bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue crack strengthening using pre-stressed composite patch
Authors:   , El-Emam Hesham M.
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The fatigue life of steel bridges can be extended by externally bonding carbon fiber reinforced polymer (CFRP) patches to the damaged elements arrest the crack propagation. Bonding a composite patch to a cracked steel section is an efficient technique to reinforce cracked members or to delay fatigue crack growth in the structural elements. In this thesis, the influence of the patch pretension level, patch stiffness ratio, and patch fiber orientation on the stress intensity factor levels, crack tip opening displacement and the plastic zone are investigated. A three-dimensional finite element model of the double sided CFRP patch-strengthened specimen is used to study the fracture behavior of an inclined edge crack under different combinations of loading modes I and II. It is found that the introduction of a compressive stress by pre-tensioning of the CFRP patch prior to bonding produced a significant reduction of up to 70% in SIFs for different crack lengths, which led to increasing the remaining fatigue life of the steel member. Also, it produces a significant reduction in the crack tip opening displacement and plastic zone. The increase in the CFRP patch-to-steel axial stiffness ratio, reduced the SIFs by up to 30%. The optimum benefit of using the CFRP patch to reduce mode I SIF was accomplished when the patch axial stiffness was about 50% or below the steel plate stiffness. Moreover, the increase in the patch stiffness ratio reduces the amount of plastic zone and opening displacement at the crack tip. Furthermore, orienting the fibers perpendicular to the crack direction is not necessarily the most effective in arresting the crack propagation. The effectiveness of the fiber orientation in the composite patch depends mainly on both the loading direction and the crack inclination angle. Concerns over means to improve fatigue behavior of cracked steel beams exist. This work presents the details of strengthening schemes that was carried out using prestressed ultra-high modulus carbon fiber reinforced polymer (UHM-CFRP) plates. Furthermore, an experimental investigation included the prestressing procedure. Steel W-sections were strengthened using different configurations with UHM- CFRP plates. The repaired specimens and control specimens were tested in cyclic four-point bending until fatigue failure. The study also considered the effects of CFRP end clamping force. A set of fatigue tests were conducted and results indicated that prestressed UHM-CFRP technique could increase fatigue crack propagation life 16 times longer than that of unrepaired one. The results also indicated that UHM- CFRP is effective at increasing fatigue life.
Monotonic and fatigue assessment of steel-concrete composite beams strengthened with externally post-tensioned tendons
Authors:   , Elzohairy Ayman
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The steel-concrete composite beam represents a structural system widely employed in both buildings and girder bridges. The coupling between steel beams and concrete flanges assures both economic and structural benefits because of quick construction of steel structures and large increase in stiffness due to the presence of concrete. Strengthening with external post-tensioning (PT) force is particularly effective and economical for long-span steel-concrete composite beams and has been employed with great success to increase the bending and shear resistance and correct excessive deflections. Applying external PT force to the steel-concrete composite beam is considered an active strengthening technique that can create permanent internal straining action in the beam which is opposite to the existing straining action due to the applied service loads. The most benefits of using this system of strengthening are an elastic performance to higher loads, higher ultimate capacity, and reduction in deformation under the applied loads. Under service loads, bridge superstructures are subjected to cyclic loads which may cause a premature failure due to fatigue. Therefore, fatigue testing is critical to evaluate existing design methods of steel-concrete composite beams. ... This research presents static and fatigue tests on four steel-concrete composite specimens to evaluate the effect of externally post-tensioned tendons on the ultimate strength and fatigue behavior of composite beams. Fatigue tests are conducted to a million cycles under a four-point bending test. In addition, final static tests are performed on fatigued specimens to evaluate the residual strength of the strengthened specimen. A numerical model is described to predict the fatigue response of the composite beam by considering the fatigue damage in the concrete flange. The accuracy of the developed numerical model is validated using the existing test data. The static test results indicate that the external post-tensioning force improves the flexural behavior of the strengthened specimen by increasing the beam capacity and reducing the tensile stress in the bottom flange of the steel beam. The fatigue results demonstrate that the external post-tensioning significantly decreases the strains in the shear connectors, concrete flange, and steel beam. The tendons demonstrated an excellent fatigue performance, with no indication of distress at the anchors.
Investigating the role of arginine 21 in the structure and function of human [alpha]a-crystallin
Authors:   , Phadte Ashutosh Shripad
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Cataractogenesis in the eye lens occurs as a result of protein aggregation. Of the multiple mutations in [alpha]A-crystallins associated with the development of congenital hereditary cataract, three identified mutations target R21 within the N- terminal domain of the protein. On structural and functional characterization of a recently identified mutant of [alpha]A-crystallin, [alpha]A-R21Q, we revealed the contribution of R21 in dictating the interaction of [alpha]A-crystallin with other proteins. [alpha]A-R21Q showed and enhanced chaperone-like function, and increased binding to lens fiber cell membranes. Transduction of mutant proteins in ARPE-19 cells prevented their apoptosis in the presence of oxidative stress, suggesting a role for R21 in modulating the anti-apoptotic function of [alpha]A-crystallin. In addition, the R21Q point mutation rescued the chaperone-like activity of [alpha]A-G98R crystallin as well as palliated [alpha]A-G98R mediated cytotoxicity otherwise observed in transduction experiments. Although another mutation, R157Q rescued the chaperone-like activity of [alpha]A-G98R, the double mutant exhibited a loss of its cytoprotective function. The results therefore implicate an important role of R21 in regulating the functional aspect of [alpha]A-crystallin. [alpha]A-crystallin derived peptides have been shown to prevent non-specific aggregation of unfolding proteins in vitro. We show that the [alpha]A-crystallin derived mini-chaperone (mini-[alpha]A) mediated stabilization of self-aggregating [alpha]A-G98R crystallin and bovine [subscript]-crystallin occurs via compensation of lost surface charge. The observation therefore suggests a plausible mechanism of action of [alpha]A-crystallin derived peptides of therapeutic interest.
Child death, grief, and the community in high and late Medieval England
Authors:   , Griego Danielle Nicole
Published: April 2021

