Computational Investigations Of The Photochemical Properties Of B12-Dependent Systems: From Solution To Enzymes., Megan Toda Mackintosh

Electronic Theses and Dissertations

The photochemical properties of the B₁₂ family of molecules (cobalamins = Cbls) have been known for many years yet only until the 21^st century have applications for the light-sensitivity of Cbls come to the surface. Photolabile Cbls can be used for the delivery of therapeutics with spatial and temporal control, in the generation of hydroxyl radicals, and in nature, as demonstrated in the catalytic cycle of coenzyme B₁₂-dependent photoreceptors. This dissertation describes the use of computational methods to explore the photochemical properties of Cbl systems including antivitamins B₁₂, a thiolato-cobalamin, and the coenzyme B …

A Practical Extension To The Ab/Ba Design, My T.A Nguyen

Electronic Theses and Dissertations

In this work, we take a close look at a general extension to the traditional AB/BA
crossover design that is commonly used in clinical trials to determine the effectiveness
of new candidate drugs. While the traditional crossover design requires each patient
in the study to be measured on both treatment A and treatment B, we consider the
possibility of additional measurements being available on each patient. This produces
designs such as the AABB/BBAA design which has been used in previous studies.
A general test statistic will be derived to test for treatment effects as well as its
corresponding power function …

Soil Gypsum Content Analysis Of The Proposed Road Route Extension Of Fm 2185 In The Gypsum Plain, Culberson County, Texas, Chikaodili Ohakawa

Electronic Theses and Dissertations

Soils serve as the underlying substrate on which foundations for most structures are built. The properties of a soil type are therefore an important consideration in building engineered structures. Gypsic soils are problematic for construction of such structures. One of the main problems with gypsic soils is dissolution. Gypsum (CaSO₄·2H₂O) in soils dissolves easily creating voids which can be detrimental to the integrity of engineering structures. To mitigate this, it is important to determine the amount of gypsum present in soils, before construction is initiated.

In this study, three methods were employed in the determination of …

Computational Analysis Of The Spin Trapping Properties Of Lipoic Acid And Dihydrolipoic Acid, Matthew Bonfield

Electronic Theses and Dissertations

While the spin trapping properties of thiols have been investigated through EPR analysis and kinetics studies, few groups have studied these properties using strictly computational methods. In particular, α-lipoic acid (ALA) and its reduced form, dihydrolipoic acid (DHLA), one of the strongest endogenously produced antioxidants, show potential for being effective, naturally occurring spin traps for the trapping of reactive oxygen species. This research covers electronic structure calculations of ALA, DHLA, and their corresponding hydroxyl radical spin adducts, performed at the cc-pVDZ/B3LYP/DFT level of theory. The effects on DHLA introduced by other radicals such as ·OOH, ·OCH₃, …

Electronic Evidence Locker: An Ontology For Electronic Evidence, Daniel Smith

Electronic Theses and Dissertations

With the rapid growth of crime data, overwhelming amounts of electronic evidence need to be stored and shared with the relevant agencies. Without addressing this challenge, the sharing of crime data and electronic evidence will be highly inefficient, and the resource requirements for this task will continue to increase. Relational database solutions face size limitations in storing larger amounts of crime data where each instance has unique attributes with unstructured nature.

In this thesis, the Electronic Evidence Locker (EEL) was proposed and developed to address such problems. The EEL was built using a NoSQL database and a C# website for …

Preparation And Study Of Bacterial Membrane Models, Enoch Asimbisa

Electronic Theses and Dissertations

Fuel molecules are organic solvents that have disruptive effects on the bacterial membrane. This is a significant barrier in biofuel production, as it limits the fuel concentration that can be achieved through fermentation. One potential way of overcoming this barrier is to identify lipid compositions that can better withstand solvent stress, for which it is important to understand how organic solvents disrupt the membrane. Use of biophysical characterization techniques to quantify physical properties like fluidity and thickness will enable us to understand the mechanism by which solvents disrupt membranes. Native membranes are very complex, and we sought to develop in-vitro …

