Exposure to Perflouroalkyl acids and foetal and maternal thyroid status: a review

Background Exposure to perfluorinated-alkyl-acids (PFAAs) is ubiquitous. PFAAs are hormone-disrupting compounds that are strongly suspected to affect mother-child-health such as fetal growth. Thyroid disruption is a plausible mechanism of action. We aim to summarize the epidemiological evidence for the relation between prenatal and postnatal exposure to PFAAs and disruption of thyroid homeostasis in mothers and/or infants. Method Fifteen original publications on PFAAs concentrations and thyroid hormones (TH) in pregnant women and/or infants were found upon a literature search in the PubMed database. Information on exposure to seven PFAAs congeners [Perfluorooctane sulfonate (PFOS), Perfluorooctanoate (PFOA), Perfluorohexane sulfonate (PFHxS), Perfluorononanoic acid (PFNA), Perfluorodecanoic acid (PFDA), Perfluoroundecanoic acid (PFUnA), and Perfluorododecanoic acid (PFDoA)] and thyroid stimulating hormone (TSH), free and total thyroxine (FT4 and TT4), free and total triiodothyronine (FT3 and TT3), T3RU (Free triiodothyronine resin uptake) and FT4-index (FT4I) levels were recorded. We evaluated sampling of maternal TH by trimester, and infant TH by sex stratification. Reported associations between mother or infant PFAAs and TH were not uniformly assessed in the selected studies. Results Ten out of the fifteen studies examined maternal PFAAs concentration and TSH level. Seven studies showed significant associations between TSH and exposure to six PFAAs congeners, most of them were positive. Maternal T4 and T3 were investigated in nine studies and five studies found inverse associations between exposure to six PFAAs congeners and TH (TT3, TT4, FT3, FT4 and FT4I) levels. Eight of the fifteen studies investigated PFAAs concentrations and infant TSH. Infant TSH level was significantly affected in four studies, positively in three studies. Nine studies investigated infant T4 and T3 and seven studies found significant associations with PFAAs exposure. However, both inverse and positive significant associations with infant TH were found eliciting no clear direction. Conclusion Results indicate a mainly positive relationship between maternal PFAAs concentrations and TSH levels, and suggestion of an inverse association with T4 and/or T3 levels. Associations of infant TH with PFAAs concentration were less consistent.Det Frie Forskningsrad (DFF) 30531European Unions' Horizon 2020 research and innovation Programme 733032 HBM4E

Robust estimate of dynamo thresholds in the von Kármán sodium experiment using the extreme value theory

International audienceWe apply a new threshold detection method based on the extreme value theory (EVT) to the von Kármán sodium (VKS) experiment data. The VKS experiment is a successful attempt to get a dynamo magnetic field in a laboratory liquidmetal experiment. We first show that the dynamo threshold is associated with a change of the probability density function of the extreme values of the magnetic field. This method does not require the measurement of response functions from applied external perturbations and thus provides a simple threshold estimate. We apply our method to different configurations in the VKS experiment, showing that it yields a robust indication of the dynamo threshold as well as evidence of hysteretic behaviors. Moreover, for the experimental configurations in which a dynamo transition is not observed, the method provides a way to extrapolate an interval of possible threshold values

Vélocimétrie dans les liquides conducteurs : sonde à distorsion magnétique

Nous proposons un nouveau type de sonde pour la mesure de vitesse dans les métaux liquides. Son principe repose sur la mesure du champ magnétique induit par un écoulement de fluide conducteur au voisinage d'un champ magnétique localisé. La méthode utilisée ici permet de mesurer à la fois la moyenne et les fluctuations. Celle-ci a été testé dans un écoulement laminaire et dans un écoulement turbulent de gallium liquide dit de Von Karman. Une excellente corrélation a été observé avec les signaux d'une sonde de potentiel prise comme référence

