Physical Sciences and Mathematics Commons^™

Theory And Improved Methods For Probing The Cavitation To Fracture Transition, Christopher Barney

Doctoral Dissertations

A material is considered soft when its bulk modulus is significantly greater than its shear modulus. Rubbery polymers are a class of soft materials where resistance to extension is mainly entropic in nature. Polymeric soft solids differ from liquids due to the presence of a percolated network of strong bonds that resist deformation and flow on a given time scale. The incompressible nature, entropically driven elasticity, and molecular scale network structure of soft polymeric solids combine to impart unique mechanical behavior that often results in complex material responses to simple loading situations. An important example of this is cavitation in …

Accurate Quantitation Of Hexavalent Chromium For Reference Standard Certification And Quality Control Testing Using Speciated Isotope Dilution Mass Spectrometry, James E. Henderson

Electronic Theses and Dissertations

The ability to perform accurate, repeatable, and defensible elemental and molecular speciated analysis is immensely significant for measurements that support human health, environmental science, and industry. This is especially true since trivalent chromium [Cr(III)] is necessary for proper nutrition, while hexavalent chromium [Cr(VI)] is extremely toxic, genotoxic, and carcinogenic. The main challenges associated with speciated analysis are related to reactive species that are continuously transformed or converted to other species during sample processing. Accurate determination of Cr(III) and Cr(VI) species require a method that is capable of monitoring and correcting for interconversion, bias, and instrumental error. Traditional quantitative methods, such …

Atom Transfer Radical Processes: From Catalyst Design To Polymer Synthesis, Characterization, And Application, Michael Novak

Electronic Theses and Dissertations

Due to the toxicity of heavy metals and their prevalence in the environment there exists a need to develop highly active transition metal catalysts ultimately reducing the amount needed for chemical transformations. Additionally, there is interest in the scientific community for creating new materials that can remove these pollutants from industrial wastewater prior to its release into the environment. The work presented here focuses on the reduction and removal of heavy metals from industrial hazardous waste by designing novel highly active catalysts and developing polymeric adsorbents.

Highly active catalyst complexes consisting of novel hybrid ligands, 2-(dimethylamino)ethyl-bis-[2-(pyridylmethyl)amine] (M1-T2), and bis[2-(dimethylamino)ethyl]-2-(pyridylmethyl)amine (M2-T1), …

Functionalized Materials From Atom Transfer Radical Processes, Sean Fischer

Electronic Theses and Dissertations

This work is focused on the synthesis, characterization, and application of functionalized materials prepared from atom transfer radical processes. Atom transfer radical processes encompass both atom transfer radical addition (ATRA) and polymerization (ATRP) reactions, both of which are catalyzed by ppm amounts of copper complexes. The synthetic efforts of ATRA include increasing adduct selectivity through optimization of reaction conditions to generate small molecules in high to moderate yields. ATRA provides retention of the halogen moiety, which is an attractive functional group that can be further modified with other transformations. Specifically, the copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) allows for the realization …

Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht

Electronic Theses and Dissertations

Pitting corrosion is arguably one of the most destructive and dangerous forms of corrosion, resulting in damage to structures, the environment, and public health. In addition, damage caused to structures such as bridges, pipelines, and boats, corrosion also has a profound effect on the biomedical community. Implanted metallic devices (i.e., vascular stents and artificial joints) are prone to pitting corrosion caused by aggressive ions present in extracellular fluid. To provide a corrosion-resistant surface on SS316L, films of poly(styrene), poly(methyl acrylate), and poly(methyl methacrylate) were formed using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting hydrophobic polymer films had a fractional …

Applied Molecular Dynamics: From Targeting Viral Helicases, To Understanding The Interactions Of Cucurbituril Complexes In Ionic Solutions, Bryan Raubenolt

University of New Orleans Theses and Dissertations

Molecular Dynamics simulations are a highly useful tool in helping understand the fundamental interactions present in a variety of chemical systems. The work discussed here illustrates it’s use in determining the conformational dynamics of the Zika and SARS-Cov-2 helicase in a physiological environment, largely in an effort to discover inhibitors capable of rendering the protein inert. Additionally, we show how it can be used to understand paradoxical trends in the anion-induced precipitation of Cucurbituril cavitands.

