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QUANTIFYING ASSOCIATIONS OF PER- AND POLYFLUOROALKYL SUBSTANCES (PFASs) IN SERUM WITH DRINKING WATER SOURCE AND FUNCTIONAL MEASURES OF IMMUNOTOXICITY
No full textThesis (Ph.D.)--Michigan State University. Pharmacology and Toxicology-Environmental Toxicology - Doctor of Philosophy, 2025Per- and polyfluoroalkyl substances (PFASs) are synthetic chemicals widely used in consumer products for their stain- and water-resistant properties. These substances are known for their persistence in the environment and in the human body, leading to widespread contamination and increasing concerns about their potential health effects. PFAS have been linked to reproductive, developmental, liver, kidney, and immune effects. In 2018, high levels of PFAS (1600 ng/L) were discovered in the municipal wells of a small community in southwestern Michigan, linked to an abandoned paper mill and landfill. In 2020-2021, we conducted a detailed exposure assessment in this community. We examined the mixture of PFAS from this paper mill source in drinking water and its persistence in human serum. Serum was collected from 100 participants and analyzed for 35 PFASs using LC-MS/MS. Approximately half of the study participants had private wells with lower PFAS concentrations (55ug/L) serum PFAS concentrations. Whole blood was collected to determine white blood cell counts. Peripheral blood mononuclear cells were isolated and stained for flow cytometry under unstimulated and stimulated conditions to quantify cytotoxic and helper T cell subsets and markers of T cell activation. Supernatants from stimulated cells were analyzed for interleukin-2 using ELISA. We observed that elevated serum PFAS concentrations were associated with alterations in the percentages of neutrophils, lymphocytes, na\uefve cytotoxic T cells, and T cell activation, suggesting PFAS exposure may disrupt T cell homeostasis and contribute to immune dysregulation. Overall, this dissertation provides critical insights into the long-term persistence of PFAS exposure in a contaminated community and the potential immunotoxic effects.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Transportation Vibration Effects on Apple Bruising
Get PDFThesis (M.S.)--Michigan State University. Packaging - Master of Science, 2025Mechanical damage, particularly bruising, is a major cause of postharvest losses in fresh produce, significantly impacting fruit quality and marketability. Apples, being highly susceptible, experience external forces during handling, storage, and transportation, primarily from vibrations, impacts, and compression. This study analyzes the effects of vibration parameters (intensity and duration), truck suspension systems, apple varieties, and packaging configurations on minimizing apple bruising under realistic transportation conditions. Two apple varieties, Fuji and Jonagold, were packaged in corrugated boxes with trays, reusable plastic containers (RPCs) with trays, and volume packing systems. They were exposed to random vibration profiles based on ASTM D4169, simulating leaf-spring and air-ride suspensions at intensities 0.2, 0.3, 0.5 and 0.7 Gravity Root Mean Square (Grms) for 1, 3, and 5 hours. Additionally, a multi-layer packaging setup was tested to evaluate damage distribution across layers. Results demonstrated that vibration intensity, duration, and suspension type significantly influence bruising. Leaf-spring suspensions caused more damage than air-ride systems, especially at higher intensities and longer durations. Apples in the top layer of stacked packages experienced the most damage, while lower layers benefited from load distribution. Among packaging types, corrugated board with Hexcel wrap outperformed others, offering improved protection and recyclability. To further assess factor importance, Random Forest Regression was applied, revealing vibration intensity as the most influential factor, followed by duration, packaging type, and apple variety. These findings support the need for optimized packaging and vibration control strategies. This study highlights the importance of combining vibration testing, sustainable packaging materials, and multi-layer designs to reduce apple bruising. It also suggests the development of new ASTM/ISTA test profiles tailored to produce distribution, including multi-axis vibration testing for improved simulation accuracy.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
CREATING ZINES, CONSTRUCTING PLACE : PLACE-MAKING AND COMMUNITY-BUILDING PRACTICES OF ZINE MAKERS
Get PDFThesis (M.A.)--Michigan State University. Rhetoric and Writing \u2013 Master of Arts, 2025This thesis explores the value of zines as multimodal texts that can create a sense of space, place, and/or community for both zine readers and zine-makers (\u201czinesters\u201d). In this thesis, I discuss the contributions of space and place to the production of, engagement with, and preservation of zines within communities. After reviewing literature on the archival, pedagogical, rhetorical, and methodological implications of zines, I interview three zinesters \u2013 Remi Germaine, Bre Upton, and Alice Wynne \u2013 and pose a series of questions about their zine-making processes and conceptions of space, place, and community. I respond to the same questions as a fourth and final case study, then collate, summarize, and expand on my takeaways in the form of a \u201csummative zine,\u201d included in the appendix of this thesis. By analyzing and assigning descriptive themes to the interview responses, I identify and explore five key takeaways in the summative zine: among them, the capacity of zines to fight sterility, facilitate placemaking through provenance, and function as rhetorical infrastructures for personal and communal expression.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
