质子转移反应质谱对肺癌患者呼气中特征性VOCs的筛选及研究

利用质子转移反应质谱(PTR-MS)对40名肺癌患者、32名健康志愿者呼出气体中的挥发性有机物(VOCs)进行检测,Mann-Whitney秩和检验与多因素logistic回归的结果表明,呼气中VOC 33、VOC 39、VOC 45可能为肺癌人群的呼气标志物,同时VOC 45在小细胞肺癌和非小细胞肺癌患者之间存在显著差异。以肺癌人群的呼气标志物作为自变量,采用二元logistic回归分析和Fisher判别分析分别建立肺癌预测模型。logistic回归模型的受试者工作曲线下面积(AUC)达到0.878,灵敏度和特异性分别为85.5%和63.5%。Fisher判别模型的受试者工作曲线下面积(AUC)达到0.822,灵敏度和特异性分别为82.5%和62.5%。两种模型对肺癌的预测均具有统计学意义。     

Factors influencing level of hydrogen peroxide in exhaled breath condensate

Hydrogen peroxide (H₂O₂) in exhaled breath condensate (EBC) has been proposed as a marker for oxidative stress in the airways. The aim of the present study was to evaluate the measurement of H₂O₂ in EBC with or without use of a nose clip, and the influence of mouth rinsing, sampling time and storage.An elevated H₂O₂ level was seen during nasal breathing compared to mouth breathing with nose clip (3.4 pmol/s vs. 2.1 pmol/s, p = 0.02). Breathing through the mouth, using a nose clip, was therefore practiced in all experiments. The H₂O₂ levels were increased when mouth rinsing was performed using an acid buffer (1.4 pmol/s vs. 1.9 pmol/s, p = 0.03). 15 min sampling time decreased the H₂O₂ output by almost 50% compared with 2 min sampling time (1.2 vs. 0.6 pmol/s, p = 0.03). When samples were left unattended for 15 min no change in H₂O₂ concentration in the EBC was seen.We found no significant differences in H₂O₂ levels between samples stored for 4 weeks at − 80 °C and samples analysed directly; however, a significant decrease in the levels was seen for samples stored for 4 weeks at − 20 °C.In conclusion, the method of EBC collection and storage plays an important role in reducing variability within and between individuals.     

Analysis of aldehydes in human exhaled breath condensates by in-tube SPME-HPLC

In this paper, polypyrrole/graphene (PPy/G) composite coating was prepared by a facile electrochemical polymerization strategy on the inner surface of a stainless steel (SS) tube. Based on the coating tube, a novel online in-tube solid-phase microextraction -high performance liquid chromatography (IT-SPME-HPLC) was developed and applied for the extraction of aldehydes in the human exhaled breath condensates (EBC). The hybrid PPy/G nanocomposite exhibits remarkable chemical and mechanical stability, high selectivity, and satisfactory extraction performance toward aldehyde compounds. Moreover, the proposed online IT-SPME-HPLC method possesses numerous superiorities, such as time and cost saving, process simplicity, high precision and sensitivity. Some parameters related to extraction efficiency were optimized systematically. Under the optimal conditions, the recoveries of the aldehyde compounds at three spiked concentration levels varied in the range of 85%–117%. Good linearity was obtained with excellent correlation coefficients (R²) being larger than 0.994. The relative standard deviations (n = 5) of the method ranged from 1.8% to 11.3% and the limits of detection were between 2.3 and 3.3 nmol L⁻¹. The successful application of the proposed method in human EBC indicated that it is a promising approach for the determination of trace aldehyde metabolites in complex EBC samples.     

基于静态呼吸图技术的图案化方法

对呼吸图技术制备二维有序多孔结构的研究进展进行了综合评述, 并重点介绍了本课题组发展的静态呼吸图技术. 利用静态呼吸图法, 可制备高度有序的聚合物、聚合物/无机物微孔膜. 这些有序的结构可以直接应用于光掩膜. 进一步, 多孔聚合物膜可以被紫外光交联和改性. 表面改性的多孔聚合物膜可以用于细胞支架. 而交联的聚合物/无机物前驱体微孔膜可以用来制备无机纳米材料阵列. 结果表明, 静态呼吸图技术是一种简单、高效的对聚合物、聚合物/无机物薄膜进行图案化的通用方法,并展示了图案化薄膜广阔的功能化前景.     

Signals in human breath related to Sarcoidosis. — Results of a feasibility study using MCC/IMS

Using a ⁶³Ni—Ion Mobility Spectrometer (IMS) coupled with a Multi-Capillary Column (MCC) the signals obtained are considered to identify characteristic peaks of volatile compounds in exhaled human breath samples of 10 mL volume. The breath of 20 patients with sarcoidosis and suspicion of sarcoidosis because of mediastinal lymp node enlargement was investigated. It could be shown that a procedure related to a single peak in the IMS-chromatogram delivers a differentiation into the two groups of patients with confirmed sarcoidosis and such suffering no sarcoidosis. The potential biomarker is characterised by the following parameters inverse mobility (1/K₀) 0.53 ± 0.01 Vs/cm²—retention time 22 ± 5 s. These results are a first step in breath analysis by MCC/IMS in patients with sarcoidosis.     

