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The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding that the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Magnesium-iron carbonates along grain boundaries indicate reactions with carbon dioxide-rich water under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks have been stored aboard Perseverance for potential return to Earth.

Accelerating microbial iron cycling is an innovative environmentally responsible strategy for mine remediation. In the present study, we extend the application of microbial iron cycling in environmental remediation, to include biocementation for the aggregation and stabilization of mine wastes. Microbial iron reduction was promoted monthly for 10 months in crushed canga (a by-product from iron ore mining, dominated by crystalline iron oxides) in 1 m 3 containers. Ferrous iron concentrations reached 445 ppm in treatments and diverse lineages of the candidate phyla radiation dominated pore waters, implicating them in fermentation and/or metal cycling in this system. After a 6-month evaporation period, iron-rich cements had formed between grains and 20-cm aggregates were recoverable from treatments throughout the 1-m depth profile, while material from untreated and water-only controls remained unconsolidated. Canga-adapted plants seeded into one of the treatments germinated and grew well. Therefore, application of this geobiotechnology offers promise for stabilization of mine wastes, as well as re-formation of surface crusts that underpin unique and threatened plant ecosystems in iron ore regions., (© 2020 The Authors. Microbial Biotechnology published by Society for Applied Microbiology and John Wiley & Sons Ltd.)

Novel biotechnologies are required to remediate iron ore mines and address the increasing number of tailings (mine waste) dam collapses worldwide. In this study, we aimed to accelerate iron reduction and oxidation to stabilize an artificial slope. An open-air bioreactor was inoculated with a mixed consortium of microorganisms capable of reducing iron. Fluid from the bioreactor was allowed to overflow onto the artificial slope. Carbon sources from the bioreactor fluid promoted the growth of a surface biofilm within the artificial slope, which naturally aggregated the crushed grains. The biofilms provided an organic framework for the nucleation of iron oxide minerals. Iron-rich biocements stabilized the artificial slope and were significantly more resistant to physical deformation compared with the control experiment. These biotechnologies highlight the potential to develop strategies for mine remediation and waste stabilization by accelerating the biogeochemical cycling of iron., Competing Interests: The authors declare no competing interest.

Robust methods for the characterisation of microbial biosignatures in geological matrices is critical for developing mineralogical biosignatures. Studying microbial fossils is fundamental for our understanding of the role microorganisms have played in elemental cycling in modern and ancient environments on Earth and potentially Mars. Here, we aim to understand what promotes the fossilisation of microorganisms after the initial stages of biomineralisation, committing bacteriomorphic structures to the geological record within iron-rich environments. Mineral encrusted cell envelope structures were routinely identified within a goethite-rich vein that cross-cut the saprolite (iron ore) of a weathered banded iron formation (BIF) system in the Quadrilátero Ferrífero, Brazil. The preservation of potential organic and mineralogical biosignatures associated with these fossils was characterised using the following high-resolution analytical techniques: scanning and transmission electron microscopy, focused ion beam scanning electron microscopy, nanoscale secondary ion mass spectrometry, synchrotron-based Fourier transform infrared spectroscopy and Raman spectroscopy. Electron microscopy demonstrated that mineral nucleation associated with a range of cell envelope structures typically followed the extant cell templates. These biologically-influenced iron-rich minerals are microcrystalline with minimal secondary growth. In contrast, intracellular mineralisation formed larger minerals that grew inward from the cell membrane to infill intracellular voids after cell death. A three dimensional reconstruction of encrusted cell envelopes in a fossilised biofilm suggests that microorganisms may be able to replicate, during the initial stages of mineralisation. Carbon and nitrogen signatures are preserved associated with the cell envelope structures; however, there were no conclusive mineralogical biosignatures associated with the mineralised cell envelopes highlighting the classical importance of morphology and elemental biosignatures in determining the biogenicity of bacteriomorphic structures.

Microbial biofilms growing in iron-rich seeps surrounding Lake Violão, Carajás, Brazil serve as a superb natural system to study the role of iron cycling in producing secondary iron cements. These seeps flow across iron duricrusts (referred to as canga in Brazil) into hydraulically restricted lakes in northern Brazil. Canga caps all of the iron ore deposits in Brazil, protecting them from being destroyed by erosion in this active weathering environment. Biofilm samples collected from these seeps demonstrated heightened biogeochemical iron cycling, contributing to the relatively rapid, seasonal formation of iron-rich cements. The seeps support iron-oxidising lineages including Sideroxydans, Gallionella, and an Azoarcus species revealed by 16S rRNA gene sequencing. In contrast, a low relative abundance of putative iron reducers; for example, Geobacter species (<5% of total sequences in any sample), corresponds to carbon limitation in this canga-associated ecosystem. This carbon limitation is likely to restrict anoxic niches to within biofilms. Examination of a canga rock sample collected from the edge of Lake Violão revealed an array of well- to poorly-preserved microbial fossils in secondary iron cements. These heterogeneous cements preserved bacterial cell envelopes and possibly extracellular polymeric substances within the microfossil iron-rich cements (termed biocements). Bacterial iron reduction initiates the sequence, and intuitively is the rate-limiting step in this broadly aerobic environment. The organic framework of the active- and paleo-biofilms appears to provide a scaffold for the formation of some cements within canga and likely expedites cement formation. The accelerated development of these resilient iron-rich biocements in the lake edge environment compared with surroundings duricrust-associated environments may provide insights into new approaches to remediate mined land, aiding to stabilise slopes, reduce erosion, restore functional hydrogeology and provide a substrate akin to natural canga for revegetation using endemic canga plant species, which have adapted to grow on iron-rich substrates., (Copyright © 2019. Published by Elsevier B.V.)

The surface crust that caps highly weathered banded iron formations (BIFs) supports a unique ecosystem that is a post-mining restoration priority in iron ore areas. Geochemical evidence indicates that biological processes drive the dissolution of iron oxide minerals and contribute to the ongoing evolution of this duricrust. However, limited information is available on present-day biogeochemical processes in these systems, particularly those that contribute to the precipitation of iron oxides and, thus, the cementation and stabilization of duricrusts. Freshly formed iron precipitates in water bodies perched on cangas in Karijini National Park, Western Australia, were sampled for microscopic and molecular analyses to understand currently active microbial contributions to iron precipitation in these areas. Microscopy revealed sheaths and stalks associated with iron-oxidizing bacteria. The iron-oxidizing lineages Sphaerotilus, Sideroxydans, and Pedomicrobium were identified in various samples and Leptothrix was common in four out of five samples. The iron-reducing bacteria Anaeromyxobacter dehalogens and Geobacter lovleyi were identified in the same four samples, with various heterotrophs and diverse cyanobacteria. Given this arid, deeply weathered environment, the driver of contemporary iron cycling in Karijini National Park appears to be iron-reducing bacteria, which may exist in anaerobic niches through associations with aerobic heterotrophs. Overall oxidizing conditions and Leptothrix iron-oxidizers contribute to net iron oxide precipitation in our sampes, rather than a closed biogeochemical cycle, which would result in net iron oxide dissolution as has been suggested for canga caves in Brazil. Enhancements in microbial iron oxide dissolution and subsequent reprecipitation have potential as a surface-crust-ecosystem remediation strategy at mine sites.

Context and Objectives: Glycoprotein inhibitors (abciximab, eptifibatide and tirofiban) are used in patients with unstable angina and non-ST-segment elevation myocardial infarction before percutaneous coronary intervention. Of these, tirofiban is the least effective. We hypothesized that the response to tirofiban might be associated with glycoprotein gene mutations., Design and Setting: Prospective study at Emergency Unit, Heart Institute (InCor), University of São Paulo., Method: Intrahospital evolution and platelet aggregation in response to tirofiban were analyzed in relation to four glycoprotein mutations in 50 patients indicated for percutaneous coronary intervention: 17 (34%) with unstable angina and 33 (66%) with non-ST-segment elevation myocardial infarction. Platelet aggregation was analyzed using the Born method. Blood samples were obtained before and one hour after tirofiban infusion. Glycoproteins Ia (807C/T ), Ib (Thr/Met) , IIb (Ile/Ser ) and IIIa (PIA ) were the mutations selected., Results: Hypertension, dyslipidemia, diabetes, smoking, previous coronary artery disease and stroke were similar between the groups. Mutant glycoprotein IIIa genotypes had lower platelet aggregation before tirofiban administration than that of the wild genotype (41.0% ± 22.1% versus 55.9% ± 20.8%; P = 0.035). Mutant glycoprotein IIIa genotypes correlated moderately with lower platelet inhibition (r = -0.31; P = 0.030). After tirofiban administration, platelet glycoprotein Ia, Ib, IIb and IIIa mutations did not influence the degree of inhibition of platelet aggregation or intrahospital mortality., Conclusions: Mutations of glycoproteins Ia, Ib, IIb and IIIa did not influence platelet aggregation in response to tirofiban in patients with unstable angina and non-ST-segment elevation myocardial infarction.

We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced (3)He, (21)Ne, and (36)Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.

