153 research outputs found
Inward Motions of the Compact SiO Masers Around VX Sagittarii
We report Very Long Baseline Array (VLBA) observations of 43 GHz v=1, J=1-0
SiO masers in the circumstellar envelope of the M-type semi-regular variable
star VX Sgr at 3 epochs during 1999 April-May. These high-resolution VLBA
images reveal a persistent ringlike distribution of SiO masers with a projected
radius of ~3 stellar radii. The typical angular size of 0.5 mas for individual
maser feature was estimated from two-point correlation function analysis for
maser spots. We found that the apparent size scale of maser features was
distinctly smaller than that observed in the previous observations by comparing
their fractions of total power imaged. This change in the size scale of maser
emission may be related to stellar activity that caused a large SiO flare
during our observations. Our observations confirmed the asymmetric distribution
of maser emission, but the overall morphology has changed significantly with
the majority of masers clustering to the north-east of the star compared to
that lying to the south-west direction in 1992. By identifying 42 matched maser
features appearing in all the three epochs, we determined the contraction of an
SiO maser shell toward VX Sgr at a proper motion of -0.507 mas/yr,
corresponding to a velocity of about 4 km/s at a distance of 1.7 kpc to VX Sgr.
Such a velocity is on the order of the sound speed, and can be easily explained
by the gravitational infall of material from the circumstellar dust shell.Comment: 26 pages, 5 figures, 4 tables, accepted for publication in Ap
Complete removal of heart-compressing large mediastinal lipoma : a case report
An 83-year-old man presented with worsening of respiratory discomfort and underwent close examination, which revealed a large mediastinal lipoma measuring 15 × 10 cm. The patient showed heart failure symptoms due to heart compression by tumor. The tumor was completely removed safely and reliably by cutting the ascending aorta, main pulmonary artery and superior vena cava. Although preoperative examination could not determine whether the tumor was lipoma or liposarcoma, we selected an invasive surgical therapy because neither radiation therapy nor chemotherapy was considered effective for either type of tumor. We report here a very rare case of heart-compressing mediastinal tumor
Correlation between Infrared Colors and Intensity Ratios of SiO Maser Lines
We present the results of SiO millimeter-line observations of a sample of
known SiO maser sources covering a wide dust-temperature range. A cold part of
the sample was selected from the SiO maser sources found in our recent SiO
maser survey of cold dusty objects. The aim of the present research is to
investigate the causes of the correlation between infrared colors and SiO maser
intensity ratios among different transition lines. In particular, the
correlation between infrared colors and SiO maser intensity ratio among the
J=1-0 v=1, 2, and 3 lines are mainly concerned in this paper. We observed in
total 75 SiO maser sources with the Nobeyama 45m telescope quasi-simultaneously
in the SiO J=1-0 v=0, 1, 2, 3, 4 and J=2-1 v=1, 2 lines. We also observed the
sample in the 29SiO J=1-0 v=0 and J=2-1 v=0, and 30SiO J=1-0 v=0 lines, and the
H2O 6(1,6)-5(2,3) line. As reported in previous papers, we confirmed that the
intensity ratios of the SiO J=1-0 v=2 to v=1 lines clearly correlate with
infrared colors. In addition, we found possible correlation between infrared
colors and the intensity ratios of the SiO J=1-0 v=3 to v=1&2 lines. Two
overlap lines of H2O (i.e., 11(6,6) nu_2=1 -> 12(7,5) nu_2=0 and 5(0,5) nu_2=2
-> 6(3,4) nu_2=1) might explain these correlation if these overlap lines become
stronger with increase of infrared colors, although the phenomena also might be
explained by more fundamental ways if we take into account the variation of
opacity from object to object.Comment: 49 pages, 7 figures, 3 tables, accepted for publication in ApJ. Full
resolution version available at
http://www.asiaa.sinica.edu.tw/~junichi/paper
Expression of eicosanoid receptors subtypes and eosinophilic inflammation: implication on chronic rhinosinusitis
BACKGROUND: Eicosanoid receptors are G-protein-coupled receptors playing an important immunomodulatory role in airway diseases. However, there is little information on the expression of these receptors and their link with eosinophilic inflammation in paranasal sinus diseases. We aimed with this study to investigate the tissue expression of leukotrienes and prostaglandin E2 receptors in chronic rhinosinusitis patients and the link of this regulation with eosinophilic inflammation. METHODS: Samples were prepared from nasal tissue of patients with chronic rhinosinusitis without nasal polyps (CRS, n = 11), with nasal polyps (CRS-NP, n = 13) and healthy subjects (Controls, n = 6). mRNA expression of CysLT(1), CysLT(2), BLT(1), BLT(2), E-prostanoid receptors (EP(1), EP(2), EP(3), EP(4)) and sol-IL-5Rα was determined by real-time PCR. Concentrations of PGE2, LTC4/D4/E4, LTB4 and sol-IL-5Rα were determined by ELISA and of ECP by ImmunoCap. Protein expression and tissue localization of eicosanoid receptors and activated eosinophils were evaluated by immunohistochemistry. RESULTS: CysLT(1 )mRNA expression was significantly increased in CRS-NP compared to CRS and controls, and CRS compared