Interfacial areas and gas hold-ups in bubble columns and packed bubble columns at elevated pressures

Interfacial areas and gas hold-ups have been determined at pressures up to 1.85 MPa in a bubble column with a diameter of 85.5 mm and for superficial gas velocities between 1 and 10 cm s−1. In some experiments the bubble column was packed with glass cylinders of length 5.0 mm and diameter 4.0 mm. The interfacial areas were determined by the chemical method using the model reaction between CO2 and aqueous diethanolamine (DEA) and hold-ups by observation of height differences.\ud \ud The interfacial areas in the packed bubble column are unaffected by pressure. The gas hold-ups as well as the interfacial areas in the bubble column increase with increasing operating pressure. The magnitude of the pressure influence depends on the superficial gas velocity. The positive influence of pressure on the gas hold-ups and the interfacial in the bubble column originates from the formation of smaller bubbles at the gas distributor

Associations of physical activity with body weight and fat in men and women

OBJECTIVE: Increasing physical activity is strongly advocated as a key public health strategy for weight gain prevention. We investigated associations of leisure-time physical activity (LTPA) and occupational/domestic physical activity with body mass index (BMI) and a skinfold-derived index of body fat (sum of six skinfolds), among normal-weight and overweight men and women.DESIGN: Analyses of cross-sectional self-report and measured anthropometric data.SUBJECTS: A total of 1302 men and women, aged 18-78 y, who were part of a randomly selected sample and who agreed to participate in a physical health assessment.MEASUREMENTS: Self-report measures of physical activity, measured height and weight, and a skinfold-derived index of body fatness.RESULTS: Higher levels of LTPA were positively associated with the likelihood of being in the normal BMI and lower body fat range for women, but few or no associations were found for men. No associations were found between measures of occupational/domestic activity and BMI or body fat for men or women.CONCLUSION: By using a skinfold sum as a more direct measure of adiposity, this study extends and confirms the previous research that has shown an association between BMI and LTPA. Our results suggest gender differences in the relationship of leisure-time physical activity with body fatness. These findings, in conjunction with a better understanding of the causes of such differences, will have important public health implications for the development and targeting of weight gain prevention strategies.<br /

Evidence of negative energy balance using doubly labelled water in elite Kenyan endurance runners prior to competition

Previous studies have found Kenyan endurance runners to be in negative energy balance during training and prior to competition. The aim of the present study was to assess energy balance in nine elite Kenyan endurance runners during heavy training. Energy intake and expenditure were determined over 7d using weighed dietary intake and doubly labelled water, respectively. Athletes were on average in negative energy balance (mean energy intake 13 241 (SD 1330) kJ/d v. mean energy expenditure 14 611 (SD 1043) kJ/d; P=0·046), although there was no loss in body mass (mean 56·0 (SD 3·4) kg v. 55·7 (SD 3·6) kg; P=0·285). The calculation of underreporting was 13; (range −24 to +9%) and almost entirely accounted for by undereating (9% (range −55 to +39%)) as opposed to a lack of significant underrecording (i.e. total water intake was no different from water loss (mean 4·2 (SD 0·6) l/d v. 4·5 (SD 0·8) l/d; P=0·496)). Fluid intake was modest and consisted mainly of water (0·9 (SD 0·5) l/d) and milky tea (0·9 (SD 0·3) l/d). The diet was high in carbohydrate (67·3 (SD 7·8) %) and sufficient in protein (15·3 (SD 4·0) %) and fat (17·4 (SD 3·9) %). These results confirm previous observations that Kenyan runners are in negative energy balance during periods of intense training. A negative energy balance would result in a reduction in body mass, which, when combined with a high carbohydrate diet, would have the potential in the short term to enhance endurance running performance by reducing the energy cost of runnin

National differences in implementation of minimally invasive surgery for colorectal cancer and the influence on short-term outcomes

