Night-Time Color Imaging with High Resolution from a 35 kg Microsatellite

Canon Electronics Inc. developed its third microsatellite to demonstrate optical systems and in-house developed components in orbit. The 35 kg microsatellite CE-SAT-IIB can capture night-time color images of moon lit earth surface as well as city lights with a newly-designed camera using an ultra-high sensitivity image sensor developed by Canon. CE-SAT-IIB was launched in October 2020 as a payload on the Rocket LabsElectron15and has been performing experiments to validate optical systems and the bus using in-house components. CE-SAT-IIB has three types of cameras. The first camera is a 20 cm Cassegrain telescope with the ultra-high sensitivity detector previously described. Exposure is controllable through shutter speed, CMOS gain, and ND filters. The sensitivity is equivalent to approximately 4 million in ISO by maximizing the gain and detaching all the ND filters. Focus can be adjusted via a stepper motor on the detector, and observable area is approximately 3.5 km x 2.3 km on the ground with theoretical ground sampling distance (GSD) 5m from a 500 km orbit. The second camera is 8.7 cm Cassegrain telescope with a commercial off-the-shelf (COTS)detector using24.2 MP CMOS sensor. Exposure is controllable through shutter speed and ISO, and focus can be adjusted by controlling the temperature of the telescope. The Effective focal length of this camera is809 mm, which enables to capture ground images of approximately 5.6 km x 3.7kmwith theoretical GSD2.3m. The third camera is also a COTS compact digital camera. Exposure is controllable through shutter speed, ISO, and F-number. In addition, adjustable focal length provides wide range of images from approximately 215 km x 145 km to 645 km x 435km in ground distance. The bus of CE-SAT-IIB mainly consists of in-house components such as sun aspect sensors, a geomagnetic aspect sensor, an inertial reference unit, a star tracker, magnetorquers, and reaction wheels to shorten the delivery time and guarantee quality for mass-manufacturing. All of these components have worked as designed in orbit, and the satellite has achieved 3-axis attitude control such as ground tracking, and inertial pointing. Canon Electronics has demonstrated three sizes of Cassegrain telescopes and validated two size of bus systems by CE-SAT-I and CE-SAT-IIB. We are going to start providing high quality telescopes, detectors, bus systems, components, and integrated satellite systemin a short delivery time

Reduction of streak artifacts caused by low photon counts utilizing an image-based forward projection in computed tomography

13301甲第5395号博士（保健学）博士論文本文Full博士論文本文Full 以下に掲載：Computers in Biology and Medicine 135 pp.1-13/ 104583 2021. Elsevier. 共著者：Shinji Niwa, Katsuhiro Ichikawa, Hiroki Kawashima, Tadanori Takata, Shuhei Minami, Wataru Mitsu

Rex1/Zfp42 is dispensable for pluripotency in mouse ES cells

Research articl

Expressions of the cytochrome P450 monooxygenase gene Cyp4g1 and its homolog in the prothoracic glands of the fruit fly Drosophila melanogaster (Diptera: Drosophilidae) and the silkworm Bombyx mori (Lepidoptera: Bombycidae)

Here we describe the expression profiles of the cytochrome P450 monooxygenase gene Cyp4g1 in the fruit fly, Drosophila melanogaster Meigen, and its homolog in the silkworm, Bombyx mori L. We identified Cyp4g1 by a microarray analysis to examine the expression levels of 86 predicted D. melanogaster P450 genes in the ring gland that contains the prothoracic gland (PG), an endocrine organ responsible for synthesizing ecdysteroids. B. mori Cyp4g25 is a closely related homolog of D. melanogaster Cyp4g1 and is also expressed in the PG. A developmental expression pattern of Cyp4g25 in the PG is positively correlated with a fluctuation in hemolymph ecdysteroid titer in the late stage of the final instar. Moreover, the expression of Cyp4g25 in cultured PGs is significantly induced by the addition of prothoracicotropic hormone (PTTH), a neuropeptide hormone that stimulates the synthesis and release of ecdysone. We propose that Cyp4g1 and Cyp4g25 are the candidates that play a role in regulating PG function and control ecdysteroid production and/or metabolism during insect development

Identification of Pou5f1, Sox2, and Nanog downstream target genes with statistical confidence by applying a novel algorithm to time course microarray and genome-wide chromatin immunoprecipitation data

