Chemistry Commons^™

Cytotoxic And Antimicrobial Effects Of Silver-Containing Surfaces, Sarah Goderecci

Theses and Dissertations

This study examines applications of sputtered silver coatings as alternatives to traditional antibiotic treatments. Given the increase in reports of antibiotic-resistant bacteria, new treatments and coatings for in-dwelling medical devices such as catheters and orthopedic implants are necessary. Silver oxide films were deposited onto Ti surfaces to examine the efficacy of such coatings against a variety of bacterial species both in vitro and in vivo. Bacterial growth studies showed that coatings exhibited antimicrobial activity against a range of bacterial species acting either in a bacteriostatic or bactericidal mechanism, depending on the target. Limited toxicity to in vitro mammalian cells was …

Utilizing Phluorin-Tagged Receptors To Monitor Subcellular Localization And Trafficking, Ashley M. Fox-Loe, Brandon J. Henderson, Christopher I. Richards

Chemistry Faculty Publications

Understanding membrane protein trafficking, assembly, and expression requires an approach that differentiates between those residing in intracellular organelles and those localized on the plasma membrane. Traditional fluorescence-based measurements lack the capability to distinguish membrane proteins residing in different organelles. Cutting edge methodologies transcend traditional methods by coupling pH-sensitive fluorophores with total internal reflection fluorescence microscopy (TIRFM). TIRF illumination excites the sample up to approximately 150 nm from the glass-sample interface, thus decreasing background, increasing the signal to noise ratio, and enhancing resolution. The excitation volume in TIRFM encompasses the plasma membrane and nearby organelles such as the peripheral ER. Superecliptic …

Poly(Ethyl Glyoxylate)-Poly(Ethylene Oxide) Nanoparticles: Stimuli- Responsive Drug Release Via End-To-End Polyglyoxylate Depolymerization, Bo Fan, Elizabeth Gillies

Chemistry Publications

The ability to disrupt polymer assemblies in response to specifi c stimuli provides the potential to release drugs selectively at certain sites or conditions in vivo. However, most stimuli-responsive delivery systems require many stimuli initiated events to release drugs. “ Self-immolative polymers” offer the potential to provide amplifi ed responses to stimuli as they undergo complete end-to-end depolymerization following the cleavage of a single end-cap. Herein, linker end-caps were developed to conjugate self-immolative poly(ethyl glyoxylate) (PEtG) with poly(ethylene oxide) (PEO) to form amphiphilic block copolymers. These copolymers were self-assembled to form nanoparticles in aqueous solution. Cleavage of the linker …

Analysis And Control Of Chain Mobility In Protein Hydrogels, Peter B. Rapp, Ahmad K. Omar, Jeff J. Shen, Maren E. Buck, Zhen Gang Wang, David A. Tirrell

Chemistry: Faculty Publications

Coiled-coil domains can direct the assembly of protein block copolymers into physically cross-linked, viscoelastic hydrogels. Here, we describe the use of fluorescence recovery after photobleaching (FRAP) to probe chain mobility in reversible hydrogels assembled from engineered proteins bearing terminal coiled-coil domains. We show that chain mobility can be related to the underlying dynamics of the coiled-coil domains by application of a three-state “hopping” model of chain migration. We further show that genetic programming allows the effective mobility of network chains to be varied 500-fold through modest changes in protein sequence. Destabilization of the coiled-coil domains by site-directed mutagenesis increases the …

Eco-Friendly (Green) Synthesis Of Magnetically Active Gold Nanoclusters, Naveen Reddy Kadasala, Lu Lin, Christopher Gilpin, Alexander Wei

Department of Chemistry Faculty Publications

Au–FexOy composite nanoparticles (NPs) are of great technological interest due to their combined optical and magnetic properties. However, typical syntheses are neither simple nor ecologically friendly, creating a challenging situation for process scale-up. Here we describe conditions for preparing Au–FexOy NPs in aqueous solutions and at ambient temperatures, without resorting to solvents or amphiphilic surfactants with poor sustainability profiles. These magnetic gold nanoclusters (MGNCs) are prepared in practical yields with average sizes slightly below 100 nm, and surface plasmon resonances that extend to near-infrared wavelengths, and sufficient magnetic moment (up to 6 emu g–1) to permit collection within minutes by …

