The murine <i>lpr</i> gene encodes for an aberrant form of Fas (CD95), a molecule involved in apoptosis. The mouse <i>gld</i> gene leads to the expression of a defective Fasligand. Mice homozygous for <i>lpr</i> or <i>gld</i> mutations develop severe lymphoproliferative and autoimmune disease characterized by the accumulation of unique CD4⁻CD8⁻ (double-negative, DN) T cells. Because of these poor functions in vitro, the nature and significance of DN T cells in the autoimmune disease process is not clear. In the current study we found that <i>lpr</i> DN T cells could mediate spontaneous lysis of certain tumor cells as well as mediate redirected lysis of various tumor targets when stimulated through the CD3/αβTCR complex and certain adhesion molecules, such as, CD44 and gp90^MEL-14. The DN T cells constitutively transcribed perform, TNF-α and IFN-γ genes. Unlike the DN T cells from <i>lpr</i> mice, similar cells from <i>gld</i> mice failed to exhibit spontaneous cytotoxicity despite expression of similar levels of cytokines and adhesion molecules. Furthermore, lpr DN T cells could mediate redirected lysis of Fas⁺ but not Fas⁻ target cells. Together, these studies suggested that lysis of target cells by DN T cells was dependent on the interaction between Fas and Fas-ligand. The fact that <i>lpr</i> DN T cells can be activated via CD44 and gp-90^MEL-14 suggested that these T cells may be able to mediate lysis of endothelial cells which bear the ligand for these adhesion molecules. Further studies revealed that the <i>lpr</i> DN T cells could mediate spontaneous lysis of endothelial cells and that CD44-hyaluronate interactions were important for endothelial cell lysis. Thus, interactions between DN T cells and endothelial cells <i>in vivo</i> may trigger an inflammatory response and contribute to the vasculitis seen in <i>lpr</i> and <i>gld</i> mice. We also addressed the hypothesis that acquired immunodeficiency syndrome (AIDS) may be a consequence of destabilization of the idiotypic network. These studies demonstrated that auto- or allo-immunizations involving recognition of class II MHC antigens can trigger an anti-HIV response and such possibilities should be taken into consideration while delineating the pathogenesis of AIDS. / Ph. D.

The crystal structures of zircon, scheelite, and monazite are very closely related. All three have chains of alternating polyhedra and planes of closest packed or pseudo-closest packed cations. Using these similarities the unit cells of these structures can be placed in analogous orientations. This in turn leads to a better understanding of the geometrical aspects of the reconstructive phase transformations that occur among the structure types as functions of temperature and pressure. In essence the phase transformations require the cation planes of one structure to the cation planes of another. Phase transformations also occur via compositional pathways. Crystal structure parameters were modeled for compounds with the zircon, scheelite and monazite structure types using multiple regression techniques. Data consisted of structure refinements of 26 zircon-, 13 scheelite-, and 13 monazite-type compounds. These compounds include but are not limited to the lanthanide vanadates and phosphates, the alkali earth molybdates and tungstates, and KTcO₄. The structural parameters studied included bond lengths, bond angles, polyhedral volumes, unit cell edge lengths, tetrahedral quadratic elongations and atomic coordinates of individual atoms; they were modeled as a function of the Shannon radii of the cations and the product of the M and T cation charges. Correlation coefficients for these regressions exceeded 0.9 for nearly all parameters studied except for the y coordinate of M, the z coordinate of O1, and T-O1-M2 angle of the monazite compounds. / Master of Science

The Digital European Cordless Telecommunications (DECT) standard defines a high-performance digital communications system for two-way transfer of speech and data information. This thesis is concerned with the development of a frequency hopping Spread spectrum transceiver based on the DECT radio frequency (RF) front end, and fully compliant with FCC Part 15 rules for transmissions in the 902-928 MHz ISM band. A theoretical design of a slow frequency hopper (SFH) based on an existing DECT RF front end and a custom-designed system controller was developed. An innovative FH synchronization technique that eliminates the need for a separate FH tracking loop and can be implemented completely at baseband was designed. The practicality of the design was verified through extensive simulations. The SFH design was then implemented in prototype hardware using a digital signal processor acting as the system controller and using the DECT RF front end. Results show that the existing DECT physical layer can be successfully modified for spread spectrum transmissions in the ISM band fully compliant with FCC regulations. / Master of Science

