The experimental results of the current work have three parts. First, the synthesis and characterization of several new copolymers by the free-radical copolymerization between several highly substituted electron-deficient olefins and furan, benzofuran, indene, alphamethylstyrene, and divinyl ether is discussed. Electron-poor olefins used included dimethyl cyanofumarate, carbomethoxymaleic anhydride and tricarbomethoxyethene. The spontaneous reactions of these monomer pairs were also investigated in both bulk and solution. Second, the effect of synthesis temperature on the composition of the previously reported (co)polymers of styrene with tricarbomethoxyethene and dimethyl dicyanofumarate are given. A ceiling temperature for the synthesis of this copolymer was found to be 220°C. Attempted copolymerization of tetracarbomethoxyethene gave evidence of a small but detectable amount of reaction. Finally, detailed procedures for the synthesis of dimethyl cyanofumarate, carbomethoxymaleic anhydride and tricarbomethoxyethene are given, including a new synthesis of carbomethoxymaleic anhydride.

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ABSTRACT Purpose: The primary aim of the study (i.e. Chapter 3) was to compare the magnitude of retinal vascular reactivity in arterioles of varying diameter in healthy, young subjects. The secondary aims were to determine: a) if there are any order effects in terms of provoking vasoconstriction or vasodilation first; and b) the repeatability of the vascular reactivity measurements. An additional aim (i.e. Chapter 4) was to determine the effect of healthy aging on the relationship between retinal vascular reactivity and vessel diameter. Method: The sample comprised 10 healthy, young subjects (mean age 26.5 years, SD 4.04) and 7 healthy, older subjects (mean age 55.43 years, SD 5.41). Each subject from the young age group attended for three sessions. The first session was used to determine eligibility and select hemodynamic measurement sites. At sessions 2 and 3, O2 and CO2 were sequentially administered to the subjects using a face mask and sequential re-breathing circuit (to maintain standardized hyperoxia and hypercapnia). The order of vasoconstriction and vasodilation was varied across sessions 2 and 3. The design of the protocol was simplified for the subjects from the older age group. Each subject from the older group attended for one visit. O2 and CO2 were administered to the subjects using a face mask and sequential re-breathing circuit. The order of gas provocation was varied among the subjects (i.e. hyperoxia or hypercapnia first). For both groups, measurements of vessel diameter, centerline blood velocity and derived blood flow were acquired at each condition (i.e. baseline, during stabilized vasoconstriction, vasodilation, and recovery) at two discrete measurement sites along the supero-temporal arteriole. Results: The results of the repeated measures ANOVA showed a significant difference between the narrow and wide measurement sites for the younger group for flow (p??? 0.0003) and a significant influence of inspired gas provocation on flow for both protocols (p<0.0001). In addition, the interaction of measurement site and inspired gas provocation was significant (p<0.0001). The magnitude of retinal vascular reactivity showed a significantly greater blood flow response for the wide measurement site (p<0.0001). O2 provocation resulted in vasoconstriction that was still present up to 10 minutes after cessation of the stimulus (order effect of O2; p???0.046). No such order effect was apparent for CO2 provocation (order effect of CO2; p=0.352). The group mean blood flow Coefficient of Repeatability (COR) for the narrow measurement site was 0.74 ??l/min (relative to group mean flow of 4.85 ??l/min ?? SD 1.31) and for the wide measurement site was 1.49 ??l/min (relative to group mean flow of 11.29 ??l/min ?? SD 3.55). There was no difference between the young and the older age groups in retinal vascular reactivity for both the narrow (two-tailed Student t-test, p=0.8692) and wide (two-tailed Student t-test, p=0.2795) measurement sites. Conclusion: This study demonstrated that the magnitude of retinal vascular reactivity was greater for arteriolar measurement sites with wider baseline vessel diameters. In addition, it demonstrated that hyperoxic provocation resulted in a persistent vasoconstriction up to 10 minutes after cessation of the stimulus. The study demonstrated that the repeatability of retinal blood flow measurements in absolute terms is lower for smaller diameter vessels. Finally, this study also suggests that age does not affect the relationship between retinal vascular reactivity and vessel diameter.

