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School Routines of Family Engagement and Advancing Educational Equity
No full textThis dissertation explores the extent to which school opportunities for family engagement—or the school-level routines and practices that build relationships with families—address or exacerbate challenges to family engagement. The three studies use data from the nationally representative Early Childhood Longitudinal Study, Kindergarten Class of 2010-11.
The first study uses parent data and path analysis to examine how family characteristics, including race/ethnicity and socioeconomic status (SES), relate to family engagement and the barriers confronted by families. The findings suggest that scheduling and environmental barriers negatively mediate the relationship between family background and family engagement practices conducted at school; barriers are unrelated to family engagement practices conducted at home. Schools may be systematically excluding some racialized and lower-income families by emphasizing school-based practices.
The second study uses school-level data and latent profile analysis to categorize schools with similar opportunities for family engagement. The analyses identify four different approaches that schools take with family engagement: fewer routines and no PTO/PTA (Profile 1); fewer routines and PTO/PTA (Profile 2); more school-based routines (Profile 3); and more outreach and home visits (Profile 4). The four profiles reveal variations in the quantity and the types of family engagement practices emphasized by schools.
The third study, using multi-group path analysis, explores how the relationships identified in the first study differ across the school profiles identified in the second study. Analyses indicate that schools with high outreach to families may reduce associations between family background characteristics and barriers, suggesting a reduction in the systematic exclusion of minoritized families.
This dissertation suggests that when schools thoughtfully and critically implement family engagement—particularly focusing on outreach to families—school-based family engagement experiences may become more equitable. Schools should also recognize and encourage the home-based practices that are already conducted by minoritized families and less hindered by barriers
From Parthanatos to PAANIB-1: A Multimedia Exploration of Cell Death Mechanisms and Therapeutic Strategies for Parkinson's Disease
Get PDFRecent discoveries in molecular biology have shed light on a potential therapeutic treatment for Parkinson’s disease (PD)—a progressive neurological disorder marked by the gradual loss of dopaminergic neurons in the brain.¹ This treatment involves selectively intervening in the parthanatos pathway, a preventative cell death mechanism that normally helps restrict the cell-to-cell spread of disease.² This cell death pathway is characterized by its distinctive breakdown of the cell’s DNA into fragments that escape from the nucleus into the cytoplasm prior to degrading.³
In addition to parthanatos, the cGAS-STING pathway is another molecular mechanism that produces a rapid microglial immune response upon detection of cytosolic DNA fragments.4 Thus, the cGAS-STING pathway is linked to the elimination of infected cells by sensing and responding to foreign DNA, as well as self-DNA fragments created through parthanatos.5 In neurogenerative diseases such as PD, both pathways become excessively engaged and overactivated—perpetuating a cycle of widespread inflammation and cell death.
Traditionally, it has been believed that blocking the initial stages of parthanatos would be the most effective in preventing DNA fragmentation and cell death.6 However, targeting the early steps of parthanatos has drawbacks, as this inadvertently hinders essential DNA repair. Therefore, new research has shifted focus downstream to prevent parthanatos-induced DNA cleavage without interfering with important upstream DNA repair processes. In particular, Macrophage Migration Inhibitory Factor (MIF) nuclease has been identified as the critical molecule for initiating self-DNA cleavage in cells, thereby triggering the decisive step of parthanatos.3,6
Exciting new research has unveiled PAANIB-1, a first-in-class MIF inhibitor that prevents this final step of parthanatos, thus also preventing the generation of DNA fragments that over-activate the cGAS-STING pathway.8,9 Targeting MIF using PAANIB-1 therefore shows promising potential in its ability to slow or prevent inflammation and neuronal damage in PD.8,9 As further testing for PAANIB-1 viability proceeds, it is crucial for researchers, students, donors, and patients to understand both PD pathogenesis and this novel, highly-targeted intervention strategy. I aim to transform these findings into a didactic, highly engaging 3D animation and interactive web module, catering to both scientific and lay audiences
APPLICATION OF RISK ASSESSMENT METHODOLOGY FOR OXYGEN DEFICIENCY HAZARDS (ODH) BASED ON INDIVIDUAL COMPONENTS OF CRYOGENIC SUBSYSTEMS
Get PDFThe use of cryogens is widespread across multiple industries and is commonly used in research to handle or store chemicals and materials under low temperatures and highly controlled conditions. Nitrogen, argon, helium and hydrogen are the most commonly used cryogens in research settings and will be of primary focus throughout the risk assessment methodology to be discussed within the scope of this project, conducted at Research Center X. Cryogens exist as liquids at low temperatures, but are released as gases when introduced to environments at normal temperature and pressure. Cryogenic liquids expand by a factor of 700 upon release to their gaseous form, increasing the likelihood for a decrease in oxygen concentration when handled in a space of limited volume. These cryogenic gases have the potential to accumulate and displace the oxygen within a space, posing an acute concern if an oxygen deficient atmosphere, defined by OSHA as less than 19.5% O2 (OSHA, n.d.), is created.