"William of Canterbury, one of the authors of the Thomas Becket miracle collection, reports in a twelfth-century miracle that an eight-year-old boy named Phillip was looking at rocks by a lake located in the county of Cheshire, when he slipped and was overtaken by the water (aquis obrutus est). When he did not return home, his father, Hugh Scot, searched for him everywhere in the village and found his body submerged in the lake. Hugh was sighing and groaning (suspiriis et gemitu) after extracting him from the water, and when Phillip's mother heard about his death, she indulged in tears and wailing (lacrymis indulget et plactui).1 Rather than preparing the boy's corpse for a funeral, his parents attempted to revive him by suspending him by his feet in order to drain the liquid from his body, and when that did not work, by giving him holy water associated with Thomas Becket (aqua sancti Thomoe). According to William of Canterbury, because of the devotion of the parents (devotio parentum) and divine intervention, Phillip began to show signs of life, making his father leap forth (exsiliente) from his seat with excitement." -- Introduction
Detecting subtle variation in two cryptic primate families (tarsiidae and lorisidae) through morphology and genetics
Authors:   , Munds Rachel Anne
Published: April 2021

Cryptic species look morphologically similar but in fact are several different species lumped together. This is problematic as it hinders conservation efforts and makes it challenging to infer the evolutionary history of an organism. This dissertation research aims to improve our understanding of the evolution and variation of cryptic, nocturnal primates. Over 60% of primates are threatened with extinction, and many nocturnal species are poorly understood. Research aimed at elucidating species will help conserve them. To do so, I examined the multivariate craniodental allometry of the three genera of tarsiers. Tarsiers are small-bodied, nocturnal primates that have evolved to extreme-carnivorous niche. In order to see better at night their eyes have increased dramatically in size. Such evolution has led to minimal cranial variation among the three groups, despite millions of years of separation. Yet, two distinct groups were found through allometric analyses. Genetics is another tool that can discern the evolution and variation of cryptic species. The slow moving lorises of Asia and Africa appear morphologically similar, making it a challenge to determine their evolutionary history or variation. By using a multi-gene approach, I was able to determine the family is monophyletic with four distinct genera. Furthermore, analyses of a candidate gene that impacts coat color variation, found that the darker colored African genus has more mutations along its branch that result in amino acid changes than the vibrantly colored lorises in Asia. Such a result suggests that a transition to or a maintenance of a darker phenotype is conserved or that other genes besides this one candidate gene influence coat variation. Overall, I was able to find that through a variety of methods, it is possible to detect variation and the evolutionary history of cryptic species.
Essays on climate econometrics
Authors:   , Nam Kyungsik
Published: April 2021

This paper proposes a nonlinear cointegrating regression model based on the well-known energy balance climate model. Specifcally, I investigate the nonlinear cointegrating regression of mean of temperature anomaly distributions on total radiative forcing using estimated spatial distributions of temperature anomalies for Globe/Northern Hemisphere/Southern Hemisphere. Further, I provide two types of nonlinear response functions that map from the total radiative forcing level to mean temperature anomalies. Cointegration and specifcation tests are also provided that support the existence of nonlinear effects of total radiative forcing.
Structural geology, tectonic geomorphology, and neotectonics of the central Afar Rift, Ethiopia and Djibouti
Authors:   , Polun Sean Gifford
Published: April 2021

