Chemistry Commons^™

Cellulose Acetate Replica Cleaning Study Of Genesis Non-Flight Sample 3cz00327, K.R. Kuhlman, Martina Schmeling, C.P. Gonzalez, J.H. Allton, D.S. Burnett

Chemistry: Faculty Publications and Other Works

Cellulose acetate replica cleaning of Genesis samples is validated using control sample 3CZ00327. Residues are removed using hot xylene and acetone.

Development, Characterization And Application Of Chiral Stationary Phases, Muhammad Abdul Momin Khan

Chemistry & Biochemistry Theses - Archive

Cyclofructans are cyclic oligosaccharides consisting of a crown ether core with pendent fructofuranose units. These unique macrocycles were reported recently to be powerful chiral selectors. Native cyclofructans show little enantioselectivity. However, when they are derivatized and bonded to silica, they make excellent chiral selectors for HPLC. In this study, several new derivatives of cyclofructan 6 were prepared by introducing aromatic selectors with electron-withdrawing chloro and nitro group(s) and electron-donating methyl group. Their enantioselectivities were evaluated in the normal phase mode in comparison to the commercially available cyclofructan columns (LARIHC CF6-P, LARIHC CF6-RN and LARIHC CF7-DMP). In several cases, the new …

Tailored Analytical Methods For Surveying Groundwater Quality In Areas Of Unconventional Drilling, Doug Dewayne Carlton Jr.

Chemistry & Biochemistry Dissertations - Archive

Many questions have been raised over the environmental impact of unconventional drilling techniques, especially on the groundwater of the extraction area. Analytical approaches and methods specific to hydraulic fracturing had to be developed due to the lack of available research at the time. The analytical approaches chosen for the extensive survey of groundwater quality included general groundwater measurements, bulk water characterization, and organic, inorganic, and ionic speciation. Some of the chosen targets included volatile and semivolatile ingredients in hydraulic fracturing fluid, metals associated with drilling fluids or formation waters, and total carbon and nitrogen measurements. These methods were developed and …

Optical Properties Of Secondary Organic Aerosols Using Ultraviolet/Visible Spectroscopy, Felisha Imholt

CUP Undergraduate Research

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. Our study aimed to discover how much radiation SOA particles absorb between ~200 and 800 nm. The SOA were created in one of two temperature controlled Teflon chambers within Dr. John Shilling’s lab at PNNL and were collected on 47 mm Teflon filters. We used an ultraviolet-visible (UV/Vis) spectrometer equipped with a liquid waveguide capillary flow …

The Use Of Molecular Dynamics To Predict The Stability Of Squaraine Rotaxanes, Ruth Nelson

CUP Undergraduate Research

Squaraine rotaxanes are fluorescent molecules comprised of two parts—a dumbbell-shaped squaraine dye threaded through a ring-shaped macrocycle—that are held together by hydrogen bonding, hydrophobic effects, and the size of the opening in the macrocycle1. Since the squaraine is an extremely electrophilic species3, nucleophilic attack by water is possible when it slips out of the macrocycle. This results in a loss of fluorescence. These near-IR dyes have many applications, including effective labeling of bacterial cells4. Previous studies have shown that the unprotected squaraine dye is unstable, and the adamantyl rotaxane degrades over time while the isophthalamidyl and pyridinyl rotaxanes remain stable2(Fig. …

Composition Of Secondary Organic Aerosols, Ryan Caylor, Felisha Imholt, Matthew Wise, John Shilling

CUP Undergraduate Research

The enhanced greenhouse effect is considered one our greatest global environmental problems. The amount of radiation absorbed by greenhouse gases is known to high certainty. However, absorbance from atmospheric aerosols particles is not. This study was conducted to determine the chemical composition of secondary organic aerosol particles (SOA) and to determine the compositional effect on their optical properties. The SOA were created in a temperature controlled chamber at Pacific Northwest National Laboratory (PNNL) in Richland, WA and collected on filters. The SOA were then analyzed for chemical composition using Fourier Transform Spectroscopy (FTIR). Analysis of the IR spectra revealed specific …

