Application of recent advances in hydrodynamic methods for characterising mucins in solution

Mucins are the primary macromolecular component of mucus—nature’s natural lubricant—although they are poorly characterised heterogeneous substances. Recent advances in hydrodynamic methodology now offer the opportunity for gaining a better understanding of their solution properties. In this study a combination of such methods was used to provide increased understanding of a preparation of porcine intestinal mucin (PIM), MUC2 mucin, in terms of both heterogeneity and quantification of conformational flexibility. The new sedimentation equilibrium algorithm SEDFIT-MSTAR is applied to yield a weight average (over the whole distribution) molar mass of 7.1 × 106 g mol−1, in complete agreement with size exclusion chromatography coupled with multi-angle light scattering (SEC-MALS), which yielded a value of 7.2 × 106 g mol−1. Sedimentation velocity profiles show mucin to be very polydisperse, with a broad molar mass distribution obtained using the Extended Fujita algorithm, consistent with the elution profiles from SEC-MALS. On-line differential pressure viscometry coupled to the SEC-MALS was used to obtain the intrinsic viscosity [η] as a function of molar mass. These data combined with sedimentation coefficient data into the global conformation algorithm HYDFIT show that PIM has a flexible linear structure, with persistence length Lp ~10 nm and mass per unit length, ML ~2380 g mol−1 nm−1, consistent with a Wales-van Holde ratio of ~1.2 obtained from the concentration dependence of the sedimentation coefficient

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Le premier réacteur nucléaire à eau légère dédié à la production d’électricité a été mis en service à Shippingport aux Etats-Unis en 1957, et a alimenté la ville de Pittsburgh. Le 50ème anniversaire de cet événement est l’occasion de rendre hommage aux hommes et aux femmes qui ont fait de ce type de réacteur l’une des sources majeures d’énergie pour l’humanité, et l’une des solutions les plus efficaces pour combattre le changement climatique en ce début de 21ème siècle. Le présent article participe à cet hommage dans le domaine de la Recherche et Développement (R&D). On y décrit le rôle de la R&D dans l’essor des réacteurs à eau légère au travers de quelques exemples qui jalonnent les 50 dernières années. Ils ont trait aux apports de la science des matériaux dans la fabrication et l’exploitation du composant le plus important en termes de sûreté dans ces réacteurs : la cuve. Chacun d’eux illustre la volonté et l’engagement d’équipes qui ont cherché à ouvrir des voies de progrès dans des domaines aussi divers que la sidérurgie, la chaudronnerie, la mécanique des matériaux, la compréhension des effets d’irradiation, etc. Pas à pas, ces exemples exposent une partie des connaissances et des outils qui contribuent à la sûreté des cuves des réacteurs à eau légère actuels et/ou qui aideront à définir les cuves des nouvelles générations de réacteur. Ils montrent aussi que l’industrie nucléaire est l’un des secteurs où les solutions techniques sont systématiquement renforcées par une connaissance très fine des phénomènes mis en jeu

An Exergy-based MILP algorithm for Heat Pump Integration in industrial processes

International audienceIndustrial heat pumps are efficient thermodynamic systems able to recover low grade heat and deliver it at higher temperatures (up to 120°C for the current available solutions). They are identified as a very efficient way to reduce primary energy consumption in processes, especially in food & drink or pulp & paper industries. Nevertheless, the optimal integration of multiple heat pumps in a large process with numerous heat fluxes is challenging. The present paper aims at describing an algorithm that was developed for this purpose, based on the GCC (Grand Composite Curve) of Pinch Analysis and on Exergy Theory. The temperature scale of the GCC is divided in areas defined by the Main Pinch Point and Potential local Pinch Points. Then, every potential heat pump is evaluated, absorbing heat in any area for delivering in an upper one. The corresponding heat load and COP are calculated. Exergy cost of remaining cold utilities is calculated with a Carnot based-efficiency, exergy cost of hot utilities according to their nature and temperature. The global exergy cost is used as criteria. Thanks to its formulation, the algorithm may suggest heat pumps solutions in non-obvious areas. The algorithm is tested on a literature case and shows equivalent or better exergy costs in a satisfying calculation time

Solute cluster formation in austenitic and ferritic alloys under ion irradiation: a three-dimensional atom probe characterization

International audienc

Solute cluster formation in austenitic and ferritic alloys under ion irradiation: a three-dimensional atom probe characterization

International audienc

Ascochyta blight development on a new winter pea genotype highly reactive to photoperiod under field conditions

Winter pea suffers from two main types of damage, due to the length of its cycle and climatic conditions (rainfall periods, leaf wetness duration and frost periods): frost and ascochyta blight (Mycosphaerella pinodes). New winter lines resistant to fros