Theses and Dissertations from UMD
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Item "Get Dressed Up For The End Of The World!": The Reinvention of the Elder Goth Subculture During a Time of Crisis(2024) Bush, Leah J.; Corbin Sies, Mary; American Studies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation is an ethnographic examination of relationships between subcultural identity and Gothic social worlds in the Elder Goth subculture in Baltimore, Maryland and Washington, D.C. Formed in Britain in the late 1970s, the Goth subculture is characterized by a distinct morbid aesthetic and an overwhelming emphasis on the color black. The subculture retains a relatively high number of Elder Goths who participate in the subculture beyond their youth. This interdisciplinary project draws from the lifespan perspective of age studies and aspects of performance studies and queer utopian theory. Individual identities and Gothic communities are built and sustained through subculturally specific fashion and embodied practices at nightclubs, outdoor gatherings, and the phenomenon of virtual streaming dance nights which emerged during the COVID-19 pandemic. The project also considers how meaning is made in subcultural places. Elder Goths draw on the subculture’s embrace of dichotomies in life, commitment to adaptation, and deepen their investment with the subculture at transitional points in their lives. Subculture is thus a fluid process of worldmaking which unfolds over the life course. This dissertation underscores the power of agency in making new and better worlds.Item Investigation of progerin expression in non-Hutchinson-Gilford Progeria Syndrome individuals(2023) Yu, Reynold; Cao, Kan; Mount, Steve; Molecular and Cell Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Hutchinson-Gilford Progerin Syndrome (HGPS) is a premature aging disease caused by a point mutation in the LMNA gene, which encodes A-type lamins. This mutation activates a cryptic splice donor in exon 11 and leads to the production of a toxic lamin variant called progerin. Interestingly, small amounts of progerin have also been found in cells and tissues of normal individuals. Here we examine the expression of progerin in publicly available RNA-seq data from normal individuals of the GTEx project. Among the 30 available tissues, progerin expression in normal individuals is highest in sun-exposed skin samples, and its expression in different tissues of the same donor is correlated. In addition, telomere shortening is significantly correlated with progerin expression. Transcriptome-wide correlation analyses suggest that the level of progerin expression is highly correlated with switches in gene isoform expression patterns, perhaps reflecting widespread isoform shifts in these samples. Differential expression analyses show that progerin expression is correlated with significant changes in the level of transcripts from genes involved in splicing regulation and a significant reduction of mitochondrial transcripts. Interestingly, 5’ splice sites whose use is correlated (either positively or negatively) with progerin expression have significantly altered frequencies of consensus trinucleotides within the core 5’ splice site. Furthermore, introns whose alternative splicing is correlated with progerin have reduced GC content. Together, our study suggests that progerin expression in normal individuals is part of a global shift in splicing patterns and provides insight into the mechanism behind these changes.Item APPLYING A GENDERED LENS TO THE STUDY OF WORK AND CAREGIVING RESPONSIBILITIES AMONG CHINESE MIDDLE- TO OLDER-AGED ADULTS(2023) Ye, Jing; Chen, Feinian; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation consists of three papers that investigate the working and caregiving roles of middle-to-older adults and their implications for well-being in China. While existing literature predominantly focuses on older adults as care recipients, this research sheds light on the significant number of older individuals who actively participate in the labor market and provide informal caregiving to family members. Studies usually focus on either caregiving or employment while keeping the other in the background, leaving the intersection of work and caregiving responsibilities understudied. I then ask whether and how work-life conflicts, commonly discussed in the context of middle-aged women, are also applicable to the older population and are shaped by gender. Using data from the China Health and Retirement Study, the study investigates work and caregiving patterns among middle-to-older adults and explores the well-being consequences of juggling these roles. Furthermore, the research examines whether gender-based patterns persist in work and caregiving dynamics during this stage of life. The study is conducted in China, a developing country experiencing accelerated population aging, and the boundaries between work and family responsibilities are less distinct compared to developed societies. Early retirement age in the formal sector provides opportunities for older workers to engage in caregiving, while informal sector and agricultural workers may need to continue working until old age due to low pension rates. The culture of filial piety and intergenerational solidarity further encourages older generations to provide financial and caregiving support to their younger family members, leading to the common occurrence of middle-to-older adults taking on both work and caregiving roles. The first paper explores the association between living arrangements and middle-to-older adults’ work prospects, considering gender and work sector differences. The second paper examines the impacts of living arrangements on role transitions, especially the transitions of workers and worker-caregivers given their prevalence, while also considering the moderating effects of gender and residence. The third paper investigates the joint impact of work and informal caregiving on mental well-being, analyzing the differential effects based on intensity, gender, residence, socioeconomic status, and social isolation level. In the context of accelerated aging in developing countries, this dissertation highlights the contributions of middle-to-older adults and emphasizes the need for investment in and design of long-term care services to meet the demands of rapidly aging populations.Item BARRIERS OF AGING: THE IMPACT OF HOUSING ON U.S. OLDER ADULT HEALTH(2020) Hall, Quinshay; Roby, Dylan H; Health Services Administration; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Today, millions of older adults aged 65 and older, face the challenges of aging. In the past ten years, the number of people aged 65 and older in the U.S. increased from 37.2 million to 49.2 million, and by 2040 an estimated one in five Americans will be age 65 or older (Administration for Community Living & Administration on Aging, 2018; Urban Institute, 2014). Housing is a significant factor in health outcomes for this population because of their increased time spent in the home, which can put them at an increased risk for home accidents (Newman, 2003). Using the Health and Retirement Study, this study explores the association of assistive features being present in one’s home on health status and provides evidence to identify the housing needs of the older adult population.Item Auditory Temporal Processing Ability in Cochlear-Implant Users: The Effects of Age and Peripheral Neural Survival(2019) Shader, Maureen Joyce; Goupell, Matthew J; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cochlear implants (CIs) are a valuable tool in the treatment of hearing loss and are considered a safe and effective option for adults of all ages. Nevertheless, older adults with CIs do not always achieve comparable speech recognition performance to younger adults following implantation. The mechanism(s) underlying this age limitation are unknown. It was hypothesized that older CI users would demonstrate age-related deficits in auditory temporal processing ability, which could contribute to an age limitation in CI performance. This is because the ability to accurately encode temporal information is critical to speech recognition through a CI. The current studies were aimed at identifying age-related limitations for processing temporal information using a variety of electrical stimulation parameters with the goal of identifying parameters that could mitigate the negative effects of age on CI performance. Studies 1 and 2 measured auditory temporal processing ability for non-speech signals at the single-electrode level for various electrical stimulation rates. Specifically, Study 1 measured gap detection thresholds, which constitutes a simple, static measurement of temporal processing. Study 2 measured amplitude-modulation detection thresholds, which utilized relatively more complex and dynamic signals. Peripheral neural survival was estimated on each electrode location that was tested in Studies 1 and 2. Study 3 measured phoneme recognition ability for consonant contrasts that varied in discrete temporal cues at multiple stimulation rates and envelope modulation frequencies. Results demonstrated significant effects of age and/or peripheral neural survival on temporal processing ability in each study. However, age and the degree of neural survival were often strongly correlated, with older participants exhibiting poorer neural survival compared to younger participants. This result suggested that a substantial reduction in peripheral neural survival accompanies aging in older CI users, and that these factors should be considered together, rather than separately. Parametric variation in the stimulation settings impacted performance for some participants, but this effect was not consistent across participants, nor was it predicted by age or peripheral neural survival.Item INVESTIGATING SOURCES OF AGE-RELATED DIFFERENCES IN WALKING MECHANICS(2019) Krupenevich, Rebecca Lynn; Miller, Ross H.