Astrobiology of life on Earth.

Astrobiology is mistakenly regarded by some as a field confined to studies of life beyond Earth. Here, we consider life on Earth through an astrobiological lens. Whereas classical studies of microbiology historically focused on various anthropocentric sub-fields (such as fermented foods or commensals and pathogens of crop plants, livestock and humans), addressing key biological questions via astrobiological approaches can further our understanding of all life on Earth. We highlight potential implications of this approach through the articles in this Environmental Microbiology special issue 'Ecophysiology of Extremophiles'. They report on the microbiology of places/processes including low-temperature environments and chemically diverse saline- and hypersaline habitats; aspects of sulphur metabolism in hypersaline lakes, dysoxic marine waters, and thermal acidic springs; biology of extremophile viruses; the survival of terrestrial extremophiles on the surface of Mars; biological soils crusts and rock-associated microbes of deserts; subsurface and deep biosphere, including a salticle formed within Triassic halite; and interactions of microbes with igneous and sedimentary rocks. These studies, some of which we highlight here, contribute to our understanding of the spatiotemporal reach of Earth'sfunctional biosphere, and the tenacity of terrestrial life. Their findings will help set the stage for future work focused on the constraints for life, and how organisms adapt and evolve to circumvent these constraints.

Transitory microbial habitat in the hyperarid Atacama Desert.

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today's extreme hyperaridity.

Authorship: from credit to accountability : Reflections from the Editors' Network.

The Editors' Network of the European Society of Cardiology (ESC) provides a dynamic forum for editorial discussions and endorses the recommendations of the International Committee of Medical Journal Editors (ICMJE) to improve the scientific quality of biomedical journals. Authorship confers credit and important academic rewards. Recently, however, the ICMJE emphasised that authorship also requires responsibility and accountability. These issues are now covered by the new (fourth) criterion for authorship. Authors should agree to be accountable and ensure that questions regarding the accuracy and integrity of the entire work will be appropriately addressed. This review discusses the implications of this paradigm shift on authorship requirements with the aim of increasing awareness of good scientific and editorial practices.

Corrosion of bare carbon steel as a passive sensor to assess moisture availability for biological activity in Atacama Desert soils.

Here we consider that the corrosion of polished bared metal coupons can be used as a passive sensor to detect or identify the lower limit of water availability suitable for biological activity in Atacama Desert soils or solid substrates. For this purpose, carbon steel coupons were deposited at selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, long rectangular shaped ones that were half-buried in a vertical position, and square shaped ones that were deposited on the soil surface. The morphological attributes observed by SEM inspection were found to correlate to the so-called humectation time which is determined from local meteorological parameters. The main finding was that the decreasing trend of atmospheric moisture along the transect was closely related to corrosion behaviour and water soil penetration. For instance, at the coastal site oxide phases formed on the coupon surface rapidly evolve into well-crystallized species, while at the driest inland site Lomas Bayas only amorphous oxide was observed on the coupons.

Assessment of different methods for shadow detection in high-resolution optical imagery and evaluation of shadow impact on calculation of NDVI, and evapotranspiration.

Significant efforts have been made recently in the application of high-resolution remote sensing imagery (i.e., sub-meter) captured by unmanned aerial vehicles (UAVs) for precision agricultural applications for high-value crops such as wine grapes. However, at such high resolution, shadows will appear in the optical imagery effectively reducing the reflectance and emission signal received by imaging sensors. To date, research that evaluates procedures to identify the occurrence of shadows in imagery produced by UAVs is limited. In this study, the performance of four different shadow detection methods used in satellite imagery was evaluated for high-resolution UAV imagery collected over a California vineyard during the Grape Remote sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX) field campaigns. The performance of the shadow detection methods was compared and impacts of shadowed areas on the normalized difference vegetation index (NDVI) and estimated evapotranspiration (ET) using the Two-Source Energy Balance (TSEB) model are presented. The results indicated that two of the shadow detection methods, the supervised classification and index-based methods, had better performance than two other methods. Furthermore, assessment of shadowed pixels in the vine canopy led to significant differences in the calculated NDVI and ET in areas affected by shadows in the high-resolution imagery. Shadows are shown to have the greatest impact on modeled soil heat flux, while net radiation and sensible heat flux are less affected. Shadows also have an impact on the modeled Bowen ratio (ratio of sensible to latent heat) which can be used as an indicator of vine stress level.

Xeropreservation of functionalized lipid biomarkers in hyperarid soils in the Atacama Desert.

