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Combining the age-male-albumin-bilirubin-platelets score and shear wave elastography stratifies carcinogenic risk in hepatitis C patients after viral clearance

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World Journal of Clinical Cases 2023年第22期11卷 5204-5214页

作者： rion Masaoka Yoshinori Gyotoku Ryosaku Shirahashi Toshikuni Suda Masaya Tamano Department of Gastroenterology Dokkyo Medical University Saitama Medical CenterKoshigaya 343-8555SaitamaJapan

BACKGROUND The treatment of hepatitis C with direct-acting antiviral agents(DAAs)produces a high rate of sustained virological response(SVR)with fewer adverse events than interferon(IFN)therapy with a similar effect in inhibiting carcinogenesis as IFN therapy.The age-male-albumin-bilirubin-platelets(aMAP)score is useful for stratifying the risk of hepatocellular carcinoma in chronic hepatitis patients,and the velocity of shear waves(Vs)measured by shear wave elastography has also been shown to be useful for diagnosing the level of fibrotic progression in hepatitis C and predicting carcinogenic risk.Combining these two may improve the prediction of carcinogenic risk.AIM To determine whether combining the aMAP score with Vs improves carcinogenic risk stratification in medium-to-high-risk hepatitis C patients.METHODS This retrospective,observational study involved hepatitis C patients treated with DAAs who achieved SVR.Vs was measured before treatment(baseline),at the end of treatment(EOT),and 12 wk(follow-up 12)and 24 wk(follow-up 24)after treatment.The patients were followed for at least six months after EOT to determine whether cancer developed.Multiple regression analysis was used to identify factors contributing to hepatic carcinogenesis.The diagnostic performances of clinical parameters for predicting the presence of hepatocellular carcinoma were evaluated using receiver-operating characteristic(ROC)curve analyses.RESULTS A total of 279 patients(mean age 65.9 years,118 males,161 females)were included in the analysis.Multiple regression analysis was performed with carcinogenesis as the target variable and alanine aminotransferase,platelets,α-fetoprotein,Vs,and the Fib-4 index as explanatory variables;only Vs was found to be significant(P=0.0296).The cut-off value for Vs for liver carcinogenesis calculated using the ROC curve was 1.53 m/s.Carcinoma developed in 2.0%(3/151)of those with Vs<1.53 m/s and in 10.5%(9/86)of those with Vs≥1.53 m/s.CONCLUSION In hepatitis C patients after SVR,combining the aMAP score an

关键词： Hepatitis C Hepatocellular carcinoma Direct-acting antiviral therapy Shear wave elastography Sustained virological response Age-male-albumin-bilirubin-platelets score

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中华穿山甲

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博物 2018年第6期 88-89页

作者：王辰 rion 梁嘉宜

这是一座假想的公寓。公寓里的住客，都是我国的野生动物，有特有种类，也有珍稀濒危的种类，他们共同的特点是：荫荫哒。每种动物一个房间，按照它们原本的生境来装修布置。我们一起来参观这座萌之屋吧!

关键词：穿山甲中华野生动物珍稀濒危公寓种类

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川金丝猴

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博物 2018年第5期 86-87页

作者：王辰 rion 梁嘉宜

这是一座假想的公寓。公寓里的住客，都是我国的野生动物，有特有种类，也有珍稀濒危的种类，它们共同的特点是：萌萌哒。每种动物拥有一个房间，按照它们原本的生境来装修布置。我们一起来参观这座荫之屋吧!

关键词：川金丝猴野生动物珍稀濒危公寓种类

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Shear wave elastography in hepatitis C patients before and after antiviral therapy

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World Journal of Hepatology 2017年第1期9卷 64-68页

作者： Toshikuni Suda Osamu Okawa rion Masaoka Yoshinori Gyotoku Naohiko Tokutomi Yasumi Katayama Masaya Tamano Department of Gastroenterology Dokkyo Medical University Koshigaya HospitalSaitama 343-8555Japan

