On-Off Ratiometric Fluorescence Europium(III) Metal-Organic Framework for Quantitative Detection of the Inflammatory Marker Neopterin.

Benefiting from the unique photoluminescence behavior of the lanthanide(III) ions and organic ligands, a lanthanide(III) metal-organic framework (Ln-MOF) material can simultaneously demonstrate photoluminescence of lanthanide(III) cations and organic molecules and endow its superior applications of fluorescence sensing behaviors. Herein, we present a europium(III) MOF material {[Eu2(BPTA)·(CH3COO)2·3DMA]·0.5DMA·3H2O}n (1) (where H4BPTA is 3,3',5,5'-biphenyltetracarboxylic acid) for photoluminescence performance of quantitatively sensing the inflammatory marker neopterin (Neo). The obtained 1 comprises Eu2(COO)4 paddlewheel secondary building units, which could be bridged by BPTA4- ligands to extend a 2D framework. The fluorescence titration indicates 1 can achieve simultaneous fluorescence behavior of Eu3+ ions and Neo via on-off ratiometric effects and thus could be exploited as the ratiometric fluorescence sensor matrix. Such a fluorescence phenomenon of 1 as a ratiometric sensor for quantitative detection of Neo via an on-off ratiometric effect is never observed in MOF chemistry. Moreover, naked-eye visible color variations of the fluorescence for 1 could be observed from red to blue with increasing concentrations of Neo, confirmed by fluorescent test strips as well as portable fluorescent hydrogels. And 1 also shows a low detection limit of 15.11 nM. A synergetic contribution of the competitive absorption, fluorescence resonance energy-transfer, and photoinduced electron-transfer mechanisms between Neo and the framework of 1 realizes the on-off ratiometric fluorescence behavior for Neo detection, supported by the UV-vis spectral overlap experiment and DFT calculations.

Two luminescent lanthanide(iii) metal-organic frameworks as chemosensors for high-efficiency recognition of Cr(vi) anions in aqueous solution.

Two new lanthanide(iii) metal-organic frameworks (MOFs) {[(CH3)2NH2]2[Ln4(FDA)7(DMF)2]·0.5DMF}n [Ln = Eu (1), and Tb (2)] based on furan-2,5-dicarboxylic acid (H2FDA) have been successfully assembled and well characterized in detail. These MOFs are isostructural and demonstrate 12-connected sqc15 topologies, which are rarely observed in MOF chemistry, especially in lanthanide(iii) MOFs. Moreover, these two MOFs could show a tolerance towards moisture and organic solvents and satisfactory chemical stabilities. More importantly, they exhibit sensitive and selective luminescence quenching response towards Cr2O72- and CrO42- anions in aqueous solution with the average quenching Ksv values of 1.25 × 104 L mol-1 (Cr2O72-) and 3.56 × 103 L mol-1 (CrO42-) for 1 and 1.46 × 104 L mol-1 (Cr2O72-) and 4.35 × 103 L mol-1 (CrO42-) for 2 and the detection limits of 1.14 × 10-4 mol L-1 (Cr2O72-) and 1.12 × 10-4 mol L-1 (CrO42-) for 1 and 7.42 × 10-5 mol L-1 (Cr2O72-) and 1.27 × 10-4 mol L-1 (CrO42-) for 2. The high quenching Ksv values and low detection limits make them more feasible in sensing Cr(vi) anions in aqueous solution. The possible detection mechanism has been discussed in detail.

Size-dependent biological effects on vascular endothelial cells induced by different particulate matters.

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-1ß) 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 study of the characteristics and influencing factors of pneumoconiosis among workers exposed to dusts in an iron mine].

