bluuebunny/crossref_metadata_2025 huggingface dataset:
A comprehensive report on preparing and analyzing adsorptive materials suitable for hydrogen and methane storage
Authors:   , Rash Tyler Austin
Published: April 2021

Development of low-pressure, high-capacity adsorbent based storage technology for methane, natural gas, and hydrogen as fuel for advanced transportation is necessary in order to address the temperature, pressure, weight, and volume constraints present in conventional storage methods (CNG, LNG, and LH2). Subcritical nitrogen adsorption experiments show that our nanoporous carbon hosts extended narrow channels which generate a high surface area and strong van der Waals forces capable of increasing the density of natural gas and hydrogen into high-density fluids. Improvements in storage density over compressed natural gas without an adsorbent occur at ambient temperature and pressures ranging from 0- 260 bar. The storage capacity custom built 10.6 L hydrogen adsorption instrument with activated carbon adsorbents synthesized at MU is 32 g/kg at 296 K and 100 bar which is higher than what has been reported in literature for other materials. The temperature, pressure, and storage capacity of a 40 L flat-panel adsorbed natural gas tank filled with 20 kg of activated carbon is featured. Results from the 40 L instrument show that the monolithic adsorbents within allow for rapid charging and discharging and an ideal balance between methane gravimetric and volumetric storage capacity. A 300 kg/(m3 day) space time yield for the production of the monolithic adsorbents is demonstrated.
Investigation of the synthesis of water-soluble 1,3,5-trihydroxy-2,4,6- trimethylsulfonic acid benzene, its complexes with lanthanide cations and sulfonato-resorcin[4]arenes, and the study of gas storage in iodine doped p-tert-butylcalix[4]arenes
Authors:   , Ruaysap Makabodee
Published: April 2021

The design of new calixarene derivatives based on supramolecular principles -- the formation of molecules, ions, or complex ions with the weak non-covalent interactions to form a larger moiety with applicable properties compositioned by the starting material's attributes -- has attracted attention in many scientific fields. Herein, the new synthesis method of 1,3,5-trihydroxy-2,4,6-trimethylenesulfonic acid benzene, 1 was studied. As a result, the new synthetic method was less complicated and required fewer steps than that of the previous work. This compound also presents a novel tautomeric conformational change using NMR spectroscopy. Furthermore, the lanthanide (Sm, Eu, La, Ho, and Nd) complexes of 1 are isostructural and the packing of the complexes is a bilayer structure arrangement with ?-stacking between the benzene rings. In addition, the study investigated the formation of tetramethylsulfonatoresorcin[4]arenes, a diaza-18-crown-6, and LN(III) metal ions such as europium (Eu) holmium (Ho), and samarium (Sm) and their crystalline structures using single crystal X-ray crystallography. The results show the various ways that these molecules can assemble into different supramolecular frameworks. Different solvents result in drastically the different packing of these molecules resulting in the diverse range of packing motifs. Hydrogen gas-storage properties of modified p-tert-butylcalix[4]arenes with doping by iodine molecules (I2 doped TBC4) was studied. The iodine-doped p-tert-butylcalix[4]arenes are structurally studied by using the 1H-NMR, 13C-NMR in liquid and solid-state 13C-NMR, and single crystal X-ray crystallography. The decomposition temperature was studied by thermogravimetric analysis. Iodine doped p-tertbutylcalix[4]arenes show an evidence of hydrogen gas-sorption which is a good sign that the new material, Iodine-doped - p-tert-butylcalix[4]arenes can possibly be developed for hydrogen gas storage in the future. Notably, the weak non-covalent interactions that are often responsible for the formation of supramolecules are also responsible for reversible adsorption/desorption properties found in host-guest systems. Examples of guest species include gases, organic molecules, inorganic complexes, and metal ions. Therefore, this research is dedicated to exploring and designing new materials for sorption/desorption purposes, as they may be useful in storage of fuel gases, for carrying/releasing drugs to the target parts of the body, or used as biological mimics.
Harriet Beecher Stowe and the circulation of texts
Authors:   , Specter Gregory David
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This dissertation argues that even though Harriet Beecher Stowe participated in models of circulation throughout her career, they were shaped by drastic changes in the technology of print and transportation. Stowe witnessed changes in print culture that, in her view, detrimentally altered social relationships that print once fostered between people. This dissertation argues that Stowe saw a tightening relationship between publishers and other entities that overwhelmed readers with abundance. This profusion of print made it less personally valuable to readers and drastically altered print's ability to foster communal relationships. This dissertation examines Stowe's uneasiness and resistance to later models of print culture through her depiction of the role of letters, her use of prefaces, and through the recirculation of ideas in altered material forms echoing the scrapbook.
Being social in a 3D collaborative virtual learning environment : a case study of youth with autism spectrum disorder learning social competence in iSocial
Authors:   , Wang Xianhui
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Over the past decade 3D collaborative virtual learning has gained increasing attention from researchers and practitioners in educational technology. Learners experience of presence in collaborative activities and social interactions among learners are identified as key constructs for the social dimensions of 3D collaborative virtual learning. 3D Collaborative Virtual Learning Environments (CVLEs) are beginning to be used to support learning in a variety of disciplines, including social skills learning for individuals with Autism Spectrum Disorder (ASD). This case study explores 11 youth with ASD's experience of embodied social presence and reciprocal social interaction while learning social competence in a 3D CVLE-iSocial. The findings describe youth with ASD's 1) levels of embodied presence, embodied copresence, and embodied social presence; and 2) verbal and nonverbal reciprocal social interactions across the variety of Naturalistic Practice activities in iSocial. In addition, the results of this case study inform future design by indicating associations of design features of iSocial 3D CVLE with youth with ASD's experience of embodied social presence and characteristics of reciprocal social interaction.
Managing uncertainty during unemployment : a phenomenological exploration of social class differences
Authors:   , Wickert Jonathan Edward
Published: April 2021

