290 research outputs found

    Highly efficient multilayer organic pure-blue-light emitting diodes with substituted carbazoles compounds in the emitting layer

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    Bright blue organic light-emitting diodes (OLEDs) based on 1,4,5,8,N-pentamethylcarbazole (PMC) and on dimer of N-ethylcarbazole (N,N'-diethyl-3,3'-bicarbazyl) (DEC) as emitting layers or as dopants in a 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) matrix are described. Pure blue-light with the C.I.E. coordinates x = 0.153 y = 0.100, electroluminescence efficiency \eta_{EL} of 0.4 cd/A, external quantum efficiency \eta_{ext.} of 0.6% and luminance L of 236 cd/m2 (at 60 mA/cm2) were obtained with PMC as an emitter and the 2,9-dimethyl-4,7-diphenyl-1,10-phenantroline (BCP) as a hole-blocking material in five-layer emitting devices. The highest efficiencies \eta_{EL.} of 4.7 cd/A, and \eta_{ext} = 3.3% were obtained with a four-layer structure and a DPVBi DEC-doped active layer (CIE coordinates x = 0.158, y=0.169, \lambda_{peak} = 456 nm). The \eta_{ext.} value is one the highest reported at this wavelength for blue OLEDs and is related to an internal quantum efficiency up to 20%

    Investigations sur une crise de mortalitĂ© Ă  Boulogne-sur-Mer (Pas-de-Calais, XVIIIe s.). HypothĂšses d’interprĂ©tation

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    La fouille prĂ©ventive du site de l’Ilot Saint-Louis Ă  Boulogne-sur-Mer (Pas-de-Calais) a livrĂ© sept sĂ©pultures multiples, soit au total 39 individus datĂ©s du dĂ©but du XVIIIe s. La simultanĂ©itĂ© des dĂ©pĂŽts osseux associĂ©e Ă  la contemporanĂ©itĂ© des diffĂ©rentes structures et Ă  la rĂ©currence du phĂ©nomĂšne nous permet d’interprĂ©ter ce site comme le rĂ©sultat d’une crise brutale de mortalitĂ©. Sur la base d’arguments historiques, archĂ©ologiques et anthropologiques, nous avons Ă©liminĂ© l’hypothĂšse d’un Ă©pisode belliqueux ou d’une famine et privilĂ©giĂ© celle d’une Ă©pidĂ©mie. La distribution des sexes est Ă©quilibrĂ©e et l’effectif des adultes est sensiblement identique Ă  celui des sujets immatures. Toutefois le rapport des diffĂ©rentes classes d’ñge d’immatures fait apparaĂźtre certaines particularitĂ©s lorsqu’on le compare Ă  celui d’une dĂ©mographie dite « naturelle ». Ces spĂ©cificitĂ©s discutĂ©es au regard de diverses sources (historiques, mĂ©dicales, dĂ©mographiques) nous permettent d’écarter certaines Ă©pidĂ©mies. Seule la variole s’est rĂ©vĂ©lĂ©e ĂȘtre une piste de recherche intĂ©ressante bien qu’il ne soit pas possible d’écarter totalement d’autres maladies mal documentĂ©es et pourtant rĂ©currentes pour la pĂ©riode concernĂ©e. Une interprĂ©tation dĂ©finitive de l’épidĂ©mie responsable des dĂ©cĂšs survenus Ă  Boulogne ne pourra ĂȘtre proposĂ©e qu’à partir de recherches complĂ©mentaires, notamment par une Ă©tude plus complĂšte des sources archivistiques mais Ă©galement par des analyses en palĂ©obiochimie molĂ©culaire permettant l’identiïŹcation de germes bien spĂ©ciïŹques.Seven simultaneous burials, representing a total of 39 individuals and dated as early as the 18th century, were found at the excavation site of l’Ilot Saint-Louis at Boulogne-sur-Mer (Pas-de-Calais). The simultaneity of the bone deposits, the contemporaneity of the different burial structures and the recurrence of the phenomenon lead us to believe that the site is the result of an abrupt peak in mortality. Historical, archaeological and anthropological arguments rule out the hypotheses of war or famine as the cause of this peak, leaving that of an epidemic. Sex distribution is well-balanced and the number of adult and immature individuals is almost identical. However certain peculiarities in the ratio between the different groups of immature individuals and that of a demography considered “natural” become apparent. These peculiarities, when studied historically, medically and demographically, permit us to eliminate certain epidemics from consideration. The most likely proposition would seem to be smallpox, although other poorly documented illnesses, known to be recurrent at that time, cannot be totally excluded. A more precise explanation of the epidemic responsible for the deaths at Boulogne will need further research, particularly a more thorough study of historical records, but also by molecular palaeobiochemical analysis, in order to identify speciïŹc pathogens

