Physical Sciences and Mathematics Commons^™

High Speed Atomic Force Microscope Design Using Dvd Optics, Thomas Carlson

Theses and Dissertations

We examine the design of a high speed atomic force microscope using an optical pickup from a commercially available compact disc/digital versatile disc drive. An investigation of the commercial optical pickup is done with the goal of determining how it can be used for dimensional measurements on nanometer scale. An evaluation of noise sources, imaging capabilities, and functionality is performed.

Spatial Scheduling Algorithms For Production Planning Problems, Sudharshana Srinivasan

Theses and Dissertations

Spatial resource allocation is an important consideration in shipbuilding and large-scale manufacturing industries. Spatial scheduling problems (SSP) involve the non-overlapping arrangement of jobs within a limited physical workspace such that some scheduling objective is optimized. Since jobs are heavy and occupy large areas, they cannot be moved once set up, requiring that the same contiguous units of space be assigned throughout the duration of their processing time. This adds an additional level of complexity to the general scheduling problem, due to which solving large instances of the problem becomes computationally intractable. The aim of this study is to gain a …

Investigating Mechanical Properties Of Metallic Nanowires Using Molecular Dynamics, Alex Khammang

Theses and Dissertations

Metallic nanowires have useful applications in scanning tunneling microscopes and atomic force microscopes due to their unique sensitivity to force and electricity. These unique properties arise because of the large surface area to volume ratio. One of these properties is that introducing twinning planes the mechanical properties of metallic nanowires can be altered. The effects of twinning planes on metallic nanowires were studied using molecular dynamics simulations. Silver, copper, and nickel nanowires with and without twinning planes were simulated with engineering strain until the first yielding stress was obtained. The radial simulations showed that as the radius of twinned nanowires …

Stochastic Differential Equations And Numerical Applications, Matthew Rajotte

Theses and Dissertations

We will explore the topic of stochastic differential equations (SDEs) first by developing a foundation in probability theory and It\^o calculus. Formulas are then derived to simulate these equations analytically as well as numerically. These formulas are then applied to a basic population model as well as a logistic model and the various methods are compared. Finally, we will study a model for low dose anthrax exposure which currently implements a stochastic probabilistic uptake in a deterministic differential equation, and analyze how replacing the probablistic uptake with an SDE alters the dynamics.

Aromaticity Rules In The Development Of Negative Ions, Brandon Child

Theses and Dissertations

Organic molecules are known for their stability due to aromaticity. Superhalogens, on the other hand, are highly reactive anions, whose electron affinity is larger than that of chlorine. This thesis, using first principles calculations, explores possible methods for creation of superhalogen aromatic molecules while attempting to also develop a fundamental understanding of the physical properties behind their creation. The first method studied uses anionic cyclopentadienyl and enhances its electron affinity through ligand substitution or ring annulation in combination with core substitutions. The second method studies the possibilities of using benzene, which has a negative electron affinity (EA), as a core …

Investigation Of The 4-Amino-Α,Α-Dihydroxy-3,5-Dichloroacetophenone Impurity In The Synthesis Of Clenbuterol Hydrochloride, Kerry Moore

Theses and Dissertations

Clenbuterol Hydrochloride is a bronchodilator marketed as Spirospent® for Human Pharmaceuticals and as Ventipulmin® for Veterinary Pharmaceuticals by Boehringer Ingelheim.1 This research investigates formation of the 4-amino-α,α-dihydroxy-3,5-dichloroacetophenone impurity (Dihydroxy Impurity) in the synthesis of Clenbuterol Hydrochloride. The Dihydroxy Impurity has increased three-fold since the process was transferred to Boehringer Ingelheim Chemicals, Inc. in 1999.1 The Dihydroxy Impurity is proposed to be produced during an amination/reduction step from a reaction of water with the starting material.2 Additionally, the Dihydroxy Impurity can be formed by the reaction of water with an impurity, 4-amino-α,α-didibromo-3,5-dichloroacetophenone (Dibromo Impurity), that is generated in the previous step.2 …

Characterizing Cancellation Graphs, Cristina Mullican

Theses and Dissertations

A cancellation graph G is one for which given any graph C, we have G\times C\cong X\times C implies G\cong X. In this thesis, we characterize all bipartite cancellation graphs. In addition, we characterize all solutions X to G\times C\cong X\times C for bipartite G. A characterization of non-bipartite cancellation graphs is yet to be found. We present some examples of solutions X to G\times C\cong X\times C for non-bipartite G, an example of a non-bipartite cancellation graph, and a conjecture regarding non-bipartite cancellation graphs.

