73 research outputs found
Salt, Hot Water, and Silicon Compounds Tracing Massive Twin Disks
We report results of 0.05"-resolution observations toward the O-type
proto-binary system IRAS 16547-4247 with the Atacama Large
Millimeter/submillimeter Array (ALMA). We present dynamical and chemical
structures of the circumbinary disk, circumstellar disks, outflows and jets,
illustrated by multi-wavelength continuum and various molecular lines. In
particular, we detect sodium chloride, silicon compounds, and
vibrationally-excited water lines as probes of the individual protostellar
disks at a scale of 100 au. These are complementary to typical hot-core
molecules tracing the circumbinary structures on a 1000-au scale. The H2O line
tracing inner-disks has an upper-state energy of Eu/k>3000K, indicating a high
temperature of the disks. On the other hand, despite the detected transitions
of NaCl, SiO, and SiS not necessarily having high upper-state energies, they
are enhanced only in the vicinity of the protostars. We interpret that these
molecules are the products of dust destruction, which only happens in the inner
disks. This is the second detection of alkali metal halide in protostellar
systems after the case of the disk of Orion Source I, and also one of few
massive protostellar disks associated with high-energy transition water and
silicon compounds. These new results suggest these "hot-disk" lines may be
common in innermost disks around massive protostars, and have great potential
for future research of massive star formation. We also tentatively find that
the twin disks are counter-rotating, which might give a hint of the origin of
the massive proto-binary system IRAS 16547-4247.Comment: 15 pages, 5 figures, 2 appendix figures. Published in ApJ Letter
Fundamental Parameters of the Milky Way Galaxy Based on VLBI astrometry
We present analyses to determine the fundamental parameters of the Galaxy
based on VLBI astrometry of 52 Galactic maser sources obtained with VERA, VLBA
and EVN. We model the Galaxy's structure with a set of parameters including the
Galaxy center distance R_0, the angular rotation velocity at the LSR Omega_0,
mean peculiar motion of the sources with respect to Galactic rotation (U_src,
V_src, W_src), rotation-curve shape index, and the V component of the Solar
peculiar motions V_sun. Based on a Markov chain Monte Carlo method, we find
that the Galaxy center distance is constrained at a 5% level to be R_0 = 8.05
+/- 0.45 kpc, where the error bar includes both statistical and systematic
errors. We also find that the two components of the source peculiar motion
U_src and W_src are fairly small compared to the Galactic rotation velocity,
being U_src = 1.0 +/- 1.5 km/s and W_src = -1.4 +/- 1.2 km/s. Also, the
rotation curve shape is found to be basically flat between Galacto-centric
radii of 4 and 13 kpc. On the other hand, we find a linear relation between
V_src and V_sun as V_src = V_sun -19 (+/- 2) km/s, suggesting that the value of
V_src is fully dependent on the adopted value of V_sun. Regarding the rotation
speed in the vicinity of the Sun, we also find a strong correlation between
Omega_0 and V_sun. We find that the angular velocity of the Sun, Omega_sun,
which is defined as Omega_sun = Omega_0 + V_sun/R_0, can be well constrained
with the best estimate of Omega_sun = 31.09 +/- 0.78 km/s/kpc. This corresponds
to Theta_0 = 238 +/- 14 km/s if one adopts the above value of R_0 and recent
determination of V_sun ~ 12 km/s.Comment: 14 pages, 6 figures, PASJ in pres
Inhibitory Action of Quercetin on Eosinophil Activation In Vitro
The influence of quercetin on eosinophil functions was examined in vitro and in vivo. The first set of experiments was undertaken to examine whether quercetin could suppress eosinophilia and IgE hyperproduction induced by Mesocestoides corti infection in BALB/c mice. The number of peripheral blood eosinophils and IgE levels were examined 21 days after infection. Oral administration of quercetin for 21 days could not suppress both peripheral blood eosinophilia and IgE hyperproduction, even when 20.0 mg/kg quercetin was used for treatment. The second part of the experiment was designed to examine the influence of quercetin on eosinophil activation induced by SCF stimulation in vitro. Eosinophils were obtained from M. corti-infected mice and stimulated with SCF in the presence of various concentrations of quercetin for 24 h. The addition of quercetin into cell cultures could suppress eosinophil activation induced by SCF stimulation as assessed by measuring the contents of RANTES, MIP-1β, ECP, and MBP in culture supernatants. The minimum concentration of quercetin which caused significant suppression of factor secretion was 5.0 μM. These results may suggest that quercetin will be a good candidate for the supplement on the management of eosinophil-mediated diseases, such as allergic rhinitis and asthma
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