This article reports on the fabrication of microcellular polycarbonate (PC) foams with unimodal or bimodal cell-size distributions using supercritical CO2 (scCO2) as a physical blowing agent. The saturation and desorption behaviors of CO2 in PC for various pressures are investigated. The effects of key processing parameters such as saturation pressure, foaming temperature, and foaming time on the relative density, cell sizes, and the cell densities of the unimodal foams are discussed in detail. The glass transition temperature (Tg) of the polymer/gas mixture is found to present a good linear relationship with the absorbed CO2 concentration, and foaming of the samples takes place above the Tg of the polymer/gas mixture. A two-step batch depressurization process is applied to produce bimodal PC foams with both small and large cells, which exhibit significantly improved tensile properties compared to the unimodal foams. In addition, the phenomenon of extensional stress-induced nucleation promoting the generation of nanocellular structures around the expanding larger cells is observed at the increased foaming temperature of 160℃ in the production of bimodal foams.

BackgroundThe prognostic nutritional index (PNI) is calculated based on the serum albumin concentration and the total lymphocyte count. The aim of this study was to investigate the prognostic ability of the PNI for postoperative complications after liver resection to treat hepatocellular carcinoma (HCC) within the Milan criteria.ResultsPostoperative complications were observed in 166 (44.6%) patients. The optimal cutoff value of the PNI was set at 45.6 for postoperative complications. Patients in the PNI-low (PNI < 45.6) group were more likely to have postoperative complications, more blood loss, a longer surgery time and a longer hospital stay than patients in the PNI-high group (PNI > 45.6). Our regression analysis demonstrated that the preoperative PNI and albumin-bilirubin (ALBI) score were significantly associated with postoperative complications (Pearson correlation coefficient, -0.865, p < 0.001). The multivariate analysis revealed that the PNI was an independent predictor of postoperative complications.Materials and MethodsThree-hundred and seventy-two patients who underwent partial hepatectomy for HCC from 2003 to 2014 were identified. The cutoff value of the PNI was determined by a receiver operating characteristic (ROC) curve analysis. Univariate and multivariate analyses were performed to identify clinicopathological features associated with postoperative complications.ConclusionThe PNI may be a significant prognostic factor for evaluating short-term outcomes of patients with HCC after partial hepatectomy.

MCA is a safe, effective, and time-saving modality for biliojejunostomy.

A preliminary exploration of the mechanism for the occurrence of two types of various magnetic structures in the magnetotail Chinese Science Bulletin 46, 981 (2001); Application of magnetic compression anastomosis technique in pediatric surgery Chinese Science Bulletin 65, 1264 (2020); Application research and prospect of magnetic surgery techniques in trauma

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