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A Monte Carlo Approach To Studying The Hydrogen Storage Capabilities Of Potassium Magnesium Hydride (Kmgh3), Brandon L. Borill

LSU Doctoral Dissertations

Grand Canonical Monte Carlo (GCMC) simulations and the weighted histogram analysis method (WHAM) were employed at selected temperatures and pressures in the study of the hydrogen storage capabilities of KMgH3. A specially tailored addition/removal algorithm was employed to add hydrogen directly at the lattice sites. Agreement between experimental results was obtained through GCMC simulations. WHAM type studies were employed to obtain probability distributions for the purpose of learning the probability of finding hydrogen atoms at specific temperatures and hydrogen pressures. The radial distribution function was employed to study the changes in the structure of KMgH3 for the selected model as …

Photoelectrons And Recombining Electrons In Atomic And Molecular Systems, Kristen D'Ann Fulfer

LSU Doctoral Dissertations

This work in this dissertation explores how photoelectrons enter and exit atoms and molecules. The electron rescattering events which may occur during photoionization or photorecombination processes play a dominant role in the understanding of how photoelectrons enter and exit molecules, which is intrinsically linked to how chemical reactions occur. Chapters 3-4 of this dissertation present evidence of vibrational mode specific breakdown of the Franck-Condon Principle in the photoionization of low symmetry molecules, acrolein and the singly halogenated thiophenes, due to resonant and non-resonant electron rescattering dynamics. In Chapters 5-6, the disentanglement of the valence electronic structure, as well as evidence …

Development Of New Linking Chemistry With The Fac-{Re(Co)3}+ Core For Eventual Applications In Radiopharmaceuticals In Imaging And Therapy, Aponsu Meregngna Pramuditha Lakmi Abhayawardhana

LSU Doctoral Dissertations

The facile labeling of biomolecules with a radionuclide is a key goal in radiopharmaceutical development. This study explores two different ligand systems for fac-[Re(CO)3L]+ complexes, that could be used in bioconjugation. The first approach uses a tridentate ligand having a sulfonamide linkage and modeled on previously evaluated fac-[Re(CO)3(N(SO2R)dpa)]PF6 complexes. The present goal was to develop new related sulfonamide complexes with more hydrophilic ligands designed to avoid the bioavailability problems that would plague the N(SO2R)dpa ligand system. A series of fac-[Re(CO)3(N(SO2R)dien)]PF6 complexes with different R groups linked to the central nitrogen of a symmetric tridentate sulfonamides were synthesized with the aim …

Illuminating The Interactions And Functions Of Glutaredoxins, Bola Proteins, And Erv1 In Iron Homeostasis, Adrian Colleen Dlouhy

Theses and Dissertations

Iron is a redox-active protein cofactor required for essential cellular functions such as respiration, however excess intracellular iron can generate damaging reactive oxygen species. Understanding how cells regulate iron levels is critical for treatment of human diseases that span from anemia to iron overload disorders. Glutaredoxins (Grxs) with a CGFS active site are highly conserved proteins shown to have roles in iron homeostasis and iron-sulfur cluster assembly, thus earning them the title “the Iron Whores”. They can exist either as a [2Fe-2S] cluster-bound dimer or an apo monomer, suggesting conservation of structure and function. In addition, Grxs interact with the …

Experimental And Computational Investigation Of Selected Β-Hydroxy Carbenes, Joseph D. Deangelo

Honors Theses

The photolytic precursor to the sterically hindered β-bis(tert)-butanol carbene, 3-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)-2,2,4,4-tetramethylpentan-3-ol was prepared in three steps from phenanthrene. Photolysis of the precursor generates the desired β-hydroxy carbene, an intermediate, which subsequently rearranges into two different observed products from an intramolecular C-H insertion and alkyl shift. Four intramolecular mechanisms were ultimately considered to account for the possible rearrangement pathways. Computational studies using density functional theory are also presented.

