Polaronic Semiconductor Behavior Of Long-Range Charge Transfer In Dna Oligomers In Solution: Controlling Barriers To Long-Distance Radical Cation Migration In Dna With Thymine Analogs, 2014 The University of Akron
Polaronic Semiconductor Behavior Of Long-Range Charge Transfer In Dna Oligomers In Solution: Controlling Barriers To Long-Distance Radical Cation Migration In Dna With Thymine Analogs, Abraham Joy
Abraham Joy
A series of anthraquinone-linked DNA oligonucleotides was prepared and the efficiency of long-distance radical cation migration was measured. In one set of oligonucleotides, two GG steps are separated by either a TATA or an ATAT bridge. In these two compounds, the efficiency of radical cation migration from GG to GG differs by more than an order of magnitude. Replacement of the thymines in the TATA or ATAT bridges with 3-methyl-2-pyridone (t, a thymine analog) results in the much more efficient radical cation migration across the bridge in both cases. This is attributed to a decrease in the oxidation potential of …
Chiral Photochemistry Within Zeolites, 2014 The University of Akron
Chiral Photochemistry Within Zeolites, Abraham Joy
Abraham Joy
Chiral induction of chemical reactions continues to be one of the main concerns of chemists. While basic rules of chiral induction of thermal reactions have been reasonably established, the same is not true of photochemical reactions. Short excited state lifetime and low activation energies for reactions in the excited state(s) leave very little room for manipulating the diastereomeric transition states. Yet impressive chiral induction of photochemical reactions in the solid state has been achieved. On the other hand, chiral induction of photoreactions of organic molecules in solution continues to be inefficient at ambient conditions. We are exploring the possibility of …
Control Of Surface Chemistry, Substrate Stiffness, And Cell Function In A Novel Terpolymer Methacrylate Library, 2014 The University of Akron
Control Of Surface Chemistry, Substrate Stiffness, And Cell Function In A Novel Terpolymer Methacrylate Library, Abraham Joy
Abraham Joy
A focused library of methacrylate terpolymers was synthesized to explore the effects of varying surface chemistry and adhesive peptide ligands on cell function. The chemical diversity of methacrylate monomers enabled construction of a library of polymers in which one can systematically vary the chemical composition to achieve a wide range of contact angle, Young's modulus, and Tg values. Furthermore, the materials were designed to allow surface immobilization of bioactive peptides. We then examined the effects of these material compositions on protein adsorption and cell attachment, proliferation, and differentiation. We observed that chemical composition of the polymers was an important determinant …
Chiral Photochemistry, 2014 The University of Akron
Chiral Photochemistry, Abraham Joy
Abraham Joy
Chiral induction of chemical reactions continues to be one of the main concerns of chemists. While basic rules of chiral induction of thermal reactions have been reasonably established, the same is not true of photochemical reactions. Short excited state lifetime and low activation energies for reactions in the excited state(s) leave very little room for manipulating the diastereomeric transition states. Yet impressive chiral induction of photochemical reactions in the solid state has been achieved. On the other hand, chiral induction of photoreactions of organic molecules in solution continues to be inefficient at ambient conditions. We are exploring the possibility of …
Halogenated Squaraine Dyes As Potential Photochemotherapeutic Agents. Synthesis And Study Of Photophysical Properties And Quantum Efficiencies Of Singlet Oxygen Generation*, 2014 The University of Akron
Halogenated Squaraine Dyes As Potential Photochemotherapeutic Agents. Synthesis And Study Of Photophysical Properties And Quantum Efficiencies Of Singlet Oxygen Generation*, Abraham Joy
Abraham Joy
The photophysical properties of two pairs of squaraine molecules where two oxygen atoms in a squaraine bridge are replaced with sulfur atoms are investigated. This substitution leads to an inversion of the lowest singlet π−π* electronic transition by an n−π* transition, effectively reducing the energy difference between singlet and triplet states and significantly increasing the intersystem crossing efficiency without the use of “heavy atoms”. Experimental results, in agreement with quantum chemical calculations, show near-unity values for triplet quantum yield and singlet oxygen generation quantum yield for sulfur-containing squaraines, which are potentially useful for two-photon photodynamic therapy.Keywords (keywords): squaraine dyes; intersystem …
Effect Of Nozzle Geometry On Jet Bed Interaction: Experiments With Commercial Scale Nozzles And Eroded Nozzles, 2014 The University of Western Ontario
Effect Of Nozzle Geometry On Jet Bed Interaction: Experiments With Commercial Scale Nozzles And Eroded Nozzles, Nicholas A. Prociw
Electronic Thesis and Dissertation Repository
Liquid injection into fluidized bed reactors has several industrial applications, such as Fluid Catalytic Cracking, Gas Phase Polyethylene production, and Fluid Coking. High quality liquid distribution is essential to maximize the yield of desirable products, and minimize agglomeration.
