Factors contributing towards falls in older age during overground walking have been widely studied. Stepping behaviour, balance and head posture control during stair negotiation in young adults (YA) and older adults with either lower (LROA) or higher (HROA) risk of falling during midstair negotiation have not been investigated. The aims of the thesis were threefold. Firstly, age-related changes in gaze behaviour were investigated. The main finding was that older adults fixate stair edges for longer than YA. Secondly, the effect of manipulating visual information on stepping parameters and balance control was compared between YA, LROA and HROA. For stair ascent, stepping and balance control was preserved in LROA and HROA and highlighted stair edges led to increased foot clearance in all groups. For stair descent, HROA demonstrated smaller foot clearance than LROA and highlighted stair edges improved balance in LROA and HROA. Thirdly, head posture was studied in YA, LROA and HROA. Compared to walking, LROA and HROA demonstrated more variable head posture than YA. Overall the findings suggest that adults use visual and probably proprioceptive information about stair edge locations to negotiate stairs and HROA benefited from highlighted stair edges. HROA should be included in future stair negotiation studies.

Perhexiline is an anti-anginal drug that is thought to shift myocardial metabolism from \(\beta\)-oxidation of fatty acids to glucose utilisation. An associated improvement in energy efficiency may be beneficial in ischaemia-reperfusion as an adjunct to established techniques for myocardial protection during cardiac surgery. In this thesis, I conduct a prospective double-blind randomised placebo-controlled trial of oral perhexiline in patients undergoing coronary artery surgery, obtaining samples of serum, right atrium and left ventricle. I measure the concentration of perhexiline using high performance liquid chromatography and find that although highly concentrated in the heart, it may not have reached steady-state in the ventricular myocardium. I perform enzymatic colourimetry and ultra-high resolution mass spectrometry to detect changes in carbohydrate and lipid metabolism; however, the myocardial metabolic profiles of patients on perhexiline are indistinguishable from controls. On analysing the results of the clinical trial, I find no improvement in the primary endpoint, the incidence of a low cardiac output episode, or any secondary outcomes. I conclude that preoperative oral perhexiline does not improve clinical markers of myocardial protection and despite significant accumulation in the myocardium, it has no significant effect on the measurable metabolic profile of the heart at the time of surgery.

This thesis comprises two volumes, representing the research and clinical elements submitted to the University of Birmingham in partial fulfillment of the degree of Doctor of Clinical Psychology (DClinPsy). The first volume is the research component and contains three papers. The first paper is a review of the literature from 1980 to the present day, which has examined intellectual, behavioural and psychological characteristics in participants with Sotos syndrome. The second paper is an empirical study which examines the behavioural phenotype of participants with Sotos syndrome in comparison to 3 other genetic syndromes using standardised, well validated questionnaires. The third paper summarises these in language accessible to the general public. The second volume is the clinical component containing four Clinical Practice Reports and the abstract for an oral examination. These papers represent different aspects of work conducted during clinical placements. They include a paper which formulates from two different psychological perspectives, a service evaluation, a single case experimental design and a case study.

Thesis (Ph. D.)--University of Texas at Austin, 1998. / Vita. Includes bibliographical references (leaves 153-162). Available also in a digital version from Dissertation Abstracts.

