Objective To study the effect of magnetic field on serum activity of superoxide dismutase (SOD), content of malon-dialdehyde (MDA)and content of nitric oxide (NO)in patients undergoing operation for pituitary Tumor. Methods Sixteen ASA Ⅰor Ⅱ patients undergoing pituitary tumor surgery under general anesthesia were randomly divided into 2 groups (n=8 each): magnetic field group (M) and control group (C). Patients in magnetic field group were exposed in 150 mT magnetic field during the operation period.Blood samples were taken from radial artery for determination of serum SOD,MAD and NO before induction of anesthesia(T_0, baseline),after induction(T_1),70 min after induction(exposed in magnetic field for 60 min) (T_2)and 130 min after induction (exposed in magnetic field for 120 min) (T_3). Results There was no significant difference between the two groups in age, sex (M/F ratio),body weight,body height,duration of operation and duration of anaesthesia.The serum activity of SOD and content of NO were significantly higher at T_3 in group M than that in group C,and the serum content of MDA was lower at T_3 in group M than that in group C. Conclusions The magnetic field not only increases serum SOD activity and the content of NO in patient undergoing operation for pituitary tumor,but also reduces the content of MDA in them.

Objective:To analyze the wall thickness of C-shaped canals in permanent mandibular second molars.Methods:40 ex-tracted permanent mandibular second molars with C-shaped root were collected from native Chinese and were scanned by micro-CT scan-ner.The specimens were reconstructed three-dimensionally by software Mimics 10.01.The roots were sliced from cemento-enamel junc-tion (CEJ)to apex with 1 mm intervals.The cross-sectional root canal configurations were classified into 5 types according to the Fan's Classification.The minimum buccal wall thickness (MBWT),minimum lingual wall thickness(MLWT)and their locations,as well as the wall thickness at the mesial and distal reference sites were detected.Two-way ANOVA and post hoc LSD-t tests were used to com-pare the mean thickness at 4 sides.Results:Among 370 cross-sections of 40 C-shaped roots,C1,C2 and C3 canals were observed on 126(34.1%),46 (12.4%)and 160 (43.2%)sections respectively.Except at the 10 mm level,the mean MLWT was always lower than MBWT;and the MLWT and MBWT were always lower than the wall thickness at the mesial and distal reference sites.The differ-ence was statistically significant (P <0.05)along the root length above the 12 mm level.The MBWT of the C2 and C3 canals was more likely located at the mesial region,and the MBWT of the C1 and the MLWT of C1,C2 and C3 was more frequently located at the center region.Conclusion:The lingual wall of C-shaped canal in mandibualr second molars was the thinnest zone among four sides,and care should be taken during root canal instrumentation and post space preparation to avoid perforation.

ObjectiveTo investigate the dietary preference and nutritional knowledge needs of the elderly people who dined at meal service sites. MethodsUsing the form of stratified and convenience sampling method with self-designed questionnaire was used， in November 2021， to select 700 elderly people who dine at meal service sites in 7 jurisdictions in Shanghai were selected， and a self-designed questionnaire was used to investigate the basic information. Results91.64% of the elderly surveyed would eat at relatively fixed meal service sites， and the total Dietary Diversity Score （DDS9） was 3.56±1.46. 41.45% of the elderly with diseases preferred unhealthy cooking methods. Only 8.03% of the surveyed seniors said they were unwilling to accept targeted and personalized nutrition tips and reminders. Multivariate logistic regression analysis showed that the probability reaching the “understanding” level of “Food Guide Pagoda for Chinese Residents” and “Four Principles Recommended by the Core Dietary Guidelines for the Elderly” was different in the elderly with different education levels. The willingness of the elderly to expect to receive different nutrition tips and reminders was related to whether they cared about the corresponding contents. There was a statistically significant difference （P<0.05） among the elderly who were concerned about different health problems in terms of the willingness to receive different nutritional tips. There were significant differences in the proportion of elderly people with different health status for intervention （χ²=5.402， P<0.05）. ConclusionThe elderly who dine at meal service sites are highly dependent on the sites， have a low level of dietary diversification， and do not have a high degree of understanding of nutrition-related knowledge， and have a high demand for targeted nutritional interventions. Nutritional interventions for the sick elderly should be piloted through multiple channels.