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The 2-unit size cubesat RAIKO is a nanosatellite developed by Tohoku University and Wakayama University. This paper shows the mission and system specifications. The satellite was released to space on October 4, 2012 from International Space Station, which was the 419-km alt. circular orbit. The techniques for 50-kg microsatellites by Tohoku University are transferred to this satellite, so a lot of functions are included although the power and mass budgets are strongly restricted. The primary missions are the photo storage by different 3 optical sensors, the de-orbit mechanism experiment by expandable thin films, and Ku-band downlink communication experiment. The satellite operation was finished by orbital decay on August 6, 2013. The telemetry data were successful received in total 123 passes, in which total 63 photo images were obtained and maximum 100 kbps (200 ksps) downlink was successful. Using color CMOS camera, gradually separating ISS could be confirmed. From analysis of house-keeping data, the solar generation power in sunshine was 3.38 W (no paddles) to 5.77 W (with paddles) in average, the temperature of onboard computer was in the range of 20.8 to 28.7 deg C, and the battery temperature was 4.2 deg C in average. The real flight data from the 10-month operation will be precious information for future nanosatellite projects. [ABSTRACT FROM AUTHOR]

PRIP‐1 was isolated as a novel inositol 1,4,5‐trisphosphate [Ins(1,4,5)P3] binding protein with a domain organization similar to phospholipase C‐δ1 (PLC‐δ1) but lacking the enzymatic activity. Further studies revealed that the pleckstrin homology (PH) domain of PRIP‐1 is the region responsible for binding Ins(1,4,5)P3. In this study we aimed to clarify the role of PRIP‐1 at the physiological concentration in Ins(1,4,5)P3‐mediated Ca2+ signaling, as we had previously used COS‐1 cells overexpressing PRIP‐1 (Takeuchi et al., 2000, Biochem J 349:357–368). For this purpose we employed PRIP‐1 knock out (PRIP‐1−/−) mice generated previously (Kanematsu et al., 2002, EMBO J 21:1004–1011). The increase in free Ca2+ concentration in response to purinergic receptor stimulation was lower in primary cultured cortical neurons prepared from PRIP‐1−/− mice than in those from wild type mice. The relative amounts of [3H]Ins(1,4,5)P3 measured in neurons labeled with [3H]inositol was also lower in cells from PRIP‐1−/− mice. In contrast, PLC activities in brain cortex samples from PRIP‐1−/− mice were not different from those in the wild type mice, indicating that the hydrolysis of Ins(1,4,5)P3 is enhanced in cells from PRIP‐1−/− mice. In vitro analyses revealed that type1 inositol polyphosphate 5‐phosphatase physically interacted with a PH domain of PRIP‐1 (PRIP‐1PH) and its enzyme activity was inhibited by PRIP‐1PH. However, physical interaction with these two proteins did not appear to be the reason for the inhibition of enzyme activity, indicating that binding of Ins(1,4,5)P3 to the PH domain prevented its hydrolyzation. Together, these results indicate that PRIP‐1 plays an important role in regulating the Ins(1,4,5)P3‐mediated Ca2+ signaling by modulating type1 inositol polyphosphate 5‐phosphatase activity through binding to Ins(1,4,5)P3. © 2004 Wiley‐Liss, Inc. [ABSTRACT FROM AUTHOR]