Building Booster Separation Aerodynamic Databases for Artemis II

NASAs Artemis II mission will mark the return of humans to near-lunar space for the first time since Apollo. Shortly after launch on the Space Launch System (SLS), a critical phase of ascent occurs when 16 small rockets fire to push the boosters away from the core. Minimizing the risk of failure during separation requires the construction of multiple 13-dimensional databases, including perturbations in position, flight conditions, and engine thrust. The SLS Computational Fluid Dynamics team used NASAs FUN3D flow solver on the Pleiades and Electra supercomputers to run 5,780 simulations at nominal conditions and over 8,000 simulations with a core stage engine failure to generate the databases needed to verify the booster separation system for Artemis II

Annular pancreas: endoscopic and pancreatographic findings from a tertiary referral ERCP center

Background and Aims Annular pancreas is a congenital anomaly whereby pancreatic tissue encircles the duodenum. Current knowledge of endoscopic findings of annular pancreas is limited to small case series. The aim of this study was to describe the endoscopic and pancreatographic findings of patients with annular pancreas at a large tertiary care ERCP center. Methods This is a retrospective observational study. Our Institutional Review Board–approved, prospectively collected ERCP database was queried for cases of annular pancreas. The electronic medical records were searched for patient and procedure-related data. Results From January 1, 1994, to December 31, 2016, 46 patients with annular pancreas underwent ERCP at our institution. Index ERCP was technically successful in 42 patients (91.3%), and technical success was achieved in all 46 patients (100%) after 2 attempts, when required. A duodenal narrowing or ring was found in most patients (n = 39, 84.8%), yet only 2 (4.3%) had retained gastric contents. Pancreas divisum was found in 21 patients (45.7%), 18 of which were complete divisum. Pancreatobiliary neoplasia was the indication for ERCP in 7 patients (15.2%). Pancreatographic findings consistent with chronic pancreatitis were noted in 15 patients (32.6%) at the index ERCP. Conclusion This is the largest series describing the endoscopic and pancreatographic findings of patients with annular pancreas. We found that 45.7% of patients had concurrent pancreas divisum. Endoscopic therapy was successful in most patients at our institution after 1 ERCP, and in all patients after a second ERCP. Nearly one-third of patients had findings consistent with chronic pancreatitis at the time of index ERCP. It is unclear whether this may be a feature of the natural history of annular pancreas

Real world costs and cost-effectiveness of Rituximab for diffuse large B-cell lymphoma patients: a population-based analysis.

BackgroundCurrent treatment of diffuse-large-B-cell lymphoma (DLBCL) includes rituximab, an expensive drug, combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy. Economic models have predicted rituximab plus CHOP (RCHOP) to be a cost-effective alternative to CHOP alone as first-line treatment of DLBCL, but it remains unclear what its real-world costs and cost-effectiveness are in routine clinical practice.MethodsWe performed a population-based retrospective cohort study from 1997 to 2007, using linked administrative databases in Ontario, Canada, to evaluate the costs and cost-effectiveness of RCHOP compared to CHOP alone. A historical control cohort (n = 1,099) with DLBCL who received CHOP before rituximab approval was hard-matched on age and treatment intensity and then propensity-score matched on sex, comorbidity, and histology to 1,099 RCHOP patients. All costs and outcomes were adjusted for censoring using the inverse probability weighting method. The main outcome measure was incremental cost per life-year gained (LYG).ResultsRituximab was associated with a life expectancy increase of 3.2 months over 5 years at an additional cost of $16,298, corresponding to an incremental cost-effectiveness ratio of$61,984 (95% CI $34,087-$135,890) per LYG. The probability of being cost-effective was 90% if the willingness-to-pay threshold was $100,000/LYG. The cost-effectiveness ratio was most favourable for patients less than 60 years old ($31,800/LYG) but increased to $80,600/LYG for patients 60-79 years old and$110,100/LYG for patients ≥ 80 years old. We found that post-market survival benefits of rituximab are similar to or lower than those reported in clinical trials, while the costs, incremental costs and cost-effectiveness ratios are higher than in published economic models and differ by age.ConclusionsOur results showed that the addition of rituximab to standard CHOP chemotherapy was associated with improvement in survival but at a higher cost, and was potentially cost-effective by standard thresholds for patients <60 years old. However, cost-effectiveness decreased significantly with age, suggesting that rituximab may be not as economically attractive in the very elderly on average. This has important clinical implications regarding age-related use and funding decisions on this drug

Clinical response to dorsal duct drainage via the minor papilla in refractory obstructing chronic calcific pancreatitis

Background and study aims Complete stone removal from the main pancreatic duct might not be achieved in all patients with obstructive chronic calcific pancreatitis. We report our results for endoscopic dorsal pancreatic duct (DPD) bypass of obstructing stones in the ventral pancreatic duct (VPD). Patients and methods 16 patients with obstructive chronic calcific pancreatitis were treated with a DPD bypass. Clinical success was defined as significant pain relief and no hospital admissions for pain management during the ongoing treatment period. Results Among 16 patients meeting entry criteria, 10 (62.5%) had a history of unsuccessful endoscopic therapy, and 8 had failed extracorporeal shockwave lithotripsy (ESWL). Clinical success was achieved in 12 patients (75 %). Among these responders, 10 patients (83.3 %) had markedly improved or complete pain relief after the first stent placement, which persisted throughout the follow-up period; 11 patients (91.7 %) were able to discontinue their daily analgesics. Conclusions In selected patients with obstructive chronic calcific pancreatitis, the DPD bypass may be considered as a rescue endoscopic therapy, potentially obviating the need for surgery when standard endoscopic methods and ESWL fail

