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Stability analysis of a noise control system in a duct by using delay differential equation

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Acta Mechanica Sinica 2009年第1期25卷 131-137页

作者： masakazu Haraguchi MOE Key Laboratory of Structure Mechanics and Control for Aircraft Nanjing University of Aeronautics and Astronautics

The paper deals with the criteria for the closed- loop stability of a noise control system in a duct. To study the stability of the system, the model of delay differential equation is derived from the propagation of acoustic wave governed by a partial differential equation of hyperbolic type. Then, a simple feedback controller is designed, and its closed- loop stability is analyzed on the basis of the derived model of delay differential equation. The obtained criteria reveal the influence of the controller gain and the positions of a sensor and an actuator on the closed-loop stability. Finally, numerical simulations are presented to support the theoretical results.

关键词： Stability analysis Delay differential equation Closed-loop stability Noise control Acoustic system

A new reduction-based LQ control for dynamic systems with a slowly time-varying delay

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Acta Mechanica Sinica 2009年第4期25卷 529-537页

作者： masakazu Haraguchi MOE Key Lab of Structure Mechanics and Control for Aircraft Nanjing University of Aeronautics and Astronautics

Time delays in the feedback control often dete- riorate the control performance or even cause the instability of a dynamic system. This paper presents a control strategy for the dynamic system with a constant or a slowly time-varying input delay based on a transformation, which sire-plifies the time-delay system the relation is discussed for into a delay-free one. Firstly, two existing reduction-based linear quadratic controls. One is continuous and the other is discrete. By extending the relation, a new reduction-based control is then developed with a numerical algorithm presented for practical control implementation. The controller suggested by the proposed method has such a promising property that it can be used for the cases of different values of an input time delay without redesign of controller. This property provides the potential for stabilizing the dynamic system with a time-varying input delay. Consequently, the application of the proposed method to the dynamic system with a slowly time-varying delay is discussed. Finally, numerical simulations are given to show the efficacy and the applicability of the method.

关键词： Time delay Time-varying delay State transformation System reduction Linear quadratic control

Estimating effects from trapped magnetic fluxes in superconducting magnetic levitation measurement

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仪器仪表学报 2008年第3期29卷 449-452页

作者： masakazu Nakanishi Metrology Institute of Japan National Institute of Advanced Industrial Science and Technology 1-1-1 Umezono Tsukuba-shi Ibaraki 305-8563 Japan

Superconducting magnetic levitation measurement is one of the most promising approaches to define mass standard based on the fundamental physical constants. However, the present system has unknown factors causing error larger than 50 ppm. We examined the effects of magnetic fluxes trapped in the superconducting coil and the superconducting floating body. When fluxes were trapped in either coil or floating body, their effects were able to be cancelled by reversing polarities of current and magnetic field, as had been believed. However, fluxes trapped in both coil and body induced an attractive force between them and caused error. In order to reduce the fluxes, the coil and the floating body should be cooled in low magnetic field in magnetic and electromagnetic shields.

关键词：截留磁通量超导电磁飘浮测量基本物理常量

Verification of Subseasonal-to-Seasonal Forecasts for Major Stratospheric Sudden Warmings in Northern Winter from 1998/99 to 2012/13

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Advances in Atmospheric Sciences 2020年第3期37卷 250-258页

作者： masakazu TAGUCHI Department of Earth Science Aichi University of Education

This study reports verification results of hindcast data of four systems in the subseasonal-to-seasonal(S2S)prediction project for major stratospheric sudden warmings(MSSWs)in northern winter from 1998/99 to 2012/*** report deals with average features across all MSSWs,and possible differences between two MSSW types(vortex displacement and split types).Results for the average features show that stratospheric forecast verifications,when further averaged among the four systems,are judged to be successful for lead times around 10 d or *** systems are skillful for lead times around 5 d,whereas the results vary among the systems for longer lead times.A comparison between the MSSW types overall suggests larger forecast errors or lower skill for MSSWs of the vortex split type,although the differences do not have strong statistical significance for almost all *** limitation is likely to at least partly reflect the small sample size of the MSSWs available.

关键词： major stratospheric sudden warmings forecast verification subseasonal-to-seasonal prediction project vortex displacement and split warmings

Ulcerative colitis-associated colorectal cancer

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World Journal of Gastroenterology 2014年第44期20卷 16389-16397页

作者： masakazu Yashiro Department of Surgical Oncology Osaka City University Graduate School of Medicine Oncology Institute of Geriatrics and Medical Science Osaka City University Graduate School of Medicine

The association between ulcerative colitis(UC) and colorectal cancer(CRC) has been acknowledged. One of the most serious and life threatening consequences of UC is the development of CRC(UC-CRC). UC-CRC patients are younger, more frequently have multiple cancerous lesions, and histologically show mucinous or signet ring cell carcinomas. The risk of CRC begins to increase 8 or 10 years after the diagnosis of UC. Risk factors for CRC with UC patients include young age at diagnosis, longer duration, greater anatomical extent of colonic involvement, the degree of inflammation, family history of CRC, and presence of primary sclerosing cholangitis. CRC on the ground of UC develop from non-dysplastic mucosa to indefinite dysplasia, lowgrade dysplasia, high-grade dysplasia and finally to invasive adenocarcinoma. Colonoscopy surveillance programs are recommended to reduce the risk of CRC and mortality in UC. Genetic alterations might play a role in the development of UC-CRC. 5-aminosalicylates might represent a favorable therapeutic option for chemoprevention of CRC.

