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Biomedical subjects

B Warburton

Publications and source records attributed to B Warburton.

At least 19 recordsLinked to original sources
PubMed2000

Effect of jaw shape in kill-traps on time to loss of palpebral reflexes in brushtail possums.

The effect of three configurations of the jaw of kill-traps on time to loss of palpebral reflex of brushtail possums (Trichosurus vulpecula) was assessed. Traps were Standard, with an offset rotating jaw closing past a pear-shaped constriction, Offset, with a rotating jaw closing past a straight edge, and Opposing, with a rotating jaw closing directly onto a static bar. Possums captured in the Standard and Offset traps had significantly lower times to loss of palpebral reflexes (42 and 50 sec respectively) than those captured in Opposing traps (122 sec). Both the Standard and Offset traps achieved total occlusion of both carotid arteries more frequently than the Opposing trap. Thus the killing effectiveness of kill traps designed for capturing possums can be improved by offsetting the jaws without the need to increase the power of the trap. Therefore, for some target species, such modifications might satisfy the demands of animal welfare proponents for traps that kill rapidly, without compromising trapper safety.

Animal Welfare↗
PubMed1997

Regional variations in deaths from volatile solvent abuse in Great Britain.

AIMS: To assess geographical variations in mortality and the relationship of socio-economic correlates to deaths from volatile substance abuse (VSA) in Great Britain. DESIGN: Analysis of the National Register of deaths from VSA by linking the addresses (postcode) of the deceased to census enumeration districts and hence wards and counties. SETTING AND PARTICIPANTS: All 775 deaths in Great Britain listed in the national register between 1985-91. Population counts from the 1991 census were used as denominators. MEASUREMENT: The Poisson heterogeneity test was used to test the null hypothesis that all standardized mortality ratios were from the same population. The t-test was used to compare differences in Townsend Deprivation scores between wards with and without VSA deaths. Multiple regression was used to assess the relationship between indices of deprivation and deaths from VSA. FINDINGS: One-third of all VSA deaths occurred in six regions of Great Britain which accounted for 17% of the at risk population. There was considerable variation in age standardized mortality ratios (ASMR) across regions. A ward level analysis indicated that wards with a VSA death had significantly higher levels of deprivation. The Townsend deprivation index showed mean deprivation scores of 2.8 and 0.2, respectively, for wards with and without a registered death (p < 0.0001). Multiple regression at county/region level found that 45% of the variation in ASMR was explained by the components of the Townsend deprivation index. CONCLUSIONS: Factors associated with deprivation are important in VSA deaths and this should be taken into account in planning public health measures to prevent mortality.

Adolescent↗
PubMed1996

Electronic mail.

Explore the source record for details and available documents.

Communication↗
PubMed1985

Surface rheological properties of hyaluronic acid solutions.

Using an oscillating ring surface rheometer, surface shear rheological studies of hyaluronic acid solutions at physiological pH have demonstrated the elastico-viscous nature of the surface films. The properties of these surface films change with time and are shown to be related to bulk concentration, ionic strength and pH. This ageing behaviour can be explained on the basis of molecular conformational changes and molecular segmental kinetics. The results are discussed in relation to the postulated function of hyaluronic acid in synovial fluid.

Elasticity↗
PubMed1984

Particle size analysis of microcapsules.

To standardize the preparation of three-walled w/o/w microcapsules it was necessary to assess their particle size distribution, since they occur as both unicored and multicored types. The log-normal law, reported to be obeyed by many particulate systems, including microcapsules, was not applicable to the size data. A curve-fitting computer program using least squares minimization was used to assess the size distribution data. The models tested were the unimodal and bimodal log-normal distributions, the bimodal form being the most appropriate. Using the equations to the curves of best fit, the modal size and standard deviation of each population were estimated, and the relative percentages of unicored and multicored microcapsules could be deduced from an analysis of the bimodal curves in which they were represented as the sum of two constituent unimodal distributions.

Acacia↗
PubMed1984

Surface rheological observations on human plasma.

The weak interactions between plasma proteins are of possible importance both in haemorheology and in the pathology of several diseases. The use of surface rheology is a convenient way to study the forces arising between surface adsorbed protein molecules. A surface rheological measuring head has been designed for the Contraves LS-30 viscometer. Plasma samples of healthy human subjects showed a rapidly developing viscous surface layer with a mean peak value of 2.10(-3) Ns/m surface viscosity at 30- 60 seconds. After that the viscosity of the surface layer gradually decreased to zero between 8-20 minutes. The rate of the observed decrease was not related to shearing. There was no difference between samples anticoagulated with heparin or EDTA. The time course of the described phenomenon coincides with that of thrombocyte and white cell adherence to solid surfaces exposed to plasma.

Blood Viscosity↗
PubMed1982

Three-ply walled w/o/w microcapsules formed by a multiple emulsion technique.

A new method of microencapsulation is described. Interfacial rheological studies had shown the formation of a rigid bipolymer film at the interface between an aqueous solution of a water-soluble polymer and a non-aqueous solution of an oil-soluble polymer. This led to the idea that small spherical bodies might be formed on making a w/o/w emulsion from these solutions. The present work has shown that ethyl cellulose/acacia microcapsules are formed when the organic solvent ethyl acetate is removed from the multiple emulsion drops. These microcapsules may be obtained as a free-flowing powder.

Capsules↗