Global ETD Search

21	Quantifying impaired metabolism following acute ischaemic stroke using chemical exchange saturation transfer magnetic resonance imaging Msayib, Yunus January 2017 (has links) In ischaemic stroke a disruption of cerebral blood flow leads to impaired metabolism and the formation of an ischaemic penumbra in which tissue at risk of infarction is sought for clinical intervention. In stroke trials, therapeutic intervention has largely been based on perfusion-weighted measures, but these have not been shown to be good predictors of tissue outcome. The aim of this thesis was to develop analysis techniques for magnetic resonance imaging (MRI) of chemical exchange saturation transfer (CEST) in order to quantify metabolic signals associated with tissue fate in patients with acute ischaemic stroke. This included addressing robustness for clinical application, and developing quantitative tools that allow exploration of the in-vivo complexity. Tissue-level analyses were performed on a dataset of 12 patients who had been admitted to the John Radcliffe Hospital in Oxford with acute ischaemic stroke and recruited into a clinical imaging study. Further characterisation of signals was performed on stroke models and tissue phantoms. A comparative study of CEST analysis techniques established a model-based approach, Bloch-McConnell model analysis, as the most robust for measuring pH-weighted signals in a clinical setting. Repeatability was improved by isolating non-CEST effects which attenuate signals of interest. The Bloch-McConnell model was developed further to explore whether more biologically-precise quantification of CEST effects was both possible and necessary. The additional model complexity, whilst more reflective of tissue biology, diminished contrast that distinguishes tissue fate, implying the biology is more complex than pH alone. The same model complexity could be used reveal signal patterns associated with tissue outcome that were otherwise obscured by competing CEST processes when observed through simpler models. Improved quantification techniques were demonstrated which were sufficiently robust to be used on clinical data, but also provided insight into the different biological processes at work in ischaemic tissue in the early stages of the disease. The complex array of competing processes in pathological tissue has underscored a need for analysis tools adequate for investigating these effects in the context of human imaging. The trends herein identified at the tissue level support the use of quantitative CEST MRI analysis as a clinical metabolic imaging tool in the investigation of ischaemic stroke.
22	Action in Chronic Fatigue Syndrome: an Enactive Psycho-phenomenological and Semiotic Analysis of Thirty New Zealand Women's Experiences of Suffering and Recovery Hart, M J Alexandra January 2010 (has links) This research into Chronic Fatigue Syndrome (CFS) presents the results of 60 first-person psycho-phenomenological interviews with 30 New Zealand women. The participants were recruited from the Canterbury and Wellington regions, 10 had recovered. Taking a non-dual, non-reductive embodied approach, the phenomenological data was analysed semiotically, using a graph-theoretical cluster analysis to elucidate the large number of resulting categories, and interpreted through the enactive approach to cognitive science. The initial result of the analysis is a comprehensive exploration of the experience of CFS which develops subject-specific categories of experience and explores the relation of the illness to universal categories of experience, including self, ‘energy’, action, and being-able-to-do. Transformations of the self surrounding being-able-to-do and not-being-able-to-do were shown to elucidate the illness process. It is proposed that the concept ‘energy’ in the participants’ discourse is equivalent to the Mahayana Buddhist concept of ‘contact’. This characterises CFS as a breakdown of contact. Narrative content from the recovered interviewees reflects a reestablishment of contact. The hypothesis that CFS is a disorder of action is investigated in detail. A general model for the phenomenology and functional architecture of action is proposed. This model is a recursive loop involving felt meaning, contact, action, and perception and appears to be phenomenologically supported. It is proposed that the CFS illness process is a dynamical decompensation of the subject’s action loop caused by a breakdown in the process of contact. On this basis, a new interpretation of neurological findings in relation to CFS becomes possible. A neurological phenomenon that correlates with the illness and involves a brain region that has a similar structure to the action model’s recursive loop is identified in previous research results and compared with the action model and the results of this research. This correspondence may identify the brain regions involved in the illness process, which may provide an objective diagnostic test for the condition and approaches to treatment. The implications of this model for cognitive science and CFS should be investigated through neurophenomenological research since the model stands to shed considerable light on the nature of consciousness, contact and agency. Phenomenologically based treatments are proposed, along with suggestions for future research on CFS. The research may clarify the diagnostic criteria for CFS and guide management and treatment programmes, particularly multidimensional and interdisciplinary approaches. Category theory is proposed as a foundation for a mathematisation of phenomenology. action Chronic Fatigue Syndrome Myalgic Encephalomyelitis Chronic Immune Deficiency Syndrome enaction social enaction social enactivism enactive psycho-phenomenological psychophenomenological vipassana groundlessness mind-body korper leib co-generative Focusing co-creative environment Antonio Damasio reciprocal constraints Pierre Vermersch Claire Petitmengin Antione Lutz narrative discourse phenomenal invariants Evan Thompson Merleau-Ponty Algirdis Julien Greimas Husserl first-person Fransisco Varela modelling invariants Natalie Depraz isotope John Boyd OODA loop Jonathan Shear Shaun Gallagher Arthur Kleinman Humberto Maturana second-person Alva Noe Dan Zahavi stages Embodied Mind Canterbury Wellington New Zealand non-dual non-reductive embodied phenomenological third-person graph-theoretical cluster analysis cognitive science experience solution subject-specific categories universal categories universal categories self energy illness process intersubjectivity Mahayana Buddhism contact narrative recovered making sense recursive loop perception dynamical decompensation neurology diagnosis empathy treatment management neurophenomenological neurophenomenology consciousness veracity agency multidimensional interdisciplinary category theory enculturation mathematisation of phenomenology interview nomenclature diagnostic criteria incidence prevalence coping strategy etiology epidemiology psychosomatic medicine meaning women girl female anthropology sociology cognitive behavioral therapy exercise therapy recovery mindful awareness suffering symbolisation Prasangika no-self aggregates wheel of karma cognition basic element analysis mental factors operational closure stereotypes enactive ontologically fragile self grief process-knowledge epoche phenomenal invariants textual invariants compound meaning saturation formalisation cluster analysis inter-session review inter-individual validation explicitation interview intricacy confidence psychophenomenology self-esteem sanction self dis-integration permanence continuity ego-self emotion surrender semiotic square meditation empathy semiotic compassion existential feelings goal obstruction movement transformation change somatic Giovanna Colombetti agoraphobia panic anxiety psychotherapy sleep rest pain weakness strength stamina Diego Cosmelli heaviness food chemicals allergy recovering despair frustration helplessness fear efference valence afference as-if-body-loop consciousness representation attention recovery intention sustainable sustainability neurasthenia existential feelings asthenia hysteria mononucleosis samatha-vispasnya prajna vijnana Eugene Gendlin Abhidharma dukkha shamatha interdependence vipashyana

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Quantifying impaired metabolism following acute ischaemic stroke using chemical exchange saturation transfer magnetic resonance imaging

Action in Chronic Fatigue Syndrome: an Enactive Psycho-phenomenological and Semiotic Analysis of Thirty New Zealand Women's Experiences of Suffering and Recovery