Highly sensitive and selective acetylene sensors based on p-n heterojunction of NiO nanoparticles on flower-like ZnO structures

Acetylene (C₂H₂) gas concentration is a key parameter in transformer monitoring. In current work, the selective acetylene sensors which based on flower-like ZnO structures with NiO nanoparticles were successfully fabricated. The NiO–ZnO composites were synthesized by two-step hydrothermal method. And various of characterization analyses had been applied to the exploration of crystal structure and the p-n heterojunction. According to the systematic gas sensitivity tests, the response of NiO–ZnO (5%) to 50 ppm C₂H₂ was 15.23 at 200 °C whereas the response of pure ZnO was 4.1 in the same condition. In addition, the response value of NiO–ZnO (5%) to 50 ppm C₂H₂ was 3.6 times to 50 ppm H₂. Such a good gas-sensing property of NiO–ZnO composites is due to p-n heterojunction and high catalytic activity of NiO.     

2015年甘肃省白银市食源性腹泻患者诺如病毒检测结果分析

目的 分析2015年甘肃省白银市食源性疾病监测人群诺如病毒检测结果,为科学制定诺如病毒引起食源性疾病的预测、预警及防控提供参考依据。方法 对在医院就诊的344例食源性疾病监测病例进行问卷调查,采集粪便标本,应用实时荧光定量聚合酶链式反应(荧光定量RT-PCR)方法检测诺如病毒GI和GII基因组。结果 2015年白银市报告的344例食源性疾病病例中,检出诺如病毒阳性病例78例,检出率为22.7%(78/344),其中诺如病毒GI基因组阳性5例,GII基因组阳性71例,GI/GII基因组混合感染2例;男性46例,女性32例;阳性患者中年龄最大者83岁,最小者仅3个月,平均年龄为20.3岁。结论 2015年白银市食源性疾病病例中,诺如病毒检出率较高,全年均流行,但流行季节主要在秋冬季,诺如病毒GII基因组为优势组,应加强公众科普宣传教育,提高诺如病毒监测检测能力,完善风险管理措施。     

Hierarchical heterostructure of porous NiO nanosheets on flower-like ZnO assembled by hexagonal nanorods for high-performance gas sensor

A novel hierarchical heterostructure consisting of porous NiO nanosheets and flower-like ZnO assembled by hexagonal nanorods was successfully fabricated by a simple two-step hydrothermal approach. Flower-like ZnO was obtained by the first step hydrothermal method. Through the second step hydrothermal method, porous NiO nanosheets grew on the surface of flower-like ZnO to realize integration of ZnO and NiO, so the p-n heterostructure between ZnO and NiO formed. The samples were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX). Gas sensing test results showed that the sensor based on NiO/ZnO composite exhibited superior sensing properties to acetone. The sensor response to 100 ppm acetone was about 205.14 at the optimum working temperature of 240 °C, and the response and recovery times were about 7 and 20 s, respectively. The enhanced response might be attributed to heterojunction and larger specific surface area provided by attached porous NiO nanosheets. The rapid response and recovery characteristics and improved selectivity attributed to the porous structure and good catalytic actions of NiO nanosheets.     

甘肃不同产地红芪中主要功效成分及有益元素含量的研究

目的比较甘肃省渭源县、漳县、宕昌县、陇西县和武都县等5个产区的红芪样品中主要功效成分总黄酮、总皂甙、总多糖以及9种有益无机元素含量,并分析这些成分与产地之间的关系。方法参照保健食品中功效成分的检测方法对红芪中总黄酮、总皂甙和总多糖的含量进行测定;参考《国家食品污染物和有害因素风险监测工作手册》方法测定红芪中无机元素的含量。结果所采5个产区的红芪样品中总黄酮含量漳县最低(0.935 mg/100 g),渭源县最高(3.115 mg/100 g);总多糖含量宕昌县最低(0.078 mg/g),陇西县最高(0.462 mg/g);总皂甙含量渭源县最低(1.503 mg/100 g),陇西县最高(1.600 mg/100 g)。Ca和Mg的含量均是武都县较高,分别为6960.389 mg/kg和2526.444 mg/kg;比较其余元素发现,Sr在陇西样品中含量较高,均值为82.017 mg/kg,宕昌县样品含量最低,均值为31.500 mg/kg。5个县区之间红芪中总黄酮与总多糖含量含量有统计学差异(P0.05),总皂甙含量无统计学差异(P0.05)。Mg、Mo、Sr在5个县区之间存在统计学差异(P0.05),其他6种元素含量无统计学差异(P0.05)。结论不同产区红芪中总黄酮、总皂甙、总多糖含量和9种有益无机元素含量存在一定的差异,武都县和陇西县样品的质量优于渭源、漳县和宕昌等3个县区,可为红芪资源的进一步开发利用提供参考依据。     

Colorimetric ELISA based on glucose oxidase-regulated the color of acid–base indicator for sensitive detection of aflatoxin B1 in corn samples

This study described a sensitive direct competitive enzyme-linked immunosorbent assay (ELISA) for naked-eye detection of aflatoxin B₁ (AFB₁) by using glucose oxidase (GOx)-regulated bromocresol purple (BCP) color change. GOx was used as an alternative to horseradish peroxidase (HRP) for oxidization of glucose into hydrogen peroxide and gluconic acid. BCP, whose color is significantly sensitive to pH variation, was used as a signal output. Under optimal conditions, the developed method exhibited a considerably high sensitivity for AFB₁ detection with a cutoff limit of 100 pg/mL by the naked eye. The reliability of the developed colorimetric ELISA using naked-eye detection showed no false negative and false positive results among 70 AFB₁ spiked tests. Furthermore, the developed method showed a good linear range of 25–200 pg/mL for AFB₁ quantitative detection with a half-maximal inhibitory concentration at 66.72 pg/mL, which was approximately 10-fold lower than that of conventional HRP-based ELISA (IC₅₀ = 707 pg/mL). The recoveries from four kinds of AFB₁-spiked concentrations in corn extract solutions ranged within 80.56%–108.53%, with a coefficient of variation range of 1.69%–11.86%. These results exhibited good agreement with those of LC–MS/MS method indicating an acceptable accuracy and precision for AFB₁ quantitative detection in actual corn samples. In brief, this study was the first to use a GOx-mediated color change of BCP in immunoassay for naked-eye detection of AFB₁. This study also provided a new method for high-throughput screening detection of other small molecular chemicals using naked eye in resource-constrained countries.     

甘肃省2007-2011年食物中毒流行状况分析

目的：通过对2007-2011年甘肃省食物中毒事件发生状况的分析,探讨食物中毒在甘肃的流行特点,为预防工作提供依据.方法：对甘肃省食物中毒事件报告数据汇总后,利用统计分析方法进行分析处理.结果：甘肃省2007-2011年共发生食物中毒41起,发病1 644人,死亡26人.2009年中毒事件发生起数最多,共13起,近2年有下降趋势.致病因素中微生物引发食物中毒最多,为20起,占总发病人数的74.94％;化学性食物中毒死亡人数最多,占总死亡人数的69.23％.结论：注意饮食卫生、严格食品质量监督、加强安全意识是预防食物中毒和减少死亡率的有效措施.