University of Illinois Urbana-Champaign
Illinois Digital Environment for Access to Learning and Scholarship RepositoryNot a member yet
123813 research outputs found
Sort by
Tensile strength and elastic modulus of tall fescue (Lolium arundinaceum) grass roots
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01The student, Kayla Wall, accepted the attached license on 2025-07-25 at 13:31.The student, Kayla Wall, submitted this Thesis for approval on 2025-07-25 at 13:46.This Thesis was approved for publication on 2025-07-25 at 14:48.DSpace SAF Submission Ingestion Package generated from Vireo submission #22740 on 2025-10-21 at 10:06:24This thesis presents the sample collection, testing methods, and results of tensile strength testing for laboratory-grown tall fescue (Lolium arundinaceum) for comparison with existing tensile strength and modulus data for Lolium arundinaceum from other studies. Lolium arundinaceum plants were grown and fertilized in temperature- and light-controlled growing chambers in both confined growing tubes on a level surface and in boxes constructed at a 3 horizontal to 1 vertical (3H:1V; or 18.4-degree) slope. Seventy-three tensile strength measurements and 52 elastic modulus values for Lolium arundinaceum roots less than 0.5 millimeters in diameter collected during this research were compared with 97 tensile strengths and 94 modulus measurements for Lolium arundinaceum grass root diameters ranging from 0.45 to 2.30 millimeters obtained from literature. Tensile strength and elastic modulus were found to increase with decreasing diameter, represented as a power law regression trendline. Coefficients of determination (R2) for the power-law regression trendlines from this testing program were improved for tensile strength (from 0.66 to 0.82) and for modulus values (0.59 to 0.76) after including data from the literature
The impact of trauma exposure on post-traumatic growth among Iraqi refugees: Examining the moderating roles of social support and hope
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01The student, Hameed Makttoof, accepted the attached license on 2025-05-07 at 17:14.The student, Hameed Makttoof, submitted this Dissertation for approval on 2025-05-07 at 17:39.This Dissertation was approved for publication on 2025-05-15 at 09:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #22260 on 2025-10-25 at 15:30:42This study examined the relation between trauma exposure and psychological adjustment among Iraqi refugees in the United States. Drawing from a sample of 93 adult Iraqi refugee participants in the U.S. completed self-report measures assessing trauma exposure, social support, hope, post-traumatic growth, and psychological well-being. Hierarchical multiple regression analyses were used to assess whether perceived social support and hope moderated the relation between trauma and adjustment outcomes. Findings indicated that both social support and hope moderated the association between trauma and post-traumatic growth, but only in the context of low trauma. However, in predicting psychological well-being, only trauma emerged as a significant predictor; neither hope nor social support were significant predictors, and they did not moderate the association between trauma and well-being. These findings suggest that while hope and social support were central to fostering growth following trauma, psychological well-being may be more directly influenced by the severity of trauma exposure. This research contributes to the growing literature on refugee mental health by highlighting the distinct pathways through which trauma influences psychological outcomes. Limitations and future directions of the research are discussed
A novel floating cultivation platform to boost crop yield and improve water quality
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01The student, Youheng Fan, accepted the attached license on 2025-07-10 at 10:45.The student, Youheng Fan, submitted this Dissertation for approval on 2025-07-10 at 10:45.This Dissertation was approved for publication on 2025-07-18 at 06:19.DSpace SAF Submission Ingestion Package generated from Vireo submission #22482 on 2025-10-25 at 15:30:57The objective of this study was to develop a novel floating bed system, utilizing nutrition in polluted pools and lakes to grow valuable crops and vegetables. The system is powered by solar energy and can be applied to cultivate numerous cash crops using a floating platform on a water body like a pond or lake. The research questions that this study attempted to answer are: 1) Is the nutrition in polluted ponds receiving agricultural runoff enough to support plant growth? 2) Can proper water flow increase the nutrient uptake by the plant root, which can enhance plant biomass? 3) Can the solar energy absorbed by solar panels be used to generate water flow, promoting nutrient uptake by the plant roots? 