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应用傅立叶变换近红外光谱(FT-NIR)法和化学分析法测定了400个陈化烤烟烟叶样品的NIR光谱数据和淀粉、多酚、色素含量,采用偏最小二乘法(PLS)法将光谱数据和化学测定值进行拟合,建立了淀粉、多酚、色素的NIR预测模型,进行了模型的内部交叉验证,并用未参与建模的100个样品进行了外部验证.结果表明,淀粉、多酚、色素的NIR预测模型的决定系数(R<'2>)分别为97.64%、86.97%、87.08%,交互校验均方差(RMSECV)分别为0.338、0.283、0.011;模型的预测结果与化学分析法无显著性差异,其RSD均<5%.FT-NIR光谱法可用于批量陈化烟叶样品淀粉、多酚和色素含量的快速检测. 相似文献
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为了快速检测烟草样品中的棕榈酸、亚麻酸及亚油酸含量,采用偏最小二乘法(PLS)将242个烤烟样品的近红外光谱(NIR)及其棕榈酸、亚麻酸、亚油酸含量GC测定值进行拟合,建立了校正模型,考察了光谱预处理方法和光谱谱区范围对模型的影响,并进行了内部交叉验证和模型精度检验及30个测试样品的外部验证。结果表明:①多元散射校正法和7502~5442.3,4427.9~4246.7 cm-1,一阶导数法和7502~5442.3,4601.5~4246.7 cm-1,矢量归一化法和8724.7~5438.5,4427.9~4246.7 cm-1谱区范围分别适合棕榈酸、亚麻酸、亚油酸模型;②3个模型的平均相对精度分别为98.41%,97.84%,98.84%;③3个模型的预测标准偏差均小于5%,且NIR预测值与GC测定值不存在显著性差异。NIR光谱法适合批量烟叶样品中棕榈酸、亚麻酸及亚油酸含量的快速分析。 相似文献
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近红外光谱法快速测定烟草中的绿原酸、新绿原酸和芸香苷 总被引:3,自引:1,他引:2
为了加快烟草中绿原酸、新绿原酸、芸香苷含量的分析速度,采用183个烟草(烤烟)样品绿原酸、新绿原酸、芸香苷含量的高效液相色谱法测定值及其近红外(NIR)光谱,通过多元散射、一阶导数 附加散射校正光谱预处理和偏最小二乘法建立了NIR预测模型,并进行了内部交叉验证和30个烟叶样品的外部预测验证.结果表明:模型的预测值与化学测定值的平均相对偏差分别为0.545%、0.709%、1.954%,RSD各为0.83%、3.18%、1.426%.该方法可用于批量烟草中绿原酸、新绿原酸、芸香苷的快速测定. 相似文献
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声光可调-NIR法预测烟草中的总烟碱、总糖、还原糖和总氮 总被引:6,自引:1,他引:6
采用声光可调(AOTF)-近红外光谱(NIR)仪和Unscrambler化学计量学光谱分析软件,通过旋转扫描的方式测定了534个不同年份、不同地区、不同等级国产烤烟烟叶样品的NIR,采用PLS1建立了测定烟草中总烟碱、总糖、还原糖和总氮的校正模型,并用这些模型对41个未知烤烟烟叶样品进行了预测。结果表明:总烟碱、总糖、还原糖和总氮含量的NIR预测模型的决定系数R2分别为0.9869、0.9851、0.9733和0.9721,预测的平均相对偏差分别为4.21%、2.23%、2.91%和3.60%。AOTF-NIR技术适用于烟草中总烟碱、总糖、还原糖和总氮含量的快速分析。 相似文献
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NIR光谱法快速测定烟草中的草酸、苹果酸和柠檬酸 总被引:5,自引:3,他引:2
为了快速分析烟草中草酸、苹果酸、柠檬酸的含量,采用近红外(NIR)漫反射光谱仪对113个烤烟烟叶样品进行了扫描,GC法测定了其草酸、苹果酸、柠檬酸含量,再采用消除常数法、最大最小归一化法和一阶导数 多元散射校正(MSC)法分别对4246.7~7502.1 cm-1谱区范围内的光谱进行预处理和偏最小二乘法数据拟合,建立了烟草中草酸、苹果酸、柠檬酸的NIR预测模型,并对这些模型进行了外部验证.结果表明,草酸、苹果酸、柠檬酸的预测值与GC测定值的平均相对偏差均在5%以内,RSD均<4%.这些模型可用于批量烟草样品中这3种酸的快速测定. 相似文献
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针对食用油中单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量的快速检测问题,研究探索应用拉曼(Raman)和近红外(NIR)光谱以及特征层数据的融合,结合化学计量学分析,建立食用油MUFA和PUFA含量预测模型。重点研究各种预处理算法对模型预测能力的影响。应用竞争性自适应重加权采样(CARS)提取Raman和NIR光谱的特征波长,应用网格搜索(GS)算法选取支持向量机回归(SVR)模型的参数组合(C,g)值,分别建立基于拉曼和近红外光谱的特征波段的SVR预测模型;建立基于特征层的多源光谱融合的SVR预测模型。试验表明,基于特征层融合建立的Raman-NIR-SVR模型能够实现食用油MUFA和PUFA含量的快速预测,且预测效果更优。其中预测MUFA含量的SG15-ALS-Nor-CARS-MSC-CARSSVR模型的预测集决定系数R2为0.977 3,与单光谱中最优含量预测模型相比增加了2.43%;而预测PUFA含量的MA11-air PLS-Nor-CARS-MSC-CARS-SVR模型的预测集R2为0.993 0,比较最优单光谱数据建立的SVR模型增加了2.57%。结果表明,采用特征层融合方法建立的含量预测模型的综合性能优于基于单光谱数据建立的模型。 相似文献
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Objectives
To analyse trends in smoking prevalence in Ukraine from three surveys conducted in 2001–5, and to explore correlates of observed changes, in order to estimate the stage of tobacco epidemic in Ukraine.Design
Repeated national interview surveys in Ukraine in 2001, 2002 and 2005.Main outcome measure
Prevalence of current smoking among the population aged ⩾15 years.Results
The age‐standardised prevalence of current smoking in Ukrainian men was 54.8% in 2001 and 66.8% in 2005. Among Ukrainian women, prevalence increased from 11.5% in 2001 to 20.0% in 2005. ORs for yearly increase in prevalence were estimated as 1.164 (95% CI 1.111 to 1.220) for men and 1.187 (1.124 to 1.253) for women, which implies that, on average, 3–4% of men and 1.5–2% of women living in Ukraine join the smoking population each year.Conclusions
