Discovery of 505-million-year old chitin in the basal demosponge Vauxia gracilenta

Sponges are probably the earliest branching animals, and their fossil record dates back to the Precambrian. Identifying their skeletal structure and composition is thus a crucial step in improving our understanding of the early evolution of metazoans. Here, we present the discovery of 505-million-year-old chitin, found in exceptionally well preserved Vauxia gracilenta sponges from the Middle Cambrian Burgess Shale. Our new findings indicate that, given the right fossilization conditions, chitin is stable for much longer than previously suspected. The preservation of chitin in these fossils opens new avenues for research into other ancient fossil groups

Fullerite C60 optical constants in the C 1s NEXAFS region

Using data on the absorption cross sections the refraction coefficient spectral dependence n E and the spectra of the remaining optical coefficients reflection coefficient, phase shift, and atomic form factor in the fullerite C60 C 1s near edge X ray absorption fine structure NEXAFS region 280 350 eV were determined. For the n E calculations the Kramers Kronig integral relations KKRs were used. The KKR computations were performed using data on atomic carbon absorption cross sections in the 10 30000 eV range and on solid and gaseous C60 in the 0 120 eV. Absorption cross section spectrum in the fullerite C60 C 1s NEXAFS region were measure

The Formation of Nanoscale Closed Graphene Surfaces during Fullerite C 60 Hot Isostatic Pressing

The fullerite C60 modified by hot isostatic pressing HIP at 0.1 GPa in argon near and beyond its thermal stability region 920 1270 K temperature interval was studied by X ray diffractometry, Raman spectroscopy, ultra soft X ray photoelectron and near edge X ray absorption fine structure spectroscopy. It was found that the C60 molecules merge into closed nanocapsules with a graphene surface during the thermal treatment. The conducted studies showed that using HIP treatment of the fullerite C60, it is possible to obtain a chemically resistant material with a high hardness and elasticity, as well as a density lower than that of the graphite. This new material, consisting of closed graphene nanocapsules 2 5 nm in size, formed by sp2 covalent bonds between carbon atoms is promising for various applications, and as a basis for the synthesis of new composite material