I am proposing the construction of a monumentally-scaled building nested in the waters of Venice's Bacino San Marco adjacent to the island of San Giorgio Maggiore. Programmatically, the building contains a theater, exhibition space, cafes, and a hotel/administration block. Typologically, it is a piazza. By way of an appropriate introduction, I can offer a brief discussion of the building in terms of its character and its contributions / Master of Architecture

This systematic study recognizes 15 species of the genus Mallos Pickard-Cambridge and three species of the genus Mexitilia Lehtinen. Three species of Mallos and one species of Mexitilia are newly described. Two species are placed in synonymy and two species are transferred to Mallos. The males of two Mallos species are described for the first time. A cladistic analysis based on 22 morphological produced a cladogram that supports the monophyly of Mallos and the validity of Mexitilia. For five species of Mallos and one species of Mexitilia mitochondrial and nuclear DNA sequences were analyzed by restriction digest. The seventeen resulting restriction sites produced a cladogram that agreed with the one based on the morphology of these six species. When morphological and molecular characters were combined they produced a single tree that was identical to that based on molecular data alone. These molecular and morphological characters present the same picture of Mallos and Mexitilia phylogeny. / Master of Science

The objective of this study was to determine how hole diameter, channel length, test organism motility, concentration and aerosol exposure time affected microbiological contamination of sealed flexible pouches. Nickel microtubes with 10 μm and 20μm hole diameters and lengths of 5 mm and 10 mm were used in various combinations to create seal defects in 128 retortable pouches. A 119,911 cm³, exposure chamber was used to distribute an aerosol with a particle size of 2.68 μm, infected with motile and isogenically mutated nonmotile <i>Pseudomonas fragi</i> TM 849 in concentrations of 10² or 10⁶ cells/mL. Fifteen and 30 minute aerosol exposure times were used. Six pouches tested positive for test organism growth after a 72 hour incubation period. Pouch contamination via microbial ingress was significant (P < .05) for test organism motility (motile) and concentration (10⁶ cells/mL). / Master of Science

The ''charge pump" electronic ballast circuit, which employs a charging capacitor and a high frequency ac source to implement the power factor correction (PFC), has become an attractive topology for ballasting the fluorescent lamps because it eliminates the use of a bulky boost inductor. But the high voltage stress on the semiconductor devices at light load conditions, the high total harmonic distortion (THO) of the line current, and the poor crest factor ( CF) of the lamp current in this circuit make it difficult to manufacture this circuit into a cost-effective ballast product. This thesis analyzes the problems associated with the "charge pump" electronic ballast, and proposes several innovative methods to solve the problems, resulting in a high performance and cost-effective technology. / Master of Science

During <i>Dictyostelium</i> development, glycogen degradation is a crucial event that provides glucose monomers that are utilized to synthesize the essential structural components for cellular differentiation. The degradation is catalyzed by the product of the glycogen phosphorylase-2 gene. Cloning and sequencing of the <i>gp</i>-2 gene revealed several repeated sequences in the promoter region that are putative regulatory sites. I present here the purification of a DNA binding protein that binds to the 3' "C" box sequence in the <i>gp</i>-2 promoter using a DEAE Sephacel resin and specific "C" DNA affinity column chromatography. With undifferentiated amoebae cell extract, a DNA binding protein migrated at 0.40 Rf and with 17 hr differentiated cell extract, the protein migrated at 0.32 Rf. Both the 0.32 and 0.40 Rf proteins were purified to homogeneity and showed to consist of three subunits of 18 kD, 35 kD and 62 kD (for 0.40 Rf) or 81 kD (for 0.32 Rf). Amino acid sequence analysis showed identity between a region of the 62 and 81 kD subunits. I conclude that the difference in the shifted 0.40 Rf and 0.32 Rf bands in EMSA is due to the 62 and 81 k.D subunits. A southwestern blot analysis of the 17 hr cell extract demonstrated that the DNA binding activity resides in the 81 kD polypeptide. The effect of pH and phosphatase inhibitors on a "conversion" between the 0.32 and 0.40 Rf bands was examined. The results suggest that phosphorylation may be involved in the "conversion" reaction. This study suggests that the purified protein may be a trans-acting factor that is involved in <i>gp</i>-2 regulation. / Master of Science

