Three-dimensional dynamics of a single bubble rising near a vertical wall:Paths and wakes

In order to clarify the migration mechanism and wake behavior of a single bubble rising near a vertical wall,three-dimensional direct numerical simulations are implemented based on the open-source soft-ware Basilisk and various types of migration paths like linear,zigzag and spiral are investigated.The volume of fluid(VOF)method is used to capture the bubble interface at a small scale,while the gas-liquid interface and high-velocity-gradient regions in the flow field are encrypted with the adaptive mesh refinement technology.The results show that the vertical wall has an obstructive effect on the diffusion of the vortex boundary layer on the surface of the bubble migrating in a straight line,and the resulting reaction force tends to push the bubbles away from the wall surface.For the zigzag or spiral movement of a bubble in the x-y plane,the perpendicular wall is an unstable factor,but on the contrary,the motion in the z-y plane is stabilized.

Machine learning-assisted ensemble analysis for the prediction of urinary tract infection in elderly patients with ovarian cancer after cytoreductive surgery

BACKGROUND Urinary tract infection(UTI)is a common type of postoperative infection following cytoreductive surgery for ovarian cancer,which severely impacts the prognosis and quality of life of patients.AIM To develop a machine learning assistant model for the prevention and control of nosocomial infection.METHODS A total of 674 elderly patients with ovarian cancer who were treated at the Department of Gynaecology at Jingzhou Central Hospital between January 31,2016 and January 31,2022 and met the inclusion criteria of the study were selected as the research subjects.A retrospective analysis of the postoperative UTI and related factors was performed by reviewing the medical records.Five machine learning-assisted models were developed using two-step estimation methods from the candidate predictive variables.The robustness and clinical applicability of each model were assessed using the receiver operating characteristic curve,decision curve analysis and clinical impact curve.RESULTS A total of 12 candidate variables were eventually included in the UTI prediction model.Models constructed using the random forest classifier,support vector machine,extreme gradient boosting,and artificial neural network and decision tree had areas under the receiver operating characteristic curve ranging from 0.776 to 0.925.The random forest classifier model,which incorporated factors such as age,body mass index,catheter,catheter intubation times,blood loss,diabetes and hypoproteinaemia,had the highest predictive accuracy.CONCLUSION These findings demonstrate that the machine learning-based prediction model developed using the random forest classifier can be used to identify elderly patients with ovarian cancer who may have postoperative UTI.This can help with treatment decisions and enhance clinical outcomes.