Der Mechanismus der Miniemulsionsbildung bzw. polymerisation wird eingehend untersucht. Dabei werden Faktoren, wie die Tensidmenge, Ultraschalldauer und die Teilchengröße untersucht. Besonders werden auch noch Aspekte wie Stabilität der Emulsion und Kinetik während der Polymerisation untersucht. / The mechanism of the formation and polymerisation of the miniemulsion respectively is thoroughly investigated. Parameters such as surfactant amount, duration of ultra sound and particle size are surveyed. Special emphasize is given to the aspects of stability of the emulsion and the kinetic of the polymerisation. <br><br> ---- <br><br>Anmerkung:<br> Die Autorin wurde 2001 mit dem Publikationspreis des Leibniz-Kollegs Potsdam für Nachwuchswissenschaftler/innen in den Naturwissenschaften ausgezeichnet.

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published_or_final_version / Public Administration / Master / Master of Public Administration

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Dementia, a stepwise deterioration of cognitive function, affects over 700,000 people in the UK, resulting in over 60,000 deaths and a cost of over £1.7 billion each year. It is believed to have a combination of vascular and degenerative origins and to have correlations with localised lesions, or infarctions, in the brains of affected patients. Mini-strokes are one of the causes for this disease as the presence of ischemia is highly related to the risk factors for dysfunction of the neurovascular unit. The underlying interacting mechanisms are, however, often very complex and they remain largely poorly understood. The cerebral microvascular bed is highly irregular and localised variations in its structure are large. To capture these variations, statistical algorithms are required, rather than large volumes of expensive experimental data. Therefore, accurate modelling of blood flow and oxygen transport at the microvascular level is important in improving our understanding of the structure and function of the cerebral vasculature and hence of brain diseases. A novel algorithm is proposed here to create artificial microvascular networks that match quantitatively experimental data previously obtained in human brain tissue. Blood flow and oxygen transport in the network and the tissue are analysed through both discretised and continuum transport models. By disabling flow sources, ischemic events can be simulated. Using multiple networks, the influence of individual network structures on the response to ischemia is analysed. The relationship between the discretised and continuum formulations of the model is quantified, providing a means for scaling up the model over multi length scales. Finally, the phenomenon of microvessel collapse under ischemic conditions is examined and it is shown that this is fundamentally dependent upon the variability found at the network level, since it cannot be modelled by a continuum model. An initial infarction is also found to facilitate the occurrence of collapse events for most networks.

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There are clear indications that over the coming years, as more people live longer with life limiting illnesses an increasing amount of support for carers of service users with palliative care needs will be required. Respite care is often described in UK policy and guidance as a key need in providing this support and yet little is known about it for patients with life limiting illnesses and there is a lack of research to support its efficacy. The purpose of this research was therefore to establish whether respite care addresses the needs of palliative care service users and carers. The approach was qualitative and the methodology was interpretive. The method used was constructivist Grounded Theory. This provided high compatibility with the theoretical underpinnings which were learning from the experiences of service users and carers, embracing the principles of critical practise and learning through relational endeavour. Data collection was carried out by unstructured informal interview with three couples and two bereaved carers who had experienced hospice respite care. The participants were interviewed on two occasions and social network circle activity was undertaken as part of theoretical sampling. Findings showed that respite care is valued by palliative care service users and carers although there are some fundamental tensions in service models which limit its potential. A theory of vulnerability and resilience was developed which accommodated issues of needs and acceptance, choice and risk, loss and gains. A reframing of respite care as an empathic response within a new palliative care approach is proposed. Within this the centrality of the relationship is reinforced and the need for support over a potentially long and more uncertain illness trajectory is acknowledged. The articulation of respite care needs and the insights gained in this study have the potential to influence practice and provide a platform for innovative service development and improvement.

