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Various types of micro-/nanostructures can be fabricated by femtosecond laser irradiation on metal surfaces. It has received extensive attention and research because of its potential application value. In this paper, the effect of laser focusing position on the micro-/nanostructure formation on the surface of a titanium alloy (TC4) was systematically researched. The experimental results show that, in the process of femtosecond laser focusing, a spatial distribution of laser energy with a narrower beam center and a ring around the beam is formed in front of the geometric focus and the distribution of laser energy changes along the laser transmission direction. This property can affect the morphology of the micro-/nanostructure on the surface of irradiated materials. It is believed that the new spatial distribution of laser fluence caused by focusing is due to the nonlinear process of plasma defocus and laser self-focusing caused by multi-photon or tunnel ionization in front of the target by focusing the femtosecond laser. The discovery of the nonlinear characteristics of the focused femtosecond laser and the application of the unique energy spatial distribution to the surface morphology of the fabricated surface put forward a new idea for the direct fabrication of micro-/nanostructures via femtosecond laser, which has certain significance for the development of micro-/nanofabrication technology of femtosecond lasers.

Tripterygium wilfordii Hook. f. is a well-known traditional Chinese medicine used to treat autoimmune diseases. Sesquiterpene pyridine alkaloids (SPAs) are a major class of components found in this herb that have piqued the interest of researchers due to their complex and diverse structures as well as significant biological activities. In this study, ten new SPAs, wilfordatine A–J (1–10), were isolated from the roots of T. wilfordii, along with ten known analogues (11–20). Their structures were primarily elucidated by extensive 1D and 2D NMR spectroscopic analysis. To search for more immunosuppressive ingredients related to the clinical efficacy of T. wilfordii, the total alkaloids (TA) and compounds 4, 5, and 9–16 were tested for their inhibitory effects on nuclear factor-kappa B (NF-κB) pathway in Lipopolysaccharide (LPS) induced HEK293/NF-κB-Luc cells. Among them, TA, compounds 5, 11, and 16 showed potent immunosuppressive activity, with IC50 values of 7.25 μg/mL, 8.75 μM, 0.74 μM, and 15.66 μM, respectively, and no influence on the cell viability at a concentration of 100 μg/mL (TA) or 100 μM (5, 11, and 16). Accordingly, TA, 5, 11, and 16, especially 11, were identified as promising candidates for further investigation into their potential use as immunosuppressive agents.

Tripterygium glycosides tablets (TGTs) are widely used in clinical practice to treat rheumatoid arthritis and other autoimmune diseases, with significant beneficial effects but also high toxicity, necessitating rigorous quality evaluation and control. In current study, a rapid resolution liquid chromatography tandem electrospray ionization triple quadrupole mass spectrometry (RRLC–ESI–MS/MS) method was developed and validated for the quantitative analysis of 14 components of ten batches of TGTs produced by different manufacturers, including four diterpenoids, three triterpenoids, and seven sesquiterpene alkaloids. Meanwhile, the NO inhibition effects of these TGTs were evaluated in LPS-induced RAW264.7 cells for their downstream anti-inflammatory activities, as well as their cytotoxicity. The results indicate that the TGTs from different manufacturers showed poor quality consistency, as evidenced by large variations in chemical profiles and biological effects, which may increase the risks associated with clinical use. To improve the quality status of TGTs, it is crucial to identify indicator components whose characterization can accurately reflect the efficacy and toxicity of TGTs from which they were derived. Our study reveals that triptolide, triptoquinone B, celastrol, and demethylzelaysteral considerably contributed to the anti-inflammatory activity and/or cytotoxicity of TGTs, implying that they should be further investigated as candidate indicator components for TGT quality control.