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Experimental Study of the Flow in Helical Circular Pipes:Torsion Effect on the Flow Velocity and Turbulence

Journal of Thermal Science 2008年第3期17卷 193-198页

作者： Yasutaka HAYAMIZU Kyoji YAMAMOTO shinichiroYANASE Toru HYAKUTAKE Toru SHINOHARA shinichi morita Department of Mechanical Engineering Yonago National College of Technology Graduate School of Natural Science and Technology Okayama University

An objective of the present paper is to experimentally clarify the torsion effect on the flow in helical circular pipes. We have made six helical circular pipes having different pitches and common non-dimensional curvature δ of about 0.1. The torsion parameter β0, which is defined by β0 = τ/（2δ）1/2 with non-dimensional torsion r, are taken to be 0.02, 0.45, 0.69, 1.01, 1.38 and 1.89 covering from small to very large pitch. The velocity distributions and the turbulence of the flow are measured using an X-type hot-wire anemometer in the range of the Reynolds number from 200 to 20000. The results obtained are summarized as follows： The mean secondary flow pattern in a cross section of the pipe changes from an ordinary twin-vortex type as is seen in a curved pipe without torsion （toroidal pipe） to a single vortex type after one of the twin-vortex gradually disappears as β0 increases. The circulation direction of the single vortex is the same as the direction of torsion of the pipe. The mean velocity distribution of the axial flow is similar to that of the toroidal pipe at small β0, but changes its shape as β0 increases, and attains the shape similar to that in a straight circular pipe when ,β0 = 1.89. It is also found that the critical Reynolds number, at which the flow shows a marginal behavior to turbulence, decreases as ,β0 increases for small ,β0, and then increases after taking a minimum at ,β0 ≈ 1.4 as ,β0 increases. The minimum of the critical Reynolds number experimentally obtained is about 400 at ,β0 ≈ 1.4.

关键词： Helical Circular Pipe Torsion Effect Critical Reynolds Number Turbulence

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Experimental Study of the Viscous Pump with a Helical Channel Rotor:Torsion Effect of the Channel

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Journal of Thermal Science 2010年第2期19卷 154-159页

作者： Yasutaka HAYAMIZU Kyoji YAMAMOTO shinichiro YANASE Toru HYAKUTAKE shinichi morita Shigeru OHTSUKA Department of Mechanical Engineering Yonago National College of Technology4448 Hikona-choYonago-shiTottori 683-8502 Graduate School of Natural Science and Technology Okayama University3-1-1 TushimanakaOkayama-shiOkayama 700-8530

The viscous pump,which has a rotor with a helical square channel,is studied *** non-dimen-sional channel curvature is taken to be about *** types of torsion of the channel are made to investigate the torsion effect on the flow *** measure the flux through the channel at a constant rotor speed by changing the pressures at the entrance and exit of the *** also observe the secondary flow at a cross-section of the *** of the results obtained are shown as follows:The friction factor along the channel to get the same flux is large for large channel torsion at a constant rotation,and becomes small when the favorable rotation of the rotor to the flow is *** for the secondary flow in a cross-section,there appear several types of *** there is no rotation,the secondary flow is almost a symmetric two-vortex type for small flux as is the ordinary Dean vortex,but it changes to a four-vortex type when the flux is *** secondary flow becomes asymmetric as the rotation is *** have unsteady flow patterns at large flux and rotation.

关键词： Viscous Pump Helical Channel Torsion Effect Secondary Flow Flow Visualization Dean Number Taylor Number

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World Journal of Clinical Cases 2019年第21期7卷 3553-3561页

作者： Takeshi Mizusawa Kenya Kamimura Hiroki Sato Takeshi Suda Hiroyuki Fukunari Go Hasegawa Osamu Shibata shinichi morita Akira Sakamaki Junji Yokoyama Yu Saito Yoshihisa Hori Yuduru Maruyama Fumitoshi Yoshimine Takahiro Hoshi shinichi morita Tsutomu Kanefuji Masaaki Kobayashi Shuji Terai Department of Internal Medicine Niigata Prefectural Tokamachi HospitalTokamachiNiigata 948-0065Japan Division of Gastroenterology and Hepatology Graduate School of Medical and Dental SciencesNiigata UniversityNiigata 951-8122Japan Department of Gastroenterology and Hepatology Uonuma Institute of Community Medicine Niigata University HospitalMinami UonumaNiigata 949-7302Japan Department of Surgery Niigata Prefectural Tokamachi HospitalTokamachiNiigata 948-0065Japan Department of Pathology Uonuma Institute of Community Medicine Niigata University HospitalMinami UonumaNiigata 949-7302Japan Department of Internal Medicine Tokamachi Central ClinicTokamachiNiigata 948-0065Japan

