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2015

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Articles 271 - 300 of 1428

Full-Text Articles in Chemistry

Visible Light Responsive Systems Based On Metastable-State Photoacids, Yi Liao Aug 2015

Visible Light Responsive Systems Based On Metastable-State Photoacids, Yi Liao

Chemistry and Chemical Engineering Faculty Publications

Proton transfer is one of the most fundamental processes in nature. Metastable-state photoacids can reversibly generate a large proton concentration under visible light with moderate intensity. which provides a general approach to control various proton transfer processes. Several applications of mPAHs have been demonstrated recently including control of acid-catalyzed reactions, volume-change of hydrogels, polymer conductivity, bacteria killing, odorant release, and color change of materials. They have also been utilized to control supramolecular assemblies, molecular switches, microbial fuel cells and cationic sensors. In this talk, the mechanism, structure design, and applications of metastable-state photoacids are introduced. Recent development of different types …


X-Ray Structure Of A Mammalian Stearoyl-Coa Desaturase, Yonghong Bai, Jason G. Mccoy, Elena J. Levin, Pablo Sobrado, Kanagalaghatta R. Rajashankar, Brian G. Fox, Ming Zhou Aug 2015

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

Chemistry Faculty Research & Creative Works

Stearoyl-CoA desaturase (SCD) is conserved in all eukaryotes and introduces the first double bond into saturated fatty acyl-CoAs. Because the monounsaturated products of SCD are key precursors of membrane phospholipids, cholesterol esters and triglycerides, SCD is pivotal in fatty acid metabolism. Humans have two SCD homologues (SCD1 and SCD5), while mice have four (SCD1-SCD4). SCD1-deficient mice do not become obese or diabetic when fed a high-fat diet because of improved lipid metabolic profiles and insulin sensitivity5,6. Thus, SCD1 is a pharmacological target in the treatment of obesity, diabetes and other metabolic diseases7. SCD1 is an integral …


Applications Of Green Chemistry In Asymmetric Transfer Hydrogenation And Chiral Separations, Ruoqiu Wu Aug 2015

Applications Of Green Chemistry In Asymmetric Transfer Hydrogenation And Chiral Separations, Ruoqiu Wu

Seton Hall University Dissertations and Theses (ETDs)

Green chemistry has been applied to all aspects of the life cycle of chemically related products, including design, usage, manufacturing, analysis, and disposal. In this thesis, I focus on the green chemistry applications in organic synthesis and analytical chemistry. More specifically, allylic and chiral alcohols are abundant in natural sources such as in essential oils, and widely utilized as starting materials. They are also major components in food, fragrance, biocides and the pharmaceutical compounds. In this thesis, I report the first Ru-catalysed asymmetric transfer hydrogenation (ATH) of prochiral allylic alcohols. This reaction provides chiral secondary alcohols in excellent enantioselectivities and …


Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson Aug 2015

Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson

Chemistry and Biochemistry Faculty Publications

A comprehensive suite of instruments was used to quantify the emissions of over 200 organic gases, including methane and volatile organic compounds (VOCs), and 9 inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. A gas chromatograph-mass spectrometer (GC-MS) provided extensive chemical detail of discrete air samples collected during a laboratory burn and was complemented by real-time measurements of organic and inorganic species via an open-path Fourier transform infrared spectrometer (OP-FTIR) and 3 different chemical ionization-mass spectrometers. These measurements were conducted in February 2009 at the U.S. Department …


Understanding The Interactions Of Carbon Nanotubes With Environmentally-Relevant Ions And Hydrogen Peroxide For Optical Sensing, Azhar Abdul Kareem Kamel Aug 2015

Understanding The Interactions Of Carbon Nanotubes With Environmentally-Relevant Ions And Hydrogen Peroxide For Optical Sensing, Azhar Abdul Kareem Kamel

Theses and Dissertations

Single-walled carbon nanotubes (SWNTs) have drawn great attention in chemical and biological optical sensor applications due to their novel near infrared (NIR) optical properties that are extremely sensitive to the surrounding environment. This dissertation is devoted to four research areas: 1) Redox chemistry of sodium dodecyl sulfate (SDS)-encased SWNTs with mercuric ions in an aqueous environment for optical sensing: Various factors including SDS and SWNT concentrations, different pH levels, and buffer constituents, have been systematically examined. SWNTs show high selectivity and sensitivity to Hg2+ over eleven other metal ions. The determined detection limit is 0.6 nM, lower than 10.0 nM, …


