Exposure estimation, uncertainty and variability in occupational hygiene retrospective assessment

This thesis reports on a quantitative exposure assessment and on an analysis of the attributes of the data used in the estimations, in particular distinguishing between its uncertainty and variability. A retrospective assessment of exposure to benzene was carried out for a case control study of leukaemia in the Australian petroleum industry. The study used the mean of personal task-based measurements (Base Estimates) in a deterministic algorithm and applied factors to model back to places, times etc for which no exposure measurements were available. Mean daily exposures were estimated, on an individual subject basis, by summing the task-based exposures. These mean exposures were multiplied by the years spent on each job to provide exposure estimates in ppm-years. These were summed to provide a Cumulative Estimate for each subject. Validation was completed for the model and key inputs. Exposures were low, most jobs were below TWA of 5 ppm benzene. Exposures in terminals were generally higher than at refineries. Cumulative Estimates ranged from 0.005 to 50.9 ppm-years, with 84 percent less than 10 ppm-years. Exposure probability distributions were developed for tanker drivers using Monte Carlo simulation of the exposure estimation algorithm. The outcome was a lognormal distribution of exposure for each driver. These provide the basis for alternative risk assessment metrics e.g. the frequency of short but intense exposures which provided only a minimal contribution to the long-term average exposure but may increase risk of leukaemia. The effect of different inputs to the model were examined and their significance assessed using Monte Carlo simulation. The Base Estimates were the most important determinant of exposure in the model. The sources of variability in the measured data were examined, including the effect of having censored data and the between and within-worker variability. The sources of uncertainty in the exposure estimates were analysed and consequential improvements in exposure assessment identified. Monte Carlo sampling was also used to examine the uncertainties and variability associated with the tanker drivers' exposure assessment, to derive an estimate of the range and to put confidence intervals on the daily mean exposures. The identified uncertainty was less than the variability associated with the estimates. The traditional approach to exposure estimation typically derives only point estimates of mean exposure. The approach developed here allows a range of exposure estimates to be made and provides a more flexible and improved basis for risk assessment.

Occupational health and safety management systems : system types and effectiveness

The aim of this thesis is to develop a framework to evaluate the relative performance of different types of health and safety management system. This objective is an analytical one, but it stems from a policy issue of public importance. Over the past decade Australia, like other countries, has seen the emergence and growth of interest in developing health and safety management systems. But are they all the same, and if not, do they differ in their effectiveness? The thesis does not seek to give a definitive answer to these questions. Given the novelty of the phenomenon and the lack of research on this subject, the research is exploratory. An hypothesis about the effectiveness of different health and safety management systems is developed rather than tested. The thesis proceeds by first defining health and safety management systems as a combination of the planning and review, the management arrangements, the consultative arrangements and the specific program elements that work together in an integrated way to improve health and safety performance. A research procedure is described involving twenty exploratory case studies. The thesis then - develops - from the literature and the case study research - an analytical framework to evaluate the performance of different health and safety management systems. That framework has two parts. First is a typology of health and safety management systems. This is constructed from two distinctions - between 'safe place' and 'safe person' approaches to health and safety; and between 'innovative' and traditional' management methods and structures. These distinctions yield four types of system. The typology was applied to the case studies which yielded a reasonable fit in most instances. The second part of the framework is a 'process evaluation' technique akin to Quality standards. Derived from the Victorian SafetyMAP audit criteria, the "e;process evaluation tool "e; is preferred to traditional outcome measures such as incident or claim rates. Using this measure, the twenty case study enterprises were classified as above average, average or below average in performance. These results correlated poorly with traditional incident trend and benchmark measures. The two elements of the framework are then combined to explore the relationship between the different types of system and their performance. Evidence from the twenty case studies showed a tendency for innovative/safe place firms to perform better than traditional/safe person firms. This finding can form the basis for a hypothesis that may be subject to statistical testing on a generalisable sample. In addition five 'best practice' cases were selected and subjected to a cross case analysis to search for common characteristics that might explain their performance. This analysis suggests the importance of a number of factors: senior managers who drive health and safety change and mobilise all possible resources in the pursuit of change; health and safety representatives who work with managers in a 'joint regulatory relationship' across system activities; the involvement of employees more generally, but not as a substitute for action by managers and health and safety representatives; a comprehensive approach to elimination of all hazards; and the introduction of innovative programs to continually improve systems and facilitate employee involvement in health and safety.

