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A mouse model was used to study the pathogenesis of systemic infection by the opportunistic pathogen <i>Candida albicans</i>. Using this model it was demonstrated that <i>C. albicans</i> yeast cells were more pathogenic for mice than hyphal forms. Polymorphonuclear leukocytes were shown to be important in resistance to systemic infection by <i>C. albicans</i>. Studies on conditions which promote germination of <i>C. albicans</i> yeasts showed that maximum numbers of yeast cells produced germ tubes when incubated in tissue culture media at 37°C, by 2 hours. A comparative ultrastructural examination of yeasts, germ tubes and hyphal forms demonstrated marked differences in the thickness and organisation of the cell walls between these forms. Furthermore, germination of <i>C. albicans</i> yeasts was shown to be accompanied by significant release of cell wall antigens. <i>In vitro</i> interactions between mouse polymorphonuclear leukocytes and <i>C. albicans</i> yeasts, germ tubes and hyphae in the absence of serum were examined. Mouse neutrophils were found to adhere readily to the surface of germ tubes and hyphae but not yeasts. This adherence resulted in damage of the fungus. Studies on the degradation of killed <i>C. albicans</i> yeasts following phagocytosis by murine macrophages <i>in vitro</i>, showed that progressive removal of yeast cell wall layers occurred. This was followed by dissolution of the cytoplasmic contents. During this process, cell wall and cytoplasmic antigens were released into the surrounding medium. An enzyme linked immunosorbent assay was developed to measure IgM, IgA and IgG class antibodies to <i>C. albicans</i> mannan and cytoplasmic antigens in patient's sera, and was shown to have diagnostic potential for candida infection. In particular, use of this assay to monitor the kinetics of antibody levels to these antigens was found to be of diagnostic value for immunocompromised patients at risk of candida infection. Finally a number of monoclonal antibodies were produced to <i>C. albicans</i> cytoplasmic proteins and have been partially characterised.

The thesis examines the perceptions and treatment of Gypsies in Britain during the early twentieth century. This enquiry touches upon a number of historically important themes and also has a contemporary relevance. Firstly it outlines the tradition of writing about the Gypsies which had developed over the previous two centuries and considers the treatment of the group in the work of early commentators. Secondly, it explores the nature of stereotypes of the Gypsies in early twentieth century society and considers the ways in which romantic and antipathetic images of the Gypsies could be crafted into a coherent rather than a contradictory body of thought by drawing on ideas of hierarchy and degeneration. Thirdly, it analyses responses to Gypsies from across sedentary society. The focus here is on the treatment of the group by legislators, local authorities, missionaries and scholars. Finally, it argues that responses to the group must be considered as of part of the age-old tradition of hostility towards nomadism in Europe. The examination of the treatment of the Gypsies in Britain reveals significant differences with their treatment elsewhere in Europe during the same period. Although there is evidence of antipathy towards the Gypsies at every level of British society there is a relative absence of institutionalised intolerance. However, it is evident that the ideas which were used to justify such treatment of the Gypsies elsewhere in Europe were also present in Britain, and that the treatment of immigrant Gypsies by the British state, in particular, reveals that it was not immune from antipathy.

This thesis describes a series of studies to investigate the predator-prey relationships between the Goosander Mergus merganser, a fish-eating duck, and populations of game fish in northern Britain. The distribution and numbers of birds during the breeding season, in northern England and Scotland, were investigated and variations in density, between and within rivers, studied. Relationships between densities in spring and summer survey periods were also investigated. Possible biases in survey data are discussed. Studies of the growth of ducklings reared in captivity allowed estimates to be made of food and energy requirements from hatching up to approximately the time of fledging, at c70 days. Seasonal changes in the body mass and body condition of adult and immature Goosanders were investigated and daily and seasonal food and energy requirements estimated. Time-budget data were collected to investigate how birds partitioned their time between various behaviours. Of particular concern was the temporal and spatial distribution of foraging activities between and within broad habitat types, viz. rivers, standing waters known to be roost sites, and non-roost standing waters. Feeding behaviour was also recorded. The species composition of the diet and the numbers of individual fish represented, were determined by the gut analysis of 54 birds received from various sources. Possible biases in this method are discussed. For salmonids, the size of individual prey items was investigated from regression equations of fork length on vertebrae length, based on a reference collection. Conflicting evidence of damage to fisheries from other studies chiefly in North America, is re-assessed in the light of current knowledge of the population dynamics of salmonids and of results presented here. The potential contribution of depredations by Goosanders to mortality at successive life stages of fish is considered.

