An 11.6 Micron Keck Search For Exozodiacal Dust

We have begun an observational program to search nearby stars for dust disks that are analogous to the disk of zodiacal dust that fills the interior of our solar system. We imaged six nearby main-sequence stars with the Keck telescope at 11.6 microns, correcting for atmosphere-induced wavefront aberrations and deconvolving the point spread function via classical speckle analysis. We compare our data to a simple model of the zodiacal dust in our own system based on COBE/DIRBE observations and place upper limits on the density of exozodiacal dust in these systems.Comment: 10 pages, figure1, figure2, figure3, and figures 4a-

Wavelength-scale stationary-wave integrated Fourier-transform spectrometry

Spectrometry is a general physical-analysis approach for investigating light-matter interactions. However, the complex designs of existing spectrometers render them resistant to simplification and miniaturization, both of which are vital for applications in micro- and nanotechnology and which are now undergoing intensive research. Stationary-wave integrated Fourier-transform spectrometry (SWIFTS)-an approach based on direct intensity detection of a standing wave resulting from either reflection (as in the principle of colour photography by Gabriel Lippmann) or counterpropagative interference phenomenon-is expected to be able to overcome this drawback. Here, we present a SWIFTS-based spectrometer relying on an original optical near-field detection method in which optical nanoprobes are used to sample directly the evanescent standing wave in the waveguide. Combined with integrated optics, we report a way of reducing the volume of the spectrometer to a few hundreds of cubic wavelengths. This is the first attempt, using SWIFTS, to produce a very small integrated one-dimensional spectrometer suitable for applications where microspectrometers are essential

Future development of apricot blossom blight under climate change in Southern France

International audienceClimate change will have several consequences for agro-systems, one of which will concern changes to the development of pathogens. Because of the losses it causes, particularly in organic farming, Monilinia laxa is an important pathogen affecting apricot crops. This study focuses on the consequences of climate change regarding blossom and twig blight (Monilinia laxa) of apricot. To achieve this, a Climatic Index of cumulated Blight risk (CIB) was built, to obtain the weighted sum of blossom blight incidence throughout the blooming period. An epidemiological model to calculate the incidence of blossom blight during every potentially infectious episode and based on biological parameters, was calibrated using a trap pot experiment where trees were placed in orchards and subject to various meteorological conditions. The CIB derived from this model was evaluated on field data, and was shown to be a robust and useful tool to predict the effects of climate change on the development of apricot blight. Then, using the CIB with a phenological model to predict blooming periods in the future, we estimated the risks of apricot blight until 2100 on four contrasted apricot cultivars and in three geographical zones under climate change scenarios RCP 4.5 and 8.5. This study revealed different effects of climate change depending on the cultivar and altitude. Apricot trees would bloom earlier (up to a difference of 50 days between 1950 and 2100) under climate change. Under the combined effects of these shifts of blooming period and changing climatic conditions, late cultivars such as Bergarouge might see a reduction in the risk of blossom blight (down to 31%) because of warmer but dryer blooming periods. Other varieties (e.g.: Bergeron) could experience an increase in this risk by up to 27% with a shift of the blooming period towards rainier conditions at the highest altitudes. The results of this study could be used to anticipate future changes as well as be used at present as a decision-support tool for farmers

Effect of extracranial lesion severity on outcome of endovascular thrombectomy in patients with anterior circulation tandem occlusion: analysis of the TITAN registry

