165 research outputs found
Application of X-Ray Clumpy Torus Model (XCLUMPY) to 10 Obscured Active Galactic Nuclei Observed with Suzaku and NuSTAR
We apply XCLUMPY, an X-ray spectral model from a clumpy torus in an active
galactic nucleus (AGN), to the broadband X-ray spectra of 10 obscured AGNs
observed with both Suzaku and NuSTAR. The infrared spectra of these AGNs were
analyzed with the CLUMPY code. Since XCLUMPY adopts the same clump distribution
as that in the CLUMPY, we can directly compare the torus parameters obtained
from the X-ray spectra and those from the infrared ones. The torus angular
widths determined from the infrared spectra () are
systematically larger than those from the X-ray data ();
the difference () correlates with the
inclination angle determined from the X-ray spectrum. These results can be
explained by the contribution from dusty polar outflows to the observed
infrared flux, which becomes more significant at higher inclinations (more
edge-on views). The ratio of the hydrogen column density and V-band extinction
in the line of sight absorber shows large scatter (1 dex) around the
Galactic value, suggesting that a significant fraction of AGNs have dust-rich
circumnuclear environments.Comment: 17 pages, 3 figures, accepted for publication in Ap
The DNA methyltransferase Dnmt1 directly interacts with the SET and RING finger-associated (SRA) domain of the multifunctional protein Uhrf1 to facilitate accession of the catalytic center to hemi-methylated DNA
This research was originally published in Journal of Biological Chemistry. Ahmet Can Berkyurek, Isao Suetake, Kyohei Arita, Kohei Takeshita, Atsushi Nakagawa, Masahiro Shirakawa and Shoji Tajima. The DNA methyltransferase Dnmt1 directly interacts with the SET and RING finger-associated (SRA) domain of the multifunctional protein Uhrf1 to facilitate accession of the catalytic center to hemi-methylated DNA. Journal of Biological Chemistry. 2014; 289, 379-386. © the American Society for Biochemistry and Molecular Biology
Insights on the Sun birth environment in the context of star-cluster formation in hub-filament systems
Cylindrical molecular filaments are observed to be the main sites of Sun-like
star formation, while massive stars form in dense hubs, at the junction of
multiple filaments. The role of hub-filament configurations has not been
discussed yet in relation to the birth environment of the solar system and to
infer the origin of isotopic ratios of Short-Lived Radionuclides (SLR, such as
Al) of Calcium-Aluminum-rich Inclusions (CAIs) observed in meteorites.
In this work, we present simple analytical estimates of the impact of stellar
feedback on the young solar system forming along a filament of a hub-filament
system. We find that the host filament can shield the young solar system from
the stellar feedback, both during the formation and evolution of stars (stellar
outflow, wind, and radiation) and at the end of their life (supernovae). We
show that the young solar system formed along a dense filament can be enriched
with supernova ejecta (e.g., Al) during the formation timescale of CAIs.
We also propose that the streamers recently observed around protostars may be
channeling the SLR-rich material onto the young solar system. We conclude that
considering hub-filament configurations as the birth environment of the Sun is
important when deriving theoretical models explaining the observed properties
of the solar system.Comment: Accepted for publication in The Astrophysical Journal Letter
Successful Endoscopic Injection Sclerotherapy of High-Risk Gastroesophageal Varices in a Cirrhotic Patient with Hemophilia A
A 68-year-old man with hemophilia A and liver cirrhosis caused by hepatitis C virus was referred to our hospital to receive prophylactic endoscopic treatment for gastroesophageal varices (GOV). He had large, tense, and winding esophageal varices (EV) with cherry red spots extending down to lesser curve, predicting the likelihood of bleeding. Esophageal endoscopic injection sclerotherapy (EIS) was performed with a total 15 mL of 5% ethanolamine oleate with iopamidol (EOI). Radiographic imaging during EIS demonstrated that 5% EOI reached the afferent vein of the varices. He was administered sufficient factor VIII concentrate before and after EIS to prevent massive bleeding from the varices. Seven days after EIS, upper gastrointestinal endoscopy (UGIE) showed that the varices were eradicated almost completely. Eighteen months after EIS, the varices continued to diminish. We report a successful case of safe and effective EIS for GOV in a high-risk cirrhotic patient with hemophilia A
Mineralization of hydroxyapatite upon a unique xanthan gum hydrogel by an alternate soaking process
We previously reported a xanthan gum (Xan) hydrogel showing excellent mechanical properties. Mineralization of hydroxyapatite (Hap) upon the Xan hydrogel would provide a unique biomaterial applicable for bone tissue engineering. Here, we show the mineralization of Hap upon the Xan hydrogel by means of an alternate soaking process. Hap was gradually grown upon the Xan-matrix surface with increasing number of soaking cycles due to the ionic interactions between calcium cations and carboxyl groups. Interestingly, the mineralization induced a microstructure change in the gel-matrix from a layered structure to a porous structure. The mechanical properties of the resulting Hap–Xan composite hydrogels were further investigated by a tensile test, where the Hap–Xan composite hydrogel with an appropriate amount of Hap (Xan/Hap = 2.7) was capable of approximately 370% elongation
EpEX, the soluble extracellular domain of EpCAM, resists cetuximab treatment of EGFR-high head and neck squamous cell carcinoma
Objectives: Cetuximab (Cmab) is a molecularly targeted monoclonal antibody drug for head and neck squamous cell carcinoma (HNSC), although cetuximab resistance is a serious challenge. Epithelial cell adhesion molecule (EpCAM) is an established marker for many epithelial tumors, while the soluble EpCAM extracellular domain (EpEX) functions as a ligand for epidermal growth factor receptor (EGFR). We investigated the expression of EpCAM in HNSC, its involvement in Cmab action, and the mechanism by which soluble EpEX activated EGFR and played key roles in Cmab resistance.
Materials and methods: We first examined EPCAM expression in HNSCs and its clinical significance by searching gene expression array databases. We then examined the effects of soluble EpEX and Cmab on intracellular signaling and Cmab efficacy in HNSC cell lines (HSC-3 and SAS).
Results: EPCAM expression was found to be enhanced in HNSC tumor tissues compared to normal tissues, and the enhancement was correlated with stage progression and prognosis. Soluble EpEX activated the EGFR-ERK signaling pathway and nuclear translocation of EpCAM intracellular domains (EpICDs) in HNSC cells. EpEX resisted the antitumor effect of Cmab in an EGFR expression-dependent manner.
Conclusion: Soluble EpEX activates EGFR to increase Cmab resistance in HNSC cells. The EpEX-activated Cmab resistance in HNSC is potentially mediated by the EGFR-ERK signaling pathway and the EpCAM cleavage-induced nuclear translocation of EpICD. High expression and cleavage of EpCAM are potential biomarkers for predicting the clinical efficacy and resistance to Cmab
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