2 research outputs found
New protocol based on massive parallel sequencing for aneuploidy screening of preimplantation human embryos
<p>Novel next-generation sequencing procedures have rapidly emerged into the preimplantation genetic screening framework. This work presents the design and validation of a new low-coverage whole-genome sequencing assay for aneuploidy detection in single blastomeres and trophectodermal samples from preimplantation embryos. The validation ensures analytical sensitivity, specificity, robustness, precision, limit of detection, resolution, and reproducibility. Specific parameters to measure the performance are defined, and the results are compared with a standardized array-based method to stablish the concordance. From the single cell genomics point of view, the main novelties are the length of reads of the libraries (150 nucleotides) together with a paired-end strategy and the design of an original algorithm and copy number viewer. A total of 129 samples were included in six experimental runs using a MiSeq Illumina platform. Samples included: single amniocytes, single blastomeres (cleavage-stage embryos), trophectoderm samples (blastocyst), and diluted DNA. Sensitivity and specificity were calculated per chromosome yielding 96% and 99%, respectively. The percentage of concordant samples was 98.2% and all of the aneuploid samples were confirmed. In conclusion, the validation yields highly reliable and reproducible results, representing an accurate and cost-effective strategy for the routine detection of aneuploidy in human embryos.</p
Synthesis of CaNb<sub>2</sub>O<sub>6</sub> with a Rynersonite-like Structure: Morphology, Rietveld Refinement, Optical, and Vibrational Properties
In this study, we report the easy and low-cost synthesis
of calcium
niobate (CaNb2O6) with the isomorphic structure
of the Rynersonite mineral for CaTa2O6. The
samples were prepared by the ball milling method at room temperature
at a synthesis time of 0.5, 1, 2, 3, and 4 h. The structural analysis
by XRD, Rietveld refinement, and vibrational Raman spectroscopy confirms
all diffraction peaks and active mode characteristics of the pure
phase of CaNb2O6 for the 3-h and 4-h samples,
with a crystallite size of 22.5 and 23.2 nm, respectively. The optical
band gap obtained was 3.18(2) eV (3-h sample), lower than the optical
band gap for niobium oxide, characteristic of materials with strong
photon absorption in the UVA region of the spectrum. The surface analysis
by scanning electron microscopy reveals the obtention of several agglomerates
of irregular particles ranging in the submicro and micro scales. Therefore,
the present approach successfully obtained calcium niobate with the
formula CaNb2O6 at a short synthesis time and
room temperature