Physical Sciences and Mathematics Commons^™

Biochemical Investigations Of Proteins Associated With Iron Homeostasis In Escherichia Coli, Matthew Ryan Blahut

Theses and Dissertations

The regulation of transition metals within living organisms is essential to the persistence of life. Of particular interest to our lab is iron due to the prevalence of this metal within the cell in addition to the numerous functions it performs. Fe-S cofactors are a significant prosthetic group consisting of iron that are necessary for the function of various metalloproteins. Generation of Fe-S clusters depends on several biosynthesis pathways varying between organisms with Isc and Suf both utilized in E. coli. While Isc controls Fe- S manufacturing under normal conditions, Suf assumes control when the cell is exposed to …

Investigation Of Energy-Related Wastewater Impacts On Disinfection By-Product Formation In Drinking Water, Hannah K. Liberatore

Theses and Dissertations

Elevated bromide and iodide in drinking water sources contribute to the formation of toxic brominated and iodinated disinfection by-products (DBPs) during drinking water treatment. Energy extraction and utilization processes, including hydraulic fracturing (HF) and coal-fired power plants (CFPPs), produce wastewaters with bromide/iodide levels on the order of tens to thousands of mg/L. These wastes have the potential to impact drinking water sources through both intentional (e.g., direct discharge) and accidental (e.g., basin overflow, spill) release pathways. This research focuses on a combination of quantitative and non-targeted approaches to assess DBP formation impacts from HF and CFPP wastewaters, with complementary toxicity …

Generalizing Metallocene Mechanochemistry To Ruthenocene Mechanophores, Ye Sha, Yudi Zhang, Enhua Xu, C Wayne Mcalister, Tianyu Zhu, Stephen L. Craig, Chuanbing Tang

Faculty Publications

Recent reports have shown that ferrocene displays an unexpected combination of force-free stability and mechanochemical activity, as it acts as the preferred site of chain scission along the backbone of highly extended polymer chains. This observation raises the tantalizing question as to whether similar mechanochemical activity might be present in other metallocenes, and, if so, what features of metallocenes dictate their relative ability to act as mechanophores. In this work, we elucidate polymerization methodologies towards main-chain ruthenocene-based polymers and explore the mechanochemistry of ruthenocene. We find that ruthenocene, in analogy to ferrocene, acts as a highly selective site of main …

Sustainable Polymers And Antimicrobial Biomaterials From Multicyclic Natural Products, Md Anisur Rahman

Theses and Dissertations

In this dissertation, the development of sustainable polymers and antimicrobial biomaterials from multicyclic natural products is illustrated. In Chapter 1, an overall background and recent development of sustainable polymers from natural product-based renewable biomass, antimicrobial biomaterials, and polymerization methods are introduced. Afterward, the primary research objectives of my doctoral research work are illustrated.

In chapter 2, designing block copolymer architectures toward tough bioplastics from renewable natural rosin was described. One of the most abundant natural biomasses is resin acids, however, most of the polymers derived from resin acids are brittle because of their bulky hydrophenanthrene pendant group. To overcome the …

Nanoscale Control Of Metal Oxideand Carbonaceous Functional Materials, Benjamin W. Lamm

Theses and Dissertations

The controlled fabrication of nanometer scale devices is of fundamental concern for numerous technologies, from separations to electronics and catalysis. The complexity of device architectures calls for the development of synthetic methods that independently control each feature: pore dimensions, wall thickness, and any subsequent functional nanomaterial layers (e.g. photoactive electrocatalysts). Precision control over these orthogonal methods can be used to integrate 3D and 1D nanostructures.

This dissertation presents the development of techniques useful in fabricating highly controlled nanoscale devices. The growth of single-phase bismuth vanadate (BiVO4) by atomic layer deposition (ALD) is demonstrated for the first time, allowing for the …

Development Of Acceptor-Integrated Crystalline Organic Materials, Brandon Yarbrough

Theses and Dissertations

We report the first example of fullerene-containing porous covalent-organic scaffold, which combines not only crystallinity and porosity, but also integrates the intrinsic properties of a redox-active buckyball, along with the ability to tune electronic properties. Thus, the presented studies not only demonstrate the possibility of merging the strong electron accepting properties of fullerene-based derivatives with the versatility of covalent-organic frameworks (COFs), but also begin the class of crystalline, entirely organic, donor-acceptor fullerene COFs through covalently modifying the channel walls. These studies could foreshadow new avenues for buckyball utilization for applications ranging from organic photovoltaics to molecular electronics.

