Relationship between Individual External Doses, Ambient Dose Rates and Individuals' Activity-Patterns in Affected Areas in Fukushima following the Fukushima Daiichi Nuclear Power Plant Accident.

The accident at Fukushima Daiichi Nuclear Power Plant on March 11, 2011, released radioactive material into the atmosphere and contaminated the land in Fukushima and several neighboring prefectures. Five years after the nuclear disaster, the radiation levels have greatly decreased due to physical decay, weathering, and decontamination operations in Fukushima. The populations of 12 communities were forced to evacuate after the accident; as of March 2016, the evacuation order has been lifted in only a limited area, and permanent habitation is still prohibited in most of the areas. In order for the government to lift the evacuation order and for individuals to return to their original residential areas, it is important to assess current and future realistic individual external doses. Here, we used personal dosimeters along with the Global Positioning System and Geographic Information System to understand realistic individual external doses and to relate individual external doses, ambient doses, and activity-patterns of individuals in the affected areas in Fukushima. The results showed that the additional individual external doses were well correlated to the additional ambient doses based on the airborne monitoring survey. The results of linear regression analysis suggested that the additional individual external doses were on average about one-fifth that of the additional ambient doses. The reduction factors, which are defined as the ratios of the additional individual external doses to the additional ambient doses, were calculated to be on average 0.14 and 0.32 for time spent at home and outdoors, respectively. Analysis of the contribution of various activity patterns to the total individual external dose demonstrated good agreement with the average fraction of time spent daily in each activity, but the contribution due to being outdoors varied widely. These results are a valuable contribution to understanding realistic individual external doses and the corresponding airborne monitoring-based ambient doses and time-activity patterns of individuals. Moreover, the results provide important information for predicting future cumulative doses after the return of residents to evacuation order areas in Fukushima.

Evaluation of dose from external irradiation for individuals living in areas affected by the Fukushima Daiichi Nuclear Plant accident.

In order to effectively and appropriately manage external radiation doses in the affected areas of Fukushima, it is important to identify when, where and how much exposure occurred. It is also necessary to quantitatively measure external exposure and air dose rates for different activity patterns in individuals living and working in Japanese-style buildings. The authors used a new personal dosemeter (D-shuttle) along with a global positioning system and geographical information system to relate personal dose rate with activity patterns and air dose rate. Hourly individual doses obtained by D-shuttle can provide an effective communication tool for those who want to identify when and how much exposure occurs. Personal monitoring of 26 volunteers showed that personal doses obtained from D-shuttle were ∼30% of cumulative air dose estimated by data from the airborne monitoring survey. This analysis showed that, for most study volunteers, the exposure from staying at home represented about half of the total cumulative dose. This suggests that even though the peak exposure doses may be observed outside of working hours, to develop appropriate countermeasures for external dose reduction, it is thus important to identify the contributions of individuals' time-activities. This study provides a valuable basis for developing a realistic and pragmatic method to estimate external doses of individuals in Fukushima.

Evaluation of quality of life among patients with ischemic heart disease who practiced self-care activities at home after elective percutaneous coronary intervention.

The present study compares health-related QOL between patients who practiced self-care activities comprising exercise and diet at home for at least 6 months (SA group; n = 84) after elective PCI and those who did not (NA group; n = 54). Health-related (HR) QOL was measured using the SF-36 questionnaire. Scores for two mental and three physical parameters of the HRQOL were increased in the SA, but not in the NA group. These findings indicated that the QOL was far superior among patients who exercised and consumed an appropriate diet at home for at least 6 months after elective PCI compared with those who did not.

[Chemical profiles of methylpyrazines contained in commercially available natto].

Structures and amounts of methylpyrazines contained in commercial natto, a fermented soybean food in Japan, were determined using HPLC equipped with an acid-resistant reversed phase column, Capcell Pak C18 ACR (Shiseido). Mobile phase solvent mixtures consisted of acidic phosphate buffer solution (pH 2.0) containing 2% acetonitrile gave satisfactory results with baseline separation of the authentic specimens, such as naked pyrazine, monomethylpyrazine, 2,3-, 2,5-, and 2,6-dimethylpyrazine, trimethylpyrazine, and tetramethylpyrazine. We used the mobile-phase solvent with a flow rate of 1 ml/min at 15.0 degrees C. Before HPLC, commercial natto samples were treated with water to prepare diluted suspensions of surface mucous materials. The suspensions were treated on Sep-Pac C18 Cartridges (Waters) with phosphate buffer solutions containing 2-7% acetonitrile. The extracts were then injected into the analytical column to obtain chromatograms that were used to determine the structures and amounts of methylpyrazines. The results showed that a commercialiy packed natto contains a considerable amount of 2,5-dimethylpyrazine instead of the tetrametyl- and trimethylpyrazines in the traditional products. This may be a result of recent efforts of natto makers whose interests have been focused on new methods for preparing odorless products.

Pre-incubation with hyaluronan reduces cellular damage after cryopreservation in densely cultured cell monolayers.

Reduction of cellular damage in densely cultured cell monolayers after cryopreservation by pre-incubation with hyaluronan (HA) was investigated. Monolayers of human dermal fibroblasts were cultured for 24 h at a density of 0.5×104 or 5×104 cells/cm2. The following two experimental conditions were compared: cells incubated with or without 0.5% w/w HA solution for 6 h. Samples were frozen from 4 to -80°C at 0.3 or 3°C/min in a cryoprotectant solution containing 10% w/w dimethyl sulfoxide, cooled down below -185°C, and then thawed. Post-thaw cell viability was evaluated by the fluorescent double-staining technique using a fluorescence microscope, and cellular uptake of the fluorescein-isothiocyanate-labeled HA after pre-incubation was also observed. Cell viability decreased with increasing cell density at both cooling rates without preliminary HA incubation. However, cell viability did not decrease at either cooling rate with preliminary HA incubation. Cellular HA uptake was observed. Pre-incubation with HA reduces cellular damage in densely cultured cell monolayers.