Functional Mixed Data Clustering With Fourier Basis Smoothing, Ishmael Amartey

Electronic Theses and Dissertations

Clustering is an important analytical technique that has proven to affect human life positively through its application in cancer research, market segmentation, city planning etc. In this time of growing technological systems, mixed data has seen another face of longitudinal, directional and functional attributes which is worth paying attention to and analyzing. Previous research works on clustering relied largely on the inverse weight technique and B-spline in smoothing data and assessing the performance of various clustering algorithms. In 1971, Gower proposed a method of clustering for mixed variable types which has been extended to include functional and directional variables by …

Synthesis Of Phosphatidylethanolamine Lipids For Model Studies Of The Cell Membrane, John Hayford G. Teye-Kau

Electronic Theses and Dissertations

Concerns about global warming have resulted in a surge of research into alternatives to fossil fuels. In recent years, biofuels have gained traction due to their low environmental impact. Biofuel production most commonly employs microorganisms to convert biomass to fuel for industrial and transportation applications. Compounds made in biofuel production, however, are toxic to cell membranes and disrupt their integrity, harming the microorganisms and limiting biofuel yield. A key to overcoming this challenge is understanding how fuels interact with microorganisms’ cell membranes, which perform a host of functions, including transport, cell recognition, transduction, and movement. Phospholipids are the cell membrane’s …

Student Collaboration: Early Childhood Teachers' Roles And Perspectives, Kimberly Ballantyne

Electronic Theses and Dissertations

Early childhood environments can offer valuable opportunities for student collaboration. Social interactions allow students to practice listening to each other and learn how to work together. This study focused on the roles and perspectives of early childhood educators related to student collaboration in the classroom. Six educators from one elementary school in New Hampshire participated in two focus group discussions, the first of which included a presentation on student collaboration with first graders. Participants also completed four concept maps highlighting their perspectives about student collaboration and one written reflection comparing their perspectives before and after engaging in the focus group …

Synthesis Of Phytosulfokine Analogs As Probes For Studying Plant Signaling And Molecular Trafficking, Thomas Ntim

Electronic Theses and Dissertations

Plants are exposed to a wide range of biotic and abiotic stresses that hinder their growth and reduce crop productivity. In their adaptive response, plants use signaling molecules that are trafficked throughout the plant. This research focuses on the chemical synthesis and assessment of analogs of the plant signal phytosulfokine (PSK, a sulfated pentapeptide), its delivery to plants and its observation using a fiber-optic fluorescence microscope. PSK regulates growth, cell expansion, heat tolerance, and tissue longevity. Analogs of PSK were synthesized using solid-phase peptide synthesis. Pure PSK and TAMRA-labeled PSK were delivered into the wild-type Arabidopsis thaliana Col-0 and a …

Facile Nitrogen-Doping Of Screen-Printed Carbon Electrodes For Detection Of Hydrogen Peroxide, Emmanuel Nkyaagye

Electronic Theses and Dissertations

Screen-printed carbon electrodes (SPCEs) have garnered much attention as sensors due to their simplicity and relatively low cost. However, to impart necessary selectivity and sensitivity for specific applications, modification of the SPCE surface, which can involve time-consuming procedures or costly equipment/materials, is typically required. Here, a simple nitrogen-doping process based on NH₄OH was used to modify SPCEs prepared from commercially available ink for electrochemical detection of H₂O₂, a common target for biosensing strategies and indicator of cell stress. XPS studies showed that NH₄OH treatment of SPCEs led to a nearly 5-fold increase …

Exploring Integration Between Athletic Trainers And Strength And Conditioning Coaches Among The Ncaa Division I Southern Conference Institutions, Yoshihiro Kojima

Electronic Theses and Dissertations

The purpose of this study was to explore the interdepartmental integration between athletic trainers and strength and conditioning coaches in relation to relationship, communication, collaboration, and education. Forty participants from the NCAA Division I Southern Conference, twenty-eight athletic trainers and twelve strength and conditioning coaches, completed an electronic survey during a two-week period. Collected data were analyzed by descriptive and thematic coding analyses. The results suggested participated athletic trainers and strength and conditioning coaches were interactive and collaborative. Open-ended responses identified key concepts when athletic trainers and strength and conditioning coaches communicated and collaborated. A high interaction and collaboration model …