4) Can we cultivate crops on water bodies like ponds with high nutrient levels without the need for additional fertilizers? To answer those questions, an indoor validation experiment was conducted based on a hydroponic system, with different flow rates set in the pipelines to observe the final biomass of the vegetables. A fluid model was used to calculate to ensure that the solar-powered propeller generates sufficient flow speed near the plant roots. And outdoor field experiments were conducted in a pond that received agricultural runoff to cultivate crops. The results from this study indicate that (1) plant biomass can be increased by more than 10% based on proper water flow, and (2) an on-water planting system with a solar-driven propeller can generate enough water flow around the plant root area to increase the plant biomass significantly. Thus, the novel floating bed system can be implemented for application in the treatment of agricultural pollution in water bodies
Van der Waals magnetic materials for spintronic device applications
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01The student, Stasiu Chyczewski, accepted the attached license on 2025-07-17 at 18:01.The student, Stasiu Chyczewski, submitted this Dissertation for approval on 2025-07-17 at 18:19.This Dissertation was approved for publication on 2025-07-17 at 20:39.DSpace SAF Submission Ingestion Package generated from Vireo submission #22647 on 2025-10-25 at 15:31:04Layered van der Waals (vdW) materials have attracted great attention for both their unique physical properties and potential applications in advanced devices. 2D magnets represent a new and rapidly growing family of materials that are being studied for spintronics. In addition to ferromagnets, non-magnetic 2D materials with strong spin orbit coupling and exotic symmetry also hold promise. In the first chapter I will briefly discuss magnetic devices in general, including the history and current state of the art. I will also introduce 2D magnetic materials, with an emphasis on the iron germanium/gallium telluride (FGT) family. In the second chapter I will introduce experimental work using electrical transport to systematically characterize 2D magnets. This includes the use of magnetotransport to unveil competing magnetic phases in iron germanium telluride as shown by the material's temperature dependent transport properties, planar Hall response, and field cooling divergence. The third chapter will entail a discussion of magnetic proximity effects observed in vdW heterostructures. Results showing how iron germanium telluride/platinum heterostructures exhibited unexpected emergent behavior will be presented. This includes changes such as wider hysteresis, steeper reversal, and larger magnetoresistance. The fourth chapter will present a study of MoTe2 films grown using MOCVD for spin orbit torque applications. We demonstrate highly efficient spin-charge conversion in wafer scale 1T' films grown in a back-end-of-line (BEOL) compatible process. The last chapter focuses on 2D multiferroics. I will present efforts to realize an artificial vdW multiferroic comprised of discrete ferromagnetic and ferroelectric components as well as discussions on the design considerations of such structures. I will also introduce results of a study of heterostructures incorporating the intrinsic vdW multiferroic NiI2 and graphene. These structures allow for the electrical characterization of the otherwise insulating helimagnet NiI2
Ranking features used in modeling student collaboration using multimodal learning analytics
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Robin Jephthah Rajarathinam, accepted the attached license on 2025-05-09 at 10:44.The student, Robin Jephthah Rajarathinam, submitted this Dissertation for approval on 2025-05-09 at 11:07.This Dissertation was approved for publication on 2025-05-13 at 14:50.DSpace SAF Submission Ingestion Package generated from Vireo submission #22283 on 2025-10-25 at 15:52:18This dissertation tackles a persistent challenge in computer-supported collaborative learning (CSCL): how to identify the behavioral signals that matter most for detecting productive peer interaction in noisy, face-to-face classrooms. Drawing on the fourth design cycle of the NSF-funded CSTEPS project, the study asks (a) how individual data streams—video, audio, log traces, and speech transcripts—characterize specific collaborative behaviors, (b) whether fusing those streams improves machine classification, and (c) which fine-grained features contribute most to accurate prediction. By ranking features across modalities, the work aims to guide researchers and learning-technology designers in selecting sensors and analytics that yield the greatest instructional value. A quasi-experimental field study captured 31 undergraduate engineering groups over seven weeks (53 students wore head-mounted microphones, generating 34 multimodal sessions) during tablet-mediated