10,938 research outputs found
Electrical field profile and doping in planar lead halide perovskite solar cells
Hybrid lead halide perovskites (PVKs) have emerged as novel materials for photovoltaics and have rapidly reached very large solar to electricity power conversion efficiencies. As occurring with other kind of solar technologies establishing the working energy-band diagram constitutes a primary goal for device physics analysis. Here, the macroscopic electrical field distribution is experimentally determined using capacitance-voltage and Kelvin probe techniques. Planar struc- tures comprising CH3NH3PbI3�����xClx PVK exhibit p-doping character and form a p-n heterojunc- tion with n-doped TiO2 compact layers. Depletion width at equilibrium within the PVK bulk has an extent about 300 nm (approximately half of the layer thickness), leaving as a consequence a significant neutral zone towards the anode contact. Charge collection properties are then accessi- ble relying on the relative weight that diffusion and drift have as carrier transport driven forces
Formation of Pd2Si on single-crystalline Si (100) at ultrafast heating rates : an in-situ analysis by nanocalorimetry
The kinetics of intermediate phase formation between ultrathin films of Pd (12 nm) and single-crystalline Si (100) is monitored by in-situ nanocalorimetry at ultrafast heating rates. The heat capacity curves show an exothermic peak related to the formation of Pd2Si. A kinetic model which goes beyond the conventional linear-parabolic growth to consider independent nucleation and lateral growth of Pd2Si along the interface and vertical growth mechanisms is developed to fit the calorimetric curves. The model is used to extract the effective interfacial nucleation/growth and diffusion coefficients at the unusually high temperatures of silicide formation achieved at very fast heating rates
Optimización de la hemoglobina preoperatoria en cirugía ortopédica mayor utilizando hierro intravenoso con o sin eritropoyetina. Estudio epidemiológico
Objetivo: Evaluar la efectividad del tratamiento con hierro intravenoso, solo o asociado a eritropoyetina (rHuEPO), mediante el incremento de hemoglobina (Hb). Como objetivo secundario se analizó la relación del incremento de Hb con los parámetros utilizados para evaluar la anemia. Material y método: Estudio observacional retrospectivo realizado en 2 centros entre enero de 2005 y diciembre de 2009. Se incluyeron pacientes sometidos a cirugía ortopédica electiva con déficit de hierro y que fueron tratados con hierro sacarosa intravenosos solo o asociado a rHuEPO. Se analizó la efectividad del tratamiento mediante la diferencia entre la Hb basal y la Hb previa a la cirugía y se valoró la relación entre los parámetros hematimétricos y del metabolismo del hierro con la efectividad del tratamiento. Resultados: Se incluyeron 412 pacientes que recibieron una mediana de 800mg de hierro sacarosa. A 125 pacientes (30,4%) se les asoció 2,4 viales de rHuEPO. El incremento de Hb fue de 0,8 (1,1) g/dL en los pacientes tratados con hierro intravenoso y de 1,5 (1,3) g/dL en los que se asoció rHuEPO (p<0,01). El incremento de Hb en los pacientes tratados con hierro se correlacionó con el porcentaje de hematíes hipocromos (r=0,52) y el valor del receptor soluble de la transferrina (r=0,59). Conclusiones: La efectividad del tratamiento con hierro sacarosa en pacientes con déficit de hierro para la optimización de la Hb preoperatoria fue moderada, siendo mayor con la administración adyuvante de eritropoyetina. La determinación de los parámetros funcionales del estado del hierro nos podría guiar para mejorar la efectividad del tratamiento
Histological and ultrastructural comparison of cauterization and thrombosis stroke models in immune-deficient mice
Background: Stroke models are essential tools in experimental stroke. Although several models of stroke have
been developed in a variety of animals, with the development of transgenic mice there is the need to develop a
reliable and reproducible stroke model in mice, which mimics as close as possible human stroke.
Methods: BALB/Ca-RAG2-/-gc-/- mice were subjected to cauterization or thrombosis stroke model and sacrificed at
different time points (48hr, 1wk, 2wk and 4wk) after stroke. Mice received BrdU to estimate activation of cell
proliferation in the SVZ. Brains were processed for immunohistochemical and EM.
Results: In both stroke models, after inflammation the same glial scar formation process and damage evolution
takes place. After stroke, necrotic tissue is progressively removed, and healthy tissue is preserved from injury
through the glial scar formation. Cauterization stroke model produced unspecific damage, was less efficient and
the infarct was less homogeneous compared to thrombosis infarct. Finally, thrombosis stroke model produces
activation of SVZ proliferation.
Conclusions: Our results provide an exhaustive analysis of the histopathological changes (inflammation, necrosis,
tissue remodeling, scarring...) that occur after stroke in the ischemic boundary zone, which are of key importance
for the final stroke outcome. This analysis would allow evaluating how different therapies would affect wound and
regeneration. Moreover, this stroke model in RAG 2-/- gC -/- allows cell transplant from different species, even
human, to be analyzed
Process slicing:a new mitigation tool for cyber-attacks against softwarised industrial environments
With the evolution of softwarised industrial infrastructures, there is an increasing need for more sophisticated cyber security solutions that can protect industrial processes from a rapidly evolving landscape of cyber threats. In this context, we present an agent-based approach that provides process monitoring, predictive process behaviour, and process control to give the organisations appropriate situational awareness in relation to cyber security threats, enabling them to re-actively or pro-actively detect attacks and respond to advanced persistent threats and multi-vector attacks. Our architectural solution is based on four agents: Process Inventory Agent (PIA), Process Monitoring Agent (PMA), Process Forecasting Agent (PFA), and the Process Slicing Control Agent (PSCA), which work together to deliver a novel mitigation tool to secure softwarised industrial environments. The architecture has been designed, prototyped, and validated in order to demonstrate the effectiveness of our solution. Experimental results show that the proposed solution can successfully mitigate different attacks in the concerned context
The 2HWC HAWC Observatory Gamma Ray Catalog
We present the first catalog of TeV gamma-ray sources realized with the
recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the
most sensitive wide field-of-view TeV telescope currently in operation, with a
1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an
instantaneous field of view >1.5 sr and >90% duty cycle, it continuously
surveys and monitors the sky for gamma ray energies between hundreds GeV and
tens of TeV.
