X-Ray and Near-Infrared Observations of GX 339-4 in the Low/Hard State with Suzaku and IRSF

X-ray and near-infrared ($J$-$H$-$K_{\rm s}$) observations of the Galactic black hole binary GX 339--4 in the low/hard state were performed with Suzaku and IRSF in 2009 March. The spectrum in the 0.5--300 keV band is dominated by thermal Comptonization of multicolor disk photons, with a small contribution from a direct disk component, indicating that the inner disk is almost fully covered by hot corona with an electron temperature of $\approx$175 keV. The Comptonizing corona has at least two optical depths, $\tau \approx 1,0.4$. Analysis of the iron-K line profile yields an inner disk radius of $(13.3^{+6.4}_{-6.0}) R_{\rm g}$ ($R_{\rm g}$ represents the gravitational radius $GM/c^2$), with the best-fit inclination angle of $\approx50^\circ$. This radius is consistent with that estimated from the continuum fit by assuming the conservation of photon numbers in Comptonization. Our results suggest that the standard disk of GX 339--4 is likely truncated before reaching the innermost stable circular orbit (for a non rotating black hole) in the low/hard state at $\sim$1% of the Eddington luminosity. The one-day averaged near-infrared light curves are found to be correlated with hard X-ray flux with $F_{\rm Ks} \propto F_{\rm X}^{0.45}$. The flatter near infrared $\nu F_{\nu}$ spectrum than the radio one suggests that the optically thin synchrotron radiation from the compact jets dominates the near-infrared flux. Based on a simple analysis, we estimate the magnetic field and size of the jet base to be $5\times10^4$ G and $6\times 10^8$ cm, respectively. The synchrotron self Compton component is estimated to be approximately 0.4% of the total X-ray flux.Comment: 17pages, 15 figures, accepted for publication in PASJ (Suzaku and MAXI Special Issue

On-Orbit Verification of Luminance Based Target Tracking and Faint Body Extractions by a Small Telescope on the World\u27s First Micro-Interplanetary Space Probe

In recent years, low cost and quick development of very small satellites ranging from CubeSats of 1 kg to micro-satellites of approximately 50 kg have allowed advances in space development and application. Although most of these satellites are in Earth orbits, a small spacecraft for deep-space missions has been developed and launched for the first time in the world. The Proximate Object Close Flyby with Optical Navigation (PROCYON) micro-interplanetary spacecraft, developed by the University of Tokyo and the Japan Aerospace Exploration Agency, was launched in December 2014 as one of the secondary payloads of the asteroid sample return spacecraft Hayabusa-2. The main mission of PROCYON is to demonstrate critical technologies of 50-kg-class interplanetary spacecraft exploration such as communication, attitude control, thermal control, and power generation. Furthermore, advanced missions of PROCYON enable a close flyby of an asteroid at an altitude of approximately several dozen kilometers and the capture of high-resolution images of approximately several meters per pixel by a telescope. In the flyby missions, the change of the target direction vector from the spacecraft to the asteroid is steeper than that of past flyby interplanetary probes. Thus, the spacecraft could not keep the asteroid in a telescope\u27s field of view only by performing an attitude maneuver of the entire body. To overcome this attitude maneuverability problem, a small and line-of-sight controllable telescope using a rotating mirror was developed and implemented on PROCYON. Due to the system constraint of the micro-spacecraft, this telescope should also be used for optical navigation by the faint asteroid images performed before several days of closest approach. The telescope is very lightweight, approximately 680 g. Moreover, its exposure time range is very high; thus, it can capture images of very dark astronomical bodies of approximately 12 magnitudes to supply information for trajectory correction maneuvers as well as bright bodies observed at a short distance during the close flyby. The results of experiments in the interplanetary orbit are shown in the presentation. Several 12 magnitude stars were identified from the images captured in orbit by utilizing the noise reduction techniques. This result complies with mission requirement of the optical navigation of PROCYON to extract the target images at least three days before closest approach. During the Earth approaching period, a visual feedback tracking experiment was performed utilizing the reflected light from the Earth. Time history of the rotation angle of the telescope shows the direction determination accuracy of the target body by the luminance center extraction using on-board image processing system. The know-how of the optical system of PROCYON enables a variety of missions in the interplanetary field performed by micro-spacecraft

Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study

Todo K., Okazaki S., Doijiri R., et al. Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study. Journal of the American Heart Association 13, e031508 (2024); https://doi.org/10.1161/JAHA.123.031508.BACKGROUND: Atrial fibrillation (AF) is known to be a strong risk factor for stroke. However, the risk of stroke recurrence in patients with cryptogenic stroke with AF detected after stroke by an insertable cardiac monitor (ICM) is not well known. We sought to evaluate the risk of ischemic stroke recurrence in patients with cryptogenic stroke with and without ICM-detected AF. METHODS AND RESULTS: We retrospectively reviewed patients with cryptogenic stroke who underwent ICM implantation at 8 stroke centers in Japan. Cox regression models were developed using landmark analysis and time-dependent analysis. We set the target sample size at 300 patients based on our estimate of the annualized incidence of ischemic stroke recurrence to be 3% in patients without AF detection and 9% in patients with AF detection. Of the 370 patients, 121 were found to have AF, and 110 received anticoagulation therapy after AF detection. The incidence of ischemic stroke recurrence was 4.0% in 249 patients without AF detection and 5.8% in 121 patients with AF detection (P=0.45). In a landmark analysis, the risk of ischemic stroke recurrence was not higher in patients with AF detected ≤90 days than in those without (hazard ratio, 1.47 [95% CI, 0.41–5.28]). In a time-dependent analysis, the risk of ischemic stroke recurrence did not increase after AF detection (hazard ratio, 1.77 [95% CI, 0.70–4.47]). CONCLUSIONS: The risk of ischemic stroke recurrence in patients with cryptogenic stroke with ICM-detected AF, 90% of whom were subsequently anticoagulated, was not higher than in those without ICM-detected AF

Functional MRIを用いた視中枢および眼球運動中枢の研究

科学研究費補助金研究成果報告書研究種目: 基盤研究(B)研究期間: 1996～1998課題番号: 08457463研究代表者: 西田 保裕（滋賀医科大学・医学部・講師）研究分担者: 可児 一孝（滋賀医科大学・医学部・教授）研究分担者: 稲富 昭太（滋賀医科大学・医学部・名誉教授）研究分担者: 永田 啓（滋賀医科大学・医学部・講師）研究分担者: 中村 二郎（滋賀医科大学・医学部・助手）研究分担者: 青木 佳子（滋賀医科大学・医学部・助手）研究分担者: 林 理（滋賀医科大学・医学部・助手）研究分担者: 吉田 健一（滋賀医科大学・医学部・助手

STUDY OF STRABISMUS USING A VIRTUAL REALITY SYSTEM

科学研究費補助金研究成果報告書研究種目: 一般研究(B)研究期間: 1993～1994課題番号: 05454471研究代表者: 可児 一孝（滋賀医科大学・医学部・教授）研究分担者: 山出 新一（滋賀医科大学・医学部・助教授）研究分担者: 西田 保裕（滋賀医科大学・医学部・講師）研究分担者: 永田 啓（滋賀医科大学・医学部・助手）研究分担者: 中村 二郎（滋賀医科大学・医学部・助手）研究分担者: 佐々本 研二（滋賀医科大学・医学部・講師）研究分担者: 稲富 昭太（滋賀医科大学・医学部・名誉教授

A trial manufacturing of a fundus perimeter by which the target automatically pursue eye movement

科学研究費補助金研究成果報告書研究種目: 基盤研究(A)研究期間: 1995～1997課題番号: 07557262研究代表者: 可児 一孝（滋賀医科大学・医学部・教授）研究分担者: 稲富 昭太（滋賀医科大学・医学部・名誉教授）研究分担者: 山出 新一（滋賀医科大学・医学部・助教授）研究分担者: 西田 保裕（滋賀医科大学・医学部・講師）研究分担者: 永田 啓（滋賀医科大学・医学部・講師）研究分担者: 中村 二郎（滋賀医科大学・医学部・助手）研究分担者: 黄野 桃世（滋賀医科大学・医学部・助手）研究分担者: 吉田 健一（滋賀医科大学・医学部・助手）研究分担者: 林 理（滋賀医科大学・医学部・助手）研究分担者: 山田 重喜（滋賀医科大学・医学部・助手

Detection of substrate binding of a collagen-specific molecular chaperone HSP47 in solution using fluorescence correlation spectroscopy

Heat shock protein 47 kDa (HSP47), an ER-resident and collagen-specific molecular chaperone, recognizes collagenous hydrophobic amino acid sequences (Gly-Pro-Hyp) and assists in secretion of correctly folded collagen. Elevated collagen production is correlated with HSP47 expression in various diseases, including fibrosis and keloid. HSP47 knockdown ameliorates liver fibrosis by inhibiting collagen secretion, and inhibition of the interaction of HSP47 with procollagen also prevents collagen secretion. Therefore, a high-throughput system for screening of drugs capable of inhibiting the interaction between HSP47 and collagen would aid the development of novel therapies for fibrotic diseases. In this study, we established a straightforward method for rapidly and quantitatively measuring the interaction between HSP47 and collagen in solution using fluorescence correlation spectroscopy (FCS). The diffusion rate of HSP47 labeled with Alexa Fluor 488 (HSP47-AF), a green fluorescent dye, decreased upon addition of type I or III collagen, whereas that of dye-labeled protein disulfide isomerase (PDI) or bovine serum albumin (BSA) did not, indicating that specific binding of HSP47 to collagen could be detected using FCS. Using this method, we calculated the dissociation constant of the interaction between HSP47 and collagen. The binding ratio between HSP47-AF and collagen did not change in the presence of sodium chloride, confirming that the interaction was hydrophobic in nature. In addition, we observed dissociation of collagen from HSP47 at low pH and re-association after recovery to neutral pH. These observations indicate that this system is appropriate for detecting the interaction between HSP47 and collagen, and could be applied to high-throughput screening for drugs capable of suppressing and/or curing fibrosis