Balanced homodyne detection in second-harmonic generation microscopy

We demonstrate the association of two-photon nonlinear microscopy with balanced homodyne detection for investigating second harmonic radiation properties at nanoscale dimensions. Variation of the relative phase between second-harmonic and fundamental beams is retrieved, as a function of the absolute orientation of the nonlinear emitters. Sensitivity down to approximately 3.2 photon/s in the spatio-temporal mode of the local oscillator is obtained. This value is high enough to efficiently detect the coherent second-harmonic emission from a single KTiOPO4 crystal of sub-wavelength size.Comment: 9 pages to appear in Applied Physics Letter

Endommagement d'une structure composite soumise à un chargement mécanique élevé, constant et de longue durée (S06).

Un des modes de ruine des matériaux composites est la microfissuration de la matrice, qui peut être modélisée dans le cadre de la mécanique de l'endommagement. L'endommagement évolue sous des chargements monotones ou bien cyclés. L'objectif est d'étudier, dans le cadre de chargements élevés, constants et de longues durées, l'évolution de cet endommagement, et plus particulièrement les modalités de propagation de fissures transverses, de stratifiés carbone/époxy. Une première campagne d'essais de traction a été réalisée sur des éprouvettes stratifiées afin d'identifier les paramètres matériaux et de comprendre les différents processus d'endommagement. Des essais longs termes étant nécessaires pour caractériser les phénomènes de fluage et de relaxation, un banc d'essai a été réalisé

DAMAGE EVOLUTION UNDER LONG-TERM, HIGH AND CONSTANT LOADING OF A CARBON/EPOXY LAMINATE

International audienceWhen a composite material of carbon fiber and epoxy resin is subjected to mechanical loading, different phenomena can lead to changes in its properties or even irreversible damage (propagation of cracks, debonding between folds, fiber breakage). The objective of this work is to study, under high loads and long periods, the propagation of transverse microcracks (diffuse damage) until the fracture of the laminate under matrix modes (instability). Since long term tests are necessary to characterize the damage evolution as well as the creep and stress relaxation phenomena, a testing machine was carried out. Optimal orientations ([45°,-45°]ns and [60°,-60°]ns) and specimen shape have been defined to study this phenomena. Experimental results are presented here and it is observed an evolution of the matrix damage under constant loads. This evolution is compared to the evolution of the matrix damage in the case of cyclic loads (fatigue) which in this latter case is faster

Photostable Second-Harmonic Generation from a Single KTiOPO 4 Nanocrystal for Nonlinear Microscopy

International audienc

L’art du diorama (1700-2000)

Il y a vingt ans, Publics & Musées consacrait un numéro aux dioramas. Ce dispositif, qui s’est entre temps réactualisé sous diverses formes, notamment dans l’art contemporain, fait l’objet d’une nouvelle livraison, qui problématise leur puissance narrative, ainsi que la tentation hyperréaliste et l’instauration d’un rapport spécifique à la réalité et aux savoirs qui les caractérisent. Il s’agit de remettre le diorama au centre d’une étude des institutions muséales, de la production à la réception, avec un accent mis sur la matérialité de ces dispositifs et certaines de leur formes-limites. Twenty years ago, Publics & Musées dedicated an issue to dioramas. This device, which has since been updated in various forms, particularly in contemporary art, is the subject of a new contribution. This reappraisal problematizes characteristic aspects of the dioramas, such as their narrative power, their hyperrealistic lure, as well as their specific relationship to reality and knowledge. The aim is to refocus the diorama on a study of museum institutions, from production to reception, with an emphasis on their materiality and some of their extreme forms. Hace veinte años, la revista Publics & Musées, dedicaba un número a los dioramas. Este dispositivo, que mientras tanto se ha ido actualizando en varias formas, particularmente en el arte contemporáneo, es el tema de una nueva entrega, que problematiza su poder narrativo, así como la tentación hiperrealista y el establecimiento de una relación específica con la realidad y el conocimiento que le caracteriza. Se trata de situar al diorama en el centro de un estudio de las instituciones museísticas, desde la producción hasta la recepción, haciendo énfasis en la materialidad de estos dispositivos y algunas de sus formas límite

