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Spinal cord regeneration progresses via developmental and non-developmental mechanisms in X. tropicalis
Get PDFThesis (Ph.D.)--University of Washington, 2025Human spinal cord regeneration is hampered by the inability of resident neural stem cells to regenerate developmentally derived neuron diversity and organization after injury. Unlike humans, the Xenopus tropicalis spinal cord is capable of functional regeneration after amputation, although the regenerative extent and mechanisms driving neural diversity and patterning remain unknown. During my dissertation work, I investigated if the X. tropicalis spinal cord regenerates cell diversity and patterning via the same developmental mechanisms with which it was originally made. First, I showed that the spinal cord dorsal/ventral axis is re-established by Shh signaling after injury in a similar manner to embryogenesis (Angell Swearer, Perkowski, et al. 2025). Next, I found that spinal cord regeneration deploys cell-type-specific developmental and non-developmental strategies to restore neuron diversity, in a divergence from the traditional regenerative paradigm (Angell Swearer et al. 2025, preprint). Overall, these results indicate that successful regeneration recruits a dynamic combination of developmental and non-developmental signals to complete functional healing
The Bidirectional Association of Sleep and Cancer in the Cancer Prevention Study - 3
No full textThesis (Ph.D.)--University of Washington, 2025Sleep is a multidimensional lifestyle behavior essential to human life. Unlike some lifestyle behaviors, sleep is a behavior practiced by all humans, making it a desirable lifestyle behavior to target for disease prevention and survivorship interventions. Prior research elucidating the bidirectional relationship between sleep and cancer has been limited. The objective of this dissertation was to understand how several dimensions of sleep (e.g., duration, timing, regularity) relate to cancer risk, and how the diagnosis of cancer changes subsequent sleep patterns. We leveraged data from the Cancer Prevention Study – 3, a prospective cohort of approximately 250,000 US adults aged 30-65 years at baseline. Sleep parameters were collected at baseline (2006-2013), 2015, and 2018. Cancer incidence was determined via linkage to state registries; follow-up time ended at the time of cancer diagnosis, time of death, or end of follow-up (12/31/2018). In Aim 1, we investigated the association of sleep duration and weekend catch-up sleep with cancer risk. In Aim 2, we investigated the association of sleep midpoint and social jetlag (i.e., difference between midsleep time on weekdays and weekends) with cancer risk. In Aim 3, we investigated how sleep duration changes following a cancer diagnosis. Collectively, findings from this dissertation identified social jetlag as being associated with cancer risk, with no evidence of consistent associations for other examined sleep dimensions. We also observed that sleep duration increased after a diagnosis of cancer, after accounting for prior sleep duration patterns and anticipated age-related changes. Findings from this dissertation provide robust information that may inform future cancer prevention and cancer survivorship guidelines
Management Brief: Managing the Threat of Emerald Ash Borer Invasion in a Changing Climate
Get PDFIn June 2022, the emerald ash borer (Agrilus planipennis; “EAB”) was discovered in Forest Grove, OR, marking its first appearance west of the Rocky Mountains. Forest managers fear for the future of Oregon ash (Fraxinus latifolia) and at least 8 other tree species found only in western North America. Climate change may broaden the threat of EAB invasion and will require climate-smart, proactive management to sustain healthy forests
A Prospective Micro-Costing Analysis of a Novel Opioid Overdose Diversion Center
No full textThesis (Master's)--University of Washington, 2025Importance: The opioid epidemic continues to be an ongoing public health threat which has resulted in an enormous death toll and has placed significant burden on multiple aspects of our
public health system. Responding to overdoses requires ample resources from our emergency
medical care system, but many current hospital systems are not resourced to provide wrap around
care to promote ongoing recovery to overdose patients. Multiple social service and public service
organizations have collaborated to develop a novel opioid overdose diversion center, the ORCA
center, to dually help reduce the resource burden on King County's medical system and deliver
tailored services to people with Opioid Use Disorder (OUD) who experience overdose. This
innovative clinic will not only provide immediate medical care to overdose patients but will engage
with patients to identify key community resources and medication for OUD which will help them
achieve recovery. However, the costs associated with the provision of this care are currently
unknown.
Objective: To determine the costs associated with this innovative opioid overdose diversion clinic.