Optical Properties Of Secondary Organic Aerosols, Felisha Imholt, Ryan Caylor, Matthew Wise, John Shilling

CUP Undergraduate Research

It is well known that the increased warming effect due to greenhouse gases is a major environmental concern. While the amount of solar radiation absorbed by greenhouse gases is known to a high certainty, the amount absorbed by secondary organic aerosols (SOA) is not. The experimental procedure used to measure the amount of radiation absorbed by SOA was optimized using fulvic acid. The optimized method was then used to measure how much radiation SOA absorb between ~200 and 800 nm. Using this data, mass absorption coefficient (MAC) values at 405 nm and imaginary refractive indexes (k) were calculated. These values …

Composition And Optical Properties Of Secondary Organic Aerosol Particles, Felisha Imholt, Ryan Caylor, Matthew Wise, John Shilling

CUP Undergraduate Research

Research Questions:

• What is the chemical composition of SOA?
• Does SOA absorb UV/Vis radiation?
• If SOA does absorb UV/Vis radiation, how strong of an absorber is it?

Advancements In The Diastereoselective Synthesis Of Acyl Pyrrolidines Via The Tandem Aza-Cope—Mannich Cyclization Pathway, Danielle St. Germaine

Master's Theses and Doctoral Dissertations

We have developed a Lewis-acid catalyzed, diastereoselective aza-Cope rearrangement— Mannich cyclization to form acyl pyrrolidines from conformationally mobile substrates. In earlier studies from our lab, Brønsted acid-catalyzed reactions to form the same acyl pyrrolidines resulted in diastereoselectivities of 8:1 trans to cis at elevated temperatures (60 °C) over the course of 150 minutes. We have demonstrated an improvement in our method yielding exclusively the trans isomers at ambient temperature with substoichiometric amounts of BF₃•OEt₂ within 3 minutes. Catalyst loadings as low as 0.05 equivalents of BF₃•OEt₂ initiate this transformation. Our synthetic method employs the …

A Photoelectron Spectroscopy And Ab Initio Study Of The Structures And Chemical Bonding Of The B25 − Cluster, Zachary A Piazza, Ivan H. Popov, Wei-Li Li, Rhitankar Pal, Xiao Cheng Zeng, Alexander I. Boldyrev, Lai-Sheng Wang

Xiao Cheng Zeng Publications

Photoelectron spectroscopy and ab initio calculations are used to investigate the structures and chemical bonding of the B₂₅ − cluster. Global minimum searches reveal a dense potential energy landscape with 13 quasi-planar structures within 10 kcal/mol at the CCSD(T)/6-311+G(d) level of theory. Three quasi-planar isomers (I, II, and III) are lowest in energy and nearly degenerate at the CCSD(T) level of theory, with II and III being 0.8 and 0.9 kcal/mol higher, respectively, whereas at two density functional levels of theory isomer III is the lowest in energy (8.4 kcal/mol more stable than I at PBE0/6-311+G(2df) level). Comparison with …

Water Purification Through Ion Exchange, Brittany Webb

Natural Sciences Student Research Presentations

Water purification through ion exchange is the process of removing undesired contaminates from water through the exchange of ions between two electrolytes. Clinoptilolite is used as an exchange site.

