Graduation date: 1997

The purpose of this research was to develop the pseudo-ternary phase diagrams for a model drug delivery system consisting of vitamin E (model drug) + soybean oil + surfactant + co-surfactant (anhydrous glycerol) + water. The model drug (vitamin E) was loaded in the oil phase. The effects of different surfactants (pure and mixed) on the phase diagram, especially the microemulsion region, were investigated. The influence of drug loading level on the phase diagram was also determined. The surfactants studied were Tween 20, Tween 80, Cremopher EL, and their mixtures. The size (area) of the microemulsion region of the phase diagram was found to be dependent on the type of surfactant used and the loading level of drug (vitamin E). The phenomenon of phase inversion from W/O microemulsion to O/W microemulsion was also investigated for the drug delivery system consisting of soybean oil (0% w/w Vitamin E loading or 30% w/w Vitamin E loading) + Tween 80 + anhydrous glycerol + water. The inversion of phases was detected by observing changes in the viscosity of the system.

The purpose of this research was to develop the pseudo-ternary phase diagrams for a model drug delivery system consisting of vitamin E (model drug) + soybean oil + surfactant + co-surfactant (anhydrous glycerol) + water. The model drug (vitamin E) was loaded in the oil phase. The effects of different surfactants (pure and mixed) on the phase diagram, especially the microemulsion region, were investigated. The influence of drug loading level on the phase diagram was also determined. The surfactants studied were Tween 20, Tween 80, Cremopher EL, and their mixtures. The size (area) of the microemulsion region of the phase diagram was found to be dependent on the type of surfactant used and the loading level of drug (vitamin E). The phenomenon of phase inversion from W/O microemulsion to O/W microemulsion was also investigated for the drug delivery system consisting of soybean oil (0% w/w Vitamin E loading or 30% w/w Vitamin E loading) + Tween 80 + anhydrous glycerol + water. The inversion of phases was detected by observing changes in the viscosity of the system.

Zeolites are crystalline, hydrated aluminosilicate minerals that are characterized by their ability to exchange some of their constituent cations with cations in aqueous solutions, without a major change in their crystalline structure. Clinoptilolite is the most abundant ype of zeolite and it has received extensive attention due to its favorable selectivity for mmonium and certain heavy metal cations. The aim of this study is to investigate the binary and ternary (multicomponent) ion xchange behavior of sodium form of G&ouml / rdes type clinoptilolite for ammonium,cadmium and sodium ions. For this purpose, NH4 +-Na+,Cd2+-Na+ binary systems and NH4 +-Cd2+-Na+ multicomponent system were investigated both in batch and column systems at 0.1 and 0.01 constant total normality respectively and at 250C constant temperature. As a result of binary and ternary experiments, clinoptilolite&rsquo / s affinity for both ions but greater affinity to NH4+ ion than Cd2+ ion was observed and the selectivity sequence of G&ouml / rdes clinoptilolite was determined as NH4+&gt / Cd2+&gt / Na+ in binary and multicomponent batch and column operations. Additionally, total ion exchange capacities and maximum exchange levels of G&ouml / rdes clinoptilolite for both ions were determined in batch systems whereas breakthrough capacities and column efficiencies (for three different flow rates) were determined in column systems. Finally, it was concluded that the increase of the flow rate reduced the breakthrough capacities and column efficiencies of G&ouml / rdes clinoptilolite for ammonium and cadmium ions in multicomponent column systems involving more than one cation.

Abstract The defect structure of CuMX2 (MºIn, Ga and XºS, Se, Te) was investigated. The defect concentrations were derived as a function of nonmolecularity( X) and nonstoichiometry( Y), and the carrier concentrations were calculated quantitatively using a theoretical defect model, which could be used to select the proper region of stoichiometry for device designs with specified carrier concentrations. The compensation reaction between dopants and intrinsic defects in CuMX2, compound semiconductors is quantitatively illustrated. If for a small increment of temperature the Fermi level EF is shifted by £GEF and the concentration of free majority carriers is increased by £Gn, then the ratio£Gn /£GEFis a measure of the defect-level concentration within£GEF. The electrical and optical properties of CuMX2 have been investigated using various types of electrically active intrinsic defects caused by deviations from the ideal stoichiometry of the compound. The defect complexes are formed by reactions among the impurity and native defects and/or among the native defects during crystal growth or during processing, and play a significant role in determining the characteristics and performance of devices by affecting lifetimes, degradation and breakdown etc.

