Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the environment.Among these measurement methods,the closed-loop method is frequently used.However,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation chamber.The CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and visually.In this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the chamber.The consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was verified.The effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were investigated.Based on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion effect.The CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two methods.An abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was considered.Based on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and analyzed.The in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the measurements.The consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air interface.The synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

Reference device for calibration of radon exhalation rate measuring instruments and its performance

Environmental radon emanates from the exhalation and release of soil,rocks,and building materials.Environmental radon contamination tracing and radon pollution prevention and control require the measurement of the radon exhalation rate on media surfaces.Reliable measurements of the radon exhalation rate cannot be achieved without regular calibration of the measuring instrument with a high-performance reference device.In this study,a reference device for the calibration of radon exhalation rate measuring instruments was developed using a diffusion solid radon source with a high and stable radon emanation coefficient,an integrated diffusion component composed of a plasterboard and a high-density wooden board,an air pressure balance device,a radon accumulation chamber,and a support structure.The uniformity and stability of the reference device were evaluated using the activated carbon-γspectrum and open-loop method,respectively,to measure the radon exhalation rate.The reference device achieved different radon exhalation rates by using different activities of diffusion solid radon sources.Nineteen measurement points were regularly selected on the radon exhalation surface of the reference device,and the uniformity of the radon exhalation rate exceeded 5%.The short-term stability of the reference device was better than 5%under different environmental conditions and was almost unaffected by the ambient air pressure,environmental temperature,and relative humidity.

Radon Concentration in Soil and Radon Exhalation Rate at Al-Dora Refinery and Surrounding Area in Baghdad

Radongas concentrations in soil samples were determined from depths (surface, 15, and 30) cm for nine locations in Al-Dora refinery and surrounding area using “sealed can technique” and CR-39 solid state nuclear track detectors. The radon concentration in surface samples ranged from 810.08 to 1380.08 Bq/m3 with an average 1137.71 Bq/m3. The radon concentration in soil at the depth 15 cm was ranged from 490.5 to 1197.52 Bq/m3 with an average 732.78 Bq/m3 and at the depth 30 cm was ranged from 362.07 to 889.53 Bq/m3 with an average 529.41 Bq/m3. The surface exhalation rate in surface soil samples ranged was 0.44, to 0.99 Bq·m-2·h-1 with average 0.61 Bq·m-2·h-1. The surface exhalation rate in soil samples at the depth 15 cm was ranged from 0.22 to 0.64 Bq·m-2·h-1 with average 0.39 Bq·m-2·h-1. The surface exhalation rate in soil samples at the depth 15 cm was ranged from 0.22 to 0.64 Bq·m-2·h-1 with average 0.39 Bq·m-2·h-1. The surface exhalation rate and the mass exhalation rate in soil samples at the depth 30 cm ranged from 0.19, to 0.48 Bq·m-2·h-1 with average 0.28 Bq·m-2·h-1. The mass exhalation rate in surface soil samples ranged from 0.09 to 0.21 Bq·kg-1·h-1 with average 0.12 Bq·kg-1·h-1. The mass exhalation rate in soil samples from depth 15 cm was ranged from 0.046 to 0.14 Bq·kg-1·h-1 with average 0.08 Bq·kg-1·h-1. The mass exhalation rate in soil samples at the depth 30 cm was ranged from 0.042 to 0.1 Bq·kg-1·h-1 with average 0.06 Bq·kg-1·h-1.

IN—SITU MEASUREMENTS OF RADON EXHALATION RATE FROM BUILDING SURFACE IN HONG KONG

EPA-standardized activated charcoal canisters were used to collect radon exhaled from building surfaces and analyzed using γ-spectroscopy to obtain the radon exhalation rates. More than 120 samples were analyzed in more than 10 buildings situated in different areas of Hong Kong. Variations were identified in the exhalation rates at different levels in a building, for different covering materials and for the presence of cracks in walls. The radon exhalation rate from the most common concrete walls and covering materials was found to be approximately 13 mBq·m-2·s-1. This may be the cause of a relatively high indoor radon concentration in Hong Kong.

