Chemistry Commons^™

Green Synthesis/Biosynthesis Of Silver Nanoparticles By Using Orange Peel Extract, Leela Joshi

Theses and Dissertations

Joshi, Leela, Green Synthesis/Biosynthesis of Silver Nanoparticles by Using Orange Peel Extract. Master of Science (MS), December, 2018, 40 pages, 23 figures, references, 36 titles. In this work, we report synthesis of silver nanoparticles (AgNPs) with an average size of ~6 nm. The aqueous solution of Ag+ ions is reduced using an aqueous extract from orange peel (Citrus Sinensis) at varying pHs. Reduction of Ag+ ions in solution was monitored using UV-visible absorption spectroscopy, and the corresponding surface plasmon resonance of AgNPs at 435 nm. The solution changed color from yellow to reddish-brown upon bioreduction of silver nitrate in orange …

Three Dimensional Carbon Nanotube Yarn Based Perovskite Solar Cells, Istiak Hussain

Theses and Dissertations

Perovskite solar cells (PSC) have emerged as a promising photovoltaic technology in lab scale with a short time of research due to their high power conversion efficiency, simple device fabrication, all solid-state structure and the possibility to ingrate the traditional device into fiber format. In this work, a three-dimensional (3D) perovskite solar cell is demonstrated using functionalized carbon nanotube yarn (CNT) as both cathode and anode. TiO2 and 2,2,7,-7-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (Spiro-OMeTAD) are used as the electron transporting and hole transporting material respectively. The TiO2 oxide layer is deposited on the top of the twisted carbon nanotube yarn and annealed with TiCl4 …

Effects On Altering Reaction Conditions In Suzuki Cross Coupling Reactions Using The Microwave, Javier Alejandro Perez

Theses and Dissertations

Over the last few decades, Suzuki coupling has become a common process for the synthesis of intermediates in pharmaceutical and industrial applications. It is well known that palladium is an effective catalyst for the formation of cross-coupled products. Therefore, this catalyst was tested in a series of reactions. Also, it is believed that other catalyst with similar properties to palladium can work, for example cerium. Therefore, a cerium hydroxide catalyst was synthesized in lab and used as a potential catalyst for the Suzuki reaction. For this study, some bases were investigated (NaOH, Na2CO 3, K3PO4, NaNO3, NaHCO3, etc) for the …

1. Synthesis And Characterization Of A Vanadium Based Transition State Mimic For Organophosphate Hydrolase 2. Catalytic Oxidation Of Thioanisole And 2-Chloroethyl Ethyl Sulfide Using Resin Bead Supported Oxoperoxidovanadium(V) Complexes, Efram Goldberg

Theses and Dissertations

Two vanadium(V) complexes were prepared for different projects. First the ONS tridentate ligand 14 was prepared according to literature procedure. This ligand was chosen to make the ONS dioxovanadium complex 15 for conjugation to a protein and to eventually elicit catalytic antibodies for the hydrolysis of the chemical weapon VX. Complex 15 was prepared in 65% overall yield and a full characterization was performed including X-ray diffraction. Initial screening performed at the Naval Research Laboratory indicated an IC50 of 84 nM for inhibition of a bacterial cholinesterase. It was also found to be 50% as effective as the control antiobiotic …

Data On Spectrum-Based Fluorescence Resonance Energy Transfer Measurement Of E. Coli Multidrug Transporter Acrb, Yuguang Cai, Thomas E. Wilkop, Yinan Wei

Chemistry Faculty Publications

This paper presented the dataset of correction parameters used in the determination of the energy transfer efficiencies from the spectrum-based fluorescence resonance energy transfer (FRET) measurement in a trimeric membrane protein AcrB. The cyan fluorescent protein (CFP) and yellow fluorescent protein (YPet) were used as the donor and acceptor, respectively. Two AcrB fusion proteins were constructed, AcrB-CFP and AcrB-YPet. The proteins were co-expressed in Escherichia coli cells, and energy transfer efficiency were determined in live cells. To obtain reliable energy transfer data, a complete set of correction parameters need to be first determined to accommodate for factors such as background …

