Carboxydotrophic growth of <i>Geobacter sulfurreducens</i>

This study shows that Geobacter sulfurreducensgrows on carbon monoxide (CO) as electron donor with fumarateas electron acceptor. Geobacter sulfurreducens wastolerant to high CO levels, with up to 150 kPa in the headspacetested. During growth, hydrogen was detected in very slightamounts (~5 Pa). In assays with cell-free extract of cellsgrown with CO and fumarate, production of hydrogen fromCO was not observed, and hydrogenase activity with benzylviologen as electron acceptor was very low. Taken together,this suggested that CO is not utilized via hydrogen as intermediate.In the presence of CO, reduction of NADP+ wasobserved at a rate comparable to CO oxidation coupled tofumarate reduction in vivo. The G. sulfurreducens genomecontains a single putative carbon monoxide dehydrogenaseencodinggene. The gene is part of a predicted operon alsocomprising a putative Fe–S cluster-binding subunit (CooF)and a FAD–NAD(P) oxidoreductase and is preceded by aputative CO-sensing transcription factor. This cluster may beinvolved in a novel pathway for CO oxidation, but furtherstudies are necessary to ascertain this. Similar gene clustersare present in several other species belonging to theDeltaproteobacteria and Firmicutes, for which CO utilizationis currently not known

Deep Conversion of Carbon Monoxide to Hydrogen and Formation of Acetate by the Anaerobic Thermophile Carboxydothermus hydrogenoformans

Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen gas suitable to fuel CO-sensitive fuel cells in a future hydrogen economy, provided sufficiently low levels of CO are reached. Here we study CO conversion and final CO levels in cultures of C. hydrogenoformans grown in batch cultures that were started with a 100% CO gas phase with and without removal of formed CO2. Final CO levels were 117 ppm without CO2 removal and below 2 ppm with CO2 removal. The Gibbs free energy change calculated with measured end concentrations and the detection of acetate suggest that C. hydrogenoformans shifted from a hydrogenogenic to an acetogenic metabolism

Carbon Monoxide as an Electron Donor for the Biological Reduction of Sulphate

Several strains of Gram-negative and Gram-positive sulphate-reducing bacteria (SRB) are able to use carbon monoxide (CO) as a carbon source and electron donor for biological sulphate reduction. These strains exhibit variable resistance to CO toxicity. The most resistant SRB can grow and use CO as an electron donor at concentrations up to 100%, whereas others are already severely inhibited at CO concentrations as low as 1-2%. Here, the utilization, inhibition characteristics, and enzymology of CO metabolism as well as the current state of genomics of CO-oxidizing SRB are reviewed. Carboxydotrophic sulphate-reducing bacteria can be applied for biological sulphate reduction with synthesis gas (a mixture of hydrogen and carbon monoxide) as an electron donor

Communicating disaster risk? An evaluation of the availability and quality of flood maps

One of the key priorities for disaster risk reduction is to ensure decision makers, stakeholders, and the public understand their exposure to disaster risk, so that they can take protective action. Flood maps are a potentially valuable tool for facilitating this understanding of flood risk, but previous research has found that they vary considerably in availability and quality. Using an evaluation framework comprising nine criteria grounded in existing scholarship, this study assessed the quality of flood maps available to the public in Canadian communities located in designated flood risk areas. It found that flood maps in most municipalities (62&thinsp;%) are low quality (meeting less than 50&thinsp;% of the criteria) and the highest score was 78&thinsp;% (seven of nine criteria met). The findings suggest that a more concerted effort to produce high-quality, publicly accessible flood maps is required to support Canada's international commitment to disaster risk reduction. Further questions surround possible weighting of quality assessment criteria, whether and how individuals seek out flood maps, and how flood risk information could be better communicated using modern technology.</p

Managing intoxications with nicotine-containing e-liquids

INTRODUCTION: Nicotine is an addictive and poisonous agent. The recent development of e-cigarettes has caused a new demand for highly concentrated nicotine-containing solutions. These concentrated nicotine solutions have also increased the risk of nicotine overdoses. AREAS COVERED: Essential factors for nicotine exposure are the concentration of the nicotine-containing e-liquid solution and its pharmacokinetics. Liquid nicotine refills contain nicotine in varying concentrations, which vary widely between and within products. The pharmacokinetics of nicotine are dependent on the route of administration, renal/hepatic clearance and urinary pH. The dose is another essential determinant of nicotine exposure. There is a considerable discrepancy between the generally accepted lethal dose and symptoms reported in case studies. Ingested doses correlate poorly to clinical symptoms. Symptoms of liquid nicotine toxicity vary from mild to severe between patients and are the result of overstimulation of nicotinic acetylcholine receptors, which may lead to fatal respiratory failure and cardiovascular collapse. EXPERT OPINION: The literature on nicotine-containing e-liquid intoxications originating from vaping device refills are mainly case reports. Based on these case reports, we propose a treatment plan which is primarily symptomatic. Research should focus on providing insight on its toxicity, based on oral and transdermal pharmacokinetics and on toxicodynamics