The central Afar depression offers an opportunity for quantitative analysis of the final stages of continental breakup at a divergent triple junction. Here, Quaternary faulting dissects Plio-Pleistocene flood basalts, providing a regionally pervasive datum to quantify the regional finite strain and fault scaling laws. To this end, I mapped and measured more than 8500 normal faults using remote sensing products. Fault length generally follows a power law distribution, but exponential distributions are found in areas of magmatic extension. Fault throw and fault length scale following a power law relationship where T = 0.031L[subscript 0.96], similar to previous studies in Afar and elsewhere in the world. Combining the power law distribution with this throw scaling enables a comprehensive assessment of Quaternary finite strain throughout the region. The presence of moderate to high strain in the amagmatic portions of the central Afar rift suggests that those areas accommodate a significant proportion of plate motion. This may provide a future path for propagation between the Gulf of Aden Rift and the Red Sea Rift . ... In order to examine the kinematic evolution of the central Afar, I conducted a morphotectonic analysis on fault scarps in unlithified alluvial material to determine uplift rates on major faults across the region. I have analyzed fault scarps in Hanle, Dobe, Guma, and Immino grabens, and document a northwest decreasing trend in uplift rates. Along a transect parallel to the mean extension direction, the cumulative extension from these faults is 1.09 mm/yr. The decreasing trend in slip rates is incompatible with the â€œBookshelf Faultingâ€ model commonly applied to explain deformation in the central Afar. Instead, the more likely model involves distributed extension across the region, possibly resulting from the rotation of the Danakil block away from stable Nubia.
Transcending the technical : an examination of spirituality in choral music making for selected public
Authors:   , Cox Jordan Lee
Published: April 2021

The purpose of this phenomenology was to contribute to the examination of the role of spirituality in choral music making for public school choral conductors in the United States. Since the year 2000, the topic of spirituality has been a growing area of interest for researchers, particularly in the fields of nursing, social sciences, and education. To better understand the phenomenon of spirituality within music education, eight public high school choir conductors who were members of the American Choral Directors Association, had taught for at least five years, and had experienced spirituality in choral rehearsals or performances were interviewed face-to-face or via online video-conferencing software, using a self-developed interview guide with open ended questions. Participants included four males and four females from Missouri, Illinois, Iowa, and Florida. The findings of this study supported previous literature on spirituality by contrasting spirituality from religion, and described spirituality as students engaging in musical experiences that transcended the fundamentals of music, involving the whole person: body, mind, and spirit. Participants shared that a certain level of technicality must be achieved before a spiritual experience would occur, but a flawless performance was not required. The participants expressed the need for vulnerability and authenticity in the classroom modelled by the teacher, but the strongest theme throughout the data was the value placed on various connections. These teachers discussed connection to the music, particularly the text, connection between the teacher and the students, connection among the students themselves, connection to the divine, and connection to the audience. The teachers suggested those interested in engaging their students in spiritual experiences could cultivate these connections through large/small group discussion, studying the cultural and historical background of the music, use of metaphors and imagination, self-reflection, journaling, sharing personal stories, engaging in ice-breakers and team building activities, mindfulness exercises, in personal interactions, and through the use of inspirational quotes. When asked to define spirituality in the context of choral music, each participant admitted that it was difficult to define, but expressed it as something bigger than themselves, tied to a greater purpose, calling, and/or worldview, and often expressed hope that students would gain this greater perspective on life.
Essays on applied macroeconomics and monetary policy
Authors:   , Dhital Saroj
Published: April 2021

The dissertation presents three essays in applied macroeconomics and monetary theory. First essay explores the existence of global financial cycles and examines the relationship between financial and macroeconomic sectors at a global scale. I find that there exist significant cycles in financial variables and the contribution of the financial shocks on global macroeconomic sector is significant and varying over time. Second essay examines the role of decentralization on regional convergence using night-time satellite lights data as proxy for regional economic activities. I find that the decentralization hinders regional convergence in the sample of developing countries. Third essay analyzes active and passive fiscal and monetary policy regime in the presence of long and short-maturity government debt. I utilize the advances made in money search model to analyze the policy regimes. I find that while there are some similarities between the regime, there are also significant differences. I also find that the results using money-search model can be different than using a reduced form models.
Absolute continuity of parabolic measure and the initial-dirichlet problem
Authors:   , Genschaw Alyssa
Published: April 2021