Obesity is nowadays a serious worldwide public health problem. In order to give patients a better quality of live, there are now medical and surgical treatments that may be offered to those patients. Since 2005, the Hospital de Santarém has been doing bariatric surgery. From 77 procedures with laparoscopic adjustable gastric banding, there were three cases of migration. The authors propose a new procedure to deal with migrations, according to a classification for band migration, as an alternative to a removal by laparoscopy or laparotomy. Let loose technique is a procedure that can be used in patients with band migration beyond the angle of Treitz and without other associated complications. It is consist of removing the port under local anaesthesia, leaving the insufflations' tube, hospitalization for monitoring the patient and awaiting for the elimination of the band with faeces. It's less costly and with minimal risks for patient. The first results are satisfactory and encouraging.

Context: Postoperative venous thromboembolism is a frequent and severe disease that can lead to pulmonary embolism and post thrombotic syndrome. Although the venous thromboembolism prophylaxis is a proven strategy, an unsuitable indication is observed., Objective: To verify the indication of prophylaxis with heparin among patients of several surgical specialties of a School Tertiary Referral Hospital., Methods: It was accomplished a prospective study during 10 consecutive days in each month, from September to December of 2005, with 360 patients surgically treated in the specialties: General Surgery, Gynecology, Neurosurgery, Ortopedy and Traumatology, Urology and Angiology and Vascular Surgery, identifying risk factors for the development of venous thromboembolism (VTE) and the use of heparin prophylaxis according to the recommendations of the Brazilian Society of Angiology and Vascular Surgery., Results: Three hundred and fifty seven patients were evaluated, 24 (6,7%), 128 (35,9%) and 205 (57,4%) were included in low risk, medium risk and high risk for venous thromboembolism, respectively. One hundred and eighty four patients (51,5%) of the sample received prophylactic heparin. Heparin was used in 73,3% of the patients of General Surgery, 16,7% of Gynecology, 50,0% of Neurosurgery, 32,5% of Ortopedy and Traumatology, 37,3% of Urology and 97,7% of Angiology and Vascular Surgery. Only 38,3% of medium risk and 64,4% of high risk patients received prophylactic heparin. Heparin was suitably used in 77,6% of medium risk and in 63,6% of high risk patients. Thrombocytopenia, minor bleeding and major bleeding occurred in 3 (1,6%), 12 (6,5%) and 2 (1,1%) of the patients, respectively. Thromboembolic complications occurred in 6 (1,7%) cases., Conclusion: Although the indications of prophylactic heparin to venous thromboembolism are well known, we verify an incomplete adhesion of medical professionals, exposing patients to severe complications.

The subduction of oceanic plateaux, which contain extraordinarily thick basaltic crust and are the marine counterparts of continental flood-basalt provinces, is an important factor in many current models of plate motion and provides a potential mechanism for triggering plate reorganization. To evaluate such models, it is essential to decipher the history of the collision between the largest and thickest of the world's oceanic plateaux, the Ontong Java plateau, and the Australian plate, but this has been hindered by poor constraints for the arrival of the plateau at the Melanesian trench. Here we present (40)Ar-(39)Ar geochronological data on hotspot volcanoes in eastern Australian that reveal a strong link between collision of the Greenland-sized Ontong Java plateau with the Melanesian arc and motion of the Australian plate. The new ages define a short-lived period of reduced northward plate motion between 26 and 23 Myr ago, coincident with an eastward offset in the contemporaneous tracks of seamount chains in the Tasman Sea east of Australia. These features record a brief westward deflection of the Australian plate as the plateau entered and choked the Melanesian trench 26 Myr ago. From 23 Myr ago, Australia returned to a rapid northerly trajectory at roughly the same time that southwest-directed subduction began along the Trobriand trough. The timing and brevity of this collisional event correlate well with offsets in hotspot seamount tracks on the Pacific plate, including the archetypal Hawaiian chain, and thus provide strong evidence that immense oceanic plateaux, like the Ontong Java, can contribute to initiating rapid change in plate boundaries and motions on a global scale.

Supergene cryptomelane [K(1-2)(Mn(3+)Mn(4+))(8)O(16). chiH(2)O] samples from deeply weathered pegmatites in southeastern Brazil subjected to (40)K-(40)Ar and (40)Ar/(39)Ar analysis yielded (40)K-(40)Ar dates ranging from 10.1 +/- 0.5 to 5.6 +/- 0.2 Ma (million years ago). Laser-probe (40)Ar/(39)Ar step-heating of the two most disparate samples yielded plateau dates of 9.94 +/- 0.05 and 5.59 +/- 0.10 Ma, corresponding, within 2 sigma, to the (40)K-(40)Ar dates. The results imply that deep weathering profiles along the eastern Brazilian margin do not reflect present climatic conditions but are the result of a long-term process that was already advanced by the late Miocene. Weathering ages predate pulses of continental sedimentation along the eastern Brazilian margin and suggest that there was a time lag between weathering and erosion processes and sedimentation processes.