Rational Design Of Materials For The Protection Of Outdoor Metalworks, Natasja Alexandria Swartz Aug 2015

Rational Design Of Materials For The Protection Of Outdoor Metalworks, Natasja Alexandria Swartz

Dissertations and Theses

Protective coatings are commonly used to protect culturally significant works, such as outdoor sculptures and architectural elements. Given the valuable nature of such metalworks, there is a surprising lack of environmentally sustainable coatings available for their conservation. High performance clear coatings are not developed or thoroughly tested for compatibility and longevity on outdoor sculptures. This can make the implementation of both methods and materials, no matter how promising in a lab, a significant hurdle for the conservation science community. This dissertation work initially aims to replace high-VOC formulations such as acrylic lacquers and waxes currently used as protective coatings for …


Hexaniobate Nanopeapods: In Situ Deposition Of Magnetic-Noble Metal Nanoparticles Inside Preformed Nanoscrolls, Sarah P. Gauthier Aug 2015

Hexaniobate Nanopeapods: In Situ Deposition Of Magnetic-Noble Metal Nanoparticles Inside Preformed Nanoscrolls, Sarah P. Gauthier

LSU New Orleans Theses and Dissertations

An in situ deposition procedure was developed for the nanopeapod (NPP) formation of NiAu nanoparticles inside preformed acid-exchanged hexaniobate nanoscrolls (HNB). Metal salt precursors of Ni(acac)2 and HAuCl4∙3H2O were reduced in solution under mild synthetic conditions in the presence of the preformed acid-exchanged hexaniobate nanoscrolls. Two of the surfactants used for the formation of the nanoparticles were oleylamine and triphenylphosphine oxide (TTPO). Reaction conditions were studied and modified to produce well-defined NiAu@HNB NPP systems, with monodispersed particles evenly filling and orienting within the nanoscrolls. The synthetic parameters studied were both time and temperature, with the …


From Copper Zinc Tin Sulfur To Perovskites: Fabrication And Characterization Of New Generation Of Solar Cells, Sarah Wozny Aug 2015

From Copper Zinc Tin Sulfur To Perovskites: Fabrication And Characterization Of New Generation Of Solar Cells, Sarah Wozny

LSU New Orleans Theses and Dissertations

In 2013, the worldwide production of renewable electricity accounted for 22.1% of the total energy production with 0.9% coming from solar photovoltaics (PVs). Recently, there has been a growing interest for Cu2ZnSnS4 (CZTS) quaternary semiconductor due to the abundance and low cost of its precursors. Moreover, this chalcopyrite material has an ideal direct band gap around 1.5 eV, high absorption coefficient (α >104 cm-1) and high conductivity, making it suitable for nanostructured and dye-sensitized solar cell (DSSC) applications. Here, CZTS nanoparticles have been synthesized by pulsed laser deposition (PLD) and simultaneously deposited in the …


Inhibition Of The Dape-Encoded N-Succinyl- ʟ, ʟ-Diaminopimelic Acid Desuccinylase From Neisseria Meningitidis By ʟ-Captopril, Anna Starus, Boguslaw Nocek, Brian Bennett, James A. Larrabee, Daniel L. Shaw, Wisath Sae-Lee, Marie T. Russo, Danuta M. Gillner, Magdalena Makowska-Grzyska, Andzrej Joachimiak, Richard C. Holz Aug 2015

Inhibition Of The Dape-Encoded N-Succinyl- ʟ, ʟ-Diaminopimelic Acid Desuccinylase From Neisseria Meningitidis By ʟ-Captopril, Anna Starus, Boguslaw Nocek, Brian Bennett, James A. Larrabee, Daniel L. Shaw, Wisath Sae-Lee, Marie T. Russo, Danuta M. Gillner, Magdalena Makowska-Grzyska, Andzrej Joachimiak, Richard C. Holz

Physics Faculty Research and Publications

Binding of the competitive inhibitor ʟ-captopril to the dapE-encoded N-succinyl-ʟ, ʟ-diaminopimelic acid desuccinylase from Neisseria meningitidis (NmDapE) was examined by kinetic, spectroscopic, and crystallographic methods. ʟ-Captopril, an angiotensin-converting enzyme (ACE) inhibitor, was previously shown to be a potent inhibitor of the DapE from Haemophilus influenzae (HiDapE) with an IC50 of 3.3 μM and a measured Ki of 1.8 μM and displayed a dose-responsive antibiotic activity toward Escherichia coli. ʟ-Captopril is also a competitive inhibitor of NmDapE with a Ki of 2.8 μM. To examine the nature of the interaction …


