Digital Commons Network^™

Polymeric Porphyrins As Solar Photocatalysts, Nicholas Upton Day

Dissertations and Theses

Research concentrated on the absorption, transformation, and storage of light energy is useful for the energy challenges faced by humanity. In particular, photocatalysis using solar energy to generate useful fuels has become a primary research goal in the drive to replace fossil fuels for the future. In this dissertation it is shown that poly-tetra(4-aminophenyl)porphyrin (pTAPP) can be oxidatively polymerized using a variety of methods, including electropolymerization, chemical oxidation, and interfacial polymerization and that pTAPP has photocatalytic ability to reduce O₂ to H₂O₂ for a storable fuel.

Organic conductive polymers such as pTAPP are attractive catalysts because …

Design And Synthesis Of Novel Chloroquine-Based Antimalarials, Kevin Vincent Murphy

Dissertations and Theses

Malaria is an infectious, often fatal disease that afflicts nearly 200 million people every year. The disease, characterized by recurring and extreme flu-like symptoms, is caused by the protozoan parasite Plasmodium falciparum. Victims usually contract the disease through a mosquito vector. Chloroquine is a chemotherapeutic that was introduced in the 1940s. For many years the drug was the foremost treatment of malaria, being effective and producing few side effects. Unfortunately, tolerance to chloroquine developed when the parasite evolved a resistance mechanism. Newer drugs have been developed and implemented, but these medicines also show a decreasing effect with continued administration. …

Antimalarial Drug Discovery Using Triazoles To Overcome Chloroquine Resistance, Elias Sibhatu Tesfaselassie

Dissertations and Theses

Malaria is considered as one of the most prevalent and debilitating diseases affecting humans. Plasmodium falciparum is the most virulent form of the parasite which developed resistance to several antimalarial drugs. Chloroquine is one of the most successful antimalarials developed that is safe, effective, and cheap. However, its use has been limited due to the emergence of drug resistance. Click chemistry, particularly, the copper(I)-catalyzed reaction between azides and alkynes has shown to have a cutting-edge advantage in medicinal chemistry by its reliability, selectivity and biocompatibility.

Triazole-based antimalarials were synthesized via copper(I)-catalyzed alkyne-azide cycloaddition reaction by modifying the aliphatic chains terminal …

Rational Design Of Materials For The Protection Of Outdoor Metalworks, Natasja Alexandria Swartz

Dissertations and Theses

Protective coatings are commonly used to protect culturally significant works, such as outdoor sculptures and architectural elements. Given the valuable nature of such metalworks, there is a surprising lack of environmentally sustainable coatings available for their conservation. High performance clear coatings are not developed or thoroughly tested for compatibility and longevity on outdoor sculptures. This can make the implementation of both methods and materials, no matter how promising in a lab, a significant hurdle for the conservation science community. This dissertation work initially aims to replace high-VOC formulations such as acrylic lacquers and waxes currently used as protective coatings for …

The Influence Of Surface Chemistry On The Photoelectrochemical Properties Of Fes(2) Photoanodes, Qi Tong

Dissertations and Theses

The recurring theme of this dissertation is the correlation between FeS₂ surface chemistry and key electrical and electronic properties of FeS₂. Efforts have been made to identify and characterize the FeS₂ surface, investigate the photoelectrochemistry of FeS₂ photoanodes under anhydrous and anoxic conditions, and investigate the influence of deliberate surface chemistry on FeS₂ photoelectrochemistry.

Infrared reflection-absorption spectroscopy (IRRAS) was used to investigate a thin adsorbate layer on pyrite. The results showed that the combination of angle-dependent studies and computational efforts are a powerful tool for characterizing the pyrite surface.

The photoelectrochemistry of FeS_{2 …}

Characterization, Dna Binding And Cleavage Activities Of New Prodigiosin And Tambjamine Analogues And Their Cu²⁺ And Zn²⁺ Complexes, Karen Chichetu

Dissertations and Theses

Prodigiosins and tambjamines are natural compounds from bacterial and marine sources belonging to a family containing a common 4-methoxy-2,2'-bipyrrole core. These compounds have received a lot of interest due to their promising biological activities. Studies have suggested DNA as a potential therapeutic target for the natural prodigiosin and tambjamine due to their ability to facilitate oxidative DNA cleavage in the presence of Cu²⁺. Based on this we sought to study the metal binding activity of new prodigiosin and tambjamine analogues. A new prodigiosin analogue was synthesized and complexed with Cu²⁺. This revealed 1:1 complex formation between …

Steps Towards Deciphering The Post-Polyketide Synthase Tailoring Steps In The Phoslactomycin Biosynthesis Pathway, Patience Marimo

