Nanoparticle-Based Drug-Delivery Systems Studied By Second Harmonic Generation, 2017 Louisiana State University and Agricultural and Mechanical College
Nanoparticle-Based Drug-Delivery Systems Studied By Second Harmonic Generation, Raju Ram Kumal
LSU Doctoral Dissertations
Second harmonic generation (SHG) is used to study different types of colloidal nanoparticle drug-delivery systems. The surface charge density, electrostatic surface potentials, and ion adsorptions of 50 nm colloidal gold nanoparticle samples coated with mercaptosuccinic acid are determined using SHG measurements under varying NaCl and MgCl2 concentrations in water. Numerical solutions to the spherical Poisson-Boltzmann equation are fit to the SHG results to account for the nanoparticle surface curvature and ion adsorption to the Stern layer interface, showing excellent agreement with electrophoretic mobility measurements. In another study, nanoparticles of gold, silver and polystyrene are functionalized with microRNA using a ...
Applying Machine Learning To Computational Chemistry: Can We Predict Molecular Properties Faster Without Compromising Accuracy?, Hanjing Xu, Pradeep Gurunathan, Lyudmila Slipchenko
The Summer Undergraduate Research Fellowship (SURF) Symposium
Non-covalent interactions are crucial in analyzing protein folding and structure, function of DNA and RNA, structures of molecular crystals and aggregates, and many other processes in the fields of biology and chemistry. However, it is time and resource consuming to calculate such interactions using quantum-mechanical formulations. Our group has proposed previously that the effective fragment potential (EFP) method could serve as an efficient alternative to solve this problem. However, one of the computational bottlenecks of the EFP method is obtaining parameters for each molecule/fragment in the system, before the actual EFP simulations can be carried out. Here we present ...
Temperature-Dependent Exciton Dynamics Of Superacid Treatment In Monolayers Of The Metal Dichalcogenide Mos2, Mingwei Zhou, Long Yuan, Jordan Snaider, Libai Huang
The Summer Undergraduate Research Fellowship (SURF) Symposium
To improve optoelectronic semiconductor materials, one of the most efficient research areas is the two-dimensional (2D) transition-metal dichalocogenides (TMDCs). It has been shown that organic nonoxidizing superacid bis(trifluoromethane)sulfonamide (TFSI) treatment of molybdenum disulfide (MoS2) monolayer could uniformly enhance its photoluminescence by more than two orders of magnitude and also extend the lifetime of excitons. This could greatly improve the efficiency of the solar energy usage, but the mechanism behind it has not been fully understood. Extreme low temperatures (approximately 7K), which slow the surface exciton mobility, were applied to investigate the changes of treated MoS2 monolayer ...
Synthesis And Catalytic Evaluation Of Novel C-Alpha-Methyl-Beta-Proline Analogues, And Concise Synthetic Approach To Nh-Fmoc-S-Trityl-C-Alpha-Methyl Cysteine, 2017 University of Southern Mississippi
Synthesis And Catalytic Evaluation Of Novel C-Alpha-Methyl-Beta-Proline Analogues, And Concise Synthetic Approach To Nh-Fmoc-S-Trityl-C-Alpha-Methyl Cysteine, Hari Kiran Kotapati
In the field of chemistry there is a growing demand for small molecule organocatalysts such as amino acids, more specifically proline and its analogues, which could catalyze various key chemical reactions in the synthesis of several biologically important molecules. Even though natural proline is reported to catalyze various chemical reactions, its use as organocatalyst is limited mainly due to the solubility issues in the reaction media and high catalyst loadings, which is not very ideal for bulk scale manufacturing. To address these limitations we planned to develop unnatural analogues of proline that could catalyze the reactions with lower catalyst loadings ...