Low Serum Pancreatic Amylase and Lipase Values Are Simple and Useful Predictors to Diagnose Chronic Pancreatitis

Background/Aims This study aimed to evaluate the diagnostic role of low serum amylase and lipase values in the detection of chronic pancreatitis. Methods Patients underwent endoscopic retrograde cholangiopancreatography and were diagnosed with non-calcific chronic pancreatitis (NCCP; n=99) and calcific chronic pancreatitis (CCP; n=112). Patient serum amylase and lipase values were compared with those of healthy controls (H; n=170). Results The median serum amylase (normal range, 19 to 86 U/L) and lipase values (7 to 59 U/L) (P25–P75) were 47.0 (39.8 to 55.3) and 25.0 (18.0 to 35.0) for H, 34.0 (24.5 to 49.0) and 19.0 (9.0 to 30.0) for NCCP, and 30.0 (20.0 to 40.8) and 10.0 (3.0 to 19.0) for CCP, respectively. The cutoff values with the highest diagnostic accuracy for discriminating NCCP from H were 40 U/L for amylase and 20 U/L for lipase, respectively, and for CCP from H were 38 U/L for amylase and 15 U/L for lipase, respectively. For the diagnosis of NCCP with a criterion of serum amylase <40 and lipase <20 U/L, the sensitivity, specificity, positive predictive value, and negative predictive values were 37.4%, 88.8%, 66.1%, and 70.9%, respectively. Conclusions Serum amylase and/or lipase levels below the normal serum range are highly specific for chronic pancreatitis patients. Clinicians should not ignore low serum pancreatic enzyme values

Additional flap on plastic stents for improved antimigration effect in the treatment of post-cholecystectomy bile leak

Background and study aims: In plastic stent insertion for treatment of post-cholecystectomy bile leak, stent migration may be more common due to the absence of a shelf to anchor the stent. We evaluated how adding a flap to straight plastic stents for this indication might influence the rate of stent migration when compared to use of conventional plastic stents. Patients and methods: This is a retrospective study including patients referred for ERCP for treatment of post-cholecystectomy bile leak. Patients with a customized anti-migration flap stent had the additional flap created on the distal end of straight plastic stents, intended to aid in anchoring in the distal supra-sphincteric biliary duct. The primary endpoint is stent migration events. The secondary endpoint is bile leak resolution after first ERCP session. Results: Thirty-two patients were treated with the experimental additional flap stents and 225 patients were treated with standard straight biliary stents. The total failure rate of bile leak resolution after a single endoscopic treatment for all treated was 10.5 % (27/257) and the total stent migration rate for all enrolled was 15.2 % (39/257). Stent migration rate was lower in the additional flap stent group than in the conventional group (3.1 % vs. 16.9 %, respectively, P  = 0.04). Furthermore, significantly more patients had resolution of their bile leak after the first ERCP session in the group with the additional flap (100 % vs. 88 %, respectively, P  = 0.03). Conclusion: A plastic biliary stent with an extra flap may have improved performance with regard to stent migration and resolution of bile leak over standard plastic biliary stents

Aerodynamic Databases for the Space Launch System

No abstract availabl

Building Aerodynamic Databases for the SLS Design Process

NASA's new Space Launch System (SLS) will be the first rocket since the Saturn V (1967-1973) to carry astronauts beyond low earth orbit-and will carry 10% more payload than Saturn V and three times the payload of the space shuttle. The SLS configuration consists of a center core and two solid rocket boosters that separate from the core as their fuel is exhausted two minutes after lift-off. During these first two minutes of flight, the vehicle powers its way through strong shock waves as it accelerates past the speed of sound, then pushes beyond strong aerodynamic loads at the maximum dynamic pressure, and is ultimately enveloped by gaseous plumes from the booster-separation motors. The SLS program relies on computational fluid dynamic (CFD) simulations to provide much of the data needed to build aerodynamic databases describing the structural load distribution, surface pressures, and aerodynamic forces on the vehicle

Effect of calcineurin inhibitor on post-endoscopic retrograde cholangiopancreatography pancreatitis in patients with liver transplantation: a propensity-matched cohort study

Background/Aims A calcineurin inhibitor may alter pancreatic function and inflammatory reaction. This study aimed to determine the possible pharmacologic effect of the calcineurin inhibitor, tacrolimus, on pancreatic function, and to determine its preventive effect on post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis in liver transplantation (LT) patients. Methods The serum amylase and lipase values before and after LT were compared. The frequency of post-ERCP pancreatitis was compared between non-LT and LT patients, using propensity score matching method. Results Median serum amylase values (normal range, 19 to 86 U/L) were 49.0 U/L (38.0 to 68.0) before LT and 27.0 U/L (19.3 to 36.8) after LT, and median serum lipase values (normal range, 7 to 59 U/L) were 40.0 U/L (26.5 to 54.0) before LT and 10.5 U/L (6.0 to 21.0) after LT. Both serum amylase and lipase values significantly decreased after LT (p < 0.001), and to a level comparable to chronic pancreatitis. There was a marginal significant difference between the non-LT and LT groups before the propensity score matching with respect to frequency of post-ERCP pancreatitis (16 [3.2%] in non-LT group vs. 2 [0.9%] in LT group, p = 0.069). After propensity score matching, a marginal significant difference still existed with respect to frequency of post-ERCP pancreatitis (7 [4.8%] in non-LT group vs. 1 [0.7%] in LT group, p = 0.067). Conclusions The immunosuppression with calcineurin inhibitor may reduce not only the pancreatic enzyme dynamics but also inciting inflammatory event including post-ERCP pancreatitis