Ice Cloud Formation Potential By Free Tropospheric Particles From Long-Range Transport Over The Northern Atlantic Ocean, Swarup China, Peter A. Alpert, B. Zhang, Simeon Schum, Katja Dzepina, Kendra Wright, R. Chris Owen, Paulo Fialho, Lynn Mazzoleni, Claudio Mazzoleni, Daniel A. Knopf

Department of Chemistry Publications

Long-range transported free tropospheric particles can play a significant role on heterogeneous ice nucleation. Using optical and electron microscopy we examine the physicochemical characteristics of ice nucleating particles (INPs). Particles were collected on substrates from the free troposphere at the remote Pico Mountain Observatory in the Azores Islands, after long-range transport and aging over the Atlantic Ocean. We investigate four specific events to study the ice formation potential by the collected particles with different ages and transport patterns. We use single-particle analysis, as well as bulk analysis to characterize particle populations. Both analyses show substantial differences in particle composition between …

Does Plasticizer Penetrate Tightly Bound Polymer In Adsorbed Poly(Vinyl Acetate) On Silica?, Boonta Hetayothin, Roy A. Cabaniss, Frank D. Blum

Chemistry Faculty Research & Creative Works

When only tightly bound poly (vinyl acetate) (PVAc) was adsorbed on silica, the plasticizer, di(propylene glycol) dibenzoate (DPGDB), was not effective in lowering its glass transition. To determine why the plasticizer was not effective, we probed the behavior of the deuterated plasticizer di (propylene glycol) dibenzoate (DPGDB-d10)/PVAc/silica system using deuterium (2H) solid state NMR and temperature-modulated differential scanning calorimetry (TMDSC). PVAc with 37% (w/w) of plasticizer/polymer was adsorbed on silica in adsorbed amounts of 2.60 and 0.76 mg PVAc/m2 silica. The dynamics of the plasticizer in the adsorbed PVAc was found to be more motionally heterogeneous than that observed in …

Multifunctional Porous Aramids (Aerogels), Fabrication Thereof, And Catalytic Compositions Derived Therefrom, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed

Chemistry Faculty Research & Creative Works

The present disclosure provides a series of new and improved porous polyamide aerogels derived from multifunctional aromatics that combine the high mechanical strength of aramids with the pore structure of aerogels. The polyamide aerogels have a hyperbranched structure, relatively low density, high porosity and may be derived from functionalized monomers having more aromatic groups than functional groups. The present disclosure also provides a new method for producing the porous polyamide aerogels by polymerizing an aromatic multifunctional carboxylic acid or a ferrocene multifunctional carboxylic acid with a polyfunctional aromatic isocyanate at moderate reaction conditions followed by drying with liquid CO2. Also …

New Reaction Discoveries In Gold Catalysis, Seyedmorteza Hosseyni

USF Tampa Graduate Theses and Dissertations

In this dissertation, gold catalyst was employed to catalyze intermolecular reactions. Intramolecular reactions were far more advanced than intermolecular reaction in gold catalysis. With finding suitable ligands for gold catalysts, we were able to develop several transformations to synthesize interesting building blocks in organic chemistry including: allenes, furans, spiros, oxepines, propargyl ethers and ketones. These functionalities were synthesized by the use of triazole-gold(I) catalyst. Triazole, as a ligand bond to gold, showed enhanced stability of the catalyst, which resulted in better yields. Gold(I)/(III) redox chemistry also used for cyclopropanol ring openings which resulted in synthesizing substituted ketones.

