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Laughlin '14 Selected As Nsf Scholar, Mallika Kavadi

News and Events (Discontinued Series)

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Flow-Tube Oxidation Experiments On The Carbon Preform Of Pica, Francesco Panerai, Alexandre Martin, Nagi N. Mansour, Steven A. Sepka, Jean Lachaud

Mechanical Engineering Faculty Publications

Oxidation experiments on the carbon preform of a phenolic-impregnated carbon ablator were performed in the NASA Ames ow-tube reactor facility, at temperatures between 700 and 1300 K, under dry air gas at pressures between 103 and 104 Pa. Mass loss, volumetric recession and density changes were measured at different test conditions. An analysis of the diffusion/reaction competition within the porous material, based on the Thiele number, allowed us to identify low temperature and low pressure conditions to be dominated by in-depth volume oxidation. Experiments above 1000 K were found at transition conditions, where diffusion and reaction occur at similar scales. …

Latent Cysteine Residues From Polymers Prepared Via Free And Controlled Radical Polymerizations, Douglas Vincent Amato

Master's Theses

One less commonly used “click” reaction is thiazolidine chemistry. Thiazolidine chemistry is a commonly used reaction used in biological systems because the reaction requires the presence of both cysteine (a common amino acid) and an aldehyde or ketone. If cysteine residues could be incorporated into a polymer then a variety of applications could be developed. Polymers containing free thiols (aka thiomers) have developed in the last decade to become great mucoadhesives. If there was a facile route to control the amount of free thiols along the polymer then more fine-tuned and potentially stronger adhesives could be made. For these reasons …

Unraveling The Activation Mechanism Of The Potato Tuber Adp-Glucose Pyrophosphorylase, Carlos M. Figueroa, Misty L. Kuhn, Christine A. Falaschetti, Ligin Solamen, Kenneth W. Olsen, Miguel Ballicora, Alberto A. Iglesias

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase regulates the synthesis of glycogen in bacteria and of starch in plants. The enzyme from plants is mainly activated by 3-phosphoglycerate and is a heterotetramer comprising two small and two large subunits. Here, we found that two highly conserved residues are critical for triggering the activation of the potato tuber ADP-glucose pyrophosphorylase, as shown by site-directed mutagenesis. Mutations in the small subunit, which bears the catalytic function in this potato tuber form, had a more dramatic effect on disrupting the allosteric activation than those introduced in the large subunit, which is mainly modulatory. Our results strongly agree with …

Stability And Precipitation Of Diverse Nanoparticles, Chintal Desai

Dissertations

Nanotechnology is a rapidly growing industry that is exploiting the novel characteristics of materials manufactured at the nanoscale. Carbon based nanomaterials such as Carbon Nanotubes (CNTs) and Detonation Nanodiamond (DND) possess unique properties and find a wide range of industrial applications. With the advent of mass production of such materials, there is a possibility of contamination of water resources. Depending on the surface properties and structures, they might aggregate and settle down, or be dispersed and transported by the water. Therefore, there is a need to develop an understanding of the fate of such materials in aqueous media. The understanding …

Application Of Hydrogen Peroxide As Brown Tide Bloom Control Agent, Varunpreet Randhawa

Dissertations

Harmful algal blooms (HABs) are growing problem across the globe. One such HAB that’s recurring in the coastal waters of New York and New Jersey since mid-1980s, and has been reported in other countries recently, is brown tide bloom. The causal organism is a minute pel agophyte (cell diameter ~- 2µ m) Aureococcus anophagefferens. The brown tide bloom has been responsible for the severe ecological damage and economic loss (e.g. shellfishery) in the affected areas. This research focuses on finding a method to control brown tide blooms and explores the potential of natural chemical biocide hydrogen peroxide (H_{2 …}

Escherichia Coli 2-Oxoglutarate Dehydrogenase Multienzyme Complex: E1 And E2 Substrate Specificty, E1 Carboligase Activity, And E2 Interchain Succinyl Transfer, Da Jeong Shim

Dissertations

Escherichia coli (E. coli) 2-oxoglutarate dehydrogenase multienzyme complex (OGDHc) contains three components: a thiamin di phosphate (ThD P) dependent 2-oxogl utarate dehydrogenase (E1 o), a di hydrol i poylsucci nyl transferase (E2o), and a di hydrol i poyl dehydrogenase (E3). The first two components carry out the principal reactions for succinyl CoA formation while the third one reoxidizes dihydrolipoamide to lipoamide. This mechanism is similar to other 2-oxoacid dehydrogenase complexes, including pyruvate dehydrogenases (PDHc) and branched-chain dehydrogenases.

