Chemistry Commons^™

Bioavailability And Transformation Of Silver Nanoparticles In The Freshwater Environment, Seth W. Brittle

Browse all Theses and Dissertations

The proliferation of silver nanoparticles (AgNPs) in consumer products and industrial applications has generated many environmental concerns since the chemistry of silver changes at the nanoscale and the very properties that make them desirable – their unique reactivity – may pose environmental risks. This dissertation addresses these concerns from three different angles. First, freshwater crayfish is demonstrated as a potential benthic indicator of Ag pollution since Ag accumulation depends on the form of Ag. The uptake and distribution of Ag (from AgNPs or Ag+) in tissue samples were measured by inductively coupled plasma optical emission spectroscopy (ICP-OES). The hepatopancreas (1.5-17.4 …

A Bond Length – Bond Valence Relationship For Carbon – Nitrogen Bonds, C. Harris, F. D. Hardcastle

Journal of the Arkansas Academy of Science

In a recent study, Pauling’s relationship between bond length and valence was derived along with a definition for his fitting parameter b that incorporates the orbital exponents for each atom contributing to the bond of interest. The values of b for various bonds, including C-N bonds, were calculated using the orbital exponent data. In this study, Pauling’s correlation between bond length and bond valence, as well as his valence sum rule, were used with the recently-derived definition for b in order to produce a relationship specifically applicable to C-N bonds. The resulting equation was checked against published x-ray diffraction data …

Properties And Drug-Likeness Of Compounds That Inhibit Ebola Virus Disease (Evd), Ronald Bartzatt

Chemistry Faculty Publications

Aims: To present the molecular structures of compounds that has been shown to inhibit the proliferation of Ebola virus. To elucidate the molecular properties of these virus inhibiting compounds.

Study Design: The molecular properties of virus inhibiting compounds are elucidated and compiled. Pattern recognition methods and statistical analysis are applied to determine optimal properties of this group of compounds.

Place and Duration of Study: Chemistry Department, Durham Science Center, University of Nebraska, Omaha NE. between December 2015 and February 2016.

Methodology: A total of 60 compounds were identified as inhibiting the virus Ebola. The molecular properties such as Log P, …

Comparison Of Π-Hole Tetrel Bonding With Σ-Hole Halogen Bonds In Complexes Of Xcn (X = F, Cl, Br, I) And Nh3, Steve Scheiner, Vincent De Paul Nziko

Chemistry and Biochemistry Faculty Publications

In addition to the standard halogen bond formed when NH₃ approaches XCN (X=F,Cl,Br,I) along its molecular axis, a perpendicular approach is also possible, toward a π-hole that is present above the X-C bond. MP2/aug-cc-pVDZ calculations indicate the latter geometry is favored for X=F, and the σ-hole structure is preferred for the heavier halogens. The π-hole structure is stabilized by charge transfer from the NH₃ lone pair into the π*(CN) antibonding orbital, and is characterized by a bond path from the N of NH₃ to the C atom of XCN, a form of tetrel bond. The most stable …

Novel Photodynamic Cancer Therapy Agent And Biochemical Phosphate Sensor Based On Nanomaterials, Alaa Fadhel

Electronic Theses and Dissertations

Biochemical research and clinical studies have revolutionized the field of medicine in both diagnosis and therapy. Researchers in the field of biochemistry and biotechnology are using nanomaterials in different applications to develop devices and materials that offer benefits to both patients and the health care industry. These include biochemical sensors, enzyme encapsulation, biomarkers, and drug delivery improvements for the treatment of cancer. This dissertation focuses on investigating two biochemical aspects using nanomaterials; namely therapy and clinical diagnosis. For therapy purposes, Silica nanoparticles were used as drug delivery system to develop a new photodynamic cancer therapy agent photo-acid generator (PAG) that …

