재생 불량성 빈혈 환자에서 심장초음파를 이용한만성 철 과부하에 의한 심근의 변화

정우백,홍은주,윤호중,박철수,오용석,정욱성,김재형,최규보,홍순조,이종욱 대한심장학회 2006 Korean Circulation Journal Vol.36 No.6

The Expression of Cardiac Ankyrin Repeat Protein in an Animal Model of Adriamycin-Induced Cardiomyopathy

정우백,윤호중,최윤석,박철수,오용석,정욱성,김재형,이정화 대한심장학회 2008 Korean Circulation Journal Vol.38 No.9

Background and Objectives: Cardiac ankyrin repeat protein (CARP) is an embryonic nuclear protein, and its expression is increased under conditions of pressure or volume overload and also in the failing heart. Adriamycin is a cardiotoxic chemotherapeutic agent, and it suppresses the expression of CARP. We compared the expressions of CARP in the myocardium of normotensive rats and spontaneously hypertensive rats (SHRs) that suffered with adriamycin-induced cardiomyopathy. Materials and Methods: 36 Wistar-Kyoto rats (WKYs) and 36 SHRs were divided into the adriamycin-administered and saline-administered groups. Adriamycin (2.5 mg/kg) and saline were injected intraperitoneally twice a week for 3 weeks. All the animals were sacrificed 3 weeks after the last injection. Immunohistochemical staining was performed on the left ventricles with using synthesized polyclonal CARP antibody. The positively stained areas were measured by using an image analysis program, and the CARP volume fractions (CaVF) were calculated. Results: CARP was diffusely expressed in the cytoplasm of the myocytes in all the groups. The number of CARP expressing cells was increased in the SHRs. The CaVFs was 5.96±5.11% in the WKYs and it was 9.04±6.26% in the SHRs (p=0.014). The CaVF was 2.26±4.74% in the adriamycinadministered WKYs and it was 1.24±4.32% in the adriamycin-administered SHRs (p=0.32). The adriamycinadministered WKYs and SHRs showed significantly decreased CARP expressions, as compared to the saline-administered groups (p<0.001 and p<0.001, respectively). Conclusion: These results suggest that CARP is closely related to the pathogenesis of adriamycin-induced cardiomyopathy and it probably plays a pivotal role for the adriamycin cardiac toxicity observed in hypertensive rats. Background and Objectives: Cardiac ankyrin repeat protein (CARP) is an embryonic nuclear protein, and its expression is increased under conditions of pressure or volume overload and also in the failing heart. Adriamycin is a cardiotoxic chemotherapeutic agent, and it suppresses the expression of CARP. We compared the expressions of CARP in the myocardium of normotensive rats and spontaneously hypertensive rats (SHRs) that suffered with adriamycin-induced cardiomyopathy. Materials and Methods: 36 Wistar-Kyoto rats (WKYs) and 36 SHRs were divided into the adriamycin-administered and saline-administered groups. Adriamycin (2.5 mg/kg) and saline were injected intraperitoneally twice a week for 3 weeks. All the animals were sacrificed 3 weeks after the last injection. Immunohistochemical staining was performed on the left ventricles with using synthesized polyclonal CARP antibody. The positively stained areas were measured by using an image analysis program, and the CARP volume fractions (CaVF) were calculated. Results: CARP was diffusely expressed in the cytoplasm of the myocytes in all the groups. The number of CARP expressing cells was increased in the SHRs. The CaVFs was 5.96±5.11% in the WKYs and it was 9.04±6.26% in the SHRs (p=0.014). The CaVF was 2.26±4.74% in the adriamycinadministered WKYs and it was 1.24±4.32% in the adriamycin-administered SHRs (p=0.32). The adriamycinadministered WKYs and SHRs showed significantly decreased CARP expressions, as compared to the saline-administered groups (p<0.001 and p<0.001, respectively). Conclusion: These results suggest that CARP is closely related to the pathogenesis of adriamycin-induced cardiomyopathy and it probably plays a pivotal role for the adriamycin cardiac toxicity observed in hypertensive rats.

