Digital Commons Network^™

Detection Of Biomolecules Via Ocp Measurements Using Npg Electrodes, Borkat Ullah

Theses and Dissertations

In sensing application nanoporous gold (NPG) has attracted much attention. NPG is prepared by dealloying Au:Ag alloys. Characterization was done using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). In this work, the open circuit potential (OCP) of ferricyanide, cysteine, uric acid, and ascorbic acid was measured in phosphate buffer solution (PBS) and biofouling solution containing bovine serum albumin (BSA) at pH 7.4. OCP measurement has been hindered due to biofouling and surface passivation on the metal electrodes. By the use of the NPG electrodes, electrochemical activity can be maintained. From the OCP measurement of cysteine, …

Investigation Into The Reaction Profile Of A Bioinspired Nickel Complex, Denver Heitger

Theses and Dissertations

Metal complexes that can activate natural oxidants like H₂O₂ and O₂ have become a key research topic in many labs in hope of mimicking nature, by generating a bioinspired complex that can perform unique chemistry through green processes. To prepare the perfect catalyst, this has lead scientists to explore numerous avenues, including the use of both natural and artificial oxidants, to tease apart the reaction pathway taking place. A ligand system dear to the Lucas Lab (13-DOB) has been metalated with nickel, a cheap and earth abundant transition metal. Our bioinspired metal-(di)oxygen adducts can be formed …

Comparing Coastal Storm Impact To Decadal Change In Barrier Island Ecosystems, Philip A. Tuley

Theses and Dissertations

Highly dynamic coastal systems respond to disturbance events with a combination of topographic and vegetative changes. Sea level rise impacts on barrier islands have been quantified, but storm effects on vegetation are limited. Here we quantified barrier island vegetation change in response to an isolated storm event and compared to long-term periods. We hypothesized that disturbance-resisting areas with high woody vegetation cover and/or high foredune elevation would experience minimal transitions after a storm event, whereas disturbance-reinforcing areas with low vegetation cover and low foredune elevation would experience greater transitions between ecosystem states after a storm event. Patterns of dissonance were …

Synthesis And The Genetic Encoding Of Novel Lysine Post-Translational Modifications, Sahan A. Galbada Liyanage

Theses and Dissertations

Post-translational modifications (PTMs) play a significant role in regulating cell signaling and regulating the inner cellular environment. The study of PTMs and their primary biological functions is critical for the development of new medicines targeting the pathways and biomolecules responsible for the PTMs.

Previous studies revealed the direct coupling of the β -hydroxybutyryl lysine (K_BHB) modification with the gene expression. K_BHB in histone proteins links metabolism to epigenetics and gene expression and enables to study in-depth, how cell metabolism controls the gene expression and vice versa. Similar novel histone modification, K_Lac, attracts a special interest …

Probing Vibrational Wave Packets In Organophoshorous Molecules Using Femtosecond Time-Resolved Mass Spectrometry (Ftrms), Derrick Ampadu Boateng

Theses and Dissertations

The study of organophosphorus and nitroaromatic compounds is essential due to their suitability as models for understanding the dynamics of radiation induce damage to DNA sugar-phosphate backbone, and the detection of chemical warfare agents as well as nitroaromatic explosives (such as TNT). The ultrafast dynamics of these polyatomic radicals were studied using femtosecond time-resolved mass spectrometry (FTRMS), a versatile method that is capable of monitoring the ultrafast dynamics of rapid dissociation in the gas phase after the removal of an electron. The method uses a technique called pump-probe, which makes use of two time-delayed laser pulses. In this work, the …

Quantification And Modeling Of Bladder Biomechanics Mechanisms Linking Spontaneous Rhythmic Contractions And Dynamic Elasticity To Detrusor Overactivity, Zachary E. Cullingsworth

Theses and Dissertations

Overactive bladder (OAB) is a chronic condition affecting approximately 20% of adults in the United States. Detrusor overactivity (DO) is the presence of non-voiding contractions in the detrusor (bladder) muscle during filling and is present in some individuals with OAB. DO is currently identified visually during a urodynamics (UD) study involving pressure catheters and filling and voiding of the bladder to evaluate function. UD provides limited subtyping of DO, and an incomplete understanding of mechanisms contributing to OAB.

