The use of electronic portal imaging to verify patient position during intensity-modulated radiotherapy delivered by the dynamic MLC technique

Purpose: The precise shape of the three-dimensional dose distributions created by intensity-modulated radiotherapy means that the verification of patient position and setup is crucial to the outcome of the treatment. In this paper, we investigate and compare the use of two different image calibration procedures that allow extraction of patient anatomy from measured electronic portal images of intensity-modulated treatment beams. Methods and Materials: Electronic portal images of the intensity-modulated treatment beam delivered using the dynamic multileaf collimator technique were acquired. The images were formed by measuring a series of frames or segments throughout the delivery of the beams. The frames were then summed to produce an integrated portal image of the delivered beam. Two different methods for calibrating the integrated image were investigated with the aim of removing the intensity modulations of the beam. The first involved a simple point-by-point division of the integrated image by a single calibration image of the intensity-modulated beam delivered to a homogeneous polymethyl methacrylate (PMMA) phantom. The second calibration method is known as the quadratic calibration method and required a series of calibration images of the intensity-modulated beam delivered to different thicknesses of homogeneous PMMA blocks. Measurements were made using two different detector systems: a Varian amorphous silicon flat-panel imager and a Theraview camera-based system. The methods were tested first using a contrast phantom before images were acquired of intensity-modulated radiotherapy treatment delivered to the prostate and pelvic nodes of cancer patients at the Royal Marsden Hospital. Results: The results indicate that the calibration methods can be used to remove the intensity modulations of the beam, making it possible to see the outlines of bony anatomy that could be used for patient position verification. This was shown for both posterior and lateral delivered fields. Conclusions: Very little difference between the two calibration methods was observed, so the simpler division method, requiring only the single extra calibration measurement and much simpler computation, was the favored method. This new method could provide a complementary tool to existing position verification methods, and it has the advantage that it is completely passive, requiring no further dose to the patient and using only the treatment fields.

Effects of introducing an interactive teaching and learning activity (TLA) in the engineering classroom

This research study examines qualitatively and quantitatively the influence of introducing an activity in the traditional engineering classroom. It studies instances of active learning and its relationship with the student learning outcomes. The primary purpose of this study was to compare the learning outcomes of students who were involved in an active TLA with those students who were not, instead they learned under traditional teaching and studying approaches. I present the argument that the introduction of a TLA in class stimulates student engagement bringing enormous benefits to student learning. The outcomes of this study were measured using qualitative and quantitative data to evaluate the levels of student engagement, achievement and satisfaction in the terms of Intended Learning Outcomes (ILOs). Results indicate that students held positive attitude towards the activities in class and also, that a positive link between TLA, learning approach and learning outcome exist. It also provides insights about the potential benefits of active learning when compared with traditional, passive and teacher-centred methods of teaching & learning.

Effects of soluble dietary cellulose on specific growth rate, survival and digestive enzyme activities in three freshwater crayfish (Cherax) species

Three native freshwater crayfish Cherax species are farmed in Australia namely; Redclaw (Cherax quadricarinatus), Marron (C. tenuimanus), and Yabby (C. destructor). Lack of appropriate data on specific nutrient requirements for each of these species, however, has constrained development of specific formulated diets and hence current use of over-formulated feeds or expensive marine shrimp feeds, limit their profitability. A number of studies have investigated nutritional requirements in redclaw that have focused on replacing expensive fish meal in formulated feeds with non-protein, less expensive substitutes including plant based ingredients. Confirmation that freshwater crayfish possess endogenous cellulase genes, suggests their potential ability to utilize complex carbohydrates like cellulose as nutrient sources in their diet. To date, studies have been limited to only C. quadricarinatus and C. destructor and no studies have compared the relative ability of each species to utilize soluble cellulose in their diets. Individual feeding trials of late-juveniles of each species were conducted separately in an automated recirculating culture system over 12 week cycles. Animals were fed either a test diet (TD) that contained 20% soluble cellulose or a reference diet (RD) substituted with the same amount of corn starch. Water temperature, conductivity and pH were maintained at constant and optimum levels for each species. Animals were fed at 3% of their body weight twice daily and wet body weight was recorded bi-weekly. At the end of experiment, all animals were harvested, measured and midgut gland extracts assayed for alpha-amylase, total protease and cellulase activity levels. After the trial period, redclaw fed with RD showed significantly higher (p<0.05) specific growth rate (SGR) compare with animals fed the TD while SGR of marron and yabby fed the two diets were not significantly different (p<0.05). Cellulase expression levels in redclaw were not significantly different between diets. Marron and yabby showed significantly higher cellulase activity when fed the RD. Amylase and protease activity in all three species were significantly higher in the animals fed with RD (Table 1). These results indicate that test animals of all species can utilize starch better than dietary soluble cellulose in their diet and inclusion of 20% soluble cellulose in diets does not appear to have any significant negative effect on their growth rate but survival was impacted in C. quadricarinatus while not in C. tenuimanus or C. destructor.

