11,377 research outputs found
Method for Identifying Regulators of Protein-Advanced Glycation End Product (Protein-Age) Formation
The invention relates to methods for identifying compounds which affect cellular stress. In particular, the method relates to identifying compounds which inhibit protein advanced glycation end product formation, where the compounds are carbonyl scavengers which inhibit the formation. The assay involves combing the substance of interest with histone H1 and ADP-ribose, and then measuring fluorescence and protein cross linking. Various inhibitors of protein AGE glycation have been identified, using this assay
Relativistic Acoustic Geometry
Sound wave propagation in a relativistic perfect fluid with a non-homogeneous
isentropic flow is studied in terms of acoustic geometry. The sound wave
equation turns out to be equivalent to the equation of motion for a massless
scalar field propagating in a curved space-time geometry. The geometry is
described by the acoustic metric tensor that depends locally on the equation of
state and the four-velocity of the fluid. For a relativistic supersonic flow in
curved space-time the ergosphere and acoustic horizon may be defined in a way
analogous the non-relativistic case. A general-relativistic expression for the
acoustic analog of surface gravity has been found.Comment: 14 pages, LaTe
Large-N bounds on, and compositeness limit of, gauge and gravitational interactions
In a toy model of gauge and gravitational interactions in
dimensions, endowed with an invariant UV cut-off , and containing a
large number of non-self-interacting matter species, the physical gauge and
gravitational couplings at the cut-off, and
, are shown to be bounded by appropriate
powers of . This implies that the infinite-bare-coupling (so-called
compositeness) limit of these theories is smooth, and can even resemble our
world. We argue that such a result, when extended to more realistic situations,
can help avoid large-N violations of entropy bounds, solve the dilaton
stabilization and GUT-scale problems in superstring theory, and provide a new
possible candidate for quintessence.Comment: 8 pages, Latex, minor modifications in notations and reference
Method and Use of α-Amino-ÎČ-Mercapto-Ethane Derivatives as Dicarbonyl Scavengers for Treatment of Conditions Resulting from Protein, Lipid, and DNA Damage
Methods of inhibiting damage to proteins, lipids, and DNA by the use of penicillamines and other α-amino-ÎČ,ÎČ-mercapto-ÎČ,ÎČ-dimethyl-ethane compounds as dicarbonyl scavengers is disclosed
Black hole entropy: inside or out?
A trialogue. Ted, Don, and Carlo consider the nature of black hole entropy.
Ted and Carlo support the idea that this entropy measures in some sense ``the
number of black hole microstates that can communicate with the outside world.''
Don is critical of this approach, and discussion ensues, focusing on the
question of whether the first law of black hole thermodynamics can be
understood from a statistical mechanics point of view.Comment: 42 pages, contribution to proceedings of Peyresq
Threshold configurations in the presence of Lorentz violating dispersion relations
A general characterization of lower and upper threshold configurations for
two particle reactions is determined under the assumptions that the single
particle dispersion relations E(p) are rotationally invariant and monotonic in
p, and that energy and momentum are conserved and additive for multiple
particles. It is found that at a threshold the final particle momenta are
always parallel and the initial momenta are always anti-parallel. The
occurrence of new phenomena not occurring in a Lorentz invariant setting, such
as upper thresholds and asymmetric pair production thresholds, is explained,
and an illustrative example is given.Comment: 5 pages, 3 figure
Resonance NLS Solitons as Black Holes in Madelung Fluid
A new resonance version of NLS equation is found and embedded to the
reaction-diffusion system, equivalent to the anti-de Sitter valued Heisenberg
model, realizing a particular gauge fixing condition of the Jackiw-Teitelboim
gravity. The space-time points where dispersion change the sign correspond to
the event horizon, and the soliton solutions to the AdS black holes. The
soliton with velocity bounded above describes evolution on the hyperboloid with
nontrivial winding number and create under collisions the resonance states with
a specific life time.Comment: Plain Tex, 12 pages, 6 figure
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
Stochastically Fluctuating Black-Hole Geometry, Hawking Radiation and the Trans-Planckian Problem
We study the propagation of null rays and massless fields in a black hole
fluctuating geometry. The metric fluctuations are induced by a small
oscillating incoming flux of energy. The flux also induces black hole mass
oscillations around its average value. We assume that the metric fluctuations
are described by a statistical ensemble. The stochastic variables are the
phases and the amplitudes of Fourier modes of the fluctuations. By averaging
over these variables, we obtain an effective propagation for massless fields
which is characterized by a critical length defined by the amplitude of the
metric fluctuations: Smooth wave packets with respect to this length are not
significantly affected when they are propagated forward in time. Concomitantly,
we find that the asymptotic properties of Hawking radiation are not severely
modified. However, backward propagated wave packets are dissipated by the
metric fluctuations once their blue shifted frequency reaches the inverse
critical length. All these properties bear many resemblences with those
obtained in models for black hole radiation based on a modified dispersion
relation. This strongly suggests that the physical origin of these models,
which were introduced to confront the trans-Planckian problem, comes from the
fluctuations of the black hole geometry.Comment: 32 page
Model of black hole evolution
From the postulate that a black hole can be replaced by a boundary on the
apparent horizon with suitable boundary conditions, an unconventional scenario
for the evolution emerges. Only an insignificant fraction of energy of order
is radiated out. The outgoing wave carries a very small part of the
quantum mechanical information of the collapsed body, the bulk of the
information remaining in the final stable black hole geometry.Comment: 9 pages, harvmac, 3 figures, minor addition
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