Effects of plant community structural characteristics on carbon sequestration in urban green spaces.

The structural characteristics of plant communities in urban green spaces have a significant impact on their carbon sequestration function. In this study, comprehensive data were collected from 106 plant communities (each 20 m × 20 m) in Zhengzhou Green Expo Park. We assessed aboveground and soil carbon storage, alongside maintenance carbon emissions, to quantify carbon dynamics. Our primary objective was to establish a statistical model that correlates the structural attributes of plant communities with their total annual carbon sequestration. This model aims to provide a quantitative framework for optimizing community structures to maximize carbon sequestration in urban green spaces. The results showed that density and coverage were significantly and positively correlated with aboveground and soil carbon stocks. Density and mean height were significantly and positively correlated with maintenance carbon emissions. Density played a key structural role in regulating the total carbon sequestration of the plant communities, being 27.24 times more effective than coverage. The total annual carbon sequestration of the plant community reached an optimal value of 327.67 kg CO2-eq/y-1 at a density and cover of 0.15 and 1, respectively. This study provides valuable data for increasing the carbon sink ability of urban green spaces through plant structure regulation and supporting low-carbon development strategies in urban management.

Precise Tuning of the D-Band Center of Dual-Atomic Enzymes for Catalytic Therapy.

Single-atom nanozyme-based catalytic therapy is of great interest in the field of tumor catalytic therapy; however, their development suffers from the low affinity of nanozymes to the substrates (H2O2 or O2), leading to deficient catalytic activity in the tumor microenvironment. Herein, we report a new strategy for precisely tuning the d-band center of dual-atomic sites to enhance the affinity of metal atomic sites and substrates on a class of edge-rich N-doped porous carbon dual-atomic sites Fe-Mn (Fe1Mn1-NCe) for greatly boosting multiple-enzyme-like catalytic activities. The as-made Fe1Mn1-NCe achieved a much higher catalytic efficiency (Kcat/Km = 4.01 × 105 S-1·M-1) than Fe1-NCe (Kcat/Km = 2.41 × 104 S-1·M-1) with an outstanding stability of over 90% activity retention after 1 year, which is the best among the reported dual-atom nanozymes. Theoretical calculations reveal that the synergetic effect of Mn upshifts the d-band center of Fe from -1.113 to -0.564 eV and enhances the adsorption capacity for the substrate, thus accelerating the dissociation of H2O2 and weakening the O-O bond on O2. We further demonstrated that the superior enzyme-like catalytic activity of Fe1Mn1-NCe combined with photothermal therapy could effectively inhibit tumor growth in vivo, with an inhibition rate of up to 95.74%, which is the highest value among the dual-atom artificial enzyme therapies reported so far.