26419 research outputs found
Sort by
Mitochondria-mediated Epigenetic Transfer Between Chondrosarcoma and Wild-Type Cells
No full textGlioblastoma (GB), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), cholangiocarcinoma, and chondrosarcoma (CS) cancers all contain mutations in the gene isocitrate dehydrogenase 2 (IDH2). The mutant IDH2 enzyme exhibits transformation of alpha-ketoglutarate (αKG) into the oncometabolite D-2-hydroxyglutarate (D2HG) in the mitochondria of these cancers. Mitochondrial-mediated transfer between cancer cells and recipient cells is a significant event that impacts the physiology of the receiving cell, specifically the epigenetic landscape. Previous experiments indicating increased DNA methylation in mesenchymal stem cells exposed to IDH1 or IDH2 conditioned medium underscore the potential role of D2HG to alter methylation states. Additionally, the presence of nanotubular highways facilitating mitochondrial exchange between IDH2 mutant chondrosarcoma cells further motivates investigation into mitochondria-mediated epigenetic transfer. I hypothesize that mitochondria derived from IDH2-mutant chondrosarcoma cells are transferred to recipient normal lymphoblastoid B cells (N-LCL) primarily through tunneling nanotubes (TNTs), and that disruption of the actin cytoskeleton will inhibit this transfer. Secondly, the presence of D2HG generated in the mitochondria due to IDH2 mutations will lead to increased levels of mitochondrial DNA and RNA methylation. Cell physiology is expected to be affected by this genetic alteration in both host and recipient cells. Thirdly, transcriptional downregulation will be triggered by D2HG-mediated methylation of DNA and histones. My specific aims are 1) Quantify the exchange of mitochondria via nanotubular highways between IDH2 mutant cells and wild-type cells and control transfer via cytoskeletal inhibitors, 2) compare extent of variation of D2HG accumulation in mitochondria segregated from IDH mutant cells and wild-type chondrocytes and 3) characterize methylation patterns of mitochondrial DNA and RNA between mutant cells and wild-type counterparts. The experimental data acquired here will reveal a better understanding of the molecular mechanisms behind the progression of IDH2 cancers and make advancements in our understanding of intercellular communication in cancer biology
Two Essays on Customer Loyalty
No full textCustomer loyalty is vital for business success, yet most research treats loyal customers as a uniform group. This essay challenges that assumption by proposing that attitudinally loyal customers are psychologically heterogeneous. Drawing on Construal Level Theory (CLT), I introduce the construct of Consumer-Brand Construal Level (CBCL) to distinguish loyal customers based on how abstractly or concretely they construe their brand relationships. I conceptualize two loyalty mindsets, macro-loyalty (abstract, big-picture) and micro-loyalty (concrete, detail-focused), and argue that even highly loyal consumers differ meaningfully in their CBCL. I develop and validate a new CBCL scale (Studies 1–2) and then test how these mindsets predict key loyalty outcomes across five additional studies. Findings show that macro-loyal consumers display deeper loyalty and greater resistance to switching, consistent with predictions. However, for willingness to pay a premium, responses to brand transgressions, and reactions to cross-selling vs. upselling, extremely loyal consumers often showed patterns opposite to expectations. When loyalty reached very high levels, a macro mindset no longer produced the anticipated benefits and sometimes reversed direction. These results identify boundary conditions of loyalty segmentation and suggest that extreme loyalty may involve distinct psychological processes. Overall, the research offers a more nuanced view of loyalty and provides theoretical and managerial implications for tailoring strategies to different loyal customer mindsets.