Aim 1 of this study was to develop objective tools to quantify, subgroup and better understand …

Utilizing Design Structure For Improving Design Selection And Analysis, Ahlam Ali Alzharani

Theses and Dissertations

Recent work has shown that the structure for design plays a role in the simplicity or complexity of data analysis. To increase the knowledge of research in these areas, this dissertation aims to utilize design structure for improving design selection and analysis. In this regard, minimal dependent sets and block diagonal structure are both important concepts that are relevant to the orthogonality of the columns of a design. We are interested in finding ways to improve the data analysis especially for active effect detection by utilizing minimal dependent sets and block diagonal structure for design.

We introduce a new classification …

Pseudo-Data Generation For Improving Clinical Named Entity Recognition, Jeffrey T. Smith

Theses and Dissertations

One of the primary challenges for clinical Named Entity Recognition (NER) is the availability of annotated training data. Technical and legal hurdles prevent the creation and release of corpora related to electronic health records (EHRs). In this work, we look at the imapct of pseudo-data generation on clinical NER using gazetteering and thresholding utilizing a neural network model. We report that gazetteers can result in the inclusion of proper terms with the exclusion of determiners and pronouns in preceding and middle positions. Gazetteers that had higher numbers of terms inclusive to the original dataset had a higher impact. We also …

Towards A Greener Route To Blockbuster Statin Drugs: Harnessing The Power Of Biocatalysis And Integrating Cross-Coupling Catalysis In The Synthesis Of Rosuvastatin, Chanaka M. Amarasekarage

Theses and Dissertations

As global and political awareness about green and sustainable practices sharpens in the face of dramatic climate change and environmentally detrimental practices, one attractive approach is to harness the catalytic potential of enzymes. Thus influenced, our efforts focused on the development of an innovative chemoenzymatic route to widely prescribed Blockbuster statin drugs, specifically rosuvastatin. In this work, we engineered novel deoxyribose phosphate aldolase (DERA) variants via rationally designed site-directed mutagenesis to accept non-natural, less polar substrate, acrolein, along with acetaldehyde. Several of new mutants displayed elevated tolerance towards aldehydes and showed effective incorporation of acrolein into the unprecedented enzymatically-derived chiral …

Optical Spectroscopy And Theoretical Modelling Of Carrier Dynamics In Group-Iv Alloy Quantum Dots, Rahnuma Rahman

Theses and Dissertations

In recent years, Ge_1−xSn_x alloy quantum dots (QDs) have attracted significant interest due to their potential applications in photodetectors and light emitting devices in visible to mid IR spectral range and compatibility with silicon based platforms. While bulk Ge is an indirect bandgap semiconductor (0.66 eV), direct transitions can be made possible by incorporation of α-Sn at concentrations of ~10%, which however lowers the bandgap. Utilizing quantum confinement by reducing the size to below the Bohr radius also promotes direct transitions and more importantly increases the fundamental transition energies in GeSn alloy QDs, making them suitable for …

Solid Phase Extraction And High-Precision Mass Spectrometry Analysis Methods For Crassostrea Virginica Metabolome, Alyssa Darling

Theses and Dissertations

Metabolomics is the rapidly-growing field which focuses on the endpoints of biological processes, and has the capability to provide a snapshot of an organisms’ interaction with their environment on a molecular scale. The objective of the experiment herein was to develop a standard metabolic extraction technique coupled with ultrahigh-precision analytical tools to build a global metabolic pathway of the keystone species Crassostrea virginica. To achieve this, C. virginica whole-body samples were extracted using acetonitrile and methanol, then split into a dehydrated group and a diluted group. Following reversed-phase solid phase extraction (RP-SPE) of both groups, metabolites were identified using …

Electric Field Control Of Fixed Magnetic Skyrmions For Energy Efficient Nanomagnetic Memory, Dhritiman Bhattacharya

Theses and Dissertations

To meet the ever-growing demand of faster and smaller computers, increasing number of transistors are needed in the same chip area. Unfortunately, Silicon based transistors have almost reached their miniaturization limits mainly due to excessive heat generation. Nanomagnetic devices are one of the most promising alternatives of CMOS. In nanomagnetic devices, electron spin, instead of charge, is the information carrier. Hence, these devices are non-volatile: information can be stored in these devices without needing any external power which could enable computing architectures beyond traditional von-Neumann computing. Additionally, these devices are also expected to be more energy efficient than CMOS devices …