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Walking is one of the most common activities of daily living and represents independence and improved quality of life, particularly among older adults. However, many older adults report substantial mobility challenges, which may be associated with age-related differences in lower-extremity gait kinetics. These differences are summarily referred to as a ‘distal to proximal shift’ of joint moments and powers, and are characterized by smaller ankle kinetics and larger hip kinetics in older vs. young adults. Although age-related differences in walking mechanics are well-documented, there is little consensus about which biomechanical factors contribute to these differences. Addressing this gap in knowledge is an important step in determining if this shift is preventable, or rather, an unavoidable part of healthy aging. Therefore, the overarching goal of this dissertation was to investigate sources of the age-related distal to proximal shift in gait kinetics. Specifically, this dissertation determined the extent to which the shift in kinetics is explained by age-related differences in (i) step length and trunk kinematics, (ii) years of endurance running (i.e., habitual physical activity), and (iii) gastrocnemius muscle architecture and individual lower-extremity muscle forces. In study 1, step length and trunk position did not reverse or reduce the age-related distal to proximal shift. Similarly, in study 2, a history of habitual endurance running did not reduce or reverse the shift. The third study confirmed the distal to proximal shift at the muscle level, suggesting that gastrocnemius may be a primary site of age-related differences in plantarflexor force, due to the shorter gastrocnemius muscle fascicles and smaller gastrocnemius force production in older adults vs. young adults. The present findings support the notion that the age-related distal to proximal shift of kinetics in active older adults is due primarily to differences at the muscle level and do not support previous speculations that this shift is due to spatiotemporal factors such as step length, joint kinematics, or physical activity. Further, these results suggest that age-related differences in lower-extremity joint kinetics are an unavoidable part of natural aging even in the absence of mobility limitations and the presence of a lifelong history of endurance running.Item A COMPARISON OF SEMANTIC CONVERGENCE IN YOUNGER AND OLDER HINDI-ENGLISH BILINGUAL SPEAKERS(2018) Sharma, Nisha; Faroqi-Shah, Yasmeen; Communication; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Semantic convergence offers support that the bilingual language system comprises a merging of two languages rather than the sum of two languages. This phenomenon has been studied in multiple language areas and in young children and adults. However, it is unclear how semantic convergence compares across grammatical class and across the lifespan. In this study, Hindi-English aging and adult bilinguals completed a word association task in response to verb and noun stimuli. Results showed that younger adult bilinguals experience more semantic convergence compared to older adult bilinguals, and that semantic convergence is greater for nouns compared to verbs. The results for word class are discussed in the context of the retrieval induced reconsolidation hypothesis, cross-language interference hypothesis, and weaker links hypothesis. The implications for aging are contextualized within the current research on aging and bilingualism.Item EFFECT OF ISOTHERMAL AGING ON SAC305 HARMONIC VIBRATION DURABILITY(2016) Lin, Elaine; Dasgupta, Abhijit; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The effect of isothermal aging on the harmonic vibration durability of Sn3.0Ag0.5Cu solder interconnects is examined. Printed wiring assemblies with daisy-chained leadless chip resistors (LCRs) are aged at 125°C for 0, 100, and 500 hours. These assemblies are instrumented with accelerometers and strain gages to maintain the same harmonic vibration profile in-test, and to characterize PWB behavior. The tested assemblies are excited at their first natural frequencies until LCRs show a resistance increase of 20%. Dynamic finite element models are employed to generate strain transfer functions, which relate board strain levels observed in-test to respective solder strain levels. The transfer functions are based on locally averaged values of strains in critical regions of the solder and in appropriate regions of the PWB. The vibration test data and the solder strains from FEA are used to estimate lower-bound material fatigue curves for SAC305 solder materials, as a function of isothermal pre-aging.Item The effects of sequence structure, age-related impairments, and Parkinson's disease on motor sequence learning(2015) Prashad, Shikha; Clark, Jane E.; Neuroscience and Cognitive Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Parkinson’s disease (PD) is a neurodegenerative movement disorder that affects over one million individuals in the US with approximately 60,000 new diagnoses every year. While characterized as a movement disorder, the