Perception and reality : meeting Australia’s physical activity guidelines for 12-18 year olds

Governments regularly publish empirically derived minimum physical activity (PA) guidelines for youth, in response to the ongoing trend of youth physical inactivity. The purpose of this investigation was to explore parents’ awareness of the national PA guidelines for youth, and adolescents’ and their parents’ perceptions of adolescent PA, and compare these to self-reported adolescent PA. A total of 115 adolescents (aged 12-14) and their parents completed questionnaire assessments. Parents responded to questions concerning their awareness of the national PA guidelines, and whether they believed their child to be sufficiently active. Adolescents completed the International Physical Activity Questionnaire for Adolescents, and questions concerning their perceived level of PA. Adolescents were deemed sufficiently active if they participated in an average of at least 60 minutes of moderate-to-vigorous PA each day. Overall, 104 (90.4%) adolescents and their parents had complete data sets and were included in the analysis. Of the 45 (43.3%) sufficiently and 59 (56.7%) insufficiently active adolescents, 42 (93%) and 41 (69.5%) respectively believed that they were active enough for good general health. Additionally, 41 (91.1%) parents of active and 44 (74.6%) parents of inactive adolescents either agreed or strongly agreed that their child participates in sufficient PA for good general health. Twenty-four (53.3%) parents of active adolescents were unaware of the national PA guidelines, with 10 (22.2%) neither aware or unaware, and 11 (24.4%) aware. Similar results were found for the parents of inactive adolescents with 31 (52.5%) unaware, 17 (28.8%) neither aware or unaware, and 11 (18.6%) aware. These results suggest that the youth PA guidelines are being inadequately received by both adolescents, and their parents. Opportunities to effectively communicate these guidelines such as embedment in curriculum for adolescents, or the dissemination of materials for parents, should be maximised by appropriate authorities.

Pseudo-marginal algorithms with multiple CPUs

The emergence of pseudo-marginal algorithms has led to improved computational efficiency for dealing with complex Bayesian models with latent variables. Here an unbiased estimator of the likelihood replaces the true likelihood in order to produce a Bayesian algorithm that remains on the marginal space of the model parameter (with latent variables integrated out), with a target distribution that is still the correct posterior distribution. Very efficient proposal distributions can be developed on the marginal space relative to the joint space of model parameter and latent variables. Thus psuedo-marginal algorithms tend to have substantially better mixing properties. However, for pseudo-marginal approaches to perform well, the likelihood has to be estimated rather precisely. This can be difficult to achieve in complex applications. In this paper we propose to take advantage of multiple central processing units (CPUs), that are readily available on most standard desktop computers. Here the likelihood is estimated independently on the multiple CPUs, with the ultimate estimate of the likelihood being the average of the estimates obtained from the multiple CPUs. The estimate remains unbiased, but the variability is reduced. We compare and contrast two different technologies that allow the implementation of this idea, both of which require a negligible amount of extra programming effort. The superior performance of this idea over the standard approach is demonstrated on simulated data from a stochastic volatility model.