    Doped and non-doped organic light-emitting diodes based on a yellow carbazole emitter into a blue-emitting matrix

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    A new carbazole derivative with a 3,3'-bicarbazyl core 6,6'-substituted by dicyanovinylene groups (6,6'-bis(1-(2,2'-dicyano)vinyl)-N,N'-dioctyl-3,3'-bicarbazyl; named (OcCz2CN)2, was synthesized by carbonyl-methylene Knovenagel condensation, characterized and used as a component of multilayer organic light-emitting diodes (OLEDs). Due to its -donor-acceptor type structure, (OcCz2CN)2 was found to emit a yellow light at max=590 nm (with the CIE coordinates x=0.51; y = 0.47) and was used either as a dopant or as an ultra-thin layer in a blue-emitting matrix of 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi). DPVBi (OcCz2CN)2-doped structure exhibited, at doping ratio of 1.5 weight %, a yellowish-green light with the CIE coordinates (x = 0.31; y = 0.51), an electroluminescence efficiency EL=1.3 cd/A, an external quantum efficiency ext= 0.4 % and a luminance L= 127 cd/m2 (at 10 mA/cm2) whereas for non-doped devices utilizing the carbazolic fluorophore as a thin neat layer, a warm white with CIE coordinates (x = 0.40; y= 0.43), EL= 2.0 cd/A, ext= 0.7 %, L = 197 cd/m2 (at 10 mA/cm2) and a color rendering index (CRI) of 74, were obtained. Electroluminescence performances of both the doped and non-doped devices were compared with those obtained with 5,6,11,12-tetraphenylnaphtacene (rubrene) taken as a reference of highly efficient yellow emitter

    Les crùnes déformés de Saint-Etienne (Beaune, CÎte d'Or, Ve-VIe siÚcles). Données archéologiques et anthropologiques

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    International audienceThe sector of the Saint-Étienne necropolis (Beaune), reveals the existence of two clearly separated zones which are characterized by different funeral and cultural practices: tomb architecture, archaeological material and artificially deformed crania. This seems to provide evidence of two distinct groups. A preliminary morpho-metrical study of four skulls and the examination of several CT scans of three of them, allow us to confirm the presence of artificial antero-posterior cranial deformations.Le secteur de la nĂ©cropole Saint-Étienne (Beaune), sur lequel a portĂ© notre Ă©tude, a rĂ©vĂ©lĂ© l'existence de deux zones nettement sĂ©parĂ©es se caractĂ©risant par des pratiques funĂ©raires et culturelles diffĂ©rentes : architecture des tombes, matĂ©riel d'accompagnement et crĂąnes dĂ©formĂ©s artificiellement. Ces diffĂ©rences semblent tĂ©moigner de l'existence de deux groupes distincts. Une Ă©tude prĂ©liminaire morphomĂ©trique de quatre crĂąnes ainsi que l'examen de plusieurs coupes scanographiques de trois d'entre eux, ont permis de confirmer l'existence de dĂ©formations crĂąniennes artificielles de type antĂ©ro-postĂ©rieur

    A novel dietary multi-strain yeast fraction modulates intestinal toll-like-receptor signalling and mucosal responses of rainbow trout (Oncorhynchus mykiss)

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    This study was conducted to evaluate the mucosal immune responses of rainbow trout when supplementing an experimental formulated feed with multi-strain yeast fraction product (Saccharomyces cerevisiae and Cyberlindnera jardinii). In total, 360 fish (initial BW 23.1 ± 0.2 g) were randomly allotted into three dietary treatments in an 8-week feeding trial. The dietary treatments included basal diet (control) and control + 1.5 g/kg multi-strain yeast fraction product (MsYF) fed continuously and pulsed every two weeks between control and MsYF diet. No negative effects on growth performance of feeding the MsYF supplemented diet were observed. SGR and FCR averaged 2.30 ± 0.03%/day and 1.03 ± 0.03, respectively, across experimental groups. Muscularis thickness in the anterior intestine after 8 weeks of feeding was significantly elevated by 44.3% in fish fed the MsYF continuously, and by 14.4% in fish fed the MsYF pulsed (P 50% increase) intestine were observed after 8 weeks of feeding the MsYF supplemented diet (P10% reduction). The gene expression analysis of the intestine revealed significant elevations in expression of tlr2, il1r1, irak4, and tollip2 after 4 weeks of feeding the MsYF. Significant elevations in effector cytokines tnfα, il10 and tgfÎČ were observed after 4 weeks of feeding the MsYF regime. After 8 weeks significant elevations in the gene expression levels of il1ÎČ, ifnÎł, and il12 were observed in fish fed the MsYF. Likewise, the expression of the transcription factor gata3 was significantly elevated (P<0.01). Supplementation of the multi-strain yeast fraction product positively modulates the intestinal mucosal response of rainbow trout through interaction with toll-like receptor two signalling pathway and potential for increased capacity of delivery of antigens to the underlying mucosal associated lymphoid tissue