Exploring Two Approximate Coupling Models In Exciton Transport, 2017 DePaul University
Exploring Two Approximate Coupling Models In Exciton Transport, James Irish-Ryan
Point dipole and line dipole coupling approximations are two methods for approximating the transition dipole coupling between two conjugated organic molecules. Transition dipole couplings are an important factor in determining energy transfer between two non-covalently-bonded molecules. Transition dipole couplings were mathematically calculated by two methods, applying the point dipole and line dipole approximations. The calculations were implemented using Octave, an open source computer programming language. Using this tool, software was created to efficiently analyze the differences between transition dipoles calculated using the two methods, for a variety of relative orientations of two model conjugated organic molecules. Custom-built software was created ...
Mixed Quantum/Classical Theory (Mqct) For Rotationally And Vibrationally Inelastic Scattering And Its Application To The Molecules Of Astrochemical Importance, Alexander Semenov
Dissertations (2009 -)
This thesis presents developments and applications of the mixed quantum/classical theory (MQCT) for inelastic scattering. In this approach, translational motion of collision partners is treated classically, while the internal degrees of freedom – rotational and/or vibrational motion – are treated quantum mechanically. Within this framework calculations of rotationally inelastic cross sections are carried out in a broad range of collision energies and results are compared against the exact full quantum data for several real systems. For CO +He, N2 + Na and H2 + He the agreement is excellent through six orders of magnitude range of cross sections values and for energies ...
Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, 2017 Marquette University
Functional And Structural Studies Of Cytochromes P450 By Resonance Raman Spectroscopy, Yilin Liu
Dissertations (2009 -)
Cytochrome P450 is a broad class of heme monooxygenase enzymes which catalyze various oxidative transformations. There are two main kinds of mammalian P450s: steroidogenic and drug metabolizing P450s. The first project involves a steroidogenic P450, CYP17A1, occupying a central role in the biosynthesis of steroid hormones. It catalyzes hydroxylation reaction on pregnenolone and progesterone, generating 17OH-pregnenolone and 17OH-progesterone, presumably utilizing a “Compound I” species. However, these hydroxylated products can be further processed in a second oxidative cycle to cleave the C17–C20 bond to form dehydroepiandrosterone or androstenedione, respectively, a crucial step in androgen production. Interestingly, it is well known ...
Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, 2017 Carnegie Mellon University
Comparative Study Of The Tribological And Oxidative Properties Of Alpdmn Quasicrystals And Their Cubic Approximants, Chris Mancinelli, Jeff S. Ko, Cynthia J. Jenks, Patricia A. Thiel, Amy R. Ross, Thomas A. Lograsso, Andrew J. Gellman
Thomas A. Lograsso
An experimental comparison has been made between the properties of the surfaces of an Al70Pd21Mn9quasicrystal and its Al48Pd42Mn10 approximant. The Al70Pd21Mn9 sample was a single grain icosahedral quasicrystal cut to expose its five-fold symmetric (000001) surface. The approximant was polycrystalline β-phase Al48Pd42Mn10, which has a CsCl-type cubic structure. Surfaces of both were prepared under ultra-high vacuum (UHV) conditions and then used for comparative measurements of their frictional properties and oxidation rates. Both materials are oxidized by reaction with O ...
Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, 2017 The University of Western Ontario
Evolution Of Cu2o Morphology During Copper Corrosion In The Presence Of Gamma-Radiation, Arielle M. Jean
Electronic Thesis and Dissertation Repository
In this work, experiments were carried out in order to develop a mechanistic understanding of the corrosion of copper metal in limited water volumes under gamma-radiation. When exposed to gamma-radiation, water decomposes into chemically reactive oxidizing and reducing species. Under a continuous radiation flux, the concentrations of the radiolytically produced oxidants eventually reach a pseudo-steady state that can influence the corrosion kinetics of metallic surfaces.
The evolution of the surface morphology during water droplet corrosion of copper in the presence of gamma-radiation was investigated as a function of irradiation time and pH. The oxide growth kinetics were studied by measuring ...