problem-solving discussions. After synchronizing video, individual audio, shared-tablet logs, and automatic transcripts, hundreds of prosodic, linguistic, visual, and interaction features were extracted. Feature space was reduced through correlation filtering, PCA, and recursive feature elimination, then modeled with six classical classifiers (decision tree, random forest, SVM, AdaBoost, XGBoost, Naïve Bayes). A five-fold group-level cross-validation protocol, augmented by SMOTE to counter class imbalance, ensured generalization to unseen groups. Unimodal baselines were followed by early- and late-fusion multimodal models. Unimodal models confirmed complementary strengths: log interaction ratios best signaled On Task engagement (balanced accuracy = 0.84) while audio prosody captured OffTopicTalk and ToolTalk. Early fusion raised balanced accuracy for most codes (e.g., 0.84 for On Task), but late fusion delivered the most consistent gains, peaking at 0.90 balanced accuracy and 0.93 F1 for On Task, with moderate improvements for cognitively demanding behaviors such as MetaCognition and BuildingIdeas. Feature-importance analysis revealed that (i) loudness and pitch slopes were dominant audio cues for unstructured off-task dialogue, (ii) sentiment-laden textual n-grams differentiated idea-building talk, (iii) gaze minima and cheek-raiser action units flagged explanations, and (iv) scroll-balance ratios in the whiteboard log robustly indexed group engagement. Methodologically, the study offers a tested pipeline—group-wise cross-validation, targeted SMOTE, and decision-level fusion—for researchers modeling small-group collaboration at scale. Theoretically, it demonstrates that multimodal signals are synergistic rather than redundant: preserving modality-specific classifiers before aggregation yields the most balanced view of complex behaviors. Practically, the ranked feature set pinpoints a lean, interpretable subset (e.g., loudness variance, gaze convergence, scrolling equality) that can power real-time teacher dashboards without excessive sensor overhead. Future work should extend adaptive fusion strategies and leverage emerging 360° video and unobtrusive audio wearables to boost data fidelity and ecological validity
Investigating the impact of colonic bacteroides intestinalis-mediated wheat arabinoxylan degradation on lipid metabolism and inflammation modulation
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Ziyu Zhou, accepted the attached license on 2025-05-14 at 10:58.The student, Ziyu Zhou, submitted this Thesis for approval on 2025-05-14 at 12:38.This Thesis was approved for publication on 2025-07-18 at 15:20.DSpace SAF Submission Ingestion Package generated from Vireo submission #22299 on 2025-10-25 at 15:52:27Inflammatory bowel diseases (IBD), including Crohn’s disease and ulcerative colitis, are chronic gastrointestinal inflammation driven by genetic factors, immune dysregulation, environmental influences, and gut microbiota. Arabinoxylan, which is one type of dietary fiber commonly present in cereals, consists primarily of xylose chains substituted with arabinofuranose and ferulic acid residues. Bacteroides intestinalis (BI) is a strain of colonic bacteria plays a crucial role in metabolizing arabinoxylan through specialized gene clusters termed polysaccharide utilization loci (PULs). These PULs enable BI to efficiently degrade arabinoxylan, releasing bioactive metabolites including ferulic acid, which is known for its antioxidant and anti-inflammatory properties. This research investigated the combined effects of dietary insoluble wheat arabinoxylan (INWAX) supplementation and Bacteroides intestinalis colonization in germ-free mouse models of colitis. Results indicate that this combination significantly increased systemic ferulic acid levels, enhanced bile acid production, and reduced oxidative stress levels. In a DSS-induced colitis model, mice receiving both INWAX and BI exhibited reduced inflammation, mitigated spleen enlargement and preserved intestinal morphologies. RNA sequencing analyses revealed INWAX diet induced upregulation in genes associated with circadian rhythm regulation, lipid and carbohydrate metabolism, and antioxidant responses. Additionally, RNA sequencing and immune cell fraction analysis of DSS-treated spleen indicated increased adaptive immune responses coupled with reduced spleen size with INWAX diet, suggesting more efficient inflammation control. Overall, these findings highlight the therapeutic potential of integrating dietary insoluble wheat arabinoxylan with Bacteroides intestinalis colonization to manage intestinal inflammation. Future research could explore deeper mechanisms, including examining microbial metabolites, their broader implications in gut health and inflammatory regulation, and their possible interactions with differential gene expressions
Two heads are better than one: Investigating the benefits of interaction in collaborative decision making