    Ancient Yersinia pestis genomes from across Western Europe reveal early diversification during the First Pandemic (541–750)

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    The first historically documented pandemic caused by Yersinia pestis began as the Justinianic Plague in 541 within the Roman Empire and continued as the so-called First Pandemic until 750. Although paleogenomic studies have previously identified the causative agent as Y. pestis, little is known about the bacterium’s spread, diversity, and genetic history over the course of the pandemic. To elucidate the microevolution of the bacterium during this time period, we screened human remains from 21 sites in Austria, Britain, Germany, France, and Spain for Y. pestis DNA and reconstructed eight genomes. We present a methodological approach assessing single-nucleotide polymorphisms (SNPs) in ancient bacterial genomes, facilitating qualitative analyses of low coverage genomes from a metagenomic background. Phylogenetic analysis on the eight reconstructed genomes reveals the existence of previously undocumented Y. pestis diversity during the sixth to eighth centuries, and provides evidence for the presence of multiple distinct Y. pestis strains in Europe. We offer genetic evidence for the presence of the Justinianic Plague in the British Isles, previously only hypothesized from ambiguous documentary accounts, as well as the parallel occurrence of multiple derived strains in central and southern France, Spain, and southern Germany. Four of the reported strains form a polytomy similar to others seen across the Y. pestis phylogeny, associated with the Second and Third Pandemics. We identified a deletion of a 45-kb genomic region in the most recent First Pandemic strains affecting two virulence factors, intriguingly overlapping with a deletion found in 17th- to 18th-century genomes of the Second Pandemic. © 2019 National Academy of Sciences. All rights reserved

    The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths

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    We present the Planck Sky Model (PSM), a parametric model for the generation of all-sky, few arcminute resolution maps of sky emission at submillimetre to centimetre wavelengths, in both intensity and polarisation. Several options are implemented to model the cosmic microwave background, Galactic diffuse emission (synchrotron, free-free, thermal and spinning dust, CO lines), Galactic H-II regions, extragalactic radio sources, dusty galaxies, and thermal and kinetic Sunyaev-Zeldovich signals from clusters of galaxies. Each component is simulated by means of educated interpolations/extrapolations of data sets available at the time of the launch of the Planck mission, complemented by state-of-the-art models of the emission. Distinctive features of the simulations are: spatially varying spectral properties of synchrotron and dust; different spectral parameters for each point source; modeling of the clustering properties of extragalactic sources and of the power spectrum of fluctuations in the cosmic infrared background. The PSM enables the production of random realizations of the sky emission, constrained to match observational data within their uncertainties, and is implemented in a software package that is regularly updated with incoming information from observations. The model is expected to serve as a useful tool for optimizing planned microwave and sub-millimetre surveys and to test data processing and analysis pipelines. It is, in particular, used for the development and validation of data analysis pipelines within the planck collaboration. A version of the software that can be used for simulating the observations for a variety of experiments is made available on a dedicated website.Comment: 35 pages, 31 figure

    Planck intermediate results. VIII. Filaments between interacting clusters

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    About half of the baryons of the Universe are expected to be in the form of filaments of hot and low density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories which are limited in sensitivity to the diffuse low density medium. The Planck satellite has provided hundreds of detections of the hot gas in clusters of galaxies via the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for studying extended low density media through the tSZ effect. In this paper we use the Planck data to search for signatures of a fraction of these missing baryons between pairs of galaxy clusters. Cluster pairs are good candidates for searching for the hotter and denser phase of the intergalactic medium (which is more easily observed through the SZ effect). Using an X-ray catalogue of clusters and the Planck data, we select physical pairs of clusters as candidates. Using the Planck data we construct a local map of the tSZ effect centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray maps of these pairs. After having modelled and subtracted the tSZ effect and X-ray emission for each cluster in the pair we study the residuals on both the SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a significant tSZ effect signal in the intercluster region beyond the virial radii of the clusters. A joint X-ray SZ analysis allows us to constrain the temperature and density of this intercluster medium. We obtain a temperature of kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&
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