38 resultados para Other Analytical, Diagnostic and Therapeutic Techniques and Equipment

em Deakin Research Online - Australia


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The reaction of tris(2,2’-bipyridyl)ruthenium(III) (Ru(bipy) 33+) with various analytes to generate chemiluminescence has been well documented. This investigation sought to undertake a chemiluminometic study of the reactions of Ru(bipy) 33+ with selected Papaver Somniferum alkaloids and specifically synthesised phenethylamines. The investigation, based on a kinetic study, primarily addressed the effect of varying reaction conditions (pH) on Ru(bipy) 33+ chemiluminescence production. To monitor these reactions, a batch chemiluminometer was specifically designed, fabricated and automated to conduct an extensive study on the selected compounds of interest. The instrumentation incorporated a custom built reaction cell and comprised an ‘on-line’ sample preparation system with which calibration standards could be automatically prepared. The instrumentation provided both time-independent (peak area) and time-dependent (kinetic profile) information. A novel approach to the stabilisation of Ru(bipy) 33+ as a chemiluminescencent reagent was also investigated and a recirculating system was employed with the batch chemiluminometer to provide a stable supply of Ru(bipy) 33+. Codeine, thebaine and 6-methoxy-codeine were the Papaver Somniferum alkaloids selected for this study and several N-methylated and N,N-dimethylated phenethylamines and methoxy-substituted phenetheylamines were also synthesised to investigate the affect of pH on the chemiluminescence emission efficiency. The versatility of the batch chemiluminometer facilitated the kinetic study of numerous analytes over a broad pH range. The exemplary performance of the chemiluminometer as an analytical instrument, was demonstrated by the calibration functions, based on peak area data, which exhibited excellent linearity and sensitivity. The estimated detection limits (3s) for the selected alkaloids were in the range 2 x 10-9 M to 7 x 10-9 at pH 5.0 and above, which compared favourably to detection limits for the same compounds determined using FIA. Relative standard deviations (n=5) for peak areas ranged between 1% to 5% with a mean of 3.1% for all calibration standards above 2.5 x 10-8 M. Correlation between concentration and peak area, irrespective of pH and analyte was excellent, with all but two calibration functions having r-squared values greater than 0.990. The analytical figures of merit exemplified the precision and robustness of the reagent delivery and ‘on-line’ sample preparation, as well as the sensitivity of the system. The employment of the chemiluminometer for the measurement of total chemiluminescence emission (peak area) was in itself a feasible analytical technique, which generated highly reproducible and consistent data. Excellent analytical figures of merit, based on peak area, were similarly achieved for the phenethylamines. The effects of analyte structure on chemiluminescence activity was also investigated for the alkaloids and the phenethylamines. Subtle structural variations between the three alkaloids resulted in either a moderately reduced or enhanced total emission that was two or three fold difference only. A significant difference in reaction kinetics was observed between thebaine and codeine/6-methoxy-codeine, which was dependent upon pH. The time-dependent data, namely the observed rate constants for the initial rise in intensity and for the subsequent decay rate, were obtained by fitting a mathematical function (based on the postulated reaction mechanism) to the raw data. The determination of these rate constants for chemiluminescence reactions highlighted the feasibility for utilising such measurements for quantitative analytical applications. The kinetic data were used to discriminate between analyte responses in order to determine the concentrations of individual analytes in a binary mixture. A preliminary, multi-component investigation performed on a binary mixture of codeine and 6-methoxy-codeine (1:1) successfully determined the concentrations of these individual components using such rate constant measurements. Consequently, variations in kinetics resulted in a significant difference between the relative chemiluminescence response based on peak area measurements and the relative response base on peak height measurements obtained using FIA. With regards to the observed reactivity of secondary amines and tertiary amines, chemiluminescence peak area determinations confirmed the vital role of pH on reaction efficiency, which was governed by structural features and kinetics. The tertiary amines investigated generally produced a greater emission under acidic conditions than the corresponding secondary amines. However, the measured chemiluminescence responses were highly dependent upon pH, with similar peak areas obtained for both amine groups under slightly alkaline conditions.

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Technology education provides children with opportunities to be creative as they engage in problem solving and make products that address human needs. When thinking creatively, children generate new ideas through remote associations and brainstorming and this type of thinking is enhanced when attention is allowed to wander in a relaxed and uncompetitive environment. Research shows that the two mental states (generative and nongenerative/analytical) cannot exist simultaneously (Howard-Jones 2002). It follows that at some point in the technological process a child’s generative mental state needs to give way to a nongenerative, analytical state so that the child can focus on analysing information. This research project aims to investigate the impact of analytical thinking on creativity in the context of technology education in young children.

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Analytical modelling of deep drawing process is of value in preliminary process design to illustrate the influence of major variables including friction and strain hardening on punch loads, cup dimensions and process limits. In this study, analytical models including theoretical solution and a series of finite element models are developed to account for the influences of process parameters including friction coefficient, tooling geometry and material properties on deep drawing of metal cups. The accuracy of both the theoretical and finite element solutions is satisfactory compared with those from experimental work.