Sea-floor exhalative sedimentary and magmatic hydrothermal superimposition on the Bainiuchang polymetallic deposit in Yunnan Province: REE geochemical evidence

In order to study the characteristics of sea-floor exhalative sedimentary and magmatic hydrothermal superimposition on the Bainiuchang polymetallic deposit, the REE compositions of the granites, host-rocks and ores have been systematically analyzed by ICP-MS. As viewed from their REE compositions, the granites show obvious negative Eu anomalies and weak negative Ce anomalies. According to their REE characteristics, the host-rocks were derived partly from sea-floor exhalative sediments. In terms of their REE compositions, the ores can be divided into two groups: one group, of which the samples were collected from the Baiyang segment relatively far away from the Bozhushan granite batholith, possesses positive Eu anomalies or no Eu anomaly and negative Ce anomalies, indicating that ore-forming hydrothermal fluid was relatively reductive and its temperature was higher than 250 ℃. Furthermore, the coinstantaneous presence of positive Eu anomalies and negative Ce anomalies indicate that the convective mixing of a little amount of seawater with hydrothermal fluid had happened while ores were precipitated on ancient sea floor. The other group, of which the samples were mainly collected from the Chuanxindong and Duimenshan segments near the Bozhushan granite batholith, has similar chondrite-monalized REE distribution patterns to those of the magmatic rocks. But as a whole, the REE characteristics of both groups change gradually starting from the Bozhushan granite batholith. Based on the REE characteristics of the granites, host-rocks and ores, it is suggested that the ore-forming metals seem to have come from several different sources.

Assay of some volatile compounds in human exhalation

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Measurement of Natural Radioactivity and Radon Exhalation Rate in Coal Ash Samples from a Thermal Power Plant

Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that 226Ra activities and 232Th in both ash samples are well above the permissible activity. The values of the external risk index (Hex) and internal one (Hin) for these ashes are below unity, with the exception of 1.28 in fly ash for Hin. The obtained values for the equivalent radium Raeq and annual effective doses Ėin fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m-2⋅h-1 and 381 mBq⋅m-2⋅h-1, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.

Breath-by-breath measurement of exhaled ammonia by acetonemodifier positive photoionization ion mobility spectrometry via online dilution and purging sampling

Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH_(3)with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH_(3)product ion peak of(C_(3)H_(6)O)_(4)NH_(4)^(+)(K_(0)=1.45 cm^(2)/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C_(3)H_(6)O)_(2)H^(+)(K_(0)=1.87 cm^(2)/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH_(3)qualitative identification.Moreover,the interference of high humidity and the memory effect of NH_(3)molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92μmol/L with a response time of 40 ms was achieved,and the exhaled NH_(3)profile could be synchronized with the concentration curve of exhaled CO_(2).Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH_(3)of healthy subjects,demonstrating its great potential for clinical disease diagnosis.

Diagnostic role of fractional exhaled nitric oxide in pediatric eosinophilic esophagitis, relationship with gastric and duodenal eosinophils

BACKGROUND Eosinophilic esophagitis(EoE)is an eosinophilic-predominant inflammation of the esophagus diagnosed by upper endoscopy and biopsies.A non-invasive and cost-effective alternative for management of EoE is being researched.Previous studies assessing utility of fractional exhaled nitric oxide(FeNO)in EoE were low powered.None investigated the contribution of eosinophilic inflammation of the stomach and duodenum to FeNO.AIM To assess the utility of FeNO as a non-invasive biomarker of esophageal eosinophilic inflammation for monitoring disease activity.METHODS Patients aged 6-21 years undergoing scheduled upper endoscopy with biopsy for suspected EoE were recruited in our observational study.Patients on steroids and with persistent asthma requiring daily controller medication were excluded.FeNO measurements were obtained in duplicate using a chemiluminescence nitric oxide analyzer(NIOX MINO,Aerocrine,Inc.;Stockholm,Sweden)prior to endoscopy.Based on the esophageal peak eosinophil count(PEC)/high power field on biopsy,patients were classified as EoE(PEC≥15)or control(PEC≤14).Mean FeNO levels were correlated with presence or absence of EoE,eosinophil counts on esophageal biopsy,and abnormal downstream eosinophilia in the stomach(PEC≥10)and duodenum(PEC≥20).Wilcoxon rank-sum test,Spearman correlation,and logistic regression were used for analysis.P value<0.05 was considered significant.RESULTS We recruited a total of 134 patients,of which 45 were diagnosed with EoE by histopathology.The median interquartile range FeNO level was 17 parts per billion(11-37,range:7-81)in the EoE group and 12 parts per billion(8-19,range:5-71)in the control group.After adjusting for atopic diseases,EoE patients had significantly higher FeNO levels as compared to patients without EoE(Z=3.33,P<0.001).A weak yet statistically significant positive association was found between the number of esophageal eosinophils and FeNO levels(r=0.30,P<0.005).On subgroup analysis within the EoE cohort,higher FeNO levels were noted in patients with abnormal gastric(n=23,18 vs 15)and duodenal eosinophilia(n=28,21 vs 14);however,the difference was not statistically significant.CONCLUSION After ruling out atopy as possible confounder,we found significantly higher FeNO levels in the EoE cohort than in the control group.

