Exploring two-dimensional chromatography and chemiluminescence selectivity for complex sample analysis

 Human, animal and plant samples contain a considerable number of chemical substances critical for supporting their existence. This thesis presents improved techniques to find and analyse these components to help us understand more about their roles in the complex jigsaw of life.

Brief report: associations between self-reported paternal relationships, anger, alcohol, and intimate partner violence in a prison sample

This study investigates the association between family relationships, anger, alcohol use, and self-reported intimate partner violence (IPV). Participants were 55 male prisoners who completed a survey about their family relationships, anger, alcohol use, and aggression. Exposure to parental IPV predicted rates of self-reported perpetration of IPV, suggesting the importance of understanding more about the developmental pathways to IPV if effective prevention, intervention, and assessment strategies are to be developed for use with this high-risk population.

Individual, occupational, and workplace correlates of occupational health and safety vulnerability in a sample of Canadian workers

Objective: To describe OH&S vulnerability across a diverse sample of Canadian workers.
Methods: A survey was administered to 1,835 workers employed more than 15 hrs/week in workplaces with at least five employees. Adjusted logistic models were fitted for three specific and one overall measure of workplace vulnerability developed based on hazard exposure and access to protective OH&S policies and procedures, awareness of employment rights and responsibilities, and workplace empowerment.
Results: More than one third of the sample experienced some OH&S vulnerability. The type and magnitude of vulnerability varied by labor market sub-group. Younger workers and those in smaller workplaces experienced signficantly higher odds of multiple types of vulnerability. Temporary workers reported elevated odds of overall, awareness- and empowerment-related vulnerability, while respondents born outside of Canada had significantly higher odds of awareness vulnerability.
Conclusion: Knowing how labor market sub-groups experience different types of vulnerability can inform better-tailored primary prevention interventions.

Co-ingestion of energy drinks with alcohol and other substances among a sample of people who regularly use ecstasy

INTRODUCTION AND AIMS: Despite the potential harms of mixing unregulated drugs with energy drinks (ED), research to date has primarily been focused on EDs co-ingested with alcohol. Consequently, the aim of the present study was to explore the rate of use, harms and correlates of EDs co-ingested with alcohol and other drugs among a sample of people who regularly use illicit stimulant drugs. DESIGN AND METHODS: In 2010, 693 Australians who regularly used ecstasy completed a 1-h interview about their past six-month ED and drug use. RESULTS: Three-quarters of the sample (77%) had recently consumed EDs with other substances, primarily alcohol (70%) and ecstasy (57%). People who consumed ED with alcohol versus those who had consumed ED with ecstasy and with alcohol (only 8% reported only consuming ED with ecstasy) had similar profiles in regards to demographics, drug use, mental health and drug-related problems. Primary motives for consuming ED with alcohol included increased alertness (59%), the taste (25%), to party for longer (23%) and to combat fatigue (16%). One-half (52%) and one-quarter (27%) of participants who consumed EDs with alcohol and with ecstasy respectively had recently experienced adverse outcomes post-consumption, primarily headaches (24% and 11%) and heart palpitations (21% and 14%). DISCUSSION AND CONCLUSIONS: Co-ingestion of EDs with licit and illicit drugs is common among people who regularly use ecstasy and related drugs. Adverse outcomes of co-ingestion suggest that targeted education regarding negative interactive drug effects is crucial for harm reduction. [Peacock A, Sindicich N, Dunn M, Whittaker E, Sutherland R, Entwistle G, Burns L, Bruno R. Co-Ingestion of Energy Drinks with Alcohol and Other Substances among a Sample of People Who Regularly Use Ecstasy. Drug Alcohol Rev 2015].

Maternal dietary intake and physical activity habits during the postpartum period: associations with clinician advice in a sample of Australian first time mothers

BACKGROUND: Numerous health benefits are associated with achieving optimal diet and physical activity behaviours during and after pregnancy. Understanding predictors of these behaviours is an important public health consideration, yet little is known regarding associations between clinician advice and diet and physical activity behaviours in postpartum women. The aims of this study were to compare the frequency of dietary and physical activity advice provided by clinicians during and after pregnancy and assess if this advice is associated with postpartum diet and physical activity behaviours.

