UBIR Repository (Univ. at Buffalo)
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Non-Intrusive Laser Absorption Diagnostics for Combustion Environments
No full textPh.D.Laser absorption measurements have seen widespread use as a combustion di-agnostic. Benefits over intrusive probes include high sampling rate, high detectabilityand signal-to-noise ratio, direct results from first principles, multiple gas propertymeasurements from a single laser, and the non-intrusive nature of the measurement.These sensors have been applied to a wide variety of combustion applications rangingfrom simple burners and combustion engines, up to hypervelocity scramjet combus-tion chambers.Methods for analyzing direct absorption spectroscopy measurements for lowpressure or isolated-feature spectra are well established. For many combustion ap-plications, however, the gas pressure is high and the features in the absorption spec-trum are sufficiently blended to make the determination of gas properties difficult.A method for determining the gas concentration from blended absorption featuresusing direct absorption spectroscopy is developed in this study.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Copper Nanowire Synthesis and Coating with Metal-Organic Framework ZIF-8
No full textM.S.Copper nanowires can be used in many different areas, such as sensors, solar cells, and catalysts, based on their high thermal and electrical conductivity and catalytic activity for particular reactions. The conventional materials for transparent conductive films are indium-doped tin oxide (ITO) and silver nanowires, but ITO is brittle and silver is relatively expensive. Copper nanowires synthesized via solution-phase methods have potential for use in the next generation of low-cost flexible transparent conductive films. Here, we report a low-cost and high-yield aqueous synthesis of high aspect-ratio copper nanowires using L-ascorbic acid as a reducing agent and oleylamine as a capping agent. The diameter and the aspect-ratio of the copper nanowires were found to depend upon the amount of surfactant used as well as on the amount of reducing agent used. Effects of various reaction parameters, including temperature and reaction time on aspect-ratio and yield of copper nanowires were also evaluated. The copper nanowires synthesized here were typically 10-20 nm in diameter and 5-10 µm in length. In addition, we explored the preparation of core-shell copper nanowire@ZIF-8 nanocomposite structures, in which the metal organic framework (ZIF-8) is deposited on the copper nanowires. We report a simple preparation method of CuNW@ZIF-8 nanocomposite via solution-phase synthesis using 2-methyl imidazole and zinc nitrate hexahydrate as precursors for ZIF-8. Characterization techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD) were used to demonstrate the successful synthesis of core-shell structure. The CuNW@ZIF-8 nanocomposite has potential application as a gas storage material. Incorporation of the copper nanowires into ZIF-8 or other MOFs could dramatically increase their thermal conductivity, and therefore the rate at which they could adsorb and desorb gases.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Intelligent Group Structuring for Mass Collaboration within Engineering Design
No full textPh.D.Collective reasoning is an inherent trait in human behavior as a means to advance society. This behavior is exemplified in mass collaboration within the design engineering process as it supports the inclusion of unique perspectives when working on complex problems. Increasing the number of individuals providing input and support into design challenges can increase innovation, decrease product development times and provide solutions that truly encompass the needs of the market. Along with these benefits, many challenges arise to fully capitalize on the collective efforts of individuals. One of the greatest challenges in applying mass collaboration to the engineering of solutions is the organization of individuals within large design efforts. This dissertation approaches the problem of organization with a continually narrowing level of detail. To begin, a top-level overview of a simulated design process is studied with a primary focus being placed on the network structure of interconnected groups. Next, the scope is narrowed by transitioning the focal point to simulated groups of multi-disciplinary engineers. Two frameworks are developed focusing on the optimal network structure of groups with respect to their communication trends, and the recommendation of individuals for projects to which the impact of their efforts would be maximized. Finally, the scope is tightened once more, as both individuals and design challenges are studied for their competency distribution and semantic makeup, allowing for more accurate and rigorous adhesion to optimal design network structural requirements.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Utilization of Lyso-Phosphatidylserine Nanoparticles to Reduce Immunogenicity and Improve Clinical Utility of Acid Alpha-Glucosidase in the Treatment of Pompe Disease
No full textPh.D.Pompe Disease is an autosomal recessive disease that is characterized by a mutation in the GAA gene, encoding the production of the enzyme acid alpha-glucosidase (GAA). Residing in the lysosome of healthy cells, GAA is responsible for the catabolism of glycogen into glucose, critical molecules for basic cellular function. In the absence of GAA, glycogen accumulates in the lysosome and leads to impaired cellular function, eventually resulting in muscle fatigue, hypotonia, cardiomegaly, and eventually cardiac and respiratory failure. The first line of treatment for Pompe Disease is recombinant GAA (rhGAA) that is administered via intravenous infusion every two weeks. While effective, virtually all patients (89-100%) receiving rhGAA eventually develop anti-rhGAA antibodies that severely inhibit the activity of the protein, leaving the patient with no relief from therapy. Once antibodies develop, patients typically die within 12-18 months, and with no alternative therapies, the circumstances are dire for these patients. Previously, our lab has harnessed the biological function of phosphatidylserine (PS) to develop a subcutaneous immunotherapy 'reverse vaccination' strategy that has shown to be effective at preventing