Urban transit quality of service : user perception and behaviour

Despite its potential multiple contributions to sustainable policy objectives, urban transit is generally not widely used by the public in terms of its market share compared to that of automobiles, particularly in affluent societies with low-density urban forms like Australia. Transit service providers need to attract more people to transit by improving transit quality of service. The key to cost-effective transit service improvements lies in accurate evaluation of policy proposals by taking into account their impacts on transit users. If transit providers knew what is more or less important to their customers, they could focus their efforts on optimising customer-oriented service. Policy interventions could also be specified to influence transit users’ travel decisions, with targets of customer satisfaction and broader community welfare. This significance motivates the research into the relationship between urban transit quality of service and its user perception as well as behaviour. This research focused on two dimensions of transit user’s travel behaviour: route choice and access arrival time choice. The study area chosen was a busy urban transit corridor linking Brisbane central business district (CBD) and the St. Lucia campus of The University of Queensland (UQ). This multi-system corridor provided a ‘natural experiment’ for transit users between the CBD and UQ, as they can choose between busway 109 (with grade-separate exclusive right-of-way), ordinary on-street bus 412, and linear fast ferry CityCat on the Brisbane River. The population of interest was set as the attendees to UQ, who travelled from the CBD or from a suburb via the CBD. Two waves of internet-based self-completion questionnaire surveys were conducted to collect data on sampled passengers’ perception of transit service quality and behaviour of using public transit in the study area. The first wave survey is to collect behaviour and attitude data on respondents’ daily transit usage and their direct rating of importance on factors of route-level transit quality of service. A series of statistical analyses is conducted to examine the relationships between transit users’ travel and personal characteristics and their transit usage characteristics. A factor-cluster segmentation procedure is applied to respodents’ importance ratings on service quality variables regarding transit route preference to explore users’ various perspectives to transit quality of service. Based on the perceptions of service quality collected from the second wave survey, a series of quality criteria of the transit routes under study was quantitatively measured, particularly, the travel time reliability in terms of schedule adherence. It was proved that mixed traffic conditions and peak-period effects can affect transit service reliability. Multinomial logit models of transit user’s route choice were estimated using route-level service quality perceptions collected in the second wave survey. Relative importance of service quality factors were derived from choice model’s significant parameter estimates, such as access and egress times, seat availability, and busway system. Interpretations of the parameter estimates were conducted, particularly the equivalent in-vehicle time of access and egress times, and busway in-vehicle time. Market segmentation by trip origin was applied to investigate the difference in magnitude between the parameter estimates of access and egress times. The significant costs of transfer in transit trips were highlighted. These importance ratios were applied back to quality perceptions collected as RP data to compare the satisfaction levels between the service attributes and to generate an action relevance matrix to prioritise attributes for quality improvement. An empirical study on the relationship between average passenger waiting time and transit service characteristics was performed using the service quality perceived. Passenger arrivals for services with long headways (over 15 minutes) were found to be obviously coordinated with scheduled departure times of transit vehicles in order to reduce waiting time. This drove further investigations and modelling innovations in passenger’ access arrival time choice and its relationships with transit service characteristics and average passenger waiting time. Specifically, original contributions were made in formulation of expected waiting time, analysis of the risk-aversion attitude to missing desired service run in the passengers’ access time arrivals’ choice, and extensions of the utility function specification for modelling passenger access arrival distribution, by using complicated expected utility forms and non-linear probability weighting to explicitly accommodate the risk of missing an intended service and passenger’s risk-aversion attitude. Discussions on this research’s contributions to knowledge, its limitations, and recommendations for future research are provided at the concluding section of this thesis.

Design and interpretation of cell trajectory assays

Cell trajectory data is often reported in the experimental cell biology literature to distinguish between different types of cell migration. Unfortunately, there is no accepted protocol for designing or interpreting such experiments and this makes it difficult to quantitatively compare different published data sets and to understand how changes in experimental design influence our ability to interpret different experiments. Here, we use an individual based mathematical model to simulate the key features of a cell trajectory experiment. This shows that our ability to correctly interpret trajectory data is extremely sensitive to the geometry and timing of the experiment, the degree of motility bias and the number of experimental replicates. We show that cell trajectory experiments produce data that is most reliable when the experiment is performed in a quasi 1D geometry with a large number of identically{prepared experiments conducted over a relatively short time interval rather than few trajectories recorded over particularly long time intervals.

A retrospective cohort investigation of active range of motion within one week of open reduction and internal fixation of distal radius fractures

Distal radius fractures stabilized by open reduction internal fixation (ORIF) have become increasingly common. There is currently no consensus on the optimal time to commence range of motion (ROM) exercises post-ORIF. A retrospective cohort review was conducted over a five-year period to compare wrist and forearm range of motion outcomes and number of therapy sessions between patients who commenced active ROM exercises within the first seven days and from day eight onward following ORIF of distal radius fractures. One hundred and twenty-one patient cases were identified. Clinical data, active ROM at initial and discharge therapy assessments, fracture type, surgical approaches, and number of therapy sessions attended were recorded. One hundred and seven (88.4%) cases had complete datasets. The early active ROM group (n = 37) commenced ROM a mean (SD) of 4.27 (1.8) days post-ORIF. The comparator group (n = 70) commenced ROM exercises 24.3 (13.6) days post-ORIF. No significant differences were identified between groups in ROM at initial or discharge assessments, or therapy sessions attended. The results from this study indicate that patients who commenced active ROM exercises an average of 24 days after surgery achieved comparable ROM outcomes with similar number of therapy sessions to those who commenced ROM exercises within the first week.