METHODS: First time mothers (n = 448) enrolled in the Melbourne InFANT Extend trial completed the Cancer Council of Australia's Food Frequency Questionnaire when they were three to four months postpartum, which assessed usual fruit and vegetable intake (serves/day). Total physical activity time, time spent walking and time in both moderate and vigorous activity for the previous week (min/week) were assessed using the Active Australia Survey. Advice received during and following pregnancy were assessed by separate survey items, which asked whether a healthcare practitioner had discussed eating a healthy diet and being physically active. Linear and logistic regression assessed associations of advice with dietary intake and physical activity.

RESULTS: In total, 8.6 % of women met guidelines for combined fruit and vegetable intake. Overall, mean total physical activity time was 350.9 ± 281.1 min/week. Time spent walking (251.97 ± 196.78 min/week), was greater than time spent in moderate (36.68 ± 88.58 min/week) or vigorous activity (61.74 ± 109.96 min/week) and 63.2 % of women were meeting physical activity recommendations. The majority of women reported they received advice regarding healthy eating (87.1 %) and physical activity (82.8 %) during pregnancy. Fewer women reported receiving healthy eating (47.5 %) and physical activity (51.9 %) advice by three months postpartum. There was no significant association found between provision of dietary and/or physical activity advice, and mother's dietary intakes or physical activity levels.

CONCLUSIONS: Healthy diet and physical activity advice was received less after pregnancy than during pregnancy yet no association between receipt of advice and behaviour was observed. More intensive approaches than provision of advice may be required to promote healthy diet and physical activity behaviours in new mothers.

Dietary sources and sodium intake in a sample of Australian preschool children

OBJECTIVES: To assess dietary sodium intake and the food sources of sodium in a sample of Australian preschool children. DESIGN: Cross-sectional. SETTING: Mothers were followed up when children were approximately 3.5 years of age after participating in a cluster randomised controlled trial: the Melbourne Infant Feeding Activity and Nutrition Trial Program. PARTICIPANTS: 251 Australian children aged 3.5±0.19 (SD) years. PRIMARY AND SECONDARY OUTCOME MEASURES: The average daily sodium intake was determined using three unscheduled 24 h dietary recalls. The contributions of food groups, core, discretionary and processed foods to daily sodium intake were assessed. RESULTS: The average sodium intake was 1508±495 (SD) mg/day, (salt equivalent 3.9±1.3 (SD) g/day) and 87% of children exceeded the Australian Upper Level of Intake (UL) for sodium of 1000 mg/day (salt equivalent 2.6 g/day). Main food sources of sodium were cereal/cereal products (25%), milk products (19%), meat, poultry/game (17%) and cereal-based products (15%). Core foods contributed 65%, and discretionary foods 35% of total daily sodium intake, and within the total diet, minimally processed, processed, processed culinary ingredient and ultraprocessed foods contributed 16%, 35%, 1% and 48% of sodium, respectively. CONCLUSIONS: Within this sample, most children exceeded the recommended UL for sodium. Core and ultraprocessed foods were key sources of sodium which suggests that reductions in the sodium content of these foods are required to reduce sodium intake in young children. These data also provide further support for public health campaigns that seek to reduce consumption of energy-dense, nutrient-poor foods.

Multiple task transfer learning with small sample sizes

Prognosis, such as predicting mortality, is common in medicine. When confronted with small numbers of samples, as in rare medical conditions, the task is challenging. We propose a framework for classification with data with small numbers of samples. Conceptually, our solution is a hybrid of multi-task and transfer learning, employing data samples from source tasks as in transfer learning, but considering all tasks together as in multi-task learning. Each task is modelled jointly with other related tasks by directly augmenting the data from other tasks. The degree of augmentation depends on the task relatedness and is estimated directly from the data. We apply the model on three diverse real-world data sets (healthcare data, handwritten digit data and face data) and show that our method outperforms several state-of-the-art multi-task learning baselines. We extend the model for online multi-task learning where the model parameters are incrementally updated given new data or new tasks. The novelty of our method lies in offering a hybrid multi-task/transfer learning model to exploit sharing across tasks at the data-level and joint parameter learning.

