Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item Examining Consumer Product Use And Phthalate Exposure Among Vulnerable Populations(2023) Boyle, Meleah; Quirós-Alcalá, Lesliam; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)One in 13 Americans have asthma, and higher rates have been reported among women and Black children.1 In addition, hairdressers who are exposed to chemicals through products used on themselves and their clients frequently report respiratory symptoms and conditions.2–10 Limited studies indicate that chemicals in personal care and consumer products (PCP) may impact respiratory health.11–14 The goal of this dissertation is to describe PCP use and exposures to recognized and suspected respiratory irritants (phthalates) among vulnerable populations who may experience disparate exposures. The aims are to: 1) characterize PCP use among 110 children with asthma, 2) examine associations between PCP use and asthma morbidity among 110 children with asthma, and 3) characterize concentrations and exposure determinants to phthalate metabolites in post-shift urine samples among 23 female hairdressers and 17 female office workers. In aim 1, participants were majority Black (87%), males (56%), and aged 8-11 years (66%). Adolescents (12-17 years) and females reported more frequent use of hair, face, and body products compared to children (8-11 years) and males. Participants used chemical treatments on their hair as young as 4 years and females 11-16 years used feminine wipes, spray, and regular deodorant in the genital area. For aim 2, use of aerosol products, hair products, and nail polish were positively associated with maximal symptom days [number of aerosol products (aOR: 1.36; CI: 1.17, 1.59), hairspray (aOR: 1.63; CI: 1.14, 2.33), perfume (aOR: 1.40; CI: 1.11,1.77); shampoo (aOR: 1.34; CI: 1.05,1.73), hair sheen (aOR: 1.41; CI: 1.00, 2.00), nail polish (aOR: 2.42; CI: 1.72, 3.41)] among children with asthma. For Aim 3, the geometric mean (GM) for monoethyl phthalate (MEP) was 10 times higher among hairdressers (161.4 ng/mL) than office workers (15.3 ng/mL). Hairdressers who provided chemical services had higher GM MEP concentrations than those who did not: texturizing (200.2 vs. 115.4 ng/mL), relaxing (181.6 vs. 92.1 ng/mL), bleaching (182.3 vs. 71.6 ng/mL), hair color (171.9 vs. 83.2 ng/mL), and Brazilian blowout (181.4 vs. 134.6 ng/mL). Hairdressers who provided natural services had lower GM MEP concentrations than those who did not: twists (129.1 vs. 215.8 ng/mL), sister locs/locs (86.0 vs. 241.9 ng/mL), and afros (94.7 vs. 203.9 ng/mL). While larger studies are needed, this dissertation provides new data on PCP use and phthalate exposure among Black children and hairdressers.Item Novel Bioengineered Biomaterials and Tissue Culture Models to Understand Mucus Clearance Dysfunction in Asthma(2022) Song, Bongsub Daniel; Duncan, Gregg A; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Airway mucus acts as a protective barrier and vehicle of clearance for inhaled pathogens, providing the lungs with a robust defense mechanism called mucociliary clearance. Airway mucus is composed of two gel-forming mucins, MUC5B and MUC5AC that form a hydrogel that maintains functional clearance in health. However, in asthma, mucus is produced with abnormal properties that result in impaired mucociliary clearance contributing to mucus accumulation and airway obstruction. Recent evidence from clinical studies revealed that mucus obtained from individuals with asthma possesses altered mucin composition as a function of disease severity with a significant shift from MUC5B to MUC5AC as the predominant mucin. However, how these changes alter the functional properties of mucus is not yet fully understood. The overall objective of this dissertation is to understand how an imbalance in the ratio of MUC5B and MUC5AC contributes to abnormal function of mucus in asthma. The central hypothesis is that relative increases in MUC5AC enhances viscoelasticity of the mucus gel, which contributes to the functional defects of mucus. To study this, we engineered two novel approaches: (i) mucin-based biomaterials with tunable mucin composition and (ii) genetically engineered in-vitro systems with targeted knock-out (KO) of each gel-forming mucin. In our first approach, we systematically varied the mucin composition of mucin-based biomaterials and found that a rise in MUC5AC, as observed in asthma, results in increased viscoelasticity, reduced transportability, and impaired barrier function against influenza A virus. Using our second approach, we found that MUC5AC gels produced from MUC5B-KO cultures resulted in impaired mucus clearance, whereas MUC5B gels produced from MUC5AC-KO cultures lacked spatial coordination. Together, these studies suggest that elevated levels of MUC5AC contribute to enhanced viscoelastic properties, while being the key driver of impaired mucociliary clearance in asthma. This work also offers new insight into the contribution of each gel-forming mucin on the dynamic control of mucus transport and flow alignment. This work was motivated by providing a