Our understanding of long-term organic matter preservation comes mostly from studies in aquatic systems. In contrast, taphonomic processes in extremely dry environments are relatively understudied and are poorly understood. We investigated the accumulation and preservation of lipid biomarkers in hyperarid soils in the Yungay region of the Atacama Desert. Lipids from seven soil horizons in a 2.5 m vertical profile were extracted and analyzed using GC-MS and LC-MS. Diagnostic functionalized lipids and geolipids were detected and increased in abundance and diversity with depth. Deeper clay units contain fossil organic matter (radiocarbon dead) that has been protected from rainwater since the onset of hyperaridity. We show that these clay units contain lipids in an excellent state of structural preservation with functional groups and unsaturated bonds in carbon chains. This indicates that minimal degradation of lipids has occurred in these soils since the time of their deposition between >40,000 and 2 million years ago. The exceptional structural preservation of biomarkers is likely due to the long-term hyperaridity that has minimized microbial and enzymatic activity, a taphonomic process we term xeropreservation (i.e. preservation by drying). The degree of biomarker preservation allowed us to reconstruct major changes in ecology in the Yungay region that reflect a shift in hydrological regime from wet to dry since the early Quaternary. Our results suggest that hyperarid environments, which comprise 7.5% of the continental landmass, could represent a rich and relatively unexplored source of paleobiological information on Earth.

Data sharing: A new editorial initiative of the International Committee of Medical Journal Editors : Implications for the Editors' Network.

The International Committee of Medical Journal Editors (ICMJE) provides recommendations to improve the editorial standards and scientific quality of biomedical journals. These recommendations range from uniform technical requirements to more complex and elusive editorial issues including ethical aspects of the scientific process. Recently, registration of clinical trials, conflicts of interest disclosure, and new criteria for authorship - emphasising the importance of responsibility and accountability - have been proposed. Last year, a new editorial initiative to foster sharing of clinical trial data was launched. This review discusses this novel initiative with the aim of increasing awareness among readers, investigators, authors and editors belonging to the Editors' Network of the European Society of Cardiology.

Rationale and study design of the RESERVOIR trial: a randomized trial comparing reservoir-based polymer-free amphilimus-eluting stents versus everolimus-eluting stents with durable polymer in patients with diabetes mellitus.

BACKGROUND: Patients with diabetes mellitus (DM) remain at high risk for stent restenosis and adverse cardiovascular events in the drug-eluting stent era. The amphilimus-eluting stent (AES) is a third generation reservoir-based polymer-free drug-eluting stent that has shown promising preliminary results in patients with DM. It has been suggested that the formulation of the drug with fatty acids could not only modulate the drug release in a timely manner but also achieve convenient levels of drug concentration in diabetic cardiac cells. The aim of this trial is to assess the efficacy of the AES in patients with DM compared with the cobalt chromium everolimus-eluting stent with non-erodible polymer (EES). STUDY DESIGN: This is an investigator-initiated, multicenter, randomized clinical trial, performed in patients with DM. A total of 112 diabetic patients receiving glucose-lowering agents and requiring percutaneous revascularization of a de novo lesion will be randomized in a 1:1 fashion to receive AES or EES. The primary endpoint is the neointimal volume obstruction at 9 months, evaluated by optical coherence tomography. Secondary endpoints will include strut coverage, angiographic in-stent late loss and clinical endpoints such as target vessel revascularization or probable/definite stent thrombosis. This study completed the inclusion in October 2013. CONCLUSIONS: The RESERVOIR trial is an investigator-initiated trial that will evaluate whether the polymer-free AES is not inferior to the EES inhibiting the neointimal hyperplasia in patients with DM. These results are also expected to improve our knowledge of the neointimal healing process in this population (Clinicaltrials.gov number NCT01710748).

Stability against freezing of aqueous solutions on early Mars.

Many features of the Martian landscape are thought to have been formed by liquid water flow and water-related mineralogies on the surface of Mars are widespread and abundant. Several lines of evidence, however, suggest that Mars has been cold with mean global temperatures well below the freezing point of pure water. Martian climate modellers considering a combination of greenhouse gases at a range of partial pressures find it challenging to simulate global mean Martian surface temperatures above 273 K, and local thermal sources cannot account for the widespread distribution of hydrated and evaporitic minerals throughout the Martian landscape. Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox. Here we model the freezing and evaporation processes of Martian fluids with a composition resulting from the weathering of basalts, as reflected in the chemical compositions at Mars landing sites. Our results show that a significant fraction of weathering fluids loaded with Si, Fe, S, Mg, Ca, Cl, Na, K and Al remain in the liquid state at temperatures well below 273 K. We tested our model by analysing the mineralogies yielded by the evolution of the solutions: the resulting mineral assemblages are analogous to those actually identified on the Martian surface. This stability against freezing of Martian fluids can explain saline liquid water activity on the surface of Mars at mean global temperatures well below 273 K.

