•W samples were pre-irradiated with 4.8 and 20MeV W ions to various displacements per atom (dpa).•Under following exposure to D plasmas radiation-induced defects were occupied by diffusing D ...atoms.•At ⩾0.1dpa, the D concentration in the damage zone demonstrated weak dependence on the damage level.
W samples were irradiated at 300 and 573K with 4.8 and 20MeV W ions to displacement damage levels in the range from 0.022 to 50 displacements per atom at the damage peak. 50μm thick W samples were exposed to high flux D plasma at 550K on the side opposite to the damaged one, whereas 2mm thick W samples were exposed to low flux D plasma at 403K on the damaged side. Trapping of deuterium at displacement damage was examined by the D(3He, p)4He nuclear reaction with 3He energies between 0.69 and 4.0MeV allowing determination of the D concentration up to a depth of 6μm. It was found that (i) at the damage level above 0.1dpa, the concentration of the W-ion-induced defects responsible for trapping of diffusing D atoms depended very weakly on the numbers of displacements per atom, and (ii) the quasi-saturation concentration of the defects decreased by a factor of two as the W-ion irradiation temperature increased from 300 to 573K.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The pituitary gonadotropins (GtHs), follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are key regulators of gametogenesis in teleosts. However, little is known about the physiological ...mechanisms by which GtHs regulate asynchronous oocyte development in multiple-spawning marine fishes. We cloned cDNAs encoding GtH receptors (FSHR and LHR) from chub mackerel (Scomber japonicus). FSH and LH were purified by anion-exchange chromatography, gel filtration, and concanavalinA-agarose. When expressed in mammalian cells, FSHR and LHR responded strongly to their own ligands. By separating LH into two subunits by the use of reverse-phase chromatography, we found that the beta-subunit is responsible for signal transduction and the alpha-subunit may be important for holding hormone-receptor complex. In situ hybridization showed that only fshr was expressed in prefollicle and granulosa cells in oocytes at the perinucleolus and cortical alveolus stages, suggesting that FSH is involved in the primary and early secondary growth of oocytes. In ovarian follicles during vitellogenesis, both fshr and lhr were expressed in granulosa and thecal cells, and lhr was strongly expressed during germinal vesicle migration (GVM). Real-time PCR analysis of stage-dependent fshr and lhr expression showed that fshr expression was high in ovarian follicles throughout vitellogenesis and decreased during GVM, whereas lhr expression was low in early vitellogenesis, but increased markedly in the late phase of vitellogenesis, remaining high during GVM. These findings suggest that switching of the expression of FSHR to LHR controls the effects of FSH and/or LH on vitellogenesis and final oocyte maturation via steroid production in granulosa and thecal cells.
We improved an established one-step multiplex RT-PCR method to detect six orthotospoviruses that infect Solanaceae plants (tomato spotted wilt virus TSWV, newly reported tomato zonate spot virus ...TZSV, impatiens necrotic spot virus INSV, chrysanthemum stem necrosis virus CSNV, watermelon silver mottle virus WSMoV, capsicum chlorosis virus CaCV). Specific primer sets for one-step multiplex RT-PCR were designed for TSWV, TZSV, INSV, CSNV, WSMoV, and CaCV, and this optimized RT-PCR amplified DNA fragments corresponding to the target virus species: TSWV (831 bp), TZSV (734 bp), INSV (592 bp), CSNV (502 bp), WSMoV (395 bp), CaCV (324 bp). All combinations of orthotospoviruses were detected in mixed samples. The method was applied to Solanaceae plants infected with orthotospoviruses under field conditions.
Samples of polycrystalline ITER-grade W and recrystallized W were irradiated at room temperature with 20MeV W ions to displacement damage up to 0.5dpa. The damaged W samples were then exposed to (i) ...D neutrals at 403–573K and (ii) D2 gas at 673–1073K and pressures of 1.2 and 100kPa. Trapping of deuterium in the damage zone was examined by the D(3He, p)4He nuclear reaction with 3He energies between 0.69 and 4.0MeV allowing determination of the D concentration up to a depth of 6μm. It has been found that generation of the W-ion-induced displacement damage leads to accumulation of deuterium in the damage zone up to concentration depending on the exposure temperature and, at temperatures ⩾673K, on the D2 gas pressure. Thermal desorption spectra allowed a conclusion that deuterium is mainly accumulated in the form of D atoms bound to inner walls of vacancy clusters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► W samples were irradiated with 20
MeV W ions to 0.89
dpa at the damage peak. ► The W samples were exposed to pure D and He-seeded D plasmas. ► Displacement damage significantly increases the D ...concentration in the damage zone. ► After exposure to D plasma, the D concentration is higher than that after He–D plasma.
