2,693 research outputs found
Blood manufacturing methods affect red blood cell product characteristics and immunomodulatory activity
Transfusion of red cell concentrates (RCCs) is associated with increased risk of adverse outcomes that may be affected by different blood manufacturing methods and the presence of extracellular vesicles (EVs). We investigated the effect of different manufacturing methods on hemolysis, residual cells, cell-derived EVs, and immunomodulatory effects on monocyte activity. Thirty-two RCC units produced using whole blood filtration (WBF), red cell filtration (RCF), apheresis-derived (AD), and whole blood-derived (WBD) methods were examined (n = 8 per method). Residual platelet and white blood cells (WBCs) and the concentration, cell of origin, and characterization of EVs in RCC supernatants were assessed in fresh and stored supernatants. Immunomodulatory activity of RCC supernatants was assessed by quantifying monocyte cytokine production capacity in an in vitro transfusion model. RCF units yielded the lowest number of platelet and WBC-derived EVs, whereas the highest number of platelet EVs was in AD (day 5) and in WBD (day 42). The number of small EVs (<200 nm) was greater than large EVs (≥200 nm) in all tested supernatants, and the highest level of small EVs were in AD units. Immunomodulatory activity was mixed, with evidence of both inflammatory and immunosuppressive effects. Monocytes produced more inflammatory interleukin-8 after exposure to fresh WBF or expired WBD supernatants. Exposure to supernatants from AD and WBD RCC suppressed monocyte lipopolysaccharide-induced cytokine production. Manufacturing methods significantly affect RCC unit EV characteristics and are associated with an immunomodulatory effect of RCC supernatants, which may affect the quality and safety of RCCs
Discovery of a [WO] central star in the planetary nebula Th 2-A
% context About 2500 planetary nebulae are known in our Galaxy but only 224
have central stars with reported spectral types in the Strasbourg-ESO Catalogue
of Galactic Planetary Nebulae (Acker et al. 1992; Acker et al. 1996) % aims We
have started an observational program aiming to increase the number of PN
central stars with spectral classification. % methods By means of spectroscopy
and high resolution imaging, we identify the position and true nature of the
central star. We carried out low resolution spectroscopic observations at
CASLEO telescope, complemented with medium resolution spectroscopy performed at
Gemini South and Magellan telescopes. % results As a first outcome of this
survey, we present for the first time the spectra of the central star of the PN
Th 2-A. These spectra show emission lines of ionized C and O, typical in
Wolf-Rayet stars. % conclusions We identify the position of that central star,
which is not the brightest one of the visual central pair. We classify it as of
type [WO 3]pec, which is consistent with the high excitation and dynamical age
of the nebula.Comment: 3 pages and 2 figures. Paper recommended for publication in A&
K_L \ra \mu^\pm e^\mp \nu \overline{\nu} as background to K_L \ra \mu^\pm e^\mp
We consider the process K_L \ra \mu^\pm e^\mp \nu \overline{\nu} at next to
leading order in chiral perturbation theory. This process occurs in the
standard model at second order in the weak interaction and constitutes a
potential background in searches for new physics through the modes K_L \ra
\mu^\pm e^\mp. We find that the same cut, ~MeV, used to remove
the sequential decays K_{l3}\ra \pi_{l2} pushes the B(K_L \ra \mu^\pm e^\mp
\nu \overline{\nu}) to the level, effectively removing it as a
background.Comment: 8 pages, LaTeX, 1 figure appended as postscript file after
\end{document}. Fermilab-Pub-93/024-
Effects for atmospheric neutrino experiments from electron neutrino oscillations
The minimal interpretation of the atmospheric neutrino data suggests that the
muon neutrino oscillates into another species with a mixing angle close to the
maximal . In the Exact Parity Symmetric Model, both the muon and
electron neutrinos are expected to be maximally mixed with essentially sterile
partners ( and respectively). We examine the impact of
maximal oscillations on the atmospheric neutrino experiments.
We estimate that maximal oscillations will have effects on
atmospheric neutrino data for . For in this range, a slight but distinctive rise in the
ratio of muon-like to electron-like events is predicted for the low-energy
sample. Furthermore, the ratio of low-energy electron-like events with zenith
angles less than to those with zenith angles greater than
should be greater than 1.Comment: 11 pages, LaTeX, no figure
The true nature of the alleged planetary nebula W16-185
We report the discovery of a small cluster of massive stars embedded in a NIR
nebula in the direction of the IRAS15411-5352 point source, which is related to
the alleged planetary nebula W16-185. The majority of the stars present large
NIR excess characteristic of young stellar objects and have bright counterparts
in the Spitzer IRAC images; the most luminous star (IRS1) is the NIR
counterpart of the IRAS source. We found very strong unresolved Brgamma
emission at the IRS1 position and more diluted and extended emission across the
continuum nebula. From the sizes and electron volume densities we concluded
that they represent ultra-compact and compact HII regions, respectively.
Comparing the Brgamma emission with the 7 mm free-free emission, we estimated
that the visual extinction ranges between 14 and 20 mag. We found that only one
star (IRS1) can provide the number of UV photons necessary to ionize the
nebula.Comment: 30 pages, 15 figures, 2 tables V3: minor grammatical changes. Figure
4 is available in pdf file. Accepted for publication in AJ, April / 200
Neutrino Lasing in the Sun
Applying the phenomenon of neutrino lasing in the solar interior, we show how
the rate for the generic neutrino decay process `\nu -> fermion + boson', can
in principal be enhanced by many orders of magnitude over its normal decay
rate. Such a large enhancement could be of import to neutrino-decay models
invoked in response to the apparent deficit of electron neutrinos observed from
the sun. The significance of this result to such models depends on the specific
form of the neutrino decay, and the particle model within which it is embedded.Comment: 12 pages, using ordinary TeX. No figure
An Investigation of Equivalence Principle Violations Using Solar Neutrino Oscillations in a Constant Gravitational Potential
Neutrino oscillations induced by a flavor-dependent violation of the Einstein
Equivalence Principle (VEP) have been recently considered as a suitable
explanation of the solar electron-neutrino deficiency. Unlike the MSW
oscillation mechanism, the VEP mechanism is dependent on a coupling to the
local background gravitational potential . We investigate the differences
which arise by considering three-flavor VEP neutrinos oscillating against fixed
background potentials, and against the radially-dependent solar potential. This
can help determine the sensitivity of the gravitationally-induced oscillations
to both constancy and size (order of magnitude) of . In particular, we
consider the potential of the local superculster, , in
light of recent work suggesting that the varying solar potential has no effect
on the oscillations. The possibility for arbitrarily large background
potentials in different cosmologies is discussed, and the effects of one such
potential () are considered.Comment: 12pp, LaTeX; 12 figures (bitmapped postscript); Submitted to Phys Rev
MSW mediated neutrino decay and the solar neutrino problem
We investigate the solar neutrino problem assuming simultaneous presence of
MSW transitions in the sun and neutrino decay on the way from sun to earth. We
do a global -analysis of the data on total rates in Cl, Ga and
Superkamiokande (SK) experiments and the SK day-night spectrum data and
determine the changes in the allowed region in the \dm - \tan^2\theta plane
in presence of decay. We also discuss the implications for unstable neutrinos
in the SNO experiment.Comment: Final version to appear in Phys. Rev.
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