Size And Site Dependence Of The Catalytic Activity Of Iridium Clusters Towards Ethane Dehydrogenation,
2016
Central Washington University
Size And Site Dependence Of The Catalytic Activity Of Iridium Clusters Towards Ethane Dehydrogenation, Yingbin Ge, Hao Jiang, Russell Kato, Prasuna Gummagatta
All Faculty Scholarship for the College of the Sciences
This research focuses on optimizing transition metal nanocatalyst immobilization and activity to enhance ethane dehydrogenation. Ethane dehydrogenation, catalyzed by thermally stable Irn (n = 8, 12, 18) atomic clusters that exhibit a cuboid structure, was studied using the B3LYP method with triple-ζ basis sets. Relativistic effects and dispersion corrections were included in the calculations. In the dehydrogenation reaction Irn + C2H6 → H−Irn−C2H5 → (H)2−Irn−C2H4, the first H-elimination is the rate-limiting step, primarily because the reaction releases sufficient heat to facilitate …
Kinetics And Reaction Mechanisms For Methylidyne Radical Reactions With Small Hydrocarbons,
2016
Florida International University
Kinetics And Reaction Mechanisms For Methylidyne Radical Reactions With Small Hydrocarbons, Joao Marcelo Lamim Ribeiro
FIU Electronic Theses and Dissertations
The chemical evolution with respect to time of complex macroscopic mixtures such as interstellar clouds and Titan’s atmosphere is governed via a mutual competition between thousands of simultaneous processes, including thousands of chemical reactions. Chemical kinetic modeling, which attempts to understand their macroscopic observables as well as their overall reaction mechanism through a detailed understanding of their microscopic reactions and processes, thus require thousands of rate coefficients and product distributions. At present, however, just a small fraction of these have been well-studied and measured; in addition, at the relevant low temperatures, such information becomes even more scarce. Due to the …
P-26 Detection Of Counterfeit Antimalarial Drugs By Sers,
2016
Andrews University
P-26 Detection Of Counterfeit Antimalarial Drugs By Sers, Getahun Merga, P. Shepard, M. Trujillo, J. Camden
Celebration of Research and Creative Scholarship
Substandard antimalarial drugs are a major problem to the health of citizens in developing countries, and it is likely that the problem persists due to the lack of means to detect substandard drugs. Various colorimetric techniques have been implemented to determine if a drug contains the stated active ingredient or not, but vibrational spectroscopies such as NIR and Raman can be used to more reliably quantify the amount of active ingredient. The use of Raman, however, has been limited by the presence of significant sample fluorescence that interferes with detection of the SERS signals of the active ingredients. Thus, we …
Giant Electrorheological Fluids With Ultrahigh Electrorheological Efficiency Based On A Micro/Nano Hybrid Calcium Titanyl Oxalate Composite,
2016
Chinese Academy of Sciences
Giant Electrorheological Fluids With Ultrahigh Electrorheological Efficiency Based On A Micro/Nano Hybrid Calcium Titanyl Oxalate Composite, Jinghua Wu, Zhenyang Song, Fenghua Liu, Jianjun Guo, Yuchuan Cheng, Shengqian Ma, Gaojie Xu
Chemistry Faculty Publications
A novel micro/nanoparticle hybrid calcium titanyl oxalate electrorheological (ER) material composed of micron-sized spindly particles and nanometer-sized irregular particles was successfully fabricated. The giant ER fluid based on the composite exhibits enhanced not only yield stress but also low field-off viscosity, thereby resulting in an ultrahigh ER efficiency that greatly exceeds that of any existing giant ER (GER) material. The synergistic effect between the spindly microparticles and irregular nanoparticles discovered in this study suggests a promising method for solving the long-standing ER efficiency problems. Moreover, the one-step synthesis approach presented in this work can be readily expanded for mass production …
The Optimization Of Pressure Cycling Technology (Pct) For Differential Extraction Of Sexual Assault Casework,
