Laser Fabry-Perot verrouillé en longueur d'onde par injection optique pour le réseau d'accès

session orale Lu2 « Amplificateurs et Lasers à semi-conducteurs » [Lu2.2]National audiencePour les futurs réseaux d'accès optique multiplexés en longueur d'onde (de type WDM-PON), des émetteurs optiques bas-coûts et identiques pour chaque abonné sont souhaitables. Ces composants doivent pouvoir être modulés à 10 Gbps, tout en ayant une accordabilité en longueur d'onde. Cette dernière propriété peut-être assurée en verrouillant un laser Fabry-Perot multimode par injection optique. Nous présentons les propriétés d'un tel laser injecté : son efficacité en verrouillage, la réduction du bruit d'intensité et l'amélioration très importante de la fréquence de relaxation

16x2.5 Gbit/s Downstream Transmission in Colorless WDM-PON based on Injection-Locked Fabry-Perot Laser Diode using a single Quantum Dash mode-locked Fabry-Perot laser as multi-wavelength seeding source

technical session OThA " WDM-Access II "International audienceError-free colorless WDM-PON downstream over 25 km for 16 channels with 85 GHz channel spacing is experimentally demonstrated at 2.5 Gbit/s, using an injection-locked Fabry-Perot laser and a quantum dash mode-locked laser as a coherent seeding source

Rifampin use in acute community-acquired meningitis in intensive care units: the French retrospective cohort ACAM-ICU study

Abstract Introduction Bacterial meningitis among critically ill adult patients remains associated with both high mortality and frequent, persistent disability. Vancomycin was added to treatment with a third-generation cephalosporin as recommended by French national guidelines. Because animal model studies had suggested interest in the use of rifampin for treatment of bacterial meningitis, and after the introduction of early corticosteroid therapy (in 2002), there was a trend toward increasing rifampin use for intensive care unit (ICU) patients. The aim of this article is to report on this practice. Methods Five ICUs participated in the study. Baseline characteristics and treatment data were retrospectively collected from charts of patients admitted with a diagnosis of acute bacterial meningitis during a 5-year period (2004–2008). The ICU mortality was the main outcome measure; Glasgow Outcome Scale and 3-month mortality were also assessed. Results One hundred fifty-seven patients were included. Streptococcus pneumoniae and Neisseria meningitidis were the most prevalent causative microorganisms. The ICU mortality rate was 15 %. High doses of a cephalosporin were the most prevalent initial antimicrobial treatment. The delay between admission and administration of the first antibiotic dose was correlated with ICU mortality. Rifampin was used with a cephalosporin for 32 patients (ranging from 8 % of the cohort for 2004 to 30 % in 2008). Administration of rifampin within the first 24 h of hospitalization could be associated with a lower ICU survival. Statistical association between such an early rifampin treatment and ICU mortality reached significance only for patients with pneumococcal meningitis (p=0.031) in univariate analysis, but not in the logistic model. Conclusions We report on the role of rifampin use for patients with community-acquired meningitis, and the results of this study suggest that this practice may be associated with lower mortality in the ICU. Nevertheless, the only independent predictors of ICU mortality were organ failure and pneumococcal infection. Further studies are required to confirm these results and to explain how rifampin use would reduce mortality. </jats:sec

Noninvasive mechanical ventilation in high-risk pulmonary infections: a clinical review

