Surgical effect and gastrointestinal functional recovery of laparoscopic-guided total mesorectal excision in patients with rectal cancer.

INTRODUCTION: To explore the surgical effect and gastrointestinal functional recovery of laparoscopic-guided total mesorectal excision (LGTME) in patients with rectal cancer. PATIENTS AND METHODS: A total of 150 rectal cancer patients who underwent surgical treatment in our hospital from July 2022 to July 2023 were selected and randomly divided into two groups using a random number table. There were 75 cases in the control group (CG) who underwent traditional open rectal total mesorectal excision surgery and 75 cases in the experimental group (EG) who underwent LGTME. The surgical effects of the two groups were compared, and the gastrointestinal and anal functional recovery of the two groups were compared before and after treatment. RESULTS: Intraoperative bleeding, incision length, time to initial feeding and time to anal exhaust in the EG were significantly lower than those in the CG (P < 0.05). Before treatment, there was no significant difference in gastrointestinal function and anal function between the two groups (P > 0.05). After treatment, the levels of motilin, gastrin, neuropeptide Y and basic fibroblast growth factor in the EG were significantly higher than those in the CG, with statistical significance (P < 0.05); the maximum anal systolic pressure and resting anal sphincter pressure in the EG were significantly lower than those in the CG (P < 0.05); the rectal sensitivity threshold volume (RSTV) and rectal maximum volume threshold in the EG were significantly higher than those in the CG (P < 0.05). There was no significant difference in most postoperative complications between the two groups (P > 0.05). CONCLUSION: LGTME improves the surgical effects of rectal cancer patients, promotes the recovery of gastrointestinal function and has a small effect on anal function indicators, thereby reducing hospital stay.

Experimental study of the effect of water level and wind speed on radon exhalation of uranium tailings from heap leaching uranium mines.

Water level and wind speed have important influences on radon release in particle-packing emanation media. Based on radon migration theory in porous media under three water level conditions, an experimental setup was designed to measure the surface radon exhalation rate of uranium tailings from heap leaching uranium mine at different water levels and wind speeds. When the water level was at 0.3 m (overlying depth 0.05 m), radon transfer velocities at the gas-liquid interface were also measured at different wind speeds. Results show that when the water level was equal to or lower than the surface of the sample, the radon exhalation rate increased with increasing wind speed and decreased with increasing water level. When the water level was higher than the surface of the sample, radon exhalation rate of the water surface increased with increasing surface wind speed. The wind speed, however, was less influential on the radon exhalation rate as the depth of the overlying water increased, with a dramatic decrease in radon release. That said, at different wind speeds, radon transfer velocities at the gas-liquid interface were consistent with literature. On the other hand, changes in wind speed had significant influences on the radon transfer velocity at the gas-liquid interface, with the effect less pronounced at higher wind speeds.

A universal laboratory method for determining physical parameters of radon migration in dry granulated porous media.

The particle size and heaped methods of exhalation media have important effects on physical parameters, such as the free radon production rate, porosity, permeability, and radon diffusion coefficient. However, existing methods for determining those parameters are too complex, and time-consuming. In this study, a novel, systematic determining method was proposed based on nuclide decay, radon diffusion migration theory, and the mass conservation law, and an associated experimental device was designed and manufactured. The parameters of uranium ore heap and sandy soil of radon diffusion coefficient (D), free radon production rate (α), media permeability (k), and porosity (ε) were obtained. At the same time, the practicality of the novel determining method was improved over other methods, with the results showing that accuracy was within the acceptable range of experimental error. This novel method will be of significance for the study of radon migration and exhalation in granulated porous media.

Modeling and experimental examination of water level effects on radon exhalation from fragmented uranium ore.

In this study, a one-dimensional steady-state mathematical model of radon transport in fragmented uranium ore was established according to Fick's law and radon transfer theory in an air-water interface. The model was utilized to obtain an analytical solution for radon concentration in the air-water, two-phase system under steady state conditions, as well as a corresponding radon exhalation rate calculation formula. We also designed a one-dimensional experimental apparatus for simulating radon diffusion migration in the uranium ore with various water levels to verify the mathematical model. The predicted results were in close agreement with the measured results, suggesting that the proposed model can be readily used to determine radon concentrations and exhalation rates in fragmented uranium ore with varying water levels.