Introduction Endovascular treatment (EVT) for tandem occlusion (TO) of the anterior circulation is complex but effective. The effect of extracranial internal carotid artery (EICA) lesion severity on the outcomes of EVT is unknown. In this study we investigated the effect of EICA lesion severity on the outcomes of tandem occlusion EVT. Methods A multicenter retrospective TITAN (Thrombectomy In TANdem lesions) study that included 18 international endovascular capable centers was performed. Patients who received EVT for atherosclerotic TO with or without EICA lesion intervention were included. Patients were divided into two groups based on the EICA lesion severity (high-grade stenosis (>= 90% North American Symptomatic Carotid Endarterectomy Trial) vs complete occlusion). Outcome measures included the 90-day clinical outcome (modified Rankin Scale score (mRS)), angiographic reperfusion (modified Thrombolysis In Cerebral Ischemia (mTICI) at the end of the procedure), procedural complications, and intracranial hemorrhage at 24 hours follow-up. Results A total of 305 patients were included in the study, of whom 135 had complete EICA occlusion and 170 had severe EICA stenosis. The EICA occlusion group had shorter mean onset-to-groin time (259 +/- 120 min vs 305 +/- 202 min;p=0.037), more patients with diabetes, and fewer with hyperlipidemia. With respect to the outcome, mTICI 2b-3 reperfusion was lower in the EICA occlusion group (70% vs 81%;p=0.03). The favorable outcome (90-day mRS 0-2), intracerebral hemorrhage and procedural complications were similar in both groups. Conclusion Atherosclerotic occlusion of the EICA in acute tandem strokes was associated with a lower rate of mTICI 2b-3 reperfusion but similar functional and safety outcomes when compared with high-grade EICA stenosis

Impact of the Thrombectomy Trials on the Management and Outcome of Large Vessel Stroke: Data From the Lyon Stroke Center

Introduction: Randomized trials (RT) have recently validated the superiority of thrombectomy over standard medical care, including intravenous thrombolysis (IVT). However, data on their impact on routine clinical care remains scarce.Methods: Using a prospective observational registry, we assessed: (1) the clinical and radiological characteristics of all consecutive patients treated with thrombectomy; (2) the outcome of all patients with M1 occlusion (treated with thrombectomy or IVT alone). Two periods were compared: before (2013–2014) and after (2015–2016) the publication of RT.Results: Endovascular procedures significantly increased between the two periods (N = 82 vs. 314, p < 0.0001). In 2015–2016, patients were older (median [IQR]: 69 [57-80]; vs. 66 [53-74]; p = 0.008), had shorter door-to-clot times (69 [47-95]; vs. 110 [83-155]; p < 0.0001) resulting in a trend toward shorter delay from symptom onset to reperfusion (232 [185-300]; vs. 250 [200-339]; p = 0.1), with higher rates of reperfusion (71 vs. 48%; p = 0.0001). Conversely, no significant differences in baseline NIHSS scores, ASPECTS, delay to IVT or intracranial hemorrhage were found. In 2015–2016, patients with M1 occlusion were treated with thrombectomy more often than in 2013–2014 (87 vs. 32%, respectively; p < 0.0001), with a significant improvement in clinical outcome (shift analysis, lower modified Rankin scale scores: OR = 1.68; 95% CI: 1.10–2.57; p = 0.017).Conclusion: Following the publication of RT, thrombectomy was rapidly implemented with significant improvements in intrahospital delay and reperfusion rates. Treatment with thrombectomy increased with better clinical outcomes in patients with M1 occlusion

Assessment of therapies targeting vasospasm management following aneurysmal subarachnoid hemorrhage