Application And Extension Of Weighted Quantile Sum Regression For The Development Of A Clinical Risk Prediction Tool, Ghalib Bello

Theses and Dissertations

In clinical settings, the diagnosis of medical conditions is often aided by measurement of various serum biomarkers through the use of laboratory tests. These biomarkers provide information about different aspects of a patient’s health and the overall function of different organs. In this dissertation, we develop and validate a weighted composite index that aggregates the information from a variety of health biomarkers covering multiple organ systems. The index can be used for predicting all-cause mortality and could also be used as a holistic measure of overall physiological health status. We refer to it as the Health Status Metric (HSM). Validation …

A Study Of The Relationship Between Childhood Body Size And Adult Blood Pressure, Cardiovascular Structure And Function, Yangyang Deng

Theses and Dissertations

BACKGROUND: Little is known of the effects of obesity, body size and body composition, and blood pressure (BP) in childhood on hypertension (HBP) and cardiac structure and function in adulthood due to the lack of long-term serial data on these parameters from childhood into adulthood. In the present study, we are poised to analyze these serial data from the Fels Longitudinal Study (FLS) to evaluate the extent to which body size during childhood determines HBP and cardiac structure and function in the same individuals in adulthood through mathematical modeling. METHODS: The data were from 412 males and 403 females in …

A Study On Investment Strategies For Retirement Planning, Megha Goel

Theses and Dissertations

The aim of the thesis is to construct an effective realistic retirement income plan for an individual investor. We propose realistic frameworks with specific inputs given by investor such as number of investment instruments, income, and length of the time period before retirement using Modern Portfolio theory. The aim is to develop a retirement framework using fundamentals of Modern Portfolio Theory as per investor’s needs on asset allocation assuming investor’s risk appetite reduces as he ages in life and worries for real retirement income planning by comparing different statistical models scenarios. In each of the Scenarios we have 3 changing …

Determination Of The Factors That Affect The Gas-Phase Reactivity Of Metal-Centered Cyclopropanation Catalysts And Examination Of The Properties Of Their Reaction Products, Jamal Aldajaei

Theses and Dissertations

Gas phase studies of organometallic systems have provided deep insight into reaction mechanisms and reaction intermediates. In this thesis, several metal/ligand systems were examined in an effort to form metal carbenes in the gas phase. With cobalt and iron porphyrins, the carbene undergoes metal-ligand insertion. With copper bis-oxazolines, metal carbenes tend to undergo metal-ligand insertion and a Wolff rearrangement. To avoid insertions, we turned to a rigid ligand, 1, 10-phenanthroline. Under ESI conditions, a copper (I) complex with phenanthroline can be formed. When treated with diazoacetate esters, the dominant product results from addition with loss of nitrogen followed by loss …

Synthesis And Characterization Of Cobalt Carbide Based Nanomaterials, Zachary Huba

Theses and Dissertations

Permanent magnets are used heavily for multiple applications in industry and current electronic technologies. However, the current permanent landscape is muddled by high cost of materials and insufficient magnetic or thermal properties. The primary focus of this dissertation work is the synthesis and optimization of a new permanent magnetic material, in the form of cobalt carbide nanomaterials. The optimization revolved around controlling the crystal phase and particle shape of synthesized cobalt carbide particles; these parameters have significant impact on the observed magnetic properties of magnetic nanoparticles. Co₃C was identified to be the preferred crystal phase, leading to better …

Platinum Complexes And Zinc Finger Proteins: From Target Recognition To Fixation, Samantha Tsotsoros

