Thesis (Ph. D.)--University of Hong Kong, 1992.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 87-88). Also available in electronic format on the Internet.

Thesis (M.C.S.)--Carleton University, 1988. / Also available in electronic format on the Internet.

Thesis (doctoral) -- Friedrich-Alexanders-Universität Erlangen, 1901. / Vita. Bibliography: p. 34.

Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on July 13, 2009). Includes bibliographical references (p. 104-107).

abstract: This dissertation presents three essays in economics. Firstly, I study the problem of allocating an indivisible good between two agents under incomplete information. I provide a characterization of mechanisms that maximize the sum of the expected utilities of the agents among all feasible strategy-proof mechanisms: Any optimal mechanism must be a convex combination of two fixed price mechanisms and two option mechanisms. Secondly, I study the problem of allocating a non-excludable public good between two agents under incomplete information. An equal-cost sharing mechanism which maximizes the sum of the expected utilities of the agents among all feasible strategy-proof mechanisms is proved to be optimal. Under the equal-cost sharing mechanism, when the built cost is low, the public good is provided whenever one of the agents is willing to fund it at half cost; when the cost is high, the public good is provided only if both agents are willing to fund it. Thirdly, I analyze the problem of matching two heterogeneous populations. If the payoff from a match exhibits complementarities, it is well known that absent any friction positive assortative matching is optimal. Coarse matching refers to a situation in which the populations into a finite number of classes, then randomly matched within these classes. The focus of this essay is the performance of coarse matching schemes with a finite number of classes. The main results of this essay are the following ones. First, assuming a multiplicative match payoff function, I derive a lower bound on the performance of n-class coarse matching under mild conditions on the distributions of agents' characteristics. Second, I prove that this result generalizes to a large class of match payoff functions. Third, I show that these results are applicable to a broad class of applications, including a monopoly pricing problem with incomplete information, as well as to a cost-sharing problem with incomplete information. In these problems, standard models predict that optimal contracts sort types completely. The third result implies that a monopolist can capture a large fraction of the second-best profits by offering pooling contracts with a small number of qualities. / Dissertation/Thesis / Ph.D. Economics 2011

<strong>Chapter One</stong> provides an introduction to the chemistry of pentalene and its derivatives encompassing ligand synthesis, organometallic chemistry, and in particular ethylene polymerisation. In the second half, cationic polymerisation is introduced encompassing both main-group and transition-metal initiated polymerisations. The limitations of cationic ethylene polymerisation are highlighted. <strong>Chapter Two</stong> describes the synthesis of a series of related complexes based on the Pn*MCp^R(X) motif for application as ethylene polymerisation catalysts. The products are characterised by NMR spectroscopy, single crystal X-ray diffraction, elemental analysis and, where relevant, EPR spectroscopy. <strong>Chapter Three</stong> details the application of aforementioned Pn*MCp^R(X) complexes as ethylene polymerisation catalysts, tested in solution co-catalysed by methylaluminoxane, and in the slurry phase, immobilised on a variety of inorganic supports. Very high activities are observed for the zirconium congeners of this non-classic polymerisation motif, with the Cp ligand observed to affect activity more dramatically than the "X" ligand. <strong>Chapter Four</stong> gives an account of mechanistic investigations examining the activity of the Pn*MCp^R(X) catalysts. Pre-catalyst activation studies implicate the formation of cationic derivatives, which are rationally synthesised. The unexpected activity of [Pn*ZrCp]⁺ towards ethylene polymerisation is investigated by in-situ gas uptake measurements and small molecule activation studies, which do not readily accommodate a coordination-insertion mechanism. An alternative cationic initiation mechanism is proposed and explored. <strong>Chapter Five</stong> describes the synthesis of titanium and zirconium hydride and deuteride complexes. Using either LiAlH₄/D₄ or H₂/D₂ as the hydrogen source, trimetallic hydride clusters are synthesised. Preliminary investigations into their reactivity with small molecules is presented. <strong>Chapter Six</stong> details the synthesis of reduced permethylpentalene titanium complexes. Chlorine atom abstraction, scrambling of the Pn* ligand, and dinitrogen activation was observed depending on the nature of the reducing agent and the stoichiometry employed. <strong>Chapter Seven</stong> provides experimental details and characterising data for the complexes presented in the preceding five chapters.

