The weaning male Wistar rats were fed diets with 0.2, 2.0 and 5.0 ppm as Na2SeO4 respectively for 7 weeks. On each Se level, rats were divided into groups with or without supplementation of vitamin E and DL-methi-onine (VE-Met) and possible metabolic interactions of VE-Met to dietary Se at different levels in relation to the detoxification mechanism were ob- served. The results showed that only rats in unsupplemented, 5 ppm Se-diet group exhibited distinct toxic manifestations, and supplementation of VE-Met to this group gave effective protection against the toxic action. In the supplemented group Se content of blood, liver, kidneys and skeletal muscle of the experimental animals was decreased, while the excretory rate of urinary trimethylselenonium ion was increased to a level of 33% in contrast to 22% in the unsupplemented group (P

Objective To explore the CT features of gastrointestinal tract diospyrobezoar and its complications,to improve the recognition. Methods The plain CT scan of 36 patients with gastrointestinal tract diospyrobezoar confirmed by gastroscope and surgery were analyzed retrospectively.Results The number and location of diospyrobezoar showed by CT were consistent with the results of gastroscope and surgery.There were 1 1 cases of stomach diospyrobezoar,1 9 cases of small intestine diospyrobezoar,and 6 cases of stomach and small intestine diospyrobezoar.32 cases were solitary lesion,and 4 cases were multiple lesions.A total of 41 diospyrobezoars were removed, most of which were wel-l defined ovoid mass.3 1 lesions presented mottled internal gas bubbles with high-density encapsulating wall.6 lesions showed mottled gas pattern without encapsulating wall.4 lesions showed uneven high density.Over time,1 lesion moved in the digestive tract and the boundary and density were changed.Complications:gastric and duodenal diospyrobezoar accompanied by gastric retention,which manifested as a significant expansion of the gastric cavity effusion.Small intestine diospyrobezoar was accompanied by small bowel obstruction,which showed that the proximal intestinal tube of the diospyrobezoar was obviously dilated,and the distal intestine was suddenly collapsed.There was a focal transition zone between them.Conclusion Gastrointestinal tract diospyrobezoar has a variety of CT manifestations,of which oval shape,clear boundary,uneven mass composed of gas and soft tissue are common.

Objective To investigate the separation efficiency of three physical separation methods for gaseous ¹⁴C, namely membrane separation, adsorption separation, and low-temperature separation, to screen for the optimal separation method, and to provide a reference for the separation and enrichment of ¹⁴CO₂ in online monitoring of ¹⁴C. Methods The experimental plan was designed, and three devices were constructed for separation and purification experiments. The purity, recovery rate, and separation time of CO₂ separated by the three methods were analyzed. Results All the three methods achieved the separation of CO₂. Under certain conditions, 20 mL of sample gas was obtained. The separation time of membrane separation method was 0.5 hour, CO₂ gas with a sample purity of 0.0486%-0.0488%VOL was obtained, and the recovery rate was only 2.5%−12.7%. The separation time of MOF material adsorption separation method was 24−30 hours, CO₂ gas with a sample purity of 20.2%−47.5%VOL was obtained, and the recovery rate was 57.3%−63.2%. The separation time of low-temperature separation method was 3 hours, CO₂ gas with a sample purity of 96.0%−99.8%VOL was obtained, and the recovery rate was 81.5%−92.5%. Conclusion The purity and recovery rate of CO₂ with low-temperature separation method were higher compared to membrane separation method and MOF material adsorption separation method. The separation time of low-temperature separation method was moderate. The low-temperature separation method can provide a reference for the enrichment technology of ¹⁴C in the rapid measurement of gaseous ¹⁴C effluent.

Objective Nowadays, radioactive xenon isotopes, including ^131mXe, ^133mXe, ¹³³Xe, and ¹³⁵Xe, are primarily released into the atmosphere through various reactor operation and major accidents of reactors. To improve the online monitoring capability of xenon in nuclear facilities and their gaseous effluents, a highly sensitive online xenon monitoring system was developed to monitor, warn, and alarm the activity concentration of radioactive xenon. Methods The online monitoring system for radioactive xenon gas in nuclear facilities was established using xenon membrane separation and concentration, xenon high-efficiency selective adsorption, and low-background gamma-ray spectrometry analysis methods. Results Under the operation mode of one-hour sampling and one-hour measuring, the minimum detectable activity concentration of the radioactive xenon online monitoring system for ¹³³Xe was approximately (1.43 ± 0.03) Bq/m³. Conclusion This system can be effectively used for online monitoring of xenon activity concentration in nuclear facilities such as nuclear power plants and isotope production reactors, as well as in gaseous effluents. It helps improve the safety level of personnel, the environment, and nuclear facilities.