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Noncholinergic neurotransmission was studied in vitro in the guinea pig inferior mesenteric ganglion (IMG) using the technique of intracellular recording. First, the role of substance P (SP) in noncholinergic transmission was examined. Forty-four percent of IMG neurons depolarized upon superfusion of SP (1-10 x 10⁻⁷M); however, some neurons that were insensitive to SP still exhibited slow excitatory potentials (EPSPs) in response to nerve stimulation. During exposure to SP, slow EPSPs were depressed by 52% compared to paired control EPSPs. In animals treated with systemic doses of capsaicin (50-350 mg/kg), mean slow EPSP amplitude was 3.5 mV compared to 6.8 mV in untreated animals. Arginine-vasopressin (AVP) was tested for its electrophysiological effects on IMG neurons and synaptic transmission. AVP (0.5-10 x 10⁻⁷M) produced a depolarization in 67% of neurons, accompanied by an increase in membrane resistance of 44%. The depolarizations and increase in resistance were blocked by a specific V₁ receptor antagonist. During AVP-induced depolarizations, slow EPSPs were reversibly depressed in the majority of neurons by a mean of 71% relative to paired control EPSPs. The V₁ antagonist blocked slow EPSPs in only 10% of neurons tested. A group of neurons exhibiting slow EPSPs was exposed separately to both AVP and SP. Some neurons were exclusively sensitive to either SP or AVP, others were sensitive to both peptides, and still others were sensitive to neither peptide. The physiologic role of noncholinergic transmission was examined using a preparation consisting of a segment of distal colon attached to the IMG. Distension of the colon segment produced a slow depolarization resistant to cholinergic antagonists in 44% of IMG neurons. Distension-induced noncholinergic depolarizations increased in amplitude with colonic intraluminal pressure and with membrane hyperpolarization, and were accompanied by an increase in membrane input resistance of 21%. Capsaicin in vivo reduced the number of neurons exhibiting the noncholinergic mechanosensory depolarization, and in vitro capsaicin and SP desensitization reduced the amplitude of the depolarization. These results suggest that (1) both SP and AVP may be transmitters of noncholinergic potentials in the IMG, (2) some IMG neurons receive heterogeneous peptidergic innervation, and (3) noncholinergic transmission in the IMG is involved in sensory regulation of visceral autonomic function.

Tsang Kwai Fan. / Thesis submitted in: December 2003. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 85-101). / Abstracts in English and Chinese. / Abstracts --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Table of Abbreviations --- p.vi / Table of Contents --- p.vii / Chapter Chapter One: --- Introduction of Curcumin / Chapter 1.1 --- What is curcumin? --- p.1 / Chapter 1.2 --- Chemistry of curcumin --- p.2 / Chapter 1.3 --- History of using turmeric --- p.3 / Chapter 1.4 --- Curcumin in biological system --- p.4 / Chapter 1.5 --- Current researches on curcumin --- p.7 / Chapter 1.6 --- Curcumin Toxicity --- p.13 / Chapter Chapter Two: --- Introduction of Muscle Regeneration / Chapter 2.1 --- Reasons for studying muscle regeneration --- p.15 / Chapter 2.2 --- Skeletal muscle: functions and structure --- p.16 / Chapter 2.3 --- Muscle healing process --- p.17 / Chapter 2.4 --- Muscle formation --- p.31 / Chapter 2.5 --- Current trends in enhancing muscle regeneration --- p.37 / Chapter Chapter Three: --- Methodology / Chapter 3.1 --- Animals --- p.41 / Chapter 3.2 --- Histology --- p.42 / Chapter 3.3 --- Measurement of cross-sectional area of muscles --- p.42 / Chapter 3.4 --- Two-dimensional electrophoresis --- p.43 / Chapter 3.5 --- Protein identification by matrix-assisted laser desorption time-of-flight (MALDI-TOF) --- p.47 / Chapter 3.6 --- Cell culture --- p.50 / Chapter 3.7 --- In vitro cell proliferation assay / Chapter 3.8 --- In vitro differentiation assay --- p.51 / Chapter 3.9 --- Transfection and Secreted Alkaline Phosphatase (SEAP) reporter assay --- p.52 / Chapter Chapter Four: --- Results / Chapter 4.1 --- Effects of curcumin on muscle regeneration --- p.58 / Chapter 4.2 --- Two-dimensional electrophoresis --- p.59 / Chapter 4.3 --- Effect of curcumin on myogenic cell proliferation --- p.61 / Chapter 4.4 --- Effect of curcumin on myogenic cell differentiation --- p.61 / Chapter 4.5 --- Signal transduction --- p.63 / Chapter 4.6 --- Legends and table --- p.65 / Chapter Chapter Five: --- Discussion --- p.77 / Chapter Chapter Six: --- Conclusions --- p.84 / References --- p.85 / Appendices --- p.102

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Theories in operating systems are relatively matured, but implementations are hard compared to many areas in computer science. For example, virtual memory has been around for more than 20 years since its introduction, but, to understand how an operating system supports virtual memory is not a trivial task, let alone implementation. Minix is an operating system that has been designed for educational purpose. It¡¦s a good starting point for a novice who wants to learn operating systems. The third version of Minix has been moved towards a true microkernel design and targeted at small computers and embedded systems. The advantages of microkernel architecture is its high fault tolerance and high modularity design which can make it much more flexible for versatile applications on embedded systems. However, to the best of our knowledge, Minix 3 only runs on Intel-based machine so far. The objective of this thesis is thus to port Minix 3 to ARM-Based embedded systems, to make it an experimental microkernel for embedded systems. Also, due to the incompatibility between the segmented memory model used by Minix 3 on IA-32 and the unsegmented memory model support by ARM, we also provide an API to simplify the porting effort.

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Visualization can be an effective way to explore and understand abstract data. Due to the rapidly changing technological environment of sys admin work and the scale of data involved, enhanced visualizations might provide benefit in this domain; however, despite research efforts, to-date the tools for system administrators (sys admins) minimally employ the use of interactivity in models and provide limited visualizations in tools. This may be because sys admins have a culture of command-line interface (CLI) use that is at odds to the graphical user interface (GUI) that accompanies most tools that incorporate interactive visualizations. We designed a two phase study to gain a better understanding about the work of sys admins, their current tool environment, their preferences for CLI and GUI based tools, and their perspective about how the inclusion of interactive visualizations in tools and system models might enhance their routines. The first phase of contextual inquiries and semi-structured interviews with 37 participants gave us a rich understanding of system admin work practices and their desired functionality for future tools. In the second phase, an on-line survey with 331 sys admins allowed us to generalize our findings. Based on our research, we generated recommendations for desired tool features in each of the sub-domains of sys admin work (i.e., network, virtualization etc.,). We also conducted an analysis of the type of visualizations that could be implemented in future tools to support the challenging nature of sys admin work.