417 research outputs found
Photometric and spectroscopic variability of 53 Per
A new investigation of the variability of the SPB-type star 53 Per is
presented. The analysis of the BRITE photometry allowed us to determine eight
independent frequencies and the combination one. Five of these frequencies and
the combination one were not known before. In addition, we gathered more than
1800 new moderate and high-resolution spectra of 53 Per spread over
approximately six months. Their frequency analysis revealed four independent
frequencies and the combination one, all consistent with the BRITE results.Comment: 2 pages, accepted for publication in the Proceedings of the PAS
(Proc. of the 2nd BRITE Science conference, Innsbruck
A fixed combination of probiotics and herbal extracts attenuates intestinal barrier dysfunction from inflammatory stress in an in vitro model using Caco-2 cells.
Background: Inflammatory Bowel Diseases (IBD), are considered a growing global disease, with about ten million people being affected worldwide. Maintenance of intestinal barrier integrity is crucial for preventing IBD onset and exacerbations. Some recent patents regarding oily formulations containing probiotics (WO2010122107A1 and WO2010103374A9) and the use of probiotics for gastrointestinal complaints (US20110110905A1 and US9057112B2) exist, or are pending application. Objective: In this work, we studied the effect of a fixed combination of registered Lactobacillus reuteri and Lactobacillus acidophilus strains and herbal extracts in an in vitro inflammation experimental model. Methods: Caco-2 cell monolayer was exposed to INF-\u3b3+TNF-\u3b1 or to LPS; Trans Epithelial Electrical Resistance (TEER) and paracellular permeability were investigated. ZO-1 and occludin Tight Junctions (TJs) were also investigated by mean of immunofluorescence. Results: Pre-treatment with the fixed combination of probiotics and herbal extracts prevented the inflammation-induced TEER decrease, paracellular permeability increase and TJs translocation. Conclusions: In summary, the fixed combination of probiotics and herbal extracts investigated in this research was found to be an interesting candidate for targeting the re-establishment of intestinal barrier function in IBD conditions
CAOS spectroscopy of Am stars Kepler targets
The {\it Kepler} space mission and its {\it K2} extension provide photometric
time series data with unprecedented accuracy. These data challenge our current
understanding of the metallic-lined A stars (Am stars) for what concerns the
onset of pulsations in their atmospheres. It turns out that the predictions of
current diffusion models do not agree with observations. To understand this
discrepancy, it is of crucial importance to obtain ground-based spectroscopic
observations of Am stars in the {\it Kepler} and {\it K2} fields in order to
determine the best estimates of the stellar parameters.
In this paper, we present a detailed analysis of high-resolution
spectroscopic data for seven stars previously classified as Am stars. We
determine the effective temperatures, surface gravities, projected rotational
velocities, microturbulent velocities and chemical abundances of these stars
using spectral synthesis. These spectra were obtained with {\it CAOS}, a new
instrument recently installed at the observing station of the Catania
Astrophysical Observatory on Mt. Etna. Three stars have already been observed
during quarters Q0-Q17, namely: HD\,180347, HD\,181206, and HD\,185658, while
HD\,43509 was already observed during {\it K2} C0 campaign.
We confirm that HD\,43509 and HD\,180347 are Am stars, while HD 52403,
HD\,50766, HD\,58246, HD\,181206 and HD\,185658 are marginal Am stars. By means
of non-LTE analysis, we derived oxygen abundances from O{\sc
I}7771--5{\AA} triplet and we also discussed the results obtained with
both non-LTE and LTE approaches.Comment: accepted in MNRAS main journal 13 pages, 11 figures, 3 tables. arXiv
admin note: text overlap with arXiv:1404.095
Exploratory study of the EU-DEMO Water-Cooled Lithium Lead breeding blanket behaviour in case of loss of cooling capability
Within the framework of the European Roadmap to the realization of fusion energy, a strong international cooperation is ongoing to develop a Breeding Blanket (BB) system for the EU-DEMO reactor. Although it is still to be decided whether the DEMO in-vessel components should perform any safety function, the pursuing of robust blanket concepts able to handle upset and accidental loading conditions has been always seen as good practice in fusion reactor engineering to enhance the inherent plant safety performances. Amongst the several classes of events that might challenge the BB structural integrity, the large Loss of Coolant Accident is one of the most relevant because it usually leads to a fast loss of cooling capability of the structures. Due to the characteristic of the tokamak assembly, the behaviour of each blanket segment during a sudden loss of cooling capability does not depend only upon distinguishing features of the component itself. In fact, the overall transient can be governed by conditions established in surrounding elements, like adjacent blanket segments and vacuum vessel, as well as by the plasma shutdown strategies adopted to protect the reactor. The scope of the activity herein presented is to make a preliminary assessment of the intrinsic capability of EU-DEMO tokamak architecture to cope with the loss of cooling in the Water-Cooled Lithium Lead (WCLL) BB concept. Evaluation of BB thermal field in short and medium term under simplified, yet conservative, assumptions was carried out for four transient scenarios with the aim of investigating the response of the structure in case of: a) fast or soft plasma shutdown, and b) different blanket cooling schemes. Moreover, the WCLL BB thermo-mechanical response in the most critical time steps has been assessed. The obtained results shall help for future decisions on safety systems/action to be implemented to cope with accidents