Occupational therapists and the use of constraint-induced movement therapy in neurological practice

There is adaquate evidence for supporting the use of constraint-induced movement therapy (CIMT) in post-stroke rehabilitation. However, the actual usage of CIMT in routine occupational therapy practice appears limited. Further research is required to study why this might be so.

Management of cardiovascular diseases with micro systems and nanotechnology

Cardiovascular diseases are the leading cause of death and morbidity in industrialized nations and are becoming an urgent health problem for all nations due to the unstoppable trend of an ageing and obese population. Due to the rapid development of micro total analysis systems (μTAS) and nanotechnology in recent years, they will play an important role in the diagnosis, management, and therapy of cardiovascular diseases. It is envisaged that the micro and nanotechnologies developed for treating other diseases shall be explored for cardiovascular applications to reduce the research effort required for commercializing the devices and drugs to meet the increasing demand of the cardiovascular patients.

Application of the psychological contract to occupational safety

Psychological contracts were applied to occupational safety. A psychological contract of safety measure was developed and validated, and a model of safety developed to investigate breach and fulfilment of the psychological contract of safety. Findings suggest that the psychological contract of safety impacts safety attitudes and safety behaviour.

Safer injections, fewer infections : management of needles and sharps and occupational blood exposure in rural north Indian health settings

This study investigated injection practices and occupational exposure to blood in rural north Indian health settings. The findings highlighted a range of practices potentially contributing to the transmission of hepatitis and HIV to both patients and staff in these settings. Interventions need to focus on the development of organisational structures to support and facilitate safer practices.

Promises of nanotechnology for drug delivery to brain in neurodegenerative diseases

Brain is a delicate organ, isolated from general circulation and characterized by the presence of relatively impermeable endothelial cells with tight junctions, enzymatic activity and the presence of active efflux transporter mechanisms. These formidable obstacles often block drug delivery to the brain across the blood-brain barrier (BBB). Although several promising molecules have the potential in the in vitro settings but lack of in vivo response is probably because the molecule cannot reach the brain in a sufficient concentration. Drug delivery across the BBB is a major limitation in the treatment of central nervous system (CNS) disorders and CNS infections. This review deals with the role of nanobiotechnology in CNS drug delivery, in which three categories of carbon nanotubes, nanowires and nanoparticles (NPs) are explained. The small size of the NPs makes them an ideal choice to penetrate the BBB. Several mechanisms are involved in this process and various strategies are used. There are some concerns about the safety of NP entry in the brain that need to be resolved before human use. Although there is no approved nanotechnology-based CNS drug available the future for such neuro-nanobiotechnology based delivery system developments is promising.

A grounded theory of intuition among occupational therapists in mental health practice

Objectives: This study aimed to explore occupational therapists’ understanding and use of intuition in mental health practice.
Method: Using a grounded theory approach, a theoretical sample of nine occupational therapists practising in mental health settings participated in semi-structured interviews. Data were analysed using the constant comparative method.
Findings: Intuition was found to be embedded within clinical reasoning. From the data, intuition was defined as knowledge without conscious awareness of reasoning. The participants viewed intuition as elusive and underground, and suggested that professional experience led to a more comfortable use of intuition. Using intuition relied on therapists’ understanding of their own and others’ emotions, and intuition partnered analysis within their clinical reasoning. A grounded theory of the use of intuition in mental health settings is proposed.
Conclusion: Occupational therapists practising in mental health settings understand intuition to be an instinctive understanding of situations, resulting from their professional experience and the understanding of emotions.

Applications of aptamers in nanodelivery systems in cancer, eye and inflammatory diseases

Aptamers are an interesting class of molecules that have potential in many facets of human health. They are characterized by high affinity and specificity to their targets, are small in size, have similar properties to antibodies, but are made synthetically. All of these properties, among others, give aptamers the potential to diagnose, image and treat like no other molecules. By combining the unique properties of aptamers with the ever expanding field of nanotechnology and all it has to offer, we are entering a very promising new area of targeted nanodelivery treatments. These treatments have found success in the complex disease processes of cancer, eye and inflammatory diseases.