by William, Wai-lun Lam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 85-95). / Chapter I. --- Introduction --- p.1 / Chapter II. --- Our Approach --- p.9 / Chapter III. --- Results and Discussion - Synthetic Strategy --- p.29 / Chapter IV. --- Results and Discussion - Pharmacological Activity --- p.44 / Chapter V. --- Conclusion --- p.49 / Chapter VI. --- Further Development --- p.53 / Chapter VII. --- Experimental Section --- p.55 / Chapter VIII. --- References --- p.85 / Chapter IX. --- Supplementary Materials --- p.96

by Chu, Pui-ya. / Thesis (M.Phil.)--Chinese University of Hong Kong. / Bibliography: leaves 115-126. / ACKNOWLEDGEMENT / LIST OF ABBREVIATIONS / ABSTRACT --- p.1 / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- PLATELET-ACTIVATING FACTOR (PAF) --- p.4 / Chapter 1.1.1 --- Metabolism of PAF --- p.4 / Chapter 1.1.1.1 --- Biosynthesis of PAF --- p.4 / Chapter 1.1.1.2 --- Degradation of PAF --- p.9 / Chapter 1.1.2 --- Systemic effects of PAF --- p.12 / Chapter 1.1.3 --- Structure - activity relationship of PAF --- p.16 / Chapter 1.2 --- PAF RECEPTORS --- p.19 / Chapter 1.2.1 --- PAF receptor on platelets --- p.19 / Chapter 1.2.2 --- PAF receptor on leukocytes --- p.20 / Chapter 1.2.3 --- PAF receptor on macrophages --- p.20 / Chapter 1.2.4 --- Antagonists of PAF --- p.20 / Chapter 1.2.4.1 --- Nonspecific inhibitors of PAF --- p.21 / Chapter 1.2.4.2 --- Specific antagonists of PAF --- p.21 / Chapter 1.3 --- SECOND MESSENGER SYSTEMS OF PAF --- p.22 / Chapter 1.3.1 --- Adenylate cyclase - cyclic adenosine mono- phosphate system --- p.26 / Chapter 1.3.2 --- Phospholipase C - phosphatidylinositol system --- p.28 / Chapter 1.3.3 --- Intracellular calcium --- p.29 / Chapter 1.3.4 --- The role of prostaglandins and leukotrienes --- p.30 / Chapter 1.3.5 --- Protein kinase C --- p.30 / Chapter 1.3.5.1 --- Dual action of PKC --- p.31 / Chapter 1.3.5.2 --- Down regulation of PKC --- p.33 / Chapter 1.4 --- THE FUNCTION OF MACROPHAGES --- p.33 / Chapter 1.4.1 --- Phagocytosis --- p.34 / Chapter 1.4.2 --- Antigen presentation --- p.34 / Chapter 1.4.3 --- Release of cytokines --- p.34 / Chapter 1.4.4 --- Respiratory burst --- p.35 / Chapter CHAPTER 2 --- METHODS / Chapter 2.1 --- PREPARATION OF PERITONEAL MACROPHAGES --- p.37 / Chapter 2.1.1 --- Preparation of reagents --- p.37 / Chapter 2.1.2 --- Preparation of peritoneal macrophages --- p.37 / Chapter 2.2 --- RADIOLIGAND BINDING ASSAY --- p.38 / Chapter 2.2.1 --- Reagents --- p.38 / Chapter 2.2.2 --- [3H]-PAF binding to TG-PEC --- p.39 / Chapter 2.2.2.1 --- Preparation of thioglycollate-elicited peritoneal macrophages --- p.39 / Chapter 2.2.2.2 --- Preparation of working solutions --- p.39 / Chapter 2.2.2.3 --- Assay of [3H]-PAF binding --- p.40 / Chapter 2.2.3 --- [3H]-PAF binding to resident PEC --- p.40 / Chapter 2.2.3.1 --- Preparation of resident peritoneal mcrophages --- p.41 / Chapter 2.2.3.2 --- Preparation of working solutions --- p.41 / Chapter 2.2.3.3 --- Assay of [3H]-PAF binding --- p.41 / Chapter 2.2.4 --- Preparation of drugs --- p.41 / Chapter 2.2.5 --- Data analysis --- p.42 / Chapter 2.3 --- MEASUREMENT OF INOSITOL PHOSPHATES --- p.42 / Chapter 2.3.1 --- Preparation of reagents --- p.42 / Chapter 2.3.2 --- Dowex column preparation --- p.43 / Chapter 2.3.3 --- Cell plating in 24 - well plastic trays --- p.44 / Chapter 2.3.4 --- Determination of total inositol phosphates --- p.44 / Chapter 2.3.5 --- Column separation --- p.45 / Chapter 2.3.6 --- Determination of inositol trisphosphate (IP3) --- p.46 / Chapter 2.4 --- MEASUREMENT OF INOSITOL PHOSPHATES ACCUMULATION AFTER