251 research outputs found
Circularly-Polarized Light Emission from Semiconductor Planar Chiral Photonic Crystal
We proposed and demonstrated a scheme of surface emitting circularly
polarized light source by introducing strong imbalance between left- and
right-circularly polarized vacuum fields in an on-waveguide chiral grating
structure. We observed circularly polarized spontaneous emission from InAs
quantum dots embedded in the wave guide region of a GaAs-based structure.
Obtained degree of polarization reaches as large as 25% at room temperature.
Numerical calculation visualizes spatial profiles of the modification of vacuum
field modes inside the structure with strong circular anisotropy.Comment: REVTeX4.1, 6pages, 3figure
Redox-Sensitive Cysteines Confer Proximal Control of the Molecular Crowding Barrier in the Nuclear Pore
酸化ストレスが細胞の核膜機能を変える機構を解明 --環境に応じて分子の「混み具合」が変わる仕組み--. 京都大学プレスリリース. 2020-12-16.The nuclear pore complex forms a highly crowded selective barrier with intrinsically disordered regions at the nuclear membrane to coordinate nucleocytoplasmic molecular communications. Although oxidative stress is known to alter the barrier function, the molecular mechanism underlying this adaptive control of the nuclear pore complex remains unknown. Here we uncover a systematic control of the crowding barrier within the nuclear pore in response to various redox environments. Direct measurements of the crowding states using a crowding-sensitive FRET (Förster resonance energy transfer) probe reveal specific roles of the nuclear pore subunits that adjust the degree of crowding in response to different redox conditions, by adaptively forming or disrupting redox-sensitive disulfide bonds. Relationships between crowding control and the barrier function of the nuclear pore are investigated by single-molecular fluorescence measurements of nuclear transport. Based on these findings, we propose a proximal control model of molecular crowding in vivo that is dynamically regulated at the molecular level
GLUTATHIONE S-TRANSFERASE PLACENTAL FORM IS A MARKER FOR BILE DUCT CARCINOMA, BUT NOT HEPATOCELLULAR CARCINOMA, IN HUMANS.
Immunohistochemical studies using anti-human glutathione S-transferase placental form (GST-π) rabbit antibody were carried out to investigate various hepatobiliary diseases in humans. Hepatocytes in fetal and adult liver without disease were negatively or positively stained while intra-or extrahepatic bile duct epithelial cells were
positively or strongly positively stained with GST-π. Hepatocytes in regenerated nodules in liver cirrhosis were positively stained. Hepatocellular carcinomas were not strongly positively stained, while cholangiocarcinomas and cancers of the biliary tract were positively or strongly positively stained. These results indicate that GST-π staining is a useful marker for the diagnosis of intra-or extra-hepatic bile duct carcinomas in humans, and that enzyme activity is not phenotypically expressed in hepatocellular carcinomas
Rapid detection of hypoxia-inducible factor-1-active tumours: pretargeted imaging with a protein degrading in a mechanism similar to hypoxia-inducible factor-1alpha
PURPOSE: Hypoxia-inducible factor-1 (HIF-1) plays an important role in malignant tumour progression. For the imaging of HIF-1-active tumours, we previously developed a protein, POS, which is effectively delivered to and selectively stabilized in HIF-1-active cells, and a radioiodinated biotin derivative, (3-(123)I-iodobenzoyl)norbiotinamide ((123)I-IBB), which can bind to the streptavidin moiety of POS. In this study, we aimed to investigate the feasibility of the pretargeting method using POS and (123)I-IBB for rapid imaging of HIF-1-active tumours. METHODS: Tumour-implanted mice were pretargeted with POS. After 24 h, (125)I-IBB was administered and subsequently, the biodistribution of radioactivity was investigated at several time points. In vivo planar imaging, comparison between (125)I-IBB accumulation and HIF-1 transcriptional activity, and autoradiography were performed at 6 h after the administration of (125)I-IBB. The same sections that were used in autoradiographic analysis were subjected to HIF-1alpha immunohistochemistry. RESULTS: (125)I-IBB accumulation was observed in tumours of mice pretargeted with POS (1.6%ID/g at 6 h). This result is comparable to the data derived from (125)I-IBB-conjugated POS-treated mice (1.4%ID/g at 24 h). In vivo planar imaging provided clear tumour images. The tumoral accumulation of (125)I-IBB significantly correlated with HIF-1-dependent luciferase bioluminescence (R=0.84, p<0.01). The intratumoral distribution of (125)I-IBB was heterogeneous and was significantly correlated with HIF-1alpha-positive regions (R=0.58, p<0.0001). CONCLUSION: POS pretargeting with (123)I-IBB is a useful technique in the rapid imaging and detection of HIF-1-active regions in tumours
MOIRCS Deep Survey. VII: NIR Morphologies of Star-forming Galaxies at Redshift z~1
We investigate rest-frame near-infrared (NIR) morphologies of a sample of 139
galaxies with M_{s} >= 1 x 10^{10} M_{sun} at z=0.8-1.2 in the GOODS-North
field using our deep NIR imaging data (MOIRCS Deep Survey, MODS). We focus on
Luminous Infrared Galaxies (LIRGs), which dominate high star formation rate
(SFR) density at z~1, in the sample identified by cross-correlating with the
Spitzer/MIPS 24um source catalog. We perform two-dimensional light profile
fitting of the z~1 galaxies in the Ks-band (rest-frame J-band) with a single
component Sersic model. We find that at z~1, ~90% of LIRGs have low Sersic
indices (n<2.5, similar to disk-like galaxies) in the Ks-band, and those
disk-like LIRGs consist of ~60% of the whole disk-like sample above M_{s} >= 3
x 10^{10} M_{sun}. The z~1 disk-like LIRGs are comparable or ~20% small at a
maximum in size compared to local disk-like galaxies in the same stellar mass
range. If we examine rest-frame UV-optical morphologies using the HST/ACS
images, the rest-frame B-band sizes of the z~1 disk-like galaxies are
comparable to those of the local disk-like galaxies as reported by previous
studies on size evolution of disk-like galaxies in the rest-frame optical band.
