• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권5호
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• pp.1588-1603
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• 2014

In space diversity combining, conventional methods such as maximal ratio combining (MRC), equal gain combining (EGC) and selection combining (SC) are commonly used to improve the output signal-to-noise ratio (SNR) provided that the channel is perfectly estimated at the receiver. However, in practice, channel estimation is often imperfect and this indeed deteriorates the system performance. In this paper, diversity combining techniques based on two evolutionary algorithms, namely genetic algorithm (GA) and particle swarm optimization (PSO) are proposed and compared. Numerical results indicate that the proposed methods outperform the conventional MRC, EGC and SC methods when the channel estimation is imperfect while it shows similar performance as that of MRC when the channel is perfectly estimated.

• 한국정보통신학회논문지
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• 제8권5호
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• pp.970-976
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• 2004

본 논문에서는 MRC(Maximal Ratio Combing) 결합 기법을 사용한 RAKE 수신기에서 채널 추정 알고리즘에 따른 성능을 분석한다. 채널 추정 알고리즘에는 WMSA(Weighted Multi-Slot Averaging), 동일 이득 채널 추정 (Equal Cain Estimation ; ECE), 심볼 단위 채널 추정(Symbol-to-Symbol Estimation ; SSE)의 세 가지가 있는데 상업용 시뮬레이션 틀인 HP사의 ADS를 이용하여 비동기 방식 IMT-2000시스템(3GPP)을 대상으로 성능을 분석한다. 성능 분석을 위해서 본 논문은 Jakes 페이딩 채널 모델을 사용한다. 모의실험 결과를 통하여, 저속 도플러(3Km/h)일 때 WMSA 알고리즘이 다른 알고리즘 성능보다 더 좋음을 알 수 있다. 그러나 고속 도플러(120Km/h)일 때, 간단한 구조를 갖는 ECE 알고리즘이 보다 더 유용함을 알 수 있다.

• 한국컴퓨터정보학회논문지
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• 제11권5호
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• pp.195-201
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• 2006

MC-CDMA의 전체 시스템 대역폭은 부대역으로 분할되며, 각 부대역은 직접시권스확산을 사용하고 각 부대역 신호는 부캐리어 주파수를 사용하여 전송한다. 본 논문에서는 주파수 선택적 나까카미-m 페인팅 채널에서 동이득 합성법과 최대비 합성법을 사용한 MC-CDMA시스템 성능을 분석한다. 본 논문에서 제안된 시스템은 데이터 스트림을 직렬에서 병렬로 변환하여, 각 병렬 데이터 스트림을 MC-CDMA시스템에 사용한다. 데이터 스트림은 송신기에서 칩 레벨과 심볼 프락션 레벨을 확산시킨다. 본 논문에서는 동 이득 합성과 최대비 합성 두가지 다이버시티 합성법을 비교분석하였다. 동이득 합성법 보다 최대비 합성법을 사용한 시스템 성능이 우월하였다.

• 대한본초학회지
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• 제32권1호
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• pp.25-31
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• 2017

Objectives : Mori Radicis Cortex (MRC), the root epidermis of Morus alba L., has been traditionally used to treat lung-related diseases in Korean Medicine. The common of MRC is Mulberry bark Morus bark, and it's pharmaceutical properties and taste are known as sweet and cold, and it promotes urination and reduce edema by reducing heat from the lungs and soothe asthma. In the present study, anti-apoptotic mechanism of MRC in middle cerebral artery occlusion (MCAO) model in mice. Methods : Two-hundred grams of MRC was extracted with methanol at room temperature for 5 days, and this was repeated one time. After filtration, the methanol was removed using vacuum evaporator, then stored at $-20^{\circ}C$ until use. C57BL/6 male mice were housed in an environment with controlled humidity, temperature, and light cycle. In order to determine beneficial effects of MRC on ischemia induced brain damage, infarct volume, neurological deficit scores, activities of several apoptosis-related proteins such as caspase-8, -9, Bcl-xL in MCAO-induced brains of mice were analyzed. Mice in MRC-treated groups were orally administered 30, 100, or 300 mg/kg of body weight for three consecutive days before commencing the MCAO procedure. Results : Pre-treatment of MRC significantly reduced infarct volume in MCAO subjected mice applied with 300 mg/kg of MRC methanol extract, and MRC effectively inhibited Bcl-xL reduction and caspase-9 activation caused by MCAO-induced brain damage. Conclusions : MRC showed neuro-protective effects by regulating apoptosis-related protein signals, and it can be a potential candidate for the therapy of ischemia-induced brain damage.

