Digital Commons Network^™

Measurement Of Hono, Hnco, And Other Inorganic Acids By Negative-Ion Proton-Transfer Chemical-Ionization Mass Spectrometry (Ni-Pt-Cims): Application To Biomass Burning Emissions, J. M. Roberts, P. Veres, C. Warneke, J. A. Neuman, R. A. Washenfelder, S. S. Brown, M. Baasandorj, J. B. Burkholder, I. R. Burling, T. J. Johnson, Robert J. Yokelson, J. De Gouw

Chemistry and Biochemistry Faculty Publications

A negative-ion proton-transfer chemical ionization mass spectrometric technique (NI-PT-CIMS), using acetate as the reagent ion, was applied to the measurement of volatile inorganic acids of atmospheric interest: hydrochloric (HCl), nitrous (HONO), nitric (HNO(3)), and isocyanic (HNCO) acids. Gas phase calibrations through the sampling inlet showed the method to be intrinsically sensitive (6-16 cts/pptv), but prone to inlet effects for HNO(3) and HCl. The ion chemistry was found to be insensitive to water vapor concentrations, in agreement with previous studies of carboxylic acids. The inlet equilibration times for HNCO and HONO were 2 to 4s, allowing for measurement in biomass burning …

2,4,6-Triphenyl­Aniline, Onome Ugono, Stephanie Cowin, Alicia Beatty

Chemistry & Biochemistry Faculty Works

Individual mol­ecules of the title compound, C24H19N, do not participate in hydrogen-bonding inter­actions due to the steric bulk of the phenyl rings ortho to the amine. The dihedral angles between the central ring and the pendant rings are 68.26 (10), 55.28 (10) and 30.61 (11)°.

Synthesis, Functionalization And Characterization Of Dual Mode Nanoparticles For Biomedical Applications, Farah Radwan

Theses and Dissertations

Three different approaches were used to prepare dual mode nanoparticles using a previously described reverse micelle technique. Superparamagnetic Fe@FeOx core shell nanoparticles were chosen to be the magnetic component for all three dual mode systems. In the first type of particles, 2- amino-1,3- propane diol (APD) was used as a functionalization ligand to stabilize the surface of the particles and its functional amino group also provided a binding site for the attachment of a fluorescent probe. The TEM analysis showed that the APD coated particles have a size range of 8-13 nm while XPS and MALDI measurements confirmed the presence …

The Nature Of The O-2/O-5 Cooperative Effect And Its Role In Chemical Glycosylation, Laurel Kathryn Mydock

Dissertations

Since carbohydrates were first discovered, understanding the structure, reactivity, and function of these bioorganic compounds has remained of great priority. However, as the appreciation for the biological roles of carbohydrates intensifies, a growing demand for efficient and scalable methods towards the synthesis of these challenging molecules has become even more imperative. While modern synthetic techniques have allowed us to readily achieve most glycosidic linkages, it is the inability to effectively predict and control the stereoselectivity of the glycosylation reaction that has remained the synthetic hurdle. Herein, much effort has been placed in the investigation of “mixed-patterned” glycosyl donors as they …

Core-Shell Nanoparticles: Synthesis, Design, And Characterization, Kyler Carroll

Theses and Dissertations

The design of core/shell nanoparticles is of great interest for a wide range of applications. The primary focus of this dissertation is on the design and optimization of two synthetic routes. The first one is an aqueous reduction method using sodium borohydride and sodium citrate. This method was extended to design two types of core/shell nanoparticles, both of which have many applications in bio-sensing, magnetic resonance imaging, and magnetically guided SERS for the identification of environmental threats. The first, Fe/Ag core/shell nanoparticles were designed using a novel one-pot method by varying the AgNO₃ addition time in the system. For …

Synthesis Of Glycolipids And Evaluation Of Their Nkt Cell Stimulatory Properties, Yang Liu

