Low-lying coastal areas are threatened worldwide by compound flooding effects, including sea-level rise (SLR), frequent tropical cyclones (TCs), and accelerated land subsidence (LS). Compound flooding results in a negative effect, creating challenges for decision-making and coastal management for sustainable urban development. To comprehend the precise consequences and the combined effect of LS and SLR on coastal cities and to inform management scientifically, we initially chose historical TCs (TC6311 and TC1415) that resulted in exceptionally high surges and significant losses as reference scenarios for simulating potential compound events. We then utilized a hydrodynamic model, which combines TCs, LS, and SLR, to simulate the combined impact of flood hazards. Our findings indicated that the highest subsidence rate exceeds −20 mm/yr, the cumulative subsidence reaches −119.09 mm and 68.44% of the land is experiencing subsidence from 2015 to 2021. When comparing flood scenarios with and without the influence of SLR, the most severely affected by LS is projected to become submerged and completely inundated by 2100. We found that the combined impact of SLR and LS significantly amplified flood inundation and SLR is the primary amplification factor of flooding, projected to account for 46.2% by 2100. The framework established in this study facilitates the quantitative assessment of the interactions among multi-driver factors of compound flooding, thereby serving as a supplementary and guiding tool for future risk management.

Extreme surges and rainfall represent major driving factors for compound flooding in estuary regions along the Chinese coast. The combined effect of extreme surges and rainfall (that is, compound floods) might lead to greater impacts than if the drivers occurred in isolation. Hence, understanding the frequency and severity of compound flooding is important for improving flood hazard assessment and compound flood resilience in coastal cities. In this study, we examined the dependence between extreme surges and corresponding rainfall events in 26 catchments along the Chinese coastline during typhoon and non-typhoon seasons using copula functions, to identify where the two drivers more often occur together and the implication for flood management in these locations. We found that the interaction between flood drivers is statistically significant in 10 catchments located around Hainan Island (south) and Shanghai, where surge peaks occur mainly during the typhoon season and around the Bohai Sea (north), where surge peaks occur mainly during the non-typhoon season. We further applied the copula-based framework to model the dependence between surge peaks and associated rainfall and estimate their joint and conditional probability in two specific locations—Hainan Island and the Bohai Sea, where the correlation between flood drivers is statistically significant. We observed that in Hainan Island where most of the surge peaks occur during the typhoon season, extreme rainfall events during the typhoon season are generally more intense compared to annual maxima rainfall. In contrast, around the Bohai Sea where surge peaks occur mainly outside the typhoon season, rainfall is less intense than annual maxima rainfall. These results show that the interaction between extreme surges and rainfall can provide valuable insight when designing coastal and urban infrastructure, especially in highly populated urban areas prone to both coastal and pluvial flooding, such as many Chinese coastal cities.

Reversible control over the functionality of biological systems via external triggers may be used in future medicine to reduce the need for invasive procedures. Additionally, externally regulated biomacromolecules are now considered as particularly attractive tools in nanoscience and the design of smart materials, due to their highly programmable nature and complex functionality. Incorporation of photoswitches into biomolecules, such as peptides, antibiotics, and nucleic acids, has generated exciting results in the past few years. Molecular motors offer the potential for new and more precise methods of photoregulation, due to their multistate switching cycle, unidirectionality of rotation, and helicity inversion during the rotational steps. Aided by computational studies, we designed and synthesized a photoswitchable DNA hairpin, in which a molecular motor serves as the bridgehead unit. After it was determined that motor function was not affected by the rigid arms of the linker, solid-phase synthesis was employed to incorporate the motor into an 8-base-pair self-complementary DNA strand. With the photoswitchable bridgehead in place, hairpin formation was unimpaired, while the motor part of this advanced biohybrid system retains excellent photochemical properties. Rotation of the motor generates large changes in structure, and as a consequence the duplex stability of the oligonucleotide could be regulated by UV light irradiation. Additionally, Molecular Dynamics computations were employed to rationalize the observed behavior of the motor-DNA hybrid. The results presented herein establish molecular motors as powerful multistate switches for application in biological environments.