• Title/Summary/Keyword: Bypass function

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Effect of Cardiopulmonary Bypass on Platelet (체외순환이 혈소판에 미치는 영향)

  • Choe, Jun-Yeong;Seo, Gyeong-Pil
    • Journal of Chest Surgery
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    • v.21 no.1
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    • pp.26-35
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    • 1988
  • The effect of cardiopulmonary bypass on platelet count, platelet function, and bleeding time was studied in 60 patients. Platelet count was significantly reduced during and after cardiopulmonary bypass. Platelet function also had a reduced aggregation response to adenosine diphosphate. Bleeding time was prolonged to over 30 minutes during cardiopulmonary bypass and not returned to normal level until postbypass 1 hour. The amount of postoperative bleeding was proportional to the degree of decrease in platelet count and function, degree of decrease in platelet count and function. There was no significant correlation between duration of cardiopulmonary bypass and platelet count, platelet function, bleeding time, or amount of postoperative bleeding. Patients with cyanotic congenital heart disease showed a larger amount of postoperative bleeding than patients with acyanotic congenital heart disease [P<0.01], and this difference was due to the fact that platelet function was more significantly affected by cardiopulmonary bypass in cyanotic group. Patients using membrane oxygenator showed a less amount of postoperative bleeding than patients using bubble oxygenator [p<0.005] reflecting better preservation of platelet count and function by membrane oxygenator.

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Partial Left Heart Bypass for Perioperative Left Ventricular Failure [A Report of 2 Clinical Cases] (개심술시 병발한 좌심실 기능부전에 대한 Partial Left Heart Bypass 치험)

  • 이종국
    • Journal of Chest Surgery
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    • v.18 no.2
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    • pp.193-204
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    • 1985
  • During the period from February to March, 1984, we employed a partial left heart bypass [left atrium to ascending aorta] in 2 patients who could not weaned from cardiopulmonary bypass with inotropic agents and cardiac pacing after coronary bypass surgery. These two patients showed significant improvement in ventricular function 18 to 47 hours after inserting the left heart bypass and were able to wean from the left heart bypass under using inotropic agents. Two patients died of multiple organ failures 11 days and 15 days postoperatively. These results indicate that early institution of left heart bypass in ventricular failure patients after open heart surgery can provide satisfactory long-term result.

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Influences of Prolonged Extracorporeal Circulation on Organ Function in Dogs (장시간의 체외순환이 생체에 미치는 영향)

  • 김의윤
    • Journal of Chest Surgery
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    • v.7 no.1
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    • pp.73-78
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    • 1974
  • Influences on organ function were studied in animals during prolonged extracorporeal circulation with a bubble type of oxygenator. More than six hours of total cardiopulmonary bypass was performed under mild hypothermia by means of an extracorporeal circulation system in five dogs. Obtained results were summarized as follows. 1. The renal function was not so impaired seriously until four hours of extracorporeal circulation. However, there was more serious impairment of renal function in this study when extracorporeal circulation was carried out for a period of five hours or more. 2. There was gradual hepatic damage during extracorporeal circulation and the damage was more significant after bypass for a period of five to six hours. 3. There was a significant decrease in serum K during bypass, irrespective of the pump oxygenator prime with a high K solution. The reason for this is complex and due to many factors, however, it was evidently related to serum glucose levels during extracorporal circulation.

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Clinical Effect of Albumin Addition to the Prime solution in Cardiopulmonary Bypass (체외순환시 산화기 충전액에 첨가된 알부민의 임상적 효과)

  • Lee, Hyeong-Gyo;Yu, Se-Yeong
    • Journal of Chest Surgery
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    • v.23 no.6
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    • pp.1152-1157
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    • 1990
  • Colloid solution is commonly used to increase the oncotic pressures of priming solutions used in the cardiopulmonary bypass circuit. To study the effectiveness of this practice, we retrospectively evaluated 24 patients undergoing cardiac operations to receive isoelectric solution plus 50 gm of albumin[group A], isoelectric solution plus 25 gm of albumin[group B] and isoelectric solution without albumin[group C] as the prime solution for the bypass circuit. Various clinical parameters related to the perioperative fluid balance, cardiopulmonary function, and renal function were studied. There were no differences between the three groups with regard to postoperative clinical parameter of cardiopulmonary, liver function and renal function. But at the previous report by Cho et al. [38], there was a significant difference between groups with regard to hematologic property, especially in crenated red blood cells. These hematologic events did not affect the clinical outcome but thorough evaluations are needed in order to prove the clinical effect of crenated red blood cell. We conclude that there is no clinically detectable advantage for the routinely supplementing of albumin to the priming solution of bypass circuit in cardiac operations. Whether this practice can be of value in selected cases needs to be further studied.

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Experimental Study on Characteristics of Two-Phase Flow through a Bypass Orifice Expansion Device

  • Choi, Jong-Min;Kim, Yong-Chan
    • International Journal of Air-Conditioning and Refrigeration
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    • v.9 no.1
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    • pp.11-19
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    • 2001
  • To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which was a short tube haying a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them. and it would enhance the seasonal energy efficiency ratio of an inverter heat pump system, Based on experimental data, a semi-empirical flow model was developed to predict mass flow rate through bypass orifices. The maximum difference between measured data and model`s prediction was within $\pm$5%.