PROLONGED PMA PRETREATMENT --- p.46 / Chapter 2.4.1 --- Preparation of phorbol-12-myristate-13-acetate (PMA) solutions --- p.47 / Chapter 2.4.2 --- Preparation of cells with PMA --- p.47 / Chapter 2.5 --- DETERMINATION OF SUPEROXIDE ANION PRODUCTION --- p.47 / Chapter 2.5.1 --- Preparation of drugs --- p.47 / Chapter 2.5.2 --- Assay of superoxide anion production --- p.48 / Chapter 2.5.3 --- Data analysis --- p.48 / Chapter 2.6 --- STATISTICAL METHOD --- p.48 / Chapter CHAPTER 3 --- RESULTS / Chapter 3.1 --- [3H]-PAF BINDING TO TG-PEC --- p.50 / Chapter 3.1.1 --- General properties --- p.50 / Chapter 3.1.2 --- Stereospecific of PAF receptor --- p.57 / Chapter 3.1.3 --- Comparison of [3H]-PAF binding to TG-PEC and TG-PMΦ from Balb/c mice --- p.57 / Chapter 3.1.4 --- Inhibition of specific binding of [3H]-PAF to murine and guinea pig TG-PEC by PAF --- p.57 / Chapter 3.1.5 --- Effects of PAF antagonists on the binding of [3H]- PAF to TG-PEC from Balb/c mice and guinea pigs --- p.60 / Chapter 3.1.6 --- Scatchard analysis of [3H]-PAF binding to murine and guinea pig TG-PMΦ --- p.65 / Chapter 3.2 --- SUPEROXIDE ANION PRODUCTION IN PERITONEAL MACROPHAGES --- p.69 / Chapter 3.2.1 --- Superoxide anion production induced by PAFin murine and guinea pig TG-PMΦ --- p.69 / Chapter 3.2.2 --- Effect of PMA on superoxide anion production in murine and guinea pig TG-PMΦ --- p.69 / Chapter 3.2.3 --- Effect of calcium ionophore on superoxide anion production in murine and guinea pig TG-PMΦ --- p.75 / Chapter 3.2.4 --- Effect of PAF antagonists on PAF - induced superoxide anion production in guinea pig TG-PMΦ --- p.75 / Chapter 3.3 --- PHOSPHOLIPASE C - PHOSPHATIDYLINOSITOL SYSTEM IN PERITONEAL MACROPHAGES --- p.79 / Chapter 3.3.1 --- Effect of PAF on the accumulation of inositol phosphates in the absence of LiCl --- p.79 / Chapter 3.3.2 --- Effect of PAF on the accumulation of inositol phosphates in the presence of LiCl --- p.79 / Chapter 3.3.2.1 --- Time course of [3H]-inositol phosphates accumulation induced by PAF in TG-PMΦ --- p.86 / Chapter 3.3.2.2 --- Effect of PAF on the accumulation of [3H]-IPs in TG- PMΦ from Balb/c mice and guinea pigs --- p.86 / Chapter 3.3.2.3 --- Effect of PAF antagonists on PAF-induced [3H]-IPs accumulation in TG-PMΦ from Balb/c mice and guinea pigs --- p.86 / Chapter 3.3.2.4 --- Effect of PMA on PAF-induced [3H]-IPs formation in TG-PMΦ from Balb/c mice and guinea pigs --- p.90 / Chapter 3.3.2.5 --- Effect of prolonged PMA pretreatment on PAF and PMA-induced [3H]-IPs accumulation in murine and guinea pig TG-PMΦ --- p.90 / Chapter 3.4 --- STUDIES OF RESIDENT PEC FROM Balb/c MICE --- p.96 / Chapter 3.4.1 --- Binding of 2nM [3H]-PAF to Balb/c mice resident PEC --- p.96 / Chapter 3.4.2 --- PAF-induced [3H]-IPs accumulation in murine resident PMΦ --- p.100 / Chapter 3.4.3 --- Binding of 0.2 nM [3H]-PAF to Balb/c mice resident PEC --- p.100 / Chapter 3.4.4 --- Superoxide anion production induced by PAF and PMA in murine resident PMΦ --- p.104 / Chapter CHAPTER 4 --- DISCUSSIONS / Chapter 4.1 --- PAF RECEPTOR ON PERITONEAL MACROPHAGES --- p.125 / Chapter 4.1.1 --- [3H]-PAF binding to peritoneal macrophages --- p.105 / Chapter 4.1.2 --- Expression of PAF receptor on Balb/c mice peritoneal macrophages --- p.107 / Chapter 4.2 --- SUPEROXIDE ANION PRODUCTION IN PERITONEAL MACROPHAGES --- p.108 / Chapter 4.3 --- PAF RECEPTOR AND POLYPHOSPHATIDYLINOSITOL SYSTEM IN PERITONEAL MACROPHAGES --- p.109 / Chapter CHAPTER 5 --- CONCLUSIONS --- p.112 / REFERENCES --- p.115