Jupiter's Great Red Spot Is Composed Of Ammonia And Phosphine, Erika Rosenberger

Natural Sciences Student Research Presentations

In Jupiter's Great Red Spot, ammonia, phosphine, and para-Hydrogen were found. The Great Red Spot is the local maximum of ammonia, the most abundant compound of the atmosphere. The abundance of ammonia in the Spot is regulated by a complex interaction between photochemistry, condensation, precipitation, and atmospheric dynamics. Ammonia is found most abundant in the regions at around 400-500 mbar when phosphine is the most abundant at 600 mbar. The photo-dissociation reaction of phosphine that occurs in the Spot helps explain why the planet Jupiter and the Great Red Spot is red. The reaction sequence proposed by scientists Prinn and …

Functionalized Sulfone And Sulfonamide Based Poly(Arylene Ether)S, Marina Andrejevic

Browse all Theses and Dissertations

A series of fluorinated poly(arylene ether)s, PAE, bearing sulfonated pendent sulfonyl groups, was prepared. A range of Ion Exchange Capacity (IEC) values were achieved by varying the ratios of sulfonated and non sulfonated monomers. Incorporation of both of the monomers was confirmed by NMR spectroscopy and characterization of the thermal properties was done using thermogravimetric analysis (TGA) and differential scanning (DSC). Polymers with these IEC values were synthesized in order to explore their use as a potential alternatives to the widely studied proton exchange membrane, Nafion, with an IEC of 0.91 meq/g.

Using N-phenyl-3,5-difluorobenzene sulfonamide as the starting material a …

Rapid-Scan Epr Of Immobilized Nitroxides, Zhelin Yu, Richard W. Quine, George A. Rinard, Mark Tseitlin, Hanan Elajaili, Velavan Kathirvelu, Laura J. Clouston, Przemysław J. Boratyński, Andrzej Rajca, Richard A. Stein, Hassane Mchaourab, Sandra S. Eaton, Gareth R. Eaton

Andrzej Rajca Publications

X-band electron paramagnetic resonance spectra of immobilized nitroxides were obtained by rapid scan at 293 K. Scan widths were 155 G with 13.4 kHz scan frequency for ¹⁴N-perdeuterated tempone and for T4 lysozyme doubly spin labeled with an iodoacetamide spirocyclohexyl nitroxide and 100 G with 20.9 kHz scan frequency for ¹⁵N-perdeuterated tempone. These wide scans were made possible by modifications to our rapid-scan driver, scan coils made of Litz wire, and the placement of highly conducting aluminum plates on the poles of a Bruker 10" magnet to reduce resistive losses in the magnet pole faces. For the same …

Chelation And Stereodynamic Equilibria In Neutral Hypercoordinate Organosilicon Complexes Of 1-Hydroxy-2-Pyridinone, Bradley M. Kraft, William W. Brennessel

Chemistry Faculty/Staff Publications

A series of neutral organosilicon compounds, R3Si(OPO) [R = Me (1), Et (2), Ph (3)], cis-R2Si(OPO)2 [R = Me (4), Et (5), iPr (6), tBu (7), Ph (9)], (CH2)3Si(OPO)2 (8), and cis-R2Si(OPO)Cl [R = Me (10), Et (11)] (OPO = 1-oxo-2-pyridinone) have been prepared and fully characterized. X-ray crystallographic analyses show 1 to be tetracoordinate, 3, 7, and 10 to be pentacoordinate, and 4, 5, 6, 8, and 9 to be hexacoordinate. In the hexacoordinate structures, a mixture of diastereomers is observed in the form of C/N site disorder in each OPO ligand. Variable-temperature 13C and 29Si NMR studies indicate …

Photoactivatable Organic And Inorganic Nanoparticles In Cancer Therapeutics And Biosensing, Mona Mathew

Electronic Theses and Dissertations

In photodynamic therapy a photosensitizer drug is administered and is irradiated with light. Upon absorption of light the photosensitizer goes into its triplet state and transfers energy or an electron to oxygen to form reactive oxygen species (ROS). These ROS react with biomolecules in cells leading to cell damage and cell death. PDT has interested many researchers because of its non-invasiveness as compared to surgery, it leaves little to no scars, it is time and cost effective, it has potential for targeted treatment, and can be repeated as needed. Different photosensitizers such as porphyrines, chlorophylls, and dyes have been used …

