• Journal of Biomedical Engineering Research
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• v.27 no.2
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• pp.59-63
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• 2006

Magnetocardiogram (MCG) topography is a useful diagnostic technique that employs multi-channel magnetocardiograms. Measurement of artifact-free MCG signals is essenctial to obtain MCG topography or map for a diagnosis of human heart. Principal component analysis (PCA) combined with an artificial neural network (ANN) is proposed to remove a pulse-type artifact in the MCG signals. The algorithm is composed of a PCA module which decomposes the obtained signal into its principal components, followed by an ANN module for the classification of the components automatically. In the experiments with volunteer subjects, 97% of the decisions that were made by the ANN were identical to those by the human experts. Using the proposed technique, the MCG topography was successfully obtained without the artifact.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.834-838
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• 2003

Background: Deairing from the heart after open heart surgery(cardiopulmonary bypass) is a very important procedure. Artificial arteriovenous fistula was used to remove air, and the efficiency was evaluated by transesophageal echocardiography. Material and Method: Just before termination of cardiopulmonary bypass, a standard pressure transducer line is connected between the stopcocks of the connections in the arterial and venous circuits, creating a small controlled arteriovenous fistula between the arterial and venous cannulas. The degree of intracardiac air and air removal time were evaluated either by transesophageal echocardiography or direct vision of pressure transducer line. Result: By simple procedure, cardiopulmonary time was shortened and air clearing can be confirmed using echocardiography in a few minutes. Conclusion: Creation of arteriovenous fistula using small connecting line between aortic and venous cannula is a very simple and effective method of deairing and preventing of air embolism after open heart surgery.

• Journal of Biomedical Engineering Research
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• v.18 no.2
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• pp.147-156
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• 1997

Various prosthetic heart valves have been developed and used clinically, but they have problems, such as thrombogenecity, hemoltsis, high cost and low durability. New types of trileaflet polymer heart valves have been developed in order to use them as inlet and outlet valves in a ventricular assist device. The aim of this study is to determine the hydrodynamic effectiveness of the newly designed trileaflet polymer valves and their feasibility for temporary use in the blood pumps. Trileaflet polymer valves are made of polyurethane, because of its good blood compatibility, high tonsil strength and good resistance to fatigue. An in vitro experimental investigation was perf'ormed in order to ev91ua1e hydrodynamic performance of the trileaflet polymer valves having different design and fabrication tech- niques. The St. Jude Medical valve (SJMV) and floating-type monoleaflet polymer valve (MLPV) were also tested The pressure drop across the valve, leakage volume, and the flow patterns mere investigated for valves. The result of comparative tests showed that the trileaflet polymer valves had a better hydrodynamic performance than the others. TPV which has two stable membrane shape showed the lowest back flow. The pressure hops of TPVs were lower than that of MLPV, but slightly higher than SJMV. The hydrodynamic performance of valves under the pulastile flow showed the similar results as steady flow. The velocity profiles and turbulent intensities were measured at the distal sites of valves using a hot-film anemometer. Central flow was maintained in trileaflet polymer valves, and the maximum turbulent intensities were lower in TPVs comparing to MLPV.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.609-619
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• 1999

심장은 생명의 가장 중요한 장기 중 하나이며, 이 중요성은 인공심장의 연구를 불러일으켰다. 본 고에서는 전세계적으로 연구되는 인공 심장 제어의 방법론, 추세 그리고 현 상황을 비교 분석하였다. 인공 심장 개발에 있어서 중요한 연구 분야 중 하나인 인공 심장 제어는 자연 심장의 역할을 최대한 모방하여야 하는데 현실적으로 각종 생리적 제어 인자를 얻기에는 센서 기술의 한계가 있다. 따라서 인공 심장을 위한 많은 제어 변수가 연구되었으나, 단지 몇 가지만 실제로 적용되는 상태이다. 본고에서는 왜 다른 요인들이 제외되었으며 무엇이 현재 제어 방식의 선택 기준으로 고려되었는지를 설명한다. 이것을 설명하기 위하여 인공 심장의 제어에 앞서서 자연 심장의 제어를 짧게 설명하고, 5개의 대표적인 인공 심장 제어 연구 조직을 선정하여 소개와 정리를 하였다.

