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This thesis presents the development of the Geonium Chip, a planar Penning trap. The Geonium Chip consists of the five electrodes of a cylindrical Penning trap projected onto the surface of a microfabricated chip. Beneath the chip is a planar magnetic field source currently made from coils of niobium titanium wire. Traditionally the magnetic field source is a large superconducting solenoid, replacing this with a planar source makes the setup scalable, portable and economical. The Geonium Chip, with its magnetic field source and detection electronics, need to be placed in a cryostat. In this thesis, I describe the development of the cryogenic setup with particular emphasis on the design and optimisation of the non-destructive detection system. I detail the cryogenic wiring of the cryostat including the thermalisation of high current wires and the noise reduction techniques employed on the detection signal. In addition, I explore the parasitic capacitances of the Geonium Chip using microwave network analysis and describe the testing of the magnetic field source at 4 K. Finally, I discuss the generation of electrons within the trap and the results of our first attempts at trapping a cloud of electrons. Together, the chip and the magnetic field source can be used to trap ions for ultraaccurate mass spectrometry or an electron for single microwave photon detection. A single microwave photon detector is a tool that is currently still missing in quantum technology and is needed for determining the quantum state of microwave radiation fields. This is vital for quantum communication and cryptography. Additionally, using the Geonium Chip as a mass spectrometer has the potential to lead to very accurate mass spectrums without the need for frequent calibration. Finally, eliminating the expensive superconducting solenoid will make accurate mass spectrometry available to a wider market.

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In this investigation, venom from the giant Neotropical hunting ant Dinoponera australis (Order: Hymenoptera) has been harvested and subjected to chromatographic separations for the purpose of elucidating possible peptides that display neuroactivity by bioassay guided venom fractionation (BGVF). The venom of this arcane solitary predator paralyzes small invertebrate prey and causes highly exaggerated pain in large vertebrates. The hypothesis that the venom has a peptide component highly effective in modulating neuronal conduction by depolarization of cellular membranes has been tested and subsequent biochemical characterization has been performed to elucidate the primary structure. The data suggests that the modulation of neuronal conduction appears to result from the formation of a de novo pore that allows non-selective ion movements in a concentration dependent manner. The venom contains a variety of proteinaceous candidates and one particular peptide from the venom, -Dinoponeratoxin Da-1837, has been observed to cause very fast, large and sustained depolarization in two types of normally quiescent peripheral neurons (primary cultures of trigeminal and dorsal root ganglia) in whole cell patch clamp recordings. The profound depolarization is due to non-selective cationic flux which is irreversible at high concentrations. Preliminary studies suggest that the peptide also has a minor inhibitory effect on voltage-gated sodium channels, which does not contribute to the depolarization. Membrane assays with microsomes, fluorescent probes and lipid bilayers confirmed peptide-induced non-selective and concentration dependent permeabilization of the membrane. The primary structure of the peptide was determined by iterations of product ion scans in multiple configurations utilizing high resolution tandem mass spectrometry, commonly referred to as MS-MS data dependent acquisition. -DpTx Da-1837 is an eighteen residue peptide that is highly hydrophobic, positively charged at physiological pH and has one atypical post translational modification, i.e. C-terminal peptidyl-lysine. The authentication of the toxin was confirmed by the successful solid phase synthesis of an analog that showed neither biochemical nor physiological variation from the properties of the peptide isolated from Dinoponera australis. The conclusion of this study was the creation of derivative analogs that provide the platform for the first fundamental step in drug discovery: establishing the structure-function relationship. Although the purpose of these cytolytic peptides in venom may be to capture prey or discourage predation, the discoveries of new molecules that affect cell viability by interactions with the cellular envelope provide the genesis for studies of targeted cell death. As a novel anti-microbial agent or as a potent tumor suppressor, the development of peptide derivatives could also help direct the development of new therapeutic interventions.

A study of methods for determining the relative abundances of the chlorine isotopes, and the results of mass spectrometric analyses of several chlorine-containing substances. Small variations are shown to exist in nature between the relative abundances of the chlorine isotopes in halite samples from at least two different localities. Other studies involving chlorine isotopes and their possible fractionation are included. / Thesis / Master of Science (MSc)

Paclitaxel is a very important anticancer drug commonly called Taxol®. We know from previous work (Hoffman, et al., 1998) that Taxol exists in filbert, Corylus avellana L. material. Quantification of Taxol in filbert plant material is painstaking and hitherto was accomplished by rapidly processing single batches in a complicated procedure (Hoffman, et al., 1998), which seemingly unavoidably, was accompanied by some degradation. However for extraction, testing, plant physiological and horticultural purposes a simplified method of determining Taxol yield is required. All simplified methods tested were found limited by rapid degradation of Taxol. Under these conditions not only is the sought product broken down, but we were unable to distinguish Taxol precursors from degradation products. Thus it was decided to go back to first principles and study the degradation of Taxol in vitro. Degradation kinetics of Taxol was studied using electrospray ionization mass spectrometry (ESIMS) to identify possible Taxol adducts and degradation products. Our preparation for ESIMS analysis by experimental necessity involved various other components. Since some of these components interacted with the degradation products, we developed a program to distinguish these putative adducts from spurious components found in the system and we were able to plot the pH dependence of Taxol degradation in this system at room temperature (approximately 25oC). The results of the mass spectrometric analysis of these degradants were found dependent on pH and time. Our results show major degradation at pH 9 and beyond, plus minor degradation at pH 5. Two optimum pHs for stability were found at pH 4 and pH 7. This data varies slightly from the published results Dordunoo and Burt (1996). Our smoother curves define two pHs events in this pH range which to our knowledge, have not been reported and our temperature was lower. We hope that this information will help us extract Taxol more efficiently with greater yield from novel plant sources, e.g. hazel (filbert) tree, Corylus avellana L. The possibility of Taxol dimer formation in solution and perhaps in vivo can be inferred, but not proven, in this work. This dimer, may exist, in dynamic equilibrium with parent compound, Taxol. / Graduation date: 2006

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No description available.