Samples prepared from polycrystalline ITER-grade tungsten were damaged by irradiation with 20
MeV
W ions at room temperature to a fluence of 1.4
×
10
18
W/m
2. Due to the irradiation, displacement damage peaked near the end-of-range, 1.35
μm beneath the surface, at 0.89 displacements per atom. The damaged as well as undamaged W samples were then exposed to low-energy, high-flux (10
22
D/m
2
s) pure D and helium-seeded D plasmas to an ion fluence of 3
×
10
26
D/m
2 at various temperatures. Trapping of deuterium was examined by the D(
3He,p)
4He nuclear reaction at
3He energies varied from 0.69 to 4.0
MeV allowing determination of the D concentration at depths up to 6
μm. It has been found that (i) addition of 10% helium ions into the D plasma at exposure temperatures of 440–650
K significantly reduces the D concentration at depths of 0.5–6
μm compared to that for the pure plasma exposure; (ii) generation of the W-ion-induced displacement damage significantly increases the D concentration at depths up to 2
μm (i.e., in the damage zone) under subsequent exposures to both pure D and D–He plasmas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•W and W–5%Re were exposed to low-energy, high flux D plasma at various temperatures.•The temperature dependences of the D retention in these two materials diverged.•It is suggested that ductility of ...W and W–5%Re materials influences the D retention.
Surface topography and deuterium retention in polycrystalline hot-rolled W and W–5%Re have been examined after exposure to a low-energy (76eV), high flux (around 1022D/m2s) deuterium plasma to an ion fluence of 1026D/m2 at various temperatures. The methods used were confocal laser scanning microscopy and the D(3He, p)4He nuclear reaction at 3He energies varied from 0.69 to 4.0MeV. During exposure to the D plasma at temperatures in the range from 348 to 673K, small blisters of size in the range from about 1 to about 15μm, depending on the exposure temperature, are formed on the W and W–5%Re surfaces. In the W–5%Re, the deuterium retention demonstrates its maximum at exposure temperature of 463K, while in the W this maximum is shifted to 523K. A difference in the temperature dependence of the D retention for the W and W–5%Re is explained, as a rough approximation, by temperature dependences of the ductility of these materials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Cesium corrosion process in Fe–Cr steel Sasaki, K.; Tanigaki, T.; Matsuyama, M. ...
Journal of nuclear materials,
10/2013, Volume:
441, Issue:
1-3
Journal Article
Peer reviewed
A cesium corrosion out-pile test was performed to Fe–Cr steel in a simulated fuel pin environment. In order to specify the corrosion products, the corroded area was analyzed by scanning electron ...microscopy (SEM) and transmission electron microscopy (TEM). A cesium corrosion process in Fe–Cr steel was successfully developed proceeding from both experimental results and thermochemical consideration. The corroded area was mainly formed by Fe layer and Fe depleted oxidized layer. The Fe depleted oxidized layer was formed by Cr0.5Fe0.5 and Cr2O3. The presumed main corrosion reactions were 2Cr+23O2→Cr2O3(ΔG650°C=-894.1kJ/mol) and Cr23C6+46Cs+46O2→23Cs2CrO4+6C(ΔG650°C=-25018.1kJ/mol). Factors of these reactions are chromium, carbon, oxygen and cesium. Therefore, cesium corrosion progression must be dependent on the chromium content, carbon content in the steel, the supply rate of oxygen and temperature which correlated with the diffusion rate of cesium and oxygen into the specimen.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The objective of this study was to investigate the impact of the most commonly cited factors that may have influenced infants' gut microbiota profiles at one year of age: mode of delivery, ...breastfeeding duration and antibiotic exposure. Barcoded V3/V4 amplicons of bacterial 16S-rRNA gene were prepared from the stool samples of 52 healthy 1-year-old Australian children and sequenced using the Illumina MiSeq platform. Following the quality checks, the data were processed using the Quantitative Insights Into Microbial Ecology pipeline and analysed using the Calypso package for microbiome data analysis. The stool microbiota profiles of children still breastfed were significantly different from that of children weaned earlier (P<0.05), independent of the age of solid food introduction. Among children still breastfed, Veillonella spp. abundance was higher. Children no longer breastfed possessed a more 'mature' microbiota, with notable increases of Firmicutes. The microbiota profiles of the children could not be differentiated by delivery mode or antibiotic exposure. Further analysis based on children's feeding patterns found children who were breastfed alongside solid food had significantly different microbiota profiles compared to that of children who were receiving both breastmilk and formula milk alongside solid food. This study provided evidence that breastfeeding continues to influence gut microbial community even at late infancy when these children are also consuming table foods. At this age, any impacts from mode of delivery or antibiotic exposure did not appear to be discernible imprints on the microbial community profiles of these healthy children.
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