Finger-Shaped GelForce: Sensor for Measuring Surface Traction Fields for Robotic Hand.

It is believed that the use of haptic sensors to measure the magnitude, direction, and distribution of a force will enable a robotic hand to perform dexterous operations. Therefore, we develop a new type of finger-shaped haptic sensor using GelForce technology. GelForce is a vision-based sensor that can be used to measure the distribution of force vectors, or surface traction fields. The simple structure of the GelForce enables us to develop a compact finger-shaped GelForce for the robotic hand. GelForce that is developed on the basis of an elastic theory can be used to calculate surface traction fields using a conversion equation. However, this conversion equation cannot be analytically solved when the elastic body of the sensor has a complicated shape such as the shape of a finger. Therefore, we propose an observational method and construct a prototype of the finger-shaped GelForce. By using this prototype, we evaluate the basic performance of the finger-shaped GelForce. Then, we conduct a field test by performing grasping operations using a robotic hand. The results of this test show that using the observational method, the finger-shaped GelForce can be successfully used in a robotic hand.

Establishment of feeder-independent cloned caprine trophoblast cell line which expresses placental lactogen and interferon tau.

A feeder-independent cloned trophoblast cell line, HTS-1, was established from a mature placenta of Shiba goat (Capra hircus). During the growth phase, single HTS-1 cells exhibited ruffled membranes or lamellipodia often accompanied by elongated cell shape, indicating highly motile nature of the cells. At or near confluence, HTS-1 cells formed monolayers with few sign of cellular overlapping. Binucleate cells were found at a high frequency especially in the peripheral regions of monolayers. In small colonies and the monolayers, majority of HTS-1 cells assumed polygonally shaped cobble-stone like morphology characteristic to epithelial cells, although considerable variations in cellular morphology were observed despite of repeated cloning. Time-lapse video recordings of HTS-1 cells during culture revealed that not only the small colonies but also the monolayers near or at confluence were remarkably motile, often causing extreme elongation of the cells within them. The extremely plastic nature of HTS-1 cells in vitro is likely to be the reflection of the extraordinary capacity of caprine trophoblast cells to be stretched to extreme thinness in vivo as shown by electron microscopy. HTS-1 cells cultured on matrigel are highly invasive, and express MT1-MMP which, in the mouse, has been known to be expressed at the invasive edge of trophoblast both in vitro and in vivo. HTS-1 cells express placental lactogen (PL) and interferon-tau (IFNtau), as confirmed by immunocytochemistry, Western blotting and RT-PCR analysis. Both PL and IFNtau expression in the cells appeared to be down-regulated by cell-cell contact. In the medium conditioned by HTS-1 cells, the presence of secretory form of PL and IFNtau was confirmed by Western blotting. The HTS-1 cell line will serve as a useful in vitro model for the analysis of the molecular and/or cellular mechanisms underlying synepitheliochorial placentation in bovidae animals.

[Networked robotics: its present status and future prospect].

One of the most promising technologies today is the integration of virtual reality and robotics on a network. This is called network robotics in general and R-cubed (real-time remote robotics) in particular. R-cubed is a Japanese national R&D scheme to realize augmented telexistence (tele-existence) through various kinds of networks including the Internet. Telexistence is a concept named for the technology that enables people to have a real-time sensation of being present at a location other than the place where they actually exist, and to interact with a remote and/or virtual environment. They can thus "telexist" in a real environment that the robot is present or in a virtual environment that a computer has generated. It is also possible to telexist in a mixed environment of real and virtual which can be called augmented telexistence. The concept of telexistence, i.e., virtual existence in a remote or computer-generated environment, has developed into the national R-cubed R&D scheme to create an advanced and comfortable life for the network society of the 21st century. Based on the national R&D scheme of R-Cubed, the Humanoid Robotics Project (HRP) was launched in April 1998. This is an effort to integrate telerobotics, network technology, and virtual reality into networked telexistence, and significant results are expected.

Cell-cell contact down-regulates expression of membrane type metalloproteinase-1 (MT1-MMP) in a mouse mammary gland epithelial cell line.

Membrane type matrix metalloproteinase (MT-MMP), which possesses a C-terminal transmembrane domain, is expressed on the cell membrane (Sato et al., 1994, Nature 370: 61-65). It was suspected, therefore, that the expression of MT-MMPs might be regulated by cell-cell interactions. We examined the patterns of MT1-MMP expression in a mouse mammary gland epithelial cell line, HC11, which is capable of responding to prolactin in vitro. HC11 cells form well-differentiated monolayer of cuboidal epithelium at confluence. During the log growth phase, cells which are well dispersed and seemingly migrating actively, or located at the periphery of small colonies, reacted strongly with an anti-MT1-MMP antibody, whereas no MT1-MMP immunoreactivity was detected in the cells which established cell-cell contact with adjacent cells. At confluence, the HC11 cells lost MT1-MMP immunoreactivity completely. Northern blot analysis revealed that MT1-MMP mRNA is present at a high level in HC11 cells during the log phase of growth. Although MT1-MMP immunoreactivity disappeared by the 1st day confluence was reached, the decline of MT1-MMP mRNA levels started only a few days later. The discrepancy in the timing of decrease of MT1-MMP protein and that of the transcripts suggests the presence of translational control mechanisms for MT1-MMP expression during cell-cell interaction.

Formation of the myelinated nerve fiber layer in the chicken retina.

Oligodendrocytes in the ganglion cell layer, the myelinating cells in the chicken retina, were investigated morphologically and quantitatively. Oligodendroblasts divided in the inner retinal layer around the 14th day of incubation and differentiated into oligodendrocytes. The oligodendrocytes started sheathing an axon in the nerve fiber layer at the 14th day of incubation. The number of myelin lamellae increased rapidly during the first week after chicks had hatched. An immunological reaction of anti-myelin basic protein was observed on the myelin sheaths in the nerve fiber layer and on the oligodendrocytes in the ganglion cell layer. These results suggest that the oligodendrocytes form the myelinated nerve fiber layer of the chicken and that they act independently of the Müller cells during myelination.

Electron microscopic analysis of the effect of progesterone upon the hormone-sensitive solitary cilia and centriolar complexes in the luminal epithelial cells of the uterus of the ovariectomized-adrenalectomized rat.

The time course of the hormonally controlled deciliation cycles of the centriolar complexes in the cells of the luminal epithelium of the uterus of the ovariectomized and adrenalectomized rat was analyzed at ultrastructural levels. The results were expressed quantitatively. The half-life of the solitary cilia after progesterone administration in the cell population was 14.6 hr, longer approximately by 1 hr than that previously reported for the estrogen-induced deciliation of the same cells. The time course of the progesterone-induced loss of solitary cilia strongly suggested that the phenomenon is biphasic. After the initial loss of 50%, the process progressed slowly. Twenty-four hours after the injection of the hormone, 35% of the cilia remained; after 60 hours, 4% were still present. This is in striking contrast to the effect of estrogen, which causes almost complete deciliation within 24 hr after the injection of the hormone. Prolonged exposure of the deciliated luminal epithelial cells to progesterone leads to disarrangement of the diplosome relationship. The phenomenon might be causally correlated with the block of estrogen-induced mitoses by this hormone; this view, however, needs further experimental corroboration.