The self-assembly of amyloidogenic proteins to form cytotoxic species that give rise to brain deterioration underlies numerous neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. Increasing evidence indicates that it is the rare, low-molecular-weight species (oligomers) rather than the more abundant high-molecular-weight fibrils of certain proteins that are the most cytotoxic in several neurodegenerative diseases. However, these species have proven difficult to study using traditional methods due to their transient nature and the heterogeneity of aggregation mixtures. In this thesis, I describe my work to develop advanced methods where I combine single-molecule and ensemble fluorescence techniques with microfluidic strategies to enable the study of protein aggregation, spanning small, transient oligomers to large, insoluble aggregates. In Chapter 1 I give an overview of the biological context and relevance of this work, including the background of neurodegenerative disease, amyloidogenic aggregation and key proteins involved. I then briefly review fluorescence microscopy techniques and the field of microfluidics. In Chapter 2 I describe how complex microfluidics can be integrated with single-molecule confocal techniques to provide a highly sensitive method to continuously probe protein aggregation in vitro. I show, for the first time, that the dilution of aggregating mixtures may be automated, by up to five orders of magnitude, down to the picomolar concentrations suitable for single-molecule measurements. By incorporating this microfluidic dilution device I greatly improve the temporal resolution of the technique and facilitate the observation of more transient species through the ability to rapidly dilute and take fluorescence measurements of samples. In Chapter 3 I overcome the need for in situ labels to monitor amyloidogenic aggregation using single-molecule confocal microscopy. I describe my work to adapt the single-molecule confocal technique to achieve the ultrasensitive detection of individual aggregate species under flow without covalently-attached labels. I have demonstrated the ability of this new method to monitor the aggregation of label-free amyloidogenic proteins using extrinsic labels ex-aggregation, opening the way for biological samples to be probed in a high-throughput manner. In Chapter 4 I describe my work to combine the high precision of confocal microscopy with a microfluidic device developed to directly characterise the sizes and interactions of biomolecules in the continuous phase. By monitoring the spatial and temporal mass transport on the micron scale, the diffusion coefficient, and thus hydrodynamic radius, of species may be determined. The technique delivers much greater sensitivity for size quantification, allowing scarce and other challenging samples to be characterised, and provides significant steps towards accurate sizing for single-molecule aggregation experiments under flow. In Chapter 5 I describe my work to determine the microscopic driving force for the spatial propagation of amyloid-beta. The epifluorescence instrument I built has enabled the proliferation of aggregate species to be monitored over a macro distance on a timescale of minutes. This has greatly improved the scope of the experimental data attained, which will be used in conjunction with Monte Carlo simulations to deliver a model for the propagation of amyloid-beta in vitro. Together this thesis represents my work developing the above novel fluorescence techniques to improve their temporal and size resolution, sensitivity and adaptability to study highly complex and fundamental protein aggregation linked to neurodegenerative disease.