Improving Information Literacy Through Wikipedia Editing In The Chemistry Classroom: Lessons Learned, Ye Li, Charity Flener Lovitt, Anne J. Mcneil, Kristen S. Shuyler

Libraries

Assignments in which students edit Wikipedia may help students learn about the complexities of information creation and production, while engaging them in researching and writing about topics related to class content. This chapter presents two case studies that illustrate how Wikipedia-based activities can be designed to achieve both chemistry and information literacy learning outcomes. In both examples, faculty partnered with a librarian to implement the Wikipedia editing assignments. Through these experiences, those involved learned about Wikipedia and its community, and identified promising practices for project requirements based on formal and informal assessment and observations. Reflections are offered on the value …

Zoloft, Hannah Kollross

Natural Sciences Student Research Presentations

This is a poster presented at the Natural Sciences Poster Session at Parkland College, which provides the chemical makeup, dosage, and the body's response to Sertraline Hydrochloride (Zoloft), a medication used to treat major depression, obsessive-compulsive disorder, social anxiety disorder, premenstrual dysphoric disorder, generalized anxiety, and post-traumatic stress disorder.

Photoassisted Generation Of Complex N, O, S Polyheterocycles, Weston James Umstead

Electronic Theses and Dissertations

This research set out to continue the exploration and diversification of excited state o-azaxylylene cycloadditions, utilizing both pre-photochemical and post-photochemical modifications.

Pre-photochemical modifications came through the addition of heteroatoms, namely nitrogen and oxygen, to the tether that links the unsaturated photopendant to the photogenerated o-azaxylylene. Photochemistry resulted in the formation of new, interesting N, O, S polyheterocycles.

Post-photochemical modifications took place through several different cycloaddition reactions, including a [4+2] hetero-Diels Alder reaction, a [4+2] Povarov cyclization, a [3+2] nitrile oxide addition, and a [3+2] nitrone cyclization. These reactions were applied first to a model system, and then to …

Hlarp7 C-Terminal Domain Contains An Xrrm That Binds The 3' Hairpin Of 7sk Rna, Catherine D. Eichhorn, Rahul Chug, Juli Feigon

Department of Chemistry: Faculty Publications

The 7SK small nuclear ribonucleoprotein (snRNP) sequesters and inactivates the positive transcription elongation factor b (P-TEFb), an essential eukaryotic mRNA transcription factor. The human La-related protein group 7 (hLARP7) is a constitutive component of the 7SK snRNP and localizes to the 3' terminus of the 7SK long noncoding RNA. hLARP7, and in particular its C-terminal domain (CTD), is essential for 7SK RNA stability and assembly with P-TEFb. The hLARP7 N-terminal Lamodule binds and protects the 3' end from degradation, but the structural and functional role of its CTD is unclear.We report the solution NMR structure of the hLARP7 CTD and …

Analytic Ab Initio-Based Molecular Interaction Potential For The Bro·H2O Complex, Ross D. Hoehn, Sachin D. Yeole, Sabre Kais, Joseph S. Francisco

Department of Chemistry: Faculty Publications

Radical halogen oxide species play important roles within atmospheric processes, specifically those responsible for the removal of O3. To facilitate future investigations on this family of compounds, RCCSD(T)/aug-cc-pVQZ-level electronic structure calculations were employed to generate individual-molecule optimized geometries, as well as to determine the global minimum energy structure for the BrO·H₂O complex. This information facilitated the generation of several one-dimensional potential energy surface (PES) scans for the BrO·H₂O complex. Scans were performed for both the ground state and the first excited state; this inclusion is due to a low-lying first electronic excited-state energy. These rigid-geometry PES …

Ring Closures And The Hammond Postulate, Charles A. Kingsbury

Department of Chemistry: Faculty Publications

This work reports an investigation of ring closure processes in relation to the Hammond postulate. Calculations favor the importance of thermodynamics, not kinetics, as the basis for the Hammond postulate. A kinetically rapid, but thermodynamically unfavorable reaction is shown to resemble product. The ease of ring closure to three-membered rings, compared to four-membered rings, is thought to be associated with conformational mobility and perhaps vibrations coupled to the reaction coordinate motion in the case of four-membered rings.

