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Differentiating Touch Epidermal Cells from Blood Cells in Single Source and Mixture Samples using Flow Cytometry
No full textBloodstains are a common piece of forensic evidence that can be found at crime scenes such as murders and sexual assaults. One factor that can complicate the analysis of bloodstains is the presence of epithelial cells within the same sample. Epithelial cells, particularly those transferred through skin contact, cannot be presumptively tested for and can create mixture DNA profiles that are difficult to interpret. Flow cytometry has the potential to provide probative information for biological samples that may contain ‘touch’ epithelial cells and/or blood because it is capable of determining morphological information such as the cell’s size and the components found within the cell. In order to determine if flow cytometry can differentiate touch cells from blood, single source touch cell and blood cell samples as well as mixtures were analyzed using flow cytometry to characterize autofluorescence profiles of individual cells. Single source samples were analyzed under with red, yellow, and green fluorescence. Profiles were then used to generate criteria for detecting each cell type in an unknown sample. The reliability of these signatures was assessed using a series of single source tissue samples and mixture samples. DNA analysis was also performed on mixtures to determine if the number of male blood cells in the overall sample corresponded with the A:Y ratio. Results showed that yellow and red fluorescent channels combined with a large cell gate (\u3e8,000) were best for differentiating single source blood and touch epithelial samples. However, it was still difficult to determine the presence of blood in the mixtures created. Results from DNA analysis showed that the A:Y ratio did not correspond to the expected mixture ratio particular at lower blood concentrations. Overall, this indicates that flow cytometry-based characterizations may be capable of differentiating touch cells from blood for some single source samples, but further research is needed to apply these signatures for mixture samples
Secondary Piano Studio Recital, video
No full textStudio Recital, videoSecondary Piano Studio Recital, videoWednesday, November 19, at 4:30 p.m.Recital HallJames W. Black Music Center1015 Grove Avenue | Richmond, Virgini
Junior Recital, Lauryn Jones, alto saxophone, video
No full textJunior Recital, videoLauryn Jones, alto saxophoneRussell Wilson, pianoMonday, November 10, 2025 at 6:00 p.m.Recital HallJames W. Black Music Center1015 Grove Avenue | Richmond, VirginiaThe presentation of this junior recital will fulfill in part the requirements for the Bachelor of Music degree in Music Education. Lauryn Jones studies alto saxophone with Dr. Sheri Oyan
Intergenerational Support and the Domestic Slave Trade, a Case Study: Chief Justice John Marshall and his Family
No full textThis thesis traces developments in how the family of Chief Justice John Marshall trafficked and traded enslaved people amongst themselves. I argue that kinship networks strategically bought, traded, loaned, and sold enslaved people to each other for the benefit of their extended families as a whole, a concept I have termed the inter-familial slave trade. I investigate these changes through the experiences of John Marshall, his sons, and grandsons, which reveal that marriage and death are two key moments of engagement in this trade, moments when families sought to secure support and inheritances that could help their heirs financially. By analyzing the Marshalls’ trafficking in people over the course of three generations, I demonstrate the specific ways that the inter-familial slave trade facilitated their financial planning and new household creation.
In addition, I discuss the Chief Justice’s jurisprudence in the context of his family’s economic investment in slavery and property rights. As Chief Justice, Marshall chose to bolster the future racial and financial supremacy of his children and extended family rather than interpret the law in ways that benefited the people they held in bondage. Bringing the extended family and the domestic slave trade together in one historical analysis allows for a nuanced yet wide-reaching interpretation of how an extended family network leveraged the value of their enslaved people to buttress familial wealth - and considering the Chief Justice’s legal impact regarding slavery, this family was more influential than most with regard to slavery
Small Molecule Approach to Modulate Class III Sirtuins
No full textSirtuins are class III histone deacetylases (HDACs) that utilize nicotinamide adenine dinucleotide (NAD+) as a cofactor to remove lysine acylations from histone and non-histone proteins, thereby influencing gene transcription and protein function. Here, we explored the modulation of two class III sirtuins, Plasmodium falciparum Sir2A (PfSir2A) and human SIRT5.
Plasmodium falciparum causes the most severe form of malaria in humans, maintaining persistent infection by antigenic variation, a mechanism regulated by PfSir2A. Here, we characterized the in vitro activity and steady-state kinetics of PfSir2A. Consistent with previous reports, PfSir2A preferentially removes long-chain fatty-acyl groups rather than acetyl groups from lysine residues. Interestingly, both activities of PfSir2A were activated by DNA supplementation. Through the repurposing of existing human sirtuin modulators, we identified nicotinamide riboside (NR) and 3-TYP as inhibitors of PfSir2A activity. Collectively, the mechanistic insights and inhibitors described in this study will facilitate the future development of PfSir2A inhibitors as antimalarial agents.
