• Title/Summary/Keyword: disturbed flow

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Coronary Artery Bypass Graft (CABG) for Intracavitary Coronary Artery Disease - A case report- (심강내관상동맥(Intracavitary Coronary Artery)질환에 대한 관상동맥우회술 -수술치험 1예-)

  • Kim Su-Wan;Sung Kiick;Park Pyo Won;Jun Tae-Gook;Park Kay-Hyun;Lee Young Tak
    • Journal of Chest Surgery
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    • v.38 no.7 s.252
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    • pp.504-506
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    • 2005
  • Intracavitary coronary artery is variant anomalous entrance to right ventricular cavity of left anterior descending artery. Since the disease is extremely rare, there has not been any report of it in Korea and is only found in $0.2\~0.3\%$ of all CABG patients. It is very difficult to be diagnosed by preoperative coronary arteriography (CAG) and secure suture is needed for right ventriculotomy after CABG due to bleeding from right ventricle. Horizontal mattress suture with pledget has been recommended but, it could compress the myocardium surrounding ventriculotomy and result in disturbed flow of left anterior descending artery branch and perforating artery. So we used simple interrupted suture and the patient was recovered as other CABG patients without complications.

Numerical Study on the Characteristics of Thermal Plasmas Disturbed by Inserting a Langmuir Probe (랑뮤어 탐침에 의해 변형된 열플라즈마 특성에 관한 해석적 연구)

  • Lee, J.C.;Kim, Y.J.
    • Journal of the Korean Vacuum Society
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    • v.17 no.3
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    • pp.189-194
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    • 2008
  • Measurements with a Langmuir probe, which are the most often used procedures of plasma diagnostics, can disturb plasma flows and change its characteristics quite a little because the probe should be inserted into thermal flowing plasmas. In this study, we calculated the characteristics of thermal plasmas with and without the probe into an atmospheric argon free-burning arc numerically, and investigated aerodynamic and thermal disturbances with temperature and axial velocity distributions. For the modelling of thermal plasmas, we have made two governing equations, which are on the thermal-flow and electromagnetic fields, coupled together with a commercial CFD package and user-coded subroutines. It was found that thermal disturbances happened to both sides of the probe, before and behind, seriously. Due to the aerodynamic disturbance, we could find that there were the stagnation point in front of the probe and the wake behind it. Therefore, aerodynamic and thermal disturbances caused by the probe insertion should be considered to increase the reliability of the probe diagnostics.

Estimation of the zone of excavation disturbance around tunnels, using resistivity and acoustic tomography

  • Suzuki Koichi;Nakata Eiji;Minami Masayuki;Hibino Etsuhisa;Tani Tomonori;Sakakibara Jyunichi;Yamada Naouki
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.62-69
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    • 2004
  • The objective of this study is to estimate the distribution of a zone disturbed by excavation (EDZ) around tunnels that have been excavated at about 500 m depth in pre-Tertiary hard sedimentary rock. One of the most important tasks is to evaluate changes in the dynamic stability and permeability of the rock around the tunnels, by investigating the properties of the rock after the excavation. We performed resistivity and acoustic tomography using two boreholes, 5 m in length, drilled horizontally from the wall of a tunnel in pre-Tertiary hard conglomerate. By these methods, we detected a low-resistivity and low-velocity zone 1 m in thickness around the wall of the tunnel. The resulting profiles were verified by permeability and evaporation tests performed at the same boreholes. This anomalous zone matched a high-permeability zone caused by open fractures. Next, we performed resistivity monitoring along annular survey lines in a tunnel excavated in pre-Tertiary hard shale by a tunnel-boring machine (TBM). We detected anomalous zones in 2D resistivity profiles surrounding the tunnel. A low-resistivity zone 1 m in thickness was detected around the tunnel when one year had passed after the excavation. However, two years later, the resistivity around the tunnel had increased in a portion, about 30 cm in thickness, of this zone. To investigate this change, we studied the relationship between groundwater flow from the surroundings and evaporation from the wall around the tunnel. These features were verified by the relationship between the resistivity and porosity of rocks obtained by laboratory tests on core samples. Furthermore, the profiles matched well with highly permeable zones detected by permeability and evaporation tests at a horizontal borehole drilled near the survey line. We conclude that the anomalous zones in these profiles indicate the EDZ around the tunnel.

