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Characteristics and predictors of gastric cancer after Helicobacter pylori eradication

World Journal of Gastroenterology 2018年第20期24卷 2163-2172页

作者： Satoki Shichijo Yoshihiro hirata Department of Gastrointestinal Oncology Osaka International Cancer Institute Division of Advanced Genome Medicine The Institute of Medical Science The University of Tokyo

Helicobacter pylori(H. pylori) eradication can reduce gastric cancer. However, gastric cancer still develops after eradication, and cases who received eradication therapy are increasing. In this study, we have reviewed the characteristics and predictors of primary gastric cancer developing after H. pylori eradication. In terms of the characteristics, endoscopic, histologic, and molecular characteristics are reported. Endoscopically, gastric cancer after eradication is often depressedtype and shows a gastritis-like appearance, which sometimes makes the diagnosis difficult. Histologically, most gastric cancer after eradication is intestinal type, and non-neoplastic epithelium, also called epithelium with low-grade atypia, is frequently seen over the tumor, which is presumably the cause of the endoscopic gastritis-like appearance. As for molecular characteristics, some markers, such as Ki67, MUC2, and Wnt5a expression, are lower in cancer from patients in whom H. pylori has been eradicated. In terms of predictors, several Japanese studies have reported that severe endoscopic atrophy at eradication is a risk factor for gastric cancer development. Histologic intestinal metaplasia, especially in the corpus, and long-term use of proton pump inhibitors, are also reported as risk factors for gastric cancer after H. pylori eradication. These studies on the characteristics and predictors of gastric cancer development will become the cornerstone for establishing a novel surveillance program based on the gastric cancer risk stratification specific to H. pylori-eradicated patients.

关键词： gastric cancer eradication characteristic Helicobacter pylori predictor

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Two-degree-of-freedom H-infinity control of combustion in diesel engine using a discrete dynamics model

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Control Theory and Technology 2017年第2期15卷 109-116页

作者： Mitsuo hirata Sota ISHIZUKI Masasyasu SUZUKI Department of Electrical and Electronic Systems Engineering Utsunomiya University 7-1-2 Yoto Utsunomiya Tochigi 321-8585 Japan

This paper proposes an H-infinity combustion control method for diesel engines. The plant model is the discrete dynamics model developed by Yasuda et al., which is implementable on a real engine control unit. We introduce a two-degree-of-freedom control scheme with a feedback controller and a feedforward controller. This scheme achieves both good feedback properties, such as disturbance suppression and robust stability, and a good transient response. The feedforward controller is designed by taking the inverse of the static plant model, and the feedback controller is designed by the H-infinity control method, which reduces the effect of the trubocharger lag. The effectiveness of the proposed method is evaluated in simulations using the nonlinear discrete dynamics model.

关键词： Combustion control diesel engines H-infinity control two-degree-of-freedom control

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Three-Dimensional Lattice Boltzmann Simulation of Two-Phase Flow Containing a Deformable Body with a Viscoelastic Membrane

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Communications in Computational Physics 2011年第5期9卷 1397-1413页

作者： Toshiro Murayama Masato Yoshino Tetsuo hirata Department of Mathematics and System Development Engineering Interdisciplinary Graduate School of Science and TechnologyShinshu University4-17-1 WakasatoNagano-shiNagano 380-8553Japan Satellite Venture Business Laboratory(SVBL) Shinshu University3-15-1 TokidaUeda-shiNagano 386-8567Japan Department of Mechanical Systems Engineering Faculty of EngineeringShinshu University4-17-1 WakasatoNagano-shiNagano 380-8553Japan CREST Japan Science and Technology Agency4-1-8 HonchoKawaguchi-shiSaitama 332-0012Japan

The lattice Boltzmann method(LBM)with an elastic model is applied to the simulation of two-phase flows containing a deformable body with a viscoelastic *** numerical method is based on the LBM for incompressible two-phase fluid flows with the same *** body has an internal fluid covered by a viscoelastic membrane of a finite *** elastic model is introduced to the LBM in order to determine the elastic forces acting on the viscoelastic membrane of the *** the present method,we take account of changes in surface area of the membrane and in total volume of the body as well as shear deformation of the *** using this method,we calculate two problems,the behavior of an initially spherical body under shear flow and the motion of a body with initially spherical or biconcave discoidal shape in square pipe *** deformations of the body(the Taylor shape parameter)for various shear rates are in good agreement with other numerical ***,tank-treading motion,which is a characteristic motion of viscoelastic bodies in shear flows,is simulated by the present method.

