A Novel Radiological Predictor for Postoperative Pancreatic Fistula After Stapled Distal Pancreatectomy

Background Distal pancreatectomy (DP) is the main surgical treatment of benign and malignant lesions located in pancreatic body and tail. Postoperative pancreatic fistula (POPF) following DP is still a considerable cause of morbidity. Identification of risk factors for POPF after DP might provide some preventive applications. We aimed to evaluate the factors affecting POPF after DP and to present a new and easy radiological predictive factor. Materials and Methods Thirty-four patients underwent DP with stapler closure were included. Several risk factors for clinically relevant POPF (CR-POPF) were analyzed. Additionally, computed tomography findings of pancreatic thickness (PT), main pancreatic duct diameter (MPDD), and PT/MPDD ratio were evaluated for POPF. Results CR-POPF was observed in 10 patients (29.4%). Univariate and multivariate analyses showed that previous abdominal surgery and PT/MPDD ratio were predictive factors for CR-POPF after DP ( P = 0.040, P = 0.034, respectively). The cutoff value for the PT/MPDD ratio was 8. Conclusion A PT/MPDD ratio greater than 8 (a wide pancreas with a narrow duct) is a significant predictive factor for CR-POPF following DP.

Research on Coating Uniformity of Unidirectional Interleaving Painting

Unidirectional interleaving painting is presented for robot to spray long and narrow duct. It adopts a same overlapping distance and only two seed paths in the same direction which are used in turn.To optimize robot trajectory for spray painting, uniformity model of unidirectional interleaving painting based on parabolic deposition model and thickness variance is built, and coating uniformity is studied. Non-dimensional calculation results show that overlapping distance and interleaving distance are the main influencing factors of coating uniformity. The value of thickness deviation is not greater than 0.000 9 in four areas, two of which should be chosen to plan painting path for better coating uniformity. The comparison experiment confirms that interleaving painting can improve coating uniformity.

Dispersion properties of ducted whistlers, generated by lightning discharge

Whistler-mode wave propagation in magnetospheric ducts of enhanced cold plasma density is studied. The case of the arbitrary ratio of the duct radius to the whistler wavelength is considered, where the ray-tracing method is not applicable. The set of duct eigenmodes and their spatial structure are analysed and dependencies of eigenmode propagation properties on the duct characteristics are studied. Special attention is paid to the analysis of the group delay time of one-hop propagation of the whistler wave packet along the duct. We found that, in contrast to the case of a wide duct, the group delay time in a rather narrow duct decreases as the eigenmode number increases. The results obtained are suggested for an explanation of some types of multi-component whistler signals.