Electrochemical Characterization Of Self-Assembled Monolayers On Gold Substrates Derived From Thermal Decomposition Of Monolayer-Protected Cluster Films, Michael C. Leopold, Tran T. Doan, Melissa J. Mullaney, Andrew F. Loftus, Christopher M. Kidd Aug 2015

Electrochemical Characterization Of Self-Assembled Monolayers On Gold Substrates Derived From Thermal Decomposition Of Monolayer-Protected Cluster Films, Michael C. Leopold, Tran T. Doan, Melissa J. Mullaney, Andrew F. Loftus, Christopher M. Kidd

Chemistry Faculty Publications

Networked films of monolayer-protected clusters (MPCs), alkanethiolate-stabilized gold nanoparticles, can be thermally decomposed to form stable gold on glass substrates that are subsequently modified with self-assembled monolayers (SAMs) for use as modified electrodes. Electrochemical assessment of these SAM-modified gold substrates, including double-layer capacitance measurements, linear sweep desorption of the alkanethiolates, and diffusional redox probing, all show that SAMs formed on gold supports formed from thermolysis of MPC films possess substantially higher defect density compared to SAMs formed on traditional evaporated gold. The density of defects in the SAMs on thermolyzed gold is directly related to the strategies used to assemble …


Di- And Trinuclear Mixed-Valence Copper Amidinate Complexes From Reduction Of Iodine, Andrew C. Lane, Charles L. Barnes, William E. Antholine, Denan Wang, Adam T. Fiedler, Justin R. Walensky Aug 2015

Di- And Trinuclear Mixed-Valence Copper Amidinate Complexes From Reduction Of Iodine, Andrew C. Lane, Charles L. Barnes, William E. Antholine, Denan Wang, Adam T. Fiedler, Justin R. Walensky

Chemistry Faculty Research and Publications

Molecular examples of mixed-valence copper complexes through chemical oxidation are rare but invoked in the mechanism of substrate activation, especially oxygen, in copper-containing enzymes. To examine the cooperative chemistry between two metals in close proximity to each other we began studying the reactivity of a dinuclear Cu(I) amidinate complex. The reaction of [(2,6-Me2C6H3N)2C(H)]2Cu2, 1, with I2 in tetrahydrofuran (THF), CH3CN, and toluene affords three new mixed-valence copper complexes [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I3)(THF)2, 2, [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I) (NCMe)2, 3, and [(2,6-Me2C6H3N)2C(H)]3Cu3(μ3-I)2, 4, respectively. The first two compounds were characterized by UV-vis and electron paramagnetic resonance spectroscopies, and their molecular structure was determined by X-ray crystallography. Both …


Comparison Of Ch∙∙O, Sh∙∙O, Chalcogen, And Tetrel Bonds Formed By Neutral And Cationic Sulfur-Containing Compounds, Steve Scheiner Aug 2015

Comparison Of Ch∙∙O, Sh∙∙O, Chalcogen, And Tetrel Bonds Formed By Neutral And Cationic Sulfur-Containing Compounds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The ability of neutral and charged S-compounds to form different sorts of noncovalent bonds is examined by ab initio calculations. Neutrals are represented by CH3SH and fluoro substituted FSCH3; cations are (CH3)3S+, CH3SH2+, and FHSCH3+. Each is paired with N-methylacetamide (NMA) whose O atom serves as common electron donor. Charged species engage in much stronger noncovalent bonds than do the neutral molecules, by as much as an order of magnitude. The strongest noncovalent bond for any system is a O∙∙SF chalcogen bond wherein the O lies directly opposite a S-F covalent bond, amounting to as much as 39 kcal/mol. Second …


Electrochemical Characterization Of Protein Adsorption Onto Yngrt-Au And Vlgxe-Au Surfaces, Hanna Trzeciakiewicz, Jose Esteves-Villanueva, Rania Soudy, Kamaljit Kaur, Sanela Martic-Milne Aug 2015