path towards developing new therapeutic targets aimed at normalizing mucus function and improving airway patency in asthma.Item THE DEVELOPMENT OF A COMMUNITY INFORMED CUMULATIVE STRESSORS AND RESILIENCY INDEX (CSRI) TO EXAMINE ENVIRONMENTAL HEALTH DISPARITIES AND DISEASE RISK IN SOUTH CAROLINA(2017) Naney, Kristen Burwell; Wilson, Sacoby M; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Communities with environmental justice (EJ) issues usually have disparities in exposure to chemical and non-chemical stressors and health status compared to other communities without underlying EJ issues. Improving cumulative risk assessment (CRA) screening tools and models can provide the necessary information needed to reduce health disparities and create more resilient communities. To address these gaps in EJ science, this dissertation has three specific aims: 1) Identify perceptions of environmental and resilience factors that may influence health among African-Americans in North Charleston, South Carolina (SC) (Study 1), 2) Develop a Cumulative Stressors and Resiliency Index (CSRI) used to rank risk in SC (Study 2), and 3) Examine associations between CSRI scores and risk of asthma hospitalizations/emergency department (ED) visits in SC (Study 3). Community stakeholders (N=18) participated in key-informant interviews and completed a 26-item paper survey in study one. Interviews were transcribed and coded, while mode, frequencies, and percentages were calculated for each indicator based on its ability to influence health. Statistical tests performed in study two included a Principal Component Analysis (PCA), one-way analysis of variance (ANOVA), and linear regression performed in SAS Enterprise Guide 7.1. Choropleth maps were also developed in ArcMap 10.5. We concluded by calculating descriptive statistics by Environmental Affairs (EA) region, Spearman’s rank-order correlation, one-way ANOVA, and negative binomial regression analyses in study three. Many of the indicators (61%) were rated as extremely high priority items and included environmental hazards, sociodemographic attributes, and factors that may influence resiliency. CSRI scores ranged from 7.4 – 64.0 with a mean score of 29.1. Statistically significant differences in CSRI scores were evident by EA region (p <0.0001) and a one-unit increase in the percentage of non-white populations per census tract projected to increase CSRI scores by roughly 6.1%. The CSRI was not able to predict risk of asthma hospitalizations/ED visits as hypothesized. Overall, we demonstrated that identifying and addressing chemical and non-chemical stressors and resiliency gaps in areas impacted by environmental injustice may lead to overall improvements in community resilience. We anticipate this work will be used as a blueprint to build more resilient and equitable communities in SC.Item Environmental Risk Factors, Health and the Labor Market Response of Households in the United States(2008-08-04) Veronesi, Marcella; Alberini, Anna; Cropper, Maureen; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In the first part of the dissertation, I estimate the effect of a married adult's specific health condition on his or her own labor market decisions (labor force participation, earnings, hourly wages, and hours of work) and his or her spouse's. I focus on cancer, stroke, ischemic heart disease, emphysema, chronic bronchitis, chronic obstructive pulmonary disease (COPD) and asthma. The effects differ by health condition and duration of the disease. Among married men who are working, having had emphysema for less than one year is enough to reduce the earnings of a man with college degree to those of a healthy man without high school diploma. My results also suggest that if a man has had cancer, his wife may have to compensate for the ensuing loss in household income by working more hours or entering the labor force. In the second part of the dissertation, I focus on the effect of children's asthma on mothers' labor force participation, on fathers' and mothers' labor supply, and on their hourly wages and weekly earnings. I compare these effects to those of a set of health conditions that includes deformities, congenital anomalies, heart problems, epilepsy and cancer. I find that single mothers with chronically ill children are the most affected group in terms of hours of work lost and reduction in earnings, and that fathers with an asthmatic child less than six years old work more hours per week. Then, I explore how mothers' labor force participation and hours of work affect days missed from school of a chronically ill child. I find that maternal employment is associated with a higher probability of a child missing school, and that this effect is the same for healthy children as for asthmatic children. In contrast, I find that if the mother works, then a child with deformities, congenital anomalies, heart problems, epilepsy or cancer is less likely to experience lost school days than if the mother does not work. I estimate the magnitude of these effects using data from the Medical Expenditure Panel Survey for U.S. households from 1996 to 2002.