Abstract This study utilized normal and defective epithelial cell cultures and epidermal skin samples to examine intra- and intercellular calcium signaling. The main interests of this thesis were Hailey-Hailey disease (HHD), Darier disease (DD), neurofibromatosis 1 (NF1) and transitional cell carcinoma (TCC). HHD and DD diseases are rare autosomal dominant skin disorders characterized by dissociation of epidermal keratinocytes (acantholysis) at the suprabasal layer of the epidermis. HHD and DD diseases are caused by mutations in the genes encoding the calcium pumps in the Golgi apparatus (hSPCA1) and endoplasmic reticulum (SERCA2b), respectively. Due to these mutations calcium uptake into the Golgi apparatus or ER is diminished, which is believed to cause abnormal cell junction protein processing and dissociation of keratinocytes. This study utilized electron probe microanalysis (EPMA) and demonstrated for the first time that lesional areas of HHD and DD and non-lesional areas of DD epidermis display abnormally low calcium content in the basal cell layer. Furthermore, ATP mediated calcium signaling was impaired in cultured HHD and DD keratinocytes and epidermal ATP receptor localization was disrupted. In conclusion, these results suggest that the low calcium content in the basal cell layer is the reason for suprabasal ruptures in HHD but not necessarily in DD lesions, and that abnormal ATP receptor localization contributes to the calcium signaling defects. NF1 deficient keratinocytes display abnormally low resting cytosolic calcium levels and it has been suggested that the calcium concentration in the lumen of the endoplasmic reticulum is decreased. This study demonstrated that NF1 keratinocytes rely mostly on ATP mediated calcium signaling while normal keratinocytes rely mostly on gap junctional intercellular communication (GJIC). Studies with TCC cells have demonstrated that gap junctions participate in intercellular calcium wave propagation. This thesis demonstrated that the ATP mediated pathway was also operational in calcium wave propagation in normal uroepithelial and TCC cell cultures. Furthermore, impaired calcium wave propagation in the TCC cell culture could be improved through PKC α/βI –isoenzyme inhibition with Gö6976. Gö6976 treatment increased connexin 26 clustering at plasma membrane but did not alter expression level of the protein. This thesis contains a wide repertoire of calcium detection techniques including a new cutting-edge technology for elemental calcium detection of epidermal samples. These techniques can be used for molecular specific analysis of calcium signaling in epithelial cells.

Microstructure and mechanical properties of AZ61 magnesium alloy in cast condition and after solution annealing were compared. The compare of mechanical properties of alloy, their hardness and microanalysis of occurring phases are included in this work. For compare has been used a light microscopy, tensile test, hardness measurements and scanning electron microscopy.

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No / Two routine consultations in primary care diabetes clinics are compared using extracts from video recordings of interactions between nurses and patients. The consultations were chosen to present different styles of interaction, in which the nurse's gaze was either primarily toward the computer screen or directed more toward the patient. Using conversation analysis, the ways in which nurses shift both gaze and body orientation between the computer screen and patient to influence the style, pace, content, and structure of the consultation were investigated. By examining the effects of different levels of engagement between the electronic medical record and the embodied patient in the consultation room, we argue for the need to consider the contingent nature of the interface of technology and the person in the consultation. Policy initiatives designed to deliver what is considered best-evidenced practice are modified in the micro context of the interactions of the consultation.

The pursuit of high quality, large area graphene has been a major research focus of contemporary materials science research, in the wake of the discovery of the multitude of exceptional properties exhibited by the material. The DPhil project was undertaken with the objective of developing an understanding of the growth of large graphene sheets by chemical vapour deposition (CVD), and also in the subsequent characterisation of their material properties. By conducting atmospheric pressure CVD growth at high methane flow rates, it was found that few-layered graphene (FLG) could be deposited on a copper catalyst. It is demonstrated that the self-limiting property of a copper catalyst is not universal to all deposition conditions, and shown that FLG grows in a terrace-like configuration. In depth transmission electron microscopy (TEM) studies were carried out on FLG. By selective image reconstruction from the inverse power spectrum of the TEM images, it was possible to elucidate the inter-grain connectivity of few-layer graphenes. It was determined that there were two possible inter-grain configurations possible; specifically an overlap of graphene layers or a discrete atomic bonding edge. The perturbation of the few-layer structure when subject to an out of plane distortion was found to incur a shift in the conventional AB-Bernal stacking of FLG. By utilising the aberration corrected TEM (AC-TEM) at Oxford it was possible to resolve atomic detail in CVD synthesised monolayer films, including atomic bond rotations and vacancies. The use of a high current density at low accelerating voltage (80 kV) was demonstrated to allow for the controlled defect creation in graphene sheets. This permitted the creation of monovacancies and iron doped vacancy complexes suitable for further study. The behaviour of these two defect types under electron beam irradiation was subsequently studied.

