Individual Radiation Exposure Dose Due to Support Activities at Safe Shelters in Fukushima Prefecture

Immediately after the accidents in the nuclear power stations in Fukushima on March 11, the Japanese Government ordered the evacuation of the residents within a 20-km radius from the station on March 12, and asked various institutions to monitor the contamination levels of the residents. Hirosaki University, which is located 355 km north of Fukushima City, decided to send support staff to Fukushima. This report summarizes the results of the exposure of 13 individual teams from March 15 to June 20. The support teams surveyed more than 5,000 people during this period. Almost all subjects had external contamination levels of less than 13 kcpm on Geiger-Müller (GM) survey meter, which is categorized as “no contamination level.” The 1st team showed the highest external exposure dose, but the 4th team onward showed no significant change. Subsequently, the internal radiation exposure was measured using a whole body counter that indicated undetectable levels in all staff members. Although the measured external radiation exposure dose cannot have serious biological effects on the health of an individual, a follow-up study of the residents in Fukushima and other regions where the radioactive material has spread will be required for a long time

Allele-Specific Expression Analysis of PEG1/MEST in Head and Neck Squamous Cell Carcinomas

Genomic imprinting is an epigenetic feature that plays a significant role in carcinogenesis. In this study, we examined the expression status of an imprinted gene, paternally expressed gene 1/mesoderm-specific transcript PEG1/MEST, in 38 cases of head and neck squamous cell carcinomas (HNSCCs) and in 17 oral squamous cancer cell lines. Loss of imprinting (LOI) of PEG1/MEST was found in 8 of 10 (80%) in tumor specimens, and 6 of 10 (60%) informative cases even in the extracted normal tissue specimens. As for the oral squamous cancer cell lines, LOI was detected in 5 of 8 (62.5%) informative cases in PEG1/MEST. Thus, these data showed that abnormal expression of PEG1/MEST was found at a high frequency in the tumor, the extracted normal tissue specimens and the oral squamous cancer cell lines. PEG1/MEST LOI in extracted normal tissue specimens may have a potential individual cancer risk for HNSCC

Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. The large Japanese field mice (Apodemus speciosus) are rodents endemic to, and distributed throughout, Japan. This wild rodent live in and around the ex-evacuation zone on the ground surface and/or underground. In this study, we evaluated the effect of chronic radiation exposure associated with FDNPP accident on the testes of large Japanese field mice. Morphological analysis and electron-prove X-ray microanalysis (EPMA) was undertaken on the testes. Morphological analysis of testes based on H&E staining showed that the spermatogenesis was observed normally in the breeding season of wild mice in the heavily contaminated area. However, caesium (Cs) was not detected in all testes of wild mice from FDNPP ex-evacuation zone. In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, we could not detect radiation effects on the spermatogenesis and Cs in the examined large Japanese field mice testes following chronic radiation exposure associated with the FDNPP accident

Precision of scoring radiation-induced chromosomal aberrations and micronuclei by unexperienced scorers

Purpose: Dose assessment plays an important role in case of radiological accidents and can be performed by scoring structural changes of chromosome morphology induced in cells by ionizing radiation. The results of such a test are biased by scorer experience, therefore, simple to learn assays are recommended to be used when fast analysis of a large amount of data is needed. The aim of this study was to compare the performance of two radiobiological assays – chromosomal aberrations and micronuclei – by unexperienced scorers with the reference values generated by an expert. Materials and methods: Each participant of an EU-funded two-week radiobiology course was asked to score Chinese hamster ovary cells exposed to gamma radiation up to 4 Gy. The congruence of students’ and expert’s scores at each dose and the coherence of the dose-response curve parameters between the students were investigated. Results: Micronucleus test tended to be faster and easier to learn than scoring chromosomal aberrations. However, both assays carried out by inexperienced students showed reasonable dose-response curves. Conclusions: In the case of a large radiological accident involving many casualties, the unexperienced scorers would support the process of biodosimetric triage by cytogenetic biological dosimetry

Precise Measurement of Cosmic-Ray Proton and Helium Spectra with the BESS Spectrometer

We report cosmic-ray proton and helium spectra in energy ranges of 1 to 120 GeV and 1 to 54 GeV/nucleon, respectively, measured by a balloon flight of the BESS spectrometer in 1998. The magnetic-rigidity of the cosmic-rays was reliably determined by highly precise measurement of the circular track in a uniform solenoidal magnetic field of 1 Tesla. Those spectra were determined within overall uncertainties of +-5 % for protons and +- 10 % for helium nuclei including statistical and systematic errors.Comment: 12 pages, 4 figure

Measurements of Cosmic-ray Low-energy Antiproton and Proton Spectra in a Transient Period of the Solar Field Reversal

The energy spectra of cosmic-ray low-energy antiprotons and protons have been measured by BESS in 1999 and 2000, during a period covering the solar magnetic field reversal. Based on these measurements, a sudden increase of the antiproton to proton flux ratio following the solar magnetic field reversal was observed, and it generally agrees with a drift model of the solar modulation.Comment: 4 pages, 4 figures, revised version accepted for publication in Phys. Rev. Let

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216