The IOMT-Based Risk-Free Approach to Lung Disorders Detection from Exhaled Breath Examination

The lungs are the main fundamental part of the human respiratory system and are among the major organs of the human body.Lung disorders,including Coronavirus(Covid-19),are among the world’s deadliest and most life-threatening diseases.Early and social distance-based detection and treatment can save lives as well as protect the rest of humanity.Even though X-rays or Computed Tomography(CT)scans are the imaging techniques to analyze lung-related disorders,medical practitioners still find it challenging to analyze and identify lung cancer from scanned images.unless COVID-19 reaches the lungs,it is unable to be diagnosed.through these modalities.So,the Internet of Medical Things(IoMT)and machine learning-based computer-assisted approaches have been developed and applied to automate these diagnostic procedures.This study also aims at investigating an automated approach for the detection of COVID-19 and lung disorders other than COVID-19 infection in a non-invasive manner at their early stages through the analysis of human breath.Human breath contains several volatile organic compounds,i.e.,water vapor(5.0%–6.3%),nitrogen(79%),oxygen(13.6%–16.0%),carbon dioxide(4.0%–5.3%),argon(1%),hydro-gen(1 ppm)(parts per million),carbon monoxide(1%),proteins(1%),isoprene(1%),acetone(1%),and ammonia(1%).Beyond these limits,the presence of a certain volatile organic compound(VOC)may indicate a disease.The proposed research not only aims to increase the accuracy of lung disorder detection from breath analysis but also to deploy the model in a real-time environment as a home appliance.Different sensors detect VOC;microcontrollers and machine learning models have been used to detect these lung disorders.Overall,the suggested methodology is accurate,efficient,and non-invasive.The proposed method obtained an accuracy of 93.59%,a sensitivity of 89.59%,a specificity of 94.87%,and an AUC-Value of 0.96.

基于临床资料和一氧化氮相融合的毛细支气管炎发生反复喘息的预测模型构建及验证

目的构建关于毛细支气管炎后发生反复喘息的Nomogram预测模型,为临床反复喘息的患儿提供更科学的防治和临床决策指导。方法选取2022年1月至2022年12月于山东省临朐县人民医院儿科就诊并诊断毛细支气管炎的住院患儿作为研究对象,收集临床资料及呼出气一氧化氮(FeNO)等相关指标,出院后随访1年,根据随访期间是否发生反复喘息分为观察组(反复喘息)和对照组(未发生反复喘息)。将两组参数通过Lasso回归和单因素Logistic回归分析筛选出有意义的变量,纳入多因素Logistic回归分析,建立关于毛细支气管炎后发生反复喘息的Nomogram预测模型。采用Hosmer-Lemeshow拟合优度检验,计算C指数和受试者工作特征曲线下面积(AUC),评价模型的准确性。应用决策曲线评价列线图的临床应用价值。结果共85例患儿纳入本研究,其中观察组17例,对照组68例。在一般资料分析中发现,FeNO(P=0.048)和淋巴细胞计数(P=0.023)存在组间差异。分别纳入单因素Logistic回归分析和Lasso回归分析。单因素Logistic回归经过年龄和性别调整后,发现FeNO[OR=1.242,95%CI=(1.002,1.541),P=0.048]和淋巴细胞计数[OR=1.428,95%CI=(1.028,1.985),P=0.034],差异有统计学意义;Lasso回归分析,其最小均方误差的λ为0.042,对应模型的变量选择为FeNO和淋巴细胞计数。多因素Logistic回归方程建立预测毛细支气管炎反复喘息发生的Nomogram列线图模型后,Hosmer-Lemeshow检验χ^(2)=3.881,P=0.868,C指数为0.706,FeNO和淋巴细胞计数AUC分别为0.654和0.674,表明该评分模型工作效果良好。决策曲线分析发现模型=反复喘息-FeNO+淋巴细胞计数具有较好的临床应用价值。结论通过FeNO和淋巴细胞计数建立的关于毛细支气管炎后发生反复喘息的Nomogram预测模型具有较好的临床应用价值。

