Spectrophotometric determination of silicon tetrahydride in the air of workplace / 华中科技大学学报（医学）（英德文版）

A new, simple and sensitive method was developed for the determination of silicon tetrahydride in the air of workplace in this study. The alkaline resin-based spherical activated carbon was used to collect sample of silicon tetrahydride at workplace. Silicon tetrahydride was then desorbed from active carbon in 100°C hot water. After reacting with ammonium molybdate, oxalic acid and 1,2,4-trichlorobenzene alpha-naphthol amino sulfonic acid under acid condition, silicon tetrahydride was transformed into silicon molybdenum blue. The absorbance of silicon molybdenum blue was quantitatively measured at the wavelength of 680 nm. The results showed that the average sampling efficiency and desorption efficiency were 97.53% and 94.94%, respectively by this method. Detection limits were 0.054 μg/mL for the spectrophotometric method and 0.14 mg/m(3) for the determination of silicon tetrahydride in the air of workplace (sampling volume was 7.5 L). The conversion rate of silicon tetrahydride gradually decreased when storage time of samples was extended. The descent rate of sample was less than 10% when the sample was sealed for 7 days in the room temperature. It was concluded that this spectrophotometric method can be successfully used to determine silicon tetrahydride in the worksites.

Spectrophotometric determination of silicon tetrahydride in the air of workplace / 华中科技大学学报（医学）（英德文版）

A new, simple and sensitive method was developed for the determination of silicon tetrahydride in the air of workplace in this study. The alkaline resin-based spherical activated carbon was used to collect sample of silicon tetrahydride at workplace. Silicon tetrahydride was then desorbed from active carbon in 100°C hot water. After reacting with ammonium molybdate, oxalic acid and 1,2,4-trichlorobenzene alpha-naphthol amino sulfonic acid under acid condition, silicon tetrahydride was transformed into silicon molybdenum blue. The absorbance of silicon molybdenum blue was quantitatively measured at the wavelength of 680 nm. The results showed that the average sampling efficiency and desorption efficiency were 97.53% and 94.94%, respectively by this method. Detection limits were 0.054 μg/mL for the spectrophotometric method and 0.14 mg/m(3) for the determination of silicon tetrahydride in the air of workplace (sampling volume was 7.5 L). The conversion rate of silicon tetrahydride gradually decreased when storage time of samples was extended. The descent rate of sample was less than 10% when the sample was sealed for 7 days in the room temperature. It was concluded that this spectrophotometric method can be successfully used to determine silicon tetrahydride in the worksites.

Size-dependent biological effects on vascular endothelial cells induced by different particulate matters / 华中科技大学学报（医学）（英德文版）

The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells (HUVECs) were exposed to increasing concentrations of pure quartz particles (DQ) of three sizes (DQPM1, <1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm) and carbon black particles of two sizes (CB0.1, <0.1 μm; CB1, <1 μm) for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase (LDH) and cell viability. Nitric oxide (NO) generation and cytokines (TNF-α and IL-1β) releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay (ELISA), respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.

Size-dependent biological effects on vascular endothelial cells induced by different particulate matters / 华中科技大学学报（医学）（英德文版）

The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells (HUVECs) were exposed to increasing concentrations of pure quartz particles (DQ) of three sizes (DQPM1, <1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm) and carbon black particles of two sizes (CB0.1, <0.1 μm; CB1, <1 μm) for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase (LDH) and cell viability. Nitric oxide (NO) generation and cytokines (TNF-α and IL-1β) releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay (ELISA), respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.

The analysis of adverse health effects of occupational hazards factors in one solid waste landfill / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To determine occupational hazards in work sites of a large solid waste landfill and analyze their adverse health effects.</p><p><b>METHOD</b>The national standardized detection methods were used to determine dust concentration, harmful gas and physical factors in worksites. Routine physical examination, pulmonary function, hearing tests and nervous system test were performed in workers for 2 consecutive years. Urine lead, cadmium and mercury contents were detected. The comet assay was use to measure DNA damage in peripheral blood lymphocytes among workers.</p><p><b>RESULT</b>The main occupational hazard factors in this solid landfill are dust, harmful gas, high temperature and noise. The oxides, carbon monoxide, and noise and high temperatures in summer at some work sites exceeded the national occupational exposure limits. The prevalence of respiratory inflammation and rate of pulmonary function decrease among front-line workers and on-site technical managers are 21.2% and 11.5%, which are significantly higher than those among administrative staff (7.1% and 0) (P < 0.05). Nervous system abnormalities rate of front-line workers and on-site technical managers was 50.0%, which is significantly higher than that (26.7%) of administrative staff (P < 0.05). Because of long-term exposure to high intensity noice, hearing loss rate of bulldozer drivers was 10.3%. In addition, about 75% of workers with DNA damage in peripheral blood lymphocyte are front-line workers.</p><p><b>CONCLUSION</b>Adverse health effects from occupational hazards were observed among workers in this solid waste landfill.</p>

