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  • Author or Editor: J. Zheng x
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Abstract  

For the determination of arsenic compounds in terrestrial plant samples, a crucial step is the efficient extraction of arsenic from the solid plant matrix. However, the use of methanol-water extraction often resulted in low extraction efficiencies of less than 50%. In this study, eight solid-liquid extraction procedures (mainly based on mechanical mixing and sonication) were evaluated for the recovery of arsenic species from a submerged freshwater plant, coontail (Ceratophyllum demersum), collected in Moira River, Ontario, Canada. Speciation of As in the extracts was carried out with both anion-, and cation-exchange HPLC with sector-field inductively coupled plasma mass spectrometric (SF-ICP-MS) detection. The results obtained depended critically on the extraction solvents used in different extraction procedures. Extraction with methanol-water led only to 9%–44% recoveries of As. A high extraction yield (approximately 82%) was obtained by water extraction. Alkaline hydrolysis also resulted in high extraction efficiencies (86%–98%), but severe oxidation of As(III) to As(V) was observed. A protease enzymatic extraction led to a recovery of 48%. Approximately 0.5% of the total As in the plant sample was lipid-soluble. It was found that the extraction of inorganic arsenic species was suppressed by the presence of methanol in the extraction solvents, while high content of methanol in the extraction solvents was effective for the extraction of organic arsenic species. Therefore, it is recommended to perform the extraction both with water alone and with methanol-water (9+1, v/v), in order to obtain the complete As species profile in terrestrial plants.

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Studies on the environmental behavior of plutonium in the marine environment require an analytical method with high sensitivity and capability to provide the isotopic composition of Pu in marine samples. In this work, as part of our on-going project on Pu environmental behavior in the Pacific Ocean, a sector field ICP-MS method combined with an off-line anion-exchange chromatography system was optimized for the determination of Pu and its atomic ratio of 240Pu/239Pu in sediment core samples. Using a conical concentric nebulizer and 150-second counting time, we were able to lower the detection limit of Pu down to 0.35 fg. The mass discrimination effect was evaluated using a mixed Pu isotope standard solution with certified a 240Pu/239Pu isotope ratio (NBS-947). The overall performance of the analytical method was validated by the determination of Pu and its isotope composition in an ocean sediment reference material (IAEA-368). Both the 239+240Pu activity and 240Pu/239Pu atomic ratio were found to be in good agreement with the certified and/or literature values. As an important application, we employed the analytical method to investigate the vertical profiles of 239+240Pu activity and 240Pu/239Pu atomic ratio in sediment cores in the Sea of Okhotsk and the NW Pacific. It was found that the Bikini close-in fallout Pu could be transported as far as the Sea of Okhotsk. The results provided evidence to support our hypothesis on the oceanic current transportation of Bikini close-in fallout Pu in the NW Pacific and its marginal seas.

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Fructose-bisphosphate aldolase (FBA, EC 4.1.2.13) catalyzes an aldol cleavage of fructose-1, 6-bisphosphate to dihydroxyacetone-phosphate and glyceraldehyde 3-phosphate and a reversible aldol condensation. Three candidate genes with 1077bp coding for fructose-bisphosphate aldolase were cloned and sequenced in wheat, barley and rye. These genes could encode 358 amino acid residues. Sequence analysis indicated that wheat, barley and rye FBA genes were conserved with high identity (94.13%), while maize sequence had a 9bp deletion near the 3’ terminal. According to the alignment of 75 amino acid sequences, conserved domains of the FBAs were detected. These conserved domains might be the important functional sites of the FBAs. The cytoplasmic FBAs of wheat, barley and rye were clustered together, and the cluster was close to maize and rice FBAs. Nine peptides of the FBAs and the last amino acid Tyr (necessary for preference for fructose 1,6-bisphosphate over fructose 1-phosphate) were most conserved in plants, animals and algae. Current findings suggested that the FBAs could be divided into three main subgroups: plant cytoplasmic FBA, plant chloroplastic FBA and animal FBA. These results also indicated that the active and binding sites of FBAs had rare variations during the long-term evolution.

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Summary  

From the viewpoint of environmental radioactivity monitoring, the determination of uranium and its isotope ratio is important for identifying and assessing the environmental impact of any unexpected release from nuclear facilities. In this work, a survey was conducted to determine 238U concentrations and 235U/238U atom ratios in coastal waters off Rokkasho Village, Aomori, Japan, where several uranium-related nuclear facilities have been operating since 1992, and a newly constructed nuclear fuel reprocessing plant is scheduled to be commissioned in 2006. Seawater samples were analyzed directly after a 10-fold dilution using isotope dilution sector-field ICP-MS. Based on the results, we concluded that there is no observable uranium contamination in the investigated sites. In addition, for the first time, a correlation between uranium concentration and salinity was established in coastal waters using the SF-ICP-MS technique.