Protein deposition in the form of amyloid fibrils is the hallmark of more than 40 human pathologies, including Alzheimer's disease (AD) and Parkinson's disease (PD). Misfolded protein oligomers formed as intermediates during the aggregation process have been strongly implicated in the onset and progression of these diseases. In this thesis, I describe our efforts to uncover molecular agents that can reduce the toxicity caused by protein aggregation via targeting the generation, the physiochemical properties or the membrane affinity of oligomeric species. We employed an integrative approach combining in vitro techniques, including chemical kinetics, atomic force microscopy, and biophysical measurements, and in vivo methods, including neuroblastoma cells and C. elegans models of AD and PD, to identify a range of small molecules and antibodies that can suppress the toxicity related to protein aggregation through a variety of mechanisms. In Chapter 3, we show that the deleterious effects of protein aggregation can be suppressed in AD and PD worms by interfering with the aggregation rates of the amyloid-β peptide (Aβ) and the α-synuclein protein (αS). In Chapter 4, we resolve the mechanism of action for a molecule that enhances the rate of Aβ42 aggregation in AD worms with the result that toxicity is reduced, and find that it potentiates the secondary nucleation microscopic step in vitro. In Chapter 5, we characterize molecules and antibodies that modify the physiochemical properties and self-association of oligomers comprised of several proteins into clusters with reduced diffusibility. In Chapter 6, we classify a family of molecules that protect the cell by displacing several types of oligomeric species from the membrane through a generic mechanism. These results demonstrate strategies by which one can target the aggregation process to alter its resulting toxicity, provide insight into modifying the properties of the most deleterious species associated with protein aggregation and suggest that the protection of the cell from the oligomer-induced cytotoxicity associated with numerous protein misfolding diseases is a promising strategy to combat protein misfolding diseases.

