A New Model for Void Coalescence by Internal Necking

A micromechanical model for predicting the strain increment required to bring a damaged material element from the onset of void coalescence up to final fracture is developed based on simple kinematics arguments. This strain increment controls the unloading slope and the energy dissipated during the final step of material failure. Proper prediction of the final drop of the load carrying capacity is an important ingredient of any ductile fracture model, especially at high stress triaxiality. The model has been motivated and verified by comparison to a large set of finite element void cell calculations.

Predicting Important Residues and Interaction Pathways in Proteins Using Gaussian Network Model: Binding and Stability of HLA Proteins

A statistical thermodynamics approach is proposed to determine structurally and functionally important residues in native proteins that are involved in energy exchange with a ligand and other residues along an interaction pathway. The structure-function relationships, ligand binding and allosteric activities of ten structures of HLA Class I proteins of the immune system are studied by the Gaussian Network Model. Five of these models are associated with inflammatory rheumatic disease and the remaining five are properly functioning. In the Gaussian Network Model, the protein structures are modeled as an elastic network where the inter-residue interactions are harmonic. Important residues and the interaction pathways in the proteins are identified by focusing on the largest eigenvalue of the residue interaction matrix. Predicted important residues match those known from previous experimental and clinical work. Graph perturbation is used to determine the response of the important residues along the interaction pathway. Differences in response patterns of the two sets of proteins are identified and their relations to disease are discussed

Recent advances in ankylosing spondylitis: understanding the disease and management

The term spondyloarthritis refers to a group of immune-mediated diseases characterised by inflammation of the axial skeleton, peripheral joints, and entheses. Ankylosing spondylitis (AS) is the most common and characteristic of these entities and even though it was first described over two centuries ago, the understanding of the underlying disease mechanism remains incomplete. It is known that around 40% of patients with AS have subclinical bowel inflammation, suggesting that the origin of the disease could be in the gut. Also, more genes and new molecules have demonstrated a role in the pathogenesis of AS. In this review, we analyse the latest therapies for spondyloarthritis and the most relevant discoveries over the last three years, together with their implications for different aspects of the disease

Diazotization of S-sulfonyl-cysteines

We report the preparation of enantiomerically enriched β-thio-α-hydroxy and α-chloro carboxylic acid and ester building blocks by diazotization of S-sulfonyl-cysteines. The thiosulfonate protecting group demonstrated resistance to oxidation and attenuation of sulfur's nucleophilicity by the anomeric effect. The key transformation was optimized by a 22 factorial design of experiment, highlighting the unique reactivity of cysteine derivatives in comparison with aliphatic amino acids.National Science Foundation Graduate Research Fellowship Program (grant no. 1122374

PROCESSING AND CHARACTERIZATION OF THIN FILM Cux(Ge28Se60Sb12)1-x ION-SELECTIVE ELECTRODE MEMBRANE

International audienceThis work relates to the elaboration and characterization of Ion-Selective Electrodes (ISEs) based upon chalcogenide membrane sensitive to Cu2+ ion in aqueous solution for continuous and in situ measurements. The membrane material is a thin film deposited by RF co-sputtering of Ge28Se60Sb12chalcogenide glass and metal copper. The composition of the film highly doped with copper was analysed using Energy Dispersive Spectroscopy (EDS) and Secondary Ion Mass Spectrometry (SIMS). The membrane / solution interface interactions were characterised using X-ray Photoelectronic Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS). These miniaturised ISEs exhibit Nernstian responses (30 mV / pCu) in a large copper (II) concentration range and a detection limit close to 1×10-6 M

PROCESSING AND CHARACTERIZATION OF THIN FILM Cux(Ge28Se60Sb12)1-x ION-SELECTIVE ELECTRODE MEMBRANE

International audienceThis work relates to the elaboration and characterization of Ion-Selective Electrodes (ISEs) based upon chalcogenide membrane sensitive to Cu2+ ion in aqueous solution for continuous and in situ measurements. The membrane material is a thin film deposited by RF co-sputtering of Ge28Se60Sb12chalcogenide glass and metal copper. The composition of the film highly doped with copper was analysed using Energy Dispersive Spectroscopy (EDS) and Secondary Ion Mass Spectrometry (SIMS). The membrane / solution interface interactions were characterised using X-ray Photoelectronic Spectroscopy (XPS) and Electrochemical Impedance Spectroscopy (EIS). These miniaturised ISEs exhibit Nernstian responses (30 mV / pCu) in a large copper (II) concentration range and a detection limit close to 1×10-6 M