Review of preventative behavioural interventions for dermal and respiratory hazards

BACKGROUND

No previous systematic review of the evidence base has been undertaken to help occupational health professionals understand how to reliably lower the instance of occupational ill-health through reducing risk-taking behaviour.

AIMS

To evaluate the effectiveness and processes of occupational-based behavioural interventions for workers exposed to dermal and respiratory hazards.

METHODS

A systematic review was conducted. Sixteen electronic databases were searched using key words. Bibliography, health and safety websites and hand searches of key journals were also undertaken. Articles were included if they evaluated an intervention targeting workers' behavioural compliance, addressed dermal or respiratory hazards, used before and after measures with a control group comparison and used behaviour-related exposure indicators such as airborne exposure, health effects, behaviour observations and self-reported work practices. Data were extracted according to potential sources of bias, impact and behavioural change processes used.

RESULTS

Ten of 550 articles identified as potentially relevant were included. A predominance of small effect sizes, particularly for larger samples, demonstrated limited but positive impact upon exposure. Studies contained too much heterogeneity for reliable meta-analysis. None of the studies covered the full range of behaviour change components necessary for reducing exposure risk.

CONCLUSIONS

We conclude that future interventions could enhance their effectiveness through improving design quality, reporting and basing their content upon evidence-based behavioural change approaches. Using a comprehensive range of evidence-informed behaviour change ingredients should improve occupational health professional's ability to reliably reduce occupational ill-health where exposure cannot totally be designed out of the workplace.

Information in magnetic resonance images: evaluation of signal, noise and contrast

The assessment of diagnostic image quality for MRI is considered. The assessment of three key image quality determinants is addressed: signal, noise and contrast. There is a distinction between random noise evaluation, for the calculation of the SNR, and structured noise evaluation for the assessment of image artefacts. Specific methods used are correlation techniques and the Wiener spectrum. Contrast is assessed by comparison of experimental data and theoretical predictions. For each assessment, the theory and method of the evaluation strategy are discussed. The discussion is illustrated with analysis results from commercial MR systems. The choice of analysis method and the subsequent derivation of quality indices are shown to be critical in respect of robustness and accuracy.

The modification of the RF field distribution of surface coils by weakly conducting saline samples

The modification of the RF field distribution of a surface coil, which is brought about by both loading and skin effect conditions arising from the proximity of weakly conducting saline samples, is demonstrated. A procedure for the calibration of the depth of the spectral acquisition region in depth-pulse localized in vivo spectroscopy is shown to be acceptable.

An evaluation of the effect of fasting on the exercise-induced changes in pH and Pi/PCr from skeletal muscle

The changes in the response of skeletal muscle to maximal dynamic exercise were investigated in going from a fasted state to a refed state by means of 31P NMR spectroscopy. It was found that in the fasted state, exercise-induced changes in Pi/PCr and in pH were both inhibited, in comparison with those in the refed state.

Covalent binding of a fluorinated 2-nitroimidazole to EMT-6 tumors in Balb/C mice: detection by F-19 nuclear magnetic resonance at 2.35 T

A hexafluorinated 2-nitroimidazole (CCI-103F) has been synthesized and its properties as a hypoxic cell binder investigated. The drug has a plasma half-life of 90 min in Balb/C mice and a tumor-to-plasma ratio of 0.8. Following sustained exposure to the drug and a washout period for the unbound drug, liver and tumor samples were excised. NMR investigation of the excised tissue in a 2.35 T animal sized NMR facility revealed the presence of 19F bound to both tissues. Further improvement in sensitivity is required to make 19F NMR detection of binding in situ feasible.

A proton NMR relaxation evaluation of a model of brain oedema fluid

Using CSF/protein solutions as models of vasogenic extracellular fluid, the concentration dependences of longitudinal and transverse proton relaxation rates have been measured at 37 degrees C and 100 MHz for the serum proteins, albumin, IgG, a 2.8:1 mixture of albumin and IgG and human serum itself. These measurements have been used to determine the sensitivity of proton relaxation rates to the amount and the type of the protein in oedema fluid, and to establish the significance of both of these factors in relation to a separation of vasogenic from cytotoxic oedema. An extension of the two-environment rapid-exchange model of solvent relaxation is presented, which accounts for the measurements on protein mixtures and which enables estimates to be made of the number and the transverse relaxation rate of water protons associated with the protein surface.

The influence of oxygenation on the 19F spin-lattice relaxation rates of fluosol-DA

The spin-lattice relaxation rates (1/T1) were measured at 94.1 MHz for six peaks in the 19F NMR spectrum of the perfluorochemical blood substitute fluosol-DA, which contains a mixed emulsion of perfluorodecalin and perfluorotripropylamine. Each of these rates increased linearly with the percentage of oxygen dissolved in the emulsion. Relative values of the linear increase for different peaks established that, for perfluorotripropylamine in the mixed emulsion, the oxygen-fluorocarbon interaction is loosely but preferentially oriented in a manner similar to that previously established for other pure fluorocarbons. The uncertainty in the oxygen level estimated from T1 measurements is somewhat less than 5% O2 and it is thus established that quantitative non-invasive oxygenation measurements can be made to sufficient precision by this approach, using fluosol-DA and 19F spin-lattice relaxation.