2,351 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
CIB1 protects against MPTP-induced neurotoxicity through inhibiting ASK1.
Calcium and integrin binding protein 1 (CIB1) is a calcium-binding protein that was initially identified as a binding partner of platelet integrin αIIb. Although CIB1 has been shown to interact with multiple proteins, its biological function in the brain remains unclear. Here, we show that CIB1 negatively regulates degeneration of dopaminergic neurons in a mouse model of Parkinson\u27s disease using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Genetic deficiency of the CIB1 gene enhances MPTP-induced neurotoxicity in dopaminergic neurons in CIB1(-/-) mice. Furthermore, RNAi-mediated depletion of CIB1 in primary dopaminergic neurons potentiated 1-methyl-4-phenyl pyrinidium (MPP(+))-induced neuronal death. CIB1 physically associated with apoptosis signal-regulating kinase 1 (ASK1) and thereby inhibited the MPP(+)-induced stimulation of the ASK1-mediated signaling cascade. These findings suggest that CIB1 plays a protective role in MPTP/MPP(+)-induced neurotoxicity by blocking ASK1-mediated signaling
Simple Structured DPP-based Small Molecules for High Efficient Organic Photovoltaics
OAIID:oai:osos.snu.ac.kr:snu2013-01/104/0000001236/8SEQ:8PERF_CD:SNU2013-01EVAL_ITEM_CD:104USER_ID:0000001236ADJUST_YN:NEMP_ID:A004558DEPT_CD:445CITE_RATE:0FILENAME:이종원.pdfDEPT_NM:재료공학부EMAIL:[email protected]:
MicroRNAs Are Indispensable for Reprogramming Mouse Embryonic Fibroblasts into Induced Stem Cell-Like Cells
MicroRNAs play a pivotal role in cellular maintenance, proliferation, and differentiation. They have also been implicated to play a key role in disease pathogenesis, and more recently, cellular reprogramming. Certain microRNA clusters can enhance or even directly induce reprogramming, while repressing key proteins involved in microRNA processing decreases reprogramming efficiency. Although microRNAs clearly play important roles in cellular reprogramming, it remains unknown whether microRNAs are absolutely necessary. We endeavored to answer this fundamental question by attempting to reprogram Dicer-null mouse embryonic fibroblasts (MEFs) that lack almost all functional microRNAs using a defined set of transcription factors. Transduction of reprogramming factors using either lentiviral or piggyBac transposon vector into two, independently derived lines of Dicer-null MEFs failed to produce cells resembling embryonic stem cells (ESCs). However, expression of human Dicer in the Dicer-null MEFs restored their reprogramming potential. Our study demonstrates for the first time that microRNAs are indispensable for dedifferentiation reprogramming
Contrast Echo-A Simple Diagnostic Tool for a Coronary Artery Fistula
Coronary artery fistulas have been diagnosed with aortography, coronary angiography, and coronary computed tomography (CT). A large fistula can be occasionally found as a mass lesion on echocardiography but cannot be easily confirmed. Here, we report a new diagnostic approach to coronary artery fistulas using a contrast agent and transthoracic echocardiography. Transthoracic echocardiography of a 46-year-old female suffering from dyspnea revealed suspicious small turbulent flow in the main pulmonary artery. Following infusion of a contrast agent, we found whitish flow in the main pulmonary artery during the diastolic phase, and aortic CT revealed two huge right coronary artery fistulas in the main pulmonary artery. A simple diagnostic approach to a coronary artery fistula using contrast agent helped us confirm the diagnosis because of the typical diastolic whitish flow in the pulmonary artery
The Fundamental Planes of E+A galaxies and GALEX UV-excess early-type galaxies: Revealing their intimate connection
Strong Balmer absorption lines and the lack of Ha and [OII] emission lines
signify that E+As are post-starburst systems. Recent studies suggest that E+As
may undergo the transition from the `blue cloud' to the `red sequence' and
eventually migrate to red sequence ETGs. An observational validation of this
scenario is to identify the intervening galaxy population between E+As and the
red-sequence. Motivated by recent findings with GALEX that a large fraction of
ETGs exhibit UV-excess as a sign of RSF, we investigate the possible connection
of the UV-excess galaxies to E+As. In particular, we examine the FP scaling
relations of the largest sample of ~1,000 E+As selected from the SDSS and
~20,000 morphologically-selected SDSS ETGs with GALEX UV data. The FP
parameters, combined with stellar population indicators, reveal a certain group
of UV-excess ETGs that bridges between E+As and quiescent red galaxies. The
newly identified galaxies are the post-starburst systems characterized by
UV-excess but no Ha emission. This is a conceptual generalisation of "E+A", in
that the Balmer absorption line in the "E+A" definition is replaced with
UV-optical colours that are far more sensitive to RSF than the Balmer lines. We
refer to these UV-excess galaxies as "E+a" galaxies, which stands for
elliptical ("E") galaxies with a minority of A-type ("a") young stars. The
species are either (1) galaxies that experienced starbursts weaker than those
observed in E+As (1~10% of E+As, "mild E+As") or (2) the products of passively
evolved E+As after quenching star formation quite a while ago (~1 Gyr, "old
E+As"). We suggest that the latter type of E+a galaxies represents the most
recent arrival to the red sequence in the final phase of the "E+A" to "red
early-type" transition. (Abridged)Comment: 15 pages, 15 figures, Accepted for publication in MNRA
Relationship between bone mineral density, its associated physiological factors, and tooth loss in postmenopausal Korean women
CT, MR, and Angiography Findings of a Solitary Fibrous Tumor of the Larynx: a Case Report
This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensity area within the mass. For both the CT and MR images, the mass demonstrated heterogeneous enhancement following the administration of contrast material. The angiography showed a hypervascular tumor with heterogeneous persistent staining
- …