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Objective We set up an uncertainty assessment method for determination of iodides in water by As3+-Ce4+ catalytic spectrophotometry, in order to assess the accuracy of the method and the major influencing factors, and to build up an equation to assess the uncertainty in the mobility of working curve and an uncertainty assessment method for pipettors.Methods According to Methods for Water Iodine Detection Suitable for Iodine Deficiency and Iodine Excess Areas, the uncertainty items of the two standard materials (GBW09114c and GBW09113c) in different concentrations, such as repeatability of measurement, the mobility of working curve, the uncertainty of standard solution and sample solution, etc, were analyzed.Results The contents of iodide in GBW09114c and GBW09113c were (61.3 ± 1.4) and (8.1 ± 0.3)μg/L;relative expanded uncertainty RU1 and RU2 were 2.25％ and 3.46％, both of them were in the range of acceptable deviation in the standard material certification (10.0％ and 14.8％).Major influencing factors were repeatability of measurement, the uncertainty of standard solution (including the uncertainty of potassium iodide reference reagent and glass equipment), and the uncertainty of sample solution (including the uncertainty of pipettors).A more adaptable equation for the mobility of working curve had been proposed;the factors involved in environment temperature and operation repeatability were used as the items of the pipettors' uncertainty.Conclusion This method can be used to assess the uncertainty in determination of water iodides by As3+-Ce4+ catalytic spectrophotometry.
RESUMO
Objective To evaluate the effect of slow-release microcapsules of HCF( hepatocyte growth factor) on angiogenesis in infracted myocardium.Method Myocardial infarction was induced in 30 New Zealand rabbits by ligating the middle of left descending coronary artery. Group Ⅰ ( n = 10) was served as a control group, group Ⅱ ( n =10) as a blank microcapsule group, group Ⅲ ( n = 10) as experimental group with each microcapsule contains 1 μgHGF as HCF group. In group Ⅱ andⅢ, 5 blank microcapsules or FGF slow-release microcapsules were implanted into myocardium under epicedium between the left descending coronary artery and left circumflex branch. The heart function of each rabbit was evaluated with echocar-diography and cheterization, angiogenesis was evaluated by immunohistochemical technique 6 weeks later.Result As compared with group Ⅰ and Ⅱ , rabbits treated with HGF had higher microvessel counts ( P < 0. 01), and LVFS and EF were significantly increased [ (101. 28±19. 50,105. 28 ±18. 28,161. 28 ±15. 85, P <0.01 ]. Conclusion Subepicardial implantation of HGF slow release microcapsule in the infracted rabbit model can enhance effective angiogenesis and improve left ventricular function.