ABSTRACT
Abstract A method for determination of trace mercury in water was established. The trace mercury in water was adsorbed quantitatively by activated carbon, and then determined by electrical pyrolysis atomic absorption spectrometry. In comparison with the detection methods of total mercury in water at present, the method avoids the steps of digestion, reduces the mercury pollution and the loss of the mercury, and is simple in operation. The effects of particle size of activated carbon, acid treatment method, acid medium and enrichment time on the enrichment efficiency were investigated. The effect of the pyrolysis temperature and the interfering ions on the determination results was investigated. Three standard addition procedures including activated carbon blank addition, solution blank addition and environmental water samples addition were studied. Regression correlation coefficients of three standard curves drawn by the three methods reached 0 . 9999 . The slope of the three standard curves had no difference by statistical test, indicating that the determination of mercury in environmental water samples under the experiment conditions was not interfered by the coexistent elements, which showed that the activated carbon blank addition method could be directly used for preparing standard curve of the method. The water samples containing 5 ng/L and 50 ng/L mercury were determined by the method, and the relative standard deviation were 7. 2% and 4. 2% (n=11), respectively, with a detection limit of 1. 2 ng/L. The recovery experiment was carried out after adding 10 ng/L mercury to the surface water and tap water samples, and the recoveries were between 92. 0% and 103. 0%. Analysis results were compared with ICP-MS as control and the deviation of the two methods were between 2 . 9% and 3 . 4%, indicating that the method was accurate and reliable, and had good precision.
ABSTRACT
Objective:To investigate Intraflagellar Transport 80 (IFT80) protein expression in bone, lung, pancreatic, stomach, in-testinal, prostate, breast, and ovarian cancers to explore its mechanism in cancer cell proliferation and to diagnose and identify new tar-gets in cancer treatment. Methods:Immunohistochemistry was used to investigate the expression of IFT80 in gastric cancer tissue of different stages and in eight other kinds of human cancer tissues. We studied the relationship between cancer cell proliferation and inhi-bition of IFT80. Immunofluorescence method and cell culture were used to study the cilia and IFT80. Results:Results showed the fol-lowing:a) the expression of IFT80 was high in gastric and lung carcinoma tissues, moderate in breast and colorectal cancers, low in bone and ovarian cancers, and nearly absent in prostate and pancreatic cancers;b) inhibition of IFT80 in the A549 cancer cell line accel-erated cell proliferation and resulted in shorter, lower quality cilia;and c) IFT80 was abundantly expressed in cancer tissues of well-dif-ferentiated stage-IIA gastric cancer and normal gastric tissues, but was hardly expressed in late-stage, poorly differentiated gastric can-cer. IFT80 could have various degrees of expression in gastric carcinoma of other stages and differentiation. Conclusions:Different can-cer organs showed variation in IFT80 expression. IFT80 can be distributed in the organs with mechanical motion function, such as lungs and stomach. IFT80 is distributed on the cell cilia and can adjust the number and length of the cilia by reducing IFT80 protein ex-pression. Through a variety of ways, IFT80 directly or indirectly participates in the proliferation of cancer cells. Thus, the lowest or nearly zero expression of IFT80 can be seen in cancer tissues of high-grade malignancy, such as advanced cancers with poor differentia-tion.