Development of a Portable Device for Thermoelectrical Power Measurement—Application to the Inspection of Duplex Stainless Steel Components

Some cast components of the primary loop of French Pressurized Water Reactors are made of cast duplex stainless steels. The mechanical characteristics of these components, working in the temperature range from 285°C to 325°C, may be altered by thermal aging : the hardness of the materials increases whereas its toughness decreases with aging time and temperature. The metallurgical explanation of this phenomena is the unmixing of the ferritic Fe-Cr-Ni solid solution by spinodal decomposition and the precipitation of intermetallic G-phase particles rich in nickel and silicium [1]

Solution Structures of a Cyanobacterial Metallochaperone: INSIGHT INTO AN ATYPICAL COPPER-BINDING MOTIF *

The Atx1 copper metallochaperone from Synechocystis PCC 6803, ScAtx1, interacts with two P(1)-type copper ATPases to supply copper proteins within intracellular compartments, avoiding ATPases for other metals en route. Here we report NMR-derived solution structures for ScAtx1. The monomeric apo form has a betaalphabetabetaalpha fold with backbone motions largely restricted to loop 1 containing Cys-12 and Cys-15. The tumbling rate of Cu(I)ScAtx1 (0.1-0.8 mm) implies dimers. Experimental restraints are satisfied by symmetrical dimers with Cys-12 or His-61, but not Cys-15, invading the copper site of the opposing subunit. A full sequence of copper ligands from the cell surface to thylakoid compartments is proposed, considering in vitro homodimer liganding to mimic in vivo liganding in ScAtx1-ATPase heterodimers. A monomeric high resolution structure for Cu(I)ScAtx1, with Cys-12, Cys-15, and His-61 as ligands, is calculated without violations despite the rotational correlation time. (2)J(NH) couplings in the imidazole ring of His-61 establish coordination of N(epsilon2) to copper. His-61 is analogous to Lys-65 in eukaryotic metallochaperones, stabilizing Cu(I)S(2) complexes but by binding Cu(I) rather than compensating charge. Cys-Cys-His ligand sets are an emergent theme in some copper metallochaperones, although not in related Atx1, CopZ, or Hah1. Surface charge (Glu-13) close to the metal-binding site of ScAtx1 is likely to support interaction with complementary surfaces of copper-transporting ATPases (PacS-Arg-11 and CtaA-Lys-14) but to discourage interaction with zinc ATPase ZiaA and so inhibit aberrant formation of copper-ZiaA complexes

Bases anatomiques indispensables à l'interprétation des opacifications canalaires pancréatiques

L'auteur tire les conclusions de l'étude de 250 blocs duodéno-pancréatiques. La petite caroncule est toujours implantée au-dessus et en avant de la grande caroncule. Le 6 dispositions anatomiques possibles sont présentées avec leurs fréquences respectives

Development of a Portable Device for Thermoelectrical Power Measurement—Application to the Inspection of Duplex Stainless Steel Components

Some cast components of the primary loop of French Pressurized Water Reactors are made of cast duplex stainless steels. The mechanical characteristics of these components, working in the temperature range from 285°C to 325°C, may be altered by thermal aging : the hardness of the materials increases whereas its toughness decreases with aging time and temperature. The metallurgical explanation of this phenomena is the unmixing of the ferritic Fe-Cr-Ni solid solution by spinodal decomposition and the precipitation of intermetallic G-phase particles rich in nickel and silicium [1].</p