PGN-202

Ensuring the stability of soil organic carbon (SOC) is vital for effective long-term carbon storage in forest ecosystems. While nanoparticles (NPs) have shown the potential to enhance SOC stability and reduce cumulative carbon mineralization rates (CCMR) in agricultural soils, their effects on forest soils remain largely unexplored. This study addresses this gap through an incubation experiment that evaluated the impact of silicon nitride nanoparticles (Si₃N₄-NPs) at varying concentrations [control, 0 mg kg^-1 (NP₀); 50 mg kg^-1 (NP₁); 100 mg kg^-1 (NP₂)] on SOC stability, CCMR, enzymatic activities, and microbial diversity across three forest ecosystems in the Dinghushan region of Guangdong, China: coniferous forest (CF), mixed conifer-broadleaf forest (MCBF), and monsoon evergreen broadleaf forest (MEF). The results revealed that Si₃N₄-NP application at the NP₂ concentration significantly reduced CCMR by 40.82 % compared to the control (NP₀). Moreover, NP₂ substantially decreased the activities of key soil enzymes: β-glucosidase by 13.81 %, N-acetylglucosaminidase by 32.62 %, cellobiohydrolase by 59.12 %, and phenol oxidase by 26.40 %, relative to NP₀. The NP₂ treatment also enhanced total SOC retention by 24.62 % compared to NP₀. Within SOC fractions, NP₂ significantly impacted the less labile (C3) and non-labile (C4) fractions, which increased by 46.83 % and 57.84 %, respectively, compared to NP₀. Meanwhile, the very labile C (C1) and labile C (C2) fractions showed non-significant changes. Furthermore, the Si₃N₄-NP applications induced distinct shifts in bacterial (Actinobacteriota) and fungal (Ascomycota) microbiomes, which correlated significantly with CCMR and total SOC. These findings indicate that Si₃N₄-NPs improve SOC stability and reduce mineralization in forest soils. However, field-scale validation is essential to assess the long-term impacts of Si₃N₄-NPs on microbial communities and overall ecosystem functioning. This study highlights the significance of NP concentration and forest type in developing effective strategies for SOC management to mitigate climate change.

Liver inflammatory diseases are marked by serious complications. Notably, nicardipine (NCD) has demonstrated anti-inflammatory properties, but its benefits in liver inflammation have not been studied yet. However, the therapeutic efficacy of NCD is limited by its short half-life and low bioavailability. Therefore, we aimed to evaluate the potential of NCD-loaded chitosan nanoparticles (ChNPs) to improve its pharmacokinetic profile and hepatic accumulation. Four formulations of NCD-ChNPs were synthesized and characterized. The optimal formulation (NP2) exhibited a mean particle diameter of 172.6 ± 1.94 nm, a surface charge of +25.66 ± 0.93 mV, and an encapsulation efficiency of 88.86 ± 1.17 %. NP2 showed good physical stability as a lyophilized powder over three months. It displayed pH-sensitive release characteristics, releasing 77.15 ± 5.09 % of NCD at pH 6 (mimicking the inflammatory microenvironment) and 52.15 ± 3.65 % at pH 7.4, indicating targeted release in inflamed liver tissues. Pharmacokinetic and biodistribution studies revealed that NCD-ChNPs significantly prolonged NCD circulation time and enhanced its concentration in liver tissues compared to plain NCD. Additionally, the study investigated the protective effects of NCD-ChNPs in thioacetamide-induced liver injury in rats by modulating the NFκB/NLRP3/IL-1β signaling axis. NCD-ChNPs effectively inhibited NFκB activation, reduced NLRP3 inflammasome activation, and subsequent release of IL-1β, which correlated with improved hepatic function and reduced inflammation and oxidative stress. These findings highlight the potential of NCD-ChNPs as a promising nanomedicine strategy for the treatment of liver inflammatory diseases, warranting further investigation into their clinical applications, particularly in hypertensive patients with liver inflammatory conditions.