850 research outputs found
Pre-Transplant Screening for Latent Adenovirus in Donors and Recipients
Human adenoviruses are frequent cause of slight self-limiting infections in immune competent subjects, while causing
life-threatening and disseminated diseases in immunocompromised patients, particularly in the subjects affected by acquired
immunodeficiency syndrome and in bone marrow and organ transplant recipients. Here, infections interest lungs, liver, encephalon,
heart, kidney and gastro enteric tract. To date, human adenoviruses comprise 51 serotypes grouped into seven species, among which
species C especially possesses the capability to persist in infected tissues. From numerous works, it emerges that in the recipient,
because of loss of immune-competence, both primary infection, via the graft or from the environment, and reactivated endogenous
viruses can be responsible for transplantation related adenovirus disease. The transplants management should include the evaluation
of anti-adenovirus pre-transplant screening similar to that concerning cytomegalovirus. The serological screening on
cytomegalovirus immunity is currently performed to prevent viral reactivation from grafts and recipient, the viral spread and
dissemination to different organs and apparatus, and potentially lethal outcome
Its moderately extended low-density halo and its accretion history
We present results based on Dark Energy Camera Legacy Survey (DECaLS) DR8 astrometric and photometric data sets of the Milky Way globular cluster Pal 13. Because of its relatively small size and mass, there is not yet a general consensus on the existence of extra-tidal structures surrounding it. While some previous results suggest the absence of such features, others show that the cluster is under the effects of tidal stripping. We have built a cluster stellar density map from DECaLS g, r magnitudes-previously corrected for interstellar reddening-of stars placed along the cluster main sequence in the color-magnitude diagram. The resulting density map shows nearly smooth contours around Pal 13 out to approximately 1.6 t the most recent estimate of its Jacobi radius, which was derived whilst taking into account the variation along its orbital motion. This outcome favors the presence of stars escaping the cluster, a phenomenon frequently seen in globular clusters that have crossed the Milky Way disk a comparably large number of times. Particularly, the orbital high eccentricity and large inclination angle of this accreted globular cluster could have been responsible for the relatively large amount of lost cluster mass.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Córdoba. Instituto de AstronomÃa Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de AstronomÃa Teórica y Experimental; ArgentinaFil: Fernández Trincado, José G.. Universidad de Atacama; Chil
Proximity Eliashberg theory of electrostatic field-effect-doping in superconducting films
We calculate the effect of a static electric field on the critical
temperature of a s-wave one band superconductor in the framework of proximity
effect Eliashberg theory. In the weak electrostatic field limit the theory has
no free parameters while, in general, the only free parameter is the thickness
of the surface layer where the electric field acts. We conclude that the best
situation for increasing the critical temperature is to have a very thin film
of a superconducting material with a strong increase of electron-phonon (boson)
constant upon charging.Comment: 9 pages, 5 figure
Old Age and Aerobic Microorganisms of Patients Affected by Clostridium difficile Infection are Associated Primarily with the Intestinal Presence of Clostridium difficile
Clostridium difficile infection in human occurs when the organism is present and germinating in the bowel. Old
age of patients\u2019 and particular microorganisms in stools are identified as risk factors for the disease onset. We aimed
to investigate if risk factors for C. difficile infections in a large Italian hospital were connected to C. difficile intestinal
presence or to germination. Toxin B positivity was linked with age over 65 years (P=0.03), medical hospitalization
(P=0.015) and growth of Enterobacteriaceae (P=0.029) and Enterococcus (P=0.05) from the same stools. The
presence of tcdB was even more strictly linked with old age (P=0.005), medicine hospitalization (P=0.012) and
growth of Enterobacteriaceae (P=0.003) and Enterococcus (P=0.04). Our results indicated that the presence of C.
difficile in stools, irrespective of being spore or vegetative form, is reliably associated with old age of subjects and
fecal presence of viable Enterobacteriaceae and Enterococcus
Age Determination of Fifteen Old to Intermediate-Age Small Magellanic Cloud Star Clusters
We present CMDs in the V and I bands for fifteen star clusters in the Small
Magellanic Cloud (SMC) based on data taken with the Very Large Telescope (VLT,
Chile). We selected these clusters from our previous work, wherein we derived
cluster radial velocities and metallicities from Calcium II infrared triplet
(CaT) spectra also taken with the VLT. We discovered that the ages of six of
our clusters have been appreciably underestimated by previous studies, which
used comparatively small telescopes, graphically illustrating the need for
large apertures to obtain reliable ages of old and intermediate-age SMC star
clusters. In particular, three of these clusters, L4, L6 and L110, turn out to
be amongst the oldest SMC clusters known, with ages of 7.9 +- 1.1, 8.7 +- 1.2
and 7.6 +- 1.0 Gyr, respectively, helping to fill a possible "SMC cluster age
gap" (Glatt et al. 2008). Using the present ages and metallicities from Parisi
et al. (2009), we analyze the age distribution, age gradient and age
metallicity relation (AMR) of a sample of SMC clusters measured homogeneously.
There is a suggestion of bimodality in the age distribution but it does not
show a constant slope for the first 4 Gyr (Piatti 2011), and we find no
evidence for an age gradient. Due to the improved ages of our cluster sample,
we find that our AMR is now better represented in the intermediate/old period
than that we derived in Parisi et al. (2009), where we simply took ages
available in the literature. Additionally, clusters younger than aprox. 4 Gyr
now show better agreement with the bursting model, but we confirm that this
model is not a good representation of the AMR during the intermediate-age/old
period. A more complicated model is needed to explain the SMC chemical
evolution in that period.Comment: 76 pages, 32 figures. Accepted for publication in A
Control of bulk superconductivity in a BCS superconductor by surface charge doping via electrochemical gating
The electrochemical gating technique is a powerful tool to tune the surface conduction properties
of various materials by means of pure charge doping, but its efficiency is thought to be hampered in
materials with a good electronic screening. We show that, if applied to a metallic superconductor
(NbN thin films), this approach allows observing reversible enhancements or suppressions of the bulk
superconducting transition temperature, which vary with the thickness of the films. These results
are interpreted in terms of proximity effect, and indicate that the effective screening length depends
on the induced charge density, becoming much larger than that predicted by standard screening
theory at very high electric fields
Comment on "A centrosome-independent role for gamma-TuRC proteins in the spindle assembly checkpoint"
Müller et al. (Reports, 27 October 2006, p. 654) showed that inhibition of the γ-tubulin ring complex (γ-TuRC) activates the spindle assembly checkpoint (SAC), which led them to suggest that γ-TuRC proteins play molecular roles in SAC activation. Because γ-TuRC inhibition leads to pleiotropic spindle defects, which are well known to activate kinetochore-derived checkpoint signaling, we believe that this conclusion is premature
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