Poor quality and unrefreshing sleep is one of the most common symptom complaints in Chronic Fatigue Syndrome (CFS). Despite this, the links between sleep dysfunction and CFS are not well understood, and there has been an absence of good quality research into the nature of sleep problems in CFS, which also lack consistency in the data reported. However, it remains plausible that sleep problems may help to maintain and exacerbate other existing symptoms. Given the dispute in models ranging from the biological to the psychological, competing to explain symptomology, it is a critical time by which we try to understand the relationship between poor sleep, fatigue, endocrine activity and CFS, in an attempt to shortcircuit this debate. With an aim to redress this, this thesis intended to examine the role of sleep from several angles, utilizing a range of assessment methods; Study 1 addressed the lack of in depth qualitative interview studies, to understand the extent to which sleep, its management and problems, are linked to the lived experience of CFS, and how it interacts with other symptoms (chapter 3). Patient narratives demonstrated that sleep disturbances experienced were highly unpredictable and variable over time, but played a key role in symptom maintenance; Study 2 examined self-reported sleep (via sleep diaries) in CFS patients, exploring whether sleep quality and daytime napping had an impact on daytime fatigue, sleepiness and cognitive functioning (key dimensions of the illness experience) (chapter 4). The results were highly variable but indicated that afternoon-evening napping was associated with greater impairment in daytime cognitive functioning in CFS patients. It was also evident that CFS patients with longer wake time and a shorter diagnosis had more severe fatigue; Study 3 explored the possibility that sleep problems in this population are not homogeneous and revealed four sleep-specific phenotypes to exist, which are amenable to different treatment approaches. The initial cross-sectional examination of single-night polysomnography (PSG) data identified 30% of the sample had a primary sleep disorder (PSD), which underscores the need to assess for PSDs in CFS populations (chapter 5); Study 4 was conducted to address the principle aim of this thesis; to determine the feasibility of a detailed, 3-night sleep assessment protocol in a small cohort of CFS patients. By utilising iv a range of methods including ambulatory PSG and a gold-standard protocol for sampling of diurnal salivary cortisol, the study piloted the most comprehensive assessment of sleep ever attempted in a CFS population. The findings established a successful protocol that was acceptable to patients (chapter 6), a key advancement in this field where effective and thorough sleep assessment is needed. Preliminary sleep data confirmed a notable variability of sleep problems to exist. Further, the temporal stability of sleep variables was established; sleep continuity (sleep duration, wake duration, sleep efficiency) and main architectural (sleep stages) parameters were consistent across two nights of assessment (chapter 7). The results presented in this thesis indicate that disturbed sleep is a major problem for patients with CFS, albeit highly variable between and within individuals. The identification of sleep phenotypes also confirms the heterogeneity of sleep in CFS. Interestingly, light sleep and arousability was a recurring sleep characteristic in patients that was mirrored by the studies presented throughout the thesis, highlighting a potential autonomic component. This should be a consideration for forthcoming work, along with the possibility that sleep disturbances may mediate the maintenance and exacerbation of symptoms, fuelling a reciprocal cycle that keeps the condition going. The preliminary findings presented throughout this trajectory of research will help to form the systematic development of a sleep characterisation and intervention programme. With this field moving towards more patient-centred medicine and tailored treatments, by combining data from the objective and subjective sleep measures, we aim to design a definitive multicentre study, using sleep-specific interventions, amenable to the four phenotypes identified. The long-term goal is to improve treatments that will enhance symptom management, which is crucial in this condition, at least until the CFS research understands the pathogenesis of this debilitating disease.

This research work covers the development of a novel compact model for a Floating Gate nMOSFET that will be added to the QUCS library. QUCS (Quite Universal Circuit Simulator) is a GPL simulation software package that was created in 2006 and is continuing to develop and evolve, and there is already a substantial library of components, devices and circuits. Fundamentally, a floating gate device is an analogue device, even though modern technology uses it mainly as a non-volatile memory element there are numerous uses for it as an analogue device. A study has been carried out with regards to the principles of the physical phenomenon of charge transfer through silicon dioxide to a floating gate. The study has concentrated on the physical properties of the fabricated device and the principles of charge transfer through an oxide layer by Fowler–Nordheim principles. The EKV2.6 MOSFET was used as the fundamental device for the model that has been adapted by the addition of the floating gate. An equivalent circuit of an FGMOSFET was developed and analysed theoretically. This was then formulated into the QUCs environment and created as a compact model. Simulations were carried out and the results analysed to compare with the theoretical expectations and previous research works. It is well documented that the creation of equivalent circuits for floating gate devices is complicated by the fact that the floating gate is isolated as a node and as such cannot be directly analysed by simulators. For the equivalent circuit created, circuit analysis was achieved by the introduction of high value resistances connected in parallel with the capacitive elements that are representative of the incursion of the floating gate that is intrinsic to a floating gate device. The resistance elements were of such value that the time constants were of the order of 10000s and did not interfere with the simulation. The equations from the analysis were formulated and the anticipated responses were shown. The analytical equations developed were then used within the QUCS environment with explicit use of EDDs(Equation Defined Devices) to create a novel model of a FGMOSFET. Simulations of the model created were carried out with a range of voltage pulses being applied to the tunnelling terminal to affect a charge transfer to the floating gate by means of Fowler-Nordheim principles. The changes of the charge stored on the floating gate were clearly shown by the measured anticipated associated shift in the Threshold voltage. Simulated results have been compared with previous research and development work and the new model is considered effective. Also because of the ability of the QUCS software to allow the variation of the multiplicity of the parameters associated with the fabrication process, it is considered to be adaptable to a range of modern floating gate device structures and materials.