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Exploring the effects of salinity and temperature gradients on Nereocystis luetkeana sorus incubation and subsequent spore release in the San Juan Islands
No full textClimate change continues to subject kelps of the Salish Sea to unpredictable and
unforeseen conditions. Circumstances such as increased freshwater input from riverine outflow
and rising temperatures in the estuarine waters of Washington State and British Columbia have
been attributed as leading causes for widespread kelp decline. To assess the potential for
compounding deleterious effects induced by large temperature and salinity swings, bull kelp
(Nereocystis luetkeana) sorus samples were collected from two nearshore habitats along the
Friday Harbor coastline. The sori were then incubated in a range of conditions from 8ppt - 32 ppt
salinity and 10°C - 22°C in an attempt to mimic recently observed conditions in local waters.
The results highlight a small window of viable incubation for the most extreme end (low salinity,
high temperature) of the exposure gradient while requiring longer durations for those in control
treatments, depending on specific incubation parameters. An exploration into the effects of a
range of salinity and temperature exposures during the sorus development of the brown algae,
Nereocystis luetkeana, returned mixed spore density results, with varying incubation success.
The state of the sori also varied during incubation, with boils appearing on all of the 8ppt
treatments except for in phase 3 with the 8ppt 10°C treatment sori. For spore density, the highest
density observed was in the 32 ppt 16°C treatment, and the most evident relationship visible was
shown by lower spore count at lower salinities
The association between intensive parenting attitudes and topical fluoride opposition
No full textThesis (Master's)--University of Washington, 2025Introduction. Despite evidence that topical fluoride is safe and effective, opposition to it is a growing clinical and public health challenge. Intensive parenting attitudes may affect a caregiver’s preventive care decision-making for their children, including decisions about fluoride, but no studies exist on how intensive parenting attitudes influence topical fluoride opposition. The objective of this study is to investigate the association between intensive parenting attitudes and topical fluoride opposition. Methods. This was a secondary analysis of data on caregivers’ beliefs about fluoride for their children. An 85-item survey was administered from November 2020 to September 2021 (N=1,135). Participants were eligible if they were an English-speaking caregiver of a child under 18 years. The outcome variable was topical fluoride opposition, defined as how opposed the caregiver was to topical fluoride for their child (self-reported scale of 0-10). The explanatory variable was intensive parenting attitudes, defined as the extent of child-centered, time-intensive, and self-sacrificing parenting, measured as a composite score from three survey items. Linear regression was used to test the study hypothesis, adjusting for confounders. All analyses were performed in SPSS.
Results. The mean±SD caregiver age was 41.7±8.8 years, with most caregivers being women (73.0%), white (55.5%), non-Hispanic (79.3%), having greater than a 4-year degree (28.5%), and having private dental insurance (45.1%). The mean±SD topical fluoride opposition score was 2.0±3.1, and the mean±SD intensive parenting attitudes score was 1.7±0.4. After adjusting for confounders, a 1-point increase in intensive parenting attitudes score was associated with a 0.3-point increase in topical fluoride opposition score (95% CI: 0.1, 0.4; p<0.001).
