A method for the digestion of food samples by using PTFE closed-vessel microwave oven has been established. Six elements in the solution were determined by ICP-AES. The effects of various acid mixtures and digestion time were studied. 0.2 g of powdered samples dried for four hours at 80℃ were weighed and put into 50 ml PTFE digestion vessels. 2 ml of 70% HNO3 and 1 ml of 30% H2O2 were added to each sample digestion vessel. The screw caps were tightened and placed on the microwave oven PTFE turntable for 3 min at 100% full power (500W). When digestion was finished, the vessels were cooled for 10 min in a medical refrigerator at -25℃. The sample solutions were diluted to 25 ml with subboiling water. The contents of Ca, Mg, Mn, Fe, Zn and Cu in 3 standard reference materials were determined by ICP-AES. The results are in good agreement with certified values.

Objective:To explore the mindfulness level and self-management behaviors in young and middle-aged maintenance hemodialysis (MHD) patients, and to analyze the correlation between them.Methods:From August to November 2020, convenience sampling was used to select 170 young and middle-aged MHD patients admitted to the Blood Purification Center of People's Hospital of Hunan Province as the research object. The patients were investigated using the General Information Questionnaire, Five Facet Mindfulness Questionnaire (FFMQ) and Hemodialysis Self-Management Instrument (HD-SMI) . A total of 170 questionnaires were distributed, and 165 valid questionnaires were recovered, with a valid recovery rate of 97.06%.Results:Among 165 young and middle-aged MHD patients, the total scores of FFMQ and HD-SMI were (116.12±14.82) and (57.72±10.72) respectively. Pearson correlation analysis showed that the FFMQ total score and each dimension score were all positively correlated with the HD-SMI total score and each dimension score ( P<0.05) . Conclusions:The level of mindfulness and self-management behaviors of young and middle-aged MHD patients were in the middle level. Medical and nursing staff should conduct mindfulness interventions for young and middle-aged MHD patients to improve patients' initiative and further improve their self-management behaviors.