Biomimetic mucus-lubricated surfaces are highly effective in reducing drag, but achieving stable mucus adsorption on microstructures remains a challenge. The loach (Paramisgurnus dabryanus) can reduce frictional resistance during swimming. Using the water tunnel experimental platform, it was calculated that loach skin with mucus achieves a 28% drag reduction compared to mucus-free skin. Inspired by the ultra-smooth and flexible body surface of loach skin, this study establishes a novel biomimetic lubricating surface design that utilizes flexible V-microgrooves (FV) to firmly trap the mucus, thereby enhancing lubrication and reducing friction. The mucus and flexible V-microgrooves (M&FV) aim to effectively reduce drag while improving the durability of self-lubricating surfaces. To explore the drag reduction mechanism of the model, the V-microgrooves, the high viscosity of the mucus, and the low interfacial tension with water were studied. Through numerical simulations, the optimal configuration was identified using the drag reduction rate (DRE) as the primary evaluation criterion. Within 1.5 s, at the flow rate of 1 m/s, the M&FV3 achieved a maximum DRE of 34.64%, and the effective slip length was 3.2 μm. Inside the FV, the mucus volume fraction reached 32.72%, which significantly reduced surface pressure resistance by 31.57% and viscous resistance by 40.83%. Additionally, the increased boundary layer thickness promoted velocity slip, further enhancing drag reduction. These findings highlight the potential of integrating bionic mucus and microgrooves into self-lubricating surfaces, providing valuable insights for advancing biological lubrication in engineering applications.

Previous studies have demonstrated that slightly acidic electrolyzed water (SAEW) treatment can enhance rice seed growth and promote the accumulation of γ-aminobutyric acid (GABA), a bioactive compound. However, the underlying mechanisms remain unexplored. This study systematically investigated the effects of pH and available chlorine concentration (ACC) of SAEW on rice seed germination and GABA biosynthesis. The changing trends were monitored within 7 days. The results revealed that the treatment group with moderate pH (S2, pH 5.74 ± 0.04) showed significantly higher GABA accumulation (71.27 ± 0.45 mg/100 g) compared with S1 (pH 5.04 ± 0.03) and S3 (pH 6.38 ± 0.04) (p < 0.05). Furthermore, a positive correlation was observed between ACC levels and GABA accumulation, suggesting that ACC plays a crucial regulatory role in rice seed germination. These findings were further substantiated by monitoring the enzymatic activity of glutamate decarboxylase (GAD) throughout the germination process. Notably, while higher ACCs negatively impacted rice seed growth, pH variations within the tested range showed no adverse effects on seed development. The results show that optimal SAEW parameters, considering both pH and ACC, should be carefully determined for practical applications in rice seed production.