The development and validation of clinical prediction models based on artificial intelligence (AI) and machine learning methods have become increasingly widespread. However, the prediction model bias risk and applicability evaluation tool developed in 2019 (i.e., PROBAST-2019) has shown significant limitations. Therefore, an expanded and updated version of the PROBAST-2019 tool was released in 2025, known as the PROBAST+AI tool. The tool is divided into two parts including model development and model evaluation. It aims to comprehensively and systematically evaluate potential methodological quality issues in model development, bias risks in model evaluation, and the applicability of models, regardless of the modeling method used. This paper provides a systematic interpretation of the PROBAST+AI tool's items and case analyses, with the aim of guiding and assisting researchers engaged in related studies and promoting the high-quality development of clinical predictive model research.

Objective:Analyzing the relationship between negative life events and depressive symptoms in university freshmen,and the mediating effects of neuroticism and the moderating role of exercise frequency.Meth-ods:A sampling of 8 079 university freshmen,and the Patient Health Questionnaire was used to assess depressive symptoms,the Eysenck Personality Inventory-Neuroticism subscale to assess neuroticism,the self-administered questionnaire to assess the number of negative life events that the participants had experienced and the exercise fre-quency.Model 4 in the Process plug-in was used to test the mediating effect of neuroticism,and Model 7 to test the moderating role of exercise frequency.Results:The numbers of negative life events were positively correlated with the depressive symptoms scores(r=0.16,P＜0.01),and were positively correlated with the neuroticism scores(r=0.26,P＜0.01).The neuroticism scores were positively correlated with the depressive symptoms scores(r=0.52,P＜0.01).Neuroticism score partially mediated between negative life events and depressive symptoms score,with a mediating effect of 78.4％,and exercise frequency score moderated between negative life events and neuroti-cism scores(β=-0.05,P=0.032).Conclusion:Negative life events are associated with depressive symptoms,neuroticism plays a mediating role,and exercise frequency could moderate negative life events and neuroticism.

Objective To compare the effects of two head holders on the setup errors during head and neck neoplasms radiotherapy.Methods Totally 30 patients were divided into groups A and B randomly and equally.Group A applied TypeSTM Extension for setup,and group B used Type-S Overlay Board,with thermoplastic film applied to fixation.Varian23IX image guided linear accelerator was involved in the therapy,and the patients underwent CBCT-guided therapy once a week in 6 weeks.The setup errors at left-right,head-foot and anterior-posterior directions were obtained by bone registration and manual checking.Results The absolute setup error at anterior-posterior direction of group A,was (2.31 ± 1.35) mm,which was significantly higher than (1.88±1.79) mm of group B (P=0.032).There were no obvious differences between the setup errors of group A and those of group B (P＞0.05),and the weekly absolute errors of group A were not statistically different from those of group B (P＞0.05).Conclusion There are no significant differences between the effects of the two head holders on the setup errors during head and neck neoplasms radiotherapy,and proper head holder can be selected according to clinical requirements.