This research address a relevant and important problem, unemployment. After 2008 unemployment steadily increased leaving many people out of work and causing concern for others. This study attempts to understand how people from different types of work experience unemployment. The data was gathered through interviews with 31 people who were experiencing unemployment. To assist in understanding their experiences, each participant provided pictures of anything they thought symbolized their unemployment experience. People commonly took pictures of their cars, empty wallets, and closed doors or hallways. Findings from this study suggest that participants anticipated being able to find a new job. However, participants described experiencing uncertainty after multiple failed attempts to find work. Additionally, social class positioning exposed text (white-collar) workers to valuable job search related resources; whereas body workers (laborers) struggled to manage the job search and meet their basic needs such as food and shelter. Lastly, both text and body workers described feeling stigmatized by their unemployment status and chose to withdraw from interactions with others to avoid feeling stigmatized. As a result of these findings, practitioners are encouraged to help laborers translate their physical work experiences into written text that is useful in the job search process. Practitioners can also help text and body workers develop strategies for managing the unemployment stigma that does not hinder their ability to find a new job.
Characterization of a novel regulator and predictors of sensitivity to trail-induced apoptosis in breast cancer cells
Authors:   , Dine Jennifer
Published: April 2021

Mesenchymal triple negative breast cancer (TNBC) cells are very sensitive to tumor necrosis factor-related apoptosis inducing ligand (TRAIL) for reasons that are poorly understood. The purpose of this study was to characterize a negative regulator of TRAIL sensitivity in TNBC cells and potentially predictive biomarkers of TRAIL sensitivity in human TNBC. First, gp78, an ubiquitin ligase that facilitates endoplasmic reticulumassociated protein degradation, was found to negatively regulate TRAIL-induced caspases-3/7 activity and loss in viability independently of the unfolded protein response in the TNBC mesenchymal cell line MB231. Second, TNBC cell lines sensitive to drozitumab, a TRAIL pathway agonist, were found to express the mesenchymal markers vimentin and Axl. Vimentin and Axl were determined to be co-expressed in a publically available cDNA microarray dataset and by immunohistochemistry in human TNBC. These findings provide insight into a novel gp78-associated mechanism that governs sensitivity to TRAIL-induced apoptosis in breast cancer cells and demonstrate that the proteins vimentin and Axl may predict sensitivity to a TRAIL pathway agonist in TNBC and are identifiable in human TNBC, which reflects their potential utility in identifying patients who may benefit from a TRAIL pathway agonist. Collectively, these findings may aid in the selection of appropriate combinatorial therapies and the identification of TNBC-affected patients for treatment with a TRAIL pathway agonist.
The long-term impacts of forest removal on
floodplain subsurface hydrology
Authors:   , Kellner Ramsey
   Elliott
Published: April 2021