关键词： Ulcerative colitis-associated colorectal cancer Risk factor Dysplasia Surveillance colonoscopy Chemoprevention

Epigenetic memory of drug exposure history controls neural stem cell quiescence in the adult brain

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维普期刊数据库

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Neural Regeneration Research 2024年第4期19卷 711-712页

作者： masakazu Iwamoto Taito Matsuda Department of Stem Cell Biology and Medicine Graduate School of Medical SciencesKyushu UniversityFukuokaJapan

Neural stem cells(NSCs)are the source of all neurons and glial cells(astrocytes and oligodendrocytes)in the central nervous *** adult mammalian brain retains NSCs in the subgranular zone of the dentate gyrus in the hippocampus and ventricular subventricular zone lining the lateral ventricle(Olpe and Jessberger,2022).Adult NSCs in rodents are preserved throughout life and continuously produce new neurons that integrate into the pre-existing neuronal network.

关键词： neural integrate continuously

Molecular-targeted therapy toward precision medicine for gastrointestinal caner:Current progress and challenges

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World Journal of Gastrointestinal Oncology 2021年第5期13卷 366-390页

作者： Tasuku Matsuoka masakazu Yashiro Department of Surgical Oncology Osaka City University Graduate School of MedicineOsaka 545-8585Japan

Gastrointestinal(GI)cancer remains the deadliest cancer in the *** current standard treatment for GI cancer focuses on 5-fluorouracil-based chemotherapeutic regimens and surgery,and molecular-targeted therapy is expected to be a more effective and less toxic therapeutic strategy for GI *** is wellestablished evidence for the use of epidermal growth factor receptor-targeted and vascular endothelial growth factor-targeted antibodies,which should routinely be incorporated into treatment strategies for GI *** potential therapeutic targets involve the PI3K/AKT pathway,tumor growth factor-βpathway,mesenchymal-epithelial transition pathway,WNT pathway,poly(ADP-ribose)polymerase,and immune *** clinical trials assessing the agents of targeted therapy are underway and have presented promising and thoughtprovoking *** the development of molecular biology techniques,we can identify more targetable molecular alterations in larger patient populations with GI *** these molecules will allow us to reach the goal of precision medicine and improve the outcomes of patients with GI cancer.

关键词： Gastrointestinal cancer Esophageal cancer Gastric cancer Colorectal cancer Targeted therapy Precision medicine

Fibroblast growth factor receptor signaling as therapeutic targets in gastric cancer

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World Journal of Gastroenterology 2016年第8期22卷 2415-2423页

作者： masakazu Yashiro Tasuku Matsuoka Department of Surgical Oncology Osaka City University Graduate School of Medicine Oncology Institute of Geriatrics and Medical Science Osaka City University Graduate School of Medicine

Fibroblast growth factor receptors(FGFRs) regulate a variety of cellular functions, from embryogenesis to adult tissue homeostasis. FGFR signaling also plays significant roles in the proliferation, invasion, and survival of several types of tumor cells. FGFR-induced alterations, including gene amplification, chromosomal translocation, and mutations, have been shown to be associated with the tumor initiation and progression of gastric cancer, especially in diffuse-type cancers. Therefore, the FGFR signaling pathway might be one of the therapeutic targets in gastric cancer. This review aims to provide an overview of the role of FGFR signaling in tumorigenesis, tumor progression, proliferation, and chemoresistance. We also discuss the accumulating evidence that demonstrates the effectiveness of using clinical therapeutic agents to inhibit FGFR signaling for the treatment of gastric cancer.

关键词： Fibroblast growth factor receptor Gastric cancer Signaling pathway Targeted therapy

Rho/ROCK signaling in motility and metastasis of gastric cancer

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World Journal of Gastroenterology 2014年第38期20卷 13756-13766页

作者： Tasuku Matsuoka masakazu Yashiro Department of Surgical Oncology Osaka City University Graduate School of Medicine

Gastric cancer is one of the most frequent and lethal malignancies worldwide because of high frequency of metastasis. Tumor cell motility and invasion play fundamental roles in cancer metastasis. Recent studies have revealed that the Rho/Rho-associated protein kinases(ROCK) pathway plays a critical role in the regulation of cancer cell motility and invasion. In addition,the Rho/ROCK pathway plays important roles in invasion and metastasis on the basis of its predominant function of cell cytoskeletal regulation in gastric cancer. According to the current understanding of tumor motility,there are two modes of tumor cell movement:mesenchymal and amoeboid. In addition,cancer cell movement can be interchangeable between the mesenchymal and amoeboid movements under certain conditions. Control of cell motility through the actin cytoskeleton creates the potential for regulating tumor cell metastasis. In this review we discuss Rho GTPases and ROCK signaling and describe the mechanisms of Rho/ROCK activity with regard to motility and metastasis in gastric *** addition,we provide an insight of the therapeutic potential of targeting the Rho/ROCK pathway.

关键词： RhoGTPases Rho-associated protein kinases Gastric cancer Motility Metastasis