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  • Author or Editor: H Nakamura x
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Flour particle size distribution is a major factor affecting the milling behaviour in common wheats (Triticum aestivum L.). This study evaluated a new method to evaluate the milling behaviour of Japanese wheat varieties, and determine the relationship between flour yield and median flour particle size. To investigate the higher flour yielding varieties in Japanese wheats, the flour yield of one hundred sixty-five Japanese common wheat varieties were investigated in relation to median and mean flour particle size, and also, the flour particle size distribution patterns as determined by laser diffraction. The results showed that hard and soft wheat varieties differed in median flour particle size and particle distribution patterns. Eighty percent of the Japanese wheat varieties had soft or medium-soft particle size distribution patterns. Also, flour yield was most strongly associated with the median flour particle size in the flour samples. These results indicate the potential to develop a flour yield evaluation method in Japanese udon-noodle wheat varieties using laser diffraction methods, and that median flour particle size analysis could be a useful indicator in flour quality for udon-noodle wheat breeding and evaluation.

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Flour particle size distribution is a major factor affecting the milling behavior in common wheats (Triticum aestivum L.). Also, a previous study has revealed a relationship between flour yield and median flour particle size of Japanese wheats. However, the genetic base of Japanese common wheat is narrow and will need to be broadened. Therefore, in order to help develop the genetic resource for higher flour yields in Japanese wheat breeding, the flour yield of one hundred and seventy Chinese common wheats were investigated in relation to the median flour particle size and the flour particle size distribution patterns as determined by laser diffraction. The results showed significant differences in the median flour particle size and distribution patterns of Chinese wheats and the Japanese wheats that had been analyzed in a previous study. In particular, 45% of Chinese wheats were categorized as hard wheats, but only 4% as soft wheats. In contrast, the previously analyzed Japanese wheat proportions were 20% and 25%, respectively. The results show that analysis of median flour particle size distribution by laser diffraction is a simple but effective tool for measuring and selecting the good flour milling quality in Chinese wheat genetic resources. In addition, the major differences between the Japanese and Chinese wheats highlighted in this study occurred despite the fact that it is well known that Chinese common wheats contributed to modern Japanese wheat varieties. The differences may be explained by either the founder effect or by a selective bottleneck in Japanese wheat genetic resources.

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Soil-to-plant transfer factors of 31 stable elements were determined by neutron activation analysis. The transfer factor is one of the important parameters used to estimate the internal radiation dose from radionuclides through food ingestion. In the present study, 12 species of agricultural plants such as root crops, fruit vegetables, green vegetables and pasture grasses, and their soils were collected from 150 farm fields in Aomori prefecture, Japan. The elements described are those that could be detected by this method, which include both essential and nonessential elements for plant growth. The concentrations of individual elements in the cultivated soil samples for each plant were similar in values and their standard deviations were within one order of magnitude, because of the relatively narrow geographic sampling area. The elements were classified into two groups, each having different transfer factor characteristics. In the first group of elements there was an inverse correlation between the transfer factors and the concentrations of elements in the soil, especially for Cl, K and Ca. In the second group, especially Sc and Co, however, the transfer factors were independent of the concentrations of elements in the soil.

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The distribution ratio of neodymium(III) in extraction with mono(2-ethylhexyl)-phosphoric acid was determined as a function of extractant and Nd(III) concentrations, and effect of co-existing DEHPA was studied. A characteristic extraction of a tracer quantity of Nd(III) was found at an extractant concentration of approximately 0.01 M. Di(2-ethylhexyl)phosphoric acid depresses the extraction of Nd(III) in MEHPA of a concentration of 0.01M, but enhances it at higher concentrations of MEHPA. Owing to the high Df values against lanthanides(III) and an excellent radiation stability, the synergistic combination of MEHPA-DEHPA, preferably at a DEHPA/MEHPA mole ratio of 3, was concluded to be applicable to the isolation of lanthanides (and actinides) from highly acidic solutions.