Conclusions. Intensive parenting attitudes were significantly and positively associated with topical fluoride opposition. Clinicians can utilize these findings to assess caregivers’ intensive parenting attitudes, learn about concerns, and address them by tailoring communication strategies to discuss appropriate risk-based recommendations about topical fluoride
Developing non-invasive neuroimaging biomarkers for Alzheimer's disease using machine learning
No full textThesis (Master's)--University of Washington, 2025With the FDA’s recent approval of the anti-amyloid antibodies lecanemab and aducanumab, the prospect of disease-modifying therapies for Alzheimer’s disease has become a clinical reality. However, these treatments are only effective in the early stages of the disease which is why there is a need for accurate AD early detection methods. PET imaging has the ability to detect key biomarkers associated with AD up to 20 years before symptoms occur. However, PET is largely unavailable in many countries and even in the U.S. is limited and costly. Here, we present a deep learning framework for synthesizing Aβ, Tau, and FDG-PET from MR images, which can reduce reliance on standard PET imaging by reconstructing the same pathology from learned representations in the MR inputs. We find that our UNet is able to synthesize structurally similar and clinically relevant Aβ, Tau, and FDG-PET images, potentially introducing MRI as a more accessible biomarker detection modality. Early AD is also characterized by network-wide functional connectivity changes, which have been observed in the DMN and other regions including the salience and dorsal attention regions. Currently, functional connectivity evaluation methods do not incorporate spatial information into their analysis nor do they evaluate connectivity dynamically, which neglects important interactions that occur in the brain. In the second portion of this thesis, a previously developed Graph Diffusion Autoregressive (GDAR) Model is applied to fMRI data to analyze dynamic functional changes in physiologically distinct brain networks. We found notable differences in connectivity among AD versus control subjects, informing future analysis to develop features that can separate AD from control subjects with the ultimate goal of developing AD early detection functional biomarkers
The Role of Slc20a2 in Osteogenesis
No full textThesis (Ph.D.)--University of Washington, 2025The role of inorganic phosphate transporters at the bone surface remains largely unknown. Prior work has established that Slc20a2, which encodes type III sodium-dependent phosphate transporter PiT-2, plays a crucial anti-calcific role in both vascular and brain tissues and physiologic osteogenesis. This work investigates Slc20a2 expression in bone cells and explores the mechanisms that lead to impaired osteogenesis when Slc20a2 is lost. Tibia samples were collected from C57Bl6/J and C57Bl6/J CD-1 outbred mice carrying the EUCOMM tm1a knockout-first cassette. Whole-tissue X-Gal staining identified Slc20a2 localization to a bone-lining adjacent cell type. Publicly available single-cell RNA-seq (scRNA-seq) datasets were analyzed to corroborate expression signatures across different bone cell populations. To examine gene expression changes in situ, a demineralization protocol was optimized to preserve RNA. Subsequently, spatial transcriptomics (Nanostring GeoMx DSP and 10X Genomics Visium HD) was performed on demineralized bone sections, and immunofluorescence studies further validated the identity of various vascular and bone cell types. Finally, SPiDER-βGal (Dojindo) was employed to sort LacZ-expressing cells from heterozygous and knockout mice, enabling mRNA-seq to confirm their specific identity. Early observations in dental tissues also provided insight into Slc20a2 localization and its effects on mineralization. Key findings indicate that Slc20a2 deficiency impairs osteoblast numbers and function. X-Gal staining localized Slc20a2 to bone-lining cells between marrow vasculature and osteoblasts, suggesting a bridging position between osteoblasts and blood vessels. scRNA-seq data showed Slc20a2 expression is highest in CXCL12-abundant reticular cells, specifically osteo-CAR cells. Additional markers, including Limch1 and KCNK2, co-localized with X-gal staining, validating these observations. Spatial transcriptomic approaches confirmed the cell-specific marker expression in carefully defined regions of interest, and RNA-seq of sorted Slc20a2-deficient LacZ-expressing cells further supported these findings. Moreover, Slc20a2 loss resulted in defective molar mineralization and heightened susceptibility to incisal wear or fracture. Notably, the inner and outer enamel epithelia—especially the stratum intermedium—showed robust Slc20a2 expression. Overall, this work reveals that Slc20a2 is highly expressed in osteo-CAR cells at the endosteal–bone marrow interface, a population that may regulate osteogenesis either by signaling cues or by providing a reservoir of pre-osteoblasts. These insights offer a novel perspective on how inorganic phosphate regulation and Slc20a2 expression could be leveraged in clinical settings to address bone disorders such as osteoporosis
Aerospace Applications of Noise Covariance Identification with Autocovariance Least Squares