Smoking status or age impact on urinary 8-hydroxy-2'-deoxyguanosine in electrical and electronic equipment waste dismantling workers / 中华预防医学杂志

<p><b>OBJECTIVE</b>To investigate the smoking or age impact on occupational workers in electrical and electronic equipment waste (e-waste) dismantling procedure, using 8-Hydroxy-2'-deoxyguanosine (8-OHdG) in the urine as a biomarker for oxidative damage to DNA.</p><p><b>METHODS</b>The pre-workshift and post-workshift urinary samples of 64 male workers in e-waste dismantling procedure were detected by solid-phase extraction-high performance liquid chromatography-electrochemical detector (SPE-HPLC-ECD). The data were statistically analyzed by two factors, age or smoking status.</p><p><b>RESULTS</b>The 8-OHdG levels in non-smokers' urines (n = 42) were higher than those in smokers' urines (n = 22). The levels in pre-workshift urines were detected at (8.25 +/- 4.23) micromol/mol creatinine in non-smokers, while the values were (5.44 +/- 1.18) micromol/mol in smokers. And, the levels in post-workshift were detected at (43.12 +/- 16.19) micromol/mol creatinine in non-smokers, while the values were (14.82 +/- 2.51) micromol/mol in smokers. The 8-OHdG levels in pre-workshift urines were not different between non-smokers and smokers (t = -0.81, P = 0.42), however after 1 day exposure, urinary 8-OHdG levels were significantly increased in non-smokers than those in smokers (t = - 2.33, P < 0.05). On the other hand, the subjects were divided into five groups according to their age. The 8-OHdG levels in pre-workshift urines were (1.86 +/- 0.66), (3.57 +/- 0.54), (8.12 +/- 4.10), (11.39 +/- 3.70) micromol/mol creatinine in < 20 years group (n = 6), 20 -years group (n = 22), 30 - years group ( n = 23), 40 - 49 years group (n = 11) respectively. No effect of age was found on the pre-workshift urinary 8-OHdG levels (F = 0.98, t = 0.41). However, it was found that the post-workshift urinary 8-OHdG levels increased along with the e-waste workers' age (F = 4.81, P = 0.03), and they were (4.19 +/- 2.85), (19.89 +/- 5.26), (28.89 +/- 14.61), (34.94 +/- 12.50) micromol/mol creatinine in < 20 years group, 20 - years group, 30 - years group, 40 - 49 years group respectively.</p><p><b>CONCLUSION</b>The urinary 8-OHdG levels in the e-waste dismantling workers might be inhibited by smoking status. The post-workshift urinary 8-OHdG levels increased along with the e-waste workers' age.</p>

Clinical value of 24-hour ambulatory electrocardiography in childhood myocarditis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of 24-hr ambulatory electrocardiography (DCG) of children with myocarditis and to study the clinical value of DCG in the diagnosis of childhood myocarditis.</p><p><b>METHODS</b>24-hr DCG findings, including abnormal DCG rate, and number, grade and distribution of ventricular premature beat (PVC), as well as heart rate variability, from 59 children with myocarditis were retrospectively reviewed and compared with those detected in 41 children without heart disease.</p><p><b>RESULTS</b>86.4% of patients with myocarditis showed abnormal DCG, and compound arrhythmia was commonly seen, but only 46.3% showed abnormal DCG (P < 0.01) and single arrhythmia was predominant in the control group. The number and grade of PVC/24 hrs were not significantly different between the two groups. Compared with the control group, the average pattern PVC was predominant in the myocarditis group (84.6% vs 48.7%; P < 0.05). Monopeak pattern PVC was mostly seen (64.4%), followed by multiple-peak pattern (25.4%) and bi-peak pattern (8.4%) in the myocarditis group, which were significantly different from the control group: monopeak pattern 53.6%, bi-peak pattern 36.6% and multiple-peak pattern 7.3% (P < 0.01).</p><p><b>CONCLUSIONS</b>The 24-hr DCG characteristics of children with myocarditis are different from the normal controls, suggesting 24-hr DCG monitoring is useful to the diagnosis of childhood myocaditis.</p>