Chemistry Commons^™

Silica Removal From Brine By Using Ion Exchange, Carlos R. Acevedo

Open Access Theses & Dissertations

Local governments have been forced to look for additional water sources to satisfy the ever increasing demand for fresh water. Very often, the new water sources such as the underground water in continental territories have high salt content. Currently, reverse osmosis technology (RO) is one of the most common processes for water desalination. However, this process is limited by high silica and salt concentrations in water. At high concentrations silica clogs the membranes used in the RO process, reducing their life and increasing operational costs. In this study, quaternary ammonium resins and sulfonic acid resins were used to remove silica …

Silver Doped Perfluoropolyether-Urethane Coatings: Antibacterial Activity And Surface Analysis, Niall Stobie, Brendan Duffy, Steven Hinder, Patrick Mchale, Declan Mccormack

Articles

The colonisation of clinical and industrial surfaces with pathogenic microorganisms has prompted increased research into the development of effective antibacterial and antifouling coatings. There is evidence that implanted biomedical surfaces coated with metallic silver can be inactivated by hysiological fluids, thus reducing the bioactivity of the coating. In this work, we report the biofilm inhibition of Staphylococcus epidermidis using a roomtemperatureprocessedsilver dopedperfluoropolyether-urethane coating. The release of silver ions from these fluoropolymers over a six-day period inhibited bacterial encrustation – as observed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) analysis indicated differences in carbon, fluorine and sodium surface composition …

Effect Of Organic Chelates On The Performance Of Hybrid Sol–Gel Coated Aa2024-T3 Aluminium Alloys, Rajath Varma, John Colreavy, John Cassidy, Mohamed Oubaha, Colette Mcdonagh, Brendan Duffy

Articles

Sol–gels are organic–inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol–gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis …

Charting The Late Cretaceous Seas: Mosasaur Richness And Morphological Diversification, Marcus R. Ross

Faculty Publications and Presentations

Abundant, readily identifiable, and biostratigraphically resolved specimens make mosasaurs ideal candidates to test fluxes in generic richness and morphological trends among marine vertebrates during the late Cretaceous. More than 1800 globally distributed mosasaur specimens are allocated to fifteen substage-level stratigraphically correlated assemblages. These data are quantitatively analyzed to illuminate trends within the group. Following their first appearance in the Cenomanian, mosasaurs experienced a significant radiation in the Coniacian and Santonian. Richness levels continued increasing into the Maastrichtian while mosasaurs incrementally exploited new predatory niches recognized via accumulation of novel dental morphologies. Their extinction at the end of the Cretaceous occurred …

An Aza-Cyclophane Stacked In Racemic Columnar Assemblies: Whole-Molecule Disorder In A Two-Dimensional Solid Solution, M Zeller

Chemistry: Faculty Publications and Other Works

The oxime derivative of [1.1.1]cyclophane cyclotriveratrylene (CTV) was ring expanded utilizing a Beckmann rearrangement to provide a ten-membered N-acetyl macrocyclic amide that crystallizes as a chloroform monosolvate in columnar assemblies manifesting an unusual disorder within the crystal. Columns made up of this structure consist of infinite columnar assemblies of alternating D and L enantiomers and therefore necessarily are made up of a racemate, yet the chiralities of individual molecules in adjacent columns are independent of one another, leading to the overall formation of a two-dimensional solid solution. The random arrangement of the columns within the structure leads to the …

Bromination Of Tetrachlorobenzobarrelene: Polyhalogenated Benzobicyclics, Mehmet Emi̇n Şengül, Demet Demi̇rci̇ Gülteki̇n, Selçuk Eşsi̇z, Ari̇f Daştan

Turkish Journal of Chemistry

The low and high temperature bromination reaction of tetrachlorobenzobarrelene was studied and the possible role of a neighboring group in rearrangements was investigated. New polyhalogenated benzobicyclic compounds were synthesized. All compounds were characterized properly using NMR spectroscopy.