Theses and Dissertations

Natural killer T (NKT) cells are a subset of T cells that modify a variety of immune responses. NKT cells recognize glycolipid antigen presented by a molecule called CD1d, a nonclassical antigen-presenting molecule. The best known subset of CD1d-dependent NKT cells expresses an invariant T cell receptor Vα (TCR-α) chain. These are referred to as type I or invariant NKT (iNKT) cells. When stimulated by a glycolipid, NKT cells rapidly release large amounts of cytokines. Cytokines released by NKT cells can induce either Th1 or Th2 responses. Th1 cytokines are effective in regulating bacterial, parasitic, and viral infections. But Th1 …

Rhodium-Catalyzed Hydroboration: Directed Asymmetric Desymmetrization, Judy L. Miska

Department of Chemistry: Dissertations, Theses, and Student Research

Rhodium-catalyzed asymmetric hydroboration in conjunction with directing groups can be used control relative and absolute stereochemistry. Hydroboration has the potential to create new C–C, C–O, and C–N bonds from an intermediate C–B bond with retention of stereochemistry. Desymmetrization resulting in the loss of one or more symmetry elements can give rise to molecular chirality, i.e., the conversion of a prochiral molecule to one that is chiral. Unsaturated amides and esters hold the potential for two-point binding to the rhodium catalyst and have been shown to direct the regiochemistry and impact stereochemistry in asymmetric hydroborations of acyclic β,γ-unsaturated substrates. In …

Effects Of Hydrogen Bonding On Vibrational Normal Modes Of Pyrimidine, Austin A. Howard, Gregory S. Tschumper, Nathan I. Hammer

Chemistry Faculty Research & Creative Works

The effects of weak intermolecular interactions on 10 vibrational normal modes of pyrimidine are investigated by Raman spectroscopy and electronic structure computations. Hydrogen-bonded networks of water induce a shift to higher energy in certain normal modes of pyrimidine with increasing water concentration, while other modes are relatively unaffected. Pyrimidine molecules also exhibit weak C-H⋯N interactions and shifted normal modes upon crystallization. The selective nature of the shifting of normal modes to higher energy allows for definitive assignments of the nearly degenerate ν8a and ν8b modes with polarized Raman spectroscopy. Natural bond orbital (NBO) analyses indicate that when water molecules donate …

Short-Chain Carboxylic Acids From Gray Catbird (Dumetella Carolinensis) Uropygial Secretions Vary With Testosterone Levels And Photoperiod, Rebecca J. Whelan, Tera C. Levin, Mary C. Garvin

Faculty & Staff Scholarship

The uropygial gland of birds produces secretions that are important in maintaining the health and structural integrity of feathers. Non-volatile components of uropygial secretions are believed to serve a number of functions including waterproofing and conditioning the feathers. Volatile components have been characterized in fewer species, but are particularly interesting because of their potential importance in olfactory interactions within and across species. We used solid-phase microextraction headspace sampling with gas chromatography-mass spectrometry to detect and identify volatiles in uropygial secretions of gray catbirds (Dumetella carolinensis), a North American migratory bird. We consistently detected the following carboxylic acids: acetic, …

Novel Π-Conjugated Materials Plus Their Characterizations And Applications, Xiuxian He

All Dissertations

The theme of this dissertation will focus on the syntheses and characterization of bipyridine (bipy) containing π-conjugated polymers (CPs). Specifically, poly(p-phenylene ethynylene), polyfluorene and poly(p-phenylene vinylene) derivatives have been prepared via Sonogashira coupling, Suzuki coupling and Heck coupling, respectively. Derivatives of poly(p-phenylene ethynylene), polyfluorene and poly(p-phenylene vinylene) are known to have applications in optical and electronic devices. Through this study, polymers condensed with bulky bipy-containing TAB as one of the copolymer units have shown increased solubility and diminished intrachain/interchain aggregation in solution and in film due to the effectiveness of TAB in controlling the relative orientations of individual polymer chains. …

Oxygen Isotopes As A Tracer Of Dom Processes In River-Estuary Systems, Joy Ashley Matthews

OES Theses and Dissertations

In the biogeochemical study of dissolved organic matter (DOM) in natural waters, stable isotopes are used to provide insight into both the sources of DOM and the processes affecting its alteration. Through the research presented here, oxygen isotopes are incorporated into the study of DOM through the adaptation of a pyrolysis elemental analysis isotope ratio mass spectrometer method, and sample preparation using two-stage ultrafiltration.

