511 research outputs found
The stellar population and complex structure of the bright-rimmed cloud IC 1396N
Context. IC 1396N is a bright-rimmed cloud associated with an
intermediate-mass star-forming region, where a number of Herbig-Haro objects,
H2 jet-like features, CO molecular outflows, and millimeter compact sources
have been observed. Aims. To study in detail the complex structure of the IC
1396N core and the molecular outflows detected in the region and to reveal the
presence of additional YSOs inside this globule. Methods. We carried out a deep
survey of the IC 1396N region in the J, H, K' broadband filters and deep
high-angular resolution observations in the H2 narrowband filter with NICS at
the TNG telescope. The completeness limits in the 2MASS standard are Ks~17.5,
H~18.5 and J~19.5. Results. A total of 736 sources have been detected in all
three bands within the area where the JHK' images overlap. There are 128
sources detected only in HK', 67 detected only in K', and 79 detected only in
H. We found only few objects exhibiting a Near-Infrared excess and no clear
signs of clustering of sources towards the southern rim. In case of triggered
star formation in the southern rim of the globule, this could be very recent,
because it is not evidenced through Near-Infrared imaging alone. The H2
emission is complex and knotty and shows a large number of molecular hydrogen
features spread over the region, testifying a recent star-formation activity
throughout the whole globule. This emission is resolved into several chains or
groups of knots that sometimes show a jet-like morphology. The shocked cloudlet
model scenario previously proposed to explain the V-shaped morphology of the CO
molecular outflow powered by the intermediate-mass YSO BIMA 2 seems to be
confirmed by the presence of H2 emission at the position of the deflecting
western clump. New possible flows have been discovered in the globule,Comment: Comments: 19 pages, 5 tables, 7 figures. Accepted for publication in
A&
V1647 Orionis (IRAS 05436-0007) : A New Look at McNeil's Nebula
We present a study of the newly discovered McNeil's nebula in Orion using the
JHKs-band simultaneous observations with the near-infrared (NIR) camera SIRIUS
on the IRSF 1.4m telescope. The cometary infrared nebula is clearly seen
extending toward north and south from the NIR source (V1647 Orionis) that
illuminates McNeil's nebula. The compact nebula has an apparent diameter of
about 70 arcsec. The nebula is blue (bright in J) and has a cavity structure
with two rims extending toward north-east and north-west. The north-east rim is
brighter and sharp, while the north-west rim is diffuse. The north-east rim can
be traced out to ~ 40 arcsec from the location of the NIR source. In contrast,
no cavity structure is seen toward the south, although diffuse nebula is
extended out to ~ 20 arcsec. New NIR photometric data show a significant
variation in the magnitudes (> 0.15 mag) of the source of McNeil's nebula
within a period of one week, that is possibly under the phase of eruptive
variables like FUors or EXors.Comment: 13 pages, 5 figures in JPEG format. Accepted for the publication in
PASJ Letter
Who Is Eating the Outflow?: High-Angular Resolution Study of an Intermediate-Mass Protostar in L1206
Up to now only a few intermediate-mass molecular outflows have been studied
with enough high-angular resolution. The aim of this work is to study in detail
the intermediate-mass YSO IRAS 22272+6358A, which is embedded in L1206, and its
molecular outflow, in order to investigate the interaction of the outflow with
the dense protostellar material, and to compare their properties with those of
lower mas counterparts. We carried out OVRO observations of the 2.7 mm
continuum emission, CO(1-0), C18O(1-0), and HC3N(12-11) in order to map with
high-angular resolution the core of L1206, and to derive the properties of the
dust emission, the molecular outflow and the dense protostellar envelope. The
2.7 mm continuum emission has been resolved into four sources, labeled OVRO~1,
2, 3, and 4. The intermediate-mass Class~0/I object OVRO 2, with a mass traced
by the dust emission of 14.2 Msun, is the source associated with IRAS
22272+6358A. The CO(1-0) observations have revealed a very collimated outflow
driven by OVRO 2, at a PA ~140 degr, that has a very weak southeastern red lobe
and a much stronger northwestern blue lobe. Photodissociation toward the red
lobe produced by the ionization front coming from the bright-rimmed diffuse HII
region could be responsible of the morphology of the outflow. The spatial
correlation between the outflow and the elongated dense protostellar material
traced by HC3N(12-11) suggests an interaction between the molecular outflow and
the protostellar envelope. Shocks produced by the molecular outflow, and
possibly by the shock front preceding the ionization front could account for