Factors influencing sustainability outcomes of housing in subtropical Australia

Purpose: The challenges of providing housing that sustains its inhabitants socially, economically and environmentally, and is inherently sustainable for the planet as a whole, requires a holistic systems approach that considers the product, the supply chain and the market, as well as the inter-dependencies within and between each of these process points. The purpose of the research is to identify factors that impact the sustainability performance outcomes of residential dwellings and the diffusion of sustainable housing into the mainstream housing market. Design/methodology/approach: This research represents a snapshot in time: a recording of the experiences of seven Australian families who are “early adopters” of leading edge sustainable homes within a specific sustainable urban development in subtropical Queensland. The research adopts a qualitative approach to compare the goals and expectations of these families with the actual sustainability aspects incorporated into their homes and lifestyles. Findings: The results show that the “product” – a sustainable house – is difficult to define; that sustainability outcomes were strongly influenced by individual concerns and the contextual urban environment; and that economic comparisons with “standard” housing are challenging. Research limitations/implications: This qualitative study is based on seven families (13 individuals) in an Ecovillage in southeast Queensland. Although the findings make a significant contribution to knowledge, they may not be generalisable to the wider population. Originality/value: The experiences of these early adopter families suggest that the housing market and regulators play critical roles, through actions and language, in limiting or enhancing the diffusion of sustainable housing into the market.

Does board gender diversity have a financial impact? Evidence using stock portfolio performance.

There is growing regulatory pressure on firms worldwide to address the under-representation of women in senior positions. Regulators have taken a variety of approaches to the issue. We investigate a jurisdiction that has issued recommendations and disclosure requirements, rather than implementing quotas. Much of the rhetoric surrounding gender diversity centres on whether diversity has a financial impact. In this paper we take an aggregate (market-level) approach and compare the performance of portfolios of firms with gender diverse boards to those without. We also investigate whether having multiple women on the board is linked to performance, and if there is a within-industry effect. Overall, we do not find evidence of an association between diversity and performance. We find some weak evidence of a negative correlation between having multiple women on the board and performance, but that in some industries diversity is positively correlated with performance.

Effect of induced airway inflammation in asthma : the expression of trefoil factors, secretoglobins and genes involved in histone acetylation