1, 2, And 3 Dimension Carbon/Silicon Carbon Nitride Ceramic Composites, Flores Jean Calderon

Electronic Theses and Dissertations

Polymer-derived ceramics (PDCs) are exceptional ultra-high temperature and stable multifunctional class of materials that can be synthesized from a polymer precursor through thermal decomposition. The presented research focuses on 1-D nanofibers, 2-D films and 3-D bulk, carbon-rich silicon carbon nitride (SiCN) ceramics. 1-D nanofibers were prepared via electrospinning for light weight, flame retardant and conductive applications. The commercially available CerasetTM VL20, a liquid cyclosilazane pre-ceramic precursor, was mixed with polyacrylonitrile (PAN) in order to make the cyclosilazane electrospinnable. Carbon-rich PDC nanofibers were fabricated by electrospinning various ratios of PAN/cyclosilazane solutions followed by pyrolysis. Surface morphology of the electro spun nanofibers …

Synthetic Strategies To Probe Enzymatic Activity: Investigation Of A Novel Oxygen-Dependent Non-Heme Diiron Monooxygenase (Miae), Andra Lynn Corder

Chemistry & Biochemistry Dissertations - Archive

Within the anticodon stem loop (ACSL) of tRNA, nucleoside modifications are frequently observed at position 34 (the wobble position) or position 37 (3' adjacent to the anticodon). For instance, nearly all eukaryotic and bacterial tRNAs that read codons starting with uridine are modified by the enzymes MiaA and MiaB. While absent in eukaryotes, some facultative bacteria utilize a non-heme diiron enzyme (MiaE) to catalyze the O2₂-dependent hydroxylation of 2-thiomethyl-N₆-(3-methyl-2-butenylamino) adenosine (ms²i⁶A₃₇) to produce 2-methylthio-N⁶-(4-hydroxyisopentenyl)-adenosine (ms²io⁶A₃₇). In these bacteria, it has been postulated that the extent of the A37-hydroxylation is involved in regulating aromatic amino acid uptake, iron transport, and aerobiosis. …

New Methods For Trace Analysis Of Iodine And Perchlorate In Biological Fluids, Charles Phillip Shelor

Chemistry & Biochemistry Dissertations - Archive

Iodine is an essential element necessary for the production of the thyroid hormones T3 and T4. These hormones are necessary for metabolism and are especially important for brain development in infants and young children. Iodine is transported into the thyroid by the sodium iodide symporter. Perchlorate is known to inhibit iodine uptake into the thyroid by binding to the sodium iodide symporter, thus acting as a potential neurotoxicant for developing children.The research in this dissertation consists of two goals. The primary is the development of novel methods for measuring iodine and perchlorate and the second is performing analyses to determine …

Investigation Of Pyrrolizidine Alkaloids In Foods Using Liquid Chromatography Mass Spectrometry, Caroline Griffin

PhDs

Pyrrolizidine Alkaloids (PAs) are known plant toxins which can cause hepatic veno-occlusive disease (HVOD) in both humans and livestock when ingested. Although PAs are primarily known for their hepatotoxicity they also induce genotoxicity, carcinogenicity and pneumotoxicity. PAs are consumed through plants as food, for medicinal purposes, or as contaminants of agricultural crops. Aside from ingesting the plants directly PA exposure may occur through the consumption of honey produced by bees that visit PA-containing plants or by drinking milk produced by animals that have consumed PA-containing plants. Possible PA contamination in our food chain is a potential health risk.