Brachytic2/ZmABCB1 functions in IAA export from intercalary meristems

Dwarfism traits in Zea mays are regulated by multiple factors including the hormone auxin. Dwarf brachytic2 (br2) mutants harbour lesions in the gene encoding an orthologue of Arabidopsis thaliana ABCB1 which functions in auxin efflux out of meristematic regions in the shoot and root. br2 mesocotyls and coleoptiles exhibit reduced auxin transport. However, the dwarf stature of br2 derives from shortened lower internodes whilst the upper portion of the plant is completely normal. As such, it is counter-intuitive to attribute br2 dwarfism exclusively to reduced auxin export out of the shoot apex. Arabidopsis abcb1 mutants exhibit only minor reductions in auxin transport and plant height unless combined with mutations in the ABCB19 auxin transporter. Phylogenetic modelling analysis excludes the possibility that BR2 is more closely related to ABCB19 which has three more closely related orthologues in maize. BR2 is expressed in nodal meristems, and analyses of auxin transport and content indicate that BR2 function in these grass-specific tissues is analogous to ABCB1 function in the shoot and root apex of Arabidopsis. These results indicate that ABCB1/BR2 function is conserved between dicots and monocots, but also suggests that this function must be understood in the context of the segmental organization of grass plants

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Etudes expérimentales de l'instabilité dynamo : mécanismes de génération et saturation

This PhD thesis deals with several problems relative to the dynamo instability in liquid metals turbulent flows. This instability converts kinetic energy into magnetic one in electrically conductive flows. It is the root of the magnetic field of the Earth and the Sun.We address the estimation of threshold of the instability, the influence of the flow configuration and of the electromagnetic boundary conditions as well as the saturation mechanism of the magnetic field. This experimental work rely on two turbulent flows of von Kármán type: in liquid sodium located in Cadarache (VKS collaboration) and in liquid gallium in ENS de Lyon.First we analyze several criteria about the estimation of the distance to threshold of the dynamo instability with the magnetic response of the system to a magnetic excitation for the self sustained dynamo in the VKS experiment. These method have been checked for dynamo configurations and then applied for non-dynamo configurations. Then, we study the influence of the flow on the dynamo field under the action of global hydrodynamic bifurcations. We describe a bistability of the flow which triggers two dynamo branches of different amplitude and the dynamics of the transitions between both hydrodynamic and magnetic states.We then focus on the saturation mechanism with the semi-synthetic Bullard-von Karman dynamo, involving a turbulent induction mechanism and an artificial electronic feedback. This setup allows to observe dynamo action for very low magnetic Reynolds number, far below the natural threshold of the instability.We observe an intermittent regime close to threshold and a fluid saturation by Lorentz force feedback on the flow. We specify the scaling laws and a power budget estimation of this regime. A sub-critical regime is also introduced and characterized.In the last section we detailed several measurement techniques in liquid metals developed and used during the PhD.Ce travail de thèse s’articule autour de plusieurs questions relatives à l’instabilité dynamo dans des écoulements turbulents en métaux liquides. Cette instabilité de conversion d’énergie cinétique en énergie magnétique dans les fluides électriquement conducteurs est à l’origine, par exemple, des champs magnétiques terrestre et solaire. En particulier, nous abordons l’estimation du seuil de l’instabilité, l’influence de l’écoulement et des conditions aux limites ainsi que les mécanismes de saturation du champ magnétique. Ces travaux expérimentaux s’appuient sur deux écoulements turbulents de type von Kármán : en sodium liquide à Cadarache (collaboration VKS) et en gallium liquide à l’ENS de Lyon.Dans un premier temps, l’étude est consacrée à l’analyse de critères permettant d’estimer la distance au seuil de l’instabilité dynamo, à travers la mesure de la réponse magnétique du système à une excitation pour la dynamo auto-entretenue VKS. Ces critères ont été validés dans les configurations dynamos de l’expérience puis appliquées aux configurations non-dynamo.Ensuite, nous illustrons l’influence de l’écoulement sur le champ dynamo à travers l’étude de bifurcations globales. Une bistabilité hydrodynamique, pilotant deux branches dynamos d’amplitude différentes, est décrite ainsi que les liens entre les états magnétiques et hydrodynamiques.Nous portons notre attention sur l’étude des mécanismes de saturation à travers la dynamo semi- synthétique de Bullard-von Karman mettant en jeu un mécanisme d’induction turbulente et un mécanisme de bouclage artificiel permettant l’observation d’une dynamo à faible nombre de Reynolds magnétique. L’instabilité démarre à travers un régime intermittent et sature par la rétroaction des forces de Lorentz sur l’écoulement. Nous donnons les lois d’échelle et le bilan de puissance de ce régime. Un régime d’instabilité sous-critique est aussi introduit et caractérisé.Nous détaillons dans une dernière partie, les techniques de mesure spécifiques aux métaux liquides utilisées et développées au cours de la thèse

