Spitzer Follow-up of Extremely Cold Brown Dwarfs Discovered by the Backyard Worlds: Planet 9 Citizen Science Project

We present Spitzer follow-up imaging of 95 candidate extremely cold brown dwarfs discovered by the Backyard Worlds: Planet 9 citizen science project, which uses visually perceived motion in multi-epoch WISE images to identify previously unrecognized substellar neighbors to the Sun. We measure Spitzer [3.6]-[4.5] color to phototype our brown dwarf candidates, with an emphasis on pinpointing the coldest and closest Y dwarfs within our sample. The combination of WISE and Spitzer astrometry provides quantitative confirmation of the transverse motion of 75 of our discoveries. Nine of our motion-confirmed objects have best-fit linear motions larger than 1"/yr; our fastest-moving discovery is WISEA J155349.96+693355.2 (total motion ~2.15"/yr), a possible T type subdwarf. We also report a newly discovered wide-separation (~400 AU) T8 comoving companion to the white dwarf LSPM J0055+5948 (the fourth such system to be found), plus a candidate late T companion to the white dwarf LSR J0002+6357 at 5.5' projected separation (~8,700 AU if associated). Among our motion-confirmed targets, five have Spitzer colors most consistent with spectral type Y. Four of these five have exceptionally red Spitzer colors suggesting types of Y1 or later, adding considerably to the small sample of known objects in this especially valuable low-temperature regime. Our Y dwarf candidates begin bridging the gap between the bulk of the Y dwarf population and the coldest known brown dwarf.Comment: accepted for publication in The Astrophysical Journa

Mutagenèse conditionnelle dans le système sérotoninergique central de la souris par transfert viral de la recombinase Cre

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Probiotic and enterohemorrhagic Escherichia coli: An effective strategy against a deadly enemy?

Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens that constitute a serious public health threat. Currently, there is no specific treatment available for EHEC infections in human creating an urgent need for the development of alternative therapeutic strategies. Among them, one of the most promising approaches is the use of probiotic microorganisms. Even if many studies have shown the antagonistic effects of probiotic bacteria or yeast on EHEC survival, virulence, adhesion on intestinal epithelium or pathogen-induced inflammatory responses, mechanisms mediating their beneficial effects remain unclear. This review describes EHEC pathogenesis and novel therapeutic strategies, with a particular emphasis on probiotics. The interests and limits of a probiotic-based approach and the way it might be incorporated into global health strategies against EHEC infections will be discussed

<em>In vitro</em> adhesion properties of shiga toxin-producing <em>Escherichia coli</em> isolated from cattle, food, and humans

International audienceShiga toxin-producing Escherichia coli (STEC) are able to cause serious illnesses ranging from diarrhea to hemorrhagic colitis and hemolytic-uremic syndrome (HUS). These bacteria colonize the digestive tract of humans and produce Shiga-toxins, which are considered to be essential for virulence and are crucial in lethal infection. Colon colonization is supposed to be a determinant step in the development of the infection, but the virulence traits that mediate this step are unclear. We analyzed the ability of 256 STEC strains belonging to seropathotype A (the most virulent 0157:H7 serotype) to seropathotype E (not involved in human disease) to adhere to HEp-2, HCT-8, and T84 cell lines. Of the 256 STEC tested most (82%) were non-adherent in our assays. The adhesion levels were globally low and were not related to pathogenicity, although the highest levels were associated to 026:H11 and 0103:H2 strains of seropathotype B (associated with HUS but less commonly than serotype 0157:H7), possessing both the eae and toxB genes

Optimization of E-nose technology for detecting nonanal: a COVID-19 biomarker in exhaled breath

International audienceA low-cost, rapid and non-invasive diagnosis of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection is needed for the prevention and control of the pandemic. Coronavirus disease 2019 (COVID-19) mainly affects the respiratory tract and lungs. Therefore, analysis of exhaled breath could be an alternative scalable method for reliable SARS-CoV-2 screening. In this work, an experimental protocol using an electronic nose (“e-nose”) for identifying a specific respiratory imprint in COVID-19 patients was optimized. The analytical performances of the Cyranose ® , a commercial e-nose device, were characterized by using a gas rig. In addition, the effect of various experimental conditions on its sensor array response was assessed, including relative humidity, sampling time and flow rate, aiming to select the optimal parameters. We also evaluated whether the Cyranose ® could distinguish between expired air from five healthy patients spiked or not with nonanal, identified as one putative COVID-19 biomarker. Electrical resistance variation of 32 sensors was recorded in real-time by using the PC-nose software during all tests. A statistical data analysis was applied to e-nose sensor response using a software called “Enair” developed on purpose and using a built-in optimized algorithm.Cyranose® reveals a possible detection of low concentrations of nonanal (5 ppb) in breath and a significant discrimination from others Volatile Organic Compounds (VOCs) of healthy patients

Assessment of an e-nose performance for the detection of COVID-19 specific biomarkers

International audienceEarly, rapid and non-invasive diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is needed for the prevention and control of coronavirus disease 2019 (COVID-19). COVID-19 mainly affects the respiratory tract and lungs. Therefore, analysis of exhaled breath could be an alternative scalable method for reliable SARS-CoV-2 screening. In the current study, an experimental protocol using an electronic-nose (‘e-nose’) for attempting to identify a specific respiratory imprint in COVID-19 patients was optimized. Thus the analytical performances of the Cyranose ® , a commercial e-nose device, were characterized under various controlled conditions. In addition, the effect of various experimental conditions on its sensor array response was assessed, including relative humidity, sampling time and flow rate, aiming to select the optimal parameters. A statistical data analysis was applied to e-nose sensor response using common statistical analysis algorithms in an attempt to demonstrate the possibility to detect the presence of low concentrations of spiked acetone and nonanal in the breath samples of a healthy volunteer. Cyranose ® reveals a possible detection of low concentrations of these two compounds, in particular of 25 ppm nonanal, a possible marker of SARS-CoV-2 in the breath

