Colloidal mobilization of arsenic from mining-affected soils by surface runoff

Received 2 June 2015, Revised 2 September 2015, Accepted 24 September 2015, Available online 23 October 2015Scorodite-rich wastes left as a legacy of mining and smelting operations pose a threat to environmental health. Colloids formed by the weathering of processing wastes may control the release of arsenic (As) into surface waters. At a former mine site in Madrid (Spain), we investigated the mobilization of colloidal As by surface runoff from weathered processing wastes and from sediments in the bed of a draining creek and a downstream sedimentation-pond. Colloids mobilized by surface runoff during simulated rain events were characterized for their composition, structure and mode of As uptake using asymmetric flow field-flow fractionation coupled to inductively plasma mass spectrometry (AF4-ICP-MS) and X-ray absorption spectroscopy (XAS) at the As and Fe K-edges. Colloidal scorodite mobilized in surface runoff from the waste pile is acting as a mobile As carrier. In surface runoff from the river bed and the sedimentation pond, ferrihydrite was identified as the dominant As-bearing colloidal phase. The results from this study suggest that mobilization of As-bearing colloids by surface runoff may play an important role in the dispersion of As from metallurgical wastes deposited above ground and needs to be considered in risk assessment.The Spanish Ministry of Economy and Competitiveness (research project CGL 2010-17434) supported this study.A. Gomez-Gonzalez was supported by the Ph.D. Spanish FPI fellow-ship (BES-2011-046461) and by graduate students (EEBB-I-14-08063) programs.Peer reviewe

Limited ER quality control for GPI-anchored proteins

Endoplasmic reticulum (ER) quality control mechanisms target terminally misfolded proteins for ER-associated degradation (ERAD). Misfolded glycophosphatidylinositol-anchored proteins (GPI-APs) are, however, generally poor ERAD substrates and are targeted mainly to the vacuole/lysosome for degradation, leading to predictions that a GPI anchor sterically obstructs ERAD. Here we analyzed the degradation of the misfolded GPI-AP Gas1* in yeast. We could efficiently route Gas1* to Hrd1-dependent ERAD and provide evidence that it contains a GPI anchor, ruling out that a GPI anchor obstructs ERAD. Instead, we show that the normally decreased susceptibility of Gas1* to ERAD is caused by canonical remodeling of its GPI anchor, which occurs in all GPI-APs and provides a protein-independent ER export signal. Thus, GPI anchor remodeling is independent of protein folding and leads to efficient ER export of even misfolded species. Our data imply that ER quality control is limited for the entire class of GPI-APs, many of them being clinically relevantEspaña, Ministerio de Ciencia e Innovación BFU2014-59309-PEspaña, Ministerio de Ciencia e Innovación BFU2009-07290España, Junta de Andalucía P09-CVI-450

Energía gastada en el primer ciclo de histéresis como parámetro de selección de un biomaterial

Veinticuatro muestras de pericardio de ternera estabilizado, material similar al utilizado en la fabricación de velos de bioprótesis cardiacas, fueron sometidas a una prueba de esfuerzo a fatiga. Tras seis bloques de 100 ciclos a 1 MPa de presión máxima se rompieron 12 muestras, el 50%. La energía media gastada en este primer ciclo, en las muestras que sobrevivieron, fue de 0.16J, un valor inferior a la energía gastada en las muestra que terminaron rompiendo, 0.28J (p=0.005). Utilizando el cociente entre la energía disipada en el primer ciclo y el espesor medio de la muestra, con un valor de corte de 0.48J/mm para la selección de las mejores muestras, se obtiene un índice de validez del 87.5%, y un área bajo la curva ROC de 0.917. Este método no destructivo debe ayudar a los métodos ópticos en el reconocimiento y selección de las muestras más resistentes y en la obtención del material biológico más homogéne

Mechanical characterization of the human thoracic descending aorta Experiments and modelling

This work presents experiments and modelling aimed at characterising the passive mechanical behaviour of the human thoracic descending aorta. To this end, uniaxial tension and pressurisation tests on healthy samples corresponding to newborn, young and adult arteries are performed. Then, the tensile measurements are used to calibrate the material parameters of the Holzapfel constitutive model. This model is found to adequately adjust the material behaviour in a wide deformation range; in particular, it captures the progressive stiffness increase and the anisotropy due to the stretching of the collagen fibres. Finally, the assessment of these material parameters in the modelling of the pressurisation test is addressed. The implication of this study is the possibility to predict the mechanical response of the human thoracic descending aorta under generalised loading states like those that can occur in physiological conditions and/or in medical device application

Experimental demonstration of a magnetically induced warping transition in a topological insulator mediated by rare-earth surface dopants

