Recent events, including COVID-19, extreme floods, and explosion accidents, commonly induced localized closures and disruptions of urban road networks (URNs), resulting in significant impacts on human mobility and socio-economic activities. Existing studies on URN resilience to those events mainly took few cases for empirical studies, limiting our understanding on the URN resilience patterns across different cities. By conducting a large-scale nationwide resilience analysis of URNs in 363 cities in mainland China, this study attempts to uncover the resilience patterns of URNs against the worst-case single (SLDs) and multiple localized disruptions (MLDs). Results show that the distance from the worst-case SLD to the city center would be less than 5 km in 62.3% cities, as opposed to more than 15 km in 14.3% cities. Moreover, the average road network resilience of cities in western China could be 7% and 13% smaller than that of the eastern cities under the worst-case SLDs and MLDs, respectively. This inequality in the worst-case resilience is partly attributable to variations in urban socio-economic, infrastructure-related, and topographic factors. These findings could inspire nationwide pre-disaster mitigation strategies to cope with localized disruptions and help transfer insights for mitigation strategies against disruptive events across cities.

OBJECTIVE: During physical transfection, an electrical field or mechanical force is used to induce cell transfection. We tested if the disruption of a dense actin layer underneath the membrane of a suspended cell enhances cell transfection.
RESULTS: A bubble generator was used to electromechanically stimulate suspended cells. To clarify the influence of the actin layer (the actin cortex) on cell transfection efficiency, we used an actin polymerization inhibitor (cytochalasin D) to disrupt the actin cortex before electromechanical stimulation. Without cytochalasin D treatment, signals from the overall actin cortex decreased after electromechanical stimulation. With cytochalasin D treatment, there was localized F-actin aggregation under static conditions. After electromechanical stimulation, there was a partial loss (localized disruption), but no overall disruption, of the actin cortex. With the pretreatment with cytochalasin D, the transfection efficiency of plasmids (4.7, 8.3, or 11 kbp) into NIH/3T3 or UMR-106 cells increased significantly after exposure to electromechanical stimulation.
CONCLUSIONS: Localized distribution of the actin cortex before exposure to electromechanical stimulation is crucial for inducing a partial loss of the cortex, which improves transfection efficiency and large plasmid delivery.