antibody development against therapeutic proteins such as Factor VIII (FVIII) and rhGAA. PS is a naturally occurring anionic phospholipid that is present on the inner leaflet of cell membranes. When cells undergo apoptosis, PS flips to the outer membrane and signals to circulating macrophages and resident dendritic cells to engulf the cellular debris in a tolerogenic manner. The presence of PS on the membrane of the cellular debris initiates a signaling cascade resulting in removal with no immune response. We have shown that through subcutaneous administration of antigen in the presence of PS, we can reduce the generation of antibodies against the protein by converting it from an immunogen to a tolerogen. Further experiments in our lab have shown that PS-mediated tolerance induction is modulated by tolerogenic dendritic cells that secrete anti-inflammatory cytokines such as TGF-β, initiate the generation of regulatory T-cells, and inhibit memory B cell production. The overall aim of this dissertation is to advance our knowledge of PS mediated tolerance induction and advance our ‘reverse vaccination’ towards clinical translatability...Overall, this dissertation has harnessed a unique property of PS and shown that tolerance can be induced to rhGAA orally, potentially solving a major medical need. We developed an improved nanoparticle containing Lyso-PS, showing oral administration as an effective tolerance induction method, and we identified supplementing rhGAA administration with oral Lyso-PS-rhGAA as a highly effective method of tolerance induction that does not interfere with clinical rhGAA dosing. Further, we suggest that Lyso-PS-rhGAA can operate as a standalone therapy, showing similar efficacy as free rhGAA, with reduced immunogenicity. This dissertation highlights the use of Lyso-PS nanoparticles to reduce immunogenicity of rhGAA and be an effective therapy, addressing an unmet clinical need for Pompe Disease patients.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Density Functional Theory (DFT) Studies of Hydrogen Rich Materials, Methylammonium Lead Bromide Perovskite and Silicon Dioxide Under Pressure
No full textPh.D.Density functional calculations coupled with evolutionary crystal structure searches are carried out to study high pressure solid state systems. The first part of this dissertation focuses on explore the high pressure potential energy surface and the superconductivity of hydrogen rich materials. In the second part, structural analysis, molecular dynamics, and electronic calculations are performed on MAPbBr3 and SiO2 phases to provide explanations to experimental results.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
A Three-Study Investigation into the Influence of a Teacher Residency Model for Literacy Teacher Preparation: Does a Residency Provide an Advantage?
No full textPh.D.This dissertation is A Three-Study Investigation into the Influence of a Teacher Residency Model for Literacy Teacher Preparation: and asks the question, Does a Residency Provide an Advantage? Study 1 provided exploratory findings with a mixed-methods approach, which led to further examination of the literature in Study 2. In response to the literature gap of comparative examinations of traditional and residency model teacher preparation for literacy instructional ability, Study 3 was designed. Study #1: Student Teachers of Literacy in Different Preparation Models: Does a Teacher Residency Provide an Advantage?, is a parallel mixed methods study that explored self-efficacy and competence for literacy instruction among student teachers (STs) in three models of teacher preparation, including a residency model. Qualitative interviews were conducted with STs, mentor teachers, and supervisors. Quantitative data were collected using a pre-/post-survey design using the Teachers' Sense of Efficacy for Literacy Scale (TSELS). Mentor teachers and supervisors completed a modified TSELS on STs' abilities. Data were analyzed using meta-inferences between strands. Results revealed Residency Model STs held higher levels of self-efficacy for literacy instruction. Mentor teachers and supervisors reported Residency Model STs outperformed other models. Study #2: Literature Review: A Textual Narrative Synthesis on Teacher Residencies from Studies Published between 2014-2019, revealed that although teacher residency programs (TRPs) are increasing in prevalence in teacher preparation, the scholarly literature on these programs has not been systematically synthesized to demonstrate consensus on the benefits of teacher residency programs for teacher preparation over traditional models. This literature review provides a textual narrative synthesis of empirical research studies on teacher residencies from 2014-2019. Several themes arose through analysis about features contributing to successful TRPs, including mentor development, resident development, and university programs embracing a transformative third space for teacher preparation. Each of the themes that emerged had an undertone of reflective refinement as teacher preparation programs innovate and develop their residency programs. The literature synthesis confirmed that teacher residencies have the potential to transform teacher preparation and improve upon university-school partnerships to bolster theory-to-practice connections. Teacher residency programs had specific features that appeared to contribute to these positive outcomes. Study #3: A Comparison Study between Residency and Traditional Teacher Preparation Models for Candidate Self-efficacy for and Ability to Teach Literacy, is a comparative study that explored self-efficacy and ability for literacy instruction between Traditional and Residency Models of teacher preparation. Quantitative data were collected using a pre-/post-survey design using the Teachers' Sense of Efficacy for Literacy Scale (TSELS). Mentor teachers completed a modified TSELS on candidates' abilities. Data were analyzed using paired sample t-tests, independent sample t-tests, and a trend analysis. Results revealed that candidates in the Residency Model increased more in self-efficacy for literacy instruction than in the Traditional Model. Mentor teachers rated candidates in the Residency Model as more able to teach literacy than the Traditional Model. There was alignment amongst the mentor rating and the resident perception of ability. In the Traditional Model, the mentor and student teacher were not nearly as aligned in their perspectives of student teachers' ability to teach literacy. Teacher preparation programs should consider the potential Residency Models have to prepare pre-service teachers for the use of evidence-based practices for teaching literacy.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Studies on the Survival of Ovarian Cancer Cells Following Treatment with Beta-Adrenergic Receptor Agonists and Antagonists
