[en] We used a computed tomography to look for evidence of cerebral changes in a three-year-10-month-old girl with subacute sclerosing panencephalitis (SSPE). The area of decreased density on CT corresponded to inflammatory and demyelinative lesions in the brain. CT scans seem to be a useful tool for more accurate assessment in the diagnosis of SSPE. (author)

[en] The optical properties of polyvinylpyrrolidone (PVP)-adsorbed and silica-coated Y₂O₃:Er,Yb nanoparticles produced by using PVP were studied for potential bio-applications of upconversion nanoparticles. We utilized PVP to better disperse Y₂O₃:Er,Yb nanoparticles in solution and to prepare silica-coated Y₂O₃:Er,Yb nanoparticles. The fluorescent intensity of PVP-adsorbed Y₂O₃:Er,Yb nanoparticles was 1.25 times higher than non-adsorbed Y₂O₃:Er,Yb nanoparticles, which was probably due to surface defects in Y₂O₃:Er,Yb nanoparticles being covered by the PVP. However, the fluorescent intensity of silica-coated Y₂O₃:Er,Yb nanoparticles decreased as silica layer thickness increased. This could be ascribed to the higher vibrational energy of PVP than that of the silica structure. Therefore, the optimum silica layer thickness is important in bio-applications to avoid deterioration of the optical properties of Y₂O₃:Er,Yb nanoparticles. - Highlights: • We prepared the silica-coated upconversion nanoparticles by using PVP. • We showed that PVP played an important role in coating nanoparticles. • PL intensity of silica-coated nanoparticles decreased as silica layer thickness increased