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Abstract: Context. Laboratory analogues can provide physical constraints to the interpretation of astronomical observations of cosmic dust but clearly do not experience the same formation conditions. To distinguish between properties intrinsic to the material and properties imprinted by their means of formation requires extensive characterisation. Aims. Sol-gel methods can produce amorphous silicates with potentially high reproducibility, but often require long drying times (24+ hours) at elevated temperatures in air, controlled atmosphere, or vacuum. We investigate the possibility that microwave drying can be used to form amorphous silicate on a timescale of ∼10 minutes and characterise their structural and spectroscopic properties relative to silicates produced by other drying methods. Methods. Microwave-dried amorphous MgSiO3, Fe 0.1Mg0.9SiO3 and Mg2SiO4 are characterised using X-ray powder diffraction, total X-ray scattering, small angle X-ray scattering and mid-IR FTIR spectroscopy, and compared to samples produced from the same gels, but dried in-air and under vacuum. The development of crystalline structure in the microwave-dried silicates via thermal annealing up to 999 ◦C is also investigated using in situ X-ray powder diffraction. Results. At the inter-atomic level the silicate structures are largely independent of drying method, however largerscale structured domains, ranging from a ∼few×10 ˚A to∼100’s ˚A in size, are observed. These are ordered as mass fractals with discernible variation caused by the drying processes. The mid-IR 10 μm band profile is also found to be influenced by the drying process, likely due to the way removal of water and bonded OH influences the distribution of tetrahedral species. However, microwave drying also allows Fe to be easily incorporated into the silicate structure. In situ annealing shows that for amorphous MgSiO3 crystalline forsterite, enstatite and cristobalite are high temperature phases, while for Mg2SiO4 forsterite crystallises at lower temperatures followed by cristobalite at high temperature. For Fe0.1Mg0.9SiO3 the crystallisation temperature is significantly increased and only forsterite is observed. Crystalline SiO2 may be diagnostic of Mg-rich, Fe-poor grain mineralogies. The results are discussed in relation to the different thermal conditions required for dust to crystallise within protoplanetary disk lifetimes. Conclusions. Sol-gel microwave drying provides a fast and easy method of producing amorphous Mg- and Fe,Mg-silicates of both pyroxene and olivine compositions. Their structure and spectroscopic characteristics although similar to silicates produced using other drying methods, exhibit subtle variations which are particularly manifest spectroscopically in the mid-IR, and structurally over medium- and long-range length scales.

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Abstract: The major challenge of Research in bone surgery is to develop strategies to repair large bone defects. Bone grafting technique is the gold standard to fill and heal these kind of defects. This work address the evolution of the mechanical properties as regard to bone regeneration microstructure. Managing such a time dependent (different regeneration step) and spatially resolved (strain field across natural/reconstructed bone interface) process is achieved through a quantitative analysis of the mechanical strain distribution supported by the mineral part of bone architecture (hydroxyapatite – Hap) and crystal microstructural features (size distribution, spatial pattern). SAXS/WAXS (Small- and Wide- Angle X-ray Scattering) experiments will highlight strain distribution respectively in the reconstructed bone’s collagen fibrils and minerals, through mechanical state mapping over a surgically created defect under in situ tensile testing on samples harvested at different regeneration stages.

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Abstract: Hypothesis: At low temperatures stability issues arise in commercial detergent products when surfactant crystallisation occurs, a process which is not currently well-understood. An understanding of the phase transition can be obtained using a simple binary SDS (sodium dodecyl sulfate) + DDAO (N,N-dimethyldodecylamine N-oxide) aqueous system. It expected that the crystallisation temperature of an SDS system can be lowered with addition of DDAO, thus providing a route to improve detergent stability. Experiments: Detergent systems are typically comprised of anionic surfactants, non-ionic surfactants and water. This study explores the crystallisation of a three component system consisting of sodium dodecyl sulfate (SDS), N,N–dimethyldodecylamine N-oxide (DDAO), and water using wide-angle X-ray scattering (WAXS), differential scanning calorimetry (DSC) and confocal Raman microscopy. Findings: The presence of DDAO lowered the crystallisation temperature of a 20 wt. % SDS system. For all aqueous mixtures of SDS + DDAO at low temperatures, SDS hydrated crystals, SDS.1/2H2O or SDS.H2O, formed. SDS hydrates comprising of layers of SDS separated by water layers. DDAO tended to reside in the vicinity of these SDS crystals. In the absence of DDAO an additional intermediary hydrate structure, SDS.1/8H2O, formed whereas for mixed SDS + DDAO systems no such structure was detected during crystallisation.

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Abstract: Solid supported lipid multilayers have been widely studied as model cell membranes and as a platform for novel materials. Conventionally, they are prepared from drop casting or spin coating of lipids dissolved in organic solvents, and lipid multilayers prepared from aqueous media have not been previously reported, due to extremely low lipid solubility (i.e. cmc ~10-9 M) in water. Here, the preparation of dioleoylphosphatidylcholine (DOPC) multilayers by drop casting aqueous small unilamellar and multilamellar vesicle or liposome (i.e. SUV and MLV) dispersions is reported on different surfaces, including mica, positively charged polyethylenimine (PEI) coated mica, and stearic trimethylammonium iodide (STAI) coated mica which exposes a monolayer of hydrocarbon tails. X-ray reflectivity (XRR) measurements using a unique “bending mica” method confirm the DOPC multilayer structure on all these substrates, and the influence of the substrate surface chemistry on the multilayer structure is discussed. We suggest that DOPC liposomes serve both as a delivery matrix where appreciable lipid concentration in water (~25 mg mL-1 or 14 mM, i.e. >107 cmc) is feasible, and as a structural precursor where the lamellar structure is readily retained on rupture of the vesicles at the solid surface upon solvent evaporation to facilitate rapid multilayer formation. Our results point towards a controlled preparation of ordered lipid multilayers by tailoring the liposome homogeneity and substrate surface properties, potentially offering a simple method for the inclusion of hydrophilic functional additives (e.g. drugs or nanoparticles) into lipid multilayer based hybrid materials.