53 research outputs found
A European aerosol phenomenology - 7 : High-time resolution chemical characteristics of submicron particulate matter across Europe
Similarities and differences in the submicron atmospheric aerosol chemical composition are analyzed from a unique set of measurements performed at 21 sites across Europe for at least one year. These sites are located between 35 and 62 degrees N and 10 degrees W - 26 degrees E, and represent various types of settings (remote, coastal, rural, industrial, urban). Measurements were all carried out on-line with a 30-min time resolution using mass spectroscopy based instruments known as Aerosol Chemical Speciation Monitors (ACSM) and Aerosol Mass Spectrometers (AMS) and following common measurement guidelines. Data regarding organics, sulfate, nitrate and ammonium concentrations, as well as the sum of them called non-refractory submicron aerosol mass concentration ([NR-PM1]) are discussed. NR-PM1 concentrations generally increase from remote to urban sites. They are mostly larger in the mid-latitude band than in southern and northern Europe. On average, organics account for the major part (36-64%) of NR-PM1 followed by sulfate (12-44%) and nitrate (6-35%). The annual mean chemical composition of NR-PM1 at rural (or regional background) sites and urban background sites are very similar. Considering rural and regional background sites only, nitrate contribution is higher and sulfate contribution is lower in midlatitude Europe compared to northern and southern Europe. Large seasonal variations in concentrations (mu g/m(3)) of one or more components of NR-PM1 can be observed at all sites, as well as in the chemical composition of NR-PM1 (%) at most sites. Significant diel cycles in the contribution to [NR-PM1] of organics, sulfate, and nitrate can be observed at a majority of sites both in winter and summer. Early morning minima in organics in concomitance with maxima in nitrate are common features at regional and urban background sites. Daily variations are much smaller at a number of coastal and rural sites. Looking at NR-PM1 chemical composition as a function of NR-PM1 mass concentration reveals that although organics account for the major fraction of NR-PM1 at all concentration levels at most sites, nitrate contribution generally increases with NR-PM1 mass concentration and predominates when NR-PM1 mass concentrations exceed 40 mu g/m(3) at half of the sites.Peer reviewe
Data Descriptor : Collocated observations of cloud condensation nuclei, particle size distributions, and chemical composition
Cloud condensation nuclei (CCN) number concentrations alongside with submicrometer particle number size distributions and particle chemical composition have been measured at atmospheric observatories of the Aerosols, Clouds, and Trace gases Research InfraStructure (ACTRIS) as well as other international sites over multiple years. Here, harmonized data records from 11 observatories are summarized, spanning 98,677 instrument hours for CCN data, 157,880 for particle number size distributions, and 70,817 for chemical composition data. The observatories represent nine different environments, e.g., Arctic, Atlantic, Pacific and Mediterranean maritime, boreal forest, or high alpine atmospheric conditions. This is a unique collection of aerosol particle properties most relevant for studying aerosol-cloud interactions which constitute the largest uncertainty in anthropogenic radiative forcing of the climate. The dataset is appropriate for comprehensive aerosol characterization (e.g., closure studies of CCN), model-measurement intercomparison and satellite retrieval method evaluation, among others. Data have been acquired and processed following international recommendations for quality assurance and have undergone multiple stages of quality assessment.Peer reviewe
Copernicus Ocean State Report, issue 6
The 6th issue of the Copernicus OSR incorporates a large range of topics for the blue, white and green ocean for all European regional seas, and the global ocean over 1993â2020 with a special focus on 2020
Human Female Germ Line Development