To assess …

The Development Of Liquid Chromatography Mass Spectrometry Methods For The Analysis Of Cyanobacterial Toxins In Environmental Freshwaters, Brian Anthony Dineen

Theses

Cyanobacteria, also known as blue-green algae, are a common component of many freshwater and marine ecosystems and have a potential to produce several different classes of biotoxins. The most common class of cyanobacterial toxins are the microcystins (MCs) and cylindrospermopsins (CYLs). MCs are cyclic heptapeptides that display potent hepatotoxicity and are tumour promoters. CYLs are alkaloids that are cytotoxic and can cause illness and display hepatotoxic effects in animals and humans. Worldwide, these toxins have caused fatal poisonings to animals, birds and fish. Several incidents of human intoxications have been reported and the presence of these toxins in environmental waters …

Investigation Of Pyrrolizidine Alkaloids In Foods Using Liquid Chromatography Mass Spectrometry, Caroline Griffin

Theses

Pyrrolizidine Alkaloids (PAs) are known plant toxins which can cause hepatic veno-occlusive disease (HVOD) in both humans and livestock when ingested. Although PAs are primarily known for their hepatotoxicity they also induce genotoxicity, carcinogenicity and pneumotoxicity. PAs are consumed through plants as food, for medicinal purposes, or as contaminants of agricultural crops. Aside from ingesting the plants directly PA exposure may occur through the consumption of honey produced by bees that visit PA-containing plants or by drinking milk produced by animals that have consumed PA-containing plants. Possible PA contamination in our food chain is a potential health risk.

To assess …

Specific Intracellular Uptake Of Herceptin-Conjugated Cdse/Zns Quantum Dots Into Breast Cancer Cells, Seung-Jin Han, Pierson Rathinaraj, Soo-Young Park, Young-Kyoo Kim, Joon Hyung Lee, Inn-Kyu Kang, Jong-Sik Moon, Jeffrey G. Winiarz

Chemistry Faculty Research & Creative Works

Herceptin, a typical monoclonal antibody, was immobilized on the surface of CdSe/ZnS core-shell quantum dots (QDs) to enhance their specific interactions with breast cancer cells (SK-BR3). the mean size of the core-shell quantum dots (28 nm), as determined by dynamic light scattering, increased to 86 nm after herceptin immobilization. the in vitro cell culture experiment showed that the keratin forming cancer cells (KB) proliferated well in the presence of herceptin-conjugated QDs (QD-Her, 5 nmol/mL), whereas most of the breast cancer cells (SK-BR3) had died. to clarify the mechanism of cell death, the interaction of SK-BR3 cells with QD-Her was examined …

Synthesis, Optical Properties And Photovoltaic Applications Of Hybrid Rod-Coil Diblock Copolymers With Coordinatively Attached Cdse Nanocrystals, Shaohua Li, Yong Li, Clarissa A. Wisner, Lu Jin, Nicholas Leventis, Zhonghua Peng

Chemistry Faculty Research & Creative Works

The performance of hybrid solar cells based on conjugated polymers and nanostructured inorganic semiconductors is often limited by the poor interfacial interaction and the lack of controlled phase separation. Improvements are being made by building intimate contact between the two components through coordinative linkages. in this contribution, three rod-coil diblock copolymers (DCPs) of the modified poly(3-hexylthiophene)-polystyrene (P3HT-PS) type with different phosphorus-containing functional groups for binding to inorganic nanoparticles are reported. Their corresponding P3HT-PS-CdSe hybrid DCPs (HDCPs) were prepared by ligand-exchange with chemically prepared CdSe nanocrystals. the three DCPs have different size disparity between the rod and coil blocks, where the …

Antioxidant Potential Of Sutherlandia Frutescens And Its Protective Effects Against Oxidative Stress In Various Cell Cultures, Shakila Tobwala, Weili Fan, Connor J. Hines, William Robert Folk, Nuran Ercal

Chemistry Faculty Research & Creative Works

Sutherlandia frutescens (L.) R.Br. (SF) is a South African plant that is widely used to treat stress, infections, cancer, and chronic diseases, many of which involve oxidative stress. The aim of the study was to quantitatively assess the antioxidant potential of SF extracts in cell-free system as well as in cell lines. Dried SF vegetative parts were extracted using six different solvents, and the extracts were assessed for total phenolic and flavonoid contents, total reducing power, iron chelating capacity, and free radical scavenging power, including, scavenging of hydroxyl radicals, superoxide anions, nitric oxide, and hydrogen peroxide. We further investigated the …

