Temporal rich club phenomenon and its formation mechanisms.

The temporal rich club (TRC) phenomenon is widespread in real systems, forming a tight and continuous collection of the prominent nodes that control the system. However, there is still a lack of sufficient understanding of the mechanisms of TRC formation. Here we use the international N-nutrient trade network as an example of an in-depth identification, analysis, and modeling of its TRC phenomenon. The system exhibits a statistically significant TRC phenomenon, with eight economies forming the cornerstone club. Our analysis reveals that node degree is the most influential factor in TRC formation compared to other variables. The mathematical evolution models we constructed propose that the TRC in the N-nutrient trade network arises from the coexistence of degree-homophily and path-dependence mechanisms. By comprehending these mechanisms, we introduce a different perspective on TRC formation. Although our analysis is limited to the international trade system, the methodology can be extended to analyze the mechanisms underlying TRC emergence in other systems.

Impact of the Russia-Ukraine Conflict on International Staple Agrifood Trade Networks.

The Russia-Ukraine conflict is a growing concern worldwide and poses serious threats to regional and global food security. Using monthly trade data for maize, rice, and wheat from 2016/1 to 2023/12, this paper constructs three international crop trade networks and an aggregate international food trade network. We aim to examine the structural changes following the occurrence of the Russia-Ukraine conflict. We find significant shifts in the number of edges, average in-degree, density, and efficiency in the third quarter of 2022, particularly in the international wheat trade network. Additionally, we have shown that political reasons have caused more pronounced changes in the trade connections between the economies of the North Atlantic Treaty Organization and Russia than with Ukraine. This paper could provide insights into the negative impact of geopolitical conflicts on the global food system and encourage a series of effective strategies to mitigate the negative impact of the conflict on global food trade.

The health risk of acetochlor metabolite CMEPA is associated with lipid accumulation induced liver injury.

Liver injury may cause many diseases, such as non-alcoholic fatty liver disease (NAFLD). Acetochlor is one of the representative chloroacetamide herbicides, and its metabolite 2-chloro-N-(2-ethyl-6-methyl phenyl) acetamide (CMEPA) is the main form of exposure in the environment. It has been shown that acetochlor can cause mitochondrial damage of HepG2 cells and induce apoptosis by activating Bcl/Bax pathway (Wang et al., 2021). But there has been less research on CMEPA. we explored the possibility of CMEPA and liver injury through biological experiments. In vivo, CMEPA (0-16 mg/L) induced liver damage in zebrafish larvae, including increased lipid droplets, changes in liver morphology (>1.3-fold) and increased TC/TG content (>2.5-fold). In vitro, we selected L02 (human normal liver cells) as the model, and explored its molecular mechanism. We found that CMEPA (0-160 mg/L) induced apoptosis (similar to 40%), mitochondrial damage and oxidative stress in L02 cells. CMEPA induced intracellular lipid accumulation by inhibiting AMPK/ACC/CPT-1A signaling pathway and activating SREBP-1c/FAS signaling pathway. Our study provides evidence of a link between CMEPA and liver injury. This raises concerns regarding the health risks of pesticide metabolites to liver health.

Effect of time and temperature on stability of progestagens, testosterone and cortisol in Asian elephant blood stored with and without anticoagulant.

The value of biological samples collected in the field is compromised if storage conditions result in analyte degradation, especially in warmer climates like Thailand. We evaluated the effects of time and temperature on immunoactive steroid hormone stability in Asian elephant (Elephas maximus) blood stored with and without an anti-coagulant before centrifugation. For each elephant (5 male, 5 female), whole blood was aliquoted (n = 2 ml each) into 13 red top (without anticoagulant) or purple top (with anticoagulant) tubes. One tube from each treatment was centrifuged immediately and the serum or plasma frozen at -20°C (Time 0, T0). The remaining 12 aliquots were divided into stored temperature groups: 4°C, room temperature (RT, ~22°C), and 37°C, and centrifuged after 6, 24, 48 and 62 h of storage. Serum and plasma concentrations of progestagens in females, testosterone in males and cortisol in both sexes were quantified by validated enzyme immunoassays. Steroid concentration differences from T0 were determined by a randomized complete block ANOVA and Dunnett's tests. The only evidence of hormone degradation was cortisol and testosterone concentrations in serum stored at 37°C. Testosterone concentrations declined by 34% at 48 h and 52% at 62 h, cortisol was decreased by 19% after 48 h and 27% after 62 h at 37°C, respectively. None of the other aliquots displayed significant changes over time at any temperature. In conclusion, steroids appear to be stable in blood for nearly 3 days at room or refrigeration temperatures before centrifugation; steroids in samples with ethylenediaminetetraacetic acid were particularly stable. However, warmer temperatures may negatively affect steroids stored without anti-coagulant, perhaps due to red blood cell metabolism. Thus, under field conditions with no access to cold or freezer temperatures, collection of plasma is a better choice for elephants up to at least 62 h before centrifugation.