Experimental determination of the multi-axial strain transfer from CFRP-laminates to embedded Bragg sensor

When embedded, optical fibre Bragg gratings are considered to be very valuable in terms of strain measurements of large composite structures for a number of reasons (safety rules, design criteria…). However, the strain field measured by the embedded optical fibre Bragg grating is not necessarily the one present in the composite material. Especially the measurement of transverse strain components is not that straight forward! In a previous paper, the multi-axial strain transfer from host material to sensor was determined by using a finite element method. In this paper, a method is defined to experimentally determine the multi-axial strain transfer. As an example, the strain transfer of a cross-ply laminate to a non-coated 80μm diameter Bragg sensor was determined. The different experiments (tensile tests and transverse compression tests) needed to obtain this transfer matrix are discussed. Good similarity was found between the numerically and experimentally determined transfer matrices

SMARTFIBER: enabling cost-effective, miniaturized structural health-monitoring of composite structures

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Crystal Structure of Human TWEAK in Complex with the Fab Fragment of a Neutralizing Antibody Reveals Insights into Receptor Binding.

The tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a multifunctional cytokine playing a key role in tissue regeneration and remodeling. Dysregulation of TWEAK signaling is involved in various pathological processes like autoimmune diseases and cancer. The unique interaction with its cognate receptor Fn14 makes both ligand and receptor promising targets for novel therapeutics. To gain insights into this important signaling pathway, we determined the structure of soluble human TWEAK in complex with the Fab fragment of an antibody selected for inhibition of receptor binding. In the crystallized complex TWEAK is bound by three Fab fragments of the neutralizing antibody. Homology modeling shows that Fab binding overlaps with the putative Fn14 binding site of TWEAK. Docking of the Fn14 cysteine rich domain (CRD) to that site generates a highly complementary interface with perfectly opposing charged and hydrophobic residues. Taken together the presented structure provides new insights into the biology of TWEAK and the TWEAK/Fn14 pathway, which will help to optimize the therapeutic strategy for treatment of related cancer types and autoimmune diseases

On the orthotropic elasto-plastic material response of additively manufactured polyamide 12

The mechanical response of polymers such as polyamide 12 (PA-12) manufactured through additive manufac-turing, is significantly affected by the layered manufacturing approach and the printer settings used during the creation of the parts. As a result, the mechanical performance can differ significantly from PA-12 parts creat-ed through conventional techniques such as injection molding, and a detailed study of the material mechanical behavior is necessary. This work presents an in-depth study of the response of PA-12 to tensile loading and the challenges involved in obtaining qualitative and repeatable results. The full elasto-plastic curves are meas-ured during tensile testing and the effect of printing direction is taken into account in order to investigate whether orthotropic material behavior can be observed. All parts were manufactured using commercially avail-able selective laser sintering (SLS) printers. Digital image correlation was used extensively to obtain high-accuracy strain measurement over the entire elasto-plastic range up to failure. The results show an isotropic elastic response of PA-12, with orthotropic failure properties and the presence of significant viscous contribu-tions in the material response

A finite element model capable of predicting resin pockets for arbitrary inclusions in composite laminates

This work presents the progress in the development of a finite element model capable of predicting resin pockets occurring in composite structures with embedded sensors. The F.E.- model is built using standard tools in ABAQUS software, avoiding the need of specialized coding. Both progresses in material characterization as well as finite element modeling are shown. The model will eventually be used to optimize the shape of an embedded optical fibre interrogator used within the FP7 ‘SmartFiber’ projec

The calcium-sensing receptor as a regulator of cellular fate in normal and pathological conditions

The calcium-sensing receptor (CaSR) belongs to the evolutionarily conserved family of plasma membrane G protein-coupled receptors (GPCRs). Early studies identified an essential role for the CaSR in systemic calcium homeostasis through its ability to sense small changes in circulating calcium concentration and to couple this information to intracellular signaling pathways that influence parathyroid hormone secretion. However, the presence of CaSR protein in tissues is not directly involved in regulating mineral ion homeostasis points to a role for the CaSR in other cellular functions including the control of cellular proliferation, differentiation and apoptosis. This position at the crossroads of cellular fate designates the CaSR as an interesting study subject is likely to be involved in a variety of previously unconsidered human pathologies, including cancer, atherosclerosis and Alzheimer's disease. Here, we will review the recent discoveries regarding the relevance of CaSR signaling in development and disease. Furthermore, we will discuss the rational for developing and using CaSR-based therapeutics