Viral helicases are motor proteins tasked with unwinding the viral dsRNA, a crucial step in preparing the strand to be translatable by host cells. By …

Investigating The Accumulation, Sub-Organ Distribution, And Biochemical Effects Of Nanomaterials Using Mass Spectrometry, Kristen Nicole Sikora

Doctoral Dissertations

Gold nanoparticles (AuNPs) are attractive materials for use in various biomedical applications, such as therapeutic delivery, due to their unique chemical properties and modular tunability. Mass spectrometry methods, including laser desorption/ionization mass spectrometry (LDI-MS) and inductively coupled plasma mass spectrometry (ICP-MS) have been successfully used to evaluate the distribution of AuNPs in complex biological systems. As new AuNP-based materials are developed for applications in therapeutic delivery, it is essential to simultaneously develop analytical techniques that can comprehensively assess their behavior in vivo. In this dissertation, novel mass spectrometric methods have been developed and utilized to evaluate the uptake, distribution, …

Understanding Biomass Upgrading Through Hydrogenolysis Reactions: Kinetics And Mechanism, Jalal Tavana

Electronic Theses and Dissertations

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H₂/D₂ kinetic isotope effect (KIE) experiment revealed that H₂ is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and …

An Intramolecular Method For The Formation Of Glycosidic Bonds, Sudeera Nadeeshani Kamburugamuwa Kamburugamuwe Loku Acharige

Electronic Theses and Dissertations

The improved understanding of carbohydrate functions in biological systems has increased the demand for well-characterized and pure carbohydrates in biomedical research. Chemical synthesis is the most feasible method to satisfy the scientific demand despite the inherent challenges of the glycosylation reaction. Therefore, it is essential to investigate novel methods for the formation of glycosidic bonds. In this work, an intramolecular method was developed using a thio-methylene-silyl linker to tether a glycosyl donor and acceptor. The glycosylation conditions resulted in the formation of both anomeric isomers with a preference for the inversion pathway, which is inconsistent with an entirely intermolecular glycosylation …

Fluorinated Phthalonitriles And Phthalocyanines: Synthesis And Spectroscopic Properties, Marius Pelmus

Seton Hall University Dissertations and Theses (ETDs)

Since their discovery at the beginning of the 20^th century, phthalocyanines (Pc) have come a long way; today they are replacing the porphyrins (natural products) in most of their applications. The functionalization of the organic macrocycle, the use of different metals, and the change of the axial ligands resulted in Pc applications in a wide range of fields, ranging from photochemistry, paints, catalysis, to fuel cells and cosmetic products.

In Dr. Gorun’s group was developed a series of electron-deficient Pcs that benefit from a Teflon-like chemical shield, meant also to break the π-π interactions, namely the F₆₄PcM …

Analysis Of Titanium Dioxide Nanoparticles In Foods Using Raman Spectroscopic Techniques, Janamkumar Pandya

Doctoral Dissertations

Titanium dioxide (TiO2) and its nanoparticles (NPs) are widely used in various applications. Recently, the presence of TiO2 NPs in food and consumer products raised safety concerns to human health and the environment. The goal of this project is to explore the capability of Raman Spectroscopy in the analysis of TiO2-NPs and apply this technique for the analysis of TiO2-NPs in food and environmental samples. Two approaches, i.e. the ligand-based and the mapping-based, were evaluated. The ligand-based approach utilized the surface enhanced Raman scattering (SERS) property of the TiO2 NPs as a substrate to enhance the signal of a surface …

Nanomaterial Composites Based On Potassium Hexaniobate, Perovskites, And Iron Triazole Spin Crossover Complexes, Alexis A. Blanco

University of New Orleans Theses and Dissertations

Development of novel materials with sought after properties has been the forefront in the field of nanomaterials. Hybrid nanomaterial architectures, or nanocomposites, is an important subgroup within the material chemistry umbrella. One such example of nanocomposite systems is peapod-like structures that are composed of 0D nanoparticles (“peas”) and 2D nanosheets (“pods”). Nanopeapods may display unique properties that were not attainable within individual components. BaTiO₃ nanoparticles can be produced using solvothermal methods (20 h) in the presence of Ba(NO₃)₂, titanium (IV) butoxide, and oleic acid as the surfactant. Synthesis parameters were modified to allow for both …

