Chemistry Commons^™

Contribution Of New Thiol Antioxidant In The Treatment Of Acetaminophen Toxicity, Ahdab Naeem Khayyat

Doctoral Dissertations

"Acetaminophen (N-acetyl-p-aminophenol, APAP) is one of the most widely used over-the-counter antipyretic analgesic medications. It is safe at therapeutic doses, but an overdose can result in severe hepato-nephrotoxicity, a leading cause of drug-induced acute liver failure in the U.S. Although a few different mechanisms have been proposed for APAP-induced toxicity, a significant amount of evidence has pointed to the potential involvement of oxidative stress in acetaminophen toxicity. Depletion of glutathione (GSH) is one of the initiating steps in APAP-induced toxicity; therefore, one strategy for restricting organ damage is to restore GSH levels by using GSH prodrugs like N-acetylcysteine (NAC). Although …

Synthesis And Functionalization Of A Triaryldiamine-Base Photoconductive/Photorefractive Composite, And Its Application To Aberrated Image Restoration, Yichen Liang

Doctoral Dissertations

"Organic photorefractive (PR) composites have recently emerged as an important class of materials for applications including high-density data storage, optical communication, and biomedical imaging. In an effort to further improve their performance, this study focused on the utilization of functionalized semiconductor nanocrystals to photosensitize triaryamine (TPD)-based PR composites, as well as the application of TPD-based PR composites in the restoration of aberrated optical information. A novel approach to functionalize CdSe quantum dot (QCdSe) was firstly introduced where the sulfonated triarydiamine (STPD) was used as charge-transporting ligand to passivate QCdSe. TPD-based photoconductive and PR composites were photosensitized with the STPD-passivated QCdSe …

Construction Of Multi-State Potential Energy Surfaces For Spectroscopy And Dynamics, Phalgun Lolur

Doctoral Dissertations

"This dissertation is about construction and visualization of multi-state Born-Oppenheimer potential energy surfaces which are essential for studying spectroscopy and dynamics. A potential energy surface is a mathematical function that represents the energy of a system as a function of its molecular geometry. The Born-Oppenheimer approximation enables us to solve the Schrödinger equation by separating the nuclear and electronic motions. Construction of potential energy surfaces has become a basic and crucial operation for chemists in order to compute various electronic states of molecules for understanding the spectroscopy, kinetics and dynamics of molecules. These methods have been used to successfully (i) …

Polyacrylamide And Its Derivatives For Oil Recovery, Zun Chen

Doctoral Dissertations

"Polyacrylamide is an umbrella term used to describe the homo-polymer of acrylamide and the copolymer of acrylamide with a small amount of other monomers. Owing to their superior property on increasing viscosity and gelling ability in the presence of crosslinkers, polyacrylamides has become the primarily selection for polymer flooding and gel treatment agent in enhanced oil recovery. Recent developments, performance, applications and limitations of polyacrylamides and its derivatives, including copolymers and hydrogels for enhancing oil recovery are reviewed.

A water-free suspension system was developed to synthesize PAMs and PAMs-microgel. Products are dry particle powder and ready to disperse in water. …

Functional Nanoporous Polyamide Aerogels, Malik Adnan Saeed

Doctoral Dissertations

"Aerogels are low-density materials consisting of 3D assemblies of nanoparticles with high open porosities and surface areas. Inspired by the extraordinary mechanical strength of polymer crosslinked aerogels, our recent attention is focused on inexpensive multifunctional isocyanates reacting with a variety of aromatic, organometallic and inorganic monomers. Three such systems discussed here are:

(A) Polymeric aerogels synthesized via a room temperature reaction of an aromatic triisocyanate with pyromellitic acid. Using solid-state CPMAS ¹³C and ¹⁵N NMR, it was found that the skeletal framework was a statistical co-polymer of polyamide, polyurea and polyimide. Stepwise pyrolytic decomposition followed by reactive etching …

New Polyanion-Based Cathode Materials For Alkali-Ion Batteries, Hooman Yaghoobnejad Asl

Doctoral Dissertations

"A number of new materials have been discovered through exploratory synthesis with the aim to be studied as the positive electrode (cathode) in Li-ion and Na-ion batteries. The focus has been set on the ease of synthesis, cost and availability of active ingredients in the battery, and decent cycle-life performance through a combination of iron and several polyanionic ligands. An emphasis has been placed also on phosphite (HPO₃^2-) as a polyanionic ligand, mainly due to the fact that it has not been studied seriously before as a polyanion for cathode materials. The concept of mixed polyanions, for …

Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan

Doctoral Dissertations

"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …

Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang

Doctoral Dissertations

"Manufactured nano-/micro-materials (MNMs) have been widely used and their interactions with niche biological environment are highly concerned for both of their biohazardous and bioactive effects, whereas no available comprehensive evaluations or regulations have been provided yet. This dissertation thus focuses on three major aspects: 1) fundamental toxicity understandings of a typical MNMs (zinc oxide nanoparticles), 2) bioactivity evaluations of representative bioactive MNMs, and 3) development of novel micro-probes for high spatial resolution monitoring. Firstly, the NP's concentration, irradiation, hydrodynamic size, and the localized pH, ionic strength, NP zeta-potential as well as dissolved oxygen levels were found correlated with the production …

Liposomal Delivery Of Pde5 Inhibitors And Ut-15c To Human Erythrocytes, Elizabeth Anne Bowles

Doctoral Dissertations

"Previous studies have shown that the controlled release of adenosine triphosphate (ATP) from human erythrocytes is an important mechanism for the regulation of vascular caliber. However, erythrocytes from patients with pulmonary arterial hypertension (PAH) fail to release ATP in response to the physiological stimuli of exposure to low oxygen tension or mechanical deformation of a magnitude these cells would encounter in the pulmonary circulation. This defect could be a significant contributor to the increased pulmonary vascular resistance (PVR) that is the cause of the pathological increase in vascular pressures in humans with PAH.

One important approach to the treatment of …

Method And Apparatus For Cancer Screening, Yinfa Ma, Stephen Gibbons

Chemistry Faculty Research & Creative Works

A method and apparatus for detection of pteridine levels in a biological sample using CE-LIF which is useful for early cancer screening involving fully oxidizing pteridine compounds in a sample such as a urine sample, subjecting to CE-LIF to assess compound concentration, and compare to expected levels in for healthy or cancer-bearing patients.

Assessing The Accuracy Of Some Popular Dft Methods For Computing Harmonic Vibrational Frequencies Of Water Clusters, J. Coleman Howard, Jordan D. Enyard, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A wide range of density functional theory (DFT) methods (37 altogether), including pure, hybrid, range-separated hybrid, double-hybrid, and dispersion-corrected functionals, have been employed to compute the harmonic vibrational frequencies of eight small water clusters ranging in size from the dimer to four different isomers of the hexamer. These computed harmonic frequencies have been carefully compared to recently published benchmark values that are expected to be very close to the CCSD(T) complete basis set limit. Of the DFT methods examined here, ωB97 and ωB97X are the most consistently accurate, deviating from the reference values by less than 20 cm^-1 on …

Functionalized Nanodiamond Reinforced Biopolymers, Gongyao Zhou, Peter I. Lelkes, Yury Gogotsi, Vadym Mochalin

Chemistry Faculty Research & Creative Works

The present invention includes a composition for implantation in a patient, comprising surface-functionalized nanodiamonds and at least one biodegradable biocompatible polymer. The present invention also includes a surgical fixation device for use in a patient.

Biomaterial Compositions, Kathleen V. Kilway, Lynda F. Bonewald, Thomas P. Schuman

Chemistry Faculty Research & Creative Works

Biomaterial compositions comprising organosilicon monomers (such as silorane monomers) and chemical curing systems or dual chemical/light curing systems, in conjunction with optional tetraoxaspiro[5.5]undecanes (“TOSUs”) and/or fillers. The present invention is directed to biomaterial compositions, as well as methods for manufacturing the same, and methods of using the compositions. The biomaterial composition comprises one or more organosilicon monomers (such as a silorane) and a chemical curing system or dual chemicaVlight curing system for polymerizing the 10 monomer(s). The compositions may include one or more tetraoxaspiro[5.5]undecanes “TOSUs”) and/or fillers. Accelerators (such as photoacids), photosensitizers, and/or electron donors may also be included in …

An Electrodeposited Inhomogeneous Metal-Insulator-Semiconductor Junction For Efficient Photoelectrochemical Water Oxidation, James C. Hill, Alan T. Landers, Jay A. Switzer

