Sample of a porous titanium alloy rod and gross specimens at 3 months after treatment.

<p>Blue arrowheads indicate treatment sites.</p

Schematic illustration of experimental design.

<p>Schematic illustration of experimental design.</p

Quantitative analysis of the parameters for reconstructed trabeculae, as calculated by micro-CT.

<p>Quantitative analysis of the parameters for reconstructed trabeculae, as calculated by micro-CT.</p

Lateral radiographic images of the ankle at different times.

<p>White arrowheads indicate osteolytic changes inside the talus, and white triangles indicate titanium rods.</p

Characteristics of the porous titanium alloy.

<p>Characteristics of the porous titanium alloy.</p

Section design for histology.

<p>Sections A, B, and C were prepared for staining.</p

The 3-D reconstruction of talar specimens performed by micro-CT.

<p>Quantitative study showed that the trabecular reconstruction of the IM group was prior to that of the DC group at each time point.</p

Histological examination of the DC and IM groups.

<p>The sections showed that the trabecular reconstruction was remarkable mainly in the IM group at 3 months after treatment, and the combination of the trabeculae and titanium alloy was very tight (Van Gieson stain, original magnification: left ×16; right ×100).</p

Percentages of reconstructed trabeculae in the ROIs of the two groups by histological study (<i>n</i> = 6, x ± s).

<p>Percentages of reconstructed trabeculae in the ROIs of the two groups by histological study (<i>n</i> = 6, x ± s).</p

Accurate Determination of Silver Isotopic Composition in Silicate Rocks with Low Silver Abundance

Owing to the extremely low abundance of silver in the Earth’s crust and mantle, it remains a major challenge to eliminate matrix impurities to obtain accurate silver isotopic compositions in silicate rocks. To determine precise and accurate silver isotopic data in silicates, we have modified the traditional pretreatment procedures, assessed isobaric interference and matrix effects, and analyzed silver isotopic compositions in silicates. By modification of the silicate digestion and ion-exchange procedures, efficient elution of silver was achieved. The doping experimental results indicated that the matrix effect induced by Ti and Cr could be satisfactorily corrected using the internal standard Pd isotope pair of 108Pd–106Pd. The modified chemical chromatographic method effectively separates Ni from Ag in silicate samples, thereby minimizing the significant isobaric interference from Ni cations. As a result, the shifts in the δ109Ag value caused by cations can be corrected to less than 0.02‰. There are considerable shifts down to −0.82‰ in δ109Ag from the accepted δ109Ag value when soluble metasilicate is present in the solution, which might explain the discrepancies in measured δ109Ag values for silicate materials. To accurately analyze silver isotopic compositions, especially of silicates with extremely low silver abundance, a silver standard doping method with an optimum doping proportion (sample-to-standard material ratio of 2:8) has been shown to produce an acceptable measurement uncertainty from 0.04 to 0.06‰ (2SD). The high-precision δ109Ag value determined in this study for ultramafic rocks from Balmuccia and the basalt reference material, BHVO-2, of −0.044 ± 0.062‰ is consistent with that of −0.16 ± 0.07‰ reported by previous studies. Our study paves the way for the more extensive use of silver isotopes in studies of terrestrial/extraterrestrial rocks, something that will be of help in constraining the sources of precious metals in polymetallic ore deposits as well as core formation and volatile-element depletion in the early solar system