Design: A prospective micro-costing analysis.
Setting: Seattle, WA
Main Outcome and Measures: Total cost and cost per patient over three years of service delivery.
Results: Total estimated costs for the ORCA Center range from 6,297,818.10 in year three, with per-patient costs declining from 2,670.83 in year three.
Conclusion: Fixed costs for the development of a novel opioid overdose center result in a
concentration of costs in the initial development year of the ORCA center. However, even with an
anticipated increase in the service population, total costs per year and costs per patient are
expected to decrease in subsequent years. Future cost analyses of the ORCA center are required to
further refine cost parameters associated with this novel opioid overdose diversion center
Harnessing Language Models for Automated Detection of Depression Severity and Suicide Risk
No full textThesis (Ph.D.)--University of Washington, 2025Depression is one of the most common mental disorders globally, and can carry an increased risk of adverse outcomes including suicide. Suicide is one of the leading causes of death worldwide and many more individuals attempt it or experience suicidal thoughts. Compounding these severe public health problems is a longstanding shortage of mental health professionals. There are too many patients for available professionals to monitor effectively, presenting opportunities for the use of technology to expand their capacity. Natural language processing (NLP) methods have been widely applied to psychologically-related text analysis tasks to draw relationships between text and the thoughts and feelings of the person who generated it, as indicators of their mental status. Two prominent areas are the detection of depression symptom severity and suicide risk. In this work, I investigated how language models can be harnessed to automatically detect depression symptom severity and suicide risk. To get the numerical representation of the text for further analysis, one common method is to extract contextual embeddings from language models. Contextual embeddings are word representations that take surrounding context into account, which can better represent the complexities of linguistic expressions than models that represent the same word the same way, regardless of their context. However, there is limited research involving clinical populations that utilize contextual embeddings from state-of-the-art language models to detect linguistic indicators of depression and suicide risk. Moreover, certain patient-generated data sources that can reveal mental status, notably text-based therapy sessions, Google search logs, and YouTube activities, remain underexplored. Relevant research has primarily concentrated on electronic health record (EHR) data and social media posts, which are subject to certain limitations. Furthermore, despite the rapid development of large language models, their clinical application remains challenging due to high computational costs and ethical concerns. To fill these gaps, I have developed a series of methods for automatic depression symptom severity and suicide risk detection or prediction utilizing state-of-the-art language models with under-explored data sources. Specifically, I have analyzed the use of contextual embeddings of first-person singular pronouns as predictors of depression symptom severity. Positive classification results on a PHQ-9-derived binary outcome were obtained when applying the methods to the deidentifiedpsychotherapy messages. To explore the use of individualized web searches for suicide risk assessment, I have evaluated the effectiveness of anomaly detection methods in identifying search pattern changes that precede a suicide attempt using Google search data. The proposed framework for semantic feature construction, which consists of initial filtering with a small language model followed by adjudication with a more advanced large language model to assess relevance to suiciderelated
constructs, provides a computationally efficient, tractable approach that can be applied to web search logs at scale. The methods were further applied to study participants’ YouTube activity data, which were combined with Google search logs in order to enhance anomaly detection performance. This work demonstrates the potential of effectively using language models for automatic prediction of depression symptom severity and detection of suicide risk using real-world datasets. It helps bridge the gap between advances in NLP and the growing need to enhance mental health service capacity, offering scalable computational tools for timely risk detection and intervention
Investigating the protective role of the hydrogen sulfide signaling pathways in cardiac and hepatic stress models
No full textThesis (Ph.D.)--University of Washington, 2025Hydrogen sulfide (H2S) is now recognized as a pivotal endogenous gasotransmitter involved in cardiovascular and hepatic physiology and pathology. In this work, we investigate the protective role of H2S signaling pathways in cardiac and hepatic stress models, suggesting potential therapeutic applications under oxidative stress and metabolic dysfunction.Doxorubicin (Dox) is an anthracycline chemotherapy agent used to treat a wide range of malignancies. Despite its potent antitumor activity, the clinical use of Dox is limited by dose-dependent cardiotoxicity and hepatotoxicity. Evidence supports the "double-edged sword" effect of H2S in hepatocellular carcinoma cells; however, little data exists on whether, and how, H2S can protect against Dox-induced toxicity.