Measuring color gradients (galaxy sizes as a function of wavelength) of the z~1
and local disk-like galaxies, we find that the z~1 disk-like galaxies have 3-5
times steeper color gradient than the local ones. Our results indicate that (i)
more than a half of relatively massive disk-like galaxies at z~1 are in violent
star formation epochs observed as LIRGs, and also (ii) most of those LIRGs are
constructing their fundamental disk structure vigorously. The high SFR density
in the universe at z~1 may be dominated by such star formation in disk region
in massive galaxies.Comment: 16 pages, 15 figures, accepted for publication in PASJ. Catalog data
will be available at http://astr.tohoku.ac.jp/MODS/wiki/index.php soo
MALIGNANT ONCOCYTOMA OF THE PARANASAL SINUS
A case of malignant oncocytoma developing in the paranasal sinus of a 37-year-old Japanese man with a habit of heavy smoking is described. The primary tumor was found in the right maxillary sinus with local invasion to the nose and right ethmoidal sinus ; it was composed of nests of large oncocytic cells, with finely granular and eosinophilic cytoplasm, nuclear pleomorphism
and prominent nucleoli, surrounded by proliferation of spindle-shaped cells in some areas. Electron microscopically, the cytoplasm of oncocytic tumor cells was characterized by abundant mitochondria, and immunohistochemical investigation revealed positive binding for antibodies to S-100 protein and α₁-antitrypsin, but a negative reaction for both cytokeratin and vimentin. At autopsy, metastatic nodules of tumor in the lungs, liver and pancreas independently exhibited both oncocytic cell- and sarcomatous cell compartments. This phenomenon is rare, and to the authors' knowledge, this would be histologically an ususual report of malignant oncocytoma with sarcomatous metastatic nodules arising from the paranasal sinus to be described in the literature
Assembly of Massive Galaxies in a High-z Protocluster
We present the results of wide-field deep JHK imaging of the SSA22 field
using MOIRCS instrument equipped with Subaru telescope. The observed field is
112 arcmin^2 in area, which covers the z=3.1 protocluster characterized by the
overdensities of Ly Alpha emitters (LAEs) and Ly Alpha Blobs (LABs). The 5
sigma limiting magnitude is K_{AB} = 24.3. We extract the potential
protocluster members from the K-selected sample by using the multi-band
photometric-redshift selection as well as the simple color cut for distant red
galaxies (DRGs; J-K_{AB}>1.4). The surface number density of DRGs in our
observed fields shows clear excess compared with those in the blank fields, and
the location of the densest area whose projected overdensity is twice the
average coincides with the large-scale density peak of LAEs. We also found that
K-band counterparts with z_{phot} = 3.1 are detected for 75% (15/20) of the
LABs within their Ly Alpha halo, and the 40 % (8/20) of LABs have multiple
components, which gives a direct evidence of the hierarchical multiple merging
in galaxy formation. The stellar mass ofLABs correlates with their luminosity,
isophotal area, and the Ly Alpha velocity widths, implying that the physical
scale and the dynamical motion of Ly Alpha emission are closely related to
their previous star-formation activities. Highly dust-obscured galaxies such as
hyper extremely red objects (HEROs; J-K_{AB}>2.1) and plausible K-band
counterparts of submillimeter sources are also populated in the high density
region.Comment: 21pages, accepted for publication in Astrophysical Journa
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