关键词： Lattice Boltzmann method(LBM) two-phase flow viscoelastic membrane shear flow tank-treading motion

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Duodenal intussusception secondary to ampullary adenoma: A case report

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World Journal of Clinical Cases 2019年第14期7卷 1857-1864页

作者： Masaaki hirata Yoshiharu Shirakata Kenya Yamanaka Department of Surgery Hyogo Prefectural Amagasaki General Medical CenterAmagasakiHyogo 660-0892Japan

BACKGROUND Because the duodenum is fixed onto the retroperitoneum, duodenal intussusception is usually impossible except in cases of malrotational abnormality. Although cases of duodenal intussusception without malrotational abnormalities have been reported, it is unclear whether they constitute true intussusception or simple mucosal prolapse. CASE SUMMARY A 66-year-old woman presented with whole-body edema and malaise. Blood analysis indicated severe anemia and cholestasis. Endoscopic examination revealed a pedunculate polyp on the second part of the duodenum that migrated distally with mucosal elongation. Computed tomography showed duodenal intussusception. A tumor as the lead point and retroperitoneal structure, including the head of the pancreas and fat, invaginated beyond the duodenojejunal flexure. She was diagnosed with ampullary adenoma caused repeated intussusception that reduced spontaneously and underwent pancreaticoduodenectomy. Laparotomy showed tumor prolapse beyond the duodenojejunal flexure without intussusception. There was no evidence of malrotational abnormality. She was discharged with no complications. CONCLUSION We report true duodenal intussusception without malrotational abnormality. This phenomenon was also associated with mucosal prolapse.

关键词： Duodenal intussusception Mucosal prolapse Ampullary adenoma Case report

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Mathematically modelling and controlling prostate cancer under intermittent hormone therapy

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Asian Journal of Andrology 2012年第2期14卷 270-277页

作者： Yoshito hirata Gouhei Tanaka Nicholas Bruchovsky Kazuyuki Aihara Institute of Industrial Science University of Tokyo Tokyo 153-8505 Japan Vancouver Prostate Centre Vancouver General Hospital Vancouver BC V6H 3Z6 Canada

In this review, we summarize our recently developed mathematical models that predict the effects of intermittent androgen suppression therapy on prostate cancer （PCa）. Although hormone therapy for PCa shows remarkable results at the beginning of treatment, cancer cells frequently acquire the ability to grow without androgens during long-term therapy, resulting in an eventual relapse. To circumvent hormone resistance, intermittent androgen suppression was investigated as an alternative treatment option. However, at the present time, it is not possible to select an optimal schedule of on- and off-treatment cycles for any given patient. In addition, clinical trials have revealed that intermittent androgen suppression is effective for some patients but not for others. To resolve these two problems, we have developed mathematical models for PCa under intermittent androgen suppression. The mathematical models not only explain the mechanisms of intermittent androgen suppression but also provide an optimal treatment schedule for the on- and off-treatment periods.

关键词： diagnosis intermittent androgen suppression mathematical models personalized treatment schedule prognosis prostate cancer

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Quantitative evaluation of die casting surface defect severity by analyzing surface height

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China Foundry 2017年第5期14卷 339-345页

作者： Yan Xu Naoya hirata Koichi Anzai Department of Metallurgy Graduate School of EngineeringTohoku UniversitySendai 980-85 79Japan