The aim of this article was to review the role of noninvasive ventilation (NIV) in acute pulmonary infectious diseases, such as severe acute respiratory syndrome (SARS), H1N1 and tuberculosis, and to assess the risk of disease transmission with the use of NIV from patients to healthcare workers. We performed a clinical review by searching Medline and EMBASE. These databases were searched for articles on "clinical trials" and "randomised controlled trials". The keywords selected were non-invasive ventilation pulmonary infections, influenza-A (H1N1), SARS and tuberculosis. These terms were cross-referenced with the following keywords: health care workers, airborne infections, complications, intensive care unit and pandemic. The members of the International NIV Network examined the major results regarding NIV applications and SARS, H1N1 and tuberculosis. Cross-referencing mechanical ventilation with SARS yielded 76 studies, of which 10 studies involved the use of NIV and five were ultimately selected for inclusion in this review. Cross-referencing with H1N1 yielded 275 studies, of which 27 involved NIV. Of these, 22 were selected for review. Cross-referencing with tuberculosis yielded 285 studies, of which 15 involved NIV and from these seven were selected. In total 34 studies were selected for this review. NIV, when applied early in selected patients with SARS, H1N1 and acute pulmonary tuberculosis infections, can reverse respiratory failure. There are only a few reports of infectious disease transmission among healthcare workers

Colorless Components for WDM-based Optical Access Networks

Section B "PHOTONICS & LASERS AND APPLICATIONS" [B-45]International audienceThis paper presents our work carried out in the colorless-component technologies for high bit-rate optical access networks, which are based on WDM-PON (wavelength division multiplexed passive optical networks). The colorless concept consists in using identical and wavelength-independent components that will act as the generic transmitter in WDM-PON systems. The transmitted wavelength is imposed, for each colorless component, by an external optical signal. Our studies include two types of colorless components: The Injection-Locked Fabry-Perot laser (IL-FP) and the Reflective Electro-Absorption Modulator integrated with a Semiconductor Optical Amplifier (REAM-SOA). For the IL-FP, the properties of the component strongly depend on the injected optical signal. We demonstrate the improvement by injection-locking of the laser's performances in terms of intensity noise, chirp and bandwidth. For the REAM-SOA, the static properties such as reflection gain and noise characteristic are examined. We demonstrate the feasibility of the REAM-SOA in a transmission experiment in a PON configuration at 10 Gbps with up to 25 km of SMF, using remote modulation technique

Inhibition du canal SK3 et du développement de métastases par un ether-lipide synthétique

Il a été mis en évidence que le canal SK3 est un médiateur de la migration de cellules cancéreuses mammaires, une propriété essentielle à la formation de métastases. Par ailleurs, ce canal est inhibé par l édelfosine, un éther-lipide ayant des propriétés anti-tumorales in vitro mais son usage en clinique a été abandonné en raison d effets secondaires. Une première partie de ce travail a permis de déterminer les parties de l édelfosine nécessaires à l inhibition du canal SK3 et de la migration cellulaire. Ceci nous a permis de sélectionner l Ohmline (1-O-Hexadécyl-2-O-Méthyl-sn-glycéro-lactose), un analogue non toxique de l édelfosine qui conserve son activité inhibitrice de SK3 et de la migration. Dans un deuxième temps, nous avons testé ce lipide dans un modèle murin de développement tumoral et nous avons montré qu il réduisait le développement des métastases sans modifier la tumeur primaire. En conclusion, nous avons décrit l Ohmline qui est le premier inhibiteur lipidique de SK3 et qui pourrait devenir le premier membre d une famille de composés lipidiques inhibiteurs de la formation de métastases.It has been shown that SK3 channel was a mediator of breast cancer cells migration, a fundamental property for metastasis formation. In addition, edelfosine inhibits SK3 channel. This ether-lipid owns a high anti cancerous potential in vitro but its clinical use was hampered by some side effects, Firstly, we showed the structural parts of edelfosine required for SK3 channel inhibition and cell motility inhibition. Moreover, we selected Ohmline (1-O-Hexadécyl-2-O-Méthyl-sn-glycéro-lactose), an edlefosine s analogue that preserves SK3 channel and motility inhibitory properties. Secondly, we evaluated this lipid on tumor development in nude mice model. We showed that this lipid reduces metastasis formation without effect on primary tumor. To conclude, we described Ohmline, the first lipid inhibitor of SK3. This compound should become the first member of a new family of metastasis lipid inhibitors.TOURS-Bibl.électronique (372610011) / SudocSudocFranceF

Pyk2 modulates hippocampal excitatory synapses and contributes to cognitive deficits in a Huntington's disease model.

