Chemistry Commons^™

Improved Partial Charge Models In Siliceous Zeolites For The Simulation Of Adsorption And Identification Of Catalytic Sites, Jarod J. Wolffis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Utilization of computational modelling and simulation is expanding as computer processing power has increased and as new tools have been developed. This thesis focuses on efforts to improve the accuracy of simulations in aluminosilicate zeolites, an industrially important category of materials for catalysis and separations. For these sorbents, partial atomic charge represents a critical parameter in molecular mechanics simulations, determining the Coulombic non-bonding interaction. Partial charges may also be used as a measure of important physical parameters of the system such as the degree of covalency or the relative acidity of catalytic sites. We compare several common methods for predicting …

Ismar / Rmcmr 2017 Abstract Book - Joint Conference Of The International Society Of Magnetic Resonance, The Rocky Mountain Conference On Epr, And The Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Abstracts from the 59th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, hosted jointly with the International Society of Magnetic Resonance and the Rocky Mountain Conference on EPR. Held in Quebec City, Canada, July 23-28, 2017.

Level Lifetimes And The Structure Of 134Xe From Inelastic Neutron Scattering, Erin E. Peters, Anagha Chakraborty, Benjamin P. Crider, S. F. Ashley, E. Elhami, S. F. Hicks, A. Kumar, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, Francisco M. Prados-Estévez, Steven W. Yates

Chemistry Faculty Publications

The level structure of ¹³⁴Xe was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0⁺ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3⁻ octupole phonon has been confirmed, and the complete negative-parity multiplet …

Graphene-Based ‘Hybrids’ As High-Performance Electrodes With Tailored Interfaces For Alternative Energy Applications: Synthesis, Structure And Electrochemical Properties, Mayme Marie Van Meveren

Masters Theses & Specialist Projects

Technological progress is determined to a great extent by developments of novel materials from new combinations of known substances with different dimensionality and functionality. We investigate the development of 3D ‘hybrid’ nanomaterials by utilizing graphene based systems coupled with transition metal oxides (e.g. manganese oxides MnO2 and Mn3O4). This lays the groundwork for high performance electrochemical electrodes for alternative energy owing to their higher specific capacitance, wide operational window and stability through charge-discharge cycling, environmental benignity, cost effective, easily processed, and reproducible in a larger scale.

Thus far, very few people have investigated the potential of combining carbon sheets that …

Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu

Dissertations (1934 -)

Cytochrome P450 is a broad class of heme monooxygenase enzymes which catalyze various oxidative transformations. There are two main kinds of mammalian P450s: steroidogenic and drug metabolizing P450s. The first project involves a steroidogenic P450, CYP17A1, occupying a central role in the biosynthesis of steroid hormones. It catalyzes hydroxylation reaction on pregnenolone and progesterone, generating 17OH-pregnenolone and 17OH-progesterone, presumably utilizing a “Compound I” species. However, these hydroxylated products can be further processed in a second oxidative cycle to cleave the C17–C20 bond to form dehydroepiandrosterone or androstenedione, respectively, a crucial step in androgen production. Interestingly, it is well known that …

Formulation, Characterisation And Stability Assessment Of A Food Derived 1 Tripeptide, Leucine-Lysine-Proline Loaded Chitosan Nanoparticles, Minna Khalid Danish, Giuliana Vozza, Hugh Byrne, Jesus Maria Frias, Sinead Ryan

Articles

The chicken or fish derived tripeptide, Leucine-Lysine-Proline (LKP), inhibits the Angiotensin Converting Enzyme and may be used as an alternative treatment for pre-hypertension. However, it has low permeation across the small intestine. The formulation of LKP into a nanoparticle (NP) has the potential to address this issue. LKP-loaded NPs were produced using an ionotropic gelation technique, using chitosan (CL113). Following optimisation of unloaded NPs, a mixture amount design was constructed using variable concentration of CL113 and tripolyphosphate at a fixed LKP concentration. Resultant particle sizes ranged from 120-271 nm, zeta potential values from 29-37 mV and polydispersity values from 0.3-0.6. …

Ionic Thermoelectric Paper, Fei Jiao, Ali Naderi, Dan Zhao, Joshua Schlueter, Maryam Shahi, Jonas Sundström, Hjalmar Granberg, Jesper Edberg, Ujwala Ail, Joseph W. Brill, Tom Lindström, Magnus Berggren, Xavier Crispin