The application of oxygen isotopes to the study of DOM is demonstrated in two studies. First, natural abundance of δ¹⁸O in DOM is explored in the Delaware estuary. Using a two end-member mixing model, …

De Novo Synthesis Of Polyhydroxyl Aminocyclohexanes, Anobick Sar, Sergey V. Lindeman, William A. Donaldson

Chemistry Faculty Research and Publications

The syntheses of 12 stereochemically diverse polyhydroxyl aminocyclohexane (“aminocyclitols”) derivatives are described. These short syntheses require 2–5 steps from N-(2,4-cyclohexadien-1-yl)phthalimide, which is prepared in two steps from tricarbonyl(cyclohexadienyl)iron(1+). The relative stereochemistries of the aminocyclitols were assigned by ¹H NMR spectroscopy as well as X-ray diffraction analysis.

Fluorescent Chemosensors For Toxic Organophosphorus Pesticides: A Review, Sherine O. Obare, Chandrima De, Wen Guo, Tajay L. Haywood, Tova A. Samuels, Clara P. Adams, Noah O. Masika, Desmond H. Murray, Ginger A. Anderson, Keith Campbell, Kenneth Fletcher

Faculty Publications

Many organophosphorus (OP) based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S) functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O) organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of …

Mechanistic Studies On The Electrochemistry Of Proton Coupled Electron Transfer And The Influence Of Hydrogen Bonding, Timothy Alligrant

Theses and Dissertations

This research has investigated proton-coupled electron transfer (PCET) of quinone/hydroquinone and other simple organic PCET species for the purpose of furthering the knowledge of the thermodynamic and kinetic effects due to reduction and oxidation of such systems. Each of these systems were studied involving the addition of various acid/base chemistries to influence the thermodynamics and kinetics upon electron transfer. It is the expectation that the advancement of the knowledge of acid/base catalysis in electrochemistry gleaned from these studies might be applied in fuel cell research, chemical synthesis, the study of enzymes within biological systems or to simply advance the knowledge …

Rapid Multi-Class Multi-Residue Method For The Confirmation Of Chloramphenicol And Eleven Nitroimidazoles In Milk And Honey By Liquid Chromatography Tandem Mass Spectrometry, Mark Cronly, Patrice Behan, Barry Foley, Liam Regan, Sheila Martin, Michael Doyle, Edward Malone

Articles

A confirmatory method has been developed to allow for the analysis of eleven nitroimidazoles and also chloramphenicol in milk and honey samples. These compounds are classified as A6 compounds in annex IV of council regulation 2377/90 and therefore prohibited for the use in animal husbandry. Milk samples are extracted by acetonitrile with addition of NaCl, while honey samples are first dissolved in water before a similar extraction. Honey extracts undergo a hexane wash to remove impurities. Both milk and honey extracts are evaporated to dryness and reconstituted in initial mobile phase. These are then injected onto an LC-MS/MS system and …

Quantitative Structure-Property Relationships For Predicting Group Iib Metal Binding By Organic Ligands, Aliyar Mousavi

Chemistry and Chemical Biology ETDs

Mercury (Hg), cadmium (Cd), and zinc (Zn) in the environment are all of toxicological and environmental concern, and the pollution of natural waters by any of these three elements is most serious. Mercury is the most environmentally concerning of the three because of the neurotoxin species monomethylmercury produced in aquatic systems through the methylation of Hg²⁺ by aquatic microorganisms. An important chemical process in natural waters that limits the availability of mercury for methylation is the binding of Hg(II) by natural organic matter (NOM). These associations are exceptionally strong, and as NOM is ubiquitous in aquatic environments, estimating equilibrium …

