Fig. 2.

Representative SEM images of crystals extracted from rat urine. The group the crystals were extracted from is indicated in parentheses, but similar features were observed for all the regular water (a – c) or all the ethylene glycol water (d – e) groups. (a & b) Large struvite crystals were prevalent (thick arrows). EDS (inset) shows the expected peaks for struvite of N, Mg, P, O, along with K, which occurs in the potassium magnesium phosphate form (KMg(PO4)•6H2O), as well as C (presumably from organic matter). The crystals were well faceted, but had a rough surface texture that appears to be a coating of some sort, as evidenced by the cracks that can be seen in the coating (such as just above the arrow on the right, vertically oriented crystal). There are small clusters of amorphous mineral or organic granules in background (thin arrow), similar to those seen in the higher mag. image of (c), which seem to suggest that these amorphous particles (possibly formed during drying) attached to form the coating on the large crystals (BRP-C). (c) Clusters of granular precipitates with non-descript morphologies, suggesting they were or may still be amorphous at this point (BRP-C). (d) Large granular precipitate. Fragments of BRPs were occasionally observed in the urine that seemed to have dislodged from the implants, so these may be from such fragments, or they may have created favorable substrates for continued mineral accumulation (BRP-OPN). (e) Spherical cluster of COM crystals which appear to be heavily twinned (thick arrow), along with a multitude of small COD crystals (arrow head) in background (BRP-DNM). (f) Agglomerate of COD crystals (thick arrow) containing some smooth and non-descript material, alongside smaller COD and COM (arrowhead) crystals in background. The fibrous strand (thin arrow) suggests this agglomerate originated from some dislodged implant material (BRP-PA). Scale bars are as follows: (a) 10 μm, (b) 10 μm, (c) 2 μm, (d) 10 μm, (e) 5 μm, (f) 10 μm