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Biomedical subjects

A Broadhurst

Publications and source records attributed to A Broadhurst.

11 recordsLinked to original sources
PubMed2004

Determination of depth-dependent diffraction data: a new approach.

A direct method for determining powder diffraction data at specific depths from angle-dependent diffraction data is described. The method is non-destructive and only traditional data collections, where the angle of incidence is varied, are required. These angle-dependent spectra are transformed to give diffraction data arising from different depths, which may then be exploited using any conventional method. This is a novel approach as traditional methods are forced to tolerate the inherent depth averaging of grazing-angle diffraction, or only examine specific structural characteristics. In order to obtain depth-dependent X-ray diffraction data, a Fredholm integral equation of the first kind is solved using regularization techniques. The method has been validated by the generation of pseudo-experimental data having known depth profiles and solving the Fredholm integral equation to recover the solution. The method has also been applied to experimental data from a number of thin film systems.

Journal Article↗
PubMed1994

Acceleration perturbations of daily living. A comparison to 'whiplash'.

STUDY DESIGN: This study measured repeated human head accelerations (g) during daily activities. OBJECTIVES: Perturbations of daily living were compared to similar data from low velocity rear-end motor vehicle accidents. SUMMARY OF BACKGROUND DATA: Past assumptions suggest that motor vehicle accident severity does not correlate with the degree of sustained injury. Early engineering studies indicated that occupant disturbance in a low velocity motor vehicle accident is minor. METHODS: Eight volunteers were perturbed with 13 daily activities. Helmets on the heads of volunteers were instrumented with tri-planar accelerometers with output sampling of 500 Hz, sensitivity of 0.02 g, and a range of +/- 20 g. RESULTS: There was wide inter-subject response for various perturbations. Plopping backward into a chair caused maximum peak acceleration horizontally at 5.6 g and vertically at 8.5 g, with force vector of 10.1 g at 54.9 degrees. Mean impulse duration was 0.19 sec. There was no hint of injury in any subject. CONCLUSIONS: Perturbations of daily living compared similarly to the jostling expected in low velocity "whiplash"-type motor vehicle accidents.

Acceleration↗
PubMed1988

Dietary and other characteristics relevant for coronary heart disease in men of Indian, West Indian and European descent in London.

The origins of the high standardized mortality ratio (SMR) for coronary heart disease (CHD) among Indians in Britain, and the low SMR for West Indian immigrants, have been explored by a community survey in London. Serum lipoproteins, plasma glucose, haemostatic factors and other putative risk characteristics were measured in 75 Indian, 64 European and 24 West Indian men aged 45-54 years. These represented 81% of men registered with a general practice and resident within a defined area. In 51 men, diet was assessed by 5-day weighed inventory. Plasma phospholipid fatty acids (PFA) were measured in 18 Indians and 19 Europeans with dietary records. The relatively high HDL and HDL2-cholesterol concentrations, low LDL-cholesterol concentration, reduced fat intake, increased ratio of dietary polyunsaturated/saturated fat, relatively frequent use of alcohol, and lack of obesity in West Indians accorded with their low SMR from CHD. By contrast, only the relatively low HDL and HDL2-cholesterol concentrations, infrequency of alcohol consumption, and lower proportion of PFA as n-3 fatty acids of marine origin afforded explanations for the high SMR of Indians. Hyperglycaemia appeared similarly prevalent in Indians and West Indians, but less common in Europeans. Of the haemostatic factors, West Indians had a relatively low VIIc (not statistically significant), while Indians had an increased platelet count and reduced platelet volume. Improved understanding of these ethnic differences in CHD mortality may depend upon elucidation of the contrasts in HDL-cholesterol concentration.

Blood Coagulation Tests↗
PubMed1987

Residual effects of zopiclone (Imovane).

A double-blind, randomized, cross-over study has been conducted with zopiclone (Imovane), a new cyclopyrrolone hypnotic in ten healthy volunteers. Hypnotic efficacy has previously been demonstrated at a dose of 7.5 mg. The present study was designed to determine the overnight residual effects of different doses of the drug ranging from 2.5 to 10 mg. Measurement of complex reaction time was used as an objective test of impairment of psychomotor function. To supplement this, the volunteers were asked to report, by means of visual analogue scales, any perceived changes in their performance in the complex reaction time test, in their mood, and in the onset and quality of sleep. Complex reaction time testing revealed no significant impairment except at 12 h after the 10 mg dose. Subjective assessments of onset of sleep showed a dose-dependent shortening of sleep latency, confirming the hypnotic action of the drug. Volunteers were aware of a decline in psychomotor performance, of some sleepiness on awakening, and decreased alertness after previous night doses of 7.5 and 10 mg. It is concluded that a dose of 7.5 mg is optimal, producing significant hypnotic effect with minimal residual impairment.

Adult↗