Sound Propagation In Viscous Flows Using Piezoelectric Sensors And Non-Destructive Propagation Techniques And Its Applications, Ahmed M. Abdulkareem

Theses and Dissertations

Structural non-destructive evaluation techniques are applied to viscous flows to detect fluid property changes. The main operating principle consists of an actuator which provides a stimulus, and a sensor to receive a signal traveling to a fluid domain. The main challenge of the operating principle consists of investigating waves traveling in a viscous flow. Traveling waves utilizing a piezoelectric actuator-sensor pair are modeled and the results are validated experimentally. ANSYS models, coupled with a two-way fluid-solid interaction model, are built to investigate how far a signal travels and what frequency ranges are of interest. The numerical model includes modeling three …

Zero-Inflated Longitudinal Mixture Model For Stochastic Radiographic Lung Compositional Change Following Radiotherapy Of Lung Cancer, Viviana A. Rodríguez Romero

Theses and Dissertations

Compositional data (CD) is mostly analyzed as relative data, using ratios of components, and log-ratio transformations to be able to use known multivariable statistical methods. Therefore, CD where some components equal zero represent a problem. Furthermore, when the data is measured longitudinally, observations are spatially related and appear to come from a mixture population, the analysis becomes highly complex. For this matter, a two-part model was proposed to deal with structural zeros in longitudinal CD using a mixed-effects model. Furthermore, the model has been extended to the case where the non-zero components of the vector might a two component mixture …

Accounting For The Uncertainty Due To Chemicals Below The Detection Limit In Mixture Analysis, Paul M. Hargarten

Theses and Dissertations

Humans are exposed to multiple chemicals every day. Epidemiological studies have shown that chemical mixtures are associated with cancers, allergies, neurodevelopmental disorders, and other adverse health effects. To assess these associations, investigators are increasingly using chemical mixture approaches like weighted quantile sum (WQS) regression. In these studies, the research objectives are to determine whether a mixture of correlated chemicals is associated with an adverse health outcome and to identify the important chemicals. However, as experimental equipment measures each exposure to a chemical-specific detection limit, the exposures are unknown between zero and the detection limit. Indeed, the number of exposures below …

A Density Functional Theory Study Of Palladium Nanoparticles And Their Redox Properties On Graphene, Billie A. Radcliffe

Theses and Dissertations

Nanoparticles exhibit characteristics that are different from bulk materials as well as from atoms resulting in their application in numerous fields of applied material science. In particular, small palladium nanoparticles supported on graphene have been found to be outstanding catalysts for the Suzuki cross-coupling reaction. One explanation as to why these supported nanoparticles are such outstanding catalysts is because they may act as both electron donors and acceptors. Charge donating ligands are known to lower the ionization energy of clusters, making the clusters better donors. In this project, it is hypothesized that graphene supports may also act like charge donating …

Verification Of The Vertical Bubble Flow Experiments, Reginald Jones Ii

Theses and Dissertations

Detailed experimental design to support basic pedagogy of flow regimes – single phase liquid, bubbly, slug, annular, dispersed droplet, and single phase vapor – occurring in flow channels of nuclear reactors has been developed for EGMN 203 - Nuclear Engineering Practicum offering at Virginia Commonwealth University’s Department of Mechanical and Nuclear Engineering. The laboratory instruction will be used to help students forming ideas and understanding flow regimes occurring in nuclear engineering applications. We designed and constructed four water columns to act as surrogates for water channels in a nuclear reactor. Each column was used for a different experiment: salted versus …

Who Deserves To Be In Stem? How Threat And Confirmation Of The Gender Hierarchy Impact Helping Behavior Towards Prospective Stem Majors, Samantha A. Gnall

College of Graduate Studies: Theses & Dissertations

Current events that either threaten or confirm the current gender hierarchy may impact people differently. This can depend upon one’s group membership and their attitudes towards a fair and just society. When people are asked to help others while facing uncertainty of the hierarchy, they may choose to help or lash out in an effort to re-establish the hierarchy or dismantle the hierarchy. STEM faculty were presented with information that either did not threaten the gender hierarchy (i.e., maintaining gender inequality) or that threatened the current gender hierarchy (i.e., reaching gender equality). Participants were then given an opportunity to offer …

