59 research outputs found

    Solvability of Superlinear Fractional Parabolic Equations

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    We study necessary conditions and sufficient conditions for the existence of local-in-time solutions of the Cauchy problem for superlinear fractional parabolic equations. Our conditions are sharp and clarify the relationship between the solvability of the Cauchy problem and the strength of the singularities of the initial measure

    Graphical Evaluation Method for Void Distribution in Direct Energy Deposition

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    AbstractDirect energy deposition (DED) process attracts attention from industries because of its applicability to production of complex shape parts. However, technical challenges still remain in DED, such as void evolution inside of the produced object. This paper provides a new graphical evaluation method of void distribution. Binarizing a cross-sectional image of the cladded object and applying a 2-dimensional Gaussian window, the void distribution rate is separately evaluated in each local area on the cross section. To clarify the relation between void evolution and deposition condition in Inconel 625, the void distribution is experimentally evaluated through the various tests

    Contribution of light and electron microscopy in the identification of morphological alterations in large Japanese field mouse (Apodemus speciosus) testes exposed to low-dose-rate radiations

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    Ionizing radiation affects biological systems, resulting in an increased risk of cancer and mutagenesis. Male reproductive function is sensitive to ionizing radiation, with implications connected to infertility. Following the Nuclear Power Plants accident of Fukushima in 2011, there was great attention regarding exposure damage to low-dose-rate (LDR) radiation on the reproductive system. This preliminary study aimed to evaluate the role of light (LM) and transmission electron microscopies (TEM) to identify the potential effects of LDR radio-exposure on the morphology of large Japanese field mouse (Apodemus speciosus) testes living in the Fukushima Daiichi Nuclear Power Plant (FDNPP) ex-evacuation area. After collection samples were subjected to the standard preparative for LM and TEM. The testicular parenchyma was characterized by numerous seminiferous tubules, delimited by a thick and continuous basal lamina. Basally, the germinal epithelium presented round and pale spermatogonia, primary spermatocytes; while, more adluminally, round and elongated spermatids were at different phases of development. Pale and irregular Sertoli cells were interspersed among germ cells. Occasionally, cytoplasmatic holes interrupted the nuclear membrane integrity in spermatocytes and spermatids. Residual bodies were seen at the luminal surface. In conclusion, this study suggests that LM and TEM analysis are useful in evaluating potential morphological features in the male reproductive system after LDR exposure

    Porencephaly in a Cynomolgus Monkey (Macaca Fascicularis)

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    Porencephaly was observed in a female cynomolgus monkey (Macaca fascicularis) aged 5 years and 7 months. The cerebral hemisphere exhibited diffuse brownish excavation with partial defects of the full thickness of the hemispheric wall, and it constituted open channels between the lateral ventricular system and arachnoid space. In addition, the bilateral occipital lobe was slightly atrophied. Histopathologically, fibrous gliosis was spread out around the excavation area and its periphery. In the roof tissue over the cavity, small round cells were arranged in the laminae. They seemed to be neural or glial precursor cells because they were positive for Musashi 1 and negative for NeuN and GFAP. In the area of fibrous gliosis, hemosiderin or lipofuscin were deposited in the macrophages, and activated astroglias were observed extensively around the excavation area

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

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    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

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    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
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