La mise en place de la lignĂ©e germinale au cours du dĂ©veloppement constitue une des Ă©tapes fondamentales conditionnant la fertilitĂ© de lâindividu adulte. Au cours des derniĂšres dĂ©cennies, le nombre croissant de couples consultant pour une aide mĂ©dicale Ă la procrĂ©ation a fait Ă©merger lâhypothĂšse dâune altĂ©ration des fonctions de reproduction chez lâHomme qui pourrait trouver son origine dans la perturbation du dĂ©veloppement prĂ©coce. Dans lâovaire fĆtal, les cellules germinales sâorienteront vers la voie de lâovogĂ©nĂšse, caractĂ©risĂ©e entre autres par lâentrĂ©e en mĂ©iose de ces cellules. La majoritĂ© des donnĂ©es actuelles relatives Ă ces Ă©vĂšnements sont issues du modĂšle murin alors que le dĂ©veloppement de lâovaire humain est significativement diffĂšrent de celui de la souris. Il est donc nĂ©cessaire dâapprofondir nos connaissances du dĂ©veloppement ovarien humain et dâidentifier ses Ă©ventuelles perturbations. Lâobjectif de mon travail a Ă©tĂ© de mettre au point un outil dâĂ©tude du dĂ©veloppement ovarien et dâidentifier de nouvelles voies impliquĂ©es dans la rĂ©gulation de lâentrĂ©e en mĂ©iose des cellules germinales fĆtales humaines et leurs perturbations Ă©ventuelles.Nous avons mis au point un nouveau modĂšle de xĂ©nogreffe dâovaires fĆtaux humains du premier trimestre de gestation (au moment de lâapparition des premiĂšres cellules mĂ©iotiques). Ce modĂšle nous a permis dâobserver un dĂ©veloppement de lâorgane et une diffĂ©renciation des cellules germinales similaires Ă ceux observĂ©s in vivo. Ce modĂšle permettra des travaux Ă des Ăąges auxquels le matĂ©riel dâĂ©tude est peu accessible. En couplant ce modĂšle de xĂ©nogreffe Ă une stratĂ©gie dâARN-interfĂ©rence, il nous a Ă©tĂ© possible dâinhiber lâexpression dâun gĂšne spĂ©cifiquement exprimĂ© dans les cellules germinales ovariennes, DMRTA2, et de mettre en Ă©vidence un potentiel rĂŽle de ce gĂšne dans leur diffĂ©renciation prĂ©-mĂ©iotique. Nous avons observĂ© une diminution du nombre de cellules ayant initiĂ© la mĂ©iose aprĂšs inhibition de lâexpression de ce gĂšne. Par ailleurs, nous avons Ă©galement identifiĂ© la prĂ©sence dans lâovaire fĆtal de nombreux marqueurs dĂ©crits comme testiculaires chez la souris (PLZF, DNMT3L, FGF9, NANOS2 ou CYP26B1). Lâexpression de ces marqueurs pourrait expliquer la prĂ©sence de cellules mitotiques tardives dans lâovaire fĆtal humain que nous avons pu observer jusquâĂ 30 semaines de gestation. En parallĂšle de ces travaux, nous avons testĂ© la sensibilitĂ© des cellules germinales Ă la dexamĂ©thasone, glucocorticoĂŻde pouvant ĂȘtre administrĂ© au cours de la grossesse. Il a Ă©tĂ© observĂ© une augmentation de lâexpression de PLZF, gĂšne cible de lâactivation des rĂ©cepteurs aux glucocorticoĂŻdes, pouvant expliquer la diminution du nombre de cellules germinales.En conclusion, ce travail de thĂšse a permis dâidentifier un nouveau gĂšne potentiellement rĂ©gulateur de la transition mitose/mĂ©iose dans lâovaire humain, et dâaffiner nos connaissances sur le dĂ©veloppement de lâovaire humain et lâentrĂ©e en mĂ©iose des cellules germinales. Toutefois, de nombreuses questions restent posĂ©es ainsi de futures Ă©tudes devront clarifier si les cellules germinales mitotiques observĂ©es Ă des stades tardifs sont capables de se diffĂ©rencier en ovocytes compĂ©tents.Woman fertility is partially dictated by the set up of the human female germ line. During the last ten years, which saw an increased number of couples consulting for assisted reproductive cares, the hypothesis of an early alteration in reproduction functions has emerged.In the fetal ovary, germ cells enter the path of oogenesis differentiation characterized by meiotic initiation. On this subject, vast majority of the scientific data are obtained from the mouse model, even if differences with human ovarian physiology are widely acknowledged. Therefore it is necessary to extend our knowledge on human ovarian development and identify its perturbations. The objective of my work was to assess a new model to study ovarian growth, studying regulation of meiotic entry and perturbation of germ line differentiation.We sat up a new xenograft model of early human fetal ovaries, when very early meiotic germ cells appear. Organ growth and germ cells differentiation were comparable with in vivo observations. Using this model with an RNA-interference strategy, we inhibited the expression of an oogonia germ cell gene, DMRTA2. This inhibition conducted to a significantly reduced number of germ cells gene that initiated meiosis and DMRTA2 seemed to be required for mitotic-meiotic transition. In another hand, we identified, in