Electrochemical Characterization Of Protein Adsorption Onto Yngrt-Au And Vlgxe-Au Surfaces, Hanna Trzeciakiewicz, Jose Esteves-Villanueva, Rania Soudy, Kamaljit Kaur, Sanela Martic-Milne

Pharmacy Faculty Articles and Research

The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in …


Studies Of Optical And Electronic Properties Of Nanoparticles For Solar Energy Conversion, Caitlin Kruse, Libai Huang Aug 2015

Studies Of Optical And Electronic Properties Of Nanoparticles For Solar Energy Conversion, Caitlin Kruse, Libai Huang

The Summer Undergraduate Research Fellowship (SURF) Symposium

The higher energy needs for today's technological society requires sustainable and renewable energy source, such as solar energy. This study focuses on using semiconducting quantum dots and fluorescent dyes as light absorbers for solar energy conversion devices such as solar cells. Quantum dots are small nanocrystals (usually 2-10 nm in diameter) with tunable absorbing properties. The smaller the dot, the shorter the wavelength being absorbed. Quantum dots are extremely efficient light absorbers and emitters. Fluorescent dyes have a high quantum yield. In order to examine the energy conversion, cadmium selenide (CdSe) quantum dots and Rhodamine 6G (R6G) dye were spin …


Bio-Inspired Composite Hydrogels For Osteochondral Regenerative Engineering, Grant N. Gellert, Liangju Kuang, Chunhui Jiang, Nur P. Damayanti, Joseph Irudayaraj, Meng Deng Aug 2015

Bio-Inspired Composite Hydrogels For Osteochondral Regenerative Engineering, Grant N. Gellert, Liangju Kuang, Chunhui Jiang, Nur P. Damayanti, Joseph Irudayaraj, Meng Deng

The Summer Undergraduate Research Fellowship (SURF) Symposium

Treatment of osteochondral defects encompassing injury or degeneration to both the articular cartilage as well as the underlying subchondral bone presents a significant medical challenge. Current treatment options including autografts and allografts suffer from limited availability and risk of immunogenicity, respectively. The long term goal of this work is to develop an integrated scaffold system for treatment of osteochondral defects via in situ regeneration of bone, cartilage and the bone-cartilage interface. Hydrogels composed of polymer networks swollen in water provide an attractive biomaterial platform for regeneration of cartilage. In the present study, we have developed a novel composite hydrogel consisting …


Analysis Of The Fabrication Conditions In Organic Field-Effect Transistors, Rachel M. Rahn, Yan Zhao, Jianguo Mei Aug 2015

Analysis Of The Fabrication Conditions In Organic Field-Effect Transistors, Rachel M. Rahn, Yan Zhao, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polymer-based organic field-effect transistors have raised substantial awareness because they enable low-cost, solution processing techniques, and have the potential to be implemented in flexible, disposable organic electronic devices. The performance of these devices is highly dependent on the processing conditions, as well as the intrinsic properties of the polymer. Processing conditions play an important role in semiconductor film formation and device performance. These factors may provide an important link between structure and performance. In this study, an empirical analysis tool, Process Scout, was applied to assess processing factors such as polymer concentration and silicon modification. This sanctioned the creation of …


Development Of A Scalable Synthesis Of Hp-Β-Cd Pluronic Polyrotaxanes, Joseph L. Skulsky, Elizabeth A. Slepko, Bradley P. Loren, David H. Thompson Aug 2015

Development Of A Scalable Synthesis Of Hp-Β-Cd Pluronic Polyrotaxanes, Joseph L. Skulsky, Elizabeth A. Slepko, Bradley P. Loren, David H. Thompson

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polyrotaxanes are polymers that have macrocycles threaded onto them, analogous to beads threaded onto a string. These materials are used for a variety of different biomedical applications.1-3 The Thompson group has been developing 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) polyrotaxanes as therapeutics for the treatment of Niemann-Pick Type C (NPC) disease. NPC is a debilitating genetic disorder where cholesterol accumulates in the lysosomes of cells.4 Developing a scalable process is crucial for the advancement of these materials as NPC therapeutics. The goal of this project is to optimize the only protocol for the synthesis of HP-β-CD/Pluronic polyrotaxanes in order to develop a …


Deconstructing Cation-Pi Interactions: Understanding The Binding Energies Involved With Metal And Aromatic Amino Acid Residues, Jen E. Werner, Lyudmila V. Slipchenko, Yen Bui Aug 2015