It is necessary in factories to assess the severity of the surface defects of castings, as a slight surface defect will be taken as qualified when it brings no bad effect or it can be removed by the subsequent processing. In practical production, professional technicians visually inspect the surface defect severity according to their individual experience. Therefore, it is difficult for them to maintain the same standard and accuracy in the subjective, tedious and labor-intensive work. Recently, image processing techniques based on optical images have been applied to achieve better accuracy and high efficiency. Unfortunately, optical images cannot directly quantify surface depth, which works as a crucial factor in the practical assessment of surface defect severity. The surface roughness evaluation algorithm, which takes into account of both area and depth information of the assessed surface, was applied to directly characterize surface defect severity based on surface asperity rather than optical image. The results using standard casting pieces show that surface defect severity has no apparent dependence on surface roughness. However, the subsequent results show that the root-mean-squared-deviation(RMSD) of surface gradient of flow line defects positively correlates with the increase of defect severity. The other types of defect do not present such tendency. Thus, practical workpieces with flow line defects on the surface were used to verify the universality of this tendency. The results show that surface roughness of an unqualified workpiece is larger than that of a qualified workpiece after surface slope adjustment, but presents no obvious coincidence before the adjustment. In contrast, the RMSD of an unqualified workpiece, no matter before or after the adjustment, is larger than that of a qualified one.

关键词： die casting surface defect surface roughness

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Development of the Driving Simulation System MOVIC-T4 and Its Validation Using Field Driving Data

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Tsinghua Science and Technology 2007年第2期12卷 141-150页

作者： Terumitsu hirata Tetsuo Yai Tsuyoshi Takagawa Institute for Transport Policy Studies 3-18-19 Toranomon Minato-ku Tokyo 105-0001 Japan Department of Built Environment Tokyo Institute of Technology 4259 Nagatsuta-cho Midori-ku Yokohama 226-8502 Japan Trion Corporation 1-35-17-209 Akatsutsumi Setagaya-ku Tokyo 156-0044 Japan

Underground urban expressways are a possibility for solving many existing transportation-related problems, such as traffic congestion in high density areas and the division of neighborhoods due to elevated roadways. However, they may also pose high risks regarding traffic safety. Therefore, it is important for a pre-analysis of traffic safety to be made. This paper describes recent efforts to develop a driving simulation system, MOVIC-T4, for traffic safety analysis of underground urban expressways. In order to develop a small portable simulator, a small-sized motion-base with two-degrees-of-freedom is used to duplicate acceleration cueing together with a head-mounted-display （HMD） for the visual system. An overview of this system is given and the reliability of driving data obtained from the experiments using MOVIC-T4 is discussed through a validation study using field driving data. The results of validation indicate that the perceived speed distance headway, and physiological data in the simulator show the almost same trend as that in the real world, but larger decelerations tend to be produced in the simulator.

关键词： driving simulation system motion-base head-mounted-display validation underground urban expressway

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Lattice Boltzmann Simulation of Nucleate Pool Boiling in Saturated Liquid

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Communications in Computational Physics 2011年第5期9卷 1347-1361页

作者： Yoshito Tanaka Masato Yoshino Tetsuo hirata Department of Mathematics and System Development Engineering Interdisciplinary Graduate School of Science and TechnologyShinshu University4-17-1WakasatoNagano-shiNagano 380-8553Japan Department of Mechanical Systems Engineering Faculty of EngineeringShinshu UniversityNagano-shiNagano 380-8553Japan CREST Japan Science and Technology Agency4-1-8HonchoKawaguchi-shiSaitama 332-0012Japan

A thermal lattice Boltzmann method(LBM)for two-phase fluid flows in nucleate pool boiling process is *** the present method,a new function for heat transfer is introduced to the isothermal LBM for two-phase immiscible fluids with large density *** calculated temperature is substituted into the pressure tensor,which is used for the calculation of an order parameter representing two phases so that bubbles can be formed by nucleate *** using this method,twodimensional simulations of nucleate pool boiling by a heat source on a solid wall are carried out with the boundary condition for a constant heat *** flow characteristics and temperature distribution in the nucleate pool boiling process are *** is seen that a bubble nucleation is formed at first and then the bubble grows and leaves the wall,finally going up with deformation by the buoyant *** addition,the effects of the gravity and the surface wettability on the bubble diameter at departure are numerically *** calculated results are in qualitative agreement with other theoretical predictions with available experimental data.