Theses and Dissertations

Bioinorganic chemistry strives to understand the roles of metals in biological systems, whether in the form of naturally occurring or addition of non-essential metals to natural systems. Metal ions play vital roles in many cellular functions such as gene expression/regulation and DNA transcription and repair. The study of metal-protein-DNA/RNA interactions has been relatively unexplored. It is important to understand the role of metalloprotein interactions with DNA/RNA as this enhanced knowledge may lead to better understanding of diseases and therefore more effective treatments. A major milestone in the development of this field was the discovery of the cytotoxic properties of cisplatin …

Investigations Into The Fluorescent Covalent Labeling Of Biomolecules Utilizing Rhodamine Dyes, Electrophilic Leaving Groups And Mrna Display., Susan D. Selaya

Theses and Dissertations

The discovery of a method by which proteins of interest can selectively be labeled with a probe of choice intracellularly is a longstanding goal in chemical biology research. Conventional labeling techniques have utilized large domain tags but despite the development of small labeling molecules there have been no short peptide sequences known to covalently label a small molecule without the aid of an enzymatic process or metal chelation. We aimed to find a sequence of nucleophilic peptides that reacted covalently and specifically with electrophilic small labeling molecules using mRNA display. Our goal was to show that an electrophilic small labeling …

Exploring The Asymmetric Environment Of Various Chiral Catalysts Using A Modified Ion-Trap Mass Spectrometer: Towards The Development Of A Rapid Chiral Catalyst Screening Method, Cary M. Davis

Theses and Dissertations

Since the tragedy of the drug Thalidomide® in the late 1950 to early 1960’s, chirality has been recognized as an important aspect that must be controlled in the drug development process in the pharmaceutical industry. Since then, there has been a considerable movement towards single enantiomer drugs. This demand has presented many challenges for the synthetic organic chemist. Chiral catalysts offer one solution to this problem, as they afford the unique ability to preferentially synthesize one enantiomer. Unfortunately, the design of new chiral catalysts is often empirical, with luck and trial and error necessary due to factors that govern enantioselectivity. …

Magnetic Properties Of Hematite (Α-Fe2o3) Nanorods, Samar A. Ghopry

Theses and Dissertations

At this study three samples of hematite nanorods were deposited on the silicon substrates with different varieties of glancing angle deposition techniques. One sample (S1) was prepared by using thermal deposition with partially ionized beam (PIB) and substrate rotation. The second sample (S2) was synthesized by using thermal deposition with PIB and no substrate rotation. The third sample (S3) was obtained by using E-beam deposition, PIB and rotating substrate. In addition, one sample of magnetite nanorods (S4) has been prepared in order to compare the magnetic properties of the two different iron oxides. S4 was prepared by using thermal deposition …

Using Structural Analysis To Investigate The Function Of Suppressor Of Ikk-Epsilon (Sike), Sean W. Mckinley

Theses and Dissertations

The innate immune system provides the body’s first line of defense against pathogenic challenge through pathogen recognition and initiation of the immune response. Among the various cellular mechanisms of pathogen recognition in mammals, Toll-like receptor 3 (TLR3) recognizes viral dsRNA. Stimulation of TLR3 signaling pathway leads to transcription of pro-inflammatory cytokines and type-1 Interferons. Suppressor of IKKε (SIKE) interacts with two kinases in the signaling pathway, IKKε and TANK binding kinase 1 (TBK1), inhibiting the transcription of type I interferons. Recently, the Bell Laboratory discovered that SIKE blocks TBK1-mediated activation of type I interferons by acting as a high affinity, …

Characterization Of Individual Charged Au25(Sg)18 Clusters And Their Enhancement Of Single Molecule Mass Spectrometry, Christopher Angevine

Theses and Dissertations

Metallic quantum clusters are stable structures that can exhibit many useful magnetic, chemical, and optical properties. Developing clusters for specific applications requires accurate methods for characterizing their physical and chemical properties. Most cluster characterization methods are ensemble-based measurements that can only measure the average values of the cluster properties. Single cluster measurements improve upon this by yielding information about the distribution of cluster parameters. This investigation describes the initial results on a new approach to detecting and characterizing individual gold nanoclusters (Au25(SG)18) in an aqueous solution with nanopore-based resistive pulse sensing. We also present a new application where the clusters …