BACKGROUND Immunosuppression is effective in treating a number of diseases,but adverse effects such as bone marrow suppression,infection,and oncogenesis are of *** is a key immunosuppressant used to treat rheumatoid *** it is effective for many patients,various side effects have been reported,one of the most serious being methotrexate-related lymphoproliferative *** this may occur in various organs,liver involvement is *** on these liver lesions,including clinical characteristics,course,and imaging studies,has not been summarized to *** SUMMARY We present a case of 70-year-old woman presented with a 2-wk history of fever and abdominal *** had had rheumatoid arthritis for 5 years and was being treated with medication including ***-enhanced computed tomography revealed multiple low density tumors in the liver and the histological analyses showed significant proliferation of lymphocytes in masses that were positive on immunohistochemical staining for CD3,CD4,CD8,and CD79a but negative for CD20 and *** for Epstein-Barr virus-encoded RNA was *** based on these findings,the liver tumors were diagnosed as Methotrexate-related lymphoproliferative disorders.A timedependent disappearance of the liver tumors after stopping methotrexate supported the *** The information obtained from our case and a review of 9 additional cases reported thus far assist physicians who may face the challenge of diagnosing and managing this disorder.

关键词： Arthritis Rheumatoid Methotrexate Malignant lymphoma Case report

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Pulmonary tumor thrombotic microangiopathy of hepatocellular carcinoma: A case report and review of literature

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World Journal of Gastroenterology 2019年第48期25卷 6949-6958页

作者： shinichi morita Kenya Kamimura Hiroyuki Abe Yukari Watanabe-Mori Chiyumi Oda Takamasa Kobayashi Yoshihisa Arao Yusuke Tani Riuko Ohashi Yoichi Ajioka Shuji Terai Division of Gastroenterology and Hepatology Graduate School of Medical and Dental SciencesNiigata UniversityNiigata 951-8510Japan Division of Molecular and Diagnostic Pathology Niigata University Graduate School of Medical and Dental SciencesNiigata UniversityNiigata 951-8510Japan Histopathology Core Facility Niigata University Faculty of MedicineNiigata UniversityNiigata 951-8510Japan

BACKGROUND Pulmonary tumor thrombotic microangiopathy(PTTM)is a rare condition in patients with hepatocellular carcinoma(HCC);to date,few cases have been *** hepatic dysfunction has been focused on the later stages of HCC,the management of symptoms in PTTM is important for supportive care of the *** the better understanding of PTTM in HCC,the information of our recent case and reported cases have been *** SUMMARY A patient with HCC exhibited acute and severe respiratory *** and computed tomography of the chest revealed the multiple metastatic tumors and a frosted glass–like shadow with no evidence of infectious *** diagnosed his condition as acute respiratory distress syndrome caused by the lung metastases and involvement of the pulmonary vessels by tumor *** of prednisolone to alleviate the diffuse alveolar damages including edematous changes of alveolar wall caused by the tumor cell infiltration and ischemia showed mild improvement in his symptoms and imaging *** autopsy showed the typical pattern of PTTM in the lung with multiple *** PTTM is caused by tumor thrombi in the arteries and thickening of the pulmonary arterial endothelium leading to the symptoms of dyspnea in terminal staged ***,supportive management of symptoms is necessary in the cases with PTTM and hence we believe that the information presented here is of great significance for the diagnosis and management of symptoms of PTTM with HCC.