The objectives of this thesis are: to develop a method that measures the rate of liquid released from agglomerates formed as a result of liquid injection into a fluidized bed; to use this method to determine the effect of internal erosion on nozzle performance; and to compare the performance of current commercial spray nozzles to nozzles with altered geometries. To achieve these …
Correlation Between Microstructure And Thermionic Electron Emission From Os-Ru Thin Films On Dispenser Cathodes, 2014 University of Kentucky
Correlation Between Microstructure And Thermionic Electron Emission From Os-Ru Thin Films On Dispenser Cathodes, Phillip D. Swartzentruber, Thomas John Balk, Michael P. Effgen
Chemical and Materials Engineering Faculty Publications
Osmium-ruthenium films with different microstructures were deposited onto dispenser cathodes and subjected to 1000 h of close-spaced diode testing. Tailored microstructures were achieved by applying substrate biasing during deposition, and these were evaluated with scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray spectroscopy before and after close-spaced diode testing. Knee temperatures determined from the close-spaced diode test data were used to evaluate cathode performance. Cathodes with a large {10-11} Os-Ru film texture possessed comparatively low knee temperatures. Furthermore, a low knee temperature correlated with a low effective work function as calculated from the close-spaced diode data. It is proposed …
Solvent System Selection For Xylooligosaccharides Separation By Centrifugal Partition Chromatography Using Conductor-Like Screening Model For Real Solvents, 2014 Purdue University
Solvent System Selection For Xylooligosaccharides Separation By Centrifugal Partition Chromatography Using Conductor-Like Screening Model For Real Solvents, He Zhang
Open Access Theses
The production of value-added, bio-based industrial commodity chemicals is an important area in science right now and this study provides an initial step in the recovery of bio-based chemicals from hemicellulose. Hemicellulose is a long chain polymer mostly consisting of xylose, which is a five-carbon sugar, and a variety of other compounds that are ubiquitous in plant life. The hemicellulose polymer chain can be depolymerized into smaller components, called xylooligosaccharides (XOS) with different chain lengths of xylose linked by beta-1-4 glycosidic bonds, using either hot water, or dilute sulfuric acid. The xylooligosaccharides can then be purified from one another from …
Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, 2014 Purdue University
Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan
Open Access Theses
The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles, 2014 Purdue University
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles, Bethlehem G. Negash
Open Access Theses
Research in thin film solar cells applies novel techniques to synthesize cost effective and highly efficient absorber materials in order to generate electricity directly from solar energy. Of these materials, copper zinc tin sulfoselenide (Cu2ZnSn(SxSe1-x) 4) nanoparticles have shown great promise in solar cell applications due to optimal material properties as well as low cost & relative abundance of materials.1,2 Sulfoselenide nanoparticles have also a broader impact in other industries including electronics3, LED 4, and biomedical research5. Of the many routes of manufacturing these class of semiconductors, …
Fundamental Studies On Copper Zeolites For Catalytic No X Abatement, 2014 Purdue University
Fundamental Studies On Copper Zeolites For Catalytic No X Abatement, Anuj Arun Verma
Open Access Dissertations
Stringent regulations in mobile NOx emissions have resulted in the development of Standard Selective Catalytic Reduction (SCR) as the dominant NOx abatement technology in lean burn diesel engines. Standard SCR is a reaction of nitric oxide (NO) with ammonia (NH3), in the presence of oxygen (O 2) to form nitrogen (N2) and water (H2O). Copper containing zeolites show commercially viable SCR performance. Cu-SSZ-13 (CHA framework), a member of this family, is a preferred catalyst for SCR applications because it shows exceptional hydrothermal stability in addition to commercially viable SCR performance. Our work focuses …
Optimal Aggregation Of Fcεri With A Structurally Defined Trivalent Ligand Overrides Negative Regulation Driven By Phosphatases, 2014 Missouri University of Science and Technology