Chemistry Faculty Research & Creative Works

The photoelectrochemical splitting of water into hydrogen and oxygen requires a semiconductor to absorb light and generate electron-hole pairs, and a catalyst to enhance the kinetics of electron transfer between the semiconductor and solution. A crucial question is how this catalyst affects the band bending in the semiconductor, and, therefore, the photovoltage of the cell. We introduce a simple and inexpensive electrodeposition method to produce an efficient n-Si/SiOx/Co/CoOOH photoanode for the photoelectrochemical oxidation of water to oxygen. The photoanode functions as a solid-state, metal-insulator-semiconductor photovoltaic cell with spatially non-uniform barrier heights in series with a low overpotential water-splitting electrochemical cell. …

Real-Time Supervised Detection Of Pink Areas In Dermoscopic Images Of Melanoma: Importance Of Color Shades, Texture And Location, Ravneet Kaur, P. P. Albano, Justin G. Cole, Jason R. Hagerty, Robert W. Leander, Randy Hays Moss, William V. Stoecker

Electrical and Computer Engineering Faculty Research & Creative Works

Background/Purpose: Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits.

Methods: Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue, and saturation). Color shade analysis was performed using a logistic …

Water Network-Mediated, Electron-Induced Proton Transfer In [C5h5n·(H2o)N]⁻ Clusters, Andrew F. Deblase, Conrad T. Wolke, Gary H. Weddle, Kaye A. Archer, Kenneth D. Jordan, John T. Kelly, Gregory S. Tschumper, Nathan I. Hammer, Mark A. Johnson

Chemistry Faculty Research & Creative Works

The role of proton-assisted charge accommodation in electron capture by a heterocyclic electron scavenger is investigated through theoretical analysis of the vibrational spectra of cold, gas phase [Py·(H₂O) _n=3-5]^- clusters. These radical anions are formed when an excess electron is attached to water clusters containing a single pyridine (Py) molecule in a supersonic jet ion source. Under these conditions, the cluster ion distribution starts promptly at n = 3, and the photoelectron spectra, combined with vibrational predissociation spectra of the Ar-tagged anions, establish that for n > 3, these species are best described as hydrated hydroxide ions …

Synergistic Effects Of Halogen Bond And Π-Π Interactions In Thiophene-Based Building Blocks, Jamey Wilson, Jon Steven Dal Williams, Chesney Petkovsek, Peyton Reves, Jonah W. Jurss, Nathan I. Hammer, Gregory S. Tschumper, Davita L. Watkins

Chemistry Faculty Research & Creative Works

Although recognized as a significant force in crystal engineering, halogen bonding (XB) has been scarcely investigated in "bottom-up" approaches towards organic electronics. We report, herein, the use of a thiophene-based building block, pyridyl-thiophene (Pyr-T), to achieve an assembly driven by XB and π-π stacking interactions with iodopentafluorobenzene (IPFB). Spectroscopic and thermal analysis of the co-crystal provide indirect evidence of the assembly. The combined effects of XB and π-π stacking are confirmed experimentally via X-ray crystallography. Density functional theory (DFT) computations support experimental observations. The results of the study speak to the use of halogen bond driven self-assembly in organic electronic …

Generalized Synthesis Of Eas [E = Fe, Co, Mn, Cr] Nanostructures And Investigating Their Morphology Evolution, Prachi Desai, Nikitaa Ashokan, Manashi Nath

Chemistry Faculty Research & Creative Works

This paper illustrates a novel route for the synthesis of nanostructured transition metal arsenides including those of FeAs, CoAs, MnAs, and CrAs through a generalized protocol. The key feature of the method is the use of one-step hot-injection and the clever use of a combination of precursors which are low-melting and highly reactive such as metal carbonyls and triphenylarsine in a solventless setup. This method also facilitates the formation of one-dimensional nanostructures as we move across the periodic table from CrAs to CoAs. The chemical basis of this reaction is simple redox chemistry between the transition metals, wherein the transition …

X-Ray Structure Of A Mammalian Stearoyl-Coa Desaturase, Yonghong Bai, Jason G. Mccoy, Elena J. Levin, Pablo Sobrado, Kanagalaghatta R. Rajashankar, Brian G. Fox, Ming Zhou

Chemistry Faculty Research & Creative Works

Stearoyl-CoA desaturase (SCD) is conserved in all eukaryotes and introduces the first double bond into saturated fatty acyl-CoAs. Because the monounsaturated products of SCD are key precursors of membrane phospholipids, cholesterol esters and triglycerides, SCD is pivotal in fatty acid metabolism. Humans have two SCD homologues (SCD1 and SCD5), while mice have four (SCD1-SCD4). SCD1-deficient mice do not become obese or diabetic when fed a high-fat diet because of improved lipid metabolic profiles and insulin sensitivity^5,6. Thus, SCD1 is a pharmacological target in the treatment of obesity, diabetes and other metabolic diseases⁷. SCD1 is an integral …