The second part of this project aimed at elucidating the basis of SIRT5 activation by NR using X-ray crystallography. SIRT5 is one of seven human sirtuin isoforms primarily localized in the mitochondria and heavily implicated in the regulation of metabolism. In our earlier studies, we showed the selective activation of SIRT5 deacetylase activity by NR. After several attempts to co-crystallize SIRT5 with NR, we only obtained apo-SIRT5 crystals. Nonetheless, this apo-SIRT5 reveals structural features of unliganded SIRT5, which can be further explored to identify druggable pockets to influence the rational development of a more selective and potent SIRT5 modulator
COPPER-BASED SURFACE-ENGINEERED MATERIALS FOR BIOMEDICAL AND CATALYTIC APPLICATIONS
No full textThis dissertation investigates the structure-property relationships in surface-engineered Ti-Cu sintered alloys for biomedical implants and Cu-Cr-O catalysts for chemical synthesis. Advanced multiscale characterization was employed to elucidate the mechanisms linking processing history to functional performance in these distinct material systems.
In the biomedical study, Ti-Cu alloys were fabricated from core-shell feedstock powders synthesized via high-power impulse magnetron sputtering (HiPIMS). Compared to blended elemental approaches, the core-shell approach yielded higher density and more uniform copper distribution after vacuum high-heating-rate sintering. These microstructural improvements significantly enhanced hardness and Young’s modulus while maintaining corrosion resistance comparable to commercially pure titanium. However, copper loss during rapid sintering limited antibacterial efficacy at short exposure times, identifying copper retention as a critical parameter for future optimization.
In the catalytic study, the thermal and chemical stability of copper chromite (CuCr2O4) was analyzed under reducing conditions. In situ X-ray diffraction and XPS revealed that the reduction of Cu2+ to active Cu0/Cu+ species initiates between 150 and 200 °C. A stable Cr3+ framework accommodates this reduction and redistribution of copper active sites. Additionally, the transient formation of the delafossite CuCrO2 phase was observed at intermediate temperatures, experimentally validating theoretical predictions regarding its electronic stability.
Collectively, this research establishes the microstructural and chemical mechanisms governing these systems. By integrating structural, mechanical, and redox analyses, this work provides rigorous design principles for optimizing engineered metallic biomaterials and oxide catalysts for demanding environments
Therapy-Induced Senescence in Cancer: Developing Senolytic-Based Combination Strategies to Delay Re-emergence of Triple-Negative Breast Cancer
No full textTherapy-induce senescence (TIS) represents a major biological outcome of many anticancer treatments and is increasingly recognized as a strategic vulnerability in triple negative breast cancer, which is a highly aggressive subtype with limited therapeutic options and frequent relapse. Here, we probed TIS as a primary cellular response that may ultimately compromise long-term outcomes using standard chemotherapeutic agents in TNBC as well as the antibody-drug conjugate sacituzumab govitecan (SG). Both chemotherapy and SG reliably induced pronounced senescence across TNBC models, yielding durable growth arrest, however, also generating a persistent reservoir of viable tumor cells capable of eventual proliferative recovery, a hallmark challenge of TIS. Senolytic treatments with ABT-263 (navitoclax) produced only a transient clearance of senescent cells across the treatments with doxorubicin, hydroxy-peroxy-cyclophosphamide, 5-FU, paclitaxel and gemcitabine. Platinum-based agents yielded senescent populations that appeared to be significantly more susceptible to sequential treatment combined with ABT-263. These findings indicate that whereas TIS can suppress the growth of tumors, it simultaneously creates a population of therapy-persisting cells that may fuel recurrence. Collectively, our data highlights TIS as a central, conserved treatment response across cytotoxic chemotherapy and also in an advanced targeted treatment approach, such as SG, which underscores the clinical challenge presented by senescent tumor cell survival. These studies further support the development of optimized senolytic combination strategies along with platinum compounds, potentially using safer Bcl-2/Bcl-xL inhibitors to enhance the clearance of TIS cells and improve long-term outcomes in TNBC
Constraints and mechanisms of Virginia barrier island migration in response to sea-level rise