Agricultural Fires In The Southeastern U.S. During Seac4Rs: Emissions Of Trace Gases And Particles And Evolution Of Ozone, Reactive Nitrogen, And Organic Aerosol, Xiaoxi Liu, Y. Zhang, L. G. Huey, R. J. Yokelson, Y. Wang, J. L. Jimenez, P. Campuzano-Jost, A. J. Beyersdorf, D. R. Blake, Y. Choi, J. M. St. Clair, J. D. Crounse, D. A. Day, G. S. Diskin, A. Ried, S. R. Hall, T. F. Hanisco, L. E. King, S. Meinardi, T. Mikoviny, B. B. Palm, J. Peischl, A. E. Perring, I. B. Pollack, T. B. Ryerson, G. Sachse, J. P. Schwarz, I. J. Simpson, D. J. Tanner, K. L. Thornhil, K. Ullmann, R. J. Weber, P. O. Wennberg

Chemistry and Biochemistry Faculty Publications

Emissions from 15 agricultural fires in the southeastern U.S. were measured from the NASA DC-8 research aircraft during the summer 2013 Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign. This study reports a detailed set of emission factors (EFs) for 25 trace gases and 6 fine particle species. The chemical evolution of the primary emissions in seven plumes was examined in detail for ~1.2 h. A Lagrangian plume cross-section model was used to simulate the evolution of ozone (O3), reactive nitrogen species, and organic aerosol (OA). Observed EFs are generally consistent with previous …

Planning, Implementation, And Scientific Goals Of The Studies Of Emissions And Atmospheric Composition, Clouds And Climate Coupling By Regional Surveys (Seac4Rs) Field Mission, Owen B. Toon, Hal Maring, Jack Dibb, Richard Ferrare, Daniel J. Jacob, Eric J. Jensen, Z. Johnny Luo, Gerald G. Mace, Laura L. Pan, Lenny Pfister, Karen H. Rosenlof, Jens Redemann, Jeffrey S. Reid, Hanwant B. Singh, Anne M. Thompson, Robert Yokelson, Patrick Minnis, Gao Chen, Kenneth W. Jucks, Alex Pszenny

Chemistry and Biochemistry Faculty Publications

The Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) fieldmission based at Ellington Field, Texas, during August and September 2013 employed the most comprehensive airborne payload to date to investigate atmospheric composition over North America. The NASA ER-2, DC-8, and SPEC Inc. Learjet flew 57 science flights fromthe surface to 20 km. The ER-2 employed seven remote sensing instruments as a satellite surrogate and eight in situ instruments. The DC-8 employed 23 in situ and five remote sensing instruments for radiation, chemistry, and microphysics. The Learjet used 11 instruments to explore cloud microphysics. SEAC4RS …

Ice-Nucleating Particle Emissions From Biomass Combustion And The Potential Importance Of Soot Aerosol, E. J.T. Levin, G. R. Mcmeeking, P. J. Demott, C. S. Mccluskey, C. M. Carrico, S. Nakao, T. Jayarathne, E. A. Stone, C. E. Stockwell, R. J. Yokelson, S. M. Kreidenweis

Chemistry and Biochemistry Faculty Publications

Ice-nucleating particles (INPs) are required for initial ice crystal formation in clouds at temperatures warmer than about -36°C and thus play a crucial role in cloud and precipitation formation. Biomass burning has been found to be a source of INPs in previous studies and is also a major contributor to atmospheric black carbon (BC) concentrations. This study focuses on isolating the BC contribution to the INP population associated with biomass combustion. Emissions of condensation mode INPs from a number of globally relevant biomass fuels were measured at -30°C and above water saturation as fires progressed from ignition to extinguishment in …