In addition to their potential use at low to moderate temperatures in mobile fuel cell technologies, metal hydrides may also find application as high temperature tritium getterers in the U.S. DOE Next Generation Nuclear Plant (NGNP). We use Density Functional Theory to identify metal hydrides capable of sequestering tritium at temperatures in excess of 1000 K. First we establish the minimum level of theory required to accurately capture the thermodynamics of highly stable metal hydrides and determine that isotope effects can be neglected for material screening. Binary hydride thermodynamics are largely well established, and ternary and higher hydrides typically either do not form or decompose at lower temperatures. In this thesis we investigate anomalous systems with enhanced stability in order to identify candidates for the NGNP application beyond the binary hydrides. Methods implemented in this work are particularly useful for deriving finite temperature phase stability behavior in condensed systems. We use grand potential minimization methods to predict the interstitial Th−Zr−H phase diagram and apply high throughput, semi-automated screening methodologies to identify candidate complex transition metal hydrides (CTMHs) from a diverse library of all known, simulation ready ternary and quaternary CTMHs (102 materials) and 149 hypothetical ternary CTMHs based on existing prototype structures. Our calculations significantly expand both the thermodynamic data available for known CTMHs and the potential composition space over which previously unobserved CTMHs may be thermodynamically stable. Initial calculations indicate that the overall economic viability of the tritium sequestration system for the NGNP will largely depend on the amount of protium rather than tritium in the metal hydride gettering bed feed stream.

The E2A-PBX1 fusion gene results from the t(1;19) chromosomal translocation that is found in 25% of pre-B-cell cases of acute lymphoblastic leukemia (ALL). The resulting encoded product contains the transactivation domains of E2A, a Class I basic helix-loop-helix transcription factor, and most of PBX1. PBX1 is a major cofactor for most members of the HOX family of homeodomain proteins and is necessary for regulating the essential role that HOX proteins play in development and tissue homeostasis. We have identified an interaction between the E2A-encoded portion of E2A-PBX1 and the CREB-binding domain (KIX) of the transcriptional coactivator CBP and demonstrated a requirement for this interaction in leukemia induction. Others have shown that HOX proteins and CBP also interact directly, with resulting inhibitory effects on the DNA-binding ability of HOX proteins and on the acetylation of substrate proteins by CBP. Several publications have also identified the interaction of HOX proteins with the PBX1 portion of E2A-PBX1 and the result is a potent transcriptional activator at PBX1/HOX target sequences. In an attempt to develop a molecular model for the induction of ALL by E2A-PBX1, we hypothesize that the addition of CBP interactive peptide elements encoded by E2A to PBX1 allows E2A-PBX1 to stabilize a ternary complex involving E2A-PBX1, HOX, and CBP resulting in the deregulated expression of critical PBX1 or HOX target genes. I demonstrate using in vitro protein-protein interactions that this ternary complex involving E2A-PBX1, HOXB4 (chosen as a representative member of the HOX family), and CBP does form. This direct interaction appears to reduce transcriptional activation by E2A-PBX1/HOXB4 heterodimers from PBX1/HOX enhancer elements. I also show that this suppression of transactivation appears to involve CBP antagonism of DNA binding by E2A-PBX1/HOXB4 heterodimers. My results are consistent with the idea that E2A-PBX1 contributes to ALL induction by promoting the redistribution of CBP away from DNA sites bound by E2A-PBX1/HOXB4 heterodimers and in favour of those sites bound by E2A-PBX1 homodimers. / Thesis (Master, Pathology & Molecular Medicine) -- Queen's University, 2008-09-29 13:57:25.324

In the present study, dilute alloys in the Mg-rich corner of the Mg-Ce-In ternary system in the composition range 0 to 3% In and 0 to 1.5% Ce were synthesized. Cooling curve analysis was used to determine the liquidus points in order to construct the liquidus surface of the ternary phase diagram in the Mg corner. Energy dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS), and x-ray diffraction (XRD) techniques were used to examine phases present at the compositions studied. A thermal arrest presumed to represent a eutectic transformation was discovered at 580°C. Two new intermetallic compounds, designated tau and theta, were found. Trace silicon present in the alloys was found to concentrate in one of the intermetallic compounds. / To further investigate these compounds, an induction furnace was used to synthesize alloys containing the concentrations of Ce and In seen in electron probe micro-analysis (EPMA) examinations of these compounds. The alloys were examined using the cooling curve technique and XRD, and proved to contain the compounds already observed with some variation in dissolved indium content. In addition, differential scanning calorimetry (DSC) was used to confirm the liquidus and solidus values determined using cooling curve analysis. / A diffusion couple with terminal compositions of pure Ce and a Mg-In alloy was prepared in order to determine the equilibrium phases present in the system between these two compositions at 390°C. EPMA was used to identify the zones obtained, and confirmed the presence of several Mg-Ce compounds with 1 at% dissolved indium, as well as a ternary compound corresponding to the theta compound found in the dilute alloys. / Finally, literature values and experimental data were used to calculate a preliminary ternary phase diagram using FACTSage, in collaboration with the CTRC at Ecole Polytechnique, in order to affirm the validity of the experimentally determined values as well as to project the diagram beyond the studied composition range.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 100-105). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9947982.

Thesis (M.Sc.(Metallurgical Engineering))--University of Pretoria, 2003. / Includes bibliographical references (leaves 127-128).