Glass transition temperatures and crystallization kinetics of a synthetic, anhydrous, amorphous calcium-magnesium carbonate.

We report the first calorimetric observations of glass transition temperatures and crystallization rates of anhydrous, amorphous calcium-magnesium carbonate using fast scanning differential scanning calorimetry. Hydrous amorphous CaMgCO · 0.5HO (ACMC) solid was precipitated from a MgCl-NaHCO buffered solution, separated from the supernatant, and freeze-dried.

Formation of Amorphous Iron-Calcium Phosphate with High Stability.

Amorphous iron-calcium phosphate (Fe-ACP) plays a vital role in the mechanical properties of teeth of some rodents, which are very hard, but its formation process and synthetic route remain unknown. Here, the synthesis and characterization of an iron-bearing amorphous calcium phosphate in the presence of ammonium iron citrate (AIC) are reported. The iron is distributed homogeneously on the nanometer scale in the resulting particles.

Multiscale Reciprocal Space Mapping of Magnetite Mesocrystals.

Mesocrystals are a class of nanostructured material, where a multiple-length-scale structure is a prerequisite of many interesting phenomena. Resolving the mesocrystal structure is quite challenging due to their structuration on different length scales. The combination of small- and wide-angle X-ray scattering (SAXS and WAXS) techniques offers the possibility of non-destructively probing mesocrystalline structures simultaneously, over multiple length scales to reveal their microscopic structure.

Nested Formation of Calcium Carbonate Polymorphs in a Bacterial Surface Membrane with a Graded Nanoconfinement: An Evolutionary Strategy to Ensure Bacterial Survival.

It is the intention of this study to elucidate the nested formation of calcium carbonate polymorphs or polyamorphs in the different nanosized compartments. With these observations, it can be concluded how the bacteria can survive in a harsh environment with high calcium carbonate supersaturation. The mechanisms of calcium carbonate precipitation at the surface membrane and at the underlying cell wall membrane of the thermophilic soil bacterium DSM 13240 have been revealed by high-resolution transmission electron microscopy and atomic force microscopy.

Cross-Linking of Apatite-Gelatin Nanocomposites as the Basis for Dentine Replacement Materials.

A novel approach for the production of a bioinspired dentine replacement material is introduced. An apatite-gelatin nanocomposite material was cross-linked with various cross-linkers. These nanocomposites have a high resemblance to mammalian dentine regarding its composition and properties.

Correction: Exploring the 3D structure and defects of a self-assembled gold mesocrystal by coherent X-ray diffraction imaging.

Correction for 'Exploring the 3D structure and defects of a self-assembled gold mesocrystal by coherent X-ray diffraction imaging' by Jerome Carnis et al., Nanoscale, 2021, DOI: 10.1039/D1NR01806J.

Exploring the 3D structure and defects of a self-assembled gold mesocrystal by coherent X-ray diffraction imaging.

Mesocrystals are nanostructured materials consisting of individual nanocrystals having a preferred crystallographic orientation. On mesoscopic length scales, the properties of mesocrystals are strongly affected by structural heterogeneity. Here, we report the detailed structural characterization of a faceted mesocrystal grain self-assembled from 60 nm sized gold nanocubes.

Podosome-Driven Defect Development in Lamellar Bone under the Conditions of Senile Osteoporosis Observed at the Nanometer Scale.

The degradation mechanism of human trabecular bone harvested from the central part of the femoral head of a patient with a fragility fracture of the femoral neck under conditions of senile osteoporosis was investigated by high-resolution electron microscopy. As evidenced by light microscopy, there is a disturbance of bone metabolism leading to severe and irreparable damages to the bone structure. These defects are evoked by osteoclasts and thus podosome activity.

Nonclassical Recrystallization.

Applications in the fields of materials science and nanotechnology increasingly demand monodisperse nanoparticles in size and shape. Up to now, no general purification procedure exists to thoroughly narrow the size and shape distributions of nanoparticles. Here, we show by analytical ultracentrifugation (AUC) as an absolute and quantitative high-resolution method that multiple recrystallizations of nanocrystals to mesocrystals is a very efficient tool to generate nanocrystals with an excellent and so-far unsurpassed size-distribution (PDI =1.

Crystals of Benzamide, the First Polymorphous Molecular Compound, Are Helicoidal.

The growth of spontaneously twisted crystals is a common but poorly understood phenomenon. An analysis of the formation of twisted crystals of a metastable benzamide polymorph (form II) crystallizing from highly supersaturated aqueous and ethanol solutions is given here. Benzamide, the first polymorphic molecular crystal reported (1832), would have been the first helicoidal crystal observed had the original authors undertaken an analysis by light microscopy.

Inorganic Porous Bulk Discs as a Matrix for Thin-Layer Chromatography and Translucent Hard Composite Materials.

Magnesium-stabilized amorphous calcium carbonate (Mg-ACC), amorphous magnesium calcium silicate hydrate (MCSH), and hydroxyapatite (HAp) are prepared by a precipitation method. By cold-pressing these particles, it is possible to produce porous bulk discs with a narrow pore size distribution. These porous inorganic discs (Mg-ACC, MCSH, and HAp) are investigated as stationary phases to study the chromatographic behavior and adsorption ability of rhodamine B, methylene blue, and ribonuclease.