Light-toned salty soils and coexisting Si-rich species discovered by the Mars Exploration Rover Spirit in Columbia Hills

Light-toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences were grouped into four types on the basis of geomorphic settings. At three major exposures, the light-toned soils are hydrous and sulfate-rich. The spatial distributions of distinct types of salty soils vary substantially: with centimeter-scaled heterogeneities at Paso Robles, Dead Sea, Shredded, and Champagne-Penny, a well-mixed nature for light-toned soils occurring near and at the summit of Husband Hill, and relatively homogeneous distributions in the two layers at the Tyrone site. Aeolian, fumarolic, and hydrothermal fluid processes are suggested to be responsible for the deposition, transportation, and accumulation of these light-toned soils. In addition, a change in Pancam spectra of Tyrone yellowish soils was observed after being exposed to current Martian surface conditions for 175 sols. This change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface. Sirich nodules and soils were observed near the major exposures of S-rich soils. They possess a characteristic feature in Pancam visible near-infrared (Vis-NIR) spectra that may be diagnostic of hydrated species, and this spectral feature can be used to search for additional Si-rich species. The exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area. Hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the Neutron Spectrometer on Mars Odyssey.We thank NASA for funding the MER Athena Science team and the JPL engineering team for continuing to successfully operate the Mars Exploration rovers.https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2008JE00312

Proposition de création d'un étage würmien par la sous-commission de stratigraphie du Quaternaire européen de l'INQUA

During the meeting in the Würmian glaciation type area in South Germany and Austria (12-20/09/83), the sub-commission on European Quaternary Stratigraphy (S.E.Q.S.-INQUA) established a provisional proposal of a Würmian stage defined in the Samerberg type locality (Bayern) and subdivised into three parts (early-middle-late Würmian).Lors de sa réunion dans la région type de la glaciation würmienne en Bavière et en Autriche (12-20/09/83) la sous-commission de Stratigraphie du Quaternaire européen (INQUA) a proposé, à titre provisoire, la création d'un étage würmien défini dans la localité type de Samerberg (Bavière) et subdivisé en trois parties (Würmien ancien-moyen-récent).Chaline Jean, Jerz H. Proposition de création d'un étage würmien par la sous-commission de stratigraphie du Quaternaire européen de l'INQUA. In: Bulletin de l'Association française pour l'étude du quaternaire, vol. 20, n°4, 1983. pp. 149-152

Impact of an 0.2 km 3

The ~0.2 km3 Eibsee rock avalanche impacted Paleolake Eibsee and completely displaced its waters. This study anal- yses the lake impact and the consequences, and the catchment response to the landslide. A quasi‐3D seismic reflection survey, four sediment cores from modern Lake Eibsee, reaching far down into the rock avalanche mass, nine radiocarbon ages, and geomorphic analysis allow us to distinguish the main rock avalanche event from a secondary debris avalanche and debris flow. The highly flu- idized debris avalanche formed a megaturbidite and multiple swashes that are recorded in the lake sediments. The new calibrated age for the Eibsee rock avalanche of ~4080–3970 cal yr BP indicates a coincidence with rockslides in the Fernpass cluster and sub- aquatic landslides in Lake Piburg and Lake Plansee, and raises the possibility that a large regional earthquake triggered these events. We document a complex history of erosion and sedimentation in Lake Eibsee, and demonstrate how the catchment response and rebirth of the lake are revealed through the complementary application of geophysics, sedimentology, radiocarbon dating, and geo- morphology

Neolignans from leaves of Nectandra leucantha (Lauraceae) display in vitro antitrypanosomal activity via plasma membrane and mitochondrial damages

Chagas disease is a neglected tropical disease, caused by the protozoan parasite Trypanosoma cruzi, which affects more than eight million people in Tropical and Subtropical countries especially in Latin America. Current treatment is limited to nifurtimox and benznidazole, both with reduced effectiveness and high toxicity. In this work, the n-hexane extract from leaves of Nectandra leucantha (Lauraceae) displayed in vitro antitrypanosomal activity against T. cruzi. Using several chromatographic steps, four related neolignans were isolated and chemically characterized as dehydrodieugenol B (1), 1-(8-propenyl)-3-[3'-methoxy-1'-(8-propenyl)-phenoxy]-4,5dimethoxybenzene (2), 1-[(7S)-hydroxy-8-propenyl]-3-[3'-methoxy-1'-(8'-propenyl)-phenoxy]-4hydroxy-5-methoxybenzene (3), and 1-[(7S)-hydroxy-8-propenyl]-3-[3'-methoxy-1'-(8'-propenyl)-phenoxy]-4,5-dimethoxybenzene (4). These compounds were tested against intracellular amastigotes and extracellular trypomastigotes of T. cruzi and for mammalian cytotoxicity. Neolignan 4 showed the higher selectivity index (SI) against trypomastigotes (>5) and amastigotes (>13) of T. cruzi. The investigation of the mechanism of action demonstrated that neolignan 4 caused substantial alteration of the plasma membrane permeability, together with mitochondrial dysfunctions in trypomastigote forms. In silico studies of pharmacokinetics and toxicity (ADMET) properties predicted that all compounds were non-mutagenic, non-carcinogenic, non-genotoxic, weak hERG blockers, with acceptable volume of distribution (1.66-3.32 L/kg), and low rodent oral toxicity (LD50 810-e2200 mg/kg). Considering some clinical events of cerebral Chagas disease, the compounds also demonstrated favorable properties, such as blood-brain barrier penetration. Unfavorable properties were also predicted as high promiscuity for P450 isoforms, high plasma protein binding affinity (>91%), and moderate-to-low oral bioavailability. Finally, none of the isolated neolignans was predicted as interference compounds (PAINS). Considering the promising chemical and biological properties of the isolated neolignans, these compounds could be used as starting points to develop new lead compounds for Chagas disease. (C) 2017 Elsevier B.V. All rights reserved.Sao Paulo State Research FoundationCAPESCNPqFed Univ ABC, Ctr Nat Sci & Humanities, BR-09210180 Santo Andre, SP, BrazilTech Univ Carolo Wilhelmina Braunschweig, Inst Food Chem, D-38106 Braunschweig, GermanyAnhanguera Univ Sao Paulo, Biotechnol & Innovat Hlth Program, BR-05145200 Sao Paulo, BrazilUniv Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972270 Diadema, SP, BrazilAdolfo Lutz Inst, Ctr Parasitol & Mycol, BR-01246902 Sao Paulo, BrazilUniv Sao Paulo, Inst Med Trop Sao Paulo, BR-05403000 Sao Paulo, BrazilUniv Fed Goias, Fac Pharm, Lab Mol Modeling & Drug Design, LabMol, BR-74605170 Goiania, Go, BrazilUnievangel Univ Ctr, Postgrad Program Soc Technol & Environm, BR-75083515 Anapolis, Go, BrazilUniv Fed Sao Paulo, Inst Environm Chem & Pharmaceut Sci, BR-09972270 Diadema, SP, BrazilFAPESP: 2015/11936-2FAPESP: 2015/50075-2FAPESP: 2013/50228-8Web of Scienc