49 research outputs found
WY-14643, a Potent Peroxisome Proliferator Activator Receptor-α PPAR-α Agonist Ameliorates the Inflammatory Process Associated to Experimental Periodontitis
We have investigated the effects of WY14643, a potent peroxisome proliferator activator receptor-α (PPAR-α) agonist, in a rat model of ligature-induced periodontitis.
Male Sprague-Dawley rats were lightly anaesthetized with pentobarbitone (35 mg/kg). Sterile, 2-0 black braided silk thread was placed around the cervix of the lower left first molar and knotted medially. Animals received WY14643 (1 mg/kg i.p, daily for eight days). Eighths days after placement of the ligature, we evaluated several markers of inflammation such us (1) myeloperoxidase activity, (2) a cytokines and adhesion molecules expression, (3) NF-κB expression, (4) iNOS expression, (5) the nitration of tyrosine residues, (6) activation of the nuclear enzyme poly(ADP-ribose) polymerase, (7) apoptosis, and (8) the degree of gingivomucosal tissues injury. Administration of WY14643 significantly decreased all of the parameters of inflammation as described above. These results demonstrate that WY14643 exerts an anti-inflammatory role during experimental periodontitis and is able to ameliorate the tissue damage
Numerical control matrix rotation for the LINC-NIRVANA Multi-Conjugate Adaptive Optics system
LINC-NIRVANA will realize the interferometric imaging focal station of the
Large Binocular Telescope. A double Layer Oriented multi-conjugate adaptive
optics system assists the two arms of the interferometer, supplying high order
wave-front correction. In order to counterbalance the field rotation,
mechanical derotation for the two ground wave-front sensors, and optical
derotators for the mid-high layers sensors fix the positions of the focal
planes with respect to the pyramids aboard the wave-front sensors. The
derotation introduces pupil images rotation on the wavefront sensors: the
projection of the deformable mirrors on the sensor consequently change. The
proper adjustment of the control matrix will be applied in real-time through
numerical computation of the new matrix. In this paper we investigate the
temporal and computational aspects related to the pupils rotation, explicitly
computing the wave-front errors that may be generated.Comment: 6 pages, 2 figures, presented at SPIE Symposium "Astronomical
Telescopes and Instrumentation'' conference "Adaptive Optics Systems
II'',Sunday 27 June 2010, San Diego, California, US
Magellan Adaptive Optics first-light observations of the exoplanet beta Pic b. II. 3-5 micron direct imaging with MagAO+Clio, and the empirical bolometric luminosity of a self-luminous giant planet
Young giant exoplanets are a unique laboratory for understanding cool,
low-gravity atmospheres. A quintessential example is the massive extrasolar
planet Pic b, which is 9 AU from and embedded in the debris disk of the
young nearby A6V star Pictoris. We observed the system with first light
of the Magellan Adaptive Optics (MagAO) system. In Paper I we presented the
first CCD detection of this planet with MagAO+VisAO. Here we present four
MagAO+Clio images of Pic b at 3.1 m, 3.3 m, , and
, including the first observation in the fundamental CH band. To
remove systematic errors from the spectral energy distribution (SED), we
re-calibrate the literature photometry and combine it with our own data, for a
total of 22 independent measurements at 16 passbands from 0.99--4.8 m.
Atmosphere models demonstrate the planet is cloudy but are degenerate in
effective temperature and radius. The measured SED now covers 80\% of the
planet's energy, so we approach the bolometric luminosity empirically. We
calculate the luminosity by extending the measured SED with a blackbody and
integrating to find log(/) . From our
bolometric luminosity and an age of 233 Myr, hot-start evolutionary tracks
give a mass of 12.70.3 , radius of 1.450.02 , and
of 170823 K (model-dependent errors not included). Our
empirically-determined luminosity is in agreement with values from atmospheric
models (typically dex), but brighter than values from the field-dwarf
bolometric correction (typically dex), illustrating the limitations in
comparing young exoplanets to old brown dwarfs.Comment: Accepted to ApJ. 27 pages, 22 figures, 19 table
On the Morphology and Chemical Composition of the HR 4796A Debris Disk
[abridged] We present resolved images of the HR 4796A debris disk using the
Magellan adaptive optics system paired with Clio-2 and VisAO. We detect the
disk at 0.77 \microns, 0.91 \microns, 0.99 \microns, 2.15 \microns, 3.1
\microns, 3.3 \microns, and 3.8 \microns. We find that the deprojected center
of the ring is offset from the star by 4.761.6 AU and that the deprojected
eccentricity is 0.060.02, in general agreement with previous studies. We
find that the average width of the ring is 14, also comparable to
previous measurements. Such a narrow ring precludes the existence of
shepherding planets more massive than \about 4 \mj, comparable to hot-start
planets we could have detected beyond \about 60 AU in projected separation.