abstract: Foodways in societies at every social scale are linked in complex ways to processes of social change. This dissertation explores the interrelationship between foodways and processes of rapid social transformation. Drawing on a wide range of archaeological and ethnographic data from the Cibola region, I examine the role of foodways in processes of population aggregation and community formation and address how changes in the scale and diversity of social life interacted with the scale and organization of food production and consumption practices. To address the interrelationships between foodways and social transformations, I employ a conceptual framework focused on two social dimensions of food: cuisine and commensality. This study comparatively examines cuisine and commensality through time by investigating a range of interrelated food activities including: food production, storage, preparation, cooking, consumption and discard. While settlement patterns and other more obvious manifestations of aggregation have been studied frequently, by examining foodways during periods of aggregation and social reorganization this study provides new insights into the micro-scalar processes of social transformation, cuisine change, and economic intensification associated with increases in settlement size, density, and social diversity. I document how food production and preparation intensified in conjunction with increases in the size of settlements and the scale of communal commensal events. I argue that foodways were a critical aspect of the social work of establishing and maintaining large, dense communities in the 13th and 14th centuries. At the same time, widespread changes in commensal practices placed a larger burden on household surplus and labor and women were likely the most affected as maize flatbreads and other foods made with finely ground flour were adopted and became central to cuisine. As such, this study provides insights into how rapid social transformations in the late 13th and 14th centuries were experienced differently by individuals, particularly along gendered lines. Studies of foodways, and specifically the social dimensions of food, offer a promising and often underutilized source of information about past processes of population aggregation, social integration, and transformations in the political economies of small-scale societies the past. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2019

Core-shell nanohybrids have wide applications in pollutant degradation. In this study, core-shell nanohybrid was formed through heteroaggregation between neutral nanoparticles (i.e., hematite nanoparticles or HemNPs) and charged nanoparticles (i.e., carboxylated polystyrene nanoparticles or PSNPs). In the dispersant solution of 1 mM NaCl at pH 6.3, HemNPs were neutral and underwent favorable homoaggregation, whereas PSNPs were negatively charged and underwent no homoaggregation. When the two types of particles were mixed, homoaggregation of HemNPs and heteroaggregation between HemNPs and PSNPs took place simultaneously, forming HemNPs-PSNPs heteroaggregates. The transmission electron microscopy images of heteroaggregates show that HemNPs and PSNPs formed core-shell structure in which HemNPs were the cores and PSNPs were the shells. The size of the core-shell nanohybrids can be controlled by varying the concentration ratio of HemNPs to PSNPs. The increase of the size of charged nanoparticles resulted in larger nanohybrids. This new method has lower energy footprint than existing ones. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

In 1745 a Scotch Benedictine monk Andrew Gordon discovered Contact Charge Electrophoresis (CCEP) which remained in dormant state for centuries until gaining renewed prominence in the field of particle manipulation and actuation. Contact Charge Electrophoresis (CCEP) refers to the continuous to and fro motion of a conductive object between two electrodes subject to an applied voltage. The continuous motion of the conductive particle and the low power requirement provide an attractive alternative to traditional methods for particle manipulation techniques such as dielectrophoresis. Recent efforts to understand and apply CCEP have focused on the motion of single particles and we present dynamics of multiple conductive particles dispersed in non-conducting media that utilize CCEP to perform tasks like pumping and cargo transport operations as well as multiparticle clusters capable of tailored trajectories. Chapters 1 provides motivation for this work and background on CCEP. Providing brief details on development of microfluidic devices and modeling that are covered in more details in subsequent chapters. It also focuses on the historical aspect of CCEP, relevant background, mechanism, physics, application strategies in literature, strategies developed for single particle systems and possible extension to multiparticle systems. Chapters 2 and 3 talk about the dynamics and modeling of multiple conductive particles both in dispersion and aggregates/clusters powered by CCEP. In Chapter 2, we propose a new hybrid approach based on image-based method proposed earlier by Bonnecaze[18] for modeling CCEP. It covers challenges to modeling a multiple particle system in confinement, dynamics of chain formation and dynamics of cluster comprising conductive and non-conductive particles between two electrodes. While Chapter 3 focuses on details of methods and techniques used in development of the simulation for dispersion of conductive particles in confinement. Here we also illustrate variation of conductivity for complete range of electrode separation with varying volume fraction. Chapter 4 expands on multiple particle CCEP and shows that when we physically constrain particle trajectories to parallel tracks between the electrodes, the traveling waves of mechanical actuation can be realized in linear arrays of electromechanical oscillators that move and interact via electrostatic forces. Conductive spheres oscillate between biased electrodes through cycles of contact charging and electrostatic actuation. The combination of repulsive interactions among the particles and spatial gradients in their natural frequencies lead to phase locked states characterized by gradients in the oscillation phase. The frequency and wavelength of these traveling waves can be specified independently by varying the applied voltage and the electrode separation. We demonstrate how traveling wave synchronization can enable the directed transport of material cargo. Our results suggests that simple energy inputs can power complex patterns of mechanical actuation with potential opportunities for soft robotics and colloidal machines. Chapter 5 systematically investigate the dynamics of cluster comprising multiple spherical conductive particles driven via contact charge electrophoresis (CCEP). We are specifically interested in understanding dynamics of closed packed cluster of particles with both conductive and non-conductive particles in three dimensions(3D). Finally, Chapter 6 summarizes new ideas and proposes possible applications for multiple particle Contact charge electrophoresis motivated by this dissertation.

