Anzhe Wang,Ping Hu,Xinyuan Zhao,Zhizhi Wang,Cong Zhang,Yongzheng Wang
Although important, fracture strength in structural ceramics remains difficult to predict due to the inherent micropores, and there is a tremendous need for more precise modelling of pore-like flaw-strength relationship. In this study, classical crack problems were successfully transformed into pore-like flaw-strength models by adding a reasonable stress correction factor proposed by Gomez. Based on the accurate fracture toughness measurement and the precise laser introduction of flaws vs strength tests, the optimized Sato-Takahashi model, which is suitable for any cross-sectional shapes and sharpness flaws, was found to have fairly good prediction for fracture strength in five typical structural ceramics. The experimental error at very small-sized flaws was analyzed from the aspects of the critical flaw size and the inherent flaw size detected by nano-CT. Overall, the simple and user-friendly optimized Sato-Takahashi model could pave the way for quantitative assessments of reliability and failure causes for fine ceramics.
Directly observing intracellular nanostructure formation remains challenging. In this work, using a rationally designed small-molecule 4-nitrobenzyl carbamate–Cys(SEt)-Asp-Asp-Phe(iodine)–2-cyano-benzothiazole (NBC-Iod-CBT), we directly observed intracellular nanoparticle formation with nanocomputed tomography (nano-CT). In vitro, upon glutathione reduction and nitroreductase (NTR) cleavage, NBC-Iod-CBT undergoes a CBT-Cys click condensation reaction to self-assemble nanoparticles Iod-CBT-NPs with an average linear absorption coefficient (LAC) value of 0.182 ± 0.078 μm −1 to x-ray. Nano-CT imaging of the NBC-Iod-CBT–treated, NTR-overexpressing HeLa cells showed the existence of Iod-CBT-NPs in their cytoplasm with an average LAC value of 0.172 ± 0.032 μm −1 . We anticipate that our strategy could help people to deeply understand the formation mechanism of intracellular nanostructures in the near future.
危险品化学品经营许可证（带存储）