Physics and Astronomy Faculty Publications

Ionic thermoelectric materials, for example, polyelectrolytes such as polystyrene sulfonate sodium (PSSNa), constitute a new class of materials which are attracting interest because of their large Seebeck coefficient and the possibility that they could be used in ionic thermoelectric SCs (ITESCs) and field effect transistors. However, pure polyelectrolyte membranes are not robust or flexible. In this paper, the preparation of ionic thermoelectric paper using a simple, scalable and cost-effective method is described. After a composite was fabricated with nanofibrillated cellulose (NFC), the resulting NFC–PSSNa paper is flexible and mechanically robust, which is desirable if it is to be used in …

Photopolymerization Synthesis Of Magnetic Nanoparticle Embedded Nanogels For Targeted Biotherapeutic Delivery, Daniel Jonwal Denmark

USF Tampa Graduate Theses and Dissertations

Conventional therapeutic techniques treat the patient by delivering a biotherapeutic to the entire body rather than the target tissue. In the case of chemotherapy, the biotherapeutic is a drug that kills healthy and diseased cells indiscriminately which can lead to undesirable side effects. With targeted delivery, biotherapeutics can be delivered directly to the diseased tissue significantly reducing exposure to otherwise healthy tissue. Typical composite delivery devices are minimally composed of a stimuli responsive polymer, such as poly(N-isopropylacrylamide), allowing for triggered release when heated beyond approximately 32 °C, and magnetic nanoparticles which enable targeting as well as provide a mechanism for …

Neutron Scattering Cross Section Measurements For 56Fe, Anthony Paul D. Ramirez, J. Vanhoy, S. F. Hicks, Marcus T. Mcellistrem, Erin E. Peters, Sharmistha Mukhopadhyay, T. D. Harrison, T. J. Howard, D. T. Jackson, P. D. Lenzen, T. D. Nguyen, R. L. Pecha, B. G. Rice, B. K. Thompson, Steven W. Yates

Chemistry Faculty Publications

Elastic and inelastic differential cross sections for neutron scattering from ⁵⁶Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C₆D₆ liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the TALYS and EMPIRE nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe …

Industrial Grade 2d Molybdenum Disulphide (Mos2): An In-Vitro Exploration Of The Impact On Cellular Uptake, Cytotoxicity, And Inflammation, Caroline Moore, Hugh Byrne, Jonathan N. Coleman, Yuri Volkov, Jennifer Mcintyre

Articles

The recent surge in graphene research, since its liquid phase monolayer isolation and characterization in 2004, has led to advancements which are accelerating the exploration of alternative 2D materials such as molybdenum disulphide (MoS2), whose unique physico-chemical properties can be exploited in applications ranging from cutting edge electronic devices to nanomedicine. However, to assess any potential impact on human health and the environment, the need to understand the bio-interaction of MoS2 at a cellular and sub-cellular level is critical. Notably, it is important to assess such potential impacts of materials which are produced by large scale production techniques, rather than …

Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, Tzucheng Wu

Physics & Astronomy ETDs

This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions …

Spectroscopy And Formation Of Lanthanum-Hydrocarbon Radicals Formed By C—C Bond Cleavage And Coupling Of Propene, Dilrukshi C. Hewage, Wenjin Cao, Sudesh Kumari, Ruchira Silva, Tao Hong Li, Dong-Sheng Yang

Chemistry Faculty Publications

La reaction with propene is carried out in a laser-vaporization molecular beam source. Three La-hydrocarbon radicals are characterized by mass-analyzed threshold ionization (MATI) spectroscopy. One of these radicals is methylenelanthanum [La(CH₂)] (C_s), a Schrock-type metal carbene. The other two are a five-membered 1-lanthanacyclopent-3-en [La(CH₂CHCHCH₂)] (C_s) and a tetrahedron-like trimethylenemethanelanthanum [La(C(CH₂)₃)] (C_3v). Adiabatic ionization energies and metal-ligand stretching and hydrocarbon-based bending frequencies of these species are measured from the MATI spectra, preferred structures and electronic states are identified by comparing the experimental measurements and spectral …