E1o of the E. coli OGDHc was engineered to accept unnatural substrates. The natural substrate for E1 o is 2-oxogl utarate …

Computational Thermochemistry Of Hydrocarbons, Oxygenates, Cyclic Alkanes, And Furans, Jason Michael Hudzik

Dissertations

Fundamental thermochemical properties including enthalpies (ΔH°_{f 298}), entropies (S° (T)), heat capacities (C_p(T)), and bond dissociation energies (BDEs) for several common and complex hydrocarbon fuel species are determined using computational chemical methods. ΔH° _{f 298} values are calculated using work reactions with the B3LY P (6-31 G(d,p) and 6-311G(2d,2p) basis sets), CBS-QB3, and G3MP2B3 calculation methods. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated for contributions to entropies and heat capacities. Kinetic rate parameters are calculated for hydrogen abstraction and chemical activation reactions.

Recommended ΔH° …

Interactions Of Zn2+ On Insulin Oligomer Formation, Stability, And Fragmentation: Analysis Using Esi-Im-Ms, Tiffany Culver

Honors Theses

Insulin is a hormone protein essential to the regulation of blood sugar levels. Although it is active as a hormone in the monomer (single insulin unit) form, it is stored in the pancreas as a hexamer – a coordination of six insulin units and zinc ions. This research analyzes the effects of zinc ions on the formation, stability, and fragmentation of the hexamer and other oligomer species in varying solution and instrument conditions, including the ability of the higher oligomers to transfer from crystallization to solution to a gas phase for analysis using electrospray ionization ion mobility mass spectrometry (ESI-IM-MS). …

Photoionization Mass Spectrometry And Photoelectron-Photoion Coincidence (Pepico) Spectroscopy Studies Of Select Biofuel Molecules, Joseph G. Czekner

Master's Theses

This thesis is the culmination of numerous experiments, performed on two different continents, investigating the spectroscopic and thermodynamic properties of several biofuels and fuel additives. It will start with an introduction about the motivation behind these experiments. The second chapter will outline the experimental details of the apparatus at the Advanced Light Source (ALS) in Berkeley, CA, followed by the Swiss Light Source (SLS) in Villigen, Switzerland. Third, the theoretical concepts and data analysis methods will be discussed in detail.

Chapter 4 will be the start of the newly obtained data. It presents some photoionization mass spectrometry studies on γ-valerolactone …

Identification Of An Active Site-Bound Nitrile Hydratase Intermediate Through Single Turnover Stopped-Flow Spectroscopy, Natalie Gumataotao, Misty L. Kuhn, Natalia Hajnas, Richard C. Holz

Chemistry Faculty Research and Publications

Stopped-flow kinetic data were obtained for the iron-type nitrile hydratase from Rhodococcus equi TG328-2 (ReNHase) using methacrylonitrile as the substrate. Multiple turnover experiments suggest a three-step kinetic model that allows for the reversible binding of substrate, the presence of an intermediate, and the formation of product. Microscopic rate constants determined from these data are in good agreement with steady state data confirming that the stopped-flow method used was appropriate for the reaction. Single turnover stopped-flow experiments were used to identify catalytic intermediates. These data were globally fit confirming a three-step kinetic model. Independent absorption spectra acquired between 0.005 …

Surface Tethered Pamam Dendrimers On Controlled Pore Glass As Color Release Sensors For Phosphates, Chang Liu

Master's Theses

Poly(amidoamine) dendrimer (PAMAM) are highly branched macromolecules with reactive amine groups in their interior and exterior. PAMAM dendrimers were attached to controlled pore glass (CPG) surfaces in order to create new functionalized surfaces and used as platforms for UV-vis and fluorescent sensing of phosphate substrates via indicator displacement assays (IDA).

CPG surfaces were first modified with different sized PAMAM dendrimers (generation 3.0, 4.0, and 5.0), then reacted with two strong metal-chelators: aminofunctionalized terpyridine (synthesized from 2,2’:6’,2’’-terpyridine) and Nα-Nα-bis(carboxymethyl)-L-lysine (Lys-NTA). First of all, Cu(II) metal ion binding capacities were measured on the surfaces. Second, two terminal group density tests, amine assay …

The Cyclomodulin Cycle Inhibiting Factor (Cif) Alters Cullin Neddylation Dynamics, Tasha B. Toro, J. I. Toth, M. D. Petroski