Synthesis, Characterization, And Antibacterial Activity Of Some Transition Metals With The Schiff Base N-(2-Furanylmethylene)-3-Aminodibenzofuran, Aurora Reiss, Stelian Florea, Theodor Caproiu, Nicolae Stanica

Turkish Journal of Chemistry

This paper presents the structure and antibacterial properties of some complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) with a new Schiff base N-(2-furanylmethylene)-3- aminodibenzofuran. The structure of each complex was characterized by spectroscopic methods (IR, UV-Vis, ^1H-NMR, and ESR), conductometric and magnetic data, and thermogravimetric and elementary analysis. According to these data, we propose an octahedral geometry for Co(II), Ni(II), and Cu(II) complexes, and a tetrahedral geometry for Zn(II), Cd(II), and Hg(II) complexes. Antibacterial activity of the ligand and its complexes was tested against selected bacteria. The ligand and all the complexes possess antimicrobial activity, and antimicrobial activity …

Physical Properties Of Cytochromes C : 1. Role Of Cytochrome C' As A Nitric Oxide Carrier, 2. Folding Of Cytochrome C, Byunghoon Lee

Legacy Theses & Dissertations (2009 - 2024)

Cytochrome c’ binds and transfers endogenous NO in the denitrifying variant of Rhodobacter sphaeroides 2.4.3 and the NO bound ferrous heme that forms 5-coordinate resembles regulatory site in soluble guanylate cyclase. The Arg127 is close to the 5-coordiate NO bound heme of the cytochrome c’. The mutant (R127A) that was overexpressed in a cytochrome c’ knock-out R. sphaeroides 2.4.3 provided the opportunity to research the functional role of Arg127 in the redox potential and NO binding. The mutant (R127A) showed lower redox potential and lower NO binding free energy than wild type. ERP and ENDOR showed that the mutant had …

Raman Spectroscopy Of Body Fluids : A Nondestructive Identification Technique For Forensic Applications, Kelly Virkler

Legacy Theses & Dissertations (2009 - 2024)

The analysis of body fluid evidence during forensic investigations is a complicated process, yet it is a critical step in determining the key facts of a crime. There is no doubt that DNA analysis is an extremely useful tool that can identify a suspect or victim, but crime scene investigators must first locate and identify potential body fluid stains that can be collected for DNA analysis. Current screening tests are destructive to the sample and can give false positive results, so a nondestructive technique such as Raman spectroscopy, that can possibly confirm the presence of a particular fluid, could lend …

Bowl-Shaped Polyaromatic Hydrocarbons (Buckybowls) : Crystal Packing And Metal Binding Reactions, Alexander S. Filatov

Legacy Theses & Dissertations (2009 - 2024)

This work is a part of a broad program in our laboratory dedicated to the investigation of a new class of non-planar polyaromatic hydrocarbons that map onto the surfaces of fullerenes (and referred to as buckybowls). It focuses on the preparation of buckybowls, their molecular and solid state structures, and reactivity in metal binding reactions. For the first time, the structures of all available buckybowls have been analyzed using X-ray diffraction data collected in the course of this work, as well as data previously obtained in our group or reported by others (and dearchived from the Cambridge Structural Database). Forces …

Nanocomposite Thin Films Of Au Nanoparticles Embedded In Yttria-Stabilized Zirconia For Plasmonic-Based Harsh Environment Gas Detection, Phillip Henry Rogers

Legacy Theses & Dissertations (2009 - 2024)

Increased health concerns due to the emission of gases linked to the production of tropospheric ozone by petroleum based fuel burning engines has resulted in the codification of more stringent emissions regulations domestically. Emissions regulations on commercial jetliners are one of the areas to be met with stricter standards. Currently there is not a sensing technology that can detect the emissions gases in the exhaust stream of a jet turbine engine with lower detection limits that meet these standards.