Silver Nanoparticles As A Potential Solar Absorber, Benjamin Hardy

Honors Projects

This work reports the development of Silver nanoparticles implanted into a polymer as a solar absorber. The plasmonic nature of silver nanoparticle allows for adjustments to be made in its UV-VIS-NIR absorbance spectrum. A combination of different sized/shaped particles could result in ideal absorption of the majority of the solar spectrum. Allotting this with the stability of a polymer leads to potential solids or solutions that could work as a solar absorber. Tests were also performed to determine whether or not UV-C irradiation during synthesis effects the characteristics of silver nanoparticles, in particular the absorbance. Successful synthesis of silver nanoparticle …

Synthesis, Characterization And Biological Studies Of Technetium-99m And Rhenium-188 Peptides, Vanessa Anne Sanders

UNLV Theses, Dissertations, Professional Papers, and Capstones

Radiopharmaceuticals are very powerful diagnostic tools for evaluation of a host of medical conditions. These drugs are labeled with radioactive isotopes, which are utilized to create pictures of areas of interest through absorption of the drug. They are currently in high demand due to their ability to image areas that traditional imaging devices cannot. The radioisotope 99mTc, with a half-life of 6.01 hours and a 140 keV gamma emission, is central to many radiopharmaceutical compounds. This isotope is easily obtained from a 99Mo-99mTc generator, through beta decay and column chromatography separations. Very little technetium, less than 6 ng, is needed …

2017 Petersheim Academic Exposition Schedule Of Events, Seton Hall University

Petersheim Academic Exposition

2017 Petersheim Academic Exposition

Synthesis, Characterization, And Properties Of Graphene-Based Hybrids With Cobalt Oxides For Electrochemical Energy Storage And Electrocatalytic Glucose Sensing, Sara C. Botero Carrizosa

Masters Theses & Specialist Projects

A library of graphene-based hybrid materials was synthesized as novel hybrid electrochemical electrodes for electrochemical energy conversion and storage devices and electrocatalytical sensing namely enzymeless glucose sensing. The materials used were supercapacitive graphene-family nanomaterials (multilayer graphene-MLG; graphene oxide-GO, chemically reduced GO-rGO and electrochemical reduced GOErGO) and pseudocapacitive nanostructured transition metal oxides including cobalt oxide polymorphs (CoO and Co3O4) and cobalt nanoparticles (CoNP). These were combined through physisorption, electrodeposition, and hydrothermal syntheses approaches. This project was carried out to enhance electrochemical performance and to develop electrocatalytic platforms by tailoring structural properties and desired interfaces. Particularly, electrodeposition and hydrothermal synthesis facilitate chemically-bridged …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Antitumor Activity Of Selected Derivatives Of Pyrazole- Benzenesulfonamides From Dilithiated C(Α), N-Phenylhydrazones And Lithiated Methyl 2-(Aminosulfonyl)Benzoate, N. Dwight Camper [Deceased], James M. Gum, Darby E. Lyles, William T. Pennington, Charles F. Beam, Clyde R. Metz

Journal of the South Carolina Academy of Science

Several pyrazole-benzenesulfonamides were subjected to biological evaluation involving tumor formation on potato discs caused by Agrobacterium tumefaciens. This assay led to some excellent and promising initial results with three of the pyrazole compounds showing increased tumor inhibition when compared to a recognized standard, camptothecin. The select pyrazole-benzenesulfonamides were prepared by condensation-cyclization of several dilithiated C(α),N-phenylhydrazones with lithiated methyl 2-aminosulfonyl-benzoate.

Collective Quadrupole Behavior In 106Pd, Francisco M. Prados-Estévez, Erin E. Peters, A. Chakraborty, M. G. Mynk, D. Bandyopadhyay, N. Boukharouba, S. N. Choudry, Benjamin P. Crider, P. E. Garrett, S. F. Hicks, A. Kumar, S. R. Lesher, C. J. Mckay, Marcus T. Mcellistrem, Sharmistha Mukhopadhyay, J. N. Orce, M. Scheck, J. R. Vanhoy, J. L. Wood, Steven W. Yates

Chemistry Faculty Publications

Excited states in ¹⁰⁶Pd were studied with the (n,n′γ) reaction, and comprehensive information for excitations with spin ≤6ℏ was obtained. The data include level lifetimes in the femtosecond regime, spins and parities, transition multipolarities, and multipole mixing ratios, which allow the determination of reduced transition probabilities. The E2 decay strength to the low-lying states is mapped up to ≈2.4 MeV in excitation energy. The structures associated with quadrupole collectivity are elucidated and organized into bands.

