Objective To analyze the risk factors of preoperative lymph node staging (N-stage) deficiency in gastric cancer and establish a preoperative assessment model to assist in predicting preoperative N-stage. Methods A retrospective method was used to analyze the clinicopathological data of 268 patients with gastric cancer. The patients routinely underwent preoperative thin-section enhanced CT to assess preoperative N-stage. Results The risk factors for preoperative N-stage deficiency were analyzed in combination with postoperative pathological findings. Multifactorial logistic regression analysis was performed to determine influencing factors, and Kaplan-Meier analysis was used to plot the survival curves of preoperative N-stage accurate group and deficiency group. The nomogram plot and ROC curves of the prediction model were drawn using the R package. AUC, 95%CI, sensitivity, and specificity were calculated. Results Age, BMI, poor differentiation, and Lauren's classification as diffuse were independent risk factors for preoperative N-stage deficiency in gastric cancer (P < 0.05). Prognostic survival was significantly worse in the preoperative N stage-inadequate group than that in the accurate group (P=0.041). The AUC area was 0.935, with a sensitivity of 85.9% and specificity of 96.9%. Conclusion Young age, high BMI, poor differentiation, and Lauren's classification as diffuse are independent risk factors for preoperative N-stage deficiency. The established preoperative assessment model based on age, BMI, differentiation degree, and Lauren's classification in this study has relatively high credibility.

A novel paper-based analytical device(PAD)was prepared and applied to determine the xanthine oxi-dase(XOD)inhibitory activity of Salvia miltiorrhiza extracts(SME).First,polycaprolactone was 3D printed on filter paper and heated to form hydrophobic barriers.Then the modified paper was cut according to the specific design.Necessary reagents including XOD for the colorimetric assay were immobilized on two separate pieces of paper.By simply adding phosphate buffer,the reaction was performed on the double-layer PAD.Quantitative results were obtained by analyzing the color intensity with the specialized device system(consisting of a smartphone,a detection box and sandwich plates).The 3D-printed detection box was small,with a size of 9.0 cm x 7.0 cm x 11.5 cm.Color component G performed well in terms of linearity and detection limits and thus was identified as the index.The reaction con-ditions were optimized using a definitive screening design.Moreover,a 10％glycerol solution was found to be a suitable stabilizer.When the stabilizer was added,the activity of XOD could be maintained for at least 15 days under 4℃or-20℃storage conditions.The inhibitory activity of SME was investigated and compared to that of allopurinol.The results obtained with the PAD showed agreement with those ob-tained with the microplate method.In conclusion,the proposed PAD method is simple,accurate and has a potential for point-of-care testing.It also holds promise for use in rapid quality testing of medicinal herbs,intermediate products,and preparations of traditional Chinese medicines.

Objectives: This study explored the relationship between weight control and atrial fibrillation (AF) recurrence after catheter ablation in overweight and obese patients. Methods: We prospectively enrolled consecutive 333 overweight and obese patients aged 28 to 87 years old, who underwent catheter ablation for AF in Beijing Anzhen Hospital between October 2015 and February 2016. Data of patients′ characteristics, laboratory examination and treatment were collected at baseline. Each patient was followed up at 3, 6 and 12 months after ablation to collect information on weight, AF recurrence, stroke, major bleeding, hospitalization for cardiovascular reasons and death, etc. Patients were divided into weight controlled group (ΔBMI<-1 kg/m²) and weight uncontrolled group (ΔBMI≥-1 kg/m²), according to the changes in the most recent exposure BMI before AF recurrence in patients with recurrence or the BMI at 12 months′ follow-up in patients without recurrence and the BMI at baseline. Multivariate logistic regression was performed to adjust other known risk factors of AF recurrence and to explore the association between weight control and AF recurrence after catheter ablation. Results: There were 54 patients in weight controlled group and 279 patients in weight uncontrolled group. There were no significant differences in age, gender, education level, left atrial size and history of hypertension between the two groups (all P>0.05). The proportion of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was higher in the weight controlled group (50.0%(27/54) vs. 34.8%(97/279), P=0.034). However, there was no significant difference in the proportion of patients with obesity (33.3% (18/54) vs. 29.7% (83/279)), paroxysmal AF (59.3% (32/54) vs. 56.6% (158/279)) and AF duration less than 5 years (76.9% (40/52) vs. 65.4% (178/272)) between the weight controlled group and the uncontrolled group. During 1-year follow-up after ablation, the recurrence rate of AF was significantly lower in the weight controlled group than that in the weight uncontrolled group (14.8% (8/54) vs. 32.6%(91/279), P=0.009). Multivariable logistic regression analysis shows that weight control is independently associated with a lower postoperative AF recurrence rate (OR=0.40, 95%CI 0.18-0.90, P=0.026). Conclusion Weight control is strongly associated with a lower AF recurrence rate after catheter ablation in overweight and obese patients.