This thesis is devoted to the study of parabolic measure corresponding to a divergence form parabolic operator. We first extend to the parabolic setting a number of basic results that are well known in the elliptic case. Then following a result of Bennewitz-Lewis for non-doubling harmonic measure, we prove a criterion for non-doubling caloric measure to satisfy a weak reverse Holder inequality on an open set [omega] R(n+1), assuming as a background hypothesis only that the essential boundary of [omega] satisfies an appropriate parabolic version of Ahlfors-David regularity (which entails some backwards in time thickness). We then show that the weak reverse Holder estimate is equivalent to solvability of the initial Dirichlet problem with "lateral" data in [Lp], for some p less than [infinity]. Finally, we prove that for the heat equation, BMO-solvability implies scale invariant quantitative absolute continuity of caloric measure with respect to surface measure, in an open set [omega] with time-backwards ADR boundary. Moreover, the same results apply to the parabolic measure associated to a uniformly parabolic divergence form operator (L), with estimates depending only on dimension, the ADR constants, and parabolicity, provided that the continuous Dirichlet problem is solvable for (L) in [omega]. By a result of Fabes, Garofalo and Lanconelli [FGL], this includes the case of [C1]-Dini coefficients.
Virtus et disciplina : an interdisciplinary study of the roman martial values of courage and discipline
Authors:   , James Justin Ryan
Published: April 2021

This thesis discusses Roman martial values, principally virtus and disciplina, and their literary characterization. This is an interdisciplinary study that employs data and methodologies from anthropology, evolutionary biology, moral philosophy, military history, and analytical psychology to supplement scholarship from classical studies. My aim is to analyze and interpret, as deeply and profoundly as possible, the values that the Romans regarded as essential to their military success. I argue that Greek and Roman authors depict nuanced but relatively consistent representations of Roman martial values, which both derive from actual Roman military practice and project an important component of Roman cultural identity. Virtus was a virtue that primarily denoted martial courage, an ethical quality, while disciplina functioned as a means to virtus, but it was not necessarily a virtue itself. The premises of my argument are as follows: 1) military doctrine reflects culture, which manifests in the projection of Roman values through military narratives; 2) there is significant agreement among classical authors discussing Roman warfare in the abstract; 3) historiography distorts to some extent but is not deliberately mendacious, which derives from the relatively meritocratic hierarchies cultivated by the Roman army; 4) an appreciation of archetypal imagery has utility in interpreting Roman values, given that the primary evidence for these qualities derive from stories imbued with moral instruction.
The imperial cult and the individual : the negotiation of Augustus' private worship during his lifetime at Rome
Authors:   , McGraw Claire
Published: April 2021

This dissertation argues for a reevaluation of the imperial cult in Rome. It demonstrates that worship of the living Augustus began in private acts which progressed into public rituals after his senate-decreed divinity in 14 CE. Scenes of private worship, preserved in architecture, poetry, and the city's topography, as well as private images of the emperor anticipate Augustus' public cult as a divus (deified emperor). The chapters show how the climate in Rome allowed for the private articulation of Augustus' living cult, and then address specific aspects of his worship: sacrifice, cult places, and cultic statues. This argument expands our understanding of Augustus' divinity in Rome to include worship of the vivus (living emperor), and demonstrates how this worship transitioned into public cult. No less importantly, it challenges lingering modern assumptions about the boundaries between divinity and humanity as these played out around the figure of the emperor in early imperial Rome.
Feeding the beast : macroeconomic drivers of leadership responses to foreign policy action and the gendered consequences for human trafficking
Authors:   , Perry Katherine Jeanette Elizabeth
Published: April 2021

How do the gendered macroeconomic and macropolitical structures of the international system exacerbate the rise in human trafficking? In this dissertation project, I use a mixed method approach to examine the relationship between domestic leadership responses to foreign policy actions and how those responses lead to rises in human trafficking in the target state. I begin with cross-national, quantitative models to illustrate that following two different types of foreign policy action, namely, economic sanctions and military force, domestic leaders are driven by the macropolitical interstate system to choose between hoarding finite resources among elites within the target state or redistributing those resources among the populace. I argue that when leaders choose to hoard resources, the populace suffers from lack of social program support and women are particularly vulnerable under such conditions. Leadership focus on self-preservation reduces government support for public programs such as anti-trafficking policy. The populace is then much more likely to choose illicit economic activities such as human trafficking to survive and without support for anti-trafficking in the target state, human trafficking flourishes. The macroeconomic structure of global capitalism relies on cheap labor and cheap goods which specifically reduces the options for women under times of financial duress, and women will suffer significantly as government spending on safety net programs is reduced. I support the quantitative results using a qualitative case study on Indonesia, which I develop using historical documents and resources. Ultimately, this project highlights the importance of developing anti-trafficking policies that do more than punish individual perpetrators but instead, acknowledge the negative impacts of the macroeconomic and macropolitical structures in international relations and how those structures significantly harm women throughout the world.
Applied problems in frame theory
Authors:   , Botelho-Andrade Sara
Published: April 2021