In Ukraine, smoking prevalence is increasing in most population groups. Among men, the medium deprivation group with secondary education has the highest smoking prevalence. Among women, while the most educated, young and those living in larger cities are the leading group for tobacco use, other groups are also increasing their tobacco use. Tobacco promotion efforts appear to have been significantly more effective in Ukraine than smoking control efforts. The decrease in real cigarette prices in Ukraine in 2001–5 could be the main factor explaining the recent growth in smoking prevalence.Ukraine is a large eastern European country with high smoking prevalence. Tobacco products are widely available at very low prices, and the transnational tobacco industry is extremely successful in promoting its products and lobbying for its interests in the legislative field. Advocacy of tobacco control has only recently achieved some success in the legislative field, with the first tobacco control law being adopted in late 2005. Ukraine ratified the Framework Convention on Tobacco Control in 2006, but there is still much cause for concern regarding the enforcement and effectiveness of the adopted legislative measures. Unfortunately, the government is not yet involved in nationwide surveillance of the tobacco problem, and the available data have mostly been gathered with funding from foreign donors. Several attempts have been made to measure the extent of the tobacco epidemic in the countries of the former Soviet Union (FSU).1,2,3,4,5,6,7 Most of these studies have shown rather high smoking prevalence among men (50–70%) and comparatively low prevalence among women (5–20%). Most countries in the FSU have similar smoking rates, while certain trends are shown to be related to the differences in how the transnational tobacco industry succeeds in every national tobacco market.6 Unfortunately, few studies have been published showing trends in smoking prevalence in the FSU.7 In Ukraine, two studies3,4 provided point estimates of smoking prevalence.The aim of this study was to analyse trends in smoking prevalence in Ukraine, on the basis of three surveys conducted in 2001–5, and to explore correlates of observed changes in order to estimate the stage of the tobacco epidemic in Ukraine. 相似文献15.
了解河南省部分食品中重金属污染的现状。方法 在河南省18个省辖市采集8大类3 657份食品样品,按照国家标准检测食品中铅、镉和汞的含量,检测结果按照GB 2762—2012《食品安全国家标准食品中污染物限量》进行评价。结果 河南省部分食品中铅含量的平均值为0.34 mg/kg,总体超标率为8.8%(320/3 656),其中粮食、肉类和蔬菜中超标率较高,分别为17.2%(95/552)、14.5%(85/587)和10.7%(57/534);部分食品中镉含量的平均值为0.054 mg/kg,总体超标率为3.9%(143/3 657),其中食用菌和蛋类中超标率较高,分别为9.6%(49/508)和8.1%(42/518);部分食品中汞含量的平均值为0.077 mg/kg,总体超标率为8.3%(303/3 657),其中蔬菜和粮食中超标率较高,分别为25.3%(135/534)和12.3%(68/551)。结论 河南省部分食品中铅、汞污染情况较为严重,其中粮食、蔬菜和肉类食品中污染情况尤为突出,需要加强监管。 相似文献
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Study of selenium accumulation by fish of Buryatia shows relatively high accumulation level for the Baikal lake (213-513 mcg/kg) contrary to the lakes of Baunt and Selenginsk regions of the republic (84-227 mcg/kg). Selenium deficiency in Baunt region is also confirmed by low selenium levels in meat of native origin (39-95 mcg/kg). Among different tissues and organs the lowest selenium levels are typical for muscles, the value increasing in the row: muscle < skin < air bladder < scales < fin < liver < roe. 相似文献
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转录组测序技术能将组织或细胞在不同生理条件下的差异基因量化,是探索基因功能和揭示特定生物学过程中分子机理的必要手段。储粮害虫是严重危害储藏粮食的一类害虫,从转录组水平揭示储粮害虫生长发育、关键基因功能、抗药性分子机制等成为研究热点,极大促进了对储粮害虫特别是无参考基因组信息的害虫的研究。因此,本文系统性从生长发育相关基因的挖掘、组织特异性基因、与微生物互作机制、对环境胁迫的响应机制、磷化氢抗性机理和植物精油杀虫机理研究六个方面综述了转录组学在储粮害虫研究中的应用,旨在为储粮害虫的深入研究提供参考,对进一步进行储粮害虫防治技术开发提供理论依据。 相似文献