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Electrochemically Induced Free Radical Polymerization Of Methacrylic Acid And Fabrication Of Amperometric Glucose Biosensor, Sheng Wang, Ying Lei, Kang Shi

Journal of Electrochemistry

Electrochemically induced free radical polymerization of methacrylic acid was preliminarily investigated. Based on the electrochemical reduction of persulfate anion in phosphate buffer (pH 7.0) solution,the free radical polymerization of methacrylic acid was initiated to generate an ultrathin and biocompatible hydrogel layer on the gold electrode. At the meantime,glucose oxidase could be immobilized within the hydrogel film in the polymerization process. The resulting biosensor displayed an attractive performance.

Characterization Of Dissolved Organic Matter By Separation And Fluorescence Spectroscopy, Yurong Deng

Chemistry and Chemical Biology ETDs

The goal of this work is to evaluate new methods of extracting and fractionating dissolved organic matter (DOM) using liquid-liquid and solid-phase extraction (SPE), monitored by optical spectroscopy. DOM in aquatic systems from different sources was characterized by three-dimension excitation-emission matrix fluorescence spectroscopy (3DEEMS) and UV absorbance spectroscopy. UV and visible humic-like fluorescence were observed in all water samples -- humic acids (HA), fulvic acids (FA), river water, wastewater, and their fractionations. Their fluorescence centers varied with environment in the range of λex/ λem = 220-250 nm/390-460 nm for UV humic-like fluorescence (peak A) and λex/ λem = 300-340 nm/390-460 …

Total Synthesis Of (-)-Acutumine, Fang Li

Theses and Dissertations

Acutumine is a tetracyclic alkaloid isolated from the Asian vine Menispermum dauricum with selective T-cell cytotoxicity and antiamnestic properties. We have developed a total synthetic route to this congested alkaloid, during which we also found a novel, stereoselective radical-crossover reaction that combines an intramolecular radical conjugate addition with a subsequent enolate hydroxylation. Key features of this synthesis also include a reagent-controlled diastereoselective ketone allylation, an anionic oxy-Cope rearrangement to form a congested quaternary sterocenter, a pyridine-mediated selective ozonolysis, and a Lewis acid promoted Michael-type cyclization.

Computational Investigation Of Spin Traps Using Hybrid Solvation Models., Sai Sriharsha Manoj Konda

Electronic Theses and Dissertations

The cyclic nitrone 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and the lesser known linear phenyl-N-tert-butylnitrone (PBN) and its phosphorylated analogues have been used as spin traps for the investigation of free radicals in biological systems. Theoretical work on these molecules suggests that there are important differences in their properties between biological systems and isolated molecules in the gas phase, most likely resulting from intra and intermolecular hydrogen bonding. Most dielectric solvation models such as the polarized continuum model and COSMO are incapable of direct determination of solvent-spin trap chemical interactions. To examine this, hybrid models incorporating COSMO for long range effects and discrete solvent …

Studies Of The Preparations And Use Of Sol-Gel For Enzyme Immobilization And Analytical Applications., Suzana Hamdan

Electronic Theses and Dissertations

Much attention has been paid to immobilization of enzymes to improve enzyme stability and permit its reuse. Glucose oxidase entrapment in different kinds of silica sol-gel matrices was investigated. The enzyme showed stable activity for 11 uses in the sol-gel with tetramethyl orthosilicate (TMOS) as precursor, and at least 7 uses in the sol-gel induced electrochemically with tetraethyl orthosilicate (TEOS) as precursor. The sol-gel made with TEOS as precursor and HCl as catalyst showed stability in enzyme activity for 11 uses but the activity decreases on the same sol-gel when modified with silica nanoparticles. Factors such as optimal incubation time …

Novel Strategy For The Synthesis Of Allenes., Mark-Henry Mbahmi Kamga

Electronic Theses and Dissertations

Allenes are very important chemical reagents in organic synthesis. Due to their high reactivity, they have been extensively used to carry out a variety of unique and effective chemical transformations including but not limited to ionic and free radical additions and transition metal catalyzed cyclizations. As the chemistry of this group of compounds is explored further and their applications expanded there is a need to develop alternative and cost effective methods for their synthesis. Our approach involves the synthesis of allenes from oxa-bicyclo-alkan-2-ones by methyllithium induced Eschenmoser fragmentation of the bicyclotosylhydrazone derivatives.

