Physical Sciences and Mathematics Commons^™

Λcdm Cosmology + Chaotic Inflation, Peter A. Farago

Theses and Dissertations

ΛCDM cosmology is described in terms of general relativity and the Robertson-Walker metric. The evolution of the observable universe, currently dominated by dark energy (Λ) and cold dark matter (CDM), is presented in terms of its thermal history. CDM is extended to include an inflation epoch that accelerates the early expansion rate to near exponential levels. It is shown that inflation solves several problems in CDM and produces perturbations in the metric that lead to the observed anisotropies in the Cosmic Microwave Background and the formation of large scale cosmological structures. Various theories of inflation are explored. Predictions of inflation …

Diazaborole Linked Porous Polymers: Design, Synthesis, And Application To Gas Storage And Separation, Zafer Kahveci

Theses and Dissertations

The synthesis of highly porous organic polymers with predefined porosity has attracted considerable attention due to their potential in a wide range of applications. Porous organic polymers (POPs) offer novel properties such as permanent porosity, adjustable chemical nature, and noteworthy thermal and chemical stability. These remarkable properties of the POPs make them promising candidates for use in gas separation and storage. The emission of carbon dioxide (CO₂) from fossil fuel combustion is a major cause of global warming. Finding an efficient separation and/or storage material is essential for creating a cleaner environment. Therefore, the importance of the POPs …

Domination Numbers Of Semi-Strong Products Of Graphs, Stephen R. Cheney

Theses and Dissertations

This thesis examines the domination number of the semi-strong product of two graphs G and H where both G and H are simple and connected graphs. The product has an edge set that is the union of the edge set of the direct product of G and H together with the cardinality of V(H), copies of G. Unlike the other more common products (Cartesian, direct and strong), the semi-strong product is neither commutative nor associative.

The semi-strong product is not supermultiplicative, so it does not satisfy a Vizing like conjecture. It is also not submultiplicative so it shares these two …

Development Of Non-Traditional Platinum Anticancer Agents: Trans-Platinum Planar Amine Compounds And Polynuclear Platinum Compounds, Daniel E. Lee

Theses and Dissertations

Development of Non-Traditional Platinum Anticancer Agents: trans-Platinum Planar Amine Compounds and Polynuclear Platinum Compounds

By Daniel E. Lee, Ph.D.

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.

Virginia Commonwealth University, 2015

Major Director: Nicholas P Farrell, Ph.D., Professor, Department of Chemistry

Platinum anticancer compounds with cis geometry, similar to cisplatin, have been explored to circumvent the cisplatin resistance; however, they were not considered broadly active in cisplatin cells due to exhibiting similar or same cell death mechanism as cisplatin. Platinum compounds with trans geometry were less studied …

Coloring The Square Of Planar Graphs Without 4-Cycles Or 5-Cycles, Robert Jaeger

Theses and Dissertations

The famous Four Color Theorem states that any planar graph can be properly colored using at most four colors. However, if we want to properly color the square of a planar graph (or alternatively, color the graph using distinct colors on vertices at distance up to two from each other), we will always require at least \Delta + 1 colors, where \Delta is the maximum degree in the graph. For all \Delta, Wegner constructed planar graphs (even without 3-cycles) that require about \frac{3}{2} \Delta colors for such a coloring.

To prove a stronger upper bound, we consider only planar graphs …

Interdisciplinary Connections Between Science & Theatre, Jessica N. Dotson

Theses and Dissertations

Abstract

INTERDISCIPLINARY CONNECTIONS BETWEEN SCIENCE & THEATRE

Jessica Nicole Dotson

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Fine Arts at Virginia Commonwealth University.

Virginia Commonwealth University, 2015.