M.Sc. / Please refer to full text to view abstract

Thesis (M.Sc.), Faculty of Engineering (Metallurgy and Materials Engineering), 1996

Kit-Hung Wong. / Thesis submitted in: October 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 77-86). / Abstracts in English and Chinese. / Acknowledgement --- p.III / Content --- p.IV / Abstract (in English) --- p.VI / Abstract (in Chinese) --- p.VIII / List of Compounds --- p.IX / List of Figures --- p.X / List of Abbreviations --- p.XI / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- p-Block Metallacarboranes --- p.2 / Chapter 1.2.1 --- C2B4 systems --- p.2 / Chapter 1.2.1.1 --- ´بCarbons-Adjacent´ة Metallacarboranes --- p.2 / Chapter 1.2.1.2 --- ´بCarbons-Apart´ة Metallacarboranes --- p.6 / Chapter 1.2.2 --- C2B9 systems --- p.7 / Chapter 1.2.3 --- C2B10 systems --- p.10 / Chapter 1.3 --- d-Block Metallacarboranes --- p.11 / Chapter 1.3.1 --- C2B9 systems --- p.11 / Chapter 1.3.2 --- C2B10 systems --- p.15 / Chapter 1.4 --- Objectives --- p.16 / Chapter Chapter 2 --- "Synthesis, Structural Characterization and Reactivity of Group13 Metallacarboranes" / Chapter 2.1 --- Introduction --- p.18 / Chapter 2.2 --- Synthesis and Spectroscopic Characterization --- p.19 / Chapter 2.3 --- Molecular Structure --- p.21 / Chapter 2.4 --- Conclusion --- p.26 / Chapter Chapter 3 --- "Synthesis, Structural Characterization and Reactivity of Group14 Metallacarboranes" / Chapter 3.1 --- Introduction --- p.27 / Chapter 3.2 --- Synthesis and Reactivity --- p.28 / Chapter 3.3 --- Characterization --- p.29 / Chapter 3.4 --- Discussion --- p.33 / Chapter 3.5 --- Conclusion --- p.35 / Chapter Chapter 4 --- "Synthesis, Structural Characterization and Reactivity d-Block Metallacarboranes" / Chapter 4.1 --- Introduction --- p.36 / Chapter 4.2 --- Synthesis and Characterization --- p.36 / Chapter 4.3 --- Molecular Structure --- p.43 / Chapter 4.4 --- Ultraviolet Spectroscopy --- p.49 / Chapter 4.5 --- Electrochemical Studies --- p.51 / Chapter 4.6 --- Reactivity --- p.53 / Chapter 4.7 --- Conclusion --- p.55 / Chapter Chapter 5 --- Conclusion --- p.57 / Chapter Chapter 6 --- Experimental Section --- p.60 / Reference / Appendix / Chapter I. --- Publication Based on the Research Findings --- p.86 / Chapter II. --- Crystal Data and Summary of Data Collection and Refinement --- p.87 / Chapter III. --- Atomic Coordinates and Thermal Parameter --- p.89 / Chapter IV. --- Bond Distances and Angles --- p.95

A substantial body of work exists to suggest that brain and spinal mechanisms react differently to nociceptive information. The current experiments were design to identify parallels and differences in the way the spinal cord processes nociceptive information, as compared to intact animals. In addition, pharmacological manipulations were employed to identify the opioid receptors activated by continuous shock, and to decipher at what synaptic level (e.g. pre or post synaptically) intermittent shock affects the release of endogenous opioids. A common dependent variable was used in all experiments to assess changes in nociceptive reactivity, the tail-flick test. The results revealed that intermittent and continuous stimulation have an opponent relationship on nociceptive processing in the isolated spinal cord. Continuous stimulation (3, 25-s continuous 1.5 mA tail-shocks) induced an antinociceptive response that was attenuated by prior exposure to brief (80 ms) intermittent shock (Experiment 1). When intermittent shock was given after continuous shock, intermittent shock failed to attenuate continuous shock-induced antinociception (Experiment 2). The impact of intermittent shock on continuous-shock induced antinociception decayed after 24 hours (Experiment 3). Intermittent and continuous shock enhanced the antinociceptive consequences of a moderate dose of systemic morphine (5 mg/kg) (Experiment 4). Continuous shock-induced antinociception was attenuated by equal molar concentrations of CTOP (µ opioid antagonist) and Nor-BNI (κ opioid antagonist), but not naltrindole (δ opioid antagonist) (Experiment 5). Intermittent shock failed to attenuate the antinociception induced by DAMGO (µ opioid agonist) or Dynorphin A (κ opioid agonist).