Chemistry Commons^™

Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake

Theses and Dissertations--Plant and Soil Sciences

In order to properly evaluate the ecological and human health risks of ZnO Manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in the wastewater treatment process and in soils receiving biosolids. To address this critical knowledge gap, we examined the transformation reactions of 30 nm ZnO MNMs in single component and multi-component systems, with phosphate and natural organic matter (NOM). We also assessed the influence of nano ZnO transformation on the bioavailability, and toxicity of ZnO transformation products to Triticum aestivum. The data revealed that ZnO MNMs react with phosphate at …

Preparation And Characterization Of Palladium Catalysts, Michael J. Anderson

Theses and Dissertations

There is a critical need for improved combustion-oxidation catalysts to reduce emissions of toxic volatile organic compounds (VOCs) emitted from exhaust gas of gasoline combustion in automotive vehicles. Materials and systems currently available, such as the three way catalytic converter (TWC), have low activity below 400 °C in the catalytic process. Palladium catalysts were prepared by alternative methods including: preparation by wet impregnation or incipient wetness, drying by room temperature or air-oven, and support choice between silica and alumina. These catalysts were prepared to meet the demand for low temperature oxidation. Results indicated a 5% increase in percent dispersion of …

"Molecular Spectroscopy And Dynamics Of Reactive Chemical Intermediates Studied Using Laser Induced Fluorescence (Lif), Single Vibronic Level (Svl) Emission And Resonance Enhanced Multiphoton Ionization (Rempi) Spectrometry.", Lloyd Godfrey Muzangwa

Dissertations (1934 -)

ABSTRACT

"MOLECULAR SPECTROSCOPY AND DYNAMICS OF REACTIVE CHEMICAL INTERMEDIATES STUDIED USING LASER INDUCED FLUORESCENCE (LIF), SINGLE VIBRONIC LEVEL (SVL) EMISSION AND RESONANCE ENHANCED MULTIPHOTON IONIZATION (REMPI) SPECTROMETRY"

Lloyd Muzangwa, B.Sc. (Hons, Biochemistry).

Marquette University, 2013

In the studies of complex chemical processes, it is necessary to postulate mechanisms involving transient intermediates such as radicals, ions, and pre-reactive complexes. The detection and characterization of these intermediates affords in ideal cases determination of the detailed chemical mechanism, which, in turn, can permit the development of rational strategies for removing undesired products and enhancing the yield of the desired species. This dissertation describes …

Matrix-Isolation And Computational Studies Of Transient Polyhalogenated Intermediates And Weakly-Bound Complexes., Aimable Kalume

Dissertations (1934 -)

As time goes by and new innovations are brought up to improve living conditions, the human impact on the environment becomes more significant. It has been shown that man-made halogenated compounds play a key role in many real-world chemical processes. For example, in combustion, these compounds are used as fire retardant agents, and in atmospheric chemistry, they initiate ozone depletion reactions.

However little is known about the mechanisms governing these processes and many intermediates involved in these processes have been elusive to researchers for diverse reasons such as short lifetime and difficulty in distinguishing products from parents molecules. The studies …

Molecular Tweezers: Studies Directed Towards The Preparation Of Effective Charge Transport Materials, Khushabu Thakur

Dissertations (1934 -)

ABSTRACT

MOLECULAR TWEEZERS: STUDIES DIRECTED TOWARDS THE PREPARATION OF EFFECTIVE CHARGE TRANSPORT MATERIALS

Khushabu Thakur, B.Sc, M.Sc.

Marquette University, 2013

An important focus of the modern areas of photovoltaics and molecular electronics is to identify molecules or molecular assemblies that can promote effective charge/exciton transport over long distances. In order to be able to exert control and establish necessary structural parameters for reproducible production of self-assembled structures for long-distance charge transport, our laboratory has been actively engaged towards the preparation of a variety of well-defined, cofacially-arrayed polybenzenoid nanostructures in which aromatic donors are cofacially stacked.