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Effects of radiation on the extraction system composed of DEHPA extractant and DTPA aqueous solution containing nitrate were studied by measuring distribution ratios of Am(III) and Nd(III) with the extractant and DTPA solution either one of which was irradiated with60Co γ-rays or the organic—aqueous mixed phase irradiated under continuous stirring. The irradiation causes an increase of Df and a decrease of the Nd/Am separation factor β, to an especially large extent in the mixed phase system. These effects are due firstly to the radiolytic decomposition of DTPA and secondarily to the formation of MEHPA. The replacement of nitrate with lactate stops the degradation of DTPA and DEHPA resulting in the retardation of increase of Df and a decrease of separation factor. The DEHPA-DTPA-lactic acid system is concluded to sustain absorption of radiation at an absorbed dose up to 200 Wh·I−1 in the partitioning of transplutonium elements in HLW.

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Japanese iron artifacts contain a small amount of charcoal which was used in manufacturing. We developed a wet method of carbon extraction from the iron samples for AMS radiocarbon dating. The method consists of dissolution of iron with a Cu2+ solution and dissolution of deposited Cu in HCl. High extraction yields (80–90%) and low contamination by modern carbon were achieved by the wet method.

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A highly precise and accurate method for the determination of minor amounts of iron by substoichiometric isotope dilution analysis is described. The constant amount of Fe(III) is substoichiometrically extracted with 2·10−4M oxine in chloroform from the aqueous phase of pH 9.2–10.0 containing 6·10−3M tartrate. The interfering ions such as Mn(II), Co(II), Ni(II), Cu(II), and Zn(II), can be removed by the preliminary extraction of Fe(III) from 7.5M hydrochloric acid solutions into isopropyl ether. The present method has been applied to the determination of iron in biological standard reference materials, i.e., the NBS Spinach (SRM-1570) and the NIES Pepperbush (SRM No. 1), and the results obtained are 548±9 ppm (NBS certified value: 550±20 ppm) and 193±4 ppm, respectively.

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The substoichiometric isotope dilution analysis for manganese(II) in a synergistic extraction system of a chelating agent and a neutral ligand is described. The substoichiometric extarction is based on a substoichiometric amount of 2-thenoyltrifluoroacetone and an excess of 1,10-phenanthroline. The recommended condition and the reproducibility of the present system were examined. The present method was applied for NBS-SRM tomato leaves and NIES-SRM chlorella, and very good results with high accuracy and precision were demonstrated.

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Abstract  

Synergistic effect of neutral bidentate ligands, L, such as 1,10-phenanthroline(phen), 2,9-dimethyl-1,10-phenanthroline(dmp), and 2,2-bipyridine(bpy), and of neutral unidentate ligands TBP and TOPO have been studied in the extraction of Mn(II) labeled with54Mn, using 2-thenoyl-trifluoroacetone(HTTA) in various organic solvents. The following factors play an important role in the synergistic extraction involving bidentate ligands; two-phase partition of bidentate ligands, their protonation and complex formation with Mn(II) in the aqueous phase. The mixed ligand complex, Mn(TTA)2L, is formed in all bidentate ligand systems. The adduct formation constant ( S,1) decreases in the following order; phen (lg S,1=12.64) > dmp(11.32)> · bpy(8.54) in the cyclohexane system. This order is ascribed to the bacisity and the steric effect of the bidentate ligands. Organic solvents influence both the adduct formation and the partition of the ligands, and S,1 decreases in the order cyclohexane>carbon tetrachloride>chlorobenzen = benzene>chloroform.

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In order to clarify the influence of radiation degradation of DEHPA upon the extraction of lanthanides, the extraction of neodymium(III) was studied using DEHPA, MEHPA, 2-ethylhexanol and γ-ray irradiated DEHPA. The most significant effect of DEHPA radiolysis on the extraction was found to be the enhacement of extraction capability mainly due to the primary radiolysis product MEHPA. 2-Ethylhexanol, another radiolysis product, showed a depressant effect on DEHPA-Nd(III) extraction. However, the mixture of MEHPA and 2-ethylhexanol improved the extraction. The mixed solvent DEHPA-MEHPA was found to be more effective than the individual components for lanthanide extraction.

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