• Journal of Pharmaceutical Investigation
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• 제39권5호
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• pp.373-379
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• 2009

This study was conducted to develop a pharmacokinetic-pharmacodynamic (PK/PD) model of a direct thrombin inhibitor, argatroban to predict the concentration-effect profiles in rats. Argatroban was i.v. injected to rats at 0. 2, 0.8 and 3.2 mg/kg doses (n = 4-5 per dose), and plasma drug levels were determined by a validated LC/MS/MS assay. The pharmacokinetics of argatroban was linear over the i.v. dose range studied. The thrombin time (TT) and the activated partial thromboplastin time (aPTT) were measured in rat plasma and they were found to linearly increase with increasing the dose. A 2-compartment pharmacokinetic model linked with an indirect response pharmacodynamic model was successfully utilized to evaluate the drug concentration-response relationship.

• 한국화재소방학회논문지
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• 제23권6호
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• pp.111-115
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• 2009

아세톤 LIF와 Rayleigh 산란법 등 두 가지 레이저 측정 기법을 이용하여 Re수가 1,000 미만의 부력제트 노즐근처에서의 공기 유입을 실험적으로 조사하였다. 아세톤 LIF 실험결과 전체적인 혼합기구는 경계면에서의 불안정성에 의한 거대와구조로 판단되고, Re 수가 커질수록 유입되는 시점이 상류로 이동하며 그 양 또한 증가되었다. 또한 Rayleigh 산란법 결과는 상류에서도 혼합이 제트의 내부까지 이루어지고, 노즐에서 분사방향으로 진행할수록 주위공기의 유입이 제트 내부로 진행되고 있음을 알 수 있다. 이 실험결과로서 기존 등온기체모델에서 제트의 주위공기 유입을 고려하여야 한다는 사실을 입증할 수 있다. 또한, 이상적 플룸식에서 복사열손실을 0.35로 고려하였을 경우에 기존의 연기량 및 온도 예측과 근사한 결과를 얻을 수 있으며, 주위공기 유입효과를 고려하여 보다 간단하면서 정확한 등온기체 모델링 방법을 얻을 수 있다.

• 대한의용생체공학회:의공학회지
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• 제24권4호
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• pp.329-337
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• 2003

선천적 혹은 후천적인 이유로 인하여 인체 특정 부위의 정맥과 동맥이 서로 관통하여 동맥계의 혈류가 말초 혈관계를 우회하여 정맥계로 흐르게 되는 동정맥루는 인체 심혈관계의 혈류 역학적 거동에 큰 영향을 미치게 된다. 본 연구에서는 lumped parameter 모델을 기반으로 하는 수치 해석 방법을 사용하여 우측 하지에 위치한 급성 동정맥루가 전체 심혈관계에 미치는 영향을 해석적으로 고찰하였다. 이를 위하여 동정맥루가 포함된 인체 심혈관계를 전기 회로 상사계로 구성하였으며. 부위별 혈압과 관련된 상미분 연립 방정식을 4차의 Runge-Kutta방법으로 풀어서 시간에 따른 혈류 역학적 변수들을 구하였다 이때 급성 동정맥루의 생성에 따른 혈류 역학적 보상작용을 분석하기 위하여 arterial baroreflex 제어계를 모델에 포함하였다.

• 대한의용생체공학회:의공학회지
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• 제3권1호
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• pp.9-16
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• 1982

Removal of urea and vitamin B12 was simulated using two pool models with closed loop dialysis, open loop dialysis, and hemodiafiltrations with predilution and postdilulion. It was found that urea removal was limited by dialyzer clearance, however B12 removal was limited both by the resistance between ECF and ICF and by dialyzer clearance. Open loop dialysis was better than closed loop dialysis in terms of dialysate requirement and removal efficiency. Residual renal function plays an important role in removing vitamin B12. Dialysis frequency more than twice/wide does not have great effect on removal efficiency, but has the effect of reducing the difference between maximum and minimum cancentrations during dialysis period.

• Journal of international Conference on Electrical Machines and Systems
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• 제3권1호
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• pp.27-31
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• 2014

Magnetic fields (MF) generated both on board the vehicle and along the guideway provide levitation and propulsion forces. High speed maglev trains adopt electromagnet or superconducting magnet to realize levitation and propulsion functions. However, stray fields existing in passenger compartment and regions surrounding the vehicle and guideway have effect on passengers and environment. To investigate stray magnetic field effect, model of Transrapid and MLX are studied.

• 한국임상약학회지
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• 제26권4호
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• pp.312-317
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• 2016

Objective: Midazolam is mainly metabolized by cytochrome P450 (CYP) 3A. Inhibition or induction of CYP3A can affect the pharmacological activity of midazolam. The aims of this study were to develop a population pharmacokinetic (PK) model and evaluate the effect of CYP3A-mediated interactions among ketoconazole, rifampicin, and midazolam. Methods: Three-treatment, three-period, crossover study was conducted in 24 healthy male subjects. Each subject received 1 mg midazolam (control), 1 mg midazolam after pretreatment with 400 mg ketoconazole once daily for 4 days (CYP3A inhibition phase), and 2.5 mg midazolam after pretreatment with 600 mg rifampicin once daily for 10 days (CYP3A induction phase). The population PK analysis was performed using a nonlinear mixed effect model ($NONMEM^{(R)}$ 7.2) based on plasma midazolam concentrations. The PK model was developed, and the first-order conditional estimation with interaction was applied for the model run. A three-compartment model with first-order elimination described the PK. The influence of ketoconazole and rifampicin, CYP3A5 genotype, and demographic characteristics on PK parameters was examined. Goodness-of-fit (GOF) diagnostics and visual predictive checks, as well as bootstrap were used to evaluate the adequacy of the model fit and predictions. Results: Twenty-four subjects contributed to 900 midazolam concentrations. The final parameter estimates (% relative standard error, RSE) were as follows; clearance (CL), 31.8 L/h (6.0%); inter-compartmental clearance (Q) 2, 36.4 L/h (9.7%); Q3, 7.37 L/h (12.0%), volume of distribution (V) 1, 70.7 L (3.6%), V2, 32.9 L (8.8%); and V3, 44.4 L (6.7%). The midazolam CL decreased and increased to 32.5 and 199.9% in the inhibition and induction phases, respectively, compared to that in control phase. Conclusion: A PK model for midazolam co-treatment with ketoconazole and rifampicin was developed using data of healthy volunteers, and the subject's CYP3A status influenced the midazolam PK parameters. Therefore, a population PK model with enzyme-mediated drug interactions may be useful for quantitatively predicting PK alterations.

• 한국어병학회지
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• 제23권1호
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• pp.57-67
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• 2010

퀴놀론계 항균제인 nalidixic acid(OA), piromidic acid(PA), oxolinic acid(OA)를 사육수온($13{\pm}1.5^{\circ}C$, $23{\pm}1.5^{\circ}C$)에 따라서 넙치(평균체중 700 g)에 60 mg/kg의 농도로 1회 경구 투여한 다음, 경시적인 혈청내 잔류농도를 분석하였다. 수온이 $23{\pm}1.5^{\circ}C$의 경우, 투여 후 NA는 10시간째 ($11.55{\mu}g/m\ell$), PA는 24시간째($3.79{\mu}g/m\ell$), OA는 30시간째($1.12{\mu}g/m\ell$)에 각각 최대혈중농도에 도달하였다. 수온이 $13{\pm}1.5^{\circ}C$의 경우, 투여 후 NA는 10시간째($6.36{\mu}g/m\ell$), PA는 15시간째($1.4{\mu}g/m\ell$), OA는 30시간째($1.01{\mu}g/m\ell$)에 각각 최대혈중농도에 도달하였다. NA와 PA의 넙치 혈중내 흡수정도는 수온 $13{\pm}1.5^{\circ}C$보다 수온 $23{\pm}1.5^{\circ}C$에서 매우 높게 나타났으며, NA의 넙치 혈중내 소실정도는 수온 $13{\pm}1.5^{\circ}C$보다 수온 $23{\pm}1.5^{\circ}C$에서 두드러지게 빨랐다. 한편 OA의 넙치 혈중내 흡수 및 소실정도는 사육수온에 크게 영향을 받지 않는 것으로 나타났다. NA 및 PA는 one-compartment model, OA는 two-compartment model로 해석하여 WinNonlin program을 이용, 약물동태학적 매개변수(parameter)를 조사하였다. 수온이 $23{\pm}1.5^{\circ}C$의 경우, 혈장농도-시간곡선하 면적(AUC)은 NA, PA, OA가 각각 258.26, 248.12 및 $138.20{\mu}g{\cdot}h/m\ell$, 혈중최고농도의 도달시간($T_{max}$)은 10.67, 21.15 및 23.95 h, 혈중최고농도($C_{max}$)는 8.91, 3.09 및 $1.06{\mu}g/m\ell$로 계산되었다. 수온이 $13{\pm}1.5^{\circ}C$의 경우, AUC는 NA, PA, OA가 각각 341.45, 103.89 및 $159.10{\mu}g{\cdot}h/m\ell$, 혈중최고농도의 도달시간은 7.72, 12.89 및 28.03 h, 혈중최고농도는 6.23, 1.22 및 $1.02{\mu}g/m\ell$로 계산되었다.

• 수산해양기술연구
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• 제52권2호
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• pp.88-95
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• 2016

Most grid sorting has been used to sort out flatfish in shrimp fisheries, while double grid systems have been tested to separate smaller shrimp. The escape of juvenile red seabream through separating panels made with steel grids or large mesh tested for masking effects in a two-species system. Fish behavior was observed in a circulating water tank. The escape rate was 20% greater with the separating codends than with the normal codend in the single-species experiments. The rates in the two-species experiments were 30% or 20% greater than the single-species rates for the normal or separating codends, respectively. The seabream retention rates in the grid separator codend decreased as rockfish retention increased, possibly due to a threat effect. Conversely, the retention rate of both species increased concurrently in the net separator, possibly due to a masking effect. The escape rates of juvenile red seabream varied by compartment in the mesh separating codend. These results suggest that grid separating codends can be used in the field as towed fishing gear to reduce juvenile catch.

• Journal of Theoretical and Applied Mechanics
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• 제3권1호
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• pp.34-44
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• 2002

Theoretical analysis Is carried out to identify the modal coupling effect between some particular acoustic modes of a vehicle compartment cavity and vibration modes of body panels like side doors, roof or floor. A simplified panel-cavity coupled model is investigated on the coupled resonance frequencies, modes and frequency response characteristics. Through parametric study, It Is possible to explain how the acoustic response of a coupled system will be determined by the vibration and acoustic property of the individual panel and cavity system. Full coupled system shows some interesting features different from those of the semi-coupled system In frequency, mode and acoustic response.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.813-818
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• 1989

A two compartmented autoclave reactor for the polymerization of low density polyethylene is analyzed with respect to the effects of heat transfer and operation variables. Each compartment being considered as a completely mixed cell, two CSTRs model is proposed. The system shows various multiplicity features of steady state and periodic oscillatory motions. Heat removal efficiency and initiator supplement appear to have significant effect on the conversion of monomer with the temperature properly maintained, which should be taken into account in the reactor design.