气相色谱-串联质谱法同时检测代用茶中的16种农药残留

目的建立气相色谱-串联质谱法同时检测代用茶中16种农药残留的分析方法。方法代用茶样品中的农残经乙腈提取后,用25 mg N-丙基乙二胺(primary secondary amine, PSA)、150 mg MgSO4净化,引入分析保护剂补偿基质效应,用气相色谱-串联质谱法测定其中16种农药残留。结果 16种农药成分在0.005～0.400μg/mL范围内有良好线性关系,相关系数均大于0.98;检出限均在0.003～0.007 mg/kg之间,定量限在0.011～0.022 mg/kg之间;在3个添加水平下(0.04、0.10和0.40 mg/kg)的平均回收率为80.2%～104%,相对标准偏差(n=6)为3.4%～12.4%。结论本方法样品处理简单快速,灵敏度和选择性高,重复性好,适用于代用茶中多种农药残留的同时检测。     

Review of mathematical models for health risk assessment: VII. chemical dose

The health risk assessment of chemical emissions from industrial facilities requires the mathematical modeling of a variety of processes, including transport and fate of chemicals in and between various environmental media, population exposure to these chemicals, their associated doses, and health effects. Several models are presently available to address these different components of the health risk assessment. Existing models were reviewed and recommendations are provided for the selection of models suitable for screening and refined risk assessments. This article reviews mathematical models for estimating chemical dose.     

染料木黄酮对β淀粉样肽介导的脑血管内皮细胞损伤的保护作用研究

目的研究染料木黄酮(Gen)对β淀粉样肽25-35(Aβ25-35)介导的脑血管内皮细胞损伤的调节作用。方法脑血管内皮细胞(b End.3细胞系)传代48 h后,分为4组(对照组、Aβ组、Gen组、Gen+Aβ组)。Gen预处理2 h后,Aβ25-35染毒建立细胞损伤模型;24 h后收集细胞进行指标检测。采用ELISA法检测脑血管内皮细胞8-OHd G水平;酶法试剂盒检测GSH-Px水平;RT-PCR和Western blot法检测Bcl-2、Bax基因和蛋白表达的改变。结果与对照组比较,Aβ组8-OHd G水平明显升高,GSH-Px活性明显下降,且差异均有统计学意义(P0.05);与Aβ组比较,Gen组和Gen+Aβ组8-OHd G水平明显下降,GSH-Px活性明显升高,且差异均有统计学意义(P0.05);同时,Aβ组Bcl-2基因和蛋白表达水平较对照组明显下调,Bax基因和蛋白表达水平明显上调,且差异均有统计学意义(P0.05);与Aβ组比较,Gen+Aβ组和Gen组Bcl-2基因和蛋白表达水平明显上调,Bax基因和蛋白表达水平明显下调,且差异均有统计学意义(P0.05)。结论 Gen可能通过拮抗Aβ25-35介导的脑血管内皮细胞氧化损伤,进而发挥对脑血管的保护作用。     

A controlled approach for synthesizing CdTe quantum dots polyamidoamine nanocomposites

We develop a controllable approach to prepare ordered–CdTe quantum dots (QDs) polyamidoamine (PAMAM) nanocomposites (NCPs) by self-assembly growth of simple CdTe– PAMAM in aqueous solution. The sphere and network CdTe NCPs were obtained at pH 4.7 for growing 15 h and 79 h respectively. As the NCPs ceased growing over pH 8 immediately, we can conveniently control their size and morphology by adjusting pH of the solution to tune the growth time. The morphology change of CdTe-PAMAM nanocomposites was characterized by TEM images. The fluorescent intensity and photostability of ordered–CdTe–PAMAM have been improved significantly.     

Evolution of oxide scales on an ODS FeAl intermetallic alloy during high temperature exposure in air

The oxide dispersion strengthened FeAl Grade 3 intermetallic alloy have been shown to develop a structured oxide scale upon isothermal oxidation between 850 and 950 °C for 24 h. Transmission electron microscopy studies have revealed a top nanoequiaxed alumina, alumina and Fe–Al spinel at the outer, central and internal layers, respectively. At 1000 °C, the spinel phase no longer forms but a columnar alumina layer topped by a nanoequiaxed structure. The role of yttria is negligible at lower temperatures whereas some segregation at the scale/substrate interface and precipitation of YAlO₃ is observed at 1000 °C.     

Polybrominated diphenyl ethers (PBDEs) and indicator polychlorinated biphenyls (PCBs) in various marine fish from Zhoushan fishery,China

Levels of polybrominated diphenyl ethers (PBDEs) and indicator polychlorinated biphenyls (indicator-PCBs) were measured in thirty-two commonly consumed marine fish species from Zhoushan Fishery, China. Factors effecting the accumulation of the compounds in sea fish were discussed, as well as the associated health risk via fish consumption. Levels and congener profiles of these contaminants varied by fish type. Due to the different accumulation influenced by fat content, feed habits and living zone in the sea area, levels of total nine PBDEs ranged from 0.0085 ng/g wet weight (Pagrosomus major) to 1.6819 ng/g wet weight (Bullet mackerel). The corresponding values for six indicator-PCBs ranged from 0.0124 ng/g wet weight (Navodon septentrionalis) to 3.8244 ng/g wet weight (Bullet mackerel). Total PBDEs and total indicator-PCBs intakes for Chinese population were estimated according to the contaminant level in each fish species and mean fish consumption in China, using an average body weight as 60 kg for the general population. The estimated intake of total PBDEs and total indicator-PCBs ranged from 0.007 ng/kg bw/day (Pagrosomus major) to 1.402 ng/kg bw/day (B. mackerel) and 0.010 ng/kg bw/day (N. septentrionalis) to 3.187 ng/kg bw/day (B. mackerel), respectively. The evaluated health risk associated with PBDEs intakes and indicator-PCBs intakes via consumption of all the fish species are relatively low for Chinese resident.     

富含黄酮类物质果蔬汁对大鼠肝脏中氧化损伤相关Ⅱ相代谢酶基因mRNA表达的影响

探讨富含黄酮类物质的果蔬汁对大鼠肝脏内氧化损伤相关Ⅱ相代谢酶基因表达的影响。方法 SPF级雄性成年大鼠54只按体重随机分为对照组、低剂量果蔬汁干预组和高剂量果蔬汁干预组,对照组每日给予生理盐水灌胃、干预组给予低剂量和高剂量果蔬汁灌胃。干预5周后,腹主动脉采血用于生化指标检测;取肝脏组织检测基因表达情况。RT-PCR方法检测肝脏中氧化损伤相关Ⅱ相代谢酶mRNA的表达情况;试剂盒法测定血清总抗氧化能力(T-AOC)、丙二醛(MDA)、谷胱甘肽(GSH)含量。结果 与对照组相比,低、高剂量果蔬汁饮食干预组大鼠的血清抗氧化能力增强,同时上调肝脏中药物代谢Ⅱ相酶人醌NADH脱氢酶(NQO1)和谷氨酰-半胱氨酸连接酶催化亚基(GCLC)mRNA的表达(P＜0.05),但对GSTP1、GCLM、GSTM2、GSTA2Ⅱ相代谢酶基因mRNA表达无影响。结论 富含黄酮类物质果蔬汁可以增强大鼠血清抗氧化能力,同时诱导肝脏中抗氧化Ⅱ相代谢酶NQO1及GCLC基因mRNA的表达。