Chemistry Commons^™

Substrate Specificity Of The Lipn Hydrolase From Mycobacterium Ulcerans, Stephanie Raynor

Undergraduate Honors Thesis Collection

Mycobacterium ulcerans is the causative agent of Buruli ulcer, a tropical skin disease that affects thousands of individuals annually. Recent studies have revealed that lipolytic enzymes are involved in the pathogenicity processes of mycobacterium and could be potential targets for novel antibiotics. LipN is one proposed serine hydrolase in Mycobacterium ulcerans that contains the conserved α/β hydrolase protein fold and utilizes the conserved catalytic traid of serine, histidine, and aspartate/glutamate. The physiological substrate and biological role of LipN from M. ulcerans have not yet been determined. In this study, LipN was cloned into a pET28a plasmid and overexpressed in an …

Mutation Of Surface Histidines In Haemophilus Influenzae Carbonic Anhydrase To Enable Purification By Metal Affinity Chromatography, Shelby E. Scola, Kathleen Cornely

Chemistry & Biochemistry Student Scholarship

No abstract provided.

Electrodeposition And Characterization Of Metals And Metal Oxides For Energy Conversion And Storage, Ying-Chau Liu

Doctoral Dissertations

"This dissertation investigates the electrodeposition of metal and metal oxide thin films applicable to solar water splitting cells. Paper I describes the synthesis of cobalt hydroxide, ß-Co(OH)₂, by electrochemically reducing tris(ethylenediamine)cobalt(III) in alkaline solution. Paper II presents a scheme to convert the ß-Co(OH)₂ to CoOOH and Co₃O₄ and compares their catalytic activity for the oxygen evolution reaction. Co₃O₄ appears to be a more active catalyst than CoOOH based on Tafel analysis. However, when the observed current densities are corrected for the measured electrochemically active surface area, the linear region of the …

Targeting Radioresistant Breast Cancer Cells By Single Agent Chk1 Inhibitor Via Enhancing Replication Stress, Yao Zhang, Jinzhi Lai, Zhanwen Du, Jinnan Gao, Shuming Yang, Shashank Gorityala, Xiahui Xiong, Ou Deng, Zhefu Ma, Chunhong Yan, Gonzalo Susana, Yan Xu, Junran Zhang

Chemistry Faculty Publications

Radiotherapy (RT) remains a standard therapeutic modality for breast cancer patients. However, intrinsic or acquired resistance limits the efficacy of RT. Here, we demonstrate that CHK1 inhibitor AZD7762 alone significantly inhibited the growth of radioresistant breast cancer cells (RBCC). Given the critical role of ATR/CHK1 signaling in suppressing oncogene-induced replication stress (RS), we hypothesize that CHK1 inhibition leads to the specific killing for RBCC due to its abrogation in the suppression of RS induced by oncogenes. In agreement, the expression of oncogenes c-Myc/CDC25A/c-Src/H-ras/E2F1 and DNA damage response (DDR) proteins ATR/CHK1/BRCA1/CtIP were elevated in RBCC. AZD7762 exposure led to significantly higher …

The Dawn Of New Quantum Dots: Synthesis And Characterization Of Ge1-Xsnx Nanocrystals For Tunable Bandgaps., Richard J. Esteves

Theses and Dissertations

Ge_1-xSn_x alloys are among a small class of benign semiconductors with composition tunable bandgaps in the near-infrared spectrum. As the amount of Sn is increased the band energy decreases and a transition from indirect to direct band structure occurs. Hence, they are prime candidates for fabrication of Si-compatible electronic and photonic devices, field effect transistors, and novel charge storage device applications. Success has been achieved with the growth of Ge_1-xSn_x thin film alloys with Sn compositions up to 34%. However, the synthesis of nanocrystalline alloys has proven difficult due to larger discrepancies (~14%) in …

Calculating Potential Energy Curves With Fixed-Node Diffusion Monte Carlo: Co And N₂, Andrew D. Powell, Richard Dawes