2016
Florida International University
The Optimization Of Pressure Cycling Technology (Pct) For Differential Extraction Of Sexual Assault Casework, Vanessa Martinez
FIU Electronic Theses and Dissertations
A two-step protocol has been devised as a rapid and selective alternative to conventional differential extraction techniques with an increased recovery of DNA. The protocol involves pressure cycling with the Barocycler® NEP 2320 from Pressure Biosciences. Inc. in alkaline conditions for epithelial cell lysis and removal. This step is followed by alkaline lysis at 95º C for extraction of sperm cell DNA. At 1:1 or 2:1 female to male cell ratios, high selectivity and complete separation can be achieved. But at higher ratios, male allelic dropout is observed. This protocol has been modified to generate a clean male …
Carotenoids And Fatty Acids In Early Lactation: A Study Of A Peruvian Population,
2016
Florida International University
Carotenoids And Fatty Acids In Early Lactation: A Study Of A Peruvian Population, Vanesa Mendez
FIU Electronic Theses and Dissertations
Lipid soluble carotenoids are micronutrients present in human milk that serve as precursors of vitamin A and also play an important role protecting cells from damage arising from photooxidative processes and reactive oxygen species. Fatty acids comprise about 3-5% of human milk and are mainly present as triglycerides. They are a major energy source for the infant and are necessary to support cell growth required for normal development and maturation of critical organs. Transport of carotenoids into milk has been little studied and there has been no previous investigation of the relationship of carotenoid transport with that of individual fatty …
Synthesis And Characterization Of Novel Polyurethanes And Polyimides,
2016
University of South Florida
Synthesis And Characterization Of Novel Polyurethanes And Polyimides, Kenneth Kull
USF Tampa Graduate Theses and Dissertations
Four novel high performance soft thermoplastic polyurethane elastomers utilizing methylene bis(4-cyclohexylisocyanate) as a hard segment, 1,4 butanediol as a chain extender and modified low crystallinity carbonate copolymer as a soft segment were synthesized. The samples were characterized by infrared spectroscopy (FTIR), tensile, elongation, hardness, abrasion resistance and atomic force microscopy (AFM). SAXS data shows evidence of an interdomain "center-to-center" distance of 45Å. DSC traces show evidence of one glass transition temperature and a weak melting region. DMA analysis reveals a low temperature secondary relaxation and the glass to rubber transition followed by a rubbery plateau. All samples demonstrated the ability …
The Application Of Electrochemical Impedance Spectroscopy To Immediately Diagnose The Protective Quality Of Coatings On Artistic And Architectural Metalwork,
2016
Portland State University
The Application Of Electrochemical Impedance Spectroscopy To Immediately Diagnose The Protective Quality Of Coatings On Artistic And Architectural Metalwork, Kathryn Nicole Hosbein
Dissertations and Theses
Corrosion is a spontaneous process that causes irreversible damage to nearly all metals, which has world-wide implications for architectural and artistic metalwork, such as bridges, buildings, airplanes and sculptures. Protective coatings such as wax, paint, or polymeric clear coatings are used to prolong the lifetime of metals such as steel and bronze. Unfortunately, these coatings fail over time due to oxidative damage by UV rays and by failure to exclude water that can carry salts and pollutants that cause corrosion of the underlying substrate. The current method of coating assessment is visual inspection but when coating failure is detected at …
Molecular Tetrapods For Optoelectronic Applications,
2016
University of New Mexico
Molecular Tetrapods For Optoelectronic Applications, Jianzhong Yang
Chemistry and Chemical Biology ETDs