This thesis is a study of two applied problems in frame theory: phase retrieval and quantum detection. These problems are inspired by engineering applications in signal processing and information theory. ... The goal of the injectivity problem is to classify frames which are injective with respect to self-adjoint Hilbert-Schmidt operators. By associating vectors x [is an element of]H[superscript n] with vectors [median]x in a larger space, we are able to use standard linear algebra and functional analysis techniques to provide characterizations for the injectivity problem in complex and real Hilbert spaces, as well as construct solutions. Given an injective frame, the goal of the state estimation problem is to construct a self-adjoint trace one operator T such that the vector with coordinates less than Tx[subscript k], x[subscript k]> is equal to a predetermined measurement vector. We give equivalent conditions for solvability of the state estimation problem and provide best approximate solutions when no exact solution is possible. We also show results about density of both problems.
Are social media bad for your employees? : effects of at-work break activities on recovery experiences, job satisfaction, and life satisfaction
Authors:   , Cheng Yi-Sung
Published: April 2021

Despite the alleged importance of work breaks, little is known about antecedents and consequences of social media break activities besides non-social media break activities. Since individuals use social media to contact friends and families, find information, and be entertained, this study theorized that engaging in social media break activities while at work can help employees to experience psychological detachment and relaxation during work hours. The purpose of this study was to explore this growingly popular topic of social media use at work by focusing on job demands that may explain why employees perceive social media are vital for them at work. Further, this study seeks to understand when and how employees use social media at work to experience recovery, which, in turn, increases their job satisfaction and life satisfaction. Questionnaires were collected from current hospitality non-managerial and managerial employees in the United States. Structural equation modeling was employed to analyze data. Results of the study confirm that at-work break activities including social and non-social media break activities can be a channel for employees to experience recovery and deal with job demands. Moreover, the results suggest that when employees reported their perceptions of recovery experiences, positive perceptions had a positive impact on job satisfaction and life satisfaction. The findings also indicate that employees who are happy at work have a high life satisfaction. The results fill an empirical gap in the theoretical literature on at-work break activities and recovery. This study offers further insight and empirical evidence about the positive outcomes of both social and non-social media break activities to researchers, practitioners, and human resource professionals.
Investigating pore-forming peptides using the atomic force microscope
Authors:   , Pittman Anna Elizabeth
Published: April 2021

In my projects, I used the Atomic Force Microscope (AFM) to image the effects of pore-forming peptides and I used the Focused Ion Beam (FIB) to modify AFM cantilevers to increase the precision of force spectroscopy measurements. ... Another way to investigate peptide-lipid interactions is to perform force spectroscopy experiments using the AFM. In order to lower drift and increase force precision, I used a FIB to modify commercially available AFM cantilevers. By reducing the cross sectional area of the cantilever, the hydrodynamic drag was reduced, thus increasing the force precision. Removing most of the gold coating on the cantilever increased the temporal stability. These modified cantilevers have already been put to use in the lab to measure peptide-lipid interactions.
A projection from the hypothalamic paraventricular nucleus to the nucleus tractus solitarii is critical for cardiorespiratory responses to hypoxia
Authors:   , Ruyle Brian
Published: April 2021