OBJECTIVE: To analyze the prevalence characteristics and influence factors of pneumoconiosis of workers exposed to dusts in an iron mine, to provide the base of preventive measures for pneumoconiosis of iron mine. METHODS: The subjects of cohort study were all workers exposed to dusts for at least one year registered in an iron mine during 1960 to 1974, and followed-up to the end in 2003. The cases with pneumoconiosis were diagnosed by the local diagnosis group of pneumoconiosis, according to the national diagnostic criteria of pneumoconiosis. The risk factors were analyzed with Cox risk model. RESULTS: A total of 3647 miners were included in the cohort study and were followed up by 132 574.4 person years. There were 316 cases with pneumoconiosis, and the incidence of pneumoconiosis for a year was 0.24 per thousand. There were 274 cases (86.7%) with pneumoconiosis in workers exposed to dusts before 1960, the incidence of pneumoconiosis for a year was 0.40 per thousand, which was significantly higher than that (0.07 per thousand) of workers exposed to dusts after 1960. The average latency of pneumoconiosis was 26.0 +/- 7.3 years. The average durations of upgrade from stage 0(+) to I , I to II and II to III were 5.3 +/- 3.2, 6.6 +/- 5.2 and 11.3 +/- 5.0 years, respectively. However, 164 cases with pneumoconiosis were diagnosed after ceasing exposure to dusts for mean 8.3 years. The risk of pneumoconiosis in iron miners increased with exposure doses, and there was an obvious dose-effect relationship. The average cumulative exposure dose of cases with pneumoconiosis was 173.7 +/- 91.6 mg/m3 x y, which was significantly higher than that (112.1 +/- 64.8 mg/m3 x y) of workers without pneumoconiosis. Also the tuberculosis (HR = 5.9, P < 0.001) and smoking (HR = 1.7, P < 0.01) were the main risk factors. CONCLUSION: There was an obvious dose-effect relationship between the cumulative exposure dose and pneumoconiosis incidence. Tuberculosis and smoking were the main risk factors influencing the pneumoconiosis incidence.

[The analysis of adverse health effects of occupational hazards factors in one solid waste landfill].

OBJECTIVE: To determine occupational hazards in work sites of a large solid waste landfill and analyze their adverse health effects. METHOD: 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. RESULT: 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. CONCLUSION: Adverse health effects from occupational hazards were observed among workers in this solid waste landfill.

[Study on the injury of vascular endothelial cells affected by dust particles from workplaces in pottery factories and tungsten mines].

OBJECTIVE: to assess direct adverse effects of occupational dusts from pottery factories and tungsten mines on vascular endothelial cells in vitro test. METHODS: human umbilical vein endothelial cell (HUVEC) line HUV-EC-C were used as target cells. HUVEC were then treated with respirable dust particles from workplaces in pottery factories and tungsten mines in concentrations of 25, 50, 100, 200 and 400 microg/ml for 24 h. Standard quartz was used as control. LDH activity, cell viability, the release of NO and TNF-α levels were determined to assess the biological responses of the dust particles. RESULTS: dose-response relationships between the dust concentrations and the enhancement of the LDH activity, the release of NO and TNF-α were found in both dust particles from pottery factories and tungsten mines. The cell viability decreased with the increase of dust concentration from 25 to 400 microg/ml. Compared with the dust particles from workplaces, the quartz dust induced significantly higher LDH activity (P < 0.05) after cultured with HUVEC. No significant difference of releases of NO were observed among the dust particles from workplaces and standard quartz. However, significantly higher levels of TNF-α were induced by standard quartz compared with dust samples from workplaces at concentrations of 200, 400 microg/ml. CONCLUSION: occupational dust particles from workplaces and quartz could induce the injury and the releases of TNF-α from HUVEC.

[Effect of humidity and temperature on filter and gravimetric measurement of ambient particulate matter in a balance room].

OBJECTIVE: To assess the effects of the alteration of humidity and (or) temperature on weight of filters without and with ambient particulate matter in a balance room. METHODS: The mass of blank dust sampling filters were weighed under (18 +/- 1) degrees C and (28 +/- 1) degrees C respectively, with the humidity varying from 35% relative humidity (RH) to 100% RH in a balance room. Then the blank filters were divided into two groups and were used to sample total dust and respirable dust. After sampling, the loaded filters were re-weighed under above conditions and the mass difference before and after the sampling were compared and analyzed. RESULTS: The vibration of the average mass of filters varied from 0.10 to 0.13 mg and from 0.06 to 0.09 mg under the temperatures of (18 +/- 1) degrees C and (28 +/- 1) degrees C respectively; When both the temperature and humidity changed, it varied from 0.12 to 0.16 mg. The deviation of average mass difference ranged from 0.07 to 0.10 mg and from 0.04 to 0.08 mg under the two temperatures mentioned above; When both the temperature and humidity changed, it varied from 0.09 to 0.14 mg. The average mass of blank filters and loaded filters were all positively correlated with the change of humidity (P < 0.01). No effects of humidity on the average mass difference of the loaded filters were observed. The average mass differences of loaded filters and blank filters under (18 +/- 1) degrees C were significantly higher than that under (28 +/- 1) degrees C (P < 0.01) when humidity was not changed. CONCLUSION: The alteration of humidity and (or) temperature in a balance room attributes to the deviation of the measurement of the mass of filters and thus affects the gravimetric measurements of ambient particulate matter.