关键词： Pulmonary tumor thrombotic microangiopathy Hepatocellular carcinoma Respiratory dysfunction Prednisolone Supportive care Case report

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Rational arrangement of measuring shear wave speed in the liver

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World Journal of Gastroenterology 2019年第20期25卷 2503-2513页

作者： Takeshi Yokoo Tsutomu Kanefuji Takeshi Suda Itsuo Nagayama Takahiro Hoshi Satoshi Abe shinichi morita Hiroteru Kamimura Kenya Kamimura Atsunori Tsuchiya Masaaki Takamura Kazuyoshi Yagi Shuji Terai Department of Preemptive Medicine for Digestive Diseases and Healthy Active Life Niigata University School of MedicineNiigataNiigata 951-8122Japan Division of Gastroenterology and Hepatology Niigata Tokamachi HospitalTokamachiNiigata 948-0065Japan Department of Gastroenterology and Hepatology Uonuma Institute of Community MedicineNiigata University Medical and Dental HospitalMinami UonumaNiigata 949-7302Japan Division of Gastroenterology and Hepatology Graduate School of Medical and Dental SciencesNiigata UniversityNiigata 951-8122Japan

BACKGROUND Shear wave speed has been widely applied to quantify a degree of liver fibrosis. However, there is no standardized procedure, which makes it difficult to utilize the speed universally. AIM To provide procedural standardization of shear wave speed measurement. METHODS Point shear wave elastography (pSWE) was measured in 781 patients, and twodimensional shear wave elastography (2dSWE) was measured on the same day in 18 cases. Regions-of-interest were placed at 12 sites, and the median and robust coefficient-of-variation (CVR) were calculated. A residual sum-of-square (Σdi2) was computed for bootstrap values of 1000 iterations in 18 cases with each assumption of 1 to 12 measurements. The proportion of the Σdi2 (%Σdi2) was calculated as the ratio of Σdi2 to pSWE after converting it based on the correlation between pSWE and 2dSWE. RESULTS The CVR showed a significantly broader distribution in the left lobe (P < 0.0001),and the smallest CVR in the right anterior segment that covered 95% cases was 40.4%. pSWE was significantly higher in the left lobe than in the right lobe (1.63 ± 0.78 m/s vs 1.61 ± 0.78 m/s, P = 0.0004), and the difference between the lobes became further discrete when the subjects were limited to the cases with a CVR less than 40.4% in any segment (1.76 ± 0.80 m/s vs 1.70 ± 0.82 m/s, P < 0.0001). The highest values of the CVR in every 0.1 m/s interval were plotted in convex upward along pSWE and peaked at 1.93 m/s. pSWE and 2dSWE were significantly correlated (P < 0.0001, r = 0.95). In 216000 resamples from 18 cases, the %Σdi2 of 12 sites was 8.0% and gradually increased as the acquisition sites decreased to reach a significant difference with a %Σdi2 of 7 sites (P = 0.027). CONCLUSION These data suggest that shear wave speed should be measured at 8 or more sites of spreading in both lobes.

关键词： Liver stiffness Ultrasound Shear wave elastography Acoustic radiation force impulse Heterogeneity

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Gravity assistance enables liver stiffness measurements to detect liver fibrosis under congestive circumstances

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World Journal of Hepatology 2022年第4期14卷 778-790页

作者： Takeshi Suda Ai Sugimoto Tsutomu Kanefuji Atsushi Abe Takeshi Yokoo Takahiro Hoshi Satoshi Abe shinichi morita Kazuyoshi Yagi Masashi Takahashi Shuji Terai Department of Gastroenterology and Hepatology Uonuma Institute of Community MedicineNiigata University Medical and Dental HospitalMinami Uonuma 949-7302NiigataJapan Division of Thoracic and Cardiovascular Surgery Graduate School of Medical and Dental SciencesNiigata UniversityNiigata 951-8122Japan Department of Gastroenterology and Hepatology Tsubame Rosai HospitalTsubame 959-1228NiigataJapan Department of Administration Joetsu-Area General Health Care CenterJoetsu 943-0803NiigataJapan Department of Preemptive Medicine for Digestive Diseases and Healthy Active Life Niigata University School of MedicineNiigata 951-8122Japan Division of Gastroenterology and Hepatology School of Medical and Dental SciencesNiigata UniversityNiigata 951-8122Japan

