1,954 research outputs found
Simultaneous VLBI Astrometry of H2O and SiO Masers toward the Semiregular Variable R Crateris
We obtained, for the first time, astrometrically registered maps of the 22.2
GHz H2O and 42.8, 43.1, and 86.2 GHz SiO maser emission toward the semiregular
b-type variable (SRb) R Crateris, at three epochs (2015 May 21, and 2016
January 7 and 26) using the Korean Very-long-baseline Interferometry Network.
The SiO masers show a ring-like spatial structure, while the H2O maser shows a
very asymmetric one-side outflow structure, which is located at the southern
part of the ring-like SiO maser feature. We also found that the 86.2 GHz SiO
maser spots are distributed in an inner region, compared to those of the 43.1
GHz SiO maser, which is different from all previously known distributions of
the 86.2 GHz SiO masers in variable stars. The different distribution of the
86.2 GHz SiO maser seems to be related to the complex dynamics caused by the
overtone pulsation mode of the SRb R Crateris. Furthermore, we estimated the
position of the central star based on the ring fitting of the SiO masers, which
is essential for interpreting the morphology and kinematics of a circumstellar
envelope. The estimated stellar coordinate corresponds well to the position
measured by Gaia
Clinical characteristics of 2009 pandemic influenza A (H1N1) infection in children and the performance of rapid antigen test
PurposeIn autumn 2009, the swine-origin influenza A (H1N1) virus spread throughout South Korea. The aims of this study were to determine the clinical characteristics of children infected by the 2009 H1N1 influenza A virus, and to compare the rapid antigen and real-time polymerase chain reaction (PCR) tests.MethodsWe conducted a retrospective review of patients ≥18 years of age who presented to Soonchunhyang University Hospital in Seoul with respiratory symptoms, including fever, between September 2009 and January 2010. A real-time PCR test was used to definitively diagnose 2009 H1N1 influenza A infection. Medical records of confirmed cases were reviewed for sex, age, and the time of infection. The decision to perform rapid antigen testing was not influenced by clinical conditions, but by individual factors such as economic conditions. Its sensitivity and specificity were evaluated compared to real-time PCR test results.ResultsIn total, 934 patients tested positive for H1N1 by real-time PCR. The highest number of patients (48.9%) was diagnosed in November. Most patients (48.2%) were aged between 6 and 10 years. Compared with the H1N1 real-time PCR test results, the rapid antigen test showed 22% sensitivity and 83% specificity. Seventy-eight patients were hospitalized for H1N1 influenza A virus infection, and fever was the most common symptom (97.4%).ConclusionFor diagnosis of 2009 H1N1 influenza A virus infection, the rapid antigen test was inferior to the real-time PCR test in both sensitivity and specificity. This outcome suggests that the rapid antigen test is inappropriate for screening
Glutathione S-transferase pi (GST-pi) inhibition and anti-inflammation activity of the ethyl acetate extract of Streptomyces sp. strain MJM 8637
AbstractTo investigate the anti-cancer properties of soil-borne actinobacteria, MJM 8637, the glutathione S-transferase pi (GST-pi) assay, anti-tumor necrosis factor (TNF)-α assay, the level of antioxidant potential by DPPH radical scavenging activity, NO scavenging activity, and ABTS radical scavenging activity in ethyl acetate extract were determined. The 16S rDNA sequencing analysis revealed that Streptomyces sp. strain MJM 8637, which was isolated from Hambak Mountain, Korea, has 99.5% similarity to Streptomyces atratus strain NBRC 3897. The physiological and the morphological characteristics of the strain MJM 8637 were also identified. The ethyl acetate extract of MJM 8637 inhibited TNF-α production approximately 61.8% at concentration 100μg/ml. The IC50 value of the strain MJM 8637 extract on GST-pi was identified to be 120.2±1.6μg/ml. In DPPH, NO, and ABTS radical scavenging assays, the IC50 values of the strain MJM 8637 extract were found to be 977.2μg/ml, 1143.7μg/ml, and 454.4μg/ml, respectively. The ethyl acetate extract of the strain MJM 8637 showed 97.2±1.3% of cell viability at 100μg/ml in RAW 264.7 cell viability assay. The results obtained from this study suggest that the ethyl acetate extract of Streptomyces sp. strain MJM 8637 could be considered as a potential source of drug for the cancers that have multidrug resistance with its GST-pi inhibition and anti-inflammation activities, and low cytotoxicity
Catalytic Performance for Hydrocarbon Production from Syngas on the Promoted Co-Based Hybrid Catalysts; Influence of Pt Contents
Fischer-Tropsch synthesis (FTS) reaction from syngas was investigated on the Pt-promoted cobalt-based hybrid catalysts prepared by co-precipitation method in a slurry of ZSM-5 (Si/Al=25). The hybrid catalysts were compared with each other for the different content of Pt as a promoter and are characterized using BET, XRD, H2-TPR and NH3-TPD. Their physicochemical properties were correlated with the activity and selectivity of the catalysts. As results, all hybrid catalysts show the C5-C9 yield (%) higher than that of Co-Al2O3/ZSM-5 catalyst. The Pt-promoted hybrid catalysts were found to be more promising towards production of the hydrocarbons of gasoline range and over C10.