The second essay explores an understudied emotional driver of consumer–brand relationships: boredom. Boredom is a common yet understudied emotion in consumer research, particularly in relation to its role in shaping consumer–brand relationships. Drawing on meaning-regulation theories, this research proposes that boredom, especially the type characterized by a perceived lack of meaning, can orient consumers toward brands as potential sources of psychological restoration. I theorize that consumers experiencing meaning-deficit boredom are motivated to seek psychological restoration by turning to brands they perceive as meaningful. Specifically, I test the hypotheses that boredom increases brand loyalty (Studies 1), that this effect is mediated by consumers’ motivation to search for meaning (Studies 2a and 2b), and that boredom proneness predicts greater loyalty propensity through chronic meaning-seeking (Study 3). I also investigate whether bored consumers respond more positively to meaningful brand messages (Study 4), whether engaging with a loyal brand can reduce state boredom (Study 5), and whether brand-specific attachment avoidance moderates the effect of boredom on brand loyalty (Study 6). Empirically, the findings provide mixed but theoretically informative evidence. Experimental manipulations of state boredom did not consistently produce the predicted increases in loyalty, and some effects emerged in the opposite direction. However, study 3 offers clear support for the proposed mechanism, showing that boredom proneness predicts higher loyalty propensity indirectly via chronic search for meaning, and several supplementary patterns, such that loyal-brand engagement can buffer against boredom, converge with the theorizing. This research introduces boredom as a novel, if bounded, antecedent of loyalty and positions brand loyalty as a potential psychological coping mechanism that can help consumers regulate meaning, while also clarifying important boundary conditions for when such effects are likely to emerge
Reflections in the Mirror: An Examination of Racially Congruent Mentoring of Black Teacher Candidates in a Teacher Education Program
No full textThe high demand for Black educators in K-12 schools across the United States has caused several teacher training programs to rethink how they prepare Black teacher candidates for the teaching workforce (Andrews et al., 2019; Blazar, 2024; Milner & Howard, 2004). Improving teacher candidate training, especially for Black teacher candidates can boost K-12 Black teacher representation. Literature on Black teacher candidate’s experiences while being mentored identifies several challenges that include issues with implicit bias, microaggressions, stereotyping and other occurrences of racial discrimination (Daly et al., 2024; Hampton et al., 2008; Kardos & Johnson-Moore, 2010; Rodriguez et al., 2020). The process for pairing Black teacher candidates with mentor teachers requires intentionality and implementation. Black mentor teachers can help Black teacher candidates strengthen Black teacher identity and invalidate implicit biases that impact their professional and personal development (Darling-Hammond, 2010; Kohli et al., 2022; Wandix-White, 2020).
This qualitative study examined the racially congruent mentoring relationships between Black teacher candidates and their Black mentor teachers. Using a narrative inquiry approach, this study explored the lived experiences of study participants in three key areas: sense of belonging, negating implicit bias, and Black teacher identity. Findings from this study indicate that racially congruent mentoring relationships for Black teacher candidates positively impact their sense of belonging. Additionally, the mentoring relationships fortify Black teacher candidates’ ability to negate implicit bias and assist in developing stronger Black teacher identity
Who Gets to Lead? Policy, Systemic Barriers, and Leadership Norms in Education
No full textThis phenomenological qualitative study investigated the underrepresentation of women and racially marginalized individuals in the superintendent position, the highest leadership position within K-12 public education. The superintendent position has been overwhelmingly represented by males, even though women were the majority of the teaching workforce. Grounded by institutional theory and viewed through a phenomenological lens, I examined how organizational norms, hiring practices, and access to mentorship contributed to and upheld systemic barriers to the superintendent position. Through exploring the interpreted lived experiences of current female superintendents across public school districts that reflected the national patterns, this research addressed the disparities in leadership pathways. Institutional theory offered a lens for examining how established leadership pathways replicated hiring patterns and reinforced systemic barriers. Using phenomenological research, the study revealed how historical norms, biases, and structural inequities impacted the advancement of diverse leaders into high-level positions. By understanding the experiences of sitting female superintendents from public school districts, I propose actionable, evidence-based strategies, including mentorship programs, transparent hiring practices, and leadership development targeted to underrepresented individuals. The findings aimed to inform school district policy reforms and reshape institutional practices that continue inequities, resulting in a more inclusive and effective educational leadership career pathway
Exploring Student Confidence and Calibration Accuracy in College Algebra: A Mixed-Methods Explanatory Sequential Study
No full textCalibration, or students’ ability to predict and postdict their performance on an academic task, has important implications for academic performance. It can influence students\u27 decision making processes concerning learning activities, as well as their levels of motivation and self-regulation (Kolovelonis, 2023). The literature on calibration is clear, often indicating that students are not great at these judgements (Lin et. al, 2001). While this phenomenon is well documented, it is not an easy one to explain. Therefore, a two-phase explanatory-sequential mixed method design was used to examine undergraduate students’ calibration judgements on a college algebra exam. To further contribute to the literature, a key goal of the present study was to conduct one on one video recorded interviews to gain additional insights into students’ rationale for their calibration judgements. Quantitative findings indicated that higher achieving students were more accurate in their predictions; whereas lower achieving students were less accurate and tended to overestimate their performance. There were no significant differences in postdiction accuracy. These are both robust patterns of results (e.g., Hacker et al. 2000; Bol & Hacker, 2012). Qualitative results from follow up interviews revealed that students across achievement levels commonly experienced math related anxiety and stress particularly in testing situations. Students often based their confidence on emotions such as anxiety, doubt, or optimism rather than clear evidence of performance. These results underscore the complex interplay between emotion and self-awareness in students’ confidence judgments and calibration accuracy
Marginalized Pre-Service Teachers’ Digital Competence: An Exploration of Epistemic Beliefs and Lived Experiences
No full textAmid growing calls for equity in teacher education, this dissertation investigates how digital competence and epistemological beliefs interact within the lived experiences of marginalized pre-service teachers (mPSTs), also referenced as teacher candidates, whose racial and ethnic identities often position them at the periphery of dominant educational narratives. Anchored in critical narrative inquiry (Pino Gavidia & Adu, 2022) and framed by the DigCompEdu digital competence model (Redecker & Punie, 2017), the study employs a multimethod approach, integrating quantitative data from the SELFIEforTEACHERS self-assessment tool (Economou, 2023) with qualitative insights drawn from in-depth narrative interviews. The participant cohort consists of 50 marginalized pre-service teachers enrolled at a Historically Black College or University (HBCU) teacher preparation program. Three research questions guide this study: (1) What are the levels of marginalized pre-service teachers according to the DigCompEdu framework? (2) What are marginalized pre-service teachers’ epistemic beliefs about digital competence? and (3) What lived experiences influence marginalized pre-service teachers’ epistemic beliefs about digital competence?