No full textBarrier island migration is occurring in response to sea-level rise (SLR), yet upland vegetation feedback mechanisms remain underrepresented in prediction models. This study examines spatial and temporal patterns of marsh-to-upland conversion across barrier islands in the Virginia Coast Reserve (VCR) from 1984-2021 and characterizes ecological processes occurring on the marsh/upland boundary of Metompkin Island, Virginia. Thirteen Landsat images (~2-4 years apart) were classified into landcover classes (bare, grass, woody, marsh, ocean) and analyzed at the island and sub-island scale through landcover change matrices to calculate marsh-to-upland conversion rates, where upland includes bare, grass, and woody classes. Multiple regression analyzed the effect of the landcover composition and marsh/upland width on marsh-to-upland conversion. Field data from Metompkin Island, including vegetation cover and soil characteristics, were used to characterize the ecotone of the marsh/upland boundary. Landcover analysis revealed that marsh-to-upland conversion rates were spatially and temporally variable, but increased over time. Rates were consistently high across all transects and islands from 2016 2021, coinciding with an above-average frequency of major storms. At the sub-island scale, woody vegetation and upland width were negatively correlated with conversion, though these relationships were masked at the island scale. The influence of woody vegetation on migration appeared in top models during periods of lower relative marsh-to-upland change, indicating that the influence may be greater during periods of stability and reduced storminess. At the island scale, percent marsh-to-upland conversion, which controlled for island size, better revealed patterns of migration for smaller islands. At the marsh/upland boundary, vegetation and soil characteristics varied based on freshwater availability. These results will improve barrier island migration models that are important for conservation planning as islands face increasing development pressure, SLR, and more frequent and intense storms
FeCrAl and Cr-Coated Zircaloy-4 Surface Oxidation Chemistry After Short-Time High-Temperature Heating in a Steam Environment
No full textChromium (Cr)-Coated Zirconium (Zr) alloy and Iron-chromium-aluminum (FeCrAl) Alloys have been proposed as accident-tolerant fuel (ATF) cladding replacements for traditional Zr-alloy cladding. Previous research has been conducted showing higher oxidation resistances of Cr-Coated Zr and FeCrAl in air and some in a steam environment, but there is a present lack of studies that include a high heating rate, high temperature, low time, and quenching, which are crucial elements of certain accident scenarios. A testing apparatus with induction heating was used to simulate accident scenarios. Two coating methods for Cr-coated Zircaloy 4, powder vapor deposition (PVD) and cold spray (CS), and four FeCrAl Alloys, APMT, C26M, FA-SMT, and PM-C26M, were rapidly heated to high temperatures in a steam environment with a heating rate of 93°C/s. Targeting temperatures of 1200°C, 1300°C, 1400°C, and 1500°C were used, with a 1min hold time, followed by quick quenching in water. PVD samples showed an evolution of a protective chromia layer from 1200°C to 1400°C, and CS samples showed a similar evolution from 1200°C to 1300°C. APMT samples showed a small protective Al2O3 oxide layer formed between 1200°C and 1300◦C, along with a surface layer of chromia. C26M, FA-SMT, and PM-C26M samples all showed a thin protective Al2O3 oxide layer at the surface from 1200°C to 1300°C. All FeCrAl and cold-spray samples failed to survive beyond 1400◦C and burst before reaching the target temperature. PVD failed to reach 1500◦C and burst before a stable temperature was achieved
Toward Wholeness and Freedom: A Holistic Exploration of Choice-Based (Art) Education Across TAB, Montessori, and Reggio Emilia
No full textThis qualitative multi-case study examines how choice-based (art) education is philosophically grounded, theoretically framed, and practically enacted across three student-centered educational approaches: Montessori education, Reggio Emilia education, and Teaching for Artistic Behavior (TAB). Drawing on classroom observations, interviews, and pedagogical artifacts from three experienced educators, the study investigates how student choice operates within different educational ecosystems and explores the holistic value of choice-based education from a comparative perspective.
Guided by two research questions, the study first analyzes how choice-based (art) education manifests similarly and differently across the three approaches in their philosophical, theoretical, and practical dimensions. The findings present contextual descriptions of each case and illustrate the mechanisms of choice through selected empirical examples. Comparative analysis reveals a fundamental distinction between approaches grounded primarily in individual choice (Montessori and TAB), reflecting subjectivity, and those grounded in communal choice (Reggio Emilia), reflecting intersubjectivity. At the same time, the approaches share notable similarities, including educators’ facilitative roles, carefully prepared environments that support freedom of movement, the coexistence of independent and collaborative learning, attentiveness to students’ readiness and “comfort zones,” and the enactment of choice as an ethical responsibility.
To address the second research question, the study adopts a holistic interpretive lens informed by holistic education theory and Taoism. Through this lens, the three approaches are interpreted as distinct yet convergent efforts to align educational practice with natural processes of human development, learning, and creating. This alignment manifests through environment design, student-centered curricula, and pedagogies grounded in trust in students’ inherent capacities