Chemistry Faculty Research & Creative Works

This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N₂ were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could …

Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo

Electronic Theses and Dissertations

Heart disease is the leading cause of death in the United States. Understanding heart function at the molecular level is critical for developing of more effective treatments. In the cardiac muscle, the thin filament is composed by troponin (Tn), tropomyosin (Tm), and F-actin. It provides Ca2+-dependent regulation of contraction by modulating myosin attachment and force generation in a cooperative scheme. However, this mechanism remains unclear. To understand thin filament activation, we studied the binding and functional properties of Tn and Tm to F-actin at single particle resolution by employing fluorescence image colocalization, in vitro motility assays, and Förster resonance energy …

Use Of Extraction Technologies In Food Safety Studies, Changling Qiu

Electronic Theses and Dissertations

Food safety has become a top concern in our society. The public in general is increasingly concerned about the safety of the food products they consume every day as more and more food contamination incidents and widespread recalls arise. It is necessary to trace any presence and/or the concentration levels of contaminants, pesticides, herbicides, or other harmful substances in food samples. Sample preparation is a crucial step in a food analytical method, as it takes up most of the total analysis time, contributing highly to the total cost of analysis and greatly influencing the results of the analysis. Traditional extraction …

Tio2-Based Nanomaterials For Advanced Environmental And Energy-Related Applications, Xujie Lü, Baoyu Xia, Yefeng Yang, Hao Tang

Physics Faculty Publications

No abstract provided.

A Novel Copper (Ii) Complex Identified As A Potent Drug Against Colorectal And Breast Cancer Cells And As A Poison Inhibitor For Human Topoisomerase Iiᶐ, Shayna Sandhaus, Rosella Taylor, Tiffany Edwards, Alexis Huddleston, Stephen J. Beebe, Alvin A. Holder

Bioelectrics Publications

A novel complex, [Cu(acetylethTSC)Cl]Cl · 0.25C₂H₅OH 1 (where acetylethTSC = (E)-N-ethyl-2-[1-(thiazol-2-yl)ethylidene]hydrazinecarbothioamide), was shown to have anti-proliferative activity against various colon and aggressive breast cancer cell lines. In vitro studies showed that complex 1 acted as a poison inhibitor of human topoisomerase IIᶐ which may account for the observed anti-cancer effects.

Thiol-Acrylate Polymerization Kinetics And Applications In Microfluidics, Michael Perrin Tullier

LSU Doctoral Dissertations

The reaction kinetics and some applications in the field of microfluidics for thiol-acrylate Michael addition polymerizations using multifunctional monomers have been researched and are presented here. The polymerization rate constants for base-catalyzed systems were found to increase with increasing thiol and acrylate functionality, which was attributed to the intramolecular interactions between functional groups. The nucleophile-initiated thiol-acrylate Michael addition polymerization kinetics were monitored via FTIR, and it was determined that the increase in the rate of reaction in these multifunctional systems was significantly less dramatic than the increase observed in monofunctional systems. While no radical polymerization was observed during most typical …

Crystal Structure Of Ethyl 4-[(E)-(4-Hy-Droxy-3-Meth-Oxy-Benzyl-Idene)Amino]-Benzoate: A P-Hy-Droxy Schiff Base, Jing Ling, Padmini Kavuru, Lukasz Wojtas, Keith Chadwick

Chemistry Faculty Publications

The title p-hy-droxy Schiff base, C17H17NO4, was synthesized via the condensation reaction of benzocaine with vanillin. The benzyl-idine and benzoate rings are inclined to one another by 24.58 (8)°, and the conformation about the C=N bond is E. In the crystal, mol-ecules are linked by O-H⋯N hydrogen bonds, forming zigzag chains propagating along [010]. Adjacent chains are linked by C-H⋯π and weak offset π-π inter-actions [inter-centroid distance = 3.819 (1) Å], forming sheets parallel to (10-2).

