One single static measurement predicts wave localization in complex structures

A recent theoretical breakthrough has brought a new tool, called \emph{localization landscape}, to predict the localization regions of vibration modes in complex or disordered systems. Here, we report on the first experiment which measures the localization landscape and demonstrates its predictive power. Holographic measurement of the static deformation under uniform load of a thin plate with complex geometry provides direct access to the landscape function. When put in vibration, this system shows modes precisely confined within the sub-regions delineated by the landscape function. Also the maxima of this function match the measured eigenfrequencies, while the minima of the valley network gives the frequencies at which modes become extended. This approach fully characterizes the low frequency spectrum of a complex structure from a single static measurement. It paves the way to the control and engineering of eigenmodes in any vibratory system, especially where a structural or microscopic description is not accessible.Comment: 5 pages, 4 figure

Antigen specific activation of cytotoxic CD8+ T cells by Staphylococcus aureus infected dendritic cells

International audienceStaphylococcus aureus ( S. aureus ) is a pathogen associated with a wide variety of diseases, from minor to life-threatening infections. Antibiotic-resistant strains have emerged, leading to increasing concern about the control of S. aureus infections. The development of vaccines may be one way to overcome these resistant strains. However, S. aureus ability to internalize into cells – and thus to form a reservoir escaping humoral immunity – is a challenge for vaccine development. A role of T cells in the elimination of persistent S. aureus has been established in mice but it remains to be established if CD8 + T cells could display a cytotoxic activity against S. aureus infected cells. We examined in vitro the ability of CD8 + T cells to recognize and kill dendritic cells infected with S. aureus. We first evidenced that both primary mouse dendritic cells and DC2.4 cell line can be infected with S. aureus . We then generated a strain of S. aureus expressing a model CD8 epitope and transgenic F5 CD8 + T cells recognizing this model epitope were used as reporter T cells. In response to S. aureus -infected dendritic cells, F5 CD8 + T cells produced IFN-γ in an antigen-specific manner and displayed an increased ability to kill infected cells. Altogether, these results demonstrate that cells infected by S. aureus display bacteria-derived epitopes at their surface that are recognized by CD8 + T cells. This paves the way for the development of CD8 + T cell-based therapies against S. aureus

Generation of a C57BL/6J mouse strain expressing the CD45.1 epitope to improve hematopoietic stem cell engraftment and adoptive cell transfer experiments

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Changes in the Intermediate Water Masses of the Mediterranean Sea During the Last Climatic Cycle—New Constraints From Neodymium Isotopes in Foraminifera

International audienceThe Mediterranean Sea is a semi-enclosed basin characterized by arid conditions and connected to the North Atlantic through the Strait of Gibraltar (sill depth of ∼300 m). This generates a Mediterranean thermohaline circulation where the inflow of relatively fresh and cold surface Atlantic water (AW) is transformed into intermediate and deep waters in the Gulf of Lions, the Adriatic Sea, the Levantine Basin and the Aegean Sea (Robinson et al., 2001; Schroeder et al., 2012). In particular, the Levantine Intermediate Water (LIW) is formed in the Cyprus-Rhodes area from where it spreads westwards into the entire Mediterranean Sea at water depths of between ∼150 and 700 m (Lascaratos et al., 1993; Malanotte-Rizzoli et al., 1999). This overturning circulation is associated with an outflow of saltier and warmer intermediate water into the North Atlantic corresponding to the Mediterranean Outflow Water (MOW) (Robinson et al., 2001; Schroeder et al., 2012). Because the MOW contains up to ∼80% of LIW, the water mass formation in the Levantine Sea plays an important role for the salty outflow to the North Atlantic through the Strait of Gibraltar. A link between the intensification of the MOW and the intensity of the Atlantic Meridional Overturning Circulation (AMOC) has been proposed