45 research outputs found

    Prediction of attrition in agitated particle beds

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    The majority of pharmaceutical powders produced through crystallisation are dried in agitated dryers. The rotation of the impeller causes shear deformation of the bed, which enhances the drying rate, but also leads to particle breakage. A method of predicting the extent of breakage occurring due to agitation is described and applied for Paracetamol in a small-scale dryer. The distributions of stresses and strains in the bed are estimated using the Distinct Element Method (DEM). The information obtained here is then coupled with the measured attrition of Paracetamol in an annular shear cell in order to predict the attrition in the agitated bed. The experiments are carried out on dry material so as to establish purely the effect of stresses and strains on attrition, whilst keeping moisture content and temperature constant.The shear cell provides uniform condition for stresses and strains so that the breakage taking place under relatively well-defined conditions is quantified. In contrast, the prevailing shear stresses and strains in the agitated bed have wide distributions, as little shearing takes place near the impeller shaft, whilst there are considerable shearing stresses near the impeller tip. Therefore, the bed is divided into a number of segments for which the extent of attrition can be evaluated for each segment, based on the shear cell data. A good quantitative agreement is found between the predictions and experimental results obtained for the attrition of Paracetamol in the small scale dryer. The resulting prediction also suggests that, for a given number of impeller rotations, the extent of breakage is independent of impeller speed in the range tested (20-78. rpm). This is expected as the prevailing strain rates are too low for the inertial effects to be dominating and the shear stresses are independent of shear rates within the range investigated. The attrition prediction suggest that over half of the attrition occurs in the bottom third of the bed, with increased attrition at greater radial distances. The attrition is also predicted to occur predominantly within the region extending from 30° in front of to 30° behind the impeller

    Low incidence of SARS-CoV-2, risk factors of mortality and the course of illness in the French national cohort of dialysis patients

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    Camp-based family treatment of childhood obesity: randomised controlled trial

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    Objective To compare the effectiveness of a 2-year camp-based family treatment programme and an outpatient programme on obesity in two generations. Design Pragmatic randomised controlled trial. Setting Rehabilitation clinic, tertiary care hospital and primary care. Patients Families with at least one child (7–12 years) and one parent with obesity. Interventions Summer camp for 2 weeks and 4 repetition weekends or lifestyle school including 4 days family education . Behavioural techniques motivating participants to healthier lifestyle. Main outcome measures Children: 2-year changes in body mass index (BMI) SD score (SDS). Parents: 2-year change in BMI. Main analyses: linear mixed models. Results Ninety children (50% girls) were included. Baseline mean (SD) age was 9.7 (1.2) years, BMI 28.7 (3.9) kg/m 2 and BMI SDS 3.46 (0.75). The summer-camp children had a lower adjusted estimated mean (95% CI) increase in BMI (−0.8 (−3.5 to −0.2) kg/m 2 ), but the BMI SDS reductions did not differ significantly (−0.11 (−0.49 to 0.05)). The 2-year baseline adjusted BMI and BMI SDS did not differ significantly between summer-camp and lifestyle-school completers, BMI 29.8 (29.1 to 30.6) vs 30.7 (29.8 to 31.6) kg/m 2 and BMI SDS 2.96 (2.85 to 3.08) vs 3.11 (2.97 to 3.24), respectively. The summer-camp parents had a small reduction in BMI (−0.9 (−1.8 to −0.03) vs −0.8 (−2.1 to 0.4) in the lifestyle-school group), but the within-group changes did not differ significantly (0.3 (−1.7 to 2.2)). Conclusions A 2-year family camp-based obesity treatment programme had no significant effect on BMI SDS in children with severe obesity compared with an outpatient family-based treatment programme. Trial registration number NCT01110096

    Camp-based family treatment of childhood obesity: randomised controlled trial

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    Objective To compare the effectiveness of a 2-year camp-based family treatment programme and an outpatient programme on obesity in two generations. Design Pragmatic randomised controlled trial. Setting Rehabilitation clinic, tertiary care hospital and primary care. Patients Families with at least one child (7–12 years) and one parent with obesity. Interventions Summer camp for 2 weeks and 4 repetition weekends or lifestyle school including 4 days family education. Behavioural techniques motivating participants to healthier lifestyle. Main outcome measures Children: 2-year changes in body mass index (BMI) SD score (SDS). Parents: 2-year change in BMI. Main analyses: linear mixed models. Results Ninety children (50% girls) were included. Baseline mean (SD) age was 9.7 (1.2) years, BMI 28.7 (3.9) kg/m2 and BMI SDS 3.46 (0.75). The summer-camp children had a lower adjusted estimated mean (95% CI) increase in BMI (−0.8 (−3.5 to −0.2) kg/m2), but the BMI SDS reductions did not differ significantly (−0.11 (−0.49 to 0.05)). The 2-year baseline adjusted BMI and BMI SDS did not differ significantly between summer- camp and lifestyle-school completers, BMI 29.8 (29.1 to 30.6) vs 30.7 (29.8 to 31.6) kg/m2 and BMI SDS 2.96 (2.85 to 3.08) vs 3.11 (2.97 to 3.24), respectively. The summer-camp parents had a small reduction in BMI (−0.9 (−1.8 to −0.03) vs −0.8 (−2.1 to 0.4) in the lifestyle-school group), but the within-group changes did not differ significantly (0.3 (−1.7 to 2.2)). Conclusions A 2-year family camp-based obesity treatment programme had no significant effect on BMI SDS in children with severe obesity compared with an outpatient family-based treatment programme

    Camp-based family treatment of childhood obesity: randomised controlled trial

    No full text
    Objective To compare the effectiveness of a 2-year camp-based family treatment programme and an outpatient programme on obesity in two generations. Design Pragmatic randomised controlled trial. Setting Rehabilitation clinic, tertiary care hospital and primary care. Patients Families with at least one child (7–12 years) and one parent with obesity. Interventions Summer camp for 2 weeks and 4 repetition weekends or lifestyle school including 4 days family education. Behavioural techniques motivating participants to healthier lifestyle. Main outcome measures Children: 2-year changes in body mass index (BMI) SD score (SDS). Parents: 2-year change in BMI. Main analyses: linear mixed models. Results Ninety children (50% girls) were included. Baseline mean (SD) age was 9.7 (1.2) years, BMI 28.7 (3.9) kg/m2 and BMI SDS 3.46 (0.75). The summer-camp children had a lower adjusted estimated mean (95% CI) increase in BMI (−0.8 (−3.5 to −0.2) kg/m2), but the BMI SDS reductions did not differ significantly (−0.11 (−0.49 to 0.05)). The 2-year baseline adjusted BMI and BMI SDS did not differ significantly between summer-camp and lifestyle-school completers, BMI 29.8 (29.1 to 30.6) vs 30.7 (29.8 to 31.6) kg/m2 and BMI SDS 2.96 (2.85 to 3.08) vs 3.11 (2.97 to 3.24), respectively. The summer-camp parents had a small reduction in BMI (−0.9 (−1.8 to −0.03) vs −0.8 (−2.1 to 0.4) in the lifestyle-school group), but the within-group changes did not differ significantly (0.3 (−1.7 to 2.2)). Conclusions A 2-year family camp-based obesity treatment programme had no significant effect on BMI SDS in children with severe obesity compared with an outpatient family-based treatment programme
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