1,721,092 research outputs found
Electrostatic ignition assessment of flammable clouds in large vessels by finite-element potential and electric field analysis
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The influence of flow regime on electrostatic destabilisation of water-in-oil emulsions.
No full textElectrostatic destabilization of water-in-oil emulsions under conditions of turbulent flow
No full textValidation of the diagnosis of venous thromboembolism in general practice database studies
No full textAims: The study was conducted to determine whether the method for selecting cases of venous thromboembolism (VTE) from general practice databases significantly affected the findings of an epidemiological study. Methods: Cases of VTE were identified from the UK General Practice Research Database (GPRD) by searching for codes for deep vein thrombosis (DVT) and pulmonary embolism (PE). These had to be supported by evidence of anticoagulation and be exposed to a combined oral contraceptive (COC) at the time of the event. Additional information about the event was sought from general practitioners who were requested to complete a questionnaire and to supply anonymised copies of hospital letters and discharge summaries. Results: Of the 285 cases identified from the GPRD, additional information was available for 177 VTE events. This information showed that 84% of those events were supported by hospital investigations or a death certificate. Using only verified cases, rather than all GPRD identified events, did not alter the results of the epidemiological study. Conclusions: The GPRD provides information of sufficiently high quality to allow valid epidemiological research of VTE events. Excluding cases without a database record of hospital admission would lead to valid events being overlooked, and an under-estimate of the disease incidenc
Venous thromboembolic disease and combined oral contraceptives: A re-analysis of the Mediplus database
No full textIn October 1995 the Committee on Safety of Medicines advised UK doctors and pharmacists that oral contraceptives containing desogestrel and gestodene were associated with double the risk of venous thromboembolic events (VTE) compared to pills containing other progestogens. In 1997 data was analysed from the MediPlus database of UK general practitioner records, which reported odds ratios for desogestrel and gestodene lower than that for levonorgestrel. Here the results of a more stringent nested case control analysis on the MediPlus database are reported. The study was larger and cases were verified. A crude incidence of idiopathic VTE was found amongst users of combined oral contraceptives of 4.6 per 10 000 exposed women years. Using levonorgestrel 150 ?g + ethinyloestradiol 30 ?g as reference, non-significant odds ratios of 1.1 (0.5–2.6) for desogestrel 150 ?g + ethinyloestradiol 30 ?g and 1.1 (0.5–2.4) for gestodene 75 ?g + ethinyloestradiol 30 ?g were found. The results of this study show no significant difference in risk between different formulations of combined oral contraceptive. <br/
Patterns of contraception in UK women with Type 1 diabetes mellitus: A GP database study
No full textAim: To establish the patterns of contraceptive prescribing for women aged 15–49 with Type 1 diabetes mellitus (DM) and compare them with the patterns in women without diabetes.Methods: This was a cross-sectional study using a UK primary care database.Results: Nine hundred and thirty-eight women with a diagnosis of Type 1 DM were identified. A comparison group of women aged 15–49 without diabetes (n = 10 000) were randomly selected from the database. Twenty-five per cent of the women with diabetes and 32% without diabetes were prescribed a hormonal contraceptive in 1994. Women with Type 1 DM were more likely to be prescribed a combined oral contraceptive than a progestogen only pill (POP) but were 2.12 (95% CI 1.65–2.72) times more likely to be prescribed a POP than women without diabetes and were less likely to be prescribed a combined pill – odds ratio 0.53 (95% CI 0.44–0.64). The pregnancy rate in women with Type 1 DM over the age of 25 years was lower than for women without diabetes. Women under 25 years with Type 1 DM seemed more likely to record a pregnancy.Conclusions: Differences between women with Type 1 DM and those without diabetes highlight the variation in the way that GPs and patients evaluate the risks and benefits when deciding on contraception.<br/
The ESPLIM System: Assessment of a novel, compact and efficient solvent extraction system utilising electric field driven dispersion processes
No full textAssessment of industrial electrostatic hazards using finite-element electric field analysis
No full textCharged clouds, generated in industrial processes, can lead to large values of space potential and electric field inside a vessel. Isolated masses of airborne liquid within can carry induced charge to the wall resulting in electrostatic discharges. Critical values of space potential can be found using a relationship between the jet safety factor and the material hazard coefficient. A computer package is described which allows complex space potential profiles and electric fields to be modelled for a prescribed space charge density. This allows the central space potential, a key indicator of electrostatic risk, to be evaluated. Examples are presented of two recent hazard investigations made by Wolfson Electrostatics
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