A CMOS implementation of a True-Q Flip Flop is presented. It can perform either as an asynchronous storage element in micropipelines or a part of the synchronizer. It is capable of double-edge triggering which latches data at both the rising and the trailing edges. It is also free of the metastability state problem. Some analog and digital circuits are incorporated with a true double-edge triggered Flip Flop (DETFF) making it a True-Q Flip Flop. A True-Q Flip Flop outputs an acknowledge signal only after the Q and NQ are stabilized. Therefore, if the proceeding stages utilize this acknowledge signal as the triggering signal, then, the value of Q from the flip flop will not be received by the next stage if Q is in a metastable state. The number of transistors used in this implementation of True-Q flip flop is 90. Due to the overhead of circuit complexity, the time delay from Request to Acknowledge signal is 6.5ns. / Graduation date: 1995

Graduation date: 1994

Porous tin oxide nanotubes were obtained by vacuum infiltration of tin oxide nanoparticles into porous aluminum oxide membranes, followed by calcination. The porous tin oxide nanotube arrays so prepared were characterized by FE-SEM, TEM, HRTEM, and XRD. The nanotubes are open-ended, highly ordered with uniform cross-sections, diameters and wall thickness. The tin oxide nanotubes were evaluated as a substitute anode material for the lithium ion batteries. The tin oxide nanotube anode could be charged and discharged repeatedly, retaining a specific capacity of 525 mAh/g after 80 cycles. This capacity is significantly higher than the theoretical capacity of commercial graphite anode (372 mAh/g) and the cyclability is outstanding for a tin based electrode. The cyclability and capacities of the tin oxide nanotubes were also higher than their building blocks of solid tin oxide nanoparticles. A few factors accounting for the good cycling performance and high capacity of tin oxide nanotubes are suggested. / Singapore-MIT Alliance (SMA)

Thesis (M.Sc. (Pharmaceutical Chemistry)--Potchefstroom University for Christian Higher Education, 2002.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph.D.)--Stanford University, 2006. / Adviser: Krishna C. Saraswat. Includes bibliographical references (p. 160-177)

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Nitric oxide (NO) is a short-lived free radical that plays a critical role in the regulation of cellular signalling. Mast cell (MC) derived NO and exogenous NO regulate MC activities including the inhibition of MC degranulation. At a molecular level the intermediate metabolites of NO modify protein structure and function through several mechanisms including protein tyrosine nitration. To begin to elucidate the molecular mechanisms underlying the effects of NO in MC, we investigated protein tyrosine nitration in human mast cell lines HMC-1 and LAD2 treated with the NO donor S-nitrosoglutathione (SNOG). Using two dimensional gel western blot analysis with an anti-nitrotyrosine antibody together with mass spectroscopy we identified aldolase A, an enzyme of the glycolytic pathway, as a target for tyrosine nitration in MC. S-nitrosoglutathione treatment also reduced the Vmax of aldolase in HMC-1 and LAD2. Nuclear magnetic resonance (NMR) analysis showed that despite these changes in activity of a critical enzyme in glycolysis, there was no significant change in total cellular ATP content, although the AMP/ATP ratio was altered. Elevated levels of lactate and pyruvate suggested that SNOG treatment enhanced glycolysis. Reduced aldolase activity was associated with increased intracellular levels of its substrate, fructose-1,6-bisphosphate (FBP). Interestingly, FBP inhibited IgE-mediated MC degranulation and intracellular Ca2+ levels in LAD2 cells. In addition to aldolase, 15-hydroxy prostaglandin dehydrogenase (PGDH), a critical enzyme in the metabolism of PGE2, was identified as a prominent target for tyrosine nitration in LAD2 cells. Thus for the first time we report evidence of protein tyrosine nitration in human MC lines and identify aldolase A as a prominent target in HMC-1 and LAD2; and PGDH in LAD2 cells. The post translational nitration of aldolase A and PGDH may be important pathways that regulate MC phenotype and function. / Experimental Medicine

Thesis (Ph. D.)--Washington State University, December 2006. / Includes bibliographical references (p. 122-130).