Figure 2 The 176 Hf/ 177 Hf isotopic measurements for a mixed standard solution of which concentrations were 298.7 ng ml -1 for JMC 14375 Hf, 30.4 ng ml -1 for Accu-Trace Yb and 3.0 ng ml -1 for Accu-Trace Lu. Accu-Trace Lu
The β(Hf) and β Yb) values were measured by monitoring 179Hf/177Hf and 172Yb/173Yb ratios for a mixed standard solution of which concentrations were 298.7 ng ml-1 for JMC 14375 Hf, 30.4 ng ml-1 for Accu-Trace Yb (lot no. B4035064-2B, reference standard) and 3.0 ng ml-1 for Accu-Trace Lu (lot no. B8045141, reference standard).
Figure 3 Relation between the Hf and Yb mass bias factors ( β (Hf) and β (Yb)) for the same mixed standard solution as that described in Figure 2. We further tested the validity of isobaric interference correction described above by using Hf+Yb+Lu solutions mixed with different elemental proportions (Hf = 300 ng ml-1 JMC 14375, Hf Yb Lu ≈ 200 10 1, 100 10 1, 50 10 1, 30 9 1).
Figure 2 Isotope plot obtained during measurements of the samples using δ6XZn= [((6XZn/64Zn)sample / 6XZn/64Zn Lyon JMC 3-0749L)- 1] * 1000 (in ‰).
We have detected no difference in 5-bromodeoxyuridine uptake between primary cultures with different Pax6 dosages, and very little cell proliferation is noted in the first 2 h after wounding (Kitazawa et al [ 65]; JMC, unpublished observations), whereas Pax6+/+ cells, and Pax6+/- cells with exogenous EGF, begin to migrate within the first few minutes.
Solid and dashed lines respectively represent the average 176Hf/177Hf of JMC 14375 and 2σ S. D. on the mean for the unspiked solution.
Nb2O5 (>99 %, JMC) and NbCl5 (99.8 %, Acros) were mixed in a molar ratio of 1 3, sealed in Pyrex tubes, heated to 400 °C over 4 h, and kept at this temperature for 40 h.
It is also commonly planted in parks and there are introduced populations in other parts of Australia (e.g. Adelaide and Melbourne), as well as in New Zealand [ 31], Hawaii [ 32], California and Mediterranean Europe (JMC, pers. obs).
The 176Hf/177Hf ratio of this standard solution (300 ng ml-1 Hf), measured with the same analytical design as that for the measurement of JMC 475 standard solution (20 cycles, 4.194 s integration) gave an average of 0.282228±0.000005 (n=10, 2σ S. E). (Table 3).
The basic instrumental capability of the KBSI Neptune MC-ICP-MS was tested by using a JMC 475 Hf standard solution with a concentration of 200 ng ml-1.
We also measured Hf isotope ratios of in-house standard solution JMC 14375, delivered from Alfa Aesar of Johnson Matthey Company (stock no. 14375, lot no. 83-084740F, plastandarddard solution).