Studies Of Capsaicinoids Contents Of Locally Grown And Commercial Chilies Using Reversed-Phase High Performance Liquid Chromatography., John Kailemia Muchena

Electronic Theses and Dissertations

Capsaicinoids are a class of compounds responsible for the "heat" of hot peppers. Capsaicin and dihydrocapsaicin have the highest burning effect. The aim of this work is to separate and quantify the two major capsaicinoids in fruits harvested at different stages of development and at different seasons. Simple and rapid HPLC method involves 73:27% methanol water mobile phase with C₁₈ stationary phase and UV-Vis detector set at 210 nm. The method showed good reproducibility with 1.74% - 4.72% relative standard deviations, a linear response within 0.65–45.5 and 0.25-17.5 μg/mL for capsaicin and dihydrocapsaicin, respectively. The method achieved average recovery …

Studies Of Titanium Dioxide Nanoparticles And Surfactants Effects, Singly And In Combinations, On Luminescence Intensity Of Some Aromatic Compounds., Charles Anim Odame-Ankrah

Electronic Theses and Dissertations

Luminescence techniques are sensitive, selective, and widely used in analysis. Luminescence intensity is attenuated by quenchers. This research has focused on the use of surfactants such as CTAB, SDS, and TX-100 singly or together with TiO₂ nanoparticles to evaluate their individual and combined effects on some fluorescent aromatic compounds such as pyrene, fluoranthene, anthracene, phenanthrene, and carbazole. Rutile phase TiO₂ was synthesized using the low temperature sol-gel method. Carbazole and phenanthrene were severely quenched by all surfactants singly or in combination with TiO₂. Anthracene and fluoranthene showed some enhancement in their luminescence intensity. The most dramatic …

Single Molecule Force Spectroscopy On G-Quadruplex Dna, Susanna Lynch, Heather Baker, Sarah G. Byker, Dejian Zhou

University Faculty Publications and Creative Works

A study was conducted to demonstrate the first atomic force microscopy (AFM) based investigation of single-molecule (SM) force spectroscopy (FS). A bimolecular G-quadruplex formed between the AFM probe and a gold surface was used as the model system to conduct the investigations. A gold-coated Si 3N4 probe and a flat gold surface were functionalized with a self-assembled monolayer (SAM) of the 3G or 4G DNA. A loading rate dependence investigation was conducted to estimate kinetic and thermodynamic parameters of the 3G and 4G quadruplexes. Rupture forces were measured at loading rates ranging from 1027-43 500 pNs-1. It was observed that …

Single Molecule Force Spectroscopy On G-Quadruplex Dna, Susanna Lynch, Heather Baker, Sarah G. Byker, Dejian Zhou

University Faculty Publications and Creative Works

A study was conducted to demonstrate the first atomic force microscopy (AFM) based investigation of single-molecule (SM) force spectroscopy (FS). A bimolecular G-quadruplex formed between the AFM probe and a gold surface was used as the model system to conduct the investigations. A gold-coated Si 3N4 probe and a flat gold surface were functionalized with a self-assembled monolayer (SAM) of the 3G or 4G DNA. A loading rate dependence investigation was conducted to estimate kinetic and thermodynamic parameters of the 3G and 4G quadruplexes. Rupture forces were measured at loading rates ranging from 1027-43 500 pNs-1. It was observed that …

Structural Basis For Α-Conotoxin Potency And Selectivity, Matthew Turner, Seth Eidemiller, Bryan Martin, Andrew Narver, Joshua Marshall, Kenneth A. Cornell, Owen M. Mcdougal

Chemistry and Biochemistry Faculty Publications and Presentations

Parkinson's disease is a debilitating movement disorder characterized by altered levels of α₆β₂* nicotinic acetylcholine receptors (nAChRs) localized on presynaptic striatal catecholaminergic neurons. α-Conotoxin MII (α-CTx MII) is a highly useful ligand to probe α₆ß₂ nAChRs structure and function, but it does not discriminate among closely related α₆* nAChR subtypes. Modification of the α-CTx MII primary sequence led to the identification of α-CTx MII[E11A], an analog with 500-5300 fold discrimination between α₆* subtypes found in both human and non-human primates. α-CTx MII[E11A] binds most strongly (femtomolar dissociation constant) to …

Distance Dependence Of Electron Transfer Kinetics For Azurin Protein Adsorbed To Monolayer Protected Nanoparticle Film Assemblies, Morgan Lynn Vargo, Chris P. Gulka, John K. Gerig, Christopher M. Manieri, Jonathan D. Dattelbaum, Carolyn B. Marks, Nathaniel T. Lawrence, Matthew L. Trawick, Michael C. Leopold