Faculty and Staff Publications

The bacterial effector protein cycle inhibiting factor (CIF) converts glutamine 40 of NEDD8 to glutamate (Q40E), causing cytopathic effects and inhibiting cell proliferation. Although these have been attributed to blocking the functions of cullin-RING ubiquitin ligases, how CIF modulates NEDD8-dependent signaling is unclear. Here we use conditional NEDD8-dependent yeast to explore the effects of CIF on cullin neddylation. Although CIF causes cullin deneddylation and the generation of free NEDD8 Q40E, inhibiting the COP9 signalosome (CSN) allows Q40E to form only on NEDD8 attached to cullins. In the presence of the CSN, NEDD8 Q40E is removed from cullins more rapidly than …

Targeting Udp-Galactopyranose Mutases From Eukaryotic Human Pathogens, Karina Kizjakina, John J. Tanner, Pablo Sobrado

Chemistry Faculty Research & Creative Works

UDP-Galactopyranose mutase (UGM) is a unique flavin-dependent enzyme that catalyzes the conversion of UDPgalactopyranose (UDP-Galp) to UDP-galactofuranose (UDP-Galf). The product of this reaction is the precursor to Galf, a major component of the cell wall and of cell surface glycoproteins and glycolipids in many eukaryotic and prokaryotic human pathogens. The function of UGM is important in the virulence of fungi, parasites, and bacteria. Its role in virulence and its absence in humans suggest that UGM is an ideal drug target. Significant structural and mechanistic information has been accumulated on the prokaryotic UGMs; however, in the past few years the research …

Measuring Learning Gains In Chemical Education: A Comparison Of Two Methods, Thomas C. Pentecost, Jack Barbera

Peer Reviewed Articles

Evaluating the effect of a pedagogical innovation is often done by looking for a significant difference in a content measure using a pre−post design. While this approach provides valuable information regarding the presence or absence of an effect, it is limited in providing details about the nature of the effect. A measure of the magnitude of the pre−post change, commonly called learning gain, could provide this additional information to chemical education researchers. In this paper, we compare two methods of measuring learning gains using data from large-scale administrations of the Chemical Concepts Inventory at four universities. The intent of this …

Probing The Low Temperature Oxidation Of Furanic Biofuels, 2-Methyltetrahydrofuran And 2,5-Dimethylfuran, Utilizing Orthogonal Time-Of-Flight Mass Spectrometry Coupled To Synchrotron Radiation, Matthew Mcmanus

Master's Theses

Concern over natural resources and global climate shifts has increased the focus of sourcing transportation fuels from depleting oil wells to regenerative, biological based solutions. One avenue of biologically sourced fuel involves the extraction of C5 and C6 sugars from the woody, fibrous, and inedible plant materials, otherwise known as lignocellulosic biomass. These cellulosic sugars can be converted to target biofuels and biofuel additives like the furanic compounds, 2,5-dimethylfuran and 2-methylfuran. In this thesis, the low temperature oxidation of two compounds, 2,5-dimethylfuran and 2-methylfuran, are explored. These reactions were conducted at the Advanced Light Source in Berkeley, CA and used …

The Investigation Of Iron(Ii) Complexes And Their Catalytic Applications, Matthew Joseph Lenze

Dissertations

Several new η5-indenyl (Ind) complexes of iron featuring phosphinooxazoline (PHOX) ligands were synthesized and spectroscopically characterized and in a few cases structurally. The complexes were synthesized using phosphinooxazoline ligands and the corresponding iron precursor [Fe(η5-Ind) I(CO)2], yielding novel piano-stool iron complexes of the general formula [Fe(η5-Ind)(CO)(PHOX)]+ in 73% to 81% isolated yields. The complexes were tested for their efficacy in a carbon-carbon bond formation known as the Mukaiyama aldol reaction. The [Fe(η5-Ind)(CO)(PHOX)]+ complexes were capable of activating the carbonyl of aromatic aldehydes towards by attack 1-(tertbutyldimethylsilyloxy)-1-methoxyethene to form the expected silyl protected β-hydroxyesters. In these complexes, the η5-η3 haptotropic shift …

Nanomaterials For Biological Applications: Drug Delivery And Bio-Sensing, Hui Ma

LSU New Orleans Theses and Dissertations

The idea of utilizing nanomaterials in bio-related applications has been extensively practiced during the recent decades. Magnetic nanoparticles (MPs), especially superparamagnetic iron oxide nanoparticles have been demonstrated as promising candidates for biomedicine. A protective coating process with biocompatible materials is commonly performed on MPs to further enhance their colloidal and chemical stability in the physiological environment. Mesoporous hollow silica is another class of important nanomaterials that are extensively studied in drug delivery area for their ability to carry significant amount of guest molecules and release in a controlled manner.