• 조명전기설비학회논문지
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• 제12권3호
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• pp.114-123
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• 1998

The multi-resonant converter(MRC) minimizes a parasitic oscillation by using the resonant tank circuit absorbed parasitic reactances existing in a converter circuit. So it si possible that the converter operated at a high frequency has a high efficiency because the losses are reduced. Such a MHz high frequency applications provide a high power density [W/inch3] of the converter. But the resonant voltage stress across a switch of the resonant tank circuit is 4~5 times a input voltage. This h호 voltage stress increases the conduction loss because of on-resistance of a MOSFET with higher rating. Thus, in this paper we proposed the alternated multi-resonant converter (AT MRC) differ from the clamp mode multi-resonant converter and applicated it to the forward MRC. The AT forward MRC can reduce the voltage stress to 2~3 times a input voltage by using two series input capacitor. The control circuit is simple because tow resonant switches are driven directly by the output pulse of the voltage controled oscillator. This circuit type is verified through the experimental converter with 48V input voltage, 5V/50W output voltage/power and PSpice simulation. the measured maximum voltage stress is 170V of 2.9 times the input voltage and the maximum efficiency of 81.66% is measured.

• Restorative Dentistry and Endodontics
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• 제17권2호
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• pp.263-286
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• 1992

This study was performed to evaluate and compare the cytotoxic effects of five root canal sealers to several different cell lines. Five root canal sealers were AH-26, N2, Sealapex, Tubliseal, and Vitapex. Each sealers were mixed according to the manufacturer's instructions, and culture media were added to each sealers immediately after mixing (the immediate group) and after three days (the third day group) and seven days (the seventh day group) respectively. And every sealer solutions were diluted to 1:1, 1:2, 1:3 and 1:4. Three different permanent cell lines (HEp-2, McCoy, MRC-S) and human gingival fibroblasts and mononuclear cells were challenged by each sealer solution and the cytopathic effects were evaluated using MTT-ELISA, MTT-microscopy, and lactate dehydrogenase (LD) activity. The results were as follows: 1. In HEp-2 and MRC-5 cells, Vitapex was the least cytotoxic sealers. 2. AH-26 showed mild cytotoxic effects to HEp-2, gingival fibroblast and mononuclear cells. 3. N2 was the most toxic sealer to gingival fibroblast and it showed relatively strong cytotoxicity to HEp-2, McCoy and MRC-S cells. 4. Tubliseal showed strong cytotoxic effects to HEp-2, McCoy, MRC-S, and mononuclear cells. 5. Sealapex showed strong cytotoxic effect to HEp-2, McCoy, and gingival fibroblasts.

• Tuberculosis and Respiratory Diseases
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• 제67권6호
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• pp.528-535
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• 2009

Background: Dust clouds blown by the wind from the arid deserts of Mongolia and Northeast China are known as Asian dust storms. Ambient particulate matter with a diameter <10 ${\mu}m$ ($PM_{10}$) is associated with the exacerbation of respiratory diseases and increased mortality of heart and lung disease patients. The fibrotic effects of $PM_{10}$ of Asian dust to pulmonary fibroblast cells are unknown. This study examined the production of reactive oxygen species (ROS), TGF-${\beta}$, NF-${\kappa}B$, PDGF-$\alpha$ and Fibronectin in fibroblasts exposed to Asian dust particles. Methods: Air samples were collected using a high volume air sampler (Sibata model HV500F) with an air flow of 500 L/min for at least 6 hours. The MRC-5 cells were exposed to 0, 50 and 100 ${\mu}g/mL$ of $PM_{10}$ for 24 hours. ROS was detected by measuring the level of oxidized DCF using FACS. TGF-$\beta$, NF-${\kappa}B$, PDGF-$\alpha$ and fibronectin were detected by western blotting. Results: There was no increase in the ROS, TGF-$\beta$ and PDGF-$\alpha$ levels in the MRC-5 cells exposed to $PM_{10}$. The NF-${\kappa}B$ level was higher in the MRC-5 cells exposed to 50 and 100 ${\mu}g/mL$ of $PM_{10}$ for 24 hours. The fibronectin level in the MRC-5 cells after 24 hours incubation with 50 ${\mu}g/mL$ $PM_{10}$ was significantly higher than the control group ($PM_{10}$ 50 ${\mu}g/mL$ 113.27${\pm}$8.65 of control, p=0.005). Conclusion: $PM_{10}$ from Asian dust increases the activation of NF-${\kappa}B$ and fibronectin expression in MRC-5 fibroblast cells.

• 전자공학회논문지S
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• 제34S권1호
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• pp.145-153
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• 1997

This paper proposes a constant frequency controlled forward zero voltage switching multi resonant converter (ZVS-MRC) which operates with a fixed duty ratio. The proposed converter is obtained from a conventional forward ZVS-MRC by placing a saturable core in parallel with the secondary side of the transformer. Experimental results are presented for a proposed converter which operates at 1.5MHz switching frequency with an output power of 50W (5V/10A). The merits of the proposed converter include ; 1) reduced voltage stress to the main switch compared with the conventional counterpart, 2) ease on designing the magnetic components including EMI and output filter, and 3) simple control scheme.

