Elemental distribution, solute solubility and defect free volume in nanocrystalline restricted-equilibrium Cu-Ag alloys.

In this article we study the elemental distribution and solute solubility in nanocrystalline alloys of immiscible components near restricted equilibrium for the case of the binary Cu-Ag system. As predicted from thermodynamic considerations, a grain boundary segregated monophase alloy is observed in the annealed mechanically alloyed state for low Ag content by using atom probe tomography. From the detected Ag solute grain boundary enrichment the segregation free enthalpy is estimated to range between -25 and -49 kJ mol(-1) following the McLean equation, in agreement with values reported for coarse-grained Cu-Ag.

Properties of injectable ready-to-use calcium phosphate cement based on water-immiscible liquid.

Calcium phosphate cements (CPCs) are highly valuable materials for filling bone defects and bone augmentation by minimal invasive application via percutaneous injection. In the present study some key features were significantly improved by developing a novel injectable ready-to-use calcium phosphate cement based on water-immiscible carrier liquids. A combination of two surfactants was identified to facilitate the targeted discontinuous exchange of the liquid for water after contact with aqueous solutions, enabling the setting reaction to take place at distinct ratios of cement components to water.

Weak glycolipid binding of a microdomain-tracer peptide correlates with aggregation and slow diffusion on cell membranes.

Organized assembly or aggregation of sphingolipid-binding ligands, such as certain toxins and pathogens, has been suggested to increase binding affinity of the ligand to the cell membrane and cause membrane reorganization or distortion. Here we show that the diffusion behavior of the fluorescently tagged sphingolipid-interacting peptide probe SBD (Sphingolipid Binding Domain) is altered by modifications in the construction of the peptide sequence that both result in a reduction in binding to ganglioside-containing supported lipid membranes, and at the same time increase aggregation on the cell plasma membrane, but that do not change relative amounts of secondary structural features. We tested the effects of modifying the overall charge and construction of the SBD probe on its binding and diffusion behavior, by Surface Plasmon Resonance (SPR; Biacore) analysis on lipid surfaces, and by Fluorescence Correlation Spectroscopy (FCS) on live cells, respectively.

Chitin-based scaffolds are an integral part of the skeleton of the marine demosponge Ianthella basta.

The skeletons of demosponges, such as Ianthella basta, are known to be a composite material containing organic constituents. Here, we show that a filigree chitin-based scaffold is an integral component of the I. basta skeleton.

Effect of chondroitin sulphate on material properties and bone remodelling around hydroxyapatite/collagen composites.

Chondroitin sulphate (CS) has an anti-inflammatory effect and increases the regeneration ability of injured bone. The goal of this study was to characterize the material properties and osteoconductive potency of calcium phosphate bone cements modified with CS. The early interface reaction of cancellous bone to a nanokristalline hydroxyapatite cement containing type I collagen (HA/Coll) without and with CS (HA/Coll/CS) in a rat tibia model was evaluated.

Phosphoserine--a convenient compound for modification of calcium phosphate bone cement collagen composites.

Temporary bone replacement materials on the basis of calcium phosphates and hydroxyapatite (HAP) are used in surgery for filling bone defects. Components which are able to control the nucleation and crystal growth of HAP through their functional groups and which can additionally activate bone cells may be helpful in the development of materials with enhanced remodelling in vivo. In this study, the influence of O-phospho-L-serine (PS) on the materials properties of calcium phosphate bone cement composites was investigated.