Quantitative findings indicate that most participants exhibit “Explorer”-level digital competence, with notable variations across domains such as assessment, empowering learners, and facilitating digital literacy (Seyferth-Zapf, 2024; Mizova et al., 2025). The qualitative analysis, guided by critical narrative methods (Pino Gavidia & Adu, 2022), reveals recurring themes of self-taught digital learning, evolving emotional dispositions toward technology, and the formative influence of early access gaps and sociocultural misrecognition on teacher identity and epistemic development (Leonardo, 2013; Heath & Segal, 2021).
By situating mPSTs’ epistemic beliefs within sociocultural and institutional contexts (Hofer, 2001; Bandura, 1989), this study challenges dominant paradigms in teacher education that often neglect the nuanced digital realities of marginalized communities. The findings underscore the need for culturally sustaining pedagogies and equity-oriented frameworks in teacher training, professional development (Fraser, 2008; Jackson et al., 2024), and technology integration, offering evidence-based recommendations to address the digital divide not only as a matter of access but as a multifaceted issue of recognition, redistribution, and epistemic agency
Development of a Niobium Multicharged Ion Beamline
No full textA laser-driven multicharged ion beamline has been developed, incorporating electrostatic components for acceleration, beam shaping, focusing, and selection by ion charge and energy per charge. A 10 ns, 1064 nm Q-switched Nd:YAG laser, operated at a fluence of 68 J/cm², ablates a Nb target to generate a plasma from which ions are extracted and accelerated. After ion acceleration, a five-element electrostatic lens is used to reduce the beam size and collimate the ion beam, thereby maximizing ion transmission through subsequent beamline components. A 90 ° cylindrical electrostatic ion energy analyzer is used to select ions within a specific energy per charge range. Further analysis of ion energy per charge is conducted using a three-grid retarding field analyzer. Ion signals are detected via time-of-flight measurements using a Faraday cup. Ion charge selection is achieved using a pair of pulsed deflection plates. The ions are subsequently focused by two einzel lenses, one to reduce the beam size and the other to further focus the beam. Ion pulses of Nb³+ to Nb⁸+, containing approximately 10⁷ to 10⁸ ions per each ion charge, were measured at the Faraday cup location, with ion counts decreasing as the charge state increased. This ion beamline enables ion acceleration, beam shaping, and the selection of charge states and energy ranges, supporting applications such as ion deposition and implantatio
From First-Generation to Flourishing: Exploring the Influence of Academic, Social, and Deeper Life Interactions in Higher Education
No full textDespite comprising half of all undergraduate students (RTI International, 2024) and being widely studied in higher education literature, first-generation students experience many barriers to success and are less likely to graduate than continuing-generation students (Engle & Tinto, 2008; Fry, 2021; Kezar et al., 2023). Social science and higher education scholars have identified flourishing, the presence of complete mental health and holistic well-being (Keyes & Haidt, 2003), as an important outcome of higher education beyond more traditional success metrics, with the thought that flourishing promotes success in other areas.
This study explored how first-generation students’ academic, social, and deeper life interactions influenced their experience of flourishing. Deeper life interaction represents a recent contribution to higher education scholarship involving interactions around meaning, values, and purpose (Sriram et al., 2020a; Sriram & McLevain, 2016) that are not encapsulated in traditional social and academic interactions (Tinto, 1993). Data was collected via The Academic, Social, and Deeper Life Interactions Instrument (Sriram et al., 2020a) and The Flourishing Scale (Diener et al., 2009) and analyzed via structural equation modeling (SEM) to determine how first-generation students’ academic, social, and deeper life interactions with their peers, faculty, and staff predicted their flourishing. Participants included 309 undergraduate students (N = 112 first-generation students) from a public, state university on the east coast.
