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Full-Text Articles in Physical Sciences and Mathematics

A Study Of The Self-Assembly Of Water-Soluble Porphyrins In Aqueous Solution, Javoris Hollingsworth Jan 2009

A Study Of The Self-Assembly Of Water-Soluble Porphyrins In Aqueous Solution, Javoris Hollingsworth

LSU Master's Theses

In nature, self-assembly processes of biologically active organic molecules often occur, resulting in formation of dimers and higher oligomers of various and sometimes complex structures. This natural occurrence of self-organization has been the subject of research, with the aim of understanding and possibly modulating the aggregation behavior of biological molecules. The meso-tetrakis(4-phosphonatophenyl) porphyrin, H2TPPP was synthesized, purified, and characterized. Its self-assembly was studied in aqueous solutions as a function of pH and time. The variations on the λmax and shape of the Soret band of this porphyrin in the absorption spectra when altering the pH indicated the pH dependency in …


Characterization And Transitions Of Asphalt Cement Composite Materials, Brent Harper Sellers Jan 2009

Characterization And Transitions Of Asphalt Cement Composite Materials, Brent Harper Sellers

LSU Master's Theses

Blends of a PG 64-22 asphalt with a range of load levels (0.2 — 20 wt %) of Sasobit® wax and a single loading of 2 wt % Elvaloy AM® were prepared and characterized. Sasobit® wax is a high molecular weight paraffinic wax produced commercially through the Fischer-Tropsch process. Elvaloy AM® is a reactive elastic terpolymer, comprised of ethylene, butyl acrylate and glycidyl methacrylate monomeric units. The blends were analyzed by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), x-ray diffraction, epifluorescence microscopy, scanning laser confocal microscopy, and dynamic shear rheology. Sasobit (1 wt %) composite material showed little difference …


Capillary Electrophoretic Separations Of Enzyme Inhibitors With Activity-Based Detection, Xiaoyan Yan Jan 2009

Capillary Electrophoretic Separations Of Enzyme Inhibitors With Activity-Based Detection, Xiaoyan Yan

LSU Master's Theses

A technique for separating and detecting enzyme inhibitors was developed using capillary electrophoresis with an enzyme microreactor. The on-column enzyme microreactor was constructed using one or two NdFeB magnets in two configurations to immobilize alkaline phosphatase-coated superparamagnetic beads with diameters of 2.8 µm inside a capillary before the detection window. Enzyme inhibition assays were performed by injecting a plug of inhibitor into a capillary filled with an alkaline phosphatase substrate, AttoPhos. Product generated in the enzyme microreactor was detected by laser-induced fluorescence. Inhibitor zones electrophoresed through the capillary, passed through the enzyme microreactor, and were observed as negative peaks due …


Substituted Bis(Beta-Diketones) For Molecular Squares, Jace Sandifer Jan 2009

Substituted Bis(Beta-Diketones) For Molecular Squares, Jace Sandifer

LSU Master's Theses

Our group has been synthesizing porous supramolecular metal-organic molecules using multidentate β-diketones as ligands. For example, m-phenylenebis(acetylacetone) (m-pbaH2, 1) and m-phenylenebis(dipropionylmethane) (m-pbprH2, 2) were readily converted to the molecular squares Cu4(m-pba)4 (6) and Cu4(m-pbpr)4 (7), which bind guests such as 4,4’-bpy and C60.1 However, 6 and 7 are only soluble in a few solvents, limiting their use in practical applications. It is therefore necessary to derivatize the ligand with different functional groups in order to improve solubility and adjust host-guest properties. Simple alkoxy derivatives should prove useful in testing this idea as they would be relatively chemically inert and should …


A Novel Synthesis And Characterization Of Fluorescein Isothiocyanate Labeled Poly(Styrenesulfonate Sodium Salt), Xiaowei Tong Jan 2009

A Novel Synthesis And Characterization Of Fluorescein Isothiocyanate Labeled Poly(Styrenesulfonate Sodium Salt), Xiaowei Tong

LSU Master's Theses

The diffusion of polyelectrolytes in low-salt or salt-free aqueous solutions is a controversial question. It has been intensively discussed since it was discovered in 1978. Most previous experimental data were obtained from dynamic light scattering (DLS), whose precision, however, was reduced by stringent sample preparation and weak scattering of polyelectrolyte in low-salt solution. For the most commonly studied polyelectrolyte, poly(styrenesulfonate sodium salt) (NaPSS), the harsh polymerization condition and the manufacturing procedure lead to hydrophobic defects and aggregations, which also block a correct insight about the diffusion of polyelectrolyte. In contrast to DLS, fluorescence photobleaching recovery (FPR) directly looks on the …