The arterial chemoreflex is an essential protective mechanism for adaptive responses to hypoxia. Stimulation of peripheral chemoreceptors initiates a reflex response that generates compensatory physiological responses, including increased ventilation, arterial pressure and sympathetic nerve activity. However, chemoreflex dysfunction, including over-excitation of chemoreflex pathways, leads to respiratory instability and increased sympathetic nerve activity (SNA) in disease states including heart failure, hypertension and obstructive sleep apnea (170, 199, 232). Determining the mechanisms involved in the central chemoreflex neurocircuitry and its plasticity in health and disease may lead to the development of targeted therapies in cardiorespiratory disease. This dissertation seeks to provide new insight into the neural circuits that drive chemoreflex function. Compensatory responses to chemoreflex stimulation are generated through coordinated interactions between nuclei in the brainstem, forebrain and spinal cord. However, the underlying neurocircuitry, including relevant connections between these nuclei, and the signaling mechanisms that take place within each region are not completely understood. The nucleus tractus solitarii (nTS) and the paraventricular nucleus (PVN) are two central nuclei known to drive chemoreflex function and are implicated in altered cardiorespiratory responses resulting from chemoreflex dysfunction. These two regions form reciprocal connections but the extent to which these connections influence cardiorespiratory regulation and specifically chemoreflex function is unclear. The overarching goal of this dissertation is to examine whether a population of PVN neurons that project to the nTS is involved in shaping cardiorespiratory responses to chemorefle activation by hypoxia. The experiments performed in the three studies (Chapters 2-4) test the overall hypothesis that a descending PVN-nTS projection is an essential component of chemoreflex neurocircuitry; chemoreflex-evoked activation of this pathway is critical for compensatory cardiorespiratory responses to hypoxia.
Sharp things, or the silver lines are not scars
Authors:   , Milbrodt Teresa
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This novel is the story of Tianne, a twenty-eight-year-old stained glass artist. She works two part-time jobs as a clerk at a stained glass supply store, and as an adjunct instructor at a community college. Her boyfriend Jeremiah is an academic adviser at the same college, but wants a career performing in comedy clubs. He uses a wheelchair due to spina bifida, and is cheerfully blunt that he could die from an undetected kidney infection. Tianne wrangles her own invisible disability, since endometriosis causes her to have awful cramps during her period that can keep her home from work. Tianne loves her jobs but worries about bills after her car breaks down. She envies Jeremiah's financial stability until he's fired for speaking his mind too many times to administration. Tianne fears for his health insurance coverage, while Jeremiah debates careers as a high school guidance counselor or touring comedy clubs. Throughout the book Tianne tries to chart a path though the instabilities of her body, Jeremiah's body, their career paths, and their romantic relationship, knowing that nothing is permanent. Hers is a story not of looking for stability, but coming to terms with instability, and finding spaces of adaptation to constant change.
3D printing of active polymeric materials
Authors:   , Su Jheng-Wun
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Learning from nature livings, especially those that can respond to the stimuli and change the shape, is attracting increasing interests in a wide variety of research fields. There is a significant need of developing synthetic materials that can mimic these living systems to show dynamic and adaptive shape-changing functions. Although various fabrication methods including molding, micro-fabrication and photolithography have been developed to fabricate the dynamic materials, they all have shown some limits. At present, 3D printing is a promising technique, which provides a cost effective, accurate and customized method to form 3D structures. The recently new emerging technique, 4D printing, which employs the 3D printing to print the active materials for dynamic 3D structures, shows a great potential for various applications such as tissue engineering, flexible electronics, and soft robotics. Despite much recent progress, this technology and its application in 3D dynamic structure fabrication is still in its infancy. My Ph.D. dissertation focuses on 4D printing of programmable polymeric materials that exhibits complex, reversible, shape transformations as well as enriching the printable material library by exploring various active materials for 4D printing technology. Chapter 1 introduces the current development of active materials and methodologies. Much attention is paid to the recent progress and its merits and demerits. Chapter 2 presents a simple and inexpensive 4D printing of waterborne polyurethane paint (PU) composites that are fabricated by mixing PU with micro-size preswollen carboxymethyl cellulose (CMC) and silicon oxide nanoparticle (NPs), respectively. Chapter 3 presents the 4D printing of a commercial polymer, SU-8, which has yet been reported in this field. The self-morphing behaviors of the printed SU-8 structures are induced by spatial control of swelling medium inside the SU-8 matrix. In Chapter 4, machine learning algorithms are applied to evaluate the shape-morphing behaviors of 4D printed objects. After the model optimization by tuning the hyperparameters the obtained machine learning models enable to accurately predict the final curvatures and curving angles of the 4D printed SU-8 structures from given input geometrical information. This initial success show that these data-driven surrogate models can well circumvent the challenge of human centered trial-and-error process in optimizing the printed structures, thereby pushing the research in 4D printing to a new height.
The relationship between professional learning community implementation and teacher decision-making
Authors:   , Bowles Mark
Published: April 2021

Educational reform has been a topic of intense interest since the 1950's (Brost, 2000; Lambert, 2003; Servage 2009; Watson, 2014). Researchers have routinely proposed that schools must evolve to be much more adaptable and much more responsive to students' needs (Brost, 2000; Servage, 2009). A great deal of educational research exists that indicates that, in order to accomplish educational reform, teachers must be more involved in decision-making processes (Brost, 2000; Conley, 1991; DuFour and Eaker, 1998; Odden and Wohlstetter, 1995; Liontos, 1993; Smylie, Lazarus and Brownlee-Conyers, 1996; York-Barr and Duke, 2004); and empowering teachers to reflect, collaborate, and act collectively as a means to enhance student achievement figures prominently in many current public school reform initiatives (Duffy, Mattingly, and Randolph, 2006; DuFour and Eaker, 1998; Gates and Watkins, 2010). According to Howey (1988), teacher leadership is both natural and necessary in today's climate of increasing demands for excellence being placed on schools. His assertion that reform can only be effective if addressed by those who reside where the problems are is a common theme in educational research (Brost, 2000; Clark and Clark, 2002; Liontos, 1993; Odden and Wohlstetter, 1995; Smylie et al., 1996; York-Barr and Duke, 2004).
A practice-based intervention to prepare preservice teachers for inclusion using universal design for learning
Authors:   , Decker Mary Elizabeth
Published: April 2021