MULTI-DIMENSIONAL INVESTIGATIONS INTO THE BIOMECHANICS OF THE HUMAN THUMB : A FOCUS ON OSTEOARTHRITIS AND SURGERY
No full textThesis (Ph.D.)--Michigan State University. Mechanical Engineering - Doctor of Philosophy, 2025The human thumb is necessary for the completion of daily tasks (e.g., driving, cooking), and accounts for 40% of overall hand function. However, the carpometacarpal (CMC) joint, located at the base of the thumb, has developed osteoarthritis (OA) in up to 50% of older individuals, with a preponderance among females. The associated symptoms of pain, weakness, and deformity have led to the inability to perform self-care, depression, and considerable financial burdens. Therefore, there is a pressing need to monitor the health and function of the thumb joints to track the onset, progression, and treatment of CMC OA. In cases of severe CMC OA, surgical intervention has been pursued. Numerous surgical techniques have been used to treat CMC OA, and have been effective in reducing patient pain. However, patients have reported dissatisfaction with thumb function after surgery, and currently there are limited approaches to compare post-operative outcomes across various interventions. Clinical tools are not able to capture the complex and dynamic abilities of the thumb, including its full range of motion and ability to generate force. Thus, there is a need for approaches to assess and monitor complete three-dimensional thumb motions and changes in force generation. This dissertation presents work in these areas. Chapter one is a review of the literature, and discusses thumb anatomy and its unique characteristics. The prevalence, impact, and treatment of CMC OA are identified. Chapter two discusses the methods used to quantify motion of the thumb metacarpal using motion capture marker-derived coordinate systems on the hand dorsum. Results showed statistically and clinically significant differences in angle ranges and errors between coordinate systems, highlighting the importance of careful coordinate system selection. Chapter three studies the kinematics of the thumb metacarpal and proximal phalange using a two-dimensional motion mapping in asymptomatic controls and CMC OA participants (tested pre-surgery, 3-month, and 6-months post-surgery) that received surgery. Results suggested that surgery reduced participant pain, but did not return motion abilities to those of controls. Further, control females had significantly greater proximal phalange motion, indicating it could be related to the onset of CMC OA. Chapter four details the creation and utilization of a novel three-dimensional analysis (termed the \u2018thumb kinematic space\u2019) of the cohorts tested in Chapter three. Quantitative and visual changes in kinematic spaces were examined. After surgery, thumb kinematic space volume was significantly reduced, did not return to those of controls, and deformity persisted. Chapter five discusses thumb metacarpal internal/external rotation, and its coupling with other joint rotations. An unexpected result was acquired, and internal/external rotation was observed before and after surgery when the CMC joint was damaged or partially removed, indicating muscle action as the primary driver of rotation. Chapter six presents the construction and use of a novel device to measure forces of the thumb in various postures independently of other fingers. Significant differences in force magnitudes suggested that standard clinical tools are insufficient. Chapter seven is an analysis of the location and direction of thumb force application, which are important factors for task completion. Control and participants with CMC OA showed similar locations and direction, which were primarily in the operative space of the thumb for daily tasks. Chapter eight is an overview of this work, its impact, and potential future expansion.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Value-Added Carbon Fiber Reinforced Composites from Post-Consumer Poly (ethylene terephthalate) Bottles and Thermoform
Get PDFThesis (M.S.)--Michigan State University. Packaging - Master of Science, 2025Poly (ethylene terephthalate) (PET) is widely used in packaging plastics and accounts for up to 26% of all plastics used in packaging in the U.S. The challenges with PET recycling that must be addressed to promote the PET circular economy incorporate the existence of thermoformed PET (PET-T) in PET bottle (PET-B) recycled bales and the purification of PET to remove contaminants for food contact applications, among others. The aim of this research was to develop potential value-added composites for non-food applications made of PET-B and PET-T. As reported in this thesis, carbon fiber-reinforced composites prepared from postconsumer PET T and PET-B blends were assessed. In total, three different carbon fiber lengths of 0.5, 1, and 2 inches and two different carbon fiber loadings of 1 and 3 wt.