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@#Objective To investigate the predictive value of volatile organic compounds (VOCs) on pulmonary nodules in people aged less than 50 years. Methods The 147 patients with pulmonary nodules and aged less than 50 years who were treated in the Department of Thoracic Surgery of Sichuan Cancer Hospital from August 1, 2019 to January 15, 2020 were divided into a lung cancer group and a lung benign disease group. The lung cancer group included 36 males and 68 females, with the age of 27-49 (43.54±5.73) years. The benign lung disease group included 23 males and 20 females, with the age of 22-49 (42.49±6.83) years. Clinical data and exhaled breath samples were collected prospectively from the two groups. Exhaled breath VOCs were analyzed by gas chromatography mass spectrometry. Binary logistic regression analysis was used to select variables and establish a prediction model. The sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve of the prediction model were calculated. Results There were statistically significant differences in sex (P=0.034), smoking history (P=0.047), cyclopentane (P=0.002), 3-methyl pentane (P=0.043) and ethylbenzene (P=0.009) between the two groups. The sensitivity, specificity and area under the ROC curve of the prediction model with gender, cyclopentane, 3-methyl pentane, ethylbenzene and N,N-dimethylformamide as variables were 80.8%, 60.5% and 0.781, respectively. Conclusion The combination of VOCs and clinical characteristics has a certain predictive value for the benign and malignant pulmonary nodules in people aged less than 50 years.
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Laser-induced breakdown spectroscopy has become a very attractive technique in the field of chemical analysis.The technique utilizes a laser focused on a small spot to create a micro-plasma on the sample surface.In recent years, laser-induced breakdown spectroscopy (LIBS) is a frontier analysis technique in spectrometric analysis, with the advantages such as real-time, online and non-contact analysis.The research and development of various instruments based on this technology has attracted great attention of researchers.In the article, we reviewed the research progress of LIBS instrument from the components and field equipment in recent years, mainly including portable LIBS, handheld LIBS and remote LIBS.
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A novel method for the determination of metallic elements in environmental samples was developed based on the matrix-assisted plasma surface sampling atomic emission spectrometry ( AES system) . A piece of filter paper was used as sample substrate. By direct interaction of the plasma tail plume with the filter paper surface, the filter paper absorbed energy from the plasma source and released combustion heating to the analytes originally present on its surface, thus to promote the atomization and excitation process. Surface sampling was performed in both cases of liquid and solid state analytes. Therefore, no flow injection system was required and sample pretreatment process was simplified. The proposed method provides several advantages, including fast analysis speed ( about 240 samples/h ) , little sample consumption (μL or μg level) , simplicity in instrument design, and also ease of system operation. These advantages made it attractive as a potential miniaturized AES system for in situ and high-throughput elemental analyses. Quantitative analysis of metal ions were achieved in this study for elements Ag, Au, Ba, Cd, Cr, Cu, Eu, La, Mn, Ni, Pb, Sr and Y. Under optimal conditions, the LOD values of the 13 elements ranged from 1. 0 to 88 μg/L. The repeatability, expressed as relative standard deviation ( RSD) from 10 replicates, ranged from 2. 3% to 6. 8%. To validate the proposed method, the system was employed to determine metal elements in standard reference materials of environmental samples. The content of each element was well in agreement with the certified values.