151 research outputs found
Modelling the interaction of the Astro Bio Cube Sat with the Van Allen’s Belt radiative field using Monte Carlo transport codes
Purpose: The AstroBio Cube Satellite (ABCS) will deploy within the inner Van Allen belt on the Vega C Maiden Flight launch opportunity of the European Space Agency. At this altitude, ABCS will experience radiation doses orders of magnitude greater than in low earth orbit, where CubeSats usually operate. The paper aims to estimate the irradiation effect on the ABCS payload in the orbital condition, their possible mitigation designing shielding solutions and performs a preliminary representativity simulation study on the ABCS irradiation with fission neutron at the TAPIRO (TAratura Pila Rapida Potenza 0) nuclear research reactor facility at ENEA. Methods: We quantify the contributions of geomagnetically trapped particles (electron and proton), Galactic Cosmic Rays (GCR ions), Solar energetic particle within the ABCS orbit using the ESA’s SPace ENVironment information system. FLUKA (Fluktuierende Kaskade—Fluctuating Cascade) code models the ABCS interaction with the orbital source. Results: We found a shielding solution of the weight of 300 g constituted by subsequent layers of tungsten, resins, and aluminium that decreases on average the 20% overall dose rate relative to the shielding offered by the only satellite’s structure. Finally, simulations of neutron irradiation of the whole ABCS structure within the TAPIRO’s thermal column cavity show that a relatively short irradiation time is requested to reach the same level of 1 MeV neutron Silicon equivalent damage of the orbital source. Conclusions: The finding deserves the planning of a future experimental approach to confirm the TAPIRO’s performance and establish an irradiation protocol for testing aerospatial electronic components
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Charge-transfer energy in iridates: A hard x-ray photoelectron spectroscopy study
We have investigated the electronic structure of iridates in the double perovskite crystal structure containing either Ir4+ or Ir5+ using hard x-ray photoelectron spectroscopy. The experimental valence band spectra can be well reproduced using tight-binding calculations including only the Ir 5d, O 2p, and O 2s orbitals with parameters based on the downfolding of the density-functional band structure results. We found that, regardless of the A and B cations, the A2BIrO6 iridates have essentially zero O 2p to Ir 5d charge-transfer energies. Hence double perovskite iridates turn out to be extremely covalent systems with the consequence being that the magnetic exchange interactions become very long ranged, thereby hampering the materialization of the long-sought Kitaev physics. Nevertheless, it still would be possible to realize a spin-liquid system using the iridates with a proper tuning of the various competing exchange interactions
Increase of Parkin and ATG5 plasmatic levels following perinatal hypoxic‐ischemic encephalopathy
Brain injury at birth is an important cause of neurological and behavioral disorders. Hypoxic‐ischemic encephalopathy (HIE) is a critical cerebral event occurring acutely or chronically at birth with high mortality and morbidity in newborns. Therapeutic strategies for the prevention of brain damage are still unknown, and the only medical intervention for newborns with moderate‐to‐severe HIE is therapeutic hypothermia (TH). Although the neurological outcome depends on the severity of the initial insult, emerging evidence suggests that infants with mild HIE who are not treated with TH have an increased risk for neurodevelopmental impairment; in the current clinical setting, there are no specific or validated biomarkers that can be used to both correlate the severity of the hypoxic insult at birth and monitor the trend in the insult over time. The aim of this work was to examine the presence of autophagic and mitophagic proteins in bodily fluids, to increase knowledge of what, early at birth, can inform therapeutic strategies in the first hours of life. This is a prospective multicentric study carried out from April 2019 to April 2020 in eight third‐level neonatal intensive care units. All participants have been subjected to the plasma levels quantification of both Parkin (a protein involved in mitophagy) and ATG5 (involved in autophagy). These findings show that Parkin and ATG5 levels are related to hypoxic‐ischemic insult and are reliable also at birth. These observations suggest a great potential diagnostic value for Parkin evaluation in the first 6 h of life
Epidemiological and clinical features of rotavirus among children younger than 5 years of age hospitalized with acute gastroenteritis in Northern Italy
BACKGROUND: Rotavirus is the major cause of acute gastroenteritis and severe dehydrating diarrhea in young children.
METHODS: To estimate the proportion of hospital admissions for rotavirus acute gastroenteritis and identify the circulating G and P genotypes among children under five years of age, we conducted a prospective observational study from January to December 2008, recruiting children consecutively admitted to six hospitals in Milan and nearby towns in northern Italy. Typing was done on stool samples by reverse transcriptase polymerase chain reaction amplification.
RESULTS: Of the 521 stool samples from children with acute gastroenteritis, 34.9% (95%CI, 30.8 to 39.2%) were rotavirus-positive. Two thirds (67.6%) were under two years of age, and 13.2% were under six months. The predominant G type was G1 (40.7%), followed by G9 (22.5%), G2 (13.2%), G3 (5.5%), G4 (3.8%) and G10 (1.6%). Twenty-one (11.7%) mixed-G infections were identified: G1+G10 (8.8%); G1+G9 (1.6%); and G2+G10 (1.2%). Only P[8] (67.6%) and P[4] (12.6%) types were P genotyped. The predominant single G/P combination was G1P[8] (39.7%), followed by G9P[8] (25.3%), G2P[4] (14.3%), and G3P[8] (4.1%). All G-mixed types combined with P[8].
CONCLUSIONS: These findings show an high prevalence of rotavirus infections among children admitted to hospital for acute gastroenteritis caused by different rotavirus strains circulating in the area studied
The SSDC Role in the LICIACube Mission: Data Management and the MATISSE Tool
Light Italian Cubesat for Imaging of Asteroids (LICIACube) is an Italian mission managed by the Italian Space
Agency (ASI) and part of the NASA Double Asteroid Redirection Test (DART) planetary defense mission. Its
main goals are to document the effects of the DART impact on Dimorphos, the secondary member of the (65803)
Didymos binary asteroid system, characterizing the shape of the target body and performing dedicated scientific
investigations on it. Within this framework, the mission Science Operations Center will be managed by the Space
Science Data Center (ASI-SSDC), which will have the responsibility of processing, archiving, and disseminating
the data acquired by the two LICIACube onboard cameras. In order to better accomplish this task, SSDC also plans
to use and modify its scientific webtool Multi-purpose Advanced Tool for Instruments for the solar system
Exploration (MATISSE), making it the primary tool for the LICIACube data analysis, thanks to its advanced
capabilities for searching and visualizing data, particularly useful for the irregular shapes common to several small
bodies
C/EBPβ-Thr217 Phosphorylation Signaling Contributes to the Development of Lung Injury and Fibrosis in Mice
mice are refractory to Bleomycin-induced lung fibrosis the molecular mechanisms remain unknown. Here we show that blocking the ribosomal S-6 kinase (RSK) phosphorylation of the CCAAT/Enhancer Binding Protein (C/EBP)-β on Thr217 (a RSK phosphoacceptor) with either a single point mutation (Ala217), dominant negative transgene or a blocking peptide containing the mutated phosphoacceptor ameliorates the progression of lung injury and fibrosis induced by Bleomycin in mice. mice with a cell permeant, C/EBPβ peptide that inhibits phosphorylation of C/EBPβ on Thr217 (40 µg instilled intracheally on day-2 and day-6 after the single Bleomycin dose) also blocked the progression of lung injury and fibrosis induced by Bleomycin. Phosphorylation of human C/EBPβ on Thr266 (human homologue phosphoacceptor) was induced in collagen-activated human lung fibroblasts in culture as well as in activated lung fibroblasts in situ in lungs of patients with severe lung fibrosis but not in control lungs, suggesting that this signaling pathway may be also relevant in human lung injury and fibrosis.These data suggest that the RSK-C/EBPβ phosphorylation pathway may contribute to the development of lung injury and fibrosis
TLR9-induced interferon β is associated with protection from gammaherpesvirus-induced exacerbation of lung fibrosis
Abstract
Background
We have shown previously that murine gammaherpesvirus 68 (γHV68) infection exacerbates established pulmonary fibrosis. Because Toll-like receptor (TLR)-9 may be important in controlling the immune response to γHV68 infection, we examined how TLR-9 signaling effects exacerbation of fibrosis in response to viral infection, using models of bleomycin- and fluorescein isothiocyanate-induced pulmonary fibrosis in wild-type (Balb/c) and TLR-9-/- mice.
Results
We found that in the absence of TLR-9 signaling, there was a significant increase in collagen deposition following viral exacerbation of fibrosis. This was not associated with increased viral load in TLR-9-/- mice or with major alterations in T helper (Th)1 and Th2 cytokines. We examined alveolar epithelial-cell apoptosis in both strains, but this could not explain the altered fibrotic outcomes. As expected, TLR-9-/- mice had a defect in the production of interferon (IFN)-β after viral infection. Balb/c fibroblasts infected with γHV68 in vitro produced more IFN-β than did infected TLR-9-/- fibroblasts. Accordingly, in vitro infection of Balb/c fibroblasts resulted in reduced proliferation rates whereas infection of TLR-9-/- fibroblasts did not. Finally, therapeutic administration of CpG oligodeoxynucleotides ameliorated bleomycin-induced fibrosis in wild-type mice.
Conclusions
These results show a protective role for TLR-9 signaling in murine models of lung fibrosis, and highlight differences in the biology of TLR-9 between mice and humans.http://deepblue.lib.umich.edu/bitstream/2027.42/112877/1/13069_2011_Article_57.pd
Role of host genetics in fibrosis
Fibrosis can occur in tissues in response to a variety of stimuli. Following tissue injury, cells undergo transformation or activation from a quiescent to an activated state resulting in tissue remodelling. The fibrogenic process creates a tissue environment that allows inflammatory and matrix-producing cells to invade and proliferate. While this process is important for normal wound healing, chronicity can lead to impaired tissue structure and function
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