Herein, we undertake the design …

Early Transition Metal Ccc-Nhc Pincer Complexes: Synthesis, Characterization, And Catalysis, Theodore Rudy Helgert

Electronic Theses and Dissertations

The previously reported amine elimination methodology for the metalation of CCC-NHC pincer ligand precursors has been extended to other early-transition metals and ligands. Specifically, synthetic results for the preparation of imidazole based CCC-NHC pincer Ti (IV), CCC-NHC pincer Ta (V) will be discussed. In addition, the synthesis of a new triazole based CCC-NHC pincer ligand precursor and its metalation with Ta (V) will be presented. Coordination sphere manipulation of the new pincer complexes using TMSCl for the Ti complex and lithium t-butylamide for the Ta complexes is also discussed. The reaction of the initial Ta CCC-NHC complex with lithium t-butylamide …

Qualitative And Quantitative Analysis Of Lignocellulosic Biomass Using Infrared Techniques: A Mini-Review, Feng Xu, Jianming Yu, Tesfaye Tesso, Floyd Dowell, Donghai Wang

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Current wet chemical methods for biomass composition analysis using two-step sulfuric acid hydrolysis are time-consuming, labor-intensive, and unable to provide structural information about biomass. Infrared techniques provide fast, low-cost analysis, are non-destructive, and have shown promising results. Chemometric analysis has allowed researchers to perform qualitative and quantitative study of biomass with both near-infrared and mid-infrared spectroscopy. This review summarizes the progress and applications of infrared techniques in biomass study, and compares the infrared and the wet chemical methods for composition analysis. In addition to reviewing recent studies of biomass structure and composition, we also discuss the progress and prospects for …

Single-Stranded Dna Scanning And Deamination With Single-Molecule Resolution, Padhuk Gamarala Senavirathne

Wayne State University Dissertations

SINGLE-STRANDED DNA SCANNING AND DEAMINATION WITH SINGLE-MOLECULE RESOLUTION

by

GAYAN SENAVIRATHNE

December 2013

Advisor: Dr. David Rueda & Dr.Ashok Bhagwat

Major: Chemistry (Analytical)

Degree: Doctor of Philosophy

APOBEC3G (Apo3G) and Activation-Induced cytidine Deaminase (AID) are the most notable members of APOBEC enzymes, a family of cytidine (C) deaminases with crucial functions in the immune system. In T cells, Apo3G deaminates C in viral cDNA to halt the replication of HIV 1 strains lacking viral infectivity factor (vif). In B cells, AID is required for the diversification of antibodies through initiation of somatic hypermutation (SHM), and class switch recombination (CSR), by …

Method Development Using Laser Ablation And Solution Icpms And Their Application In Environmental Science And Forensic Provenance Studies, Kaixuan Bu

Electronic Theses and Dissertations

Inductively coupled plasma mass spectrometry (ICPMS) is an analytical technique that can be used to determine multiple elements and isotope ratios in a wide variety of samples. In this work, four projects are described that involve the method development using laser ablation (LA) and solution-based ICPMS and their application in environmental science and forensic (provenance) investigations. In the first project, plutonium (Pu) concentrations and 240Pu/ 239Pu atom ratios were measured in kelp, lichen, aquatic moss, and horse mussel collected on or near Amchitka Island, a former nuclear test in Alaska, and at a background site. The Pu in terrestrial and …

Specific Salt Effects On The Formation And Thermal Transitions Among Β-Lactoglobulin And Pectin Electrostatic Complexes, Stacey Ann Hirt

Open Access Theses

Factors of ion specificity and ionic strength (I~0-100) were studied in the electrostatic complex formation and protein particle formation by thermal treatment for a β-lactoglobulin and pectin system. ζ-potential showed β-lactoglobulin and pectin began to interact near pH 5.50 and interactions were strengthened with decrease in pH. Visible light turbidimetry and light scattering at 90° revealed a trend in critical pH transitions for electrostatic complex formation based on both the ionic strength and the anion of the salt species, while effects of the monovalent cation was insignificant. Critical pH values for complex formation and separation (pHc and pHΦ) decreased with …

The Design And Synthesis Of Peptidomimetic Serine-Based Prodrugs As 14-3-3 Inhibitors, Eric Drake Jones

Open Access Theses

Jones, Eric D. Masters of Science, Purdue University, October 2013. THE DESIGN AND SYNTHESIS OF PEPTIDOMEMETIC SERINE-BASED PRODRUGS AS 14-3-3 INHIBITORS. Major Professor: Richard Borch

This work describes the design and synthesis of peptidomimetics for the inhibition of the protein-protein interactions (PPI) with 14-3-3. This protein is a promiscuous binder of other proteins with a variety of key functions such as the regulation of proapoptotic proteins (e.g. FOXO, BAD), suppression of tumor growth, and sensitizing cells to other drugs. The promiscuous binding is the result of PPIs being shallow binding sites which accept many proteins and modify their activity. Compounds …

