Dissertation Defense Announcements

Abstract: The overrepresentation of African American males at risk for academic challenges and special education services, disciplinary actions, dropout rates, and incarceration is an alarming trend in the United States that has been ongoing for over 40 years. Research has shown correlation exists between a teachers’ cultural competence and a students’ positive academic and behavioral outcomes (Boutte & Hill, 2006; Howard & Terry, 2011; Rychly & Graves, 2012). However, many teachers are inadequately prepared with appropriate content knowledge, experience with culturally relevant practices, and training to address culturally and linguistically diverse students’ learning needs (Sobel et al., 2011). A cultural learning gap between teachers and students, along with, inadequate preparation can limit the choices of effective culturally responsive practices. An educator’s beliefs, attitudes, and expectations can have a major impact on student outcomes. (Ladson-Billings, 2006). Culturally responsive teachers understand the impact culture has on the educational system and place culture at the center as they investigate techniques needed for improving the performance of underachieving students of color (Bonner et al., 2018). The aim of this study was to examine perceptions of high school African American males receiving special education services or at risk for academic challenges related to teacher responsiveness to cultural diversity. This study used a phenomenological qualitative method to gain insight into the lived experiences of African American males. Findings, limitations, suggestions for future research, and implications for practice will be discussed.

A supercritical carbon dioxide (sCO2) Brayton power cycle is considered as one of the promising energy conversion systems for a number of applications such as Concentrated Solar Power (CSP) plants due to its high thermodynamic efficiency and small equipment size. The compact heat exchangers such as Printed Circuit Heat Exchangers (PCHEs) with micro-channel geometry are suitable for coupling different heat sources to a sCO2 Brayton power cycle. The objective of this study is to design and optimize an advanced PCHE micro-channel geometry and topology for a sCO2 Brayton cycle. This work is concerned with the design where both sides of the plate are etched forming a double-etched micro-channel design configuration. In this advanced micro-channel topology, shim plates are needed to construct a PCHE stack using diffusion bonding.
Thermo-hydraulic performance of semi-circular micro-channel and advanced semi-circular and circular double-etched micro-channel geometries, and maximum stress, were determined. The results obtained for the advanced double-etched microchannel geometry were compared to the “conventional” semi-circular single-etched (single-side etched) micro-channel design for the counter-flow arrangement. Using ANSYS-Workbench, a multi-objective optimization algorithm employing NSGA-II and Response Surface Approximation (RSA) as a surrogate model was used for design and optimization of the advanced double-etched micro-channel PCHE geometry.

Cancer is one of the most common causes of mortality in homeless adults. When a homeless person is hospitalized, they typically return to the streets, making recovery difficult. Conducting a needs assessment survey of homeless patients who are newly diagnosed with cancer was the first step towards evaluating how they can receive safe and cost-effective healthcare. Collection of information was from three perspectives: the patient, the oncology provider, and costs. Nine qualitative interviews with homeless individuals focused on concerns and barriers to care. Ten qualitative interviews with Medical Oncologists as well as a 20 question Survey Monkey was sent to all providers and focused on current treatment of their homeless patients. Lastly, a retrospective cost analysis examined costs of inpatient and outpatient care during chemotherapy. Two themes emerged from the patient interviews: Barriers to care and Someone to help. Three themes emerged from the oncology interviews: I worry about everything, Making decisions, and Care after chemotherapy. Half of the 19 providers who responded to the Survey Monkey questions indicated that they would revise treatment plans because of homelessness. All providers stated they would utilize a housing first option if available for their homeless patients. The retrospective cost analysis of 53 homeless patients with cancer over a 5-year period showed cost savings from inpatient vs outpatient treatment which totaled $9.0 million dollars. Drawing up a proposal to share with stakeholders is needed to develop a plan to help this population which may include a housing first/respite home as a solution.

The correct folding of proteins after synthesis and stress-promoted denaturation is critical for cell viability in all organisms. The Hsp70 molecular chaperone is a key player in proteostasis, deciding which proteins are foldable and which are too badly damaged and need to be targeted for degradation. Hsp70 plays an important role as a drive of cancer, stabilizing key mutated oncoproteins such as HER2, p53, RNR, SHR and MUC1. This importance of Hsp70 in basic cell functions as well as human illness prompted us to examine novel ways to characterize Hsp70 genetic and physical interactors. In this thesis, we decided to tackle three main roadblocks in studying chaperone interactions; 1) purification of chaperone complexes at native stoichiometry in mammalian cells, 2) understanding the roles of co-chaperones in cancer 3) teasing apart bridged vs direct chaperone interactions. To solve the issue of native stoichiometry purification, we have utilized CRISPR-Cas9 genome engineering to insert epitope tags into the N-terminus of Hsp70 in mammalian cells. This tagged chaperone is present as the only Hsp70 in cells, is stable without the use of any selectable marker and allows expression of Hsp70 at native levels. To understand co-chaperone function in cancer, we used a novel chemogenomic screening technology on WT and DNAJA1 knockout HAP1 cells. In doing so, we have uncovered a dependence of a large proportion of approved oncology drugs on DNAJA1 status. Finally, we have used cross-linking mass spectrometry to define for the first time the direct interactors of Hsp70 in yeast. Our data reveals a wealth of information of fundamental Hsp70 function including discovery of active Hsp70 dimers, client binding throughout Hsp70 and a huge number of novel PTM-associated Hsp70 interactions. Overall, aside from gaining fundamental insight into the workings of Hsp70, this thesis provides a roadmap and tools for the chaperone community to explore novel biologically relevant Hsp70 interactions.