339 research outputs found
Highly efficient multilayer organic pure-blue-light emitting diodes with substituted carbazoles compounds in the emitting layer
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%
Doped and non-doped organic light-emitting diodes based on a yellow carbazole emitter into a blue-emitting matrix
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
Ancient Yersinia pestis genomes from across Western Europe reveal early diversification during the First Pandemic (541â750)
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 bacteriumâs 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
Polarization properties of coherent VUV light at 125 nm generated by sum-frequency four-wave mixing in mercury
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The human remains from the Lumentxa cave (Lekeitio, Biscay, Northern Iberian Peninsula): Paleobiology, Taphonomy and Chronology
Lumentxa is a classic site in Basque Prehistory, excavated in three different phases during the 20th century, which has yielded evidence of both Pleistocene and Holocene occupations. In this article, we present a detailed study of the human remains from this site including paleobiological, taphonomic, biomechanical and chronological
perspectives. The human assemblage comprises of a minimum number of seven individuals: three subadult and four adults, with both sexes represented, although part of the human collection is currently lost. We have obtained C14 dates from 4 of these 7 individuals indicating a prolonged funerary use of the cave from the Early Neolithic until
the Bronze Age. We observed some biases in the skeletal representation which could be due to differences in the excavation methods between field seasons and/or the action of carnivores, the latter being evident in at least three of the individuals. The taphonomic modifications are typical off those found in the post-abandonment phases in cave funerary contexts. The relatively low number of individuals compared with other
sites in the region and extended timespan over which the remains were deposited suggest that the cave was used only sporadically for funerary purposes. We report the first biomechanical data for a Neolithic individual from the Iberian Peninsula, which show greatest overall similarity to the Neolithic sample from France and Italy. Finally, the broad time period covered by the direct dates and the more complex taphonomic history than was previously assumed for such sites indicate that caution is warranted when assigning sepulchral caves to cultural periods in the Western Pyrenees when no direct 14C dates have been obtained
The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths
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
Methodology of the Virtual Reconstruction of Arquitectonic Heritage: Ambassador Vich's Palace in Valencia
The 19th century was disastrous as far as the conservation of architectonic heritage is concerned. The awareness of the importance of preserving monuments that has prevailed since the end of the last century was dazzlingly absent in the previous, leading both to the disappearance of representative heritage works and the plundering of many others. The present study establishes the methodological basis to proceed with the virtual reconstruction of many disappeared architectures, representative of emblematic architectonic typologies. A method based on the combination of deduction and induction allows benchmarks to be created that signify a starting point to which the key and specific elements of each building are later incorporated, from the data extracted from the conserved parts and the graphic, literary and archive documents. The result is the virtual recovery of the general outlines of the architecture: morphology of the plot, volumetry, exterior and interior facades, and the functional layout. The good results obtained in the study of the disappeared Ambassador Vich's Palace, allow the methodology to be extended to the analysis of other similar examples, serving investigators as a tool to carry out an arduous task of deciphering a trail that is increasingly fading with the passing of time.Galiana Agullo, M.; Mas Tomas, MDLA.; Lerma Elvira, C.; Peñalver MartĂnez, MJ.; Conesa Tejada, S. (2014). Methodology of the Virtual Reconstruction of Arquitectonic Heritage: Ambassador Vich's Palace in Valencia. International Journal of Architectural Heritage. 8(1):94-123. doi:10.1080/15583058.2012.672623S9412381Boix, V. 1979.Historical and topographic Valencia[in Spanish]. Vol. I261 S. A. Printing J. Rius.Estaban ChapaprĂa, J. (2001). ImpostaciĂłn del patio del Embajador Vich en el ex-convento del Carmen (Valencia). Loggia, Arquitectura & RestauraciĂłn, (12), 26. doi:10.4995/loggia.2001.3605Morrish, S. W., & Laefer, D. F. (2010). Web-Enabling of Architectural Heritage Inventories. International Journal of Architectural Heritage, 4(1), 16-37. doi:10.1080/15583050902731056Lotz, W. 1995.Architecture in Italy 1500â1600 [in Italian]35â37. ed. RizzoliYale University Press.Lourenço, P. B., Peña, F., & Amado, M. (2010). A Document Management System for the Conservation of Cultural Heritage Buildings. International Journal of Architectural Heritage, 5(1), 101-121. doi:10.1080/15583050903318382Vila Ferrer, S. (2001). La recuperaciĂłn del patio del palacio del Embajador Vich (Valencia). Loggia, Arquitectura & RestauraciĂłn, (12), 44. doi:10.4995/loggia.2001.3606Zonta, D., Pozzi, M., & Zanon, P. (2008). Managing the Historical Heritage Using Distributed Technologies. International Journal of Architectural Heritage, 2(3), 200-225. doi:10.1080/1558305080206369
Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways
It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers
Planck intermediate results. VIII. Filaments between interacting clusters
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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