SUSTAIN drilling at Surtsey volcano, Iceland, tracks hydrothermal and microbiological interactions in basalt 50 years after eruption

The 2017 Surtsey Underwater volcanic System for Thermophiles, Alteration processes and INnovative concretes (SUSTAIN) drilling project at Surtsey volcano, sponsored in part by the International Continental Scientific Drilling Program (ICDP), provides precise observations of the hydrothermal, geochemical, geomagnetic, and microbiological changes that have occurred in basaltic tephra and minor intrusions since explosive and effusive eruptions produced the oceanic island in 1963–1967. Two vertically cored boreholes, to 152 and 192 m below the surface, were drilled using filtered, UV-sterilized seawater circulating fluid to minimize microbial contamination. These cores parallel a 181 m core drilled in 1979. Introductory investigations indicate changes in material properties and whole-rock compositions over the past 38 years. A Surtsey subsurface observatory installed to 181 m in one vertical borehole holds incubation experiments that monitor in situ mineralogical and microbial alteration processes at 25–124 ∘C. A third cored borehole, inclined 55∘ in a 264∘ azimuthal direction to 354 m measured depth, provides further insights into eruption processes, including the presence of a diatreme that extends at least 100 m into the seafloor beneath the Surtur crater. The SUSTAIN project provides the first time-lapse drilling record into a very young oceanic basaltic volcano over a range of temperatures, 25–141 ∘C from 1979 to 2017, and subaerial and submarine hydrothermal fluid compositions. Rigorous procedures undertaken during the drilling operation protected the sensitive environment of the Surtsey Natural Preserve

Duplicated Sequence Motif in the Long Terminal Repeat of Maedi-Visna Virus Extends Cell Tropism and Is Associated with Neurovirulence

Maedi-visna virus (MVV) is a lentivirus of sheep causing chronic inflammatory disease of the lungs (maedi) and the nervous system (visna). We have previously shown that a duplicated sequence in the long terminal repeat (LTR) of MVV is a determinant of cell tropism. Here, we demonstrate that deletion of a CAAAT sequence from either one of the repeats resulted in poor virus growth in sheep choroid plexus cells. A duplication in the LTR encompassing the CAAAT sequence was found in four neurological field cases that were sequenced, but no duplication was present in the LTRs from seven maedi cases; one maedi isolate was mixed. These results indicate that the duplication in the LTR is associated with neurovirulence

Multicenter study on postcardiotomy venoarterial extracorporeal membrane oxygenation

Abstract Objectives: The aim of this study was to identify the risk factors associated with early mortality after postcardiotomy venoarterial extracorporeal membrane oxygenation. Methods: This is an analysis of the postcardiotomy extracorporeal membrane oxygenation registry, a retrospective multicenter cohort study including 781 patients aged more than 18 years who required venoarterial extracorporeal membrane oxygenation for cardiopulmonary failure after cardiac surgery from 2010 to 2018 at 19 cardiac surgery centers. Results: After a mean venoarterial extracorporeal membrane oxygenation therapy of 6.9 ± 6.2 days, hospital and 1–year mortality were 64.4% and 67.2%, respectively. Hospital mortality after venoarterial extracorporeal membrane oxygenation therapy for more than 7 days was 60.5% (P = .105). Centers that had treated more than 50 patients with postcardiotomy venoarterial extracorporeal membrane oxygenation had a significantly lower hospital mortality than lower–volume centers (60.7% vs 70.7%, adjusted odds ratio, 0.58; 95% confidence interval, 0.41–0.82). The postcardiotomy extracorporeal membrane oxygenation score was derived by assigning a weighted integer to each independent pre–venoarterial extracorporeal membrane oxygenation predictors of hospital mortality as follows: female gender (1 point), advanced age (60–69 years, 2 points; ≥70 years, 4 points), prior cardiac surgery (1 point), arterial lactate 6.0 mmol/L or greater before venoarterial extracorporeal membrane oxygenation (2 points), aortic arch surgery (4 points), and preoperative stroke/unconsciousness (5 points). The hospital mortality rates according to the postcardiotomy extracorporeal membrane oxygenation score was 0 point, 45.6%; 1 point, 40.5%; 2 points, 51.1%; 3 points, 57.8%; 4 points, 70.7%; 5 points, 68.3%; 6 points, 77.5%; and 7 points or more, 89.7% (P < .0001). Conclusions: Age, female gender, prior cardiac surgery, preoperative acute neurologic events, aortic arch surgery, and increased arterial lactate were associated with increased risk of early mortality after postcardiotomy venoarterial extracorporeal membrane oxygenation. Center experience with postcardiotomy venoarterial extracorporeal membrane oxygenation may contribute to improved results.Collaborators of the PC-ECMO Study Group: Kristiina Pälve, MD, PhD, Vesa Anttila, MD, PhD, MD, Thomas Fux, MD, PhD, Gilles Amr, MD, Nikolaos Kalampokas, MD, Artur Lichtenberg, MD, Anders Jeppsson, MD, PhD, Marco Gabrielli, MD, Daniel Reichart, MD, Sidney Chocron, MD, PhD, Mariafrancesca Fiorentino, MD, Ugolino Livi, MD, Ivan Netuka, MD, Dieter De Keyzer, MD, Krister Mogianos, MD, Zein El Dean, MRCS, LLM, Angelo M. Dell’Aquila, MD, Nicla Settembre, MD, PhD, and Stefano Rosato, MSc

Robust Estimation of Diffusion-Optimized Ensembles for Enhanced Sampling

The multicanonical, or flat-histogram, method is a common technique to improve the sampling efficiency of molecular simulations. The idea is that free-energy barriers in a simulation can be removed by simulating from a distribution where all values of a reaction coordinate are equally likely, and subsequently reweight the obtained statistics to recover the Boltzmann distribution at the temperature of interest. While this method has been successful in practice, the choice of a flat distribution is not necessarily optimal. Recently, it was proposed that additional performance gains could be obtained by taking the position-dependent diffusion coefficient into account, thus placing greater emphasis on regions diffusing slowly. Although some promising examples of applications of this approach exist, the practical usefulness of the method has been hindered by the difficulty in obtaining sufficiently accurate estimates of the diffusion coefficient. Here, we present a simple, yet robust solution to this problem. Compared to current state-of-the-art procedures, the new estimation method requires an order of magnitude fewer data to obtain reliable estimates, thus broadening the potential scope in which this technique can be applied in practice