Vibrational Energy Levels Of The Simplest Criegee Intermediate (Ch₂Oo) From Full-Dimensional Lanczos, Mctdh, And Multimode Calculations, Hua-Gen Yu, Steve Alexandre Ndengué, Jun Li, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

Accurate vibrational energy levels of the simplest Criegee intermediate (CH₂OO) were determined on a recently developed ab initio based nine-dimensional potential energy surface using three quantum mechanical methods. the first is the iterative Lanczos method using a conventional basis expansion with an exact Hamiltonian. the second and more efficient method is the multi-configurational time-dependent Hartree (MCTDH) method in which the potential energy surface is refit to conform to the sums-of-products requirement of MCTDH. Finally, the energy levels were computed with a vibrational self-consistent field/virtual configuration interaction method in MULTIMODE. the low-lying levels obtained from the three methods are …

New Potential Energy Surface For The Hcs⁺-He System And Inelastic Rate Coefficients, Marie-Lise Dubernet, Ernesto Quintas-Sánchez, Philip Tuckey

Chemistry Faculty Research & Creative Works

A new high quality potential energy surface is calculated at a coupled-cluster single double triple level with an aug-cc-pV5Z basis set for the HCS⁺-He system. This potential energy surface is used in low energy quantum scattering calculations to provide a set of (de)-excitation cross sections and rate coefficients among the first 20 rotational levels of HCS⁺ by He in the range of temperature from 5 K to 100 K. The paper discusses the impact of the new ab initio potential energy surface on the cross sections at low energy and provides a comparison with the HCO^{+ …}

Erratum: "H2 - Agcl: A Spectroscopic Study Of A Dihydrogen Complex" (Journal Of Chemical Physics 141:114306 (2014)), Garry S. Grubbs, Daniel A. Obenchain, Herbert M. Pickett, Stewart E. Novick

Chemistry Faculty Research & Creative Works

No abstract provided.

Acoustic Attenuators Based On Porous Nanostructured Materials, Hongbing Lu, Ning Xiang, Nicholas Leventis, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

The invention is directed to a porous, acoustic attenuating composition, wherein the composition comprises a nanostructured material and wherein the composition exhibits acoustic transmission loss ranging from 20 to 60 dB/cm thickness of the composition.

Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott A. Reid, Phalgun Lolur, Richard Dawes

Chemistry Faculty Research & Creative Works

We report a global analysis of spin-orbit coupling in the mono-halocarbenes, CH(D)X, where X = Cl, Br, and I. These are model systems for examining carbene singlet-triplet energy gaps and spin-orbit coupling. Over the past decade, rich data sets collected using single vibronic level emission spectroscopy and stimulated emission pumping spectroscopy have yielded much information on the ground vibrational level structure and clearly demonstrated the presence of perturbations involving the low-lying triplet state. To model these interactions globally, we compare two approaches. First, we employ a diabatic treatment of the spin-orbit coupling, where the coupling matrix elements are written in …

An Unprecedented Nadph Domain Conformation In Lysine Monooxygenase Nbtg Provides Insights Into Uncoupling Of Oxygen Consumption From Substrate Hydroxylation, Claudia Binda, Reeder M. Robinson, Julia S. Martin Del Campo, Nicholas D. Keul, Pedro J. Rodriguez, Howard H. Robinson, Andrea Mattevi, Pablo Sobrado

Chemistry Faculty Research & Creative Works

N-Hydroxylating monooxygenases are involved in the biosynthesis of iron-chelating hydroxamate-containing siderophores that play a role in microbial virulence. These flavoenzymes catalyze the NADPH-and oxygen-dependent hydroxylation of amines such as those found on the side chains of lysine and ornithine. In this work we report the biochemical and structural characterization of Nocardia farcinica Lys monooxygenase (NbtG), which has similar biochemical properties to mycobacterial homologs. NbtG is also active on D-Lys, although it binds L-Lys with a higher affinity. Differently from the ornithine monooxygenases PvdA, SidA, and KtzI, NbtG can use both NADH and NADPH and is highly uncoupled, producing more superoxide …