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Short-term psychodynamic psychotherapy (STPP) is a widely practised form of psychological intervention. Given that the Roth and Fonagy (1996) review concluded that there was a lack of confirming evidence for STPP, the current review is focused on studies published between 1996 and 2006 that evaluate the efficacy of STPP. As a result of a systematic literature review, 18 studies were found that met inclusion criteria consistent with those used by Roth and Fonagy (1996) for selection of studies, patient groupings and definition of therapeutic method. In general these studies add to an increasing body of evidence suggesting that STPP can be an effective psychological treatment for individuals experiencing mental health problems. Specifically, for depression STPP can be equal in effects to other psychological treatments and is significantly better than no treatment in the short term. Furthermore, emerging process data indicate that there is a significant relationship between the use of specific psychodynamic therapeutic techniques and the alleviation of depressive symptoms. Increasing evidence has emerged to support STPP as a treatment for generalized anxiety disorder, panic disorder and some personality disorders. There remains limited evidence for the use of STPP treatment for patients with anxiety disorders that relate more to stress. Very limited and inconclusive evidence currently exists to support STPP as a treatment for bipolar disorder, eating disorders and drug dependency. Future research needs to include broader assessment measures, long-term follow up, studies that maintain an identifiable focus, and research that includes a focus on psychotherapy process variables as they interact with outcomes.

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Michael Dummett has argued that the linguistic turn, initiated by Frege, is the decisive moment in the birth of the analytical tradition and what distinguishes that tradition from other movements. The thesis of the paper is that Dummett’s account of the origins of the analytical tradition understates the extent to which Frege’s work, and the linguistic turn more generally, are responses to antinomies in the modern philosophical project. An adequate characterisation of the origins of the analytic tradition presupposes an account of the fundamental conceptual shift that occurred during the time of the scientific revolution and the epistemological problems that arose in conjunction with this shift. This is why it is misleading to assert, with Dummett, that the really interesting developments in terms of understanding the analytical tradition are subsequent to Frege. The most productive contrast in terms of understanding the origins of the analytical tradition is not between pre and post Fregean thought, the paper argues, but between modern and premodern conceptions of philosophy and its relation to the world of everyday experience.

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Cardiac autonomic neuropathy (CAN) poses an important clinical problem, which often remains undetected due difficulty of conducting the current tests and their lack of sensitivity. CAN has been associated with growth in the risk of unexpected death in cardiac patients with diabetes mellitus. Heart rate variability (HRV) attributes have been actively investigated, since they are important for diagnostics in diabetes, Parkinson's disease, cardiac and renal disease. Due to the adverse effects of CAN it is important to obtain a robust and highly accurate diagnostic tool for identification of early CAN, when treatment has the best outcome. Use of HRV attributes to enhance the effectiveness of diagnosis of CAN progression may provide such a tool. In the present paper we propose a new machine learning algorithm, the Multi-Layer Attribute Selection and Classification (MLASC), for the diagnosis of CAN progression based on HRV attributes. It incorporates our new automated attribute selection procedure, Double Wrapper Subset Evaluator with Particle Swarm Optimization (DWSE-PSO). We present the results of experiments, which compare MLASC with other simpler versions and counterpart methods. The experiments used our large and well-known diabetes complications database. The results of experiments demonstrate that MLASC has significantly outperformed other simpler techniques.

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Background: In mental health, policy-makers and planners are increasingly being asked to set priorities. This means that health economists, health services researchers and clinical investigators are being called upon to work together to define and measure costs. Typically, these researchers take available service utilisation data and convert them to costs, using a range of assumptions. There are inefficiencies, as individual groups of researchers frequently repeat essentially similar exercises in achieving this end. There are clearly areas where shared or common investment in the development of statistical software syntax, analytical frameworks and other resources could maximise the use of data.

Aims of the Study: This paper reports on an Australian project in which we calculated unit costs for mental health admissions and community encounters. In reporting on these calculations, our purpose is to make the data and the resources associated with them publicly available to researchers interested in conducting economic analyses, and allow them to copy, distribute and modify them, providing that all copies and modifications are available under the same terms and conditions (i.e., in accordance with the `Copyleft' principle). Within this context, the objectives of the paper are to: (i) introduce the `Copyleft' principle; (ii) provide an overview of the methodology we employed to derive the unit costs; (iii) present the unit costs themselves; and (iv) examine the total and mean costs for a range of single and comorbid conditions, as an example of the kind of question that the unit cost data can be used to address.

Method: We took relevant data from the Australian National Survey of Mental Health and Wellbeing (NSMHWB), and developed a set of unit costs for inpatient and community encounters. We then examined total and mean costs for a range of single and comorbid conditions.

Results: We present the unit costs for mental health admissions and mental health community contacts. Our example, which explored the association between comorbidity and total and mean costs, suggested that comorbidly occurring conditions cost more than conditions which occur on their own.

Discussion: Our unit costs, and the materials associated with them, have been published in a freely available form governed by a provision termed `Copyleft'. They provide a valuable resource for researchers wanting to explore economic questions in mental health.

Implications for Health Policies: Our unit costs provide an important resource to inform economic debate in mental health in Australia, particularly in the area of priority-setting. In the past, such debate has largely been based on opinion. Our unit costs provide the underpinning to strengthen the evidence-base of this debate.

Implications for Further Research: We would encourage other Australian researchers to make use of our unit costs in order to foster comparability across studies. We would also encourage Australian and international researchers to adopt the `Copyleft' principle in equivalent circumstances. Furthermore, we suggest that the provision of `Copyleft'-contingent funding to support the development of enabling resources for researchers should be considered in the planning of future large-scale collaborative survey work, both in Australia and overseas.