关键词： Lattice Boltzmann method(LBM) two-phase fluid flows heat transfer nucleate pool boiling wettability

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Initial management for acute lower gastrointestinal bleeding

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World Journal of Gastroenterology 2019年第1期25卷 69-84页

作者： Tomonori Aoki Yoshihiro hirata Atsuo Yamada Kazuhiko Koike Department of Gastroenterology Graduate School of Medicine the University of Tokyo Division of Advanced Genome Medicine the Institute of Medical Sciencethe University of Tokyo

Acute lower gastrointestinal bleeding(LGIB) is a common indication for hospital admission. Patients with LGIB often experience persistent or recurrent bleeding and require blood transfusions and interventions, such as colonoscopic,radiological, and surgical treatments. Appropriate decision-making is needed to initially manage acute LGIB, including emergency hospitalization, timing of colonoscopy, and medication use. In this literature review, we summarize the evidence for initial management of acute LGIB. Assessing various clinical factors,including comorbidities, medication use, presenting symptoms, vital signs, and laboratory data is useful for risk stratification of severe LGIB, and for discriminating upper gastrointestinal bleeding. Early timing of colonoscopy had the possibility of improving identification of the bleeding source, and the rate of endoscopic intervention, compared with elective colonoscopy. Contrast-enhanced computed tomography before colonoscopy may help identify stigmata of recent hemorrhage on colonoscopy, particularly in patients who can be examined immediately after the last hematochezia. How to deal with nonsteroidal antiinflammatory drugs(NSAIDs) and antithrombotic agents after hemostasis should be carefully considered because of the risk of rebleeding and thromboembolic events. In general, aspirin as primary prophylaxis for cardiovascular events and NSAIDs were suggested to be discontinued after LGIB. Managing acute LGIB based on this information would improve clinical outcomes. Further investigations are needed to distinguish patients with LGIB who require early colonoscopy and hemostatic intervention.

关键词： Lower gastrointestinal bleeding Predictive model Colonoscopy Computed tomography Medication

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Influence of contamination on banded iron formations in the Isua supracrustal belt, West Greenland: Reevaluation of the Eoarchean seawater compositions

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Geoscience Frontiers 2018年第4期9卷 1049-1072页

作者： Shogo Aoki Chiho Kabashima Yasuhiro Kato Takafumi hirata Tsuyoshi Komiya Department of Earth Science and Astronomy The University of Tokyo Frontier Research Center for Energy and Resources School of EngineeringThe University of Tokyo Department of Systems Innovation School of EngineeringThe University of Tokyo Ocean Resources Research Center for Next Generation Chiba Institute of Technology Research and Development Center for Submarine Resources Japan Agency for Marine-Earth Science and Technology(JAMSTEC) Division of Earth and Planetary Sciences Kyoto University

Banded Iron Formations（BIFs） are chemical sediments, ubiquitously distributed in the Precambrian supracrustal belts; thus their trace element compositions are helpful for deciphering geochemical evolution on the Earth through time. However, it is necessary to elucidate factors controlling the whole-rock compositions in order to decode the ancient seawater compositions because their compositions are highly variable. We analyzed major and trace element contents of the BIFs in the 3.8-3.7 Ga Isua supracrustal belt（ISB）, southern West Greenland. The BIFs are petrographically classified into four types：Black-,Gray-, Green-and White-types, respectively. The Green-type BIFs contain more amphiboles, and are significantly enriched in Co, Ni, Cu, Zn, Y, heavy rare earth element（HREE） and U contents. However,their bulk compositions are not suitable for estimate of seawater composition because the enrichment was caused by secondary mobility of metamorphic Mg, Ca and Si-rich fluid, involvement of carbonate minerals and silicate minerals of olivine and pyroxene and/or later silicification or contamination of volcanic and clastic materials. The White-type BIFs are predominant in quartz, and have lower transition element and REE contents. The Gray-type BIFs contain both quartz and magnetite. The Black-type BIFs are dominated by magnetite, and contain moderate to high transition element and REE contents. But,positive correlations of V, Ni, Zn and U contents with Zr contents suggest that involvement of detrital,volcanic and exhalative materials influences on their contents. The evidence for significant influence of the materials on the transition element contents such as Ni in the BIFs indicates the transition element contents in the Archean ocean were much lower than previously estimated. We reconstructed secular variations of V,Co, Zn and U contents of BIFs through time, which show Ni and Co contents decreased whereas V, Zn and U contents increased through time. Especially, the Ni

关键词： Banded iron formations Eoarchean Isua supracrustal belt Bioessential elements Seawater compositions

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