The time course of changes in retinal vessel diameter in response to differing durations of flicker light provocation

Purpose: To determine the response of retinal vessels to differing durations of flicker light (FL) sitmulation. Methods: We recorded retinal arterial and venous vessel dilation to 12.5 Hz flicker light provocation (Retinal Vessel Analyzer, Imedos Systems) of varying duration (5, 7, 10 and 20 seconds) in twelve healthy young individuals (age range 26-45 yrs). All participants underwent a full ocular examination including intraocular pressure and blood pressure measurements. Results: Maximum dilation (MD) did not show a significant dependence on flicker duration in arteries whereas maximum constriction (MC) did. However, in veins MD significantly increased with flicker duration. Approximately 80-90% of MD in arteries is reached within 10 seconds of flicker light stimulation. Conclusions: The vast majority of arterial dilatory capacity is reached within 10 seconds of flicker light stimulation even though venous dilation continues strongly. Since the MC of arteries shows a significant dependence on flicker duration measurements at two different durations can provide more information about the retinal vascular system than at a single flicker duration alone.

Do gender and year of study affect the ability of the theory of planned behaviour to predict binge-drinking intentions and episodes?

Background: The present study tested the utility of the theory of planned behaviour (TPB), augmented with anticipated regret, as a model to predict binge-drinking intentions and episodes among female and male undergraduates and undergraduates in different years of study. Method: Undergraduate students (N = 180, 54 males, 126 females, 60 per year of study) completed baseline measures of demographic variables, binge-drinking episodes (BDE), TPB constructs and anticipated regret. BDE were assessed one-week later. Results: The TPB accounted for 60% of the variance in female undergraduates' intentions and 54% of the variance in male undergraduates' intentions. The TPB accounted for 57% of the variance in intentions in first-year undergraduates, 63% of the variance in intentions in second-year undergraduates and 68% of the variance in intentions in final-year undergraduates. Follow-up BDE was predicted by intentions and baseline BDE for female undergraduates as well as second- and final-year undergraduates. Baseline BDE predicted male undergraduates’ follow-up BDE and first-year undergraduates’ follow-up BDE. Conclusion: Results show that while the TPB constructs predict undergraduates’ binge-drinking intentions, intentions only predict BDE in female undergraduates, second- and final-year undergraduates. Implications of these findings for interventions to reduce binge drinking are outlined.

An action research study with low proficiency learners in Japan to promote the learning of vocabulary through collocations.

This action research (AR) study explores an alternative approach to vocabulary instruction for low-proficiency university students: a change from targeting individual words from the general service list (West, 1953) to targeting frequent verb + noun collocations. A review of the literature indicated a focus on collocations instead of individual words could potentially address the students’ productive challenges with targeted vocabulary. Over the course of four reflective cycles, this thesis addresses three main aspects of collocation instruction. First, it examines if the students believe studying collocations is more useful than studying individual lexical items. Second, the thesis investigates whether a focus on collocations will lead to improvements in spoken fluency. This is tested through a comparison of a pre-intervention spoken assessment task with the findings from the same task completed 15 weeks later, after the intervention. Third, the thesis explores different procedures for the instructing of collocations under the classroom constraints of a university teaching context. In the first of the four reflective cycles, data is collected which indicates that the students believe a focus on collocations is superior to only teaching individual lexical items, that in the students’ opinion their productive abilities with the targeted structures has improved, and that delexicalized verb collocations are problematic for low-proficiency students. Reflective cycle two produces evidence indicating that productive tasks are superior to receptive tasks for fluency development. In reflective cycle three, productively challenging classroom tasks are investigated further and the findings indicate that tasks with higher productive demands result in greater improvements in spoken fluency. The fourth reflective cycle uses a different type of collocation list: frequent adjective + noun collocations. Despite this change, the findings remain consistent in that certain types of collocations are problematic for low-proficiency language learners and that the evidence shows productive tasks are necessary to improve the students’ spoken ability.