A study
was implemented in fall 2010, in the Hinkson Creek Watershed, Missouri, USA to improve
quantitative understanding of the long-term impact of forest removal on floodplain
hydrology. Automated volumetric water content (VWC) probes and piezometers equipped with
pressure transducers to monitor shallow groundwater (SGW) temperature and level were
installed in a gridded study design within a historic agricultural field (Ag) and a remnant
bottomland hardwood forest (BHF). Groundwater was analyzed for 49 physiochemical metrics.
Results showed VWC to be significantly different between sites (p less than 0.01) during the
study, with site averages of 33.1 and 32.8% at the Ag and BHF sites, respectively.
Semi-variogram analyses results suggest historic forest removal and cultivation of the Ag
site facilitated the development of strong VWC spatial dependency. SGW temperature range at
the Ag site was 72% greater than at the BHF site. BHF groundwater contained significantly (p
less than 0.05) higher concentrations of nutrients, while Ag groundwater was characterized
by significantly (p less than 0.05) higher concentrations of trace elements. Collective results highlight the greater extent to which BHF vegetation impacts subsurface hydrology, relative to grassland/agricultural systems, and point to the value of reestablishing floodplain forests for freshwater routing, water quality, aquatic ecosystem conservation, and flood mitigation in mixed-land-use watersheds.
Characterizing the retroviral envelope glycoprotein membrane proximal external region and membrane-spanning domains for their roles in helical alignment, fusogenicity, and incorporation into viral particles.
Authors:   , Salamango Daniel James
Published: April 2021

Viruses use surface proteins to gain access into target cells to initiate infection. How these surface proteins make it into assembling viral particles and the exact details of the entry process are poorly understood. My work here provides insight into how Murine Leukemia Virus (MLV) acquires its surface protein and how this surface protein initiates entry into the target cell. I have identified that two domains in the surface protein dictate its ability to be acquired by the virus. Further, I have identified that four specific amino acid residues in a specific domain of the protein significantly contribute to the entry mechanism
Wettability and nanostructure effect on oscillating heat pipes
Authors:   , Zhang Feng Zhao
Published: April 2021

As electronics technologies rapidly develop with a demand for more power and miniaturization, effective thermal management of these systems becomes much more important. The oscillating heat pipe (OHP) is a promising highly efficient heat transfer device that is great for high heat flux applications common in the electronics industry. In the current investigation, the wettability effect on the heat transfer performance of OHPs has been conducted. 1). The overall performance of configuration of hydrophilic evaporator/ hydrophobic condenser and hydrophobic evaporator/ hydrophilic condenser was worse than the nontreated OHP, however; the oscillations were much damper when comparing the amplitudes. 2). High oscillating motion occurs in the OHP with the hydrophilic surface while low oscillating motion occurs in the untreated OHP. 3). A mathematical model shows that contact angle increases the oscillating motion decreases. 4). A theoretical model predicting operating limit is developed. Results show that radius and charging ratio has a large effect on the maximum heat transfer limit. Working fluids changes the operating limit.
Russian old believers in Alaska : linguistic and cultural continuity of traditionalist refugees
Authors:   , Bass April Renee
Published: April 2021

For two centuries, Russian Old Believers existed as religious refugees in search of a permanent and tolerant home; one group of Old Believers made their way to the United States. However, while these Old Believers found religious refuge in a nation with vacillating tolerance of religious freedom, they encountered new complications of cultural and linguistic pressures and temptations to assimilate -- particularly for their children. In an attempt to continue passing on the language and culture they had preserved from the 17thcentury, a few families established a geographically isolated, closed community in South Central Alaska (SCAK) that grew into a Village with different ways of adapting to the American culture outside. In evaluating how well SCAK Old Believers have maintained 17th-century traditional (i.e., passed from parent to child) language and culture I found that: 1.) the community has surpassed the third-generation language shift paradigm that most refugees and immigrants to the United States succumb to; 2.) overt expressions of religiosity quantifiably distinguish Old Believers from their non-Old Believer counterparts in the Village, which indicates that high-fidelity transmission still occurs; and 3.) traditional transmission is still positively influencing community retention (i.e., population maintenance). Additionally, I found that significant Village events initiated specific differences in adaptations to the surrounding American culture at the individual level that had interesting effects on strategies and behavior at the group level. Not only is this research a significant contribution to further clarifying human behavior and cultural evolution. This research and these findings are timely and relevant as social justice for refugees and immigrants are at the forefront of many current national and global sociopolitical conversations. The SCAK Old Believers demonstrate that it is possible to maintain linguistic and cultural heritage within a dominant postindustrialized society, and their case reinforces the importance of choice for refugees and the value of life without fear.
Cyclotron produced nuclides for PET imaging and radiotracer studies
Authors:   , Brossard Thomas W.
Published: April 2021