The Mathematical Structure Of Arrangement Channel Quantum Mechanics, 2017 Iowa State University
The Mathematical Structure Of Arrangement Channel Quantum Mechanics, James W. Evans
James W. Evans
A non-Hermitian matrix Hamiltonian H appears in the wavefunction form of a variety of many-body scattering theories. This operator acts on an arrangement channel Banach or Hilbert space 1(;' = Ell ncr where ,r is the N-particle Hilbert space and a are certain arrangement channels. Various aspects of the spectral and semigroup theory for H are considered. The normalizable and weak (wavelike) eigenvectors ofH are naturally characterized as either physical or spurious. Typically H is scalar spectral and "equivalent" to H on an H-invariant subspace of physical solutions. If the eigenvectors form a basis, by constructing a suitable biorthogonal system, we ...
Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, 2017 Iowa State University
Heterogeneous Multicatalytic System For Single-Pot Oxidation And C–C Coupling Reaction Sequences, Nicholas C. Nelson, Umesh Chaudhary, Kapil Kandel, Igor I. Slowing
Igor I. Slowing
A system comprising two catalysts supported on mesoporous silica nanoparticles (MSNs) was employed to perform a sequence of two reactions in a single pot. Palladium nanoparticles catalyzed the oxidation of furfuryl alcohol with molecular oxygen at atmospheric pressure. The oxidation product, furfural, was then reacted with acetone via an aldol condensation catalyzed by amines supported on MSNs. Each reaction was first tested individually to establish optimal conditions. Both catalysts were then introduced into the same reactor under the proven conditions, and the entire reaction sequence was performed giving the desired product with high selectivity. The overall yield of the reaction ...
Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, 2017 Iowa State University
Supported Iron Nanoparticles For The Hydrodeoxygenation Of Microalgal Oil To Green Diesel, Kapil Kandel, James W. Anderegg, Nicholas C. Nelson, Umesh Chaudhary, Igor I. Slowing
Igor I. Slowing
Iron nanoparticles supported on mesoporous silica nanoparticles (Fe-MSN) catalyze the hydrotreatment of fatty acids with high selectivity for hydrodeoxygenation over decarbonylation and hydrocracking. The catalysis is likely to involve a reverse Mars–Van Krevelen mechanism, in which the surface of iron is partially oxidized by the carboxylic groups of the substrate during the reaction. The strength of the metal–oxygen bonds that are formed affects the residence time of the reactants facilitating the successive conversion of carboxyl first into carbonyl and then into alcohol intermediates, thus dictating the selectivity of the process. The selectivity is also affected by the pretreatment ...
Substrate Inhibition In The Heterogeneous Catalyzed Aldol Condensation: A Mechanistic Study Of Supported Organocatalysts, Kapil Kandel, Stacey Marie Althaus, Chorthip Peeraphatdit, Takeshi Kobayashi, Brian G. Trewyn, Marek Pruski, Igor I. Slowing
Igor I. Slowing
In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of ...
Exocytosis Of Mesoporous Silica Nanoparticles From Mammalian Cells: From Asymmetric Cell-To-Cell Transfer To Protein Harvesting, Igor I. Slowing, Juan L. Vivero-Escoto, Yannan Zhao, Kapil Kandel, Chorthip Peeraphatdit, Brian G. Trewyn, Victor S.Y. Lin
Igor I. Slowing
The exocytosis of mesoporous silica nanoparticles (MSNs) from mammalian cells is demonstrated for the first time. The differences in the degree of exocytosis of MSNs between healthy and cancer cells are shown to be responsible for the asymmetric transfer of the particles between both cell types. The exocytosis of highly adsorbent magnetic MSNs proves to be useful as a means for harvesting biomolecules from living cells.
Conformational Studies Of Gram-Negative Bacterial Quorum Sensing 3-Oxo N-Acyl Homoserine Lactone Molecules, 2017 Institute of Technology Tallaght
Conformational Studies Of Gram-Negative Bacterial Quorum Sensing 3-Oxo N-Acyl Homoserine Lactone Molecules, Darren Crowe, Alan Nicholson, Adrienne Fleming, Ed Carey, Goar Sanchez-Sanz, Fintan Kelleher
In their 1H NMR spectra in CDCl3 3-oxo-N-acyl homoserine lactones (OHLs) show significant downfield chemical shifts of the amide N-H proton when compared to the parent N-acyl homoserine lactones (AHLs). NMR spectroscopic and DFT calculation studies have shown that this is most likely due to the presence of a stabilising intramolecular H-bond from the N-H to the 3-oxo group. The 1H NMR spectra also show evidence for the enol tautomers and that the amount of enol present for a range of OHLs is 4.1-4.5% in CDCl3 and 6.5-7.2% in ...
