Reorientation dynamics in thin glassy films

We present a study of orientational relaxation dynamics in thin films of a low-molecular-weight glass-former as a function of temperature and film thickness. The relaxation is probed by second-harmonic generation after release of a poling electric field. From the measured decays of the second-harmonic signal and their fitting with a stretched exponential, we can determine the distribution of relaxation times in the system. As temperature decreases from above the glass transition, we observe that the width of the distribution first increases under confinement, but that deeper in the glassy state, confinement has no effect anymore on the dynamics.Comment: 10 pages, including 12 figures, RevTeX

Teaching Real-Time Scheduling Analysis with Cheddar

National audienceThis article is a presentation of the Cheddar toolset.Cheddar is a GPL open-source scheduling analysis tool.It has been designed and distributed to allow students to understand the main concepts of the real-time scheduling theory.The tool is built around a simplified ADL (Architecture Description Language)devoted to real-time scheduling theory. Students can directly build their real-time systems models with this ADL andits associated editor, however, it is expected that they use modeling tools to illustrate how scheduling analysis fits in an engineering process.In this article, we introduce the Cheddar ADL and the scheduling analysis features of Cheddar. We alsopresent how Cheddar is implemented and how it can be adapted to specific requirements.Two examples of use of Cheddar are then described.Finally, in the annex of this article, teachers may find a sample of hand-outs that may be used to illustrate real-time scheduling theory with their students

Synthesis and anticancer activity evaluation of some new 1,2,3,5-tetrazine derivatives attached to benzothiazole moiety

A series of novel tetrazine derivatives, containing benzothiazole framework, were prepared during the coupling reactions of some diazotized 2-aminobenzo[d]thiazole derivatives with p-acetaminophen. Their structures were elucidated based on NMR and MS spectrometry. The anticancer activity and the safety of the synthesized compounds along with the entire precursors were assessed against three human cancer cell lines and a normal cell line. All the synthesized compounds showed selective cytotoxic activity against the cancer cell lines used in comparison to the normal Vero cell line. Their IC50 values varied from 2.02 to 171.67 μM.The Cameroonian Ministry of Higher Education special research allocation, the German Academic Exchange Service (DAAD) and the University of Pretoria.https://www.arkat-usa.org/arkivoc-journalam2023Paraclinical Science

Long-term cellular immunity of vaccines for Zaire Ebola Virus Diseases

Recent Ebola outbreaks underscore the importance of continuous prevention and disease control efforts. Authorized vaccines include Merck’s Ervebo (rVSV-ZEBOV) and Johnson & Johnson’s two-dose combination (Ad26.ZEBOV/MVA-BN-Filo). Here, in a five-year follow-up of the PREVAC randomized trial (NCT02876328), we report the results of the immunology ancillary study of the trial. The primary endpoint is to evaluate long-term memory T-cell responses induced by three vaccine regimens: Ad26–MVA, rVSV, and rVSV–booster. Polyfunctional EBOV-specific CD4+ T-cell responses increase after Ad26 priming and are further boosted by MVA, whereas minimal responses are observed in the rVSV groups, declining after one year. In-vitro expansion for eight days show sustained EBOV-specific T-cell responses for up to 60 months post-prime vaccination with both Ad26-MVA and rVSV, with no decline. Cytokine production analysis identify shared biomarkers between the Ad26-MVA and rVSV groups. In secondary endpoint, we observed an elevation of pro-inflammatory cytokines at Day 7 in the rVSV group. Finally, we establish a correlation between EBOV-specific T-cell responses and anti-EBOV IgG responses. Our findings can guide booster vaccination recommendations and help identify populations likely to benefit from revaccination

Action d'un champ electrique et des surfaces solides sur les cristaux liquides nematiques et les phases bleues

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Guide de prélèvements des otolithes chez les grands pélagiques

Ce guide présente les modes et règles de prélèvement puis de stockage des otolithes de grands pélagiques (thons et espadons). Ils ont été mis en place dans le cadre de projets de recherche comme « Germon » (http://wwz.ifremer.fr/lareunion/Les-projets/GERMON-en-cours), « IOSSS-Espadon » (http://wwz.ifremer.fr/lareunion/Les-projets/IOSSS-ESPADON) et «thon rouge (ICCAT-GBYP) » et dans le cadre de réseaux de surveillance coordonnés au niveau international, en particulier au sein du règlement européen sur la collecte des données halieutiques (DCMAP, Data Collection Multi Annual Programme). Ce guide a pour but de standardiser les prélèvements d’otolithes effectués à l'Ifremer sur ces grands pélagiques. Il reprend et complète la synthèse française des procédures d'estimation d'âge (Mahé et al., 2009), le manuel d'utilisation du fichier : "Parametres biologiques v7.xls" (Mahé et al., 2007) et le guide de prélèvement des pièces calcifiées (Mahé et al., 2013)

Using universal target design in conjunction with accuracy and multiwavelength knobs for non-critical layer ov measurements on YS-S375