The Literature Review of FibroMyalgia Syndrome (섬유근통 증후군에 대한 문헌고찰)

  • Kim Myung-Chul;Kim Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.16 no.4
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    • pp.23-37
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    • 2004
  • Fibromyalgia syndrome(FMS) is a chronic pain disorder of unknown etiology characterized by widespread musculoskeletal aches and pains, stiffness, and general fatigue, disturbed sleep and sleepiness. Frequently misdiagnosed, FMS is often confused with myofascial pain syndrome, polymyalgia rheumatica, polymyositis, hypothyroidism, metastatic carcinoma, rheumatoid arthritis (RA), juvenile rheumatoid arthritis, chronic fatigue syndrome, or systemic lupus erythematosus, any of which may occur concomitantly with FMS. The management of FMS often begins with a thorough examination and a diagnosis from a physician who is formally trained in tender-point/trigger-point recognition. An initial diagnosis provides reassurance to the patient and often reduces the anxiety and depression patterns associated with FMS. The most common goals in the management of FMS are (1) to break the pain cycle, (2) to restore sleep patterns, and (3) to increase functional activity levels. Because FMS is a multifactorial syndrome, it is likely that the best treatment will encompass multiple strategies. Medication with analgesics and antidepressants and also physiotherapy, are often prescribed and give some relief. The other most effective intervention for long-term management of FS to date is physical exercise. Physical therapists can instruct patients in the use of heat at home (moist hot packs, heating pads, whirlpools, warm showers or baths, and hot pads) to increase local blood flow and to decrease muscle spasm and tension. Also instruct patients in the proper use of cold modalities (ice packs, ice massage, and cool baths) to anesthetize localized areas of pain (tender points) and break the pain cycle. Massage and tender-point massage also may promote muscle relaxation. To date, the two most important interventions for the long-term management of FS are patient education and physical exercise. Lately, is handling FMS and Chronic Fatigue syndrome(CFS) together, becuase FMS and CFS are poorly understood disorders that share similar demographic and clinical characteristics. Because of the clinical similarities between both disorders it was suggested that they share a common pathophysiological mechanism, namely, central nervous system dysfunction.

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Neutron Noise Analysis for PWR Core Motion Monitoring (중성자 잡음해석에 의한 PWR 노심 운동상태 감시)

  • Yun, Won-Young;Koh, Byung-Jun;Park, In-Yong;No, Hee-Cheon
    • Nuclear Engineering and Technology
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    • v.20 no.4
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    • pp.253-264
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    • 1988
  • Our experience of neutron noise analysis in French-type 900 MWe pressurized water reactor (PWR) is presented. Neutron noise analysis is based on the technique of interpreting the signal fluctuations of ex-core detectors caused by core reactivity changes and neutron attenuation due to lateral core motion. It also provides advantages over deterministic dynamic-testing techniques because existing plant instrumentation can be utilized and normal operation of the plant is not disturbed. The data of this paper were obtained in the ULJIN unit 1 reactor during the start-up test period and the statistical descriptors, useful for our purpose, are power spectral density (PSD), coherence function (CF), and phase difference between detectors. It is found that core support barrel (CSB) motions induced by coolant flow forces and pressure pulsations in a reactor vessel were indentified around 8 Hz of frequency.

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A Clinical study of Paranasal Sinusitis (副鼻洞炎에 關한 臨床的 硏究)

  • Choi, In-hwa;Chae, Byung-yoon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.11 no.1
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    • pp.269-283
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    • 1998
  • Paranasal sinusitis, especially chronic is one of the most common diseases in the field of otolaryngology. It is similar to Bee Yeun(鼻淵) in oriental medicine. Most cases of sinusitis are due to anatomical abnormalities within ostiomeatal unit or disturbed mucocilliary flow. The ostiomeatal unit is the first place of contact with bacteria and allergens during aspiration, and it can be obstructed easily by minute mucosal swelling due to anatomical narrowness. Therefore the treatment of paranasal sinusitis is not easy and often leads to recurrences in spite of long term treatment or surgical therapy. We studied 83 patients who had visited our hospital with complaints of nasal symptoms; they had been diagnosed as having paranasal sinusitis through an endoscopy or CT scan in another hospital and were diagnosed as the paranasal sinusitis through a PNS series. The results were as follows: 1. Age and sex distribution: The most common occurence was found between 6-10 and 1-5 years old. The Males Were 52($62.7\%$) and Females were 31($37.3\%$). 2. By residence 58 cases lived in apts: 25 lived in houses. 3. The longest duration of disease varied from a lower of 13 to a higher of 36 months in 22 cases and from 7 to 12 months in 21 cases. 4. The most common complication & past history with otolaryngologic or allergic disease were adenoid or tonsil hypertrophy & tonsillectomy and adenoidectomy (21 cases). In decreasing order the others were atopic dematitis, otitis media with effusion and allergic rhinitis. 5. Distribution of paranasal sinus disease was most common in both maxillary sinuses in 52 cases. 12 cases showed a normal PNS X-ray series but these had been diagnosed as paranasal sinusitis with an endoscopy or CT scan in another hospital. 6. Common sinusitis - related symptoms were from highest incidence to lowest nasal obstruction, postnasal drip rhinorrhea, frontal headache, cough with sputum. 7. The most administered of prescription was Gamibangpoongtongsungsan and Sunbangpaedoksan extract. 8. In 26 cases the subjects showed significant improvement symptoms in PNS X-ray series : In 21 case showed partial improvement symptoms.

