• Title/Summary/Keyword: Constriction

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Fluid-structure interactions of physiological flow in stenosed artery

  • Buriev, Bahtiyor;Kim, Tae-Dong;Seo, Tae-Won
    • Korea-Australia Rheology Journal
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    • v.21 no.1
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    • pp.39-46
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    • 2009
  • Atherosclerosis is a disease that narrows, thickens, hardens, and restructures a blood vessel due to substantial plaque deposit. The geometric models of the considered stenotic blood flow are three different types of constriction of cross-sectional area of blood vessel; 25%, 50%, and 75% of constriction. The computational model with the fluid-structure interaction is introduced to investigate the wall shear stresses, blood flow field and recirculation zone in the stenotic vessels. The velocity profile in a compliant stenotic artery with various constrictions is subjected to prescribed physiologic waveform. The computational simulations were performed, in which the physiological flow through a compliant axisymmetric stenotic blood vessel was solved using commercial software ADINA 8.4 developed by finite element method. We demonstrated comparisons of the wall shear stress with or without the fluid-structure interaction and their velocity profiles under the physiological flow condition in the compliant stenotic artery. The present results enhance our understanding of the hemodynamic characteristics in a compliant stenotic artery.

A study on quantitative risk assessment of mechanical accidents (사업장의 기계재해 위험성평가에 관환 연구)

  • Han, Ou-Sup
    • Journal of the Society of Disaster Information
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    • v.5 no.2
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    • pp.140-152
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    • 2009
  • Recently the occurrence ratio of mechanical accidents in industrial disaster of korea is increased, but very little accident information has been given regarding the prevention of mechanical accidents. In this study, mechanical accidents by the analysis of industrial accident case was examined. And it was proposed the risk assessment method and building database for investigation of risk factors in mechanical accident. As a result, from mechanical accidents database, it was found that the occurrence ratio of mechanical accident by constriction and falling etc. is very high and death ratio by mechanical accident is larger than that of usual accident. And we applied the quantitative risk assessment method proposed by this study in the mechanical accident analysis of a domestic manufacturer. From the results, the risk factors due to constriction, curling, falling and scattering are principal causes of mechanical accidents. These result is similar to that of the analysis of mechanical accidents for recent 12 years in korea.

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Electromyographic Study of the Sternohyoid Muscle to Control an Electrolarynx (인공후두 제어원으로서의 흉골설골근 사용의 타당성 검증)

  • 민혜정;봉정표
    • Journal of Biomedical Engineering Research
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    • v.17 no.2
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    • pp.201-208
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    • 1996
  • We have been studying an implant type EMG-controlled electrolarynx. First of all, we propose the sternohyoid muscle(SH) as a control source of the electrolarynx. The purpose of this study is to investigate the possibility that subjects control voluntarily the constriction of their SH, and produce the control signals of electrolarynx. For this pwnan, we carried out four experiments regarding the control of the electrolarynx. At the results, we found that subjects can control the start/stop of constriction and the amplitude of EMG of their SH. Also, we ascertained the possibility that the start/stop of contraction of SH controls OW/OFF of sound source of the electrolarynx and the amplitude of UG of SH controls the pitch frequency of the electrolarynx.

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Surgical Correction of Obstruction of the Inferior Vena Cava using Profound Hypothermia and Total Circulatory Arrest - A Case Report - (초 저체온법과 전혈류 정지술을 이용한 하공정맥 폐쇄증의 수술 치험: 1례 보고)

  • 유재현
    • Journal of Chest Surgery
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    • v.24 no.7
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    • pp.732-738
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    • 1991
  • Membranous obstruction of the inferior vena cava[IVC] is a rare congenital anomaly that may present clinical features of Budd-Chiari syndrome caused by chronic obstruction of hepatic drain. We have experienced a case of IVC obstruction caused by hour-glass constriction and membrane in its center. Operative correction was accomplished using profound hypothermia [20%] and total circulatory arrest of 26 minutes. This technique permitted resection of membrane with direct vision and removal of thrombus of IVC and hepatic vein. After then constricted IVC was repaired with autologous pericardial patch. Total circulatory arrest was used intermittently for good visual field. Postoperative course was smooth and postoperative angiography showed unobstructed flow through the IVC in spite of slight constriction of cavoatrial junction and nearly complete disappearance of collateral vessels.

