Jak3 is a tyrosine kinase mediating cytokine receptor signaling through the association with the common gamma chain of the cytokine receptors such as IL-2, IL-4, IL-7, IL-9, and IL-15. Unlike other members of the Jak family, the expression of Jak3 is highly restricted in hematopoietic cells. To elucidate in vivo function of Jak3, Jak3-deficient mice were generated by homologous recombination. Mice homozygous for Jak3 null mutation showed severe defects, specifically in lymphoid cells. B cell precursors in bone marrow, thymocytes, and both T and B cells in the spleen drastically decreased, although these defects were significantly recovered as aging occurred. Peripheral lymph nodes, NK cells, dendritic epidermal T cells, and intestinal intraepithelial gamma delta T cells were absent. Normal number of hematopoietic stem cells in bone marrow from Jak3-deficient mice and the similar capability to generate myeloid and erythroid colonies as wild-type mice indicated specific defects in lymphoid stem cells. Furthermore, the abnormal architecture of lymphoid organs suggested the involvement of Jak3 in the function of epithelial cells. T cells developed in the mutant mice did not respond to either IL-2, IL-4, or IL-7. These findings establish the crucial role of Jak3 in the development of lymphoid cells.

Previous researchers of citation analysis often analyze patent data of a single authority because of the availability of the data and the simplicity of analysis. Patent analysis, on the other hand, is used not only for filing and litigation, but also for technology trend analysis. However, global technology trends cannot be understood only with the analysis of patent data issued by a single authority. In this paper, we propose the use of patents from multiple authorities and discuss the effect of bundling patent family information. We investigate the effect of patent families with cases from automobile drivetrain technology. Based on the results, we conclude that the use of multiple authorities' patent data bundled with the patent family information can significantly improve the coverage and practicability of patent citation analysis.

A torque converter lock-up clutch slip control system, which is designed to improve fuel economy, must be able to precisely regulate slip speed. Also the system must have a high level of robustness for coping with changes in the operating conditions and any deterioration in the automatic transmission fluid and the clutch. Moreover, to reduce the design time, the design process must be as simple as possible. In this paper, we first propose a loop shaping that aims to optimize complementary sensitivity function of the control system, while satisfying the abovementioned requirements of performance and robustness. Next, a method for simplifying the design process is proposed, that is, a model and a controller are expressed by interpolation. A controller set, which has a relationship of duality to the interpolation parameters of the model, is created in advance so that the construction of a new control system can be realized by identifying the characteristic parameters only. From application to the actual design process for a vehicle, we verified that the design time was reduced to less than 1∕3 of that required for the conventional method. This new method has already been adopted for the design and fitting of new products.

This paper describes the development ofa robust feedback controller for the torqueconverter-clutch slip control system mounted in the Toyota A245E automatic trans-axle. H"t~ntro1 theory was applied as a systematic design method in order to ensure robust stability against large variation in characteristics under vehicle operating conditions and variation in liiction characteristics ofthe clutch induced by aging deterioration. This theory enables a detailed design in the frequency domain. As aresult, the control system achieves high levels ofresponse and reliability, which contribute to a large-scale reduction ofhel consumption.

Lowering the belt clamping force from the current setting value is effective for increasing the transfer efficiency in a metal V-belt type CVT (Continuously Variable Transmission). However, setting the clamping force too low will cause macro slip (large belt slip). Setting of the clamping force to the proper level therefore requires a detailed understanding of the friction characteristics between the belt and the pulley (belt friction characteristics) and requires that the macro slip threshold be clearly defined. In this paper, we propose a friction expression model for a metal V-belt type CVT and use this model to clarify the state of power transmission in the vicinity of the macro slip limit.