Major Director: Dr. Noreen C. Barnes, Director of Graduate Studies, Associate Professor of Theatre

In the 1990s, astronomer Peter Usher was searching for new ways to teach his introductory astronomy class at Pennsylvania State University. He began to engage his students by searching for astronomical connections from other disciplines. His focus was turned to the arts, especially the works of William Shakespeare. Usher found, while …

Analytical Method Development For The Detection And Analysis Of Protein Carbonyls, Chelsea M. Coffey

Theses and Dissertations

Oxidative stress can result in changes to many biomolecules and also affect their activities. We are interested in protein carbonylation, a type of unnatural oxidation which has been associated with numerous degenerative disease states and is also a consequence of the natural aging process. Protein carbonyls are stable species, but countless analytical barriers exist in terms of their identification. Thus, the main goal of this work was to develop and optimize analytical methods that could be used to help us better understand which, where, and how proteins are being carbonylated.

Initial studies involved method validation for carbonylating, tagging, and enriching …

Graph-Based Regularization In Machine Learning: Discovering Driver Modules In Biological Networks, Xi Gao

Theses and Dissertations

Curiosity of human nature drives us to explore the origins of what makes each of us different. From ancient legends and mythology, Mendel's law, Punnett square to modern genetic research, we carry on this old but eternal question. Thanks to technological revolution, today's scientists try to answer this question using easily measurable gene expression and other profiling data. However, the exploration can easily get lost in the data of growing volume, dimension, noise and complexity. This dissertation is aimed at developing new machine learning methods that take data from different classes as input, augment them with knowledge of feature relationships, …

Spiking Neural Networks: Neuron Models, Plasticity, And Graph Applications, Shaun Donachy

Theses and Dissertations

Networks of spiking neurons can be used not only for brain modeling but also to solve graph problems. With the use of a computationally efficient Izhikevich neuron model combined with plasticity rules, the networks possess self-organizing characteristics. Two different time-based synaptic plasticity rules are used to adjust weights among nodes in a graph resulting in solutions to graph prob- lems such as finding the shortest path and clustering.

Speed And Resolution In The Age Of Technological Reproducibility, Shawn Taylor

Theses and Dissertations

The rate of acceleration of the biologic and synthetic world has for a while now, been in the process of exponentially speeding up, maxing out servers and landfills, merging with each other, destroying each other. The last prehistoric relics on Earth are absorbing the same oxygen, carbon dioxide and electronic waves in our biosphere as us. A degraded .jpeg enlarged to full screen on a Samsung 4K UHD HU8550 Series Smart TV - 85” Class (84.5” diag.). Within this composite ecology, the ancient limestone of the grand canyon competes with the iMax movie of itself, the production of Mac pros, …

An Applied Mathematics Approach To Modeling Inflammation: Hematopoietic Bone Marrow Stem Cells, Systemic Estrogen And Wound Healing And Gas Exchange In The Lungs And Body, Racheal L. Cooper

Theses and Dissertations

Mathematical models apply to a multitude physiological processes and are used to make predictions and analyze outcomes of these processes. Specifically, in the medical field, a mathematical model uses a set of initial conditions that represents a physiological state as input and a set of parameter values are used to describe the interaction between variables being modeled. These models are used to analyze possible outcomes, and assist physicians in choosing the most appropriate treatment options for a particular situation. We aim to use mathematical modeling to analyze the dynamics of processes involved in the inflammatory process.

First, we create a …

Gas-Phase Reactions And Mechanistic Details Of Gold, Silver, And Iridium Complexes, Christopher Swift

Theses and Dissertations

The ever increasing demand for more efficient and environmentally benign routes for synthesizing target compounds, has led to the use of organometallic catalysts. This demand has created the need to understand the mechanistic details that are at work in these organometallic catalytic cycles. Along with this, there is a demand for new organometallic catalysts that are tailored for specific transformations. This presents a myriad of challenges for organometallic chemists. Unfortunately, it is often difficult to gain an understanding of the reaction mechanisms at work when the intermediates are too short lived to be observed in the condensed phase. It is …

Quartz Crystal Microbalance Studies On Friction Modifiers For Lubricant Applications, Carey Lehner

Theses and Dissertations

Lubricants are used in numerous applications to control friction and protect moving parts from fatigue. These fluids consist of a variety of surface active chemistries competing for the surface to provide performance. In order to develop fluids that meet the ever-increasing requirements (from legislation and manufacturers), techniques that can provide insight into surface adsorption, in real time, and relate it back to performance are critical.

The objective of this work is to determine if Quartz Crystal Microbalance with Dissipation (QCM-D) is an effective technique to investigate surfactant adsorption in regimes that are common to the transportation lubricant industry. QCM-D is …

Discrete Nonlinear Planar Systems And Applications To Biological Population Models, Shushan Lazaryan, Nika Lazaryan, Nika Lazaryan

Theses and Dissertations

We study planar systems of difference equations and applications to biological models of species populations. Central to the analysis of this study is the idea of folding - the method of transforming systems of difference equations into higher order scalar difference equations. Two classes of second order equations are studied: quadratic fractional and exponential.

We investigate the boundedness and persistence of solutions, the global stability of the positive fixed point and the occurrence of periodic solutions of the quadratic rational equations. These results are applied to a class of linear/rational systems that can be transformed into a quadratic fractional equation …

Electronic Principles Governing The Stability And Reactivity Of Ligated Metal And Silicon Encapsulated Transition Metal Clusters, Marissa B. Abreu

Theses and Dissertations

A thorough understanding of the underlying electronic principles guiding the stability and reactivity of clusters has direct implications for the identification of stable clusters for incorporation into clusters-assembled materials with tunable properties. This work explores the electronic principles governing the stability and reactivity of two types of clusters: ligated metal clusters and silicon encapsulated transition metal clusters. In the first case, the reactivity of iodine-protected aluminum clusters, Al₁₃I_x^- (x=0-4) and Al₁₄I_y^- (y-0-5), with the protic species methanol was studied. The symmetrical ground states of Al₁₃I_x^- showed no reactivity …

A Convergent Approach To The Continuous Synthesis Of Telmisartan Via A Suzuki Reaction Between Two Functionalized Benzimidazoles, Alex D. Martin

Theses and Dissertations

A direct and highly efficient synthesis has been developed for telmisartan, the active ingredient in the widely prescribed antihypertensive drug Micardis®. This approach brings together two functionalized benzimidazoles using a high-yielding Suzuki reaction that can be catalyzed by a homogeneous palladium source or palladium on a solid support.

The ability to perform the cross-coupling reaction was facilitated by the regio-controlled preparation of a 2-bromo-1-methylbenzimidazole precursor. The method developed is the first reported selective bromination at the 2-position of a benzimidazole and produces the first major precursor in high yield (93%). The second precursor, potassium (4-methyl-2-propylbenzimidazol-6-yl) trifluoroborate, was prepared from commercially …

Femtosecond Laser Beam Propagation Through Corneal Tissue: Evaluation Of Therapeutic Laser-Stimulated Second And Third-Harmonic Generation, William R. Calhoun Iii

Theses and Dissertations

One of the most recent advancements in laser technology is the development of ultrashort pulsed femtosecond lasers (FSLs). FSLs are improving many fields due to their unique extreme precision, low energy and ablation characteristics. In the area of laser medicine, ophthalmic surgeries have seen very promising developments. Some of the most commonly performed surgical operations in the world, including laser-assisted in-situ keratomileusis (LASIK), lens replacement (cataract surgery), and keratoplasty (cornea transplant), now employ FSLs for their unique abilities that lead to improved clinical outcome and patient satisfaction.

The application of FSLs in medical therapeutics is a recent development, and although …

Synthesis Of Unnatural Amino Acids For Genetic Encoding By The Pyrrolysyl-Trna/Rna Synthetase System, William A. Knight

Theses and Dissertations

The complexity of all biomolecules in existence today can be attributed to the variation of the amino acid repertoire. In nature, 20 canonical amino acids are translated to form these biomolecules, however, many of these amino acids have revealed posttranslational modifications (i.e. acetylation, methylation) after incorporation. Amino acids that exhibit PTM are known for their involvement in cellular processes such as DNA repair and DNA replication; these PTMs are commonly found on histones within the chromatin complex. Utilization of in vivo site-specific incorporation has recently reported functionality of post-translationally modified amino acids.1 xii Here we report the synthesis and in …

Enhanced Nanopore Detection Via Diffusion Gradients And Optical Tweezers, Kyle T. Brady

Theses and Dissertations

Nanopore-based resistive pulse sensing represents an important class of single-molecule measurements. It provides information about many molecules of interest (i.e. DNA, proteins, peptides, clusters, polymers, etc.) without the need for labeling. Two experiments that are especially well suited for studying with nanopore sensors are DNA sequencing and DNA-protein force measurements. This thesis will describe progress that has been made in both areas.

DNA sequencing has become an active area of research for stochastic single-molecule sensing, with many researchers striving for the ultimate goal of single-molecule de novo DNA sequencing. One intriguing method towards that goal involves the use of a …

Surface Photovoltage Transients For P-Type Algan, Karen L. Phumisithikul

Theses and Dissertations

There is an understanding of surface photovoltage (SPV) behavior for GaN, yet little is known about the SPV behavior for AlGaN. In this work, a Kelvin probe was used to measure the SPV for p-type AlGaN. Very slow SPV transients were found in AlGaN, which could not be explained with a simple thermionic model. A possible explanation of this behavior is the segregation of impurities to the surface, which causes significant reduction of the depletion region width (down to 2 nm), with carrier tunneling and hopping becoming the dominant mechanisms responsible for the SPV transients. To verify this assumption, …

On The Embeddings Of The Semi-Strong Product Graph, Eric B. Brooks

Theses and Dissertations

Over the years, a lot has been written about the three more common graph products (Cartesian product, Direct product and the Strong product), as all three of these are commutative products. This thesis investigates a non-commutative product graph, H, G, we call the Semi-Strong graph product, also referred in the literature as the Augmented Tensor and/or the Strong Tensor. We will start by discussing its basic properties and then focus on embeddings where the second factor, G, is a regular graph. We will use permutation voltage graphs and their graph coverings to compute the minimum genus for several families of …

Applications Of Stability Analysis To Nonlinear Discrete Dynamical Systems Modeling Interactions, Jonathan L. Hughes

Theses and Dissertations

Many of the phenomena studied in the natural and social sciences are governed by processes which are discrete and nonlinear in nature, while the most highly developed and commonly used mathematical models are linear and continuous. There are significant differences between the discrete and the continuous, the nonlinear and the linear cases, and the development of mathematical models which exhibit the discrete, nonlinear properties occurring in nature and society is critical to future scientific progress. This thesis presents the basic theory of discrete dynamical systems and stability analysis and explores several applications of this theory to nonlinear systems which model …

A Continuous Process Towards The Synthesis Of Quinolones, Stevara N. Clinton

Theses and Dissertations

Abstract

The development of quinolones is described from the first quinolone to the latest fluoroquinolones. Quinolones have generated considerable interest since their discovery because of their antibacterial capabilities. Analogs incorporating the 4-quinolone ring system comprise a largely expanding group of synthetic compounds. The development of antibacterial resistance has created the need for an efficient synthesis of quinolones that can be easily adapted toward the assembly of quinolone based antibacterial drugs.

There are several reported approaches to the 4-quinolone ring system. Many of these methods use expensive starting materials, require the removal of high boiling solvents, or use high temperature conditions …

Controlling For Confounding When Association Is Quantified By Area Under The Roc Curve, Hadiza I. Galadima

Theses and Dissertations

In the medical literature, there has been an increased interest in evaluating association between exposure and outcomes using nonrandomized observational studies. However, because assignments to exposure are not done randomly in observational studies, comparisons of outcomes between exposed and non-exposed subjects must account for the effect of confounders. Propensity score methods have been widely used to control for confounding, when estimating exposure effect. Previous studies have shown that conditioning on the propensity score results in biased estimation of odds ratio and hazard ratio. However, there is a lack of research into the performance of propensity score methods for estimating the …

Colloidal Synthesis And Optical Characterizations Of Semiconductor Nanocrystals From Nontoxic Elements, Minh Q. Ho