The Study Of Au(Iii) Compounds And Their Interaction With Zinc Finger Proteins, Sarah Spell

Theses and Dissertations

Gold compounds have been used in medicine dating back as early as 2500 BC. Over the years gold(I) and gold(III) compounds have been used and designed to target rheumatoid arthritis, cancer, and viral diseases. New drug targets have been found for gold compounds that give insight into their mechanisms of action. Here we focus on the synthesis of Au(III) compounds designed to selectively target zinc finger (ZF) proteins. ZF proteins exhibit a variety of functions, including transcription, DNA repair, and apoptosis. Displacement of the central zinc ion, along with mutation of coordinated amino acids can result in a loss of …

Discovering Spam On Twitter, Ioana-Alexandra Bara

Theses and Dissertations

Twitter generates the majority of its revenue from advertising. Third parties pay to have their products advertised on Twitter through: tweets, accounts and trends. However, spammers can use Sybil accounts (fake accounts) [21] to advertise and avoid paying for it. Sybil accounts are highly active on Twitter performing advertising campaigns to serve their clients [5]. They aggressively try to reach a large audience to maximize their influence. These accounts have similar behavior if controlled by the same master. Most of their spam tweets include a shortened URL to trick users into clicking on it. Also, since they share resources with …

Ramp Loss Svm With L1-Norm Regularizaion, Eric Hess

Theses and Dissertations

The Support Vector Machine (SVM) classification method has recently gained popularity due to the ease of implementing non-linear separating surfaces. SVM is an optimization problem with the two competing goals, minimizing misclassification on training data and maximizing a margin defined by the normal vector of a learned separating surface. We develop and implement new SVM models based on previously conceived SVM with L_1-Norm regularization with ramp loss error terms. The goal being a new SVM model that is both robust to outliers due to ramp loss, while also easy to implement in open source and off the shelf mathematical programming …

Light Mediated Drug Delivery Using Photocaged Molecules And Photoswitchable Peptides, Deboleena Mitra

Theses and Dissertations

There are many different types of targeted therapy for cancer treatment. The method of light mediated targeted therapy that we have developed uses photocaged molecules and photoswitchable peptides.

In photocaging, a biologically active molecule is made inactive by the attachment of a photocleavable blocking group. On exposure to UV radiation the photocleavable entity is removed and the biologically active molecule is released. Using this concept we have designed a prodrug that consists of a cell impermeable hydrophilic molecule attached to a photocaged doxorubicin. Upon irradiation with UV light the photosensitive group is removed and cytotoxic doxorubicin is released at the …

Mobile Indoor Positioning For Augmented Reality Systems, Robert B. Glass

Theses and Dissertations

This thesis explores the creation and setup of a prototype that allows users of the device to interact within an indoor real world environment and a virtual environment simultaneously using high-tech common technology. The prototype is comprised of a small mobile device such as a cellular mobile phone, Raspberry Pi computer, a battery powered handheld Pico projector, and software developed for the Android OS. The software can easily be ported to other mobile and non-mobile operating systems. The mobile device must contain accelerometer, magnetometer, and gyroscope embedded sensors as well as 802.11 wireless network chip. The prototype software implements an …

Global Assessment Of Radiocarbon Isotopic Analysis For Particulate And Dissolved Organic Carbon In Riverine Systems, Ashley Tucker

Theses and Dissertations

Rivers are a significant source of particulate and dissolved organic carbon (POC, DOC) into inland waters and coastal systems and provide a fundamental linkage between the terrestrial, oceanic, and atmospheric carbon reservoirs. Recent studies have examined the relationship between the quantity and form (POC vs. DOC) of carbon delivered to the aquatic system; however, little is known about the age of POC and DOC exported and how the radiocarbon age may vary with latitude, topographic gradient, vegetation, and land use. I provide the first global synthesis of published radiocarbon values of POC and DOC (∆14C). Inclusion of DOC and POC …

Latent Variable Models Given Incompletely Observed Surrogate Outcomes And Covariates, Chunfeng Ren

