2,340 research outputs found
Extremal Charged Rotating Dilaton Black Holes in Odd Dimensions
Employing higher order perturbation theory, we find a new class of charged
rotating black hole solutions of Einstein-Maxwell-dilaton theory with general
dilaton coupling constant. Starting from the Myers-Perry solutions, we use the
electric charge as the perturbative parameter, and focus on extremal black
holes with equal-magnitude angular momenta in odd dimensions. We perform the
perturbations up to 4th order for black holes in 5 dimensions and up to 3rd
order in higher odd dimensions. We calculate the physical properties of these
black holes and study their dependence on the charge and the dilaton coupling
constant.Comment: 20 pages, 3 figure
Symmetry-enhanced supertransfer of delocalized quantum states
Coherent hopping of excitation rely on quantum coherence over physically
extended states. In this work, we consider simple models to examine the effect
of symmetries of delocalized multi-excitation states on the dynamical
timescales, including hopping rates, radiative decay, and environmental
interactions. While the decoherence (pure dephasing) rate of an extended state
over N sites is comparable to that of a non-extended state, superradiance leads
to a factor of N enhancement in decay and absorption rates. In addition to
superradiance, we illustrate how the multi-excitonic states exhibit
`supertransfer' in the far-field regime: hopping from a symmetrized state over
N sites to a symmetrized state over M sites at a rate proportional to MN. We
argue that such symmetries could play an operational role in physical systems
based on the competition between symmetry-enhanced interactions and localized
inhomogeneities and environmental interactions that destroy symmetry. As an
example, we propose that supertransfer and coherent hopping play a role in
recent observations of anomolously long diffusion lengths in nano-engineered
assembly of light-harvesting complexes.Comment: 6 page
Morphological instability of the solid-liquid interface in crystal growth under supercooled liquid film flow and natural convection airflow
Ring-like ripples on the surface of icicles are an example of morphological
instability of the ice-water interface during ice growth under supercooled
water film flow. The surface of icicles is typically covered with ripples of
about 1 cm in wavelength, and the wavelength appears to be almost independent
of external temperature, icicle radius, and volumetric water flow rate. One
side of the water layer consists of the water-air surface and growing ice is
the other. This is one of the more complicated moving phase boundary problems
with two interfaces. A recent theoretical work [K. Ueno, Phys. Rev. E 68,
(2003) 021603] to address the underlying instability that produces ripples is
based on the assumption of the absence of airflow around icicles. In this
paper, we extend the previous theoretical framework to include a natural
convection airflow ahead of the water-air surface and consider whether the
effect of natural convection airflow on the wavelength of ripples produced on
an ice surface is essential or not.Comment: 19 pages, 5 figure
Differentiation of mesenchymal stem cells into hepatocytes
Acute and chronic liver diseases are common in Kazakhstan and other countries. These
diseases are known to cause significant disability and death. In many cases, liver transplantation is the
last resort for patients with end stage liver disease, but it is an extremely expensive procedure and is
associated with many risks. The most important among them is an immune rejection. Autologous cell
transplantation is a potential therapeutic approach for liver regeneration and could become an alternative
to organ transplantation. In this regard, mesenchymal stem cells (MSCs) are a very attractive source for
differentiation into hepatocytes. These cells can be isolated from bone marrow and adipose tissue of the
patient and exponentially expanded in vitro. Transplantation of hepatocytes differentiated from MSCs
could become a new promising approach in treatment of the patients with chronic liver conditions
Immunomodulatory effects of human umbilical cord wharton's Jelly-Derived mesenchymal stem cells on differentiation, maturation and endocytosis of monocyte-derived dendritic cells
The Wharton's jelly of the umbilical cord is believed to be a source of mesenchymal stem cells (MSCs) which can be therapeutically applied in degenerative diseases. In this study, we investigated the immunomodulatory effect of umbilical cord derivedmesenchymal stem cells (UC-MSCs) and bone marrow-derived-mesenchymal stem cells (BM-MSCs) on differentiation, maturation, and endocytosis of monocyte-derived dendritic cells in a transwell culture system under laboratory conditions. Monocytes were differentiated into immature dendritic cells (iDCs) in the presence of GM-CSF and IL-4 for 6 days and then differentiated into mature dendritic cells (mDCs) in the presence of TNF-for 2 days. In every stage of differentiation, immature and mature dendritic cells were separately cocultured with UC-MSCs and BM-MSCs. The findings showed that UC-MSCs and BM-MSCs inhibited strongly differentiation and maturation of dendritic cells at higher dilution ratios (1:1). The BM-MSCs and UC-MSCs showed more inhibitory effect on CD1a, CD83, CD86 expression, and dendritic cell endocytic activity, respectively. On the other hand, these cells severely up-regulated CD14 marker expression. We concluded that UC-MSCs and BM-MSCs could inhibit differentiation, maturation and endocytosis in monocyte-derived DCs through the secreted factors and free of any cellcell contacts under laboratory conditions. As DCs are believed to be the main antigen presenting cells for naive T cells in triggering immune responses, it would be logical that their inhibitory effect on differentiation, maturation and function can decrease or modulate immune and inflammatory responses. Copyright © Spring 2013, Iran J Allergy Asthma Immunol. All rights reserved
Research on the bio-distribution of interferon gamma-containing pharmacocytes
Viral hepatitis B and C- is a widespread infectious disease of the liver and is a potential
threat to human life. Treatment of HCV and HBV requires prolonged (parenteral or oral) administration
of antiviral and immune-stimulating agents, which often have serious side effects that lead to abrupt
termination of the therapy and the development of viral resistance. Targeted delivery of drugs directly
to the affected organ is one of the most promising areas that seek to improve the outcome of treatment
of patients with chronic diseases. Among the various drug delivery systems, erythrocytic pharmacocytes
are of special interest. They are a shade of red blood cells, that could be loaded with antiviral drugs and
drugs that boost the immune system. Owing to the fact that erythrocytes are destroyed by mononuclear
phagocytes in the liver, it is assumable that the EP serve as a promising and direct means of delivering
antiviral drugs and immune-modulators into the liver parenchyma to treat viral hepatitis
The Non-BPS Black Hole Attractor Equation
We study the attractor mechanism for extremal non-BPS black holes with an
infinite throat near horizon geometry, developing, as we do so, a physical
argument as to why such a mechanism does not exist in non-extremal cases. We
present a detailed derivation of the non-supersymmetric attractor equation.
This equation defines the stabilization of moduli near the black hole horizon:
the fixed moduli take values specified by electric and magnetic charges
corresponding to the fluxes in a Calabi Yau compactification of string theory.
They also define the so-called double-extremal solutions. In some examples,
studied previously by Tripathy and Trivedi, we solve the equation and show that
the moduli are fixed at values which may also be derived from the critical
points of the black hole potential.Comment: 32 Pages, 2 Figures, LaTeX; v2: typos corrected, references adde
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