Synthesis And Catalytic Applications Of Non-Metal Doped Mesoporous Titania, Syed Z. Islam, Suraj R. Nagpure, Doo Young Kim, Stephen E. Rankin

Chemical and Materials Engineering Faculty Publications

Mesoporous titania (mp-TiO₂) has drawn tremendous attention for a diverse set of applications due to its high surface area, interfacial structure, and tunable combination of pore size, pore orientation, wall thickness, and pore connectivity. Its pore structure facilitates rapid diffusion of reactants and charge carriers to the photocatalytically active interface of TiO₂. However, because the large band gap of TiO₂ limits its ability to utilize visible light, non-metal doping has been extensively studied to tune the energy levels of TiO₂. While first-principles calculations support the efficacy of this approach, it is challenging to …

Comparison Of Halide Receptors Based On H, Halogen, Chalogen, Pnicogen, And Tetrel Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A series of halide receptors are constructed and the geometries and energetics of their binding to F-, Cl-, and Br- assessed by quantum calculations. The dicationic receptors are based on a pair of imidazolium units, connected via a benzene spacer. The imidazoliums each donate a proton to a halide in a pair of H-bonds. Replacement of the two bonding protons by Br leads to binding via a pair of halogen bonds. Likewise, chalcogen, pnicogen, and tetrel bonds occur when the protons are replaced, respectively, by Se, As, and Ge. Regardless of the binding group considered, F- is bound much more …

Formation, Characterization, And Optimization Of Antibody-Gold Nanoparticle Conjugates, Seth L. Filbrun

Theses and Dissertations

Protein modified gold nanoparticle based immunoassays are the basis of many novel detection techniques. There are many groups working on novel immunoassays but there is still much to understand about how many proteins are attached onto each nanoparticle and much to improve on immobilization methods. This thesis work is devoted to improving techniques for the quantification of protein immobilized on the gold nanoparticle and development of a novel approach to immobilize protein independent of pH.

The ability to evaluate antibody immobilization onto gold nanoparticles is critical for assessing coupling chemistry and optimizing the sensitivity of nanoparticle-enabled biosensors. Herein, we developed …

Polymer Micelle Formulation For The Proteasome Inhibitor Drug Carfilzomib: Anticancer Efficacy And Pharmacokinetic Studies In Mice, Ji Eun Park, Se-Eun Chun, Derek Alexander Reichel, Jee Sun Min, Su-Chan Lee, Songhee Han, Gongmi Ryoo, Yunseok Oh, Shin-Hyung Park, Heon-Min Ryu, Kyung Bo Kim, Ho-Young Lee, Soo Kyung Bae, Younsoo Bae, Wooin Lee

Pharmaceutical Sciences Faculty Publications

Carfilzomib (CFZ) is a peptide epoxyketone proteasome inhibitor approved for the treatment of multiple myeloma (MM). Despite the remarkable efficacy of CFZ against MM, the clinical trials in patients with solid cancers yielded rather disappointing results with minimal clinical benefits. Rapid degradation of CFZ in vivo and its poor penetration to tumor sites are considered to be major factors limiting its efficacy against solid cancers. We previously reported that polymer micelles (PMs) composed of biodegradable block copolymers poly(ethylene glycol) (PEG) and poly(caprolactone) (PCL) can improve the metabolic stability of CFZ in vitro. Here, we prepared the CFZ-loaded PM, PEG-PCL-deoxycholic …

Development Of A Novel Pd-Based Heterogeneous Catalyst For Co2 Conversion, Susanna Mirabelli

Discovery Day (formerly Post & Beyond)

As global warming caused by CO2 emission is becoming a serious issue that is threatening our life, various efforts have been attempted to mitigate the climate change by reducing the CO2 emission. The primary objective of this project is to develop a novel Pd-based heterogeneous catalyst to enhance the catalytic conversion of CO2 by H2 for the synthesis of value- added chemicals such as CO, methanol and fuels. The Pdbased solution we developed can be tuned to be either acidic or basic to adapt to different catalyst support. The solution was characterized by Ultraviolet-visible spectroscopy and the Pd adsorption was …