AIM To investigate shear wave(SW) propagation velocity in patients with untreated hepatitis C and patients with sustained virological response(SVR). METHODS A total of 136 hepatitis C patients [85 patients who had not received antiviral therapy(na?ve group) and 51 patients who had received antiviral therapy and subsequently achieved SVR of at least 24 wk(SVR group)] and 58 healthy volunteers and outpatients without liver disease(control group) underwent evaluation of liver stiffness by SW elastography(SWE). Various parameters were evaluated in the chronic hepatitis C patients at the time of SWE.RESULTS SW propagation velocity(Vs) was 1.23 ± 0.14 m/s in the control group, 1.56 ± 0.32 m/s in the SVR group, and 1.69 ± 0.31 m/s in the na?ve group. Significant differences were seen between the control group and the SVR group(P = 0.0000) and between the SVR group and the na?ve group(P = 0.01417). All four fibrosis markers were higher in the na?ve group than in the SVR group. In the na?ve group, Vs was positively correlated with alanine aminotransferase(ALT)(r = 0.5372), α feto protein(AFP)(r = 0.4389), type Ⅳ collagen(r = 0.5883), procollagen Ⅲ peptide(P-Ⅲ-P)(r = 0.4140), hyaluronic acid(r = 0.4551), and Mac-2 binding protein glycosylation isomer(M2BPGi)(r = 0.6092) and negatively correlated with albumin(r =-0.4289), platelets(r =-0.5372), and prothrombinactivity(r =-0.5235). On multiple regression analysis, Vs was the most strongly correlated with ALT(standard partial regression std β = 0.4039, P = 0.00000). In the SVR group, Vs was positively correlated with AFP(r = 0.6977), type IV collagen(r = 0.5228), P-Ⅲ-P(r = 0.5812), hyaluronic acid(r = 0.5189), and M2BPGi(r = 0.6251) and negatively correlated with albumin(r =-0.4283), platelets(r =-0.4842), and prothrombin activity(r =-0.4771). On multiple regression analysis, Vs was strongly correlated with AFP(standard partial regression std β = 0.5953, P = 0.00000) and M2BPGi(standard partial regression std β = 0.2969, P = 0.03363).CONCLUSION In hepatitis C patients, liver

关键词： Hepatocarcinogenesis 持续 virological 反应抗病毒的治疗砍波浪 elastography 丙肝

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A Study of Discrete-Time Optimum Current Controller for the Virtual Synchronous Generator under Constraints

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Smart Grid and Renewable Energy 2020年第1期11卷 1-20页

作者： Atushi Umemura rion Takahashi Junji Tamura Department of Electrical and Eslectronic Engineering Kitami Institute of Technology Kitami Japan

In recent years, power generation using renewable energy sources has been increasing as a solution to the global warning problem. Wind power generation can generate electricity day and night, and it is relatively more efficient among the renewable energy sources. The penetration level of variable-speed wind turbines continues to increase. The interconnected wind turbines, however, have no inertia and no synchronous power. Such devices can have a serious impact on the transient stability of the power grid system. One solution to stabilize such grid with renewable energy sources is to provide emulated inertia and synchronizing power. We have proposed an optimal design method of current control for virtual synchronous generators. This paper proposes an optimal control method that can follow the virtual generator model under constrains. As a result, it is shown that the proposed system can suppress the peak of the output of semiconductor device under instantaneous output voltage drop.

关键词： Wind Energy Generation Virtual Synchronous Generator Electric Current Control Optimal Control Discreate-Time Model Following Control Multi-Objective Genetic Algorithm

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Stability Enhancement of Small-Scale Power Grid with Renewable Power Sources by Variable Speed Diesel Power Plant

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Journal of Power and Energy Engineering 2020年第3期8卷 1-17页

作者： rion Takahashi Atsushi Umemura Junji Tamura Department of Earth Energy and Environmental Engineering Kitami Institute of Technology Kitami Japan

This paper proposes a power control method to improve a stability of a small-scale power grid with renewable energy sources. In an isolated small- scale power grid such as an island, diesel power plant is main power source which has an environmental burden and expensive running cost due to high priced fossil fuel. Thus, expanding installation of the renewable energy sources such as a wind power is strongly desirable. Such fluctuating energy sources, however, harm power quality of the small-scale power grid, and in addition, conventional power plant in the small-scale power grid cannot, in general, stabilize the grid system with such fluctuating power sources. In this study, Variable Speed Doubly-Fed Induction Generator (VS-DFIG) is proposed to be in-stalled at a diesel power plant instead of a conventional Fixed Speed Synchronous Generator (FS-SG), because quick control of a power balance in the small-scale power grid can be achieved by using the inertial energy of VS-DFIG. In addition, utilization of a Battery Energy Storage System (BESS) is also considered to assist cooperatively the VS-DFIG control. As a result of the simulation analysis by using the proposed method, it is verified that frequency fluctuations due to renewable energy source can be effectively reduced by quick power control of the VS-DFIG compared to the conventional FS-SG, and further control ability can be obtained by utilizing BESS. Moreover, the transient stability of a small-scale power grid during a grid fault can also be enhanced.