In addition, the photolytic precursors to two cyclic β-hydroxy carbenes, 1-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)cyclopropan-1-ol and 1-(1a,9b-dihydro-1H-cyclopropa[l]phenanthren-1-yl)cyclobutan-1-ol, were also prepared through different synthetic routes from phenanthrene. …

Chemically Patterned Surfaces As Test Platforms To Study Magnetic And Solvent-Responsive Properties At The Nanoscale: Investigations Using Scanning Probe Microscopy, Shalaka Kulkarni

LSU Doctoral Dissertations

Chemically patterned surfaces were fabricated using a combination of molecular self-assembly and particle lithography to generate billions of nanostructures of organosilane self-assembled monolayers (SAMs). Monodisperse mesospheres were used as surface masks to prepare nanostructures on flat surfaces using the simple benchtop chemistry steps of mixing, centrifuging, evaporation, and drying. Periodic arrays of well-defined organosilane nanostructures serve as discrete surface sites for the selective deposition of polymers and magnetic nanoparticles.

In this dissertation, particle lithography approaches for surface patterning provide new directions for studying surface chemistry at the molecular-level using high resolution investigations with scanning probe microscopy (SPM). Atomic force microscopy …

A Comparative Examination Of The Safety Programs At Ucla, Umn, And Uvm In Response To Recent Chemistry Laboratory Incidents, Victoria Carhart

Graduate College Dissertations and Theses

Laboratory safety has recently become more of an imperative in research laboratories than it has ever been in the past. Recent accidents at several universities have escalated the awareness of safety concerns in laboratory workspaces among the general public and created a greater need for a stronger culture of safety in chemistry research overall. Historically, results and publications have been the top priority of most researchers, not laboratory safety.

This thesis discusses a number of laboratory accidents. The first happened in December of 2008 at the University of California, Los Angeles (UCLA) and resulted in the death of a graduate …

Total Synthesis Of Clavatadine A Analogs To Produce A Viable Reversible Inhibitor For Factor Xia, Christopher E. Malmberg

All Master's Theses

Cardiovascular disease has quickly become a major health concern in the United States, with numerous citizens dying from cardiovascular disease each year. Older medications, while effective against cardiovascular disease, are problematic to prescribe. A recently isolated natural product, clavatadine A, selectively inhibits human blood coagulation factor XIa. As a result, the synthesis and biological testing of clavatadine A and synthetic clavatadine A analogues that selectively inhibit factor XIa would represent a new direction in cardiovascular disease research. A potent and selective factor XIa inhibitor has the potential to be a safer replacement for current anticoagulants, such as Warfarin, Pradaxa^{® …}

I. Synthesis Of Ascarosides For Biological Evaluation And Ii. Development Of Visible Light-Promoted Selenofunctionalization And Grafting Of Aryl Iodides, Elizabeth Susan Conner Balapitiya

LSU Doctoral Dissertations

This dissertation focuses on analog synthesis for biological evaluation and visible light promoted method development. Chapter 1 centers upon the synthesis of Caenorhabditis elegans dauer pheromone analogs. C. elegans is a nematode which, in times of environmental stress, enters a dauer stage. Two highly conserved pathways, which play important roles in some diseases in higher organisms, monitor dauer formation: TGF-β and IGF-1. Dauer formation is triggered by the nematode’s chemosensation of the dauer pheromone, consisting of a group of previously-isolated ascarosides. These compounds differ in chain length, saturation, terminal functionality of side chain, ω vs. ω-1 oxygenation and presence of …

Gold(Iii)-Catalyzed Cyclizations To Form Saturated Oxygen Heterocycles, Ryan D. Lyski

WWU Graduate School Collection

Gold catalysis has emerged over the past decade as an important methodology in the construction of organic molecules. Cationic gold complexes are robust, versatile, selective and efficient catalysts that can be used to enhance the electrophilicity of C-C unsaturated bonds. A current area of investigation is the use of gold to activate allylic alcohol/ether moieties for intramolecular S_N2’ nucleophilic attack to form oxygen heterocycles. We have discovered that sterically bulky, electron-withdrawing oxygen leaving groups drastically improved reaction efficiency, and bulky leaving groups in combination with substrate substituents enhanced diastereomeric ratios in the oxygen heterocycle products. These reactions proceeded …