Computational Quantum Chemistry Studies Of The Interactions Of Amino Acids Side Chains With The Guanine Radical Cation., Edward Acheampong

Electronic Theses and Dissertations

Guanine is generally accepted as the most easily oxidized DNA base when cells are subjected to ionizing radiation, photoionization or photosensitization. At pH 7, the midpoint reduction potential is on the order of 0.2 – 0.3 V higher than those of the radicals of e.g. tyrosine, tryptophan cysteine and histidine, so that the radical “repair” (or at least, a thermodynamically favorable reaction) involving these amino acids is feasible. Computational quantum studies have been done on tyrosine, tryptophan, cysteine and histidine side chains as they appear in histones. Density functional theory was employed using B3LYP/6-31G+ (d, p) basis set to study …

Relative Permittivity As A Function Of Co-Solvent And Impedance Spectroscopy For Quantifying Anions In Solution, Yahya Sami Alseiha

Electronic Theses and Dissertations

This work measured relative permittivity from 15.0 to 55.0 °C of aqueous solutions containing acetone or tetrahydrofuran using a BI 870 dielectric meter. A cubic polynomial fit resulted in coefficients for calculating permittivity as a function of temperature and mole fraction. Literature values for other co-solvent system resulted in similar polynomial coefficients. Using BI 870, permittivity measurements of ionic solutions were not possible because of high conductivity. A simple method using impedance spectroscopy measured these solutions. Impedance decreases with increasing temperature and decreases with increasing ionic strength. Due to the temperature dependence of impedance, all measurements were at 25.0 °C. …

Extraction And Purification Of Biologically Active Metabolites From Rhodococcus Sp. Mtm3w5.2, Mohrah Alenazi

Electronic Theses and Dissertations

Rhodococcushas been recognized as a potential antibiotic producer. Recently, a strain of Rhodococcussp. MTM3W5.2 was isolated from a soil sample collected in Morristown, Tennessee and was found to produce an inhibitory compound which is active against other related species. The purpose of this research is to extract, purify and analyze the active metabolite. The compound was extracted from RM broth cultures and purified by preliminary fractionation of crude extract through a Sephadex LH-20 column. Further purification was completed using semi-preparative reversed phase column chromatography. Final purification was obtained using multiple rounds of an analytical C18 HPLC column. Based …

Functional Materials, Device Architecture, And Flexibility Of Perovskite Solar Cell, Istiak Hussain, Hoang Phong Tran, Jared R. Jaksik, Justin Moore, Mohammed Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Perovskite solar cells (PSCs) are an emerging photovoltaic technology that promises to offer facile and efficient solar power generation to meet future energy needs. PSCs have received considerable attention in recent years, have attained power conversion efficiencies (PCEs) over 22%, and are a promising candidate to potentially replace the current photovoltaic technology. The emergence of PSCs has revolutionized photovoltaic research and development because of their high efficiencies, inherent flexibility, the diversity of materials/synthetic methods that can be employed to manufacture them, and the various possible device architectures. Further optimization of material compositions and device architectures will help further improve efficiency …

Quantum Mechanical Studies Of N-H···N Hydrogen Bonding In Acetamide Derivatives And Amino Acids, Sandra J. Lundell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Proteins are made of vast chains of amino acids that twist and fold into intricate designs. These structures are held in place by networks of noncovalent interactions. One of these, the hydrogen bond, forms bridges between adjacent pieces of the protein chain and is one of the most important contributors to the shape and stability of proteins. Hydrogen bonds come in all shapes and sizes and a full understanding of these not only aids in our understanding of proteins in general but can bridge the gap to finding cures to many protein-related diseases, such as sickle-cell anemia. The primary aim …