La médecine fondée sur des preuves s’est particulièrement imposée ces dernières décennies tout particulièrement dans les pays anglosaxons. Mais de nombreuses pratiques médicales courantes restent à ce jour non validées. Malgré une limitation croissante de ces pratiques, il existe dans certains domaines une grande liberté de pratique, pour le meilleur et pour le pire. L’exigence de preuve ne devrait-elle pas laisser place à l’exigence d’évaluation ? Ces considérations ont guidé ce travail de recherche sur l’angioplastie du vasospasme, thérapie non validée à ce jour mais réalisée en pratique courante dans de nombreux centres. Notre travail a consisté en premier lieu à faire une revue de la littérature sur le vasospasme, l’ischémie cérébrale retardée et l’angioplastie du vasospasme au décours des hémorragies sous arachnoïdiennes par rupture d’anévrysme. Nous avons participé également à la réalisation d’une méta-analyse sur le traitement de cette pathologie (Boulouis et al. 2016). Cette première étape a mis en évidence des contradictions dans les conclusions sur le lien entre le vasospasme et de l’ischémie cérébrale retardée pouvant être attribuées à des méthodologies biaisées ou utilisant des tests de faible sensibilité. Cette analyse a également permis d’affirmer qu’il n’existait à ce jour aucune preuve de l’efficacité du vasospasme. Nous avons cherché dans un second temps à redéterminer le lien entre l’ischémie cérébrale retardée et le vasospasme en utilisant une méthodologie plus robuste qu’employée jusqu’à présent (Brami et al. 2020 ; Simonato et al. Soumission 2021). Ce travail a permis de conforter l’association entre le vasospasme et l’ischémie cérébrale retardée. En outre, il a permis de mieux déterminer la topographie du vasospasme et de montrer de manière originale que le vasospasme épargne les vaisseaux entre 150 et 900 microns, et prédomine au niveau des segments moyens des artères cérébrales dans près de 40%. Enfin, nous avons cherché à définir quelque technique d’angioplastie était la plus efficace. Nous avons pour cela réalisé une comparaison de cohorte historique montrant une supériorité de la vasodilatation mécanique distale + IV par rapport à la vasodilatation mécanique proximale + IA en stratégie de première intention. Cette évaluation a également permis de souligner des limites importantes du processus de sélection des patients pour la vasodilatation dont bon nombre était traité trop tardivement. Nous avons également réalisé une comparaison inter centre de 2 stratégies opposées de traitement du vasospasme qui n’a pas permis de montrer de supériorité de la vasodilatation mécanique distale + IV par rapport à une attitude conservatrice sans vasodilatation. En conclusion, notre travail permet de définir les prochaines étapes de validation de l’angioplastie de vasospasme en suggérant notamment l’intérêt d’une randomisation explicative comparant la vasodilatation mécanique distale + traitement médical standard vs. traitement médical standard seul.Evidence-based medicine has gained importance in recent decades, particularly in Anglo-Saxon countries. But many common medical practices remain unvalidated to this day. In spite of an increasing limitation of these practices, there are some areas of practice with no recommendation, for better or for worse. Shouldn't the requirement for evidence to be the requirement for evaluation? These considerations guided this research on vasospasm angioplasty, a therapy that is not yet validated but is performed in routine practice in many centers. Our work consisted first of all of a review of the literature on vasospasm, delayed cerebral ischemia, and vasospasm angioplasty after subarachnoid hemorrhage due to aneurysm rupture. We also participated in the completion of a meta-analysis on the treatment of this condition (Boulouis et al. 2016). This first step highlighted contradictions in the findings on the association between vasospasm and delayed cerebral ischemia that could be attributed to biased methodologies or using tests with low sensitivity. This review also stated that there was no evidence to date for the efficacy of vasospasm. We sought in a second step to determine the link between delayed cerebral ischemia and vasospasm using a more robust methodology than employed to date (Brami et al. 2020; Simonato et al. Submission 2021). This work supported the association between vasospasm and delayed cerebral ischemia. In addition, it has allowed us to better determine the topography of vasospasm and to show in an original way that vasospasm spares vessels between 150 and 900 microns, and predominates at the level of the middle segments of cerebral arteries in almost 40%. Finally, we sought to define which angioplasty technique was the most effective. To this end, we performed a historical cohort comparison showing superiority of distal mechanical vasodilation + intravenous vasodilation (IV) over proximal mechanical vasodilation + intraarterial vasodilation as a first-line strategy. This evaluation also highlighted important limitations of the patient selection process for vasodilation, many of whom were treated too late. We also performed an inter-center comparison of 2 opposing vasospasm treatment strategies that did not show superiority of distal mechanical vasodilation + IV over a conservative attitude without vasodilation. In conclusion, our work helps define the next steps in the validation of vasospasm angioplasty by suggesting, in particular, the interest of an explanatory randomization comparing distal mechanical vasodilation + standard medical treatment vs. standard medical treatment alone