Poly(Vinylpyridine) Nanostructures For Nanoparticle Synthesis And Energy-Related Catalysis, Audrey Taylor

WWU Graduate School Collection

Synthetic methodologies that allow for intentionally designed structures Pt_xM_100-x with a specified size, composition, and inter-particle spacing are key to advancing the field of energy-related catalysis. The synthesis of these catalytic nanostructures can be carried out using well-defined polymer frameworks that selectively retain catalyst precursors. Poly(vinylpyridine), (PVP) a polymer bearing pyridine residues is capable of metal-coordination or electrostatic association with metal anions in acidic media. In this work, we explore the synthesis of cross-linked PVP colloids and block copolymer templates capable of loading with catalyst precursors (ie: PtCl₆^2-, AuCl₄^-, IrCl_{6 …}

Electrospun Titanium Dioxide And Silicon Composite Nanofibers For Advanced Lithium Ion Batteries, Kathleen Mccormac

Electronic Theses and Dissertations

A unique electrospinning method was implemented to fabricate composite nanofibers for lithium ion battery applications. The composite nanofibers were made of amorphous carbon, rutile phase TiO₂, and cubic phase Si nanoparticles. Sulfur was utilized as a template to form void structures within the TiO₂ nanofiber matrix. This provides the desired space for the Si expansion during the lithiation process. Phase, structure, composition, and morphology of the nanofibers were characterized using Raman spectroscopy, SEM, EDS, TGA, and powder XRD. Carbonized TiO₂ nanofibers showed a low but stable specific capacity. Si Nanoparticles demonstrated an initially high but fast …

Total Synthesis Of Biologically Active Natural And Unnatural Products, Julia Heimberger

Electronic Theses and Dissertations

Herbarin A and B were isolated from the fungal strains of Cladosporium herbarum found in marine sponges Aplysina aerophoba and Callyspongia aerizusa. Total synthesis of Herbarin A and B was achieved by carrying out a multi-step synthesis approach, and the antioxidant properties were evaluated using FRAP assay. Toxicity of these compounds was determined using a zebrafish embryo model. Furthermore, synthesis of C-6 alkyl-azaarene derivatives of nucleosides by Csp3-H bond functionalization were investigated. Effective incorporation of 2-methylazaarene moiety at the C-6 position of the protected inosine nucleoside provided a new class of compounds with anticipated enhanced biological activity.

Structural Requirements For Ribosome-Dependent Gtpase Activity And Binding, Markus A. Carlson

WWU Graduate School Collection

The two billion years of evolution since the divergence of prokaryotes and eukaryotes has left earth with very few molecules conserved across these two domains of life. One such molecule, the ribosome, is an enormous ribonucleoprotein responsible for translation, the process of converting the information contained within an organism’s genetic code into functional proteins. Translation is facilitated by a number of other proteins, termed translation factors, required to catalyze the synthesis of these proteins. A large number of antibiotics prescribed today target either the ribosome or translation factors, and with increasing antibiotic resistance being found in infectious bacteria there is …

Profiling Sortase Substrate Specificity Using Peptide Libraries, Keyvan Dastkhosh Nikghalb

WWU Graduate School Collection

The use of enzymes for protein modification chemistry has gained traction in recent years due to the remarkable site-selectivity that enzymes afford. Among enzymes reported for this purpose, sortase A from Staphylococcus aureus (SrtAStaph) has garnered significant attention because of its selectivity, and its ability to install a wide range of non-natural modifications. In addition to SrtAStaph, it is now appreciated that sortase homologs exist in many bacterial strains, each with the potential to serve as a new catalyst for protein engineering. However, the majority of these enzymes has not been studied biochemically, and in order to utilize these enzymes …

Structural Studies Of Blood Coagulation Factor Viii In Protein Complexes, Michelle E. Wuerth

WWU Graduate School Collection

A deficiency in blood coagulation factor VIII (fVIII) is responsible for the inherited bleeding disorder hemophilia A, which affects approximately 1 in 5000 males. The development of inhibitory antibodies is a significant issue faced by hemophilia A patients receiving therapeutic infusions of fVIII. The C-terminal C2 domain of fVIII has been shown to be highly immunogenic and the site of binding for numerous antibodies of both the classical and non-classical classifications. A detailed understanding of the structural components involved in C2-antibody binding interactions is vital for the development of improved therapeutics for hemophilia patients. Here we present the structure of …