Genetically Engineered Repetitive Polypeptides : Design, Synthesis, Characterization, And Applications, Natalya I. Topilina

Legacy Theses & Dissertations (2009 - 2024)

This work is dedicated to the investigation of protein folding with the emphasis on the aggregation and amyloid fibrils formation. The focus of the research is to elucidate the relationship between polypeptide chain sequence and folding/aggregation properties. For this purpose, i) libraries of the de novo macromolecular repetitive β-sheet forming polypeptides were designed, and ii) the strategy for their rapid creation was developed. The strategy enables retention of a basic polypeptide core, yet allowing variations in the repetitive sequence, degree of polymerization and distribution of specific amino acids. The polypeptides were expressed in E. coli, purified, and characterized by various …

Measurement Of Atmospheric Ammonia Species : Development, Validation, And Field Applications Of An Analytical Method, Jian Hou

Legacy Theses & Dissertations (2009 - 2024)

Ammonia is the primary base in the atmosphere. It reacts readily with atmospheric acids such as sulfuric acid, nitric acid, and hydrochloric acid to form ammonium salts that occur predominantly in the fine aerosol particle (PM2.5) fraction. The ability to measure ammonia species (NHx, the sum of gaseous NH₃ and particulate NH₄+) is essential for the investigation of atmospheric behaviors of NHx. In this dissertation work, a highly sensitive technique has been developed for the measurement of atmospheric NHx species. The method is based on aqueous scrubbing of the atmospheric NH₃ and NH₄+ using …

Biomonitoring For Exposure To Trace Elements In Utero : Analysis Of The Human Placenta, Pamela Catherine Kruger

Legacy Theses & Dissertations (2009 - 2024)

The placenta forms in eutherian mammals, and is responsible for the nutrition of the developing fetus. However, maternal exposure to environmental pollutants both before and during pregnancy may result in the passage of toxins through the placental barrier and into fetal tissues. The placenta is the only organ derived from both maternal and fetal tissues, and establishes a link between the fetus and the environmental exposures of the mother. The analysis of placentae for the presence of environmental pollutants offers the possibility of exposure measurements in both the mother and the developing fetus. Specifically, trace element determination in human placentae …

Synthesis And Evaluation Of Some Steroidal Oximes As Cytotoxic Agents: Structure/Activity Studies (I), Jianguo Cui, Lei Fan, Li Liang Huang, Hong Li Liu, Aimin Zhou

Chemistry Faculty Publications

The side chain of a compound plays an important role in its biological function. In our studies, we have found that hydroximinosteroid derivatives with different side chains and position of hydroximino on ring A and B displayed remarkable distinct cytotoxicities against a diversity of cancer cell types. Presence of an oxime group on ring B and a hydroxy on ring A or B resulted in a higher cytotoxicity than other structural motifs. In addition, a cholesterol-type side chain at position 17 was required for the biological activity. Our findings provide new evidence showing the relationship between the chemical structure and …

Energy Decomposition Analysis Of Covalent Bonds And Intermolecular Interactions, Peifeng Su, Hui Li

Department of Chemistry: Faculty Publications

An energy decomposition analysis method is implemented for the analysis of both covalent bonds and intermolecular interactions on the basis of single-determinant Hartree–Fock (HF) (restricted closed shell HF, restricted open shell HF, and unrestricted open shell HF) wavefunctions and their density functional theory analogs. For HF methods, the total interaction energy from a supermolecule calculation is decomposed into electrostatic, exchange, repulsion, and polarization terms. Dispersion energy is obtained from second-order Møller–Plesset perturbation theory and coupled-cluster methods such as CCSD and CCSD(T). Similar to the HF methods, Kohn–Sham density functional interaction energy is decomposed into electrostatic, exchange, repulsion, polarization, and dispersion …

Immobilization Method For Producing Active Α1-Acid Glycoprotein, David S. Hage, Hai Xuan

Department of Chemistry: Faculty Publications

A method and kit for immobilization of a glycoprotein. The method may include activating an affinity Support. The affinity Support may be activated by reacting the affinity Support with a compound that is reactive with one or more functional groups included within the glycoprotein. The method may also include oxidizing the glycoprotein in which oxidation conditions are selected to yield an oxidized glycoprotein that is biologically active and contains a Sufficient number of reactive aldehyde groups for coupling to a Support. For example, the oxidized glycoprotein may include five reactive aldehyde groups. In addition, the method may include reacting the …