The objective of this study was to compare products fermented with two culture systems to two endpoints for the following characteristics: survival of the culture bacteria, changes in protein, lactose and galactose concentrations and sensory changes. Frozen yogurt was produced using a standard lowfat ice cream mix formulation, fermented with supplemented and traditional culture systems, and stored for 11 weeks at -20°C. Three methods of recovery were employed: Bifid Glucose Agar with the Repair Detection System and Roll Tubes, Bifid Glucose Agar with the Repair Detection System on plates incubated in an anaerobe jar with a GasPak™, and Maltose/Galactose Reinforced Clostridial Agar incubated in an anaerobe jar with a GasPak™. Statistical analysis indicated that the Repair Detection System provided significantly (p<.05) enhanced recovery of Bifidobacterium longum. Recovery of B. longum on BGA Plates and M/G RCA plates was approximately one-half log lower than recovery on BGA in roll tubes. Culture bacteria in both systems survived at approximately 5x10⁶ cfu/mL during frozen storage. Lactose and protein levels showed no significant changes or differences between the two culture systems. Generally, galactose levels were significantly higher (p<.05) in the traditional culture system fermented to pH 5.6 compared to the supplemented system fermented to the same endpoint. The manufactured products (supplemented and traditional) were not different from the commercial product with respect to flavor intensity of yogurt flavor, vanilla, sweetness and freshness. Acid flavor was usually more intense when product was fermented to a pH of 5.6. The commercial product was more smooth than the manufactured products. Consumers indicated a “like slightly” to “like moderately” response for the supplemented and traditional inoculated frozen yogurts. The study concluded that the culture bacteria do survive the environment well enough to meet proposed standards of identity for frozen yogurt. The presence of probiotic bacteria in the supplemented system seemed to cause little to no difference in such attributes as protein and lactose levels, and sensory evaluation. / Master of Science

The objective of this experiment was to determine whether norgestomet implant insertion following melengestrol acetate (MGA) administration altered LH pulse frequency and follicular dynamics. Multiparous Angus cows were randomly assigned to receive MGA (.5 mg*cow⁻¹*d⁻¹ ; MGA; n = 14) for 18 d or to receive MGA (.5 mg*cow·⁻¹ l*d⁻¹; MGA-N; n = 11) for 15 d and a norgestomet implant for 4 d beginning on d 15. Ultrasound was used to record images of each ovary in cows beginning on d 8 of MGA administration. On d 16, serial blood samples were collected from all cows in replicate one (MGA, n=6; MGA-N, n=6) for quantification ofLH pulse frequency. A persistent, dominant follicle was identified in all cows on d 8 ofMGA administration. Forty-three percent and 64% (P > .10) of MGA and MGA-N cows, respectively, initiated a new wave of follicular development during treatment that was the source of the ovulatory follicle. Pulse frequency of LH did not differ between MGA and MGA-N cows or between cows that ovulated a persistent (PERSIST) follicle and those that ovulated a follicle from a new follicular wave (NEW). Growth rate of the ovulatory follicle for the 7 d preceding ovulation was greater in PERSIST than in NEW cows (P < .01). Diameter of the owlatory follicle on the day preceding ovulation was greater in PERSIST cows than in NEW cows (P < .01). In conclusion, MGA administration caused a persistent follicle to develop, but that follicle was unable to be regressed consistently by supplemental norgestomet administration. / Master of Science