This thesis describes an investigation into silk spinning, with the objective of producing high performance silk fibres in the laboratory using a novel spinning device based upon observations on natural spinning glands and processes. After an in-depth literature review the work is reported in two sections: natural and artificial spinning. The literature provides fragmented data on different aspects of natural silk production, and artificial spinning has not yet reproduced fibres with the properties of native silk fibres, despite unfounded claims of biomimetic spinning. The first half of the thesis looks at natural silk spinning. The work started with a general study of the morphology of spider and silkworm spinning ducts: First, how the silk fibre develops as the dope flows through the gland; and second the relationship between silk fibre properties and both gland morphology and spinning speed. More detailed studies using histochemical and spectroscopic investigations showed that the silk ducts of the spider Nephila edulis and the silkworm Bombyx mori both contain β-chitin, despite an evolutionarily distant common ancestor. Finally, observations showed that the duct of N. edulis consists of alternating nanoporous discs, and FEA modelling indicated that the duct is optimised for mechanical integrity and permeability. The second half of the thesis describes the development of a spinning device that uses natural silk dope mainly taken from B. mori as feedstock. It begins with a description of the gradual development of the engineering aspects of the spinning device, to meet challenges raised during the spinning investigation. The development of a centrifugal capillary rheometer, for practical quantitative insights into rheological processes is then presented. Finally the spinning investigation is reported: first, the screening of spinning in glass capillaries based upon natural gland dimensions and flow rates, which have been shown to induce fibrillation in silk dope in a rheometer, and also included initiation of instability through heat applied along the capillary; second, the final spinning evaluation, using lessons learned from all the screening trials throughout the project, but also including a key development of a hydrophobic coating on the capillary tip to inhibit droplet formation and massively increase the process stability and ease of fibre production. The main conclusions from this work are that good silk fibre cannot be spun by flow shear stress alone; and, that heat instability induces indiscriminate gelation of the silk, whose disordered molecular structure gives poor silk fibre properties. The body of work behind these conclusions provides fundamental background information and new insights that will contribute to the next stages of development of artificial silk spinning, from obtaining a better understanding of the biology of natural spinning glands to the engineering difficulties of implementing the bioinspired principles.

The ability of RNA bases to self-assemble into larger structures is an important research area relevant to the origins of life. In the RNA helix the bases are arranged on a sugar-phosphate carcass but it has been suggested that the initial ordering could form on a flat surface. This thesis is an attempt to establish experimentally whether the complementary RNA bases, adenine and uracil, have the ability to self-assemble into large ordered structures when adsorbed on metal and mineral surfaces. The Au (111) surface was chosen as a preferred substrate as it is flat, relatively free of defects, chemically inert and reconstructs in a characteristic pattern of corrugation lines, which provide a reference for crystallographic directions. Six of the molecular phases shown were observed for the first time with molecular resolution and the possible two-dimensional arrangements of adenine and uracil molecules for these phases are proposed. The pure adenine and pure uracil structures have chiral unit cells and in the case of pure uracil alternating monochiral domains within the polychiral islands are created. Well-ordered intricate uracil-adenine bimolecular networks were also observed. The self-assembly of both uracil and adenine appears to be weakly influenced by the surface crystallography. The (100) surface of the mineral pyrite (FeS₂) was chosen as the alternative substrate as it is the most common face that occurs naturally in pyrite crystals. The experiments show the formation of small adenine and uracil crystals at the terrace edges. Neither uracil nor adenine were observed to form a monolayer on the surface of the terraces. The results of the experiments described in this thesis are very interesting in terms of establishing the possible mechanisms for creating regular chiral molecular networks and provide a useful insight into the role of surfaces in the processes of self-assembly of RNA bases.

Microscopic beams of penetrating synchrotron radiation provide a unique tool for the analysis of material structure and deformation. This thesis describes my contributions to the development of new synchrotron X-ray micro-beam diffraction experimental techniques and data interpretation, and the use of experimental results for the validation of material deformation models. To study deeply buried material volumes in thick samples, the micro-beam Laue technique was extended to higher photon energies. Through-thickness resolution was achieved either by a wire scanning approach similar to Differential Aperture X-ray Microscopy (DAXM), or by applying tomographic reconstruction principles to grain-specific Laue pattern intensity. Both techniques gave promising first results. For reliable micro-beam Laue diffraction measurements of elastic strains in individual grains of a polycrystal, understanding of the error sources is vital. A novel simulation-based error analysis framework allowed the assessment of individual contributions to the total measurement error. This provides a rational basis for the further improvement of experimental setups. For direct comparison of experimental measurements and dislocation dynamics simulations, diffraction post-processing of dislocation models in two and three dimensions was developed. Simulated diffraction patterns of two-dimensional dislocation cell/wall type structures captured correctly some of the features observed experimentally in reciprocal space maps of a large-grained, lightly deformed aluminium alloy sample. Crystal lattice rotations computed from three-dimensional dislocation dynamics simulations of a Frank-Read source showed anisotropic orientation spread similar to that observed in micro-beam Laue experiments. For the experimental study of crystal lattice distortion, a novel technique was proposed that combines micro-beam Laue diffraction with scanning white-beam topography. Diffraction topography allows the study of lattice rotation at scales smaller than the scanning beam size. The new technique makes it possible to apply classical topography methods to deformed samples.

