Physical Sciences and Mathematics Commons^™

Studies Of Aspect Angle Dependence Of Plasma Turbulence At Haarp, Nargis Adham

Master's Theses and Doctoral Dissertations

We report the results from a recent series of campaigns employing the HAARP HF transmitter to generate and study strong Langmuir turbulence (SLT) in the interaction region of overdense ionospheric plasma. Diagnostics included the Modular UHF Ionospheric Radar (MUIR) sited at HAARP, the Super DARN-Kodiak HF radar, and HF receivers to record stimulated electromagnetic emissions (SEE). Short pulse, low duty cycle experiments demonstrate control and suppression of artificial field-aligned irregularities (AFAI). This allows the isolation of ponderomotive plasma turbulence effects. Plasma line spectra exhibit a marked dependence on the aspect angle of the HF pump beam and the pointing of …

A Comparative Analysis Of The Electronic And Structural Characteristics Of Polyphenolic Inhibitors Of Pai-1, Patrick Spoutz

Senior Honors Theses and Projects

Polyphenolic compounds containing two gallate groups have been shown to be effective inhibitors of Plasminogen Activator Inhibitor-1 (PAI-1). In this work we use Density Functional calculations to examine energetically-accessible configurations of two digallate compounds exhibiting disparate inhibitory activity toward PAI-1. In addition, we examine the partial charges of potentially acidic protons and the relative stability of the respective conjugate bases of a select group of PAI-1 inhibitors. This analysis was carried out to determine whether such characteristics can be used to distinguish between effective and less effective inhibitors. An examination of the stable configurations of CDE-008 and CDE-056 indicates that …

Computational Studies Of Stereochemical Effects In The Synthesis Of Sugar Mimics, Louis Anthony Lello

Senior Honors Theses and Projects

Density Functional methods are used to model the tandem aza-Cope rearrangement – Mannich cyclization reaction leading to substituted acylpyrrolidines. The ultimate goal is to determine optimum reaction conditions that maximize stereoselectivity, as only one set of stereoisomers is pharmacologically active. Three aspects of the reaction are investigated. First, we determine the relative size of three rotational barriers in the interconversion of two iminium cation stereoisomers that are precursors to the aza-Cope rearrangement. The lowest energy pathway for the interconversion is identified, as well as the relative stability of the two stereoisomers for two different substituents: diphenyl and methyl. Activation barriers …

Analysis Of The Effect Of Various Ligands On The Hydrolysis Of Ruthenium (Iii) Complexes And Interpretation Of Kinetics Of Hydrolysis Profiles By Uv-Visible Spectrophotometry, Sudheer Koneru

Master's Theses and Doctoral Dissertations

Cancer is one of the major causes of death in the world. Discovery of platinum metal-based drugs like cisplatin and carboplatin have proved to be successful in cancer treatment. Due to subsequent development of resistance, side effects, and fewer toxic effects of these drugs, the usage of these drugs has been limited. Novel drugs were being synthesized utilizing the transition metals like ruthenium, osmium, and copper.

In this research, ruthenium metal complexes of the formula HL[RuCl4L2] (where L= ligand) were synthesized. These ruthenium-based drugs exist in prodrug forms which are activated into antitumor drugs by means of hydrolysis, redox reactions, …

Influence Of Metal Nanoparticles On Fluorescence Properties, Vamsi K. Kandimalla

Master's Theses and Doctoral Dissertations

In this project, we studied the effect of silver and gold nanoparticles of various sizes on the fluorescence properties of tris (2, 2-bipyridyl) dichloro ruthenium (II) hexahydrate (Ru (bpy)3 2+), tryptophan and phenylalanine. For (Ru (bpy)3 2+) absorbed on silver and gold nanoparticles, the fluorescence intensity was quenched and showed a significant increase in the fluorescence lifetimes. These quenched intensities were due to energy transfer processes from the donor (Ru (bpy)3 2+) to the metal nanoparticles. Conversely, tryptophan showed enhanced fluorescence intensities with an increase in the size of the nanoparticles, which may be attributed to the effect of fluorescence …