In this dissertation, several molecular tetrapods were synthesized for optoelectronic applications. In the first two sections, two tetrapodal breakwater-like small molecules: SO and SFBTD were synthesized and characterized. Absorption, X-ray scattering and differential scanning calorimetry experiments indicate crystalline nature of these compounds but slow crystallization kinetics. Solar cells employing SO or SFBTD and phenyl-C61-butyric acid methyl ester (PCBM) were fabricated and evaluated. Relatively low performance was obtained mainly due to the lack of appropriate phase separation, which was caused by molecularly mixed blends with PCBM. The molecularly mixed blends is the result of slow crystallization …
Structural Elements Of An Nrps Cyclization Domain And Its Intermodule Docking Domain,
2016
Bryn Mawr College
Structural Elements Of An Nrps Cyclization Domain And Its Intermodule Docking Domain, Daniel P. Dowling, Yan Kung, Anna K. Croft, Koli Taghizadeh, Wendy L. Kelly, Christopher T. Walsh, Catherine L. Drennan
Chemistry Faculty Research and Scholarship
Epothilones are thiazole-containing natural products with anticancer activity that are biosynthesized by polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) enzymes EpoA–F. A cyclization domain of EpoB (Cy) assembles the thiazole functionality from an acetyl group and L-cysteine via condensation, cyclization, and dehydration. The PKS carrier protein of EpoA contributes the acetyl moiety, guided by a docking domain, whereas an NRPS EpoB carrier protein contributes L-cysteine. To visualize the structure of a cyclization domain with an accompanying docking domain, we solved a 2.03-Å resolution structure of this bidomain EpoB unit, comprising residues M1-Q497 (62 kDa) of the 160-kDa EpoB protein. We find …
Interspecies Comparison Of Peptide Substrate Reporter Metabolism Using Compartment-Based Modeling [Post-Print],
2016
Trinity College, Hartford Connecticut
Interspecies Comparison Of Peptide Substrate Reporter Metabolism Using Compartment-Based Modeling [Post-Print], Allison Tierney, Nhat Pham, Kunwei Yang, Brooks Emerick, Michelle Kovarik
Faculty Scholarship
Peptide substrate reporters are fluorescently labeled peptides that can be acted upon by one or more enzymes of interest. Peptide substrates are readily synthesized and more easily separated than full-length protein substrates; however, they are often more rapidly degraded by peptidases. As a result, peptide reporters must be made resistant to proteolysis in order to study enzymes in intact cells and lysates. This is typically achieved by optimizing the reporter sequence in a single cell type or model organism, but studies of reporter stability in a variety of organisms are needed to establish the robustness and broader utility of these …
Towards An Understanding Of The Propensity For Crystalline Hydrate Formation By Molecular Compounds,
2016
University of Limerick
Towards An Understanding Of The Propensity For Crystalline Hydrate Formation By Molecular Compounds, Alankriti Bajpai, Hayley S Scott, Tony Pham, Kai-Jie Chen, Brian Space, Matteo Lusi, Miranda L Perry, Michael J Zaworotko
Chemistry Faculty Publications
Hydrates are technologically important and ubiquitous yet they remain a poorly understood and understudied class of molecular crystals. In this work, we attempt to rationalize propensity towards hydrate formation through crystallization studies of molecules that lack strong hydrogen-bond donor groups. A Cambridge Structural Database (CSD) survey indicates that the statistical occurrence of hydrates in 124 molecules that contain five- and six-membered N-heterocyclic aromatic moieties is 18.5%. However, hydrate screening experiments on a library of 11 N-heterocyclic aromatic compounds with at least two acceptor moieties and no competing hydrogen-bond donors or acceptors reveals that over 70% of this group …
Self-Aligned Carbon Nanotube Yarns For Multifunctional Optoelectronic Applications,
2016
Brac University
Self-Aligned Carbon Nanotube Yarns For Multifunctional Optoelectronic Applications, Md. Jasim Uddin, Glenn Grissom, Miguel Leal, Veronica Galvez, Tarek Trad, Ahmed Touhami, Nazmul Islam, Jason Parsons, H. Justin Moore