Theses and Dissertations

Latent variable models (LVMs) are commonly used in the scenario where the outcome of the main interest is an unobservable measure, associated with multiple observed surrogate outcomes, and affected by potential risk factors. This thesis develops an approach of efficient handling missing surrogate outcomes and covariates in two- and three-level latent variable models. However, corresponding statistical methodologies and computational software are lacking efficiently analyzing the LVMs given surrogate outcomes and covariates subject to missingness in the LVMs. We analyze the two-level LVMs for longitudinal data from the National Growth of Health Study where surrogate outcomes and covariates are subject to …

New Synthetic Strategies For Improved Gas Separation By Nanoporous Organic Polymers, Suha Altarawneh

Theses and Dissertations

Abstract NEW SYNTHETIC STRATEGIES FOR IMPROVED GAS SEPARATION BY NANOPOROUS ORGANIC POLYMERS Suha S. Altarawneh, Ph.D. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major cause of climate change. Therefore, the efficient separation of CO2 from mixtures of gases such as flue gas and impure sources of CH4 (e.g. natural gas and landfill gas) is an essential step in meeting the ever increasing demands on natural gas and creating a cleaner environment. Carbon capture and storage technology (CCS) is one of the methods employed for gas separation using chemisorption and/or physisorption processes. Several materials such as …

The Total Picture: Multiple Chemical Exposures To Pregnant Women In The Us – An Nhanes Study Of Data From 2003 Through 2010, Teri Cabana

Theses and Dissertations

INTRODUCTION: Chemical exposures to US pregnant women have been shown to have adverse health impacts on both mother and fetus. A prior paper revealed that US pregnant women in 2003-2004 had widespread exposure to multiple chemicals. The goal of this research is to examine how environmental chemical exposures to US pregnant women have changed from 2003 to 2010 and to look further at the extent of simultaneous exposure to multiple chemicals in US pregnant women using biomonitoring data available through NHANES (the National Health and Nutritional Examination Survey). METHODS: Using available NHANES data from the following cycles (2003-2004, 2005-2006, 2007-2008, …

Prospect Theory Preferences In Noncooperative Game Theory, Philip Leclerc

Theses and Dissertations

The present work seeks to incorporate a popular descriptive, empirically grounded model of human preference under risk, prospect theory, into the equilibrium theory of noncooperative games. Three primary, candidate definitions are systematically identified on the basis of classical characterizations of Nash Equilibrium; in addition, three equilibrium subtypes are defined for each primary definition, in order to enable modeling of players' reference points as exogenous and fixed, slowly and myopically adaptive, highly flexible and non-myopically adaptive. Each primary equilibrium concept was analyzed both theoretically and empirically; for the theoretical analyses, prospect theory, game theory, and computational complexity theory were all summoned …

Fabrication Of Nanoporous Gold And Biological Applications, Badharinadh Uppalapati

Theses and Dissertations

FABRICATION OF NANOPOROUS GOLD AND BIOLOGICAL APPLICATIONS By Badharinadh Uppalapati A Dissertation submitted in partial fulfillment of the requirements for the degree of Master of Science at Virginia Commonwealth University. Virginia Commonwealth University, 2014 Major Director: Maryanne M. Collinson, Professor, Department of Chemistry Fabrication of nanoporous gold electrodes by dealloying Au:Ag alloys has attracted much attention in sensing applications. In the first part of this work, the electrochemical response of the redox active molecule, potassium ferricyanide, in a solution of bovine serum albumin in buffer, serum or blood was studied using nanoporous gold and comparisons made to planar gold. Nanoporous …

Affinity Enrichment And Mass Spectrometric Quantitation Of Protein Carbonyls, Suresh Narayanasamy

Theses and Dissertations

The importance of the role of oxidative stress in aging and numerous age-related diseases has become undeniable due to enormous weight of supporting evidence from the field of free radical biology. One of the most prominent oxidative modifications of proteins is the introduction of carbonyl groups. As with oxidative stress, protein carbonylation has been correlated with various disease states and natural aging. While protein carbonyls are relatively stable, reproducible detection and modification site localization are still challenging. This thesis details attempts to improve the analytical methodology used for the identification and quantitation of carbonylated proteins. We have studied the impact …