Racial Diversity Of Texas School Teachers, Julie Ann Olguin-Phillips

Electronic Theses and Dissertations

There is a growing gap between the racial demographics of public-school teachers and their students. Teachers with demographic backgrounds similar to a school’s student population are often successful, particularly in Title 1 schools with high proportions of minority students; however, teacher turnover is high. The students in Texas public schools are a growing minority-majority population. Changes in the student body racial composition and other school-related variables could influence teacher workforce demographics. The focus of discussion of this quantitative research study is to determine the factors that predict the racial diversity of teachers in Texas high schools. The research questions addressed …

Synthesis, Crystal Structure And Ionic Conductivity Of Ruddlesden-Popper Oxide Materials: Effects Of Ionic Radii And Defects On Lithium-Ionic Conductivity., Selorm Joy Fanah

Electronic Theses and Dissertations

Layered perovskite oxides of the Ruddlesden-Popper (RP) type structure can be good lithium-ion conductors for solid electrolyte applications in all-solid-state batteries, due to the large gap separating octahedral layers which can be useful pathways for Li-ion conduction. However, little work has been done on their lithium-ion transport properties in these materials despite their interesting structural properties. This work highlights the synthesis and study of the ionic conductivities in a series of n = 2 and 3 Ruddlesden-Popper oxides, as part of an ongoing investigation in search of alternative solid electrolyte materials. Several different strategies were employed for the enhancement of …

Towards Long Term Colloid Suspension In A Vertically Rotated System., Md Mahmudur Rahman

Electronic Theses and Dissertations

Within a colloidal suspension gravity may compromise the observation of governing physical interactions, especially those that are weak and/or take significant time to develop. Conducting the experiment in a long-term microgravity environment is a viable option to negate gravitational effects, though significant resources are required to do so. While it may not be possible to simulate long-term microgravity terrestrially, particles can resist quick sedimentation in a confined suspension system rotating vertically with appropriate rotation speed. The goal of the investigation is to demonstrate the existence of long-term particle suspension regime for a certain colloidal suspension while characterizing colloidal behavior due …

Ultrafast Magnetic Entropy Dynamics With Time-Resolved Pump-Probe Magneto-Optical Technique., Sahar Goharshenasanesfahani

Electronic Theses and Dissertations

It has been observed that ultrathin films, multilayers, or magnetic nanostructures indicate novel magnetic phenomena that differ profoundly from the respective bulk properties. Besides, because of the broad applications of these magnetic materials in the industry, they are an exciting research area. Hence, investigating the low-dimensional magnetic systems is one of the most active fields in experimental condensed matter physics. Magnetization dynamics can occur over a wide range of time scales (from seconds to femtoseconds). Some of these processes even occur on time scales as short as a few picoseconds (10^-12s) or femtoseconds (10^-15s). Measurement of …

Local Feature Selection For Multiple Instance Learning With Applications., Aliasghar Shahrjooihaghighi

Electronic Theses and Dissertations

Feature selection is a data processing approach that has been successfully and effectively used in developing machine learning algorithms for various applications. It has been proven to effectively reduce the dimensionality of the data and increase the accuracy and interpretability of machine learning algorithms. Conventional feature selection algorithms assume that there is an optimal global subset of features for the whole sample space. Thus, only one global subset of relevant features is learned. An alternative approach is based on the concept of Local Feature Selection (LFS), where each training sample can have its own subset of relevant features. Multiple Instance …

First Principle Studies Of The Effects Of Alkali-Metal Intercalation On Structural Transition From Black To Blue Phosphorene And The Adsorption Of N2h4 On Ws2 Layers., Md Rajib Khan Musa

Electronic Theses and Dissertations

A comprehensive density functional theory calculation has been conducted to seek a potential structural transition from black to blue phosphorene layers, with a focus on the roles played by alkali-metal intercalation in black phosphorene/phosphorus. This study reveals that at sufficiently high Li concentration and specific, well-defined configurations, a phase transition from black to blue phosphorene can take place. The Li atoms intercalated in black phosphorene could act as a “catalyst” in the“reactive region” of the lone pair of P atoms, leading to a P-P bond breaking and, subsequently, a local structural transformation from an orthorhombic lattice to an assembly of …