Prediction Of The Compressive Strength And Dynamic Modulus Of Fiber Reinforced Concrete By Ultrasonic Pulse Velocity Measurement At Early Ages, Daniel A. Castillo Pereira

College of Graduate Studies: Theses & Dissertations

This research investigates the relationship between early age ultrasonic pulse velocity and the compressive strength and dynamic modulus of steel, polypropylene, nylon, and glass fiber reinforced concrete. Previous studies prove that adding fibers to concrete alters the propagation of ultrasonic pulse velocity waves. Therefore, each type of fiber-reinforced concrete will have a unique relationship between ultrasonic pulse velocity and its compressive strength and dynamic modulus depending on fiber type, fiber volume fraction, water to cement ratio, and test age. To test this hypothesis, an experimental program comprising of one hundred eighty-nine 100 mm x 200 mm fiber reinforced concrete cylinders …

Does Dual Enrollment Impact Ctae, Robert J. Dollar

College of Graduate Studies: Theses & Dissertations

The purpose of this study was examine if legislation that greatly impacted the number of students taking dual enrollment courses in the state of Georgia was having an impact of CTAE programs in seven, rural school districts in southeast Georgia. This study employed a mixed methods research design. Quantitative data supplied by the Georgia Department of Education regarding enrollment numbers, as well as qualitative data gathered by the utilization of an open-ended questionnaire, were analyzed conjunctly to ascertain if an impact existed. This study focused on four overarching research questions regarding any potential impacts experienced with the implementation of the …

Analysis On Sharp And Smooth Interface, Elizabeth V. Hawkins

College of Graduate Studies: Theses & Dissertations

In biology, minimizing a free energy functional gives an equilibrium shape that is the most stable in nature. The formulation of these functionals can vary in many ways, in particular they can have either a smooth or sharp interface. Minimizing a functional can be done through variational calculus or can be proved to exist using various analysis techniques. The functionals investigated here have a smooth and sharp interface and are analyzed using analysis and variational calculus respectively. From the former we find the condition for extremum and its second variation. The second variation is commonly used to analyze stability of …

Explicit Pseudo-Kähler Metrics On Flag Manifolds, Thomas A. Mason Iii

College of Graduate Studies: Theses & Dissertations

The coadjoint orbits of compact Lie groups each carry a canonical (positive definite) Kähler structure, famously used to realize the group's irreducible representations in holomorphic sections of certain line bundles (Borel-Weil theorem). Less well-known are the (indefinite) invariant pseudo-Kähler structures they also admit, which can be used to realize the same representations in higher cohomology of the sections (Bott), and whose analogues in a non-compact setting lead to new representations (Kostant-Langlands). The purpose of this thesis is to give an explicit description of these metrics in the case of the unitary group G=U_n.

Physiological Response Of Elasmobrachs During Propofol Immersion, Matthew Levendosky

College of Graduate Studies: Theses & Dissertations

Sensory experiments require anesthesia so the animal is immobilized, however fish anesthetics have shown to depress sensory responses. Newer anesthetics may offer similar anesthetic relief, but differ in means of action so sensory responses may be unaffected. Propofol has been used intravenously on small elasmobranchs but may provide prolonged effects if used as an immersion anesthetic. Objectives of this study were 1. Determine appropriate concentration of anesthetic to minimize induction and recovery for animals anesthetized at a surgical plane of anesthesia and 2. Measure physiological response of the pupil to light stimuli during anesthetic immersion. To address these objectives, I …

The Relationship Between Servant Leadership And Teacher Retention And Student Achievement, David Earl Murphy

College of Graduate Studies: Theses & Dissertations

This non-experimental quantitative study aimed to determine if servant leadership influenced teacher retention or student achievement and if teacher retention influenced student achievement. This study’s respondents were 145 middle and high school teachers within a contiguous rural region of the Southeastern United States. Survey responses were received and analyzed during the late summer of 2020. Three research questions guided this study: Does servant leadership [high, low] influence teacher retention intention; What is the effect of servant leadership [high, low] on student achievement by categorical population groups as identified by the GaDOE; and lastly, What is the effect of teacher retention …

The Impact Of An Intensive Blended Learning Reading Intervention On Standardized Assessment Scores, Ashley M. Snyder