In this study, different synthetic approaches that are able to produce …

Synthesis And Antifungal Evaluation Of Barbiturate Saponins And Progress Towards Cysteinyl Metal Peptides, Monika Madhav

LSU New Orleans Theses and Dissertations

Invasive fungal infections are a major threat to immune-compromised patients. There is a critical need to develop new antifungal agents because of increasing resistance to the common antifungal drugs.

In the first part of this dissertation, methods for preparation of novel barbiturate saponin as antifungals and their biological activities would be described. Barbiturates and steroidal saponins have shown remarkable antifungal activity in the biological assays. Therefore, attempts were directed to combine the barbiturate with the steroid to give novel antifungal agents. The need for extensive SAR studies and to better understand these compounds efforts were directed to synthesize novel saponin …

Isolation, Characterization And Synthesis Of Asthma Inducing Fungal Glycolipid And Analytical Method Development For Novel Antimicrobial Peptide Mimics, Vinod Chaudhary

Theses and Dissertations

NKT cells are an important part of human immune system and recognize a specific set of antigens called glycolipids. Only a handful of "natural" NKT cell antigens are known till date. Although NKT cells play a protective role against pathogenic organisms, imbalances in NKT cell functions are implicated in many diseases including asthma. Allergic asthma, a Th2 driven inflammation of airways, is primarily caused by inhalation of environmental allergens. In the last decade, inhaled allergen Aspergillus fumigatus has been under scrutiny for the presence of NKT cell antigens that might trigger asthma. We successfully isolated, characterized and synthesized a "natural" …

Synthesis And Immunological Evaluation Of Type I, Type Ii, And Gamma Delta Nkt Cell Antigens, Brian L. Anderson

Theses and Dissertations

The purpose of the immune system is to protect our bodies from infection. One way it accomplishes this task is through the presentation of foreign pathogens to NKT cells. After an antigen is presented to the T cell receptor, activated NKT cells quickly release soluble chemical signals, termed chemokines and cytokines, that modulate the response of the immune system. Due to the immunological relevance of NKT cell activation, we developed and synthesised non-natural analogs of immunostimulatory type I, II, and gamma delta NKT cell antigens. The immunological evaluations of these analogs resulted in identification of sulfatide as a gamma delta …

Label-Free Detection Of Low Protein Concentration In Solution Using A Novel Colorimetric Assay, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Dual pH and temperature sensitive microgel-based etalons were fabricated by sandwiching a “monolithic” microgel layer between two semitransparent, Au layers. The devices exhibit visual color and multipeak reflectance spectra, both of which primarily depend on the distance between the Au surfaces mediated by the microgel diameter. We found that a polycationic polyelectrolyte can penetrate through the Au overlayer to interact with negatively charged microgel confined between Au overlayers. In this submission we report that biotinylated polycationic polymer can penetrate through the Au overlayer of a poly (N-isopropylacrylamide)-co-acrylic acid (pNIPAm-co-AAc) microgel-based etalon and cause the microgel layer to collapse. The collapse …

Exploring Freshmen College Students' Self-Efficacy, Attitudes, And Intentions Toward Chemistry, Amanda F. Cook

Mahurin Honors College Capstone Experience/Thesis Projects

This study examined the self-efficacy beliefs, attitudes towards general chemistry, and intentions to take future chemistry courses in a sample of (n = 1,126) first-time, first-year freshmen from a large comprehensive university in the Mid-South. The main purpose of the study was to determine the amount of variance in students’ intentions which could be predicted by self-efficacy, attitudes, and other known influences (past performance, past experience and choice of major). Findings from a standard multiple regression indicate that self-efficacy (β = 0.07, p < .05) and attitude (β = 0.50, p < .001) are both significant and predict 29.3% of the variance in intentions, with attitudes making a larger unique contribution. Using a hierarchical regression to control for other known factors, self-efficacy and attitudes were still able to predict 23.5% of the variance in intentions. Overall, the five independent variables were able to predict 31.7% of the variance in intentions. Implications for secondary and postsecondary science educators and STEM administrators are discussed.