The initiation and high resolution control of surface confined chemical reactions would be both beneficial for nanofabrication and fundamentally interesting. In this work, spatially controlled scanning probe directed organometallic coupling, patterned functional protein immobilisation and highly localised reversible redox reactions on SAMs were investigated. Catalytically active palladium nanoparticles were mounted on a scanning probe and an appropriate reagent SAM was scanned in a reagent solution. This instigated a spatially resolved organometallic coupling reaction between the solution and SAM-phase reagents. Within this catalytic nanolithography a spatial resolution of ~10nm is possible, equating to zeptomole-scale reaction. The methodology was applied to reactions such as Sonogashira coupling and local oligo(phenylene vinylene) synthesis. By altering the experimental protocols, relating probe scan velocity to reaction yield and characterising the nanopattern, a PVP matrix model describing a proposed mechanism of catalytic nanolithography, was presented. Though ultimately limited by probe deactivation, calculations indicated that activity per immobilised nanoparticle is very high in this configuration. For biopatterning, surface nanopatterns defined by carboxylic functionality were generated from methyl-terminated SAMs by local anodic oxidation (LAO) initiated by a conductive AFM probe. By employing suitable linker compounds, avidin and Stefin-A quadruple Mutant (SQM) receptive peptide aptamers were patterned at sub-100nm resolution. The multiplexed sensing capability of an SQM array was demonstrated by reacting generated patterns with single or a mixture of multiple antibodies. The reversible redox conversion and switching of reactivity of hydroquinone-terminated SAMs was electrochemically demonstrated prior to an application in redox nanolithography. In this methodology, spatially controlled probe-induced in situ "writing" and "erasing" based on reversible redox conversion were conducted on hydroquinone terminated SAM. In combination with dip-pen nanolithography, a novel method of redox electro-pen nanolithography was designed and the method’s application for lithography was examined.

Ferritic ODS steels show improved high temperature strength and irradiation tolerance compared with conventional ferritic steels, and are one of the key potential materials for fusion blanket structural applications. The processing of ODS steels is critical to their subsequent performance; however knowledge of the optimum processing approaches for these alloys is not complete. The microstructural evolution of ODS steels containing Y₂O₃ and other additions during manufacture has been investigated and the processing conditions optimised based on microstructural and mechanical investigations. Ferritic powders with Y₂O₃ and other additions were investigated, primarily using analysis on the micro- and nano-scale, with an emphasis on identifying the requirements for homogenization of the Y within the steel matrix. The Y₂O₃ dispersion and subsequent development of the nano-precipitates during thermal treatment was investigated using in-situ neutron diffraction. The nano-precipitates were resolved at approximately 900◦C after 1hr, with coarsening and/or re-precipitation progressively increasing at higher temperatures. A significantly increased number density of nano-precipitates (∼2x10²³m−3 to ∼7x10²³m−3) was established by hot isostatically pressing an Fe-14Cr-3W-0.2Ti0.25Y₂O₃ alloy at 950◦C compared with more traditional temperatures at 1150◦C, attributed to the increased coarsening and/or re-precipitation of the nano-precipitates at the higher temperatures. The influence of the mechanical alloy (MA)ing conditions on bulk mechanical properties was investigated using four point bend. The highest fracture toughness of ∼55MN/m^3/2 and ultimate strength of ∼1450MPa was achieved under conditions that minimised the mechanical alloying time and increased the average final size of the powders. An Fe-14Cr-3W-0.2Ti-0.25Y₂O₃ (wt%) ODS alloy manufactured under optimised conditions showed a bi-modal grain structure size distribution and had a comparatively high yield strength of >1200MPa at 20◦C and >330MPa at 700◦C. The grain structure and high yield strength were attributed to the random distribution of 25nm radius of gyration (R_g) Y, Ti and O rich nano-precipitates randomly dispersed throughout the alloy. Long term thermal ageing (750hr at 1000◦C) reduced the room temperature yield strength and increased the proportion of larger grains in the bi-modal distribution, but high temperature yield strength was remarkably stable.