No full textThesis (Ph.D.)--University of Washington, 2025State estimation is necessary to support state feedback control applications whenever measuring the full state is prevented by environment or cost. Estimator performance depends on an accurate model of the stochastic process, however in practice noise covariances are not known and are hard to determine. The Autocovariance Least Squares (ALS) technique is a direct correlation method that identifies a system's noise covariance matrices. ALS poses a least squares problem using a linear or non-linear system model and experimentally observed measurement innovations. This dissertation addresses fielded vehicles for which ALS can be used to inform the design of state estimation filters. There are unique noise identification challenges with aerospace vehicles including the conditioning of the ALS problem, measurement of atmospheric disturbances, uncertainty in the dynamic model, and the cost and time required for data collection. Extensions of the ALS technique are developed to address these challenges. The extensions are applied to design state estimation filters for four aerospace systems for both simulated and experimentally collected data. The systems considered are the University of Washington's two gust load alleviation wind tunnel test-beds; the 3 ft x 3 ft Model for Aeroelastic Response to Gust Excitation and the Kirsten Wind Tunnel Large Wing test-bed, a simulated narrow body commercial aircraft, and flight test data from a wide body commercial aircraft
Evaluating Early-Age Volume Change and Performance of Polymer Modified Belitic Calcium Sulfoaluminate (BCSA) Cements: Field and Lab testing
No full textThesis (Master's)--University of Washington, 2025Bridge deck cracking is an increasingly prevalent issue, with limited repair times due to mobility and safety constraints restricting the use of conventional high-early-strength concrete (HESC). This study developed a HESC overlay mix using a belitic calcium sulfoaluminate (BCSA) cement-based system and identified key challenges to its reliable field implementation. Four BCSA systems were evaluated for fresh properties, mechanical strength, and durability performance: CSA with Integral Low-PTM (CSAP), CSA with Liquid Low-PTM (LLP), and latex-modified CSA at 25% (LM25) and 100% (LM100) of the standard latex quantity. The CSAP and LLP mixes were applied as overlays on mini-bridge decks to assess their performance and compatibility with existing substrates under simulated field conditions. In laboratory testing, LLP showed comparable or better strength to CSAP, improved durability over the latex-modified mixes, reduced shrinkage, better air content, and acceptable workability. However, on mini-bridge decks, LLP exhibited significant cracking and underdeveloped mechanical properties. While laboratory results indicate potential for both LLP and CSAP, further research is needed to evaluate the long-term durability and mechanical performance under field conditions. A deeper understanding of the interactions between polymer types and air-entraining admixtures is also essential to improve performance and ensure reliable application
Evoking the muses: Exploring the nature of inspiration in art museums
No full textThesis (Master's)--University of Washington, 2025Art museums have a unique capacity to elicit positive emotions, with inspiration emerging as a particularly meaningful yet underexplored emotion. This quantitative study investigated whether and how adults experience inspiration during art museum visits. Data were collected through semi-structured interviews with 54 adults at three U.S. art museums. Results indicate that inspiration is a common emotional response during art museum visits, often characterized by shifts in perspective, feelings of motivation, and admiration. Participants attributed their inspiration to various aspects of the art museum experience, including personal relevance, the formal qualities of artworks, the perceived intent of artists, and the juxtaposition of different artistic ideas. While inspiration was strongly reported, participants also experienced related emotions such as joy and excitement. Findings support the belief that inspiration correlates with perspective shifts and motivation. The study contributes to the growing body of research highlighting the emotional impacts of museum visits and underscores the potential of inspiration to support visitor well-being. Implications for museum practice include enhancing interpretative strategies to foster personal meaning-making and promoting continued engagement beyond the museum visit. Further research is recommended to explore the long-term impacts of museum-inspired motivation and to diversify participant demographics
Mortality risks in multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis: a systematic review and meta-regression analysis
No full textThesis (Master's)--University of Washington, 2025Tuberculosis (TB) remains a leading cause of infectious disease mortality globally, and the emergence ofdrug-resistant strains poses a significant threat to TB control efforts. This study aimed to quantify the
relative mortality risks associated with multidrug-resistant TB (MDR-TB) and extensively drug-resistant
TB (XDR-TB), in comparison to drug-susceptible TB (DS-TB) and MDR-TB, respectively. A systematic
review was conducted following PRISMA guidelines, and eligible studies reporting comparative mortality
outcomes were identified through PubMed, Embase, and Global Health databases.
