60Co in Cast Steel Matrix: a European Interlaboratory Comparison for the Characterisation of New Activity Standards for Calibration of Gamma-ray Spectrometers in Metallurgy

International audience; Two series of activity standards of Co-60 in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison among twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was cast from steel contaminated during production ("originally"), and the second, consisting of 15 similar discs, from artificially-contaminated ("spiked") steel. The reference activity concentrations of Co-60 in the cast steel standards were (1.077 +/- 0.019) Bq g(-1) on 1 January 2013 12h00 UT and (1.483 +/- 0.022) Bq g(-1) on 1 June 2013 12h00 UT, respectively

Prototype of a Radiation Source for Calibration of Installed Radiation Monitors

To prevent the unauthorised movement of radioactive material, radiation monitors are installed at checkpoints like road and rail border crossings, at airports or seaports and nuclear facilities. Trucks, trains, cars and persons pass through portal monitors that quickly measure radiation levels and issue an alarm if a certain investigation or alarm threshold is exceeded. Depending on the required probability of detecting a specified source, the threshold settings and performance tests can be tedious and time-consuming. We developed a prototype of a radiation source that can be used as a tool to facilitate such tests. In this work, we present the prototype and demonstrate its effectiveness.JRC.DDG.D.5-Neutron physic

Silver Nanoparticle‐Decorated Reduced Graphene Oxide Nanomaterials Exert Membrane Stress and Induce Immune Response to Inhibit the Early Phase of HIV‐1 Infection

Abstract Graphene‐based 2D nanomaterials exhibit unique physicochemical, electric, and optical properties that facilitate applications in a wide range of fields including material science, electronics, and biotechnology. Recent studies have shown that graphene oxide (GO) and reduced graphene oxide (rGO) exhibit antimicrobial effects on bacteria and viruses. While the bactericidal activity of graphene‐based nanomaterials is related to mechanical and oxidative damage to bacterial membranes, their antiviral activity has been less explored. Currently available experimental data are limited and suggest mechanical disruption of viral particles prior to infection. In this study, the antiviral properties of reduced GO‐based nanocomposites decorated with Ag nanoparticles (rGO‐Ag) are evidenced against human immunodeficiency virus‐1 pseudovirus used as an enveloped virus model. By combining biochemical and original single virus imaging approaches, it is shown that rGO‐Ag induces peroxidation of pseudoviral lipid membrane and that consequent alteration of membrane properties leads to a reduction in cell entry. In addition, rGO‐Ag is found to be efficiently internalized in the host cell leading to the elevated expression of pro‐inflammatory cytokines. Altogether, the presented results shed new light on the mechanisms of rGO‐Ag antiviral properties and confirm the high potential of graphene derivatives as an antimicrobial material for biomedical applications

60Co in Cast Steel Matrix: a European Interlaboratory Comparison for the Characterisation of New Activity Standards for Calibration of Gamma-ray Spectrometers in Metallurgy

Two series of activity standards of 60Co in cast steel matrix, developed for the calibration of gamma-ray spectrometry systems in the metallurgical sector, were characterised using a European interlaboratory comparison between twelve National Metrology Institutes and one international organisation. The first standard, consisting of 14 disc shaped samples, was casted from real contaminated steel, and the second, consisting of 15 similar discs, from artificially contaminated steel. The reference activity concentrations of 60Co in the cast steel standards were (1.077 ± 0.019) Bq∙g-1 and (1.483 ± 0.022) Bq∙g-1, respectively.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard