• Title/Summary/Keyword: Blood flow area

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CFD Analysis on Stent Shape to Reduce Blood Flowing into Cerebral Aneurysm (뇌동맥류 혈액유입 저감을 위한 스텐트 형상에 관한 전산유체해석)

  • Yeo, Dong-Hyeon;Park, Dong-Gyu;Byon, Sang-Min
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.1
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    • pp.42-50
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    • 2017
  • A cerebral aneurysm is a ballooning arising from a weakened area in the wall of a blood vessel in the brain. In this study, the flow analysis of the blood vessel, including the cerebral aneurysm and the stent, was conducted to investigate the effect of the stent shape on reduction of blood flowing into the cerebral aneurysm. We used the Carreau model to describe Non-Newtonian behaviors of blood flow. Two kinds of stents, which had different cross angles were modelled by the commercial CAD program and the geometries of those stents were reflected in the analysis domain of the blood vessel. From the results of the flow analysis, we found that the blood flowing into the cerebral aneurysm was decreased as the cross angle of the stent was decreased.

Development of Laser Speckle Flowgraphy System for Monitoring Blood Flow in Skin Tissue (레이저 산란 현상을 이용한 피부혈류 화상화 시스템의 개발)

  • Lee, M.C.;Fujii, H.
    • Journal of Biomedical Engineering Research
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    • v.28 no.3
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    • pp.392-396
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    • 2007
  • In this paper, we develop a new system to visualize the blood flow map in skin tissue, using the technique of Laser Speckle Flowgraphy (LSFG). The measuring unit consists of the laser diode, imaging system, line sensor, scanning mirror, and one-board microcomputer. The speckle signal is analyzed and sent to a PC, where the blood flow in a tissue area of $14mm{\times}26 mm$ is evaluated and displayed in a 2-D color map. It is demonstrated that the new LSFG instrument is useful to evaluate the degree of allergic reaction in patch test.

The Change of Blood Flow Velocity of Radial Artery after Linear Polarized Infrared Light Radiation near the Stellate Ganglion: Comparing with the Stellate Ganglion Block (성상신경절 부위의 직선편광 근적외선 조사 후 요골동맥에서의 혈류속도의 변화: 성상신경절 차단술과의 비교)

  • Han, Soung-Moon;Lee, Sang-Chul
    • The Korean Journal of Pain
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    • v.14 no.1
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    • pp.37-40
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    • 2001
  • Background: It had been reported by authors that linear polarized infrared light radiation (Superizer: SL) near the stellate ganglion had a similar effect on the change of skin temperature of hand compared with the stellate ganglion block (SGB). We hypothesized that this was due to dilatation of vessels and an increased blood flow. The aim of this study was to measure the velocity of blood flow in peripheral vessels after linear polarized infrared light radiation near the stellate ganglion and to compare the effect of SL with that of SGB using local anesthetics. Methods: Forty patients whose clinical criteria were matched for the symptoms of SGB were selected for study. We radiated the stellate ganglion by linear polarized infrared light radiation and measured the blood flow of radial artery using Ultrasound Doppler blood flow meter before and after 10, 20 and 30 minutes post-radiation. After 3 days, SGB was performed using 8 ml of 1% mepivacaine to the same patient, and the radial artery blood flow was measured in the same manner. Results: The blood flow velocity was increased by 40% and 27% at 10 min and 20 min after SL and by 42% and 41% at 10 min and 20 min after SGB. However, there was no statistically significant difference in blood flow velocity between SGL and SGB. Conclusions: We could conclude that linear polarized radiation is a clinically simple and useful noninvasive therapeutic tool in clinical area.

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Fluid-Structure Interaction Analysis of Blood Vessel Considering Internal Diameter Variation (내부직경 변화를 고려한 혈관의 유체-구조 상호작용 해석)

  • Octavianty, Ressa;Kim, Dong-Hyun;Kim, Su-Hyun;S. Nababan, Boyke;Byun, Jun-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.959-963
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    • 2006
  • A three-dimensional elastic blood vessel model with internal diameter variation is considered to investigate internal flow characteristics and effects of structural deformation. Also, computational analyses for both the rigid model and the fully-coupled FSI model have been conducted in order to compare the shear stress, pressure distribution, and flow velocity in detail. A 70% narrowing area of asymmetric blood vessel model was especially investigated to show the versatility of fluid-structure interaction phenomenon. The results reveal that effect of fluid-structure interaction is very important to accurately investigate the flow characteristics of the blood vessel.

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A microscopic study on the rheological properties of human blood in low concentration limit

  • Kang, In-Seok
    • Korea-Australia Rheology Journal
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    • v.14 no.2
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    • pp.77-86
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    • 2002
  • A microscopic theoretical study is performed to predict the rheological properties of human blood in the low concentration limit. The shear thinning behavior of blood in the low shear limit is studied by considering the aggregate formation of red blood cells, which is called the rouleaux formation. Then the constitutive equations of blood in the high shear limit are derived for various flow situations by considering the unique features of deformation of blood cells. Specifically, the effects of the surface-area-preserving constraint and the lank-treading motion of blood cells on the rheological properties are studied.