温润辛金方治疗微寒恋肺型咳嗽变异型哮喘的临床疗效研究

目的:观察温润辛金方治疗微寒恋肺型咳嗽变异型哮喘(CVA)的临床疗效及安全性,为CVA的中医临床治疗提供依据和思路。方法:选取2017年6月~2019年12月期间于某院就诊的60例微寒恋肺型CVA患者,根据随机数字表法分为对照组和观察组,每组30例。对照组给予沙美特罗替卡松吸入粉雾剂,观察组给予温润辛金方,两组均治疗6周。观察两组患者的中医证候疗效以及不良反应,比较两组患者治疗前后呼出气一氧化氮(FeNO)及咳嗽症状积分的变化。结果:对照组和观察组分别脱落2例和4例。两组临床治疗总有效率比较无统计学差异(P>0.05)。治疗后,两组咳嗽症状积分、FeNO均较治疗前下降(P<0.05),且观察组咳嗽症状积分低于对照组(P<0.05),但两组FeNO水平比较无统计学差异(P>0.05)。观察组有2例患者在服药期间出现恶心等胃部不适,嘱其改为饭后服药后症状消失;对照组有2例患者出现轻微不良反应,但不影响后续治疗。结论:温润辛金方可有效改善微寒恋肺型CVA患者的临床症状和咳嗽症状积分,临床疗效较佳且安全性良好。

呼出气一氧化氮、肺泡一氧化氮和嗜酸性粒细胞对3~6岁儿童呼吸系统疾病的鉴别诊断价值

目的探讨呼出气一氧化氮(FeNO)、肺泡一氧化氮(CaNO)和嗜酸性粒细胞(EOS)在甘肃省兰州市3~6岁儿童呼吸系统疾病鉴别诊断中的应用价值。方法选取确诊哮喘或过敏性鼻炎或下呼吸道感染的360例3~6岁儿童作为研究对象,采用斯皮尔曼秩相关系数评估FeNO、CaNO、EOS的相关性,通过随机森林模型、受试者工作特征(ROC)曲线、多因素逻辑回归分析评估FeNO、CaNO和EOS对3种疾病的鉴别诊断价值。结果哮喘患儿的FeNO、CaNO中位数高于其他疾病患儿,过敏性鼻炎患儿的EOS中位数最低,下呼吸道感染患儿的FeNO、CaNO中位数最低。相关性分析结果显示,FeNO与CaNO呈正相关(r=0.59,P<0.05),FeNO与EOS呈负相关(r=-0.61,P<0.05),CaNO与EOS呈负相关(r=-0.63,P<0.05)。随机森林模型显示,FeNO在疾病分类中的重要性最高。ROC曲线分析结果显示,3种疾病中,FeNO、CaNO、EOS对下呼吸道感染的诊断效能均最高(曲线下面积分别为0.86、0.91、1.00)。多因素逻辑回归模型诊断哮喘的曲线下面积为0.96,灵敏度为0.902,特异度为0.881。结论FeNO、CaNO和EOS在鉴别诊断兰州地区3~6岁儿童哮喘、过敏性鼻炎、下呼吸道感染方面展现出较好的潜力,且基于三者构建的多因素逻辑回归模型可有效提升对哮喘的诊断准确性。