the southern enhancement of HC3N. The properties of the intermediate-mass
protostar OVRO 2 and the molecular outflow are consistent with those of lower
mass counterparts.Comment: 14 pages, 12 figures, 5 tables. Accepted for publication by A&
Anisotropic magnetic properties of CeAgGe single crystal
In order to investigate the anisotropic magnetic properties of
CeAgGe, we have successfully grown the single crystals, for the first
time, by high temperature solution growth (flux) method. We have performed a
detailed study of the grown single crystals by measuring their electrical
resistivity, magnetic susceptibility, magnetization, specific heat and
magnetoresistance. A clear anisotropy and an antiferromagnetic transition at
= 4.6 K have been observed in the magnetic properties. The magnetic
entropy reaches ln 4 at 20 K indicating that the ground state and the first
excited state are very closely spaced (a quasi-quartet state). From the
specific heat measurements and crystalline electric field (CEF) analysis of the
magnetic susceptibility, we have found the level splitting energies as 5 K and
130 K. The magnetization measurements reveal that the a-axis is the easy axis
of magnetization and the saturation moment is = 1.6 /Ce, corroborating the previous neutron diffraction measurements on a
polycrystalline sample.Comment: Submitted to Phys. Rev.
Reciprocal Changes in Factor XIII and Retinal Transglutaminase Expressions in the Fish Retina During Optic Nerve Regeneration
[email protected] mammals, fish retinal ganglion cells have the capacity to repair their axons even after optic nerve transection. In the process of fish optic nerve regeneration, a large number of genes have been described as regeneration-associated molecules. Using molecular cloning techniques, we identified two types of cDNA clones belonging to the transglutaminase (TG) family which were upregulation genes; one is cellular factor XIII (cFXIII) and the other is a tissue type TG named retinal transglutaminase (TGR). cFXIII mRNA started to increase in the retinal ganglion cells at 1-2 days, peaked at 5-7 days, and returned to the control level by 20 days post optic nerve injury. In contrast, TGR mRNA started to increase at day 5-10, peaked at day 20, and then gradually decreased by day 40 after nerve injury. To elucidate the molecular involvement of these TGs in optic nerve regeneration, we studied the effects of recombinant TGR protein or overexpression of cFXIII using a retinal explant culture system. cFXIII effectively induced neurite outgrowth only from naïve (intact) retinas. In contrast, the TGR protein significantly enhanced neurite outgrowth only from primed retinas, in which the optic nerve had been crushed 5-7 days previously. These reciprocal expressions of cFXIII and TGR suggest that these two types of TGs are important for the neurite sprouting and axonal elongation processes, respectively, during optic nerve regeneration processes
The effect of small bowel transplantation on the morphology and physiology of intestinal muscle: A comparison of autografts versus allografts in dogs
The effects of acute (AR) and chronic rejection (CR) on intestinal smooth muscle that are responsible for the dysmotility following small bowel transplantation (SBTX) are incompletely understood. Jejunal and ileal specimens from normal control dogs (n=7), and autotransplanted dogs were examined at 7 days (n=6) and 1 (n=7), 3 (n=6), 6 (n=6), and 12 months (n=6). Allotransplanted dogs that developed AR (n=8) and CR (n=5) were examined for gross and microscopic morphology (muscle thickness, the number and size of myocytes, and inflammatory infiltrate), and for contractile and intracellular electrical function in vitro. Auto-SBTX did not alter morphology at any period, but contractile function was impaired at 7 days (73.6%) compared with normal intestine. Acute rejection did not influence myocyte number or size, but was associated with a prominent infiltrate of neutrophils and lymphocytes, and severely impaired contractile function (20.6%) compared with auto-SBTX controls. Acute rejection also significantly inhibited the amplitude of slow waves and of inhibitory junction potentials. Chronic rejection caused thickening of muscularis propria by both hyperplasia (175.5%) and hypertrophy (202.6%) accompanied by moderate inflammatory cell infiltrate compared with auto-SBTX controls. We conclude that the marked inflammatory infiltrate into the muscularis propria indicates that the graft muscle is injured by both acute and chronic rejection; impaired function of intestinal smooth muscle following SBTX results from both rejection and the injury associated with transplantation, and chronic rejection following SBTX is associated with both hyperplasia and hypertrophy of the muscularis propria
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