Knowledge of glaucoma, and its relationship to self-care practices, in a population sample

OBJECTIVE: To determine the level of knowledge of glaucoma in a population-based sample, and its relationship to self-care practices.

DESIGN AND SUBJECTS: A cluster random sample of the Melbourne population 40 years of age and older was interviewed. One thousand seven hundred and eleven residents living in five randomly selected Melbourne metropolitan suburbs, each consisting of two adjacent census collector districts.

MEASURES: Questions were asked concerning respondents' awareness, knowledge and description of the disease. Respondents were also asked the year of their last visit to their eye health care provider.

RESULTS: Seventy per cent of the sample had heard of glaucoma. However, only 22% provided a description that demonstrated a reasonable understanding of the disease. A lack of awareness and knowledge of glaucoma appeared to be negatively related to self-care practices.

CONCLUSION: Serious deficiencies in the basic knowledge of glaucoma in the community was demonstrated. This has significant public health implications as only a small percentage of the at-risk population may present themselves for assessment and treatment. Informing the community about glaucoma is an important step in promoting preventative ophthalmic care and reducing visual impairment and blindness.

24-h urinary sodium excretion is associated with obesity in a cross-sectional sample of Australian schoolchildren

Emerging evidence indicates that dietary Na may be linked to obesity; however it is unclear whether this relationship is independent of energy intake (EI). The aim of this study was to assess the association between Na intake and measures of adiposity, including BMI z score, weight category and waist:height ratio (WHtR), in a sample of Australian schoolchildren. This was a cross-sectional study of schoolchildren aged 4-12 years. Na intake was assessed via one 24-h urine collection. BMI was converted to age- and sex-specific z scores, and WHtR was used to define abdominal obesity. In children aged ≥8 years, EI was determined via one 24-h dietary recall. Of the 666 children with valid urine samples 55 % were male (average age 9·3 (sd 1·8) years). In adjusted models an additional 17 mmol/d of Na was associated with a 0·10 higher BMI z score (95 % CI 0·07, 0·13), a 23 % (OR 1·23; 95 % CI 1·16, 1·31) greater risk of being overweight/obese and a 15 % (OR 1·15; 95 % CI 1·09, 1·23) greater risk of being centrally obese. In the subsample of 8-12-year-old children (n 458), adjustment for EI did not markedly alter the associations between Na and adiposity outcomes. Using a robust measure of daily Na intake we found a positive association between Na intake and obesity risk in Australian schoolchildren, which could not be explained by total energy consumption. To determine whether this is a causal relationship, longitudinal studies, with high-quality measures of Na and EI, are required.

Sleep duration and risk of obesity among a sample of Victorian school children

BACKGROUND: Insufficient sleep is potentially an important modifiable risk factor for obesity and poor physical activity and sedentary behaviours among children. However, inconsistencies across studies highlight the need for more objective measures. This paper examines the relationship between sleep duration and objectively measured physical activity, sedentary time and weight status, among a sample of Victorian Primary School children.

METHODS: A sub-sample of 298 grades four (n = 157) and six (n = 132) Victorian primary school children (aged 9.2-13.2 years) with complete accelerometry and anthropometry data, from 39 schools, were taken from a pilot study of a larger state based cluster randomized control trial in 2013. Data comprised: researcher measured height and weight; accelerometry derived physical activity and sedentary time; and self-reported sleep duration and hypothesised confounding factors (e.g. age, gender and environmental factors).

RESULTS: Compared with sufficient sleepers (67 %), those with insufficient sleep (<10 hrs/day) were significantly more likely to be overweight (OR 1.97, 95 % CI:1.11-3.48) or obese (OR 2.43, 95 % CI:1.26-4.71). No association between sleep and objectively measured physical activity levels or sedentary time was found.

CONCLUSION: The strong positive relationship between weight status and sleep deprivation merits further research though PA and sedentary time do not seem to be involved in the relationship. Strategies to improve sleep duration may help obesity prevention initiatives in the future.