Chemistry Faculty Publications

The distance dependence and kinetics of the heterogeneous electron transfer (ET) reaction for the redox protein azurin adsorbed to an electrode modified with a gold nanoparticle film are investigated using cyclic voltammetry. The nanoparticle films are comprised of nonaqueous nanoparticles, known as monolayer-protected clusters (MPCs), which are covalently networked with dithiol linkers. The MPC film assembly serves as an alternative adsorption platform to the traditional alkanethiolate self-assembled monolayer (SAM) modified electrodes that are commonly employed to study the ET kinetics of immobilized redox proteins, a strategy known as protein monolayer electrochemistry. Voltammetric analysis of the ET kinetics for azurin adsorbed …

Development Of Biocompatible Polymer Monoliths For The Analysis Of Proteins And Peptides, Yun Li

Theses and Dissertations

Biocompatibility is an important issue for the development of chromatographic stationary phases for the analysis of biomolecules (including proteins and peptides). A biocompatible stationary phase material is a material that resists nonspecific adsorption of biomolecules and does not interact with them in a way that would alter or destroy their structures or biochemical functions. The monolithic column format is a good alternative to typical spherical particle packed columns for capillary liquid chromatography of biomacromolecules. Several novel anion-exchange polymer monoliths for the analysis of proteins were synthesized for improved biocompatibility. Two novel polymeric monoliths were prepared in a single step by …

Real-Time Virus Analysis Via Image Charge Detection Surface Induced Dissociation Tandem Mass Spectrometry, Seth T. Call

Theses and Dissertations

This thesis reports on the development of a novel mass spectrometer combining image charge detection with surface induced dissociation for real-time analysis of intact viruses. Protonated viruses produced using electrospray are accelerated and subsequently impact on a solid surface. Capsid peptides released during the impact are analyzed using time-of-flight mass spectrometry. Image charge detection is used to measure the mass and charge states of structurally intact, electrosprayed viruses prior to impact. Since virus capsids are composed of loosely-bound proteins, collision of viruses with surfaces at moderate impact energies could release intact proteins. The masses and numbers of different protein types …

Mesoporosity And Functional Group Dependent Endocytosis And Cytotoxicity Of Silica Nanomaterials, Zhimin Tao, Jerry Goodisman, Tewodros Asefa, Bonnie B. Toms

Chemistry - All Scholarship

We report different mesoporosity-dependent and functional group-dependent cytotoxicity and endocytosis of various silica nanomaterials on suspended and adherent cells. This dependency further varied with incubation time and particle dosage, and appeared to be associated with the particles’ endocytotic efficiency and their chemical and physical properties. We studied two common mesoporous nanomaterials (MSNs), MCM-41 and SBA-15, and one type of solid-cored silica microsphere, paralleled by their quaternary amine functionalized counterparts. Compared to SBA-15, MCM-41 has a larger surface area but smaller pore size, whereas SMS exhibits low surface area and poor porosity. In Jurkat cells, SBA-15 and MCM- 41 exhibited different …

Mesoporosity And Functional Group Dependent Endocytosis And Cytotoxicity Of Silica Nanomaterials, Zhimin Tao, Bonnie B. Toms, Jerry Goodisman, Tewodros Asefa

Chemistry - All Scholarship

We report different mesoporosity-dependent and functional group-dependent cytotoxicity and endocytosis of various silica nanomaterials on suspended and adherent cells. This dependency further varied with incubation time and particle dosage, and appeared to be associated with the particles' endocytotic efficiency and their chemical and physical properties. We studied two common mesoporous nanomaterials (MSNs), MCM-41 and SBA-15, and one type of solid-cored silica microsphere, paralleled by their quaternary amine functionalized counterparts. Compared to SBA-15, MCM-41 has a larger surface area but smaller pore size, whereas SMS exhibits low surface area and poor porosity. In Jurkat cells, SBA-15 and MCM-41 exhibited different cytotoxicity …

Design And Characterization Of A Human Exposure Chamber And Inversion Episodes In Salt Lake City, Utah In January/February Of 2009, Roman Yuri Kuprov

Theses and Dissertations

Research on health effects of particulate matter (PM) has been a very active area in the last two decades. One plausible mechanism by which exposure to PM affects human health includes modification of autonomic endothelium function. Decreased endothelium activity causes heightened risks of cardiovascular disease. A human exposure chamber designed to conduct experiments to quantify diminished function of endothelium from short term exposure to PM is described. The chamber consists of two stages for containment and pre-treatment of PM and exposure of human subjects. Concentrations of CO, CO2, NO, NO2, O3, and PM2.5, are monitored and controlled in the exposure …

Undergraduate Research Opportunities Program, University Of Nevada Las Vegas, College Of Sciences

Undergraduate Research Opportunities Program (UROP)

No abstract provided.