Mccrearamycins A-D, Geldanamycin-Derived Cyclopentenone Macrolactams From An Eastern Kentucky Abandoned Coal Mine Microbe, Xiachang Wang, Yinan Zhang, Larissa V. Ponomareva, Qingchao Qiu, Ryan M. Woodcock, Sherif I. Elshahawi, Xiabin Chen, Ziyuan Zhou, Bruce E. Hatcher, James C. Hower, Chang-Guo Zhan, Sean Parkin, Madan K. Kharel, S. Randal Voss, Khaled A. Shaaban, Jon S. Thorson

Center for Pharmaceutical Research and Innovation Faculty Publications

Four cyclopentenone‐containing ansamycin polyketides (mccrearamycins A–D), and six new geldanamycins (Gdms B–G, including new linear and mycothiol conjugates), were characterized as metabolites of Streptomyces sp. AD‐23‐14 isolated from the Rock Creek underground coal mine acid drainage site. Biomimetic chemical conversion studies using both simple synthetic models and Gdm D confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19‐hydroxy Gdm, and thereby provides a new synthetic derivatization strategy and implicates a potential unique biocatalyst in mccrearamycin cyclopentenone formation. In addition to standard Hsp90α binding and cell line cytotoxicity assays, this study also highlights the first assessment of Hsp90α …

Ten-Year Chemical Signatures Associated With Long-Range Transport Observed In The Free Troposphere Over The Central North Atlantic, B. Zhang, R. C. Owen, Judith Perlinger, D. Helmig, M. Val Martín, L. Kramer, Lynn Mazzoleni, C. Mazzoleni

Department of Chemistry Publications

Ten-year observations of trace gases at Pico Mountain Observatory (PMO), a free troposphere site in the central North Atlantic, were classified by transport patterns using the Lagrangian particle dispersion model, FLEXPART. The classification enabled identifying trace gas mixing ratios associated with background air and long- range transport of continental emissions, which were defined as chemical signatures. Comparison between the chemical signatures revealed the impacts of natural and anthropogenic sources, as well as chemical and physical processes during long transport, on air composition in the remote North Atlantic. Transport of North American anthropogenic emissions (NA-Anthro) and summertime wildfire plumes (Fire) significantly …

Could O-Aminoquinones Of Estrogen Metabolites Serve As Platforms For Redox Cycling?, Rachel Miller

UNO Student Research and Creative Activity Fair

The metabolism of estrogen can lead to the formation of two isomeric o-quinones, estrogen-2,3-quinone (E-2,3-Q) and estrogen-3,4-Q (E-3,4-Q). The more reactive E-3,4-Q is genotoxic and can damage DNA by forming apurinic sites; whereas, E-2,3-Q does not form apurinic sites. Estrogen quinones may also be involved in redox cycling to produce reactive oxygen species (ROS), which is another genotoxic pathway. What is not yet clear, is why E-3,4-Q would undergo redox cycling while the non-carcinogenic E-2,3-Q would not. Nitrogen nucleophiles react with the E-3,4-Q at the 1-position. With DNA bases as the nitrogen (sp2) nucleophile, the adducts formed are catechols. We …

Synthesis Of Small Molecule Anti-Trypanosomal Drugs, Samuel Anderson

UNO Student Research and Creative Activity Fair

Demand for novel chemotherapeutic agents that treat Human African Trypanosomaiasis (HAT) persists. A series of compounds sharing a 3,4’diphephyl ether skeleton were prepared for a structure activity relationship (SAR) study evaluating antitrypansomal drug candidates. Trypanocidal assays performed in vitro by the Swiss Tropical and Public Health Institute identified a lead with an IC50 of 1.35 μg/mL analogous to a compound previously made in our laboratory. A slight improvement in activity (10%) was observed when changing the molecular substitution pattern from 4,4’ to 3,3’; however, the result is equivocal. Furthermore, in vitro test results demonstrated the weakness of amides as side …

Session E-2: Sharing Analogies And Demonstrations To Reinforce Chemistry Concepts, Dave Devol, Angela Ahrendt