• Journal of Biomedical Engineering Research
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• v.23 no.2
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• pp.131-137
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• 2002

The remote monitoring system including hemodynamic information and pump status of the implanted animal could be helpful during the in vivo experiment or clinical trial for an artificial heart Implantation. In order to monitor the course of the in vivo experiment continuously and anywhere, web-based remote monitoring system was developed, which can monitor pressures(AoP, LAP, RAP, PAP) and flow information as well as the pump operating conditions. The system consists of data sending, storing viewer part. The data sending part was constructed using component object model and the viewer part was constructed using the Java applet. In addition, the dialog box was introduced to communicate earth other instantly and the alarming function was also introduced when the hemodynamic values were out of the desired ranges. The developed remote monitoring system was applied during the in vivo experiment of the BVAD (Bi-ventricular Assist Device) implantation for 1 month and showed designed work without failure.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.296-304
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• 2001

배경: 이번 연구의 목적은 체내이식형 양심실 보조장치의 개발을 위한 안전하고 간편한 동물실험 모델을 확립하는 것이며 이동작동형 완전 인공심장의 양심실 보조장치로의 사용 가능성을 알아보는 것이다. 대상 및 방법: 7마리의 Corridale 양을 대상으로 실험하였다. 5번째 늑간극을 통하여 좌측 개흉술을 시행하고 좌측 유출로 캐뉼라는 하행 대동맥에 Dacron graft을 사용하여 연결하였고 유입로 캐뉼라는 좌심방에 삽입하였다. 우측 유출로 캐뉼라는 하행 대동맥과 같은 방법으로 주폐동맥에 연결하였으며 유입로 캐뉼라는 혜동맥을 하방으로 젖혀 우심방이를 노출시킨 다음 우심방이에 삽입하였다. 4마리에 있어서는 양심실 보조장치를 전복막강(preperitoneal space)에 위치시켰으며 2마리에 촤측흉강 내에, 1마리에서는 외부에 위치시켰다. aPTT는 수술전 aPTT의 2∼2.5배로 맞추어 주었다 결과: 수술중 또는 수술직후 사망한 경우는 없었으며 7마리 모두 인공호흡기 이탈이 가능하였고 스스로 기립하고 음식물 섭취도 가능하였다. 1마리는 술후 2일째 혈전 색전증 및 인공호흡기 작동 잘못으로 사망하였으며 2마리의 겨우는 술후 2일째 각각 양심실 보조장치의 작동 잘못 및 호흡부전으로 사망하였고, 3마리의 경우는 술후 4일째 혈전색전증으로 인한 급성신부전 및 호흡부전 등으로 사망하였다. 1마리에 있어서는 28일간 생존하였으며 양심실 보조장치의 구동 장치에 연결된 라인의 마로로 인해 양심실 보조장치의 작동이 정지되었으나 바로 양심실 보조장치를 제거하고 살릴 수 있었다. 모든 경우에 있는 캐뉼라를 삽입하고 양심실 보조장치를 작동시키는데 큰 어려움이 없었다. 7마리 중 4마리에서 혈전이 발견되었으며 특히 판막을 연결한 부위에 혈전생성이 많았다. 그러나 캐뉼라에는 혈전생성이 없었다. 결론: 양에 있어서 좌측 개흉술 및 전복막강 공간에 양심실 보조장치를 위치시키는 이번 동물실험 모델은 체내 이식형 양심실 보조장치 개발을 위한 좋은 동물실험 모델이라고 생각된다. 또한 디동 작동기형 완전 인공심장의 혈전생성을 억제할수 있는 방법들의 연구개발이 지속된다면 장기간의 체내 이식형 양심실 보조장치로 사용할 수 있을 것으로 생각된다.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.257-269
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• 2021

The purpose of this study is to collect biosignal data in a non-invasive and non-restrictive manner using a BCG (Ballistocardiogram) sensor, and utilize artificial intelligence machine learning algorithms in ICT and high-performance computing environments. And it is to present and study a method for developing and validating a data-based blood glucose prediction model. In the blood glucose level prediction model, the input nodes in the MLP architecture are data of heart rate, respiration rate, stroke volume, heart rate variability, SDNN, RMSSD, PNN50, age, and gender, and the hidden layer 7 were used. As a result of the experiment, the average MSE, MAE, and RMSE values of the learning data tested 5 times were 0.5226, 0.6328, and 0.7692, respectively, and the average values of the validation data were 0.5408, 0.6776, and 0.7968, respectively, and the coefficient of determination (R²) was 0.9997. If research to standardize a model for predicting blood sugar levels based on data and to verify data set collection and prediction accuracy continues, it is expected that it can be used for non-invasive blood sugar level management.