Static and dynamic balance are essential in daily and sports life. Many factors have been identified as influencing static balance control, two of which are carrying additional weight and localized muscle fatigue but their influence on dynamic balance in sport activities has not been fully established. Therefore, the aim of this thesis was to investigate the characteristics of dynamic balance in sport related activities, with specific reference to the influence of body mass changes and muscular fatigue. Study one: The objectives of study one (methodological study, n = 5) were to apply the extrapolated Centre of Mass (XCoM) method and other relevant variables (centre of pressure, CoP; Centre of Mass, CoM; shear forces, Fh; kinetic energy, KE; momentum, P; and angular impulse, AI) to investigate sport related activities such as hopping and jumping. Many studies have represented the CoP data without mentioning its accuracy so several experiments were done to establish the agreement between the CoP and the projected CoM in a static condition. It was found that there was an inaccuracy with the average difference about 4mm. This meant that the angular impulse could not be reliably calculated. Its horizontal component, representing the Friction Torque (Q), could be reliably computed for dynamic balance. The implementation of the XCoM method was found to be practical for evaluating both static and dynamic balance. The general findings were that the CoP, the CoM, the XCoM, Fh, and Qwere more informative than the other variables (e.g. KE, P, and AI) during static and dynamic balance. The XCoM method was found to be applicable to dynamic balance as well as static balance. Study 2: The objectives of study two (baseline study, n =20) were to implement Matlab procedures for quantifying selected static and dynamic balance variables, establish baseline data of selected variables which characterize static and dynamic balance activities in a population of healthy young adult males, and to examine any trial effects on these variables. The results indicated that the implementation of Matlab procedures for quantifying selected static and dynamic balance variables was practical and enabled baseline data to be established for selected variables. There was no significant trial effect. Recommendations were made for suitable tests to be used in later studies. Specifically it was found that one foot-tiptoes tests either in static or dynamic balance are too challenging for most participants in normal circumstances. A one foot-flat eyes open test was considered to be representative and challenging for static balance, while adding further vertical jump and landing tests (two feet flat and one foot flat vertical jump) to the horizontal jumping and hopping for dynamic balance was considered to be more representative of sports situations. The main differences between horizontal and vertical jumping were in anterior-posterior direction. Study 3: The objectives of study three (differentiation study, n =20) were to establish the influence of physical (external added weight) and neurophysiological (fatigue) factors on static and dynamic balance in sport related activities. This was typified statically by the Romberg test (one foot flat, eyes open) and dynamically by jumping and hopping in both horizontal and vertical directions. Statically, added weight increased body's inertia and therefore decreased body sway in anterior-posterior direction though not significantly. Dynamically, added weight significantly increased body sway in both mideo-lateral and anterior-posterior directions, indicating instability, and the use of the counter rotating segments mechanism to maintain balance was demonstrated. Fatigue on the other hand significantly increased body sway during static balance as a neurophysiological adaptation primarily to the inverted pendulum mechanism. Dynamically, fatigue significantly increased body sway in both mideo-lateral and anterior-posterior directions again indicating instability but with a greater use of counter rotating segments mechanism. Differential adaptations for each of the two balance mechanisms (inverted pendulum and counter rotating segments) were found between one foot flat and two feet flat dynamic conditions, as participants relied more heavily on the first in the one foot flat conditions and relied more on the second in the two feet flat conditions. Conclusion: Results from this thesis are expected to aid towards advancing the understanding of balance in sport related activities, and can provide a solid foundation for future work in this area. In particular, a method was established to assess static and dynamic balance, baseline data for these associations was provided, and differential adaptations to physical or neurophysiological constraints were found. Valuable associations between specific variables and the first two mechanisms of balance were demonstrated.

Across the United States, Human Anatomy and Physiology (HA&P) courses typically have some of the highest withdrawal and failure rates on college campuses. These high enrollment course typically serve as gate-keepers for those individuals with aspirations of entering the medical field. In light of the growing national shortage of healthcare professionals, there is a pressing need to improve the state of HA&P education at a national scale. The goal of this dissertation is to understand why undergraduate students struggle to succeed in HA&P courses. I leveraged multiple frameworks from biology education research, physics education research, and cognitive psychology to understand the source of student difficulty in HA&P. I used a mixed-methods approach to unpack how students reason about the complex phenomena covered in HA&P classes. The data presented here suggest student difficulties in HA&P are not the product of a culmination of individual conceptual difficulties. Rather, this work suggests students have difficulty reasoning with the many complex systems that are at the heart of HA&P curriculum. Students appear to frame these complex systems in a manner that activates reasoning strategies that are often in conflict with course goals. The findings from this work advocate for a dynamic view of student cognition that recognizes the implications of context features on student reasoning of complex systems.

In obesity, lipids stored in muscle as lipid droplets (LDs) lead to accumulation of fatty acid (FA) metabolites and insulin resistance. This research involves development of immunofluorescence microscopy methods to generate novel information on the subcellular content and distribution of key enzymes that play a role in the underlying mechanisms. Chapters 3 and 4 describe visualisation of two lipid synthesising enzymes. Both are more abundant in type I muscle fibres. Chapter 5 reveals no differences between these enzymes in non obese and obese elderly women. Chapter 6 reveals that a key lipolytic enzyme (ATGL) has a higher content in type I fibres, but its activator does not. Chapter 7 describes visualisation of SNAP23 and reveals a high content at the plasma membrane and mitochondria and low content in LDs. Chapter 8 fails to observe a difference between obese and non obese elderly women in plasma membrane SNAP23, and therefore fails to confirm the hypothesis that LDs hijack SNAP23. However, obese women have less SNAP23 in mitochondria and this may limit FA oxidation. In conclusion this thesis describes several novel mechanisms by which obesity leads to accumulation of FA metabolites and insulin resistance. The developed methods will be a valuable novel tool for future diabetes research.