Experimental studies of the dynamo instability : generation and saturation mechanisms

Ce travail de thèse s’articule autour de plusieurs questions relatives à l’instabilité dynamo dans des écoulements turbulents en métaux liquides. Cette instabilité de conversion d’énergie cinétique en énergie magnétique dans les fluides électriquement conducteurs est à l’origine, par exemple, des champs magnétiques terrestre et solaire. En particulier, nous abordons l’estimation du seuil de l’instabilité, l’influence de l’écoulement et des conditions aux limites ainsi que les mécanismes de saturation du champ magnétique. Ces travaux expérimentaux s’appuient sur deux écoulements turbulents de type von Kármán : en sodium liquide à Cadarache (collaboration VKS) et en gallium liquide à l’ENS de Lyon.Dans un premier temps, l’étude est consacrée à l’analyse de critères permettant d’estimer la distance au seuil de l’instabilité dynamo, à travers la mesure de la réponse magnétique du système à une excitation pour la dynamo auto-entretenue VKS. Ces critères ont été validés dans les configurations dynamos de l’expérience puis appliquées aux configurations non-dynamo.Ensuite, nous illustrons l’influence de l’écoulement sur le champ dynamo à travers l’étude de bifurcations globales. Une bistabilité hydrodynamique, pilotant deux branches dynamos d’amplitude différentes, est décrite ainsi que les liens entre les états magnétiques et hydrodynamiques.Nous portons notre attention sur l’étude des mécanismes de saturation à travers la dynamo semi- synthétique de Bullard-von Karman mettant en jeu un mécanisme d’induction turbulente et un mécanisme de bouclage artificiel permettant l’observation d’une dynamo à faible nombre de Reynolds magnétique. L’instabilité démarre à travers un régime intermittent et sature par la rétroaction des forces de Lorentz sur l’écoulement. Nous donnons les lois d’échelle et le bilan de puissance de ce régime. Un régime d’instabilité sous-critique est aussi introduit et caractérisé.Nous détaillons dans une dernière partie, les techniques de mesure spécifiques aux métaux liquides utilisées et développées au cours de la thèse.This PhD thesis deals with several problems relative to the dynamo instability in liquid metals turbulent flows. This instability converts kinetic energy into magnetic one in electrically conductive flows. It is the root of the magnetic field of the Earth and the Sun.We address the estimation of threshold of the instability, the influence of the flow configuration and of the electromagnetic boundary conditions as well as the saturation mechanism of the magnetic field. This experimental work rely on two turbulent flows of von Kármán type: in liquid sodium located in Cadarache (VKS collaboration) and in liquid gallium in ENS de Lyon.First we analyze several criteria about the estimation of the distance to threshold of the dynamo instability with the magnetic response of the system to a magnetic excitation for the self sustained dynamo in the VKS experiment. These method have been checked for dynamo configurations and then applied for non-dynamo configurations. Then, we study the influence of the flow on the dynamo field under the action of global hydrodynamic bifurcations. We describe a bistability of the flow which triggers two dynamo branches of different amplitude and the dynamics of the transitions between both hydrodynamic and magnetic states.We then focus on the saturation mechanism with the semi-synthetic Bullard-von Karman dynamo, involving a turbulent induction mechanism and an artificial electronic feedback. This setup allows to observe dynamo action for very low magnetic Reynolds number, far below the natural threshold of the instability.We observe an intermittent regime close to threshold and a fluid saturation by Lorentz force feedback on the flow. We specify the scaling laws and a power budget estimation of this regime. A sub-critical regime is also introduced and characterized.In the last section we detailed several measurement techniques in liquid metals developed and used during the PhD