Background: The timing and degree of implementation of minimally invasive surgery (MIS) for colorectal cancer vary among countries. Insights in national differences regarding implementation of new surgical techniques and the effect on postoperative outcomes are important for quality assurance, can show potential areas for country-specific improvement, and might be illustrative and supportive for similar implementation programs in other countries. Therefore, this study aimed to evaluate differences in patient selection, applied techniques, and results of minimal invasive surgery for colorectal cancer between the Netherlands and Sweden. Methods: Patients who underwent elective minimally invasive surgery for T1-3 colon or rectal cancer (2012–2018) registered in the Dutch ColoRectal Audit or Swedish ColoRectal Cancer Registry were included. Time trends in the application of MIS were determined. Outcomes were compared for time periods with a similar level of MIS implementation (Netherlands 2012–2013 versus Sweden 2017–2018). Multilevel analyses were performed to identify factors associated with adverse short-term outcomes. Results: A total of 46,095 Dutch and 8,819 Swedish patients undergoing MIS for colorectal cancer were included. In Sweden, MIS implementation was approximately 5 years later than in the Netherlands, with more robotic surgery and lower volumes per hospital. Although conversion rates were higher in Sweden, oncological and surgical outcomes were comparable. MIS in the Netherlands for the years 2012–2013 resulted in a higher reoperation rate for colon cancer and a higher readmission rate but lower non-surgical complication rates for rectal cancer if compared with MIS in Sweden during 2017–2018. Conclusion: This study showed that the implementation of MIS for colorectal cancer occurred later in Sweden than the Netherlands, with comparable outcomes despite lower volumes. Our study demonstrates that new surgical techniques can be implemented at a national level in a controlled and safe way, with thorough quality assurance.</p

National differences in implementation of minimally invasive surgery for colorectal cancer and the influence on short-term outcomes

Background: The timing and degree of implementation of minimally invasive surgery (MIS) for colorectal cancer vary among countries. Insights in national differences regarding implementation of new surgical techniques and the effect on postoperative outcomes are important for quality assurance, can show potential areas for country-specific improvement, and might be illustrative and supportive for similar implementation programs in other countries. Therefore, this study aimed to evaluate differences in patient selection, applied techniques, and results of minimal invasive surgery for colorectal cancer between the Netherlands and Sweden. Methods: Patients who underwent elective minimally invasive surgery for T1-3 colon or rectal cancer (2012–2018) registered in the Dutch ColoRectal Audit or Swedish ColoRectal Cancer Registry were included. Time trends in the application of MIS were determined. Outcomes were compared for time periods with a similar level of MIS implementation (Netherlands 2012–2013 versus Sweden 2017–2018). Multilevel analyses were performed to identify factors associated with adverse short-term outcomes. Results: A total of 46,095 Dutch and 8,819 Swedish patients undergoing MIS for colorectal cancer were included. In Sweden, MIS implementation was approximately 5 years later than in the Netherlands, with more robotic surgery and lower volumes per hospital. Although conversion rates were higher in Sweden, oncological and surgical outcomes were comparable. MIS in the Netherlands for the years 2012–2013 resulted in a higher reoperation rate for colon cancer and a higher readmission rate but lower non-surgical complication rates for rectal cancer if compared with MIS in Sweden during 2017–2018. Conclusion: This study showed that the implementation of MIS for colorectal cancer occurred later in Sweden than the Netherlands, with comparable outcomes despite lower volumes. Our study demonstrates that new surgical techniques can be implemented at a national level in a controlled and safe way, with thorough quality assurance.</p

PPARgamma activity in subcutaneous abdominal fat tissue and fat mass gain during short-term overfeeding

Objective: As the peroxisome proliferator-activated receptor (PPAR) plays a central role in fat mass regulation, we investigated whether initial subcutaneous PPAR activity is related to fat mass generation during overfeeding. Subjects: Fourteen healthy female subjects (age 254 years, BMI 22.12.3 kg/m2). Design and measurements: Subjects were overfed with a diet supplying 50% more energy than baseline energy requirements for 14 days. Fasting blood samples were analyzed for leptin, insulin and glucose. Fasting subcutaneous abdominal fat biopsies were obtained for analysis of PPAR1, PPAR2, aP2 and UCP2 mRNAs. Results: Initial PPAR1 and 2, aP2 and UCP2 mRNAs were not related to fat gain (P>0.12). However, PPAR1, PPAR2 and aP2 mRNA changes were positively related to changes in plasma leptin (