Search

Abstract: The chaperone-like activity and the oligomeric state of αB-crystallin were studied at different temperatures and in the presence of urea and thiocyanate. The activity, assessed measuring the ability of αB-crystallin to prevent the aggregation of denatured insulin, strongly depends on temperature. While a significant activity increase was detected at 42 °C, the presence of urea and thiocyanate does not affect the protein activity in an irreversible way. In-solution SAXS measurements performed in the same experimental conditions showed that αB-crystallin forms near-spherical, hollowed, polydisperse oligomers, whose dimensions change above 42 °C. Moreover, in the presence of urea and thiocyanate, a global fit analysis confirms the high stability of αB-crystallin assemblies in relationship with their variable quaternary structure. In particular, the changes in the inner radius as well as the thickness and dispersion of the protein shell, account for the preservation of the chaperone-like activity. [Copyright &y& Elsevier]

Abstract: The present contribution is concerned with a combined experimental and numerical design of graded cellular materials for multifunctional aerospace application performed in the context of an integrated research project funded by the European Commission. The primary objective is an exploration of the potential of functionally graded materials as sandwich cores for multifunctional application. With particulate advanced pore morphology (APM) foams and hollow spheres assemblies, two different types of particle-based cellular base materials are considered. Based on these constituent materials, functionally graded sandwich cores are designed in a combined numerical and experimental approach. Their properties and their performance in the desired application are investigated and optimized. The performance of the optimized material is compared to the performance of a non-graded sandwich core in the numerical simulation of a bird strike experiment. [Copyright &y& Elsevier]

Abstract: Synchrotron radiation micro-computed tomography (SRμCT) revealed the microstructure of a CEL2 glass–ceramic scaffold with macropores of several hundred microns characteristic length, in terms of the voxel-by-voxel 3D distribution of the attenuation coefficients throughout the scanned space. The probability density function of all attenuation coefficients related to the macroporous space inside the scaffold gives access to the tomograph-specific machine error included in the SRμCT measurements (also referred to as instrumental resolution function). After Lorentz function-based clearing of the measured CT data from the systematic resolution error, the voxel-specific attenuation information of the voxels representing the solid skeleton is translated into the composition of the material inside one voxel, in terms of the nanoporosity embedded in a dense CEL2 glass–ceramic matrix. Based on voxel-invariant elastic properties of dense CEL2 glass–ceramic, continuum micromechanics allows for translation of the voxel-specific nanoporosity into voxel-specific elastic properties. They serve as input for Finite Element analyses of the scaffold structure. Young''s modulus of a specific CT-scanned macroporous scaffold sample, predicted from a Finite Element simulation of a uniaxial compression test, agrees well with the experimental value obtained from an ultrasonic test on the same sample. This highlights the satisfactory predictive capabilities of the presented approach. [Copyright &y& Elsevier]