Sucrose was labeled at three different positions with radioactive fluorine, F-18, and applied to corn plants to study the transport of sugar in maize and to better understand the basic transport mechanism. The transport of sucrose in wild-type and mutant, lacking the primary sucrose transporter, plants were compared to each other and to sucrose labeled with carbon-14. It was found the fluorosucrose analogues compared well with the carbon-14 sucrose and a distinct difference was observed between the wild-type and mutant maize plants. The simultaneous production of copper-64 and zirconium-89 on a medical grade cyclotron, particle accelerator, was also explored. The targetry of the solid target holder of the cyclotron was modified by replacing a Havar window with a yttrium foil. This allowed for the production of zirconium-89 at the yttrium foil while allowing the enriched nickel-64 target to remain in the solid target holder for the production of copper-64. Zirconium-89 was produced, separated, purified and labeled with results similar to previous publications by other authors. The copper-64 production was enhanced by fifty percent when the yttrium foil was replacing the Havar window when compared to a database of over 40 productions at the Missouri University Research Reactor, MURR. The copper-64 was also separated, purified and labeled successfully by researcher at MURR.
Topics in geometric analysis and harmonic analysis on spaces of homogeneous type
Authors:   , Alvarado Ryan
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The present dissertation consists of three main parts. One theme underscoring the work carried out in this dissertation concerns the relationship between analysis and geometry. As a first illustration of the interplay between these two branches of mathematics we develop a sharp theory of Hardy spaces in the setting of spaces of homogeneous type. The presented work is in collaboration with M. Mitrea. In the second part, we prove that a function defined on a subset of a geometrically doubling quasi-metric space which satisfies a Holder-type condition may be extended to the entire space with preservation of regularity. The proof proceeds along the lines of the original work of Whitney in 1934 and yields a linear extension operator. A similar extension result is also proved in the absence of the geometrically doubling hypothesis, albeit the resulting extension procedure is nonlinear in this case. This work is done in collaboration I. Mitrea and M. Mitrea. In the final part of the dissertation we prove that an open, proper, nonempty subset of Rn is a locally Lyapunov domain if and only if it satisfies a uniform hour-glass condition. Additionally, we prove a sharp generalization of the Hopf-Oleinik boundary point principle for domains satisfying a one-sided, interior pseudo-ball condition, for semi-elliptic operators with singular drift. These results have been obtained in collaboration with D. Brigham, V. Maz'ya, M. Mitrea, and E. Ziade.
Molecular dissection of a genome defense pathway in Neurospora crassa
Authors:   , Boone Erin C.
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Meiotic silencing by unpaired DNA (MSUD) is an RNA interference (RNAi) pathway in Neurospora crassa that detects genes without a homologous partner and silences them for the duration of sexual development. In this study, we have further elucidated the function of known MSUD proteins, identified novel proteins that are required for MSUD, and demonstrated the conservation of RNAi-related processes at the nuclear periphery. We began by showing SAD-2 is crucial for the localization of other MSUD proteins in the perinuclear region. These data suggest that SAD-2 works as a scaffold protein and that proper function of MSUD, like other germline RNAi-like systems, is reliant on the presence of silencing proteins in the perinuclear region. An MSUD suppression assay identified two novel MSUD proteins, SAD-Y and SAD-B'. Even though SAD-Y and its homologs contain a conserved putative RNA- binding motif, they have yet to be assigned to a biochemical pathway. Our work here has linked silencing to SAD-Y-like proteins. SAD-Y has been shown to interact with other MSUD factors in both the nucleus and at the nuclear periphery. SAD-B's homolog has been found in the nuage, an epicenter for RNA-binding proteins involved in post-transcriptional regulation for Drosophila germline cells. SAD-B interacts with core MSUD proteins and has an especially intimate association with SMS-2, which requires it for localization. Furthermore, bimolecular fluorescence complementation (BiFC) revealed that SAD-B' interacts with a Golgi retrograde transport protein and an autophagy marker protein, suggesting the importance of the endomembrane system in this RNAi process.
Three essays on inside debt
Authors:   , Rajkovic Tijana
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This dissertation is composed of three essays examining inside debt. The first essay tests the impact of inside debt on security issuance decisions. I find that CEOs with high debt incentives are more likely to issue equity that debt, unlever firm capital structure, and hold debt of longer average maturity. The results indicate that managers with high debt incentives favor financing decisions that decrease firm risk. The second essay examines the determinants of use and magnitude of inside debt. I find a positive association between inside debt and CEO talent. In addition, I find that inside debt affects the likelihood of CEO post-retirement board service and CEO successor characteristics. The third essay examines the impact of inside debt on corporate dividend policy. I find that companies with large CEO holdings of inside debt are more likely to pay and increase dividends, and have larger dividend payouts. The results indicate that inside debt, by reducing firm risk, positively influences corporate dividend policy.
Unconventional oil and gas extraction as a novel source of endocrine disrupting chemicals to water and the potential for adverse human and animal health outcomes
Authors:   , Kassotis Christopher Dennis
Published: April 2021

