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background The lead isotope ratios (LIR) differ among different sourced samples. Previous domestic and oversea studies on source tracing by LIR in human blood or urine mainly focused on the comparison of blood or urine samples from the same or different individuals, while few comparisons between biological and environmental samples, and the reported relative standard deviations (RSDs) of the main LIR (207/206Pb and 208/206Pb) fluctuate widely from 0.3% to 1%. Objective To optimize inductively coupled plasma mass spectrometry (ICP-MS), obtain a better RSD, and determine LIRs of human blood, urine, and related environmental samples. Methods The ICP-MS was optimized for operating conditions and parameters according to the sensitivity and RSD of LIR. The study subjects were 40 lead-exposed workers in a lead-acid battery factory and 2 lead poisoned children in a hospital. The samples included 40 blood and 40 urine samples from the workers before shift, 4 dust samples and 2 water samples in the workplace on the same day before shift, 2 blood and 3 urine samples from the children before hospital admission due to lead-poisoning, and 4 urine samples after medical treatment. After heating and acid digestion, the LIR (207/206Pb and 208/206Pb) of biological and environmental samples were determined by the optimized ICP-MS method. t-test and two-dimensional traceability graphics were adopted to analyze the detection results. Results The calibrated RSDs of the LIR (207/206Pb and 208/206Pb) of lead isotope standard solution were 0.11% and 0.08% respectively, and the NIST-SRM-981 actual values were 0.91531±0.00097 and 2.1670±0.0017, respectively. When the total concentration of lead was greater than 5 μg·L−1, the RSD of each isotope ratio was stable gradually; when the total concentration of lead was between 10-80 μg·L−1, the RSD was below 0.20%. There were statistically significant differences in the blood and urine LIR (207/206Pb and 208/206Pb) of the lead-exposed workers (t=5.831, P<0.001; t=21.021, P<0.001), the LIR (207/206Pb and 208/206Pb) between workplace dust samples and workers’ urine samples (t=−6.879, P=0.038; t=12.521, P<0.001), and the 208/206Pb between workplace dust samples and workers’ blood samples (t=−10.46, P<0.001), except the 207/206Pb between workplace dust samples and workers’ blood samples (t=−0.12, P=0.912). In the patients afflicted with lead poisoning, the projection points of LIR of blood and urine samples from the same individual were not at the same level in the two-dimensional model, nor was the LIR of urine samples before and after medical treatment of the same individual. Conclusion The optimized ICP-MS can control the RSD of main LIR (207/206Pb and 208/206Pb) below 0.20%. There are differences in the LIR distributions of different samples.
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Objective:To explore the in-depth experience of nursing undergraduates′ management experience and managed experience in open laboratory. Analyze management problems and offer suggestions.Methods:Using qualitative research methods and purposive sampling, from April to May of 2019, 40 nursing undergraduates were selected. Semi-structured interview was adopted to interview them and Colaizzi seven-step method was used to analyze the data.Results:Nine themes were grouped into three major parts including work content and feeling of lab assistant, students′ feelings about the management, their needs and suggestions.Conclusions:Teaching departments should pay attention to the feelings of nursing students, and encourage them to jointly build a simulative clinical environment. According to the needs of students, teachers should improve the effectiveness of practice in open laboratory by setting supporting facilities and establish a post practice evaluation.
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OBJECTIVE To investigate the forms of carbamazepine and its metabolites in the gastric juice,blood and urine samples from a poisoned patient and its metabolic pathways. METHODS The gastric juice,blood and urine samples were obtained from a patient who was rushed to the Hospital of Prevention and Treatment for Occupational Diseases to be treated for an overdose of carbamazepine for about six hours. The samples were analyzed by gas chromatography-mass spectrometry. The metabolites were identified from their mass spectra by comparison with spectra in NIST 98 libraries. The metabolic pathways were inferred by fragmentation regularities of mass spectra and the published data. RESULTS The results showed that only M1 was found in the gastric juice sample. Four metabo?lites,such as iminostilbene(M1),9-methyl-acridine(M2),9-propyl-acridan(M4)and M3,were found in the blood sample and thirteen metabolites,including M1,M2,M4,acridine(M5),acridone(M6), 9,10-dihydro Acridine (M7), 1a,10b-dihydro-6H-dibenz[b,f]oxireno[d]azepine-6-carboxamide (M8),9-acridinemethanol (M9),10,11-dihydrodiol-carbamazepine (M10),2-methyl-acridone (M12),4-methyl-acridone(M13),undetermined M3 and M11,were found in the urine from the poi?soned patient. The forms of carbamazepine metabolites in the gastric juice ,blood and urine were different. Little carbamazepine was found in the urine after metabolism. CONCLUSION Based on the analysis by gas chromatography-mass spectrometry and identification of NIST 98 libraries,the metabolites could be identified accurately,which can help analyze the metabolic mechanism and pathways of carbam?azepine.
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<p><b>OBJECTIVE</b>To establish the method of high-performance liquid chromatography HPLC for the determination of N-acetyl-S-(2-carbamoylethyl)-cysteine (AAMA) in urine.</p><p><b>METHODS</b>After acid hydrolysis, AAMA in urine was converted into S-2-carboxyethyl cysteine (CEC). CEC reacted with the derivative reagent ophthalaldehyde and formed the derivative with strong fluorescence absorption. The HPLC-fluorescence detector was applied, with an excitation wavelength of 340 nm and an emission wavelength of 450 nm.</p><p><b>RESULTS</b>Urinary AAMA demonstrated an excellent linearity in the range of 5.3~123.5 μmol/L, with a correlation coefficient of 0.9994. The minimum detectable concentration was 0.1 μmol/L (the volume of urine sample was 1.0 ml), the recovery of standard addition was 97.4%~104.2%, and the between-run precision was 2.3%~4.3%. The sample could be stored in the refrigerator for at least 7 days at a temperature of 4℃.</p><p><b>CONCLUSION</b>The method is simple, with a low cost, a high sensitivity, and good precision and accuracy, and the instrument and equipment commonly seen in laboratories are applied. Therefore, this method is worthy of wide application.</p>
