Risk factors and outcomes for patients with pancreatic cancer undergoing surgical exploration without resection due to metastatic disease:A national cohort study

Background:Unresectable disease is sometimes diagnosed during surgery in patients with pancreatic ductal adenocarcinoma(PDAC).This study aimed to identify preoperative risk factors for metastatic disease diagnosed at surgical exploration and to investigate and compare survival in resected and nonresected patients.Methods:Patients were identified from the Swedish National Pancreatic and Periampullary Cancer Registry 2010-2018.Predictors of metastatic disease were evaluated with a multivariable logistic regression model,and survival was evaluated with Kaplan-Meier estimates and log-rank tests.Results:In total,1938 patients with PDAC were scheduled for surgery.An unresectable situation was diagnosed intraoperatively in 399 patients(20.6%),including 234(12.1%)with metastasized disease.Independent risk factors for metastasis were involuntary weight loss(OR=1.72;95%CI:1.27-2.33)and elevated carbohydrate antigen 19-9(CA19-9)(35-599 U/m L,OR=1.79,95%CI:1.11-2.89;≥600 U/m L,OR=3.24,95%CI:2.04-5.17).Overall survival was lower among patients with metastasized disease than that among patients with a resectable tumor(P<0.001).Conclusions:Involuntary weight loss and an elevation of CA19-9 are preoperative risk factors for diagnosing metastasized disease during surgical exploration.

Design and Benchmark Tests of a Multi-Channel Hydrophone Array System for Dolphin Echolocation Recordings

This paper describes in depth the design and application considerations of a computer based measurement system enabling 1 MS/s simultaneous sampling of 47 hydrophones for cross sectional recordings of echolocation beams of toothed whales (Odontocetes). An earlier prototype version of the system has previously only been presented as a brief proof of principle that did not offer a complete description of the software and hardware solution. Crucial hardware and software design considerations of the further developed system include the re-arm times of the burst mode sampling and the dual-core distributed execution of the software components. The rearm time was measured to 283 μs, using a 550 μs long sample window around each click. This enables burst mode sampling of clicks with an inter-click interval as short as 833 μs. It is shown through both synthetic benchmark tests of the system and through field measurements of bottlenose dolphins (Tursiops truncatus) and a beluga whale (Delphinapterus leucas) that it is capable of acquiring, analyzing and visualizing data in run-time. It operates effectively also in highly reverberant surroundings like concrete pools and shallow waters. Burst mode sampling allows the system to block reflections with 0.3 - 0.5 m longer propagation paths than the direct path. It is suggested that the system’s compliance to reverberant recording sites makes it valuable in future dolphin echolocation studies.