to controls, whereas CysLT(2 )mRNA was enhanced in both CRS groups without differences between them. Levels of both receptors correlated to the number of activated eosinophils, sol-IL-5Rα, ECP and LTC(4)/D(4)/E(4 )concentrations in the disease groups. PGE(2 )protein concentrations and prostanoid receptors EP(1 )and EP(3 )were down-regulated in the CRS-NP tissue vs. CRS and controls, whereas EP(2 )and EP(4 )expression was enhanced in CRS and CRS-NP patients vs. controls. No differences in BLT receptors were observed between patients and controls. CONCLUSION: CyLTs receptors are up-regulated in nasal polyp tissue and their expression correlate with eosinophilic inflammation supporting previous results. Eicosanoid receptors mRNA pattern observed suggests that down-regulation of EP(1 )and EP(3 )in CRS-NP and up-regulation EP(2 )and EP(4 )in CRS and CRS-NP groups may have some role in the development of the diseases and their regulation may not be directly linked to eosinophil activation but involve post-transcriptional events mainly related to other inflammatory cell sources
Regeneration of Graft Livers and Limited Contribution of Extrahepatic Cells After Partial Liver Transplantation in Humans
Background Liver regeneration is still not fully understood. Partial liver transplantation (LT) can provide the opportunity to investigate the mechanisms of liver regeneration, including the contribution of extrahepatic cells to liver regeneration. Methods Of 61 patients transplanted with partial liver graft between August 1997 and October 2006, 56 patients were studied, including 49 adults and 7 children. Sequential computed tomography volumetric analysis was performed for volume measurement, while proliferating cell nuclear antigen (PCNA) labeling index was investigated for liver cell proliferation in nonprotocol liver biopsy specimens. In addition, 15 male recipients who had female liver grafts were investigated in order to detect Y chromosomes as extrahepatic cells in nonprotocol liver biopsy specimens. Results Graft volume per standard liver volume was markedly increased after adult-to-adult living-donor (LD) LT. In pediatric transplants, there was no volume increase over time. PCNA labeling index was vigorous in adult-to-adult LDLT in the early period after LDLT. No Y chromosome was evident in hepatocytes from female-donor male-recipient grafts during or after liver regeneration. However, in the cases of failing grafts of this type, many Y-chromosome-positive cells were observed in the graft liver. The character of those cells was CD34(−), CK9(−), hepatocyte-specific antigen(−), and CD68(+/−). Conclusion In adult-to-adult LDLT, vigorous liver regeneration occurs in the graft liver, demonstrated by not only volumetric but cell kinetic analysis. Involvement of extrahepatic cells in normal liver regeneration seems limited
Young and Intermediate-age Distance Indicators
Distance measurements beyond geometrical and semi-geometrical methods, rely
mainly on standard candles. As the name suggests, these objects have known
luminosities by virtue of their intrinsic proprieties and play a major role in
our understanding of modern cosmology. The main caveats associated with
standard candles are their absolute calibration, contamination of the sample
from other sources and systematic uncertainties. The absolute calibration
mainly depends on their chemical composition and age. To understand the impact
of these effects on the distance scale, it is essential to develop methods
based on different sample of standard candles. Here we review the fundamental
properties of young and intermediate-age distance indicators such as Cepheids,
Mira variables and Red Clump stars and the recent developments in their
application as distance indicators.Comment: Review article, 63 pages (28 figures), Accepted for publication in
Space Science Reviews (Chapter 3 of a special collection resulting from the
May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space
Age
Impaired Insulin Secretion and Enhanced Insulin Sensitivity in Cholecystokinin-Deficient Mice
Leptin Receptor Signaling and Action in the Central Nervous System
The increasing incidence of obesity in developed nations represents an ever‐growing challenge to health care by promoting diabetes and other diseases. The discovery of the hormone, leptin, a decade ago has facilitated the acquisition of new knowledge regarding the regulation of energy balance. A great deal remains to be discovered regarding the molecular and anatomic actions of leptin, however. Here, we discuss the mechanisms by which leptin activates intracellular signals, the roles that these signals play in leptin action in vivo, and sites of leptin action in vivo. Using “reporter” mice, in which LRb‐expressing (long form of the leptin receptor) neurons express the histological marker, β‐galactosidase, coupled with the detection of LRb‐mediated signal transducer and activator of transcription 3 signaling events, we identified LRb expression in neuronal populations both within and outside the hypothalamus. Understanding the regulation and physiological function of these myriad sites of central leptin action will be a crucial next step in the quest to understand mechanisms of leptin action and energy balance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/93692/1/oby.2006.310.pd
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