Asthma is an incapacitating disease of the respiratory system, which causes extensive morbidity and mortality worldwide. Asthma affects more than 300 million people globally(Masoli et al. 2004). In Australia, it affects 10.2% of the population (Masoli et al. 2004) and causes 60,000 people to be hospitalised annually. Health care expenditure due to asthma in Australia was $606 million in 2004–2005. There are four primary biological factors that function in the initiation and exacerbation of asthma. Airway inflammation is important as it is often the first response to an airway insult, initiating the three other components: bronchoconstriction, mucus hyper-secretion and hyper-reactivity. The mediators involved in asthma are still not well understood, and current anti-inflammatory corticosteroid treatments are not effective with all asthmatics. As there is currently no cure for asthma, and airway inflammation is the primary component of the disease, it is important that we understand and investigate the mediators of airway inflammation to look for a potential cure and to produce better therapeutics to treat the inflammation. Trefoil factors (TFFs) and secretoglobins (SCGBs) are small secreted proteins involved in the mediation of inflammation and epithelial restitution. TFFs are pro-inflammatory and SCGBs anti-inflammatory by nature. The hypothesis of this study is that in response to induced acute airway inflammation, the expression of TFF1 and TFF3 will increase and expression of SCGB1A1 and SCGB3A2 will decrease in non-asthmatics (N-A), asthmatics medicating with bronchodilators (A-BD) and asthmatics medicating with corticosteroids (A-ST). When comparing the three groups, we expect to see higher expression of the TFFs in the A-BD group compared to the N-A and A-ST groups, indicating that inflammation is mediated by TFFs in asthma and that corticosteroid medication controls their expression as part of the control of inflammation. We expect to see the opposite with SCGBs, with a greater decrease in the A-BD group compared to the other two groups, suggesting that the A-BD group has the least anti-inflammatory activity in response to inflammatory insult. Epigenetic modification plays a role in the regulation of genes that initiate disease states such as inflammatory conditions and cancers. Histone acetylation is one such modification, which involves the acetylation of histones in chromatin by histone acetyltransferases (HATs). This increases the transcription of genes involved with inflammation or enrols histone deacetylases (HDACs) to down-regulate the transcription of inflammatory genes. These HATs and HDACs work in a homeostatic fashion; however, in the event of inflammation, increased HAT activity can stimulate further inflammation, which is believed to be the mechanism involved in some inflammatory diseases. This study hypothesises that in response to inflammation, the expression of HDACs (HDAC1-5) will decrease and the expression of HATs (NCOA1-3, HAT-1 and CREBBP) will increase in all groups. When comparing the expression between the groups, it was expected that a greater decrease in HDACs and a greater increase in HATs will be seen in the A-BD group compared to the other two groups. This would identify histone acetylation as a mechanism involved in the inflammatory condition of asthma and indicate that corticosteroids may treat the inflammation in asthma at least in part by controlling histone acetylation. The aim of the project was to compare the expression of inflammatory genes TFF1, TFF3, SCGB1A1 and SCGB3A2, as well as to compare the gene expression of HDAC1-5, NCOA1-3, HAT-1 and CREBBP within and between N-A (n=15), A-BD (n=15) and A-ST (n=15) groups in response to inflammation. This was performed by collecting airway cells and proteins by sputum induction in three sessions. The sessions were coordinated into an initial baseline collection (SI-1), followed by a second session at least one week later (SI-2) and a third session, six hours after SI-2 to collect a sample containing the resultant acute inflammation caused in SI-2 (SI-3). Analysis of the SI-1 and SI-2 samples in all three groups had high amounts of variability between samples. The samples were taken at least one weak apart and the environmental stimuli on each participant outside of the testing sessions could not be controlled. For this reason, the SI-1 samples were not used for analysis; instead SI-2 and SI-3 samples were compared as they were same-day collections, reducing the probability of differences being due to anything other than the sputum induction. The gene expressions of the TFFs, SCGBs, HDACs and HATs were analysed using real-time PCR. Western blot analysis was performed to analyse the protein concentrations of the TFFs and SCGBs in secreted fractions of the sputum collection. Both the secreted and intracellular protein fractions collected from the sputum inductions for pre- and post-inflammation (SI-2, SI-3) samples of the N-A and A-BD groups were analysed using a proteomic method called iTRAQ. This allowed the comparison of the change in protein expression as a result of airway inflammation in each group. This technique was used as a discovery method to identify novel proteins that are modulated by induced acute airway inflammation. Any proteins of interest would then be further validated and used for future research. Inflammation was achieved in the SI-3 samples of the N-A group with a 21% unit increase in % neutrophils