ABSTRACT
Objective To establish a method for measurement of 239Pu in fecal samples based on inductively coupled plasma-mass spectrometry (ICP-MS), and to provide a novel method for assessing the internal exposure of workers. Methods Fecal samples were collected from workers and labeled. The samples were pretreated with carbonization ashing and microwave digestion devices, purified on TEVA resin, and measured using ICP-MS. Results The detection limit of 239Pu in fecal samples based on ICP-MS was 1.91 × 10−4 Bq. Conclusion In the routine monitoring of class S substances characterized by a 5 μm aerodynamic diameter during 12 months, the committed effective dose corresponding to the detection limit is 0.17 mSv. This value meets the requirements of relevant national standards and ICP-MS can be used as a novel means for accurate evaluation of internal exposure for workers.
ABSTRACT
@#<b>Objective</b> To preliminarily study and establish a method for measurement of the transuranic nuclide <sup>241</sup>Am in fecal samples, and to provide technical support for internal radiation monitoring of staff. <b>Methods</b> Fecal samples were collected with a self-made stool sampler and treated with a self-made carbonization and ashing furnace. DGA resin was used to separate and purify <sup>241</sup>Am from fecal samples. With <sup>243</sup>Am as the tracer, the orthogonal method was used for condition optimization. <b>Results</b> The optimum conditions for separation and purification were: the acidity of HNO<sub>3</sub> added into the column, 6 mol/L; column flow rate, 0.6 mL/min; and the volume of analytical solution,12 mL. The method based on inductively coupled plasma mass spectrometry showed a detection limit of 9.79×10<sup>−4</sup> Bq for <sup>241</sup>Am in fecal samples, which was satisfactory and feasible. <b>Conclusion</b> This method fills the vacancy of <sup>241</sup>Am measurement in fecal samples to some extent, which is of practical significance for internal radiation monitoring and protection for analysts.
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Objective To study the effects of concentration of glucose on the proliferation of bone marrow mesenchymal stem cells (BMMSCs).Methods BMMSCs passaged to the 4th to 6th were inoculated and cultured.The control group was treated with DMEM/F12 (1∶1) standard medium,and the basal glucose concentration was 5.5 mmol/L.The experimental group was treated with DMEM/F12 (1∶1) high-glucose medium with the concentration of 20.5,25.5,30.5 and 35.5 mmol/L respectively,and continuously cultured for 15 d.The absorbance (A) values of each group once per day were measured by thiazolyl blue (MTT) colorimetry.Results Compared with the control group,the absorbance was increased at the 2nd,3rd,and 5th days in the 20.5 and 30.5 mmol/L groups,and the differences were statistically significant (all P＜0.05).For the 25.5 mmol/L group,the absorbance was increased at the 2nd,3rd,5th and 8th days,and the differences were statistically significant (all P＜0.05).For the 35.5 mmol/L group,the absorbance was increased at the 2nd,3rd,5th and 8th days and decreased at the 8th day,and the differences were statistically significant (all P＜0.05).The results of 20.5,25.5,30.5 and 35.5 mmol/L groups were further compared one another.The results showed that the absorbance at the 4th and 12th days in the 35.5 mmol/L group were lower than that of the 20.5 mmol/L group,and the differences were statistically significant (all P＜0.05).The absorbance at the 11th and 14th days in the 30.5 and 35.5 mmol/L groups were lower than that of the 20.5 mmol/L group,and the differences were statistically significant (all P＜0.05).Conclusions High-glucose environment can promote the proliferation of BMMSCs in a short time.However,with the prolongation of culture time,this effect is gradually weakened because of the inhibiting effect of high-glucose environment to the cell proliferation.