Existing neuroregulatory techniques can achieve precise stimulation of the whole brain or cortex, but high-focus deep brain stimulation has been a technical bottleneck in this field. In this paper, based on the theory of negative permeability emerged in recent years, a simulation model of magnetic replicator is established to study the distribution of the induced electric field in the deep brain and explore the possibility of deep focusing, which is compared with the traditional magnetic stimulation method. Simulation results show that a single magnetic replicator realized remote magnetic source. Under the condition of the same position and compared with the traditional method of stimulating, the former generated smaller induced electric field which sharply reduced with distance. By superposition of the magnetic field replicator, the induced electric field intensity could be increased and the focus could be improved, reducing the number of peripheral wires while guaranteeing good focus. The magnetic replicator model established in this paper provides a new idea for precise deep brain stimulation, which can be combined with neuroregulatory techniques in the future to lay a foundation for clinical application.
ObjectiveTo explore the risk factors affecting on catheter obstruction during hyperthermic intraperitoneal chemotherapy (HIPEC). MethodsBased on the inclusion and exclusion criteria, the data of the patients who underwent HIPEC and related perfusion records at the First Affiliated Hospital of Xi’an Jiaotong University from February 2023 to December 2023 were retrospectively collected. The collected data were analyzed using Chi-square tests, machine learning, and non-parametric tests. The significance level was set at α=0.05. ResultsA total of 210 HIPEC patients meeting the criteria were included, of whom 51 (24.3%) experienced catheter obstruction. The univariate analysis revealed that the inflow-outflow temperature gradient of the perfusate (ΔT of the perfusate), perfusion flow rate, chemotherapy exposure, hypertension status, surgical approach, and HIPEC catheter length were associated with catheter obstruction (P<0.05). Subsequently, combining the results of the univariate analysis with feature values screened by machine learning, the following factors were selected, including HIPEC catheter length, ΔT of the perfusate, perfusion flow rate, age, gender, chemotherapy exposure, fibrinogen level, hypertension status, surgical approach, and blood transfusion. A predictive model for HIPEC catheter obstruction based on these features was established, achieving an area under the receiver operating characteristic curve (AUC) (95%CI) of 0.825 (0.757, 0.893). ConclusionThis study preliminarily identifies key factors influencing the incidence of catheter obstruction during HIPEC treatment, such as ΔT of the perfusate, perfusion flow rate, chemotherapy exposure, surgical approach, HIPEC catheter length, and hypertension, continuously monitoring these factors, thereby reducing the risk of catheter obstruction.