The proper and unimpeded function of hormones is essential for normal development, maturation, and prevention of chronic diseases. Endocrine disrupting chemicals (EDCs) are exogenous chemicals that have been found to disrupt a number of receptor systems with adverse outcomes associated at environmentally relevant exposure levels. This body of work discusses a novel source of exposure to EDCs: unconventional oil and natural gas extraction operations utilizing hydraulic fracturing. Twenty-four hydraulic fracturing chemicals were tested for agonist and antagonist activities for five nuclear receptors, with the majority exhibiting antagonist receptor activities. Elevated estrogen and androgen receptor activities were measured in surface and ground water from drilling-dense sites with known spills, suggesting a route of potential human exposure. Lastly, increased body weights, organ weights, and decreased sperm counts were exhibited by male C57BL/6J mice exposed prenatally to a mixture of these chemicals in drinking water. In total, this work highlights a novel route of exposure to EDCs and suggests a potential threat to human and animal health in areas where these operations occur.
Two empirical analyses of the minimum wage impacts on employment
Authors:   , Liu Yandi
Published: April 2021

"The contentious debates regarding minimum wages have produced little agreement so far on the extent to which it affects employment. The dissertation intends to provide a better understanding of minimum wage impacts on employment. The literature review considers both the theoretical models and empirical studies, as well as providing a detailed examination of their methodologies. Two empirical studies form the core of the dissertation. One study estimates the minimum wage impacts using state-level CPS data from 1979 to 2011 in a panel regression framework. The other study explores a natural experiment due to a legislated increase of the minimum wage in Missouri but not in Kansas. Comparing firms in the Kansas City metropolitan area on both sides of the state boundary, the analysis considers minimum wage effects at both the firm-level and individual-level for various groups of firm sizes and different earners. The analysis is performed on multiple selected broad industries. This dissertation finds that in general minimum wage reduces total employment. However, the impacts of minimum wage policy do vary substantially across industries and across groups. Firms with no more than 10 employees and new firms are more likely to experience increase in employment with the increase of minimum wages. In addition, due to substitution effects, people with wages above the minimum wages could get increased chance of being employed from this policy. In contrast, most of the estimates for people who work very few hours are insignificant. However, in the industries with higher proportions of low wage workers, that is, in retail trade and food industries, the probability of being employed for these employees is reduced. The
major policy implication is that our empirical findings throw light on the importance of distinguishing between industries and between workers with different earnings."
A team is only as good as its people: the impact of individual supply chain member success on the cross-functional teams success in the global apparel supply chain
Authors:   , McAndrews Laura Ellen
Published: April 2021

The global apparel supply chain has been transformed by many factors including globalization and fragmentation resulting in a hyper-dynamic market full of uncertainty and volatility (Dyer and Ha-Brookshire, 2008). In managing global supply chains, cross-functional teams have become increasingly important in organizations to improve innovation and coordination and to reduce time spent on new product development and fulfillment (Denison, Hart, and Kahn, 1996). This research study was designed to investigate the relationships between successful intelligence, emotional intelligence, job satisfaction, and career success on individual supply chain members and how that may affect cross-functional teams' success within the global apparel supply chain. To achieve the objective the study collected 135 responses from global apparel supply chain members using an online survey and then analyzed the data using SEM, path analysis. The study's results supported the relationship of emotional intelligence, job satisfaction, and subjective career success on the cross-functional team's success. However, successful intelligence was not found to be a significant variable for this sample. Finding can be used by apparel organizations in developing and facilitating emotional intelligence in the work environment to assist with cross-functional team success.
Energy transfer and gas diffusion at gas-liquid interfaces
Authors:   , Shaughnessy Daniel J.
Published: April 2021

