3,876 research outputs found
Presence of \u3cem\u3ePorphyromonas gingivalis\u3c/em\u3e in gingival squamous cell carcinoma
Periodontal disease has been recently linked to a variety of systemic conditions such as diabetes, cardiovascular disease, preterm delivery, and oral cancer. The most common bacteria associated with periodontal disease, Porphyromonas gingivalis (P. gingivalis) has not yet been studied in the malignant gingival tissues. The objective of this study was to investigate the presence of P. gingivalis in specimens from squamous cell carcinoma patients. We have performed immunohistochemical staining to investigate the presence of P. gingivalis and Streptococcus gordonii (S. gordonii), a non invasive oral bacteria, in paraffin embedded samples of gingival squamous cell carcinoma (n=10) and normal gingiva (n=5). Staining for P. gingivalis revealed the presence of the bacteria in normal gingival tissues and gingival carcinoma, with higher levels (more than 33%,P\u3c0.05) detected in the carcinoma samples. The staining intensity was also significantly enhanced in the malignant tissue by 2 folds (P\u3c0.023) compared to specimens stained for the non‐invasive S. gordonii. P. gingivalis is abundantly present in malignant oral epithelium suggesting a potential association of the bacteria with gingival squamous cell carcinoma
Phase diagram of a Disordered Boson Hubbard Model in Two Dimensions
We study the zero-temperature phase transition of a two-dimensional
disordered boson Hubbard model. The phase diagram of this model is constructed
in terms of the disorder strength and the chemical potential. Via quantum Monte
Carlo simulations, we find a multicritical line separating the weak-disorder
regime, where a random potential is irrelevant, from the strong-disorder
regime. In the weak-disorder regime, the Mott-insulator-to-superfluid
transition occurs, while, in the strong-disorder regime, the
Bose-glass-to-superfluid transition occurs. On the multicritical line, the
insulator-to-superfluid transition has the dynamical critical exponent and the correlation length critical exponent ,
that are different from the values for the transitions off the line. We suggest
that the proliferation of the particle-hole pairs screens out the weak disorder
effects.Comment: 4 pages, 4 figures, to be published in PR
Nova-Like Cataclysmic Variable TT Ari: QPO Behaviour Coming Back From Positive Superhumps
We study the variability of the nova-like cataclysmic variable TT Ari, on
time-scales of between minutes and months. The observations in the filter R
were obtained at the 40-cm telescope of the Chungbuk National University
(Korea). TT Ari was in the "negative superhump" state after its return from the
"positive superhump" state, which lasted 8 years. The ephemeris for 12 best
pronounced minima is where
numbers in digits are errors in units of the last digit. The phases of minima
may reach 0.2, indicating non-eclipse nature of these minima. The
quasi-periodic oscillations (QPO) are present with a mean "period" of 21.6 min
and mean semi-amplitude of 36 mmag. This value is consistent with the range
15-25 minutes reported for previous "negative superhump" states and does not
support the hypothesis of secular decrease of the QPO period.
