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The objective of this work is two-fold; investigation of the electrochemical and electrochemiluminescent (ECL) properties of near-infrared (NIR) quantum dots (QDs) in buffer and whole blood; and their subsequent incorporation into ECL biosensing systems with potential application in whole blood analysis. QDs exhibited size-dependent optical and electrochemical properties with the largest QDs demonstrating ECL emission in the NIR region (811 nm). This should improve light penetration through whole blood, a prediction that has not yet been investigated for the ECL process. NIR QDs were shown to be flexible ECL emitters and optimisation of system parameters was implemented to obtain maximum ECL performance. This was achieved using a QD-chitosan film on a glassy carbon electrode with potassium persulfate co-reactant in phosphate buffered saline at pH 7.4. Intense reductive and oxidative ECL signals were generated directly in whole blood, which was at least ten times more intense than t hat achieved using visible region emitting QDs. The response exhibited sensitivity to blood samples spiked with clinically relevant analytes, homocysteine and dopamine, establishing the viability of NIR ECL as a detection method from whole blood. To expand the integration of NIR QDs into biosensing systems, a selective biosensor for cholesterol was developed that exhibited good stability, specificity and a clinically relevant linear range (1-5 mM). Detection in human serum was possible, however, radical quenching in whole blood limited its use as a biosensor in this environment in its current form, demonstrating the complications that can arise with analysis from such a complex matrix. For that reason, an alternative biosensor design that used conditions optimised in earlier work was used to improve system sensitivity. Fabrication of an immunosensor for IgG resulted in an ECL signal that was detected in whole blood. Following significant development, it is envisaged such a system can form the basis of a new generation of NIR ECL biosensors capable of detection directly from whole blood.

Due to their disproportionate risk of tenancy non-sustainment there have been concerns raised for young people making a pathway out of homelessness into independent living. Despite these concerns, there has been limited research looking at how young people experience tenancy sustainment or where they move onto after terminating a tenancy. This thesis, drawing on Bourdieu’s (1990a) theory of practice, presents a reconceptualisation of tenancy sustainment as a practice of sustaining a tenancy. The theoretical-empirical analysis is based on data collected through longitudinal research involving two waves of semi- structured interviews with 25 young people, aged 16-25, who had recently made a pathway out of homelessness into their own independent tenancies. The interdependency between a tenant and their tenancy presented young people with pressures which they developed techniques of independent living in response to in order to sustain their tenancy and make it a home. Young people not only had a particular housing position of being a tenant, they held family and education-employment positions which took part in the formation and shaping of the pressures they experienced living independently. Tenancies were not seen as an end in themselves by young people who desired, through the experience of sustaining a tenancy, increasingly independent positions within their other social positions as well. An uneven process of actually existing neoliberalism across policy areas through its influence on young people’s constellation of interdependent relations also created a dissonance within the positions held by young people fostering social suffering. Young people ending a tenancy viewed this as a ‘step backwards’ when it meant decreasing independence such as a return to supported accommodation; ambivalence where it arose from the end of a relationship; and as a move forwards, or ‘getting on with life’, when making a youth transition and housing pathway towards establishing their own family household.

Epithelial cell-cell adhesion is mediated by tight junctions, adherens junctions and desmosomes. Epithelial cell-matrix adhesion is mediated by hemidesmosomes and focal contacts. These complexes exhibit great plasticity, and each contains molecular components which are able to participate in one or more of the other adhesive complexes. Focal adhesion kinase (FAK/pl25FAK) is a non-receptor tyrosine kinase which transduces signals from integrins at sites of focal contact to promote adhesion, spreading and migration. FAK possesses a central kinase domain which is flanked by large, non-catalytic, amino- and carboxy-terminal domains. Whereas the functions of the carboxy-terminal and kinase domains of FAK are well understood, the role of the amino-terminal domain remains unclear. FAK expression was examined in the human epithelial cell line, HEK 293. Amino-terminal FAK immunoreactivity was noted at sites of cell-cell contacts and in the nucleus, in contrast to carboxy-terminal immunoreactivity, which was largely cytoplasmic and perinuclear. Western blot analysis of endogenous FAK revealed expression of a presumptive proteolytic cleavage fragment corresponding to the amino- terminal domain. A series of FAK constructs was generated to test the hypothesis that the observed amino-terminal FAK localisation was due to this proteolytic fragment. Epitope- tagged Amino-Terminal FAK (ATF) constructs localised primarily at areas of cell-cell contact and in the nucleus in HEK 293 cells. This localisation was independent of Tyrosine 397, the major FAK autophosphorylation site. This sub-cellular distribution was confirmed in another epithelial cell line, MDCK, in which transiently transfected ATF constructs also localised primarily to the nucleus and at cell-cell contacts. HEK 293 cells were characterised with respect to expression of adhesive proteins, and ATF was found to co- localise with the tight junction protein occludin, with cortical actin and with junctional ?1 integrin. Immunoprecipitation data suggests that none of these proteins forms a precipitable complex with ATF. These findings indicate that the amino-terminal domain of FAK is capable of localising at epithelial cell-cell contacts and suggest a novel role for FAK in mediating cross-talk between focal contacts and cell-cell contacts through endogenously expressed amino-terminal FAK fragments.