742 research outputs found
Low-Resolution Spectrum of the Diffuse Galactic Light and 3.3 um PAH emission with AKARI InfraRed Camera
We first obtained the spectrum of the diffuse Galactic light (DGL) at general
interstellar space in 1.8-5.3 um wavelength region with the low-resolution
prism spectroscopy mode of the AKARI Infra-Red Camera (IRC) NIR channel. The
3.3 um PAH band is detected in the DGL spectrum at Galactic latitude |b| < 15
deg, and its correlations with the Galactic dust and gas are confirmed. The
correlation between the 3.3 um PAH band and the thermal emission from the
Galactic dust is expressed not by a simple linear correlation but by a relation
with extinction. Using this correlation, the spectral shape of DGL at optically
thin region (5 deg < |b| < 15 deg) was derived as a template spectrum. Assuming
that the spectral shape of this template spectrum is uniform at any position,
DGL spectrum can be estimated by scaling this template spectrum using the
correlation between the 3.3 um PAH band and the thermal emission from the
Galactic dust.Comment: 7 pages, 5 figures, accepted by Publications of the Astronomical
Society of Japan (PASJ
Radiographic bone level and soft tissue dimensional changes following explantation of implants affected by peri-implantitis: A retrospective exploratory evaluation.
BACKGROUND
While the dimensional alteration of alveolar bone following tooth extraction have been extensively descripted in the literature, no information is available regarding potential hard and soft tissues changes following implant explantation.
AIM
To evaluate the radiographic bone healing and the horizontal and vertical soft tissue dimensional alterations at implant extraction alveoli, 6 months following implant explantation.
MATERIAL AND METHODS
Data from 31 patients scheduled for extraction of one implant with persisting peri-implantitis despite treatment were analysed. Bone crest level changes and the extent of bone healing at the apical aspect of the implant socket were assessed on the radiographs prior and 6 months following explantation. Regression analyses assessed the impact of various predictors (e.g., bone crest level, presence/absence of buccal bone) on bone level changes. Fisher's exact probability test was applied to assess the difference in probability to have mucosa recession of ≥2 mm in the presence or absence of alveolar buccal bone.
RESULTS
A vertical bone loss of 0.8 mm (standard deviation [SD] = 1.3) of the peri-implant bone crest and a gain of 0.8 mm (SD = 1.1) from the bottom of the peri-implant defect were recorded. Complete healing was noted in the intact implant extraction socket (i.e., the part of the implant not affected by peri-implantitis). A reduction of 0.4 mm (SD = 0.7) of the alveolar mucosa height was recorded in concomitant with a decrease of 0.7 mm (SD = 0.8) of the mucosa width. These alterations were more pronounced in the absence of the alveolar buccal bone.
CONCLUSION
The results of the present explorative study indicated a decrease in the height and width of the alveolar soft and hard tissues following explantation of peri-implantitis affected implants, and these changes were more pronounced in the absence of the buccal bone wall. Nevertheless, the apical portion of the implant alveolus (the intact implant socket) tend to heal with no further bone loss
Instabilities and turbulence-like dynamics in an oppositely driven binary particle mixture
Using extensive particle-based simulations, we investigate out-of-equilibrium
pattern dynamics in an oppositely driven binary particle system in two
dimensions. A surprisingly rich dynamical behavior including lane formation,
jamming, oscillation and turbulence-like dynamics is found. The ratio of two
friction coefficients is a key parameter governing the stability of lane
formation. When the friction coefficient transverse to the external force
direction is sufficiently small compared to the longitudinal one, the lane
structure becomes unstable to shear-induced disturbances, and the system
eventually exhibits a dynamical transition into a novel turbulence-like phase
characterized by random convective flows. We numerically construct an
out-of-equilibrium phase diagram. Statistical analysis of complex
spatio-temporal dynamics of the fully nonlinear turbulence-like phase suggests
its apparent reminiscence to the swarming dynamics in certain active matter
systems.Comment: 6 pages, 6 figures, accepted for publication in EP
Hydrogen Permeability of Palladium Membrane for Steam-Reforming of Bio-Ethanol
A Palladium membrane was prepared by electro-less plating method on porous stainless steel. The catalytic hydrogen production by steam-reforming of biomass-derived ethanol (bio-ethanol) using a Pd membrane was analyzed by comparing it with those for the reaction using reagent ethanol (the reference sample). And the hydrogen permeability of the palladium membrane was investigated using the same palladium membrane (H2/He selectivity = 249, at ΔP = 0.10 MPa, 873 K). As a result, for bio-ethanol, deposited carbon had a negative influence on the hydrogen-permeability of the palladium membrane and hydrogen purity. The sulfur content in the bio-ethanol may have promoted carbon deposition. By using a palladium membrane, it was confirmed that H2 yield (%) was increased. It can be attributed that methane was converted from ethanol and produced more hydrogen by steam reforming, due to the in situ removal of hydrogen from the reaction location
Spectral Modeling of the Supersoft X-ray Source CAL87 based on Radiative Transfer Codes
Super Soft X-ray Sources (SSS) are white dwarf (WD) binaries that radiate
almost entirely below 1~keV. Their X-ray spectra are often complex when
viewed with the X-ray grating spectrometers, where numerous emission and
absorption features are intermingled and hard to separate. The absorption
features are mostly from the WD atmosphere, for which radiative transfer models
have been constructed. The emission features are from the corona surrounding
the WD atmosphere, in which incident emission from the WD surface is
reprocessed. Modeling the corona requires different solvers and assumptions for
the radiative transfer, which is yet to be achieved. We chose CAL87, a SSS in
the Large Magellanic Cloud, which exhibits emission-dominated spectra from the
corona as the WD atmosphere emission is assumed to be completely blocked by the
accretion disk. We constructed a radiative transfer model for the corona using
the two radiative transfer codes; xstar for a one-dimensional two-stream solver
and MONACO for a three-dimensional Monte Carlo solver. We identified their
differences and limitations in comparison to the spectra taken with the
Reflection Grating Spectrometer onboard the XMM-Newton satellite. We finally
obtained a sufficiently good spectral model of CAL87 based on the radiative
transfer of the corona plus an additional collisionally ionized plasma. In the
coming X-ray microcalorimeter era, it will be required to interpret spectra
based on radiative transfer in a wider range of sources than what is presented
here.Comment: 15 pages, 15 figures, ApJ in pres
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