1,102 research outputs found
Transmissible spongiform encephalopathies: molecular biology, diagnosis and therapeutic approaches
Las encefalopatías espongiformes transmisibles constituyen un grupo de enfermedades neurodegenerativas que están
asociadas a la presencia en el tejido nervioso de agregados insolubles constituidos por una isoforma anómala de una
proteína denominada prión. Esta isoforma se produce por un cambio conformacional en una molécula que puede
transmitirse a otras proteínas priónicas normales. Las proteínas modificadas pierden su actividad biológica, desencadenándose
la muerte de las neuronas por apoptosis. Los cambios conformacionales de los priones que derivan en
enfermedad pueden deberse a la existencia de mutaciones que disminuyan la estabilidad de las formas celulares.
Existe susceptibilidad genética, por tanto, a padecer tipos hereditarios de la enfermedad o adquiridos por infección
con isoformas priónicas anormales. En la actualidad se están perfeccionando métodos sensibles de diagnóstico
basados en la detección de las isoformas anormales de la proteína priónica. Todavía no existen tratamientos curativos
para estas enfermedades aunque se están diseñando métodos terapéuticos que bloqueen los cambios conformacionales
que conducen a la precipitación de la proteína priónica.Transmissible spongiform encephalopaties constitute a group of neurodegenerative diseases associated to the presence
in nervous tissue of insoluble aggregates originated by an anomalous isoform of a protein called prion. This isoform
is produced by a conformational change in a molecule which is transmitted to normal prion proteins. Modified proteins
loose their biological activity, provoking apoptotic death of neurons. Conformational changes of prions occasioning the
illness can be due to the existence of mutations diminishing the stability of cellular forms. There is genetic susceptibility
for suffering any type of the illness, either hereditary or acquired by infection with abnormal prion isoforms. New
sensitive diagnostic methods are presently being developed, based on detection of abnormal isoforms of prion protein.
There are no curative treatments for these illnesses, although new therapeutic strategies based on the blockage of
conformational changes driving to protein precipitation are being designed
Role of magnetic anisotropy on the magnetic properties of Ni nanoclusters embedded in a ZnO matrix
We have investigated the magnetic properties of Ni nanoaggregates produced by ion implantation in ZnO single crystals. Several deviations from classical models usually adopted to describe the magnetic properties of nanoparticle systems were found. The strain between host and Ni nanoaggregates induces a magnetic anisotropy with a preferred direction. We show that these anisotropy effects can be misinterpreted as a ferromagnetic or antiferromagnetic coupling among the nanoaggregates similar to that of an oriented, interacting nanocrystal ensemble
Quantum states and specific heat of low-density He gas adsorbed within the carbon nanotube interstitial channels: Band structure effects and potential dependence
We calculate the energy-band structure of a He atom trapped within the
interstitial channel between close-packed nanotubes within a bundle and its
influence on the specific heat of the adsorbed gas. A robust prediction of our
calculations is that the contribution of the low-density adsorbed gas to the
specific heat of the nanotube material shows pronounced nonmonotonic variations
with temperature. These variations are shown to be closely related to the band
gaps in the adsorbate density of states
Catalase activity in Smicridea McLachlan, 1871 (Insecta, Trichoptera) collected from natural and altered/impacted streams
Phylogenetic and pathotype analysis of Escherichia coli swine isolates from Southern Brazil
Significant mortality of eggs and young larvae of two pine processionary moth species due to the entomopathogenic fungus Metarhizium brunneum
Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at TeV
The elliptic, , triangular, , and quadrangular, , azimuthal
anisotropic flow coefficients are measured for unidentified charged particles,
pions and (anti-)protons in Pb-Pb collisions at TeV
with the ALICE detector at the Large Hadron Collider. Results obtained with the
event plane and four-particle cumulant methods are reported for the
pseudo-rapidity range at different collision centralities and as a
function of transverse momentum, , out to GeV/.
The observed non-zero elliptic and triangular flow depends only weakly on
transverse momentum for GeV/. The small dependence
of the difference between elliptic flow results obtained from the event plane
and four-particle cumulant methods suggests a common origin of flow
fluctuations up to GeV/. The magnitude of the (anti-)proton
elliptic and triangular flow is larger than that of pions out to at least
GeV/ indicating that the particle type dependence persists out
to high .Comment: 16 pages, 5 captioned figures, authors from page 11, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
Centrality dependence of charged particle production at large transverse momentum in Pb-Pb collisions at TeV
The inclusive transverse momentum () distributions of primary
charged particles are measured in the pseudo-rapidity range as a
function of event centrality in Pb-Pb collisions at
TeV with ALICE at the LHC. The data are presented in the range
GeV/ for nine centrality intervals from 70-80% to 0-5%.
The Pb-Pb spectra are presented in terms of the nuclear modification factor
using a pp reference spectrum measured at the same collision
energy. We observe that the suppression of high- particles strongly
depends on event centrality. In central collisions (0-5%) the yield is most
suppressed with at -7 GeV/. Above
GeV/, there is a significant rise in the nuclear modification
factor, which reaches for GeV/. In
peripheral collisions (70-80%), the suppression is weaker with almost independently of . The measured nuclear
modification factors are compared to other measurements and model calculations.Comment: 17 pages, 4 captioned figures, 2 tables, authors from page 12,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/284
Measurement of charm production at central rapidity in proton-proton collisions at TeV
The -differential production cross sections of the prompt (B
feed-down subtracted) charmed mesons D, D, and D in the rapidity
range , and for transverse momentum GeV/, were
measured in proton-proton collisions at TeV with the ALICE
detector at the Large Hadron Collider. The analysis exploited the hadronic
decays DK, DK, DD, and their charge conjugates, and was performed on a
nb event sample collected in 2011 with a
minimum-bias trigger. The total charm production cross section at TeV and at 7 TeV was evaluated by extrapolating to the full phase space
the -differential production cross sections at TeV
and our previous measurements at TeV. The results were compared
to existing measurements and to perturbative-QCD calculations. The fraction of
cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/307
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