Inorganic Electrocatalysts For Innovative Water Splitting And Organic Upgrading, Nan Jiang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The booming worldwide demand for energy and the increasing concerns about global warming due to fossil fuel consumption have urged the development of techniques for storing and converting renewable and clean energy resources. Electrocatlytic or photoelectrocatalytic water splitting to generate green energy carrier H₂ with sustainable energy input, like solar, has been regarded as an attractive strategy for carbon-neutral energy needs. However, the sluggish kinetics for both half reactions (HER and OER), high overpotentials and thermodynamic requirements, and H₂ and O₂ gas crossover have been regarded as the major challenges, which limit its widespread application.

On account …

Carbon Monoxide On Demand: Light-Induced Co Release Of Flavonols, Stacey N. Anderson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Carbon monoxide (CO) is an extremely useful molecule with applications in industrial manufacturing, synthetic procedures as a C1 building block, and as a potential pharmaceutical to produce anti-inflammatory effects and vasodilation. However, the toxicity associated with CO has prevented its full utilization. In order to safely handle CO, compounds and molecules have been developed that act as storage materials for the gas. Ideal storage platforms only release CO upon stimulation via a trigger. Light activation is the most desirable trigger as it can be regulated in terms of the intensity and the wavelength of light used. The majority of light-induced …

Groundwater Hydrogeolgy And Hydrochemistry Of Karst Springs In The Eastern Peninsula Of Fort Hood Military Installation, William Scribner Welles

Electronic Theses and Dissertations

The eastern peninsula of Fort Hood Military Installation is underlain by a complex karst spring network. These springs are a primary water source in a protected habitat for endangered songbirds, which has only recently begun to be fully investigated. These Fredericksburg Group springs express both epigenetic and hypogenetic karst signatures. The study area is part of a paleo reef trend, a hydraulically disconnected segment of the northern section of the Edwards Aquifer. This study utilized standard ion index values, repeated measures, and principal component analyses on the chemical profiles of six perennial springs to classify spring water sources and their …

Molecular Dynamics Investigation Of The Thermodynamics Of Nanoscale Droplets And Kinetics Of Weakly Correlated Systems, Kai Yang Leong

Graduate Theses and Dissertations

The surface tension of nanoscale droplets of water was studied with molecular dynamics simulations using the BLYPSP-4F water potential. The internal pressure of the droplet was measured using a correlation between the pressure and density, established through a series of bulk simulations performed at pressures from 1 to 1000 bar. Such a procedure allows for reliable determination of internal pressure without the need to calculate the local Virial. The surface tension, estimated with the Young-Laplace relation, shows a good agreement with the Tolman equation with a Tolman length of -0.48 Å. The interface of a liquid water droplet is shown …

Investigation Of Electrolytic Flocculation For Microalga Scenedesmus Sp Using Aluminum And Graphite Electrodes, Shihong Liu, Husam A. Abu Hajar, Guy Riefler, Ben J. Stuart

Civil & Environmental Engineering Faculty Publications

Electrolytic flocculation using non-sacrificial electrodes with flocculants added was studied on harvesting Scenedesmus sp. In order to optimize the operating conditions of the electrolytic flocculation process and to quantify the amount of flocculants added, aluminum electrodes were first used in the process. It was found that under optimal conditions, the microalgae removal efficiency using aluminum electrodes could reach 98.5%, while 34.2 mg L^-1 of aluminum ions were released during the process. Different metal electrodes were also studied, but high microalgae removal efficiency was witnessed only using aluminum electrodes, indicating the influence of the aluminum ion in flocculation. When non-sacrificial …

Application Of A Hygroscopicity Tandem Differential Mobility Analyzer For Characterizing Pm Emissions In Exhaust Plumes From An Aircraft Engine Burning Conventional And Alternative Fuels, Max B. Trueblood, Prem Lobo, Donald E. Hagen, Steven C. Achterberg, Wenyan Liu, Philip D. Whitefield

Chemistry Faculty Research & Creative Works

In the last several decades, significant efforts have been directed toward better understanding the gaseous and particulate matter (PM) emissions from aircraft gas turbine engines. However, limited information is available on the hygroscopic properties of aircraft engine PM emissions which play an important role in the water absorption, airborne lifetime, obscuring effect, and detrimental health effects of these particles. This paper reports the description and detailed labbased performance evaluation of a robust hygroscopicity tandem differential mobility analyzer (HTDMA) in terms of hygroscopic properties such as growth factor (GF) and the hygroscopicity parameter (κ). The HTDMA system was subsequently deployed during …

Structure Of Native Lens Connexin 46/50 Intercellular Channels By Cryo-Em, Janette B. Myers, Bassam G. Haddad, Susan E. O'Neill, Dror S. Chorev, Craig C. Yashioka, Carol V. Robinson, Daniel M. Zuckerman, Steve L. Reichow

Chemistry Faculty Publications and Presentations

Gap junctions establish direct pathways for cell-to-cell communication through the assembly of twelve connexin subunits that form intercellular channels connecting neighbouring cells. Co-assembly of different connexin isoforms produces channels with unique properties and enables communication across cell types. Here we used single-particle cryo-electron microscopy to investigate the structural basis of connexin co-assembly in native lens gap junction channels composed of connexin 46 and connexin 50 (Cx46/50). We provide the first comparative analysis to connexin 26 (Cx26), which—together with computational studies—elucidates key energetic features governing gap junction permselectivity. Cx46/50 adopts an open-state conformation that is distinct from the Cx26 crystal structure, …

Binding Of Telomestatin, Tmpyp4, Bsu6037, And Braco19 To A Telomeric G-Quadruplex-Duplex Hybrid Probed By All-Atom Molecular Dynamics Simulations With Explicit Solvent., Holli-Joi Sullivan, Carolyn Readmond, Christina Radicella, Victoria Persad, Thomas J Fasano, Chun Wu

College of Science & Mathematics Departmental Research

A promising anticancer therapeutic strategy is the stabilization of telomeric G-quadruplexes using G-quadruplex-binding small molecules. Although many G-quadruplex-specific ligands have been developed, their low potency and selectivity to G-quadruplexes over duplex remains unsolved. Recently, a crystal structure of a telomeric 3' quadruplex-duplex hybrid was reported and the quadruplex-duplex interface was suggested to a good target to address the issues. However, there are no high-resolution complex structures reported for G-quadruplex ligands except for a docked BSU6037. In this study, molecular dynamic (MD) binding simulations with a free ligand were used to study binding poses and dynamics of four representative ligands: telomestatin, …

Global Minimum Search And Carbon Monoxide Binding Studies Of Novel Gold Nanoclusters, Navneet S. Khetrapal

Department of Chemistry: Dissertations, Theses, and Student Research

In bulk form, gold is a well-known noble metal. However, gold nanoparticles exhibit remarkable catalytic behavior towards various types of chemical reactions. These catalytic properties are highly dependent upon the size and shape and therefore knowledge of the geometries of these nanoparticles is of prime importance. The main goal of this dissertation is, therefore, going to be towards the elucidation of the structures of novel gold clusters using a combined experimental and theoretical approach and subsequent modeling to explore the binding of simple substrates like carbon monoxide with gold clusters. The theoretical method used to study the structural evolution of …

A Gcn5-Related N-Acetyltransferase (Gnat) Capable Of Acetylating Polymyxin B And Colistin Antibiotics In Vitro, Mateusz P. Czub, Brian Zhang, M. Paul Chiarelli, Karolina A. Majorek, Layton Joe, Pryemyslaw J. Prebski, Alina Revilla, Weiming Wu, Daniel P. Becker, Wladek Minor, Misty L. Kuhn