Inactivation Of Peptidylglycine Α-Hydroxylating Monooxygenase By Cinnamic Acid Analogs, Neil R. Mcintyre, Edward W. Lowe Jr, Matthew R. Battistini, James W. Leahy, David J. Merkler

Chemistry Faculty Publications

Peptidylglycine α-amidating monooxygenase (PAM) is a bifunctional enzyme that catalyzes the final reaction in the maturation of α-amidated peptide hormones. Peptidylglycine α-hydroxylating monooxygenase (PHM) is the PAM domain responsible for the copper-, ascorbate- and O₂-dependent hydroxylation of a glycine-extended peptide. Peptidylamidoglycolate lyase is the PAM domain responsible for the Zn(II)-dependent dealkylation of the α-hydroxyglycine-containing precursor to the final α-amidated peptide. We report herein that cinnamic acid and cinnamic acid analogs are inhibitors or inactivators of PHM. The inactivation chemistry exhibited by the cinnamates exhibits all the attributes of a suicide-substrate. However, we find no evidence for the formation …

Crystal Engineering Of A Family Of Hybrid Ultramicroporous Materials Based Upon Interpenetration And Dichromate Linkers, Hayley S. Scott, Naoki Ogiwara, Kai-Jie Chen, David G. Madden, Tony Pham, Katherine Forrest, Brian Space, Satoshi Horike, John J. Perry Iv, Susumu Kitagawa, Michael J. Zaworotko

Chemistry Faculty Publications

A new family of 2-fold interpenetrated primitive cubic (pcu) networks of formula [M(L)₂(Cr₂O₇)]_n (M = Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺; L = 4,4′-azopyridine), DICRO-3-M-i, has been synthesised and their structures, permanent porosity and gas sorption properties were comprehensively characterised. Molecular simulations indicate that CO₂ molecules occupy both of the two distinct ultramicropores that run through this isostructural series. The orientation of the Cr₂O₇²⁻ pillars is thought to contribute to high isosteric enthalpy of adsorption (Q_st) …

Phenanthrene...With A Twist!, Nicholas S. Kim

Honors Theses

The twisted and sterically hindered 4,5-dibromophenanthrene, was synthesized from 2,6-dibromoiodobenzene in a four-step pathway, or from 1,3-dibromobenzene in a three-step pathway. Then, 4,5-dibromophenanthrene was subjected to a Kumada coupling, leading to the synthesis of an even more twisted 4-bromo-5-tert-butylphenanthrene. Computational studies using density functional theory were performed to compare experimental and theoretical characteristics of these compounds, such as dihedral angles, optimized structures, and transition state energy barriers.

The purpose of these experiments is to fill gaps in chemical databases, synthesize more pronounced twists in normally planar phenanthrene molecules, and to ultimately synthesize 4,5-bis-tert-butylphenanthrene, which may have …

Part I: Photochemical Generation Of Cyclohexyne From A Hydrocarbon Precursor Part Ii: A Triptycenyl Flower, Daniel Maurer

Honors Theses

Part I

Photolysis of phenanthrene-based methylenecyclopropane derivatives have previously been shown to generate alkylidenecarbenes, which readily rearrange to form alkynes. In this work, we show that photolysis of an analogous cyclic alkylidenecarbene precursor at ambi- ent temperature forms cyclohexyne via the putative cyclopentylidenecarbene, and can be trapped by dienes via a Diels-Alder reaction. Cyclohexyne and other strained cycloalkynes are of much interest to theoreticians and experimentalists alike. Results of coupled-cluster and DFT calculations on the potential energy surface of cyclopentylidenecarbene and the corresponding strained cyclohexyne are also presented. The photochemical generation of cy- clopentylidenecarbene, and thus cyclohexyne, from a hydrocarbon …

Experimental And Computational Study Of Methylphenylvinylidene And Its Rearrangements, Xi Yang

