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Infection control of dental stone cast is an important issue. Ozone is effective for disinfection against microorganisms and inactivation of viruses. However, there is little information regarding the use of ozone. We prepared 4 types of gypsum specimens and 3 types of disinfectants (4-5 ppm Ozonated water [OZW], 2% glutaraldehyde [GL], and 1% sodium hypochlorite [SH]). Gypsum specimens were immersed in each disinfectant for 5 and 10 min, and surface roughness was then examined using laser scanning microscopy. Surface microstructure was investigated using scanning electron microscopy. Immersion of gypsum specimens in SH, GL, and OZW increased the surface roughness to a maximum of 1.04, 0.37, and 0.30 μm, respectively, based on the difference between the average values of surface roughness before and after the disinfection procedure. The effects of OZW and GL were comparable. OZW is useful as a candidate for relatively safe disinfection of material for dental stone casts.

To understand the physics of the negative ion extraction/acceleration, the heat load density profile on the acceleration grid has been firstly measured in the ITER prototype accelerator where the negative ions are accelerated to 1 MeV with five acceleration stages. In order to clarify the profile, the peripheries around the apertures on the acceleration grid were separated into thermally insulated 34 blocks with thermocouples. The spatial resolution is as low as 3 mm and small enough to measure the tail of the beam profile with a beam diameter of ∼16 mm. It was found that there were two peaks of heat load density around the aperture. These two peaks were also clarified to be caused by the intercepted negative ions and secondary electrons from detailed investigation by changing the beam optics and gas density profile. This is the first experimental result, which is useful to understand the trajectories of these particles.

Quality control of mesenchymal stem cells is an important step before their clinical use in regenerative therapy. Among various characteristics of mesenchymal stem cells, reproducibility of population compositions should be analyzed according to characteristics, such as stem cell contents and differentiation stages. Such characterization may be possible by assessing the expression of several surface markers. Here we report our attempts to utilize antibody arrays for analyzing surface markers expressed in mesenchymal stem cell populations in a high-throughput manner. Antibody arrays were fabricated using a glass plate on which a micropatterned alkanethiol monolayer was formed. Various antibodies against surface markers including CD11b, CD31, CD44, CD45, CD51, CD73, CD90, CD105, and CD254 were covalently immobilized on the micropatterned surface in an array format to obtain an antibody array. To examine the feasibility of the array, cell binding assays were performed on the array using a mouse mesenchymal stem cell line. Our results showed that cell binding was observed on the arrayed spots with immobilized antibodies which exhibited reactivity to the cells in flow cytometry. It was further found that the density of cells attached to antibody spots was correlated to the mean fluorescent channel recorded in flow cytometry. These results demonstrate that data obtained by cell binding assays on the antibody array are comparable to those by the conventional flow cytometry, while throughput of the analysis is much higher with the antibody array-based method than flow cytometry. Accordingly, we concluded that the antibody array provides a high-throughput analytical method useful for the quality control of mesenchymal stem cells.