Developmental expression of COE across the Metazoa supports a conserved role in neuronal cell-type specification and mesodermal development

The transcription factor COE (collier/olfactory-1/early B cell factor) is an unusual basic helix–loop–helix transcription factor as it lacks a basic domain and is maintained as a single copy gene in the genomes of all currently analysed non-vertebrate Metazoan genomes. Given the unique features of the COE gene, its proposed ancestral role in the specification of chemosensory neurons and the wealth of functional data from vertebrates and Drosophila, the evolutionary history of the COE gene can be readily investigated. We have examined the ways in which COE expression has diversified among the Metazoa by analysing its expression from representatives of four disparate invertebrate phyla: Ctenophora (Mnemiopsis leidyi); Mollusca (Haliotis asinina); Annelida (Capitella teleta and Chaetopterus) and Echinodermata (Strongylocentrotus purpuratus). In addition, we have studied COE function with knockdown experiments in S. purpuratus, which indicate that COE is likely to be involved in repressing serotonergic cell fate in the apical ganglion of dipleurula larvae. These analyses suggest that COE has played an important role in the evolution of ectodermally derived tissues (likely primarily nervous tissues) and mesodermally derived tissues. Our results provide a broad evolutionary foundation from which further studies aimed at the functional characterisation and evolution of COE can be investigated

Optical and thermal properties of spinel with revised (increased) absorption at 4 to 5 mu m wavelengths and comparison with sapphire

Infrared absorption of high-quality, commercial, polycrystalline MgAl2O4 spinel is similar to 40% greater in the range of 3.8 to 5.0 mu m than the value predicted by the computer code OPTIMATR (R), which has been used for window and dome design for more than 20 years. As a result, spinel and a-plane sapphire windows designed to support the same external pressure with the same probability of survival have approximately the same infrared absorptance in the range 3.8 to 5.0 mu m. c-Plane sapphire has greater absorptance than spinel in the range 3.8 to 5.0 mu m. Spinel has two weak absorption bands near 1.8 and 3.0 mu m. At 1.064 mu m, the laser calorimetric absorption coefficient of spinel is 10 to 50 times greater than that of sapphire. New measurements of specific heat capacity, thermal expansion, thermal conductivity, elastic constants, and refractive index (including dn/dT) of spinel are reported. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI