Effects of earthworms on antibiotic resistance genes in different soil-plant systems.

Earthworms play an important role in the soil environment. To explore the difference in earthworms influence on various media in different soil-plant systems, the abundance of tetracycline, sulfonamide and quinolone resistance genes and the structure of the bacterial community were analysed from five different media including non-rhizosphere soil, rhizosphere soil, phyllosphere, root endophytes and earthworm intestine by real-time quantitative PCR and high-throughput 16S rRNA sequencing. Studies have shown that earthworms can reduce the absolute abundance of antibiotic resistance genes (ARGs) in non-rhizosphere soil. Root endophytes in the soil-cabbage system and rhizosphere soil in the soil-setaria system had the same findings. Earthworms can change the bacterial community structure, especially that of Proteobacteria and Cyanobacteria in the phyllosphere and root endophytes. Redundancy analysis (RDA) results that bacterial community change was the main factor affecting ARGs. In addition, earthworms increased the proportion of Cyanobacteria in root endophytes, and Cyanobacteria was significantly positively correlated with sul3. This study provides a scientific basis for controlling the migration and diffusion of ARGs and reducing environmental risks in soil-plant systems in the future.

Prevalence of social anxiety disorder and symptoms among Chinese children, adolescents and young adults: A systematic review and meta-analysis.

The objective of the study is to provide a reliable estimate of the pooled prevalence of social anxiety disorder (SAD) and social anxiety symptoms (SAS) among children, adolescents, and young adults (CAYA) in China. Meta-analysis is used to provide pooled-prevalence rate of SAD and SAS. Literature searches were conducted in both English and Chinese databases from the database's inception to April 2019. Eleven studies were identified for SAD, and 17 were included for SAS. The results revealed a pooled prevalence of SAD of 2.1% (95% CI: 1.2-3.8%) with high between-studies heterogeneity (Q = 1,055.2, I 2 = 99.1%, p < 0.001). The pooled prevalence estimate of SAS was 23.5% (95% CI: 18.6-29.3%), also with significant heterogeneity (Q = 1,019.3, I 2 = 98.4%, p < 0.001). Different diagnostic tools or self-report scales reported significant different prevalence of SAD or SAS. Further analysis stratified by gender, age, sampling methods, economic status, and risk of bias were performed. Limitations include the high level of heterogeneity between studies, inadequate number of the studies, and significant differences in prevalence caused by measurements. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020149591, identifier: PROSPERO CRD42020149591.

Effects of composting pig manure at different mature stages on ARGs in different types of soil-vegetable systems.

Aerobic composting is considered as an economically as well as environmentally friendly technology that prevents the diffusion of ARGs and ARBs from manure to farmland soil, on which many studies have been conducted. However, the transmission route and potential ecological risks of ARGs in soil-vegetable systems after application of manure at different maturity stages remain unclear. Therefore, through a pot experiment, this study analyzed the effects of manure composted from livestock excrement on ARGs and microbial community in different soil-vegetable systems, taking leafy plants (Shanghai green) and tuber plants (carrot) as examples. It was noted that the highly matured manure could reduce the ARGs contamination in soil and crops, and the ARGs in soil tended to accumulate in the direction of plant roots. The edible part of crops often had a more serious ecological risk of ARGs, and the potential pathogenic bacteria and ARGs could harm human health through exposure and dietary routes. In summary, this study provides new evidence for the transmission of ARGs in soil-vegetable systems with different mature stages of manure and highlights the potential safety risks of the transfer of antibiotic resistance from manure to soil and ultimately to the human food chain.

Fatigue Resistance and Cracking Mechanism of Semi-Flexible Pavement Mixture.

Semi-flexible pavement (SFP) is widely used in recent years because of its good rutting resistance, but it is easy to crack under traffic loads. A large number of studies are aimed at improving its crack resistance. However, the understanding of its fatigue resistance and fatigue-cracking mechanism is limited. Therefore, the semi-circular bending (SCB) fatigue test is used to evaluate the fatigue resistance of the SFP mixture. SCB fatigue tests under different temperature values and stress ratio were used to characterize the fatigue life of the SFP mixture, and its laboratory fatigue prediction model was established. The distribution of various phases of the SFP mixture in the fracture surface was analyzed by digital image processing technology, and its fatigue cracking mechanism was analyzed. The results show that the SFP mixture has better fatigue resistance under low temperature and low stress ratio, while its fatigue resistance under other environmental and load conditions is worse than that of asphalt mixture. The main reason for the poor fatigue resistance of the SFP mixture is the poor deformation capacity and low strength of grouting materials. Furthermore, the performance difference between grouting material and the asphalt binder is large, which leads to the difference of fatigue cracking mechanism of the SFP mixture under different conditions. Under the fatigue load, the weak position of the SFP mixture at a low temperature is asphalt binder and its interface with other materials, while at medium and high temperatures, the weak position of the SFP mixture is inside the grouting material. The research provides a basis for the calculation of the service life of the SFP structure, provides a reference for the improvement direction of the SFP mixture composition and internal structure.