61 research outputs found
Floating Black Hole in the Karch-Randall Model and its Holographic Dual
To investigate the holography in the Karch-Randall (KR) braneworld model, we
construct time-symmetric initial data of black holes floating in the bulk, and
compare it with its holographic dual, which is described by four-dimensional
self-gravitating quantum field theory in asymptotically AdS_4 spacetime. We
also give a definition and an explicit formula of mass in the KR model
extending the definition by Abbott and Deser for asymptotically AdS spacetime.
We obtain supporting evidence for the holography in the KR model such as good
agreements of phase structures and characteristic values between the two
theories, and find clues that the Hawking-Page transition of the
four-dimensional quantum theory in a microcanonical ensemble is holographically
dual to a transition in the bulk black hole configuration.Comment: 24 pages, 11 figure
3D Numerical Simulation of Epidermal Skin Turnover Process Using a Particle Model
Skin is the largest organ of the human body. In recent years, concern regarding the cosmetics area has increased, and research studies on anti-aging therapy or cosmetics have been rapidly conducted. Skin cells are not only changing its shape but also its physical properties during the epidermal skin turnover process. Computational simulation can be useful in further understanding the mechanisms of skin formation. We propose a particle model that can handle complex biological phenomena, including cell interactions and is a suitable method for simulating skin formation. The particle model was applied to simulate three-dimensional skin formation accompanied by proliferation and cornification of skin cells. The simulation results represented and reproduced the epidermal skin turnover phenomenon
3D Numerical Simulation of Epidermal Skin Turnover Process Using a Particle Model
Skin is the largest organ of the human body. In recent years, concern regarding the cosmetics area has increased, and research studies on anti-aging therapy or cosmetics have been rapidly conducted. Skin cells are not only changing its shape but also its physical properties during the epidermal skin turnover process. Computational simulation can be useful in further understanding the mechanisms of skin formation. We propose a particle model that can handle complex biological phenomena, including cell interactions and is a suitable method for simulating skin formation. The particle model was applied to simulate three-dimensional skin formation accompanied by proliferation and cornification of skin cells. The simulation results represented and reproduced the epidermal skin turnover phenomenon
Probing the size of extra dimension with gravitational wave astronomy
In Randall-Sundrum II (RS-II) braneworld model, it has been conjectured
according to the AdS/CFT correspondence that brane-localized black hole (BH)
larger than the bulk AdS curvature scale cannot be static, and it is
dual to a four dimensional BH emitting the Hawking radiation through some
quantum fields. In this scenario, the number of the quantum field species is so
large that this radiation changes the orbital evolution of a BH binary. We
derived the correction to the gravitational waveform phase due to this effect
and estimated the upper bounds on by performing Fisher analyses. We
found that DECIGO/BBO can put a stronger constraint than the current table-top
result by detecting gravitational waves from small mass BH/BH and BH/neutron
star (NS) binaries. Furthermore, DECIGO/BBO is expected to detect 10 BH/NS
binaries per year. Taking this advantage, we found that DECIGO/BBO can actually
measure down to m for 5 year observation if we know that
binaries are circular a priori. This is about 40 times smaller than the upper
bound obtained from the table-top experiment. On the other hand, when we take
eccentricities into binary parameters, the detection limit weakens to m due to strong degeneracies between and eccentricities. We also
derived the upper bound on from the expected detection number of extreme
mass ratio inspirals (EMRIs) with LISA and BH/NS binaries with DECIGO/BBO,
extending the discussion made recently by McWilliams. We found that these less
robust constraints are weaker than the ones from phase differences.Comment: 19 pages, 10 figures. Published in PRD, typos corrected, references
and footnotes adde
Co-appearance of superconductivity and ferromagnetism in a CaRuO nanofilm crystal
By tuning the physical and chemical pressures of layered perovskite materials
we can realize the quantum states of both superconductors and insulators. By
reducing the thickness of a layered crystal to a nanometer level, a nanofilm
crystal can provide novel quantum states that have not previously been found in
bulk crystals. Here we report the realization of high-temperature
superconductivity in CaRuO nanofilm single crystals. CaRuO thin
film with the highest transition temperature (midpoint) of 64~K exhibits
zero resistance in electric transport measurements. The superconducting
critical current exhibited a logarithmic dependence on temperature and was
enhanced by an external magnetic field. Magnetic measurements revealed a
ferromagnetic transition at 180~K and diamagnetic magnetization due to
superconductivity. Our results suggest the co-appearance of superconductivity
and ferromagnetism in CaRuO nanofilm crystals. We also found that the
induced bias current and the tuned film thickness caused a
superconductor-insulator transition. The fabrication of micro-nanocrystals made
of layered material enables us to discuss rich superconducting phenomena in
