Surface areas by positron annihilation spectroscopy

Positron annihilation spectroscopy (PAS) is a technique for measuring the length of time that a positron exists after being injected into a specific material. Lifetime measurements have been used for studying defects in metals. These imperfections affect the localized electron densities which in turn influence the lifetime of the positron before annihilation occurs. Electron density differences are also associated with surfaces. This paper describes the PAS technique and shows a correlation between positron annihilation intensities and surface areas of some fumed amorphous silicas

Advances in high-resolution studies of the chemical effects in the molybdenum L heavy-ion-induced x-ray satellite emission (HIXSE) spectra

High-resolution measurements of the molybdenum L heavy-ion-induced x-ray satellite emission (HIXSE) spectra of a series of Mo alloys and compounds have been obtained with a new, high-efficiency, high-resolution Bragg crystal spectrometer in the von Hamos geometry. The improved resolution (5 eV at 2.3 keV) is sufficient to reveal the L/sup n/M/sup m/ configuration lines in the L..cap alpha.. and L..beta.. hypersatellite bands. Both sets of lines exhibit the same trend in the variation of the relative yield distribution with the chemical environment as was observed for KL/sup n/ lines of lower Z targets. Difference spectra, using elemental molybdenum as a subtrahend, enhance the systematic variation. These results confirm the analysis and conclusions of lower resolution studies. They also indicate a potential for even greater sensitivity to the chemical environment

Correction to: Is diet partly responsible for differences in COVID-19 death rates between and within countries? (Clinical and Translational Allergy, (2020), 10, 1, (16), 10.1186/s13601-020-00323-0)

Following publication of the original article [1], the authors identified an error in the affiliation list. The affiliation of author G. Walter Canonica should have been split up into two affiliations: • Personalized Medicine, Asthma and Allergy – Humanitas Clinical and Research Center – IRCCS, Rozzano (MI), Italy • Department of Biomedical Sciences, Humanitas University, Pieve Emanuele (MI), Italy The corrected affiliation list is reflected in this Correction. © 2020, The Author(s)