A Remote Sensing Perspective: Mapping The Human Footprint In The Zambezi Region Of Namibia., Ariel E Weaver

Electronic Theses and Dissertations

The “human footprint” can be used as a general proxy to estimate human activities across the landscape. The human footprint in the Zambezi Region of Namibia is critically important for regional management of conservation efforts and land use planning. The land covers in the Zambezi Region are characteristically difficult to separate spectrally, due to a highly heterogeneous savanna landscape. Object Based Image Analysis (OBIA) and Random Forest (RF) methods are notable for their ability to improve classification accuracies of remotely sensed imagery. In this study, I investigate the extent of the human footprint in the Zambezi Region of Namibia, using …

Theoretical Investigation Of The Co-C Bond Activation In Methylcobalamin And Adenosylcobalamin-Dependent Systems: Mechanistic Insights., Arghya Pratim Ghosh

Electronic Theses and Dissertations

The vitamin B₁₂ derivates, otherwise known as cobalamin (Cbl), are ubiquitous organometallic cofactors. The biologically active forms of Cbl, such as methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl), act as cofactors in different physiological reactions for both prokaryotes and eukaryotes. A crucial aspect of the Cbl-mediated systems is the activation of the organometallic Co-C bond that plays a critical role in its catalytic activity. One of the most remarkable features of this Co-C bond is its unusual activation in AdoCbl-dependent enzymatic reactions, where a trillion-fold rate acceleration of the Co-C bond cleavage is observed inside the enzyme compared to the isolated …

Modeling Driver Distraction Mechanism And Its Safety Impact In Automated Vehicle Environment., Song Wang

Electronic Theses and Dissertations

Automated Vehicle (AV) technology expects to enhance driving safety by eliminating human errors. However, driver distraction still exists under automated driving. The Society of Automotive Engineers (SAE) has defined six levels of driving automation from Level 0~5. Until achieving Level 5, human drivers are still needed. Therefore, the Human-Vehicle Interaction (HVI) necessarily diverts a driver’s attention away from driving. Existing research mainly focused on quantifying distraction in human-operated vehicles rather than in the AV environment. It causes a lack of knowledge on how AV distraction can be detected, quantified, and understood. Moreover, existing research in exploring AV distraction has mainly …

Design Of A 300cm2 Pemfc Stack With Force And Cfd Simulation To Optimize Flow Channels, Gasket Design, And Clamping Forces., Robert M. Ench

Electronic Theses and Dissertations

Proton exchange membrane fuel cells are important to the future of green energy as hydrogen can be made with green technologies and store energy for later use. Fuel cells can efficiently convert the hydrogen to electricity as needed. This study uses Solidworks simulation to make design improvements to the fuel cell before the prototype build stage of testing; this saves money and time by reducing the prototype builds needed.

In this study, a multi-channel serpentine design with two outlets versus a single outlet is evaluated using CFD to investigate pressure drop. Lower pressure drops are desirable as less energy input …

Confidence Interval For The Mean Of A Beta Distribution, Sean Rangel

Electronic Theses and Dissertations

Statistical inference for the mean of a beta distribution has become increasingly popular in various fields of academic research. In this study, we developed a novel statistical model from likelihood-based techniques to evaluate various confidence interval techniques for the mean of a beta distribution. Simulation studies will be implemented to compare the performance of the confidence intervals. In addition to the development and study involving confidence intervals, we will also apply the confidence intervals to real biological data that was gathered by the Department of Biology at Stephen F. Austin State University and provide recommendations on the best practice.