Optimal Aggregation Of Fcεri With A Structurally Defined Trivalent Ligand Overrides Negative Regulation Driven By Phosphatases, Avanika Mahajan, Dipak Barua, Patrick Cutler, Diane S. Lidke, Flor A. Espinoza, Carolyn Pehlke, Rachel Grattan, Yuko Kawakami, Chang-Shung Tung, Andrew R. M. Bradbury, William S. Hlavacek, Bridget S. Wilson
Chemical and Biochemical Engineering Faculty Research & Creative Works
To investigate why responses of mast cells to antigen-induced IgE receptor (FcεRI) aggregation depend nonlinearly on antigen dose, we characterized a new artificial ligand, DF3, through complementary modeling and experimentation. This ligand is a stable trimer of peptides derived from bacteriophage T4 fibritin, each conjugated to a hapten (DNP). We found low and high doses of DF3 at which degranulation of mast cells sensitized with DNP-specific IgE is minimal, but ligand-induced receptor aggregation is comparable to aggregation at an intermediate dose, optimal for degranulation. This finding makes DF3 an ideal reagent for studying the balance of negative and positive signaling …
Pharmacokinetic Characterization Of Procoagulation Proteins, 2014 University of Nebraska-Lincoln
Pharmacokinetic Characterization Of Procoagulation Proteins, Nicholas C. Vanderslice
Department of Chemical and Biomolecular Engineering: Theses and Student Research
The cessation of bleeding in mammals occurs due to a well-conserved sequence of protein activation known as the coagulation cascade. However, people who have a deficiency in one or more proteins in this cascade, whether due to genetics or blood loss, struggle to maintain hemostasis. In order to aid patients in the restoration of hemostasis, exogenous proteins are often administered in response to bleeding events. However, these proteins are limited and costly due to limited supply of donor blood available for the production of plasma-derived proteins and the high cost of mammalian cell bio-reactors required for the production of recombinant …
Measurement And Modeling Of Fire Behavior In Leaves And Sparse Shrubs, 2014 Brigham Young University - Provo
Measurement And Modeling Of Fire Behavior In Leaves And Sparse Shrubs, Dallan R. Prince
Theses and Dissertations
Wildland fuels and fire behavior have been the focus of numerous studies and models which provide operational support to firefighters. However, fuel and fire complexity in live shrubs has resulted in unexpected and sometimes aggressive fire behavior. The combustion of live fuels was studied and modeled, and the results were assimilated into a shrub-scale fire behavior model which assumes fire spread by flame-fuel overlap. Fire spread models have usually assumed that radiation heat transfer is responsible for driving fire spread, but that assumption is a topic of continuing debate, and appears to contradict some experimental observations. A convection-based shrub-scale fire …
Effects Of Oxygen Coverage And Hydrated Proton Model On The Dft Calculation Of Oxygen Reduction Pathways On The Pt(111) Surface, 2014 College of Chemistry and Chemical Engineering, Hunan University of Arts and Science, Changde 415000, Hunan, China;College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China;
Effects Of Oxygen Coverage And Hydrated Proton Model On The Dft Calculation Of Oxygen Reduction Pathways On The Pt(111) Surface, Li-Hui Ou, Sheng-Li Chen
Journal of Electrochemistry
DFT calculation is used to study various possible steps in the oxygen reduction reaction (ORR), including the adsorption and dissociation process of O2 and the serial protonation process of dissociated products to form H2O on the Pt(111) surface. By using slabs of different sizes, and different numbers of pre-adsorbed oxygen atoms, the coverage effects on the pathways are investigated. The calculated results using different hydrated proton models are also compared. It is shown that the initial step of the ORR is the formation of a protonated end-on chemisorbed state of OOH*, which can transform to an unprotonated …
The Ionic Diffusion Model For The Solid Oxide Cathode And Its Verification By The Electrolysis Of Ta2O5 In Molten Cacl2, 2014 College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China;
The Ionic Diffusion Model For The Solid Oxide Cathode And Its Verification By The Electrolysis Of Ta2O5 In Molten Cacl2, Hua-Lin Chen, Zhi-Yong Wang, Xian-Bo Jin, George Z. Chen
Journal of Electrochemistry