Analysis of Blood Flow Interacted with Leaflets in MHV in View of Fluid-Structure Interaction

  • Park, Choeng-Ryul;Kim, Chang-Nyung
    • Journal of Mechanical Science and Technology
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    • v.15 no.5
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    • pp.613-622
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    • 2001
  • Interaction of blood flow and leaflet behavior in a bileaflet mechanical heart valve was investigated using computational analysis. Blood flows of a Newtonian fluid and a non-Newtonian fluid with Carreau model were modeled as pulsatile, laminar, and incompressible. A finite volume computational fluid dynamics code and a finite element structure dynamics code were used concurrently to solve the flow and structure equations, respectively, where the two equations were strongly coupled. Physiologic ventricular and aortic pressure waveforms were used as flow boundary conditions. Flow fields, leaflet behaviors, and shear stresses with time were obtained for Newtonian and non-Newtonian fluid cases. At the fully opened phase three jets through the leaflets were found and large vortices were present in the sinus area. At the very final stage of the closing phase, the angular velocity of the leaflet was enormously large. Large shear stress was found on leaflet tips and in the orifice region between two leaflets at the final stage of closing phase. This method using fluid-structure interaction turned out to be a useful tool to analyze the different designs of existing and future bileaflet valves.

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Effects of Different Sizes of Blood Flow Restriction Areas on Changes in Muscle Thickness

  • Park, Jae-Cheol;Park, Mi-Sook;Kim, Yong-Nam
    • The Journal of Korean Physical Therapy
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    • v.29 no.2
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    • pp.80-84
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    • 2017
  • Purpose: This study was conducted to examine the effects of different sizes of blood flow restriction areas on the thickness of the external oblique and biceps brachii. Methods: The study subjects were 52 adults who were divided into four groups that performed plank exercises over a six-week period after blood flow restriction. Changes in the thickness of the external oblique and biceps brachii were measured using ultrasonography before the experiment, then three and six weeks after the experiment. The changes in each variable over time were evaluated by repeated-measures analysis of variance (ANOVA). Results: The external oblique and biceps brachii showed significant differences in muscle thickness with regard to time and the interaction between time and each group (p<0.01), but no significant differences with regards to changes between groups (p>0.05). Conclusion: A larger blood flow restriction area resulted in a statistically significant increase in muscle thickness. The results of this study may be used as the basis for future studies and for rehabilitation in clinical practice.

The use of the buccal fat pad for guided bone regeneration in posterior maxilla: Review of the literature and report of 2 cases (상악 구치 부에서 골계생술시 협지방체를 이용한 연조직 피개 : 문헌 고찰 및 증례보고)

  • Sung, Hun-Mo
    • The Journal of the Korean dental association
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    • v.47 no.3
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    • pp.122-130
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    • 2009
  • For the successful guided bone regeneration(GBR) of maxillary bony defect, proper soft tissue coverage is one of the most important things. Soft tissue dehiscence can be most common reason of osseous reconstruction failure. If a vascular supply to the graft should not develop from the host tissue, then the graft may also foil. Both of these prerequisites can be aided by judicious use of the buccal fat pad(BFP). Many methods for adequate soft tissue coverage have been proposed and the use of the BFP is one of them. BFP is useful in posterior maxillary area, can cover larger area and have higher blood flow than other methods. so the use of the BFP may offer protection and early blood supply to maxillary bone graft. This report describes the history, anatomy, blood flow, and clinical usefulness with two clinical cases.

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The Numerical study for flow characteristics of bifurcation in blood vessel (혈관 분지부의 유동 특성에 대한 수치해석 연구)

  • Lee, In-Sub;Ryou, Hong-Sun
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.741-746
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    • 2003
  • The main objective of present study is to obtain information for flow characteristics, such as velocity and wall shear stress, of bifurcation in blood vessel. Branch flows for Newtonian fluids are simulated by using Fluent V.6.0. The numerical simulations are carried out for five cases divided by different values of bifurcation angle and area ratio. As a result of simulation, high wall shear stress is appeared at the bifurcated region. As increasing bifurcation angle, pressure drop is increasing. In addition, as the area is decreasing, pressure drop and wall shear stress is increasing.

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Effects of stenotic severity on the flow structure in a circular channel under a pulsatile flow

  • Kim, Kyung-Won;Cheema, Taqi-Ahmad;Park, Cheol-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.2
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    • pp.140-146
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    • 2014
  • Stenosis is the drastic reduction in the cross-sectional area of blood vessel caused by accumulations of cholesterol. It affects the blood flow property and structure from the fluid dynamic point of view. To understand the flow phenomenon more clearly, a particle image velocimetry method is used and the fluid dynamic characteristics in a circular channel containing stenosis structure is investigated experimentally in this study. Different stenotic-structured models made of acrylic material are subjected to a pulsatile flow generated by an in-house designed pulsatile pump. The inner diameter of the tube inlet is 20 mm and the length of reduced area for stenosis ranges between 35mm and 40mm. It is circulated continuously through a circular channel by the pump system. Pressure is measured at four different sections during systolic and diastolic phase changes. The phase-averaged velocity field distribution shows a recirculation regime after the stenotic structure. The effects of the stenotic obstructions are found to be more severe when the aspect ratio is varied.