In reactions of complex feeds over Pt/zeolites, resulting reactivities and selectivities cannot be deduced from pure component data alone. In order to explore competitive reactions in zeolitic media, we have chosen a binary feed model. The binary feed consists of a paraffin component (or primary species) and an aromatic component (or secondary species). Previous research has shown that the presence of aromatics can inhibit the paraffin reaction and in some cases modify the resulting product distribution. This inhibition effect, due to the presence of the aromatic cofeed, can be compared to the effect seen in reactions occurring in catalysts that have been partially deactivated due to the formation of coke. Previously, an analysis method based on Arrhenius plots was developed that, in theory, could determine if deactivation due to coke formation was a result of site suppression or pore blockage. We utilize this method, along with detailed product distribution analyses, to aid in the illumination of aromatic inhibition effects on the paraffin reactions In this dissertation, several different aspects of competitive reactions are explored. Paraffin inhibition by aromatics as a function of zeolite pore size and structure was studied by performing reactions over different types of Pt/zeolites. The effect of aromatic size on the paraffin reaction, and the effect of paraffin chain length, were explored. Additionally, experiments of paraffin reactions over deactivated catalysts were carried out and compared to the results of reactions in the presence of aromatics. Finally, a brief exploration of binary feed reactions over pure acid zeolite was performed Experimental results of the binary feed reactions over Pt/zeolites show many interesting and unexpected trends. Zeolite pore size and structure, aromatic size, and the presence of platinum on the catalyst were all found to be important factors in the extent of paraffin inhibition that occurred. Additionally, inhibition due to catalyst deactivation and paraffin-induced inhibition appear to occur by different mechanisms. The results of this research are extremely illuminating in understanding phenomena that occur during the processing of complex feeds. Applications of this work to important commercial processes are presented and discussed / acase@tulane.edu

The aim of this dissertation is to design and develop novel hydrogel material systems with controllable features such as charge, size and morphology for potential use in bio- and nanotechnology. The applications include drug delivery vehicles, templates for inorganic material synthesis, gene therapy and sensors Various types of hydrogels were prepared as neutral and charged in bulk and characterized for possible applications i.e. drug carriers for ophthalmology and absorbents for environmental applications. Several kinds of surfactant self-assembly environments such as water-in-oil and oil-in-water microemulsion systems were utilized for nanohydrogel syntheses with tunable morphology. The surfactants used in this research were L-alpha-phosphotidylcholine (lecithin), bis(2-ethylhexyl) sodium sulfosuccinate (AOT), and sodium dodecyl sulfate (SDS) A neutral hydrogel from HEMA has been prepared in the form of disk and its ophthalmologic application as drug carriers were explored. Anionic hydrogels, synthesized from 2-Acrylamido-2-methyl-1-propansulfonic acid (AMPS) have been investigated as templates for in situ metal nanoparticle syntheses utilizing their ion exchange ability. Other pH sensitive cationic hydrogels from (3-Acrylamidopropyl)-trimethylammonium chloride (APTMCl) have been synthesized as bulk and characterized. In situ rheological network formations of cationic hydrogels were also investigated. The determination of mechanical and viscoelastic behavior of hydrogels is very important for their design in their post usage. In the light of rheological investigations, nanosize cationic hydrogels were synthesized and shown to bind DNA strongly for possible gene therapy applications. Additionally, organic-inorganic composites of cationic nanohydrogels were prepared by encapsulating ferrite particles inside nanohydrogels, and by utilizing ceramic precursors before and during the polymerization The design of novel systems with predictable features was investigated for smart material synthesis. For this purpose, novel thermoresponsive nanoparticles with well-defined architectures such as controllable shell thickness and core size, and adjustable hydrophilic/hydrophobic balance have been prepared from acrylonitrile (AN) and N-isopropylacrylamide (NIPAM). The core material (AN) was further manipulated and its chemical structure was converted by amidoximation reaction from hydropobic to hydrophilic one. The induced new functionality has proven to be very useful for the absorption and the release of a hydrophilic model drug, propranolol, in response to temperature stimulus / acase@tulane.edu

acase@tulane.edu

While one of the most obvious behavioral asymmetries in humans is hand preference, the relationship between degree of handedness, size of the hand representation, and degree of functional activation in sensorimotor cortex between right (RH) and left handers (LH) has not been well studied. In Experiment 1, using volumetric MRI, the surface area (cm2) of the anterior bank of the central sulcus (MI), motor knob (MK), and the posterior bank of the central sulcus (SI) was measured in 20 RH and 20 LH men and women matched for age and education. A significant Sex x Hemisphere x Writing Hand interaction was detected for MI, MK, and SI (all p < 0.05). In RHs, men had a leftward asymmetry while women showed an unexpected rightward asymmetry. For LHs, men had a rightward asymmetry while women had a leftward asymmetry. There was no significant relationship between degree of handedness and surface area of MI, MK, and SI In Experiments 2 and 3, using a different sample of subjects, the surface area of MI, MK, and SI was measured in 9 RH and 8 LH males. Using fMRI, activation was measured during simple motor (air piano), active somatosensory (finger tapping), and passive somatosensory tasks (von Frey). There was a significant main effect of Hemisphere on Surface Area for MI and SI (all p < 0.05), but not for MK (p > 0.05) with MI and SI larger in the right hemisphere across handedness groups. For all tasks, there was a significant main effect of Function on Hand Used for RH and LH (all p < 0.01) where the largest activation was in the contralateral hemisphere regardless of hand used. There was a significant 2-way Writing Hand by Function interaction (all p < 0.01) for air piano and finger tapping where the largest activation was in the contralateral hemisphere across handedness groups, but in this contralateral hemisphere, LH had more activation than RH. There were significant findings relating degree of handedness, surface area of SI, and degree of activation for finger tapping and von Frey which suggested that as degree of handedness decreased, and surface area of SI increased, degree of functional activation increased / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu