The recent development of nanozymes for targeting antibacterial, anticancer and antioxidant applications are summarized.

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Barbecue smoke, car exhaust, cigarette smoke, and other waste gases contain toxic reactive oxygen species (ROS) and polycyclic aromatic hydrocarbons (PAHs). Herein, CeO 2 -based porous carbonaceous frameworks (CeO 2 PCFs) were explored as antioxidant nanozymes to scavenge ROS and absorb benzo[a]pyrene (B[a]P). Using cerium-based frameworks as the precursors, CeO 2 PCFs were constructed by high-temperature calcination. Due to excellent superoxide dismutase-like and catalase-like activity, CeO 2 PCFs could effectively eliminate superoxide radical, hydroxyl radical, and hydrogen peroxide. The 2,2′-azino-bis (3ethylbenzthiazoline-6-sulfonic acid) free radical scavenging assay had substantiated free radical scavenging ability of CeO 2 PCFs. In addition, with a large surface area and porous structure, CeO 2 PCFs could adsorb B[a]P efficiently. The designed CeO 2 PCFs may provide a new opportunity as scavengers of ROS and absorbents of PAHs in some harmful gases.

Analyzing urban-rural spatial structures and changes are of great significance for under-standing the urban-rural relationship evolution. While previous studies mostly focused on the urban internal spatial structure evolution, less from the regional scale to explore the urban and rural evolution. Here, taking Dezhou city, a rapidly urbanization city in China as a case study, we employed the local contour tree method and nighttime light data to map urban and active rural regions’ range during 2012-2020, and further explored the respective development processes of them. This study found that different from rural regions, internal structures of urban regions are more complex, and there are often multiple hot spots inside them. The urban-rural regions’ area had increased significantly by 39.3% during 2012-2020 (p<0.05). The urban and rural region rankings of the identified counties are basically consistent with the urban and rural population rankings. Particularly, different from perspectives of earlier land use (i.e., built-up land or impervious surface), this study identified urban and active rural regions in view of the scope of active human activities. This study therefore found populations were greatly responsible for affecting changes of urban and active rural region structures. These findings could be helpful for understanding urban-rural dynamics.