College of Graduate Studies: Theses & Dissertations

The current study documents the effects of the Language! Live intensive, blended learning reading intervention on the Georgia Milestones Assessment Lexile Scores. The purpose of the study was to determine the impact of an intensive blended learning reading intervention on the standardized assessment scores of middle school students who were at least two grade levels behind in reading at a Title I school in Georgia and aimed to establish if students who were significantly below grade level could make growth with the assistance of an intensive blended learning reading intervention. The study included the data of 133 students in two …

Association Rules Patterns Discovery From Mixed Data, Welendawa Acharige Charith A. Elson

College of Graduate Studies: Theses & Dissertations

Finding Association Rules has been a popular unsupervised learning technique for dis covering interesting patterns in commercial data for well over two decades. The method seeks groups of data attributes and their values where their probability density of these attributesattherespectivevaluesismaximized. Therearecurrentlywell-establishedmeth ods for tackling this problem for data with categorical (discrete) attributes. However, for the cases of data with continuous variables, the techniques are largely focusing on cate gorizing continuous variables into intervals of interest and then relying on the categorical data methods to address the problem. We address the problem of finding association rules patterns in mixed data by …

A Numerical And Experimental Study On Effect Of Composition Of Ar-N2 Shielding Gas On The Weld Bead Profile And Its Prediction For Hot Wire Arc Additive Manufacturing, Niraj Pudasaini

College of Graduate Studies: Theses & Dissertations

Wire arc additive manufacturing is a process of making three-dimensional metal parts in a layer-by-layer approach using a feed wire and electric arc as a heat source. Wire arc additive manufacturing (WAAM) is becoming more popular due to its ability to create complex 3D parts, less build time, high deposition rate, and significant cost savings. Out of the many parameters used in WAAM, one of the important parameters is shielding gas which plays a significant role in material quality, properties, and defects. In this study, a controlled amount of Argon (Ar) and Nitrogen (N₂) shielding gases are used …

Can Farmers And Bats Co-Exist? Farmer Attitudes, Knowledge, And Experiences With Bats In Belize, Hannah G. Shapiro, Adam S. Willcox, Mallory Tate, Emma V. Willcox

Human–Wildlife Interactions

Bats (Chiroptera) are often viewed negatively by the public. Negative public perceptions of bats may hinder efforts to conserve declining populations. In Belize, the presence of vampire bats (Desmodus rotundus and Diphylla ecaudata) exacerbates the potential for conflicts with humans because of the increased rabies transmission risks. To mitigate these risks, the Belize government provides farmers with assistance to trap and remove vampire bats. In June 2018, we surveyed farmers (n = 44) in and adjacent to the Vaca Forest Reserve in Belize to learn more about their attitudes, knowledge, and experiences with bats. This information may …

Use Of Roadside Deer Removal To Reduce Deer–Vehicle Collisions, John C. Kilgo, John I. Blake, Tracy E. Grazia, Andy Horcher, Michael Larsen, Thomas Mims, Stanley J. Zarnoch

Human–Wildlife Interactions

Identification of management tools to reduce the incidence of deer–vehicle collisions (DVCs) is important to improve motorist safety. Sharpshooting to reduce white-tailed deer (Odocoileus virginianus; deer) along roads has proven successful in urban situations but has not been evaluated in undeveloped areas. We used a before-after-control-impact (BACI) design to evaluate the use of sharpshooting to reduce DVCs along roads on the uninhabited U.S. Department of Energy’s Savannah River Site, South Carolina, USA, during 2011–2017. We removed 242 deer from 4 treatment roads during 2015 and 2016, with 2-year removal rates per road averaging 5.0 deer/km of road (range …

Elements Of Safety Management System In The Construction Industry And Measuring Safety Performance – A Brief, Mostafa Elsebaei, Omar Elnawawy, Ayman Ahmed Ezzat Othman, Mohamed Badawy

Architectural Engineering

Construction industry is considered to be one of the most hazardous industries in the world. The reason could be attributed to its hazardous nature as it is an accident-prone industry. Thus, a need for better understanding of safety management system is essential for improving safety performance in this sector. This paper discusses briefly the elements of safety management by presenting different systems (such as Oregon OSHA Occupational Health and Safety Administration, and OTAR Overseas Territories Aviation Circle) and elaborating their elements. It also discusses two types of measuring safety performance the first is the lagging indicators and the second is …