[A test of screening to predict lung cancer among dust-exposed tin miners with sputum imaging cytometry].

OBJECTIVE: To evaluate efficacy of sputum imaging cytometry in early diagnosis on lung cancer among tin miners exposed to dust and analyze possible risk factors related to lung cancer among tin miners. METHODS: From a cohort of tin miners in Guangxi Province, a total of 345 male tin miners higher than 45 years old and with high exposure to crystalline silica dust were randomly selected as the objects. Imaging cytometry was used to implement the sputum analysis for the screening on lung cancer according to the experience diagnostic standard. All objects were then followed up to the end of 2006. Clinical diagnosis of lung cancer was used as the golden standard to evaluate the efficacy of screening. RESULTS: From 1998 to 2006, 11 new cases were diagnosed as clinical lung cancer. Except of age and exposure to occupational hazards, smoking status (P = 0.0384) and mean smoking dose (P = 0.0078) were significantly associated with lung cancer, and the adjusted odds ratio of high level to the low was 18.21 (2.15 approximately 154.39). The sensitivity, specificity and Youden's index of the sputum imaging cytometry for the experience diagnosis were 27.3%, 83.9% and 11.2% respectively. According to the ROC curve analysis, area under ROC Curve (AUC) of C2.5 (the percentage when the DNA index ranged from 1.25 to 2.50) was 0.647 (0.525 approximately 0.768), with the optimal operating point (OOP) of 1.70%. Sensitivity, specificity, agreement rate, positive predictive value, negative predictive value and Youden's index for predicting lung cancers in high-exposure tin miners were found to be 72.7%, 62.3%, 62.6%, 6.0%, 98.6% and 35.0% respectively. CONCLUSION: Smoking is confirmed as an important risk factor of lung cancer in tin miners. The diagnostic efficiency can be improved if the diagnostic point of C2.5 is adjusted to 1.70%.

[Mortality analyses for tungsten miners].

OBJECTIVE: To investigate the mortality from main causes of death in 6 tungsten miners and explore the effects of cumulative dust exposure on standardized mortality ratios (SMRs) from main causes. METHODS: A cohort of 18027 workers registered in the employment record from 6 tungsten mines located in Hunan and Jiangxi province and working for at least 1 year was identified for this study. SMRs were calculated based on Chinese national mortality. Trend analysis was used to analyze the effect of cumulative dust exposure on SMRs of main causes of death. RESULTS: The cohort was followed up from 1972 to 2003 with an accumulative of 470 722.21 person-years. A total of 6135 workers died, and the mortality was 13.03 per thousand. Cardiovascular disease, respiratory disease, malignant neoplasm and pulmonary tuberculosis accounted for 79.32% of all death. The mortalities of all-causes, pneumoconiosis, pulmonary tuberculosis, nasopharyngeal carcinoma, infectious disease, respiratory disease, cardiovascular disease and liver cancer were found to be significantly higher than the national average level. Positive dose-response relationship between SMRs and cumulative dust exposure was observed in all-causes, pneumoconiosis, pulmonary tuberculosis, respiratory disease, cardiovascular disease (P < 0.01). CONCLUSION: The mortality from main causes of death for the dust-exposed workers are higher than that for non dust-exposed workers. Positive dose-response relationships are observed between cumulative dust exposure and SMRs from all-causes, respiratory disease (including silicosis), pulmonary tuberculosis and cardiovascular disease.