66 research outputs found
Rational design for thermochromic luminescence in amorphous polystyrene films with bis-o-carborane-substituted enhanced conjugated molecule having aggregation-induced luminochromism
We designed the triad molecule, bis-o-carborane-substituted bis(thienylethynyl)benzene, as a filler for realizing thermochromic luminescent behaviors based on conventional polymer films, such as polystyrene. From the optical measurements, it was found that the triad can show solid-state emission and dual-luminescent properties with variable intensity ratios depending on media. From the mechanistic studies including the experiments with the methyl-substituted model compound, it was revealed that dual emission should be originated from the locally excited and twisted intramolecular charge transfer states, and the latter emission band is significantly enhanced in the solid states. We prepared amorphous films containing variable concentrations of the triad with the spin-coating method and investigated optical properties. It was found that intensity ratios were drastically changed by altering the concentration of the triad. By increasing the proportion of the triad, aggregation occurred, and emission color was apparently varied through the changes in intensity ratios of the dual emission property. Based on the aggregation-induced luminochromic property of the triad, thermochromic luminescence was finally realized by heating the amorphous films. The rational design for obtaining thermochromic luminescent amorphous films is illustrated in this paper
Effect of vasopressin V1- and V2-receptor stimulation on blood pressure in DOCA-salt hypertensive rats.
We recently reported that stimulation of the arginine vasopressin (AVP) V1-receptor enhanced the pressor response in spontaneously hypertensive rats (SHR). In the present study, we investigated acute changes in systolic blood pressure (SBP) and heart rate (HR) after intravenous injections of AVP, OPC-21268 (a V1-receptor antagonist), and OPC-31260 (a V2-receptor antagonist), in anesthetized DOCA-salt hypertensive rats (DOCA) and age-matched sham-operated Wistar rats (control) to determine whether the pressor effect is specific to SHR or is present in other hypertensive animal models. SBP increased significantly in DOCA rats 9 min after injection of AVP 5 ng/kg without a concomitant increase in HR. Neither OPC-21268 3mg/kg nor OPC-31260 3mg/kg caused significant changes in SBP or HR. SBP tended to increase when AVP was administered after injection of OPC-31260. HR increased significantly 15 min after the combined treatment with OPC-31260 and AVP in DOCA rats compared with control rats. SBP did not change significantly when AVP was administered after injection of OPC-21268 in DOCA or control rats, but HR decreased significantly from 1 to 4 min after injection of AVP in DOCA rats. Our results suggest that V1-receptor stimulation does not enhance the pressor response in the DOCA rat, which is a model of volume-dependent hypertension, suggesting that the AVP system, especially V1-receptor, is not as important in the development or maintenance of hypertension in DOCA rats as in SHR.</p
Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) VIII. A less biased view of the early co-evolution of black holes and host galaxies
We present ALMA [CII] line and far-infrared (FIR) continuum observations of
three low-luminosity quasars () discovered by our
Subaru Hyper Suprime-Cam (HSC) survey. The [CII] line was detected in all three
targets with luminosities of , about one order
of magnitude smaller than optically luminous ()
quasars. The FIR continuum luminosities range from
(3 limit) to , indicating a wide range
in star formation rates in these galaxies. Most of the HSC quasars studied thus
far show [CII]/FIR luminosity ratios similar to local star-forming galaxies.
Using the [CII]-based dynamical mass () as a surrogate for bulge
stellar mass (), we find that a significant fraction of
low-luminosity quasars are located on or even below the local relation, particularly at the massive end of the galaxy mass
distribution. In contrast, previous studies of optically luminous quasars have
found that black holes are overmassive relative to the local relation. Given
the low luminosities of our targets, we are exploring the nature of the early
co-evolution of supermassive black holes and their hosts in a less biased way.
Almost all of the quasars presented in this work are growing their black hole
mass at much higher pace at than the parallel growth model, in which
supermassive black holes and their hosts grow simultaneously to match the local
relation at all redshifts. As the low-luminosity
quasars appear to realize the local co-evolutionary relation even at , they should have experienced vigorous starbursts prior to the currently
observed quasar phase to catch up with the relation.Comment: 19 pages, 11 figures, 4 tables. Accepted for publication in
Publications of the Astronomical Society of Japan (PASJ
Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) III. Star formation properties of the host galaxies at studied with ALMA
We present our ALMA Cycle 4 measurements of the [CII] emission line and the
underlying far-infrared (FIR) continuum emission from four optically
low-luminosity () quasars at discovered by
the Subaru Hyper Suprime Cam (HSC) survey. The [CII] line and FIR continuum
luminosities lie in the ranges
and , which are at least one
order of magnitude smaller than those of optically-luminous quasars at . We estimate the star formation rates (SFR) of our targets as
. Their line and continuum-emitting
regions are marginally resolved, and found to be comparable in size to those of
optically luminous quasars, indicating that their SFR or likely gas mass
surface densities (key controlling parameter of mass accretion) are accordingly
different. The ratios of the hosts, , are fully consistent with local star-forming
galaxies. Using the [CII] dynamics, we derived their dynamical masses within a
radius of 1.5-2.5 kpc as . By
interpreting these masses as stellar ones, we suggest that these faint quasar
hosts are on or even below the star-forming main sequence at , i.e.,
they appear to be transforming into quiescent galaxies. This is in contrast to
the optically luminous quasars at those redshifts, which show starburst-like
properties. Finally, we find that the ratios of black hole mass to host galaxy
dynamical mass of the most of low-luminosity quasars including the HSC ones are
consistent with the local value. The mass ratios of the HSC quasars can be
reproduced by a semi-analytical model that assumes merger-induced black
hole-host galaxy evolution.Comment: 20 pages, 9 figures, 4 tables. Accepted for publication in PAS
Enhanced pressor response in spontaneously hypertensive rats induced by stimulation of vasopressin-V1 receptors.