Hemithioindigo-Based Photoswitchable Self- Complementary Hydrogen Bond Arrays, Suendues Noori

Electronic Thesis and Dissertation Repository

Hydrogen bonded materials are slowly conquering grounds in the literature because of their dynamic features which stem from their reversible interactions. Incorporating the ability for light to chemically modify these interactions provides a unique template for innovative, efficient and self-healing materials. This thesis explores the design, synthesis, and characterization of nine derivatives of a well-known organic compound – hemithioindigo – with dual function; as a photoswitch and a novel self-complementary hydrogen bond array. The supramolecular complexes formed moderate to strong associations (63 M^-1 to 1100 M^-1) with spontaneous Gibbs free energy values (-10.3 kJ/mol to -17.3 kJ/mol) …

One-Pot Synthesis Of Bicyclic Piperidines From Donor Acceptor Cyclopropanes, David G. Stephens

Electronic Thesis and Dissertation Repository

The efficient synthesis of heterocyclic compounds is of great importance to organic chemistry. One method for achieving efficiency is through the use and development of one-pot reactions. This thesis describes the planning and development of an extension to the tandem cyclopropane opening Conia-ene reactivity previously reported. A search for a substrate capable of undergoing the reaction was undertaken and the reaction was optimized. The highest yielding conditions tested used catalytic Sc(OTf)₃ and superstoichiometric ZnBr₂, but other catalyst systems also worked. The optimized reaction conditions tolerated 6-membered rings well in addition to 7-membered rings in some rotationally restricted …

Thermally Stable Fluorogenic Zn(Ii) Sensor Based On A Bis(Benzimidazole)Pyridine-Linked Phenyl-Silsesquioxane Polymer, Chamika U. Lenora, Nai-Hsuan Hu, Joseph C. Furgal

Chemistry Faculty Publications

A 2,6-bis(2-benzimidazolyl) pyridine-linked silsesquioxane-based semi-branched polymer was synthesized, and its photophysical and metal-sensing properties have been investigated. The polymer is thermally stable up to 285 °C and emits blue in both solid and solution state. The emission of the polymer is sensitive to pH and is gradually decreased and quenched upon protonation of the linkers. The initial emission color is recoverable upon deprotonation with triethylamine. The polymer also shows unique spectroscopic properties in both absorption and emission upon long-term UV irradiation, with red-shifted absorption and emission not present in a simple blended system of phenylsilsesquioxane and linker, suggesting that a …

The Tolerance Of Shewanella Woodyi For Electric Potentials And Heavy Metals As Biofilms, Christopher Thomas Mortensen

Honors Theses

Shewanella woodyi is a bioluminescent marine organism that is known to be metal tolerant and modulate the intensity of its luminescence with electrochemical potential. The viability of S. woodyi as a bioreporter for the toxic heavy metal zinc, copper, and silver was analyzed. Biofilms of S. woodyi was grown on marine broth agar plates and then exposed to various concentrations of each metal ion to evaluate biofilm response to the metal ions that were generated from an operating short circuited electrode containing either Zn, Cu, or Ag metal. The ability of the bacteria to tolerate the heavy metals and continue …

Development Of Multi-Functional Molecular Systems For Applications On Nanomaterial Surfaces, Jun Hyeong Park

Electronic Thesis and Dissertation Repository

The glutathione-mediated, retro Michael-type addition reaction is demonstrated to take place at the interface of water-soluble, maleimide-functionalized gold nanoparticles (Maleimide-AuNP). The retro Michael-type addition can be blocked by hydrolyzing the Michael addition thioether adduct at the nanoparticle’s interface. This procedure “locks” the molecule of interest onto the Maleimide-AuNP template, ensuring no loss of the molecular cargo from the nanocarrier. On the other hand, the glutathione-mediated retro Michael-type addition reaction can be exploited for delivering a molecular payload. The Michael donor, 4-mercaptophenylacetic acid was modified with a terminal azide, allowing for addition of cargo through strain-promoted alkyne azide cycloadditions with various …

Synthesis Of Linear Oligo[N]Catenanes Via Orthogonal Metal Templation, Nathan Colley

Arts & Sciences Electronic Theses and Dissertations

No abstract provided.

