Objective To optimize and simplify the survey method of Oncomelania hupensis snail in marshland endemic re?gion of schistosomiasis and increase the precision,efficiency and economy of the snail survey. Methods A quadrate experimen?tal field was selected as the subject of 50 m×50 m size in Chayegang marshland near Henghu farm in the Poyang Lake region and a whole?covered method was adopted to survey the snails. The simple random sampling,systematic sampling and stratified ran?dom sampling methods were applied to calculate the minimum sample size,relative sampling error and absolute sampling error. Results The minimum sample sizes of the simple random sampling,systematic sampling and stratified random sampling meth?ods were 300,300 and 225,respectively. The relative sampling errors of three methods were all less than 15%. The absolute sampling errors were 0.221 7,0.302 4 and 0.047 8,respectively. Conclusion The spatial stratified sampling with altitude as the stratum variable is an efficient approach of lower cost and higher precision for the snail survey.

Objective: To investigate the prognostic value of chest computed tomography (CT) characteristics in crizotinib-treated pa-tients with advanced non-small cell lung cancer (NSCLC). Methods: Forty-seven patients with advanced ALK-rearranged NSCLC who re-ceived crizotinib treatment from January 2014 to March 2017 were enrolled in this retrospective study. Pre-treatment CT characteris-tics were evaluated. Patients were followed up after crizotinib treatment, and the best overall response and progression-free survival (PFS) were assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Results: The median PFS of all patients was 10 months. There was no association between CT characteristics and response. In univariate analysis, large tumor size (P=0.009), central type (P=0.002), consolidation of surrounding lung tissue (P=0.002), pleural effusion (P=0.001), and lymphangitic carcino-matosis (P=0.019) suggested a poor prognosis. Multivariate Cox regression analysis showed that location (hazard ratio, 3.219; 95% con-fidence interval: 1.517-6.833; P=0.002) was an independent prognostic predictor. Conclusions: Pre-treatment CT characteristics are useful in predicting the PFS of crizotinib-treated patients with advanced NSCLC harboring ALK rearrangement.

The article takes the experiment teaching combining Chaoxing Network Teaching Platform with BOPPPS model of obstetrics and gynecology in Chongqing Medical University as an example, and introduces the six teaching modules in detail that are followed in the mixed teaching mode: bridge in, objective, pre-assessment, participatory learning, post-assessment, and summary. Using the three-in-one assessment method of "process evaluation + incentive evaluation + summative evaluation", the learning effect of students was comprehensively evaluated. The practice proved that this mode can improve students' learning autonomy, exercise communication skills, cultivate teamwork spirit, promote the construction of clinical thinking, and improve teaching effect and classroom teaching quality.

BACKGROUND: Improving and maintaining the health of mothers and newborns is indisputably a global priority, especially during a pandemic. This study intends to examine the factors associated with cesarean section (CS) during lockdown time. METHODS: A total of 678 women who just gave birth within 7 days were enrolled from maternal and children hospitals in nine cities of China from April to May 2020. The delivery modes and potential influencing factors were investigated. The subgroup analysis and sensitivity analysis were used to examine the association of CS and risk factors among populations with different characteristics and to control for possible confounding, respectively. RESULTS: The overall rate of cesarean delivery was 37.3%. In multi-variant model, maternal age > 30 years (OR, 95% CI = 1.71, 1.21-2.41), higher pre-gestational BMI (OR, 95% CI = 1.16, 1.10-1.23), living in regions with confirmed COVID-19 cases > 500 (OR, 95% CI = 2.45, 1.74-3.45), and excess gestational weight gain (OR, 95% CI = 1.73, 1.17-2.55) were associated with cesarean delivery. These trends of associations were not changes in sensitivity analysis and subgroup analysis. Cesarean delivery occurred more in women who got more nutrition instruction during the pandemic period in the univariant model; however, this association showed insignificance in the multiple-variant analysis. CONCLUSION A high cesarean delivery rate was found in uninfected women who experienced lockdown in their third trimester. During the COVID-19 pandemic, more medical support should be provided in severely affected regions to ensure and promote health in pregnancy.