The final structural equation model indicated acceptable fit [χ2 = 467.088 (df = 199, p \u3c .001), CFI = .939, RMSEA = .066, SRMR = .0944] and explained 20.4% of the variance in flourishing for first-generation students. Social Interactions with Faculty/Staff – Greetings (SIFSG) (β = .287), Social Interactions with Peers (SIP) (β = .263), and Deeper Life Interactions with Peers (DIP) (β = .067) had the strongest impact on first-generation students’ flourishing. Recommendations for future practice include: (1) creating opportunities for social interactions between students and their peers, faculty, and staff; (2) developing avenues for social and academic interactions to lead to deeper life interactions in classroom and co-curricular settings, including student organizations, programs, and residence halls; and (3) assessing how students’ interactions with others in and out of class are contributing to their flourishing throughout college
Valorizing Cement Kiln Dust and Glass Powder: A Binder Study on Sustainable Partial Cement Replacement
No full textThe production of cement ranks as a major source of global CO₂ emissions because of the high energy requirements needed to create clinker. The construction industry is actively seeking ways to reduce its carbon footprint. Utilizing industrial waste materials to partially replace cement can lower emissions. This research evaluates a ternary binder system which uses Cement Kiln Dust (CKD) and Glass Powder (GP) to replace a portion of Type IL (Portland Limestone) cement. The mixes were made with a fixed water-to-binder ratio of 0.44 and contained 15% GP by mass while the CKD content ranged from 0% to 10%. The fresh paste properties were tested using ASTM C1437 flow tests and ASTM C191 setting-time measurements. Hardened state performance was determined by ASTM C109 compressive strength tests on 50 mm cubes at 7 days for all mixes and 28 days for specific mixes. The microstructural development was studied using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction (XRD).
The addition of GP resulted in a 12.5% increase in flow and a 35-minute reduction in initial setting time when compared to the 100% cement control. The addition of CKD up to 5% maintained workability but resulted in an additional 185-minute reduction of initial set time; higher CKD amounts (≥ 7%) caused paste stiffening and excessive setting acceleration. The mix containing 5% CKD and 15% GP (IGC 4) showed the highest 28-day compressive strength of 31.89 MPa among all CKD-containing blends because it achieved an optimal combination of filler, pozzolanic, and alkali-activation effects. The FTIR spectrum of IGC 4 showed increased Si–O–Si and O–H band intensities, and XRD analysis demonstrated a wider amorphous hump together with reduced portlandite peaks which indicated better C–S–H formation and less residual lime.
The research shows that combining approximately 5% CKD with 15% GP produces a low-carbon binder which preserves workability and speeds up setting and maintains mechanical strength thus providing a sustainable method to utilize landfill kiln dust and waste glass
Effect of Moderate Decrease in Contractility on Epithelial Cell-Cell Contacts Under External Stretch
No full textEpithelial tissues are characterized by extensive cell–cell contacts and often subject to stretch during normal function. Cell-cell contact adhesion strength maintains mechanical continuity from cell to cell. Mechanical forces exerted by cells via actomyosin contractility are known to strengthen cell-cell adhesions to a certain extent. While it is known that a large decrease in contractility causes cell-cell contact rupture due to weakened adhesions, it is unclear how a moderate reduction in contractility affects cell-cell junction stability. Here, we studied how a moderate inhibition of non-muscle myosin II (NMII) affects the integrity of epithelial cell-cell contacts, especially when subject to the challenge of mechanical stretch. We first modulated the contractility of epithelial cell islands strongly, or moderately, using the NMII inhibitor blebbistatin. Strong inhibition severely disrupted the actin cytoskeletal structure and induced widespread cellcell contact rupture while moderate inhibition did not. We then used traction force microscopy to show that while strong inhibition of NMII nearly abrogated the contractility, moderate inhibition led to only a moderate reduction in cell-exerted forces. Then, we subjected cell islands with moderate contractility reduction to external stretch of over 30% to ascertain how cell-cell contact integrity was affected. Surprisingly, we found that moderate contractility reduction decreased the level of cell-cell contact ruptures due to stretch. Nanoindentation experiments revealed a significant reduction in cell Young’s modulus following moderate contractility inhibition. Thus, under external stretch, stretch-induced forces are also expected to be lesser when contractility is moderately reduced. Our results can be understood with the following framework: Under normal conditions, epithelial cell-cell contact adhesion strength exceeds the forces generated by cellular contractility. External mechanical forces (e.g., due to biaxial stretch) additionally stress junctions and lead to contact rupture. When contractility is moderately reduced, both internal tension and stretch-induced forces are lowered, with this reduction exceeding any reduction in adhesion strength. Thus, overall junctional integrity is enhanced under a moderate decrease in contractility. We propose that our findings have important implications to understand processes such as morphogenesis, wound healing, and regeneration, where epithelial cells spatiotemporarily modulate their contractility