General education pre-service teachers are expected to teach diverse learners, including those with disabilities, in the general education settings. Yet many are not adequately prepared to teach all students. Universal Design for Learning (UDL) is a framework to increase inclusive practices, however, it is unknown how to best teach this to pre-service teachers. The purpose of this study is to examine the impact of using a practice-based approach to teach UDL as compared to a lecture-based approach to teach UDL to better prepare general education pre-service teachers. Constructs of interest include pre-service teachers' fundamental knowledge including UDL, self-efficacy and UDL application. A mixed methods triangulation design was employed. While pre-service teachers from both groups had significant gains in their foundational knowledge, reported self-efficacy, reported UDL knowledge and ability to apply UDL ideas, participants in the practice-based group did have some advantages, specifically in the area of UDL application.
A phenomenological study of lived experiences of learning communties in online courses among undergraduate pre-service teachers
Authors:   , Bradley Chelsea Kay
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This phenomenological study examined lived experiences of learning communities among pre-service teachers within online undergraduate college courses from a new literacies perspective. Online learning continues to grow rapidly in higher education. As institutions of higher education develop online courses and students participate in those courses, various issues arise: retention rates, feelings of isolation, and a decrease in feelings of success. Learning communities can combat these issues, but they must first be effectively implemented. This study addressed participants' common lived experiences of learning communities. To collect data, the researcher conducted three in-depth interviews with each of the 12 study participants. Based on these interviews, online undergraduate pre-service teachers' lived experiences of learning communities in their online college courses were relationship-based, generated by communication, and technologically bound.
Kinetics, mass transfer, and mass re-equilibrium for arsenate adsorption on iron oxide-based carbons
Authors:   , Wang Zhengyang
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Removal of arsenic (As) from drinking water sources is much needed worldwide, and small water treatment systems, such as point-of-use (POU) treatment, could be an effective solution for residential applications. Adopting existing removal technologies that are successful in large-scale treatment to small-scale units, however, is rather ineffective due to the short hydraulic residence time in small water treatment systems. â€¦ The Freundlich isotherm can fit experimental data well: a crossover point for the two fitted Freundlich isotherms was observed and nano-FeAC had higher adsorption plateau. Furthermore, we demonstrated that due to the MRE process, a pseudo-equilibrium of FeMC was altered to another steady state by an in situ extraction with nano-FeAC in both batch and column systems. The overall inter-medium mass transfer resulted in both improved adsorption densities obtained by batch tests and a large bed volume prior to the 10 [mu]g As/L breakthrough at a short empty bed contact time (0.85 min).
Green solvent-enabled biomass conversion for renewable chemicals and lignin upgrading
Authors:   , Chen Zhu
Published: April 2021

Lignocellulosic biomass, which is mainly composed of cellulose, hemicellulose, and lignin, is a promising feedstock for producing renewable chemicals and fuels. To make lignocellulosic biomass-based refinery (biorefinery) competitive with petroleum refinery, maximizing the utilization of the three major components is critical. This requires the efficient fractionation of lignocellulose into different streams amenable to further upgrading. To this end, this work investigated the use of quaternary ammonium salt-based green solvents for lignocellulose fractionation and upgrading into renewable chemicals. First, a platform solvent system based on choline chloride and ethylene glycol was developed for switchgrass fractionation. Tailor-made lignin can be produced by using this platform solvent system, while the delignification and cellulose digestibility were not compromised. Highly concentrated sugar hydrolysate from pulp (cellulose) streams can be obtained via high solid loading enzymatic hydrolysis. The hemicellulose streams can be facilely upgraded into furfural via a novel biphasic system-acetone and aqueous choline chloride: ethylene glycol (ChCl:EG). Secondly, switchgrass can be fractionated effectively at high solid loading using either aqueous ChCl:EG or a series of ternary deep eutectic solvents. The cellulose stream can be converted into highly concentrated hydrolysate for high titer platform chemical production via fermentation. The hemicellulose and lignin streams can also be converted into other value-added products via other upgrading pathways. Thirdly, aqueous ChCl can also be a good solvent for switchgrass fractionation at mild conditions. The resultant lignin presented a very similar structure to native lignin, and thus, a great potential to be valorized into different products. The hemicellulose and cellulose streams can also be converted into valuable chemicals via biological and chemical routes. Lastly, a one-pot process capable of directly converting the untreated lignocellulosic biomass into furfural, digestible cellulose pulp and high purity lignin was developed. Furfural can be produced with high yield, while cellulose and lignin with appealing properties can be obtained via a one-pot process.
Transnationalism from below : an exploration of transnational engagement behavior of Nicaraguan immigrant entrepreneurs
Authors:   , Tappmeyer Andrea Marie
Published: April 2021