Dissertations and Theses

Phoslactomycins (PLMs) are a group of natural products belonging to a polyketides class. These polyketides are synthesized by sequential reaction catalyzed by a collection of enzymes activities called polyketide synthases. A polyketide is a large class of diverse compounds that are characterized by more than two carbonyl groups connected by single intervening carbon atoms. In other words, a polyketide is a polymer whose monomer is a ketide. The PLMs are also known as phosphazomycins or phospholines. These compounds were isolated based on antifungal and antitumor activities. This array of promising biological activities has stimulated research into the field of PLMs …

Development Of An Optical Method For The Detection Of Homocysteine As A Disease Biomarker Using Fluorescein-Aldehydes, Aabha Barve

Dissertations and Theses

Homocysteine is a natural occurring aminothiol. It is an intermediate product in the metabolism of methionine. Methionine is an essential amino acid required for protein synthesis. Metabolic irregularities disrupt homocysteine levels in plasma. Elevated homocysteine levels are directly linked to folate and cobalamin (vitamin B12) deficiencies, and are an independent risk factor for cardiovascular diseases. High homocysteine levels have also been associated with Alzheimer's, osteoporosis, renal failure, cancer, birth defects and pregnancy complications. The association of elevated homocysteine levels with cardiovascular disease and other diseases has generated great interest in the detection of homocysteine.

An optical method for the detection …

Facile Methods For The Analysis Of Lysophosphatidic Acids In Human Plasma, Jialu Wang

Dissertations and Theses

Lysophosphatidic acid (LPA) influences many physiological processes, such as brain and vascular development. It is associated with several diseases including ovarian cancer, breast cancer, prostate cancer, colorectal cancer, hepatocellular carcinoma, multiple myeloma atherosclerotic diseases, cardiovascular diseases, pulmonary inflammatory diseases and renal diseases. LPA plasma and serum levels have been reported to be important values in diagnosing ovarian cancer and other diseases. However, the extraction and quantification of LPA in plasma are very challenging because of the low physiological concentration and similar structures of LPA to other phospholipids. Many previous studies have not described the separation of LPA from other phospholipids, …

Spectroscopy, Nmr, And Electrochemistry Studies Of Protonated Aminophenyl/Pyridyl Porphyrins And Their Application In Hydrogen Evolution, Chenyi Wang

Dissertations and Theses

Spectrophotometric titrations for a full series of 4-aminophenyl/4-pyridyl meso-substituted porphyrins were carried out using methanesulfonic acid in DMSO to study the hyperporphyrin effect across different substitution patterns. The series included zero, one, two (cis and trans), three, and four meso(4-aminophenyl) groups, with the remaining meso substituents being 4-pyridyl groups. The peripheral pyridyl groups consistently protonate before the interior porphyrin pyrrole nitrogens, which protonate before the aminophenyl groups. Aminophenyl substituents increase the basicity of the pyrrole nitrogens and lead to distinctive hyperporphyrin spectra with a broad Soret band and a strong red absorption. The structure proposed to give rise to these …

Enzymatic Control Of The Related Pathways Of Fatty Acid And Undecylprodiginine Biosynthesis In Streptomyces Coelicolor, Renu Singh

Dissertations and Theses

Streptomyces coelicolor produces fatty acids for both primary metabolism and for production of the components of natural products such as undecylprodiginine. Primary metabolism makes the longer and predominantly branched-chain fatty acids, while undecylprodiginine utilizes shorter and almost exclusively straight chain fatty acids. The first step in fatty acid biosynthetic process is catalyzed by FabH (β-ketoacyl synthase III), which catalyzes a decarboxylative condensation of an acyl-CoA primer with malonyl-acyl carrier protein (ACP). The resulting 3-ketoacyl-ACP product is reduced by NADPH-dependent FabG into 3-hydroxyacyl-ACP, which is dehydrated by FabA to form enoyl-ACP. The NADH-dependent FabI (InhA) completes the cycle. Subsequent rounds of …

Degradation Of Carbon Tetrachloride Using Hydrophobic Green Rust, Sheena Bowman

Dissertations and Theses

Hydrophobic green rusts (GR) were produced using aerial oxidation of solutions containing bis (2-ethylhexyl) sulfosuccinate (BIS) and sodium N-lauroylsarcosinate (SNLS), iron (II) sulfate and sodium hydroxide. The synthesis was conduced at constant pH 8.0±0.1 for the duration of 1-3 hrs. Partition tests showed GRBIS and GRSNLS suspended in the organic phase (tetrachloroethylene). Through X-ray diffraction analysis both GRs exhibit similar patterns to Green Rust II, an inorganic form of GR. The kinetics of GR reductive dechlorination of carbon tetrachloride (CT) was investigated. CT at high concentrations was degraded at high percentages for GRBIS-3, 88.5% and GRSNLS-5, 97.6%. Their reactions were …