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  • Author or Editor: G. Jia x
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ERECTA is an ancient family of leucine-rich repeat receptor-like kinases (RLKs) that coordinate growth and development of plant. TaERECTA, one copy of the ERECTA homologs in wheat, was isolated from bread wheat Chinese Spring. The Ser/Thr kinase of TaERECTA was expressed in E. coli after IPTG induction and confirmed by immunoblot. TaERECTA showed higher expression in younger organs with rapid development, as well as great expression in younger spikes at booting stage. Under exogenous application of gibberellin (GA3) and abscisic acid (ABA), and Mg2+ stress, the expression of TaERECTA was largely suppressed, whereas under exogenous application of indole acetic acid (IAA) and brassinolide (BR), and dehydration stress, its expression was initially suppressed and then up-regulated. Natural variation was apparent in the relative expression of TaERECTA among 9 different bread wheat lines, and its expression level was negatively correlated with the stomatal density. These results suggested that TaERECTA could be exploitable for manipulating agronomical traits important through regulating stomata density, with potential implication for bread wheat improvement.

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A sensitive and accurate method for determination of radium isotopes in soil samples by α-spectrometry has been developed 225Ra, which is in equilibrium with its mother 229Th, was used as a yield tracer. Radium in soil samples was fused together with Na2CO3 and Na2O2 at 600 °C, leached with HNO3, HCl and HF, preconcentrated by coprecipitation with BaSO4, separated from uranium, thorium and iron using a Microthene-TOPO chromatographic column, isolated from barium in a cation-exchange resin column using 0.05M 1,2-cyclohexylene-dinitrilo-tetraacetic acid monohydrate as an eluant, electrodeposited on a stainless steel disc, and counted by α-spectrometry. The detection limit of the method is 0.43 Bq·kg−1 for 226Ra, 228Ra and 224Ra if 0.50 g of soil sample are analyzed. The method was checked with two certified reference materials supplied by the IAEA, and reliable results were obtained Fourteen soil samples collected from the refractory industry in Italy were also analyzed. The mean radiochemical yields for radium were 85.7±4.3%, and the obtained radium concentrations in the soil samples were in the range of 8.08–3878 Bq·kg−1 for 226Ra, of 1.60–678 Bq·kg−1 for 228Ra and 1.25–550 Bq·kg−1 for 224Ra, with 228Ra/226Ra and 224Ra/226Ra ratios ranged from 0.159–0.821 and from 0.142 to 0.525, respectively.

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In order to improve the selectivity of the uranium isotopes determination in environmental samples, further studies have been carried out, including (1) interference of 210Po with uranium isotope determination, (2) distribution coefficients of polonium between 5% TOPO in toluene and aqueous hydrochloric and nitric acids, (3) decontamination factor of uranium from polonium of the recommended procedure, and (4) leaching effect comparison of two different leaching procedures in a lichen sample. Based on the new findings, a more accurate extraction chromatographic/ a-spectroscopy method has been developed. For the method's validation, four kinds of reference materials supplied by the IAEA have been tested. It is observed that nearly all the 238U, 234U and 235U concentrations obtained are in good agreement with the recommended or information values, showing that the method can give reliable results. A comparison with existing uranium determination methods has also been made. It is concluded that due to involving preconcentration and chemical separation, the extraction chromatographic/a-spectroscopy method is a more selective, very sensitive and accurate, and low cost method.

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Many lanthanide radionuclides, having various nuclear properties but similar chemical properties, are considered suitable for different radiotherapeutic applications. This paper describes the production of a number of radiolanthanides (e.g.153Sm,166Dy,166Ho,161Tb and177Lu) and the radiotherapy research involving these radionuclides at the University of Missouri Research Reactor Center (MURR).

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Thermal behaviors of two mixed-ligand complexes, [Ni(PMPP-SAL)(Py)3] and [Cu(PMPP-SAL)Py]·MeOH, (PMPP-SAL=1-phenyl-3-methyl-4-(salicylidene hydrazide)-propenylidene-pyrazolone-5, Py=pyridine), were studied by TG-DTG-DTA in dynamic air atmosphere. The complexes show the loss of pyridine molecule is followed by the decomposition of the PMPP-SAL anion and give respective metal oxides as residues. Meanwhile, the Ozawa-Flynn-Wall model-free analyses and multivariate non-linear regressions were applied to perform single and overall steps optimization. Kinetic parameters were given and the most probable mechanism functions were suggested in this study.

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A method for the determination of low-level radium isotopes in mineral and environmental water samples by alpha-spectrometry has been developed. Radium-225, which is in equilibrium with its mother 229Th, was used as a yield tracer. Radium were preconcentrated from water samples by coprecipitation with BaSO4and iron (III) hydroxide at pH 8-9 using ammonia solution, then isolated from uranium, thorium and iron using a Microthene-TOPO chromatography column at 8M HCl, separated from barium in a cation-exchange resin column using 0.05M 1,2-cyclohexylenedinitrilotetraacetic acid monohydrate at pH 8.5 as an eluant, and finally electrodeposited on a stainless steel disc in a medium of 0.17M (NH4)2C2O4at pH 2.6 and current density of 400 mA. cm-2, and counted bya-spectrometry. Optimum experimental conditions for radium separation, purification and electrodeposition have been studied and discussed in the paper. The lower limits of detection of the method are 0.11 mBq. l-1for 226Ra, 228Ra and 224Ra, respectively, if 2 l of water are analyzed. The method has been checked with a certified reference material IAEA-Soil-6 supplied by the International Atomic Energy Agency and reliable results were obtained. Eighteen water samples collected in Italy have been analyzed with the method, the mean radiochemical yields for radium were 86.2±6.5%. The obtained radium concentrations were in the range of 0.50-60.8 mBq. l-1for 226Ra, of 0.10-25.7 mBq. l-1for 228Ra, and of£LLD-7.97 mBq. l-1for 224Ra. The 228Ra/226Ra and 224Ra/226Ra ratios were in the range of 0.189-4.45 and£LLD-0.941, respectively.

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A simple, sensitive and selective method is described for the simultaneous determination of plutonium and americium in lichen and moss samples which can be used as the atmospheric radioactivity bioindicators. Plutonium is separated from a HCl leaching solution by a Microthene-TNOA column; americium is separated by a KL-HDEHP column and purified by PMBP-TOPO extraction. A special attention has been paid to the decontamination of plutonium and americium from210Po. Ten lichen and 12 moss samples from tree trunks have been analyzed: starting from 2 g sample, the average yields and the detection limits were 70.2±12.5% and 28 mBq/kg for plutonium and 70.0±15.1% and 34 mBq/kg for americium. The concentrations (mBq/kg) ranged from 28 to 4960 for239,240Pu, from 28 to 171 for238Pu and from 34 to 1930 for241Am, respectively.

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Polypeptide microspheres containing polycysteine crosslinked with polylysine were prepared and radiolabeled with186Re and188Re. High labeling yields with the microspheres with both186Re and188Re (97%) were obtained, and above 99% retention of radiolabels in water in 24 hours was obtained. Rhenum-186 labeled polycysteine and polylysine microspheres (11 ratio, 20 m as mean diameter) were injected intra-articularly into the rear stifes (knee joints) of normal New Zealand white rabbits. About 87% of injected dose was retained in rabbit stifles and adjacent tissues in 96 hours after injection, while most of the activity lost from the joints was excreted in the urine. Due to its simplicity of preparation and radiolabeling, versatility, and biodegradability, this type of conjugate system may become the therapeutics of choice for radiation synovectomy.

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