Chemistry: Faculty Publications and Other Works

Deeper exploration of uncharacterized Gcn5-related N-acetyltransferases has the potential to expand our knowledge of the types of molecules that can be acylated by this important superfamily of enzymes and may offer new opportunities for biotechnological applications. While determining native or biologically relevant in vivo functions of uncharacterized proteins is ideal, their alternative or promiscuous in vitro capabilities provide insight into key active site interactions. Additionally, this knowledge can be exploited to selectively modify complex molecules and reduce byproducts when synthetic routes become challenging. During our exploration of uncharacterized Gcn5-related N-acetyltransferases from Pseudomonas aeruginosa, we identified such an …

Near-Infrared Photoluminescence And Electrochemiluminescence From An Exceptionally Simple Boron Difluoride Formazanate Dye, Ryan R. Maar, Ruizhong Zhang, David G. Stephens, Zhifeng Ding, Joe Gilroy

Chemistry Publications

Electrochemiluminescence involves the generation of light via electrochemical reactions and has recently shown utility for single-cell imaging. To further develop this novel imaging platform, it is necessary to produce readily available dyes that photoluminesce and electrochemiluminesce in the near-infrared region to limit absorption by biological tissue. To address this need, we prepared a boron difluoride formazanate dye that exhibits near-infrared photoluminescence and electrochemiluminescence in two straightforward synthetic steps. Examination of its solid-state structure suggests that the N-aryl substituents have significant quinoidal character, which narrows the S₁-S₀ energy gap and leads to near-infrared absorption and photoluminescence. Electrochemical …

Molecular Fossils From Phytoplankton Reveal Secular Pco2 Trend Over The Phanerozoic, Caitlyn R. Witkowski, Johan W. H. Weijers, Brian S. Blais, Stefan Schouten, Jaap S. Sinninghe Damsté

Science and Technology Department Faculty Journal Articles

Past changes in the atmospheric concentration of carbon dioxide (PCO2) have had a major impact on earth system dynamics; yet, reconstructing secular trends of past PCO2 remains a prevalent challenge in paleoclimate studies. The current long-term PCO2reconstructions rely largely on the compilation of many different proxies, often with discrepancies among proxies, particularly for periods older than 100 million years (Ma). Here, we reconstructed Phanerozoic PCO2 from a single proxy: the stable carbon isotopic fractionation associated with photosynthesis (Ɛp) that increases as PCO2 increases. This concept has been widely applied to alkenones, but here, we …

Nano To Global: Small Structures And Their Impact On Energy Markets, Kurt W. Kolasinski

Sustainability Research & Practice Seminar Presentations

No abstract provided.

High-Throughput Assessment Of A Novel, Thiol-Acrylate Hydrogel For Tumor Spheroid Synthesis In A Microfluidic Device, Nathan Daniel Kersker

LSU Master's Theses

The extracellular environment plays an important role in regulating cell behavior. The mechanical, structural, and compositional properties of the extracellular matrix can determine the fate of the growing cells. Standard two-dimensional culturing in a flask fails to represent a native cellular environment. To create the native environment suitable for cells, hydrogels were previously studied. One of the most extensively studied synthetic hydrogels was a poly(ethylene glycol diacrylate) (PEGDA) hydrogel. However, the need for UV polymerization may introduce unwanted changes in cell morphology and viability. The hydrogel being proposed was a form of a thiol-acrylate hydrogel that can eliminate this problem …

Synthesis And Characterization Of Cobalt(Ii) N,N′‑Diphenylazodioxide Complexes, Kylin A. Emhoff, Lakshmi Balaraman, Sydney R. Simpson, Michael L. Stromyer, Haitham F. Kalil, James R. Beemiller, Philipp Sikatzki, Teya S. Eshelman, Ahmed M.H. Salem, Michael A. Debord, Matthew J. Panzer, Wiley J. Youngs, W. Christropher Boyd