Probing The Hydrodesulfurization Properties Of Nickel-Rich Bimetallic Phosphides: Supported Catalysts And Encapsulated Nanoparticles, Samuel J. Danforth

WWU Graduate School Collection

The need for improved hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) catalysts is being driven by increasingly demanding requirements for ultralow sulfur fuels and by the fact that sulfur levels in crude oil have been trending upward over recent decades. Current industrial catalysts are based on molybdenum sulfide (MoS₂) and its highly anisotropic structure severely limits the number of exposed active sites. Transition metal phosphides (e.g. Ni₂P/SiO₂) are a new class of materials with promise to have improved properties relative to sulfided Ni-Mo/Al₂O₃ catalysts. The addition of a second metal can have large …

The Biogeochemistry Of Elemental Sulfur Contaminated Soils: Insights Into Effective Remediation, Michael Ryan Mctee

Graduate Student Theses, Dissertations, & Professional Papers

Soil contamination that results from elemental sulfur (S⁰) deposition is a new occurrence. Elemental sulfur is stockpiled as a byproduct from the oil and gas industry and is deposited by biodegradable trap and skeet targets at shooting ranges. Chemolithotrophs and mixotrophs can oxidize S⁰ to H₂SO₄. Consequently, in areas where excess S⁰ is deposited or stockpiled, soils can acidify to pH values observed with acid mine drainage.

I studied S⁰ contamination at a former sporting clay range. For seven years, the range used biodegradable trap and skeet targets that contained S …

Characterization Of Pm2.5 From Residential Woodstove Use For Source Apportionment Application, Virginia M. Porden

Graduate Student Theses, Dissertations, & Professional Papers

Results are presented for the comparative analysis of the PM_2.5 (Particulate Matter <2.5 µm) emissions from an EPA certified and a Traditional style wood stove using western larch. A total of 92 Quartz QMA 47mm filters were collected using a BGI PM_2.5 SSC (Sharp Cut Cyclone) sampler from each stove type and analyzed on a gas chromatograph-mass spectrometer against blank and deuterated internal standards. The results were analyzed using a Welch’s t-test (α > 0.05) to statistically differentiate between stove designs for temperature, mass, levoglucosan, resin acids (abietic and dehydroabietic), and polycyclic aromatic hydrocarbons [PAH] (acenaphthene, anthracene, benz(a)anthracene, pyrene, and retene). There was no statistical difference in levoglucosan PM_2.5 mass fraction between the stove types, yielding a mean levoglucosan fraction of 9.25% and 95% confidence interval of 8.43% …

Selective Solid Phase Extraction Of Uranium Using An Aminophosphonic Acid Functionalized Composite Material, Ranalda Tsosie

Graduate Student Theses, Dissertations, & Professional Papers

Uranium is an element of interest because it is an abundant source of concentrated energy. In 1948 the US offered money for uranium ore mined in the US, which created a mining boom in the southwest that included the Navajo Reservation. During the late 1960s the demand for uranium decreased and many mining operations shutdown and left behind a legacy of contamination. As a result many Navajo communities have numerous water sources that exceed established maximum contamination levels for uranium and other toxic metals. These contaminations are a direct result of abandoned Cold War uranium mines and mill waste sites …

Investigation Of Interferences And Development Of Pre-Treatment Methods For Arsenic Analysis By Anodic Stripping Voltammetry, Paul Lewtas

Theses: Doctorates and Masters

Contamination of drinking water is a serious health issue in many developing countries and there is a recognised need for low cost portable systems that are capable of analysing drinking water down to low ppb levels. Anodic Stripping Voltammetry (ASV) instruments meet these requirements but suffer interferences from other species which may also be present in the sample, particularly organics, other metals and sulfides. The last of these has received surprisingly little attention in the literature, despite being a proven interferent.

This study investigates the impact of each of these interference types, as well as a number of traditional and …