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为扩大椰子油的应用范围，以精制冷榨椰子油为油相，Tween 80为乳化剂，无水乙醇为助乳剂，采用超声乳化法制备椰子油纳米乳液。以椰子油纳米乳液平均粒径及多分散指数（PDI）为指标，通过单因素实验和正交实验对椰子油纳米乳液制备工艺条件进行优化，并对制备的椰子油纳米乳液的类型进行鉴定。结果表明：椰子油纳米乳液最佳制备工艺条件为超声功率500 W、超声时间20 min、油乳质量比1∶ 1.5、油乳混合物与水质量比2∶ 8，在此条件下制得的纳米乳液平均粒径和PDI分别为131.0 nm和0.27；制得的椰子油纳米乳液为水包油（O/W）型。该工艺条件下制得的椰子油纳米乳液粒径小且均匀，且O/W型的椰子油纳米乳液拓宽了椰子油的应用范围。In order to expand the application of coconut oil, coconut oil nanoemulsion was prepared by ultrasonic emulsification with refined cold pressed coconut oil as the oil phase, Tween 80 as the emulsifier and absolute ethanol as the co-emulsifier. The preparation process of coconut oil nanoemulsion was optimized by single factor experiment and orthogonal experiments using the average particle size of coconut oil nanoemulsion and polydispersity index (PDI) as indicators, and the type of coconut oil nanoemulsion prepared was identified. The results showed that the optimal process conditions were ultrasonic power 500 W, ultrasonic time 20 min, mass ratio of oil to emulsion 1∶ 1.5, mass ratio of oil-emulsion mixture to water 2∶ 8. Under the optimal conditions, the average particle size and PDI of the nanoemulsion prepared were 131.0 nm and 0.27, respectively. The prepared coconut oil nanoemulsion was oil in water (O/W) type. In summary, the coconut oil nanoemulsion prepared has small and uniform particle size and the O/W type of coconut oil nanoemulsion broadens the application range of coconut oil.

Objectives: To analyze the mode of school physical activity, the relationship with obesity, and participation willingness and behavior in the relationship between modes of school physical activity and BMI in students with overweight or obesity. Design: Cross‐sectional study. Sample: Data from the 2014 Physical Fitness and Health Surveillance of Chinese School Students was used, wherein physical measurements and questionnaires of 3476 middle school students were collected. Measurements: Physical measurements and questionnaires were completed. Latent profile analysis and mediated effects analysis were conducted using Mplus 8.3 and IBM SPSS 26.0 for data description and statistical analysis. Result: After latent profile analysis divided into poor (9.35%), medium (65.16%), and good (25.49%) groups of school physical activity, among junior middle school students, medium (OR = 0.428, 95% CI = 0.259–0.707, p =.001) and good (OR = 0.448, 95% CI = 0.255–0.718, p =.002) groups were positive for controlling overweight. Among students with overweight or obesity, participation willingness mediated the relationship between the mode of school physical activity and BMI, with effect coefficients of −0.120 (95% CI = −0.264 to −0.016) and −0.240 (95% CI = −0.426 to −0.099). Conclusions: School physical activity modes have a positive effect only on preventing and controlling overweight in junior middle school students. For middle school students with obesity, weight‐specific measures should be considered for their prevention and control. [ABSTRACT FROM AUTHOR]