Heterogeneous Conductorlike Solvation Model, Hui Li, Dejun Si

Department of Chemistry: Faculty Publications

A heterogeneous conductorlike solvation model (conductorlike screening model/conductorlike polarizable continuum model) that uses different local effective dielectrics for different portions of the solute cavity surface is implemented for quantum chemical Hartree–Fock and Kohn–Sham methods. A variational treatment is used to form the heterogeneous solvation operator, so a simple analytic expression of the energy gradients, which are vital for geometry optimization and molecular dynamics simulation, is derived and implemented. Using the new Fixed Points with Variable Areas surface tessellation scheme, continuous and smooth potential energy surfaces as well as analytic gradients are obtained for this heterogeneous model.

Techniques For Consecutive Tem And Atom Probe Tomography Analysis Of Nanowires, D. R. Diercks, B. P. Gorman, Chin Li Cheung, G. Wang

Department of Chemistry: Faculty Publications

Nanowires show great promise for development in many technological applications including electronics, photonics, and displays . Due to the fine scale of nanowires, transmission electron microscopy (TEM) and atom probe tomography (APT) are among a limited number of techniques that can measure the crystallographic and chemical nature of these structures which ultimately define their performance.

Direct Binding Of Cytosolic Ndp Kinases To Membrane Lipids Is Regulated By Nucleotides, Kimberly A. P. Mitchell, Gabor Szabo, Angela De S . Otero

Faculty Publications and Presentations

In spite of their complete lack of any structural features that characterize membrane proteins, cytosolic nucleoside-diphosphate kinases (NDPKs) have been found repeatedly to associate with membranes. In some instances the recruitment of cytosolic NDPKs to membranes was attributed to interactions with peripheral or integral membrane proteins, but in many cases the mechanism underlying the association of NDPKs with membranes remained unknown. We show here that cytosolic NDPKs bind directly to membrane lipids in a dynamic process that is controlled by its substrates, nucleoside tri- and diphosphates, and can be fully reconstituted with chemically defined, protein-free phospholipids and recombinant NDPK, or …

Methods For The Isolation Of Sensory And Primary Cilia—An Overview, Kimberly A. P. Mitchell, Gabor Szabo, Angela De S. Otero

Faculty Publications and Presentations

Detailed proteomic analyses of mammalian olfactory and rod photoreceptor sensory cilia are now available, providing an inventory of resident ciliary proteins and laying the foundation for future studies of developmental and spatio-temporal changes in the composition of sensory cilia. Cilia purification methods that were elaborated and perfected over several decades were essential for these advances. In contrast, the proteome of primary cilia is yet to be established, because purification procedures for this organelle have been developed only recently. In this chapter we review current techniques for the purification of olfactory and photoreceptor cilia, and evaluate methods designed for the selective …

Development Of New Chiral Selectors For Liquid Chromatography And Their Performance Relative To Established Chiral Stationary Phases (Csps), Ping Sun

Chemistry & Biochemistry Dissertations - Archive

HPLC with chiral stationary phases (CSPs) has proven to be the most widely applicable and versatile technique for enantiomeric separations. This dissertation discusses new research in three important areas of enantiomeric separations: HPLC method developments for target chiral analytes using the existing CSPs, mechanistic investigations by NMR, and development of new HPLC CSPs. Two classes of commercial chiral stationary phases (cyclodextrin-type and macrocyclic glycopeptide-type) were evaluated by separating specific groups of chiral analytes, including β-lactam compounds and ruthenium(II) polypyridyl complexes. The effects of chiral selector structures, mobile phase compositions, and analyte structures have been examined. For Ru(II) complexes, the newly …

Task Specific Ionic Liquids For Enantiomeric Recognition And Nanomaterials For Biomedical Imaging, David Kipkogei Bwambok

LSU Doctoral Dissertations

Ionic liquids (ILs) are organic salts that melt at or below 100°C. Interest in ILs continues to grow due to their unique properties such as lack of measurable vapor pressure, high thermal stability, tunability and recyclability. The first part of this dissertation explores the use of chiral ionic liquids (CILs) for enantiomeric recognition of chiral analytes using fluorescence spectroscopy. Chiral analyses continue to be a subject of considerable interest primarily as a result of legislation introduced by the Food and Drug Administration. This has led to an increased need for suitable chiral selectors and methods to verify the enantiomeric forms …