Magnetic topological insulators (MTI) constitute a novel class of materials where the topologically protected band structure coexists with long-range ferromagnetic order, which can lead to the breaking of time-reversal symmetry (TRS), introducing a bandgap in the Dirac cone-shaped topological surface state (TSS). The gap opening in MITs has been predicted to be accompanied by a distortion in the TSS, evolving its warped shape from hexagonal to trigonal. In this work, we demonstrate such a transition by means of angle-resolved photoemission spectroscopy after the deposition of low concentrations of magnetic rare earths, namely Er and Dy, on the ternary three-dimensional prototypical topological insulator Bi$_2$Se$_2$Te. Signatures of the gap opening occurring as a consequence of the TRS breaking have also been observed, whose existence is supported by the observation of the aforementioned transition. Moreover, increasing the Er coverage results in a tunable p-type doping of the TSS. As a consequence, the Fermi level (E$_{\textrm{F}}$) of our Bi$_2$Se$_2$Te crystals can be gradually tuned towards the TSS Dirac point, and therefore to the magnetically induced bandgap; thus fulfilling two of the necessary prerequisites for the realization of the quantum anomalous Hall effect (QAHE) in this system. The experimental results are rationalized by a theoretical model where a magnetic Zeeman out-of-plane term is introduced in the hamiltonian governing the TSS band dispersion. Our results offer new strategies to control magnetic interactions with TSSs based on a simple approach and open up viable routes for the realization of the QAHE

Early Stepdown From Echinocandin to Fluconazole Treatment in Candidemia: A Post Hoc Analysis of Three Cohort Studies

[Background] There are no clear criteria for antifungal de-escalation after initial empirical treatments. We hypothesized that early de-escalation (ED) (within 5 days) to fluconazole is safe in fluconazole-susceptible candidemia with controlled source of infection.[Methods] This is a multicenter post hoc study that included consecutive patients from 3 prospective candidemia cohorts (2007–2016). The impact of ED and factors associated with mortality were assessed.[Results] Of 1023 candidemia episodes, 235 met inclusion criteria. Of these, 54 (23%) were classified as the ED group and 181 (77%) were classified as the non-ED group. ED was more common in catheter-related candidemia (51.9% vs 31.5%; P = .006) and episodes caused by Candida parapsilosis, yet it was less frequent in patients in the intensive care unit (24.1% vs 39.2%; P = .043), infections caused by Nakaseomyces glabrata (0% vs 9.9%; P = .016), and candidemia from an unknown source (24.1% vs 47%; P = .003). In the ED and non-ED groups, 30-day mortality was 11.1% and 29.8% (P = .006), respectively. Chronic obstructive pulmonary disease (odds ratio [OR], 3.97; 95% confidence interval [CI], 1.48–10.61), Pitt score > 2 (OR, 4.39; 95% CI, 1.94–9.20), unknown source of candidemia (OR, 2.59; 95% CI, 1.14–5.86), candidemia caused by Candida albicans (OR, 3.92; 95% CI, 1.48–10.61), and prior surgery (OR, 0.29; 95% CI, 0.08–0.97) were independent predictors of mortality. Similar results were found when a propensity score for receiving ED was incorporated into the model. ED had no significant impact on mortality (OR, 0.50; 95% CI, 0.16–1.53).[Conclusions] Early de-escalation is a safe strategy in patients with candidemia caused by fluconazole-susceptible strains with controlled source of bloodstream infection and hemodynamic stability. These results are important to apply antifungal stewardship strategies.This research forms part of an activity that has received funding from EIT Health. EIT Health is supported by the European Institute of Innovation and Technology (EIT), a body of the European Union that receives support from the European Union´s Horizon 2020 Research and Innovation Program. This study has been cofunded by the European Regional Development Fund. E. M.-G. (PI18/01061), P. P.-A. (“Rio Hortega” contract CM18/00132), M. F.-R. (“Miguel Servet” contract CP18/00073), and C. G.-V. (FIS PI18/01061) have received research grants from the Ministerio de Sanidad y Consumo, Instituto de Salud Carlos III.Peer reviewe

Experimental Demonstration of a Magnetically Induced Warping Transition in a Topological Insulator Mediated by Rare-Earth Surface Dopants [Dataset]

