Spatiotemporal pulses in a liquid crystal optical oscillator

A nonlinear optical medium results by the collective orientation of liquid crystal molecules tightly coupled to a transparent photoconductive layer. We show that such a medium can give a large gain, thus, if inserted in a ring cavity, it results in an unidirectional optical oscillator. Dynamical regimes with many interacting modes are made possible by the wide transverse size and the high nonlinearity of the liquid crystals. We show the generation of spatiotemporal pulses, coming from the random superposition of many coexisting modes with different frequencies

Phase modulators ands splitting network on Si PIC coherent fiber beam combining

Coherent beam combining (CBC) of fiber lasers provide an attractive mean of reaching high output laser power by scaling up the available energy while keeping fiber intrinsic advantages of compactness, reliability, efficiency, and beam quality. In CBC architectures, the power of a master oscillator (MO) is divided into N fibers that are amplified individually. The phase perturbations between channels can be measured using various techniques [1-3] and are corrected by individual phase modulators placed on each fiber before the amplification. In this Communication, we present a Silicon PIC integrating a 1:16 channels splitting network and thermal phase modulators array with low electrical power consumption and a bandwidth compatible with CBC requirements. In our CBC system, a 1.55µm CW master oscillator directly feeds the Silicon chip through a grating coupler, as shown in Fig.1(a). The power of the master oscillator is first split on chip into 16 channels, each of which including a thermal phase modulator. The outputs of the 16 waveguides are collectively out-coupled from the chip using a PM optical fiber array aligned and glued onto the PIC’s output grating couplers array [4]. At the other end of fiber array, the 16 fiber outputs are arranged in a 4 by 4 squared lattice, and collimated by a microlens array to form 16 collimated and parallel beamlets. The phase distribution from channel to channel is derived from the fringe pattern resulting from the collimated beamlets interfering with a reference plane wave on a camera. This signal is fed back to drive the PIC’s phase modulators in order to phase lock the 16 fiber

Silicon photonics frequency shifter based on I&Q dual Mach-Zehnder modulator

We present a fully CMOS compatible frequency shifter device, in a I&Q dual Mach-Zehnder architecture. Frequency shift up to 410 MHz are obtained, with carrier and image sideband extinction from 27 to 51 dB

Phase modulators and splitting network on Si PIC for coherent fiber beam combining

Coherent beam combining (CBC) of fiber lasers provide an attractive mean of reaching high output laser power by scaling up the available energy while keeping fiber intrinsic advantages of compactness, reliability, efficiency, and beam quality. In CBC architectures, the power of a master oscillator (MO) is divided into N fibers that are amplified individually. The phase perturbations between channels can be measured using various techniques [1-3] and are corrected by individual phase modulators placed on each fiber before the amplification. In this Communication, we present a Silicon PIC integrating a 1:16 channels splitting network and thermal phase modulators array with low electrical power consumption and a bandwidth compatible with CBC requirements

Childhood lead exposure in France: benefit estimation and partial cost-benefit analysis of lead hazard control

<p>Abstract</p> <p>Background</p> <p>Lead exposure remains a public health concern due to its serious adverse effects, such as cognitive and behavioral impairment: children younger than six years of age being the most vulnerable population. In Europe, the lead-related economic impacts have not been examined in detail. We estimate the annual costs in France due to childhood exposure and, through a cost benefit analysis (CBA), aim to assess the expected social and economic benefits of exposure abatement.</p> <p>Methods</p> <p>Monetary benefits were assessed in terms of avoided national costs. We used results from a 2008 survey on blood-lead (B-Pb) concentrations in French children aged one to six years old. Given the absence of a threshold concentration being established, we performed a sensitivity analysis assuming different hypothetical threshold values for toxicity above 15 μg/L, 24 μg/L and 100 μg/L. Adverse health outcomes of lead exposure were translated into social burden and economic costs based on literature data from literature. Direct health benefits, social benefits and intangible avoided costs were included. Costs of pollutant exposure control were partially estimated in regard to homes lead-based paint decontamination, investments aiming at reducing industrial lead emissions and removal of all lead drinking water pipes.</p> <p>Results</p> <p>The following overall annual benefits for the three hypothetical thresholds values in 2008 are: €22.72 billion, €10.72 billion and €0.44 billion, respectively. Costs from abatement ranged from €0.9 billion to 2.95 billion/year. Finally, from a partial CBA of lead control in soils and dust the estimates of total net benefits were € 3.78 billion, € 1.88 billion and €0.25 billion respectively for the three hypothesized B-Pb effect values.</p> <p>Conclusions</p> <p>Prevention of childhood lead exposure has a high social benefit, due to reduction of B-Pb concentrations to levels below 15 μg/L or 24 μg/L, respectively. Reducing only exposures above 100 μg/L B-Pb has little economic impact due to the small number of children who now exhibit such high exposure levels. Prudent public policies would help avoiding future medical interventions, limit the need for special education and increase future productivity, and hence lifetime income for children exposed to lead.</p