Deconstructing Cation-Pi Interactions: Understanding The Binding Energies Involved With Metal And Aromatic Amino Acid Residues, Jen E. Werner, Lyudmila V. Slipchenko, Yen Bui

The Summer Undergraduate Research Fellowship (SURF) Symposium

The Effective Fragment Potential (EFP) method is a computationally efficient technique for describing non-covalent interactions, such as hydrogen bonding and van der Waals forces. Cation-pi interactions are a type of non-covalent interactions and are thought to be important in biological processes, such as permittivity of ion channels. The goal of our work is to establish that the EFP method reliably describes the strength, directionality, and composition of cation-pi interactions. Optimal geometries were found for a series of biologically relevant cations (K+, Li+, Na+, Ca2+, and Mg2+) and aryl moieties appearing …


Synthesis, Characterization, And Thermoelectric Properties Of Radical Siloxanes, Arnold J. Eng, Bryan Boudouris, Edward P. Tomlinson, Martha Emily Hay Aug 2015

Synthesis, Characterization, And Thermoelectric Properties Of Radical Siloxanes, Arnold J. Eng, Bryan Boudouris, Edward P. Tomlinson, Martha Emily Hay

The Summer Undergraduate Research Fellowship (SURF) Symposium

More than half of the annual energy consumption in the United States is lost as waste heat. Polymer-based thermoelectric devices have the potential to utilize this waste heat both sustainably and cost-effectively. Although conjugated polymers currently dominate research in organic thermoelectrics, the potential of using polymers with radical pendant groups have yet to be realized. These polymers have been found to be as conductive as pristine (i.e., not doped) poly(3-hexylthiophene) (P3HT), a commonly-used charge-transporting conjugated polymer. This could yield promising avenues for thermoelectric material design as radical polymers are more synthetically tunable and are hypothesized to have a high Seebeck …


Soluble Amyloid-Beta 42 Aggregates Stimulate Cellular Inflammation Independent Of Cd47, Sanjib Karki Aug 2015

Soluble Amyloid-Beta 42 Aggregates Stimulate Cellular Inflammation Independent Of Cd47, Sanjib Karki

Dissertations

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by the accumulation and deposition of aggregated amyloid-β protein (Aβ). Most of the studies indicate that Aβ1-42) and Aβ(1-40) play an important role in the neurodegenerative pathology in AD. A critical component of AD pathology is inflammation, which results from the activation of glial cells around the Aβ deposits. The goal of my dissertation research was to determine the role of Aβ aggregation in microglia-triggered inflammation and identify cellular components that mediate the inflammatory response. CD47 is a cellular receptor found on the microglia surface and it has been proposed to have …


Comparative Sorption Of Methylene Blue Onto Hydrophobic Clays, Alvaro D. Sponza, Natalia J. Fernandez, David Yang, Karla A. Ortiz, Abel E. Navarro Aug 2015

Comparative Sorption Of Methylene Blue Onto Hydrophobic Clays, Alvaro D. Sponza, Natalia J. Fernandez, David Yang, Karla A. Ortiz, Abel E. Navarro

Publications and Research

Chemical modifications of clay to remove methylene blue (MB) from aqueous solutions at room temperature were compared. Natural bentonite (NC) was modified by cation exchange with hexadecyltrimethylammonium chloride (HC), bencyltriethylammonium chloride (BC), and tetramethylammonium chloride (TC) to reverse the surface polarity of the hydrophilic bentonite. The adsorption of MB was studied and fitted by the adsorption theories of Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin. Equilibrium parameters were calculated, indicating that chemical modification did not improve the adsorption, due to the electrostatic adsorption mechanism. Specific surface area was determined, reporting the following trend: NC > TC > BC > HC. Isotherms show that TC is …


Weak Interactions Between Salmonella Enterica Flhb And Other Flagellar Export Apparatus Proteins Govern Type Iii Secretion Dynamics, Jonathan L. Mcmurry, Tohru Minamino, Yukio Furukawa, Joshua W. Francis Aug 2015

Weak Interactions Between Salmonella Enterica Flhb And Other Flagellar Export Apparatus Proteins Govern Type Iii Secretion Dynamics, Jonathan L. Mcmurry, Tohru Minamino, Yukio Furukawa, Joshua W. Francis