Glass Polymorphism In Glycerol–Water Mixtures: I. A Computer Simulation Study, David A. Jahn, Jessina Wong, Johannes Bachler, Thomas Loerting, Nicolas Giovambattista

Publications and Research

We perform out-of-equilibrium molecular dynamics (MD) simulations of water–glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA–HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/ decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration wg = 0–13% and find that, for the …

Mass-Analyzed Threshold Ionization Spectroscopy Of Lanthanum-Hydrocarbon Radicals Formed By C—H Bond Activation Of Propene, Sudesh Kumari, Wenjin Cao, Dilrukshi C. Hewage, Ruchira Silva, Dong-Sheng Yang

Chemistry Faculty Publications

La(C₃H₄) and La(C₃H₆) are observed from the reaction of laser-vaporized La atoms with propene by photoionization time-of-flight mass spectrometry and characterized by mass-analyzed threshold ionization spectroscopy. Two isomers of La(C₃H₄) are identified as methyl-lanthanacyclopropene [La(CHCCH₃)] (C_s) and lanthanacyclobutene [La(CHCHCH₂)] (C₁); La(C₃H₆) is determined to be H—La(η³-allyl) (C_s), a C—H bond inserted species. All three metal-hydrocarbon radicals prefer a doublet ground state with a La 6s-based electron configuration. Ionization of the neutral doublet …

Ozone Depletion, A Big Threat To Climate Change: What Can Be Done?, Sumera Aziz Ali, Savera Aziz Ali, Nadir Suhail

Community Health Sciences

Ozone in the stratosphere is very important as it acts as a safeguard for the earth and protects life from harmful ultraviolet radiations coming from the sun. Depletion of stratospheric ozone, resulting from atmospheric pollution has led to increased ultraviolet radiation at the earth’s surface as well as spectral shifts to the more biologically damaging shorter wavelengths. A decrease in the concentration of stratospheric ozone enhances the solar ultraviolet (UV) radiation, which is harmful to the growth of the plant and various other metabolic processes of the organisms and might cause changes in pigment concentrations, nucleic acids, and proteins. Multiple …

Inelastic Neutron Scattering Cross Section Measurements For 134,136Xe Of Relevance To Neutrinoless Double-Β Decay Searches, Erin E. Peters, T. J. Ross, S. H. Liu, Marcus T. Mcellistrem, Steven W. Yates

Chemistry Faculty Publications

Neutrinoless double-β decay (0νββ) searches typically involve large-scale experiments for which backgrounds can be complex. One possible source of background near the 0νββ signature in the observed spectra is γ rays arising from inelastic neutron scattering from the materials composing or surrounding the detector. In relation to searches for the 0νββ of ¹³⁶Xe to ¹³⁶Ba, such as the EXO-200 and KamLAND-Zen projects, inelastic neutron scattering γ-ray production cross sections for ¹³⁶Xe and ¹³⁴Xe are of importance for characterizing such γ rays that may inhibit the unambiguous identification of this yet-to-be-observed …

The Statistical Mechanics Of Solar Wind Hydroxylation At The Moon, Within Lunar Magnetic Anomalies, And At Phobos, W. M. Farrell, D. M. Hurley, Vincent J. Esposito, J. L. Mclain, M. I. Zimmerman

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

We present a new formalism to describe the outgassing of hydrogen initially implanted by the solar wind protons into exposed soils on airless bodies. The formalism applies a statistical mechanics approach similar to that applied recently to molecular adsorption onto activated surfaces. The key element enabling this formalism is the recognition that the interatomic potential between the implanted H and regolith-residing oxides is not of singular value but possess a distribution of trapped energy values at a given temperature, F(U,T). All subsequent derivations of the outward diffusion and H retention rely on the specific properties of this distribution. We …

Geometry-Driven Folding Of A Floating Annular Sheet, Joseph Paulsen, Vincent Démery, K. Buğra Toga, Zhanlong Qiu, Thomas P. Russell, Benny Davidovitch, Narayanan Menon

