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Based on carbon steel surface corrosion,a study was conducted on multifunction acid water-based surface tolerant coatings. The focus was placed on the effect of antirust components and preparation processes on the coating properties. The barrier property was evaluated and compared with imported counterparts. The results show that when the treatment level of the substrate material surface is St1,the adhesive force of the coatings rises at the beginning and then goes downward as the content of the antirust components keeps increasing. The chelating agent contains active groups which stabilize the substrate surface corrosion,resulting in the adhesion performance of the coatings increasing. The compound rust conversion agent improves the coating adhesive force further by translating the corroded substrate surface complexation. The best preparation process needs to mix at low speed and add the compound rust agent at the end of the steps. The adhesive forces of the coatings on the substrate material surfaces treated at St1 and St3 levels show no difference,and they are larger than 5 MPa. The corrosion resisting properties,resistant to salt water for 1200 h,salt spray for1000 h and ultraviolet aging for 2000 h,are much higher than those of similar imported water-based rust primers. The coatings are suitable for the maintenance of complex steel components in atmospheric environment.

Background: Previous studies have suggested the involvement of epithelium in modulating the contractility of neighboring smooth muscle cells. However, the mechanism underlying epithelium-derived relaxation in airways remains largely unclear. This study aimed to investigate the mechanism underlying epithelium-dependent smooth muscle relaxation mediated by neurotransmitters., Methods: The contractile tension of Sprague-Dawley (SD) rat tracheal rings were measured using a mechanical recording system. Intracellular Ca 2+ level was measured using a Ca 2+ fluorescent probe Fluo-3 AM, and the fluorescence signal was recorded by a laser scanning confocal imaging system. The prostaglandin E 2 (PGE 2 ) content was measured using an enzyme-linked immunosorbent assay kit., Results: We observed that the neurotransmitter acetylcholine (ACh) restrained the electric field stimulation (EFS)-induced contraction in the intact but not epithelium-denuded rat tracheal rings. After inhibiting the muscarinic ACh receptor (mAChR) or cyclooxygenase (COX), a critical enzyme in prostaglandin synthesis, the relaxant effect of ACh was attenuated. Exogenous PGE 2 showed a similar inhibitory effect on the EFS-evoked contraction of tracheal rings. Moreover, ACh triggered phospholipase C (PLC)-coupled Ca 2+ release from intracellular Ca 2+ stores and stimulated COX-dependent PGE 2 production in primary cultured rat tracheal epithelial cells., Conclusions: Collectively, this study demonstrated that ACh induced rat tracheal smooth muscle relaxation by promoting PGE 2 release from tracheal epithelium, which might provide valuable insights into the cross-talk among neurons, epithelial cells and neighboring smooth muscle cells in airways., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/atm-20-5500). The authors have no conflicts of interest to declare., (2021 Annals of Translational Medicine. All rights reserved.)