In a circular channel passing over-limiting current (faster than diffusion), transient vortices of bulk electroconvection are observed in salt-depleted region within the horizontal plane. The spatiotemporal evolution of the salt concentration is directly visualized, revealing the propagation of a deionization shock wave driven by bulk electroconvection up to millimeter scales. This novel mechanism leads to quantitatively similar dynamics as for deionization shocks in charged porous media, which are driven instead by surface conduction and electro-osmotic flow at micron to nanometer scales. The remarkable generality of deionization shocks under over-limiting current could be used to manipulate ion transport in complex geometries for desalination and water treatment.

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Background. Bladder cancer is a common malignant tumor of the urinary system in the clinic. It has multiple lesions, easy recurrence, easy metastasis, poor prognosis, and high mortality. Objective. The aim of this study is to investigate the impact of laparoscopic radical cystectomy (LRC) and open radical cystectomy (ORC) on the surgical outcome, complications, and prognosis of elderly patients with bladder cancer. Materials and Methods. One hundred elderly bladder cancer patients who underwent surgery in our hospital from June 2019 to June 2021 were selected for the retrospective study and were divided into 50 cases each in the ORC group and the LRC group according to the different surgical methods. The ORC group was treated with ORC, and the LRC group implemented LRC treatment. The differences in surgery, immune function, recent clinical outcomes, and complications between the two groups were observed and compared. Results. The mean operative time, mean intraoperative bleeding, intraoperative and postoperative transfusion rate, and transfusion volume of patients in the LRC group were statistically significant when compared to the ORC group. The differences in the meantime to resume eating, time to get out of bed, mean number of days in hospital after surgery, and the amount of postoperative numbing analgesics used by patients in the LRC group after surgery were statistically significant compared to the ORC group ( P < 0.05 ). There was no statistically significant difference in the comparison of immune function between the two groups before surgery ( P > 0.05 ), while the comparison of CD8+ and B cells 1 week after surgery of the LRC group was significantly better than that of the ORC group ( P < 0.05 ), and the operation time of the LRC group was longer than that of the ORC group ( P < 0.05 ). Statistical analysis of postoperative complications showed that the overall incidence of postoperative complications in the LRC group was significantly lower than that in the ORC group (16.67% vs. 46.67%) ( P < 0.05 ). Conclusion. LRC has less surgical trauma and intraoperative bleeding, faster postoperative recovery, and fewer postoperative complications, providing some reference for clinical surgery for elderly bladder cancer patients.