• The Korean Journal of Physiology and Pharmacology
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• 제19권2호
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• pp.99-104
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• 2015

The aim of this study is to develop a physiologically based pharmacokinetic (PBPK) model in intra-abdominal infected rats, and extrapolate it to human to predict moxifloxacin pharmacokinetics profiles in various tissues in intra-abdominal infected human. 12 male rats with intra- abdominal infections, induced by Escherichia coli, received a single dose of 40 mg/kg body weight of moxifloxacin. Blood plasma was collected at 5, 10, 20, 30, 60, 120, 240, 480, 1440 min after drug injection. A PBPK model was developed in rats and extrapolated to human using GastroPlus software. The predictions were assessed by comparing predictions and observations. In the plasma concentration versus time profile of moxifloxcinin rats, $C_{max}$ was $11.151{\mu}g/mL$ at 5 min after the intravenous injection and $t_{1/2}$ was 2.936 h. Plasma concentration and kinetics in human were predicted and compared with observed datas. Moxifloxacin penetrated and accumulated with high concentrations in redmarrow, lung, skin, heart, liver, kidney, spleen, muscle tissues in human with intra-abdominal infection. The predicted tissue to plasma concentration ratios in abdominal viscera were between 1.1 and 2.2. When rat plasma concentrations were known, extrapolation of a PBPK model was a method to predict drug pharmacokinetics and penetration in human. Moxifloxacin has a good penetration into liver, kidney, spleen, as well as other tissues in intra-abdominal infected human. Close monitoring are necessary when using moxifloxacin due to its high concentration distribution. This pathological model extrapolation may provide reference to the PK/PD study of antibacterial agents.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.247-250
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• 1996

In this paper, we have examined the impedance characteristics of a tipper link of human being in a positioning motion. Firstly, we have shown the characteristics of the human arm using a bilinear model. From the bilinear model, we have observed that both the driving torque of the forearm and the visco-elasticity of the elbow joint can be controlled by muscles, respectively. Then, we have defined several indexes to show the impedance characteristics. Using the proposed indexes, we have examined the impedance characteristics in the positioning operation. As a result, we can not observe the difference of the impedance characteristics, even if the ease of the positioning motion is varied.

• 대한의용생체공학회:의공학회지
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• 제21권2호
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• pp.189-201
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• 2000

Mechanical factors in the human body are considered to play a dominant role in low back problems. Various spinal structures. including muscles, act in unison to resist the external load. An estimation of the muscle forces in this structure requires a knowledge of the orientation, location and area of cross-section of the muscles to complete the formulation of a truly three-dimensional mathematical model of the spine. The geometric parameters which are calculated were the line of action, the centroid and physiologic area of cross-section of each muscle as a function of the spinal level. This geometric data were obtained from CT scans of 11 subjects participating in this study.

• 한국가시화정보학회지
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• 제16권2호
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• pp.31-37
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• 2018

Ischemic mitral regurgitation (IMR) is the primary mitral valve (MV) pathology in the aftermath of myocardial infarction as a consequence of regional left ventricular (LV) remodeling. We investigated the effect of asymmetric papillary muscle (PM) displacement and annular dilation on IMR development. Virtual MV modeling was performed to create a normal human MV. Asymmetric PM displacement, asymmetric annular dilation, and the combination of these two pathologic characteristics were modeled. Dynamic finite element evaluation of MV function was performed across the complete cardiac cycle for the normal and three different IMR MV models. While the normal MV demonstrated complete leaflet coaptation, each pathologic MV model clearly revealed deteriorated leaflet coaptation and abnormal stress distributions. The pathologic MV model having both asymmetric PM displacement and annular dilation showed the worst leaflet malcoaptation. Simulation-based biomechanical evaluation of post-ischemic LV remodeling provides an excellent tool to better understand the pathophysiologic mechanism of IMR development.

• 대한기계학회논문집A
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• 제41권8호
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• pp.691-701
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• 2017

본 연구에서는 스미스 머신을 이용한 스쿼트 운동에 대한 가상 테스트 프레임웍을 제안하고 구현하였다. 이를 위하여 인체 및 제품의 통합 모델을 개발하고, 실험 데이터를 바탕으로 자세의 변화에 따른 새로운 동작을 생성하는 알고리즘을 개발한 후, 가상의 조건에서 동작을 생성하여 인체의 관절에 걸리는 토크와 근육에 걸리는 힘을 시뮬레이션 하는 전체 시스템을 개발하였다. 이 시스템을 검증하기 위하여 동작 수집과 더불어 EMG와 지면반력에 대한 데이터를 수집하여 시뮬레이션 결과가 실제와 잘 맞는지 확인하였다. 이 시스템을 확장시켜 사용한다면 다양한 조건에서 운동하였을 때 신체 근육과 관절에 어떤 영향을 끼치는 지 시뮬레이션 해봄으로써 적절한 운동 프로그램을 효과적으로 개발할 수 있을 것으로 기대된다.