Chemistry Faculty Publications

Removal of chloride from CoCl₂ with TlPF₆ in acetonitrile, followed by addition of excess nitrosobenzene, yielded the eight-coordinate cobalt(II) complex salt [Co{Ph(O)NN(O)- Ph}₄](PF₆)₂, shown by single-crystal X-ray analysis to have a distorted tetragonal geometry. The analogous treatment of the bipyridyl complex Co(bpy)Cl₂ yielded the mixed-ligand cobalt(II) complex salt [Co(bpy){Ph(O)NN(O)Ph}₂](PF₆)₂, whose singlecrystal X-ray structure displays a trigonal prismatic geometry, similar to that of the iron(II) cation in the previously known complex salt [Fe{Ph(O)NN(O)Ph}₃](FeCl₄)₂. The use of TlPF₆ to generate …

Spontaneity, Carl W. David

Chemistry Education Materials

An attempt is made to better understand thermodynamic spontaneity.

Erratum: “Several Levels Of Theory For Description Of Isotope Effects In Ozone: Effect Of Resonance Lifetimes And Channel Couplings”, Alexander Teplukhin, Igor Gayday, Dmitri Babikov

Chemistry Faculty Research and Publications

No abstract provided.

Decreasing Phosphatidylcholine On The Surface Of The Lipid Droplet Correlates With Altered Protein Binding And Steatosis, Laura Listenberger, Elizabeth Townsend, Cassandra Rickertsen, Anastasia Hains, Elizabeth Brown, Emily G. Inwards, Angela K. Stoeckman

Chemistry Faculty Publications

Alcoholic fatty liver disease (AFLD) is characterized by an abnormal accumulation of lipid droplets (LDs) in the liver. Here, we explore the composition of hepatic LDs in a rat model of AFLD. Five to seven weeks of alcohol consumption led to significant increases in hepatic triglyceride mass, along with increases in LD number and size. Additionally, hepatic LDs from rats with early alcoholic liver injury show a decreased ratio of surface phosphatidylcholine (PC) to phosphatidylethanolamine (PE). This occurred in parallel with an increase in the LD association of perilipin 2, a prominent LD protein. To determine if changes to the …

First-Principles Structural, Mechanical, And Thermodynamic Calculations Of The Negative Thermal Expansion Compound Zr2(Wo4)(Po4)2, Philippe F. Weck, Eunja Kim, Margaret E. Gordon, Jeffrey A. Greathouse, Remi Dingreville, Charles R. Bryan

Physics & Astronomy Faculty Research

The negative thermal expansion (NTE) material Zr2(WO4)(PO4)2 has been investigated for the first time within the framework of the density functional perturbation theory (DFPT). The structural, mechanical, and thermodynamic properties of this material have been predicted using the Perdew, Burke and Ernzerhof for solid (PBEsol) exchange–correlation functional, which showed superior accuracy over standard functionals in previous computational studies of the NTE material α-ZrW2O8. The bulk modulus calculated for Zr2(WO4)(PO4)2 using the Vinet equation of state at room temperature is K0 = 63.6 GPa, which is in close agreement with the experimental estimate of 61.3(8) at T = 296 K. The …

Regeneration Of Aged Dmf For Use In Solid-Phase Peptide Synthesis, Jordan K. Magtaan, Marc Devocelle, Fintan Kelleher

Articles

DMF, which is still the most commonly used solvent for Fmoc-SPPS, has the potential for degradation over time on exposure to air (and water vapour) and storage, to give dimethylamine and formic acid impurities. In particular, dimethylamine can lead to unwanted deprotection of the Fmoc group during for example the initial loading of Fmoc amino acids in SPPS, which leads reduced calculated loading values. We have found that treatment of such aged DMF by simple sparging with an inert gas (N₂), or vacuum sonication, can regenerate the DMF in order to restore loading levels back to those found …