"Invisible" radioactive cesium atoms revealed: Pollucite inclusion in cesium-rich microparticles (CsMPs) from the Fukushima Daiichi Nuclear Power Plant.

Understanding radioactive Cs contamination has been a central issue at Fukushima Daiichi and other nuclear legacy sites; however, atomic-scale characterization of radioactive Cs in environmental samples has never been achieved. Here we report, for the first time, the direct imaging of radioactive Cs atoms using high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). In Cs-rich microparticles collected from Japan, we document inclusions that contain 27 - 36 wt% of Cs (reported as Cs2O) in a zeolite: pollucite. The compositions of three pollucite inclusions are (Cs1.86K0.11Rb0.19Ba0.22)2.4(Fe0.85Zn0.84X0.31)2.0Si4.1O12, (Cs1.19K0.05Rb0.19Ba0.22)1.7(Fe0.66Zn0.32X0.41)1.4Si4.6O12, and (Cs1.27K0.21Rb0.29Ba0.15)1.9(Fe0.60Zn0.32X0.69)1.6Si4.4O12 (X includes other cations). HAADF-STEM imaging of pollucite, viewed along the [111] zone axis, revealed an array of Cs atoms, which is consistent with a simulated image using the multi-slice method. The occurrence of pollucite indicates that locally enriched Cs reacted with siliceous substances during the Fukushima meltdowns, presumably through volatilization and condensation. Beta radiation doses from the incorporated Cs are estimated to reach 106 - 107 Gy, which is more than three orders of magnitude less than typical amorphization dose of zeolite. The atomic-resolution imaging of radioactive Cs is an important advance for better understanding the fate of radioactive Cs inside and outside of nuclear reactors damaged by meltdown events.

The association between brain morphological development and the quality of general movements.

AIM: To clarify the morphologic characteristics of the brain, which are the foundation of the emergence of general movements (GMs) in very-low-birth-weight infants. STUDY DESIGN: Prospective cohort study. GMs were scored according to a semiquantitative scoring system: the GMs optimality score (GMOS) at preterm and term ages. Brain magnetic resonance imaging (MRI) at term-equivalent age was scored using a validated scoring system (MRI score). We examined the relationship between the two scores by multiple regression analysis with relevant clinical background. SUBJECTS: We included 50 very-low-birth-weight infants cared for at Oita University Hospital from August 2012 to August 2018 who underwent MRI and GMs assessment. Their median gestational age and birth weight were 29w2d and 1145 g, respectively. RESULTS: The MRI score and systemic steroid administration were related to preterm GMOS, and the MRI score was related to term GMOS. The component cerebellum score and cortical grey matter score of the MRI score were associated with preterm GMOS, and the cerebellum and the cerebral white matter scores were associated with term GMOS. CONCLUSION: The quality of GMs was associated with brain morphological development. The co-evaluation of GMs and brain morphology leads to accurate developmental prediction.

Web accessibility support for visually impaired users using link content analysis.

Web pages are used for a variety of purposes. End users must understand dynamically changing content and sequentially follow page links to find desired material, requiring significant time and effort. However, for visually impaired users using screen readers, it can be difficult to find links to web pages when link text and alternative text descriptions are inappropriate. Our method supports the discovery of content by analyzing 8 categories of link types, and allows visually impaired users to be aware of the content represented by links in advance. This facilitates end users access to necessary information on web pages. Our method of classifying web page links is therefore effective as a means of evaluating accessibility.