compared to SI-2 (p=0.01). The N-A group had a marked 5.5-fold decrease in HDAC1 gene expression in SI-3 compared to SI-2 (p=0.03). No differences were seen in any of the TFFs, SCGBs or any of the rest of the HDACs and HATs. Western blot data did not display any significant changes in the protein levels of the TFFs and SCGBs analysed. However, non-significant analysis of the data displayed increases in TFF1 and TFF3, and decreases in SCGB1A1 and SCGB3A2 for the majority of SI-3 samples compared to SI-2. The A-BD group also presented a marked increase in neutrophils in the SI-3 samples compared to SI-2 (27% unit increase, p=0.04). The A-BD group had a significant increase in TFF3 and SCGB1A1 gene expression concomitant with induced acute airway inflammation. A 7.3-fold increase in TFF3 (p=0.05) in SI-3 indicated that TFF3 is linked to inflammation in asthmatics. A 2.8-fold increase in SCGB1A1 (p=0.03) indicated that this gene is also up-regulated, suggesting that this SCGB is expressed to try to combat induced acute airway inflammation. No significant changes were seen in any of the other genes analysed. Western blot data did not display any significant changes in the protein levels of the TFFs and SCGBs analysed. However, non-significant analysis of the data displayed an increase in TFF1 and TFF3, and a decrease in SCGB1A1 and SCGB3A2 in SI-3, similar to that seen in the N-A group. The A-ST group was different from the A-BD group, characterised by the use of inhaled corticosteroid medication to treat asthma symptoms. Inhaled corticosteroids are known to treat asthma symptoms through the control of inflammation. Therefore, it was expected that corticosteroid medication would also control the expression of TFFs, SCGBs, HATs and HDACs. Gene expression results only identified a 7.6-fold decrease in HDAC2 expression in SI-3 (p=0.001), which is proposed to be due to the up-regulation of HDAC2 protein that is known to be a function of corticosteroid use. Western blot data did not display any significant changes in the protein levels of the TFFs and SCGBs analysed. The gene expression in SI-2 and SI-3 in each group was compared. When comparing the A-BD group to the N-A group, a 9-fold increase in TFF3 (p=0.008) and a 34-fold increase in SCGB1A1 (p=0.03) were seen in the SI-3 samples. Comparisons of the A-ST group to the N-A group had an increased expression in SI-2 samples for HDAC5 (3.6-fold, p=0.04), NCOA2 (8.5-fold, p=0.04), NCOA3 (17-fold, p=0.01), HAT-1 (36-fold, p=0.003) and CREBBP (13-fold, p=0.001). The SI-3 samples in the A-ST group compared to the N-A group had increased expression for HDAC1 (6.4-fold, p=0.04), HDAC5 (5.2-fold, p=0.008), NCOA2 (9.6-fold, p=0.03), NCOA3 (16-fold, p=0.06), HAT-1 (41-fold, p<0.001) and CREBBP (31-fold, p=0.001). Comparisons of the A-ST group to the A-BD group had SI-2 increases in HDAC1 (3.8-fold, p=0.03), NCOA3 (4.5-fold, p=0.03), HAT-1 (5.3-fold, p=0.01) and CREBBP (23-fold, p=0.001), while SI-3 comparisons saw a decrease in HDAC2 (41-fold, p=0.008) and increases in HAT-1 (4.3-fold, p=0.003) and CREBBP (40-fold, p=0.001). Results showed that TFF3 and SCGB1A1 expression is higher in asthmatics than non-asthmatics and that histone acetylation is more active in the A-ST group than either the N-A or A-BD group, which suggests that histone acetylation activity may be positively correlated with asthma severity. The iTRAQ proteomic analysis of the secreted protein samples identified the SCGB1A1 protein and found it to be decreased in both the N-A and A-BD groups post-inflammation, but significantly so only in the A-BD group. Although no significant results were obtained from the western blot data, both groups displayed a decrease in SCGB1A1 concentration in SI-3 samples, suggesting a correlation with the proteomic data. Only 31 peptides were identified from the secreted samples. The intracellular iTRAQ analysis successfully identified 664 peptides, eight of which had differential expression in association with induced acute airway inflammation. Significant increases were seen in the A-BD group in SI-3 compared to SI-2 than in the N-A group in chloride intracellular channel protein 1, keratin-19, eosinophil cationic protein, calnexin, peroxiredoxin-5, and ATP-synthase delta subunit, while decreases were seen in cystatin-A and mucin-5AC. The iTRAQ analysis was only a discovery measure and further validation must be performed. In summary, the expression of TFFs and SCGBs differed between non-asthmatics and asthmatics. It is clear that TFF3 is active in the airway inflammation associated with asthma as indicated by an increase associated with inflammation in the A-BD group compared to the N-A group. Results for HDAC and HAT genes showed high HAT expression in the A-ST group compared to the N-A and A-BD groups, suggesting that histone acetyltransferases may be responsible for the characteristic unregulated inflammatory symptoms of asthmatics taking corticosteroids. Interestingly, corticosteroid medication did not seem to silence the expression of the analysed HAT genes, which indicates that corticosteroids may not control inflammation by direct regulation of HATs, but instead by competition, most probably with HDAC2 protein. As a discovery tool, iTRAQ is a potent method to both identify and compare the concentration of proteins between samples. The method is a powerful first step into the identification of novel proteins that are regulated in response to different treatments.

The role of intensity of interval training on fat oxidation and eating behaviour in overweight/obese men

The increasing prevalence of obesity in society has been associated with a number of atherogenic risk factors such as insulin resistance. Aerobic training is often recommended as a strategy to induce weight loss, with a greater impact of high-intensity levels on cardiovascular function and insulin sensitivity, and a greater impact of moderate-intensity levels on fat oxidation. Anaerobic high-intensity (supramaximal) interval training has been advocated to improve cardiovascular function, insulin sensitivity and fat oxidation. However, obese individuals tend to have a lower tolerance of high-intensity exercise due to discomfort. Furthermore, some obese individuals may compensate for the increased energy expenditure by eating more and/or becoming less active. Recently, both moderate- and high-intensity aerobic interval training have been advocated as alternative approaches. However, it is still uncertain as to which approach is more effective in terms of increasing fat oxidation given the issues with levels of fitness and motivation, and compensatory behaviours. Accordingly, the objectives of this thesis were to compare the influence of moderate- and high-intensity interval training on fat oxidation and eating behaviour in overweight/obese men. Two exercise interventions were undertaken by 10-12 overweight/obese men to compare their responses to study variables, including fat oxidation and eating behaviour during moderate- and high-intensity interval training (MIIT and HIIT). The acute training intervention was a methodological study designed to examine the validity of using exercise intensity from the graded exercise test (GXT) - which measured the intensity that elicits maximal fat oxidation (FATmax) - to prescribe interval training during 30-min MIIT. The 30-min MIIT session involved 5-min repetitions of workloads 20% below and 20% above the FATmax. The acute intervention was extended to involve HIIT in a cross-over design to compare the influence of MIIT and HIIT on eating behaviour using subjective appetite sensation and food preference through the liking and wanting test. The HIIT consisted of 15-sec interval training at 85 %VO2peak interspersed by 15-sec unloaded recovery, with a total mechanical work equal to MIIT. The medium term training intervention was a cross-over 4-week (12 sessions) MIIT and HIIT exercise training with a 6-week detraining washout period. The MIIT sessions consisted of 5-min cycling stages at ±20% of mechanical work at 45 %VO2peak, and the HIIT sessions consisted of repetitive 30-sec work at 90 %VO2peak and 30-sec interval rests, during identical exercise sessions of between 30 and 45 mins. Assessments included a constant-load test (45 %VO2peak for 45 mins) followed by 60-min recovery at baseline and the end of 4-week training, to determine fat oxidation rate. Participants’ responses to exercise were measured using blood lactate (BLa), heart rate (HR) and rating of perceived exertion (RPE) and were measured during the constant-load test and in the first intervention training session of every week during training. Eating behaviour responses were assessed by measuring subjective appetite sensations, liking and wanting and ad libitum energy intake. Results of the acute intervention showed that FATmax is a valid method to estimate VO2 and BLa, but is not valid to estimate HR and RPE in the MIIT session. While the average rate of fat oxidation during 30-min MIIT was comparable with the rate of fat oxidation at FATmax (0.16 ±0.09 and 0.14 ±0.08 g/min, respectively), fat oxidation was significantly higher at minute 25 of MIIT (P≤0.01). In addition, there was no significant difference between MIIT and HIIT in the rate of appetite sensations after exercise, but there was a tendency towards a lower rate of hunger after HIIT. Different intensities of interval exercise also did not affect explicit liking or implicit wanting. Results of the medium-term intervention indicated that current interval training levels did not affect body composition, fasting insulin and fasting glucose. Maximal aerobic capacity significantly increased (P≤0.01) (2.8 and 7.0% after MIIT and HIIT respectively) during GXT, and fat oxidation significantly increased (P≤0.01) (96 and 43% after MIIT and HIIT respectively) during the acute constant-load exercise test. RPE significantly decreased after HIIT greater than MIIT (P≤0.05), and the decrease in BLa was greater during the constant-load test after HIIT than MIIT, but this difference did not reach statistical significance (P=0.09). In addition, following constant-load exercise, exercise-induced hunger and desire to eat decreased after HIIT greater than MIIT but were not significant (p value for desire to eat was 0.07). Exercise-induced liking of high-fat sweet (HFSW) and high-fat non-sweet (HFNS) foods increased after MIIT and decreased after HIIT (p value for HFNS was 0.09). The intervention explained 12.4% of the change in fat intake (p = 0.07). This research is significant in that it confirmed two points in the acute study. While the rate of fat oxidation increased during MIIT, the average rate of fat oxidation during 30-min MIIT was comparable with the rate of fat oxidation at FATmax. In addition, manipulating the intensity of acute interval exercise did not affect appetite sensations and liking and wanting. In the medium-term intervention, constant-load exercise-induced fat oxidation significantly increased after interval training, independent of exercise intensity. In addition, desire to eat, explicit liking for HFNS and fat intake collectively confirmed that MIIT is accompanied by a greater compensation of eating behaviour than HIIT. Findings from this research will assist in developing exercise strategies to provide obese men with various training options. In addition, the finding that overweight/obese men expressed a lower RPE and decreased BLa after HIIT compared with MIIT is contrary to the view that obese individuals may not tolerate high-intensity interval training. Therefore, high-intensity interval training can be advocated among the obese adult male population. Future studies may extend this work by using a longer-term intervention.