The interactions of gasses and liquids play an important role in many systems in chemistry. Gas-liquid surface scattering techniques are a useful tool towards the investigation of energy transfer resulting from gas-liquid collisions. We use molecular dynamics to simulate surface scattering in order to investigate the effects of incident energy, incidence angle, and surface temperature on energy transfer of a CO2 molecule scattering from a liquid indium surface modeled as a simple Lennard-Jones liquid. We focus our investigation on the two-channel theory of gas-liquid scattering with a primary focus on the trapping-desorption scattering channel. We use a novel technique to investigate the average trajectory of the scattering gas species to determine the effects of energy transfer on this channel. We find species scattering via this channel are unaffected by incident energy and incidence angle in agreement with experimental trends. We find our gas species scattered by the trapping desorption channel emerge with four degrees of freedom thermalized to the surface temperature, with substantial variance in the translational degree of freedom in the surface normal direction which we attribute to both the enthalpy of desorption and interactions with vapor-phase indium atoms. We observe a substantial increase in interactions with vapor-phase indium with increasing temperature. Our second simulation uses molecular dynamics to examine the diffusion of various gas species through a room temperature ionic liquid at standard pressure conditions. We were able to replicate the bulk properties of the bmim PF6 ionic liquid with reasonable accuracy compared with other experimental and theoretical work. We varied the gas species mass, the gas species dipole moment, and the ionic liquid temperature to examine the effects of each variable on gas diffusivity. We find a general trend of increased diffusivity with increasing temperature; however, we are unable to discern a definite trend relating to gas species mass or dipole moment. We observe significant short-time trapping effects on our diffusing gas species, particularly at low temperatures, that make examining the diffusivity of our gases problematic.
A ballooned beta-logistic model
Authors:   , Yi Min
Published: April 2021

The beta distribution is a simple and flexible model in which responses are naturally confined to the finite interval (0,1). Its parameters can be related to covariates such as dose and gender through a regression model. The Ballooned Beta-logistic (BBL) model expands the response boundaries from (0,1) to (L,U), where L and U are unknown parameters. Under the BBL model, expected responses follow a logistic function which can be made equal to that of the Four Parameter Logistic (4PL) model. But the distribution of responses differs from the classical 4PL model which has additive normal errors. In contrast, the BBL model naturally has bounded responses and inhomogeneous variance. The asymptotic normality of maximum likelihood estimators (MLEs) is obtained even though the support of this non-regular regression model depends on unknown parameters. We find MLEs converge faster to L and U than do extreme values at the minimum and maximum concentrations. Given enzyme-linked immunosorbent assay data from different plates, we study a motivating validation objective, which is to set suitability criteria for estimates of L and U; after this plates with boundary estimates outside these limits would be considered â€reference failuresâ€. We show the BBL model has advantages over the 4PL model.
Simulation aided analysis of polyurethane reaction systems
Authors:   , Ghoreishi Rima
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Numerous reactions take place within a polyurethane polymerization process. Homogeneous and catalytic reactions occur at the same time and intermediate compounds are formed. As the reaction proceeds, long chains of polymer are formed which drastically affect the kinetics of the reaction. Temperature and viscosity profiles of the reacting mixture are two strong indicators of the extent of reaction and the way the reactions are carried out. Therefore, simulating polyurethane gel and foam systems helps interpret temperature and viscosity profiles and gain insight into the kinetics of the system. Using MATLAB program, a model was introduced which simultaneously solves over 80 ordinary differential equations and provide temperature and viscosity profiles as well as concentration profiles, degrees of polymerization, gel point and foam height for individual formulations. Experimental data was used to validate the code showing the model is fundamentally correct. Simulation results showed good fits to the experimental data providing reaction kinetics of the system. The model was modified to simulate reaction systems with minimal change in kinetic parameters. The model successfully simulates polyurethane polymerization process for both bio-based and petroleum-based polyols. A different version of the code also simulates the formation of bio-based polyols from epoxidized soybean oil.
Teacher burnout in Japan : relationships with individual teacher and classroom level factors
Authors:   , Fujiki Mayo
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The current study employed factor analyses, structural equation modeling, and correlations in order to examine relationships among teacher burnout, teaching efficacy, and classroom students' academic and behavioral problems with Japanese elementary and junior high samples and the structures of each measure. A total of 463 teachers in Japan answered a set of questionnaires both in early and later school year. Through classroom observations at 35 elementary schools, the teachers' uses of proactive and reactive behavior management strategies as well as classroom students' problems were collected. The results of factor analyses confirmed the three-factor structures of the Maslach Burnout Inventory (MBI) and Teacher Sense of Self Efficacy Scale- Short Form (TSSES- Short Form) with both the elementary and junior high samples; however, the factor structures of the students' problem measure differed by the school levels. While a direct path between early school year students' problem and later teacher burnout was not found with junior high sample, it was found with elementary sample. No mediated relationship was found as teaching efficacy as a mediator. The final model also differed by the school levels. No correlation was found between observed and teacher reported variables. Implications and future research concerning teacher burnout are discussed.
Partially informative normal and partial spline models
Authors:   , Liu Sifan
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] There is a well-known Bayesian interpretation of function estimation by spline smoothing using a limit of proper normal priors. This limiting prior has the same form with Partially Informative Normal (PIN), which was introduced in Sun et al. (1999). In this dissertation, we first discuss some properties of PIN. In terms of improper priors, we consider q-vague convergence as the convergence mode. Then, we apply the properties to several extensions of smoothing spline problems. Partial spline model, which contains a non-parametric part as regular smoothing spline together with a linear parametric part, is discussed. We perform simulation studies and applications on yield curves. Specifically, Nelson-Siege (NS) model is considered to construct the linear component. NS partial spline model is used for fitting single yield curve, while partial parallel and non-parallel spline models are used for multiple curves. Then, large p, small n regression problem associated with the generalized univariate smoothing spline, some studies on bin smoothing splines, adaptive smoothing splines and correlated smoothing splines are discussed.
Climate change in the Missouri central hardwood region : consequences for forest landscapes, and management strategies
Authors:   , Schneiderman Jeffrey Eric
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Climate change may result in a change in the tree species present within forests. The Missouri Central Hardwood Region represents one area where these changes may occur. Due to the natural diversity of species and economic value of this area, it is beneficial to understand how climate change might affect trees currently present. Computer models (a human creation to help understand real world systems in a simplified manner) can be used to study the impact of climate change on forests. My objectives were to 1) understand how different forest impact models studying climate change compared to each other, 2) determine whether climate change or current timber harvest practices was more likely to change the characteristics of the forest, and 3) analyze land management alternatives to determine which was best at creating beneficial qualities for forests under climate change. For my first objective, I used a species distribution model and a process model, two models that use different analysis approaches, to assess climate change impacts on tree species, and compared the results. On a broad level, both models agreed, but when looking at the study area at smaller resolution, the models did not agree as well. For my second objective, I coupled a process model and forest landscape model. Although results showed there was variation based on species regarding whether climate or harvest had the greater impact, both usually had significant impacts on tree species. Results for my third objective indicated that multiple management approaches are necessary to manage future forests in a beneficial manner. My results have implications for future forest sustainability. Uncertainty exists regarding climate change's full impact, but with proper forest management and research these challenges can be reduced.
Monitoring membrane protein structural changes and interactions via deep UV resonance Raman spectroscopy
Authors:   , Brown Mia C.
Published: April 2021