• Journal of Biomedical Engineering Research
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• v.45 no.3
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• pp.109-117
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• 2024

We developed a device that integrates digital otoscope and stethoscope for telemedicine. The integrated device was utilized for the collection of tympanic membrane images and cardiac auscultation data. Data accumulated on the platform server can support real-time diagnosis of heart and eardrum diseases using artificial intelligence. Public data from Kaggle were used for deep learning. After comparing with various deep learning models, the MobileNetV2 model showed superior performance in analyzing tympanic membrane data, and the VGG16 model excelled in analyzing cardiac data. The classification algorithm achieved an accuracy of 89.9% for eardrums data and 100% for heart sound data. These results demonstrate the possibility of diagnosing diseases without the limitations of time and space by using this platform.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.3
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• pp.106-120
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• 2010

Objectives: Sanjointang has been clinically used much for treating sleeplessness. However, the effects of Sanjointang in artificial sleep deprivation situations are not known. The purpose of this study is to evaluate the heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, and -dp/dt / +dp/dt ratio which are related to the hemodynamic functions of the heart by using sleep-deprived Sparague-Dawley rats, in order to clarify the impact of Sanjointang on hemodynamic functions of the heart of sleep deprived rats. Methods: Eighteen hearts were removed from the male Sparague-Dawley rats weighting about 180g were perfused by the Langendorff technique with modified 37 Krebs-Henseleit's buffer solution at a constant perfusion pressure (60mmHg). They were randomly assigned to one of the following three groups, 1) Normal group (those which did not have sleep deprivation and received normal saline administration), 2) Control group (sleep deprived and normal saline administered), 3) Sample group (sleep deprived and Sanjointang was administered). Control and sample groups rats were deprived 96 hours of sleep by using the modified multiple platform technique. Heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, -dp/dt / +dp/dt ratio were evaluated at baseline after the administration of either normal saline or Sanjointang. Results: The heart rate and -dp/dt / +dp/dt ratio was significantly decreased in rats with 96 hours of sleep deprived significantly decreased. The change in the heart rate after administering Sanjointang did not show any significant difference. The left ventricular systolic pressure of the removed heart significantly decreased due to Sanjointang administration, while the left ventricular diastolic pressure significantly increased (p<0.05). The +dp/dt maximum and -dp/dt maximum both significantly decreased in the removed heart after administering Sanjointang. (p<0.05). There was no significant difference observed in the -dp/dt / +dp/dt ratio after administering Sanjointang. Conclusions: According to the results above, sleep deprivation significantly decreases heart rate and -dp/dt / +dp/dt ratio. This is considered as a result of exhaustion due to accumulation of fatigue. Meanwhile, Sanjointang reduced left ventricular systolic pressure and raised left ventricular diastolic pressure, and relieved the contractility and relaxation of the myocardium. Consequently, this reduces the burden of the heart and creates a relatively stabilized heart condition similar to a sleeping condition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.628-636
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• 2020

Streptococcosis in the olive flounder Paralichthys olivaceus can be caused by Streptococcus parauberis. We compared three routes of administration for experimental injections of the S. parauberis 19FBSPa0003 strain in the olive flounder. Pathological changes were observed during the experimental infection. Inflammation of the serous membrane in the liver, intestine, spleen and heart was the major pathological change found in the infected olive flounder. No mortality was observed in fish that received intraperitoneal (IP) injection at less than 1×10⁴ colony-forming unit (CFU)/fish. The lethal dose 50 for olive flounder, given an intravenous (IV) injection, was 7.94×10⁴ CFU/fish. Fish with a higher concentration of IV injected S. parauberis (1×10⁸ CFU/fish) died within a maximum of two days. However, serious necrosis and bacterial proliferation in ellipsoidal cells of the spleen and heart tissues were found in moribund or dead fish, 1-2 days after IV injection. Similar histopathological signs were observed in olive flounder inoculated by subcutaneous (SC) infected and naturally infected. In addition, SC was also strongly associated with bacteria concentration and cumulative mortality rate. Based on these results, SC is the recommended method for artificial infection by S. parauberis in the olive flounder.