The aim of this study was to determine the capacity of the meiotic spindle (MS) to predict embryo implantation and live birth rates. For this purpose, we performed a broad systematic literature search. Of all publications retrieved, only those in which the implantation rates were related to some characteristics of the MS were evaluated. Despite the different methodology used in all the chosen studies, presence of the MS in oocytes was found to be positively associated with embryo implantation. Moreover, high retardance values, as well as strict criteria of normality in the MS structure, are significantly related to higher embryo implantation numbers and live birth rates.

Deposition of calcium carbonate from groundwater was examined on a moss, Didymodon tophaceus, from a Niagara Escarpment waterfall. A spectrophotometer on a polarizing microscope was used for interferometry. A second-order blue interference with an interference minimum around 620 nm was found when moss cell spaces were fully calcified. Filled cell spaces were often surrounded by empty cell spaces. Complete calcification of whole leaflets resulted in progressively higher orders of interference colors and a positive shift in interference minima. Calcified leaflets finally became cemented together, but each retained a weak extinction when rotated. Small calcareous spherulites (mean diameter 15.7 ± 2.1 μm) were found between leaflets. Spherulites exhibited first-order white interference with a Maltese cross that rotated when the polarizer and analyzer were rotated in tandem. A Nikitin-Berek compensator was tilted at 5.5° to give an interference minimum at 600 nm in the optical axis. Quadrants of spherulites with radii more or less in line with the tilting axis of the compensator had lower (P < 0.001) interference minima (535 ± 27 nm) than quadrants with radii more or less perpendicular to the compensator (659 ± 15 nm), thus indicating a radial internal structure. Spherulites were tentatively identified as vaterite.