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Articles 1 - 11 of 11

Full-Text Articles in Physical Sciences and Mathematics

Inclusion Of Customized Quantum Dots Into Laponite Based Nanocomposites, Jennifer Rae Eliseo Jun 2005

Inclusion Of Customized Quantum Dots Into Laponite Based Nanocomposites, Jennifer Rae Eliseo

Honors Theses

Quantum dot (QD) semiconductor nanocrystals offer unique electronic, magnetic, and optical properties, that can be used in advanced materials applications including optoelectronics, catalysis, sensing, and quantum computing. Tailoring of quantum dot surface coatings allows for control of self-assembly and facile inclusion into various host matrices. Querner and colleges have provided a novel synthetic route to graft aniline tetramer units onto quantum dots via a disulfide bridge. A key goal of our work has been the optimization of this synthesis for inclusion of functionalized QDs within Laponite/polyaniline nanoscaffolds. Uv/visible and fluorescence spectroscopy were used to study frequency resonance energy transfer within …


The Effects Of Water On The Physical Properties Of Silica Aerogels, Shira G. Mandel Jun 2005

The Effects Of Water On The Physical Properties Of Silica Aerogels, Shira G. Mandel

Honors Theses

The research found in this report focuses on varying the amount of water used in the fabrication of silica aerogels and characterizing the effect this has on their physical properties, such as density, thermal conductivity and transmittance. So far, the aerogels made with the "original" recipe have produced average density of 0.09 g/cm3 and thermal conductivity of 0.04 W/mK; these properties are not significantly altered as the amount of water used is increased or decreased. However, there is an observable trend in transmittance; as more water is added to the "standard" recipe, the resulting monoliths become more transparent and less …


The Design, Synthesis And Analysis Of High-Affinity Peptide-Peptoid Hybrid Ligands That Bind Evh1 Domains & The Synthesis Of 1-Substituted M-Terphenyls That Seve As N^C^C And O^C^C Ligands For Use In Cyclometallated Platinum Complexes, Eric J. Dimise Jun 2005

The Design, Synthesis And Analysis Of High-Affinity Peptide-Peptoid Hybrid Ligands That Bind Evh1 Domains & The Synthesis Of 1-Substituted M-Terphenyls That Seve As N^C^C And O^C^C Ligands For Use In Cyclometallated Platinum Complexes, Eric J. Dimise

Honors Theses

Protein-ligand interactions are often at the center of cellular regulatory processes. The Enabled/ vasodilator Stimulated Phosphoprotein Homology 1 (EVH1) domain of the Enabled/ Vasodilator Stimulated Phosphoprotein (Ena/VASP) protein family has been linked to the regulation of the actin cytoskeleton through multiple protein-protein interactions via the recognition of polyproline amino acid sequences. Here, we examine the structural and physicochemical features of the EVH1 domain in an effort to design high affinity peptide-peptoid hybrid ligands that compete with EVH1's natural binding partners. & The unique photophysical properties of aryl, tridentate complexes of platinum have recently led to a surge in ligand design …


Guest-Host Chemistry Of P-Sulfonatocalix[6]Arene And Nizatidine, Galia Debelouchina May 2005

Guest-Host Chemistry Of P-Sulfonatocalix[6]Arene And Nizatidine, Galia Debelouchina

Honors Theses

This work investigates the guest-host chemistry in water of p-sulfonatocalix[6]arene and a number of guests related to the amino acids arginine and lysine. Two questions are particularly important: what are the interactions that drive guest-host binding and what is the role of the solvent. The answers to these questions are investigated with isothermal titration calorimetry (lTC), which gives K, ?H, and ?S, and pressure perturbation calorimetry (PPC), which allows the calculation of the thermal coefficient of expansion ? and relating it to a molecule's structure-breaking or structure-making properties. The ITC data suggests that hydrogen bonding and charge-charge interactions are the …


The Synthesis Of Biomimetic Tungsten And Molybdenum Complexes, John Sterling Cole Iii May 2005

The Synthesis Of Biomimetic Tungsten And Molybdenum Complexes, John Sterling Cole Iii

Honors Theses

The synthesis of novel biomimetic molybdenum and tungsten compounds that are potential model complexes for molybdenum and tungsten oxidase enzymes is being pursued. Model complexes such as these provide a better understanding of the basic chemistry of a metal center in an environment similar to that found in particular enzyme active sites. This understanding provides a good starting point for biologists or biochemists studying those biological systems. The first target complex will incorporate a tetradentate-S4 ligand (L) that features two biphenyl-S2 fragments joined by a propyl linker. The second target complex will incorporate a bidentate ligand (L') with a singly …


An Investigation Of Modified Superconductivity Through Structural Alteration Of Mgcni3 And Mgb2, Nathan L. Henderson Apr 2005

An Investigation Of Modified Superconductivity Through Structural Alteration Of Mgcni3 And Mgb2, Nathan L. Henderson

Honors Theses

No abstract provided.


