Ultrasound has become the optimal imaging method for prenatal screening,whereas the operator dependence and high imaging variability may affect the accuracy of results and examination efficiency.Applied in segmentation and recognition tasks in images,deep learning(DL)is able to derive higher-level features from lower-level features,accurately characterize the inherent laws or information features of raw data.The research progresses of DL applicated in prenatal ultrasonic section analysis were reviewed in this article.

BackgroundThe development of executive function in adolescents is influenced by many environmental factors. Previous studies have found that perceived stress is closely related to executive function， whereas its role in the mediation of executive function remains poorly studied. ObjectiveTo explore the role of negative affect and self-hate in mediating the relationship between perceived stress and executive function in adolescents， so as to assist the improvement of executive function in adolescents. MethodsQuestionnaires were administered to 7 734 adolescents from five junior and five senior high schools in Rizhao city， Shandong province from 1 to 30 May 2022. Data were collected using a self-made questionnaire， and adolescents were assessed using Perceived Stress Scale （PSS）， Behavior Rating Inventory of Executive Function-Self Report Version （BRIEF-SR）， Patient Health Questionnaire （PHQ-4） and Self-Hate Scale （SHS）. Spearman correlation analysis was conducted to examine the correlation between variables. A Bootstrap method was chosen to examine the mediation effect of self-hate and negative affect on the relationship between perceived stress and executive function in adolescents. ResultsA total of 7 012 （90.66%） valid questionnaires were retrieved. BRIEF-SR score was positively correlated with PSS， PHQ-4 and SHS scores （r=0.564， 0.653， 0.597， P<0.01）. PSS score was positively correlated with PHQ-4 and SHS scores （r=0.615， 0.531， P<0.01）. PHQ-4 score was positively correlated with SHS score （r=0.566， P<0.01）. The value of mediation effect of perceived stress on executive function was 0.574 （95% CI： 0.555~0.594）. Self-hate （indirect effect value of 0.160， 95% CI： 0.145~0.175） and negative affect （indirect effect value of 0.143， 95% CI： 0.129~0.158）， separately from each other， mediated the relationship between perceived stress and executive function， and a chained mediation effect of self-hate and negative affect was also documented （indirect effect value of 0.065， 95% CI： 0.058~0.073）， accounting for 27.87%， 24.91% and 11.32% of the total effect， respectively. ConclusionThe perceived stress of adolescents may be a influencing factor of the executive function. Additionally， perceived stress can either directly affect executive function or indirectly through the separate or chained mediation via negative affect and self-hate.