Rapidly Evolving Ultrafine And Fine Mode Biomass Smoke Physical Properties: Comparing Laboratory And Field Results, Christian M. Carrico, Anthony J. Prenni, Sonia M. Kreidenweis, Ezra J.T. Levin, Christina S. Mccluskey, Paul J. Demott, Gavin R. Mcmeeking, Shunsuke Nakao, Chelsea Stockwell, Robert J. Yokelson

Chemistry and Biochemistry Faculty Publications

Combining field and laboratory results, we present biomass smoke physical properties. We report sub-0.56 µm diameter (Dp) particle sizing (fast mobility particle sizer, FMPS) plus light absorption and scattering at 870nm (photoacoustic extinctiometer). For Dp<200 >nm, the FMPS characterized sizing within ±20% compared to standards. As compared to the traditional scanning mobility particle sizer, the FMPS responded most accurately to single-mode polydispersions with mean Dp<200 >nm, which characterized the smoke sampled here. Smoke was measured from laboratory fresh emissions (seconds to hours old), the High Park Fire (hours to<1 >day), and from regional biomass burning (several days). During a High …

Sign Learning Kink-Based (Silk) Quantum Monte Carlo For Molecular Systems, Xiaoyao Ma, Randall W. Hall, Frank Loffler, Karol Kowalski, Kiran Bhaskaran-Nair, Mark Jarrell, Juana Moreno

Collected Faculty Scholarship

The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initioground state energies for multiple geometries of the H₂O, N₂, and F₂ molecules. The method is based on Feynman’s path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of …

The Periodical Winter 2016, Southern Adventist University

the Periodical – Chemistry Department Newsletter

Volume 3, issue 2 of the Periodical includes articles about the Chemistry Club's community service, a pictorial listing of May 2016 graduates, student Jeron Estwick's presentation at a chemistry conference, a feature on students recognized for academic achievement, and an alumni spotlight.

Exact Expressions For The Kohn–Sham Exchange-Correlation Potential In Terms Of Wave-Function-Based Quantities, Rogelio Cuevas-Saavedra, Viktor N. Staroverov

Chemistry Publications

Several workers have deduced various exact expressions for the Kohn–Sham exchange-correlation potential in terms of quantities computable from the interacting and noninteracting wave functions of the system. We show that all these expressions can be obtained by one general method in which the interacting N-electron wave function is expanded in products of one- and (N − 1)-electron functions. Different expressions correspond to different choices of the latter functions. Our analysis unifies and clarifies the previously proposed exact treatments of the exchange-correlation potential, and suggests new ways of expressing this quantity.

Controlled Positioning Of Analytes And Cells On A Plasmonic Platform For Glycan Sensing Using Surface Enhanced Raman Spectroscopy, Mohammadali Tabatabaei, Gregory Q Wallace, Fabiana A Caetano, Elizabeth R Gillies, Stephen S G Ferguson, François Lagugné-Labarthet

Chemistry Publications

The rise of molecular plasmonics and its application to ultrasensitive spectroscopic measurements has been enabled by the rational design and fabrication of a variety of metallic nanostructures. Advanced nano and microfabrication methods are key to the development of such structures, allowing one to tailor optical fields at the sub-wavelength scale, thereby optimizing excitation conditions for ultrasensitive detection. In this work, the control of both analyte and cell positioning on a plasmonic platform is enabled using nanofabrication methods involving patterning of fluorocarbon (FC) polymer (C

Pincer-Plus-One Ligands In Self-Assembly With Palladium(Ii): A Molecular Square And A Molecular Tetrahedron, Ava Behnia, Paul D. Boyle, Mahmood A. Fard, Johanna M. Blacquiere, Richard J. Puddephatt

Chemistry Publications

The combination of a palladium(ii) precursor with a diimine-phenol ligand and an oxidant (H2O2 or O2) under different conditions has, serendipitously, given both a molecular square and a molecular tetrahedron by self-assembly of building blocks comprising palladium(ii) centres coordinated to the oxidised forms of the ligand.

