Acute toxicity, biochemical and transcriptomic analysis of Procambarus clarkii exposed to avermectin.

BACKGROUND: Pesticides are extensively applied globally. Pesticide residues induce calamitous effects on the environment and untargeted organisms. Public concerns for the safety of freshwater organisms and the challenges posed by aquatic contaminants remain high. In the present study, the acute toxicity of avermectins (AVMs) to the crayfish, Procambarus clarkii was evaluated. We also evaluated the potential effects of AVM on the biochemical and transcriptomic status of the hepatopancreas and gastrointestinal tract in P. clarkii. RESULTS: The 24, 48, 72, 96 h median lethal concentrations (LC50 ) of AVM on crayfish were 2.626, 1.162, 0.723, 0.566 mg L-1 , respectively. The crayfish were then exposed to 0.65 mg L-1 of AVM for 96 h. AVM significantly altered biochemical parameters including AChE and CAT activities in the hepatopancreas, and AChE, SOD and Na + -K + -ATPase activities in the gastrointestinal tract at several time points. Furthermore, transcriptomic analysis identified 953 and 1851 differentially-expressed genes (DEGs) in the hepatopancreas and gastrointestinal tract, respectively. KEGG enrichment showed that the gene expression profiles of the hepatopancreas and gastrointestinal tract were distinct from each other. The DEGs in the hepatopancreas were mostly enriched with stress-response pathways, while the majority of the DEGs in the gastrointestinal tract belonged to metabolism-related pathways. CONCLUSION: We demonstrated that the AVM induced acute toxicity, oxidative stress, osmoregulation disturbance, neurotoxicity and transcriptome imbalance in crayfish. These findings unraveled the detrimental effects of AVMs exposure on crayfish. © 2022 Society of Chemical Industry.

The Impact of Cooperative Behavior between Social Organizations during the COVID-19 Pandemic Outbreak in Shanghai: A Simulation Approach.

In 2022, a new outbreak of the COVID-19 pandemic created considerable challenges for the Shanghai public health system. However, conventional prevention and control strategies, which only rely on formal organizations, inefficiently decrease the number of infections. Thus, a multi-organization management mode is needed for pandemic prevention. In this paper, we applied a stochastic actor-oriented model (SAOM) to analyze how these social organizations cooperate with others and further identify the mechanism that drives them to create a reliable and sustainable cooperative relationship network from the perspective of social network analysis. The model allowed us to assess the effects of the actor's attributes, the network structure, and dynamic cooperative behavior in RSiena with longitudinal data collected from 220 participants in 19 social organizations. The results indicated that the number of cooperative relationships increased during the pandemic, from 44 to 162, which means the network between social organizations became more reliable. Furthermore, all the hypotheses set in four sub-models were significant (t-ratio < 0.1, overall max t-ratio < 0.25, and e/s > 2). Additionally, the estimated values showed that four factors played a positive role in forming the cooperative relationship network, i.e., all except the "same age group effect (−1.02)". The results also indicated that the social organizations tend to build relationships with more active actors in the community in every time period. This paper is of great significance regarding the innovation of public health system management and the improvement of Chinese grassroots governance.

Microstructural Evolution and Mechanical Properties of a Ni-Based Alloy with High Boron Content for the Pre-Sintered Preform (PSP) Application.

The pre-sintered preform (PSP) is an advanced technology for repairing the Ni-based superalloy blade in a turbine. In general, boron is added to the Ni-based superalloys in small quantities (<0.1 wt.%) to increase boundary strength and cohesivity. Despite this, the effect of high B content (>1.0 wt.%) on the microstructure evolution and mechanical properties in Ni-based superalloys for the PSP application is rarely studied. The variety, composition and evolution of the precipitates during solution heat treatment in the alloy with high B content were determined by EBSD, EPMA and SEM. The results indicate that Cr, W and Mo-rich M5B3 type borides precipitate from the matrix and its area fraction reaches up to about 8%. The area fraction of boride decreases with the prolonging of solution time and the increase of temperature higher than 1120 °C. The borides nearly disappear after solution treatment at 1160 °C for 2 h. The redissolution of boride and eutectic results in the formation of B-rich area with low incipient melting (about 1189 °C). It can bond metallurgically with the blade under the melting point of the blade, which decreases the precipitation of harmful phases of the blade after PSP repairing. The microhardness within the grain in the PSP work-blank first decreases (lower than 1160 °C) and then increases (higher than 1185 °C) with the increase of solution heat treatment temperature due to the dissolving and precipitation of borides. The tensile strength of the combination of PSP work-blank and Mar-M247 matrix at room temperature after solution treatment is related to the area fraction of boride, incipient melting and the cohesion between PSP work-blank and Mar-M247 matrix.