the ovary, the expression of germ cells markers described as specifically male in rodent (PLZF, DNMT3L, FGF9, NANOS2 ou CYP26B1). The expression of these markers in the human ovary could explain the observation of mitotic germ cells in late fetal ovaries (30 wpf).In parallel, we tested germ cells sensibility to a synthetic glucocorticoid, dexamethasone, administrated during pregnancy in some justified pathologies. We observed an increased expression of PLZF that could explain the decreased number of germ cells observed in treated ovaries.In conclusion, we identified a new gene expressed in human fetal ovaries, potentially involved in the meiotic entry, and we extended our knowledge to characterized human germ line development. However, many points have to be clarified, as the possible competence of late mitotic germ cells to form oocytes
Développement de la lignée germinale femelle humaine
Woman fertility is partially dictated by the set up of the human female germ line. During the last ten years, which saw an increased number of couples consulting for assisted reproductive cares, the hypothesis of an early alteration in reproduction functions has emerged.In the fetal ovary, germ cells enter the path of oogenesis differentiation characterized by meiotic initiation. On this subject, vast majority of the scientific data are obtained from the mouse model, even if differences with human ovarian physiology are widely acknowledged. Therefore it is necessary to extend our knowledge on human ovarian development and identify its perturbations. The objective of my work was to assess a new model to study ovarian growth, studying regulation of meiotic entry and perturbation of germ line differentiation.We sat up a new xenograft model of early human fetal ovaries, when very early meiotic germ cells appear. Organ growth and germ cells differentiation were comparable with in vivo observations. Using this model with an RNA-interference strategy, we inhibited the expression of an oogonia germ cell gene, DMRTA2. This inhibition conducted to a significantly reduced number of germ cells gene that initiated meiosis and DMRTA2 seemed to be required for mitotic-meiotic transition. In another hand, we identified, in the ovary, the expression of germ cells markers described as specifically male in rodent (PLZF, DNMT3L, FGF9, NANOS2 ou CYP26B1). The expression of these markers in the human ovary could explain the observation of mitotic germ cells in late fetal ovaries (30 wpf).In parallel, we tested germ cells sensibility to a synthetic glucocorticoid, dexamethasone, administrated during pregnancy in some justified pathologies. We observed an increased expression of PLZF that could explain the decreased number of germ cells observed in treated ovaries.In conclusion, we identified a new gene expressed in human fetal ovaries, potentially involved in the meiotic entry, and we extended our knowledge to characterized human germ line development. However, many points have to be clarified, as the possible competence of late mitotic germ cells to form oocytes.La mise en place de la lignĂ©e germinale au cours du dĂ©veloppement constitue une des Ă©tapes fondamentales conditionnant la fertilitĂ© de lâindividu adulte. Au cours des derniĂšres dĂ©cennies, le nombre croissant de couples consultant pour une aide mĂ©dicale Ă la procrĂ©ation a fait Ă©merger lâhypothĂšse dâune altĂ©ration des fonctions de reproduction chez lâHomme qui pourrait trouver son origine dans la perturbation du dĂ©veloppement prĂ©coce. Dans lâovaire fĆtal, les cellules germinales sâorienteront vers la voie de lâovogĂ©nĂšse, caractĂ©risĂ©e entre autres par lâentrĂ©e en mĂ©iose de ces cellules. La majoritĂ© des donnĂ©es actuelles relatives Ă ces Ă©vĂšnements sont issues du modĂšle murin alors que le dĂ©veloppement de lâovaire humain est significativement diffĂšrent de celui de la souris. Il est donc nĂ©cessaire dâapprofondir nos connaissances du dĂ©veloppement ovarien humain et dâidentifier ses Ă©ventuelles perturbations. Lâobjectif de mon travail a Ă©tĂ© de mettre au point un outil dâĂ©tude du dĂ©veloppement ovarien et dâidentifier de nouvelles voies impliquĂ©es dans la rĂ©gulation de lâentrĂ©e en mĂ©iose des cellules germinales fĆtales humaines et leurs perturbations Ă©ventuelles.Nous avons mis au point un nouveau modĂšle de xĂ©nogreffe dâovaires fĆtaux humains du premier