Catalytic Cyclization And Competitive Deactivation With Ru(PR2nR′2) Complexes, J. M. Stubbs, J. P.J. Bow, R. J. Hazlehurst, J. M. Blacquiere

Chemistry Publications

The first successful use of the PR2NR′2 (1,5-R′-3,7-R-1,5-diaza-3,7-diphosphacyclooctane) ligand family toward an organic synthesis is described. The precatalysts [Ru(Cp)(PR2NBn2)(MeCN)]PF6 are active toward cyclization of 2-ethynylbenzyl alcohol at low catalyst loading and mild temperatures. Catalyst performance however is limited by both low conscription and by competitive deactivation.

Modified Electrodes With Grafted Dna And Oligonucleotides For Detection And Quantification Of Peroxynitrate, Heba Azmy Salim

ETD Archive

Peroxynitrite (ONOO-) is a strong oxidizing and nitrating agent, and its formation has been correlated with many pathological conditions. It is generated in-vivo through the diffusion-controlled reaction between nitric oxide and superoxide. Peroxynitrite has been linked to nitration of protein and DNA as well as to DNA strand breaks. Accumulation of mutations and/or other kinds of DNA damage represent a carcinogenic risk. The accurate measurement of peroxynitrite concentration has been a challenge since this analyte is very unstable and reacts with many cellular targets. Development of analytical techniques capable of rapid and sensitive detection of this fast-reacting and damaging agent …

Profiling Cell Surface Sialylation And Desialylation Dynamics Of Immune Cells, Dan Wang

ETD Archive

Sialic acids (SAs) are a diverse family of naturally occurring 2-keto-3-deoxy-nononic acids that are involved in a wide range of biological processes, including early fetal development, cellular recognition, and utilization by microbes. While it is clear that cell surface SAs are highly involved in the immune system, the sialylation status of individual immune cells and functions are still unknown. In this study, I combined the newly developed LC-MS/MS methods with flow cytometry and confocal microscopy to systematically study the sialylation and desialylation dynamics of macrophages at different conditions.

First, I developed an accurate LC-MS/MS method to quantify free SA in …

The Role Of Rnase L In Type I Diabetes And Development Of Quantitative Lc-Ms/Ms Methods For The Pharmacological Studies Of Anti-Cancer Drug Candidates, Chun Zeng

ETD Archive

PROJECT I: The cause of type I diabetes continues to be a focus of investigation. In this study, we found that 2-5A dependent RNase L (RNase L), an IFN-a-inducible enzyme that functions in IFN action against viruses and cell proliferation, played an important role in dsRNA-induced onset of type I diabetes. By using RNase L deficient RIP-B7.1 mice which are more vulnerable to environmental harmful factors such as viral infection, we demonstrated that deficiency of RNase L in mice resulted in a significant delay of diabetes onset induced by polyinosinic:polycytidylic acid (poly I:C), a type of dsRNA, and streptozotocin (STZ). …

Eradicating Mass Spectrometric Glycan Rearrangement By Utilizing Free Radicals, Nikunj Desai, Daniel A. Thomas, Jungeun Lee, Jinshan Gao, Jesse L. Beauchamp

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

Mass spectrometric glycan rearrangement is problematic because it provides misleading structural information. Here we report on a new reagent, a methylated free radical activated glycan sequencing reagent (Me-FRAGS), which combines a free radical precursor with a methylated pyridine moiety that can be coupled to the reducing terminus of glycans. The collisional activation of Me-FRAGS-derivatized glycans generates a nascent free radical that concurrently induces abundant glycosidic bond and cross-ring cleavage without the need for subsequent activation. The product ions resulting from glycan rearrangement, including internal residue loss and multiple external residue losses, are precluded. Glycan structures can be easily assembled and …