Chemistry Faculty Publications and Presentations
In this work, the morphology and electrocatalytic features of carbon nanotube yarns at the structural level allow for enhanced photoconversion efficiency. The energy conversion of electronhole pairs within the carbon nanotube yarn (CNY) due to the functionalization with nanostructured photoactive TiO₂ phases is remarkable. A well oriented anatase TiO₂ thin layer (approximately 100 nm) forms at the interfaces of CNY and TiO₂ mesoporous film when the sample is precoated and annealed at 350ºC. Field Emission Scanning Electron Microscopy (FESEM) images show the integrity and homogeneity of the TiO₂ surface, which is indicative of the overall durability of the CNY-based dye …
Version 1.3 Aim Sofie Measured Methane (Ch4): Validation And Seasonal Climatology,
2016
Old Dominion University
Version 1.3 Aim Sofie Measured Methane (Ch4): Validation And Seasonal Climatology, P. P. Rong, J. M. Russell Iii, B. T. Marshall, D. E. Siskind, M. E. Hervig, L. L. Gordley, P. F. Bernath, K. A. Walker
Chemistry & Biochemistry Faculty Publications
The V1.3 methane (CH4) measured by the Aeronomy of Ice in the Mesosphere (AIM) Solar Occultation for Ice Experiment (SOFIE) instrument is validated in the vertical range of ~25–70 km. The random error for SOFIE CH4 is ~0.1–1% up to ~50 km and degrades to ~9% at ∼ 70 km. The systematic error remains at ~4% throughout the stratosphere and lower mesosphere. Comparisons with CH4 data taken by the SCISAT Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) and the Envisat Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) show an agreement within ~15% in the altitude range ~30–60 …
Synthesis Of Orthogonally Protected Thioamide Dipeptides For Use In Solid-Phase Peptide Synthesis,
2016
Technological University Dublin
Synthesis Of Orthogonally Protected Thioamide Dipeptides For Use In Solid-Phase Peptide Synthesis, Fintan Kelleher, Kim Manzor
Articles
Orthogonally protected thioamide-containing dipeptides were efficiently and cleanly prepared from the precursor dipeptides using Curphey’s method (P4S10, hexamethyldisiloxane (HMDO), reflux, DCM) in 67-96% isolated yield. This was in contrast to the use of Lawesson’s or Berzelius’ reagents where significant issues with reaction non-completion, decomposition and purification were observed. Subsequent clean removal of the dipeptides’ t-butyl ester protecting groups gave thioamide dipeptide acids which were suitable for use in solid-phase peptide synthesis (SPPS).
Conformational States Of Cytochrome P450 Oxidoreductase Evaluated By Förster Resonance Energy Transfer Using Ultrafast Transient Absorption Spectroscopy,
2016
Marquette University
Conformational States Of Cytochrome P450 Oxidoreductase Evaluated By Förster Resonance Energy Transfer Using Ultrafast Transient Absorption Spectroscopy, Elizaveta A. Kovrigina, Brian Pattengale, Chuanwu Xia, Azamat R. Galiakhmetov, Jier Huang, Jung Ja Kim, Evgueni Kovrigin
Chemistry Faculty Research and Publications
NADPH-cytochrome P450 oxidoreductase (CYPOR) was shown to undergo large conformational rearrangements in its functional cycle. Using a new Förster resonance energy transfer (FRET) approach based on femtosecond transient absorption spectroscopy (TA), we determined the donor–acceptor distance distribution in the reduced and oxidized states of CYPOR. The unmatched time resolution of TA allowed the quantitative assessment of the donor–acceptor FRET, indicating that CYPOR assumes a closed conformation in both reduced and oxidized states in the absence of the redox partner. The described ultrafast TA measurements of FRET with readily available red–infrared fluorescent labels open new opportunities for structural studies in chromophore-rich …
Thermolysis Of Hypervalent Iodine Complexes: Synthesis Of Fluorinated Radiotracers For Positron Emission Tomography And Synthesis Of Quaternary Α-Alkyl Α-Aryl Amino Acids,
2016
University of Nebraska-Lincoln
