Javier Herrero | Search arXiv

arXiv2026

Phase-selective growth of water-soluble strontium aluminate via sputtering deposition for freestanding oxide membranes

We report the epitaxial growth of high-quality water-soluble strontium aluminate films via sputtering deposition. We systematically investigate the dependence of the films structural quality on the growth conditions and we show that we can selectively grow, using the same target, both the cubic Sr3Al2O6 and the tetragonal Sr4Al2O7 phases by varying the atmosphere during growth. Using these water-soluble sacrificial layers we then synthesize ferromagnetic freestanding Sm2NiMnO6 membranes. By means of X-ray diffraction, synchrotron spectroscopic techniques and SQUID magnetometry, we demonstrate that our freestanding films exhibit properties comparable to epitaxial films.

cond-mat.mtrl-sci↗

arXiv2017

Quantification of tumour evolution and heterogeneity via Bayesian epiallele detection

Motivation: Epigenetic heterogeneity within a tumour can play an important role in tumour evolution and the emergence of resistance to treatment. It is increasingly recognised that the study of DNA methylation (DNAm) patterns along the genome -- so-called `epialleles' -- offers greater insight into epigenetic dynamics than conventional analyses which examine DNAm marks individually. Results: We have developed a Bayesian model to infer which epialleles are present in multiple regions of the same tumour. We apply our method to reduced representation bisulfite sequencing (RRBS) data from multiple regions of one lung cancer tumour and a matched normal sample. The model borrows information from all tumour regions to leverage greater statistical power. The total number of epialleles, the epiallele DNAm patterns, and a noise hyperparameter are all automatically inferred from the data. Uncertainty as to which epiallele an observed sequencing read originated from is explicitly incorporated by marginalising over the appropriate posterior densities. The degree to which tumour samples are contaminated with normal tissue can be estimated and corrected for. By tracing the distribution of epialleles throughout the tumour we can infer the phylogenetic history of the tumour, identify epialleles that differ between normal and cancer tissue, and define a measure of global epigenetic disorder.

q-bio.QM↗