[Learning curve analysis of 73 cases of central pancreatectomy].

Objective: To explore the learning curve of central pancreatectomy (CP) and provide an excellent reference for surgeons to get the point of this operation. Methods: Clinical data of 73 patients who underwent CP in the same operation team from January 2006 to January 2018 were collected and retrospectively analyzed by the moving average method (MAM) and the cumulative sum method (CUSUM). Data was analyzed by statistical package for social science (SPSS) software. Results: According to the MAM and CUSUM curves, the learning process of CP could be divided into two stages. At the first stage (n=1-11), the median operation time was 340 minutes and the median intraoperative hemorrhage was 400 ml. In the second stage (n=12-73), the median operation time was 213 minutes and the median intraoperative hemorrhage was 100 ml. The difference was statistically significant (P<0.001). There were no significant differences between the two stages of patients in terms of other aspects (P>0.05). Conclusions: CP can be mastered after 11 cases of exercises. In the first 11 operations, surgeons should get familiar with the operation process, respond actively to emergencies and accumulate experience to gain this surgical technique fast.

[Surgical treatment and prognosis of pancreatic neuroendocrine carcinoma].

Objective: Pancreatic neuroendocrine carcinoma (pNEC) is a highly malignant tumor.This study aimed to evaluate the role of surgery and the prognosis for patients with pancreatic neuroendocrine carcinoma (pNEC). Methods: We collected and reviewed all clinical data of patients who underwent radical surgery for pNEC from Jan 2000 through Jan 2016 in our hospital. Cox-regression analysis wasused to evaluate the factors potentially influencing survival. Results: Twenty patients including 11 males and 9 females (median age, 62.5 years) were included in this study. All patients underwent radical surgery and 17 cases received postoperative platinum-based chemotherapy.The median follow-up time was 41 months (range, 1 to 127 months). The 1-, 3-, and 5-year survival rates of the patients were 66.7%, 51.5% and 28.1%, with a median survival time of 75.3 months.The multivariate analysis indicated that tumor size and Ki-67 index were of prognostic significance. Conclusions: Pancreatic neuroendocrine carcinomas are rare but increasing in incidence. Patients with localized nonmetastatic primary tumors seem to benefit from surgery. Early diagnosis and multimodality therapy are key points of an improved survival.

Stoichiometric ratio of dissolved organic carbon to nitrate regulates nitrous oxide emission from the biochar-amended soils.

Biochar has the potential to mitigate nitrous oxide (N2O) emissions from soils. However, the mechanisms responsible for N2O emission in biochar-amended soils are yet to be elucidated. In this study, an incubation experiment was carried out to investigate the effects of seven biochars (eucalyptus, softwood mixture, mallee, jarrah, peanut shell, green waste and radiata pine) on the stoichiometric shifts of dissolved organic carbon (DOC), nitrate (NO3--N) and N2O emission in two contrasting soils (Ferrosol with 5.3% total C, 0.46% total N; Tenosol with 0.4% total C, 0.01% total N). All biochar treatments were found to significantly reduce N2O emission in Tenosol by 61-72%. However, in Ferrosol, biochars' impacts on N2O emission were variable, with only peanut shell, green waste and radiata pine bicohars significantly reducing N2O emission by 17-23%. A decrease in NO3- availability in most biochar-amended treatments also was observed in both soils compared with the control. The N2O fluxes in Ferrosol were mainly regulated by the shifts in the availability and stoichiometry of DOC and NO3- induced by the biochar amendments. The DOC derived from biochars increased DOC:NO3- ratio in Ferrosol at the beginning of the experiment, but these effects disappeared 7days after incubation. Overall, the N2O fluxes were C-limited due to the presence of high concentrations of NO3- in Ferrosol. However, in Tenosol, the relationship between stoichiometry of DOC:NO3- and N2O fluxes was much weaker than Ferrosol and N2O fluxes mainly limited by the concentration of NO3-. This study demonstrated that the mechanisms responsible for biochar effects on soil N2O fluxes are considered to be soil and biochar specific.