Spark plasma sintering of damage tolerant and machinable YAM ceramics

Single-phase Y_(4)Al_(2)O_(9)(YAM)powders were synthesized via solid-state reaction starting from nano-sized Al_(2)O_(3) and Y_(2)O_(3).Fully dense(99.5%)bulk YAM ceramics were consolidated by spark plasma sintering(SPS)at 1800℃.We demonstrated the excellent damage tolerance and good machinability of YAM ceramics.Such properties are attributed to the easy slipping along the weakly bonded crystallographic planes,resulting in multiple energy dissipation mechanisms such as transgranular fracture,shear slipping and localized grain crushing.

Carboxylated-xyloglucan and peptide amphiphile co-assembly in wound healing

Hydrogel wound dressings can play critical roles in wound healing protecting the wound from trauma or contamination and providing an ideal environment to support the growth of endogenous cells and promote wound closure.This work presents a self-assembling hydrogel dressing that can assist the wound repair process mimicking the hierarchical structure of skin extracellular matrix.To this aim,the co-assembly behaviour of a carboxylated variant of xyloglucan(CXG)with a peptide amphiphile(PA-H3)has been investigated to generate hierarchical constructs with tuneable molecular composition,structure,and properties.Transmission electron microscopy and circular dichroism at a low concentration shows that CXG and PA-H3 co-assemble into nanofibres by hydrophobic and electrostatic interactions and further aggregate into nanofibre bundles and networks.At a higher concentration,CXG and PA-H3 yield hydrogels that have been characterized for their morphology by scanning electron microscopy and for the mechanical properties by smallamplitude oscillatory shear rheological measurements and compression tests at different CXG/PAH3 ratios.A preliminary biological evaluation has been carried out both in vitro with HaCat cells and in vivo in a mouse model.