We demonstrate that exogenously added H2S effectively protects against Dox-induced cytotoxicity in hepatic and cardiac cells, primarily through regulating WNT3 signaling and potentially altering the cell-cycle. Additionally, supplementing with H2S exhibited increased viability, decreased cell death, and reduced the production of reactive oxygen species in Dox-treated cells. Transcriptomic analyses revealed extensive modulation in gene expression following Dox-treatment that were partially mitigated by H2S, confirming its broad cytoprotective impact.
Next, we evaluated the effect of H2S on phorbol 12-myristate 13-acetate-induced hypertrophy in human cardiomyocytes. H2S reversed key hypertrophic markers and induced transcriptional changes through the modulation of early-response genes, such as ARC and EGR1, highlighting its therapeutic potential in pathological cardiac hypertrophy. Furthermore, we addressed palmitic acid-induced insulin resistance in hepatic and cardiac cells. Although H2S produced only modest transcriptomic changes, it improved metabolic markers, as evidenced by RNA-sequencing analysis.
Finally, we elucidated structural differences between the thiol methyltransferases (TMT) TMT1A and TMT1B that methylate hydrogen sulfide and quench its protective properties. This work highlighted critical aromatic residues that differ in the inhibitor selectivity of 2,3-dichloro-α-methylbenzylamine (DCMB). These insights will enable the development of a TMT1B selective inhibitor, advancing our understanding of enzyme specificity and providing a basis for therapeutic modulation of H2S methylation. Overall, this research underscores the multifaceted protective role of H2S, underscoring its significant therapeutic potential in reducing oxidative stress-related diseases
Investigating the Electronic Properties of Next Generation Moiré Materials
Get PDFThesis (Ph.D.)--University of Washington, 2025Since the discovery of monolayer graphene in 2004, van der Waals (vdW) materials have become a mainstay in condensed matter physics. Their layered nature enables us to isolate atomically thin sheets and stack them together with virtually limitless possibility. These designer 2D heterostructures also introduce a new twisting degree of freedom, in which layers are stacked with a rotational offset. The beating pattern formed between their crystalline lattices is known as a moiré superlattice and often leads to new and unexpected properties absent in the parent materials. In this dissertation, I will push the boundaries of this ever-growing parameter space through electronic characterization of various novel moiré materials. The prototypical example of a moiré heterostructure consists of two graphene layers stacked with a small interlayer twist and has been shown to exhibit a wide variety of novel electronic properties driven by strong electron-electron interactions. In the first part of this thesis, we show that adding more layers to this basic framework preserves much of the same physics and in some cases leads to entirely new electronic phenomena. Furthermore, we find that signatures of the moiré superlattice survive into bulk graphite structures, composed of up to ~40 layers of graphene. The second part of this thesis focuses on moiré systems composed of transition metal dichalcogenides, a class of vdW materials composed of alternating layers of transition metal and chalcogen atoms. In particular, twisted molybdenum ditelluride (tMoTe2) was recently found to exhibit the long-sought fractional quantum anomalous Hall (FQAH) effect, a consequence of strong electron interactions and robust band topology. We use scanning tunneling microscopy to image the energy-dependent nanoscale wave function of tMoTe2, illustrating a connection between its microscopic structural properties and band topology
Resisting Techno-Optimism: AI Literacy and the Politics of Inclusion Across Global Divides
Get PDFThis capstone critically examines the intersection of artificial intelligence (AI), education, and global equity, challenging techno-optimistic narratives that frame technological progress as inherently beneficial. Drawing on socio-technical systems theory, critical pedagogy, and epistemic justice, the study explores how AI literacy can serve as a transformative tool for resisting exclusionary practices and promoting justice-oriented engagement across global divides. Through qualitative methodologies, including faculty interviews and observational data from workshops, the research identifies systemic gaps in AI governance, ethical frameworks, and pedagogical integration within higher education.