Study of management decision making by ward sisters in a hospital and the effects on decision making after the implementation of a decision support sytem

This thesis considers management decision making at the ward level in hospitals especially by ward sisters, and the effectiveness of the intervention of a decision support system. Nursing practice theories were related to organisation and management theories in order to conceptualise a decision making framework for nurse manpower planning and deployment at the ward level. Decision and systems theories were explored to understand the concepts of decision making and the realities of power in an organisation. In essence, the hypothesis was concerned with changes in patterns of decision making that could occur with the intervention of a decision support system and that the degree of change would be governed by a set of `difficulty' factors within wards in a hospital. During the course of the study, a classification of ward management decision making was created, together with the development and validation of measuring instruments to test the research hypothesis. The decision support system used was rigorously evaluated to test whether benefits did accrue from its implementation. Quantitative results from sample wards together with qualitative information collected, were used to test this hypothesis and the outcomes postulated were supported by these findings. The main conclusion from this research is that a more rational approach to management decision making is feasible, using information from a decision support system. However, wards and ward sisters that need the most assistance, where the `difficulty' factors in the organisation are highest, benefit the least from this type of system. Organisational reviews are needed on these identified wards, involving managers and doctors, to reduce the levels of un-coordinated activities and disruption.

A study of the growth and differentiation of the human adenocarcinoma of the colon cell line HT-29

The HT-29 human colon adenocarcinoma cell line, like many epithelial cells, displays an undifferentiated phenotype when cultured on plastic substrata. Biochemical markers of differentiation, such as brush border associated enzymes and carcinoembryonic antigen were expressed at very low levels. The differentiation-inducing effects of the culture of HT-29 cells on collagen type I gels were evaluated, and were assessed by morphological appearance, brush border associated enzyme activities and the secretion of CEA. The effect that this more physiological environment had on their chemosensitivity to a panel of chemotherapeutic agents was determined, so as to indicate whether this system could be used to improve the selectivity of screening for novel anticancer agents. Initial studies were performed on HT-29 cells derived from cells seeded directly from plastic substrata onto the collagen gels (designated Non-PPC gels). Their time of exposure to the collagen was limited to the time course of a single experiment and the results suggested that a longer, more permanent exposure might produce a more pronounced differentiation. HT-29 cells were then passaged continuously on collagen gels for a minimum of 10 passages prior to experimentation (designated PPC gels). The same parameters were measured, and compared to those for the cells grown on plastic and on the non-passaged collagen gels (Non-PPC) from the original studies. Permanently passaged cells displayed a similar degree of morphological differentiation as the non-passaged cells, with both culture conditions resulting in a more pronounced differentiation than that achieved by culture on plastic. It was noted that the morphological differentiation observed was very heterogeneous, a situation also seen in xenografted tumours in vivo. The activity of alkaline phosphatase and the production of CEA was higher in the cells passaged on collagen (PPC) than the cells cultured on non-passaged collagen gel (Non-PPC) and plastic. The biochemical determination of aminopeptidase activity showed that collagen gel culture enhanced the activity in both non-passaged and passaged HT-29 cells above that of the cells cultured on plastic. However, immunocytochemical localization of aminopeptidase and sucrase-isomaltase of samples of cells grown on the various substrata for 7, 14, 21 and 28 days showed a reduction in both enzymes in the cells grown on collagen gels when compared to cells grown on plastic. The reason for the discrepancy between the two assays for aminopeptidase is at this stage unexplained. Although, there was evidence to suggest that the culture of HT-29 cells on collagen gels was capable of inducing morphological and biochemical markers of enterocytic differentiation, there were no differences in the chemosensitivity of the different cell groups to a panel of anticancer agents. Preliminary studies suggested that the ability of the cells to polarize by their culture on porous filter chambers without any exogenous ECM was sufficient to enhance HT-29 differentiation and the onset of differentiation was probably correlated with the production of ECM by the cells themselves.