Early Cardiac Function Monitoring for Detection of Subclinical Doxorubicin Cardiotoxicity in Young Adult Patients with Breast Cancer

정우백,이정은,진정연,최윤석,박찬석,박우찬,송병주,윤호중 한국유방암학회 2013 Journal of breast cancer Vol.16 No.2

Purpose: As doxorubicin cardiotoxicity is considered irreversible, early detection of cardiotoxicity and prevention of overt heart failure is essential. Although there are monitoring guidelines for cardiotoxicity, optimal timing for early detection of subclinical doxorubicin cardiotoxicity is still obscure. The purpose of this study is to determine optimal timing of cardiac monitoring and risk factors for early detection of doxorubicin cardiotoxicity in young adult patients with breast cancer. Methods: Medical records of 1,013 breast cancer patients diagnosed from January 2009 to December 2010 is being reviewed and analyzed. Properly monitored patients are defined as patients who underwent transthoracic echocardiography before and after the chemotherapy. The definition of subclinical cardiotoxicity (SC) either decreases left ventricular ejection fraction (LVEF) more than 10% or the LVEF declines under 55% from baseline without heart failure symptoms. Results: Twenty-nine out of 174 (16.7%) properly monitored young adult female patients (mean age, 52±10 years old) developed SC. The mean interval of cardiac evaluation of SC group was 5.5±3.0 months. Among the risk factors, the history of coronary artery disease, cumulative dose of doxorubicin ≥300 mg/m2 and use of trastuzumab after doxorubicin therapy were associated with development of SC. At cumulative dose of doxorubicin 244.5 mg/m2, SC can be predicted (sensitivity, 71.4%; specificity, 70.9%; area under the curve, 0.741; 95% confidence interval, 0.608-0.874; p=0.001). Conclusion: In young adult patients with breast cancer, SC was common at cumulative dose of doxorubicin <300 mg/m2 and early performance of cardiac monitoring before reaching the conventional critical dose of doxorubicin might be a proper strategy for early detection of SC.

호흡곤란의 감별진단

정우백 대한내과학회 2021 대한내과학회 추계학술대회 Vol.2021 No.2

급성 골수성 백혈병 환자에서 발생한 국소성 신장 아스페르길루스증 1예

정우백,이동건,최영기,박선희,최수미,김희제,신완식 대한내과학회 2004 대한내과학회지 Vol.67 No.5S

다중 MFC에 의한 IPMSM 드라이브의 MTPA 제어

백정우(Jeong-Woo Baek),고재섭(Jae-Sub Ko),최정식(Jung-Sik Choi),강성준(Sung-Jun Kang),장미금(Mi-Geum Jang),문주희(Ju-Hui Mun),정동화(Dong-Hwa Chung) 한국조명·전기설비학회 2010 한국조명·전기설비학회 학술대회논문집 Vol.2010 No.5월

This paper proposes maximum torque control of IPMSM drive using multi model reference adaptive fuzzy controller(MFC) and artificial neural network(ANN). This control method is applicable over the entire speed range which considered the limits of the inverter's current and voltage rated value. For each control mode, a condition that determines the optimal d-axis current i<SUB>d</SUB> for maximum torque operation is derived. This paper considers the design and implementation of novel technique of high performance speed control for IPMSM using multi-MFC and ANN controller. The hybrid combination of neural network and fuzzy control will produce a powerful representation flexibility and numerical processing capability. Also, this paper proposes speed and current control of IPMSM using MFC and estimation of speed using ANN controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The proposed control algorithm is applied to IPMSM drive system controlled MFC and ANN controller, the operating characteristics controlled by maximum torque control are examined in detail. Also, this paper proposes the analysis results to verify the effectiveness of the MFC and ANN controller.