20 pages. -- I. Growth methods. -- II. Er deposition and X-ray photoemission spectroscopy (XPS) coverage calibration. -- III. Er/Bi2Se2Te extended ARPES and XPS data. -- IV. Dy/Bi2Se2Te extended ARPES and XPS data. -- V. Theoretical model. -- VI. Theoretical prove of the Fermi velocity anisotropy upon Er doping. -- VII. MDCs and EDCs fittings: band dispersion and gap opening. -- VIII. Structural characterization: LEED patters.Magnetic topological insulators constitute a novel class of materials whose topological surface states (TSSs) coexist with long-range ferromagnetic order, eventually breaking time-reversal symmetry. The subsequent bandgap opening is predicted to co-occur with a distortion of the TSS warped shape from hexagonal to trigonal. We demonstrate such a transition by means of angle-resolved photoemission spectroscopy on the magnetically rare-earth (Er and Dy) surface-doped topological insulator Bi2Se2Te. Signatures of the gap opening are also observed. Moreover, increasing the dopant coverage results in a tunable p-type doping of the TSS, thereby allowing for a gradual tuning of the Fermi level toward the magnetically induced bandgap. A theoretical model where a magnetic Zeeman out-of-plane term is introduced in the Hamiltonian governing the TSS rationalizes these experimental results. Our findings offer new strategies to control magnetic interactions with TSSs and open up viable routes for the realization of the quantum anomalous Hall effect.Peer reviewe

Recommendations of the Spanish Antibiogram Committee (COESANT) for selecting antimicrobial agents and concentrations for in vitro susceptibility studies using automated systems

Automated antimicrobial susceptibility testing devices are widely implemented in clinical microbiology laboratories in Spain, mainly using EUCAST (European Committee on Antimicrobial Susceptibility Testing) breakpoints. In 2007, a group of experts published recommendations for including antimicrobial agents and selecting concentrations in these systems. Under the patronage of the Spanish Antibiogram Committee (Comité Español del Antibiograma, COESANT) and the Study Group on Mechanisms of Action and Resistance to Antimicrobial Agents (GEMARA) from the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), and aligned with the Spanish National Plan against Antimicrobial Resistance (PRAN), a group of experts have updated this document. The main modifications from the previous version comprise the inclusion of new antimicrobial agents, adaptation of the ranges of concentrations to cover the EUCAST breakpoints and epidemiological cut-off values (ECOFFs), and the inference of new resistance mechanisms. This proposal should be considered by different manufacturers and users when designing new panels or cards. In addition, recommendations for selective reporting are also included. With this approach, the implementation of EUCAST breakpoints will be easier, increasing the quality of antimicrobial susceptibility testing data and their microbiological interpretation. It will also benefit epidemiological surveillance studies as well as the clinical use of antimicrobials aligned with antimicrobial stewardship programs.Los sistemas automáticos utilizados en el estudio de la sensibilidad a los antimicrobianos están introducidos en la mayoría de los laboratorios de Microbiología Clínica en España, utilizando principalmente los puntos de corte del European Committee on Antimicrobial Susceptibility Testing (EUCAST). En 2007, un grupo de expertos publicó unas recomendaciones para incluir antimicrobianos y seleccionar concentraciones en estos sistemas. Bajo el auspicio del Comité Español del Antibiograma (COESANT) y del Grupo de Estudio de los Mecanismos de Acción y Resistencia a los Antimicrobianos (GEMARA) de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica (SEIMC) y alineado con el Plan Nacional frente a la Resistencia a los Antibióticos (PRAN), un grupo de expertos ha actualizado dicho documento. Las principales modificaciones realizadas sobre la versión anterior comprenden la inclusión de nuevos agentes antimicrobianos, la adaptación de los rangos de concentraciones para cubrir los puntos de corte clínicos y los puntos de corte epidemiológicos (ECOFF) definidos por el EUCAST, y para la inferencia de nuevos mecanismos de resistencia. Esta propuesta debería ser considerada por los diferentes fabricantes y los usuarios cuando se diseñen nuevos paneles o tarjetas. Además, se incluyen recomendaciones para realizar informes selectivos. Con este enfoque, la implementación de los puntos de corte del EUCAST será más fácil, aumentando la calidad de los datos del antibiograma y su interpretación microbiológica. También será de utilidad para los estudios de vigilancia epidemiológica, así como para el uso clínico de los antimicrobianos, de acuerdo con los programas de optimización de uso de antimicrobianos (PROA)

Quasi-Neutral theory of epidemic outbreaks

Some epidemics have been empirically observed to exhibit outbreaks of all possible sizes, i.e., to be scalefree or scale-invariant. Different explanations for this finding have been put forward; among them there is a model for "accidental pathogens" which leads to power-law distributed outbreaks without apparent need of parameter fine tuning. This model has been claimed to be related to self-organized criticality, and its critical properties have been conjectured to be related to directed percolation. Instead, we show that this is a (quasi) neutral model, analogous to those used in Population Genetics and Ecology, with the same critical behavior as the voter-model, i.e. the theory of accidental pathogens is a (quasi)-neutral theory. This analogy allows us to explain all the system phenomenology, including generic scale invariance and the associated scaling exponents, in a parsimonious and simple way.Comment: 13 pages, 6 figures Accepted for publication in PLoS ONE the text have been modified in orden to improve the figure's resolutio