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Summary

A preparative high-speed countercurrent chromatograph (HSCCC) method for the isolation and purification of C6-C2 natural alcohol and benzyl ethanol from Forsythia suspensa was successfully established. Cornoside, forsythenside F, forsythiaside, and acteoside were rapidly obtained for the first time by HSCCC with a two-phase solvent system ethyl acetate-n-butanol-methanol-water (5:1:0.5:5, υ/υ) in one-step separation. The purities of them were all above 97% as determined by high-performance liquid chromatography, and the combination of ESI-MS and NMR analysis confirmed the chemical structures of the four compounds.

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The introgressed alien chromosome in BC 10 F 5 progeny of the cross between common wheat ( Triticum aestivum L.) and Agropyron elongatum (Host) (2n=7X=70) [syn. Thinopyrum ponticum (Popd.) Barkworth & D.R. Dewey] was determined by genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), using genomic DNA from A. elongatum as a probe in GISH and repeat sequence pAs1, pSc119.2 as probes in FISH, and molecular marker techniques. The results revealed that the line was a chromosome additional line in which a pair of the chromosomes added was composed of chromosome segment from E-genome of A. elongatum and short arm of 5B of common wheat cultivar Gao 38 identified by E-genome-specific primers. Powdery mildew test showed the line was highly resistant to powdery mildew as its A. elongatum parent and this indicated that the gene of resistant to powdery mildew might come from A. elongatum and localized on E-genome.

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The aim of this study was to investigate postprandial effects of two Chinese liquors on s elected cardiovascular disease risk factors in humans. Sixteen healthy men were randomized into three groups in a three-way crossover study: tea-flavor liquor (TFL), traditional Chinese liquor (TCL) and water control (WC). Every subject consumed 60 mL of either liquor (45% (v/v) ethanol) or water together with a high-fat meal, respectively. Compared with baseline, serum uric acid was significantly increased in TFL group (0.5-hour: P = 0.012; 1-hour: P = 0.001; 2-hour: P = 0.008) and it was significantly decreased in WC group (1-hour: P = 0.001; 2-hour: P = 0.001; 4-hour: P < 0.001), while uric acid was non-significantly increased in the TCL group. High-sensitive C-reactive protein (hs-CRP) was significantly increased in the TCL (P = 0.014) and WC (P = 0.008) groups at postprandial 4 hours compared with baseline. There was no significant difference between groups during the postprandial period for these two parameters or other biochemical parameters. In conclusion, both liquors increased postprandial uric acid, and no significant difference was observed for the effects of TFL and TCL on the measured biochemical parameters.

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Abstract  

57Fe Mössbauer spectroscopy has been applied to the ultramafic rocks collected from the Jinchuan nickel deposit in China to elucidate their mineralization process. Their Mössbauer spectra consisted of two sextets ascribable to magnetite, two doublets ascribable to Fe2+ and Fe3+ in chromite, and one doublet ascribable to olivine. The closest sample to the ore body did not contain chromite and contained a doublet ascribable to pyrite and a sextet ascribable to pyrrhotite. The valence and site distribution of iron species suggested low oxygen fugacity for the formation of the Jinchuan nickel deposit.

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Abstract  

To investigate the formation of mobile organic plutonium, we analyzed the plutonium contents of the fulvic (FA) and humic (HA) acids from the soil samples obtained at Nishiyama, Nagasaki, Japan. The percentages of the plutonium bound strongly to HA and to FA vs. the total plutonium in the soil were 5–10% and 1%, respectively, at the depth of 0–0.1 m, much higher values than those of137Cs and uranium. After being weathered for 51 years under a temperate climate, the initial highfired oxides of fallout plutonium have become as chemically reactive plutonium from nuclear fuel reprocessing plants.

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Abstract  

An analytical method for the determination of 239Pu and 240Pu in marine particle samples by sector field high-resolution ICP-MS was developed. The method was applied for large and small particle samples (particle diameter: >70 μm and 1–70 μm, respectively, collected with a large volume in situ filtration and concentration system at different depths in the water column off Rokkaho, Japan, where the spent nuclear fuel reprocessing plant of Japan Nuclear Fuel Ltd. has started test operation since March 2006.

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