1,854 research outputs found
Modelling background charge rearrangements near single-electron transistors as a Poisson process
Background charge rearrangements in metallic single-electron transistors are
modelled in two-level tunnelling systems as a Poisson process with a scale
parameter as only variable. The model explains the recent observation of
asymmetric Coulomb blockade peak spacing distributions in metallic
single-electron transistors. From the scale parameter we estimate the average
size of the tunnelling systems, their density of states, and the height of
their energy barrier. We conclude that the observed background charge
rearrangements predominantly take place in the substrate of the single-electron
transistor.Comment: 7 pages, 2 eps figures, used epl.cls macro include
Caspase-independent programmed cell death triggers Ca2PO4 deposition in an in vitro model of nephrocalcinosis
We provide evidence of caspase-independent cell death triggering the calcification process in GDNF-silenced HK-2 cells
Indecomposable U_q(sl_n) modules for q^h = -1 and BRS intertwiners
A class of indecomposable representations of U_q(sl_n) is considered for q an even root of unity (q^h = -1) exhibiting a similar structure as (height h) indecomposable lowest weight Kac-Moody modules associated with a chiral conformal field theory. In particular, U_q(sl_n) counterparts of the Bernard-Felder BRS operators are constructed for n=2,3. For n=2 a pair of dual d_2(h) = h dimensional U_q(sl_2) modules gives rise to a 2h-dimensional indecomposable representation including those studied earlier in the context of tensor product expansions of irreducible representations. For n=3 the interplay between the Poincare'-Birkhoff-Witt and (Lusztig) canonical bases is exploited in the study of d_3(h) = h(h+1)(2h+1)/6 dimensional indecomposable modules and of the corresponding intertwiners
Quantum matrix algebra for the SU(n) WZNW model
The zero modes of the chiral SU(n) WZNW model give rise to an intertwining
quantum matrix algebra A generated by an n x n matrix a=(a^i_\alpha) (with
noncommuting entries) and by rational functions of n commuting elements
q^{p_i}. We study a generalization of the Fock space (F) representation of A
for generic q (q not a root of unity) and demonstrate that it gives rise to a
model of the quantum universal enveloping algebra U_q(sl_n), each irreducible
representation entering F with multiplicity 1. For an integer level k the
complex parameter q is an even root of unity, q^h=-1 (h=k+n) and the algebra A
has an ideal I_h such that the factor algebra A_h = A/I_h is finite
dimensional.Comment: 48 pages, LaTeX, uses amsfonts; final version to appear in J. Phys.
Indecomposable U_q(sl_n) modules for q^h = -1 and BRS intertwiners
A class of indecomposable representations of U_q(sl_n) is considered for q an
even root of unity (q^h = -1) exhibiting a similar structure as (height h)
indecomposable lowest weight Kac-Moody modules associated with a chiral
conformal field theory. In particular, U_q(sl_n) counterparts of the
Bernard-Felder BRS operators are constructed for n=2,3. For n=2 a pair of dual
d_2(h) = h dimensional U_q(sl_2) modules gives rise to a 2h-dimensional
indecomposable representation including those studied earlier in the context of
tensor product expansions of irreducible representations. For n=3 the interplay
between the Poincare'-Birkhoff-Witt and (Lusztig) canonical bases is exploited
in the study of d_3(h) = h(h+1)(2h+1)/6 dimensional indecomposable modules and
of the corresponding intertwiners.Comment: 31 pages, LaTeX, amsfonts, amssym
Characters of fusion algebra at non-rational level
We construct the fusion ring of a quasi-rational WZNW theory
at generic level . It is generated by commutative elements in the
group ring of the affine Weyl group which extend
polynomially the formal characters of finite dimensional representations of
.Comment: 10 pages, harvmac.te
IL4 induces IL6-producing M2 macrophages associated to inhibition of neuroinflammation in vitro and in vivo
Background: Myeloid cells, such as macrophages and microglia, play a crucial role in neuroinflammation and have been recently identified as a novel therapeutic target, especially for chronic forms. The general aim would be to change the phenotype of myeloid cells from pro- to anti-inflammatory, favoring their tissue-trophic and regenerative functions. Myeloid cells, however, display a number of functional phenotypes, not immediately identifiable as pro- or anti-inflammatory, and associated to ambiguous markers. Methods: We employed in vitro assays to study macrophage polarization/differentiation in the presence of classical polarizing stimuli such as IFNγ (pro-inflammatory) and IL4 (anti-inflammatory). We induced neuroinflammation in mice by immunization with a myelin antigen and treated diseased mice with intracisternal delivery of an IL4-expressing lentiviral vector. We analyzed clinical, pathological, and immunological outcomes with a focus on myeloid cells. Results: We found that IL6, usually considered a pro-inflammatory cytokine, was released in vitro by macrophages treated with the anti-inflammatory cytokine IL4. We show the existence of macrophages expressing IL6 along with classical anti-inflammatory markers such as CD206 and demonstrate that these cells are immunosuppressive in vitro. In neuroinflamed mice, we show that IL4 delivery in the central nervous system (CNS) is associated with clinical and pathological protection from disease, associated with increased IL6 expression in infiltrating macrophages. Conclusions: IL6 is known to mediate both pro- and anti-inflammatory effects, having two distinct ways to induce cell-signaling: either through the membrane bound receptor (anti-inflammatory) or through trans-signaling (pro-inflammatory). We show here that IL6-expressing macrophages are associated to protection from neuroinflammation, suggesting that IL6 anti-inflammatory properties prevail in the CNS, and calling for a general reconsideration of IL6 in macrophage polarization
Noise reduction in muon tomography for detecting high density objects
The muon tomography technique, based on multiple Coulomb scattering of cosmic
ray muons, has been proposed as a tool to detect the presence of high density
objects inside closed volumes. In this paper a new and innovative method is
presented to handle the density fluctuations (noise) of reconstructed images, a
well known problem of this technique. The effectiveness of our method is
evaluated using experimental data obtained with a muon tomography prototype
located at the Legnaro National Laboratories (LNL) of the Istituto Nazionale di
Fisica Nucleare (INFN). The results reported in this paper, obtained with real
cosmic ray data, show that with appropriate image filtering and muon momentum
classification, the muon tomography technique can detect high density
materials, such as lead, albeit surrounded by light or medium density material,
in short times. A comparison with algorithms published in literature is also
presented
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