior within the nonprofit sector and contributes to the broader academic discourse on accountability and learning in inter-organizational settings. Furthermore, it offers suggestions for funding agencies aiming to foster a practice of learning and accountability in their interactions with grantees
The impact of alpha-tocopherol status on brain polyunsaturated fatty acid composition and oxidative stress
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-05-01The student, Harper Sutton, accepted the attached license on 2025-05-02 at 10:55.The student, Harper Sutton, submitted this Thesis for approval on 2025-05-02 at 11:08.This Thesis was approved for publication on 2025-05-06 at 16:28.DSpace SAF Submission Ingestion Package generated from Vireo submission #22177 on 2025-10-19 at 19:55:41α-Tocopherol (αT) is a lipophilic antioxidant that prevents lipid peroxidation by donating its phenolic hydrogen to peroxyl radicals. Its antioxidant capacity is particularly important for neurological functioning, and many studies have been conducted to evaluate the role of αT in neuroprotection and cognitive functioning. Polyunsaturated fatty acids (PUFAs) are highly abundant in the brain, and are especially susceptible to lipid peroxidation, which can cause significant damage to cell membranes and promote cell death. Lipid peroxidation in the nervous system is linked to neurodegenerative disease, cancer, and other neurological disorders. Adequate αT status is essential to prevent the propagation of lipid peroxidation and protect brain PUFAs. This thesis focuses on alpha tocopherol (αT) primarily due to its preferential incorporation into very low density lipoproteins (VLDL) for extrahepatic distribution by the αtocopherol transfer protein (α-TTP). α-TTP is expressed in the liver and brain, which suggests an essentiality of αT for proper functioning of the nervous system. We utilized the α-TTP knockout (Ttpa-/-) mouse model to study vitamin E deficiency. It is difficult to create vitamin E deficiency using wild-type mice, as vitamin E has a long half-life, making it challenging to deplete tissues, especially the brain. Ttpa-/- mice have very low tissue levels of αT (outside of the liver), which makes them a suitable model for extrahepatic vitamin E deficiency. This model has been well characterized in older mice, where oxidative stress and cognitive decline are common, however, the optimization of the model for younger mice is less developed. Previous work in this lab has explored the use of a lipopolysaccharide challenge to induce inflammation to assess oxidative stress in Ttpa-/- mice, as innate oxidative stress isn’t as ii abundant in younger mice. These studies have not yielded significant genotype differences in measures of oxidative stress and inflammation, which necessitates the exploration of additional endpoints related to oxidative stress to better characterize the model. This thesis primarily focuses on the impact of αT status on polyunsaturated fatty acid composition in the cerebral cortices of both Ttpa-/- and wild-type mice (Chapter 2). A secondary objective of this thesis is to determine the period of αT depletion necessary to observe significant reductions in brain PUFA concentrations compared to αT-sufficient mice. We hypothesized that mice fed an αT-deficient diet would have lower concentrations of PUFAs in the cerebral cortex compared to mice fed an αT-sufficient diet, and that these effects would be more pronounced in Ttpa-/- mice. We also anticipated that a longer period of αT deficiency would exacerbate these reductions in PUFA concentrations. Our research revealed that mice fed an αT-deficient diet had lower cortical PUFA concentrations compared to αT-sufficient mice, and that these effects were more pronounced after 12 weeks of αT depletion. Surprisingly, Ttpa-/- mice did not have lower PUFA levels compared to wild-type mice, and in fact, for some PUFAs, concentrations were lower for wild-type mice. Additional research is necessary to better understand the mechanisms by which αTdeficiency leads to a reduction in cortical PUFA concentrations, and also to explore the impact of supplementation following depletion on oxidative stress and brain PUFA composition. This work furthers our understanding of the Ttpa-/- mouse model and also αT’s role as an antioxidant