Theses and Dissertations

To date, the search efforts have shifted from the toxic II-VI, III-V and IV-VI semiconductors to more environmentally friendly materials. Among Group II-V semiconductors, Zn₃P₂ has shown to be a more benign option, similar to Group IV (Ge, Si) materials, for future applications in photovoltaics and optoelectronics. This work is dedicated to the development of wet-chemical synthetic routes of (1) Zn₃P₂ and (2) Group IV (Ge, Si, Si_1-xGe_x) nanocrystals with precise control over composition, crystal structure, size and dispersity by adjusting different reaction parameters such as temperature, time and solvent …

High-Throughput Data Analysis: Application To Micronuclei Frequency And T-Cell Receptor Sequencing, Mateusz Makowski

Theses and Dissertations

The advent of high-throughput sequencing has brought about the creation of an unprecedented amount of research data. Analytical methodology has not been able to keep pace with the plethora of data being produced. Two assays, ImmunoSEQ and the cytokinesisblock micronucleus (CBMN), that both produce count data and have few methods available to analyze them are considered.

ImmunoSEQ is a sequencing assay that measures the beta T-cell receptor (TCR) repertoire. The ImmunoSEQ assay was used to describe the TCR repertoires of patients that have undergone hematopoietic stem cell transplantation (HSCT). Several different methods for spectratype analysis were extended to the TCR …

A Comparison Of Obesity Interventions Using Energy Balance Models, Marcella Torres

Theses and Dissertations

An energy balance model of human metabolism developed by Hall et al. is extended to compare body composition outcomes among standard and proposed obesity interventions. Standard interventions include a drastic diet or a drastic diet with endurance training. Outcomes for these interventions are typically poor in clinical studies. Proposed interventions include a gradual diet and the addition of resistance training to preserve lean mass and metabolic rate. We see that resistance training, regardless of dietary strategy, achieves these goals. Finally, we observe that the optimal obesity intervention for continued maintenance of a healthy body composition following a diet includes a …

Considerations For Screening Designs And Follow-Up Experimentation, Robert D. Leonard

Theses and Dissertations

The success of screening experiments hinges on the effect sparsity assumption, which states that only a few of the factorial effects of interest actually have an impact on the system being investigated. The development of a screening methodology to harness this assumption requires careful consideration of the strengths and weaknesses of a proposed experimental design in addition to the ability of an analysis procedure to properly detect the major influences on the response. However, for the most part, screening designs and their complementing analysis procedures have been proposed separately in the literature without clear consideration of their ability to perform …

Proof-Of-Concept Of Environmental Dna Tools For Atlantic Sturgeon Management, Jameson Hinkle

Theses and Dissertations

Abstract

The Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus, Mitchell) is an anadromous species that spawns in tidal freshwater rivers from Canada to Florida. Overfishing, river sedimentation and alteration of the river bottom have decreased Atlantic Sturgeon populations, and NOAA lists the species as endangered. Ecologists sometimes find it difficult to locate individuals of a species that is rare, endangered or invasive. The need for methods less invasive that can create more resolution of cryptic species presence is necessary. Environmental DNA (eDNA) is a non-invasive means of detecting rare, endangered, or invasive species by isolating nuclear or mitochondrial DNA (mtDNA) from the …

Long-Term Effects Of Land Cover Change On Fish Assemblage Structure In The Piedmont And Coastal Plain Regions Of Virginia, Samuel F. Stickley

Theses and Dissertations

Changes in land cover and fish assemblage structure were assessed across two spatial and temporal scales in the Piedmont and Coastal Plain regions of the Chesapeake Bay watershed in Virginia. A long-term, local study (1953 to 2014) on the Tuckahoe Creek watershed used digitized aerial photography and satellite images (Landsat 5 TM and Landsat 8 OLI/TIRS) to quantify land cover change for five nested catchments in 1953, 1990, and 2014. Instream fish collections from 1958, 1990, and 2014 were utilized to assess a variety of fish assemblage metrics for each of the five catchments, and analyses were performed to assess …