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Summary A method was developed for the separation and quantification of the warfare nerve agent sarin (O-isopropylmethylphosphonoflouridate), its metabolite methylphosphonic acid, the anti nerve agent drug pyridostigmine bromide
(PB;3-dimethylaminocarbonyloxy-N-methyl pyridinium bromide) and its metaboliteN-methyl-3-hydroxypyridinium bromide in rat plasma and urine. The method involved using solid phase extraction and high performance
liquid chromatography (HPLC) with reversed phase C18 column, and UV detection at 280 nm. The compounds were separated using gradient of 1% to 55% acetonitrile in 0.1% triflouroacetic
acid water solution (pH 3.20) at flow rate of 0.9 ml/min in a period of 15 min. The retention times ranged from 4.4–12.1 min.
The limits of detection were 50 ng mL−1 for PB andN-methyl-3-hydroxypyridinium bromide, and 10 μg mL−1 for sarin and methylphosphonic acid, while limits of quantitation were between 100 ng mL−1–12 μg mL−1. Average percentage recovery of five spiked samples from plasma were 84.6±8.4, 86.5±9.0, 76.4±8.5, 81.3±8.2, and from urine
78.5±7.9, 76.4±7.8, 74.4±8.4, 80.6±6.8 for sarin, methylphosphonic acid, pyridostigmine bromide andN-methyl-3-hydroxypyridinium bromide, respectively. This method was applied to analyze the above chemicals and metabolites
following combined administration in rats. 相似文献
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In this study,the three dimensional nanoscale organization in the photoactive layers of poly(3-hexylthiophene) (P3HT) and a methanofullerene derivative (PCBM) is revealed by transmission electron tomography.After annealing treatment,either at elevated temperature or during slow solvent evaporation,nanoscale interpenetrating networks are formed with high crystalline order and favorable concentration gradients of both components through the thickness of the photoactive layer.Such a tailored morphology acco... 相似文献
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Márcio AF Belo-Filho Franklina MB Toledo Bernardo Almada-Lobo 《The Journal of the Operational Research Society》2014,65(11):1735-1747
Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation. 相似文献
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Rare earth element substituted bismuth ferrites (BiFeO3) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi
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La1−x
FeO3 (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of
these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz
to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz).
All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature
shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds
to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity
as well as ε′ are found to be maximum for the sample x=0.2 at room temperature. 相似文献
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CoFe2O4-BaTiO3 composites were prepared using conventional ceramic double sintering process with various compositions. Presence of two phases
in the composites was confirmed using X-ray diffraction. The dc resistivity and thermoemf as a function of temperature in
the temperature range 300 K to 600 K were measured. Variation of dielectric constant (ɛ′) with frequency in the range 100 Hz to 1 MHz and also with temperature at a fixed frequency of 1 kHz was studied. The ac
conductivity was derived from dielectric constant (ɛ′) and loss tangent (tan δ). The nature of conduction is discussed on the basis of small polaron hopping model. The static value of magnetoelectric
conversion factor has been studied as a function of magnetic field. 相似文献
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This study reports a simple and rapid high-performance liquid chromatographic (HPLC) method for the determination of the insecticide diazinon (O,O-diethyl-O[2-isopropyl-6-methylpyridimidinyl] phosphorothioate), its metabolites diazoxon (O,O-diethyl-O-2-isopropyl-6-methylpyridimidinyl phosphate) and 2-isopropyl-6-methyl-4-pyrimidinol, the insecticide chlorpyrifos (O,O-diethyl-O[3,5,6-trichloro-2-pyridinyl] phosphorothioate) and its metabolites chlorpyrifos-oxon (O,O-diethyl-O[3,5,6-trichloro-2-pyridinyl] phosphate), and TCP (3,5,6-trichloro-2-pyridinol) in rat plasma and urine samples. The method is based on using C18 Sep-Pak cartridges for solid-phase extraction and HPLC with a reversed-phase C18 column and programmed UV detection ranging between 254 and 280 nm. The compounds are separated using a gradient of 1% to 80% acetonitrile in water (pH 3.0) at a flow rate ranging between 1 and 1.5 mL/min in a period of 16 min. The limits of detection ranged between 50 and 150 ng/mL, and the limits of quantitation were 100 to 200 ng/mL. The average percentage recovery of five spiked plasma samples were 86.3 +/- 8.6, 77.4 +/- 7.0, 82.1 +/- 8.2, 81.8 +/- 8.7, 73.1 +/- 7.4, and 80.3 +/- 8.0 and from urine were 81.8 +/- 7.6, 76.6 +/- 7.1, 81.5 +/- 7.9, 81.8 +/- 7.1, 73.7 +/- 8.6, and 80.7 +/- 7.7 for diazinon, diazoxon, 2-isopropyl-6-methyl-4-pyrimidinol, chlorpyrifos, chlorpyrifos-oxon, and TCP, respectively. The relationship between the peak area and concentration was linear over a range of 200 to 2,000 ng/mL. This method was applied in order to analyze these chemicals and metabolites following dermal administration in rats. 相似文献