Study protocol : establishing good relationships between patients and health care providers while providing cardiac care. Exploring how patient-clinician engagement contributes to health disparities between indigenous and non-indigenous Australians in South Australia

Abstract Background: Studies that compare Indigenous Australian and non-Indigenous patients who experience a cardiac event or chest pain are inconclusive about the reasons for the differences in-hospital and survival rates. The advances in diagnostic accuracy, medication and specialised workforce has contributed to a lower case fatality and lengthen survival rates however this is not evident in the Indigenous Australian population. A possible driver contributing to this disparity may be the impact of patient-clinician interface during key interactions during the health care process. Methods/Design: This study will apply an Indigenous framework to describe the interaction between Indigenous patients and clinicians during the continuum of cardiac health care, i.e. from acute admission, secondary and rehabilitative care. Adopting an Indigenous framework is more aligned with Indigenous realities, knowledge, intellects, histories and experiences. A triple layered designed focus group will be employed to discuss patient-clinician engagement. Focus groups will be arranged by geographic clusters i.e. metropolitan and a regional centre. Patient informants will be identified by Indigenous status (i.e. Indigenous and non-Indigenous) and the focus groups will be convened separately. The health care provider focus groups will be convened on an organisational basis i.e. state health providers and Aboriginal Community Controlled Health Services. Yarning will be used as a research method to facilitate discussion. Yarning is in congruence with the oral traditions that are still a reality in day-to-day Indigenous lives. Discussion: This study is nestled in a larger research program that explores the drivers to the disparity of care and health outcomes for Indigenous and non-Indigenous Australians who experience an acute cardiac admission. A focus on health status, risk factors and clinical interventions may camouflage critical issues within a patient-clinician exchange. This approach may provide a way forward to reduce the appalling health disadvantage experienced within the Indigenous Australian communities. Keywords: Patient-clinician engagement, Qualitative, Cardiovascular disease, Focus groups, Indigenous

Postpartum care for Aboriginal and non-Aboriginal women with Gestational Diabetes Mellitus across urban, rural and remote locations : a protocol for a cohort linkage study

Background: Gestational diabetes mellitus (GDM) is increasing, along with obesity and type 2 diabetes (T2DM), with Aboriginal and Torres Strait Islander people* in Australia particularly affected. GDM causes serious complications in pregnancy, birth, and the longer term, for both women and their infants. Women diagnosed with GDM have an eightfold risk of developing T2DM after pregnancy, compared with women who have not had GDM. Indigenous women have an even higher risk, at a younger age, and progress more quickly from GDM to T2DM, compared to non-Indigenous women. If left undetected and untreated, T2DM can lead to heart disease, stroke, renal disease, kidney failure, amputations and blindness. A GDM diagnosis offers a ‘window of opportunity’ for diabetes health interventions and it is vital that acceptable and effective prevention, treatment, and post-pregnancy care are provided. Low rates of post-pregnancy screening for T2DM are reported among non-Aboriginal women in Australia and among Indigenous women in other countries, however data for Aboriginal women are scarce. Breastfeeding, a healthy diet, and exercise can also help to prevent T2DM, and together with T2DM screening are recommended elements of ‘post-pregnancy care’ for women with GDM, This paper describes methods for a data linkage study to investigate rates of post-pregnancy care among women with GDM. Methods/Design: This retrospective cohort includes all women who gave birth at Cairns Base Hospital in Far North Queensland, Australia, from 2004 to 2010, coded as having GDM in the Cairns Base Hospital Clinical Coding system. Data linkage is being conducted with the Queensland Perinatal Data Collection, and three laboratories. Hospital medical records are being reviewed to validate the accuracy of GDM case ascertainment, and gather information on breastfeeding and provision of dietary advice. Multiple logistic regression is being used to compare post-pregnancy care between Aboriginal and non-Aboriginal women, while adjusting for other factors may impact on post-pregnancy care. Survival analysis is being used to estimate the rates of progression from GDM to T2DM. Discussion: There are challenges to collecting post-pregnancy data for women with GDM. However, research is urgently needed to ensure adequate post-pregnancy care is provided for women with GDM in Australia.

Consumer engagement with eHealth information through smartphones and tablets : an Australian perspective

This paper is a work in progress that examines current consumer engagement with eHealth information through Smartphones or tablets. We focus on three activity types: seeking, posting and ‘other’ engagement activity and compare two age groups, 25-40s and over 40-55s. Findings show that around 30% of the younger age group is engaging with Government and other Health providers’ websites, receiving eHealth emails, and reading other people’s comments about health related issues in online discussion groups/websites/blog. Approximately 20% engage with Government and other Health providers’ social media and watch or listen to audio or video podcasts. For the older age group, their most active engagement with eHealth information is in the seeking category through Government or other health websites (approximately 15%), and less than 10% for social media sites. Their posting activity is less than 5%. Other activities show that less than 15% of the older age group engages through receiving emails and reading blogs, less than 10% watch or listen to podcasts, and their online consulting activity is less than 7%. We note that scores are low for both groups in terms of engaging with eHealth information through Twitter.