Objective Focusing on the problem such as slow scanning speed, complex system design and low light efficiency, a new parallel confocal 3D profile detecting method based on optical fiber technology, which realizes whole-field confocal detecting, is proposed. Methods The optical fiber plate generates an 2D point light source array, which splits one light beam into N2 subbeams and act the role of pinholes as point source and point detecting to filter the stray light and reflect light. By introducing the construction and working principle of the multi-beam 3D detecting system, the feasibility is investigated. Results Experiment result indicates that the optical fiber technology is applicable in rotation. The measuring parameters that influence the detecting can easily be adapted to satisfy different requirments of measurement. Compared with the conventional confocal method, the parallel confocal detecting system using optical fiber plate is simple in the mechanism, the measuring field is larger and the speed is faster.

Objective:To assess the changes of selenium nutrition of school-age children in Kashin-Beck disease (KBD) areas of Linzhou County, Lhasa City and Xietongmen County, Shigatse City in Tibet Autonomous Region (referred to as Tibet), and provide a scientific basis for evaluating the effectiveness of prevention and control measures.Methods:According to the historical condition of KBD, a total of 344 children's hair samples were collected to determine the content of selenium in Kazi (KBD area) and Jiangxia townships (non-KBD area) of Linzhou County in 2013 and 2021, Renqinze (KBD area) and Tongmen townships (non-KBD area) of Xietongmen County in 2015 and 2021.Results:Compared to 2013/2015, in 2021, the hair selenium level of children in the four townships increased ( P < 0.001). The selenium nutritional level of more than 90% of the children reached medium or above (hair selenium > 0.25 μg/g) in 2021. The hair selenium levels of girls in the two KBD areas (Kazi and Renqinze townships) were lower than those of boys ( Z = - 2.83, - 2.83, P < 0.05). Conclusions:The selenium nutrition level of school-age children in KBD areas in Linzhou and Xietongmen counties has increased rapidly in recent years. However, the selenium nutrition level of girls is significantly lower than that of boys. It is necessary to strengthen prevention, controlling and monitoring, and to further improve the dietary structure of school-age children through the joint efforts of families and schools, to increase the proportion of exogenous high selenium food intake.