Thermolysis Of Hypervalent Iodine Complexes: Synthesis Of Fluorinated Radiotracers For Positron Emission Tomography And Synthesis Of Quaternary Α-Alkyl Α-Aryl Amino Acids, Jayson J. Kempinger
Department of Chemistry: Dissertations, Theses, and Student Research
Hypervalent iodine complexes can be used to deliver a variety of functional groups to arenes. Delivery of fluorine‑18, in a manner compatible with positron emission tomography (PET), is especially attractive. VizamylTM, an injectable solution of [18F]Flutemetamol, is currently used to diagnose and monitor the progression of Alzheimer’s Disease (AD), the most common form of dementia. AD affects 47.5 million people across the world as of 2015, and is projected to affect 1 in 85 people by 2050. An improved radiosynthesis of [18F]Flutemetamol via a diaryliodonium salt is described. The use of nonpolar solvents minimizes …
Strategies For The Production Of Cell Wall-Deconstructing Enzymes In Lignocellulosic Biomass And Their Utilization For Biofuel Production,
2016
Michigan State University
Strategies For The Production Of Cell Wall-Deconstructing Enzymes In Lignocellulosic Biomass And Their Utilization For Biofuel Production, Sang-Hyuck Park, Rebecca Garlock Ong, Mariam Sticklen
Rebecca Ong
Microbial cell wall-deconstructing enzymes are widely used in the food, wine, pulp and paper, textile, and detergent industries and will be heavily utilized by cellulosic biorefineries in the production of fuels and chemicals. Due to their ability to use freely available solar energy, genetically engineered bioenergy crops provide an attractive alternative to microbial bioreactors for the production of cell wall-deconstructing enzymes. This review article summarizes the efforts made within the last decade on the production of cell wall-deconstructing enzymes in planta for use in the deconstruction of lignocellulosic biomass. A number of strategies have been employed to increase enzyme yields …
The “Phunger Games”: Manuscript Review To Assess Graduating Chemistry Majors,
2016
Smith College
The “Phunger Games”: Manuscript Review To Assess Graduating Chemistry Majors, David J. Gorin, Elizabeth R. Jamieson, Kate Queeny, Kevin M. Shea, Carrie G. Read Spray
Chemistry: Faculty Publications
Numerous options exist to assess student performance using standardized, multiple-choice exams at the course and department levels. This paper describes the development and implementation of an alternative department-level assessment for graduating chemistry majors. The assessment detailed here evaluates students’ ability to transfer chemical knowledge from their classes to a real life application, namely the review of a scientific paper. Working in groups of three with full access to reference materials, students review a paper intentionally doctored by the faculty to contain a variety of errors. Student groups identify and correct mistakes in a paper with content spanning numerous chemistry subdisciplines. …
Imparting Amphiphobicity On Single-Crystalline Porous Materials.,
2016
Zhejiang University
Imparting Amphiphobicity On Single-Crystalline Porous Materials., Qi Sun, Hongming He, Wen-Yang Gao, Briana Aguila, Lukasz Wojtas, Zhifeng Dai, Jixue Li, Yu-Sheng Chen, Feng-Shou Xiao, Shengqian Ma
Chemistry Faculty Publications
The sophisticated control of surface wettability for target-specific applications has attracted widespread interest for use in a plethora of applications. Despite the recent advances in modification of non-porous materials, surface wettability control of porous materials, particularly single crystalline, remains undeveloped. Here we contribute a general method to impart amphiphobicity on single-crystalline porous materials as demonstrated by chemically coating the exterior of metal-organic framework (MOF) crystals with an amphiphobic surface. As amphiphobic porous materials, the resultant MOF crystals exhibit both superhydrophobicity and oleophobicity in addition to retaining high crystallinity and intact porosity. The chemical shielding effect resulting from the amphiphobicity of …