The Study Of Variations In The Properties Of Biodiesel On Addition Of Antioxidants, Hiranmayee Kandala

Masters Theses & Specialist Projects

This research studies variations in biodiesel upon addition of different concentrations of antioxidant and petrodiesel additives. Oxidation onset temperature, oxidation induction time, oxidative stability, thermal stability, crystallization onset temperature and moisture retention properties of the biodiesel, with and without antioxidants have been studied. Antioxidants like BHT, BHA, PrG, Vit E and Vit C were added to the biodiesel during the study. These samples were analyzed using the PDSC, TGA, DSC and TGA-SA instrumentation.

The results of this research show an improvement in the OOT, OIT and Oxidative stability of biodiesel with the addition of antioxidants and by blending the biodiesel …

Synthesis And Characterization Of Bis-Phosphine Complexes With Transition Metals, Alicia L. Mcdaniel

Masters Theses & Specialist Projects

Extractants and extraction methodologies play a vital role in many industrial processes, from the concentration of precious metals from ores to the separation of longlived nuclei from radioactive waste as well as the removal of heavy metals from soils and water for remediation. The vast majority of extractants rely on the use of nitrogen, oxygen, sulfur or selenium as Lewis base donor atoms to form coordination complexes with the metal ions of interest. These extractants often make use of the chelate effect and/or the macrocyclic effect in order to form stable complexes. Some of the best known types of chelate …

Isu Chem-Letter, Fall 2009, Illinois State University, Department Of Chemistry

Chem Letter

Newsletter of the Illinois State University Department of Chemistry

Continued Development Of An Empirical Function For Predicting And Rationalizing Protein–Protein Binding Affinities, Joseph Audie

Chemistry & Physics Faculty Publications

Here we summarize recent work on the continued development of our fast and simple empirical equation for predicting and structurally rationalizing protein–protein and protein–peptide binding affinities. Our empirical expression consists of six regression-weighted physical descriptors and derives from two key simplifying assumptions: (1) the assumption of rigid-body association and (2) the assumption that all contributions not explicitly considered in the equation make a net contribution to binding of ≈0 kcal. Within the strict framework of rigid-body association, we tested relative binding affinity predictions using our empirical equation against the corresponding experimental binding free energy data for 197 interface alanine mutants. …

Phenomenological Investigation Of The Effectiveness Of A Cooperative Problem-Based Laboratory And A Metacognitive Problem-Solving Exercise, Todd Gatlin

All Theses

Problem-solving has been described by many as the most important goal of chemistry teaching and learning. Solving real problems requires not only cognitive abilities but also a regulation of those abilities-metacognition. In fact, metacognition is recognized as having considerable impact on problem-solving success and learning. Recent research focused on the development of interventions designed to enhance the use of metacognition. The main objective of this study was to determine 'how' and 'why' two interventions were effective in increasing students' metacognitive use, and problem-solving abilities. Therefore, this study represents the qualitative portion of a sequential explanatory mixed-methods study; Qualitative evidence was …

Classification And Energetics Of The Base-Phosphate Interactions In Rna, Craig L. Zirbel, Judit E. Šponer, Jiri Šponer, Jesse Stombaugh, Neocles B. Leontis

Chemistry Faculty Publications

Structured RNA molecules form complex 3D architectures stabilized by multiple interactions involving the nucleotide base, sugar and phosphate moieties. A significant percentage of the bases in structured RNA molecules in the Protein Data Bank (PDB) hydrogen-bond with phosphates of other nucleotides. By extracting and superimposing base-phosphate (BPh) interactions from a reduced-redundancy subset of 3D structures from the PDB, we identified recurrent phosphate-binding sites on the RNA bases. Quantum chemical calculations were carried out on model systems representing each BPh interaction. The calculations show that the centers of each cluster obtained from the structure superpositions correspond to energy minima on the …

