8 research outputs found
A piece of cake: the ground-state energies in gamma_i-deformed N=4 SYM theory
In the non-supersymmetric gamma_i-deformed N=4 SYM theory, the scaling
dimensions of the operators tr[Z^L] composed of L scalar fields Z receive
finite-size wrapping and prewrapping corrections in the 't Hooft limit. In this
paper, we calculate these scaling dimensions to leading wrapping order directly
from Feynman diagrams. For L>=3, the result is proportional to the maximally
transcendental `cake' integral. It matches with an earlier result obtained from
the integrability-based Luescher corrections, TBA and Y-system equations. At
L=2, where the integrability-based equations yield infinity, we find a finite
rational result. This result is renormalization-scheme dependent due to the
non-vanishing beta-function of an induced quartic scalar double-trace coupling,
on which we have reported earlier. This explicitly shows that conformal
invariance is broken - even in the 't Hooft limit.Comment: 21 pages, LaTeX, BibTeX, pstricks, feynm
The complete one-loop dilatation operator of planar real beta-deformed N=4 SYM theory
We determine the missing finite-size corrections to the asymptotic one-loop
dilatation operator of the real -deformed SYM theory for
the gauge groups and in the 't Hooft limit. In the case,
the absence of the field components leads to a new kind of finite-size
effect, which we call prewrapping. We classify which states are potentially
affected by prewrapping at generic loop orders and comment on the necessity to
include it into the integrability-based description. As a further result, we
identify classes of -point correlation functions which at all loop orders in
the planar theory are given by the values of their undeformed counterparts.
Finally, we determine the superconformal multiplet structure and one-loop
anomalous dimensions of all single-trace states with classical scaling
dimension .Comment: Latex, feynmp, pstricks, 37 pages, 6 tables, v2: formulations
improved, references added, typos corrected, v3: typos corrected, matches
published versio
TNF-α Induces Macroautophagy and Regulates MHC Class II Expression in Human Skeletal Muscle Cells*
Macroautophagy, a homeostatic process that shuttles cytoplasmic constituents into endosomal and lysosomal compartments, has recently been shown to deliver antigens for presentation on major histocompatibility complex (MHC) class II molecules. Skeletal muscle fibers show a high level of constitutive macroautophagy and express MHC class II molecules upon immune activation. We found that tumor necrosis factor-α (TNF-α), a monokine overexpressed in inflammatory myopathies, led to a marked up-regulation of macroautophagy in skeletal myocytes. Furthermore, TNF-α augmented surface expression of MHC class II molecules in interferon-γ (IFN-γ)-treated myoblasts. The synergistic effect of TNF-α and IFN-γ on the induction of MHC class II surface expression was not reflected by higher intracellular human leukocyte antigen (HLA)-DR levels and was reversed by macroautophagy inhibition, suggesting that TNF-α facilitates antigen processing via macroautophagy for more efficient MHC class II loading. Muscle biopsies from patients with sporadic inclusion body myositis, a well defined myopathy with chronic inflammation, showed that over 20% of fibers that contained autophagosomes costained for MHC class II molecules and that more than 40% of double-positive muscle fibers had contact with CD4+ and CD8+ immune cells. These findings establish a mechanism through which TNF-α regulates both macroautophagy and MHC class II expression and suggest that macroautophagy-mediated antigen presentation contributes to the immunological environment of the inflamed human skeletal muscle