Professional Learning Day

Chemistry concepts can often be difficult for students to understand, in part due to the fact that we are discussing with students things that cannot be seen (atoms and molecules!). Analogies that relate chemistry concepts to things that students are more familiar with can be a powerful way to help them understand concepts, as can demonstrations that make concepts come to life visually. We will share a few of our favorite analogies/demos, and ask that each participant share one of their favorite analogies or demos. As we realize it would be difficult for visiting teachers to bring what they need …

Characterization Of The Mannose-6-Phosphate/Insulin-Like Growth Factor Ii Receptor Using 1-3mh, Zechariah Craig

UNO Student Research and Creative Activity Fair

The mannose-6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R), a recombinant triplet protein receptor for studies involving receptor dimerization, plays a pivotal role in mediating cellular growth. This receptor is comprised of fifteen similar units that fold into five triplet subunits. The goal of this experiment is to investigate how to make the 1-3MH protein more stable at the DNA level and generate a larger yield from DNA extractions for more effective transfections. This was accomplished by minorly changing the protocols for the DNA purification. Instead of using a standard column DNA purification kit, a crude DNA purification was done instead. This …

Docking Studies Of Isoform-Selectivity Of Phosphatidylinositol 3-Kinase (Pi3k) Inhibitors, Kaitlin Goettsch

UNO Student Research and Creative Activity Fair

Phosphatidylinositol 3-kinases (PI3Ks) and their related pathways are reputed targets for drug-based anticancer therapies. Mutations in PI3K genes, expression, and pathways are frequent among multiple cancer types. Four isoforms of PI3Ks exist: α, β, γ, & δ and studies have identified several ligands for each isoform which are capable of serving as inhibitory therapeutic compounds. However, the biochemical efficacy of these molecules varies and the isoform selectivity is not well understood. In this study, we applied in silico docking methods and free energy calculation methods to estimate the binding of reported PI3K ligands against 5 PI3K structures: PI3Kα (PBD ID: …

Session A-1: Bca Method, Focusing On Mole Ratios In Stoichiometry, Carmela Jones, Deb Scarano, Anita White

Professional Learning Day

Traditionally stoichiometry is done using dimensional analysis. Although effective, it is confusing, messy, and does not focus on mole ratios. On the other hand, the BCA method (Before-Change-After), is clear, clean, and highlights the mole ratios in a chemical reaction. Participants will collect mass data in an experiment and learn how to use a BCA table. Teachers will bring the BCA method back to their classrooms and provide an extremely useful tool for the next generation of chemistry savvy students.

Session C-1: Modeling Stem Activities Into Classroom Practice, Sowmya Anjur

Professional Learning Day

Students understand concepts better when they have had a chance to work hands on with relevant material. Examples will be presented from my classroom where difficult concepts have been modeled into simple experiments with considerable success in enhancing student understanding. Special focus will be given to selected topics that students seem to have the most difficulty grasping. The objective is to enable students to transfer their understanding to solve complex problems with considerable ease and apply their understanding to real world scenarios on assessments. Suggestions will also be provided for implementation of various concepts into the high school classroom.

Understanding The Role Of Protein Misfolding In Neurodegenerative Diseases, Ashutosh Tiwari

TechTalks

Protein aggregates are hallmark of several age related disorders including neurodegenerative diseases such as Amyotrophic Lateral Sclerosis, Alzheimer’s and Parkinson’s disease. However, the underlying mechanisms by which these aggregated proteins impair cellular functions and cause toxicity is not clear. I will discuss efforts from my laboratory to characterize these misfolded and aggregated protein structures and their associated toxicity.