宣肺化湿止咳汤联合西药治疗咳嗽变异性哮喘临床观察

目的研究宣肺化湿止咳汤治疗咳嗽变异性哮喘的临床效果及对呼出气一氧化氮(FeNO)数值的影响。方法选择2018年7月—2019年12月收治的120例咳嗽变异性哮喘患者作为研究对象,40例采用沙美特罗替卡松粉(舒利迭)吸入治疗作为西药组,40例采用宣肺化湿止咳汤治疗作为中药组,最后40例采用二者联合治疗作为联合组。观察三组治疗效果、咳嗽症状积分、FeNO水平、咳嗽生活质量以及不良反应情况。结果联合组的治疗总有效率为97.5%(39/40),明显高于西药组的80.0%(32/40)、中药组的82.5%(33/40),差异有统计学意义(P<0.05);治疗后联合组FeNO水平低于西药组和中药组,莱切斯特咳嗽问卷(LCQ)评分高于西药组和中药组,日间积分与夜间积分均低于西药组和中药组,差异均有统计学意义(P<0.05);西药组和中药组FeNO水平、LCQ评分、日间积分与夜间积分对比,差异无统计学意义(P>0.05)。结论宣肺化湿止咳汤联合西药治疗咳嗽变异性哮喘,效果较好,能明显减轻患者临床症状,提高生活质量,降低炎症反应,值得临床应用及推广。

呼出气一氧化氮检测与慢性阻塞性肺疾病严重程度的相关性分析

目的 探讨呼出气一氧化氮(fraction of exhaled nitric oxide,FeNO)水平与慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)严重程度的相关性。方法 选择2017年9月—2019年9月就诊于昆明医科大学第五附属医院的稳定期COPD患者178例及同期体检健康志愿者43例,分别进行FeNO稳态浓度及肺功能检测,记录第1秒用力呼气容积(FEV1)及第1秒用力呼气容积占预计值百分比(FEV1%pred)。依据COPD患者气流受限肺功能分级分成GOLD 1级(n=30)、2级(n=78)、3级(n=40)、4级(n=30)四个亚组;然后再根据慢阻肺综合评估分成A组(n=50)、B组(n=34)、C组(n=46)、D组(n=48)四个亚组,比较COPD病例组与健康组以及各个亚组之间的Fe NO水平,并分析Fe NO与FEV1、FEV1%pred的相关性。结果 (1)稳定期COPD组的FeNO水平高于健康组(P <0.05)。(2) COPD患者FeNO与FEV1、FEV1%pred均无相关性(P> 0.05),GOLD1级、2级、3级、4级不同亚组的FeNO水平比较差异无统计学意义(P> 0.05)。(3)慢阻肺综合评估C组的FeNO水平高于A组(P <0.05),其余各组间FeNO值比较差异无统计学意义(P> 0.05)。结论 FeNO检测不能替代肺功能、慢阻肺综合评估分级,对COPD患者病情需进行单独评估,但FeNO检测可能有助于COPD的初筛诊断及未来急性加重风险预测。

基于机器视觉的呼出气体酒精含量检测仪自动检定装置

当前呼出气体酒精含量检测仪检定工作耗时耗力,检定过程需要人工进行判读和记录,针对该问题研制一套呼出气体酒精含量检测仪自动检定装置。依据检定规程的要求,设计配气装置实现对气体的气路设计及温度和流量等的控制。基于机器视觉系统使用Halcon联合C#开发识别算法,利用Canny边缘算法提取感兴趣区域,定位提取示值字符后训练多层感知器来识别示值结果,并实现检定过程的自动选择和报告的自动生成。实验结果表明:对五种型号的呼出气体酒精含量检测仪示值的识别准确率达到了99.5%以上,平均识别时间小于200 ms,对后续检定的平均全过程时间从3.5天缩短至1.5天。该装置满足检定规程的要求,可以应用于各地计量机构的检定工作中,具有实用价值。

面向肺癌筛查的呼出气检测电子鼻设计与应用

人体呼出气包含的挥发性有机化合物(Volatile Organic Compounds,VOCs)与人体健康和疾病状态密切相关。电子鼻将气体传感器阵列与模式识别算法结合,可实现气味的识别与分类。针对肺癌患者诊治端口前移需求,开展呼出气检测电子鼻系统的设计与应用研究,基于半导体气体传感器阵列优化电路与气路设计,构建便携式电子鼻系统样机,对129例临床呼出气样本进行检测;通过数据处理与统计分析,研究健康对照(51例)与肺部疾病患者(78例)的分类效果。结果表明,设计的电子鼻对肺部疾病患者的识别准确率达89.1%(敏感性83.3%,特异性98.0%),展现出应用于肺癌早期筛查的潜力,有望成为一种无创、便捷的肺部疾病辅助诊断方法。