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Studies on antiplatelet activity of Tabebuia impertiginosa Martius ex DC(Taheebo) (Tabebuia impertiginosa Martius ex DC(Taheebo)의 혈소판 응집 억제활성에 관한 연구)

  • Seo Beom-seok;Go Gwan-Young;Park Young-Hyun;Park Byeoung-Su;Chang Sung-Keun
    • Proceedings of the KAIS Fall Conference
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    • 2004.06a
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    • pp.253-257
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    • 2004
  • Platelet aggregation is a complex phenomenon that probably involves several intracellular biochemical pathways. When activated, platelets change shape, aggregate and release the contents of their intracellular granules. The interactions between platelets and blood vessel walls are important in the development of thrombosis and cardiovascular diseases. When blood vessels are damaged, platelet aggregation occurs rapidly to form haemostatic Plugs or arterial thrombi at the sites of vessel injury or in regions where blood flow is disturbed. These thrombi are the source of thromboembolic complications of atherosclerosis, heart attacks, stroke, and peripheral vascular disease. Therefore, the inhibition of platelet function represents a promising approach for the prevention of thrombosis. Plants constitute a rich source of bioactive chemicals such as phenolics, terpenoids and alkaloids. Plant extracts may be an alternative to currently used medicinal source because they constitute a rich source of bioactive chemicals. This study was performed to investigate the antiplatelet activity of extract of Tabebuia impetiginosa Martius ex DC (Taheebo) and find out which fractions to this activity in rabbit platelet. Taheebo was methanol extracted and solvent fractionated in to five fractions (hexane, chloroform, ethylacetate, butanol and water). And each fractions were investigated inhibitory effects on platelet aggregation induced by various agonists using washed rabbit platelets in vitro.

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Riparian Environment Change and Vegetation Immigration in Sandbar after Sand Mining (골채채취 후 수변환경 변화와 사주 내 식생이입)

  • Kong, Hak-Yang;Kim, Semi;Lee, Jaeyoon;Lee, Jae-An;Cho, Hyungjin
    • Journal of Korean Society on Water Environment
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    • v.32 no.2
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    • pp.135-141
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    • 2016
  • This study investigated changes of hydrology, soil characteristics, riparian vegetation communities, and geomorphology in sandbars before and after sand-mining to determine the effect of sand-mining at upstream of Guemgang and Bochungcheon streams in Korea. Sand-mining events affected the mining area. They supplied organic matters and nutrients during flood. Sediment deposition caused soil texture change and expansion of vegetation area. However, riverbeds were stabilized after the disturbance. According to the analyses of aerial photographs, the vegetation area was significantly expanded in both dam-regulated streams and dam-unregulated streams after sand-mining. Willow shrubs advanced in disturbed area at an average of 10 years after sand-mining. It took willows trees 10.6 years to become dominant communities. Therefore, it took a total of 20.6 years for new riparian forest to form in sandbar after sand-mining. Our results confirmed that stream flow condition were dependent on vegetation recruitment in dam-regulated streams and dam-unregulated streams. For willow recruitment in unregulated streams, calculation of water level below dimensionless bed shear stress is important because low water level variation is a limiting factor of vegetation recruitment.

Computational simulations of transitional flows around turbulence stimulators at low speeds

  • Lee, Sang Bong;Seok, Woochan;Rhee, Shin Hyung
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.13 no.1
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    • pp.236-245
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    • 2021
  • In this study, direct numerical and large eddy simulations of transitional flows around studs were conducted to investigate the effectiveness of turbulence stimulators at very low speeds for the minimum propulsion power condition of four knots. For simplicity, the studs were assumed to be installed on a flat plate, while the wake was observed up to 0.23 m downstream behind the second stud. For applicability to a model ship, we also studied the flow characteristics behind the first and second studs installed on a curved plate, which was designed to describe the geometry of a bulbous bow. A laminar-to-turbulent transition was observed in the wake at ReD ≥ 921 (U≥0.290 m/s), and the wall shear stress at ReD = 1162 (U = 0.366 m/s) in the second wake was similar to that of the fully developed turbulent boundary layer after a laminar-to-turbulent transition in the first wake. At ReD = 581 (U = 0.183 m/s), no turbulence was stimulated in the wake behind the first and second studs on the flat plate, while a cluster of vortical structures was observed in the first wake over the curved plate. However, a cluster of vortical structures was revealed to be generated by the reattachment process of the separated shear layer, which was disturbed by the first stud rather than directly initiated by the first stud. It was quite different from a typical process of transition, which was observed at relatively high ReD that the spanwise scope of the turbulent vortical structures expanded gradually as it went downstream.

Studies on the Fracture Healing in the Alloxan treated Rabbits (Alloxan 투여 가토(家兎)에 대한 골절치유 실험)

  • Kim, Sung-Joon
    • The Korean Journal of Pharmacology
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    • v.7 no.1
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    • pp.53-65
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    • 1971
  • It is well known that diabetes mellitus is associated with metabolic derangements, such as hyper-glycemia, ketosis, glycosuria, and also widespread alterations in the blood vessels, kidneys, eyes, peripheral nerves and heart. It is also recognized that healing of skin wound is delayed in diabetics. In bone, according to Aegerter, osteopenia develops in diabetes mellitus and it is chiefly ascribed to overutilization of protein. Shim claims that total blood flow to the entire skeletal system is approximately 4 to 8 percent of resting cardiac output and blood supply to the skeletal system would be decreased on account of secondary arteriosclerotic changes in the diabetics. An adequate blood supply is an essential factor in the healing process of fracture, and disturbed blood flow, either local or systemic, will invariably delay union of the fragments or the fragments from being fused. As the author has encountered several cases of diabetics in whom healing of fracture was delayed or incomplete, this experimental study was undertaken to elucidate the effects of hyperglycemia and diabetes mellitus on the healing process of fracture. In this experiment adult albino rabbits, weighing about 2 kg. were used and divided into 6 groups. The femur of each animal was fractured surgically, and then the healing process of fracture was periodically checked by radiography at an interval of one week for a period of 6 weeks. Thereafter, all the rabbits were killed to obtain tissue preparation of the femur. The experimental groups were as follows; 1) Control group: Six rabbits sustained a surgical fracture to the femur, without being given any other treatment or drug. 2) Alloxan-treated group: For inducing diabetes, alloxan was given intravenously to 17 rabbits in various dose as follows; to 7 of them 40 mg/kg, to 6 rabbits 80 mg/kg and to 4 rabbits 120 mg/kg of body weight, respectively. 3) Insulin-treated group: Protamine-zinc insulin was injected subcutaneously to each of 6 rabbits in a daily dose of 1 unit per kilogram of body weight. 4) Group treated with insulin after alloxan: Four rabbits were given 80 mg of alloxan once and than 1 unit of insulin per kilogram of body weight daily. Another 5 rabbits were injected 1 unit of insulin per kg of body weight daily following administration of alloxan in a dose of 120 mg/kg. 5) Homotransplantation group: Following intravenous injection of alloxan in a dose of 120 mg/kg, 10 rabbits underwent homotransplantation of a short bone segment to the femur. Five of them were subsequently given 1 unit/kg of insulin daily. 6) Sugar-treated group: six rabbits were fed $15{\sim}20$ gm of sugar daily throughout the period of experiment. The results obtained are summarized as follows; 1. Blood sugar level and damage to the pancreatic islet increased proportionately when alloxan was given to the rabbits in various doses. No appreciable change could be observed in the islets when the blood sugar level was altered by either oral administration of sugar or subcutaneous injection of insulin. 2. Comparing with the control group, healing of fracture was delayed in the alloxan-treated group, while callus formation and periosteal reaction were shown to be more prominent in this group and subsequently, the ultimate osseous tissue formed at the fracture site was significantly smaller in amount and less compact. These findings were more marked as the amount of alloxan increased. 3. Administration of insulin prevented the delay in healing process of fracture in the rabbits with alloxan-induced hyperglycemia. In this case, the course and progression of fracture healing were almost similar to those of control group. 4. Union between the host bone and the fragment transplanted from other rabbit of the same species was more delayed in the group treated with alloxan alone than in the group to which insulin was administered after development of alloxan-induced diabetes. In both groups periosteal new bone developed from the ends of the host bone, above and below the transplanted fragment, and directly fused with failure of periosteal callus to bridge the adjacent ends of the host bone and the transplanted fragment. 5. The healing process of fracture was not inhibited by alteration in blood sugar level when the blood sugar was abnormally increased by excessive sugar intake or lowered by administration of insulin alone. The healing of fracture in these groups progressed similarly as in the control group. In brief summary, it appears that the healing process of fracture would be definitely disturbed in diabetic state brought about by damage to the pancreatic islet. As such an inhibition could be overcome with insulin, it seems that insulin plays an important role in healing of fracture, but alteration in blood sugar level alone does not modify healing process of fracture to significant degree.

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