Effects Of Adding An Enhanced Material Instructional Model To A Collaborative Grouping Instructional Strategy In A College Preparatory Chemistry Course, Chinyere Fidelia Shaw-Nnajiofor

Theses and Dissertations - UTB/UTPA

This research study investigated comparable academic achievement outcomes between an experimental group (EG) and a control group (CG) in a college preparatory chemistry course using a mixture of instructional pedagogies. The subjects comprised native and non-native English speakers, often identified as Limited English Proficiency (LEP) students. The study found no statistically significant difference between the pre-test scores of EG and CG students and a significant difference between the post-test scores of students in the experimental group compared to those of the control group. No significant difference was observed when comparing the test scores of the post-tests of the LEP-EG students …

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson

All Theses

This report details the synthesis of functionalized platinum-based metallopolymers featuring m-terphenyl-scaffolded and light-harvesting phosphine ligands. Substituents placed on both the phosphine and pendant alkynyl units can enhance the optical activity of the metallopolymers depending on their inherent properties. The presence of the platinum metal atom can be exploited to increase conductivity of the molecule and promises to be a unique and valuable modification for polymers to be used in light emitting diodes and photovoltaics. Light-harvesting phosphines prepared in the course of the metallopolymer development have also been used to prepare luminescent polyelectrolytes that prove valuable for well-defined composite film formation …

Understanding The Antioxidant Mechanism Of Inorganic Selenium, Oxo- Sulfur, And Polyphenol Compounds, And The Biological Implications Of Functionalized Nanoparticles, Ria Ramoutar

All Dissertations

Inorganic selenium, oxo-sulfur, and polyphenol compounds are found in foods and dietary supplements, and are recognized for their nutritional benefits and their potential to treat or prevent diseases caused by oxidative stress. In our experiments to determine the effects of inorganic selenium compounds on iron-mediated DNA damage, Na₂SeO₃3 and SeO₂ exhibit antioxidant and pro-oxidant activities depending on concentrations of both the compound and hydrogen peroxide. Additional experiments demonstrate that iron coordination is a novel mechanism responsible for the observed activities. In similar experiments, oxo-sulfur compounds prevent Cu+/ H₂O₂-mediated DNA damage significantly …

Development Of Improved Torsional Potentials In Classical Force Field Models Of Poly (Lactic Acid), James Mcaliley

All Dissertations

In this work, existing force field descriptions of poly (lactic acid), or PLA, were improved by modifying the torsional potential energy terms to more accurately model the bond rotational behavior of PLA. Extensive calculations were carried out using density functional theory (DFT), for small PLA molecules in vacuo, and also using DFT with a continuum model to approximate the electronic structure of PLA in its condensed phase. From these results, improved force field parameters were developed using a combination of the OPLS and CHARMM force fields. The new force field, PLAFF2, is an update to the previously developed PLAFF model …

Does Organic Modification Of Layered Double Hydroxides Improve The Fire Performance Of Pmma?, Calistor Nyambo, Dan Chen, Shengpei Shu, Charles A. Wilkie

Chemistry Faculty Research and Publications

The effect of modified layered double hydroxides (LDHs) on fire properties of poly(methyl methacrylate) is investigated. Organically-modified LDHs were prepared via rehydration of calcined hydrotalcite in a palmitate solution. Composites consisting of the organo-LDHs, unmodified hydrotalcite and calcined oxides were prepared with poly(methyl methacrylate) using melt blending. Thermal and fire properties of the (nano)composites were studied. The thermogravimetric analyses of the composites show an increase in thermal stability. Fire performance, evaluated using cone calorimetry, show that organically-modified LDHs composites give the best reductions in peak heat release rate, PHRR, i.e., 51% at 10% weight loading. Dispersion of the LDHs was …

Recent Applications Of Acyclic (Diene)Iron Complexes And (Dienyl)Iron Cations In Organic Synthesis, William A. Donaldson, Subhabrata Chaudhury

Chemistry Faculty Research and Publications

Complexation of (tricarbonyl)iron to an acyclic diene serves to protect the ligand against oxidation, reduction, and cycloaddition reactions, whereas the steric bulk of this adjunct serves to direct the approaches of reagents to unsaturated groups attached to the diene onto the face opposite to iron. Furthermore, the Fe(CO)₃ moiety can serve to stabilize carbocation centers adjacent to the diene (i.e. pentadienyl-iron cations). Recent applications of these reactivities to the synthesis of polyene-, cyclopropane-, cycloheptadiene-, and cyclohexenone-containing natural products or analogues are presented.