Photochemical Generation Of 2-Methoxy-2methylpropylidene And Its Rearrangement Pathways, Stanislav Presolski Jan 2005

Photochemical Generation Of 2-Methoxy-2methylpropylidene And Its Rearrangement Pathways, Stanislav Presolski

Honors Theses

2-methoxy-2-methylpropylidene was photochemically generated from a non-nitrogenous precursor, 1a,9b-Dihydro-IH-cyclopropa[1]phenanthrene-l-etbane 2-methoxy-2-methyl, available in two steps from phenanthrene. Two competing rearrangement pathways were observed for the p-methoxy carbene, 1,2-methyl shift and C-H insertion, which had varying weights depending on the solvent used. Nevertheless, the C-H insertion was always predominant, contrary to the current understanding of B-substituted carbenes, which apparently needs revision. An attempt was also made to measure by LFP the rate constant of rearrangement and lifetime of the stabilized l-chloro-2-methoxy-2-metbylpropylidene.


Analytical Tools For Studying Phosphorus And Nitrogen Lake Nutrient Dynamics And Their Application To The Field, Ivan Mihajlov Jan 2005

Analytical Tools For Studying Phosphorus And Nitrogen Lake Nutrient Dynamics And Their Application To The Field, Ivan Mihajlov

Honors Theses

In order to evaluate the causes and conditions that lead to cyanobacteria blooms in northern temperate lakes, studies of nutrients such as total phosphorus, total nitrogen, phosphate, and nitrate are necessary. Sensitive, environmentally friendly and cost-effective techniques were developed to detect ppb-level nitrates and phosphates in the lake water. Phosphate was analyzed by luminol chemiluminescence, while the quantification of nitrate was performed by capillary electrophoresis (CE) using indirect UV detection, with a background electrolyte consisting of pyromellitic acid, hexamethonium hydroxide and triethanolamine. Sample injection methods for the CE were optimized for the analysis in Belgrade Lakes, Maine. Vertical profiles of …


Investigation Of Iron (Iii) Desferrioxamine B Oxalate Ligand Exchange By Uv-Vis Spectroscopy: The Next Step In Developing A Quantitative Analytical Method For Measuring Bioavailable Iron In Marine Ecosystems, Ken L. Pitter Jan 2005

Investigation Of Iron (Iii) Desferrioxamine B Oxalate Ligand Exchange By Uv-Vis Spectroscopy: The Next Step In Developing A Quantitative Analytical Method For Measuring Bioavailable Iron In Marine Ecosystems, Ken L. Pitter

Honors Theses

To date there are no analytical techniques designed to exclusively measure bioavailable iron in marine environments. The goal of this research is to develop such a technique by isolating the bioavailable iron using the terrestrial siderophore desferrioxamine B (DFB). This project contained many challenging aspects, but the specific goal of this study was to develop a robust analytical technique for quantification of Fe(III)-DFB complexes at nanomolar concentrations. Past work showed that oxalate (Ox) promotes photodissociation of Fe(III)-DFB to Fe(Il), and we are specifically interested in the mechanism of this process. A model was developed using known thermodynamic constants for Fe(III)-DFB …


The Synthesis And Characterization Of Bicyclooxacalixarenes, Kevin J. Selby Jan 2005

The Synthesis And Characterization Of Bicyclooxacalixarenes, Kevin J. Selby

Honors Theses

Bicyclooxacalixarenes were synthesized in high yield via a selective, room temperature Sn Ar reaction of phluoroglucinol with 2,6-dichloropyridines. Functionality on the 2,6-dichloropyridioe was varied by changing the electron-withdrawing groups in the 3 and 5 positions (using chlorine, nitro groups, and cyano groups) and the side-chains in the 4-position (using ethyl, butyl, phenyl and ρ-tolyl groups). The resulting cage-like molecules were studied by X-ray crystallography and tested for metal complexation.


An Analysis Of The Effect Of Carbon Dioxide On The Decay Rates Of Superoxide, Michael Jay Walsh Jan 2005

An Analysis Of The Effect Of Carbon Dioxide On The Decay Rates Of Superoxide, Michael Jay Walsh

Honors Theses

The radical dioxygen anion, superoxide has been shown to react with carbon dioxide in nonprotic and aqueous systems. Indirect evidence suggests that superoxide also reacts with carbon dioxide and carbonate species dissolved in water. This study involved conducting experiments to determine the decay rate of superoxide in the presence of carbon dioxide and carbonate species. Experiments were conducted by sparging an alkaline bicarbonate buffer with carbon dioxide and measuring the decay rate of superoxide added to the solution. Although the specific reaction mechanism and rates have not been determined first order superoxide decay rates as high as 3.8x10-2s-1 were obtained …