The Influence of Plastic Bulk Deformation on Surface Roughness and Frictional Behavior during Deep Drawing Processes

In Sheet Metal Forming (SMF) processes, friction does play an important role. This with respect to the increase of product quality demands and the ability of predicting these processes by for instance finite element simulations. The existing simulation models do not contain an adequate friction model. In SMF processes different contact situations can be distinguished. As a result different coefficients of friction are locally present, which influences the forming process.\ud \ud Experiments are performed on a testing device by which it is possible to simulate the operational conditions as present in SMF processes. This test rig is a combination of a tensile tester and a friction measuring device, by which it is possible to measure the coefficient of friction as a function of the operational conditions (velocity and contact pressure) and deformation (elastic or plastic) in a well controlled way. Friction is presented in a generalized Stribeck-curve in which the different lubrication regimes can be distinguished, i.e. Boundary Lubrication (BL) and Mixed Lubrication (ML), which are also occurring during SMF processes.\ud \ud In SMF processes the sheet material deforms elastically and plastically and therefore the surface roughness will change and as a consequence will influence the frictional behavior between sheet and tool. In this paper, the influence of plastic deformation on A) the surface microgeometry and B) as a consequence of that on the frictional behavior of the sheet-tool system is studied. With the aid of a 3D-surface interference microscope, the microgeometry of the deformed material has been analyzed. The result of this investigation is that the CLA-roughness due to the deformation first decreases and then increases with increasing deformation. Furthermore, friction is hardly influenced due to the change in surface roughness. No change in the shape and the level of the generalized Stribeck curve is found

Nationwide practice and outcomes of endoscopic biliary drainage in resectable pancreatic head and periampullary cancer

BACKGROUND: Guidelines advise self-expanding metal stents (SEMS) over plastic stents in preoperative endoscopic biliary drainage (EBD) for malignant extrahepatic biliary obstruction. This study aims to assess nationwide practice and outcomes. METHODS: Patients with pancreatic head and periampullary cancer who underwent EBD before pancreatoduodenectomy were included from the Dutch Pancreatic Cancer Audit (2017-2018). Multivariable logistic and linear regression models were performed. RESULTS: In total, 575/1056 patients (62.0%) underwent preoperative EBD: 246 SEMS (42.8%) and 329 plastic stents (57.2%). EBD-related complications were comparable between the groups (44/246 (17.9%) vs. 64/329 (19.5%), p = 0.607), including pancreatitis (22/246 (8.9%) vs. 25/329 (7.6%), p = 0.387). EBD-related cholangitis was reduced after SEMS placement (10/246 (4.1%) vs. 32/329 (9.7%), p = 0.043), which was confirmed in multivariable analysis (OR 0.36 95%CI 0.15-0.87, p = 0.023). Major postoperative complications did not differ (58/246 (23.6%) vs. 90/329 (27.4%), p = 0.316), whereas postoperative pancreatic fistula (24/246 (9.8%) vs. 61/329 (18.5%), p = 0.004; OR 0.50 95%CI 0.27-0.94, p = 0.031) and hospital stay (14.0 days vs. 17.4 days, p = 0.005; B 2.86 95%CI -5.16 to -0.57, p = 0.014) were less after SEMS placement. CONCLUSION: This study found that preoperative EBD frequently involved plastic stents. SEMS seemed associated with lower risks of cholangitis and less postoperative pancreatic fistula, but without an increased pancreatitis risk

Lower Risk of Recurrence with a Higher Induction Dose of Mesalazine and Longer Duration of Treatment in Ulcerative Colitis: Results from the Dutch, Non-Interventional, IMPACT Study

