Radiation Exposure Dose Distribution of Workers Engaged in Decontamination and Related Work Following the Fukushima Nuclear Disaster.

ABSTRACT: Since the Fukushima nuclear disaster in March 2011, decontamination operations have been conducted across a wide area of Japan. The Japanese System of Registration and Management of Radiation Exposure Doses for Decontamination and Related Work, which was launched in November 2013, is administered by the Radiation Effects Association with the participation of prime contractors who perform decontamination and related work. This study aims to investigate the radiation exposure dose distribution of workers engaged in decontamination and related work, using data obtained from the above registration system. We analyzed the radiation exposure dose distributions among workers in 11 Fukushima prefectural municipalities (Futaba, Iitate, Katsurao, Kawamata, Kawauchi, Namie, Naraha, Minamisoma, Okuma, Tamura, and Tomioka) from 2013 to 2018. The mean radiation exposure doses of workers in each municipality were generally low, although a Kruskal-Wallis test showed a significant regional difference in the figures. The highest mean dose was 0.5 mSv in Okuma in 2018, and the second highest was that of Futaba. The workers engaged in the land development and construction of the interim facilities may have been exposed to more radiation than other workers across 11 Fukushima prefectural municipalities. Following large-scale nuclear accidents or radiation emergencies, radiation dose monitoring and health management for each worker need to be optimized according to their work assignments.

Deletion of the Tensin2 SH2-PTB domain, but not the loss of its PTPase activity, induces podocyte injury in FVB/N mouse strain.

Tensin2 (TNS2) is a focal adhesion-localized protein possessing N-terminal tandem protein tyrosine phosphatase (PTPase) and C2 domains, and C-terminal tandem Src homology 2 (SH2) and phosphotyrosine binding (PTB) domains. Genetic deletion of Tns2 in a susceptible murine strain leads to podocyte alterations after birth. To clarify the domain contributions to podocyte maintenance, we generated two Tns2-mutant mice with the genetic background of the susceptible FVB/NJ strain, Tns2∆C and Tns2CS mice, carrying a SH2-PTB domain deletion and a PTPase domain inactivation, respectively. The Tns2∆C mice developed massive albuminuria, severe glomerular injury and podocyte alterations similarly to those in Tns2-deficient mice. In contrast, the Tns2CS mice showed no obvious phenotypic abnormalities. These results indicate that the TNS2 SH2-PTB domain, but not its PTPase activity, plays a role in podocyte maintenance. Furthermore, in a podocyte cell line, the truncated TNS2 mutant lacking the SH2-PTB domain lost the ability to localize to focal adhesion. Taken together, these data suggest that TNS2 recruitment to focal adhesion is required to maintain postnatal podocytes on a susceptible genetic background.

Hyper-mobility of water around actin filaments revealed using pulse-field gradient spin-echo 1H NMR and fluorescence spectroscopy.

This paper reports that water molecules around F-actin, a polymerized form of actin, are more mobile than those around G-actin or in bulk water. A measurement using pulse-field gradient spin-echo (1)H NMR showed that the self-diffusion coefficient of water in aqueous F-actin solution increased with actin concentration by ∼5%, whereas that in G-actin solution was close to that of pure water. This indicates that an F-actin/water interaction is responsible for the high self-diffusion of water. The local viscosity around actin was also investigated by fluorescence measurements of Cy3, a fluorescent dye, conjugated to Cys 374 of actin. The steady-state fluorescence anisotropy of Cy3 attached to F-actin was 0.270, which was lower than that for G-actin, 0.334. Taking into account the fluorescence lifetimes of the Cy3 bound to actin, their rotational correlation times were estimated to be 3.8 and 9.1ns for F- and G-actin, respectively. This indicates that Cy3 bound to F-actin rotates more freely than that bound to G-actin, and therefore the local water viscosity is lower around F-actin than around G-actin.