Existing risk assessment of work processes involving cryogenic liquids and asphyxiant gases at Research Center X focuses solely on the volume of the gas used and the volume of the area in which it is handled. The goal of this project is to expand this risk assessment by developing a classification system for Oxygen Deficiency Hazards (ODHs) based on the level of risk specific to an “event” (failure) of each component of a cryogenic system. The main components within each cryogenic system include a pressurized vessel, tubing, valves and regulators, specific to the unique needs of each system. Work processes have been categorized by the nature of each task depending on the expected failure rate of the event to occur (per hour) and the probability of a fatality to occur due to the event. These factors were then used to calculate an overall ODH fatality rate for the usage scenario, classified as ODH 0, 1, or 2, with ODH 0 being the least hazardous and ODH 2 being the most hazardous
A PCR-based approach for the identification of specific host blood meals in field-collected anopheline mosquitoes
Get PDFVector-borne diseases account for significant morbidity and mortality globally and heavily affect tropical and sub-tropical regions of the world. The transmission of these diseases is mediated by hematophagous arthropods which acquire pathogens from blood meals from infected hosts. Feeding behaviors of these arthropods can provide insight into the epidemiology of disease allowing for the development of novel vector control strategies that will benefit populations throughout disease-endemic areas and novel transmission foci. Through the development of a blood meal identification tool, hosts of medically important arthropods can be rapidly identified allowing for the implication and identification of potential vectors and reservoirs of pathogens. Current blood meal identification assays utilized at field sites located in Zambia do not provide the specificity necessary to examine the foraging behaviors of anophelines at a great scale. The aim of this thesis project was to develop a multiplexed PCR assay to rapidly identify specific host blood meals taken by anopheline mosquitoes at these field sites. This tool can identify human, pig, dog, chicken, duck, cow and goat blood meals using three different mtDNA targets. In addition, blood meal analysis was completed on field samples collected in Nchelenge, Zambia in 2020.
The assay was optimized and validated using controls extracted from blood and tissue. Consistent detection of host DNA was possible at 0.078 ng/µL for most hosts of interest and detection of mixed DNA controls was also possible. Blood meal analysis was completed on anopheline samples collected in 2020 as part of cross-sectional analyses of mosquitoes from Nchelenge. The majority of samples collected were Anopheles funestus s.s. with An. gambiae s.s. being the second most collected. Blood meals were identified in 6.8% of samples analyzed using the PCR assay, and consisted of human, goat and mixed human/goat meals. These samples were stored on silica and cotton for three years prior to testing, highlighting the tools ability to detect blood meal sources after long-term storage. Adding this assay to current vector surveillance strategies could serve as an important source of information to expand the knowledge and roles of anophelines in the transmission of malaria in Nchelenge
HE Nuclei Segmentation at 20x Magnification
Get PDFDigital pathology has revolutionized the study of histological images, deriving new insights into tissue characteristics and pathologies. Fundamental tasks within the field such as cell counting, classification, and quantifying intercellular spatial relationships are enabled through effective nuclei segmentation. Several CNN-based approaches have been proposed to tackle the challenge of nuclei segmentation in H&E images; however, existing models are commonly trained on publicly available datasets captured at 40x magnification. While this higher magnification offers superior spatial resolution for precise segmentation, working with such large image sizes (e.g., a standard tissue area of 15mm x 15mm resulting in ~70,000 x 70,000 pixels) can be computationally intensive and limit practical applicability in whole slide image (WSI) analysis. In this study, we developed a comprehensive dataset specifically focused on 20x magnification nuclei image segmentation. This dataset combines publicly available data with our own meticulously annotated images. We trained the SD_HE_20x model based on the StarDist network, which demonstrated comparable performance to segmentation results obtained with 40x images but with significantly reduced computational time (~3 times faster). The SD_HE_20x model also offers speed and adaptability by providing pre-trained weights for sample-specific retraining. For access to the model, test data, and WSI implementation code, please visit https://github.com/JLanan/StarDist-20x-HE. This repository houses all resources related to our study, facilitating reproducibility and further research in the field of digital pathology and nuclei segmentation
Investigating Electrochemical Activation of Small Molecules on Molecular and Material Platforms Through In situ Spectroscopies
No full textEnergy conversion and storage are crucial elements in the development of a sustainable energy infrastructure. Particularly noteworthy is the storage of energy from renewable sources into energy-dense, industrially relevant commodity chemicals. In recent years, there has been a significant focus on carbon dioxide (CO2) conversion due to the increasing atmospheric concentrations resulting from anthropogenic emissions. This work focuses on enhancing the synthetic complexity of these reactions to enable access to a broader range of products.
This thesis presents a series of interconnected narratives detailing the electrochemical conversion of CO2 with various nitrogen-based precursors to enable C-N bond formation. Chapter 1 begins with an introduction to catalysis and electrocatalysis, while also providing context behind the benefits and limitations of heterogenous or homogenous catalytic systems.
Chapter 2 described the impact of electrolyte effects on coupling CO2 and NO3- to form urea at a polycrystalline gold electrode. Intermediates were tracked using in situ IR spectroscopy resolving the formation of both carbamate and urea. Computational analysis supports this work by detailing the potential intermediates for C-N coupling on gold.
Chapter 3 discusses a follow up study to Chapter 2 where we began characterizing the role that material design parameters play in electrochemical C-N coupling. This work was further characterized through in-situ X-ray absorption spectroscopy, Raman spectroscopy, and electrochemical methods.
Chapter 4 represents a turning point in this thesis as we were interested in studying how C-N coupling might occur using a catalyst with molecular active sites. This system was characterized through in situ IR spectroscopy revealing reaction intermediates. To further understand transformations of the active site during electrolysis, we performed X-ray absorption spectroscopy and observed dramatic changes of the active site under varying conditions. Atomic-scale simulations validate experimental observations that C-N coupling occurs through a solution phase hydroxylamine (NH2OH) and a stable *CO intermediate to yield the final product, urea.
Chapter 5 is a conclusion to the mentioned works while also delving into the future directions for this work. Looking ahead, the prospects for this work are promising, with opportunities for expanding the synthetic complexity of heteroatom coupling reactions and exploring new avenues for energy storage and utilization
Machine learning-guided accelerated discovery of structure-property correlations in lean magnesium alloys for biomedical applications
Get PDFFrontloaded Home Health Physical Therapy Reduces Hospital Readmissions among Medicare Fee-for-Service Beneficiaries
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Objective
The purpose of this paper is to determine a claims-based definition of frontloaded home health physical therapy (HHPT) and examine the effect of frontloaded HHPT visits on all-cause 30-day hospital readmissions.