New Approaches To Chalcogenide Materials For Thermoelectrics: Lead Telluride-Based Nanostructures And Facile Synthesis Of Tetrahedrite And Doped Derivatives, Derak Justin James

Wayne State University Dissertations

The overall purpose of this work is to address several of the roadblocks to use of thermoelectric materials for generation of electricity, namely inefficient processing of materials and low performance, commonly rated by the figure of merit, ZT=T2/tot. The ZT includes  as the Seebeck coefficient,  as electrical resistivity, T as the average temperature, and tot as total thermal conductivity. tot is the sum of electronic charge carrier (C) and lattice (L) contributions to thermal conductivity. Attempts to increase ZT in the literature to values >1 have focused on decreasing the thermal conductivity via nanostructuring or optimizing the electrical …

Use Of 17o-Nmr Spectroscopy To Study The Coordination Chemistry Of Trivalent Lanthanide Ions In Solution, Zhijin Lin

Wayne State University Dissertations

Trivalent lanthanide (Ln3+)-containing complexes have a number of important applications in molecular imaging, catalysis, medical diagnosis, information storage, and environmental sensing. The properties of Ln3+-containing complexes that are useful for these applications are influenced by coordination chemistry, including the number of coordinated ligands and ligand-exchange rates. The coordination numbers for water molecules bound to Eu3+ and Tb3+ have been studied by luminescence-decay measurements; however, the coordination numbers of other important oxygen-containing functional groups such as ketones, esters, ethers, sulfonyls, amides, phosphine oxides, and aldehydes have not been as thoroughly studied in solution because of the lack of hydroxyl groups that …

Studying The Atp Cosubstrate Promiscuity Of Nucleotide And Lipid Kinases, Thilani Murium Anthony

Wayne State University Dissertations

The kinase family consist of a large assortment of enzymes that phosphorylate a variety of substrates, including proteins, nucleosides, polynucleotides, lipids, sugars, and other small molecules. The Pflum lab recently found that protein kinases promiscuously accept an ATP analog containing a biotin at the γ-phosphate (ATP-biotin) as a cosubstrate to label the hydroxyl side chains of Ser, Thr and Tyr residues with biotin. The main goal of this new project is to extend the use of kinase-catalyzed biotinylation towards polynucleotides. Crystallographic studies of T4 polynucleotide kinase (T4 PNK) that phosphorylates the 5’-hydroxyl termini of DNA and RNA show a solvent …

Design Of First-Row Transition Metal Bis(Alkoxide) Complexes And Their Reactivity Toward Nitrene And Carbene Transfer, James Bellow

Wayne State University Dissertations

The novel alkoxide ligand [OCtBu2Ph], or [OR], was synthesized in a single step as a lithium salt. It was then reacted with a series of first-row transition metal(II) halides, with widely varying results. Upon reaction with chromium, manganese, iron, or cobalt(II) chloride, dimeric complexes of the form M2(OR)4Li2Cl2 were formed, which displayed rare seesaw geometry at the metal. This unusual geometry was confirmed by various spectroscopic and computational studies. Computational studies also indicate that the steric bulk of the ligand, as well as the inclusion of lithium atoms in the molecules, are what lead to the seesaw geometry. Reaction of …

State Resolved Sliced Imaging Of Infrared Multiphoton Dissociation, Ravin Lakshitha Fernando

Wayne State University Dissertations

This dissertation focuses on unimolecular dissociations of molecules under colissionless conditions with IRMPD. IRMPD was used as the dissociation technique in these studies since roaming type dissociations predominates from the ground electronic state. DC slice imaging was used with REMPI as the detection technique to study the products in a state selective manner to understand the nano scale dynamics of unimolecular dissociations. In the investigation of photodissociation dynamics of nitromethane and methyl nitrite with IRMPD, nitromethane show very low translational energy release of the photofragments and resemble the “roaming” pathway in the dissociation of nitromethane. The difference in the intensities …