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Karyotype Analysis of Lilium cernum Komrov by Means of C-banding Method (Giemsa 분염법에 의한 솔나리의 핵형 분석)

  • 손진호
    • Journal of Plant Biology
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    • v.21 no.1_4
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    • pp.29-32
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    • 1978
  • The karyotype of Lilium cernum has been analysed by means of C-banding technique. Most of clones observed were 2n=24 chromosomes which consist of two pairs of submetacentric and ten pairs of subtelocentric chromosomes, among which two pairs of chromosomes(B and E) showed secondary constriction in the short arm. In addition to these chromosomes a small supernumerary telocentric chromosome was seen in the eight clones. Sixtyeight bands were observed in the twentytwo chromosomes of complement and one band in the supernumerary chromosome. A pair of chromosome (L) did not show any band. The bnads on the chromosome. A pair of chromosome (L) did not show any band. The bands on the chromosomes were distributed in the centromere, secondary constriction and intercalary regions of arms. Of the twelve pairs of chromosomes ten pairs showed symmetric banding patterns in each, but two pairs (I and K) showed asymmetric banding patterns.

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C-to-V coarticulation in horizontal and vertical dimensions and its implications for phonology

  • Lee, Joo-Kyeong
    • Speech Sciences
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    • v.7 no.4
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    • pp.107-121
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    • 2000
  • In this paper, I investigate the acoustic correlates of a vowel's coarticulatory dynamics manifested in preceding and following consonants along two dimensions of the vocal tract: place of articulation and degree of constriction. Two dimensional coarticulation is not necessarily executed either concomitantly or proportionally, and the modification induced by coarticulation with a vowel in CVC structures is merely restricted to the CV portion; that is, the prevocalic consonant is modified solely in its constriction location. This is consistent with the observation that C-to-V place assimilation does not accompany consonant lenition in phonology, which suggests that phonetic nature is effectively reflected in phonological patterns.

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Effect of Mitomycin C on Chinese Hamster Cells (培養한 Chinese Hamster 細胞에 미치는 Mitomycin C 의 影響)

  • Hahn, Sahsook
    • The Korean Journal of Zoology
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    • v.16 no.4
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    • pp.211-217
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    • 1973
  • Mitomycin C, chemically reactive antibiotics derived from Streptomyces caespitosus, was introduced to Chinese hamster, Cricetulus griseus, (2n=22) cells (22Emb. ♀5PSP ♂, to carry out an analysis of the chromosome aberration. It was found that regions 5 and 7 of chromosomes 1 and 2, and secondary constriction of chromosome X showed the most striking effect of Mitomycin C. The relationship between Mitomycin C and secondary contriction was discussed.

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Curcumin Attenuates Chronic Constriction Nerve Injury-Induced Neuropathic Pain in Rats (Curcumin의 신경병증성 통증 억제효과)

  • Kim, Chae-Eun;Park, Eun-Sung;Jeon, Young-Hoon
    • Korean Journal of Medicinal Crop Science
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    • v.16 no.3
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    • pp.183-187
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    • 2008
  • Nerve injury can lead to neuropathic pain, which is often resistant to current analgesics and interventional therapeutic methods. Extracellular signal-regulated kinase (ERK) plays important role in the induction of neuropathic pain. We explored the antinociceptive effect of curcumin and its effect on ERK in the spinal cord in the neuropathic pain model of rats induced by chronic constriction injury (CCI) of the sciatic nerve. In injured rats, mechanical allodynia, which is one of characteristics of neuropathic pain developed and the activation of ERK in spinal cord significantly increased compared with control group. However, administration of curcumin (50 mg/kg/day p.o) for 7 days started from one day before the injury prevented the development of mechanical allodynia and increase of ERK phosphorylation. These results indicate that curcumin can be a new therapeutic agent in the treatment of neuropathic pain.

Estimation of Real Area of Contact and Lubrication Regimes using Electric Contact Resistance (전기 저항을 이용한 실접촉 면적과 윤활 영역의 예측)

  • 이홍철;김대은
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.11a
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    • pp.11-17
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    • 2000
  • The electric contact resistance between ball and disk was measured to estimate the real area of contact under dry and lubrication conditions. The results from the measured constriction resistance using the hypothesis of a single circular contact was compared with those of Hertzian contact theory and hardness. The resistance correlated well with the asperity contact area and friction when the ball slides on the flat disk spreaded with lubricant film. Therefore, the constriction resistance method was useful to identify the lubrication regimes with respect to various loads and speeds. The results of this work will aid in better prediction of lubrication regimes with respect to the operating conditions.

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