Methods
This study used a retrospective analysis of Medicare fee-for-service claims from older adults (≥65 years) in the National Health and Aging Trends Study (NHATS; 2011–2017) with ≥1 HHPT visit within 30 days of a hospitalization (n = 1344 hospitalizations; weighted n = 7,727,384). An exploratory analysis of home health claim distribution was conducted to determine definitions of frontloaded HHPT. Generalized linear models were then used to examine the relationship between hospital readmission and each definition of frontloading.
Results
Four definitions of frontloaded HHPT were identified: ≥2 HHPT visits in the first week after discharge; ≥3 visits in the first week; ≥4 visits in the first 2 weeks; and ≥ 5 visits in the first 2 weeks. The adjusted risk of readmission was lower for older adults receiving frontloaded HHPT in the first week: (risk ratio [RR] for ≥2 vs <2 visits = 0.57; 95% CI = 0.41–0.79; RR for ≥3 vs <3 visits = 0.39; 95% CI = 0.22–0.72). The reduction in risk of readmission was even greater for older adults receiving ≥4 versus <4 HHPT visits (RR = 0.32; 95% CI = 0.21–0.48) and ≥ 5 versus <5 HHPT visits (RR = 0.27; 95% CI = 0.14–0.50) within the first 2 weeks. The effect of HHPT frontloading was greater for patients hospitalized with surgical versus medical diagnoses and for patients with diagnoses targeted by the Hospital Readmissions Reduction Program.
Conclusion
Frontloaded HHPT reduces 30-day hospital readmissions among Medicare beneficiaries. Additional research is needed to determine the optimal number of visits and those most likely to benefit from frontloaded HHPT.
Impact
Frontloaded HHPT can be an effective approach for reducing 30-day hospital readmissions among Medicare beneficiaries.
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Identification and Estimation for Nonignorable Missing Data: A Data Fusion Approach
Get PDFWe consider the task of identifying and estimating a parameter of interest in settings where data is missing not at random (MNAR). In general, such parameters are not identified without strong assumptions on the missing data model. In this paper, we take an alternative approach and introduce a method inspired by data fusion, where information in an MNAR dataset is augmented by information in an auxiliary dataset subject to missingness at random (MAR). We show that even if the parameter of interest cannot be identified given either dataset alone, it can be identified given pooled data, under two complementary sets of assumptions. We derive an inverse probability weighted (IPW) estimator for identified parameters, and evaluate the performance of our estimation strategies via simulation studies, and a data application
IRREGULAR ADAPTATION: EVALUATING WARFIGHTING PERFORMANCE IN VIETNAM AND AFGHANISTAN AND OPTIMIZING THE UNITED STATES FOR FUTURE CONFLICT
Get PDFIn contrast to the catastrophic success of World War II, U.S. performance in the irregular wars of the latter twentieth and twenty-first centuries has disappointed. The American military ventures in Vietnam (1950-1973) and Afghanistan (2001-2021) stand out as revealing a Washington national security apparatus incapable of the adaptation required for victory. Because irregular wars, as opposed to conventional ones, are often unpredictable in enemy and environment, they require a higher degree of intellectual elasticity in strategy-making for success. Dominated by indirect, non-attributable, or asymmetric activities, the conflicts in Vietnam and Afghanistan stymied the “American Way of War” that relied on advanced technology and overwhelming firepower for triumph. In 2023, the Pentagon revamped its understanding of irregular warfare in an attempt to address this blind spot. A deeper appreciation of Vietnamese communist and Taliban adaptations reveals several fundamental flaws in the United States approach to this form of warfare. Additionally, American scholars undervalue the roles and responsibilities of Washington civilian leaders during these conflicts. Several incremental remedies taken across all levels of war-making will enhance Washington’s ability to employ its military instrument of national power optimally across a range of scenarios and contingencies. While the United States may be reluctant to take interest in irregular war, to be certain in the age of renewed multipolarity, irregular war is certainly interested in the United States