<p>Abstract</p> <p>Background</p> <p>Target genes of a transcription factor (TF) <it>Pou5f1 </it>(<it>Oct3/4 </it>or <it>Oct4</it>), which is essential for pluripotency maintenance and self-renewal of embryonic stem (ES) cells, have previously been identified based on their response to <it>Pou5f1 </it>manipulation and occurrence of Chromatin-immunoprecipitation (ChIP)-binding sites in promoters. However, many responding genes with binding sites may not be direct targets because response may be mediated by other genes and ChIP-binding site may not be functional in terms of transcription regulation.</p> <p>Results</p> <p>To reduce the number of false positives, we propose to separate responding genes into groups according to direction, magnitude, and time of response, and to apply the false discovery rate (FDR) criterion to each group individually. Using this novel algorithm with stringent statistical criteria (FDR < 0.2) to a compendium of published and new microarray data (3, 6, 12, and 24 hr after <it>Pou5f1 </it>suppression) and published ChIP data, we identified 420 tentative target genes (TTGs) for <it>Pou5f1</it>. The majority of TTGs (372) were down-regulated after <it>Pou5f1 </it>suppression, indicating that the <it>Pou5f1 </it>functions as an activator of gene expression when it binds to promoters. Interestingly, many activated genes are potent suppressors of transcription, which include polycomb genes, zinc finger TFs, chromatin remodeling factors, and suppressors of signaling. Similar analysis showed that <it>Sox2 </it>and <it>Nanog </it>also function mostly as transcription activators in cooperation with <it>Pou5f1</it>.</p> <p>Conclusion</p> <p>We have identified the most reliable sets of direct target genes for key pluripotency genes – <it>Pou5f1</it>, <it>Sox2</it>, and <it>Nanog</it>, and found that they predominantly function as activators of downstream gene expression. Thus, most genes related to cell differentiation are suppressed indirectly.</p

Temporal resolution measurement of 128-slice dual source and 320-row area detector computed tomography scanners in helical acquisition mode using the impulse method

Purpose: To analyse the temporal resolution (TR) of modern computed tomography (CT) scanners using the impulse method, and assess the actual maximum TR at respective helical acquisition modes. Methods: To assess the actual TR of helical acquisition modes of a 128-slice dual source CT (DSCT) scanner and a 320-row area detector CT (ADCT) scanner, we assessed the TRs of various acquisition combinations of a pitch factor (P) and gantry rotation time (R). Results: The TR of the helical acquisition modes for the 128-slice DSCT scanner continuously improved with a shorter gantry rotation time and greater pitch factor. However, for the 320-row ADCT scanner, the TR with a pitch factor of 1.0, it was approximately one half of the gantry rotation time. The maximum TR values of single- and dual-source helical acquisition modes for the 128-slice DSCT scanner were 0.138 (R/. P = 0.285/1.5) and 0.074. s (R/. P = 0.285/3.2), and the maximum TR values of the 64. ×. 0.5- and 160. ×. 0.5-mm detector configurations of the helical acquisition modes for the 320-row ADCT scanner were 0.120 (R/. P = 0.275/1.375) and 0.195. s (R/. P = 0.3/0.6), respectively. Conclusion: Because the TR of a CT scanner is not accurately depicted in the specifications of the individual scanner, appropriate acquisition conditions should be determined based on the actual TR measurement. © 2016 Associazione Italiana di Fisica Medica

Glutathione Related Enzyme Activities in Spontaneous Hypertensive Rat Heart

It has been reported that oxygen radicals are involved in the development of tissue injury in hypertension. To prevent o xidative stress, there are antioxidant systems inside the cells such as superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reducatase (GR), catalase (CAT) and glutathione S-transferase (GST). In this study changes in these antioxidant activities were estimated in the outer wall of the left ventricles from spontaneously hypertensive rats (SHR), stroke prone SHR (SHRSP) and normal Wister Kyoto rats (WKY). The activities of manganese-superoxide dismutase (Mn-SOD), which localizes in mitochondria and GST were lower in the left ventricles of SHR and SHRSP compared to those in WKY. Slight decrease in the GPX activity was observed in the left ventricles from SHR and SHRSP. On the other hand, the activity of GR and catalase was not different in them. The effect of Nicardipine, a calcium channel blocker, on these antioxidant activities was also esimated. Treatment of these rats with nicardipine (150 mg/kg/day) for 4 weeks improved blood pressure, from 176ﾂｱ10 mmHg to 140ﾂｱ8 mmHg in SHR (n = 5), from 201ﾂｱ11 mmHg to 167ﾂｱ5 in SHRSP (n = 5), respectively, and restored the activities of Mn-SOD, GST and GPX. Collectively, these results suggest that oxidative stress in hypertensive rat heart causes supression of antioxidant activities, which may contribute to myocardical injury, and nicardipine plays a cardioprotective role to reduce the oxidative stress in hypertensive heart

Receptor Autoradiographic Analysis of Muscarinic Receptors in the Rat Atrioventricular Node

We carried out investigations on muscarinic acetylcholine receptors (m-AChR) in the rat heart, including the atrioventricular (AV) node. The related tissue sections were incubated with 3H-quinuclidinyl benzilate (3H-QNB), then autoradiography and an image analysis coupled with computer-assisted microdensitometry were done. A single type of specific and high affinity binding sites of 3H-QNB was found to be highly concentrated in the AV node, the maximum binding capacity (Bmax) being 1.4 pmol/mg protein and with a dissociation constant (Kd) of 0.5 nM. The density and affinity of the binding to the AV node were the highest, when compared with findings in the atrium (interatrial septum) and ventricle (interventricular septum). The binding was competitively displaced by AF-DX 116, a selective antagonist for the M2 AChR subtype, with a high affinity, whereas pirenzepine, an antagonist for the M1 AChR subtype was much less potent in displacing the binding. Therefore, vagal-cholinergic stimulation presumably plays a significant role in functions of the rat AV node, probably by interacting with the specific, high affinity M2 AChR subtype