Benchmark Structures And Harmonic Vibrational Frequencies Near The Ccsd(T) Complete Basis Set Limit For Small Water Clusters: (H2o)N = 2, 3, 4, 5, 6, J. Coleman Howard, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

A series of (H₂O)_n clusters ranging from the dimer to the hexamer have been characterized with the CCSD(T) and the 2-body: Many-body CCSD(T):MP2 methods near the complete basis set (CBS) limit to generate benchmark-quality optimized structures and harmonic vibrational frequencies for these important systems. Quadruple-ζ correlation-consistent basis sets that augment the O atoms with diffuse functions have been employed in the analytic computation of harmonic vibrational frequencies for the global minima of the dimer, trimer, tetramer, and pentamer as well as the ring, book, cage, and prism isomers of the hexamer. Prior calibration [J. Chem. Phys. 2013, …

Kinetic Isotope Effect Of The ¹⁶O+³⁶O₂ And ¹⁸O+³²O₂ Isotope Exchange Reactions: Dominant Role Of Reactive Resonances Revealed By An Accurate Time-Dependent Quantum Wavepacket Study, Zhigang Sun, Dequan Yu, Wenbo Xie, Jiayi Hou, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

The O + O₂ isotope exchange reactions play an important role in determining the oxygen isotopic composition of a number of trace gases in the atmosphere, and their temperature dependence and kinetic isotope effects (KIEs) provide important constraints on our understanding of the origin and mechanism of these and other unusual oxygen KIEs important in the atmosphere. This work reports a quantum dynamics study of the title reactions on the newly constructed Dawes-Lolur-Li-Jiang-Guo (DLLJG) potential energy surface (PES). The thermal reaction rate coefficients of both the 18O + 32O₂ and 16O + 36O₂ reactions obtained using the …

Growth Of Ordered Nanostructure Arrays Including Nanotubes And Nanorods For High Efficiency Solar Cells, Wipula P. Liyanage, Manashi Nath

Chemistry Faculty Research & Creative Works

A simple and straightforward approach has been described for the fabrication of CdTe nanotube and nanorod arrays with a high degree of precision through confined electrodeposition on lithographically patterned nanoelectrodes. This technique has the potential of growing these nanotube/nanowire arrays with extreme uniformity over a significantly large area. the desired nanoelectrode pattern was defined through electron beam lithography on indium tin oxide coated glass, and electrodeposition of the semiconducting material of interest (CdTe) on the nanoelecrodes produced the nanotubes/nanowires. It is interesting to note that the measured photocurrent density of nanotube device created by this protocol exceeds that obtained from …

Boyd Group Electronegativity Influence On The Parr Global Electrophilicity Of Vilsmeier Reagent-Derived Imidates: New Insights Toward Improving Mitsunobu Chemistry, Jeremy M. Carr, Gregory S. Tschumper, A. Paige Lathem

Chemistry Faculty Research & Creative Works

Reactivities of 19 methylated imidate analogs were examined using B3LYP and M06-2X DFT methods. The resulting HOMO and LUMO energies of each optimized structure were used to calculate corresponding Parr global electrophilicity (ω) values. When the resulting quantities were compared against Boyd group electronegativity (X_G) values, a clear correlation was observed, suggesting that electron-withdrawing effects influence the reactivity of imidates. These findings represent an important first step in developing a novel method toward improving traditional Mitsunobu functionalization reactions.

Indolizine-Based Donors As Organic Sensitizer Components For Dye-Sensitized Solar Cells, Aron J. Huckaba, Fabrizio Giordano, Louis E. Mcnamara, Katelyn M. Dreux, Nathan I. Hammer, Gregory S. Tschumper, Shaik M. Zakeeruddin, Michael Grätzel, Mohammad K. Nazeeruddin, Jared H. Delcamp

Chemistry Faculty Research & Creative Works

Strong electron-donating functionality is desirable for many organic donor-π-bridge-acceptor (D-π-A) dyes. Strategies for increasing the electron-donating strength of common nitrogen-based donors include planarization of nitrogen substituents and the use of low resonance-stabilized energy aromatic ring-substituted nitrogen atoms. Organic donor motifs based on the planar nitrogen containing heterocycle indolizine are synthesized and incorporated into dye-sensitized solar cell (DSC) sensitizers. Resonance active substitutions at several positions on indolizine in conjugation with the D-π-A π-system are examined computationally and experimentally. The indolizine-based donors are observed to contribute electron density with strengths greater than triarylamines and diarylamines, as evidenced by UV/Vis, IR absorptions, and …