Membrane proteins perform a variety of functions within our cells. They transport nutrients and waste across the lipid barrier, transmit signals from one part of the body to another, and run our immune system. However, despite their ubiquitous and vital presence in all organisms, relatively little is known about this class of proteins compared to their soluble counterparts. Intramembrane proteolysis is a process involving membrane proteins that occurs in all biological organisms and has garnered particular interest due to its involvement in various disease pathologies, such as Alzheimer's and Parkinson's Diseases. In this work I have set out to use deep UV resonance Raman (DUVRR) spectroscopy to characterize structural and environmental transitions of proteins and applied the results to studies involving intramembrane proteolysis in an effort to better understand the key concepts behind it.
Determining the impact of usability issues of primary care physicians by expertise when using an electronic health record
Authors:   , Clarke Martina A.
Published: April 2021

Background: EHRs with poor usability present steep learning curves for new resident physicians, who are already overwhelmed in learning a new specialty. This may lead to error prone use of EHR in medical practice by new resident physicians. The goal of this study is to identify usability-related and performance-related differences that arise between primary care physicians by expertise when using an EHR. Methods: We compared usability measures after three rounds of usability tests Lab-based usability tests using video analyses were conducted to analyze learnability gaps between novice and expert physicians. Physicians completed nineteen tasks, based on an artificial but typical patient visit note. We used a mixed methods approach including quantitative performance measures (percent task success, time on task, mouse activities), a survey instrument: system usability scale (SUS), qualitative narrative feedback during the debriefing session, subtask analysis, and debriefing session with physicians. Results: Geometric mean values of percent task success rates, time on task, and mouse activities were compared between the two physician groups across three rounds. Our findings show that there were mixed changes in performance measures and expert physicians were more proficient than novice physicians on some performance measures. Thirty-one common and four unique usability issues were identified between the two physician groups across three rounds. Five themes emerged during analysis: six usability issues were related to inconsistencies, nine issues concerning user interface issues, six issues in relation to structured data issues, seven ambiguous terminology issues, and six issues in regards to workarounds. Discussion and Conclusion: This study found differences in novice and expert physicians' performance, demonstrating that physicians' proficiency did increase with EHR experience. Future directions include identifying usability issues faced by physicians when using the EHR through a more granular task analysis to recognize subtle usability issues that would have otherwise been unnoticed. Also, exploring associations between performance measures and usability issues will also be studied. Training physicians to use the EHR may decrease difficulty of completing tasks in the EHR. Improving physician training may reduce the amount of workarounds created that may lead to workflow problems. These results highlight the areas of difficulty resident physicians with different experience levels are currently facing, which may potentially improve the EHR training program and increase physicians' performance when using an EHR.
Therapeutic and chemopreventive potential of luteolin against growth and metastasis of breast cancer
Authors:   , Cook Matthew T.
Published: April 2021

