•EUROFER was exposed to static Pb-16Li to simulate low-flow WCLL blanket conditions.•Corrosion rate in static Pb-16Li at 550 °C by weight loss is 18 μm/yr.•Corrosion morphology shows Fe and Cr ...dissolution and W enrichment on the surface.•Cr depletion and preferential leaching is observed at the surface interface.
Liquid Pb-16Li eutectic alloy is the tritium breeding material in several breeding blanket concepts for European DEMO reactor, which are the Helium-Cooled Lithium-Lead (HCLL), the Water-Cooled Lithium-Lead (WCLL) and the Dual-Coolant Lithium-Lead (DCLL). RAFM (Reduced-Activation Ferritic/Martensitic) steels are considered as structural materials for breeding blankets in fusion reactors and EUROFER steel (9Cr-1.1W-0.2 V) is the European current choice for DEMO. Moreover, the WCLL European Test Blanket Module (TBM) to be installed in ITER will be manufactured in EUROFER. Here, the chemical compatibility of EUROFER in Pb-16Li is a major issue due to the dissolution of the material at high temperature in the liquid metal. In this work the corrosion of EUROFER in static Pb-16Li melt was investigated at 550 °C up to 8000 h of exposure to approximate low-flow WCLL blanket conditions. SEM-EDX analysis were performed on corroded samples to assess morphology and compositional changes occurring during the exposure. The corrosion was numerically evaluated by weight loss on samples exposed to various exposure times (2000, 4000 and 8000 h) and the corrosion rate for one year of exposure (8760 h) was extrapolated. The analysis by SEM-EDX showed that EUROFER mostly dissolved uniformly with a depletion of Cr and an enrichment of W at the near interface. The analysis of the weight loss provided an extrapolation of the corrosion rate of 18 μm/yr at 550 °C.
Human-driven extinctions can affect our understanding of evolution, through the nonrandom loss of certain types of species. Here, we explore how knowledge of a major evolutionary transition-the ...evolution of flightlessness in birds-is biased by anthropogenic extinctions. Adding data on 581 known anthropogenic extinctions to the extant global avifauna increases the number of species by 5%, but quadruples the number of flightless species. The evolution of flightlessness in birds is a widespread phenomenon, occurring in more than half of bird orders and evolving independently at least 150 times. Thus, we estimate that this evolutionary transition occurred at a rate four times higher than it would appear based solely on extant species. Our analysis of preanthropogenic avian diversity shows how anthropogenic effects can conceal the frequency of major evolutionary transitions in life forms and highlights the fact that macroevolutionary studies with only small amounts of missing data can still be highly biased.
On 2016 July 31 the ICECUBE collaboration reported the detection of a high-energy starting event induced by an astrophysical neutrino. Here, we report on a search for a gamma-ray counterpart to the ...ICECUBE-160731 event, made with the AGILE satellite. No detection was found spanning the time interval of 1 ks around the neutrino event time T0 using the AGILE "burst search" system. Looking for a possible gamma-ray precursor in the results of the AGILE-GRID automatic Quick Look procedure over predefined 48-hr time bins, we found an excess above 100 MeV between 1 and 2 days before T0, which is positionally consistent with the ICECUBE error circle, that has a post-trial significance of about . A refined data analysis of this excess confirms, a posteriori, the automatic detection. The new AGILE transient source, named AGL J1418+0008, thus stands as a possible ICECUBE-160731 gamma-ray precursor. No other space missions nor ground observatories have reported any detection of transient emission consistent with the ICECUBE event. We show that Fermi-LAT had a low exposure for the ICECUBE region during the AGILE gamma-ray transient. Based on an extensive search for cataloged sources within the error regions of ICECUBE-160731 and AGL J1418+0008, we find a possible common counterpart showing some of the key features associated with the high-energy peaked BL Lac (HBL) class of blazars. Further investigations on the nature of this source using dedicated SWIFT ToO data are presented.
Gamma-ray bursts (GRBs) are short, intense flashes of soft gamma-rays coming from the distant Universe. Long-duration GRBs (those lasting more than approximately 2 s) are believed to originate from ...the deaths of massive stars, mainly on the basis of a handful of solid associations between GRBs and supernovae. GRB 060614, one of the closest GRBs discovered, consisted of a 5-s hard spike followed by softer, brighter emission that lasted for approximately 100 s (refs 8, 9). Here we report deep optical observations of GRB 060614 showing no emerging supernova with absolute visual magnitude brighter than M(V) = -13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs. This demonstrates that some long-lasting GRBs can either be associated with a very faint supernova or produced by different phenomena.
The tidal disruption of a solar-mass star around a supermassive black hole has been extensively studied analytically and numerically. In these events, the star develops into an elongated ...banana-shaped structure. After completing an eccentric orbit, the bound debris falls into the black hole, forming an accretion disk and emitting radiation. The same process may occur on planetary scales if a minor body passes too close to its star. In the Solar System, comets fall directly into our Sun or onto planets. If the star is a compact object, the minor body can become tidally disrupted. Indeed, one of the first mechanisms invoked to produce strong gamma-ray emission involved accretion of comets onto neutron stars in our Galaxy. Here we report that the peculiarities of the 'Christmas' gamma-ray burst (GRB 101225A) can be explained by a tidal disruption event of a minor body around an isolated Galactic neutron star. This would indicate either that minor bodies can be captured by compact stellar remnants more frequently than occurs in the Solar System or that minor-body formation is relatively easy around millisecond radio pulsars. A peculiar supernova associated with a gamma-ray burst provides an alternative explanation.
Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). ...Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi2O3 liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi2O3 suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi2O3 sensors and compares them with recent Cu/Cu2O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu2O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi2O3 and Cu/Cu2O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu2O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu2O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C.
•Oxygen sensors for HLMs with different reference electrodes and stabilized zirconia electrolytes.•Calibration of oxygen sensors in oxygen-saturated HLMs in a wide temperature range.•Assessment of the accuracy and the minimum reading temperature of the oxygen sensors in HLMs.
An electronic eye (EE) for fast and easy evaluation of grape phenolic ripening has been developed. For this purpose, berries of different grape varieties were collected at different harvest times ...from veraison to maturity, then an amount of the derived must was deposited on a white sheet of absorbent paper to obtain a sort of paper chromatography. Thus, RGB images of the must spots were collected using a flatbed scanner and converted into one-dimensional signals, named colourgrams, which codify the colour properties of the images. The dataset of colourgrams was used to build calibration models to relate the colour of the images with the phenolic composition of the samples – determined by reference analytical methods – and therefore to follow the ripening trend. Satisfactory calibration models were obtained for the prediction of the most important parameters related to phenolic ripening of grapes, such as colour index, tonality, total anthocyanins content, malvidin-3-O-glucoside and petunidin-3-O-glucoside.
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•An electronic eye was developed to quantitatively estimate grape phenolic ripening.•Must spots deposited on absorbent paper sheets were imaged by a flatbed scanner.•Must images were standardized and converted into signals codifying colour properties.•These signals (colourgrams) were then used to build multivariate calibration models.•The models allowed to predict 9 out of 12 parameters related to grape ripening.
To evaluate a novel method, the colistin-MAC test, for phenotypic screening of acquired colistin resistance mediated by transferable mcr-1 resistance determinants, based on colistin MIC reduction in ...the presence of dipicolinic acid (DPA).
The colistin-MAC test consists in a broth microdilution method, in which colistin MIC is tested in the absence or presence of DPA (900 μg/mL). Overall, 74 colistin-resistant strains of Enterobacteriaceae (65 Escherichia coli and nine other species), including 61 strains carrying mcr-1-like genes and 13 strains negative for mcr genes, were evaluated with the colistin-MAC test. The presence of mcr-1-like and mcr-2-like genes was assessed by real-time PCR and end-point PCR. For 20 strains, whole-genome sequencing data were also available.
A ≥8-fold reduction of colistin MIC in the presence of DPA was observed with 59 mcr-1-positive strains, including 53 E. coli of clinical origin, three E. coli transconjugants carrying MCR-1-encoding plasmids, one Enterobacter cloacae complex and two Citrobacter spp. Colistin MICs were unchanged, increased or at most reduced by twofold with the 13 mcr-negative colistin-resistant strains (nine E. coli and four Klebsiella pneumoniae), but also with two mcr-1-like-positive K. pneumoniae strains.
The colistin-MAC test could be a simple phenotypic test for presumptive identification of mcr-1-positive strains among isolates of colistin-resistant E. coli, based on a ≥8-fold reduction of colistin MIC in the presence of DPA. Evaluation of the test with a larger number of strains, species and mcr-type resistance determinants would be of interest.
The potential of red blood cells (RBCs) loaded with iron oxide nanoparticles as a tracer material for magnetic particle imaging (MPI) has been investigated. MPI is an emerging, quantitative medical ...imaging modality which holds promise in terms of sensitivity in combination with spatial and temporal resolution. Steady-state and dynamic magnetization measurements, supported by semi-empirical modeling, were employed to analyze the MPI signal generation using RBCs as novel biomimetic constructs. Since the superparamagnetic iron oxide (SPIO) bulk material that is used in this study contains nanoparticles with different sizes, it is suggested that during the RBC loading procedure, a preferential entrapment of nanoparticles with hydrodynamic diameter ≤60 nm occurs by size-selection through the erythrocyte membrane pores. This affects the MPI signal of an erythrocyte-based tracer, compared to bulk. The reduced signal is counterbalanced by a higher in vivo stability of the SPIO-loaded RBCs constructs for MPI applications.
Nebulized therapy is the mainstay for treating obstructive airway diseases, but there is heightened concern about the potential risk for SARS-CoV-2 transmission during nebulization in COVID-19 ...patients.
To investigate the effects of 0.9% saline nebulization on SARS-CoV-2 RNA spreading in 11 COVID-19 patients (five females, mean age 62.45 ± 9.31 years); also to ascertain whether saline nebulization changed the number of exhaled bio-aerosol particles in six out of the 11 patients.
Air samples were collected using suction pumps equipped with 0.45 μm PTFE filters and positioned around the patient's bed. Exhaled particles were quantified by using an optical particle counter.
At baseline (i.e. before nebulization) SARS-CoV-2 was detected more frequently in the pumps close to the patient than in those far away. After saline nebulization, the detection of SARS-CoV-2 in the pumps close to the patient was comparable to that observed at baseline. In the pumps far from the patient, saline nebulization slightly, but not significantly, increased SARS-CoV-2 RNA detection compared to baseline. Overall, no significant changes in the SARS-CoV-2 RNA detection were observed after saline nebulization. At baseline, exhaled particle emission varied among patients, with two of them showing higher emission of particles than the remaining patients. Saline nebulization induced a marked decrease in exhaled particles in the two patients who displayed high emission at baseline, whereas no changes were observed in the remaining patients. Saline nebulization did not significantly change SARS-CoV-2 RNA spreading.
Saline nebulization does not significantly increase SARS-CoV-2 spreading.
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