결구상추 균핵병 발생과 Bacillus mojavensis Pro-EB 15 균주에 의한 생물학적 방제

백정우,김현주,박종영,이광열,강준호,이진우,정순재,문병주 한국생명과학회 2003 한국생명과학회 심포지움 Vol.40 No.-

Characteristics of Germanium n+/p junctions formed by phosphorus diffusion from on indium-gallium-phosphide layer

백정우,심재우,박진홍 한국물리학회 2015 Current Applied Physics Vol.15 No.7

Although numerous studies have been previously reported for the formation of Ge pen junctions, there is still a lack of research on Ge junctions formed by solid-phase diffusion doping, which typically uses the diffusion phenomenon of phosphorus (P) atoms from InGaP for the fabrication of a Ge n+/p subcell in a III eV multi-junction cell. Here, we investigate the characteristics of Ge n+/p junctions achieved by the InGaP-based diffusion technique at 450-650 ℃ with SIMS, ECV, and J-V analyses. In addition, through a multiple error function fitting method, diffusivity, peak position, and activation energy values are accurately estimated from raw In/Ga/P/Ge SIMS profiles. The extracted activation energy values for In/Ga/ P atoms are much lower than previously reported, indicating that a faster diffusion phenomenon occurs during the simultaneous diffusion of In/Ga/P into Ge. A non-annealed InGaP-deposited junction shows Ohmic behavior with a high current density because of leakage currents by many interfacial point defects. Although numerous studies have been previously reported for the formation of Ge pen junctions, there is still a lack of research on Ge junctions formed by solid-phase diffusion doping, which typically uses the diffusion phenomenon of phosphorus (P) atoms from InGaP for the fabrication of a Ge n+/p subcell in a III eV multi-junction cell. Here, we investigate the characteristics of Ge n+/p junctions achieved by the InGaP-based diffusion technique at 450-650 ℃ with SIMS, ECV, and J-V analyses. In addition, through a multiple error function fitting method, diffusivity, peak position, and activation energy values are accurately estimated from raw In/Ga/P/Ge SIMS profiles. The extracted activation energy values for In/Ga/ P atoms are much lower than previously reported, indicating that a faster diffusion phenomenon occurs during the simultaneous diffusion of In/Ga/P into Ge. A non-annealed InGaP-deposited junction shows Ohmic behavior with a high current density because of leakage currents by many interfacial point defects. After a 550 ℃ anneal, the current density is reduced by 3-4 orders of magnitude and a small on/ off-current ratio is obtained. Compared to this 550 ℃ annealed junction, a current density increases ~10 times in the 650 ℃ sample due to an increased n-type carrier concentration.

A production–inventory system with a Markovian service queue and lost sales

백정우,문승기 한국통계학회 2016 Journal of the Korean Statistical Society Vol.45 No.1

We study an (s, S) production–inventory system with an attached Markovian service queue. A production facility gradually replenishes items in the inventory based on the (s, S) scheme, and the production process is assumed to be a Poisson process. In addition to the production–inventory system, c servers process customers that arrive in the system according to the Poisson process. The service times are assumed to be independent and identically distributed exponential random variables. The customers leave the system with exactly one item at the service completion epochs. If an item is unavailable, the customers cannot be served and must wait in the system. During this out-of-stock period, all newly arriving customers are lost. A regenerative process is used to analyze the proposed model. We show that the queue size and inventory level processes are independent in steadystate, and we derive an explicit stationary joint probability in product form. Probabilistic interpretations are presented for the inventory process. Finally, using mean performance measures, we develop cost models and show numerical examples.

Markov-modulated fluid flow model with server maintenance period

백정우,이호우,안수한 한국통계학회 2020 Journal of the Korean Statistical Society Vol.49 No.2

We consider a Markov-modulated fluid flow model with server maintenance period. As soon as the fluid level reaches zero, the server begins a maintenance period of a random length. During the maintenance period, fluid arrives from outside depending on the state of the background Markov process and the level increases either vertically or linearly. This model can be applied to various real-world systems such as inventory systems and production systems. We first derive the distribution of the fluid level and the mean performance measures. Then, we present some numerical examples to show the effect of the maintenance time.