Breast cancer is the second leading cause of cancer-related death in older women. Many postmenopausal women undergo hormone replacement therapy (HRT) to alleviate the symptoms of menopause. Recent studies implicate the progestin component of HRT as being most likely responsible for elevated breast cancer risk and increased mortality. Using animal models and cell culture we explored the preventive and therapeutic potential of luteolin (LU), a naturally-occurring compound found commonly in fruits and vegetables, and examined its ability to both prevent the onset of breast cancer, and inhibit its growth and metastasis. LU effectively blocked progestin (P)-induced intratumoral vascularization in our animal models when given preventatively or therapeutically. LU blocked P-stimulated effects in cultured human breast cancer cells, including inhibiting the enrichment of a subpopulation of human breast cancer cells that are believed to be responsible for tumor initiation. Such cells are difficult to treat by conventional methods. Progestins not only elevate the risk of breast cancer in postmenopausal women but have also been implicated in making tumor cells metastatic, increasing their ability to spread from the breast to distant sites around the body. With this in mind we utilized a hormone-independent model of lung metastasis, since most hormone-dependent cancer cells ultimately become hormone-resistant and lose therapeutic markers. LU significantly reduced the formation of lung colonies arising from these human breast cancer cells, with little or no animal toxicity. Overall, these studies provide compelling evidence that LU possesses chemopreventive, therapeutic, and anti-metastatic properties which might be harnessed to combat breast cancer.
A landscape-scale assessment of the response of birds to land cover, climate, and forest management
Authors:   , LeBrun Jaymi J.
Published: April 2021

Climate change will likely increase temperatures across the globe as well as alter regional climates. These climate shifts have the potential to substantially change vegetation and reshape both plant and animal distributions. To mitigate these potential changes, scientists have suggested management strategies focused on forest resilience, response, and carbon sequestration. The goal of this research was to determine the current impacts of land cover and regional climate on birds in the Midwest, and use these current relationships to assess the direct and indirect effects of future climate and management on avian abundance in Missouri. I coupled the Bayesian model with a landscape simulation model (LANDIS PRO) to predict bird abundance 100 years into the future for a range of climate and forest management scenarios. Forest and canopy cover were the primary drivers of current bird abundance, however, temperature was influential for early successional species. In addition, the most significant climate related effect was for the northern bobwhite with higher abundances under warmer winters. For most birds, management had a greater impact on future abundance than climate, however, species currently exhibiting direct effects of climate showed compounded effects associated with management. Even though we expect land cover to change very little due to climate, we did see one bird (i.e., northern bobwhite) affect by climate-induced changes to vegetation. Managing forest cover will be key for mitigating the effects of future climate for birds.
Chlorine and singlet oxygen photoelimination from organoplatinum(IV) complexes
Authors:   , Perera Tharushi A.
Published: April 2021

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Solar energy is the most promising carbon neutral energy source for the future. Splitting of simple molecules like HX (X = Cl, Br) has become an attractive way to convert and store solar energy. Halogen photoelimination from metal centers is the most challenging step in photochemical HX splitting cycles. We have synthesized Pt(IV) chloro complexes trans -Pt(PEt3)2R(Cl)3 (R = Cl, aryl and PAH fragments), which eliminate chlorine in the presence of halogen traps when irradiated with uv-vis light. The photo-efficiency of Pt--chloride bond activation increases in the presence of Pt(II) complexes trans -Pt(PEt3)2R(Cl) suggesting the absence of molecular chlorine from reductive elimination of Pt(IV) chloro complexes. Also, we propose that the mechanism of halogen photoelimination from Pt(PEt3)2X3R (X = Cl, Br) (R = aryl, Cl, PAH) complexes is cis elimination via radical abstraction. Synthesis, characterization and photochemistry of a new Pt(IV) carbene pincer hydroperoxo hydroxo complex is described. This complex is highly active photochemically showing 1280% quantum yield and eliminates singlet oxygen and water under ultraviolet light. The photoelimination of singlet oxygen in 86% yield from Pt(IV) carbene pincer hydroperoxo hydroxo complex can be considered as a new route to activate ground state oxygen to excited state oxygen which is vital for complex biological studies.