Case studies on surveillance technologies, biometric systems, and algorithmic labor illustrate how AI infrastructures reproduce inequities, particularly for marginalized communities in the Global South. Findings reveal fragmented institutional policies, uneven access to AI resources, and epistemic harms embedded in algorithmic design. The study concludes with actionable recommendations for universities to embed critical AI literacy into curricula, adopt inclusive governance frameworks, and foster global collaboration to democratize technological futures. By reframing AI literacy as a civic competency rather than a technical skill, this work advocates for equity-driven strategies that resist techno-optimism and center human rights in the age of artificial intelligence
Nitrogen Isotope Analysis of Nitrogen Cycling in Coral Host Tissue and Algal Symbionts: A Study of Acropora Spp. and Stylophora Spp. near the Fulong Reefs in Taiwan
Get PDFThis study investigated the differences in δ15N values across Coral Host Tissue, Algal Symbionts,
and Whole Tissue Sample in two coral genera, Acropora spp. and Stylophora spp., collected
from a harbor structure at the National Taiwan Ocean University Aquatic Biological Research
and Conservation Center near Fulong, Northern Taiwan in August 2024. Nine coral heads were
sampled, subdivided into tissue fractions, and analyzed for stable nitrogen isotope composition
using the denitrifier method, which reduces the sample’s nitrate (NO3
-) to nitrous oxide (N2O).
Using nitrogen isotopes (δ15N) as a nutrient tracer, this study explored three hypotheses regarding
nitrogen cycling within the coral holobiont: the Host Coral provides nitrogen to the Algal
Symbionts directly through the system, the Host Coral provides nitrogen to the Algal Symbionts
indirectly through the system, or the Algal Symbionts do not receive nitrogen from the Host
Coral but instead fix dissolved inorganic nitrogen from the environment. Significant differences
in δ15N were found between Coral Host Tissue and Algal Symbionts, suggesting that corals feed
their symbionts indirectly. Genus-specific differences were also observed, with Acropora spp.
exhibiting higher δ15N values across tissue types compared to Stylophora spp., likely due to
variations in trophic strategies, metabolic demands, and morphological characteristics.
Additionally, this study found that Algal Symbionts have a greater influence on Whole Tissue
Samples δ15N than Coral Host Tissue, reflecting their varying diet and nutrient uptake patterns.
This study contributes to the growing body of knowledge on coral nitrogen cycling, emphasizing
how nitrogen isotopes can illuminate the complex interplay between coral hosts and their algal
symbionts
Settling upon the "Inside" Worlds: Sovereignty and Overlapping Territorial Conflicts in the Qing Xinjiang Crisis, 1860s-1880s
No full textThesis (Master's)--University of Washington, 2025In the mid-19th century, as the Dungan revolution was spreading in Xinjiang, Yakub Beg, a khanate from the Kokand kingdom in Central Asia, established an independent Muslim regime in southern Xinjiang, the western "outer dependencies" of the Qing Empire. Hence, the Qing's tributary international order in Central Asia, as well as Xinjiang's ontological status within the Qing empire and internationally, have been challenged unprecedentedly since the Qing's annexation of Xinjiang in the 1700s. This essay will redefine the conceptual scope of Manchu sovereignty and explore the evolution, balance, and consequences of territorial conflicts in Xinjiang during the Qing empire's modern state transition period, to challenge the static rather than dynamic view to evaluate the nature of the Qing regime. I will cite official court materials and statecraft scholars' memorials and letters to try to prove that, based on the Manchu sovereignty in Inner Asia, how the Manchu rulers made non-mainstream political decisions during the controversy among Han statecraft scholars over whether the Qing should abandon Xinjiang and thus, launched a violent and bloody conquest war in the west of Qing empire once again. In this war, the Qing empire joined the bilateral competition of the Central Asia "great game" between Britain and Russia in the final stage. The traditional tributary suzerain system and the Westphalia sovereignty state system were inextricably linked in the two negotiations between the Qing empire and Britain in the Southern Xinjiang and Russia in the Ili, accompanied by the alternate victory of the Xinjiang-preserving faction and the Xinjiang-abandoning one within the empire. The results show that the multi-parties international negotiations involved in this war ended the Qing Empire's worldview of unlimited and defenseless Xinjiang. As the buffer zone defense lines between the Qing Empire and Tsarist Russia, a powerful competitor, retreated from their Central Asian neighbors to the frontier position of Xinjiang, the resulting anxiety about the border security triggered a huge shift in the governance logic of the Qing Empire in Inner Asia and the institutional reforms. Although, this reform shook the legitimate pedestal of Manchu sovereignty and put the Qing Empire in another kind of unseen danger, which continues to affect China today