Search

To assess the viability and effectiveness of bioretention cell in enhancing rainwater resource utilization within sponge cities, this study employs field monitoring, laboratory testing, and statistical analysis to evaluate the water purification capabilities of bioretention cell. Findings indicate a marked purification impact on surface runoff, with removal efficiencies of 59.81% for suspended solids (SS), 39.01% for chemical oxygen demand (COD), 37.53% for ammonia nitrogen (NH3-N), and 30.49% for total phosphorus (TP). The treated water largely complies with rainwater reuse guidelines and tertiary sewage discharge standards. Notably, while previous research in China has emphasized water volume control in sponge city infrastructures, less attention has been given to the qualitative aspects and field-based evaluations. This research not only fills that gap but also offers valuable insights and practical implications for bioretention cell integration into sponge city development. Moreover, the methodology and outcomes of this study serve as a benchmark for future sponge city project assessments, offering guidance to relevant authorities. HIGHLIGHTS Explored the purification of bioretention cells on rainwater.; Under the same conditions, the bioretention cell has the best purification effect on suspended solids.; The bioretention cell's effluent quality complies with standards for urban recycled water, wastewater discharge, and sponge city assessments.;

In the present study, multiscale finite element (FE) models of half-through steel basket-handle arch bridges were established. The eigenvalue analyses were conducted to explore the dynamic characteristics of the arch bridges based on the FE models. In addition, a parametric analysis was carried out to investigate the impact of the inclination angle of the arch rib (0°, 4°, and 7°) on the longitudinal and transverse seismic performances of arch bridges. The results show that with the increase in inclination angle, the out-of-plane stiffness of half-through steel basket-handle arch bridges increases, resulting in the natural period of the structure becoming shorter from 3.09 s to 2.93 s. Adjusting the inclination angle appropriately has a beneficial impact on the overall seismic performance of the structures, affecting both displacement and internal forces, in which the most significant improvements include a 42.8% decrease in displacement and a 62.6% reduction in internal forces. Adjusting the inclination angle can cause the arch springing and transverse brace to undergo larger plastic deformation. It is advisable to judiciously enlarge the sectional dimensions and enhance the material strength of both the arch springing and the transverse bracing in seismic designs.

ABSTRACT LysR-type transcriptional regulators (LTTRs), which function in diverse biological processes in prokaryotes, are composed of a conserved structure with an N-terminal DNA-binding domain (DBD) and a C-terminal signal-sensing regulatory domain (RD). LTTRs that sense and respond to the same signal are often functionally exchangeable in bacterial species across wide phyla, but this phenomenon has not been demonstrated for the H2O2-sensing and -responding OxyRs. Here, we systematically examined the biochemical and structural determinants differentiating activator-only OxyRs from dual-activity ones by comparing OxyRs from two Gammaproteobacteria, Escherichia coli and Shewanella oneidensis. Our data show that EcOxyR could function as neither an activator nor a repressor in S. oneidensis. Using SoOxyR-based OxyR chimeras and mutants, we demonstrated that residues 283 to 289, which form the first half of the last C-terminal α-helix (α10), are critical for the proper function of SoOxyR and cannot be replaced with the EcOxyR counterpart. Crystal structural analysis reveals that α10 is important for the oligomerization of SoOxyR, which, unlike EcOxyR, forms several high-order oligomers upon DNA binding. As the mechanisms of OxyR oligomerization vary substantially among bacterial species, our findings underscore the importance of subtle structural features in determining regulatory activities of structurally similar proteins descending from a common ancestor. IMPORTANCE Evolution may drive homologous proteins to be functionally nonexchangeable in different organisms. However, much is unknown about the mechanisms underlying this phenomenon beyond amino acid substitutions. Here, we systematically examined the biochemical and structural determinants differentiating functionally nonexchangeable OxyRs, H2O2-responding transcriptional regulators from two Gammaproteobacteria, Escherichia coli and Shewanella oneidensis. Using SoOxyR-based OxyR chimeras and mutants, we demonstrated that residues 283 to 289, which form the first half of the last C-terminal α-helix (α10), are critical for the proper function of SoOxyR and cannot be replaced with the EcOxyR counterpart. Crystal structural analysis reveals that this last helix is critical for formation of high-order oligomers upon DNA binding, a phenomenon not observed with EcOxyR. Our findings provide a new dimension to differences in sequence and structural features among bacterial species in determining regulatory activities of homologous regulators.