Pickering Stabilization Of Oil-Water Interfaces By Heated B-Lactoglobulin/Pectin Particles, Laura Kathryn Zimmerer

Open Access Theses

The use of natural biopolymer particles as Pickering stabilizers for oil-in-water emulsions was investigated. B-lactoglobulin microgels and B-lactoglobulin/pectin complexes were created by heating appropriate biopolymer solutions at pH 5.8 and 4.75, respectively. Resultant particles exhibited spherical morphology with diameters of 100-300 nm and possessed significant negative surface charge. Particles were first homogenized with 1% corn oil at 0.05%, 0.1% or 0.25% (wt/ wt) particle concentrations. All emulsions appeared stable over seven days with only a thin, creamed ring forming after several hours. Corn oil emulsions were most stable with 0.25% heated complexes, with volume-weighted mean droplet diameter remaining around 480 …

Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr

Open Access Dissertations

The shift to concentrated animal production facilities and increasing rural-urban migration has increased the localized land application of nearly 1 billion tons of manure and biosolids annually. Although these applications provide nutrients and contribute to soil tilth, they also serve as a source for an estimated 49 tons of the natural manure-borne estrogens, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), and estrone (E1). While these estrogens are critical to endocrine systems, the low concentrations observed in the environment can disrupt endocrine function in non-target organisms, e.g., altering secondary sex characteristics which can lead to changes in wildlife communities.

Research presented here focuses on …

Growth And Polymer Synthesis Of Pseudomonas Oleovorans With The Incorporation Of Nonaoic Acid, Brittany Black

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Probing The Disulfide Structure Of Scytovirin, Adam Powell

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Development Of A Screening Protocol Of Antiprotozoal Activity Against Acanthameoba Castellanii, Chelsey Stewart

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Preliminary Studies Of The N-Terminal Of Scytovirin, Thomas Swain

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Yeast Eif4b Binds To The Head Of The 40s Ribosomal Subunit And Promotes Mrna Recruitment Through Its N-Terminal And Internal Repeat Domains, Sarah F. Mitchell

Chemistry and Biochemistry Faculty Works

Eukaryotic translation initiation factor (eIF)4B stimulates recruitment of mRNA to the 43S ribosomal pre-initiation complex (PIC). Yeast eIF4B (yeIF4B), shown previously to bind single-stranded (ss) RNA, consists of an N-terminal domain (NTD), predicted to be unstructured in solution; an RNA-recognition motif (RRM); an unusual domain comprised of seven imperfect repeats of 26 amino acids; and a C-terminal domain. Although the mechanism of yeIF4B action has remained obscure, most models have suggested central roles for its RRM and ssRNA-binding activity. We have dissected the functions of yeIF4B's domains and show that the RRM and its ssRNA-binding activity are dispensable in vitro …

Hiv-1 Frameshift Efficiency Is Primarily Determined By The Stability Of Base Pairs Positioned At The Mrna Entrance Channel Of The Ribosome, Kathryn Mouzakis

Chemistry and Biochemistry Faculty Works

The human immunodeficiency virus (HIV) requires a programmed -1 ribosomal frameshift for Pol gene expression. The HIV frameshift site consists of a heptanucleotide slippery sequence (UUUUUUA) followed by a spacer region and a downstream RNA stem-loop structure. Here we investigate the role of the RNA structure in promoting the -1 frameshift. The stem-loop was systematically altered to decouple the contributions of local and overall thermodynamic stability towards frameshift efficiency. No correlation between overall stability and frameshift efficiency is observed. In contrast, there is a strong correlation between frameshift efficiency and the local thermodynamic stability of the first 3-4 bp in …

Do We Need To Analyze Spectra By Hand?, Adam M. Terwilliger, Richard L. Lord

Student Summer Scholars Manuscripts

Computational chemistry uses computer science to explore structures and energies of chemical species. A typical computational chemistry output file contains tens or hundreds of thousands of text lines. Automation makes the analysis of these large data sets increasingly more efficient. In turn, we constructed computer programs using Python that allow us to focus our time upon the chemical interpretation of these results. We used these efficient analyses to study a vanadiumoxo species synthesized by our collaborators. Our calculations answer many questions about the redox states in these compounds, though they predict that the experimental crystal structure may not reveal all …