Scanning Probe Investigations Of Magnetic Nanoparticles, Protein Binding And The Synthesis Of Rare Earth Oxide Nanoparticles Using Nanoscale Lithography, Lauren Elizabeth Englade-Franklin

LSU Doctoral Dissertations

Approaches to prepare spatially selective surfaces were developed in this dissertation for constructing assemblies of biomolecules and inorganic materials. Nanoscale surface patterns of organic thin films were prepared using particle lithography combined with organosilane chemistry. Biological and inorganic nanomaterials can be patterned with tailorable periodicities, which can be controlled by selecting the diameter of mesospheres used as surface masks. The surface platforms of well-defined nanopatterns are ideal for high resolution investigations using scanning probe microscopy (SPM). Local measurements of surface properties combined with visualization of the steps of chemical reactions at the molecular level were accomplished. Fundamental studies of the …

Syntheses And Characterization Of Isoporphyrins And Bodipys For Pdt And Imaging, Haijun Wang

LSU Doctoral Dissertations

This Dissertation is divided into five chapters reporting various aspects of the background to my field of study and the results obtained during my research program. Chapter 1 gives a very brief introduction to photodynamic therapy including the mechanism of the treatment, the localization of photosensitizer in tumor cells, the pathways leading to tumor death and characteristics of various photosensitizers such as porphyrin-based photosensitizers and non-porphyrin based photosensitizers. Chapter 2 reports a total synthesis of zinc(II) isoporphyrins by cyclization of b-bilene salt using á-keto esters for the macrocyclization carbon. Functionalization of the resulting zinc(II) isoporphyrins was attempted using different strategies …

Chemistry Students’ Attitudes About Peer-Led Team Learning Workshops: Comparison To The Six Critical Components, A.E. Dreyfuss, Janet Liou-Mark, Leo Gafney

Publications and Research

While tracking students’ performance and perseverance is important to determine the effect of the incorporation of workshops in courses, little has been published on students’ attitudes toward workshops: How do students feel about PLTL workshops? One method of examining this question is through a questionnaire developed by Gafney. This paper will present the results of a three-semester study using this questionnaire on how students view workshop in their introductory chemistry courses.

Basic Features Of A Cell Electroporation Model: Illustrative Behavior For Two Very Different Pulses, Reuben S. Son, Kyle C. Smith, Thiruvallur R. Gowrishankar, P. Thomas Vernier, James C. Weaver

Bioelectrics Publications

Science increasingly involves complex modeling. Here we describe a model for cell electroporation in which membrane properties are dynamically modified by poration. Spatial scales range from cell membrane thickness (5 nm) to a typical mammalian cell radius (10 μm), and can be used with idealized and experimental pulse waveforms. The model consists of traditional passive components and additional active components representing nonequilibrium processes. Model responses include measurable quantities: transmembrane voltage, membrane electrical conductance, and solute transport rates and amounts for the representative "long" and "short" pulses. The long pulse-1.5 kV/cm, 100 μs-evolves two pore subpopulations with a valley at ~5 …

A Review Of The Hyporheic Zone, Stream Restoration, And Means To Enhance Denitrification, Leanne Merill, David J. Tonjes

Technology & Society Faculty Publications

The hyporheic zone is the subsurface area below and adjacent to a stream where groundwater mixes with stream water, through vertical, lateral, and longitudinal flows. The hyporheic zone connects the stream to uplands and other terrestrial environments. It is a zone of distinct faunal communities, high biological diversity and ecological complexity, and is the site of chemical processing and transformations of ground- and stream waters. The hyporheic zone is important to the overall ecosystem ecology of the stream, and it can influence stream water chemistry. Flows, reactions, and biota in the hyporheic zone are heterogeneous and patchy, making it difficult …