Understanding tissue biodistribution and clearance of zinc oxide nanoparticles (ZnO-NPs) is necessary for its risk assessment. Both fed and intraperitoneally injected ZnO-NPs (2.5 g/kg) were absorbed into circulation (within 30 min post-dosing), then biodistributed to the liver, spleen, and kidney. Intraperitoneally injected ZnO-NPs remained in serum for 72 h and could more effectively spread to the heart, lung, and testes, whereas the clearance for fed ZnO-NPs in serum began 6 h after oral administration. Compared with zinc oxide microparticles (ZnO-MPs), ZnO-NPs exhibited much higher absorptivity and tissue biodistribution in fed treatment. A greater fraction of fed ZnO-NPs localised in the liver resulted in transient histopathological lesions. However, superoxide generation and cytotoxicity were showed in vitro treatment with ZnO-NPs (above 20 μg/mL). Considering both in vitro and in vivo data, the ZnO-NPs induced acute liver toxicity which was in compliance with its absorption, biodistribution, and clearance.

The Intertropical Convergence Zone (ITCZ) encompasses the heaviest rain belt on the Earth. Few direct long-term records, especially in the Pacific, limit our understanding of long-term natural variability for predicting future ITCZ migration. Here we present a tropical precipitation record from the Southern Hemisphere covering the past 282,000 years, inferred from a marine sedimentary sequence collected off the eastern coast of Papua New Guinea. Unlike the precession paradigm expressed in its East Asian counterpart, our record shows that the western Pacific ITCZ migration was influenced by combined precession and obliquity changes. The obliquity forcing could be primarily delivered by a cross-hemispherical thermal/pressure contrast, resulting from the asymmetric continental configuration between Asia and Australia in a coupled East Asian–Australian circulation system. Our finding suggests that the obliquity forcing may play a more important role in global hydroclimate cycles than previously thought.

Over at least the past millennium, the Mentawai segment of the Sunda megathrust has failed in sequences of closely timed events rather than in single end‐to‐end ruptures—each the culmination of an earthquake “supercycle.” Here we synthesize the sixteenth‐ and seventeenth‐century coral microatoll records into a chronology of interseismic and coseismic vertical deformation. We identify at least five discrete uplift events in about 1597, 1613, 1631, 1658, and 1703 that likely correspond to large megathrust ruptures. This sequence contrasts with the following supercycle culmination, which involved only two large ruptures in 1797 and 1833. Fault slip modeling suggests that together the five cascading ruptures involved failure of the entire Mentawai segment. Interseismic deformation rates also changed after the onset of the rupture sequence, as they did after the 1797 earthquake. We model this change as an altered distribution of fault coupling, presumably triggered by the ~1597 rupture. We also analyze the far less continuous microatoll record between A.D. 1 and 1500. While we cannot confidently delineate the extent of any megathrust rupture during that period, all evidence suggests that individual major ruptures involve only part of the Mentawai segment, often overlap below the central Mentawai Islands, often trigger coupling changes, and occur in clusters that cumulatively cover the entire Mentawai segment at the culmination of each supercycle. It is clear that each Mentawai rupture sequence evolves uniquely in terms of the order and grouping of asperities that rupture, suggesting heterogeneities in fault frictional properties at the ~100 km scale.