A New Class Of Gold Nanoantibotics - Direct Coating Of Ampicillin On Gold Nanoparticles, Dillon S. Pender

Mahurin Honors College Capstone Experience/Thesis Projects

Need for novel, innovative strategies for developing antibiotics is becoming a necessity due to an increasing number of rapidly evolving micro-organismal threats. Antibiotic encapsulated gold nanoparticles (GNPs) are one such strategy showing promise. We report the development of ampicillin encapsulated gold nanoparticles (Amp-GNPs) that possess highly effective, dose dependant antibacterial activity. In this method, ampicillin molecules have been coated on individual GNPs which can then serve as drug carrier devices. Our method for synthesizing Amp-GNPs is an entirely ecofriendly, single step reaction taking place in an aqueous buffer. Following characterization of Amp-GNPs, we find them to be ~15 nm in …

Differential Hydrogen Bonding In Human Cyp17 Dictates Hydroxylation Versus Lyase Chemistry, Michael Gregory, Piotr J. Mak, Stephen G. Sligar, James R. Kincaid

Chemistry Faculty Research and Publications

Consequences of alternative H-bonding: Raman spectra of oxygenated intermediates of Nanodisc-incorporated human CYP17 in the presence of natural substrates (pregnenolone and progesterone) directly confirm that substrate structure effectively alters hydrogen-bonding interactions with the critical Fe–O–O fragment and dictates its predisposition for one of two alternative reaction pathways. Such substrate control has profound physiological implications.

Training An Asymmetric Signal Perceptron In An Artificial Chemistry, Peter Banda

Student Research Symposium

Autonomous learning implemented purely by means of a synthetic chemical system has not been previously realized. Learning promotes reusability, and minimizes the system design to simple input-output specification. In this poster, I present a simulated chemical system, the first full-featured implementation of a perceptron in an artificial (simulated) chemistry, which can successfully learn all 14 linearly separable logic functions. A perceptron is the simplest system capable of learning inspired by the functioning of a biological neuron. My newest model called the asymmetric signal perceptron (ASP) is, as opposed to its predecessors such as the weight-race perceptron (WRP), substantially simpler by …

Microglial Activation By Amyloid-Beta, Geeta Subhash Paranjape

Dissertations

Paranjape, Geeta S.,Ph.D.,University of Missouri-Saint Louis, May 2012. Aβ(1-42) Protofibrils But Not Fibrils Activate Microglia. Major Professor: Michael R. Nichols. One of the hallmark features of the Alzheimer’s disease (AD) brain is the extracellular deposition of amyloid-β protein (Aβ) in both fibrillar (senile plaques) and diffuse forms. Significant proinflammatory markers including activated microglia and cytokines have been detected surrounding the plaques but are absent in diffuse areas suggesting that microglial activation is sensitive to Aβ structure. Since Aβ displays structural polymorphism in vitro, we sought to determine the relationship between Aβ aggregation state and microglial proinflammatory response. Size exclusion chromatography …

Binding Energies And Solvation Of Organic Molecular Ions, Reactions Of Transition Metal Ions With, And Plasma Discharge Ionization Of Molecular Clusters, Isaac Kwame Attah

Theses and Dissertations

In this dissertation, different approaches have been employed to address the quest of understanding the formation and growth mechanisms of carbon-containing molecular ions with relevance to astrochemistry. Ion mobility mass spectrometry and DFT computations were used to investigate how a second nitrogen in the pyrimidine ring will affect the formation of a covalent bond between the benzene radical cation and the neutral pyrimidine molecule, after it was shown that a stable covalent adduct can be formed between benzene radical cation and the neutral pyridine. Evidence for the formation of a more stable covalent adduct between the benzene radical cation and …

I. Stereochemical Control Of Chiral Assembly And Liquid Crystal Phase Formation Of Nonamphiphilic Molecules In Water Ii. Control Bacterial Quorum Sensing And Quorum Sensing-Mediated Activities Using Small Unnatural Molecules, Sijie Yang

Chemistry - Dissertations

The primary goal of this research is to utilize organic synthesis as a tool to prepare small molecules that find potential application in different areas including colloidal and material science, biological chemistry, and medicinal chemistry.

Chapter 1 describes the interpretation of the conformation of nonamphiphilic mesogen disodium cromoglycate (5´DSCG) when it exists as part of an assembly in water. The study of thermodynamic incompatibility and miscibility suggest that a previously proposed model for the assembly of 5´DSCG may be applicable to nonamphiphilic organic dyes and other mesogens.

Chapter 2 presents a study of stereochemical control on assembly and liquid crystal …

Synthesis Of Rhenium And Manganese Pyridazoal Complexes, Jesse Evans

Masters Theses & Specialist Projects

Pyridazines are a heterocyclic aromatic compound containing a characteristic N-N bond that are utilized in many fields, including medicine and electronics. It is this latter field that Dr. Snyder's research group is focused upon. Organometallic compounds are a better conducting material than the current inorganic compounds used in electronics due to better conductance of electricity, lower production cost, and the ability to be formed into thin films. With this in mind, Dr. Snyder's research group has set out to synthesize organometallic compounds for this purpose. Following procedures set forth by Snyder etc, and altered to form an off-metal route, we …