关键词： Small-Scale Power Grid Variable Speed Doubly-Fed Induction Generator (VS-DFIG) Diesel Power Plant Wind Power Battery Energy Storage System (BESS)

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The Novel Current Control for Virtual Synchronous Generator

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Journal of Power and Energy Engineering 2020年第2期8卷 78-89页

作者： Atsushi Umemura rion Takahashi Junji Tamura Department of Electrical and Electronic Engineering Kitami Institute of Technology Kitami Japan

In recent years, power generation using renewable energy sources has been developed as a solution to the global warming problem. Among these power generation methods, wind power generation is increasing. However, as the penetration level of wind power generation increases, the low inertia and lack of synchronous power characteristics of the penetrated power system can have a significant impact on the transient stability of the grid. The virtual synchronous generator provides the ability of virtual inertia and synchronous power to interconnected inverters. The interconnected inverter with the virtual synchronous generator ability uses, in general, PI control based current controller. This paper proposes a new current-control method and compares it with conventional methods. The proposed current control is a method that follows virtual synchronous generator model that changes every moment by solving the discrete-time linear quadratic optimal control problem for each sampling time interval. The new method follows the conventional method, and therefore the reactive power fluctuation can be suppressed and the interconnected inverter will be downsized.

关键词： Wind Energy Generation State Feedback Electric Current Control Linearization Techniques Discrete Time Model Following Control Virtual Synchronous Generator

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Enhancement of DC-Link Protection of PMSG Based Wind Turbine under Network Disturbance by Using New Buck Controller System

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Journal of Mechanics Engineering and Automation 2017年第4期7卷 171-179页

作者： Linda Sartika Atsushi Umemura rion Takahashi Junji Tamura Department of Electrical and Electronic Engineering Kitami Institute of Technology (KIT) Hokkaido 090-8507 Japan

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Stabilization of Wind Farm by Using PMSG Based Wind Generator Taking Grid Codes into Consideration

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Journal of Power and Energy Engineering 2018年第11期6卷 40-52页

作者： Md. Rifat Hazari Mohammad Abdul Mannan Atsushi Umemura rion Takahashi Junji Tamura Department of Electrical and Electronic Engineering Kitami Institute of Technology (KIT) 165 Koen-cho Kitami Hokkaido 090-8507 Japan Department of Electrical and Electronic Engineering American International University-Bangladesh (AIUB) 408/1 Kuratoli Khilkhet Dhaka Bangladesh

This paper presents a new operational strategy for a large-scale wind farm (WF) which is composed of both fixed speed wind turbines with squirrel cage induction generators (FSWT-SCIGs) and variable speed wind turbines with permanent magnet synchronous generators (VSWT-PMSGs). FSWT-SCIGs suffer greatly from meeting the requirements of fault ride through (FRT), because they are largely dependent on reactive power. Integration of flexible ac transmission system (FACTS) devices is a solution to overcome that problem, though it definitely increases the overall cost. Therefore, in this paper, a new method is proposed to stabilize FSWT-SCIGs by using VSWT-PMSGs in a WF. This is achieved by injecting the reactive power to the grid during fault condition by controlling the grid side converter (GSC) of PMSG. The conventional proportional-integral (PI)-based cascaded controller is usually used for GSC which can inject small amount of reactive power during fault period. Thus, it cannot stabilize larger rating of SCIG. In this paper, a suitable fuzzy logic controller (FLC) is proposed in the cascaded controller of GSC of PMSG in order to increase reactive power injection and thus improve the FRT capability of WF during voltage dip situation due to severe network fault. To evaluate the proposed controller performance, simulation analyses are performed on a modified IEEE nine-bus system. Simulation results clearly show that the proposed method can be a cost-effective solution which can effectively stabilize the larger rating of SCIG compared to conventional PI based control strategy.

关键词： Wind Turbine Generator Fuzzy Logic Controller Power System Stability Power Converter PI Controller

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Frequency Control of Power System with Solar and Wind Power Stations by Using Frequency Band Control and Deadband Control of HVDC Interconnection Line

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Journal of Power and Energy Engineering 2018年第9期6卷 48-63页

作者： Kimiko Tada Takamasa Sato Atsushi Umemura rion Takahashi Junji Tamura Yoshiharu Matsumura Tsukasa Taguchi Akira Yamada Department of Electrical and Electronic Engineering Kitami Institute of Technology (KIT) Kitami Japan Hokkaido Electric Power Co. Inc. Sapporo Japan

In recent years, environmental problems are becoming serious and renewable energy has attracted attention as their solutions. However, the electricity generation using the renewable energy has a demerit that the output becomes unstable because of intermittent characteristics, such as variations of wind speed or solar radiation intensity. Frequency fluctuations due to the installation of large scale wind farm (WF) and photovoltaics (PV) into the power system is a major concern. In order to solve the problem, this paper proposes two control methods using High Voltage Direct Current (HVDC) interconnection line to suppress the frequency fluctuations due to large scale of WF and PV. Comparative analysis between these two control methods is presented in this paper. One proposed method is a frequency control using a notch filter, and the other is using a deadband. Validity of the proposed methods is verified through simulation analyses, which is performed on a multi-machine power system model.

关键词： High Voltage Direct Current (HVDC) System Frequency Control PV Power Generation Wind Power Generation Notch Filter Deadband

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