AMBRA1 is able to induce mitophagy via LC3 binding, regardless of PARKIN and p62/SQSTM1

Damaged mitochondria are eliminated by mitophagy, a selective form of autophagy whose dysfunction associates with neurodegenerative diseases. PINK1, PARKIN and p62/SQTMS1 have been shown to regulate mitophagy, leaving hitherto ill-defined the contribution by key players in 'general' autophagy. In basal conditions, a pool of AMBRA1 - an upstream autophagy regulator and a PARKIN interactor - is present at the mitochondria, where its pro-autophagic activity is inhibited by Bcl-2. Here we show that, upon mitophagy induction, AMBRA1 binds the autophagosome adapter LC3 through a LIR (LC3 interacting region) motif, this interaction being crucial for regulating both canonical PARKIN-dependent and -independent mitochondrial clearance. Moreover, forcing AMBRA1 localization to the outer mitochondrial membrane unleashes a massive PARKIN- and p62-independent but LC3-dependent mitophagy. These results highlight a novel role for AMBRA1 as a powerful mitophagy regulator, through both canonical or noncanonical pathways

Étude de deux types de ressorts hélicoïdaux fermés : acier et nickel-titane

Cette étude a pour objet de comparer les forces développées par l'étirement de 2 types de ressorts hélicoïdaux fermés : acier et nickel-titane et de rechercher une possible utilisation de l'effet mémoire de forme. Matériel Des ressorts en acier, préparés à partir d'une bobine ont été comparés à des ressorts en nickel-titane tirés au hasard dans deux lots distincts (Ormco). Méthodes 1. Un ressort en acier et un ressort en nickel-titane ont été examinés au microscope électronique à balayage afin d'examiner leur état de surface et de déterminer leur composition chimique. 2. Les températures de transformation cristallographique d'un ressort en nickel-titane de chaque lot ont été déterminées en Calorimétrie Différentielle à Balayage. 3. Les forces restituées après étirement des ressorts ont été mesurées dans 3 situations - à 35° C, - après refroidissement pendant 5 secondes au cryo-spray, - après refroidissement pendant 10 secondes au cryo-spray. Résultats 1. L'état de surface varie selon le métal et les lots de nickel-titane. 2. Les températures de transformation différent entre les deux lots de nickel-titane. 3. En traction, les ressorts en nickel-titane ont un comportement superélastique et homogène. 4. L'effet mémoire de forme n'a pas pu être mis en évidence après le refroidissement des ressorts en nickel-titane

The use of SCC for the containment of high level radioactive waste

Worldwide 10000 m(3) of highly active radioactive waste is being produced each year originating from the most diverse sources. The storage issues arising from this considerable amount is being discussed from country to country. The Belgian concept is founded on the use of cylindrical concrete supercontainers deeply stored inside the geological Boom Clay. This concept is based on a multiple barrier system where every component has its own specific safety function requirements. A self-compacting concrete (SCC) is being considered for the choice of the cementitious buffer, enclosing the radwaste. The use of SCC will ease considerably the precast process and complies with all other requirements regarding strength, durability, chemical interactions,... . A laboratory characterization program, in order to obtain the mechanical and thermal properties of the SCC has been finalised and the data are used to simulate the behaviour of the concrete buffer by using a 2.5D thermal and crack modelling program during the different manufacturing steps of the supercontainer: 1. Fabrication of the concrete, 2. Emplacement of the heat-emitting waste canisters, 3. Filling the remaining annular gap, 4. Closing the lid. Through-going cracks in the concrete buffer, which will considerably ease the transport mechanisms inside the supercontainer, are not expected

Microstructure of surface and subsurface layers of a Ni-Ti shape memory microwire

The microstructure of a 55 µm diameter, cold-worked Ni-Ti microwire is investigated by different transmission electron microscopy techniques. The surface consists of a few hundred nanometer thick oxide layer composed of TiO and TiO₂ with a small fraction of inhomogeneously distributed Ni. The interior of the wire has a core-shell structure with primarily B2 grains in the 1 µm thick shell, and heavily twinned B19' martensite in the core. This core-shell structure can be explained by a concentration gradient of the alloying elements resulting in a structure separation due to the strong temperature dependence of the martensitic start temperature. Moreover, in between the B2 part of the metallic core-shell and the oxide layer, a Ni₃Ti interfacial layer is detected.status: publishe