冷凝收集-离子色谱法测定呼出气中的有机酸和阴离子

建立了一种非侵入式冷凝收集-离子色谱方法测定人体呼出气中乳酸、甲酸、乙酸、丙酮酸、Cl^(-)、NO_(2)^(-)、NO_(3)^(-)、SO_(4)^(2-)。搭建自制呼出气冷凝装置,该装置包括吹气口、与吹气口相连的单向阀和流量计、置于半导体冷凝装置中的冷阱以及一次性冷凝收集管。通过呼出气冷凝装置对人体呼出气进行收集,利用离子色谱对冷凝液(EBC)中有机酸和阴离子的含量进行检测。优化采集冷阱温度和采集流量,得到冷阱最佳冷凝温度为-15℃,呼气流量为15 L/min。采用1.5 mmol/L碳酸钠和3 mmol/L碳酸氢钠混合溶液作为流动相,泵流速为0.8 mL/min,分析柱为IC-SA3(250 mm×4.0 mm),柱温为45℃。8种有机酸和阴离子的线性范围均为0.1~10.0 mg/L,相关系数均≥0.9993。在进样量为100μL时,方法的检出限为0.0017~0.0150 mg/L(S/N=3),定量限为0.0057~0.0500 mg/L(S/N=10)。方法的日内和日间精密度均≤7.50%(n=5)。采用该方法对5位健康受试者呼出气中的有机酸和阴离子进行检测,得到8种有机酸和阴离子的含量为0.18~42.3 ng/L。在10 km的长跑运动过程中,除了一位受试者代谢异常,其余受试者呼出气中的有机酸和阴离子含量总体变化趋势为先增加后减小。本方法采样过程简单,精密度好,且没有副作用,受试者不会产生任何明显不适或风险,可为日后人体代谢物的研究提供实验思路和理论依据。

FeNO联合TSLP对儿童咳嗽变异性哮喘与感染后咳嗽的鉴别价值及与小气道功能的关系

目的探究呼出气一氧化氮(FeNO)联合胸腺基质淋巴细胞生成素(TSLP)对儿童咳嗽变异性哮喘(CVA)与感染后咳嗽(PIC)的鉴别价值,并分析FeNO、TSLP与CVA病情、小气道功能的关系,为临床诊疗提供有利依据。方法选取2021年6月至2023年4月郑州大学第一附属医院儿科诊治收治的90例CVA患儿作为CVA组,另选取同期90例PIC患儿作为PIC组。比较两组患儿的临床资料和FeNO、TSLP水平,绘制受试者工作特征(ROC)曲线及曲线下面积(AUC)分析FeNO联合TSLP对CVA与PIC的鉴别价值;比较CVA不同病情严重程度和病情阶段患儿的小气道功能[FEF25(%)、FEF50(%)、FEF75(%)、FEF25~75(%)]和FeNO、TSLP水平,采用Spearman和Pearson相关系数法分析FeNO、TSLP与CVA小气道功能、病情阶段、病情严重程度的相关性。结果CVA组患儿的FeNO、TSLP水平明显高于PIC组,差异均有统计学意义(P<0.05);ROC分析结果显示,FeNO联合TSLP鉴别CVA与PIC的AUC最大(0.934),敏感度、特异度为87.78%、82.22%,明显高于各指标单独诊断(P<0.05);轻度组患儿的FEF25、FEF50、FEF75和FEF25~75>中度组>重度组,差异均有统计学意义(P<0.05);轻度组患儿的FeNO、TSLP水平<中度组<重度组,差异均有统计学意义(P<0.05);临床缓解期组患儿的FEF25、FEF50、FEF75、FEF25~75明显高于急性发作期组,FeNO、TSLP水平明显低于急性发作期组,差异均有统计学意义(P<0.05);Pearson相关系数法分析结果显示,FeNO、TSLP与FEF25、FEF50、FEF75、FEF25~75均呈负相关(P<0.05);Spearman相关系数法分析结果显示,FeNO、TSLP与病情阶段、病情严重程度均呈正相关(P<0.05)。结论与PIC患儿比较,CVA患儿FeNO、TSLP水平异常升高,其联合鉴别诊断CVA与PIC具有较高价值,且FeNO、TSLP水平与患儿病情、小气道功能密切相关。