During the 1990s a large-scale study of Port Phillip Bay, Australia, was undertaken by the CSIRO (the Commonwealth Scientific and Industrial Research Organisation, Australia's national research body). A major outcome of the study was a complex ecosystem model intended to provide scientific input into management decisions concerning the nutrient load to the bay. However, its development was costly and time-consuming. Given this effort, it is natural to seek smaller models (reduced models) that reproduce the performance measures of the large model (the full model) that are of interest to decision makers. This thesis is concerned with identifying such models. More generally, this thesis is concerned with developing methods for identifying these smaller models. Several methods are developed for this purpose, each simplifying the full model in different ways. In particular, methods are proposed for aggregating state variables, setting state variables to constants, simplifying links in the ecological network, and eliminating rates from the full model. Moreover, the methods can be implemented automatically, so that they are transferable to other ecological modelling situations, and so that the reduced models are obtained objectively. In the case of the Port Phillip Bay model, significant reduction in model complexity is possible even when estimates of all the performance measures are of interest. Thus, this model is unnecessarily complex. Furthermore, the most significant reductions in complexity occur when the methods are combined. With this in mind, a procedure for combining the methods is proposed that can be implemented for any ecological model with a large number of components. Aside from generating reduced models, the process of applying the methods reveals insights into the mechanisms built into the system. Such insights highlight the extent to which the model simplification process can be applied. Given the effectiveness of the model simplification process developed here, it is concluded that this process should be more routinely applied to large ecosystem models. In some cases, the full sequence of methods might prove too computationally expensive to justify its purpose. However, it is shown that even the application of a subset of the methods can yield both simpler models and insight into the structure and behaviour of the system being modelled.

In this thesis, we propose mechanisms to extend the lifetime of wireless sensor networks. In-network data aggregation is considered on both tree-based and flow-based routing protocols during the process of data collection to reduce redundant transmissions. In the flow-based data collection design, we introduce the concept of flow loss multiplier to express the impact of data aggregation over correlated data. The application has the freedom to set the flow loss multiplier to reflect its specific knowledge of correlation. We also introduce traffic balancing as a complementary technique to data aggregation. It helps avoid exhausting the energy of any sensor node while leaving large amounts of energy at other nodes. In tree-based data collection schemes, we adjust the tree structure judiciously to balance energy consumption before any node's failure due to total residual energy depletion. In flow-based schemes, after aggregation, data flows are split and the fragments are spread to increase network lifetime. We investigate the impact of performing greedily data aggregation at the "best" aggregation site regardless of its location, the results of our analysis show that only applying 2-way data aggregation may limit the ability to explore more complex aggregation possibilities. To address this problem, we propose an aggressive data aggregation for a specified application, contour map reconstruction. Based on the simulation results, our aggregation scheme is shown to be able to eliminate large volume of contour data and retain satisfying data accuracy.

This thesis presents a methodology for data aggregation for capacity management. It is assumed that there are a very large number of products manufactured in a company and that every product is stored in the database with its standard unit per hour and attributes that uniquely specify each product. The methodology aggregates products into families based on the standard units-per-hour and finds a subset of attributes that unambiguously identifies each family. Data reduction and classification are achieved using well-known multivariate statistical techniques such as cluster analysis, variable selection and discriminant analysis. The experimental results suggest that the efficacy of the proposed methodology is good in terms of data reduction.