Réalisation de micro-résonateurs organiques par procédés hybrides : Nouvelles perspectives en photonique intégrée

L’article consiste en une étude de micro-résonateurs (MRs) sphériques fabriqués à partir d’un matériau organique : le polymère NOA (Northland Optical Adhesive). Les auteurs présentent en un premier lieu le circuit micro fluidique spécialement adapté à la création de gouttes sphériques MRs.L’excitation des modes de galerie permet de déterminer les rayons des sphères. Dans une intégration photonique et pour un meilleur confinement, les sphères sont excitées en utilisant un guide d’onde réalisé par technique de « spin coating » à l’aide de polymère SU8 (bisphénol A d’éther glycide). Le couplage est réalisé à l’aide d’ondes évanescentes circulant du guide vers la sphère. La photographie des sphères excitées (pour deux configurations différentes all-pass ou add-drop) met en évidence les modes optiques situés à la surface des sphères synonymes de modes de galerie. L’analyse spectrale du signal à la sortie du guide met en évidence la présence de pics confirmant l’excitation de cette catégorie de modes au sein de la structure. Ces mesures, à l’aide de l’intervalle spectrale libre permettent de remonter aux diamètres des sphères. Les valeurs déterminées sont en bon accord avec celles mesurées à l’aide de la microscopie optique

Transcriptomic and metabolomic profiles of Zea mays fed with urea and ammonium

The simultaneous presence of different N-forms in the rhizosphere leads to beneficial effects on nitrogen (N) nutrition in plants. Although widely used as fertilizers, the occurrence of cross connection between urea and ammonium nutrition has been scarcely studied in plants. Maize fed with a mixture of urea and ammonium displayed a better N-uptake efficiency than ammonium- or urea-fed plants (Buoso et al., Plant Physiol Biochem, 2021a; 162: 613\u2013623). Through multiomic approaches, we provide the molecular characterization of maize response to urea and ammonium nutrition. Several transporters and enzymes involved in N-nutrition were upregulated by all three N-treatments (urea, ammonium, or urea and ammonium). Already after 1 day of treatment, the availability of different N-forms induced specific transcriptomic and metabolomic responses. The combination of urea and ammonium induced a prompt assimilation of N, characterized by high levels of some amino acids in shoots. Moreover, ZmAMT1.1a, ZmGLN1;2, ZmGLN1;5, ZmGOT1, and ZmGOT3, as well transcripts involved in glycolysis-TCA cycle were induced in roots by urea and ammonium mixture. Depending on N-form, even changes in the composition of phytohormones were observed in maize. This study paves the way to formulate guidelines for the optimization of N fertilization to improve N-use efficiency in maize and therefore limit N-losses in the environment

Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished

A novel deep-UV polymer for integrated photonics: from waveguides structures to taper-waveguides coupled to cascade of multistage resonators used as thermal sensors

International audienceAn overview of current research on integrated photonics based on the new UV210 phot-oresist is given. We report the overall design, fabrication and characterization of waveguides structures, multistage microresonators and their potential as thermal sensors

Comparison of patient-led, fibromyalgia-orientated physical activity and a non-specific, standardised 6-month physical activity program on quality of life in individuals with fibromyalgia: a protocol for a randomised controlled trial

International audienceAbstract Background Exercise has been shown to significantly improve pain and function in individuals with fibromyalgia. Research into the effectiveness of exercise is often based on standardised exercise programmes that are chosen by the investigating clinical research team. However, such programmes may not necessarily be appealing to the participating patients. Furthermore, in addition to being taught exercises, patients with chronic conditions like fibromyalgia also need to learn to manage their condition themselves and so be actively involved in their treatment. The primary aim of this study is to compare the effects of two, 6-month physical activity programs on quality of life in patients with fibromyalgia. One group followed a patient-led, fibromyalgia-orientated programme (experimental) whilst the control group followed a standard, general exercise programme. Methods This protocol is an open-label, two-centre, randomised, controlled superiority trial. Two treatment arms will be compared: an experimental group (patient-led, fibromyalgia-orientated exercise) and a control group (general exercise program). The control group will participate in the exercise programme currently provided in our centre, which involves general, group exercise for patients with various pathologies. The experimental group will be taught the principles of exercise specifically for fibromyalgia during a one-to-one coaching session. They will then be guided in the choice of one or several types of exercise that they enjoy. They will be instructed to perform the exercise according to the recommendations for exercise in fibromyalgia with regard to intensity, duration and frequency. The protocol will last for 6 months; participants will then be followed-up for a further 6 months. They will also be encouraged to continue exercising after the end of the protocol. Outcomes will be evaluated at baseline, 6 and 12 months. The primary outcome will be quality of life (Fibromyalgia Impact Questionnaire) and the secondary outcomes will include measures of pain (including a visual analogue scale and the neuropathic characteristics of the pain), depression (Hospital Anxiety and Depression Scale), kinesiophobia (Tampa scale of kinesiophobia) and adherence (Polar OH1 heart rate monitor). Discussion The results of this study will show if patient-led, fibromyalgia-orientated exercise is more effective than a general exercise programme on fibromyalgia-related outcomes, including quality of life, and on adherence to continued exercise. Trial registration ClinicalTrials.gov NCT03895086 . Registration no. 2018-A02881-54. Registered on 29 March 201