Asymmetric distributions of H2O and SiO masers towards V627 Cas
We performed simultaneous observations of the H2O 6(1,6) - 5(2,3) (22.235080
GHz) and SiO v= 1, 2, J = 1 - 0, SiO v = 1, J = 2 - 1, 3 - 2 (43.122080,
42.820587, 86.243442, and 129.363359 GHz) masers towards the suspected D-type
symbiotic star, V627 Cas, using the Korean VLBI Network. Here, we present
astrometrically registered maps of the H2O and SiO v = 1, 2, J = 1 - 0, SiO v =
1, J = 2 - 1 masers for five epochs from January 2016 to June 2018.
Distributions of the SiO maser spots do not show clear ring-like structures,
and those of the H2O maser are biased towards the north-north-west to west with
respect to the SiO maser features according to observational epochs. These
asymmetric distributions of H2O and SiO masers are discussed based on two
scenarios of a bipolar outflow and the presence of the hot companion, a white
dwarf, in V627 Cas. We carried out ring fitting of SiO v = 1, and v = 2 masers
and estimated the expected position of the cool red giant. The ring radii of
the SiO v = 1 maser are slightly larger than those of the SiO v = 2 maser, as
previously known. Our assumption for the physical size of the SiO maser ring of
V627 Cas to be the typical size of a SiO maser ring radius (\sim4 au) of red
giants yields the distance of V627 Cas to be \sim1 kpc.Comment: 7 pages, 4 figures, 1 table, Published in MNRA
Selective Uterine Artery Embolization for Management of Interstitial Ectopic Pregnancy
Interstitial ectopic pregnancy is a rare condition of pregnancy and may be very dangerous if not identified and treated urgently. We report a case of successful treatment of an interstitial pregnancy using selective uterine artery embolization. A 27-year-old woman with interstitial pregnancy was treated by uterine artery embolization after failure of systemic methotrexate treatment. Her serum beta-human chorionic gonadotropin (β-hCG) was undetectable one month after the therapeutic embolization and transvaginal sonography 31 days after embolization showed normal endometrium and cornu. The patient achieved a normal pregnancy eight months after embolization
A Rare Case of Radial Arteriovenous Fistula After Coronary Angiography
The percutaneous transfemoral approach has been routinely used for cardiac catheterization and coronary angioplasty. Local vascular complications following angioplasty are seen in 5% to 10% of patients, especially in those who need prolonged anticoagulation. Transradial access for coronary procedures dramatically reduces access site complications. We report a rare case of radial arteriovenous fistula, which developed after coronary angiography perfomed using the transradial approach
A Rare Case of Radial Arteriovenous Fistula After Coronary Angiography
The percutaneous transfemoral approach has been routinely used for cardiac catheterization and coronary angioplasty. Local vascular complications following angioplasty are seen in 5% to 10% of patients, especially in those who need prolonged anticoagulation. Transradial access for coronary procedures dramatically reduces access site complications. We report a rare case of radial arteriovenous fistula, which developed after coronary angiography perfomed using the transradial approach
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