Editorial Board

Karbala International Journal of Modern Science

No abstract provided.

Electrochemiluminescence Of A Di-Boron Complex, Perovskite And Carbon Quantum Dots, Jonathan M. Wong

Electronic Thesis and Dissertation Repository

The electrochemiluminescence (ECL) of three novel materials was explored in this thesis. A di-boron complex exhibiting crystallization-induced blue shift emission was detected utilizing photoluminescence. This phenomenon was successfully observed in the annihilation pathway, resulting in crystallization-induced blue shift ECL. The effects of coreactant and crystallization-induced enhancements were distinguished utilizing two testing systems. Undoped and Mn-doped CsPbCl₃ perovskites were investigated, as the latter exhibits a dual emissive photoluminescence pathway due to host and dopant emission mechanics. It was discovered that the electrochemiluminescence of Mn-doped CsPbCl₃ proceeds through a triplet-triplet annihilation pathway. Furthermore, the relaxation of the electrochemically generated Mn-doped …

In Silico Apc/C Substrate Discovery Reveals Cell Cycle-Dependent Degradation Of Uhrf1 And Other Chromatin Regulators, Jennifer L. Franks, Raquel C. Martinez-Chacin, Xianxi Wang, Rochelle L. Tiedemann, Thomas Bonacci, Rajarshi Choudhury, Derek L. Bolhuis, Taylor P. Enrico, Ryan D. Mouery, Jeffrey S. Damrauer, Feng Yan, Joseph S. Harrison, M. Ben Major, Katherine A. Hoadley, Aussie Suzuki, Scott B. Rothbart, Nicholas G. Brown, Michael J. Emanuele

College of the Pacific Faculty Articles

The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase and critical regulator of cell cycle progression. Despite its vital role, it has remained challenging to globally map APC/C substrates. By combining orthogonal features of known substrates, we predicted APC/C substrates in silico. This analysis identified many known substrates and suggested numerous candidates. Unexpectedly, chromatin regulatory proteins are enriched among putative substrates, and we show experimentally that several chromatin proteins bind APC/C, oscillate during the cell cycle, and are degraded following APC/C activation, consistent with being direct APC/C substrates. Additional analysis revealed detailed mechanisms of ubiquitylation for UHRF1, a key chromatin …

Synthesis Of The Oxidative Metabolites Of Di(2-Ethylhexyl) Phthalate And Analysis Of Metabolite Binding With Peroxisome Proliferator-Activated Receptors, Alexis Brooner

Student Research Submissions

Di(2-ethylhexyl) phthalate (DEHP) is a persistent organic pollutant that is added to increase the flexibility of soft plastics, such as polyvinyl chloride (PVC). Since DEHP is not bound to the polymer, it leaches into the environment, leading to human exposure. When DEHP is metabolized by the body, it is cleaved into mono-(2-ethylhexyl) phthalate (MEHP). MEHP is then oxidized to produce the secondary-oxidized metabolites mono-(2-ethyl-5-carboxypentyl)phthalate (5cx-MEPP), mono-(2-ethyl-5-oxohexyl)phthalate (5oxo-MEHP), and mono-[2-(carboxymethyl)hexyl]phthalate (2cx-MMHP). DEHP and its metabolites interact with peroxisome proliferator-activated receptors (PPARs), which can alter lipid metabolism. To synthesize 5cx-MEHP, an enolate alkylation was performed with ethyl butyrate to form ethyl 2-ethyl-6-heptenoate. …

Fabricating Cu2znsns4, Cu2znsn(S,Se)4 And Cuin(S,Se)2 Light-Absorbing Thin Films For Low-Cost Solar Devices., Vaishnavi Raja

Electronic Thesis and Dissertation Repository

In this thesis, Cu₂ZnSnS₄ (CZTS), Cu₂ZnSn(S,Se)₄ (CZTSSe) and CuIn(S,Se)₂ (CISSe) thin-films have been optimized to use as the key light-absorbing and conversion layer for solar cells. CZTS nanocrystals (NCs) were solvothermally synthesized, etched with acetic acid and structurally analyzed using synchrotron spectroscopy. Electrodeposited CZTSSe films showed a non-ideal increase in sulfur with lower selenization temperature and post-process etching. Compositional studies of electrodeposited CISSe films confirmed the decrease in selenium after the acetic acid etching. Through PECMs and other conventional characterization techniques, it was determined that non-etched CZTSSe and CISSe solar devices performed better …

