493 research outputs found
Escaping death: Mitochondrial redox homeostasis in cancer cells
Reactive oxygen species (ROS) are important signaling molecules that act through the oxidation of nucleic acids, proteins, and lipids. Several hallmarks of cancer, including uncontrolled proliferation, angiogenesis, and genomic instability, are promoted by the increased ROS levels commonly found in tumor cells. To counteract excessive ROS accumulation, oxidative stress, and death, cancer cells tightly regulate ROS levels by enhancing scavenging enzymes, which are dependent on the reducing cofactor nicotinamide adenine dinucleotide phosphate (NADPH). This review focuses on mitochondrial ROS homeostasis with a description of six pathways of NADPH production in mitochondria and a discussion of the possible strategies of pharmacological intervention to selectively eliminate cancer cells by increasing their ROS levels
Enforced neutrality and color-flavor unlocking in the three-flavor Polyakov-loop NJL model
We study how the charge neutrality affects the phase structure of
three-flavor PNJL model. We point out that, within the conventional PNJL model
at finite density the color neutrality is missing because the Wilson line
serves as an external ``colored'' field coupled to dynamical quarks. In this
paper we heuristically assume that the model may still be applicable. To get
color neutrality one has then to allow non vanishing color chemical potentials.
We study how the quark matter phase diagram in -plane is
affected by imposing neutrality and by including the Polyakov loop dynamics.
Although these two effects are correlated in a nonlinear way, the impact of the
Polyakov loop turns out to be significant in the direction, while imposing
neutrality brings a remarkable effect in the direction. In
particular, we find a novel unlocking transition, when the temperature is
increased, even in the chiral SU(3) limit. We clarify how and why this is
possible once the dynamics of the colored Polyakov loop is taken into account.
Also we succeed in giving an analytic expression for for the transition
from two-flavor pairing (2SC) to unpaired quark matter in the presence of the
Polyakov loop.Comment: 11 pages, REVTex4, 10 eps figures; v2: added two notes, added a
reference; version to appear in Phys. Rev.
Cooling of a Compact Star with a LOFF Matter Core
Specific heat and neutrino emissivity due to direct URCA processes for quark
matter in the color superconductive Larkin-Ovchinnikov-Fulde-Ferrell (LOFF)
phase of Quantum-Chromodynamics have been evaluated. The cooling rate of
simplified models of compact stars with a LOFF matter core is estimated.Comment: 3 pages, 1 figure, to appear in the proceedings of the Helmoltz
International Summer School of Theoretical Physics on Dense Matter in Heavy
Ion Collisions and Astrophysics, JINR, Dubna, Russia, 21 Aug - 1 Sep 200
On the neutrality issue in the Polyakov-loop NJL model
We elucidate how the color neutrality is harmed in the Polyakov Nambu-Jona
Lasinio (PNJL) model at finite density within the adopted mean field
approximation. Also we point out how usual assumption about the diagonal form
of the Wilson loop may fail in the presence of the diquark condensate on
several grounds.Comment: 8 pages, 1 figure. Introduction enlarged, several comments about the
adopted mean field approximation and the relation with Elitzur's theorem
added. Version to appear on Phys. Rev.
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