Trace-elemental and multi-isotopic (Sr-Nd-Pb) discrimination of jade in the circum-Caribbean: Implications for pre-colonial inter-island exchange networks

Dense and strong, hydrothermal-metasomatic jadeitite and jadeite-omphacite rocks were used as tools and adornments throughout the wider Caribbean since initial inhabitation. Regionally, rich sources of jadeitite and jadeite-omphacite jade are known only in Guatemala (north and south of the Motagua Fault Zone), eastern Cuba and the northern Dominican Republic, establishing that humans transported jadeitic material over vast distances. This study validates that geochemical fingerprinting is a viable provenance method for Caribbean pre-colonial jadeitic lithologies. An assemblage of 101 source rocks has been characterised for trace element and combined Sr-Nd-Pb isotope compositions. Four statistical approaches (Principal Component Analysis, t-Distributed Stochastic Neighbour Embedding, Decision Tree, and Multiclass Regression) were assessed, employing source-distinct trace element ratios. A multiclass regression technique based on trace element ratios of immobile high field strength, light to medium rare earth and fluid-mobile, large-ion-lithophile elements is shown to be most effective in discriminating the four source regions. Ninety-one % of the Guatemalan samples can be discriminated from the Dominican and Cuban sources using La/Th, Zr/Hf and Y/Th ratios. Jadeitic rocks cropping out in the Dominican Republic can be distinguished from Cuban jades employing Er/Yb, Nb/Ta and Ba/Rb ratios with 71% certainty. Furthermore, the two Guatemala sources, north and south of the Motagua Fault Zone, can be discriminated by using (among others) Zr/Hf, Ta/Th, La/Sm and Dy/Y ratios with an 89% success rate. This raises the possibility of determining, in detail, former trading and mobility networks between different islands and the Meso- and Central American mainland within the Greater Caribbean. The provenance technique was applied to 19 pre-colonial jade celts excavated from the Late Ceramic Age Playa Grande archaeological site in the northern Dominican Republic. Three artefacts are discriminated as derived from the Guatemalan source, indicating that, despite a source of jade within 25 km, material was traded from Guatemala. The presence of Guatemalan jade in the Playa Grande lithic assemblage provides further evidence of large scale (>3000 km), regional trading and indigenous knowledge transfer networks.This research received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007–2013)/ERC grant agreement No 319209 (ERC-Synergy NEXUS 1492) and the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654208 (Europlanet 2020 RI). We are grateful to the Museo del Hombre Dominicano for providing the Playa Grande samples. Thanks to Richard Smeets, Bas van der Wagt, Kirsten van Zuilen, Bouke Lacet, Eva Kelderman and Quinty Boosten for analytical assistance

Structural investigation of donor age effect on human bone marrow mesenchymal stem cells: FTIR spectroscopy and imaging

Stem cell studies hold enormous potential for development of new therapies for tissue regeneration and repair. Bone marrow mesenchymal stem cells (BM-MSCs) can differentiate into a variety of non-hematopoietic tissues and contribute maintenance of healthy hematopoiesis by providing supportive cellular microenvironment into BM. Here, we investigated age-related differences in BM-MSCs by using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and FTIR imaging together with hierarchical clustering as a novel methods to clarify global alterations in the structure and function of macromolecules in characterized BM-MSCs of different aged donors. The results may contribute to identification of age-related new molecular marker(s) to determine the effects of donor age on MSCs. The spectral results reflected that there were significant increases in the concentration of saturated lipids, proteins, glycogen, and nucleic acids in children and adolescent group BM-MSCs when compared to the infants and early and mid adults. The concentration of mentioned macromolecules in adult (early and mid) BM-MSCs were significantly lower than the concentrations in the children and adolescents. These results were attributed to the increase in the proliferation activity in younger BM-MSCs. The distribution of macromolecules into the cells was shown as in the form of chemical maps by FTIR imaging, and the results are in agreement with the ATR-FTIR spectroscopy results. The cellular activity degree was determined by the thiazolyl blue tetrazolium bromide (MTT) proliferation assay to support ATR-FTIR spectroscopy results. BM-MSCs of five different age groups were discriminated by making the hierarchical cluster analysis where the spectral data according to alterations in structure and composition of macromolecules were considered