• 대한기계학회논문집A
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• 제41권1호
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• pp.1-6
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• 2017

헬멧을 착용한 병사의 비관통 피탄 충격은 총탄이 헬멧을 관통하지 않더라도 인체에 치명적인 상해를 유발한다. 이로 인한 인체 상해 해석을 위한 연구들이 이뤄져 왔으나 주로 두부의 손상에 초점을 맞춘 해석 모델이 개발되어 왔다. 비관통 피탄 충격에 의한 경추 및 경추부 관련 근육의 손상은 인체에 치명적인 상해를 입히지 않더라도 병사의 생존성에 상당한 영향을 미친다. 따라서 경추 및 경추부 근육을 포함한 모델 개발이 필요하다. 본 연구에서는 기존에 연구된 두부 모델과 근육 모델이 적용된 경추부 모델을 활용하여 인체의 상해해석을 수행하였다. 정량적 상해예측을 위해 응력, 변형률 및 HIC를 비교하였다. 경추부가 포함된 모델의 해석결과는 두부 모델만 고려된 해석결과보다 상해 정도를 작게 예측하였다. 모델의 신뢰성 확보를 위하여 두부 상해 해석 결과를 타 문헌과 비교하였다.

• 전기학회논문지
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• 제56권11호
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• pp.2040-2050
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• 2007

In this study, we present a novel method for estimating the information of MU(motor unit) which is the basic element of human muscle by using surface EMG. Some of the method developed in this field could only estimate the numbers of MU that is activated. However, in our study the MU-simulator based on the line source model was designed to estimate the MU information including the numbers of MU and muscle fiber, conduction velocity, MU diameter, fiber diameter, and end plate position. The SMUAP(single motor unit action potential) detector was designed and CMAP(compound muscle action potential) by electrical stimulus was recorded. With these data, the MU-simulator can estimate the MU information by varying muscle paramater settings through MSE(mean square error) method. Our results shows that the proposed method can be comparable with the method of anatomical studies. Moreover, our system can be utilized to build a tool for diagnosis and treatment assessment of neuromuscular patients.

• Molecules and Cells
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• 제41권3호
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• pp.198-206
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• 2018

Aortic dissection (AD) is a catastrophic disease with high mortality and morbidity, characterized with fragmentation of elastin and loss of smooth muscle cells. Although AD has been largely attributable to polymorphisms defect in the elastin-coding gene, tropoelastin (TE), other undermined factors also appear to play roles in AD onset. Here, we investigated the effects of post-transcriptional control of TE by microRNAs (miRNAs) on elastin levels in aortic smooth muscle cells (ASMC). We found that miR-144-3p is a miRNA that targets TE mRNA in both human and mouse. Bioinformatics analyses and dual luciferase reporter assay showed that miR-144-3p inhibited protein translation of TE, through binding to the 3'-UTR of the TE mRNA. Interestingly, higher miR-144-3p levels and lower TE were detected in the ASMC obtained from AD patients, compared to those from non-AD controls. In a mouse model for human AD, infusion of adeno-associated viruses (serotype 6) carrying antisense for miR-144-3p (asmiR-144-3p) under CAG promoter significantly reduced the incidence and severity of AD, seemingly through enhancement of TE levels in ASMC. Thus, our data suggest an essential role of miR-144-3p on the pathogenesis of AD.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1679-1682
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• 2008

Pulsatile Extracorporeal Membrane Oxygenation(ECMO) can mitigate the heart load and raise the patient's blood perfusion. But If the ECMO pulsate the blood flow during the systolic period, It can burden to the patient's heart. To avoid the heart injury, we have to consider the relation between output of ECMO, hemodynamic states and heart movement. To raise the efficacy of the pulsatile ECMO, we investigated the coronary perfusion, cardiac muscle tension and hemodynamic states during the ECMO perfusion by using the mathematical model of human blood circulatory system and ECMO. The outflow data of the pulsatile ECMO(T-PLS, Bioheartkorea, Korea) was obtained in vitro experiments. According to the phase and pumping rate of the ECMO, the heart's load and coronary perfusion could be adjusted to the proper levels. The results of the human- ECMO lumped parameter model showed that the synchronizing operation of the pulsatile ECLS can be helpful at stabilizing the patient's hemodynamic states.

• 한국CDE학회논문집
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• 제17권6호
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• pp.443-455
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• 2012

The configuration of a musculoskeletal (MS) system is closely related to the individual motions of the human body. Many researches have been focused on evaluating the associations between the MS configuration and the individual motion using patient-specific MS models, but it still remains a challenging issue to accurately predict the motion by differed configurations of the MS system. The main objective of this paper is to predict the changes of a patient-specific gait by altering the geometric parameters of the hip joint using function-based morphing method (FBM). FBM is suitable for motion analysis since this method provide a robust way to morph a MS model while preserving the biomechanical functions of the bones. Computed-muscle control technique is used to calculate the muscle excitations to reproduce the targeted motion within a digital MS model without the motion-captured data. We applied this approach to a patient who has an abnormal gait pattern. Results showed that the femoral neck length and the angle significantly affect to the motion especially for the hip abduction angle during gait, and that this approach is suitable for gait prediction.