International audienceContinued tightening of overlay control budget in semiconductor lithography drives the need for improved metrology capabilities. Aggressive improvements are needed for overlay metrology, accuracy and precision to address below 5nm on product overlay spec. However at the same time cost reduction driving factor leads to need of target reduction size as well as quick time to design target without performance loss on the YieldStar (YS) metrology tools.This paper will present metrology results of a scatterometry based platform showing metrology results with focus not only on precision and accuracy but also validate a target in a faster cycle time, in particular designs that could be used straight away on non-critical layers.Designed targets are validated with HMQ (Holistic Metrology Qualification) on product measurements techniques to deliver an optimized accurate recipe to the production line. The main takeaway from this paper is to use universal designs together with accuracy package-options using multiwavelength approach on YS-S375 to deliver best target performance

Die-Level nano-topography Metrology to characterize the stress-induced In-Plane Distortion contribution to overlay

International audienceIn the field of semiconductor manufacturing, the precise alignment of patterns on a wafer die is critical for the proper functioning of the resulting integrated circuit. However, various factors can cause deformation of the die, which can result in overlay errors and negatively impact device performance. In this work, we focused on the development of die nanotopography metrology, which is used to investigate the topography evolution of five selected dies over several process steps. The impact of manufacturing steps as film deposition, annealing and CMP on die shape deformation and its relation to different pattern densities is measured using optical interferometry. We show that full-die nano-topography measurements are able to detect stress-induced in-plane die distortions as an effect of different annealing processes on SOI or silicon-bulk substrates

In search of stress odours across species: behavioural responses of rats to faeces from chickens and rats subjected to various types of stressful events

International audienceStressed animals have an increased risk of health and welfare problems, thus methods for easy and early stress detection is important for appropriate animal management. Using the ability of rats to distinguish between faeces odours from stressed and non-stressed conspecifics, we investigated whether rats could detect stress status in another species (the chicken), which would suggest a commonality in odorous stress signatures across species. We carried out four experiments to investigate the existence of stress-specific odours. In the first experiment using a T-maze, male Brown Norway (BN) rats (n = 12) were found to sniff the faeces samples from stressed rats and chickens less relative to the samples from non-stressed individuals (P < 0.05). In the second experiment, where odours were presented in an arena one at a time, male BN rats (n = 16) sniffed faeces samples from stressed rats and chickens for longer than those from non-stressed controls (P< 0.05). Within each test, the same responses to stress odours were seen independent of species of origin. This suggests that both in rats and chickens stress gives rise to specific volatile organic compounds (VOCs). In a third experiment, faeces from chickens, which had been stressed or non-stressed at hatching and subsequently exposed or not to acute stress at two weeks of age were tested on male BN rats (n = 18). These rats were also tested with faeces from non-stressed and acutely stressed rats as well as herb odour (1-hexanol) used as control. Number of freezing episodes was higher when rats were exposed to any of the samples originating from stressed individuals compared to that observed with herb odour (P < 0.05). Also, defensive burying was more likely to occur when rats were exposed to faeces from chickens stressed at hatching (P < 0.05). Finally, a fourth trial analysed faecal samples from non-stressed and acutely stressed rats using gas chromatography coupled with mass spectrometry (GC-MS), and identified ten VOCs potentially involved in the distinctive smell detectable in faeces from acutely stressed rats. These findings confirm the existence of stress-specific odours in rats and indicate that, although not necessarily identical, a similar type of odour may be present in stressed poultry. In addition, this odour could be detected by rats in chicken faeces collected almost two weeks after the birds had been exposed to a stressful event. Our results suggest that patterns of VOCs may have the potential to be used as a tool for early, non-invasive screening of stress status in animals

Effects of extraction method and storage of dry tissue on marine lipids and fatty acids

Various protocols are currently used to study marine lipids, but there is a growing interest in working on dry samples that are easier to transport. However, reference protocols are still lacking for dry samples. In order to make recommendations on this use, lipid classes and fatty acids (FA) obtained from six analytical protocols using two different tissue states (dry vs wet) and three extraction methods (automat vs manual potter vs leaving the solvent to work on tissue) were compared. Three dry storage modes of tissue (freezer vs gas nitrogen vs dry room) during one and three months were also compared. These comparisons were made on seven marine species with different lipid profiles, including fishes, crustaceans and mollusks. Lipid classes and FA obtained from wet and dry tissues were similar, but they were affected by the extraction methods. Regardless of tissue state, “Leave to work” methods obtained the highest lipid quantities, followed by manual potter and automat methods (ca. 90% and 80% of “Leave to work” methods, respectively). Linear relationships allowed correction for lipid classes and FA concentrations obtained from different protocols. The repeatability of all protocols still needs to be improved, especially for fish species. Increasing the replicate number for each sample might be an indirect way to improve lipid quantification. Our results show that storing dry tissues in the freezer for more than one month was associated with a decrease in lipids, which is also observed for other storage methods. For qualitative studies of FA (expressed in %), a three-month storage of dry tissue in freezer did not affect the relative composition of species/tissues with a lipid content below 20% of dry weight