An analytical approach for on-site analysis of breath samples for Δ9-tetrahydrocannabinol (THC)

Increased acceptance of cannabis containing the psychoactive component, Δ9-tetrahydrocannabinol (THC), raises concerns about the potential for impaired drivers and increased highway accidents. In contrast to the “breathalyzer” test, which is generally accepted for determining the alcohol level in a driver, there is no currently accepted roadside test for THC in a motorist. There is a need for an easily collectible biological sample from a potentially impaired driver coupled with an accurate on-site test to measure the presence and quantity of THC in a driver. A novel breath collection device is described, which includes three separate sample collectors for collecting identical A, B, and C breath samples from a subject. A simple one-step ethanol extraction of the “A” breath collector sample can be analyzed by UHPLC/selected ion monitoring (SIM) liquid chromatography/mass spectrometry (LC/MS) to provide qualitative and quantitative determination of THC in breath sample in less than 4 min for samples collected up to 6 h after smoking a cannabis cigarette. SIM LC/MS bioanalyses employed d3-THC as the stable isotope internal standard fortified in negative control breath samples for quantitation including replicates of six calibrator standards and three quality control (QC) samples. Subsequent confirmation of the same breath sample in the B collectors was then confirmed by a reference lab by LC/MS/MS analysis. Fit-for-purpose bioanalytical validation consistent with pharmaceutical regulated bioanalyses produced pharmacokinetic (PK) curves for the two volunteer cannabis smokers. These results produced PK curves, which showed a rapid increase of THC in the breath of the subjects in the first hour followed by reduced THC levels in the later time points. A simpler single-point calibration curve procedure with calibrators and QC prepared in ethanol provided similar results. Limitations to this approach include the higher cost and operator skill sets for the instrumentation employed and the inability to actually determine driver impairment.     

势函数分析高斯光束在对数饱和非线性介质中的传播

导出了在对数饱和非线性介质中传播的强激光基模高斯光束宽度随传播距离变化的方程。此方程与势作用下粒子的运动方程形式一致,因此可用势作用下的粒子行为来描述高斯光束的呼吸模式。对势函数采用二阶近似后,求解此方程得到高斯型呼吸模式的光束宽度的近似解析式。分析了呼吸周期和呼吸深度与入射条件的关系,以及形成空间孤子的条件。     

Research on the implementing conditions of inverse emulsion-breath figure method

The relationships between three steps of the inverse emulsion-breath figure (Ie-BF) method, including emulsion preparation, film casting and hydrophilic component loading, are explored by adjusting the experimental factors of the three implementing processes. For emulsion preparation step, the influence of the ultrasonification, the concentration of emulsifier and the addition of polymer on the size of the emulsion droplets are investigated. For film casting step, the influence of environmental humidity and several factors concerning the emulsion preparation on the porous structure of the resultant films are studied. It has been proved that high humidity is a necessity for obtaining surface pores, and multi-layered pores with disordered distribution can be formed in the bulk layer of the film when high water/oil ratio is used in making the emulsion. Bovine serum albumin is loaded into the emulsion water droplets, and by implementing the Ie-BF method under the condition of water/oil ratio being as low as 0.02 vol%, selective protein enrichment within the interior of the top-layer pores is still realized. It reflects the characteristics of “high efficiency, targeted assembly” in the step of hydrophilic component loading.     

Self‐Organization of Honeycomb‐like Porous TiO2 Films by means of the Breath‐Figure Method for Surface Modification of Titanium Implants

This study describes a facile breath‐figure method for the preparation of honeycomb‐like porous TiO₂ films with an organometallic small‐molecule precursor. Multiple characterization techniques have been used to investigate the porous films and a mechanism for the formation process of porous TiO₂ films through the breath‐figure method is proposed. The pore size of the TiO₂ films could be modulated by varying the experimental parameters, such as the concentration of titanium n‐butoxide (TBT) solution, the content of cosolvent, and the air flow rate. In vitro cell‐culture experiments indicate that NIH 3T3 fibroblast cells seeded on the honeycomb‐like porous TiO₂ films show good adhesion, spreading, and proliferation behaviors, which suggests that honeycomb‐like porous TiO₂ films are an attractive biomaterial for surface modification of titanium and its alloys implants in tissue engineering to enhance their biocompatibility and bioactivity.     

Breath Analysis: Comparison among Methodological Approaches for Breath Sampling

Despite promising results obtained in the early diagnosis of several pathologies, breath analysis still remains an unused technique in clinical practice due to the lack of breath sampling standardized procedures able to guarantee a good repeatability and comparability of results. The most diffuse on an international scale breath sampling method uses polymeric bags, but, recently, devices named Mistral and ReCIVA, able to directly concentrate volatile organic compounds (VOCs) onto sorbent tubes, have been developed and launched on the market. In order to explore performances of these new automatic devices with respect to sampling in the polymeric bag and to study the differences in VOCs profile when whole or alveolar breath is collected and when pulmonary wash out with clean air is done, a tailored experimental design was developed. Three different breath sampling approaches were compared: (a) whole breath sampling by means of Tedlar bags, (b) the end-tidal breath collection using the Mistral sampler, and (c) the simultaneous collection of the whole and alveolar breath by using the ReCIVA. The obtained results showed that alveolar fraction of breath was relatively less affected by ambient air (AA) contaminants (p-values equal to 0.04 for Mistral and 0.002 for ReCIVA Low) with respect to whole breath (p-values equal to 0.97 for ReCIVA Whole). Compared to Tedlar bags, coherent results were obtained by using Mistral while lower VOCs levels were detected for samples (both breath and AA) collected by ReCIVA, likely due to uncorrected and fluctuating flow rates applied by this device. Finally, the analysis of all data also including data obtained by explorative analysis of the unique lung cancer (LC) breath sample showed that a clean air supply might determine a further confounding factor in breath analysis considering that lung wash-out is species-dependent.