Faculty Articles

The bacterial flagellum contains its own type III secretion apparatus that coordinates protein export with assembly at the distal end. While many interactions among export apparatus proteins have been reported, few have been examined with respect to the differential affinities and dynamic relationships that must govern the mechanism of export. FlhB, an integral membrane protein, plays critical roles in both export and the substrate specificity switching that occurs upon hook completion. Reported herein is the quantitative characterization of interactions between the cytoplasmic domain of FlhB (FlhBC) and other export apparatus proteins including FliK, FlhAC and FliI. FliK and FlhAC bound …


Polycations Xxii. Ru(Bpy)2l2 And Ru(Phen)2l2 Systems With Cationic 4,4’-Bipyridine Ligands: Syntheses, Characteristics, And Interactions With Dna, Jasmine Hatcher, Freida Zavurov, Leslie Babukutty, Thomas Strekas, Robert Engel Aug 2015

Polycations Xxii. Ru(Bpy)2l2 And Ru(Phen)2l2 Systems With Cationic 4,4’-Bipyridine Ligands: Syntheses, Characteristics, And Interactions With Dna, Jasmine Hatcher, Freida Zavurov, Leslie Babukutty, Thomas Strekas, Robert Engel

Publications and Research

Earlier efforts have been concerned with the association of Ruthenium octahedral complexes with DNA. Since the positively charged ruthenium species has been found to associate with the electron rich major groove of double-stranded DNA, it was proposed the addition of cationic sites on the ligands attached to ruthenium would facilitate such association. Thus, we have synthesized several series of octahedral ruthenium complexes bearing ligands having within themselves cationic sites. These have been investigated in their interaction with calf thymus DNA using fluorescence titration analysis. The introduction of the cationic ligands has been found to exhibit enhanced association of the ruthenium …


The Influence Of Surface Chemistry On The Photoelectrochemical Properties Of Fes(2) Photoanodes, Qi Tong Aug 2015

The Influence Of Surface Chemistry On The Photoelectrochemical Properties Of Fes(2) Photoanodes, Qi Tong

Dissertations and Theses

The recurring theme of this dissertation is the correlation between FeS2 surface chemistry and key electrical and electronic properties of FeS2. Efforts have been made to identify and characterize the FeS2 surface, investigate the photoelectrochemistry of FeS2 photoanodes under anhydrous and anoxic conditions, and investigate the influence of deliberate surface chemistry on FeS2 photoelectrochemistry.

Infrared reflection-absorption spectroscopy (IRRAS) was used to investigate a thin adsorbate layer on pyrite. The results showed that the combination of angle-dependent studies and computational efforts are a powerful tool for characterizing the pyrite surface.

The photoelectrochemistry of FeS2 …


Evaluation Of 5 Μm Superficially Porous Particles For Capillary And Microfluidic Lc Columns, James Grinias, Robert T. Kennedy Aug 2015

Evaluation Of 5 Μm Superficially Porous Particles For Capillary And Microfluidic Lc Columns, James Grinias, Robert T. Kennedy

College of Science & Mathematics Departmental Research

Large-size (4–5 µm) superficially porous particles yield lower plate heights (e.g., the minimal reduced plate height or hmin ≈ 1.5) than fully porous particles of a similar size when packed into large-bore columns. This property allows for better chromatographic performance without the higher pressures required for smaller particles. This study explores the use of such particles in microfluidic LC columns where materials and fitting pressure limits can constrain the size of particle used. The theoretically predicted performance improvements compared to fully porous particles were not demonstrated in capillary columns (with hmin ≈ 2 for both particle types), in …


Plasminogen Activator Inhibitor-1 Inhibitors And Methods Of Use Thereof To Modulate Lipid Metabolism, Daniel A. Lawrence, Dudley Strickland, Jacqueline Cale, Enming Joe Su, Cory Emal, Mark Warnock Aug 2015

Plasminogen Activator Inhibitor-1 Inhibitors And Methods Of Use Thereof To Modulate Lipid Metabolism, Daniel A. Lawrence, Dudley Strickland, Jacqueline Cale, Enming Joe Su, Cory Emal, Mark Warnock

Patents

The invention relates to plasminogen activator-I (PAI-1) inhibitor compounds and uses thereof in the treatment of any disease or condition associated with elevated PAI-1. The invention includes, but is not limited to, the use of such compounds to modulate lipid metabolism and treat conditions associated with elevated PAI-1, cholesterol, or lipid levels.