Interfacial Ligand Dynamics And Chemistry On Highly Curved Nanoparticle Surfaces: A Plasmon-Enhanced Spectroscopic Study, Esteban Villarreal

Theses and Dissertations

The dynamic interactions between capping ligands and nanoparticle surfaces play a critical role in guiding shape-controlled nanocrystalline growth, imparting unique physical and chemical properties to the nanoparticles. It has been well established that nanoparticles within the size regime of sub 5 nm possess unique heterogeneous catalytic properties, while sub wavelength metallic nanoparticles exhibit tunable plasmonic activity, when these properties are integrated into a single nanoparticle, it presents a significant opportunity to monitor, in real time, the molecular transformations associated with interfacial interactions at the nanoparticle surface. Using plasmon-enhanced Raman scattering as an ultrasensitive spectroscopic tool combining molecular fingerprinting with time …

Catalytic Upgrading Of Aromatic Oxygenates Related To Lignin, Nicholas A. Delucia

Theses and Dissertations

Lignin is one component of lignocellulosic biomass and is the only renewable, naturally-occurring source of aromatics in the world. However, lignin also provides a highly-oxygenated, complex, heterogeneous structure making the procurement of isolated aromatic molecules quite difficult. There has been extensive research in recent years to develop approaches to catalytically breakdown the lignin polymer into monomeric units. This works aims to develop a number of catalytic techniques for the upgrading of these monomeric units of lignin to produce means for producing chemical building blocks as well as suitable fuels from biomass sources.

A method for the silanolysis of alcohols has …

Nanoparticles With Tunable Fluorophobic Effect Towards Multimodal Coassembly With Block Copolymers, Zachary Michael Marsh

Theses and Dissertations

Nanomaterials are often fabricated using block polymers to direct the placement of nanoparticles via selective intermolecular interactions such as hydrogen bonding. Fluorophobic interactions have emerged as a promising handle to control nanoparticle placement independently from typical hydrophilic approaches. A series of nanoparticles with tunable fluorophobicity were prepared to elucidate the key parameters for harnessing fluorophobic interactions in this context. Mixed ligand fluorinated nanoparticles (ML-FNPs) where prepared to examine the competing roles of each ligand towards fluorophobicity and solubility. The ML-FNP intermolecular interactions were first studied using a custom-made Quartz Crystalline Microbalance (QCM) based technique. The ML-FNPs were then examined for …

Structural And Functional Studies On 4-Hydroxy- Tetrahydrodipicolinate Reductase: Potential Drug Target In Bacteria, Swanandi Pote

Theses and Dissertations

Antimicrobial resistance has become an alarming public health concern since early 2000’s. Infections caused by multidrug resistant bacteria not only increase the mortality rate but also increase the economic burden globally. One approach to alleviate this issue is to find novel drug targets. In this regard, the bacterial lysine biosynthesis pathway provides several targets that may be used for design of antimicrobial compounds. Bacteria use lysine or meso-diaminopimelate to crosslink the peptidoglycan monomers in the bacterial cell wall. As such, we hypothesize that blocking this pathway will induce defects in the bacterial cell wall that are similar to those …

Development Of Nickel Catalyzed Cross-Coupling Methodologies, Ryan J. Key

Theses and Dissertations

In this work, we have addressed some of the issues surrounding catalytic crosscoupling reactions by using a nickel terpyridine catalyst, [Ni(tpy)(py)(CH3CN)2](PF6)2 in the Buchwald-Hartwig amination reaction and a functionalized variant, [(2,2':6',2''- terpyridine-4'-benzoic acid)Ni(II)]Cl2 on SiO2, in Suzuki coupling. These processes are unique in the approaches taken to achieve reactivity. In the Buchwald-Hartwig amination reaction, we used photoredox dual catalytic methods to achieve a sustainable approach to generate secondary and tertiary amines. This report is unique in many ways; most importantly, this method uses N-centered radicals to generate new C-N bonds. This report is also the first report to show generation …