Structural assessment of the EU-DEMO water-cooled lead lithium central outboard blanket segment adopting the sub-modelling technique
The development of a sound conceptual design of the Water-Cooled Lead Lithium Breeding Blanket (WCLL BB) is pivotal to make a breakthrough towards the selection of the driver blanket concept for the EU-DEMO. To achieve this goal, an intense research campaign has been performed at the University of Palermo, in cooperation with ENEA Brasimone, under the umbrella of EUROfusion. In this paper, structural analyses of different poloidal regions of the WCLL BB Central Outboard Blanket (COB) segment are reported. In particular, starting from the results of the thermo-mechanical analysis of the whole WCLL BB COB segment, the sub-modelling technique has been applied to the most significant poloidal regions, located at the top, middle and bottom of the segment. The aim is to focus on the stress field locally arising under purposely selected steady-state nominal and accidental loading scenarios. The nominal BB operating conditions, as well as steady-state scenarios derived from both the in-box LOCA and Vertical Plasma Disruption accidents have been considered. Thanks to the sub-modelling approach, the deformative action of the entire segment can be imposed at the boundaries of each local model to realistically assess its structural performances. Moreover, each local model reproduces structural details not included in the global one, such as the Segment Box (SB) cooling channels. Then, the structural behaviour of the selected regions has been assessed in compliance with the RCC-MRx code. The obtained results highlighted that the structural behaviour predicted by the whole segment analysis is similar to that predicted by sub-modelling calculations within the Stiffening Plates, whereas the application of the sub-modelling is a must to investigate in detail the SB structural performances. In addition, results indicate that the BB attachments should be revised, as they contribute to produce the WCLL COB large deformation originating excessive stresses, mainly within the equatorial region
Juzgando crÃmenes de lesa humanidad: avances, retrocesos y qué podemos aprender de la experiencia,
The article presents the context of the last military dictatorship in Argentina, and the subsequent path in the prosecution of crimes against humanity that took place during that period. It describes how the amnesties and pardon laws were used in the Argentine case, and analyzes the incompatibility of these mechanisms in the prosecution of crimes against humanity, due to the international commitments and obligations to protect the human rights subscribed by the States. In addition, it explores the role of victims and the concept of reparation, a fundamental element in this kind of processes and particularly in criminal law. El artÃculo expone el contexto de la última dictadura militar en la Argentina, y el posterior camino en el juzgamiento de los crÃmenes de lesa humanidad que tuvieron lugar en ese perÃodo. Se describe cómo se utilizaron las leyes amnistÃas e indulto en el caso argentino, y se analiza la incompatibilidad de estos mecanismos en el juzgamiento de delitos de lesa humanidad, en virtud de los compromisos y obligaciones internacionales de protección de los derechos humanos de suscriptos por los Estados. Además, se estudia el rol de las vÃctimas y el concepto de reparación, un elemento primordial en este tipo de procesos y en particular en el derecho penal
Persistent dysregulation of DNA methylation in cells with arsenic-induced genomic instability
The mechanisms by which arsenic-induced genomic instability is initiated and maintained are poorly understood. In previous studies long-term progression of chromosomal instability was typified by increasing aneuploidy in Chinese hamster V79 and human keratinocyte cells treated with arsenite for a 24 hr exposure period followed by growth in arsenic-free medium for 40-120 cell generations. In the current study the role of progressive DNA methylation changes was evaluated in long-term cell cultures after brief arsenite treatments as above. We have found altered genomic methylation patterns in cells that were briefly exposed to arsenic with evidence for widespread dysregulation of CpG methylation that persists for many population doublings after the treatment.
In V79 cell populations, progressive aneuploidy increases were notable by 50 cell generations after a 24 hr exposure to 1-10 uM arsenite. Dicentric chromosomes and/or telomeric associations, as well as complex chromosome rearrangements, occurred by 90 cells generations post treatment; and mutator and transformed phenotypes began to appear thereafter. This increasing genomic instability correlated with modifications of global DNA methylation patterns in V79 cells evaluated by 5-methylcytosine antibody binding and MeSAP-PCR. The results show that short-term exposure to arsenite induced an apparent genome hypomethylating effect within a short time after exposure.