Experiences of patients with age-related macular degeneration receiving anti-vascular endothelial growth factor therapy:a qualitative study

The societal cost for the average health authority in the United Kingdom for the care of wet age-related macular degeneration (AMD) has been suggested to be around £7.4 million. It is vital that the best possible care based on the best available evidence is provided to reduce the impact of AMD on patients' lives and the financial cost to the health-care system. This study explored the experiences of AMD patients treated with intravitreal ranibizumab injections. Three semistructured interviews were conducted with seven participants over the course of 18 months. Transcripts were analysed using interpretative phenomenological analysis. Analysis identified four themes: preparing for treatment, the treatment process, patient-provider communication, and results of treatment. Patient experiences highlighted the need to move away from the reliance on letters for information provision, and the need for clearer guidelines about when to cease AMD treatment. Interviews highlighted the need for the inclusion of rigorous qualitative evidence with experiential data in future good clinical practice guideline development for AMD. © The Author(s) 2013.

'I'd like to know what causes it, you know, anything I've done?' Are we meeting the information and support needs of patients with macular degeneration? A qualitative study

Objective: To examine patients' experiences of information and support provision for age-related macular degeneration (AMD) in the UK. Study design: Exploratory qualitative study investigating patient experiences of healthcare consultations and living with AMD over 18 months. Setting: Specialist eye clinics at a Birmingham hospital. Participants: 13 patients diagnosed with AMD. Main outcome measures: Analysis of patients' narratives to identify key themes and issues relating to information and support needs. Results: Information was accessed from a variety of sources. There was evidence of clear information deficits prior to diagnosis, following diagnosis and ongoing across the course of the condition. Patients were often ill informed and therefore unable to self-advocate and recognise when support was needed, what support was available and how to access support. Conclusions: AMD patients have a variety of information needs that are variable across the course of the condition. Further research is needed to determine whether these experiences are typical and identify ways of translating the guidelines into practice. Methods of providing information need to be investigated and improved for this patient group.

Microstructural study of aluminide surface coatings on single crystal nickel base superalloy substrates

Aluminide diffusion coatings are frequently employed to enhance the oxidation resistance of nickel base superalloys. However, there is a concern that the presence of an aluminide coating could influence the properties of the coated superalloy, especially in respect of fatigue behaviour. To understand the nature of the effects of surface coatings on the fatigue properties of superalloys, an understanding of microstructural development within both the coating and the coating/substrate interfacial zone during high temperature fatigue testing is necessary. This paper is concerned with microstructural changes in aluminide diffusion coatings on single crystal γ′ strengthened superalloy substrates during the course of high temperature fatigue testing. The 'edge on' transmission electron microscopy technique is employed to study cross-sections of two stage (aluminization plus diffusion treatment) coated superalloy samples. The paper examines the degradation of the coating produced by phase transformations induced by loss of aluminum from the coating and/or aging of the coating. Aluminum removal both by interdiffusion with the substrate and by oxidation of the coating surface is considered. Microstructural development in the portion of the substrate influenced by interdiffusion with the coating is also discussed.

Study on fatigue and energy-dissipation properties of nanolayered Cu/Nb thin films

Energy dissipation and fatigue properties of nano-layered thin films are less well studied than bulk properties. Existing experimental methods for studying energy dissipation properties, typically using magnetic interaction as a driving force at different frequencies and a laser-based deformation measurement system, are difficult to apply to two-dimensional materials. We propose a novel experimental method to perform dynamic testing on thin-film materials by driving a cantilever specimen at its fixed end with a bimorph piezoelectric actuator and monitoring the displacements of the specimen and the actuator with a fibre-optic system. Upon vibration, the specimen is greatly affected by its inertia, and behaves as a cantilever beam under base excitation in translation. At resonance, this method resembles the vibrating reed method conventionally used in the viscoelasticity community. The loss tangent is obtained from both the width of a resonance peak and a free-decay process. As for fatigue measurement, we implement a control algorithm into LabView to maintain maximum displacement of the specimen during the course of the experiment. The fatigue S-N curves are obtained.