Stain Etching With Fe(Iii), V(V), And Ce(Iv) To Form Microporous Silicon, M E. Dudley, Kurt Kolasinski

Chemistry Faculty Publications

Stain etchants made from (HF+V(2)O(5)) or (HF+FeCl(3)center dot 6H(2)O+HCl or H(2)SO(4)) exhibited virtually no initiation time before the formation of porous silicon. Etching with Fe(III) solutions for extended periods resulted in a unique dual layer structure that can reach a thickness >10 mu m and exhibited not only red-orange but also green photoluminescence (PL). Etching with (CeF(4)+H(2)SO(4)) produced extremely uniform films. Visible PL was observed immediately after etching except for those films produced with (CeF(4)+H(2)SO(4)), which required several days of air exposure before bright and robust PL developed.

Etching Of Silicon In Fluoride Solutions, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Sustainability: Energy & Global Chemistry, Kurt W. Kolasinski

Chemistry Faculty Publications

No abstract provided.

Gold Nanoparticles: Synthesis, Property Study And Applcications For Biomolecular Detection And Photothermal Therapy, Xiong Liu

Electronic Theses and Dissertations

This dissertation presents a systematic study on gold nanoparticles: from their chemical synthesis, modification of surface functionalities, optical properties studies with emphasis on the absorption and scattering properties, to applications of gold nanoparticles in biomolecular detection, imaging and photothermal therapy. In chapter 2, we studied the kinetics of gold nanoparticle growth under Brust-Shiffrin reaction conditions. In chapter 3, we further examined the reaction mechanism and growth kinetics of gold nanoparticles using oleylamine as both a reducing reagent and particle growth passivation ligand. From these two projects, important understanding was revealed on gold nanoparticle formation and growth mechanism. Chapter 4 describes …

Imaging And Spectroscopy Of Conducting Polymer-Fullerene Composite Materials, Daeri Tenery

Electronic Theses and Dissertations

Since the development and optical study of conjugated (conducting) polymers it has become apparent that chain conformation and aggregation at the molecular scale result in complex heterogeneous nanostructured bulk materials for which a detailed insight into morphological, spectroscopic as well as optoelectronic properties and mechanisms is overwhelmingly difficult to obtain. Nanoparticles composed of the conjugated polymer poly (MEH-PPV) and nanocomposite nanoparticles consisting of MEH-PPV doped with 1-(3-methoxycarbonylpropyl)-1-phenyl-C61 (PCBM) were prepared as model systems to study these materials at the length scale of one to a few domains. The MEH-PPV and PCBM doped nanoparticles were analyzed by single imaging/particle spectroscopy (SPS) …

Synthesis Of Novel Fluorene-Based Two-Photon Absorbing Molecules And Their Applications In Optical Data Storage, Microfabricatio, Ciceron Yanez

Electronic Theses and Dissertations

Two-photon absorption (2PA) has been used for a number of scientific and technological applications, exploiting the fact that the 2PA probability is directly proportional to the square of the incident light intensity (while one-photon absorption bears a linear relation to the incident light intensity). This intrinsic property of 2PA leads to 3D spatial localization, important in fields such as optical data storage, fluorescence microscopy, and 3D microfabrication. The spatial confinement that 2PA enables has been used to induce photochemical and photophysical events in increasingly smaller volumes and allowed nonlinear, 2PA-based, technologies to reach sub-diffraction limit resolutions. The primary focus of …

Arrow Pushing In Organic Chemistry: An Easy Approach To Understanding Reaction Mechanisms (Book Review), Jeffrey H. Glans

Chemistry & Physics Faculty Publications

A book review by Jeffrey Glans.

Levy, Daniel E. Arrow Pushing in Organic Chemistry: An Easy Approach to Understanding Reaction Mechanisms. New York: Wiley, 2008.

ISBN 9780470171103