83 research outputs found
The Globular Cluster System of M60 (NGC 4649). I. CFHT MOS Spectroscopy and Database
We present the measurement of radial velocities for globular clusters in M60,
giant elliptical galaxy in the Virgo cluster. Target globular cluster
candidates were selected using the Washington photometry based on the deep
16\arcmin \times 16\arcmin images taken at the KPNO 4m and using the
photometry derived from the HST/WFPC2 archive images. The spectra of the target
objects were obtained using the Multi-Object Spectrograph (MOS) at the
Canada-France-Hawaii Telescope (CFHT). We have measured the radial velocity for
111 objects in the field of M60: 93 globular clusters (72 blue globular
clusters with and 21 red globular clusters with
), 11 foreground stars, 6 small galaxies, and the nucleus of
M60. The measured velocities of the 93 globular clusters range from
km s to km s, with a mean value of
km s, which is in good agreement with the velocity of the nucleus of M60
( km s). Combining our results with data in the
literature, we present a master catalog of radial velocities for 121 globular
clusters in M60. The velocity dispersion of the globular clusters in the master
catalog is found to be km s for the entire sample,
km s for 83 blue globular clusters, and
km s for 38 red globular clusters.Comment: 29 pages, 8 figures. To appear in Ap
The Globular Cluster System of M60 (NGC 4649). II. Kinematics of the Globular Cluster System
We present a kinematic analysis of the globular cluster (GC) system in the
giant elliptical galaxy (gE) M60 in the Virgo cluster. Using the photometric
and spectroscopic database of 121 GCs (83 blue GCs and 38 red GCs), we have
investigated the kinematics of the GC system. We have found that the M60 GC
system shows a significant overall rotation. The rotation amplitude of the blue
GCs is slightly smaller than or similar to that of the red GCs, and their
angles of rotation axes are similar. The velocity dispersions about the mean
velocity and about the best fit rotation curve for the red GCs are marginally
larger than those for the blue GCs. Comparison of observed stellar and GC
velocity dispersion profiles with those calculated from the stellar mass
profile shows that the mass-to-light ratio should be increased as the
galactocentric distance increases, indicating the existence of an extended dark
matter halo. The entire sample of GCs in M60 is found to have a tangentially
biased velocity ellipsoid unlike the GC systems in other gEs. Two subsamples
appear to have different velocity ellipsoids. The blue GC system has a modest
tangentially biased velocity ellipsoid, while the red GC system has a modest
radially biased or an isotropic velocity ellipsoid. From the comparison of the
kinematic properties of the M60 GC system to those of other gEs (M87, M49, NGC
1399, NGC 5128, and NGC 4636), it is found that the velocity dispersion of the
blue GC system is similar to or larger than that of the red GC system except
for M60, and the rotation of the GC system is not negligible. The entire sample
of each GC system shows an isotropic velocity ellipsoid except for M60, while
the subsamples show diverse velocity ellipsoids. We discuss the implication of
these results for the formation models of the GC system in gEs.Comment: 48 pages, 16 figures. To appear in Ap
Shuttle-effect-free sodiumâsulfur batteries derived from a TrĂśger's base polymer of intrinsic microporosity
Room-temperature sodium-sulfur (RT Na-S) batteries have recently gained attention as next-generation energy storage devices owing to their low cost, the abundance of sodium, and the high theoretical capacity of sulfur. However, the notorious shuttle effect, caused by the dissolution of intermediate polysulfides during cycling, limits the long-term performance of Na-S batteries. In this study, intrinsically microporous Tro center dot ger's base based polymer (PIM-EA-TB)-based carbon-sulfur composites are prepared for shuttle-effect-free RT Na-S batteries by utilizing the combination of physical confinement and covalent bonding in a single material. The composites demonstrate excellent electrochemical performance, including a negligible capacity fading over 350 cycles and a high coulombic efficiency of approximately greater than 99%.
L-Type Ca2+ Channel Inhibition Rescues the LPS-Induced Neuroinflammatory Response and Impairments in Spatial Memory and Dendritic Spine Formation
Ca2+ signaling is implicated in the transition between microglial surveillance and activation. Several L-type Ca2+ channel blockers (CCBs) have been shown to ameliorate neuroinflammation by modulating microglial activity. In this study, we examined the effects of the L-type CCB felodipine on LPS-mediated proinflammatory responses. We found that felodipine treatment significantly diminished LPS-evoked proinflammatory cytokine levels in BV2 microglial cells in an L-type Ca2+ channel-dependent manner. In addition, felodipine leads to the inhibition of TLR4/AKT/STAT3 signaling in BV2 microglial cells. We further examined the effects of felodipine on LPS-stimulated neuroinflammation in vivo and found that daily administration (3 or 7 days, i.p.) significantly reduced LPS-mediated gliosis and COX-2 and IL-1?? levels in C57BL/6 (wild-type) mice. Moreover, felodipine administration significantly reduced chronic neuroinflammation-induced spatial memory impairment, dendritic spine number, and microgliosis in C57BL/6 mice. Taken together, our results suggest that the L-type CCB felodipine could be repurposed for the treatment of neuroinflammation/cognitive function-associated diseases
A Comparative Study on the Efficacy of Covered Metal Stent and Plastic Stent in Unresectable Malignant Biliary Obstruction
Background/AimsThe placement of self expandable metal stent (SEMS) is one of the palliative therapeutic options for patients with unresectable malignant biliary obstruction. The aim of this study was to compare the effectiveness of a covered SEMS versus the conventional plastic stent.MethodsWe retrospectively evaluated 44 patients with unresectable malignant biliary obstruction who were treated with a covered SEMS (21 patients) or a plastic stent (10 Fr, 23 patients). We analyzed the technical success rate, functional success rate, early complications, late complications, stent patency and survival rate.ResultsThere was one case in the covered SEMS group that had failed technically, but was corrected successfully using lasso. Functional success rates were 90.5% in the covered SEMS group and 91.3% in the plastic stent group. There was no difference in early complications between the two groups. Median patency of the stent was significantly prolonged in patients who had a covered SEMS (233.6 days) compared with those who had a plastic stent (94.6 days) (p=0.006). During the follow-up period, stent occlusion occurred in 11 patients of the covered SEMS group. Mean survival showed no significant difference between the two groups (covered SEMS group, 236.9 days; plastic stent group, 222.3 days; p=0.182).ConclusionsThe patency of the covered SEMS was longer than that of the plastic stent and the lasso of the covered SEMS was available for repositioning of the stent
Acute respiratory alkalosis occurring after endoscopic third ventriculostomy -A case report-
An endoscopic third ventriculostomy was performed in a 55-year-old man with an obstructive hydrocephalus due to aqueductal stenosis. The vital signs and laboratory studies upon admission were within the normal limits. Anesthesia was maintained with nitrous oxide in oxygen and 6% desflurane. The patient received irrigation with approximately 3,000 ml normal saline during the procedure. Anesthesia and operation were uneventful. However, he developed postoperative hyperventilation in the recovery room, and arterial blood gas analysis revealed acute respiratory alkalosis. We report a rare respiratory alkalosis that occurred after an endoscopic third ventriculostomy
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