Climatology And Atmospheric Chemistry Of The Non-Methane Hydrocarbons Ethane And Propane Over The North Atlantic, Detlev Helmig, Mauricio Muñoz, Jacques Hueber, Claudio Mazzoleni, Lynn Mazzoleni, Richard C. Owen, Maria Val-Martin, Paulo Fialho, Christian Plass-Duelmer, Paul I. Palmer, Alastair C. Lewis, Gabriele Pfister Aug 2015

Climatology And Atmospheric Chemistry Of The Non-Methane Hydrocarbons Ethane And Propane Over The North Atlantic, Detlev Helmig, Mauricio Muñoz, Jacques Hueber, Claudio Mazzoleni, Lynn Mazzoleni, Richard C. Owen, Maria Val-Martin, Paulo Fialho, Christian Plass-Duelmer, Paul I. Palmer, Alastair C. Lewis, Gabriele Pfister

Department of Chemistry Publications

A record spanning ten years of non-methane hydrocarbon (NMHC) data from the Pico Mountain Observatory (PMO), Pico Island, Azores, Portugal, was analyzed for seasonal NMHC behavior, atmospheric processing, and trends, focusing on ethane and propane. The location of this site in the central North Atlantic, at an elevation of 2225 m asl, allows these data to be used to investigate the background conditions and pollution transport events occurring in the lower free North Atlantic troposphere. The quantity ln([propane]/[ethane]) was used as an indicator of both photochemical processing and a marker for the occurrence of pollution transport events detected at the …


Controllable And Switchable Drug Delivery Of Ibuprofen From Temperature Responsive Composite Nanofibers, Toan Tran, Mariana Hernandez, Dhruvil Patel, Elena Burns, Vanessa Peterman, Ji Wu Aug 2015

Controllable And Switchable Drug Delivery Of Ibuprofen From Temperature Responsive Composite Nanofibers, Toan Tran, Mariana Hernandez, Dhruvil Patel, Elena Burns, Vanessa Peterman, Ji Wu

Chemistry: Faculty Publications (1990-2023)

Composited electrospun nanofibers made of temperature-responsive poly(N-isopropylacrylamide) (pNIPAM) and biodegradable poly (ε-caprolactone) (PCL) can be utilized for ‘on-demand’ and controlled drug release of ibuprofen without burst effect for potential pharmaceutical applications. Three types of nanofibers, PCL, pNIPAM and pNIPAM/PCL composite NFs containing ibuprofen were fabricated using electrospinning techniques. Ibuprofen release rates from PCL NFs are not affected by the temperature in the range of 22–34°C (less than 10%). In contrast, the ibuprofen release rates from pNIPAM NFs are very sensitive to the change in temperature, which is five times higher at 22°C compared to 34°C. However, there is a serious …


Scope And Mechanistic Analysis For Chemoselective Hydrogenolysis Of Carbonyl Compounds Catalyzed By A Cationic Ruthenium Hydride Complex With A Tunable Phenol Ligand, Nishantha Kumara Kalutharage, Chae S. Yi Aug 2015

Scope And Mechanistic Analysis For Chemoselective Hydrogenolysis Of Carbonyl Compounds Catalyzed By A Cationic Ruthenium Hydride Complex With A Tunable Phenol Ligand, Nishantha Kumara Kalutharage, Chae S. Yi

Chemistry Faculty Research and Publications

A cationic ruthenium hydride complex, [(C6H6)(PCy3)(CO)RuH]+BF4 (1), with a phenol ligand was found to exhibit high catalytic activity for the hydrogenolysis of carbonyl compounds to yield the corresponding aliphatic products. The catalytic method showed exceptionally high chemoselectivity toward the carbonyl reduction over alkene hydrogenation. Kinetic and spectroscopic studies revealed a strong electronic influence of the phenol ligand on the catalyst activity. The Hammett plot of the hydrogenolysis of 4-methoxyacetophenone displayed two opposite linear slopes for the catalytic system 1/p-X-C6H4OH (ρ = …


Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou Aug 2015

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks (MOFs) are synthetic materials made of a cage-like lattice of metal nodes connected by organic linkers. The pores between the nodes define the characteristics of the material. A MOF, MIL-101, has shown great capacity in the adsorption of carbon dioxide and methane, as well as in hydrogenation catalysis with palladium. While there has been success in synthesizing MIL-101 and other MOFs, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. Using MIL-101 as a prototypical …