Structure-Activity Relationships Of Pai-1 Inhibitors, Karen Sanders

Master's Theses and Doctoral Dissertations

The inhibition of plasminogen activator inhibitor-1 (PAI-1) is anticipated to increase our understanding of various human ailments with which high levels of PAI-1 have been associated, including diabetes, stroke, and atherosclerosis. Previous accounts have reported the synthesis of inhibitors that bind to PAI-1 with a low affinity, inhibit the serpin plasma protein antithrombin III, and/or fail to inhibit PAI-1 when vitronectin, a cofactor of PAI-1 is present. The synthesis of small-molecule inhibitors of PAI-1 that improve upon these properties has been the main goal of this research. Research efforts focused on examining changes in inhibitor potency based on the manipulation …

Ecological Method Development For Detecting N-Nitrosodimethylamine In Water Using Hplc-Pdad, Jolisa Mcday

Master's Theses and Doctoral Dissertations

Using ethanol, a sustainable reversed-phase high-performance liquid chromatographic method with photo-diode array detection (HPLC-PDAD) was investigated to detect sub-parts per billion concentrations of N-nitrosodimethylamine (NDMA) in drinking water and environmental water samples. This presents a practical and “green” option to analytical methods that require laborious derivatization, expensive detectors and unecological solvents.

Mobile phase characteristics, instrument operating parameters, and sample preparation were investigated. Selectivity for NDMA was evaluated using three different C18 columns. Optimal peak resolution and detection were achieved at 231 nm. The limit of detection and quantitation for NDMA was 0.29 μg/mL and 0.96 μg/mL, respectively, with an ethanol …

Influence Of The Reducing Agent Triphenylphosphine On Cyclooxygenase-1 Metabolism Of Arachidonic Acid, Rohini Sidhu

Master's Theses and Doctoral Dissertations

Cyclooxygenase (COX) metabolizes the polyunsaturated fatty acid arachidonic acid (AA) to PGG2, a cyclic endoperoxide that also contains a hydroperoxide, which is subsequently reduced to an alcohol in the enzyme to yield PGH2. Reactions catalyzed by COX-1 are significantly influenced by lipid hydroperoxides. The tyrosyl radical that abstracts the 13 pro(s) hydrogen from AA to initiate the COX catalytic cycle is generated by iron-oxo derivatives in the enzyme that result from lipid hydroperoxide interaction with heme iron. Commercial preparations of arachidonic acid (AA) contain lipid hydroperoxides that can be separated from AA by thin layer chromatography and readily reduced to …

Quantification Of Short-Chain Fatty Acids In Cecal Material By Gas Chromatography-Mass Spectrometry, Charles Harrison

Master's Theses and Doctoral Dissertations

Probiotic bacteria in the human colon that produce C₂ – C₄ short chain fatty acids (SCFA) and Lactobacillus species that produce lactate in addition to SCFAs are known to have positive health benefits. These organic acids were extracted with ether from murine cecal material (from Dr. Gary Huffnagle, Univ. of Mich.) and derivatized for quantitative measurement by gas chromatography-mass spectrometry. Antibiotic-treated animals gavaged with Candidaalbicans had a lower level of cecal butyrate relative to untreated animals, but a higher level of butyrate when treated mice were also administered Lactobacillus johnsonii NF-1. More recent studies have demonstrated a butyrate-lowering …

Effects Of Silver Nanoparticles On Photochemical Processes Focusing On Luminol Chemiluminescence, Scott Milam

Master's Theses and Doctoral Dissertations

Silver nanoparticles of varying sizes were synthesized. Their effects on enhancing or quenching the photochemical processes of tryptophan fluorescence, a ruthenium complex decay constant and chemiluminescence of luminol and ferricyanide, were studied. The tryptophan fluorescence was slightly enhanced by smaller nanoparticles and showed slight quenching in the presence of larger nanoparticles. The tris (2,2’-bipyridyl ruthenium (II) chloride) complex was excited using a 532 nm laser, and the decay constant was measured. Neither gold nor silver nanoparticles showed an impact on this process. The luminol chemiluminescence was studied with an emphasis on holding the concentration of nanoparticles, surface area, and silver …

Characterization Of The Binders In The Rock Art Of Cueva La Conga, Nicaragua, Ran Li

Master's Theses and Doctoral Dissertations

Cueva La Conga is the only known painted cave in Nicaragua, in a part of that country about which little is known archaeologically. The rock art, which includes carved rock formations as well as paintings and handprints, may provide clues about the past people and culture of this area. Archaeologists want to know if the paintings were influenced by the Maya to the north, or the Caribbean cultures to the east, or were a purely indigenous development. Determining the age of the paintings will help to understand the possible cultural relationships between known cultures and the rock art of Cueva …