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Belgin Unal, accepted the attached license on 2025-05-29 at 13:08.The student, Belgin Unal, submitted this Dissertation for approval on 2025-05-29 at 14:11.This Dissertation was approved for publication on 2025-05-30 at 09:51.DSpace SAF Submission Ingestion Package generated from Vireo submission #22314 on 2025-10-25 at 15:52:30Groups often outperform individuals in cognitive tasks. However, there is little consensus on the cognitive mechanisms that underlie effective teamwork. The present investigation examines whether the process of group interaction plays a critical role in enhancing collective performance. In the first three experiments, participants answered general knowledge questions either in pairs that were allowed to discuss and collaborate, or individually. Individual responses were used to construct nominal groups using a range of established aggregation policies. In all cases, interacting groups consistently outperformed all nominal group variants, suggesting that the advantages of group cognition stem not only from the increased knowledge pool, but from the interactive process itself. A fourth experiment extended this approach to the domain of misinformation detection—an area of pressing real-world concern—revealing a more complex pattern and pointing to potential limits in the generalizability of interaction benefits across task domains. These findings demonstrate the importance of fostering interaction in collaborative settings, where shared reasoning and metacognitive exchange can significantly improve collective decision-making
Unraveling sorghum stem biology through organ-specific and cell-type-specific transcriptomic analyses across development
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Jie Fu, accepted the attached license on 2025-06-24 at 09:46.The student, Jie Fu, submitted this Dissertation for approval on 2025-06-24 at 10:06.This Dissertation was approved for publication on 2025-06-25 at 15:52.DSpace SAF Submission Ingestion Package generated from Vireo submission #22359 on 2025-10-25 at 15:52:34Sorghum bicolor is a promising bioenergy crop due to its high biomass yield, resilience to environmental stress, and low nutrient requirement. However, a comprehensive molecular understanding of sorghum stem development and cell-type specialization remains limited, hindering targeted improvement of biomass quality and carbon allocation. This dissertation presents a multi-scale, transcriptome-centered approach to investigate sorghum stem biology at both organ and cell-type resolution across key developmental stages. Chapter 1 provides a detailed introduction to sorghum as an important feedstock, its stem structure and development, and current knowledge gaps and obstacles for “ideotype” development, laying the foundation for targeted investigation. Chapter 2 leverages public transcriptomic datasets to identify organ-specific expression patterns and uncover a set of stem-preferred/specific genes and their dynamic expression pattern across developmental stages. Motif enrichment and functional analyses highlight candidate regulatory elements and gene functions associated with stem identity. In Chapter 3, laser capture microdissection (LCM) was used to isolate five anatomically distinct cell types from the sorghum stem, enabling high-resolution transcriptomic profiling. This analysis reveals spatially organized metabolic and regulatory programs, cell-type-specific gene networks, and elucidates distinct cellular mechanisms for secondary cell wall formation. Chapter 4 integrates transcriptomic and proteomic analyses of stem cell types before and after floral initiation to explore developmental reprogramming. The results uncover a tradeoff between secondary cell wall biosynthesis and non-structural sugar accumulation and highlight the dynamic regulation of key biosynthetic pathways during the transition to reproductive growth. Together, these studies offer a systems-level view of sorghum stem biology, providing new insight into stem cell-type function, developmental programming, and regulatory network. The findings lay the groundwork for precision engineering of stem traits to optimize sorghum as a bioenergy feedstock
The Native new wave: creative sovereignty in twenty-first century Indigenous genre fiction