A Surface Femtosecond Two-Photon Photoemission Spectrometer For Excited Electron Dynamics And Time-Dependent Photochemical Kinetics, Zefeng Ren, Chuanyao Zhou, Zhibo Ma, Chun-Lei Xhao, Xinchun Mao, Dongxu Dai, Jerry L. Larue, Russell Cooper, Alec M. Wodtke, Xueming Yang

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

A surface femtosecond two-photon photoemission (2PPE) spectrometer devoted to the study of ultrafast excited electron dynamics and photochemical kinetics on metal and metal oxide surfaces has been constructed. Low energy photoelectrons are measured using a hemispheri- cal electron energy analyzer with an imaging detector that allows us to detect the energy and the angular distributions of the photoelectrons simultaneously. A Mach-Zehnder interferom- eter was built for the time-resolved 2PPE (TR-2PPE) measurement to study ultrafast surface excited electron dynamics, which was demonstrated on the Cu(111) surface. A scheme for measuring time-dependent 2PPE (TD-2PPE) spectra has also been developed for studies of …

Targeting Complex Cyclic Peptides For Synthesis: The Celogentin And Theonellamide Families, Joshua Wayne Robinson

Theses and Dissertations

Celogentin C and theonellamide F are a class of natural products that have potential antimitotic behavior. They both contain interesting bicyclic structures with unusual linkages within a central moiety. Celogentin C's highly functionalized tryptophan moiety has two unusual linkages, a β-substituted Leu connection to the C6 of the indole structure that makes up the left-hand ring, and a τ-N connection of the imidazole to the C2 of the indole constructing the right-hand ring. This right-hand ring connection was solved via a novel oxidative coupling procedure developed in our group and the left-hand ring was initially constructed via a radical conjugated …

Interaction Of Extracellular Domain 2 Of The Human Retina-Specific Atp-Binding Cassette Transporter (Abca4) With All-Trans-Retinal., Esther E Biswas-Fiss, Deepa S Kurpad, Kinjalben Joshi, Subhasis B Biswas

Department of Medical Laboratory Sciences & Biotechnology Faculty Papers

The retina-specific ATP-binding cassette (ABC) transporter, ABCA4, is essential for transport of all-trans-retinal from the rod outer segment discs in the retina and is associated with a broad range of inherited retinal diseases, including Stargardt disease, autosomal recessive cone rod dystrophy, and fundus flavimaculatus. A unique feature of the ABCA subfamily of ABC transporters is the presence of highly conserved, long extracellular loops or domains (ECDs) with unknown function. The high degree of sequence conservation and mapped disease-associated mutations in these domains suggests an important physiological significance. Conformational analysis using CD spectroscopy of purified, recombinant ECD2 protein demonstrated that it …

Immobilization Of Polymer-Decorated Liquid Crystal Droplets On Chemically Tailored Surfaces, Michael I. Kinsinger, Maren E. Buck, Nicholas L. Abbott, David M. Lynn

Chemistry: Faculty Publications

We demonstrate that the assembly of an amphiphilic polyamine on the interfaces of micrometer-sized droplets of a thermotropic liquid crystal (LC) dispersed in aqueous solutions can be used to facilitate the immobilization of LC droplets on chemically functionalized surfaces. Polymer 1 was designed to contain both hydrophobic (alkylfunctionalized) and hydrophilic (primary and tertiary amine-functionalized) side chain functionality. The assembly of this polymer at the interfaces of aqueous dispersions of LC droplets was achieved by the spontaneous adsorption of polymer from aqueous solution. Polymer adsorption triggered transitions in the orientational ordering of the LCs, as observed by polarized light and bright-field …

Investigation Of The Sources And Sinks Of Atmospheric Methane, Christopher Lee Butenhoff