The deoxidation speed of a solid oxide cathode in molten CaCl2 can be estimated by the PRS steady diffusion model of O2-, which correlates the deoxidation speed with the precursor porosity, P, the metal-to-oxide molar volume ratio, R, and the cathode volume shrinkage S. The PRS model indicates that the porosity of the oxide cathode has important influence on the deoxidation speed, and provides a very simple equation for the prediction of the optimal cathode porosity. For the electrolysis of Ta2O5, the porosity of the cathode is better to be …
Horseradish Peroxidase-Attapulgite Clay Nanocomposites: Fabrication And Application To Sensing The Extracellular H2O2 Released From Cells, 2014 Jiangsu Key Laboratory of New Power Batteries, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210046, China;
Horseradish Peroxidase-Attapulgite Clay Nanocomposites: Fabrication And Application To Sensing The Extracellular H2O2 Released From Cells, Ping Wu, Chen-Xin Cai
Journal of Electrochemistry
The nanostructured attapulgite clay was employed as a support matrix for immobilizing horseradish peroxidase (HRP). FTIR and electrochemical methods demonstrated that HRP had been effectively assembled on attapulgite surface with the formation of HRP-attapulgite nanocomposites. The HRP-attapulgite hybrid was deposited on the glassy carbon (GC) electrode forming the HRP-attapulgite/GC electrode. Cyclic voltammetric results showed a pair of well-defined redox peaks, which were ascribed to direct electron transfer (DET) of HRP, with the formal potential E0′ = -335 mV (vs. SCE) in the phosphate buffer solution (PBS, pH 7.0). The dependence of E0′ on solution pH indicated …
Plasmonic Optical Sensors: Performance Analysis And Engineering Towards Biosensing, 2014 The University of Western Ontario
Plasmonic Optical Sensors: Performance Analysis And Engineering Towards Biosensing, Peipei Jia
Electronic Thesis and Dissertation Repository
Surface plasmon resonance (SPR) sensing for quantitative analysis of chemical reactions and biological interactions has become one of the most promising applications of plasmonics. This thesis focuses on performance analysis for plasmonic sensors and implementation of plamonic optical sensors with novel nanofabrication techniques.
A universal performance analysis model is established for general two-dimensional plasmonic sensors. This model is based on the fundamental facts of surface plasmon theory. The sensitivity only depends on excitation light wavelength as well as dielectric properties of metal and dielectrics. The expression involves no structure-specified parameters, which validates this formula in broad cases of periodic, quasiperiodic …
Calculated Vs. Experimental Values For Volume And Surface Resistivity In Various Polymer Compounds, 2014 University of Wisconsin - Whitewater
Calculated Vs. Experimental Values For Volume And Surface Resistivity In Various Polymer Compounds, Megan Webster
Pursuit - The Journal of Undergraduate Research at The University of Tennessee
Versatile due to their resistance to high stress environments including but not limited to extreme temperature, pressure, and stress, polymers additionally have many uses in electrical applications wherein antistatic or conductive properties are preferential, i.e. conductive seals, oil pipeline spheres, and gaskets, to name a few. Being a complex material, many factors may affect the electrical resistivity of a given polymer compound including type and amount of carbon black, type of rubber, cure time and temperature, and dispersion, amongst other factors. External conditions such as relative humidity and temperature also play key roles. This paper will analyze five different rubber …
Chemoorganotrophic Bioleaching Of Olivine For Nickel Recovery, 2014 University of Guelph
Chemoorganotrophic Bioleaching Of Olivine For Nickel Recovery, Yi Wai Chiang, Rafael M. Santos, Aldo Van Audenaerde, Annick Monballiu, Tom Van Gerven, Boudewijn Meesschaert
Faculty Publications and Scholarship
Bioleaching of olivine, a natural nickel-containing magnesium-iron-silicate, was conducted by applying chemoorganotrophic bacteria and fungi. The tested fungus, Aspergillus niger, leached substantially more nickel from olivine than the tested bacterium, Paenibacillus mucilaginosus. Aspergillus niger also outperformed two other fungal species: Humicola grisae and Penicillium chrysogenum. Contrary to traditional acid leaching, the microorganisms leached nickel preferentially over magnesium and iron. An average selectivity factor of 2.2 was achieved for nickel compared to iron. The impact of ultrasonic conditioning on bioleaching was also tested, and it was found to substantially increase nickel extraction by A. niger. This is credited to an enhancement …