Background & Aims: The dose and duration of mesalazine treatment for ulcerative colitis (UC) is a potentially important determinant of effectiveness, with evidence suggesting that continuing the induction dose for 6-12 months may improve outcomes; however, real-world data are lacking. We assessed mesalazine use in Dutch clinical practice, including how differences in dose and duration affected UC outcomes.Methods: Adults with mild-to-moderate UC who received oral prolonged-release mesalazine de novo or had a dose escalation for an active episode were followed for 12 months in this non-interventional study (ClinicalTrials.gov identifier: NCT02261636). The primary endpoint was time from start of treatment to dose reduction (TDR). Secondary endpoints included recurrence rate, adherence, and work productivity.Results: In total, 151 patients were enrolled, of whom 108 (71.5%) were newly diagnosed with UC. The majority (120; 79.5%) received a dose of >= 4 g/day. Nearly one-third (48; 31.8%) underwent dose reduction, with mean TDR being 8.3 months. Disease extent and endoscopic appearance did not influence duration of induction therapy, while TDR increased with higher baseline UCDAI scores. TDR was longer in patients without (mean 8.8 months) than with (4.1 months) recurrence, although not significantly (p=0.09). Patients on >= 4 g/day had a significantly lower chance of recurrence versus those on 2-6 months vs 3-6 months: 0.19 (95%CI: 0.08-0.46); p= 4 g/day [0.15 (0.06-0.40) vs 0.26 (0.01-11.9) for 2-= 4 g/day) and longer duration of treatment (>6 months) was associated with a lower recurrence risk.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Impact of nationwide enhanced implementation of best practices in pancreatic cancer care (PACAP-1):a multicenter stepped-wedge cluster randomized controlled trial

Background: Pancreatic cancer has a very poor prognosis. Best practices for the use of chemotherapy, enzyme replacement therapy, and biliary drainage have been identified but their implementation in daily clinical practice is often suboptimal. We hypothesized that a nationwide program to enhance implementation of these best practices in pancreatic cancer care would improve survival and quality of life. Methods/design: PACAP-1 is a nationwide multicenter stepped-wedge cluster randomized controlled superiority trial. In a per-center stepwise and randomized manner, best practices in pancreatic cancer care regarding the use of (neo)adjuvant and palliative chemotherapy, pancreatic enzyme replacement therapy, and metal biliary stents are implemented in all 17 Dutch pancreatic centers and their regional referral networks during a 6-week initiation period. Per pancreatic center, one multidisciplinary team functions as reference for the other centers in the network. Key best practices were identified from the literature, 3 years of data from existing nationwide registries within the Dutch Pancreatic Cancer Project (PACAP), and national expert meetings. The best practices follow the Dutch guideline on pancreatic cancer and the current state of the literature, and can be executed within daily clinical practice. The implementation process includes monitoring, return visits, and provider feedback in combination with education and reminders. Patient outcomes and compliance are monitored within the PACAP registries. Primary outcome is 1-year overall survival (for all disease stages). Secondary outcomes include quality of life, 3- and 5-year overall survival, and guideline compliance. An improvement of 10% in 1-year overall survival is considered clinically relevant. A 25-month study duration was chosen, which provides 80% statistical power for a mortality reduction of 10.0% in the 17 pancreatic cancer centers, with a required sample size of 2142 patients, corresponding to a 6.6% mortality reduction and 4769 patients nationwide. Discussion: The PACAP-1 trial is designed to evaluate whether a nationwide program for enhanced implementation of best practices in pancreatic cancer care can improve 1-year overall survival and quality of life. Trial registration: ClinicalTrials.gov, NCT03513705. Trial opened for accrual on 22th May 2018

Impact of nationwide enhanced implementation of best practices in pancreatic cancer care (PACAP-1): A multicenter stepped-wedge cluster randomized controlled trial

Background: Pancreatic cancer has a very poor prognosis. Best practices for the use of chemotherapy, enzyme replacement therapy, and biliary drainage have been identified but their implementation in daily clinical practice is often suboptimal. We hypothesized that a nationwide program to enhance implementation of these best practices in pancreatic cancer care would improve survival and quality of life. Methods/design: PACAP-1 is a nationwide multicenter stepped-wedge cluster randomized controlled superiority trial. In a per-center stepwise and randomized manner, best practices in pancreatic cancer care regarding the use of (neo)adjuvant and palliative chemotherapy, pancreatic enzyme replacement therapy, and metal biliary stents are implemented in all 17 Dutch pancreatic centers and their regional referral networks during a 6-week initiation period. Per pancreatic center, one multidisciplinary team functions as reference for the other centers in the network. Key best practices were identified from the literature, 3 years of data from existing nationwide registries within the Dutch Pancreatic Cancer Project (PACAP), and national expert meetings. The best practices follow the Dutch guideline on pancreatic cancer and the current state of the literature, and can be executed within daily clinical practice. The implementation process includes monitoring, return visits, and provider feedback in combination with education and reminders. Patient outcomes and compliance are monitored within the PACAP registries. Primary outcome is 1-year overall survival (for all disease stages). Secondary outcomes include quality of life, 3- and 5-year overall survival, and guideline compliance. An improvement of 10% in 1-year overall survival is considered clinically relevant. A 25-month study duration was chosen, which provides 80% statistical power for a mortality reduction of 10.0% in the 17 pancreatic cancer centers, with a required sample size of 2142 patients, corresponding to a 6.6% mortality reduction and 4769 patients nationwide. Discussion: The PACAP-1 trial is designed to evaluate whether a nationwide program for enhanced implementation of best practices in pancreatic cancer care can improve 1-year overall survival and quality of life. Trial registration: ClinicalTrials.gov, NCT03513705. Trial opened for accrual on 22th May 2018

