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We report here a molecular survey based on 16S rRNA genes of the bacterial diversity found in two deep-sea vent niches at the Mid-Atlantic Ridge: hydrothermal sediment (Rainbow site), and microcolonizers made of three different substrates (organic-rich, iron-rich and pumice) that were exposed for 15 days to a vent emission. Bacterial diversity in sediment(More)
Lead soaps can be found in archaeological cosmetics as well as in oil paintings, as product of interactions of lead salts with oil. In this context, a better understanding of the formation of lead soaps allows a follow-up of the historical evolution of preparation recipes and provides new insights into conservation conditions. First, ancient recipes of both(More)
A microstructural, mineralogical, and chemical study of the nacre-prisms boundary in the shells of Pinctada margaritifera shows that this boundary is not an abrupt transition, but that there exists a distinct fibrous layer with clear topographic structures and evidence of growth lines. A three-step biomineralization process is proposed that involves changes(More)
The microstructure and composition of two mollusc shells were investigated using a combination of light microscopy, SEM, EPMA, and XANES. The shells of Pinna and Pinctada are composed of calcite prisms separated by organic walls. The prismatic units of Pinna are monocrystalline, and those of Pinctada are polycrystalline with internal organic radial(More)
New information about calcium status in human scalp hair shaft, deduced from X-ray micro-fluorescence imaging, including its distribution over the hair section, the existence of one or several binding-types and its variation between people, is presented. The existence of two different calcium types is inferred. The first one corresponds to atoms (or ions)(More)
Red Pompeian paintings, very famous for their deep intensity, are currently suffering from darkening. The origins of this darkening degradation are not clearly identified yet and remain a major issue for curators. In the specific case of cinnabar (HgS)-based red pigment, a photoinduced conversion into black metacinnabar is usually suspected. This work is(More)
The microchemical environment of neuromelanin (NM) in whole neurons from formalin fixed and paraffin embedded human substantia nigra sections were characterized using synchrotron chemical X-ray microscopy. Concentrations of NM-associated elements increased in the developing brain; the highest levels of most elements were found in the mature brain but the(More)
Complex biomolecules absorb in the mid-infrared (lambda = 2-20 microm), giving vibrational spectra associated with structure and function. We used Fourier transform infrared (FTIR) microspectroscopy to "fingerprint" locations along the length of human small and large intestinal crypts. Paraffin-embedded slices of normal human gut were sectioned (10 microm(More)
Markers of gastrointestinal (GI) stem cells remain elusive. We employed synchrotron Fourier-transform infrared (FTIR) microspectroscopy to derive mid-infrared (IR) spectra along the length of human GI crypts. Tissue sections (10-μm thick) were floated onto BaF2 windows and image maps were acquired of small intestine and large bowel crypts in transmission(More)
Some ascidians (sea squirts) accumulate the transitional metal vanadium in their blood cells at concentrations of up to 350 mM, about 10(7) times its concentration found in seawater. There are approximately 10 different types of blood cell in ascidians. The identity of the true vanadium-containing blood cell (vanadocyte) is controversial and little is known(More)