In identical protocols using human HaCaT keratinocytes exposed to low doses of arsenite (0.05-0.1 M) for 24 hr, genomewide methylation levels were measured by LINE1 pyrosequencing and gene-specific methylation status was assessed by Methylation-Specific-PCR for up to 40 generations post exposure. Global demethylation following treatment was supported by preliminary LINE-1 studies. Moreover, the study of gene-specific MSP and determination of expression levels by RT-PCR of several genes (p16, hMLH1, hMSH2, DNMT1, DNMT3a and DNMT3b) demonstrated that hMSH2 gene was epigenetically regulated by arsenite and that down regulation of DNMT3a and DNMT3b genes occurred in an arsenite dose-dependent manner.
The results reported here demonstrate that acute 24 hr arsenic exposure promptly induces genome wide DNA hypomethylation, and support the hypothesis that the cells continue to undergo epigenetic reprogramming both at the gene and genomic levels in the absence of further arsenite treatment; thus likely contributing to long-lasting genomic instability that manifests as aberrant chromosomal, mutator and cell transformation effects
ALLELIC VARIANTS OF CYP2E1 GENE IN HEPATOCARCINOMA PATIENTS AND IN HEPATIC TUMOR CELL LINES
Background and Aims: Hepatic enzyme CYP2E1 is involved in the
metabolism of a number of exogenous and endogenous substances
(i.e. ethanol, drugs and chemical carcinogens). Being polymorphic,
CYP2E1 gene can give different xeno-metabolic capabilities in a
population and it is well known that inadequate or no enzymatic
deactivation of xenobiotics could induce an increased susceptibility
to disease and cancer. In particular, one of the 5 -flanking region
polymorphisms, able to differentiate CYP2E1 gene transcriptional
activity, is caused by the appearance/disappearance of RsaI and
PstI restriction sites, which generates two different alleles, namely
*C1(Rsa+/Pst−) and *C2(Rsa−/Pst+) respectively, reported to be in
complete linkage disequilibrium.
Methods: To confirm the existence of a correlation between some
particular CYP2E1 genotypes/haplotypes and hepatocarcinoma, we
determined CYP2E1 PstI/RsaI genotypes/haplotypes by RFLP-PCR in
a cohort of central western Sicily hepatocarcinoma patients and in
a population of healthy students from the same geographic area.
Results: In hepatocarcinoma patients, modal genotype association
was Rsa++/Pst−−, corresponding to CYP2E1 *C1/*C1 haplotype,
whereas the Rsa+−/Pst−+ association, equivalent to CYP2E1 *C1/*C2
haplotype, resulted to have the lowest frequency both in patients
and in controls. Moreover, both in patients and in controls, noncanonical
genotype associations were frequent and arose from
a no-linkage disequilibrium between the two polymorphic sites.
Other authors reported this finding as a rare occurrence. Thus,
from analysis of only one restriction site, Rsa++ genotype was
approximately 1.5-fold more frequent in patients than in controls,
and the non-canonical Rsa+− genotype was found relatively
frequent in patients. Moreover, HuH7 and HA22T transformed
hepatocarcinoma cell lines also showed the Rsa+− genotype.
Conclusions: These results suggest that the presence in CYP2E1
genotype of at least one allele with an Rsa I restriction site is
correlated with hepatocarcinoma. As this site is known a consensus
sequence for some specific CYP gene transcription factors, like
HNF-1, it may be supposed that a single nucleotide polymorphism
can alter the possibility of HNF-1 to bind CYP2E1 promoter. This
could determine a marked change in the transcriptional activity
of the gene, incompetence in xenobiotic metabolism or in toxic
substance deactivation and an increased susceptibility to neoplastic
diseases, such as hepatocarcinoma
V363 Cas: a new lithium rich Galactic Cepheid
Classical Cepheids (DCEPs) are important astrophysical objects not only as
standard candles in the determination of the cosmic distance ladder, but also
as a testbed for the stellar evolution theory, thanks to the strict connection
between their pulsation [period(s), amplitudes] and stellar (luminosity, mass,
effective temperature, metallicity) parameters. We aim at unveiling the nature
of the Galactic DCEP V363 Cas and other DCEPs showing cosmic abundances of
lithium in their atmospheres. We have collected three epochs high-resolution
spectroscopy for V363 Cas with HARPS-N@TNG. Accurate stellar parameters:
effective temperatures, gravities, micro-turbulences, radial velocities, and
metal abundances were measured for this star. We detected a lithium abundance
of A(Li)=2.86+-0.10 dex, along with iron, carbon and oxygen abundances of
[Fe/H]=-0.30+-0.12 dex, [C/H]=-0.06+-0.15 dex and [O/H]=0.00+-0.12 dex. V363
Cas is the fifth among the Milky Way DCEPs to exhibit a Li-rich feature. An
analysis of historical time-series spanning a hundred year interval shows that
the period of V363 Cas is increasing, with a sharp acceleration after
HJD=2453000. This is a clear hint of first crossing of the instability strip.
Our results favour the scenario in which the five Galactic Li-rich DCEPs are
first-crossing the instability strip having had slowly-rotating progenitors
during their main sequence phase.Comment: Accepted on Astronomy and Astrophysics (Letter). 5 Page
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