Understanding The Role Of Atom Trapping In The Evolution Of Hydrocarbon Transformation Catalyst Morphology, Griffin Canning

Chemistry and Chemical Biology ETDs

Converting alkanes to other, more chemically and economically valuable molecules requires catalysts that can survive elevated temperatures and highly reducing environments. These environments can cause many metal-nanoparticle based catalysts to sinter rapidly, causing a loss of activity. They must also tolerate the coke formation, as well, since coke can restrict access to active sites by gas phase molecules, thus lowering catalytic activity. While there are routes to improve both the sinter and coke resistance of catalysts, an alternative strategy is to develop a protocol for regenerating the activity of the catalyst in question when coke formation or sintering becomes problematic. …

Synthesizing Octahedral Polyomavirus Capsids For Cryogenic Electron Microscopy, Miles Robertson

Fall Student Research Symposium 2020

Polyomavirus capsids are polymorphic under different chemical conditions. These capsids have been synthesized artificially using purified VP1, the primary building block of the capsid. Five VP1 proteins come together and form a highly stable structure called a pentamer, and these pentamers can form capsids (Figure 1). Depending on chemical conditions, the capsids can form three distinct sizes: T=7, octahedral and icosahedral (Figure 2). Only one form is found in infectious virions, and its structure has been well studied. However, no high-resolution structure of the octahedral capsid currently exists. The goal of this research is to solve the structure of the …

Enabling Mars Farms Through Microbial Remediation Of Wastewater, Tyler Wallentine

Fall Student Research Symposium 2020

This research evaluates the capacity of photoheterotrophic purple non-sulfur bacteria to utilize wastewater organics to grow and produce nitrogen-rich biomass. Inhibitory components of wastewater are determined. A scaled up production system is designed and utilized to culture bacteria in wastewater. The application of this technology in the production of agriculturally viable amounts of nitrogen-rich biomass is evaluated in the context of a Mars mission and enabling agriculture in a barren environment.

Why Dogs Are Feared, Hannah Ericson

Fall Student Research Symposium 2020

From German Shepherds to Pit bulls, a specific breed of dog is often singled out as being more dangerous than the others. There are stories and myths behind the behavior of such breeds, as well as simply looking scary. In this presentation, I will discuss why certain traits in dogs promote fear (such as dark coloring) and why certain breeds promote fear - such as a modern day prejudice that is quite similar to racism in the human society.

Cloning Type Iv-B Crispr System Into A Plasmid, Olivia Gornichec, Kailey Welch

Fall Student Research Symposium 2020

Bacterial CRISPR-Cas systems have recently been repurposed as RNA-guided genome editors in research labs across the world. Yet CRISPR-Cas adaptive immune systems are very diverse and many systems remain uncharacterized. Discovering the structure and function of newly discovered and uncharacterized systems may further advance existing genome editing technologies, or lead to new ones. To better understand the function of the little-researched Type IV-B system we cloned the genes of a Type IV-B system from Mycobacterium J623 into a plasmid containing a target sequence of a Type IV-A and Type V system. The Type IV-B system was placed on the target …

The Impact Of Biological Components On A Dog's Personality, Kinsley Batson

Fall Student Research Symposium 2020

We interact with dogs every day, and they are often referred to as "man's best friend." But what makes a dog the happy-go-lucky, cuddly fur ball of happiness that so many love? Similar to humans, there is a nature vs. nurture debate on what shapes a dog's personality. While it is likely a mixture of both, I've researched a variety of biological components that help to make a dog a dog. Some of these include face shape, how their brain responds to audio stimuli, and a specific gene, also found in children with Williams syndrome, that is thought to make …

Pure Breeding At Its Finest, Justin Hunter

Fall Student Research Symposium 2020

This is a poster of my research on the affects pure breeding has on dogs and their health. There is a focus as well on the focus on neoteny and its affects on dogs.