HAWC is located in Mexico at a latitude of 19 degree North and was completed
in March 2015. Here, we present the 2HWC catalog, which is the result of the
first source search realized with the complete HAWC detector. Realized with 507
days of data and represents the most sensitive TeV survey to date for such a
large fraction of the sky. A total of 39 sources were detected, with an
expected contamination of 0.5 due to background fluctuation. Out of these
sources, 16 are more than one degree away from any previously reported TeV
source. The source list, including the position measurement, spectrum
measurement, and uncertainties, is reported. Seven of the detected sources may
be associated with pulsar wind nebulae, two with supernova remnants, two with
blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa
Searching for a link between the magnetic nature and other observed properties of Herbig Ae/Be stars and stars with debris disks
Among the 21 Herbig Ae/Be stars studied, new detections of a magnetic field
were achieved in six stars. For three Herbig Ae/Be stars, we confirm previous
magnetic field detections. The largest longitudinal magnetic field, =
-454+-42G, was detected in the Herbig Ae/Be star HD101412 using hydrogen lines.
No field detection at a significance level of 3sigma was achieved in stars with
debris disks. Our study does not indicate any correlation of the strength of
the longitudinal magnetic field with disk orientation, disk geometry, or the
presence of a companion. We also do not see any simple dependence on the
mass-accretion rate. However, it is likely that the range of observed field
values qualitatively supports the expectations from magnetospheric accretion
models giving support for dipole-like field geometries. Both the magnetic field
strength and the X-ray emission show hints for a decline with age in the range
of ~2-14Myrs probed by our sample supporting a dynamo mechanism that decays
with age. However, our study of rotation does not show any obvious trend of the
strength of the longitudinal magnetic field with rotation period. Furthermore,
the stars seem to obey the universal power-law relation between magnetic flux
and X-ray luminosity established for the Sun and main-sequence active dwarf
stars.Comment: 21 pages, 16 figures, 7 tables, accepted for publication in A&
Highlights from the Pierre Auger Observatory
The Pierre Auger Observatory is the world's largest cosmic ray observatory.
Our current exposure reaches nearly 40,000 km str and provides us with an
unprecedented quality data set. The performance and stability of the detectors
and their enhancements are described. Data analyses have led to a number of
major breakthroughs. Among these we discuss the energy spectrum and the
searches for large-scale anisotropies. We present analyses of our X
data and show how it can be interpreted in terms of mass composition. We also
describe some new analyses that extract mass sensitive parameters from the 100%
duty cycle SD data. A coherent interpretation of all these recent results opens
new directions. The consequences regarding the cosmic ray composition and the
properties of UHECR sources are briefly discussed.Comment: 9 pages, 12 figures, talk given at the 33rd International Cosmic Ray
Conference, Rio de Janeiro 201
Specific gene expression profiles and chromosomal abnormalities are associated with infant disseminated neuroblastoma
Background: Neuroblastoma (NB) tumours have the highest incidence of spontaneous remission, especially among the stage 4s NB subgroup affecting infants. Clinical distinction of stage 4s from lethal stage 4 can be difficult, but critical for therapeutic decisions. The aim of this study was to investigate chromosomal alterations and differential gene expression amongst infant disseminated NB subgroups. Methods: Thirty-five NB tumours from patients diagnosed at < 18 months (25 stage 4 and 10 stage 4s), were evaluated by allelic and gene expression analyses. Results: All stage 4s patients underwent spontaneous remission, only 48% stage 4 patients survived despite combined modality therapy. Stage 4 tumours were 90% near-diploid/tetraploid, 44% MYCN amplified, 77% had 1p LOH (50% 1p36), 23% 11q and/or 14q LOH (27%) and 47% had 17q gain. Stage 4s were 90% near-triploid, none MYCN amplified and LOH was restricted to 11q. Initial comparison analyses between stage 4s and 4 < 12 months tumours revealed distinct gene expression profiles. A significant portion of genes mapped to chromosome 1 (P < 0.0001), 90% with higher expression in stage 4s, and chromosome 11 (P = 0.0054), 91% with higher expression in stage 4. Less definite expression profiles were observed between stage 4s and 4 < 18m, yet, association with chromosomes 1 (P < 0.0001) and 11 (P = 0.005) was maintained. Distinct gene expression profiles but no significant association with specific chromosomal region localization was observed between stage 4s and stage 4 < 18 months without MYCN amplification. Conclusion: Specific chromosomal aberrations are associated with distinct gene expression profiles which characterize spontaneously regressing or aggressive infant NB, providing the biological basis for the distinct clinical behaviour
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