Neoatherosclerosis causing edge in-stent restenosis: optical coherence tomography findings.

A patient presenting with 'edge' in-stent restenosis 12 years after the implantation of a bare-metal stent in the mid-left anterior descending coronary artery is described. Optical coherence tomography disclosed the presence of ruptured neoatherosclerosis at the stent edge. The value of this imaging technique to unravel this unique underlying anatomic substrate is discussed. The therapy of choice for patients presenting with edge in-stent restenosis (ISR) is reviewed.

Mitochondria and the evolutionary roots of cancer.

Cancer disease is inherent to, and widespread among, metazoans. Yet, some of the hallmarks of cancer such as uncontrolled cell proliferation, lack of apoptosis, hypoxia, fermentative metabolism and free cell motility (metastasis) are akin to a prokaryotic lifestyle, suggesting a link between cancer disease and evolution. In this hypothesis paper, we propose that cancer cells represent a phenotypic reversion to the earliest stage of eukaryotic evolution. This reversion is triggered by the dysregulation of the mitochondria due to cumulative oxidative damage to mitochondrial and nuclear DNA. As a result, the phenotype of normal, differentiated cells gradually reverts to the phenotype of a facultative anaerobic, heterotrophic cell optimized for survival and proliferation in hypoxic environments. This phenotype matches the phenotype of the last eukaryotic common ancestor (LECA) that resulted from the endosymbiosis between an α-proteobacteria (which later became the mitochondria) and an archaebacteria. As such, the evolution of cancer within one individual can be viewed as a recapitulation of the evolution of the eukaryotic cell from fully differentiated cells to LECA. This evolutionary model of cancer is compatible with the current understanding of the disease, and explains the evolutionary basis for most of the hallmarks of cancer, as well as the link between the disease and aging. It could also open new avenues for treatment directed at reestablishing the synergy between the mitochondria and the cancerous cell.

Noachian and more recent phyllosilicates in impact craters on Mars.

Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.

Fostering diffusion of scientific contents of National Society Cardiovascular Journals:the new ESC search engine.

European Society of Cardiology (ESC) National Society Cardiovascular Journals (NSCJs) are high-quality biomedical journals focused on cardiovascular diseases. The Editors' Network of the ESC devises editorial initiatives aimed at improving the scientific quality and diffusion of NSCJ. In this article we will discuss on the importance of the Internet, electronic editions and open access strategies on scientific publishing. Finally, we will propose a new editorial initiative based on a novel electronic tool on the ESC web-page that may further help to increase the dissemination of contents and visibility of NSCJs.

Optical coherence tomography: from research to clinical application.

Optical coherence tomography (OCT) has revolutionized intracoronary imaging. The unprecedented spatial resolution of this technique (15 µm) provides unique insights on the microstructure of the coronary wall. Currently, OCT is increasingly used in clinical practice and also constitutes an emerging, highly robust, research tool. OCT allows detailed visualization of atherosclerotic plaques and provides reliable information on plaque composition (lipid, fibrous, calcified) although its limited tissue penetration usually precludes a comprehensive analysis of the total plaque burden. OCT is the only technique allowing accurate measurements of the thickness of the fibrous cap, a classical marker of plaque vulnerability, and readily detects thin-cap fibroatheromas. In patients with acute coronary syndromes, plaque ruptures, with associated red or white thrombus, are nicely identified. OCT is also valuable to assess the results of coronary interventions. Stent expansion can be easily ascertained. In addition, due to its 10-times higher resolution, OCT is superior to intravascular ultrasound in the detection of even minor degrees of strut malapposition, tissue prolapse, residual thrombus and edge dissections. Furthermore, during follow-up OCT has a unique value to unravel the presence of strut coverage and to detect mild amounts of neointimal proliferation that might represent a valid surrogate marker of drug-eluting stent safety and efficacy. Finally, OCT has been used to unravel the underlying mechanisms implicated in stent failure, namely in-stent restenosis and stent thrombosis. Therefore, OCT appears ideally suited to help to move forward our understanding on the pathophysiology of coronary artery disease and to improve clinical decision-making processes, meeting the ever-increasing demand on coronary artery anatomical information from clinicians and researchers.

