This paper summarizes the biostratigraphy and magnetostratigraphy of the 11 sites drilled on the Kerguelen Plateau and in Prydz Bay, Antarctica, during ODP Leg 119. Excellent magnetobiochronologic reference sections were obtained at deep-water Sites 745 and 746 (0-10 Ma) and at intermediate depth Site 744 (0-39 Ma) on the southern Kerguelen Plateau. Site 738, an intermediate depth companion site for Site 744, contains a nearly complete lowermost Oligocene to Turonian carbonate section including a continuous sequence across the Cretaceous/Tertiary boundary. Northern Kerguelen Sites 736 and 737 (ca. 600 m water depth) constitute a composite middle Eocene to Quaternary reference section near the present-day Antarctic Polar Front. Biostratigraphic control is limited in Prydz Bay Sites 739-743. Glacial sequences cored on the continental shelf at Sites 739 and 742 appear to form a composite record, possibly from the uppermost middle Eocene to the Quaternary; the entire upper Oligocene and most of the Miocene, however, are removed at an unconformity. Preglacial sediments at Site 741 contain Early Cretaceous pollen and spores, but the red beds cored at Site 740 are unfossiliferous. Poorly-fossiliferous glacial sediments of probable Quaternary age were sampled on the upper slope at Site 743. A magnetobiochronologic time scale is presented for the Late Cretaceous and Cenozoic of the Southern Ocean based on previous studies and the results of Leg 119 studies.

Solar distillation through photothermal evaporators has approached solar light energy (E1) limit under no solar concentration but still suffers from modest vapor and clean water production. Herein, a nature-inspired low-tortuosity three-dimensional (3D) evaporator is demonstrated to significantly improve water production. The solar evaporator, prepared from polypyrrole-modified maize straw (PMS), had upright vascular structures enabling high water lifting and horizontal microgaps facilitating broad water distribution to the out-surface. Consequently, this novel PMS evaporator dramatically enhanced the utilization of the solar heat energy stored in the environment (E2) for promoting evaporation. The maximum vapor generation rate of a single PMS respectively increases 2.5 and 6 times compared with the conventional 3D evaporators and the planar evaporators of an identical occupied area. Consequently, a scaled-up PMS array achieved a state-of-the-art vapor generation rate of 3.0 L m–2 h–1 (LMH) under a simulated condition and a record-high clean water production of 2.2 LMH for actual seawater desalination under natural conditions (1 sun intensity). This breakthrough reveals great potentials for cost-effective freshwater production as well as the rational design of high-performance photothermal evaporators for solar distillation.

No abstract

Uranium contamination of surface environments is a problem associated with both U-ore extraction/processing and situations in which groundwater comes into contact with geological formations high in uranium. Apart from the environmental concerns about U contamination, its accumulation and isotope composition have been used in marine sediments as a paleoproxy of the Earth's oxygenation history. Understanding U isotope geochemistry is then essential either to develop sustainable remediation procedures as well as for use in paleotracer applications. We report on parameters controlling U immobilization and U isotope fractionation by adsorption onto Mn/Fe oxides, precipitation with phosphate, and biotic reduction. The light U isotope (U) is preferentially adsorbed on Mn/Fe oxides in an oxic system. When adsorbed onto Mn/Fe oxides, dissolved organic carbon and carbonate are the most efficient ligands limiting U binding resulting in slight differences in U isotope composition (δU = 0.22 ± 0.06‰) compared to the DOC/DIC-free configuration (δU = 0.39 ± 0.04‰). Uranium precipitation with phosphate does not induce isotope fractionation. In contrast, during U biotic reduction, the heavy U isotope (U) is accumulated in reduced species (δU up to -1‰). The different trends of U isotope fractionation in oxic and anoxic environments makes its isotope composition a useful tracer for both environmental and paleogeochemical applications.

No abstract

No abstract

No abstract

In this study, the aqueous and ethanolic extracts (leaves, stems and fruits) from Morus alba L., a traditional Chinese medicine, were evaluated for their antioxidant and antimicrobial properties. Ethanolic extracts showed higher contents of both total phenolics and flavonoids than aqueous extracts. The total phenolic content was in the order of: leaf extracts > fruit extracts > stem extracts, whereas the total flavonoids was: leaf extracts > stem extracts > fruit extracts. Using DPPH assays, the concentrations providing 50% inhibition (IC(50)) values of aqueous extracts from leaves, stems and fruits were 7.11 ± 1.45 mg/ml, 86.78 ± 3.21 mg/ml and 14.38 ± 2.83 mg/ml, respectively, whereas the IC(50) values of ethanolic extracts were 3.11 ± 0.86 mg/ml, 14.62 ± 2.45 mg/ml and 12.42 ± 2.76 mg/ml, respectively. In sum, the antioxidant activities of ethanolic extracts from M. alba L. were stronger than the aqueous extracts, and in the order of: leaf extracts > fruit extracts > stem extracts. The ethanolic extracts exhibited moderate antimicrobial activities, whereas the aqueous extracts showed poor antimicrobial properties in our test system. This study validated the medicinal potential of M. alba L.