% were used in PET-T and PET-B blends, where PET-T was 20 wt.% and PET-B was 80 wt.%. These composites were prepared in the presence and absence of epoxy chain extenders. The mechanical properties of the obtained composites were evaluated with tests including measurements of their tensile strength, modulus of elasticity, impact strength, and percentage elongation at break. In addition, heat deflection temperature, glass transition temperature, melting temperatures, degree of crystallinity, and thermal degradation were also tested. Furthermore, SEM analyses were performed to assess fiber distribution and adhesion between polymer and fiber. Our results showed that recycled PET-B/PET-T carbon fiber-reinforced composites at 3 wt.% fiber loading had up to a 20% increase in tensile strength, up to a 50% increase in modulus of elasticity, and up to an 18% increase in impact strength compared to recycled PET-B/PET-T without carbon fiber. In addition, recycled PET-B/PET-T carbon fiber-reinforced composites had significantly better mechanical properties than virgin polypropylene (PP) carbon fiber-reinforced composites at 3 wt.% carbon fiber loading, albeit with lower elongation at break than PP composites. Furthermore, carbon fiber-reinforced recycled PET-B/PET-T had similar properties to those of virgin PET carbon fiber-reinforced blends. Moreover, the heat deflection temperatures significantly increased in the recycled PET-B/PET-T carbon fiber-reinforced blends, making them suitable for automotive and other value-added composite applications. While further studies are needed to gain insights into the effects of higher loads of carbon fiber and the use of treated carbon fiber, the current findings suggest that recycled PET-B/PET-T carbon fiber-reinforced blends can be of potential value in composites. Implementing these findings in real-world applications can promote the plastic circular economy and mitigate carbon emissions by reducing reliance on virgin PET.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Agroforestry Extent around the Lake States Region : Novel Spatial Methods Combined with Survey Evidence to Analyze Agroforestry Adoption Across Michigan, Ohio, and Wisconsin, USA
No full textThesis (M.S.)--Michigan State University. Forestry - Master of Science, 2025This thesis examines the extent of agroforestry in Michigan, Ohio, and Wisconsin by combining high-resolution spatial analysis of linear woody features with landowner survey data. The primary aim is to document the prevalence of practices such as windbreaks and riparian forest buffers and to investigate the management intentions explaining their genesis. Convolutional neural networks (CNNs) were employed to create a sub-meter land cover product using US Department of Agriculture (USDA) National Agricultural Imagery Program (NAIP) imagery, and shape-based metrics were then used to detect the presence of linear small woody features. Validation and case studies in 35 counties indicate that this approach accurately pinpoints narrow tree lines in agricultural landscapes.Parallel survey work engaged landowners through a multi-wave mailing strategy. Participants described their use of woody features, offering details on motivations, management intensity, and plans for future tree establishment or maintenance. Results demonstrated alignment between survey-reported windbreaks and riparian forest buffers and the automated mapping outputs in many cases, though some discrepancies arose in parcels with fragmented ownership or minimal maintenance. The findings emphasize the significance of precise, high-resolution classification methods for quantifying agroforestry practices at scale. They also highlight how social and economic factors shape whether landowners consider these woody features essential to farm and forested systems. By integrating spatial and survey-based evidence, this thesis provides a fuller perspective on agroforestry extent and adoption in the Lake States and presents strategies to refine classification thresholds. The multi-layered methodology can inform regional policymakers, resource managers, and extension services seeking to recognize and support these beneficial tree-based practices.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Fresh Perspectives : How Journaling Develops Student Voices in First-Year Writing
Get PDFThesis (M.A.)--Michigan State University. Rhetoric and Writing \u2013 Master of Arts, 2025This thesis explores the role of journaling in first-year writing classroomsand its impact on the development of voice in student writing. Drawing from personal experience and academic research, this study examines how journaling can serve as a tool for fostering self-discovery, creativity, and a deeper understanding of the writing process. The research highlights perspectives from scholars such as Peter Elbow, Kathleen Blake Yancey, and Jacqueline Jones Royster on voice in writing as well as Toby Fulwiler and Lynda Barry on journaling as a pedagogical tool. The study also employs a qualitative research approach that analyzes student responses collected through surveys conducted before and after a semester-long journaling process in a first-year writing course. The findings suggest that students who engage in consistent journaling develop a strong connection to their writing and gain confidence in their writerly voice. The thesis concludes by discussing the broader implications of integrating journaling into writing pedagogy and offers suggestions for educators to emphasize journaling and student voice in their writing classes.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