This study explores the concept of transnationalism through individual experiences of migrants from the community of Villa Sandino, Nicaragua that have become entrepreneurs as immigrants in the United States. Through semi-structured interviews, their unique entrepreneurial journeys and transnational engagement are examined using qualitative research methods. Both with-in and temporal cross case analyses were utilized to present a comprehensive investigation. Specifically, the determinants, motivations and strategies of these immigrant Latino entrepreneurs that participate in transnational engagement are observed. Also, the experiences of the immigrant entrepreneurs are explored to understand the local ecosystem and institutions that supports these individuals' entrepreneurial success in their receiving communities of San Francisco and Miami as well as investigate the concept of transnationalism from below.
Development of novel site-specific imaging probes for prostate cancer detection
Authors:   , Jiang Lingyan
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Molecular imaging is believed to play a pivotal role in decreasing cancer mortality and improving prognosis in the new era. It relies on molecular probes to image cellular or molecular abnormalities in living body. The primary objective of this research is to develop novel multimodal molecular imaging probes, via nanotechnology and peptide conjugation chemistry, for site-specific targeting and imaging of human prostate cancers. A novel nanoparticle based bimodal MRI/fluorescence molecular imaging probe was developed, characterized, and studied for its capacity to target gastrin releasing peptide receptor (GRPr) which is overexpressed in human prostate cancer. Synthesized USPIO(Cy7.5)-BBN nanoparticles have a small core size (5 nm), a high MRI relaxivity, and a superior binding affinity and specificity to the GRPr overexpressed on human prostate cancer in vitro and in vivo. Furthermore, SIO-AF750-BBN, a silica-coated iron oxide nanoparticle loaded with near infrared fluorescence (NIRF) dyes and bombesin, was developed as a tri-modal photoacoustic (PA), NIRF and MRI imaging probe. SIO-AF750- BBN displayed a high binding affinity and specificity to the GRPr expressed prostate cancer cells in vitro and in vivo. SIO-AF750-BBN demonstrated a significant photoacoustic contrast enhancement in tumor tissues, i.e. 3 and 5-fold as compared to the receptor-blocking control group and the peptide analog AF750-BBN without attachment to a nanoparticle, respectively, after intravenous tail vein injection in tumor bearing mice. In addition to bombesin agonist as the targeting moiety, bombesin antagonist is also explored. A series of bombesin antagonists with three different NIRF dyes and three pharmacokinetic modifiers were synthesized and characterized. Of those, three bombesin antagonist analogs, AF750-G-pip-Sta-BBN, AF750-GSG-Sta-BBN, and AF750-6Ahx-Sta-BBN, exhibited high NIRF imaging efficacy, high binding specificity and inffinity, and antagonism to human PC-3 prostate cancer cells both in vitro and in vivo. In conclusion, this Ph.D. work addresses the issues of discovery and development of novel site-specific and multi-modality molecular probes for cancer targeted imaging. USPIO(Cy7.5)-BBN displayed the capacity to generate imaging contrast enhancement for prostate tumors in living bodies on MRI/NIRF. The SIO-AF750-BBN demonstrated tumorspecific photoacoustic signal enhancement, as well as near-infrared fluorescent imaging enhancement after intravenous administration of this agent in human prostate cancer animal model. Finally, AF750 labeled bombesin antagonist analogs were developed and demonstrated to have a high binding affinity and selectivity to the GRPr and a desirable in vivo bio-distribution profile, indicating their high potentials to be translated to clinical use for imaging-guided surgery and therapy.
Design, fabrication, and testing of a bioprinted nerve graft
Authors:   , Owens Christopher M.
Published: April 2021

Injuries to nerves vary in their consequences, from weakened sensation and motor function to partial or complete paralysis. In the latter case, affecting about twenty thousand Americans yearly, the injury is debilitating and results in a significant decrease in quality of life. Currently there is no effective treatment for damage to the central nervous system, in particular the spinal cord. Compared to the injuries to the central nervous system, damage in the peripheral nerves, is more common, with about sixty thousand occurrences annually. The cost of associated surgical procedures and due to loss of function is in the billions. In this thesis we present work towards the construction and testing of a fully cellular, patented nerve graft, one amongst the first of its kind. For the fabrication of the graft we are the first to employ bioprinting (either implemented through a special purpose 3D bioprinter or manually), a novel tissue engineering method rapidly gaining acceptance and utility. We first review the status of bioprinting. We then detail the fabrication process. Next we report on the testing of the graft in an in vivo animal model through electrophysiology and histology. This is followed by the introduction of a novel in vitro model, aimed at providing a fast, inexpensive and reliable method to test engineered nerve grafts. We describe our work on the optimization of the in vitro assay and then the testing of the graft using the optimized assay. We conclude with a summary of our accomplishments and make suggestions for some exciting future applications of our approach.