178 research outputs found

    Coherent combining of mid-infrared difference frequency generators

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    International audienceWe report what is, to the best of our knowledge, the first experimental demonstration of coherent combining of two mid-infrared difference frequency generators by active phase control in continuous-wave regime. Using the phase relation that is inherent to the nonlinear process, we are able to phase-lock and combine the idler waves by the sole phase control of one of the pump waves. This control is done by an all fiber electro-optic modulator. Combining is achieved with an excellent efficiency with a residual phase error of λ/28

    A Monoselective Sphingosine-1-Phosphate Receptor-1 Agonist Prevents Allograft Rejection in a Stringent Rat Heart Transplantation Model

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    SummaryFTY720 is an immunomodulator with demonstrated efficacy in a phase II trial of relapsing multiple sclerosis. FTY720-phosphate, the active metabolite generated upon phosphorylation in vivo, acts as a potent agonist on four of the five known sphingosine-1-phosphate (S1P1) receptors. AUY954, an aminocarboxylate analog of FTY720, is a low nanomolar, monoselective agonist of the S1P1 receptor. Due to its selectivity and pharmacokinetic profile, AUY954 is an excellent pharmacological probe of S1P1-dependent phenomena. Oral administration of AUY954 induces a profound and reversible reduction of circulating lymphocytes and, in combination with RAD001 (Certican/Everolimus, an mTOR inhibitor), is capable of prolonging the survival of cardiac allografts in a stringent rat transplantation model. This demonstrates that a selective agonist of the S1P1 receptor is sufficient to achieve efficacy in an animal model of transplantation

    On the use of systematic reviews to inform environmental policies

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    AbstractEnvironmental research varies in its methodological quality, degree of bias, and relevance to policy questions. Using this heterogeneous, and sometimes polarised, research to inform environmental policies can be challenging. Policy-making in the healthcare field sometimes uses systematic reviews (SRs) to tackle these issues and present a comprehensive, policy-neutral, transparent and reproducible synthesis of the evidence. However, there is less familiarity with SRs in the environmental field. The aim of this article is to: (1) summarise the process of conducting SRs, using best practice methods from the healthcare field as an example, (2) explain the rationale behind each stage of conducting a SR, and (3) examine the prospects and challenges of using SRs to inform environmental policy. We conclude that existing SR protocols from healthcare can be, and have been, applied successfully to environmental research but some adaptations could improve the process. The literature search stage could be expedited by standardising the reporting and indexing of environmental studies, equivalent to that in the healthcare field. The consistency of the study appraisal stage of SRs could be augmented by refining the existing quality assessment tools used in the healthcare field, enhancing their ability to discriminate quality and risk of bias in non-randomised studies. Ultimately, the strength of evidence within SRs on environmental topics could be improved through more widespread use of randomised controlled trials as a research method, owing to their inherently lower risk of bias when conducted according to best practice

    Suberin plasticity to developmental and exogenous cues is regulated by a set of MYB transcription factors

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    Suberin is a hydrophobic biopolymer that can be deposited at the periphery of cells, forming protective barriers against biotic and abiotic stress. In roots, suberin forms lamellae at the periphery of endodermal cells where it plays crucial roles in the control of water and mineral transport. Suberin formation is highly regulated by developmental and environmental cues. However, the mechanisms controlling its spatiotemporal regulation are poorly understood. Here, we show that endodermal suberin is regulated independently by developmental and exogenous signals to fine tune suberin deposition in roots. We found a set of four MYB transcription factors (MYB41, MYB53, MYB92 and MYB93), that are regulated by these two signals, and are sufficient to promote endodermal suberin. Mutation of these four transcription factors simultaneously through genome editing, lead to a dramatic reduction of suberin formation in response to both developmental and environmental signals. Most suberin mutants analyzed at physiological levels are also affected in another endodermal barrier made of lignin (Casparian strips), through a compensatory mechanism. Through the functional analysis of these four MYBs we generated plants allowing unbiased investigations of endodermal suberin function without accounting for confounding effects due to Casparian strip defects, and could unravel specific roles of suberin in nutrient homeostasis
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