Optimization of E-nose technology for detecting nonanal: a COVID-19 biomarker in exhaled breath

International audienceA low-cost, rapid and non-invasive diagnosis of Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) infection is needed for the prevention and control of the pandemic. Coronavirus disease 2019 (COVID-19) mainly affects the respiratory tract and lungs. Therefore, analysis of exhaled breath could be an alternative scalable method for reliable SARS-CoV-2 screening. In this work, an experimental protocol using an electronic nose (“e-nose”) for identifying a specific respiratory imprint in COVID-19 patients was optimized. The analytical performances of the Cyranose ® , a commercial e-nose device, were characterized by using a gas rig. In addition, the effect of various experimental conditions on its sensor array response was assessed, including relative humidity, sampling time and flow rate, aiming to select the optimal parameters. We also evaluated whether the Cyranose ® could distinguish between expired air from five healthy patients spiked or not with nonanal, identified as one putative COVID-19 biomarker. Electrical resistance variation of 32 sensors was recorded in real-time by using the PC-nose software during all tests. A statistical data analysis was applied to e-nose sensor response using a software called “Enair” developed on purpose and using a built-in optimized algorithm.Cyranose® reveals a possible detection of low concentrations of nonanal (5 ppb) in breath and a significant discrimination from others Volatile Organic Compounds (VOCs) of healthy patients

Enterohemorrhagic Escherichia coli O157:H7 survival in an in vitro model of the human large intestine and interactions with probiotic yeasts and resident microbiota

International audienceThis is the first report on the fate of enterohemorrhagic Escherichia coli O157:H7 in simulated human colonic conditions. The pathogen was progressively eliminated from the bioreactor and did not modify the major populations of resident microbiota. The coadministration of the Saccharomyces cerevisiae CNCM I-3856 probiotic strain led to a significant increase in acetate production but did not reduce pathogen viability

Pre-conceptional maternal metabolic status influences hepatic metabolome in male offspring

Sofiane Safi-Stibler a obtenu une bourse de voyage de la Société Française de Nutrition pour présenter ses travaux lors de ce congrès. Sofiane Safi-Stibler a obtenu un prix de présentation orale lors du congrès de la SF-DOHaD à Grenoble en 2018 afin de présenter ses travaux au cours du Congrès International de la DOHaD 2019 à Melbourne.International audienceBackground/AimsMaternal obesity is associated with fertility disorders, obstetric complications, and development of metabolic syndrome in offspring. The recommendation to overweight or obese women is to lose weight before pregnancy, but the impact of these prescriptions on the offspring health is insufficiently studied. Previous results on late-term mice fetuses have shown that maternal obesity leads to fetal growth restriction and to the modification of epigenetic machinery-related gene expression in fetal liver and placenta. Moreover, fetuses from the preconceptional weight loss maternal group normalize their growth, but some fetal genes stay differentially expressed.MethodWe analysed the metabolic phenotype of offspring born to control (CTRL), obese (OB) or weight loss after diet-induced obesity (WL) mothers. To highlight a possible conditioning effect, offspring were either fed a control (CD) or a high fat diet (HFD). Their metabolism and olfactory behavior were monitored for up to 6 months. Then, we analyzed the metabolome of three tissues involved in food intake and nutrient management (liver, olfactory bulb and hypothalamus) in male adult offspring.ResultsMultiple Factorial Analysis integration of offspring phenotypic data showed a major influence of the post-weaning diet and pointed a difference in HFD-fed males according to their maternal group (OB vs WL). This confirmed a sex-dependant metabolic conditioning by the maternal environment. The olfactory sensitivity, measured by electro-olfactogram, was reduced in WL male offspring, whatever the postnatal diet.The metabolomics study annotated 278, 258 and 200 metabolites in the liver, olfactory bulb and hypothalamus respectively. Again, the post-weaning diet had a major effect in the three tissues but interestingly, the maternal group also influenced the hepatic metabolome of adult offspring.ConclusionsThese data, integrating metabolism, olfactory behavior and metabolome, provide new and original information on the effects of preconceptional maternal metabolic status in the offspring health conditioning upon diet challenges

Attractivité des carrières scientifiques et technologiques.: Identification des freins et proposition de leviers d'action

L'étude menée à l'initiative du Haut Conseil de la Science et de la Technologie sur l'attractivité des carrières scientifiques et technologiques a permis une approche globale de cette question. Les facteurs susceptibles d'avoir un impact significatif sur cette attractivité ont pu être identifiés, analysés et regroupés dans sept champs d'action qui sont plus ou moins liés les uns aux autres : 1) acquisition des compétences et système éducatif 2) connaissance des métiers et orientation 3) caractéristiques de l'emploi scientifique et technologique 4) perspectives de mobilité des acteurs de la recherche 5) perceptions et représentations sociales des sciences et des technologies 6) pratiques de médiation scientifique et technologique 7) pilotage et suivi des mesures en faveur de l'attractivité des carrières scientifiques et technologiques