Doctor of Philosophy / Department of Chemistry / Stefan H. Bossmann / The therapeutic peptide sequence D-K₆L₉: LKLLKKLLKKLLKLL-NH₂ was developed for treating bacterial infections and solid tumors. It is effective against both conditions, because it is capable of targeting negatively charged surface domains due to its positive charge and the presence of hydrophobic units. Here, the peptide was modified with two extra amino acids (Serine and Alanine) at both, C and N terminals, resulting in SA-D-K₆L₉-AS. The sequence and structure of the modified peptide were determined by means of 2D ¹H-¹H -COSY, NOESY, and TOCSY-NMR spectroscopy. The 3D structure of the peptide in the solution phase was generated by CNS software utilizing data generated by NOE spectroscopy. This peptide was tested on the following mouse cancer cell lines: GL 26 (glioma), 4T1 (metastasizing breast cancer), NSC (neural stem cells), and pig monocytes. The LC50 values of the modified peptide were found to be 5- 10 times more active than of the original D-K₆L₉. To gain insight into its biochemical mode of action, SA-D-K₆L₉-AS tagged with a Rhodamine dye was incubated with GL 26 cancer cells. Sequential confocal imaging (every 30 seconds) revealed that the peptide interacts with cell membranes according to the carpet mechanism, and then becomes internalized into the cytoplasm in less than 5 min. and localizes in the mitochondria. This peptide is found to be toxic to neuronal stem cells and monocytes as well, showing the same mechanisms of interaction. To avoid the non-specific toxicity of the peptide for in-vivo applications, highly mesoporous silica nanoparticles (MSN) were synthesized, which served as a “container” for drug delivery. The peptide was then loaded into the MSN. MSN were further coated with a polysilazane as “gift wrap” (gatekeeper) after loading the peptide. This gatekeeper forms a shell that contains the peptide inside the MSN. While inside the MSN, the peptide shows no toxicity at 24 hours and subsequent slow release of its payload into the cytoplasm within 72 hours. This technology could be very useful for in-vivo cancer therapy by means of targeted delivery to the cancer site with appropriate surface modification of MSNs.

Cette thèse porte sur le devenir atmosphérique des Composés Organiques Volatils (COV) oxygénés, utilisés comme solvants, ou additifs aux carburants. Dans ce travail, les premières études cinétiques de réaction avec le radical OH de sept esters ont été effectuées, dans un domaine de température 243-373 K, à l’aide de la technique de Photolyse Laser Pulsée couplée à la Fluorescence Induite par Laser (PLP-FIL). Les constantes de vitesse de réaction des esters étudiés avec le radical OH et l’atome Cl ont également été déterminées par une méthode relative à température ambiante et pression atmosphérique. Pour ces esters, excepté le formate d' isopropyle, le présent travail constitue la première étude de leurs réactions avec l’atome Cl. En utilisant cette même méthode, les réactivités de deux alcools isomères vis à vis de l’atome Cl, en fonction de la température, ont aussi été déterminées. Des mesures de composés carbonylés en air ambiant ont été effectuées à Shanghai et à Pékin en octobre 2009. Les concentrations observées les plus importantes ont été celles de l'acétone, le formaldehyde et l'acétaldehyde. / In this work, kinetic studies for the gas-phase reactions of OH radical with seven saturated esters were firstly carried out, over the temperature range of 243 – 373 K, by using the Pulsed Laser Photolysis- Laser Induced Fluorescence (PLP-LIF) technique. Using the smog chamber technique, the rate coefficients for reactions of the above esters with OH and Cl were also measured at room temperature and one atmosphere. This work provides the first kinetic study for Cl atom reactions with the studied esters except for isopropyl formate. In addition, the temperature dependence of the rate coefficients for Cl reactions with two isomeric alcohols was firstly determined. Atmospheric levels of ambient carbonyl compounds as well as their diurnal variations were investigated during the period of October 2009 in Shanghai and Beijing. The most abundant carbonyls were acetone, followed by formaldehyde and acetaldehyde.

Electroplated zinc finishes have been widely used in the packaging of electronic products for many years as a result of their excellent corrosion resistance and relatively low cost. However, the spontaneous formation of whiskers on zinc electroplated components, which are capable of resulting in electrical shorting or other damaging effects, can be highly problematic for the reliability of long life electrical and electronic equipment. To date, most research has focused on tin whiskers and much less attention has been paid to zinc whisker research. A number of mechanisms to explain zinc whisker growth have been proposed, but none of them are widely accepted and some are in conflict with each other. This study has investigated the mechanism for whisker growth from three commercial zinc electroplated coatings on mild steel substrates. Firstly, whisker growth from an alkaline cyanide-free zinc electrodeposit was studied. A reduction in deposition current density (from 50 to 5 mA/cm2) and an increase in deposit thickness (from 2 to 15 μm) both contributed to reduced whisker growth. In terms of the mechanisms of whisker growth, it was observed that the presence of spherical raised surface features (nodules) with cavities beneath, promoted whisker growth by markedly shortening the incubation time from ~ 5 months to ~ 4 weeks. More importantly, the time dependent recrystallisation of the as-deposited columnar structure is closely associated with whisker growth from both nodules and planar regions of the deposit. The formation of Fe-Zn intermetallic compounds (IMCs) was not observed at either the Fe/Zn interface or within the electroplated coatings and does not appear to be associated with Zn whisker growth. Whisker growth from an acid chloride zinc electroplated coating and a Zn-Ni alloy electroplated coating were also investigated. These two coatings were immune to whisker growth after 18 months of storage at room temperature, regardless of deposition current density, deposit thickness and substrate surface modification. Finally, the effect of potential mitigation strategies on whisker growth was evaluated. Exposure to elevated temperatures (50 to 150°C) for 24 hours promoted whisker growth by reducing the incubation time for whiskers to first appear from less than 4 weeks to less than 10 days, whilst whisker growth was significantly retarded when samples were subjected to a short period of thermal treatment (50 to 150°C) for 0.5 hour. More importantly, for a short period of thermal treatment, whisker mitigation became increasingly effective as the treatment temperature was raised. In addition, the formation of a trivalent chromium passive coating on the alkaline cyanide-free zinc electrodeposits immediately after deposition was not an effective mitigation method to retard whisker growth.