This study was conducted to elucidate and to compare some factors which influence the host-seeking behaviour of adult female simuliids in two geographically isolated regions. Various observations and experiments were performed with the knowledge of a mechanism inherent in the feeding behaviour of simuliids. This approach has helped to clarify the orientation of simuliids to their hosts and has enhanced the understanding of the transmission of parasites by these flies. Further, it was found valuable to determine whether the behaviour state of simuliids influenced their reaction to visual stimuli. / Thesis / Master of Science (MSc)

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Call number: LD2668 .T4 1932 B41

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Systemic candidiasis is most commonly studied in animal models, particularly the murine intravenous (IV) challenge model, where infection with a virulent Candida albicans strain leads to increasing fungal kidney burdens and increasing pro-inflammatory cytokines in the kidneys. Based upon the finding that early renal levels of the chemokine KC correlate with infection outcome, a new in vitro model, utilising the murine renal M-1 cortical collecting duct epithelial cell line, was developed to evaluate virulence of C. albicans isolates and mutants, in attempts to reduce the number of mice used in C. albicans virulence studies, addressing the 3Rs. The epithelial cells were shown to respond only to live fungal cells, unlike immune cells, responding more robustly to hyphae rather than to cells growing as yeasts. We also demonstrate that non-albicans Candida species, which are attenuated in the mouse IV challenge model, are unable to elicit chemokine responses from mouse kidney epithelial cells, despite increasing the inoculums used. Renal epithelial cell responses observed in the new model reflect early events in the mouse model, with chemokines KC and MIP-2 produced in response to virulent C. albicans strains or mutants. This chemokine production correlates with C. albicans damage to epithelial cells. Some involvement of TLR4 signalling was demonstrated as blocking of TLR4 signalling reduced epithelial KC production, and it was demonstrated that the renal epithelial cells respond strongly to more complex glycan molecules. Using this new in vitro model we have confirmed that renal epithelial cells are able to discriminate between virulent and attenuated strains of C. albicans, allowing this model to be used as an initial screen for altered virulence and for investigating how renal epithelial cells detect the presence of pathogenic fungi.

Abstract This research work details a systematic study of the structure and function of supramolecular host-guest systems. Host-guest inclusion complexes were formed between β-Cyclodextrin (β-CD) and its copolymers (as hosts), with several types of guest molecules both in aqueous solution and the solid state. The research is divided into two themes; (1) structural characterization and dynamic properties of the inclusion compounds of β-CD with various guest systems in aqueous solution and the solid phase, and (2) heterogeneous adsorption and structural studies of β-CD based copolymers with various guest systems in aqueous solutions. The guest systems include alkyl and perfluoroalkyl carboxylates, perfluoroalkyl sulfonate, and p-nitrophenol (PNP) at variable experimental conditions. In the first theme (chapter 2-5), host-guest complexes in the solid state were prepared using dissolution and slow cool methods at variable host/guest mole ratios (i.e., 1:1 and 2:1). The complexes were further characterized using 19F/13C DP/MAS and CP/MAS solid-state NMR spectroscopy. The solution state complexes were prepared in D2O for structural characterization using 1H/19F NMR spectroscopy. The NMR studies were complemented using FT-IR, thermal analyses (DSC, and TGA), and powder X-ray diffraction (PXRD). Evidence for the formation of host-guest inclusion compounds (ICs) was provided using CP/MAS solids NMR spectroscopy and complexation-induced chemical shift (CIS) values of 1H/19F nuclei in aqueous solution. The β-CD/PFC ICs displayed variable guest geometry and hydration states as determined by the host-guest stoichiometry and the conformation of the guest. PFOA and SPFO form 1:1 and 2:1 ICs with β-CD, wherein the guest adopts a range of gauche and trans conformations, respectively. 1:1 host-guest complexes were concluded for short perfluorocarbon chains (i.e., PFBA) where the gauche conformation of the PFC guest in the bound state was favoured. In the second theme (chapters 6–8), β-CD based copolymers were used as host materials. The structural characterization of a soluble poly-CD material (known as HDI-1) revealed that the solution behaviour of such polymeric hosts are sensitive to the presence of guest compounds such as p-nitrophenol (PNP) (i.e. chemo-responsive), as well as temperature variations (i.e. thermo-responsive). The host-guest chemistry of the soluble poly-CD material, as studied by 2-D solution NMR and induced circular dichroism (ICD) spectroscopy, indicates that PNP was bound within the cavity sites of β-CD and the interstitial domains of the copolymer (cf. Scheme 1.6 and chapter 6). The observed responsive nature of such polymeric host materials to temperature variation and chemical potential resembles behaviour characteristic of ‘smart materials’. Herein, ‘smart materials’ refer to systems which are responsive to external stimuli (e.g. temperature and chemical). The adsorption properties of the soluble (HDI-1) and insoluble (HDI-3 and -6) poly-CD adsorbents with octyl and perfluorooctyl carboxylate and sulfonate anions were estimated using the Sips and BET models. The hydrocarbon (HC) and fluorocarbon (FC) anions form monolayer and multilayer structures at the surface of the polymeric adsorbents, respectively. The formation of layered structures was controlled by the relative hydrophobicity of the alkyl/perfluoroalkyl chains and their mutual miscibility with the adsorbent surface. Other factors include the inductive effects of the alkyl/perfluoroalkyl head groups and their interactions with aqueous solvent or dipolar domains of the adsorbent surface. The adsorbed species at the liquid-solid interface were characterized using FT-IR spectroscopy, thermal analyses, and contact angle.

The primary objective of this thesis is to develop a methodology for fast, yet accurate temperature estimation during design space exploration. Power and temperature of modern day systems have become important metrics in addition to performance. Static and dynamic power dissipation leads to an increase in temperature, which creates cooling and packaging issues. Furthermore, the transient thermal profile determines temperature gradients, hotspots and thermal cycles. Traditional solutions rely on cycle-accurate simulations of detailed micro-architectural structures and are slow. The thesis shows that the periodic power estimation is the key bottleneck in such approaches. It also demonstrates an approach (FastSpot) that integrates accurate thermal estimation into existing host-compiled simulations. The developed methodology can incorporate different sampling-based thermal models. It achieves a 32000x increase in simulation throughput for temperature trace generation, while incurring low measurement errors (0.06 K- transient,0.014 K- steady-state) compared to a cycle-accurate reference method. / text

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