To elucidate the effect of the arginine vasopressin (AVP) system in vivo, especially V1 and V2 activity, on blood pressure, we measured the acute changes in blood pressure and heart rate after AVP, OPC-21,268 (a V1 receptor antagonist), and OPC-31,260 (a V2 receptor antagonist) were injected intravenously in anesthetized spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats at the age of 15 weeks. Compared with the control period, single injection of AVP 5 ng/kg significantly increased systolic blood pressure in WKY rats without a concomitant increase in heart rate, but there was no significant increase in blood pressure in SHR. In contrast, single injection of either OPC-21,268 3 mg/kg or OPC-31,260 3 mg/kg did not affect blood pressure or heart rate in either SHR or WKY rats. Injection of AVP after the administration of OPC-31,260 induced a greater increase in blood pressure in SHR than in WKY rats, whereas injection of AVP after the administration of OPC-21,268 did not induce any clear increase in blood pressure in SHR or WKY rats. These results suggest that SHR have enhanced pressor activity mediated by V1 receptors and that this increase may be due to an increase in their number. In conclusion, enhancement of V1 activity may contribute to the development of high blood pressure in SHR.</p
Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). XIV. A Candidate Type-II Quasar at z=6.1292
We present deep Keck/MOSFIRE near-infrared spectroscopy of a strong Lyman
alpha emitting source at z=6.1292, HSC J142331.71-001809.1, which was
discovered by the SHELLQS program from imaging data of the Subaru Hyper
Suprime-Cam (HSC) survey. This source is one of five objects that show
unresolved (10^44 erg s-1) Lyman alpha emission
lines at absolute 1450 angstrom continuum magnitudes of M1450~-22 mag. Its
rest-frame Lyman alpha equivalent width (EW) is 370+/-30 angstrom. In the 2
hour Keck/MOSFIRE spectrum in Y band, the high-ionization CIV 1548,1550 doublet
emission line was clearly detected with FWHM =120+/-20 km s-1 and a total
rest-frame EW of 37-5+6 angstrom. We also report the detection of weak
continuum emission, and the tentative detection of OIII] 1661,1666 in the 4
hour J band spectrum. Judging from the UV magnitude, line widths, luminosities,
and EWs of Lyman alpha and CIV, we suggest that this source is a
reionization-era analog of classical type-II AGNs, although there is a
possibility that it represents a new population of AGN/galaxy composite objects
in the early universe. We compare the properties of J1423-0018 to
intermediate-redshift type-II AGNs and CIV emitters seen in z=6-7 galaxy
samples. Further observations of other metal emission lines in the rest-frame
UV or optical, and X-ray follow-up observations of the z=6-7 narrow-line
quasars are needed for more robust diagnostics and to determine their nature.Comment: 15 pages, 8 figures, accepted for publication in the Astrophysical
Journa
SERENADE II: An ALMA Multi-Band Dust-Continuum Analysis of 28 Galaxies at and the Physical Origin of the Dust Temperature Evolution
We present an analysis of ALMA multi-band dust-continuum observations for 28
spectroscopically-confirmed bright Lyman-break galaxies at . Our sample
consists of 11 galaxies at newly observed in our ALMA program, which
substantially increases the number of galaxies with both rest-frame 88
and 158 continuum observations, allowing us to simultaneously
measure the IR luminosity and dust temperature for a statistical sample of
galaxies for the first time. We derive the relationship between the
UV slope () and infrared excess (IRX) for the
galaxies, and find a shallower IRX- relation compared to the
previous results at --4. Based on the IRX- relation
consistent with our results and the - relation
including fainter galaxies in the literature, we find a limited contribution of
the dust-obscured star formation to the total SFR density, at
. Our measurements of the dust temperature at , on average, supports a gentle increase of
from to --7. Using an analytic model with
parameters consistent with recent {\it{JWST}} results, we discuss that the
observed redshift evolution of the dust temperature can be reproduced by an
increase in the gas depletion timescale and decrease of the metallicity. The variety of observed at
high redshifts can also be naturally explained by scatters around the
star-formation main sequence and average mass-metallicity relation, including
an extremely high dust temperature of observed in a
galaxy at .Comment: Submitted to Ap
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