Methamphetamine use in typical Chinese cities evaluated by wastewater-based epidemiology.

Methamphetamine has become one of the most widely used illicit drugs in China. To understand the current situation in China, the prevalence and consumption of methamphetamine were estimated through wastewater-based epidemiology (WBE) in the present study. Methamphetamine concentrations ranged from 42.6 ng/L (Harbin) to 700 ng/L (Xi'an) in influent wastewater samples collected from 27 wastewater treatment plants (WWTPs) in 22 Chinese cities. The estimated consumption of methamphetamine was 23.0 (Dingxi) to 376 (Xi'an) mg/day/1000 inhabitants with a mean value of 157 mg/day/1000 inhabitants. The annual consumption in 2018 was estimated to be 84 tons (95% confidence interval, 44-136), which was 26% lower than that in 2014. The prevalence of methamphetamine use was 0.64% (95% confidence interval, 0.18-1.25), indicating that more than five million people used methamphetamine in 2018. Although drug abuse is common in the country, the consumption showed a different spatial pattern, with the highest values in Central China and the lowest use in Northeast China, so drug use is still considered a geographic and culture-dependent behaviour. The results indicated that WBE can not only be used to assess the trends of illicit drug use, but also to analyse the spatial differences in the whole country, which will provide complementary evidence for the prevention and control of methamphetamine use.

[Adaptation mechanisms of alpine plants photosynthetic apparatus against adverse stress: a review].

Photosynthesis is one of the vital physiological processes easily affected by environmental changes. As a plant group growing in specific low temperature and strong irradiance environment, the photosynthetic apparatus of alpine plants have developed special morphologically and physiologically mechanisms in adapting to this extreme adverse environment. However, due to the high heterogeneity of habitats, there exist great differences in the photo-protection and adaptation mechanisms among different alpine plants. This paper reviewed the recent researches about the morphology and ultramicro-anatomical structure of the chloroplasts in photosynthetic apparatus of alpine plants and the photo-protection and adaptation mechanisms of the plants, and proposed the further research directions on the physiological adaptation of the photosynthesis of alpine plants.