Combining our new scattered light data with archival HST/STIS and HST/NICMOS
data at \about 0.5-2 \microns, along with previously unpublished Spitzer/MIPS
thermal emission data and all other literature thermal data, we set out to
constrain the chemical composition of the dust grains. After testing 19
individual root compositions and more than 8,400 unique mixtures of these
compositions, we find that good fits to the scattered light alone and thermal
emission alone are discrepant, suggesting that caution should be exercised if
fitting to only one or the other. When we fit to both the scattered light and
thermal emission simultaneously, we find mediocre fits (reduced chi-square
\about 2). In general, however, we find that silicates and organics are the
most favored, and that water ice is usually not favored. These results suggest
that the common constituents of both interstellar dust and solar system comets
also may reside around HR 4796A, though improved modeling is necessary to place
better constraints on the exact chemical composition of the dust.Comment: Accepted to ApJ on October 27, 2014. 21 pages, 12 figures, 4 table
Status of MagAO and review of astronomical science with visible light adaptive optics
We review astronomical results in the visible (lambda <1 micron) with
adaptive optics and note the status the MagAO system and the recent upgrade to
visible camera's Simultaneous/Spectra Differential Imager (SDI to SDI+) mode.
Since mid-2013 there has been a rapid increase visible AO with over 50 refereed
science papers published in just 2015-2016 timeframe. The main focus of this
paper is another large (D=6.5m Magellan telescope) AO system (MagAO) which has
been very productive in the visible (particularly at the H-alpha emission
line). MagAO is an advanced Adaptive Secondary Mirror (ASM) AO system at the
Magellan in Chile. This ASM secondary has 585 actuators with <1 msec response
times (0.7 ms typically). MagAO utilizes a 1 kHz pyramid wavefront sensor
(PWFS). The relatively small actuator pitch (~22 cm/subap, 300 modes, upgraded
to 30 pix dia. PWFS) allows moderate Strehls to be obtained in the visible
(0.63-1.05 microns). Long exposures (60s) achieve <30mas resolutions and 30%
Strehls at 0.62 microns (r') with the VisAO camera (0.5-1.0 microns) in 0.5"
seeing with bright R < 9 mag stars (~10% Strehls can be obtained on fainter
R~12 mag guide stars). Differential Spectral Imaging (SDI) at H-alpha has been
very important for accreting exoplanet detection. There is also a 1-5micron
science camera (Clio; Morzinski et al. 2016). These capabilities have led to
over 35 MagAO refereed science publications. Here we review the key steps to
having good performance in the visible and review the exciting new AO visible
science opportunities and science results. The recent rapid increase in the
scientific publications and power of visible AO is due to the maturity of the
next-generation of AO systems and our new ability probe circumstellar regions
with very high (10-30 mas) spatial resolutions that would otherwise require
much larger (>10m) diameter telescopes in the infrared.Comment: 18 pages, Proc. SPIE 10703, Adaptive Optics IV, June 2018 Austin TX.
arXiv admin note: substantial text overlap with arXiv:1407.509
Toward large diffraction limited space telescopes with the Latt lightweight active primary
The design of large segmented mirrors, actively controlled both in shape and in differential piston, is one of the challenges space optics is facing, driven by the needs of the astronomical community
Into the Blue: AO Science with MagAO in the Visible
We review astronomical results in the visible ({\lambda}<1{\mu}m) with
adaptive optics. Other than a brief period in the early 1990s, there has been
little astronomical science done in the visible with AO until recently. The
most productive visible AO system to date is our 6.5m Magellan telescope AO
system (MagAO). MagAO is an advanced Adaptive Secondary system at the Magellan
6.5m in Chile. This secondary has 585 actuators with < 1 msec response times
(0.7 ms typically). We use a pyramid wavefront sensor. The relatively small
actuator pitch (~23 cm/subap) allows moderate Strehls to be obtained in the
visible (0.63-1.05 microns). We use a CCD AO science camera called "VisAO".
On-sky long exposures (60s) achieve <30mas resolutions, 30% Strehls at 0.62
microns (r') with the VisAO camera in 0.5" seeing with bright R < 8 mag stars.
These relatively high visible wavelength Strehls are made possible by our
powerful combination of a next generation ASM and a Pyramid WFS with 378
controlled modes and 1000 Hz loop frequency. We'll review the key steps to
having good performance in the visible and review the exciting new AO visible
science opportunities and refereed publications in both broad-band (r,i,z,Y)
and at Halpha for exoplanets, protoplanetary disks, young stars, and emission
line jets. These examples highlight the power of visible AO to probe
circumstellar regions/spatial resolutions that would otherwise require much
larger diameter telescopes with classical infrared AO cameras.Comment: 14 pages, 8 figures, to appear in Proc. SPIE 914