The Investigation And Characterization Of The Reaction Of 2-Methylfuran And 2-Methyl-3-Buten-2-Ol With O(3p) And The Photodissociation Of Xylyl Bromide Isomers, Yasmin Fathi
This thesis has studied the oxidation behavior of different biofuels or additives, 2-methyl-3-buten-2-ol and 2-methylfuran, in combustion experiments at the Chemical Dynamics Beamline held at the Advanced Light Source of the Lawrence Berkley National Laboratory. The oxidation of these fuels were initiated through O(3P) and the combustion experiments were analyzed using a multiplexed chemical kinetics photoionization mass spectrometer with tunable synchrotron radiation. Products of the different reactions were identified using kinetic profiles and further characterized using the photoionization spectra. The amount of each species was calculated using branching fractions.
Additionally, the unimolecular dissociation of the xylyl bromide isomers ...
Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, 2017 Clark Atlanta University
Electronic And Magnetic Properties Of Carbon-Based And Boron-Based Nano Materials, Rosi Gunasinghe
Electronic Theses & Dissertations Collection for Atlanta University & Clark Atlanta University
The structural and electronic properties of covalently and non-covalently functionalized graphene are investigated by means of first-principles density-functional-theory. The electronic characteristics of non-covalently functionalized graphene by a planar covalent organic framework (COF) are investigated. The aromatic central molecule of the COF acts as an electron donor while the linker of the COF acts as an electron acceptor. The concerted interaction of donor acceptor promotes the formation of planar COF networks on graphene. The distinctive electronic properties of covalently functionalized fluorinated epitaxial graphene are attributed to the polar covalent C–F bond. The partial ionic character of the C–F bond ...
Adsorption And Wetting In Model Mesoporous Silicas And In Complex Metal Oxide Catalysts, 2017 Seton Hall University
Adsorption And Wetting In Model Mesoporous Silicas And In Complex Metal Oxide Catalysts, Karthik Jayaraman
Seton Hall University Dissertations and Theses (ETDs)
The surface of most metal oxides is covered by hydroxyl groups which influence many surface phenomena such as adsorption and wetting, catalysis and surface reactions. Surface chemistry of silica is a subject of exhaustive studies owing to a wide variety of practical applications of silica. In Chapter 1, a brief review of classification, synthesis and characterization of silica is provided. The hydroxylation of silica surface i.e the number of hydroxyl (-OH) groups on the surface is of utmost importance for its practical applications. In Chapter 2, a brief introduction to surface hydration of silica is provided followed by the ...
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, 2017 University of New Mexico
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, Tzucheng Wu
Physics & Astronomy ETDs
This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions ...
Graphene Nanoribbons And Their Polymeric Nanocomposites: Controlled Synthesis, Characterization And Applications, 2017 Pittsburg State University
Graphene Nanoribbons And Their Polymeric Nanocomposites: Controlled Synthesis, Characterization And Applications, Nada M. Aljehany
Electronic Thesis Collection
Carbon based materials are very promising as electrode materials energy generation and storage devices. They have been used for fuel cells, supercapacitors and solar cells. Among the carbon-based materials, graphene is very attractive due to its unique properties such as high electrical conductivity, good mechanical flexibility, large theoretical surface area (2630 m2/g), and high thermal and chemical stability. These unique properties make them very suitable for energy storage applications particularly for supercapacitors. The performance of the graphene as energy storage material could be further improved by growing them in nanoribbon form by unzipping carbon nanotubes. In this thesis ...