Erythrityl Tetranitrate

Iron single‐atom nanozymes represent a promising artificial enzyme with superior activity owing to uniform active sites that can precisely mimic active center of nature enzymes. However, current synthetic strategies are hard to guarantee each active site at single‐atom state. In this work, an erythrocyte‐templated strategy by utilizing intrinsic hemin active center of hemoglobin as sing‐atom source for nanozyme formation is developed. By combining cell fixation, porous salinization, and high‐temperature carbonization, erythrocytes are successfully served as uniform templates to synthesize nanozymes with fully single‐atom FeN4 active sites which derived from hemin of hemoglobin, resulting in an enhanced peroxidase (POD)‐like activity. Interestingly, the catalytic activity of erythrocyte‐templated nanozyme (ETN) shows dependence on animal species, among which murine ETN performed superior catalytic efficiency. In addition, the as‐prepared ETNs display a honeycomb‐like network structure, serving as a sponge to accelerate hemostasis based on the interactions with prothrombin and fibrinogen. These features enable ETN to effectively kill methicillin‐resistant Staphylococcus aureus (MRSA) by combining POD‐like catalysis with near‐infrared (NIR) induced photothermal effect, and subsequently suitable to promote wound healing. This study provides a proof‐of‐concept for facile fabrication of multifunctional nanozymes with uniform single‐atom active sites by utilizing intrinsic iron structure characteristics of biogenic source like erythrocytes.

Nitrogen fertilization can mitigate the negative effects of high temperatures on rice. In this study, we simulated dynamic field temperature increases using a free-air temperature enhancement system. Changes in the physicochemical properties of starch were investigated under increasing nitrogen fertilization during the grain-filling stage. We observed that the application of nitrogen at elevated temperatures (ETN) did not change the chain length distribution compared with elevated temperatures (ET) alone; however, it did significantly increase the heights of the first and second amylose peaks. Specifically, ETN significantly decreased the height of fifth amylopectin and relative crystallinity, and the changes it introduced in the physicochemical properties of starch were greater than those of ET. Overall, these changes in starch properties may be associated with the ability of nitrogen to facilitate the maintenance of rice quality at high temperatures.