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Ptprv is a member of the transmembrane tyrosine phosphatase gene family reported to be expressed in osteoblasts and gonads. To better define the developmental and tissue specificity of Ptprv expression, we generated knock-in mice expressing a nuclear localised β-galactosidase reporter under the control of resident Ptprv regulatory elements. Histochemical staining of Ptprv-nLacZ mice revealed that Ptprv expression is readily detectable in the foetal gonadal ridge of both sexes and in adult gonads where it is localised to Sertoli cells of the testis and celomic epithelial cells of the ovaries. During early limb development, Ptprv expression is prominent in the apical ectodermal ridge of the limb bud. At latter stages of development, Ptprv is predominantly expressed in the perichondrial and periosteal region of long bones, known as the bone collar. In contrast to previous indications from in vitro studies, there is little if any expression in mature osteoblasts in vivo. Analysis of Ptprv mRNA localisation by in situ hybridization in parallel with molecular markers of chondrocytes and osteoblasts confirmed the specific expression of Ptprv in immature bone collar cells. The specificity of Ptprv expression in these cells may be a useful tool to elucidate their role in the transition of skeletal elements from cartilage template to bone. Developmental Dynamics 229:826–834, 2004. © 2004 Wiley-Liss, Inc.

A reset-type Kalman filter for the navigaiton of a winged space vehicle is discussed and a triple rate Kalman filter is proposed to lighten the computation load. The basic idea is to pay attention to the existence of fast and slowly varying state variables and thus to partition the covariance matrix of the conventional Kalman filter into parts of smaller dimensions which are propagated in parallel at three different (fast, middle and slow) r ates. Because of the reduction in the propagation period for the fast rate part, the approx ima tion accuracy of time-varying system can be improved for a given computer load and a better estimation accuracy is realized . These are verified by computer simulations for the case of a reusable winged vehicle. The triple-rate filter can easily be extended to a multi-rate one.

The first Japanese deepspace probes called Sakigake and Suisei were launched from Uchinoura Launching Site, located at 1,500 km south-west of Tokyo, respectively on January 8 and August 19, 1985. The Institute of Space and Astronautical Science has developed the new four-stage solid propellant boosters called M3S-II for this purpose and constructed a gigantic antenna - 64 m in diameter - in Usuda, located at 150 km north-west of Tokyo. These probes successfully encounted Halley’s comet in March, 1986. In this paper, the guidance and navigation problems, namely the guidance of the last stage rocket in the direct ascent scheme, the midcourse maneuvers and the tracking and navigation of the probes throughout the mission, will be discussed.

We aim to develop the space robot with a manipulator which is operated to catch and handle a target, in zero gravity environment. In this case, the behavior of the robot main body caused by the reaction force exerted by the manipulator motion has to be taken into consideration, in order to control the manipulator correctly. To solve this problem, we have constructed the ground simulation system combining numerical simulation and servo mechanisms. On this system, dynamics of the space robot and the target is solved based on the momentum conservation law, and the relative motion between them is realized. Using this simulation system, we can develop space robots efficiently.