Cooperative Lewis Pairs Based On High-Valent Early Transition Metal Halides And Synthesis Of Their Nitride Complexes, Md. Mamdudur Rahman

Theses and Dissertations

Herein, we report the activation of relatively strong C–H and C–O bonds under mild conditions by a cooperative interaction of TaCl5 and PPh3. An unprecedented activation of nitrile adducts of high-valent transition metals with the formation of novel zwitterionic imido complexes was observed. The scope of the reaction includes a range of substituted unactivated nitriles including the C–H bond activation of both aliphatic and aromatic nitriles.

The cooperative action of a Lewis acidic high-valent transition metal halide (TaCl5 or NbCl5) and a weakly nucleophilic base (NEt3 or PPh3) leads to the deprotonation of a coordinated nitrile and subsequent rearrangement to …

Emergent Properties And Applications Of Self- Assembled Benzophenone-Containing Materials, Baillie A. Dehaven

Theses and Dissertations

Supramolecular assembly of benzophenone through urea hydrogen bonding interactions facilitates the formation of remarkably persistent triplet radical pairs upon UV-irradiation at room temperature, whereas no radicals are observed in solution. The generation of organic radicals is correlated to the microenvironment around the benzophenone carbonyl, the types of proximal hydrogens, and the rigid supramolecular network. High-Field EPR and variable temperature X-band EPR accompanied by simulations suggest a resonance stabilized radical pair through hydrogen abstraction. Previous work has shown that UV-irradiation of self-assembled benzophenone bis-urea host results in low quantities of radical pairs that can be used to enhance NMR signals …

Impact Of Glutathione Transporters On Subcellular Glutathione Pools And Cell Survival In Saccharomyces Cerevisiae, Crystal Conaway Mcgee

Theses and Dissertations

Thiol-disulfide redox homeostasis is integral for maintaining the redox status of proteins and other thiol-containing molecules within cells. Mitochondria are particularly vulnerable to disruptions in redox balance, due to production of reactive oxygen species (ROS) during oxidative metabolism. Among the many antioxidants and detoxifying enzymes existing in mitochondria, glutathione (GSH) has proven to be critical for the preservation of function and structural integrity of the organelle. Therefore, our studies are aimed at elucidating the factors that control mitochondrial GSH metabolism in the model eukaryote Saccharomyces cerevisiae (baker’s yeast). A critical component of understanding subcellular GSH homeostasis is identifying routes of …

Metal-Organic Frameworks: Photophysics, Energy Transfer, And Electronic Structure, Ekaterina A. Dolgopolova

Theses and Dissertations

The current landscape of technological and industrial related fields is looking for novel materials with enhanced performances, which will not only improve various fields in science, but also can ensure increased environmental safety. Recently, metal-organic frameworks (MOFs) have been shown as a promising type of material for a wide range of applications including gas storage and separation, sensing, and heterogeneous catalysis. The main advantages of MOFs rely on their modular structures as well as their porosity. For instance, the modular nature of MOFs provides a control over chromophore arrangement, systematic tuning of ligand design and synthetic conditions allowing one to …

Anion Pool Directed Electroorganic Synthesis, D.M.M. Madushanka Mevan Dissanayake

Theses and Dissertations

The “Anion pool” approach introduces a greener approach for derivatization of pharmaceutically important molecules by amalgamating both electrochemistry and organic synthesis. This is a base and metal free procedure carried out in organic solvents recommended for pharmaceutical preparations. The anion pool procedure generates reactive nitrogen nucleophiles in situ via electrochemical reduction of heteroaromatic substrates. The adoption of such a methodology prevents generation of waste from bases used for deprotonation. Hydrogen is the main by-product of generation of anion pool, which, if produced at a large enough scale could be used as a renewable fuel. These attributes comply with the principles …

Kinetically Controlled Block Polymer Micelles: Cavitation Induced Exchange And Templates For Nanomaterials, Kayla Alice Lantz

