Juan Manuel García-Ruiz

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We have synthesized inorganic micron-sized filaments, whose microstucture consists of silica-coated nanometer-sized carbonate crystals, arranged with strong orientational order. They exhibit noncrystallographic, curved, helical morphologies, reminiscent of biological forms. The filaments are similar to supposed cyanobacterial microfossils from the(More)
The eggshell of the hen is a highly ordered and mineralised structure, which is sequentially deposited within an acellular milieu – the uterine fluid secreted by the distal oviduct. Spherulitic crystal growth of calcite is initiated on organic aggregates on surface of the eggshell membranes, followed by competition between radial crystallites for space to(More)
The avian eggshell is a composite biomaterial composed of non-calcifying eggshell membranes and the overlying calcified shell matrix. The calcified shell forms in a uterine fluid where the concentration of different protein species varies between the initial, rapid calcification and terminal phases of eggshell deposition. The role of these avian eggshell(More)
The effect of moult on eggshell mechanical properties, on composition and concentrations of organic matrix components and on eggshell microstructure was investigated. The observed changes were studied to understand the role of organic matrix and eggshell microstructure in eggshell strength. Moult was induced by zinc oxide (20 g zinc/kg diet) in 53 ISA Brown(More)
Calcium sulfate minerals such as gypsum play important roles in natural and industrial processes, but their precipitation mechanisms remain largely unexplored. We used time-resolved sample quenching and high-resolution microscopy to demonstrate that gypsum forms via a three-stage process: (i) homogeneous precipitation of nanocrystalline hemihydrate(More)
The precipitation of barium or strontium carbonates in alkaline silica-rich environments leads to crystalline aggregates that have been named silica/carbonate biomorphs because their morphology resembles that of primitive organisms. These aggregates are self-assembled materials of purely inorganic origin, with an amorphous phase of silica intimately(More)
—Several mechanisms have been proposed to explain the interactions between proteins and mineral surfaces, among them a combination of electrostatic, stereochemical interactions and molecular recognition between the protein and the crystal surface. To identify the mechanisms of interaction in the lysozyme– calcium carbonate model system, the effect of this(More)
The Naica Mine in northern Mexico is famous for its giant gypsum crystals, which may reach up to 11 m long and contain fluid inclusions that might have captured microorganisms during their formation. These crystals formed under particularly stable geochemical conditions in cavities filled by low salinity hydrothermal water at 54-58°C. We have explored the(More)
Two complementary approaches are used to enhance the usefulness of X-ray topographies obtained from protein crystals. First, the use of thin plate-like crystals in conjunction with a high intensity, collimated and small source size synchrotron beam produces a large beneficial effect on the level of detail and contrast of topographies for the quantification(More)