Objective To summarize the key precautions in the determination of nitrogen oxides (nitric oxide and nitrogen dioxide) in the workplace air and to explore potential optimization items in the national standard analytical method. Methods According to GBZ/T 160.29-2004 Methods for Determination of Inorganic Nitrogen Compounds in the Air Workplace, comparative experiments were conducted to evaluate and optimize critical technical parameters of the standardized method, including the oxidation efficiency of oxidation tubes and the preparation and storage of absorption solutions. The application details of the standard method were refined. Results The concentrations of nitrogen oxides (nitric oxide and nitrogen dioxide) were expressed as nitrogen dioxide equivalents. During calibration, the flow calibrator should be connected to the upstream of the air sampler, and the sampling system should undergo an air tightness check. Each batch of oxidation tubes should be validated before use. Before sampling, both end caps should be removed and the tube should be equilibrated for one hour in a clean environment with 30.00%-70.00% relative humidity. The prepared absorption stock solution in this method can be stored at 4 ℃ for up to 96 days. Commercial porous plate absorption tubes must be batch-validated before use. The sampling flow rate during sampling should be consistent with that specified in the standard method. After sampling, collected samples should be sealed in 10.00 mL amber glass bottles with screw caps and stored at 4 ℃ for up to 120 hours. Conclusion This study summarizes precautions for the sampling, detection, and calculation of nitrogen oxides (nitric oxide and nitrogen dioxide)in workplace air to strengthen quality control. Experimental optimizations of oxidation tube conditioning, absorption stock solution preparation and preservation, and sample storage conditions and durations may provide references for diversifying and simplifying the detection process, which facilitate the practical application in actual work.

Objective: To investigate the prevalence of hyperactivity behavior in children aged 3-6 in Yunnan Province, to explore its relationship with neuropsychological development, so as to provide clues for early prevention and intervention of attention deficit hyperactivity disorder (ADHD) in children. Methods: A total of 1 321 children aged 3 to 6 from 10 kindergartens in 5 prefectures (cities) of Yunnan Province were selected by stratified random sampling method from October 2022 to May 2023. Teacher Rating Scale (TRS) was used to investigate childrens hyperactive behavior and coexistent behavior. A qualified evaluator applied the Developmental Scale for Children Aged 0-6 Years to assess the development of 5 ability areas of gross motor movement，fine movement，adaptive ability，language and social behavior. Statistical analysis was performed using Wilcoxon rank sum test and χ2 test. Binary Logistic regression was applied to analyze the score of their hyperactivity behavior and its relationship with other behavior problems and neuropsychological development. Results: The detection rate of hyperactivity behavior was 8.6% in children aged 3 to 6 years, 12.8% in boys and 4.1% in girls (χ2=31.53, P<0.01). The detection rate of hyperactivity in 3yearold children was 13.9%, which was higher than that in 4yearold (9.2%) and 5yearold children (7.0%) (χ2=8.73, P<0.05). The detection rate of inattentionpassivity of rural children (14.6%) was higher than that of urban children (5.9%) (χ2=22.23, P<0.01). Binary Logistic regression analysis showed that the higher the level of adaptive development, the lower the risk of hyperactivity (OR=0.58, 95%CI=0.39-0.86), the higher the risk of hyperactivity (OR=0.57, 95%CI=0.35-0.91), the higher the risk of conduct problems (OR=0.57, 95%CI=0.37-0.87), inattentionpassivity (OR=0.49, 95%CI=0.33-0.74) were also at lower risk (P<0.05). Children with higher levels of fine motor development had a lower risk of inattentionpassivity (OR=0.59, 95%CI=0.37-0.93, P<0.05). Conclusions Hyperactivity in boys and inattentionpassivity in rural children requires more attention. It is necessary to strengthen childrens early adaptive ability and fine motor training to prevent hyperactive behavior and inattention.

Since the outbreak of COVID-19, it has spread rapidly throughout the country and even in the world. As a first tier city, Guangzhou is also the South Gate of China, with large population mobility and severe and complex prevention and control situation. Guangzhou CDC, together with Tencent and Alibaba Cloud, has made full use of its artificial intelligence technology to carry out a series of practices in case transmission chain analysis, close contact and other key personnel management, front-line staff prevention and control skills training and convenience services. Through the application of artificial intelligence in different scenarios, the difficulties and challenges in the prevention and control are solved, and the speed of epidemic prevention and control is increased.

Since the outbreak of COVID-19, it has spread rapidly throughout the country and even in the world. As a first tier city, Guangzhou is also the South Gate of China, with large population mobility and severe and complex prevention and control situation. Guangzhou CDC, together with Tencent and Alibaba Cloud, has made full use of its artificial intelligence technology to carry out a series of practices in case transmission chain analysis, close contact and other key personnel management, front-line staff prevention and control skills training and convenience services. Through the application of artificial intelligence in different scenarios, the difficulties and challenges in the prevention and control are solved, and the speed of epidemic prevention and control is increased.