Honors Theses

In this study, the synthesis and properties were explored of the compound methylphenylvinylidene (MPV), a vinylidene carbene with methyl and phenyl groups as substituents. A phenanthrene-based precursor, 1-(1-phenylethylidene)-1a,9b-dihydro-1H-cyclopropa[l]phenanthrene, was synthesized in three steps and was subjected to photolysis in C₆D₆ at ambient temperature. During photolysis, the MPV carbene rearranged into 1-phenylpropyne via a 1,2-phenyl shift, instead of 1,2-methyl shift, confirmed by photolysis of ¹³C-labeled precursor. This experimental result is consistent with computational results using the CCSD(T)/cc-pVTZ//B3LYP/6-31+G* method. The calculations suggest that the 1,2-phenyl shift in singlet carbene requires 3.8 kcal/mol to overcome …

Structures And Nuclear Quadrupole Coupling Tensors Of 1,2-Dichloroethane, 1-Chloro-2-Fluoroethane And 2,3-Dichloropropene Studied Using Microwave Spectroscopy And Computational Chemistry, Asela Sampath Dikkumbura

Masters Theses

The Fourier-transform microwave (FTMW) spectra of 1,2-dichloroethane (12DCE), 1-chloro-2-fluoroethane (1C2FE) and 2,3-dichloropropene (23DCP) have been studied in the 6 to 18 GHz range to determine experimental rotational constants, nuclear quadrupole coupling constants (NQCC) and quartic centrifugal distortions constants. These three molecules have different spatial arrangements (anti and gauche) resulting from different relative orientations of chlorine and/or fluorine atoms about the C-C single bond. The lowest energy anti conformer of 12DCE is non-polar and it is not detectable by microwave spectroscopy, but rotational spectra of gauche-12DCE with three isotopologues, gauche-1C2FE with three isotopologues, and both anti- …

Theoretical Investigations Of Difluorobenzene Interacting With Ne And Infrared Analysis Of 1,1-Dichloroethylene From Synchrotron Data, Seri P. Kamari

Masters Theses

The intermolecular interactions between two molecules are of great importance in proteins, polypeptides, DNA binding, and drug binding interactions. Dimers of chemical rings such as difluorobenzene with hydrogen containing molecules such as acetylene (HCCH) and atoms such as neon are classic systems for investigating weak interactions; however, the microwave spectrum of 1,2-difluorobenzene...Ne does not behave as expected. Possible explanation of this phenomenon is that there is some large amplitude motion perturbing the spectrum.

A computational study was performed to analyze the potential energy surface (PES) of Ne or Ar with ortho, meta, and para difluorobenzene, and reveal the …

Synthesis And Characterization Of Dicopper(Ii) Complexes With Biological Relevance, Ashley E. Hall

Masters Theses

The research discussed in this study focused on the design, synthesis, and characterization of new model complexes that mimic the type-3 enzyme, catechol oxidase, which oxidizes catechols to their corresponding quinones. Our approach focused on the design and synthesis new model complexes that contain a dicopper(II) center that can be fine-tuned in a variety of ways, such as sterics and exogeneous bridging molecules. This method allows a multitude of complexes to be created and compared to determine how the overall structure affects the catecholase activity of the complexes.

Two ligands were synthesized; they contain a phenolate body, two amide groups, …

An In Vitro Study On The Effect Of Synthesized Tin (Iv) Complexes On Glioblastoma, Colorectal, And Skin Cancer Cell Lines, Jennie L. Williams, Lesley C. Lewis-Alleyne, Melinda Solomon, Long Nguyen, Robert Johnson, Jennifer Vital, Ping Ji, John Durant, Camille Cooper, Patrice Cagle, Patrick Martin, Don Vanderveer, William L. Jarrett, Alvin A. Holder