Dissertations and Theses

The work presented here represents a number of independent studies that investigated various components of the CH₄ budget, namely the sources and sinks. We used a chemical-tracer model and created unique long-term time series of atmospheric CH₄, carbon monoxide (CO), molecular hydrogen (H₂), and methylchloroform (CH₃CCl₃) measurements at marine background air to derive histories of atmospheric hydroxyl radical (OH) - the main chemical oxidant of CH₄, biomass burning - an important source of CH₄ in the tropics, and emissions of CH₄ from rice paddies - one of …

An Effective Microwave-Induced Iodine-Catalyzed Method For The Synthesis Of Quinoxalines Via Condensation Of 12-Diamines With 12-Dicarbonyl Compounds, Debasish Bandyopadhyay, Sanghamitra Mukherjee, Robert R. Rodriguez, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

A microwave-induced iodine-catalyzed simple, rapid and convenient synthesis of different types of quinoxalines via condensation of 1,2-diamines with 1,2-dicarbonyl compounds has been accomplished with an excellent yield.

Tobacco Mosaic Virus Based Thin Film Sensor For Detection Of Volatile Organic Compounds, Michael A. Bruckman, Jie Liu, Goutam Koley, Yu Li, Brian C. Benicewicz, Zhongwei Niu, Qian Wang

Faculty Publications

A thin film sensor for the detection of volatile organic compounds (VOC) was fabricated by deposition of oligo-aniline grafted tobacco mosaic virus (TMV) onto a glass substrate. The oligo-aniline motifs were conjugated onto the TMV surface by a traditional diazonium coupling reaction to tyrosine residues followed by Cu(I) catalyzed alkyne-azide cycloaddition (CuAAC) reaction. The modified TMV was easily fabricated into a thin film by directly drop coating onto a glass substrate. Upon integration of the glass substrate into a prototypical device, the virus-based thin film exhibited good sensitivity and selectivity toward ethanol and methanol vapour.

Celogentin C And Thioviridamide: Synthetic And Structural Studies, Dmitry Nikolayevich Litvinov

Theses and Dissertations

Project I Celogentin C, isolated by Kobayashi from the seeds of Celosia argentea in 2001 exhibits strong inhibitory behavior towards polymerization of tubulin – globular protein, which plays crucial role during the cell division cycle. We have attempted synthesis of the left-hand ring of celogentin C via the intramolecular alkylation and the Knoevenagel condensation strategies. Utilizing synthetic methodologies in the field of nitroacetyl chemistry, developed by Kornblum and Rajappa we have successfully prepared the intermolecular Knoevenagel condensation product – the late-stage precursor to the left-hand ring of celogentin C. Synthesis of this key intermediate subsequently led to the preparation of …

Structural Diversity In Crystal Chemistry: Rational Design Strategies Toward The Synthesis Of Functional Metal-Organic Materials, Amy J. Cairns

USF Tampa Graduate Theses and Dissertations

Metal-Organic Materials (MOMs) represent an important class of solid-state crystalline materials. Their countless attractive attributes make them uniquely suited to potentially resolve many present and future utilitarian societal challenges ranging from energy and the environment, all the way to include biology and medicine. Since the birth of coordination chemistry, the self-assembly of organic molecules with metal ions has produced a plethora of simple and complex architectures, many of which possess diverse pore and channel systems in a periodic array. In its infancy however this field was primarily fueled by burgeoning serendipitous discoveries, with no regard to a rational design approach …

An Antimicrobial Peptide Regulates Tumor-Associated Macrophage Trafficking Via The Chemokine Receptor Ccr2, A Model For Tumorigenesis, Ge Jin, Hameem I. Kawsar, Stanley A. Hirsch, Chun Zeng, Xun Jia, Zhimin Feng, Santosh K. Ghosh, Qing Yin Zheng, Aimin Zhou, Thomas M. Mcintyre, Aaron Weinberg