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Cyanne Topaum, accepted the attached license on 2025-06-24 at 16:17.The student, Cyanne Topaum, submitted this Dissertation for approval on 2025-06-24 at 16:26.This Dissertation was approved for publication on 2025-06-25 at 15:00.DSpace SAF Submission Ingestion Package generated from Vireo submission #22362 on 2025-10-25 at 15:52:50My dissertation, “The Native New Wave: Creative Sovereignty in Twenty-First Century Indigenous Genre Fiction,” argues that Indigenous genre writers transform the tropes and conventions of the genres they work in through creative reinscription. I focus on how these acts of tropological transformation make generic conventions into a vehicle to express a political commitment to Indigenous communities. While previous scholarship has often emphasized the “subversive” aspects of Native genre writing, my dissertation reads the current “Native New Wave” as genre enthusiasts who wish for their work to be legible as horror, crime fiction, and speculative fiction to their respective audiences. Chapter 2 focuses on Stephen Graham Jones’s slasher fiction and argues that Jones reimagines the “slasher killer” and “final girl” archetypes while chapter 3 discusses Native crime writers such as Carole laFavor, Marcie R. Rendon, and Angeline Boulley and examines how they use the genre’s individualization of criminality to critique settler vigilantism. In chapter 4, I contend that the postapocalyptic novels of Cherie Dimaline and Waubgeshig Rice use the deaths of Indigenous characters to critique Native ressentiment, identities produced in reaction to settler colonialism. Dimaline, Rice, and Louise Erdrich additionally reinscribe Lee Edelman’s “The Child” to signify as an Indigenous refusal to die. Chapter 5 focuses on the zombie narratives of Morgan Talty, Stephen Graham Jones, and Jeff Barnaby and how each of these creators engage with the generic legacy of George A. Romero. Across multiple genres, writers of the “Native New Wave” demonstrate that the meaning of inherited tropes and conventions is not fixed or static, but capable of reinvention
Roles of origin recognition complex subunit 6 (Orc6) in DNA replication and damage response
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-08-01The student, Dazhen Liu, accepted the attached license on 2025-07-09 at 20:11.The student, Dazhen Liu, submitted this Dissertation for approval on 2025-07-09 at 20:13.This Dissertation was approved for publication on 2025-07-15 at 15:10.DSpace SAF Submission Ingestion Package generated from Vireo submission #22406 on 2025-10-25 at 15:52:58Well-regulated replication and timely repair of DNA is required for genome stability maintenance, and failing to do so leads to tumorigenesis. This thesis will focus on how human Orc6, the smallest subunit of Origin Recognition Complex (ORC) which shows dispensable role in origin licensing, functions in DNA replication progression and regulates chromatin remodeler binding. In Chapter 1, I review the following three aspects: 1) protein complexes involved in DNA replication licensing and initiation, represented by ORC; 2) DNA damage response regulated by ATM/ATR-signaling; 3) ATP-dependent chromatin remodeling complexes and their association with DNA replication or repair. In Chapter 2, I investigate the functional relevance of Orc6-T229 phosphorylation in replication fork progression and cancer cell migration & invasion. Orc6-pT229 is an S-phase-specific, oxidative damage-triggered and ATR-dependent modification. I further confirm that Orc6-pT229 localizes at replication forks and reduces fork progression rate. Cell cycle progression upon release from oxidative damage is impacted with the presence of the Orc6-T229 phosphomimic mutant. I therefore propose that Orc6-pT229 is a replication fork pausing signal. Further, I showed that Orc6-pT229 as a signal of tumor suppression since it was lacking from colorectal cancer tissue, and the phosphomimic mutant reduced the tumorigenic behaviors (such as migration and invasion) of cancer cell lines. A pan-cancer analysis further revealed the high Orc6 expressions in various cancers. In Chapter 3, I further investigate the role of Orc6 upon oxidative damage. The genomic binding of Orc6 was characterized using CUT&RUN method, and I found that Orc6 was enriched at open chromatin regions and at active replication origins. Oxidative damage leads to a more widespread genomic binding of Orc6. Interestingly, I noticed that Orc6, but not other ORC components, shows potential of association with high-molecular-weight, non-ORC protein complexes. With proteomic method, I identified and characterized the S-phase specific, oxidative damage-triggered interaction between Orc6 and ISWI family chromatin remodeler SMARCA1. Genomic mapping of SMARCA1 showed that when Orc6 is depleted, SMARCA1 binds to original Orc6-enriched sites, and this causes an increase of local chromatin accessibility. Low Orc6 presence also facilitates the remodeling of SMARCA1, while increased Orc6 presence may negatively regulate it. The chromatin remodeling at Orc6-depleted sites could correlate with local DNA damage, active replication fork/origin remodeling or dormant origin firing, which requires further investigation. Finally, in Chapter 4, I concluded my work in Chapters 2 & 3 and discussed the gaps in knowledge and limitations of the work. Meanwhile, I discussed some connections between these two chapters