Chemistry & Biochemistry Faculty Publications

((E)-2-(2-hydroxybenzylideneamino)phenolato-2,2-diphenyl-6-aza-1,3-dioxa-2-stanna-[d,h]dibenzocyclononene, [Sn(Ph₂SB)] (compound 1, where Ph₂SB=(E)-2-(2-hydroxybenzylideneamino)phenolato Schiff base) and two novel compounds, [[SnPh2(F-azoSB)] (compound 2, where F-azoSB=4-((E)-(4-fluorophenyl)diazenyl)-2-((E)-(2-hydroxyphenylimino)methyl)phenolato Schiff base), [[SnPh2(sulf-azoSB)]0.125CHCl₃ (compound 3, where sulfamerazineazosalSB=4-((E)-(4-hydroxy-3-((E)-(2-hydroxyphenylimino)methyl)phenyl)diazenyl)-N-(4-methylpyrimidin-2-yl) benzenesulfonamide Schiff base), and the control compound, cisplatin (compound 4) were analysed to comparatively determine their effect on cancer cell growth. Anti-cancer properties of compounds 1-4 were examined using glioblastoma (U-1242 MG), colorectal (HT-29 and HCT-116), and skin (A431) human cancer cell lines. With regards to human glioblastoma cells, compounds 1 and 3 demonstrated anti-proliferative capacity in the cell line tested. Specifically, compounds 1 and 3 inhibited cell proliferation by 50% at …

Vanadium Toxicological Potential Versus Its Pharmacological Activity: New Developments And Research, Agnieszka Ścibior, Juan Llopis, Alvin A. Holder, Mario Altamirano-Lozano

Chemistry & Biochemistry Faculty Publications

Scibior, A., Llopis, J., Holder, A. A., & Altamirano-Lozano, M. (2016). Vanadium toxicological potential versus its pharmacological activity: New developments and research. Oxidative Medicine and Cellular Longevity, 2016, 1-2. doi: 10.1155/2016/7612347

Intercomparison And Evaluation Of Satellite Peroxyacetyl Nitrate Observations In The Upper Troposphere-Lower Stratosphere, Richard J. Pope, Nigel A. D. Richards, Martyn P. Chipperfield, David P. Moore, Sarah A. Monks, Stephen R. Arnold, Norbert Glatthor, Michael Kiefer, Tom J. Breider, Jeremy J. Harrison, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Peroxyacetyl nitrate (PAN) is an important chemical species in the troposphere as it aids the long-range transport of NO_x and subsequent formation of O₃ in relatively clean remote regions. Over the past few decades observations from aircraft campaigns and surface sites have been used to better understand the regional distribution of PAN. However, recent measurements made by satellites allow for a global assessment of PAN in the upper troposphere-lower stratosphere (UTLS). In this study, we investigate global PAN distributions from two independent retrieval methodologies, based on measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, on …

Drying Methods For The Fabrication Of Polymer Foam Material, Dalton Echard

Theses and Dissertations

This is a report on the study of the drying of nanoporous polymer foam material fabricated by photolithogtaphic methods. Three drying methods were employed, which were air drying, supercritical drying and freeze drying. After fabrication and drying, physical properties of the polymer foams were measured. These measurements included density of the material, Young’s modulus, surface area, and the shape of the skeletal particles. The measurements determined the effect of the polymer concentration and the effect of drying methods. It was determined that polymer concentration had a much larger effect on the properties of the materials than the drying method.

Electronic Structure And Stability Of Ligated Superatoms And Bimetallic Clusters, William H. Blades

Theses and Dissertations

Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms. The addition of ligands can tune the valence electron count and electron distribution in metal clusters. A combined experimental and theoretical study of the reactivity of methanol with Al_nI_m⁻ clusters reveals that ligands can enhance the stability of clusters. In some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. Also, an investigation is conducted to understand how the bonding …

Method Development Toward The Analysis Of The Functionalization Of Proteins, Victoria Calcote

Honors Theses

Calmodulin is a ubiquitous small intracellular protein that functions as a receptor for regulatory calcium signals and thus regulates a multitude of physiological processes in organisms as diverse as yeast, fruit flies, and mammals. Since its structure and function have been extensively studied, our goal is to create a calmodulin biomaterial, with the ultimate goal of in situ drug delivery or as a scaffold for stem cell growth and differentiation. We plan to create this biomaterial by using Click Chemistry, the rapid creation of new heteroatom bonds through a copper-catalyzed azide-alkyne cycloaddition. The bonds are created by treating calmodulin as …