Designing Proteins For Biomechanical And Molecular Biological Studies, Momoko Tajiri

TechTalks

Proteins are large biomolecules consisting one or more long chain of amino acid residues. Proteins perform a wide variety of functions within organisms including catalyzing metabolic activities, signal transduction, and transportation of molecules. They function differently from one another as their sequences of amino acids and also due to a variation of modification placed on residues. Change in modification patterns will impact protein interaction with other molecules, thus influence normal cell activities and may lead to disease development. In order to study the consequences of modification, we have a method to prepare proteins with desired modification patterns. Using the technique, …

Proton Transfer And Esterification Reactions In Emimoac-Based Acidic Ionic Liquids, Anh T. Tran, Phuoc H. Lam, Alexandra M. Miller, Dustin J. Walczyk, Jay Tomlin, Timothy D. Vaden, Lei Yu

College of Science & Mathematics Departmental Research

Acetate-based ionic liquids (such as 1-ethyl-3-methylimidazolium acetate, EMIMOAc) have potential applications for CO2 absorption and electrochemical reduction, chemical separations and extractions, and Fischer esterification of alcohols, amines, and starch. Both strong and weak organic acids can be dissolved in EMIMOAc and yield interesting proton-rich acidic ionic liquid solutions. We have used GCMS vapor pressure measurements, spectroscopic methods, calorimetry, and viscosity/conductivity measurements to investigate the properties and reactions of various acids dissolved in EMIMOAc. Unique proton transfer and esterification reactions are observed in many of these acidic solutions with carboxylic acids or sulfonic acids as solutes. Some acids react with the …

Polycyclic Aromatic Hydrocarbons With Aliphatic Sidegroups: Intensity Scaling For The C-H Stretching Modes And Astrophysical Implications, Xuejuan Yang, Aigen Li, Rainer Glaser, Jianxin Zhong

Chemistry Faculty Research & Creative Works

The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 μm ubiquitously seen in a wide variety of astrophysical regions are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules. Astronomical PAHs may have an aliphatic component, as revealed by the detection in many UIE sources of the aliphatic C-H stretching feature at 3.4 mm. The ratio of the observed intensity of the 3.4 mm feature to that of the 3.3 μm aromatic C-H feature allows one to estimate the aliphatic fraction of the UIE carriers. This requires knowledge of the intrinsic oscillator strengths of the 3.3 …

Crystal Structure Of Li3ga(Bo3)2, Robert W. Smith, Darien Holman, Eric M. Villa

Chemistry Faculty Publications

The crystal structure of trilithium gallium bis(orthoborate), Li3Ga(BO3)2, is isotypic with Li3Al(BO3)2 in a triclinic cell in space-group type P1. The three Li and the unique Ga atom are coordinated by four O atoms each in tetrahedra, and the two B atoms are coordinated by three O atoms in orthoborate triangles. Chains with composition [Ga2(BO3)4] 6 extend along the a axis. The Li atoms interleave these chains in tetrahedral interstices. A comparison is made between the structure model of the title compound and that of a previously reported model for a compound with the same composition [Abdullaev & Mamedov (1972). …

Benzene Formation In Electronic Cigarettes, James F. Pankow, Kilsun Kim, Kevin J. Mcwhirter, Wentai Luo, Jorge O. Escobedo, Robert M. Strongin, Anna K. Duell, David H. Peyton

Chemistry Faculty Publications and Presentations

The heating of the fluids used in electronic cigarettes (“e-cigarettes”) used to create “vaping” aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine.

Protection Of The Queuosine Biosynthesis Enzyme Quef From Irreversible Oxidation By A Conserved Intramolecular Disulfide, Adeba Mohammad, Adriana Bon Ramos, Bobby W.K. Lee, Spencer William Cohen, Maryam K. Kiani, Dirk Iwata-Reuyl, Boguslaw Stec, Manal A. Swairjo

Chemistry Faculty Publications and Presentations

QueF enzymes catalyze the nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of the nitrile group of 7-cyano-7-deazaguanine (preQ0) to 7-aminomethyl-7-deazaguanine (preQ1) in the biosynthetic pathway to the tRNA modified nucleoside queuosine. The QueF-catalyzed reaction includes formation of a covalent thioimide intermediate with a conserved active site cysteine that is prone to oxidation in vivo. Here, we report the crystal structure of a mutant of Bacillus subtilis QueF, which reveals an unanticipated intramolecular disulfide formed between the catalytic Cys55 and a conserved Cys99 located near the active site. This structure is more symmetric than the substrate-bound structure and exhibits major rearrangement of …