Either the period, or the semi-amplitude show significant night-to-night
variations. According to the position at the two-parameter diagrams, the
interval of observations was splitted into 5 parts, showing different
characteristics which are discussed in this paper. The system is an excellent
laboratory to study processes resulting in variations at time-scales from
seconds to decades and needs further monitoring at various states of activity.Comment: 14pages,10figures, accepted in Astronomy and Astrophysic
Characteristic molecular properties of one-electron double quantum rings under magnetic fields
The molecular states of conduction electrons in laterally coupled quantum
rings are investigated theoretically. The states are shown to have a distinct
magnetic field dependence, which gives rise to periodic fluctuations of the
tunnel splitting and ring angular momentum in the vicinity of the ground state
crossings. The origin of these effects can be traced back to the Aharonov-Bohm
oscillations of the energy levels, along with the quantum mechanical tunneling
between the rings. We propose a setup using double quantum rings which shows
that Aharonov-Bohm effects can be observed even if the net magnetic flux
trapped by the carriers is zero.Comment: 16 pages (iopart format), 10 figures, accepted in J.Phys.Cond.Mat
New model for system of mesoscopic Josephson contacts
Quantum fluctuations of the phases of the order parameter in 2D arrays of
mesoscopic Josephson junctions and their effect on the destruction of
superconductivity in the system are investigated by means of a quantum-cosine
model that is free of the incorrect application of the phase operator. The
proposed model employs trigonometric phase operators and makes it possible to
study arrays of small superconducting granules, pores filled with superfluid
helium, or Josephson junctions in which the average number of particles
(effective bosons, He atoms, and so on) is small, and the standard approach
employing the phase operator and the particle number operator as conjugate ones
is inapplicable. There is a large difference in the phase diagrams between
arrays of macroscopic and mesoscopic objects for and ( is
the characteristic interaction energy of the particle per granule and is
the Josephson coupling constant). Reentrant superconductivity phenomena are
discussed.Comment: 4 pages, 3 Postscript figure
OGLE-2015-BLG-0051/KMT-2015-BLG-0048Lb: a Giant Planet Orbiting a Low-mass Bulge Star Discovered by High-cadence Microlensing Surveys
We report the discovery of an extrasolar planet detected from the combined
data of a microlensing event OGLE-2015-BLG-0051/KMT-2015-BLG-0048 acquired by
two microlensing surveys. Despite that the short planetary signal occurred in
the very early Bulge season during which the lensing event could be seen for
just about an hour, the signal was continuously and densely covered. From the
Bayesian analysis using models of the mass function, matter and velocity
distributions combined with the information of the angular Einstein radius, it
is found that the host of the planet is located in the Galactic bulge. The
planet has a mass and it is orbiting a
low-mass M-dwarf host with a projected separation AU.
The discovery of the planet demonstrates the capability of the current
high-cadence microlensing lensing surveys in detecting and characterizing
planets.Comment: 7 pages, 6 figure
General approaches for shear-correcting coordinate transformations in Bragg coherent diffraction imaging: Part 2
X-ray Bragg coherent diffraction imaging has been demonstrated as a powerful three-dimensional (3D) microscopy approach for the investigation of sub-micrometer-scale crystalline particles. It is based on the measurement of a series of coherent diffraction intensity patterns that are numerically inverted to retrieve an image of the spatial distribution of relative phase and amplitude of the Bragg structure factor of the scatterer. This 3D information, which is collected through an angular rotation of the sample, is necessarily obtained in a non-orthogonal frame in Fourier space that must be eventually reconciled. To deal with this, the currently favored approach (detailed in Part I) is to perform the entire inversion in conjugate non-orthogonal real and Fourier space frames, and to transform the 3D sample image into an orthogonal frame as a post-processing step for result analysis. In this article, a direct follow-up of Part I, we demonstrate two different transformation strategies that enable the entire inversion procedure of the measured data set to be performed in an orthogonal frame. The new approaches described here build mathematical and numerical frameworks that apply to the cases of evenly and non-evenly sampled data along the direction of sample rotation (the rocking curve). The value of these methods is that they rely on and incorporate significantly more information about the experimental geometry into the design of the phase retrieval Fourier transformation than the strategy presented in Part I. Two important outcomes are 1) that the resulting sample image is correctly interpreted in a shear-free frame, and 2) physically realistic constraints of BCDI phase retrieval that are difficult to implement with current methods are easily incorporated. Computing scripts are also given to aid readers in the implementation of the proposed formalisms
OGLE-2017-BLG-1522: A giant planet around a brown dwarf located in the Galactic bulge
We report the discovery of a giant planet in the OGLE-2017-BLG-1522
microlensing event. The planetary perturbations were clearly identified by
high-cadence survey experiments despite the relatively short event timescale of
days. The Einstein radius is unusually small, mas, implying that the lens system either has very low mass or
lies much closer to the microlensed source than the Sun, or both. A Bayesian
analysis yields component masses and source-lens
distance , implying that this is a
brown-dwarf/Jupiter system that probably lies in the Galactic bulge, a location
that is also consistent with the relatively low lens-source relative proper
motion . The projected
companion-host separation is , indicating that
the planet is placed beyond the snow line of the host, i.e., . Planet formation scenarios combined with the small
companion-host mass ratio and separation suggest that the
companion could be the first discovery of a giant planet that formed in a
protoplanetary disk around a brown dwarf host.Comment: 20 pages, 6 figure
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