Synthesis Of New Hexahydro-1h-Isoindole-1,3(2h)-Dione Derivatives From 2-Ethyl/Phenyl-3a,4,7,7a-Tetrahydro-1h-Isoindole-1,3-(2h)-Dione, Ayşe Tan, Bi̇rgül Koç, Nurhan Ki̇shali, Ertan Şahi̇n, Yunus Kara

Turkish Journal of Chemistry

A new and appropriate synthesis for hexahydro-1H-isoindole-1,3(2H)-dione derivatives has been developed starting from 3-sulfolene. The epoxidation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione and then the opening of the epoxide with nucleophiles gave hexahydro-1H-isoindole-1,3(2H)-dione derivatives. Amino and triazole derivatives of hexahydro-1H-isoindole-1,3(2H)-dione were synthesized from the formed product by the opening reaction of the epoxide with sodium azide. Hydroxyl analogues were obtained from cis-hydroxylation of 2-ethyl/phenyl-3a,4,7,7a-tetrahydro-1H-isoindole-1,3-(2H)-dione. The hydroxyl groups were converted to acetate.

An Indirect Model For Sintering Thermodynamics, Yüksel Sarikaya, Müşerref Önal

Turkish Journal of Chemistry

A model was proposed and used to calculated the changes in enthalpy $(\Delta H^{o})$, entropy $(\Delta S^{o}),$ and Gibbs energy $(\Delta G^{o})$, as well as equilibrium constant $(K)$ relating to the sintering of alumina compacts. Specific nanopore volume $(V)$ of the compacts was assumed as a thermodynamic variable. A hypothetical equilibrium constant $(K_{h})$ and corresponding Gibbs energy $(\Delta G_{h}^{o})$ were calculated depending on the $V$ value measured after each sintering. The thermodynamic relationships with the SI units were respectively evaluated for the initial-stage $(i)$ sintering between 1000 and 1200 $^{\circ}$C and final-stage $(f)$ sintering between 1200 and 1600 $^{\circ}$C in …

Remediation Of Cr(Vi) Via Combined Self-Reduction And Adsorption Bychemically Modified Carbon Sorbents, Mohamed E. Mahmoud, Amr. A. Yakout, Asmaa M. Halbas, Maher M. Osman

Turkish Journal of Chemistry

Hexavalent chromium, Cr(VI), is a highly toxic species, while trivalent chromium, Cr(III), is an essential trace element for humans and other organisms. In the present work, a simple, rapid, and efficient procedure for water treatment of Cr(VI) is described. Active carbon (AC) was chemically treated with HCl and NaOH for the formation of surface modified Acidic-AC and Basic-AC sorbents, respectively. In addition, AC sorbent was treated with HNO$_{3}$ as an oxidizing agent and sodium sulfite as a reducing agent for the formation of Ox-AC and Rd-AC sorbents, respectively. The modified AC sorbents were tested to identify their potential applications in …

Chromate Surface-Imprinted Silica Gel Sorbent For Speciation Of Cr In Surface Waters, Mariya Mitreva, Ivanka Dakova, Tanya Yordanova, Irina Karadjova

Turkish Journal of Chemistry

This study is focused on the synthesis of chromate anion imprinted sorbent supported on silica gel for nonchromatographic Cr speciation in surface waters. The preparation procedure is based on grafting of 3-methyl-1-trimethoxysilylpropylimidazolium, preliminarily coordinated to CrO$_{4}^{2-}$ as a template ion, onto the surface of silica gel. Sorption and desorption characteristics of surface-imprinted sorbent toward Cr(III) and Cr(VI) were examined by batch solid-phase extraction. An excellent separation of Cr(VI), selectively retained on the sorbent, from Cr(III) remained in the solution, was achieved at pH 2-3 for 20 min. A freshly prepared mixture of ascorbic acid and nitric acid was selected as …