Bioorthogonal chemistry represents plenty of highly efficient and biocompatible reactions that proceed selectively and rapidly in biological situations without unexpected side reactions towards miscellaneous endogenous functional groups. Arise from the strict demands of physiological reactions, bioorthogonal chemical reactions are natively selective transformations that are rarely found in biological environments. Bioorthogonal chemistry has long been applied to tracking and real-time imaging of biomolecules in their physiological environments. Thereinto, tetrazine bioorthogonal reactions are particularly important and have increasing applications in these fields owing to their unique properties of easily controlled fluorescence or radiation off-on mechanism, which greatly facilitate the tracking of real signals without been disturbed by background. In this mini review, tetrazine bioorthogonal chemistry for in vivo imaging applications will be attentively appraised to raise some guidelines for prior tetrazine bioorthogonal chemical studies.

The hot deformation behaviour and processing maps of a typical Fe-Mn-Si-Cr steel for automotive body structures were investigated on a Gleeble3500 simulation tester by isothermal compression test in the temperature ranging of 950°C to 1150°C and a strain rate of 0.05-10 s −1 . The results show that dynamic recrystallisation softening mechanism is more evident at low strain rate, while dynamic recovery is more evident at high strain rate. The instability parameter ξ(1) values are negative and considered as unsafe deformation zones at low deformation temperature and high strain rates. The processing maps exhibit two safe domains for hot working: (a) 0.05-1 s −1 and 1080-1150°C, the power dissipation values of η increase with the increase of strain rate. (b) 0.05-1 s −1 and 950-1020°C, while strain is lower than 0.1, the values of η decrease with the increase of strain rate.