101 research outputs found
Fitting the grain orientation distribution of a polycrystalline material conditioned on a Laguerre tessellation
The description of distributions related to grain microstructure helps
physicists to understand the processes in materials and their properties. This
paper presents a general statistical methodology for the analysis of
crystallographic orientations of grains in a 3D Laguerre tessellation dataset
which represents the microstructure of a polycrystalline material. We introduce
complex stochastic models which may substitute expensive laboratory
experiments: conditional on the Laguerre tessellation, we suggest interaction
models for the distribution of cubic crystal lattice orientations, where the
interaction is between pairs of orientations for neighbouring grains in the
tessellation. We discuss parameter estimation and model comparison methods
based on maximum pseudolikelihood as well as graphical procedures for model
checking using simulations. Our methodology is applied for analysing a dataset
representing a nickel-titanium shape memory alloy
Histone Deacetylase Activity Modulates Alternative Splicing
There is increasing evidence to suggest that splicing decisions are largely made when the nascent RNA is still associated with chromatin. Here we demonstrate that activity of histone deacetylases (HDACs) influences splice site selection. Using splicing-sensitive microarrays, we identified ∼700 genes whose splicing was altered after HDAC inhibition. We provided evidence that HDAC inhibition induced histone H4 acetylation and increased RNA Polymerase II (Pol II) processivity along an alternatively spliced element. In addition, HDAC inhibition reduced co-transcriptional association of the splicing regulator SRp40 with the target fibronectin exon. We further showed that the depletion of HDAC1 had similar effect on fibronectin alternative splicing as global HDAC inhibition. Importantly, this effect was reversed upon expression of mouse HDAC1 but not a catalytically inactive mutant. These results provide a molecular insight into a complex modulation of splicing by HDACs and chromatin modifications
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