Nationwide practice and outcomes of endoscopic biliary drainage in resectable pancreatic head and periampullary cancer

Background: Guidelines advise self-expanding metal stents (SEMS) over plastic stents in preoperative endoscopic biliary drainage (EBD) for malignant extrahepatic biliary obstruction. This study aims to assess nationwide practice and outcomes.Methods: Patients with pancreatic head and periampullary cancer who underwent EBD before pancreatoduodenectomy were included from the Dutch Pancreatic Cancer Audit (2017 & ndash;2018). Multi variable logistic and linear regression models were performed.Results: In total, 575/1056 patients (62.0%) underwent preoperative EBD: 246 SEMS (42.8%) and 329 plastic stents (57.2%). EBD-related complications were comparable between the groups (44/246 (17.9%) vs. 64/329 (19.5%), p = 0.607), including pancreatitis (22/246 (8.9%) vs. 25/329 (7.6%), p = 0.387). EBD-related cholangitis was reduced after SEMS placement (10/246 (4.1%) vs. 32/329 (9.7%), p = 0.043), which was confirmed in multivariable analysis (OR 0.36 95%CI 0.15 & ndash;0.87, p = 0.023). Major postoperative complications did not differ (58/246 (23.6%) vs. 90/329 (27.4%), p = 0.316), whereas postoperative pancreatic fistula (24/246 (9.8%) vs. 61/329 (18.5%), p = 0.004; OR 0.50 95%CI 0.27 & ndash;0.94, p = 0.031) and hospital stay (14.0 days vs. 17.4 days, p = 0.005; B 2.86 95%CI & minus;5.16 to & minus;0.57, p = 0.014) were less after SEMS placement.Conclusion: This study found that preoperative EBD frequently involved plastic stents. SEMS seemed associated with lower risks of cholangitis and less postoperative pancreatic fistula, but without an increased pancreatitis risk.Surgical oncolog

Nationwide practice and outcomes of endoscopic biliary drainage in resectable pancreatic head and periampullary cancer

Background: Guidelines advise self-expanding metal stents (SEMS) over plastic stents in preoperative endoscopic biliary drainage (EBD) for malignant extrahepatic biliary obstruction. This study aims to assess nationwide practice and outcomes. Methods: Patients with pancreatic head and periampullary cancer who underwent EBD before pancreatoduodenectomy were included from the Dutch Pancreatic Cancer Audit (2017–2018). Multivariable logistic and linear regression models were performed. Results: In total, 575/1056 patients (62.0%) underwent preoperative EBD: 246 SEMS (42.8%) and 329 plastic stents (57.2%). EBD-related complications were comparable between the groups (44/246 (17.9%) vs. 64/329 (19.5%), p = 0.607), including pancreatitis (22/246 (8.9%) vs. 25/329 (7.6%), p = 0.387). EBD-related cholangitis was reduced after SEMS placement (10/246 (4.1%) vs. 32/329 (9.7%), p = 0.043), which was confirmed in multivariable analysis (OR 0.36 95%CI 0.15–0.87, p = 0.023). Major postoperative complications did not differ (58/246 (23.6%) vs. 90/329 (27.4%), p = 0.316), whereas postoperative pancreatic fistula (24/246 (9.8%) vs. 61/329 (18.5%), p = 0.004; OR 0.50 95%CI 0.27–0.94, p = 0.031) and hospital stay (14.0 days vs. 17.4 days, p = 0.005; B 2.86 95%CI −5.16 to −0.57, p = 0.014) were less after SEMS placement. Conclusion: This study found that preoperative EBD frequently involved plastic stents. SEMS seemed associated with lower risks of cholangitis and less postoperative pancreatic fistula, but without an increased pancreatitis risk

Upgrade of the BW-IP material tester for research on tribological properties of mechanical seals

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