101 research outputs found
Ocular experimental leishmaniasis in C57BL/10 and BALB/c mice induced by Leishmania amazonensis infection
AbstractThere are few studies on human ocular leishmaniasis found in the literature. The purpose of this study was to describe experimental ocular leishmaniasis, caused by Leishmania amazonensis evaluating two different infection routes: intravitreal and instillation in C57BL/10 and BALB/c mice. In this work all animals presented low anti-Leishmania IgM and IgG titers regardless of the infection route or mouse strain. The histopathological eye analysis showed that the mice inoculated by the intravitreal route developed more severe lesions, presenting parasites in the anterior region of the eye 60days after infection. The C57BL/10 mice presented cells containing parasitophorous vacuoles associated with pigmented cells and inflammatory infiltrate, which included mast cells. Ninety days after infection no parasites could be found in either mouse strain, which led us to hypothesize that parasites had been eliminated. In this context, we show that both intravitreal and instillation routes were effective in promoting ocular leishmaniasis infections in C57BL/10 and BALB/c mice. There were no differences in the parasite infection between the two mouse models and it mimicked the ocular lesions described in symptomatic dogs in endemic areas of visceral leishmaniasis
Inflation Physics from the Cosmic Microwave Background and Large Scale Structure
Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of CMB and large-scale structure (LSS) experiments are poised to test the leading paradigm for these earliest moments---the theory of cosmic inflation---and to detect the imprints of the inflationary epoch, thereby dramatically increasing our understanding of fundamental physics and the early universe. A future CMB experiment with sufficient angular resolution and frequency coverage that surveys at least 1 of the sky to a depth of 1 uK-arcmin can deliver a constraint on the tensor-to-scalar ratio that will either result in a 5-sigma measurement of the energy scale of inflation or rule out all large-field inflation models, even in the presence of foregrounds and the gravitational lensing B-mode signal. LSS experiments, particularly spectroscopic surveys such as the Dark Energy Spectroscopic Instrument, will complement the CMB effort by improving current constraints on running of the spectral index by up to a factor of four, improving constraints on curvature by a factor of ten, and providing non-Gaussianity constraints that are competitive with the current CMB bounds
A search for the decay
We search for the rare flavor-changing neutral-current decay in a data sample of 82 fb collected with the {\sl BABAR}
detector at the PEP-II B-factory. Signal events are selected by examining the
properties of the system recoiling against either a reconstructed hadronic or
semileptonic charged-B decay. Using these two independent samples we obtain a
combined limit of
at the 90% confidence level. In addition, by selecting for pions rather than
kaons, we obtain a limit of using only the hadronic B reconstruction method.Comment: 7 pages, 8 postscript figures, submitted to Phys. Rev. Let
High-reflectivity broadband distributed Bragg reflector lattice matched to ZnTe
We report on the realization of a high quality distributed Bragg reflector
with both high and low refractive index layers lattice matched to ZnTe. Our
structure is grown by molecular beam epitaxy and is based on binary compounds
only. The high refractive index layer is made of ZnTe, while the low index
material is made of a short period triple superlattice containing MgSe, MgTe,
and ZnTe. The high refractive index step of Delta_n=0.5 in the structure
results in a broad stopband and the reflectivity coefficient exceeding 99% for
only 15 Bragg pairs.Comment: 4 pages, 3 figure
EuFeAs under high pressure: an antiferromagnetic bulk superconductor
We report the ac magnetic susceptibility and resistivity
measurements of EuFeAs under high pressure . By observing nearly
100% superconducting shielding and zero resistivity at = 28 kbar, we
establish that -induced superconductivity occurs at ~30 K in
EuFeAs. shows an anomalous nearly linear temperature dependence
from room temperature down to at the same . indicates that
an antiferromagnetic order of Eu moments with ~20 K persists
in the superconducting phase. The temperature dependence of the upper critical
field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.
Improved measurement of CP asymmetries in B-0 ->(c(c)over-bar)K0((*)) decays
We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 227x10(6) Upsilon(4S)-> B (B) over bar decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The amplitude of the CPasymmetry, sin2 beta in the standard model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B-0 or (0) from its decay products. We measure sin2 beta=0.722 +/- 0.040(stat)+/- 0.023(syst) in agreement with the standard model expectation
Highly-parallelized simulation of a pixelated LArTPC on a GPU
The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype
Trypanosoma cruzi infection patterns in intact and athymic mice of susceptible and resistant genotypes
Inbred strains of mice inoculated with the T.
cruzi Y strain behaved as susceptible (A/J, C3H/HeN),
intermediate (BALB/c) or relatively resistant (C57BL/6)
with respect to the magnitude of parasitaemia and
mortality rate. C57BL/10 mice were susceptible in
relation to parasitaemia but resistant when mortality was
analyzed. Infection with T. cruzi CL strain presented the
same results, except for C57BL/6 which behaved as
susceptible mice. Athymic mice of various backgrounds
revealed no differences in susceptibility, presenting the
same dramatic parasitaemia, tissue colonization pattern
and no inflammatory reaction in any of the tissues
studied. Infection of euthymic and athymic BALB/c
mice elicited the production of parasite-specific
antibodies, which reached similar levels on the first 9
days but differed after day 13. Serum transfer
experiments in BALB/c mice did not show great
differences in parasitaemia but altered T. cruzi
polymorphism reducing the slender forms in athymic
mice. Histopathology of athymic BALB/c mice showed
the same tissue tropism when infected either with T.
cruzi Y or CL strain
Biological behavior of Leishmania (L.) amazonensis isolated from a human diffuse cutaneous leishmaniasis in inbred strains of mice
After a subcutaneous injection of 104
purified amastigotes of an isolate from a diffuse case of
cutaneous leishmaniasis caused by the
MHOM/BR/76/Ma-5 strain of Leishmania amazonensis,
three inbred mouse strains developed a progressive
nodular lesion, which evolved to an ulcerated lesion.
Based on these data, mice of BALB/c, C57BL/6 or
C57BL/10 could be classified as susceptible. The
majority of mice developed metastases in the footpads,
ear, tail, nose and oral mucosa. Amputation of the
members related to the primary lesion was frequent.
Experiments using the limiting dilution analysis showed
that there was no correlation between lesion and parasite
load. It has been demonstrated that these mouse strains
could be considered excellent models for mucocutaneous
leishmaniasis when infected with L. amazonensis.
Metastatic lesions caused destruction of the nasal
region with many parasitized macrophages under the
epithelial surface of the nasal mucosa. Bone destruction
occurred with an extensive inflammatory reaction
presenting macrophages heavily parasitized by
amastigotes. The parasites also spread to the periodontal
ligament and other structures of the oral cavity, which
could induce a severe inflammatory process. This study
indicates that both nasal and oral lesions in mice infected
by L. amazonensis were characterized by an
inflammatory reaction with the presence of a high
parasite load within macrophages
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