Physics - All Scholarship

Predicting the large-amplitude deformations of thin elastic sheets is difficult due to the complications of self contact, geometric nonlinearities, and a multitude of low-lying energy states. We study a simple twodimensional setting where an annular polymer sheet floating on an air-water interface is subjected to different tensions on the inner and outer rims. The sheet folds and wrinkles into many distinct morphologies that break axisymmetry. These states can be understood within a recent geometric approach for determining the gross shape of extremely bendable yet inextensible sheets by extremizing an appropriate area functional. Our analysis explains the remarkable feature that the …

Monitoring A Simple Hydrolysis Process In An Organic Solid By Observing Methyl Group Rotation, Peter A. Beckmann, Joseph M. Bohen, Jamie Ford, William P. Malachowski, Clelia W. Mallory, Frank B. Mallory, Andrew R. Mcghie, Arnold L. Rheingold, Gilbert J. Sloan, Steven T. Szewczyk, Xianlong Wang, Kraig A. Wheeler

Physics Faculty Research and Scholarship

We report a variety of experiments and calculations and their interpretations regarding methyl group (CH3) rotation in samples of pure 3-methylglutaric anhydride (1), pure 3-methylglutaric acid (2), and samples where the anhydride is slowly absorbing water from the air and converting to the acid [C6H8O3(1) + H2O → C6H10O4(2)]. The techniques are solid state 1H nuclear magnetic resonance (NMR) spin-lattice relaxation, single-crystal X-ray diffraction, electronic structure calculations in both isolated molecules and in clusters of molecules that mimic the crystal structure, field emission scanning electron microscopy, differential scanning calorimetry, and high resolution …

P1: Using Modified Dean Flow Designs To Increase Mixing Performance, Joshua Clark

Undergraduate Research Posters 2017

We are using numerical solutions for the Navier-Stokes equations and the concentration - diffusion equation to model fluid flow and reactant distribution in serpentine type channels for micromixers/microreactors development. These mixers exploit centripetal forces on the fluid to induce cross-sectional fluid mixing, aka Dean flows. Various modifications are used to increase the mixing character of these crosssectional flows. We found that the performance of these mixers exceeds that of unmodified channels and we currently assess their performance relative to other state of the art methodologies used to induce mixing on the microscale.

P2: Implementation Of Groove Based Designs For Engineering Fluid Flow In Micromixers, Tahir Butt

Undergraduate Research Posters 2017

Mixing on microscale is important for the development of miniaturized chemical reactors that use small quantities of reactants and allow better control over the reaction conditions and products. Nevertheless, achieving rapid mixing in this type of micro-reactors is challenging due to the lack of turbulence and slow diffusion on the microscale. In this work we implement micromixers designs based on surface groove/ridge patterns targeted at inducing cross-sectional flows that both extend the interface between the different reactants, as well as induce chaotic advection. We discuss the fabrication of these structures using soft-lithography in PDMS employing a mold and their optical …

Attosecond Spectroscopy Probing Electron Correlation Dynamics, Alexander Heinecke Winney

Wayne State University Dissertations

Electrons are the driving force behind every chemical reaction. The exchange, ionization, or even relaxation of electrons is behind every bond broken or formed. According to the Bohr model of the atom, it takes an electron 150 as to orbit a proton[6]. With this as a unit time scale for an electron, it is clear that a pulse duration of several femtoseconds will not be sufficient to understanding electron dynamics. Our work demonstrates both technical and scientific achievements that push the boundaries of attosecond dynamics. TDSE studies show that amplification the yield of high harmonic generation (HHG) may be possible …

Theoretical And Experimental Analysis Of Optical Properties Of Defects In Gan:, Ibrahima Castillo Diallo

Theses and Dissertations

Using the Heyd-Scuseria-Ernzherof (HSE06) hybrid functional method along with photoluminescence experimental measurements, we analyze the properties of intrinsic defects such as vacancies, interstitials, antisites, and common complexes. By using configurational coordinate diagrams, we estimate the likelihood of defects to be radiative or non-radiative. Our calculations show that gallium vacancies exhibit a large magnetic moment in the neutral charge state and are most likely non-radiative. We also investigate the correlation between the observed infrared PL bands created in 2.5 MeV electron-irradiated GaN samples and the formation of native defects. It is found that gallium-nitrogen divacancies are possible sources of the broad …