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  • Author or Editor: S. Liu x
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Abstract  

Radiobrominations of cetyl bromide with82Br in several organic media such as DMF, 18-crown-6, DMSO, pyridine and n-butanol were achieved and a comparison was made as to the labelling rates. The rate order was found as follows: DMF>18-crown-6>DMSO>pyridine } n-butanol which was attributed to increased anion /i.e., the nucleophilic bromide ion,82Br/ solvation. Labelling in pyridine or alcohol was found to be too slow to meet practical needs. A suitable crown ether such as 18-crown-6 was found to be favourable for rapid radiobromination. However, it was discovered unexpectedly that dimethylformamide /DMF/ was superior to 18-crown-6. We therefore recommend DMF as an alternative reaction medium for fast radiobromination considering that this solvent is inexpensive and readily available.

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he purpose of this paper is to give the direct and inverse theorem for pointwise approximation by Bernstein type operators.

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We establish a sharp estimate for some multilinear operator related to Bochner--Riesz operator. As an application, we obtain the weighted norm inequality and L log L type estimate for the multilinear operator.

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Abstract  

Sixteen minor and trace element contents of diet samples collected from the Pratas islanders were determined using instrumental neutron activation analysis. Samples were prepared by the duplicate portion technique, collecting during a 3-day period in winter. Dry weight elemental concentrations and daily dietary intake by islanders are compared with those taken by urban population living in Taiwan, resulting in higher intake of most elements. In addition, concentration of natural radionuclides and artificial fallout in daily diet were determined by means of -spectroscopy; the annual intake of radioactivity was evaluated and compared with those in population of neighboring Taiwan and South China. Features of the elemental concentration and radioactive concentration in the diet are discussed.

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Abstract  

Labeling of antibodies, immunoglobulin G (IgG), with a multitracer was investigated with the aim of its utilization in the preparation of radiopharmaceuticals. The labeling procedure consists of two steps: conjugation of diethylenetriaminepentaacetic acid (DTPA) cyclic dianhydride with IgG and subsequent labeling with the multitracer.

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Abstract  

Radioisotopes of 37 elements were isolated from a gold target irradiated with an energetic12C beam and were used as a multitracer to establish procedures for separating themselves into groups of carrier-, salt-and organic matter-free tracers. Solvent extraction with HDEHP and ethyl methyl ketone along with cation exchange yielded group tracers ready for application to chemical and biological studies.

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Abstract  

The migration of 237Np in an undisturbed Chinese loess column was investigated by direct γ-ray method. The column was taken from a field test site and installed in a laboratory simulation hall. Radionuclide 237Np in the form of neptunium nitrate, mixed with quartz, was introduced into the column and covered with loess. Artificial rainfall was applied to the column for about 3 years and, the counting rates of 237Np in the column from 56 to 616 days at different vertical positions were detected with a γ-ray detection system. Based on the counting rates of 237Np in the simulation column at different vertical positions and the distance from the source layer, the relationship of the mass center of 237Np in the column at different experimental periods to the experimental time was established, C m = 0.36 log(t)-2.75. Here C m is the mass center of 237Np in the column, cm, and t is the experimental time in days. Based on this relationship, the mass center of 237Np for the 1,073-day experiment was predicted and compared to that obtained with the final destructive method. The good agreement between the prediction and the experimental values indicates that the direct γ-ray method could be used to predict the migration of strongly adsorbed radionuclides such as 237Np in environmental media with the help of laboratory simulation columns.

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Abstract  

The application of a microcalorimetric method to the study of extremophiles is described briefly. Using the LKB 2277 Bioactivity Monitor, the growth thermogenic curves of three strains of Halobacterium halobium were determined at 37C, and compared with the spectrophotometric curves. Then the suitable growth thermokinetic equation was established based on the characteristics of growth thermogenic curves. By using cycle-flow method, all of the growth thermogenic curves of H. halobium strains displayed a brief lag phase before the onset of exponential growth when they were cultured in Halo-2 medium.

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Abstract  

The crystal C81H78N12O6Cd3 was synthesized and its structure was determined by single crystal X-ray diffraction method. The complex crystallizes in the monoclinic system space group P21/n with cell parameters, a=15.959(4) , b=26.222(3) , c=25.907(6) , β=101.60(2). The non-isothermal kinetics of the crystal was studied by use of non-isothermal TG and DTG curves. The kinetic parameters were analyzed by means of integral and differential methods, and mechanism functions of the thermal decomposition reaction for its second step were proposed. The kinetic equation of thermal decomposition is expressed as: dα/dt=Aexp(-E/RT)1.5(1-α)4/3[1/(1-α)1/3-1]−1. The average values of E(kJ mol−1) and lnA/s−1 are 339.25, 43.95, respectively.

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Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most serious diseases of wheat ( Triticum aestivum L.) worldwide. Of 94 Triticum durum/Aegilops tauschii synthetic wheat accessions tested, CI142 (Garza/Boy// Ae. squarrosa 271) was found to be resistant to 6 Chinese PST races. The resistance to stripe rust in CI142 was proven to be controlled by a single dominant gene, tentatively designated YrC142 . Gene postulation showed that the pathogenic specificity of CI142 is different from 21 other lines possessing known resistance genes, such as Yr10, Yr15, Yr24 , and Yr26 , located on chromosome 1B. Bulked segregant analysis (BSA) and F 2 segregation analysis of the CI142/Mingxian 169 cross were used to analyse the SSR markers linked to YrC142 . Five SSR markers were found to be closely associated with YrC142 in the order Xwmc419-YrC142-Xgwm273, Xbarc187-Xgwm18-Xwmc626 , in which the relative genetic distances of these SSR loci to the gene YrC142 were 5.4, 0.8, 0.8, 1.0, and 2.4 cM, respectively. Two SSR markers ( Xgwm273 −162 and Xgwm18 −168 ) distinguished YrC142 from Yr10, Yr15, Yr24 , and Yr26 , suggesting that these 2 SSR markers may be used as diagnostic ones for the gene in a wheat breeding program against stripe rust. Based on these findings, YrC142 is most likely a new gene or a new allele at the Yr26 locus, which provides an opportunity to diversify stripe rust-resistant resources for wheat breeding programs.

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