NOVEL COMPUTATIONAL FRAMEWORKS FOR ANALYZING COMPLEX NON-TREE-LIKE EVOLUTION IN GENOMIC SEQUENCE DATA
No full textThesis (Ph.D.)--Michigan State University. Computer Science - Doctor of Philosophy, 2025Phylogenetics studies the evolutionary relationships among species, often represented as phylogenetictrees. However, traditional tree-like models fall short when dealing with interspecific gene flows, such as hybridization/introgression in eukaryotes and horizontal gene transfer (HGT) in prokaryotes, which necessitate the use of phylogenetic networks to capture complex, reticulate evolutionary histories. Although numerous methodologies have been developed to analyze nontree- like evolutions, the advent of high-throughput sequencing technologies has introduced two primary scalability challenges: the large number of taxa present in the data and the intricate and diverse gene flow among these taxa. These challenges have considerably constrained the scope and precision of non-tree-like phylogenetic inference and analysis. This dissertation addresses these limitations by introducing novel techniques for analyzing non-tree-like evolutions in large-scale genomic studies. We developed PHiMM, an introgression detection tool that combines coalescent-based approximations with hidden Markov models (HMMs) to improve scalability and detection accuracy. Comparisons with state-of-the-art methods on both simulation and empirical datasets indicated that PHiMM significantly outperforms previous methods like PhyloNet-HMM in terms of runtime and memory usage, while maintaining comparable inference accuracy to PhyloNet-HMM. To further enhance PHiMM\u2019s performance, we integrated it with the SERES resampling tool, significantly improving introgression inference accuracy under various model conditions. Simulation experiments demonstrated that combining the SERES resampling approach with PHiMM substantially improves introgression inference accuracy compared to standalone PHiMM, although it results in longer runtimes. One major limitation of PHiMM is its requirement for a phylogenetic network as input to constitute the structure of the HMM. To address this, we extended PHiMM to DACS by integrating phylogenetic network inference with introgression detection. To further improve the scalability and accuracy of introgression mapping on ultra large datasets, we adopted divide-and-conquer and subsampling techniques, allowing us to efficiently handle the complexity of the data while maintaining accuracy. Moreover, we applied these approaches to metagenomic studies, where data often include thousands of species derived from complex microbial communities. After assembling the sequencing reads into metagenome-assembled genomes (MAGs), we employ DACS to identify reticulate evolutionary events, such as introgression or HGT, under challenging scenarios characterized by noise, incomplete data, and large numbers of taxa. By adapting our methods to accommodate the scale and complexity of metagenomic datasets, we provide a powerful framework for elucidating reticulate evolutionary histories in diverse microbial communities. These advancements provide deeper insights into genetic and biological processes and offer robust tools for a wide range of biological and medical applications.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
ADAPTIVE MECHANISMS FOR METAL DETOXIFICATION BY ELECTROACTIVE BACTERIA
No full textThesis (Ph.D.)--Michigan State University. Microbiology - Environmental Toxicology - Doctor of Philosophy, 2025Metal contamination is a widespread environmental threat in great need of sustainable remediation strategies. Electroactive (electricity-producing) bacteria, particularly those in the order Geobacterales, are ubiquitous in these environments and drive metal transformations that limit their mobility and spread. Studying these bacteria thus affords opportunities to understand cellular mechanisms for enhanced detoxification and harness the knowledge in environmental clean-up and metal recovery applications. The unifying feature of the physiology of Geobacterales and close relatives in the Desulfuromonadia class is their ability to discharge respiratory electrons to metals. This allows them to respire metal minerals, particularly bioreducible ironIII oxide minerals abundant in the Earth\u2019s crust, from terrestrial soils and sediments to hot sediments near deep-sea hydrothermal vents. Their metal-reducing activities dissolve the minerals and release metal cations trapped in the solid phases, including metals of economic importance such as uranium, cobalt, and palladium. Despite the release of metal cations at concentrations toxic to most living organisms, Geobacterales grow in these environments and contribute to their reductive precipitation. The reductive dissolution of the ironIII oxides and the mineralization of solubilized metal cations require the assembly of conductive protein appendages (pili), which function as nanowires between the cell and the metals via electric discharges at dedicated surface motifs on the pili. This dissertation describes novel paths for enhanced