应用流式细胞术鉴定死活结核分枝杆菌的实验研究

【目的】探讨碘化丙锭（PI）和6-羧基荧光素二乙酸酯（6-cFDA）鉴别死、活结核分枝杆菌的性能，为应用流式细胞术定量检测与分析结核分枝杆菌药物敏感性和异质性耐药方法的创建提供基础性实验依据。【方法】应用PI和6-cFDA分别对10株1麦氏浊度结核分枝杆菌纯培养活菌悬液和其相应的1麦氏浊度85℃加热30min的死菌悬液进行染色，应用流式细胞术检测其平均荧光强度（MFI），依据受试者工作特征曲线（ROC）确定区分死菌与活菌的MFI界值，然后对另外10株活菌悬液和10株死菌悬液进行相同实验，利用前述MFI界值进行细菌死活判定。【结果】①在确定MFI界值实验中：10份死菌悬液样本PI染色的MFI值呈非正态分布，其中位值为2459，10份活菌悬液样本PI染色的MFI值呈正态分布，其均值为426±180，PI染色鉴定死菌的MFI界值为1329；10份死、活菌悬液样本6-cFDA染色的MFI值均呈正态分布，其均值分别为49±4和7144±4512，6-cFDA染色鉴定活菌的MFI界值为1021。②应用PI染色鉴定死菌的MFI界值和6-cFDA染色鉴定活菌的MFI界值检测另外10株活菌悬液和10株死菌悬液，其准确度分别为95%和100%，灵敏度分别为1.00和1.00，特异度分别为0.90和1.00，Yonde指数分别为0.90和1.00，阳性预测值分别为0.91和1.00，阴性预测值分别为1.00和1.00。【结论】PI染色能够良好鉴定结核分枝杆菌死菌、6-cFDA染色能够良好鉴定结核分枝杆菌活菌，基于PI、6-cFDA染色鉴定结核分枝杆菌活性将具有广阔的应用前景

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors