In this issue, J. Song et al. review oxidate-species-selective materials for diagnostic and therapeutic applications; S. Takeshita et al. summarize the chemistry of chitosan aerogels and three-dimensional pore control for tailored applications. The Minireviews deal with tailoring of optical properties of luminescent semiconducting nanocrystals through pressure (Z. Lin et al.) and small-molecule drug discovery for SARS-CoV-2 (H. Su et al.). In an Essay, A. Ghosh remembers Martin Gouterman as an exemplary gay scientist and mentor.

In the original research section, H. Li et al. present a self-assembled homochiral radical cage with paramagnetic properties. W. Shu et al. worked out direct access to primary amines from alkenes by selective metal-free hydroamination. W. Huang et al. describe frequency-upconverted stimulated emission by up to six-photon excitation from extended spiro-fused ladder-type oligo(p-phenylene)s (see picture). M. H. Stenzel et al. found that the protein corona leads to deformation of spherical micelles.

• Angewandte Chemie 18/2021: Exemplary Science,
  Angew. Chem. Int. Ed. 2020, 60 (18).