This study examined the effects of the incorporation of carbon fiber (CF) and silicon carbide powder (SCP) into a high temperature vulcanized (HTV) silicone rubber, poly(dimethylsiloxane) (PDMS) containing vinyl groups on the ablation properties using an oxy-acetylene torch test. The ablation test results showed that CF enhanced the hardness of the char formed on the composite surface during the oxy-acetylene torch test and was an important factor determining the ablation properties. SCP was also beneficial in enhancing the surface char hardness of the HTV/CF composite. A new method was devised to evaluate the ablation properties more objectively by measuring the time elapsed for a rectangular-shaped silicone rubber composite with specimens loaded with a constant weight to burn and fail off during the oxy-acetylene torch test. The mechanical properties of the silicone rubber composites were also examined as a function of the additive content using a universal test machine (UTM). V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 831-838, 2011

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Background: Laparoscopic Pancreaticoduodenectomy (LPD) is one of the most challenging procedures. The aim of this study is to analyze the learning curve of LPD based on a single surgeon's experience. Methods: The medical records of 111 consecutive patients who underwent LPD by a single surgeon between March 2014 and October 2022 were analyzed retrospectively. The learning curve was evaluated using the cumulative summation (CUSUM) and risk-adjusted CUSUM (RA-CUSUM) methods. Surgical failure was defined as open conversion, and severe complication (Clavian-Dindo grade ≥ 3). Early and late phases were classified along the result of the learning curve analysis, and the operative outcomes of each phase were compared. Results: In a CUSUM analysis for operation time, the operation time decreased after the first 33 cases. As a result of the RA-CUSUM analysis, the LPD technique was stabilized after the 44th case. The operation time, length of stay, rate of delayed gastric emptying, severe complication, and surgical failure in the late phase were significantly lower than in the early phase. Conclusions: For stabilization of the LPD technique and operative outcomes, 44 cases are required.