trimestre de gestation (au moment de lâapparition des premiĂšres cellules mĂ©iotiques). Ce modĂšle nous a permis dâobserver un dĂ©veloppement de lâorgane et une diffĂ©renciation des cellules germinales similaires Ă ceux observĂ©s in vivo. Ce modĂšle permettra des travaux Ă des Ăąges auxquels le matĂ©riel dâĂ©tude est peu accessible. En couplant ce modĂšle de xĂ©nogreffe Ă une stratĂ©gie dâARN-interfĂ©rence, il nous a Ă©tĂ© possible dâinhiber lâexpression dâun gĂšne spĂ©cifiquement exprimĂ© dans les cellules germinales ovariennes, DMRTA2, et de mettre en Ă©vidence un potentiel rĂŽle de ce gĂšne dans leur diffĂ©renciation prĂ©-mĂ©iotique. Nous avons observĂ© une diminution du nombre de cellules ayant initiĂ© la mĂ©iose aprĂšs inhibition de lâexpression de ce gĂšne. Par ailleurs, nous avons Ă©galement identifiĂ© la prĂ©sence dans lâovaire fĆtal de nombreux marqueurs dĂ©crits comme testiculaires chez la souris (PLZF, DNMT3L, FGF9, NANOS2 ou CYP26B1). Lâexpression de ces marqueurs pourrait expliquer la prĂ©sence de cellules mitotiques tardives dans lâovaire fĆtal humain que nous avons pu observer jusquâĂ 30 semaines de gestation. En parallĂšle de ces travaux, nous avons testĂ© la sensibilitĂ© des cellules germinales Ă la dexamĂ©thasone, glucocorticoĂŻde pouvant ĂȘtre administrĂ© au cours de la grossesse. Il a Ă©tĂ© observĂ© une augmentation de lâexpression de PLZF, gĂšne cible de lâactivation des rĂ©cepteurs aux glucocorticoĂŻdes, pouvant expliquer la diminution du nombre de cellules germinales.En conclusion, ce travail de thĂšse a permis dâidentifier un nouveau gĂšne potentiellement rĂ©gulateur de la transition mitose/mĂ©iose dans lâovaire humain, et dâaffiner nos connaissances sur le dĂ©veloppement de lâovaire humain et lâentrĂ©e en mĂ©iose des cellules germinales. Toutefois, de nombreuses questions restent posĂ©es ainsi de futures Ă©tudes devront clarifier si les cellules germinales mitotiques observĂ©es Ă des stades tardifs sont capables de se diffĂ©rencier en ovocytes compĂ©tents
Potentiel évolutif des embryons de bas grade non congelables au troisiÚme jour de développement
MONTPELLIER-BU Pharmacie (341722105) / SudocSudocFranceF
Epigenetic alterations of the first trimester placenta: insight into preoccupying concerns in assisted reproductive technology
International audienc
How Recent Advances in Biology of Waldenström's Macroglobulinemia May Affect Therapy Strategy
International audiencePurpose of Review: Waldenström macroglobulinemia (WM) is a rare lymphoproliferative disorder. Up to now, therapeutic choice was not influenced by the biological characteristics of the disease. Here, we will review how recent advances in biology in WM may affect therapy strategy.Recent Findings: Recently, WM has been described as a new oncogenic model. MyD88 mutation has been described as a key driver mutation and has functional consequences which could be targeted. Other mutations, such as CXCR4 or TP53, have been reported. These mutations are associated with different clinical presentation, prognosis, and treatment response.Summary: Mutational status may influence therapeutic choice in some patients but additional data are required. New targeted therapies are on development
New Twists in Ovarian Stimulation and Their Practical Implications
International audienceOvarian stimulation (OS) has for objective to induce multiple ovulation in order to yield a multiple oocyte harvest and offer multiple embryos available for transfer thereby increasing the efficacy of ART. Originally, the primary risk associated with OS was the occurrence of frank ovarian hyperstimulation syndrome (OHSS), a possibly dreadful-sometime fatal-complication of ART. These fears limited the number of oocytes aimed for during OS in order to curb the risk of OHSS. On the contrary, the meager implantation rates of the early days of ART led to easily transfer multiple embryos in order to achieve acceptable pregnancy rates. Today the perspectives have changed. The advent of antagonist-based OS protocol and the possibility to trigger the ultimate phase of oocyte maturation with GnRH-a has allowed to reduce the risk of OHHS. Conversely, the markedly increased implantation rates of today's ART makes multiple pregnancy a worry that has come in the limelight worldwide, pushing the practice of single embryo transfer (SET)
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