BACKGROUND As survival has been prolonged owing to surgical and medical improvements,liver failure has become a prognostic determinant in patients with congestive heart *** hepatopathy,an abnormal state of the liver as a result of congestion,insidiously proceed toward end-stage liver disease without effective biomarkers evaluating pathological *** measurements of shear wave elastography cannot qualify liver fibrosis,which is a prognosticator in any type of chronic liver disease,in cases of congestion because congestion makes the liver stiff without *** hypothesized that the effects of congestion and fibrosis on liver stiffness can be dissociated by inducing architectural deformation of the liver to expose structural *** establish a strategy measuring liver stiffness as a reflection of architectural rigidity under *** Two-dimensional shear wave elastography(2dSWE)was measured in the supine(Sp)and left decubitus(Ld)positions in 298 consecutive cases as they were subjected to an ultrasound study for various liver *** of interest were placed at twelve sites,and the median and robust coefficient of variation were *** data were compared using the Mann-Whitney U or Kruskal-Wallis test followed by Dunn's post-hoc multiple *** inferior vena cava(IVC)diameters at different body positions were compared using the Wilcoxon matched pairs signed rank *** number of cases with cardiothoracic ratios greater than or not greater than 50%was compared using Fisher’s exact test.A correlation of 2dSWE between different body positions was evaluated by calculating Spearman correlation *** The IVC diameter was significantly reduced in Ld in subjects with higher 2dSWE values in Ld(LdSWE)than in Sp(SpSWE)(P=0.007,(average±SD)13.9±3.6 vs 13.1±3.4 mm)but not in those with lower LdSWE values(P=0.32,13.3±3.5 vs 13.0±3.5 mm).In 81 subjects,SpSWE was increased or decreased in

关键词： Shear wave elastography Inferior vena cava diameter Congestive hepatopathy Liver fibrosis Body positions Fibrosis-4 index

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A Micromixer Using the Chaos of Secondary Flow: Rotation Effect of Channel on the Chaos of Secondary Flow

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Open Journal of Fluid Dynamics 2012年第4期2卷 195-201页

作者： Yasutaka Hayamizu shinichiro Yanase shinichi morita Shigeru Ohtsuka Takeshi Gonda Kazunori Nishida Kyoji Yamamoto Department of Mechanical Engineering Yonago National College of Technology Tottori Japan Graduate School of Natural Science and Technology Okayama University Okayama Japan

The micromixer, which has a rotor with a curved channel, is studied experimentally. The secondary flow in a curved channel of rectangular cross-section is investigated using PIV (Particle Image Velocimetry) and LIF (Laser Induced Fluorescence) methods. Two walls of the channel (the inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction of the exit of the channel. The non-dimensional channel curvature δ=a/R is taken to be about 0.1, where 2a is the width of the channel, R the curvature radius of the channel. Other non-dimensional parameters concerned are the Dean number De=Reδ1/2, the Reynolds number Re=qdh/v, where q is the mean flow velocity in the channel axis direction, ν the kinematic viscosity, dh the hydraulic diameter of the channel, and the Taylor number Tr=2(2δ)1/2Ωa2/(δv), where Ω is the angular velocity of the rotor. Photographs of the flow in a cross-section at 180° downstream from the curved channel entrance are taken by changing the flux (De) at a constant rotational speed (Tr) of the channel walls. It is found that good mixing performance is obtained in the case of De≤0.1|Tr| and for that case secondary flows show chaotic behaviors. And then we have confirmed the occurrence of reversal of the mean axial flow.

关键词： Chaos Rotation Effect Secondary Flow PIV LIF

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A Micromixer Using the Taylor-Dean Flow: Effect of Inflow Conditions on the Mixing

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Open Journal of Fluid Dynamics 2014年第5期4卷 463-471页

作者： Toshihiko Kawabe Yasutaka Hayamizu shinichiro Yanase Takeshi Gonda shinichi morita Shigeru Ohtsuka Kyoji Yamamoto Technical Division Tsurumi Manufacturing Co. Ltd. Tottori Japan Department of Mechanical Engineering Yonago National College of Technology Tottori Japan Graduate School of Natural Science and Technology Okayama University Okayama Japan

Chaotic mixing in a curved-square channel flow is studied experimentally and numerically. Two walls of the channel (inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction toward the exit of the channel. This flow is a kind of Taylor-Dean flows. There are two parameters dominating the flow, the Dean number De (∝ the pressure gradient or the Reynolds number) and the Taylor number Tr (∝ the angular velocity of the wall rotation). In the present paper, we analyze the physical mechanism of chaotic mixing in the Taylor-Dean flow by comparing experimental and numerical results. We produced a micromixer model of the curved channel several centimeters long with square cross section of a few millimeters side. The secondary flow was measured using laser induced fluorescence (LIF) method to examine secondary flow characteristics. We also performed three-dimensional numerical simulations for the exactly same configuration as the experimental system to study the mechanism of chaotic mixing. It is found that good mixing performance is achieved for the case of De ≤ 0.1Tr, and that mixing efficiency changes according to the difference in inflow conditions. The flow is studied both experimentally and numerically, and both results agree with each other very well.