A total of 62 studies were included in the meta-analysis. Random-effects models were used to pool relative
risk estimates, and meta-regression analyses were conducted to explore the influence of contextual
moderators such as country income group, HIV status, and urbanicity. Results showed that MDR-TB was
associated with significantly higher mortality compared to DS-TB, particularly in low-income countries
and among populations exclusively living with HIV. For XDR-TB versus MDR-TB, urbanicity emerged as
a significant moderator, with higher mortality observed in urban settings. XDR-TB exhibited consistently
elevated mortality across most contexts, indicating the limited moderating effect of structural variables
beyond urbanicity.
These findings highlight the disproportionate impact of drug resistance on vulnerable populations and
underscore the urgency of expanding diagnostic and treatment capacity in high-burden, low-resource, and
urban settings. This work contributes to the global evidence base supporting more equitable TB control
strategies and context-specific public health interventions
Characterizing drug use incidents on transit vehicles and its impact on transit operators
No full textThesis (Ph.D.)--University of Washington, 2025Drug misuse, specifically of synthetic opioids and methamphetamines, has increased in the United States, often occurring on public transit, creating potential for secondhand exposure for transit operators. These exposures could result in physical or mental health impacts. Here, we characterize drug use incidents on transit vehicles and its impacts on transit operators. Using a quantitative survey of transit operators in the Pacific Northwest, we fit ordinal logistic regression models to investigate transit operators’ perceived risk of workplace exposure to drug use incidents, occupational stress, and job satisfaction, and their association with intent to leave their job. We found that higher perceived risk scores were significantly positively associated with greater intent to leave (OR: 1.08; 95% CI: 1.02, 1.14), but occupational stress and job satisfaction, which were significantly associated with greater intent to leave, attenuated this relationship.We subsequently conducted qualitative interviews of transit operators to explore their experiences with passenger drug use, risk perceptions, impacts, availability and effectiveness of existing supports and guidance pertaining to passenger drug use, and whether there are unfulfilled needs in these supports. Interviewees reported physical health effects, mental health outcomes, and emotional impacts. Risk perceptions of passenger drug use were prevalent and may be exacerbated by outrage factors. Operators reported a lack of support from their agencies, and highlighted engineering controls as an effective intervention that is currently unfulfilled.
We then examined temporal and weather-related trends in drug use on transit, based on previous transit operator concerns that people who use drugs (PWUD) seek transit vehicles as shelter to escape from inclement weather. Using a dataset of drug use incidents reported by transit operators in King County, Washington, in 2022, we fit a Poisson regression model to understand the association between daily incident count and daily weather patterns. Reported drug use incidents showed clear temporal trends, with a higher frequency of incidents in winter and spring than in summer; April had the highest mean daily incident count of 7.3 incidents/day. Higher temperature was significantly associated with lower incident count (IRR: 0.96; 95% CI: 0.95, 0.97).
The work presented here highlights the impacts of drug use incidents on transit operators, and can help guide the development and timely deployment of interventions that can improve the work experiences of transit operators
Interpretation of Visible Labs: The Benefits and Drawbacks
No full textThesis (Master's)--University of Washington, 2025Natural history museums (NHMs) face a conundrum: they appeal broadly to audiences yet struggle to compete with other informal science venues such as science centers, aquariums, zoos, and botanical gardens (Steiner & Crowley, 2013). NHMs are unique in that they hold collections, and many are also sites of active research. More recently, some of these NHMs have begun to showcase their research to the public via visible lab spaces. These attributes can position NHMs as distinctive sites for public engagement. Despite their potential, relatively few studies have examined the unique role of visible labs in informal learning venues such as NHMS. This study investigated the interpretative strategies used within visible labs and examined how these strategies aligned with educational frameworks. A case study approach including interviews with museum professionals engaged in interpretive planning and interpretation for visible labs and supplemented with document analysis was employed. Findings show that the unique features of visible labs include the process of science as a learning outcome, the demystification of scientists and science, and personalization and connection between the public and scientists. However, to leverage these benefits, scientists in visible labs need more support and validation. These findings demonstrate that visible labs are a unique resource for NHMs, adding to their value and separating them from other informal science venues