A phase II, single-arm, multicentre study of coltuximab ravtansine (SAR3419) and rituximab in patients with relapsed or refractory diffuse large B-cell lymphoma

International audienceIn this phase II, multicentre, single-arm study, 52 patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) received the anti-CD19 antibody–drug conjugate coltuximab ravtansine (55 mg/m2) and rituximab (375 mg/m2) weekly for 4 weeks, then every 2 weeks for 8 weeks. The primary endpoint was objective response rate (ORR) by International Working Group Criteria. The primary objective was to reject the null hypothesis of an ORR of ≤40%. Among 45 evaluable patients, the ORR was 31·1% (80% confidence interval [CI]: 22·0–41·6%) and the primary objective was not met. The ORR appeared higher in patients with relapsed disease (58·3% [80% CI: 36·2–78·1%]) versus those refractory to their last (42·9% [80% CI: 17·0–72·1%]) or first-line therapy (15·4% [80% CI: 6·9–28·4%]). Median progression-free survival, overall survival and duration of response were 3·9 [80% CI: 3·22–3·98], 9·0 [80% CI: 6·47–13·67] and 8·6 (range: 0–18) months, respectively. The pharmacokinetics of both drugs were unaffected by co-administration. Common adverse events included gastrointestinal disorders (52%) and asthenia (25%). No patients discontinued due to adverse events. In conclusion, coltuximab ravtansine with rituximab was well tolerated and yielded clinical responses in a subset of patients with relapsed/refractory DLBC

Rodent and nonrodent malaria parasites differ in their phospholipid metabolic pathways[S]

Malaria, a disease affecting humans and other animals, is caused by a protist of the genus Plasmodium. At the intraerythrocytic stage, the parasite synthesizes a high amount of phospholipids through a bewildering number of pathways. In the human Plasmodium falciparum species, a plant-like pathway that relies on serine decarboxylase and phosphoethanolamine N-methyltransferase activities diverts host serine to provide additional phosphatidylcholine and phosphatidylethanolamine to the parasite. This feature of parasitic dependence toward its host was investigated in other Plasmodium species. In silico analyses led to the identification of phosphoethanolamine N-methyltransferase gene orthologs in primate and bird parasite genomes. However, the gene was not detected in the rodent P. berghei, P. yoelii, and P. chabaudi species. Biochemical experiments with labeled choline, ethanolamine, and serine showed marked differences in biosynthetic pathways when comparing rodent P. berghei and P. vinckei, and human P. falciparum species. Notably, in both rodent parasites, ethanolamine and serine were not significantly incorporated into phosphatidylcholine, indicating the absence of phosphoethanolamine N-methyltransferase activity. To our knowledge, this is the first study to highlight a crucial difference in phospholipid metabolism between Plasmodium species. The findings should facilitate efforts to develop more rational approaches to identify and evaluate new targets for antimalarial therapy

Increased risk of severe COVID-19 in hospitalized patients with SARS-CoV-2 Alpha variant infection: a multicentre matched cohort study

International audienceBackground: The impact of the variant of concern (VOC) Alpha on the severity of COVID-19 has been debated. We report our analysis in France.Methods: We conducted an exposed/unexposed cohort study with retrospective data collection, comparing patients infected by VOC Alpha to contemporaneous patients infected by historical lineages. Participants were matched on age (± 2.5 years), sex and region of hospitalization. The primary endpoint was the proportion of hospitalized participants with severe COVID-19, defined as a WHO-scale > 5 or by the need of a non-rebreather mask, occurring up to day 29 after admission. We used a logistic regression model stratified on each matched pair and accounting for factors known to be associated with the severity of the disease.Results: We included 650 pairs of patients hospitalized between Jan 1, 2021, and Feb 28, 2021, in 47 hospitals. Median age was 70 years and 61.3% of participants were male. The proportion of participants with comorbidities was high in both groups (85.0% vs 90%, p = 0.004). Infection by VOC Alpha was associated with a higher odds of severe COVID-19 (41.7% vs 38.5%-aOR = 1.33 95% CI [1.03-1.72]).Conclusion: Infection by the VOC Alpha was associated with a higher odds of severe COVID-19