Using morphometry and impregnation technique of lanthanum nitrate,acomparative investigation on the epidermis structure of high and low electricresistance skin points was carried out in mice and rabbits at both light and electronmicroscope level,with special emphasis on the structure of gap junctions in epidermis.It was observed that the frequency of gap junctions in low resistance points wassignificantly higher,and their diameter was larger than that in high resistancepoints,while no difference was found in other structure parameters examinedbetween the two types of skin points.It is assumed that the gap junctions may bethe structure basis for the difference in skin electric resistance.

Objective To evaluate the value of postoperative radiotherapy (PORT) in patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy. Methods Patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy were chosen from the SEER Research Plus Database [17 Registries, November 2012 Submission (2000-2019)]. The patients were divided into a PORT group and a non-PORT group according to whether the PORT was used. To balance baseline characteristics between non-PORT and PORT groups, R software was used to conduct a propensity score matching (PSM) with a ratio of 1 : 1 and a matching tolerance of 0.01. Both the Cox regression analysis and Kaplan-Meier survival analysis were conducted to evaluate the value of PORT in terms of overall survival (OS) and disease-specific survival (DSS). Results In total, 2468 patients with stage ⅢA-N2 non-small cell lung cancer were enrolled, including 1078 males and 1390 females with a median age of 65 (58-71) years. There were 1336 patients in the PORT group, and 1132 patients in the non-PORT group. Cox regression analysis showed that PORT was not significantly associated with OS (multivariate analysis: HR=1.051, 95%CI 0.949-1.164, P=0.338) and DSS (multivariate analysis: HR=1.094, 95%CI 0.976-1.225, P=0.123). No statistical difference was found in the OS or DSS between non-PORT group and PORT group after PSM analysis (P＞0.05). Conclusion PORT does not have a survival benefit for patients with stage ⅢA-N2 non-small cell lung cancer who received complete resection and chemotherapy.