The application of inductively-coupled plasma (ICP) spectrometry for the analysis of solutions and slurries is reviewed. The critical parameters which affect analytical performance are identified and methods for the optimisation of the ICP for such applications demonstrated. Particle size of the suspended sample is shown to be the most important factor in the analysis of slurry samples. It is demonstrated that only particles less than 8 um in diameter reach the plasma even when the maximal diameter injector tube (3 mm i.d.) is used. Accordingly various methods for the reduction of particle size have been investigated and milling shown to be the preferable approach. A low cost method using blown zirconia spheres in a screw-cap plastic bottle agitated on a flask shaker was developed. Using this method it proved possible to analyse a wide variety of solid samples using slurry atomisation using both ICP- atomic emission spectrometry (ICP-AES) and ICP-mass spectrometry (ICP-MS) with aqueous calibration. Results are presented for the elemental analysis of certified reference material (CRM) soils, catalyst samples, a zeolite, titanium dioxide, P.T.F.E. powder, and unfiltered natural waters by slurry atomisation ICP-AES. Comparison by other techniques showed excellent accuracy for major, minor and trace elements and equivalent precision to solution analysis. The CRM soils, catalysts and the zeolite were also analysed by ICP-MS using slurry atomisation with similar success and enhanced accuracy at the trace level. Aluminium proved to be an exception and generally low recoveries (80-90%) were observed for this element using slurry atomisation. Finally the uses of the simplex optimisation algorithm to improve analytical performance, particularly in ICP-AES, is discussed. A computer program to facilitate the use of simplex optimisation for a variety of instrumentation was written and its use in three different analytical techniques demonstrated. The necessary hardware and software modifications to a commercially available ICP spectrometer to enable automated simplex optimisation are described. The prospects for such intelligent self-optimising instrumentation are discussed as is the potential extension of the application of slurry analysis by ICP-AES and ICP-MS.

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This project aims to discover a new means of overcoming the drawbacks of traditional layer-by-layer dip coating through the use of polyelectrolyte complexes (PECs) and electrophoretic deposition. The layer-by-layer process, by which oppositely charged polyelectrolytes or other charged particle are alternately adsorbed onto a substrate to produce a thin film of precisely controllable thickness, is versatile and simple to implement but suffers from requiring numerous, long deposition steps to produce uniform micron thick films. PECs are small associations of oppositely charged polyelectrolytes that, when mixed in non-stoichiometric ratios, can form charged water- soluble particles. There is much still to be determined about the phase behavior of PECs. However, it has been shown that they can exist over a range of conditions. Electrophoretic deposition is a technique used in many commercial applications for the deposition of charged particles onto a conducting substrate. It has even been shown to enhance the deposition of polyelectrolyte single layers and multilayers. This study examines the phase behavior of PECs made of linear poly(ethyleneimine) (LPEI) and poly(acrylic acid) (PAA). PEC behavior is studied over a pH range of 4.0 to 6.0, with no salt added to the system. This study also reports the results of tests examining how soluble PECs responded to changes in pH and whether solid PECs could be made to dissolve through the addition of different salts. Light scattering is used to examine the particle size distribution and effective diameter of PECs in solution. This information is then used to electrophoretically deposit PECs with 10%, 30%, 70%, and 90% excess LPEI. Stylus profilometry is used to assess the thickness of deposited films. The results showing that PEC layers deposited under an applied voltage were 40% to 400% thicker than PECs deposited with no applied potential.