Diffusion of gold nanoclusters on graphite

We present a detailed molecular-dynamics study of the diffusion and coalescence of large (249-atom) gold clusters on graphite surfaces. The diffusivity of monoclusters is found to be comparable to that for single adatoms. Likewise, and even more important, cluster dimers are also found to diffuse at a rate which is comparable to that for adatoms and monoclusters. As a consequence, large islands formed by cluster aggregation are also expected to be mobile. Using kinetic Monte Carlo simulations, and assuming a proper scaling law for the dependence on size of the diffusivity of large clusters, we find that islands consisting of as many as 100 monoclusters should exhibit significant mobility. This result has profound implications for the morphology of cluster-assembled materials

Quantify osteoarthritis gait at the doctor’s office: a simple pelvis accelerometer based method independent from footwear and aging

The gold standard to evaluate the severity of steoarthritis in the doctor’s office remains clinical scores (Bellamy 2002). The Western Ontario and McMaster Universities (WOMAC) oste- oarthritis index is the most largely used score in rheumatology for lower limb osteoarthritis. It is based on clinical observation and it assesses pain, stiffness, and physical function in patients with hip and knee osteoarthritis. It is valid, reliable, and sen- sitive to evaluate osteoarthritis and adapted to doctor’s office (Bellamy 2002). However, clinical scores are inherently subjective and they depend from the patient’s impression and from the clinician’s interpretation. Gait analysis in modern gait laboratories with force plates and photogrammetry is a good tool to have an objec- tive, quantified, and precise insight in osteoarthritis (Astephen et al. 2008). For practical reasons, skin-mounted inertial sensors are well suited for investigating gait kinematics (Auvinet et al. 2002). In accelerometer-based gait analysis, aging is also known to affect gait parameters (Oberg et al. 1993). To have a clinical measure of osteoarthritis, it is essential to find a technique that is independ- ent from aging. Footwear can also affect walking parameters (Chambon et al. 2014). Since it is too time consuming to ask the patient to take off his shoe for the measurement, it is essential to find a method independent from the shoe type. Walking ten meters go and ten meters back on a level sur- face at comfortable walking speed is a well-suited protocol for clinical situations. This study proposes to test a 3D pelvis accelerometer-based measurement method on a group of 47 patients suffering from lower limb osteoarthritis and 12 asymptomatic subjects. The aim was to see whether the ccelerometer-based method is correlated with the clinical severity of the lower limb osteoarthritis evalu- ated with the WOMAC index. In addition, this study valuates whether the accelerometer-based method is independent of aging on 75 asymptomatic subjects and whether the acceler- ometer-based method is independent from footwear on one asymptomatic subject

Terminal NK cell maturation is controlled by concerted actions of T-bet and Zeb2 and is essential for melanoma rejection

Natural killer (NK) cell maturation is a tightly controlled process that endows NK cells with functional competence and the capacity to recognize target cells. Here, we found that the transcription factor (TF) Zeb2 was the most highly induced TF during NK cell maturation. Zeb2 is known to control epithelial to mesenchymal transition, but its role in immune cells is mostly undefined. Targeted deletion of Zeb2 resulted in impaired NK cell maturation, survival, and exit from the bone marrow. NK cell function was preserved, but mice lacking Zeb2 in NK cells were more susceptible to B16 melanoma lung metastases. Reciprocally, ectopic expression of Zeb2 resulted in a higher frequency of mature NK cells in all organs. Moreover, the immature phenotype of Zeb2(-/-) NK cells closely resembled that of Tbx21(-/-) NK cells. This was caused by both a dependence of Zeb2 expression on T-bet and a probable cooperation of these factors in gene regulation. Transgenic expression of Zeb2 in Tbx21(-/-) NK cells partially restored a normal maturation, establishing that timely induction of Zeb2 by T-bet is an essential event during NK cell differentiation. Finally, this novel transcriptional cascade could also operate in human as T-bet and Zeb2 are similarly regulated in mouse and human NK cells

Mode coupling instability of colliding beams in the HL-LHC

The coupling between the coherent beam-beam modes and the head-tail modes can result in strong instabilities under the effect of electromagnetic wake fields. This mode coupling phenomenon was modelled and observed in the Large Hadron Collider (LHC) for the dipole mode. In the High Luminosity upgrade (HL-LHC), the low β function at the interaction point may generate coupling instabilities of higher-order head-tail modes which would not be stabilised by the transverse feedback. This paper describes the development of an efficient 6D model of the coherent beam-beam interactions in order to assess the beam stability in configurations relevant for the HL-LHC. After having described the limit of the simulation method, we show that the mechanism of Landau damping by the synchrotron sidebands of the incoherent spectrum is sufficient to stabilise the beam in the operational scenario of HL-LHC, including a backup scenario without crab-cavity featuring a large Piwinski angle

un exemple d'adduction d'eau domaniale en haut Gard rhodanien : l'aqueduc privé de la villa de Mayran

International audienc

Un centre domanial dans la vallée de la Tave : la villa de Mayran (Saint-Victor-la-Coste, Gard)

National audienc