Statistical evaluation of a new resistance model for cold-formed stainless steel cross-sections subjected to web crippling

This paper presents a statistical evaluation according to Annex D of EN 1990 (2002) of a new resistance function for web crippling design of cold-formed stainless steel cross-sections. This resistance function was derived by Bock et al. (2013) through the use of carefully validated numerical models with the aim to propose a design expression for stainless steel sections, which are currently designed following the provisions for cold-formed carbon steel sections given in EN 1993-1-3 (2006). Although it was shown that the proposed design equation is appropriate for application to various stainless steels, the statistical uncertainties in material properties that the different types of stainless steels exhibit require an assessment of various partial safety factors. The statistical assessment showed that the proposed resistance function by Bock et al. (2013) requires adjustment to satisfy the safety level set out in EN 1993-1-4 (2006); A recalibration is performed herein. The web crippling design provisions given in EN 1993-1-3 (2006) and SEI/ASCE 8-02 (2002) American standard for application to stainless steel are also statistically evaluated herein. Comparison with test and numerical data showed that the predictions of the recalibrated resistance function are better suited and consistent than existing design provisionsResearch Fund for Coal and Stee

Haemodynamics and flow modification stents for peripheral arterial disease:a review

Endovascular stents are widely used for the treatment of peripheral arterial disease (PAD). However, the development of in-stent restenosis and downstream PAD progression remain a challenge. Stent revascularisation of PAD causes arterial trauma and introduces abnormal haemodynamics, which initiate complicated biological processes detrimental to the arterial wall. The interaction between stent struts and arterial cells in contact, and the blood flow field created in a stented region, are highly affected by stent design. Spiral flow is known as a normal physiologic characteristic of arterial circulation and is believed to prevent the development of flow disturbances. This secondary flow motion is lost in atheromatous disease and its re-introduction after endovascular treatment of PAD has been suggested as a method to induce stabilised and coherent haemodynamics. Stent designs able to generate spiral flow may support endothelial function and therefore increase patency rates. This review is focused on secondary flow phenomena in arteries and the development of flow modification stent technologies for the treatment of PAD

Trichuris muris research revisited: A journey through time

The mouse whipworm Trichuris muris has long been used as a tractable model of human Trichuriasis. Here we look back at the history of T. muris research; from the definition of the species and determination of its life cycle, through to the complex immune responses that we study today. We highlight the key research papers that have developed our understanding of immune responses to this parasite, and reflect on how original concepts have been transformed, as our knowledge of immunology has grown. Although we have a good understanding of host–parasite interactions in the context of the underlying cellular immunology, there are still many aspects of the biology of the Trichuris parasite that remain undefined. We predict that advances in parasite biology will be key in the future development of new and improved treatments for Trichuriasis

Role of the OPG/RANK/RANKL triad in calcifications of the atheromatous plaques: Comparison between carotid and femoral beds

Recent works demonstrated the difference of calcification genesis between carotid and femoral plaques, femoral plaques being more calcified. It has been clearly demonstrated that the molecular triad osteoprotegerin (OPG)/Receptor Activator of NFkB (RANK)/RANK Ligand (RANKL) exerts its activities in the osteoimmunology and vascular system. The aim of this study was to determine their expression and their potential role in calcifications of the atheromatous plaques located in two different peripheral arterial beds, carotid and femoral. The expression of OPG, RANK and RANKL was analyzed by immunochemistry in 40 carotid and femoral samples. Blood OPG and RANKL were quantified using specific ELISA assays. OPG staining was more frequently observed in carotid than in femoral plaques, especially in lipid core. Its expression correlated with macrophage infiltration more abundantly observed in carotid specimens. Surprisingly, serum OPG concentration was significantly lower in carotid population compared to femoral population while RANK and RANKL were equally expressed in both arterial beds. Carotid plaques that are less rich in calcium than femoral specimens, express more frequently OPG, this expression being correlated with the abundance of macrophages in the lesions. These data strengthen the key role played by OPG in the differential calcification in carotid and femoral plaques

Capteur micro-ondes en vue du diagnostic médical de l'athérosclérose

International audienceL'atténuation importante des ondes électromagnétiques (EM) dans les tissus biologiques en raison de leur conductivité est un obstacle important dans l'utilisation des capteurs micro-ondes (MO) destinés aux diagnostics médicaux. Notre objectif étant de développer une technique d'identification des plaques d'athérome carotidiennes en positionnant directement un capteur sur le cou du patient, il est nécessaire que les MO puissent pénétrer suffisamment en profondeur dans les tissus. Des études précédentes ont montré qu'un capteur résonnant à anneaux fendus complémentaires (CSRR) permettait d'identifier des tissus excisés d'animaux ou humain prélevés en postopératoire. Cet article présente une amélioration de ce type de capteurs conçus sur un substrat à faibles pertes permettant d'améliorer le compromis entre l'énergie emmagasinée dans le résonateur, et l'énergie rayonnée dans les tissus biologiques. Les performances du nouveau résonateur ont été validées à partir de simulations EM 3D et de mesures ex-vivo sur des tissus animaux frais (peau, graisse, muscle) de différentes épaisseurs et formes (monocouche et multicouches). Les résultats simulés et expérimentaux ont montré une meilleure résolution et une plus grande profondeur de pénétration dans les tissus par rapport aux précédentes générations de capteurs CSRR