No full textM.S.Ovarian cancer is the second most common and the most lethal gynecologic malignancy, with a five-year survival rate of only 30%. Since ovarian tumors are difficult to detect until later stages, and have high rates of recurrence, the incidence and mortality rates have not seen any significant improvement in the past 20 years. Understanding the need for improved understanding of the mechanisms of relapse and resistance for the effective management of ovarian cancer, our goal was to examine the effects of signaling through the beta-adrenergic signaling pathway on the survival of ovarian cancer cell lines. Chronic signaling through the β2-adrenergic receptor specifically has been repeatedly demonstrated to have a direct impact on the progression and treatment of several different kinds of cancer. Using several in vitro models, we examined the effects of β-adrenergic signaling and antagonism on different ovarian cancer cell lines. Our results demonstrated a direct correlation between β-adrenergic signaling and chemotherapy resistance, as well as a correlation between β-adrenergic antagonism and cell death. These findings further support the therapeutic potential of targeting the β2-adrenergic receptor for the management of ovarian cancers.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Integer Programming Methods for Boolean Interdiction Games
No full textPh.D.Interdiction games are commonly used to model scenarios where two actors with conflicting objectives both aim to operate optimally. We define an abstract game called the Boolean interdiction that captures the essence of an important subclass of these interdiction games. Then, we use an application, the resiliency analysis of information distribution policies, to demonstrate the benefits of integrating interdiction techniques in other research areas. To study the Boolean interdiction game, we start with an interesting graph interdiction game, the minimum spanning tree interdiction, in which we developed several new tools: a set-covering formulation that interdicts all the critical spanning trees, a class of facets that enhances the efficiency of the searching procedure, and a family of special graph structures that results in a new solution method based on supervalid inequities. With the aid of these new tools, we study the Boolean interdiction game in full generality. First, we discover that under mild assumptions, all the single/double ground sets based Boolean interdiction can be modeled by a neat set-covering formulation. Second, we develop a large class of valid inequities, which unifies many previously identified structures in literature, to strengthen the set-covering formulation and all its instance problems. Last, we developed the theory of conditional critical structures, a new method based on the idea of partitioning the solution space into an easy part and a difficult part, then use the former to produce constraints for the latter. We identify the realizations of these structures in various instance problems and develop a general implementation framework. As a result, many current methods for solving interdiction problems can benefit from these developments. Moreover, the idea behind the conditional critical structures can be extended to other optimization problems.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Collaborative Action Research: Exploring Adult English Language Learners' Motivation to Read
No full textPh.D.Participants in adult education programs come from diverse linguistic and educational backgrounds, often with wide-ranging learning needs and personal and professional goals. Many rely on adult education programs for basic English and literacy skills; others need the programs to assist them in preparing for employment, high school equivalency, and to support their transition into postsecondary programs. This study used collaborative action research to examine how and in what ways computer-assisted reading programs facilitate reading motivation and comprehension among adults and English Language Learners in continuing education degree programs.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*
Constant-Roll Inflation, Phantom Dark Energy, & Bell Violation in the CMB
No full textPh.D.One of the most promising theories of the early universe is that of inflation [1–7]. Inflation predicts a period of accelerated expansion in the early universe, which provides simultaneous solutions for the flatness and homogeneity of the current universe. Furthermore, inflation predicts that scalar curvature perturbations from quantum fluctuations of the scalar field generating inflation result in areas of over- and under-density in the universe, leading to structure formation [8–16]. One family of inflationary models is that of single scalar fields. In single-field inflation, the field responsible for inflation, or inflaton, is taken to be displaced from a potential minimum. The field evolution is responsible for the accelerated expansion in the early universe which ends when the field value gets close to the minimum. The majority of this thesis focuses on work revolving around inflationary model building and quantum signatures of inflation on the Cosmic Microwave background. The structure is as follows. In Chapter 1 we will review general relativity and Einstein's field equations. Chapter 2 will cover the basics of inflation. Chapter 3 is devoted to the first collaboration I worked on, involving arbitrary gauge Phantom Dark Energy. One of my major projects, Constant-Roll Inflation, is covered in Chapter 4. The final work of my PhD on signatures of Bell's inequality in the CMB is covered in Chapter 5. Finally, we conclude in Chapter 6.**To request an accessible version of the file(s) associated with this item, contact [email protected]. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.*