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31.
Dietary exposure of Thais to pesticides during 1989-1996 总被引:1,自引:0,他引:1
Vongbuddhapitak A Atisook K Thoophom G Sungwaranond B Lertreungdej Y Suntudrob J Kaewklapanyachareon L 《Journal of AOAC International》2002,85(1):134-140
To monitor the exposure of the Thai to pesticide residues in foods, the intake of pesticides based on the total diet approach has been studied in Thailand continually since 1989. Food items were chosen and their proportions of daily consumption were calculated from the national food consumption survey conducted by the Department of Health in 1986. Seventy-seven items of food including drinking water were classified into 12 groups according to their sources of contamination and the analytical methods used. Shopping lists and standard procedures for collecting samples and cooking were developed. Twelve food composites from each of the 4 regions were analyzed for nearly 100 pesticides. All analyses used multiresidue analytical methods, and the total daily dietary intakes of pesticide residues were estimated from the average amount of food consumed by Thais. Among 24 pesticides found in the 8 year study, DDT, dimethoate, methamidophos, and parathion methyl were found every year. However, dietary intakes of all pesticides were far below the established acceptable daily intake. In 1999, the study methodology was redesigned to accommodate the new national food consumption survey data. 相似文献
32.
Dr. M. John Plater Amara Darr Catriona Crawford Craig Murray Struan Simpson Prof. William T. A. Harrison Prof. Juan M. Clemente-Juan 《ChemistryOpen》2019,8(9):1204-1208
The synthesis of a Cu4(OH)4 cube which is coordinated by four molecules of the dipyridyl ligand 1,6-[di(pyridin-4-yl)hex-3-ene] is reported. This compound has a trans double bond which restricts the conformational freedom of the ligand and favours coordination within a unique copper cube. The structure was solved by an X-Ray single crystal structure determination and low temperature magnetic susceptibility measurements examined its magnetic properties. The cube classification corresponds to the type I classification of Mergehenn and Haase and the short/long distribution of Cu ⋅⋅⋅ Cu separations in the cube as defined by Ruiz. The magnetic susceptibility measurements show paramagnetic behaviour down to 50 K but below this the copper cube shows weak ferromagnetic exchange interactions. The low temperature magnetic susceptibility characteristics are examined in detail then modelled and compared to other similar Cu4O4 copper cubes. 相似文献
33.
In the paper, we study the problem on the number of zeros of eigenfunctions of the fourth-order boundary-value problem with
spectral and physical parameters in the boundary conditions. We show that the number of zeros of the eigenfunctions corresponding
to eigenvalues of positive type behaves in a usual way (it is equal to the serial number of an eigenvalue increased by 1),
but, however, the number of zeros of the eigenfunction corresponding to an eigenvalue of negative type can be arbitrary. In
the case of a sufficient smoothness of coefficients of the differential expression, we write the asymptotics in the physical
parameter for such a number.
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Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 12, No. 4, pp. 41–52, 2006. 相似文献
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37.
Mourad Hidouri Besma Lajmi Mongi Ben Amara 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):i147-i148
Crystals of sodium zinc diiron(III) triphosphate, NaZnFe2(PO4)3, have been synthesized and structurally characterized by single‐crystal X‐ray diffraction. The compound features a new structural type built up from ZnO6 octahedra, FeO6 octahedra and FeO4 tetrahedra, linked together via the corners and edges of PO4 tetrahedra to form a three‐dimensional framework, with tunnels running along [100]. Within these tunnels, Na+ cations occupy a highly distorted cubic site. 相似文献
38.
C. Parent M.Ben Amara P. Bochu G. Le Flem P. Hagenmuller 《Journal of solid state chemistry》1984,53(2):168-173
The conditions of a Ce3+ → Tb3+ energy transfer have been analyzed in the Na2+x+yCa2(1?x?y) CexTby(PO4)2 orthophosphates. Terbium green emission through uv cerium excitation is characterized by a very low yield. This result is the consequence of a sodium-rare-earth short range ordering even at low rare-earth concentrations and of lack of rigidity in the anionic sublattice. 相似文献
39.
We study the spectral probleml(u)=−u″+q(x)u(x)=λu(x),u′(0)=0, u′(π)=mλu(π), where λ andm are a spectral and a physical parameter. Form<0, we associate with the problem a self-adjoint operator in Pontryagin space II1. Using this fact and developing analytic methods of the theory of Sturm-Liouville operators, we study the dynamics of eigenvalues
and eigenfunctions of the problems asm→−0.
Translated fromMatematicheskie Zametki, Vol. 66, No. 2, pp. 163–172, August, 1999. 相似文献