Chemistry Faculty Publications

Background: Tumor-associated macrophages (TAMs) constitute a significant part of infiltrating inflammatory cells that are frequently correlated with progression and poor prognosis of a variety of cancers. Tumor cell-produced human β-defensin-3 (hBD-3) has been associated with TAM trafficking in oral cancer; however, its involvement in tumor-related inflammatory processes remains largely unknown. Methodology: The relationship between hBD-3, monocyte chemoattractant protein-1 (MCP-1), TAMs, and CCR2 was examined using immunofluorescence microscopy in normal and oral carcinoma in situ biopsy specimens. The ability of hBD-3 to chemoattract host macrophages in vivo using a nude mouse model and analysis of hBD-3 on monocytic cell migration in …

Chemical Investigation Of The Antarctic Marine Invertebrates Synoicum Adareanum And Artemisina Plumosa, Jaime Heimbegner Noguez

USF Tampa Graduate Theses and Dissertations

Of the small percentage of organisms chemically investigated over the years as potential sources of natural products, much less is known about those from the marine realm. Despite the lack of attention they have received in comparison to terrestrial organisms, marine life have recently been found to represent a valuable source for novel bioactive compounds. Cold water marine habitats are home to a plethora of organisms that have the ability to produce secondary metabolites that exhibit a great deal of diversity in both their chemical structures and biological activities. The chemical investigation of these unique and relatively unstudied ecosystems is …

Electrochemical Behavior Of Kaempferide Interaction With Protein, Li-Qing Lin, Xin-Hua Lin, Jing-Hua Chen, Li-Ying Huang, Yin-Huan Liu, Guang-Wen Li

Journal of Electrochemistry

The electrochemical behavior of kaempferide at activated GCE and the interaction of kaempferide with human serum albumin(HSA) were investigated by cyclic voltammetry. A differential pulse voltammetric method has been proposed for the determination of the HSA with kaempferide. In pH 4. 5 phosphate buffer solutions (PBS) kaempferide can react with HSA to form an electrochemically non-active supermolecular complex at activated GCE,resulting in the decrease of oxidation peak (at 0. 468 V) without the change of peak potential. The decrease of the peak current is proportional to HSA concentration in the range of 0. 05 ～ 0. 25 mg/L. The limit …

Functionalization Of Fibers Using Azlactone-Containing Polymers: Layer-By-Layer Fabrication Of Reactive Thin Films On The Surfaces Of Hair And Cellulose-Based Materials, Maren E. Buck, David M. Lynn

Chemistry: Faculty Publications

We report an approach to the functionalization of fibers and fiber-based materials that is based on the deposition of reactive azlactone-functionalized polymers and the "reactive" layer-by-layer assembly of azlactone-containing thin films. We demonstrate (i) that the azlactone-functionalized polymer poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) can be used to modify the surfaces of a model protein-based fiber (horsehair) and cellulose-based materials (e.g., cotton and paper), and (ii) that fibers functionalized in this manner can be used to support the fabrication of covalently cross-linked and reactive polymer multilayers assembled using PVDMA and poly(ethyleneimine) (PEI). The growth, chemical reactivity, and uniformity of films deposited on these substrates …

Catalytic Decomposition Of Peroxynitrite And Superoxide By Nafion Films Modified With Iron And Manganese Porphyrin, Amanda Stull, Victor Sarpong

Honors Theses

Nafion films alone and modified with inert electrolytes and metalloporphyrins were tested in their effectiveness of decomposition of aqueous peroxynitrite (PN) and superoxide. Films that were modified with a cationic manganese porphyrin, which has been shown to be responsible for catalytic decomposition of superoxide ion, were found to be most effective. Peroxynitrite was generated in solution by the decomposition of 3-morpholinosydnonimime (SIN-1) that generates nitric oxide and superoxide ion, which rapidly combine to form peroxynitrite. The tyrosine analogue 4-hydroxyphenylacetic (4-HPA) was used to trap the PN in pH 7.00 PBS buffer and was its nitrated product was detected by observing …