On the lubrication of mechanical face seals

Hence, in this thesis, a model is presented which is able to calculate a complete Stribeck curve for a mechanical face seal and, as a consequence, the transition from full film to mixed lubrication as a function of the operational conditions. This model is based on a combination of a contact model and a film thickness equation. The model, which is isothermal, incorporates waviness, coning, face geometry, roughness, pressure of the fluid to be sealed and load

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

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

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