Theses and Dissertations

Kinetically trapped micelles are emerging as a novel platform for a wide range of applications including drug delivery, nanoreactors, and templates for porous nanomaterials. Kinetic control affords decoupling of micelle size from subsequent applications. However, micelle homogenization and size tuning are inherently difficult due to the high barrier toward micelle chain exchange processes. These challenges can be resolved with the use of sonication, which enables switchable exchange where cavitation leads to chain exchange and cessation returns micelles to kinetic entrapment. Small-angle neutron scattering (SANS) measurements were used to quantify exchange during cavitation induced exchange (CIE). The extent of exchange was …

Ultra-Strong Long-Chain Polyamide Elastomers With Programmable Supramolecular Interactions And Oriented Crystalline Microstructures, Lingzhi Song, Tianyu Zhu, Liang Yuan, Jiangjun Zhou, Yaqiong Zhang, Zhongkai Wang, Chuanbing Tang

Faculty Publications

Polyamides are one of the most important polymers. Long-chain aliphatic polyamides could bridge the gap between traditional polyamides and polyethylenes. Here we report an approach to preparing sustainable ultra-strong elastomers from biomass-derived long-chain polyamides by thiol-ene addition copolymerization with diamide diene monomers. The pendant polar hydroxyl and non-polar butyrate groups between amides allow controlled programming of supramolecular hydrogen bonding and facile tuning of crystallization of polymer chains. The presence of thioether groups on the main chain can further induce metal–ligand coordination (cuprous-thioether). Unidirectional step-cycle tensile deformation has been applied to these polyamides and significantly enhances tensile strength to over 210 …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Exposure Characterization Of Haloacetic Acids In Humans For Exposure And Risk Assessment Applications: An Exploratory Study, Shahid Parvez, Jeffrey L. Ashby, Susana Y. Kimura, Susan D. Richardson

Faculty Publications

Disinfected water is the major source of haloacetic acids (HAAs) in humans, but their inter- and intra-individual variability for exposure and risk assessment applications is under-researched. Thus, we measured HAAs in cross-sectional and longitudinal urine and water specimens from 17 individuals. Five regulated HAAs—mono-, di-, and trichloroacetic acid (MCAA, DCAA, and TCAA) and mono- and dibromoacetic acid (MBAA and DBAA)—and one unregulated HAA—bromochloroacetic acid (BCAA)—were measured. Urinary DCAA, MBAA, DBAA, and BCAA levels were always below the limits of detection (LOD). Measured levels and interindividual variability of urinary MCAA were higher than urinary TCAA. Longitudinal urinary specimens showed MCAA levels …

Extra-Mitochondrial Cu/Zn Superoxide Dismutase (Sod1) Is Dispensable For Protection Against Oxidative Stress But Mediates Peroxide Signaling In Saccharomyces Cerevisiae, Claudia Montllor-Albalate, Alyson E. Colin, Bindu Chandrasekharan, Naimah Bolaji, Joshua L. Andersen, Franklin W. Outten, Amit R. Reddi

Faculty Publications

Cu/Zn Superoxide Dismutase (Sod1) is a highly conserved and abundant metalloenzyme that catalyzes thedisproportionation of superoxide radicals into hydrogen peroxide and molecular oxygen. As a consequence, Sod1serves dual roles in oxidative stress protection and redox signaling by both scavenging cytotoxic superoxideradicals and producing hydrogen peroxide that can be used to oxidize and regulate the activity of downstreamtargets. However, the relative contributions of Sod1 to protection against oxidative stress and redox signaling arepoorly understood. Using the model unicellular eukaryote, Baker's yeast, we found that only a small fraction ofthe total Sod1 pool is required for protection against superoxide toxicity and that …

The Effect Of Vinegar And Tap Water On The Release Of Nickel In Grade 304 Stainless Steel Cups, Caroline Quan

Journal of the South Carolina Academy of Science

Consumption of nickel rich liquids and foods pose a risk to human health, possibly causing reactions such as dermatitis. This study examines the amount of nickel that leaches out of grade 304 stainless steel cups with respect to time. The hypothesis of this experiment is that if given enough time, the liquids will react to the nickel in the stainless steel cups, and then nickel will leach out into the cup’s contents. The null hypothesis being that if the cups, since they are not given enough time and/or do not react to the nickel in the stainless steel cups, will …