The structure and function of spines and excitatory synapses are under the dynamic control of multiple signalling networks. Although tyrosine phosphorylation is involved, its regulation and importance are not well understood. Here we study the role of Pyk2, a non-receptor calcium-dependent protein-tyrosine kinase highly expressed in the hippocampus. Hippocampal-related learning and CA1 long-term potentiation are severely impaired in Pyk2-deficient mice and are associated with alterations in NMDA receptors, PSD-95 and dendritic spines. In cultured hippocampal neurons, Pyk2 has autophosphorylation-dependent and -independent roles in determining PSD-95 enrichment and spines density. Pyk2 levels are decreased in the hippocampus of individuals with Huntington and in the R6/1 mouse model of the disease. Normalizing Pyk2 levels in the hippocampus of R6/1 mice rescues memory deficits, spines pathology and PSD-95 localization. Our results reveal a role for Pyk2 in spine structure and synaptic function, and suggest that its deficit contributes to Huntington's disease cognitive impairments

Role of the ERK pathway in psychostimulant-induced locomotor sensitization

BACKGROUND: Repeated exposure to psychostimulants results in a progressive and long-lasting facilitation of the locomotor response that is thought to have implications for addiction. Psychostimulants and other drugs of abuse activate in specific brain areas extracellular signal-regulated kinase (ERK), an essential component of a signaling pathway involved in synaptic plasticity and long-term effects of drugs of abuse. Here we have investigated the role of ERK activation in the behavioral sensitization induced by repeated administration of psychostimulants in mice, using SL327, a brain-penetrating selective inhibitor of MAP-kinase/ERK kinase (MEK), the enzyme that selectively activates ERK. RESULTS: A dose of SL327 (30 mg/kg) that reduced the number of activated ERK-positive neurons by 62 to 89% in various brain areas, had virtually no effect on the spontaneous locomotor activity or the acute hyperlocomotion induced by cocaine or D-amphetamine. Pre-treatment with SL327 (30 mg/kg) prior to each drug administration prevented the locomotor sensitization induced by repeated injections of D-amphetamine or cocaine. The SL327 pre-treatment abolished also conditioned locomotor response of mice placed in the context previously paired with cocaine or D-amphetamine. In contrast, SL327 did not alter the expression of sensitized response to D-amphetamine or cocaine. CONCLUSION: Altogether these results show that ERK has a minor contribution to the acute locomotor effects of psychostimulants or to the expression of sensitized responses, whereas it is crucial for the acquisition of locomotor sensitization and psychostimulant-conditioned locomotor response. This study supports the important role of the ERK pathway in long-lasting behavioral alterations induced by drugs of abuse

About the Electrospray Ionization Source in Mass Spectrometry: Electrochemistry and On-chip Reactions

The present work shows that the electrochemical properties of electrospray ionization (ESI) can be used to add functions to the process. As example, we show how the choice of the electrode material can be used to study interactions between metal ions and biomolecules in mass spectrometry (MS). In positive ionization MS, an electrospray device acts as anode, which implies oxidation reactions. Sacrificial electrodes (made of copper or zinc) are used to supply the electrospray current and to produce cations that are able to react on-line with compounds of interest. Thus, the interactions between copper ions and ligands or peptides were investigated by using a copper electrode. Another example is the in situ electrogeneration of a dinuclear zinc(II) complex for the mass tagging of phosphopeptides when working with a zinc electrode. In order to perform these reactions on the same microchip, a dual-channel microsprayer was used, where one channel was dedicated to the tag electrogeneration and the other to the infusion of a phosphopeptides solution. Finally, this dual-channel microsprayer was used to study complexation at liquid-liquid interfaces in biphasic ESI-MS, such as thioether crowns and lead ions or peptides and phospholipids complexes. These examples illustrate the use of electrochemistry and on-chip reactions in ESI-MS analysis