effect of PD and aging on learning new motor skills has yielded equivocal results. Thus, the broad objective of this dissertation is to investigate the influence of PD on motor sequence learning. We begin by examining different sequence structures and how they are affected by age before investigating the effects of PD. To address the inadequacies of previous studies using fixed order sequences, we used probabilistic sequences, in which stimuli are linked by statistical associations. The first study directly compared the learning of probabilistic sequences to fixed sequences and randomly ordered stimuli in typical young adults (18-23 years) using a modified serial reaction time (SRT) paradigm. The results suggest that both fixed and probabilistic sequence groups exhibited learning, but the underlying learning processes were different in employing online and offline learning strategies. In the second and third studies, electroencephalography (EEG) was recorded from typical young adults (18-23 years), typically aging adults (55-75 years), and patients with PD (55-75 years) while they performed the same modified SRT task. We characterized the developmental landscape of 55-75 year old adults and found that cluster analysis separated typically aging adults into groups that provided a clearer understanding of their impairments. By unraveling movement and cognitive deficits and matching participants based on functional characteristics, we found that some typically aging adults and those with PD learned the fixed sequence, but not the probabilistic sequence, indicating age-related impairments in probabilistic motor sequence learning. We found cortical activations indicative of learning, even in the absence of behavioral indications suggesting that some adults may require more practice to learn the sequence, and possible compensatory mechanisms in patients with PD. Novel applications of these techniques prove effective for a deeper understanding of the dynamic motor learning process and provide evidence that impairments observed in patients with PD may be related more to the aging process than to Parkinson’s disease.Item The Effect of a 10 day Cessation of Training in Older Endurance Athletes on Pathological Production of Nitric Oxide and Reactive Oxygen Species Levels in Circulating Angiogenic Cells(2015) Corrigan, Kelsey J.; Hagberg, James; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cardiovascular disease (CVD) is a serious disease, and is the leading cause of death in the United States. Aging and physical inactivity are two well-established risk factors for CVD. Previous research has identified circulating angiogenic cells (CACs) as a novel risk factor for CVD. CAC number and function are affected by aging and exercise. Nitric oxide (NO) and reactive oxygen species (ROS) are intracellular compounds which can affect the health of the vasculature and are also affected by exercise. Endothelial nitric oxide synthase (eNOS) is responsible for NO production within the endothelium, and eNOS "coupling" is a phenomenon that plays a role in the balance between production of ROS and NO. The literature also indicates that NO can be produced in either a pathological or physiological capacity depending on which isoform of NOS produces it. NO and ROS have been previously measured in CACs and have been shown to affect in vivo and in vitro outcomes related to vascular function. Although NO, ROS, and CACs have all been studied in relation to exercise, no previous studies have examined how the cessation of training in older endurance-trained athletes affects these intra-cellular compounds through the eNOS-coupling pathway. The purpose of this study was to examine the effect of a 10-day cessation of exercise training in older endurance-trained athletes on ROS, NO and the eNOS-coupling pathway in CD34+ cells. NO and ROS were measured in isolated fresh CD34+ cells using fluorescent dye assays. The mRNA expression of genes involved in the eNOS-coupling pathway (endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), dihydrofolate reductase (DHFR), and guanosine triphosphate cyclohydrolase 1 (GTPCH1)) were measured using semi-quantitative Polymerase Chain Reaction (Semi-qt PCR). Flow mediated dilation was measured to gain information about endothelial function. No significant differences were detected after the cessation of training in CD34+ intracellular NO or ROS levels. Flow mediated dilation (FMD) also did not change significantly following cessation of training. eNOS mRNA expression was significantly lower following cessation of training but iNOS, DHFR, and GTPCH1 did not change. Taking into consideration the current literature, we expected to see changes in all of the above variables with the cessation of exercise training. There were several limitations present in our study, which could have affected our outcomes. Research in this area, specifically the eNOS coupling pathway, is still very new and this study shows that additional research is still needed to elucidate the underlying mechanisms in CACs.