Outcome of Fenestrated Endovascular Aneurysm Repair in Octogenarians:A Retrospective Multicentre Analysis

Objective: An ageing population leads to more age related diseases, such as complex abdominal aortic aneurysms (AAA). Patients with complex AAAs and multiple comorbidities benefit from fenestrated endovascular aneurysm repair (FEVAR), but for the elderly this benefit is not completely clear. Methods: Between 2001 and 2016 all patients treated for complex AAA by FEVAR at two tertiary referral centres were screened for inclusion. Group 1 consisted of patients aged 80 years and older and group 2 of patients younger than 80 years of age. The groups were compared for peri-operative outcome, as well as patient and re-intervention free survival, and target vessel patency during follow up. Results: Group 1 consisted of 42 patients (median age 82 years; interquartile range [IQR] 81–83 years) and group 2 of 230 patients (median age 72 years; IQR 67–77 years). No differences were seen in pre-operative comorbidities, except for age and renal function. Renal function was 61.4 mL/min/1.73 m2 vs.74.5 mL/min/1.73 m2 (p < .01). No differences were seen between procedures, except for a slightly longer operation time in group two. Median follow up was 26 and 32 months, respectively. No difference was seen between the groups for estimated cumulative overall survival (p = .08) at one, three, and five years, being 95%, 58%, and 42% for group 1, and 88%, 75%, and 61% for group 2, respectively. There was no difference seen between groups for the estimated cumulative re-intervention free survival (p = .95) at one, three, and five years, being 84%, 84%, and 84% in group 1, respectively, and 88%, 84%, and 82% in group 2, respectively. Ultimately, no difference was seen between groups for the estimated cumulative target vessel patency (p = .56) at one, three, and five years, being 100%, 100%, and 90% for group 1, and 96%, 93% and 92% for group 2, respectively. Conclusion: Age itself is not a reason to withhold FEVAR in the elderly, and choice of treatment should be based on the patient's comorbidities and preferences

Facies model for a coarse-grained, tide-influenced delta : Gule Horn Formation (Early Jurassic), Jameson Land, Greenland

Acknowledgements: Funding for this project was provided from the Research Council of Norway through the Petromaks project 193059 and the FORCE Safari Project. Arild Andresen (University of Oslo) and Aka Lynge (POLOG) are thanked for logistical support, Björn Nyberg (Uni Research CIPR and University of Bergen) for assistance in the field, Arve Næss (Statoil) for providing data and assistance during the planning phase, Julien Vallet and Huges Fournier (Helimap Systems SA) for data acquisition. Riegl LMS GmbH is acknowledged for software support. We thank Brian Willis and an anonymous reviewer for their insightful and thorough reviews and Mariano Marzo for editorial comments.Peer reviewedPublisher PD

The mid-Cretaceous North Atlantic nutrient trap: Black shales and OAEs

Organic-rich sediments are the salient marine sedimentation product in the mid-Cretaceous of the ocean basins formed in the Mesozoic. Oceanic anoxic events (OAEs) are discrete and particularly organic-rich intervals within these mid-Cretaceous organic-rich sequences and are defined by pronounced carbon isotope excursions. Marine productivity during OAEs appears to have been enhanced by the increased availability of biolimiting nutrients in seawater due to hydrothermal alteration of submarine basalts in the Pacific and proto-Indian oceans. The exact mechanisms behind the deposition of organic-rich sediments in the mid-Cretaceous are still a matter of discussion, but a hypothesis which is often put forward is that their deposition was a consequence of the coupling of a particular paleogeography with changes in ocean circulation and nutrient supply. In this study, we used a global coupled climate model to investigate oceanic processes that affect the interbasinal exchange of nutrients as well as their spatial distribution and bioavailability. We conclude that the mid-Cretaceous North Atlantic was a nutrient trap as a consequence of an estuarine circulation with respect to the Pacific. Organic-rich sediments in the North Atlantic were deposited below regions of intense upwelling. We suggest that enhanced productivity during OAEs was a consequence of upwelling of Pacific-derived nutrient-rich seawater associated with submarine igneous events