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121.
An accurate and rapid LC-ESI-MS/MS analytical method was developed and validated for the simultaneous determination of aflatoxin B1, B2, G1 and G2 in lotus seeds. The samples were firstly extracted with methanol-water solution (80:20, v/v), and then cleaned up by immunoaffinity columns. The mass spectrometer was operated in the positive ionization electrospray (ESI+) mode using multiple reaction monitoring (MRM) for analysis of four aflatoxins. The transitions of m/z 313 → 285 (AFB1, CE 33 eV), m/z 315 → 259 (AFB2, CE 37 eV), m/z 329 → 243 (AFG1, CE 37 eV) and m/z 331 → 257 (AFG2, CE 37 eV) were used to quantify these four aflatoxins, respectively. The limits of detection (LODs) of aflatoxin B1, B2, G1 and G2 were 0.007, 0.005, 0.003 and 0.005 μg kg?1 based on a signal-to-noise ratio of 3:1, respectively. The limits of quantification (LOQs) of aflatoxin B1, B2, G1 and G2 were 0.02, 0.015, 0.01 and 0.015 μg kg?1 based on a signal-to-noise ratio of 10:1, respectively. Recoveries for samples of spiked lotus seeds were all above 66% with relative standard deviation all below 15% for all compounds. Nineteen out of twenty batches of lotus seeds collected from different drug stores or markets in China were found to be contaminated with aflatoxins at different levels ranging from 0.02 to 688.4 μg kg?1. 相似文献
122.
Xiaolong Tang Shuyu Cai Rongbo Zhang Peng Liu Hongbo Chen Yi Zheng Leilei Sun 《Nanoscale research letters》2013,8(1):420
A system of novel nanoparticles of star-shaped cholic acid-core polylactide-d-α-tocopheryl polyethylene glycol 1000 succinate (CA-PLA-TPGS) block copolymer was developed for paclitaxel delivery for breast cancer treatment, which demonstrated superior in vitro and in vivo performance in comparison with paclitaxel-loaded poly(d,l-lactide-co-glycolide) (PLGA) nanoparticles and linear PLA-TPGS nanoparticles. The paclitaxel- or couramin 6-loaded nanoparticles were fabricated by a modified nanoprecipitation method and then characterized in terms of size, surface charge, surface morphology, drug encapsulation efficiency, and in vitro drug release. The CA-PLA-TPGS nanoparticles were found to be spherical in shape with an average size of around 120 nm. The nanoparticles were found to be stable, showing no change in the particle size and surface charge during 90-day storage of the aqueous solution. The release profiles of the paclitaxel-loaded nanoparticles exhibited typically biphasic release patterns. The results also showed that the CA-PLA-TPGS nanoparticles have higher antitumor efficacy than the PLA-TPGS nanoparticles and PLGA nanoparticles in vitro and in vivo. In conclusion, such nanoparticles of star-shaped cholic acid-core PLA-TPGS block copolymer could be considered as a potentially promising and effective strategy for breast cancer treatment. 相似文献
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A family of discontinuous Galerkin (DG) methods are formulated and applied to chemical engineering problems. They are the four primal discontinuous Galerkin schemes for space discretization: symmetric interior penalty Galerkin, Oden-Babu?ka-Baumann DG formulation, nonsymmetric interior penalty Galerkin, and incomplete interior penalty Galerkin. Numerical examples of DG to solve typical chemical engineering problems, including a diffusion-convection-reaction system in a catalytic particle, a problem of heat transfer in a fixed bed, and flow and contaminant transport simulations in porous media, are presented. This article highlights the substantial advantages of DG on adaptive mesh modification over traditional methods. In particular, we propose and investigate the dynamic mesh modification strategy for DG guided by mathematically sound a posteriori error estimators. 相似文献
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文23气田低伤害酸化工艺技术研究与应用 总被引:2,自引:0,他引:2
文23低渗气藏具有埋藏深、物性差等特点,通过常规酸化对文23气田储层伤害的分析,研制出了气井低伤害酸液,筛选出防水锁剂JIX-Ⅱ、酸化缓蚀剂HSJ-Ⅱ等低伤害酸化添加剂,酸体系表面张力≤23m·N/m,界面张力≤0.5m-N/m,腐蚀速度〈5g/m^2·h(90℃)。室内岩心流动实验表明酸液具有较高的储层渗透率改善效果及较低的储层岩心伤害率。低伤害酸液体系与新型撬装气举残酸反排工艺的应用使得储层残酸、井筒积液反排彻底,提高了气井酸化效果。经过在文23气田15口井次的现场应用,平均单井日增气4.5×10^3m^3,平均有效期132d。表明该气井低伤害酸化工艺技术对于文23气田低渗气藏酸化改造具有良好的增产效果和广阔的推广应用前景。 相似文献
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随着经济的高速发展,多普勒激光测量仪在轧钢厂逐渐应用。激光测速仪可安装在钢坯的上方、下方或两侧,其采用非接触传感器测量钢坯速度和长度,灵敏度高,解决了钢坯长度不准的问题。 相似文献