Ph Dependent Proteolysis Of Neural Cadherin, Candice Ashton Walters

Honors Theses

Cadherins are the primary calcium-dependent cell-cell adhesion molecule and are essential to vertebrates. They ensure the integrity of epithelial barriers that allow for maintenance of homeostasis in humans and protection against invading microorganisms. A common invader capable of forging past this line of defense is the fungus Candida albicans. The main virulence mechanism of C. alibans in acidic environments is its secreted aspartyl proteinases (SAPs), which are hydrolytic enzymes that degrade cadherin-mediated cell adhesion leading to infection of the underlying tissues. Cadherin is normally resistant to cleavage by proteases due to stabilization of the protein structure by bound calcium and …

Effect Of Sample History On Dissolution Rates Of Gypsum {010} Surfaces, Dennis Stefan Renier Lennaerts

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Mineral dissolution plays a significant role in geochemical processes such as carbon sequestration and isotope geochemistry. While factors such as temperature, pressure, and solution chemistry have been widely studied, the effects of sample history and surface morphology on dissolution rates have been studied to a lesser extent. This research focuses on the dissolution of cleaved, polished, and reacted samples of the atomically flat natural {010} cleavage plane of gypsum (CaSO4·2H2O) to further investigate upon the effect of sample history. Gypsum was chosen as the mineral of interest because of its planar crystal surface and relatively fast dissolution rate. Chemical dissolution …

Effect Of Sample Miscut On Dissolution Kinetics Of Calcite (104) Cleavage Surfaces, Tahiru Sulley Addo

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Calcite is one of the most abundant naturally occurring carbonate minerals in the earth crust, and it is believe to play a crucial role in the long-term effectiveness of geochemical process works such as geological carbon sequestration. Due to the ease in which clean, flat calcite surfaces may be prepared, a lot of dissolution studies have been carried out on its (104) cleavage plane. However in geologic media, natural calcite grains consist of alternate surface terminations that do not display similar crystallographic properties as the (104) cleavage plane. This study focuses on the effect of miscut and step orientation on …

Libraries From Libraries Approach To The Synthesis Of Arylidene Oxindoles, Kyle James Knisley

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A libraries from libraries combinatorial chemistry approach was employed to synthesize fluorinated derivatives of both oxindoles and isatins as potential pharmaceuticals or targeting agents for imaging purposes related to cancer or Alzheimer's disease. Synthesis for these fluorinated derivatives are described by routes involving, either: a) N-alkylation of 5-substituted isatins followed by Wolff-Kishner reduction to the corresponding oxindoles and final Knoevenagel condensation with aryl aldehydes, or; b) Wolff-Kishner reduction of the isatins followed by condensation and finishing with the N-alkylation of the aldol products. In specific cases, a click reaction followed the N-alkylation of the aldol products to form the isatin …

The Synthesis Of Haplomyrtin Utilizing The Triisopropylsilyl Protecting Group, William S. Barrow

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The synthesis of the arylnaphthalene lignan haplomyrtin using vanillin as a starting material is synthesized via: 1) a bromination of vanillin, 4-hydroxy-5-methoxybenzaldehyde, to produce 6-bromovanillin 2) a hydroxyl protection step of 6-bromovanillin with triisopropylsilylchloride to produce 2-bromo-4-triisopropylsilyoxy-5-methoxybenzaldehyde 3) an aldehyde protection step through a cyclic acetal formation using ethylene glycol to produce 2-(2-bromo-4-triisopropylsilyloxy-5-methoxyphenyl)-1,3-dioxolane 4) a lithium for halogen exchange of the doubly protected 6-bromovanillin leads to neucleophilic coupling with piperonal producing 1,3-benzodioxol-5-yl-[5-triisopropylsilyloxy-2-(1,3-dioxolane-2-yl)-4-methoxyphenyl]methanol and 5) an acid catalyzed intramolecular cycloaddition /Diels Alder adduct with dimethyl acetylenedicarboxylate producing dimethyl 1-(1,3-benzodioxol-5-yl)-4-hydroxy-6-methoxy-7-triisopropylsilyloxynaphthalene-2,3-dicarboxylate.