Outcomes of a multidisciplinary mechanical circulatory support network in cardiogenic shock in a centre without heart transplant program: A successful interprofessional coordination model.

BACKGROUND AND OBJECTIVE: Cardiogenic shock (CS) mortality remains very high and mechanical circulatory support (MCS) may provide an effective alternative of treatment in selected patients. The aim of this study is to analyse the results of a multidisciplinary team care program (including anaesthesiologists, cardiologists, cardiothoracic surgeons, and intensivists) in CS patients who required MCS, in a tertiary centre without a heart transplant (HT) program. METHODS: Prospective observational study that sought to analyse the characteristics and survival to discharge predictors in a consecutive CS patients cohort treated with MCS. RESULTS: A total of 48 patients were included. Mean age was 61 ± 14 years. Before MCS, 45.8% of the patients presented with cardiac arrest. A 54.2% 30-day survival and 45.8% overall survival to discharge, was found. Age and vasoactive-inotropic score were independent predictors of mortality. CONCLUSIONS: A multidisciplinary team-care based MCS program in CS patients is feasible and may achieve favourable results in a centre without HT program.

Planetary Protection Assessment of Radioisotope Thermoelectric Generator (RTG)-Powered Landed Missions to Ocean Worlds: Application to Enceladus.

Landed missions to icy worlds with a subsurface liquid water ocean must meet planetary protection requirements and ensure a sufficiently small likelihood of any microorganism-bearing part of the landed element reaching the ocean. A higher bound on this likelihood is set by the potential for radioisotope thermoelectric generator (RTG) power sources, the hottest possible landed element, to melt through the ice shell and reach the ocean. In this study, we quantify this potential as a function of three key parameters: surface temperature, ice shell thickness (i.e., heat flux through the shell), and thickness of a porous (insulating) snow or regolith cover. Although the model we describe can be applied to any ocean world, we present results in the context of a landed mission concept to the south polar terrain of Saturn's moon Enceladus. In this particular context, we discuss planetary protection considerations for landing site selection. The likelihood of forward microbial contamination of Enceladus' ocean by an RTG-powered landed mission can be made sufficiently low to not undermine compliance with the planetary protection policy.

Science Objectives for Flagship-Class Mission Concepts for the Search for Evidence of Life at Enceladus.

Cassini revealed that Saturn's Moon Enceladus hosts a subsurface ocean that meets the accepted criteria for habitability with bio-essential elements and compounds, liquid water, and energy sources available in the environment. Whether these conditions are sufficiently abundant and collocated to support life remains unknown and cannot be determined from Cassini data. However, thanks to the plume of oceanic material emanating from Enceladus' south pole, a new mission to Enceladus could search for evidence of life without having to descend through kilometers of ice. In this article, we outline the science motivations for such a successor to Cassini, choosing the primary science goal to be determining whether Enceladus is inhabited and assuming a resource level equivalent to NASA's Flagship-class missions. We selected a set of potential biosignature measurements that are complementary and orthogonal to build a robust case for any life detection result. This result would be further informed by quantifications of the habitability of the environment through geochemical and geophysical investigations into the ocean and ice shell crust. This study demonstrates that Enceladus' plume offers an unparalleled opportunity for in situ exploration of an Ocean World and that the planetary science and astrobiology community is well equipped to take full advantage of it in the coming decades.

An evidence-based, multidisciplinary process for implementation of potentially better practices using a computerized medical record.

Although the Institute of Medicine of the USA has recommended elements for healthcare reform, the optimal means for incorporation of these elements into a healthcare setting remain undefined. A process for the implementation of potentially better practices is described that incorporates a computerized medical record into an evidence-based, multidisciplinary continuous quality improvement effort. Steps in the process include the following: fostering a culture change that incorporates key habits for improvement; identification of a potentially better practice; review of existing evidence and analysis of local experience; delineation of proposed outcomes and potential confounders; guideline formulation and implementation; monitoring of change effectiveness; ongoing multivariate data analyses; and policy formulation. Trainee education and family participation characterize all steps in the process. Consequently, the process incorporates all of the elements recommended by the Institute of Medicine of the USA for healthcare reform and may be adapted to any healthcare setting.