In vivo combination of human anti-envelope glycoprotein E2 and -Claudin-1 monoclonal antibodies for prevention of hepatitis C virus infection

Despite the development of direct-acting antivirals (DAAs), hepatitis C virus (HCV) infection remains a major cause for liver disease and cancer worldwide. Entry inhibitors block virus host cell entry and, therefore, prevent establishment of chronic infection and liver disease. Due to their unique mechanism of action, entry inhibitors provide an attractive antiviral strategy in organ transplantation. In this study, we developed an innovative approach in preventing HCV infection using a synergistic combination of a broadly neutralizing human monoclonal antibody (HMAb) targeting the HCV E2 protein and a host-targeting anti-claudin 1 (CLDN1) humanized monoclonal antibody. An in vivo proof-of-concept study in human liver-chimeric FRG-NOD mice proved the efficacy of the combination therapy at preventing infection by an HCV genotype 1b infectious serum. While administration of individual antibodies at lower doses only showed a delay in HCV infection, the combination therapy was highly protective. Furthermore, the combination proved to be effective in preventing infection of primary human hepatocytes by neutralization-resistant HCV escape variants selected during liver transplantation, suggesting that a combination therapy is suited for the neutralization of difficult-to-treat variants. In conclusion, our findings suggest that the combination of two HMAbs targeting different steps of virus entry improves treatment efficacy while simultaneously reducing treatment duration and costs. Our approach not only provides a clinical perspective to employ HMAb combination therapies to prevent graft re-infection and its associated liver disease but may also help to alleviate the urgent demand for organ transplants by allowing the transplantation of organs from HCV-positive donors

Standardisation des centrales nucléaires françaises à eau légère

Facteur essentiel de réduction des délais et des coûts et aussi facteur de sûreté et de fiabilité, la standardisation est une des caractéristiques du programme français de construction de centrales nucléaires. Après avoir évoqué ses avantages et indiqué les éléments, d'ordre technique ou administratif, susceptibles de lui poser des limites, l'auteur analyse les méthodes et moyens engagés, en France, pour mettre en œuvre une action volontaire et rigoureuse de standardisation des centrales nucléaires

Prenatal diagnosis of urinary malformations: results in a series of 93 consecutive cases.

OBJECTIVE: To evaluate the pertinence of prenatal diagnosis in cases of congenital uropathy. STUDY DESIGN: Retrospective evaluation over a period of 6.5 years. METHOD: 93 cases were involved in the comparison of prenatal ultrasonographic diagnosis with neonatal findings, autopsy results, and follow-up data. RESULTS: 33 fetuses had renal parenchymal lesions, 44 had excretory system lesions, and 6 had bladder and/or urethral lesions. Seventy-three pregnancies lead to live births. Eighteen terminations of pregnancy were performed on the parents' request for extremely severe malformations. Two intrauterine deaths were observed, and two infants died in the postnatal period. Prenatal diagnosis was obtained at an average of 27 weeks gestation. Diagnostic concordance was excellent in 82% and partial in 12% of cases with renal parenchymal lesions; the false-positive rate was 6%. For excretory system lesions, concordance was excellent in 87% and partial in 7.4% of cases, with a false-positive rate of 5.6%. Finally, concordance was excellent in 100% of cases of bladder and/or urethral lesions. The overall rate of total concordance was 86%. Partial concordance cases consisted of malformations different from those previously diagnosed, but prenatal diagnosis nevertheless lead to further investigations in the neonatal period and to proper management. The false-positive diagnoses (5.4%) never lead to termination of pregnancy. CONCLUSION: Prenatal diagnosis of congenital uropathy is effective. A third-trimester ultrasonographic examination is necessary to ensure proper neonatal management, considering that the majority of cases are diagnosed at this gestational age