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Experimental study on characteristics of two-phase flow through a bypass-orifice expansion device (바이패스 오리피스 팽창장치의 유동 특성에 관한 실험적 연구)

  • Choi, J.M.;Kim, Y.C.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.11 no.1
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    • pp.109-116
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    • 1999
  • To establish optimum cycle of the inverter-driven heat pump with a variation of frequency, the bypass orifice, which is a short tube having a bypass hole in the middle, was designed and tested. Flow characteristics of the bypass orifice were measured as a function of orifice geometry and operating conditions. Flow trends with respect to frequency were compared with those of short tube orifices and capillary tubes. Generally, the bypass orifice showed the best flow trends among them, that will enhance the seasonal energy efficiency ratio of an inverter heat pump system. Based on experimental data, the semi-empirical flow model was developed to predict mass flow rate through bypass orifices. The maximum difference between measured data and model's prediction was within ${\pm}5%$.

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Site-specific Disruption of Glyoxylate Bypass and Its Effect in Lysine-producing Corynebacterium lactofermentum Strain

  • Kim, Youn-Hee;Lee, Heung-Shick
    • Journal of Microbiology and Biotechnology
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    • v.6 no.5
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    • pp.315-320
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    • 1996
  • The role of glyoxylate bypass in a lysine-producing Corynebacterium lactofermentum strain was analyzed. Unlike the wild type, the strain expressed enzymes of glyoxylate bypass during growth in the fermentation broth containing glucose as the carbon source. To evaluate the importance of glyoxylate bypass in the strain, we disrupted chromosomal aceA by using a cloned fragment of the gene. Site-specific disruption of aceA which codes for the isocitrate lyase, the first enzyme of the bypass, was confirmed by Southern blot analysis. The aceA mutant strain completely lost isocitrate lyase activity and ability to grow in a minimal medium containing acetate as the sole carbon source. The mutant strain was similar to its parental strain in growth characteristics and produced comparable amounts of lysine in shake flasks containing glucose as the carbon source. The amount of oxaloacetate accumulated in the fermentation medium was similar for both strains, suggesting that expression of glyoxylate bypass does not necessarily lead to the increase in intracellular oxaloacetate. These data clearly demonstrate that glyoxylate bypass does not function as one of the routes of carbon supply for lysine production in the strain. It appears that the leakiness of the glyoxylate bypass in the strain might be the result of a secondary mutation which arose during previous strain development by random mutagenesis.

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The Characteristic of the Performance of the Bypass Diode with Composition Change of the String in Si-PV Module (결정질 PV 모듈의 string 구성에 따른 바이패스 다이오드 동작 특성)

  • Ji, Yang-Geun;Kong, Ji-Hyun;Kang, Gi-Hwan;Yu, Gwon-Jong;Ahn, Hyung-Gun;Han, Deuk-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2212-2217
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    • 2010
  • Previous studies have been focused on the voltage of Bypass diode and Isc(Short Circuit Current) of the influenced solar cell. The Bypass diode starts working when it gets the reverse applied voltage. Previous studies have only concentrated on Isc of the influenced solar cell and Imp of PV module to explain the bypassing performance. PV module is usually working together with inverter having MPPT(Maximum Power Point Tracking) function for best performance. bypassing point is regulated by MPPT function of inverter. In this paper, simulation results of Bypass diode in PV module have been analyzed to represent the relationship of the bypassing point with the composition of PV module. From the results, the more cells are connected with each string, the earlier bypassing performance happens under the fixed number of strings. As diode groups increase or irradiation decreases, the bypassing performance starts fast.

The effect of cardiopumonary bypass on the concentrations of thyroid hormone (체외순환이 갑상선호르몬 농도에 미치는 영향에 관한 연구)

  • Kim, Gyu-Man;Jeon, Sang-Hyeop;Kim, Jong-Won
    • Journal of Chest Surgery
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    • v.27 no.7
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    • pp.571-575
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    • 1994
  • The hemodynamic effects of thyroid hormone are well established, and this hormone affects myocardial contractility, heart rate, and myocardial oxygen consumption. But the role of cardiopulmonary bypass on the thyroid function is not yet fully understood. We have studied twelve patients [male and female patients were equal in number] who were performed open heart surgery under cardiopulmonary bypass. The results are followed. 1] The serum level of T3 began to fall after cardiopulmonary bypass and sustained significantly till 24 hours after operation[p<0.05] 2] The concentrations of T4, Free T4, and TSH were slightly decreased after cardiopulmonary bypass but was maintained within normal range. 3] This above findings are similar to the "sick sinus syndrome" that is seen in severely ill patient. 4] We can propose that T3 would be effective in postoperative low cardiac output syndrome. syndrome.

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A Study of Attacks to Bypass CFI on Android Application Environment (안드로이드 애플리케이션 환경에서 CFI 우회 공격기법 연구)

  • Lee, Ju-yeop;Choi, Hyoung-kee
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.30 no.5
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    • pp.881-893
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    • 2020
  • CFI(Control Flow Integrity) is a mitigation mechanism that protects programs by verifying control flows. IFCC(Indirect Function Call Checks) and SCS(Shadow Call Stack), CFI supported by LLVM Clang compiler, were introduced to protect applications in Android. IFCC protects function calls and SCS protects function returns. In this paper, we propose attacks to bypass CFI on the application environment with IFCC and SCS. Even if IFCC and SCS were applied to user applications, it was confirmed that there were many code segments not protected by IFCC and SCS in the application memory. We execute code in CFI unprotected segments to construct 1) bypassing IFCC to call a protected function, 2) modulating return address via SCS bypass. We identify code segments not protected by IFCC and SCS in Android10 QP1A. 191005.007.A3. We also implement proof-of-concept exploits to demonstrate that modulation of control flow is possible in an environment where IFCC and SCS are applied.