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259 results on '"Sakamoto, Kiyoshi"'

12. Chattering reduction of disturbance observer based sliding mode control

Author

Kawamura, Atsuo, Itoh, Hiroshi, and Sakamoto, Kiyoshi

Subjects
Control theory -- Research, Liapunov functions -- Usage, Business, Computers, Electronics, Electronics and electrical industries
Abstract

The reduction of the chattering of sliding mode control is achieved by combination of disturbance observer and feed forward control. Using the Lyapunov stability theorem, design methodology of disturbance observer based sliding mode control is proposed, and the result is applied to a two axis SCARA robot. Through simulations and experiments, it is verified that the proposed control has advantage in the less chattering with the robustness of sliding mode control. Also, the calculation of the reference angles is proposed to enhance the robustness of the propose control.

Published
1994

14. Increased expression of membrane-associated phospholipase A2 shows malignant potential of human breast cancer cells

Author

Yamashita, Shin-ichi, Yamashita, Jun-ichi, Sakamoto, Kiyoshi, Inada, Kazuo, Nakashima, Yasunari, Murata, Kazuya, Saishoji, Tetsushi, Nomura, Koichi, and Ogawa, Michio

Subjects
Breast cancer -- Prognosis, Phospholipases -- Measurement, Health
Abstract

Background. Recently, the authors reported that membrane-associated phospholipase [A.sub.2] (M-[PLA.sub.2]) was one of the acute phase reactants and increased in serum of patients with various malignant tumors. Methods. M-[PLA.sub.2] concentrations in tissue specimens from 78 breast cancers, 16 benign breast tumors, and 10 normal breast tissues were determined by a specific radioimmunoassay recently developed. Immunohistochemical staining was performed on all specimens by the avidin-biotin-peroxidase method. Results. Tissue levels of M-[PLA.sub.2] concentration were significantly higher in breast cancer than in benign breast tumor or normal breast tissue (P < 0.01). Correlation analyses between the tissue concentration of M-[PLA.sub.2] and clinicopathologic factors showed that tissue M-[PLA.sub.2] levels were significantly higher in patients with skin or muscle invasion, vessel involvement, and distant metastasis than in those without. In addition, this enzyme concentration was significantly greater in scirrhous carcinoma than in papillotubular or solid-tubular carcinoma. No association was found between M-[PLA.sub.2] concentration and steroid hormone receptor status. Immunohistochemically, M-[PLA.sub.2] was preferentially stained in the invading zone of breast cancer tissues, especially in scirrhous carcinoma. Patients with breast cancer with low levels of M-[PLA.sub.2] showed significantly longer overall survival and disease-free survival compared with those with high levels of this enzyme at the cutoff point of 50 ng/100 mg protein. The combination of estrogen receptor status with M-[PLA.sub.] concentration could be a powerful prognostic factor in predicting such survival rates. Conclusions. M-[PLA.sub.2] is closely related to the malignant potential of breast cancers, and the M-[PLA.sub.2] contents in breast cancer tissues could be a new valuable prognostic factor, other than the hormone receptor, in delineating the status of human breast cancer. Cancer 1993; 71:3058-64.

Published
1993

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