In this work, the individual and combined effects of the extractant, surfactant and modifier concentrations on the droplet coalescence time of the primary emulsion in the liquid surfactant membrane extraction process ...In this work, the individual and combined effects of the extractant, surfactant and modifier concentrations on the droplet coalescence time of the primary emulsion in the liquid surfactant membrane extraction process were evaluated, through emulsification experiments. Adogen 464 was used as extractant (carrier), and Escaid 110, as diluent. Two systems were studied. The first one composed by the extractant, the surfactant and the diluent, and the second one composed by the same reagents, but with the addition of 1-decanol as modifier. It was observed that, when the modifier is not present in the membrane phase, the surfactant not only stabilizes the primary emulsion, but, apparently, it also plays a role similar to that of the alcohol, promoting the solvation of the amine in a low polarity diluent. Furthermore, the extractant, a quaternary amine, helps to stabilize the primary emulsion in systems without a modifier. For membrane phases consisting of 1 or 5% w/w of Adogen 464 and 2% or 5% w/w of ECA 4360, a concentration of 3% w/w of 1-decanol was sufficient to promote the solvation of Adogen 464 in Escaid 110 and to obtain a low droplet coalescence time.展开更多
目的分析微滴式数字PCR(ddPCR)和实时荧光定量PCR(qPCR)检测人巨细胞病毒(HCMV)核酸的结果,比较两种方法的差异性,并评估ddPCR技术的临床有效性和实用性。方法收集306例疑似HCMV感染相关疾病患者血浆标本,采用ddPCR和qPCR两种方法测定...目的分析微滴式数字PCR(ddPCR)和实时荧光定量PCR(qPCR)检测人巨细胞病毒(HCMV)核酸的结果,比较两种方法的差异性,并评估ddPCR技术的临床有效性和实用性。方法收集306例疑似HCMV感染相关疾病患者血浆标本,采用ddPCR和qPCR两种方法测定同一份标本的HCMVDNA载量。结果疑似HCMV感染人群中,基于ddPCR的检测结果,男性和女性的阳性率差异无统计学意义(χ^(2)=1.07,P>0.05);不同年龄段的病例阳性率差异无统计学意义(χ^(2)=0.03,P>0.05);不同疾病类型的样本阳性率差异有统计学意义(χ^(2)=10.38,P<0.05)。采用ddPCR方法检测的阳性率为46.41%(120/306),采用qPCR方法检测的阳性率为22.86%(70/306),阳性率差异有统计学意义(χ^(2)=103.80,P<0.05)。受试者工作特征曲线(ROC)分析显示,ddPCR检测的灵敏度为0.96,特异性为0.97,ROC曲线下面积(Area Under Curve,AUC)为0.98。结论采用ddPCR检测HCMVDNA比qPCR具有更好的可定量性,尤其是在低浓度样本检测中更具优势,可以进一步作为临床诊断的直接方法,对现有qPCR检测体系做出有益补充和升级。展开更多
Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in dise...Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in disease management.In this study,we adapted a quantitative real-time PCR(qPCR)assay to droplet digital PCR(ddPCR)format for A.citrulli detection by optimizing reaction conditions.The performance of ddPCR in detecting A.citrulli pure culture,DNA,infested watermelon/melon seed and commercial seed samples were compared with multiplex PCR,qPCR,and dilution plating method.The lowest concentrations detected(LCD)by ddPCR reached up to 2 fg DNA,and 102 CFU mL–1 bacterial cells,which were ten times more sensitive than those of the qPCR.When testing artificially infested watermelon and melon seed,0.1%infestation level was detectable using ddPCR and dilution plating method.The 26 positive samples were identified in 201 commercial seed samples through ddPCR,which was the highest positive number among all the methods.High detection sensitivity achieved by ddPCR demonstrated a promising technique for improving seed-transmitted pathogen detection threshold in the future.展开更多
基金acknowledge CAPES,CNPq,FAPEMIG and PRPq by the financial support.
文摘In this work, the individual and combined effects of the extractant, surfactant and modifier concentrations on the droplet coalescence time of the primary emulsion in the liquid surfactant membrane extraction process were evaluated, through emulsification experiments. Adogen 464 was used as extractant (carrier), and Escaid 110, as diluent. Two systems were studied. The first one composed by the extractant, the surfactant and the diluent, and the second one composed by the same reagents, but with the addition of 1-decanol as modifier. It was observed that, when the modifier is not present in the membrane phase, the surfactant not only stabilizes the primary emulsion, but, apparently, it also plays a role similar to that of the alcohol, promoting the solvation of the amine in a low polarity diluent. Furthermore, the extractant, a quaternary amine, helps to stabilize the primary emulsion in systems without a modifier. For membrane phases consisting of 1 or 5% w/w of Adogen 464 and 2% or 5% w/w of ECA 4360, a concentration of 3% w/w of 1-decanol was sufficient to promote the solvation of Adogen 464 in Escaid 110 and to obtain a low droplet coalescence time.
文摘目的分析微滴式数字PCR(ddPCR)和实时荧光定量PCR(qPCR)检测人巨细胞病毒(HCMV)核酸的结果,比较两种方法的差异性,并评估ddPCR技术的临床有效性和实用性。方法收集306例疑似HCMV感染相关疾病患者血浆标本,采用ddPCR和qPCR两种方法测定同一份标本的HCMVDNA载量。结果疑似HCMV感染人群中,基于ddPCR的检测结果,男性和女性的阳性率差异无统计学意义(χ^(2)=1.07,P>0.05);不同年龄段的病例阳性率差异无统计学意义(χ^(2)=0.03,P>0.05);不同疾病类型的样本阳性率差异有统计学意义(χ^(2)=10.38,P<0.05)。采用ddPCR方法检测的阳性率为46.41%(120/306),采用qPCR方法检测的阳性率为22.86%(70/306),阳性率差异有统计学意义(χ^(2)=103.80,P<0.05)。受试者工作特征曲线(ROC)分析显示,ddPCR检测的灵敏度为0.96,特异性为0.97,ROC曲线下面积(Area Under Curve,AUC)为0.98。结论采用ddPCR检测HCMVDNA比qPCR具有更好的可定量性,尤其是在低浓度样本检测中更具优势,可以进一步作为临床诊断的直接方法,对现有qPCR检测体系做出有益补充和升级。
基金supported by the the National Key Research and Development Program of China (2017YFD0201602)the National Natural Science Foundation of China (31401704)the Beijing Academy of Agriculture and Forestry Foundation, China (KJCX20180203)
文摘Bacterial fruit blotch caused by Acidovorax citrulli is a serious threat to cucurbit industry worldwide.The pathogen is seedtransmitted,so seed detection to prevent distribution of contaminated seed is crucial in disease management.In this study,we adapted a quantitative real-time PCR(qPCR)assay to droplet digital PCR(ddPCR)format for A.citrulli detection by optimizing reaction conditions.The performance of ddPCR in detecting A.citrulli pure culture,DNA,infested watermelon/melon seed and commercial seed samples were compared with multiplex PCR,qPCR,and dilution plating method.The lowest concentrations detected(LCD)by ddPCR reached up to 2 fg DNA,and 102 CFU mL–1 bacterial cells,which were ten times more sensitive than those of the qPCR.When testing artificially infested watermelon and melon seed,0.1%infestation level was detectable using ddPCR and dilution plating method.The 26 positive samples were identified in 201 commercial seed samples through ddPCR,which was the highest positive number among all the methods.High detection sensitivity achieved by ddPCR demonstrated a promising technique for improving seed-transmitted pathogen detection threshold in the future.
