Silk fibroin (SF) and fiber alignment were introduced into polycaprolactone (PCL)-based electrospun nanofibers as chemical and physical cues for tendon tissue engineering applications. The physicochemical properties of random PCL (RP) nanofibers, random PCL/SF (RPSF) nanofibers and aligned PCL/SF (APSF) nanofibers were characterized for fiber orientation and SF blending effects. An in vitro cell culture with rabbit dermal fibroblasts (RDFBs) on nanofibers indicated that SF promotes cell proliferation to a higher extent than fiber alignment. Cells aligned in the direction of fiber axes could be confirmed through scanning electron microscopy (SEM) observation and cytoskeleton staining. The quantitative real-time polymerase chain reaction (qRT-PCR) experiments indicated up-regulated gene expression of tendon marker proteins (type I collagen (Col I), fibronectin and biglycan) on APSF nanofibers and tendon reconstruction was confirmed from Col III gene expression. Animal experiments with Achilles tendon defect repairs in rabbits were carried out with RPSF and APSF scaffolds. The beneficial effects of fiber alignment were verified from histological and immunohistochemical staining, where cell migration and extracellular matrix protein deposition tend to stretch in a parallel direction along the axial direction of APSF nanofibers with enhanced Col I and tenascin C production. Biomechanical testing indicated the tensile stiffness and maximum load of cell-seeded APSF scaffolds were 60.2 and 81.3% of normal tendon values, respectively, which are significantly higher than cell-seeded RPSF or acellular APSF and RPSF scaffolds. These results suggest that APSF nanofiber scaffolds combined with RDFBs have the potential to repair the gap defects of Achilles tendons in vivo and to effectively restore the function and structure of tendons.

We report high‐precision cadmium isotope ratios for a series of standard solutions and geological reference materials for interlaboratory comparison. Complete separation of Cd from a matrix in geological samples was achieved using AG MP‐1M anion exchange resin with > 97.8% recovery. Cadmium isotope ratios were measured by both Neptune plus multi‐collector‐inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) and Nu Plasma II MC‐ICP‐MS at low‐resolution mode. Both sample calibrator bracketing (SSB) and double‐spike techniques (DS) were utilised for mass bias correction. Cadmium isotope ratio data of standard solutions (BAM I012 Cd, SPEX Cd, Alfa Aesar Cd, GSB Cd) and geological reference materials (GSS‐1, GXR‐1, GXR‐2, GSD‐12, NIST SRM 2711a) are reported relative to Cd solution (NIST SRM 3108). The intermediate precision over a three‐year period was better than ± 0.09‰ (2s) for δ114Cd/110Cd and ± 0.06‰ (2s) for δ112Cd/110Cd ratios. SPEX Cd was used as a secondary reference material for Cd isotopic measurement with a δ114/110CdNIST SRM 3108 value of −2.13 ± 0.09‰ (2s). The soil reference material NIST SRM 2711a has a significantly heavier isotopic composition than other soil materials, GXR‐1, GXR‐2 and GSS‐1. New recommended values are presented for future interlaboratory calibration.

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A Cu-rich mantle source may play a key role in generating giant magmatic Ni-Cu deposits worldwide, but evidence for source's Cu enrichment and its mechanism is still rare. Copper isotopes can provide novel and direct insights into this issue since metasomatism that causes Cu enrichment in the mantle is commonly associated with a huge Cu isotope fractionation. Here we present the first Cu isotopic study on the world-class Jinchuan magmatic Ni-Cu deposit in China, including disseminated, net-textured and massive sulfides. The disseminated and net-textured sulfides have variable δ 65 Cu values (+0.36 ± 0.38‰, n=42), which are higher than those of massive sulfides (−0.44 ± 0.28‰, n=11). The country rocks have a narrow This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America.The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

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