Iodo Containing Sulfone And Sulfonamide Based Poly(Arylene Ether)S, Fadwa G. Constandinidis

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In an ongoing project involving the synthesis of functionalized poly(arylene ether)s that carry pendent phenyl sulfonyl groups, the introduction of an iodo group was desired. The effects of fluorine position on the electrophilic iodination of the 2,4-, 2,6-, and 2,5- and 3,5-isomers of difluorodiphenylsulfone, DFDPS were studied. The relative reactivity, toward EAS, was probed via ¹³C NMR spectroscopy and verified experimentally by iodination with N-iodosuccinimide. The product mixtures and corresponding structures indicated that intermediate stability did not always correlate to reactivity. Model studies were also conducted on DFDPS isomers that successfully carry in iodo groups in a pendent …

The Synthesis Of Benzyloxy Substituted Dp-Ppvs, Ryan Oostendorp

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The alkyne 1-(benzyloxy)-4-(propargyloxy)benzene was reacted with 2,5-di(carboethoxy)3,4-diphenylcyclopentadienone to yield diethyl 5-((4-(benzyloxy)phenoxy)methyl)-2,3-diphenylterephthalate. The terephthalate was reduced with lithium aluminum hydride to produce 5-((4-(benzyloxy)phenoxy)methyl)-1,4-di(hydroxymethyl)-2,3-diphenylbenzene. The diol was reacted with thionyl chloride to yield the monomer 5-((4-(benzyloxy)phenoxy)methyl)-1,4-di(chloromethyl)-2,3-diphenylbenzene that has a pendent protected phenol function. The new compounds were characterized by melting point, IR, 1H NMR, 13C NMR spectroscopy and elemental analysis. Polymerization of the dichloro monomer via a Gilch polymerization yielded poly[(2,3-diphenyl-(5-((4-(benzyloxy)phenoxy)methyl)-1,4-phenylene) vinylene]. The polymer was characterized by IR, 1H NMR spectroscopy, TGA and DSC. The polymer was insoluble in most solvents but partially soluble in chlorinated solvents. The solid polymer fluoresced a …

Synthesis And Electrodeposition Of Mixed Metal Trinuclear Clusters Of Molybdenum And Chromium In Ionic Liquid Onto A Platinum Electrode, Lynn Renee Frock

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Electrochemical properties of [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 and [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3] in 1-ethyl-3-methylimidazolium bis(pentafluoroethanesulfonyl)-imide ionic liquid was investigated. Cyclic voltammograms using a Platinum electrode indicated deposition had occurred for the [Mo3O2(O2CCH3)6(H2O)(CF3SO2H)2 metal cluster but had not for the polynuclear complex [Cr2Mo(u2-CH3COO)6(u3-O)(H2O)3][CF3SO3]. Constant potential electrolysis of -1.23 V using a platinum foil electrode was performed. Scanning electron microscopy in combination with energy dispersion spectroscopy confirmed that deposition had occurred.

The Solvent-Free Synthesis Of And N-Methyl-N-Alkylpiperidinium Salts And Their Anion Exchange Reactions With Dilithium Phthalocyanine, Michael Joseph Krol Jr.

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A nucleophilic substitution reaction of N-methylpiperidine with bromopropane, bromobutane, bromopentane, bromohexane and bromoheptane was carried out in a Q-Tube with excess alkyl halide and yielded N-methyl-N-propylpiperidinium bromide, N-methyl-N-butylpiperidinium bromide, N-methyl-N-pentylpiperidinium bromide, N-methyl-N-hexylpiperidinium bromide and N-methyl-N-heptylpiperidinium bromide in yields from 85 to 92 %. The salts, which were solids at room temperature, were soluble in dichloromethane and were characterized by 1H and 13C NMR, elemental analysis and DSC. Two of the piperidinium bromides, N-methyl-N-propylpiperidinium bromide, N-methyl-N-butylpiperidinium bromide were used in an anion exchange reaction with dilithium phthlocyanine to yield N-methyl-N-propylpiperidinium lithium phthalocyanine and N-methyl-N-butylpiperidinium lithium phthalocyanine, respectively in 78 to 85% …

Dual-Stimuli Responsive Poly(Ethylenimine)S With A Tunable Lcst For Gene Delivery, Mary Abraham

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Hyperbranched poly(ethylenimine)s (HPEI) were modified with hydrophobic isobutyryl amide groups (HPEI-IBAm_0.60) to cause an LCST. These modified polymers were then further substituted with hydrophobic alkyl chains (HPEI-IBAm_0.60-R_0.40), a mixture of alkyl chains and hydroxyethyl groups (HPEI-IBAm_0.60-EtOH_0.20-R_0.20), and a mixture of alkyl chains and low molecular weight PEG (HPEI-IBAm_0.60-PEG_0.20-R_0.20) to determine the effect of different functional groups on solubility behavior. At pH 7.4, all but three LCSTs were below body temperature (37 °C), while at pH 5, all but three LCSTs were above …