Online ISSN : 1884-4111
Print ISSN : 0033-8303
ISSN-L : 0033-8303
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Displaying 1-3 of 3 articles from this issue
Review Article
  • Tomoki Aoyama, Hiroshi Yasuda
    2023 Volume 72 Issue 3 Pages 211-217
    Published: November 15, 2023
    Released on J-STAGE: August 31, 2023

    As regenerative medicine becomes more active, the need for international transportation of regenerative medical products such as stem cells is increasing. Currently, international transport is mainly by air, but there are concerns about the effects of exposure to X-rays during security inspections at airports and cosmic radiation. Although the probability of cosmic radiation hitting cell nuclei during a single international flight to/from Japan is not high, it is necessary to minimize not only cell death and malignant transformation, but also the effects on the differentiation potential required of stem cells. Therefore, it is necessary to study the effects of low-dose radiation exposure during air transport and to develop transport containers and systems that can effectively shield cells from space radiation.

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  • Motoshi Shindou, Yoshihiro Saito, Shoko Goto, To-oru Yoshida, Takayuki ...
    2023 Volume 72 Issue 3 Pages 219-234
    Published: November 15, 2023
    Released on J-STAGE: September 08, 2023

    We decommissioned the Nishina Memorial Cyclotron Center that was mainly used for PET/PIXE study until 2019. The main body of the cyclotron and peripheral equipment were separated as radioactive waste. For the concrete in the accelerator room building, radioactivity analysis of concrete core samples using a Ge detector, dose measurement of concrete surface using a CsI scintillation survey meter with a lead shield, and activation calculation using PHITS code were performed. The PHITS calculation with detailed modeling well reproduced the measurement result. The activated part was evaluated to have a depth of 21 to 41 cm, and the scraped concrete was treated as radioactive waste. All the work took 22 months. A practical procedure is proposed for the estimation of activated part of the concrete.

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  • Tomoki Nagata, Mio Nagoya, Takaaki Ogura, Yuko Kurita, Natsuko I. Koba ...
    2023 Volume 72 Issue 3 Pages 235-245
    Published: November 15, 2023
    Released on J-STAGE: September 14, 2023

    Sodium (Na) exclusion is vital for plants to cope with salt stress, and the plasma membrane Na+/H+ antiporter, SALT OVERLY SENSITIVE 1 (SOS1), has been known to play a central role in this process although the function of this molecule is not completely understood. In this study, we performed 22Na+ radiotracer experiments to investigate the function of SOS1 in the mature root zone. Arabidopsis thaliana seedlings were placed on the gel medium, which had air gaps to separate the medium at the mature root zone from that at the root apex zone. Then, 22Na+ was added to the root apex zone for 4 h, and the radioactivity in the mature root zone with 5 mm in length and in the mature root zone gel was measured. As a result, we found that knock-out of SOS1 caused 22Na+ accumulation in the mature root zone and reduction of 22Na+ exclusion to the gel, demonstrating that Na+ delivered via the xylem is excluded to the rhizosphere by SOS1 in the mature root zone.

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