Structural solvability analysis of dynamic process models

The variable structure of dynamic process models is represented by a directed graph termed as the representation graph for the purpose of solvability analysis in this paper. Structural solvability analysis, the determination of the structural differential index and the structural decomposition of the differential–algebraic equations (DAE) model set can be performed using the representation graph. The characteristic features of the representation graph for both index 1 and high index semi-explicit DAE models are presented. Based on the above a novel index reduction procedure for high index models is proposed. The notions and methods are illustrated on simple process examples.     

Crystal Structure of HydG from Carboxydothermus hydrogenoformans: A Trifunctional [FeFe]‐Hydrogenase Maturase

The structure of the radical S‐adenosyl‐L ‐methionine (SAM) [FeFe]‐hydrogenase maturase HydG involved in CN^?/CO synthesis is characterized by two internal tunnels connecting its tyrosine‐binding pocket with the external medium and the C‐terminal Fe₄S₄ cluster‐containing region. A comparison with a tryptophan‐bound NosL structure suggests that substrate binding causes the closing of the first tunnel and, along with mutagenesis studies, that tyrosine binds to HydG with its amino group well positioned for H‐abstraction by SAM. In this orientation the dehydroglycine (DHG) fragment caused by tyrosine Cα?Cβ bond scission can readily migrate through the second tunnel towards the C‐terminal domain where both CN^? and CO are synthesized. Our HydG structure appears to be in a relaxed state with its C‐terminal cluster CysX₂CysX₂₂Cys motif exposed to solvent. A rotation of this domain coupled to Fe₄S₄ cluster assembly would bury its putatively reactive unique Fe ion thereby allowing it to interact with DHG.     

Genome-wide association study between copy number variants and hoof health traits in Holstein dairy cattle

Genome-wide association studies based on SNP have been completed for multiple traits in dairy cattle; however, copy number variants (CNV) could add genomic information that has yet to be harnessed. The objectives of this study were to identify CNV in genotyped Holstein animals and assess their association with hoof health traits using deregressed estimated breeding values as pseudophenotypes. A total of 23,256 CNV comprising 1,645 genomic regions were identified in 5,845 animals. Fourteen genomic regions harboring structural variations, including 9 deletions and 5 duplications, were associated with at least 1 of the studied hoof health traits. This group of traits included digital dermatitis, interdigital dermatitis, heel horn erosion, sole ulcer, white line lesion, sole hemorrhage, and interdigital hyperplasia; no regions were associated with toe ulcer. Twenty candidate genes overlapped with the regions associated with these traits including SCART1, NRXN2, KIF26A, GPHN, and OR7A17. In this study, an effect on infectious hoof lesions could be attributed to the PRAME (Preferentially Expressed Antigen in Melanoma) gene. Almost all genes detected in association with noninfectious hoof lesions could be linked to known metabolic disorders. The knowledge obtained considering information of associated CNV to the traits of interest in this study could improve the accuracy of estimated breeding values. This may further increase the genetic gain for these traits in the Canadian Holstein population, thus reducing the involuntary animal losses due to lameness.     

Global behaviour of a composite stiffened panel in buckling. Part 1: Numerical modelling

The present study analyses an aircraft composite fuselage structure manufactured by the Liquid Resin Infusion (LRI) process and subjected to a compressive load. LRI is based on the moulding of high performance composite parts by infusing liquid resin on dry fibres instead of prepreg fabrics or Resin Transfer Moulding (RTM). Actual industrial projects face composite integrated structure issues as a number of structures (stiffeners, …) are more and more integrated onto the skins of aircraft fuselage. A representative panel of a composite fuselage to be tested in buckling is studied numerically.     

Particle-SfT: A Provably-Convergent,Fast Shape-from-Template Algorithm

The Shape-from-Template (SfT) problem is to recover the 3D shape of a deformable object from a single image, given a 3D template and a deformation constraint. We propose Particle-SfT, a new SfT algorithm which handles isometric and non-isometric deformations. We build Particle-SfT upon a particle system guided by deformation and reprojection constraint projections. Reconstruction is achieved by evolving particles to a globally attractive equilibrium, while taking observable external forces such as gravity into account, if any. Particle-SfT may be used to refine an existing initial shape. However, in practice we simply use the template as initial guess. This is because, as opposed to the existing refining methods, Particle-SfT has an extremely wide convergence basin. Particle-SfT is also faster than the existing refining methods. This is because it moves pieces of the shape’s mesh independently to achieve larger step size by optimal constraint projection. We proved its convergence to a fixed-point. We experimented it with synthetic and real data. It has the same accuracy as the best performing isometric method and consistently outperforms all existing elastic methods in almost all cases, while being much faster.     