关键词： Taylor-Dean Flow Chaotic Mixing Secondary Flow LIF CFD

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A Micromixer Using the Taylor-Dean Flow: Effects of Aspect Ratio and Inflow Condition on the Mixing

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Open Journal of Fluid Dynamics 2015年第3期5卷 256-264页

作者： Yasutaka Hayamizu Toshihiko Kawabe shinichiro Yanase Takeshi Gonda shinichi morita Shigeru Ohtsuka Kyoji Yamamoto Department of Mechanical Engineering Yonago National College of Technology Tottori Japan Technical Division Tsurumi Manufacturing Co. Ltd. Tottori Japan Graduate School of Natural Science and Technology Okayama University Okayama Japan

Chaotic mixing in three different types of curved-rectangular channels flow has been studied experimentally and numerically. Two walls of the channel (inner and top walls) rotate around the center of curvature and a pressure gradient are imposed in the direction toward the exit of the channel. This flow is a kind of Taylor-Dean flow. There are two parameters dominating the flow, the Dean number De (∝ the pressure gradient or the Reynolds number) and the Taylor number Tr (∝ the angular velocity of the wall rotation). In this paper, we analyze the physical mechanism of chaotic mixing in the Taylor-Dean flow by comparing experimental results and numerical ones. We produced three micromixer models of the curved channel, several centimeters long, with rectangular cross-section of a few millimeters side. The secondary flow is measured using laser induced fluorescence (LIF) method to examine secondary flow characteristics. Also we performed three-dimensional numerical simulations with the open source CFD solver, OpenFOAM, for the same configuration as the experimental system to study the mechanism of chaotic mixing. It is found that good mixing performance is obtained in the case of De ≤ 0.1 Tr, and it becomes more remarkable when the aspect ratio tends to large. And it is found that the mixing efficiency changes according to the aspect ratio and inflow condition.

关键词： Component Taylor-Dean Flow Chaotic Mixing Secondary Flow LIF CFD

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A 92-year-old man with retropharyngeal hematoma caused by an injury of the anterior longitudinal ligament

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Chinese Journal of Traumatology 2010年第2期13卷 120-122页

作者： Seiji morita shinichi lizuka Haruna Hirakawa Shigeo Higami Takeshi Yamagiwa Sadaki Inokuchi Department of Emergency and Critical Care Medicine Tokai University School of Medicine 143 Shimokasuya Isehara-City Kanagawa 2591193 Japan

Traumatic retropharyngeal hematoma is a rare condition and may be lethal in some cases. In patients with this condition, the absence of a vertebral fracture or a major vascular injury is extremely rare. We present the case of a 92-year-old man who hit his forehead by slipping on the floor in his house. He had no symptoms at the time; however, he experienced throat pain and dyspnea at 6 hours after the injury. On arrival, he complained of severe dyspnea; therefore, an emergency endotracheal intubation was performed. A lateral neck roentgenogram after intubation showed dilatation of the retropharyngeal and retrotracheal space and no evidence of a cervical vertebral fracture. Cervical computed tomography （CT） with contrast medium revealed a massive hematoma extending from the retropharyngeal to the superior mediastinal space but no evidence of contrast medium extravasation or a vertebral fracture. However, sagittal magnetic resonance imaging （MRI） revealed an anterior longitudinal ligament （C4-5 levels） injury. We determined that the cause of the hematoma was an anterior longitudinal ligament injury and a minor vascular injury around the injured ligament. Therefore, we recommend that patients with retropharyngeal hematoma undergo sagittal cervical MRI when roentgenography and CT reveal no evidenee of injury.

关键词： Hematoma Longitudinal ligaments Cervical vertebrae Magneticresonance imaging

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