On the uniqueness of the solution of the two-dimensional Navier-Stokes equation with a Dirac mass as initial vorticity

We propose two different proofs of the fact that Oseen's vortex is the unique solution of the two-dimensional Navier-Stokes equation with a Dirac mass as initial vorticity. The first argument, due to C.E. Wayne and the second author, is based on an entropy estimate for the vorticity equation in self-similar variables. The second proof is new and relies on symmetrization techniques for parabolic equations.Comment: 9 pages, no figur

Role of triadin in the organization of reticulum membrane at the muscle triad.

International audienceThe terminal cisternae represent one of the functional domains of the skeletal muscle sarcoplasmic reticulum (SR). They are closely apposed to plasma membrane invaginations, the T-tubules, with which they form structures called triads. In triads, the physical interaction between the T-tubule-anchored voltage-sensing channel DHPR and the SR calcium channel RyR1 is essential because it allows the depolarization-induced calcium release that triggers muscle contraction. This interaction between DHPR and RyR1 is based on the peculiar membrane structures of both T-tubules and SR terminal cisternae. However, little is known about the molecular mechanisms governing the formation of SR terminal cisternae. We have previously shown that ablation of triadins, a family of SR transmembrane proteins that interact with RyR1, induced skeletal muscle weakness in knockout mice as well as a modification of the shape of triads. Here we explore the intrinsic molecular properties of the longest triadin isoform Trisk 95. We show that when ectopically expressed, Trisk 95 can modulate reticulum membrane morphology. The membrane deformations induced by Trisk 95 are accompanied by modifications of the microtubule network organization. We show that multimerization of Trisk 95 by disulfide bridges, together with interaction with microtubules, are responsible for the ability of Trisk 95 to structure reticulum membrane. When domains responsible for these molecular properties are deleted, anchoring of Trisk 95 to the triads in muscle cells is strongly decreased, suggesting that oligomers of Trisk 95 and microtubules contribute to the organization of the SR terminal cisternae in a triad

Campylobacter Antimicrobial Drug Resistance among Humans, Broiler Chickens, and Pigs, France

We describe isolates from human Campylobacter infection in the French population and the isolates' antimicrobial drug resistance patterns since 1986 and compare the trends with those of isolates from broiler chickens and pigs from 1999 to 2004. Among 5,685 human Campylobacter isolates, 76.2% were C. jejuni, 17.2% C. coli, and 5.0% C. fetus. Resistance to nalidixic acid increased from 8.2% in 1990 to 26.3% in 2004 (p<10-3), and resistance to ampicillin was high over time. Nalidixic acid resistance was greater for C. coli (21.3%) than for C. jejuni (14.9%, p<10-3). C. jejuni resistance to ciprofloxacin in broilers decreased from 31.7% in 2002 to 9.0% in 2004 (p = 0.02). The patterns of resistance to quinolones and fluoroquinolones were similar between 1999 and 2004 in human and broiler isolates for C. jejuni. These results suggest a potential benefit of a regulation policy limiting use of antimicrobial drugs in food animals

In vitro and in vivo intracellular delivery of quantum dots by maurocalcine

International audienceMaurocalcine is a new member of the increasing family of cell penetrating peptides. We report for the first time that this peptide is able to deliver quantum dots inside a variety of cells, both in vitro and in vivo. In vivo, maurocalcine produces intracellular delivery of the nanoparticles without affecting the relative distribution of quantum dots within organs. The data stress out that maurocalcine can be used for intracellular delivery of functionalised nanoparticles in vivo

The French Emergency Department OSCOUR Network: Evaluation After a 10-year Existence

Implemented 10 years ago, the French syndromic surveillance system Oscour, based on emergency departments, has been assessed using four major evaluation criteria in syndromic surveillance: stability and regularity of data transmission, the coverage at the national level, data quality, particularly for medical information and the utility of the system for the public health surveillance. In 2014, about 40,000 daily attendances are extracted automatically from 600 ED departments located all over the territory, covering 80% of the national attendances. About 12,800 different ICD10 codes have been used in 2013, enabling a large public health surveillance

Decoding plant pathogen strategies: exploring effector structural insights for enhanced plant resistance

International audienceThe main strategy to control the fungus Leptosphaeria maculans, the causal agent of stem canker in Brassica napus, is genetic control by plant varieties carrying resistance (R) proteins. However, the massive deployment of a single source of resistance in the fields exerts strong selection pressures towards pathogen populations, leading to the rapid breakdown of the resistance. Recently, advances in effector repertoire prediction, in effector protein heterologous production and structural prediction algorithms have resulted in the identification of several effector families in L. maculans, these families being also present in other plant pathogenic fungi, mainly from the Dotheomycetes and Sordariomycetes. Furthermore, some of the structural analogues identified both in L. maculans and other plant pathogenic fungi share conserved functions during plant infection, suggesting an interesting evolutionary model. In addition, using transcriptomic data collected along the L. maculans life-cycle highlighted expression waves of distinct structural families, suggesting a striking coordination of them during the infection process. Here, we will review the recent advances in structural prediction / structure determination among L. maculans secretome and their implication to gain insight into the putative functions of candidate effectors. We will also propose possible strategies to improve resistance management or increase R proteins recognition spectrum using structural effector families