metal detoxification in the laboratory representative Geobacter sulfurreducens and unique adaptations of the first described nanowire-producing, thermophilic relative, Geothermobacter ehrlichii, to metal cycling in deep-sea hydrothermal vents. Chapter 1 introduces the reader to the topic of metal contamination and the unique adaptive mechanisms used by Geobacterales and close relatives to detoxify toxic metals via their reductive mineralization by pilus nanowires. Chapter 2 describes gaps of knowledge in the field based on studies of uranium reduction in the model representative Geobacter sulfurreducens and identifies the cell\u2019s rough lipopolysaccharide (LPS) as an overlooked mechanism to enhance metal immobilization in this organism. This chapter also identifies outer membrane vesiculation as a pathway for the detoxification of the LPS-bound uranium that can substitute for the nanowire pathways under certain laboratory conditions. Chapter 3 further investigates the environmental signals that modulate vesiculation in G. sulfurreducens. The study revealed that subtle and easily overlooked differences in the ionic strength of media formulations, but also the presence of reducible metal cations such as the uranyl cation, influence cell wall structure and modulate the formation of outer membrane vesicles. These cation-mediated cell wall dynamics play a critical role in the selection of pathways for metal detoxification, showcasing the complementarity of nanowires and vesiculation. This work also underscores the importance of media formulations in the reproducibility of metal reduction phenotypes in Geobacterales and the translational power of the laboratory studies in field applications. Chapter 4 expands metal detoxification studies beyond Geobacterales and into the thermophilic relative G. ehrlichii. Sequencing and closure of its genome enabled identification of conserved metal detoxification pathways, including rough LPS and conductive pili. Comparison of the G. ehrlichii pilus subunit (pilin) with those of the Geobacterales relatives revealed structural similarities and differences in aromatic density (a hallmark of conductive peptides). Furthermore, analysis of reported values of pilus conductivity in these bacteria identified a strong correlation between pilin aromatic density and resistivity of the assembled pilus. Lastly, divergent features at the G. ehrlichii pilin carboxy-terminus are consistent with a metal trap evolved to immobilize trivalent metal cations such as rare earth elements, which are enriched in hydrothermal vent fluids. These results suggest that conductive pili are a widespread metal detoxification strategy in Desulfuromonadia but also identify divergent features reflecting ecological adaptations that could be harnessed to reclaim an expansive catalog of economically important metals. Future directions to achieve this are described in more detail in Chapter 5 along with the main conclusions of the experimental work reported in this dissertation.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Understanding Change in Students' Competence Beliefs : A Mixed Methods Study
Get PDFThesis (Ph.D.)--Michigan State University. Educational Psychology and Educational Technology - Doctor of Philosophy, 2025Recent calls in motivation research emphasize understanding motivation as a situative phenomenon that emerges through dynamic teacher-student interactions (Turner & Nolen, 2015). Competence-related beliefs are especially important for supporting students' effort, persistence, and learning in challenging subject areas like science. This mixed methods study examined whether and how competence-supportive instruction relates to students\u2019 competence beliefs during a science unit. The quantitative strand drew on survey data from 17 middle school science teachers and their students (n = 346) to identify potential sources of change in students\u2019 competence beliefs. Teachers\u2019 competence-supportive instruction positively predicted gains in students\u2019 competence beliefs over time, even after accounting for initial science interest and prior achievement, both of which were also significant predictors. Analyses also revealed distinct classroom-level patterns of change in students\u2019 competence beliefs, with some classrooms characterized by relatively uniform increases, others demonstrating relatively uniform decreases, and still others showing substantial individual variation. To further explore these classroom-specific patterns, the qualitative strand examined three classroom cases that focused on how teachers enacted competence-supportive strategies and how students\u2019 daily competence perceptions unfolded across multiple lessons. State-space grids (SSGs) embedded in each case provided a lens into daily teacher-student interactions. While all teachers implemented competence-supportive strategies in some form, they differed in how these strategies were framed, enacted, and experienced by students. This study highlights the nuanced ways in which competence-supportive instruction and student characteristics intersect to shape students\u2019 competence beliefs and underscores the value of using mixed methods approaches for capturing both broad patterns and situated, daily classroom processes in the study of motivation.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references