A Phenomenological Study Examining How The Covid-19 Pandemic Changed The Way Teachers Use Technology To Deliver Instruction From March 2020 - May 2021, Dedra Lamb

Electronic Theses and Dissertations

The purpose of this qualitative study was to examine teacher perception of changes in the instructional delivery and learning opportunities via technology during and throughout the COVID-19 pandemic from March 2020 until May 2021. The COVID-19 pandemic has greatly affected educational organizations. School closures in March 2020 forced teachers to change their instructional delivery from an in-person platform to a virtual platform. This disruption to the delivery of instruction with the use of technology changed the way teachers plan for learning, delivery content, present learning activities, and assessment. The urgency required teachers to develop new strategies and experiment with adaptations …

Assessment Scores Of Remote And In-Person Learning For Grades Three - Six Students In An East Tennessee School District, Jessica Adams

Electronic Theses and Dissertations

The purpose of this comparative, quantitative study was to explore the relationship of interim test scores among remote and in-person learners, low-income students, and students with disabilities. In March 2020, a portion of students enrolled in a K-12 school in Northeast Tennessee was moved into remote learning until the end of the school year in May 2020. In July 2020, parents were given the option for their child to attend remote or in-person learning. While some chose in-person learning, giving reasons such as child-care, work obligations, or personal preference, others chose for their children to continue to receive online learning …

A Causal Comparative Study Of Stem Persistence Between Supported And Non-Supported Stem Interested Students, Elizabeth Bernardi

Electronic Theses and Dissertations

Many students who enter a STEM track in college move out of that track before graduation (National Science Foundation, 2018). The purpose of this study was to assess whether there was a difference in STEM-related major persistence for population proportions of students actively involved in the Science Scholars program and those who were STEM-interested but not program participants. This program oriented students to the STEM program, facilitated engagement with peers and faculty, exposed students to research opportunities, and filled in potential learning gaps (Gibson et al., 2019).

The questions guiding the current research included:

Q1. Was there a statistically significant …

Part-Time Enrolled Community College Students: A Case Study Examining The Experiences Of The Invisible Majority, Janelle M. Green

Electronic Theses and Dissertations

This qualitative research used multiple case study methodology to explore the perceptions and experiences of part-time enrolled students at multicampus urban community colleges in the Southwest region of the United States. Of particular interest was how students defined success and their perception of what it took to achieve success, the utilization rate of student success resources, challenges encountered that caused a student to consider stopping out, the quality of relationships and connections part-time students had with faculty and staff, and the experience students had navigating institutional systems and processes. This study was conducted at a large, public, urban, multicampus community …

Youth Leadership Development Programs: Participants’ Pre- And Post-Perceptions Of Leadership Life Skills Development, Courtney A. Pruner

Electronic Theses and Dissertations

Research exists on the participation of youth in various types of youth leadership development programs. However, the problem is a lack of understanding of the perception of participants’ pre- and postparticipation on their development of leadership life skills. The purpose of this quantitative, causal-comparative study was to determine how youth leadership development program participants perceive themselves in the area of leadership life skills development pre- and postparticipation in a youth leadership development program. In this study, specific consideration was given to the difference in gender and ethnic minority affiliation reporting scores. The independent variables in this study were participation in …

Detailed Structural And Stratigraphic Analysis Of The Salt-Sediment Interactions On Top Of The Wheeler Dome Salt Tongue, Mississippi Canyon Area, Gulf Of Mexico, Ryan Jaska

Electronic Theses and Dissertations

The Mississippi Canyon is in the northeastern part of the Gulf of Mexico, south of the state of Mississippi. In this area, there are many different salt structures present including salt canopies, diapirs, and salt pillows. The Callovian aged Louann Salt covers this area and is the cause of many of the salt structures and structures of the overlying formations seen in Gulf of Mexico today. Salt is mobile when subjected to stress from overlying sediment and gravity. Stress will force the salt to not only move upward, but to also move down slope deeper into adjacent basins through the …

Rural School District Strategies To Increase College, Career, And Military Readiness, Amelia J. Reeves

Electronic Theses and Dissertations

Preparing students for life after high school is a challenge faced by all K-12 educators. In small, rural school districts, school leaders encounter unique barriers and limitations due to the limited capacity of school counselors, geographic isolation, lack of resources, and other factors. The purpose of this qualitative, multiple case study was to explore the district-wide strategies utilized by rural school districts in West Central Texas to increase the career, college and military readiness (CCMR) of all students. Five cases were identified that met the criteria, which included being a rural district defined by TEA, a school administrator responsible for …