ruthenates
Time-symmetric initial data of large brane-localized black hole in RS-II model
In the aim of shedding a new light on the classical black hole evaporation
conjecture stating that a static brane-localized black hole (BH) larger than
the bulk curvature scale does not exist in Randall-Sundrum II (RS-II) model, we
investigate time-symmetric initial data with a brane-localized apparent horizon
(AH) and analyzed its properties. We find that a three-parameter family of such
initial data can be constructed by simply placing a brane on a constant time
surface of Schwarzschild anti-de Sitter space. By this method, we unambiguously
confirm that initial data with an arbitrarily large AH area do exist. We
compare the ADM mass and the horizon area of our initial data with that of the
black string (BS) solution, and find that any initial data constructed by this
method do not have a smaller mass than the BS solution when the horizon area is
larger than the size determined by the bulk curvature scale. We further
investigate what kind of configuration realizes the minimum mass for the same
AH area. The configuration that realizes the smallest mass turns out to be the
one close to the BS truncated by a cap. We also demonstrate that the same
method applies to construct initial data in (3+1)-dimensional RS-II brane
world. In this case an exact solution of a brane-localized BH exists but BS
solution does not. Nevertheless, the behavior of the initial data is quite
similar in both cases. We find that the known exact solution always has a
smaller mass than our initial data with the same horizon area. This result
enforces the standard belief that the exact BH solution is the most stable
black object in the four-dimensional RS-II model. These results are all
consistent with the classical BH evaporation conjecture, but unfortunately it
turns out that they do not provide a strong support of it.Comment: 14 pages, 9 figures. Typo correcte
肝細胞癌においてmiR125b-5pはAtaxin1による上皮間葉転換を介してソラフェニブ耐性を示す
The mechanism of resistance to sorafenib in hepatocellular carcinoma (HCC) remains unclear. We analyzed miRNA expression profiles in sorafenib-resistant HCC cell lines (PLC/PRF5-R1/R2) and parental cell lines (PLC/PRF5) to identify the miRNAs responsible for resistance. Drug sensitivity, migration/invasion capabilities, and epithelial-mesenchymal transition (EMT) properties were analyzed by biochemical methods. The clinical relevance of the target genes to survival in HCC patients were assessed using a public database. Four miRNAs were significantly upregulated in PLC/PRF5-R1/-R2 compared with PLC/PRF5. Among them, miR-125b-5p mimic-transfected PLC/PRF5 cells (PLC/PRF5-miR125b) and showed a significantly higher IC50 for sorafenib compared with controls, while the other miRNA mimics did not. PLC/PRF5-miR125b showed lower E-cadherin and higher Snail and vimentin expression—findings similar to those for PLC/PRF5-R2—which suggests the induction of EMT in those cells. PLC/PRF5-miR125b exhibited significantly higher migration and invasion capabilities and induced sorafenib resistance in an in vivo mouse model. Bioinformatic analysis revealed ataxin-1 as a target gene of miR-125b-5p. PLC/PRF5 cells transfected with ataxin-1 siRNA showed a significantly higher IC50, higher migration/invasion capability, higher cancer stem cell population, and an EMT phenotype. Median overall survival in the low-ataxin-1 patient group was significantly shorter than in the high-ataxin-1 group. In conclusion, miR-125b-5p suppressed ataxin-1 and consequently induced Snail-mediated EMT and stemness, leading to a poor prognosis in HCC patients.The mechanism of resistance to multikinase inhibitors in hepatocellular carcinoma (HCC) remains unclear. We analyzed miRNA expression profiles in sorafenib-resistant HCC cell lines (PLC/PRF5-R1/R2) and parental cell lines (PLC/PRF5) to identify the responsible miRNAs and target genes involved in the mechanism of resistance. Four miRNAs were significantly upregulated. Among them, we found that miR-125-5p induced sorafenib resistance in HCC cells and in a mouse model. We also revealed that miR-125-5p suppressed ataxin-1 as a target gene and consequently induced Snail-mediated epithelial-mesenchymal transition (EMT) and cancer stemness. Moreover, we demonstrated that ataxin-1 expression has an impact on the prognosis of patients with HCCs. In the future, by comparing the expression status of miR-125b-5p/ataxin-1 and the effect of sorafenib in the clinical setting, it is expected that miR-125b-5p will be established as an effective drug selection marker for treatment selection in patients with HCC
Quantum Back Reaction to asymptotically AdS Black Holes
We analyze the effects of the back reaction due to a conformal field theory
(CFT) on a black hole spacetime with negative cosmological constant. We study
the geometry numerically obtained by taking into account the energy momentum
tensor of CFT approximated by a radiation fluid. We find a sequence of
configurations without a horizon in thermal equilibrium (CFT stars), followed
by a sequence of configurations with a horizon. We discuss the thermodynamic
properties of the system and how back reaction effects alter the space-time
structure. We also provide an interpretation of the above sequence of solutions
in terms of the AdS/CFT correspondence. The dual five-dimensional description
is given by the Karch-Randall model, in which a sequence of five-dimensional
floating black holes followed by a sequence of brane localized black holes
correspond to the above solutions.Comment: 13 pages, 10 figure
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