• 한국식품위생안전성학회지
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• 제8권1호
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• pp.37-53
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• 1993

옥수수에 자연 발생하는 F. monliforme MRC 826을 옥수수에 배양하여 배양물에 존재하는 fumonisin $B_{1}$을 정성검사 한 후, 배양물질의 독성 및 발암성을 aflatoxin $B_{1}$과 비교하여 보았다. 독성 시험은 3주령의 Sprague-Dawley(SD) 암컷 랫드 10마리를 각 군당 5마리씩 2개 군으로 나누어 제1군은 시험 군으로 배양물질을 분말사료와 1 : 1로 혼합하여 1주간 급여하였고, 제 2군은 대조군으로 분말사료만을 급여하면서 실험하였다. 시험군은 급여 3~4일경부터 침울해 보였으며, 랫드 1마리당 1주간 평균 사료 섭취량은 24 g이었고, 평균 체중은 18 g 감소하였다. 부검 시 신장의 피막박리가 곤란하였고 조직 검사 결과 간장의 공포변성에 신장 세뇨관 상피세포의 괴사등의 관찰되었다. 발암성 검사 6주령의 SD 수컷 랫드 70마리를 사용하여 중기 발암성 검색법인 diethylnitrosamine-partial hepatectomy (DEN-PH) 모델로 시험하였다. 시험군은 각 군당 14마리씩 총 5개군을 두었으며 실험 0일 때 DEN을 복상내로 투여하였고, 2주후에 제 1군(양성대조군)은 aflatoxin $B_{1}$을 2ppm 농도로 첨가한 사료를, 제4군 옥수수를 5% 농도로 첨가한 사료를, 제 5군은 옥수를 2.5% 농도로 첨가한 사료를 각각 6주간 급여하였다. 실험 3주간에 간 부분 절제술을 시술하였고, 8주간 체중변화, 사료섭취량 음수량을 측정한 후 부검하여 간장은 glutathione S-transferase placental form (GST-P) 면역조직화학적 염색을 실시하였고, 뇌, 뇌하수체, 융선, 폐, 부신, 신장, 심장, 비장, 정낭선, 고환 및 간장 등은 H&E 염색을 하여 병변을 관찰하였다. GST-P 염색결과 5% 배양물질 투여군은 aflatoxin $B_{1}$투여군과 유사하게 GST-P 양성병소의 발현율이 대조군에 비하여 유의성 있는 증가를 보였다. 5% 배양물질 투여군 및 2.5% 배양물질 투여군은 옥수수 투여군에 비하여 증체율의 저하가 관찰되었고, 5% 배양물질 투여군에서 간, 신장, 고환 및 정낭선등의 체중에 대한 상대중량비, 혈액요소질소와 평균 적혈구 혈색소량 등은 옥수수 투여군에 비하여 유의성 있는 변화가 관찰되었다. 이상의 결과들을 종합해 볼 때 F. monliforme MRC 826 배양물질은 랫드의 간과 신장에 독성을 나타내었고, aflatoxin $B_{1}$과 마찬가지로 간암 촉진효과가 있는 것으로 판단되었다.

• 한국자기공명학회논문지
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• 제21권1호
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• pp.31-43
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• 2017

Together with radiotherapy, chemotherapy using cytotoxic agents is one of the most common therapies in cancer. Metabolic changes in cancer cells are drawing much attention recently, but the metabolic alterations by anticancer agents have not been much studied. Here, we investigated the effects of commonly used cytotoxic agents on lung normal cell MRC5 and lung cancer cell A549. We employed cis-plastin, doxorubicin, and 5-Fluorouracil and compared their effects on the viability and metabolism of the normal and cancer cell lines. We first established the concentration of the cytotoxic reagents that give differences in the viabilities of normal and cancer cell lines. In those conditions, the viability of A549 decreased significantly, whereas that of MRC5 remained unchanged. To study the metabolic alterations implicated in the viability differences, we obtained the metabolic profiles using $^1H$-NMR spectrometry. The $^1H$-NMR data showed that the metabolic changes of A549 cells are more remarkable than that of MRC5 cells and the effect of 5-FU on the A549 cells is the most distinct compared to other treatments. Heat map analysis showed that metabolic alterations under treatment of cytotoxic agents are totally different between normal and cancer cells. Multivariate analysis and weighted correlation network analysis (WGCNA) revealed a distinctive metabolite signature and hub metabolites. Two different analysis tools revealed that the changes of cell metabolism in response to cytotoxic agents were highly correlated with the Warburg effect and Reductive lipogenesis, two pathways having important effects on the cell survival. Taken together, our study addressed the correlation between the viability and metabolic profiles of MRC5 and A549 cells upon the treatment of cytotoxic anticancer agents.