26 research outputs found
The Hayabusa Spacecraft Asteroid Multi-Band Imaging Camera: AMICA
The Hayabusa Spacecraft Asteroid Multiband Imaging Camera (AMICA) has
acquired more than 1400 multispectral and high-resolution images of its target
asteroid, 25143 Itokawa, since late August 2005. In this paper, we summarize
the design and performance of AMICA. In addition, we describe the calibration
methods, assumptions, and models, based on measurements. Major calibration
steps include corrections for linearity and modeling and subtraction of bias,
dark current, read-out smear, and pixel-to-pixel responsivity variations. AMICA
v-band data were calibrated to radiance using in-flight stellar observations.
The other band data were calibrated to reflectance by comparing them to
ground-based observations to avoid the uncertainty of the solar irradiation in
those bands. We found that the AMICA signal was linear with respect to the
input signal to an accuracy of << 1% when the signal level was < 3800 DN. We
verified that the absolute radiance calibration of the AMICA v-band (0.55
micron) was accurate to 4% or less, the accuracy of the disk-integrated spectra
with respect to the AMICA v-band was about 1%, and the pixel-to-pixel
responsivity (flatfield) variation was 3% or less. The uncertainty in
background zero-level was 5 DN. From wide-band observations of star clusters,
we found that the AMICA optics have an effective focal length of 120.80 \pm
0.03 mm, yielding a field-of-view (FOV) of 5.83 deg x 5.69 deg. The resulting
geometric distortion model was accurate to within a third of a pixel. We
demonstrated an image-restoration technique using the point-spread functions of
stars, and confirmed that the technique functions well in all loss-less images.
An artifact not corrected by this calibration is scattered light associated
with bright disks in the FOV.Comment: 107 pages, 22 figures, 9 tables. will appear in Icaru
Introduction for Fisheries and Aquatic Biology
Chapter I. Aquatic Environment. Ken FURUYA and Ichiro YASUDA : chapter_1.pdfChapter II. Biology and Ecology of Aqua-Shere. Toyoji KANEKO, Katsumi TSUKAMOTO, Atsushi TSUDA, Yuzuru SUZUKI and Katsufumi SATOH : chapter_2.pdfChapter III. Aquatic Resource and Production. Ichiro AOKI, Kazuo OGAWA, Taku YAMAKAWA and Tomoyoshi YOSHINAGA : chapter_3.pdfChapter IV. Chemistry of Aquatic Organism and Their Utilization. Hiroki ABE, Shugo WATABE, Yoshihiro OCHIAI, Shigeru OKADA, Naoko YOSHIKAWA, Yoshiharu KINOSHITA, Gen KANEKO and Shigeki MATSUNAGA : chapter_4.pdfChapter V. Relation between Aqua-Shere and Human Life. Hisashi KUROKURA, Hirohide MATSUSHIMA, Shingo KUROHAGI, Haruko YAMASHITA, Akinori HINO, Kazumasa IKUTA, Satoquo SEINO, Masahiko ARIJI, Ken FURUYA, Junichiro OKAMOTO and Nobuyuki YAGI : chapter_5.pdfPart of "Introduction for Fisheries and Aquatic Biology
SALL3 Interacts with DNMT3A and Shows the Ability To Inhibit CpG Island Methylation in Hepatocellular Carcinoma▿ †
The mechanisms of aberrant CpG island methylation in oncogenesis are not fully characterized. In particular, little is known about the mechanisms of inhibition of CpG island methylation. Here we show that sal-like 3 (SALL3) is a novel inhibitory factor for DNA methyltransferase 3 alpha (DNMT3A). SALL3 binds to DNMT3A by a direct interaction between the double zinc finger motif of SALL3 and the PWWP domain of DNMT3A. SALL3 expression reduces DNMT3A-mediated CpG island methylation in cell culture and in vitro. CpG island methylation is enhanced in SALL3-depleted cells. Consistently, DNMT3A from SALL3-depleted cells increases methyltransferase activity in vitro. Binding of DNMT3A to chromatin is reduced or increased by SALL3 expression or depletion, respectively, accounting for the mechanism by which SALL3 inhibits DNMT3A-mediated CpG island methylation. We also show that SALL3 is inducible by BMP-4 and silenced by associated DNA methylation in hepatocellular carcinoma (HCC). Our results suggest that silencing of SALL3 results in acceleration of DNA methylation in HCC. This functional characterization of SALL3 sheds light on regulatory mechanisms for DNMT3A and provides new strategies to inhibit aberrant methylation in cancer
Light-Regulated mRNA Condensation by a Photosensitive Surfactant Works as a Series Photoswitch of Translation Activity in the Presence of Small RNAs
AzoTAB, a photosensitive azobenzene cationic surfactant,
which
phototriggers translation activity through light-regulated condensation
of mRNA, is added to a translation solution containing several mRNAs,
which can be selectively silenced by specific small RNAs. We find
that gene silencing by small RNAs remains functional regardless of
AzoTAB concentration and UV illumination. In the absence of UV, the
translation of all genes present in the medium is partially to fully
inhibited depending on AzoTAB concentration. In contrast, the application
of a short UV stimulus (365 nm for 1.5 min) results in the selective
photoactivation of genes that are not silenced by small RNA. These
results show that light-regulated condensation by AzoTAB works as
a sequence-independent series photoswitch added to parallel sequence-specific
regulation by small RNAs