The transfer of metallic contamination via contact between solid objects

The transfer of metallic contamination via solid contact is an almost non documented topic in the literature when compared to the spread through liquids which is has been intensively investigated for cleaning studies.This paper presents the transfer mechanisms of metallic aggregates from substrate to substrate though contact with tools used during wafer processing. In addition we propose models which agree with the experimental observations. The influence of several parameters on the transfer coefficients has been investigated, including the type of contamination (deposited films, particles…), the size or shape of the particle, the composition of the particle (metallic or dielectric), the substrate and the roughness and flatness of the plates used to hold the wafers during processing as well as the substrate surface composition (bare Si, oxidized…).The transfer of metals via the contact between solid objects only occurs from particular mechanisms. Not considering electrical forces, the first order parameter on the transfer is the particle size. Global transfer by contact occurs mainly in the 0.5-5 μm range and can be as high as 10%. For the second order, the parameters mentioned previously can affect the transfer of the particles, for example, an increase of the particle roughness induces an increase of the separation distance between particle and substrate which consequently decreases the Van der Waals interactions.     

Further clinical evaluations elicited by functional biological investigations in childhood autism

Data on the protective role of antioxidants in models of atherosclerosis are only partially confirmed in man. Observational and epidemiological data, as well as randomized trials, provide no clear cut indications, because of positive and disappointing results on the use of antioxidants in cardiovascular protection. Despite the lack of a general consensus, recent data reinforce the concept that the regular intake of antioxidants present in food limits the progression of atherosclerosis. When it is possible to monitor the efficacy of any antioxidant therapy with validated markers of oxidation, the potential influence of vitamins and antioxidants on coronary artery disease may eventually be resolved.     

Investigation on the properties of linear PLA-poloxamer and star PLA-poloxamine copolymers for temporary biomedical applications

The objective of this work was to develop and study new biodegradable thermoplastics with improved mechanical properties for potential use as temporary implantable biomaterials. Linear poloxamer and star-shaped poloxamine have been used as macroinitiators for the ring-opening polymerization (ROP) of lactide to yield high molecular weight PLA-based thermoplastic block copolymers. The influence of the nature of the macroinitiator, PLA crystallinity and initial molecular weight on the copolymers properties was investigated by performing a 7-week degradation test in PBS. The evaluation of water uptakes and molecular weights during the degradation pointed out an early hydrolytic degradation of the 100-kg?mol^? 1 copolymers compared to the 200-kg?mol^? 1 ones (molecular weight decrease of ca. 40% and 20%, respectively). A dramatic loss of tensile mechanical properties was also observed for the 100-kg?mol^? 1 copolymers, whereas the 200-kg?mol^? 1 copolymers showed stable or even slightly improved properties with Young's moduli around 500 MPa and yield strains around 3% to 4%. Finally, the cytocompatibility of the more stable 200 kg?mol^? 1 copolymers was confirmed by murine mesenchymal stem cells (MSCs) culture.     

Local Tomography Study of the Fracture of an ERG Metal Foam

As one of the most important analysis techniques for non‐destructive imaging, X‐ray tomography has been widely used in materials science, medical science, and industry to evaluate the behavior of porous materials. By using this method, a three dimensional volume can be inspected in order to visualize in situ the progress of damage in materials and this can be analyzed qualitatively and quantitatively. In the present study, we have used X‐ray tomography to investigate the fracture behavior of an ERG open cell aluminum foam. The process of damage development of a sample undergoing tension and the relation between the inter‐metallics and the cracks can be observed totally by the X‐ray tomography set‐up. Local tomography has in particular been used to image the microstructure at high resolution. A finite element model has also been developed in order to simulate this process of the damage using the 3D data obtained by the tomography.