• 대한기계학회논문집B
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• 제35권11호
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• pp.1205-1211
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• 2011

본 논문은 말기 심질환 환자의 생존율과 치료효과를 증대시키기 위한 심실보조장치용 심박조율기의 개발에 대한 내용이다. 심실보조장치만을 이식 받은 환자는 부정맥이 발생할 가능성을 항상 갖고 있으며 심박조율기를 동시에 적용함으로써 혈류의 체순환량을 유지하고 부정맥으로 인한 장기의 손상을 예방한다. 심박조율기의 전극과 도선은 심실보조장치의 도관을 이용하여 제작되었으며, 전극은 심실보조장치의 도관이 삽관되는 좌심실의 심첨부에 도관과 함께 이식된다. 심박조율기는 0 bpm에서부터 191.4 bpm까지 자극 빈도를 조절할 수 있으며, 60 bpm의 빈도로 자극이 가하여 질 때 0.25 J 의 에너지가 심장으로 인가된다. 심실보조장치용 심박조율기의 성능과 안정성을 검증하기 위하여 돼지를 이용한 동물실험을 수행하였다. 실험동물의 심장에 86.4 bpm, 100.2 bpm, 126.6 bpm의 자극을 순차적으로 가하였고 ECG 및 대동맥혈압의 변화 대동맥 혈류를 관찰하였다.

• 한국식품위생안전성학회지
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• 제27권4호
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• pp.406-414
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• 2012

본 연구에서는 fucoidan이 macrophage의 활성과 항암효과를 확인하기 위하여 수행되었다. Fucoidan을 Raw 264.7 세포에 처리한 후 MTT assay로 측정한 결과 고농도 $100{\mu}g/mL$까지 세포독성은 없었으며, NO 및 TNF-${\alpha}$의 분비를 농도 유의적으로 증가시켰다. 또한 AGS 위암 세포 성장저해효과를 확인하기 위하여 MTT assay를 하였고 그 결과 농도와 시간 의존적으로 암 세포 성장이 유의적으로 감소하였다. Apoptosis로 인해 암 세포 성장이 감소하였는지 확인하기 위하여 DAPI 염색을 한 결과 apoptotic body와 세포질 응축이 시간 의존적으로 증가하는 것을 확인하였다. 또한 fucoidan은 미토콘드리아의 투과율을 향상시키며 미토콘드리아에서 방출되는 cytochrome c의 발현을 증가시켰다. Western blotting의 결과 시간 의존적으로 anti-apoptotic 분자인 Bcl-2와 XIAP 발현 감소와 반대로 pro-apoptotic 분자인 Bax 발현이 증가하였다. Cleaved-caspase-9의 발현이 증가하였으며 Akt의 인산화는 시간 의존적으로 감소하였다. Caspase 억제제인 z-VAD-FMK 처리 시 Bax, caspase-9의 발현을 감소시켜 apoptosis 유도를 억제하였으며 이러한 결과는 caspase가 apoptosis 유도에 중요한 역할을 하는 것으로 나타낸다. 본 실험의 AGS 위암 세포주에서 대조군에 비하여 fucoidan 처리군에서 면역세포 활성 및 AGS 위암 세포주에서 caspase 활성을 통해 apoptosis를 유도하는 것으로 사료된다.

• Journal of Ginseng Research
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• 제45권2호
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• pp.295-304
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• 2021

Background: Acute promyelocytic leukemia (APL) is a hematopoietic malignancy driven by promyelocytic leukemia-retinoic acid receptor A (PML-RARA) fusion gene. The therapeutic drugs currently used to treat APL have adverse effects. 20(S)-ginsenoside Rh2 (GRh2) is an anticancer medicine with high effectiveness and low toxicity. However, the underlying anticancer mechanisms of GRh2-induced PML-RARA degradation and apoptosis in human APL cell line (NB4 cells) remain unclear. Methods: Apoptosis-related indicators and PML-RARA expression were determined to investigate the effect of GRh2 on NB4 cells. Z-VAD-FMK, LY294002, and C 87, as inhibitors of caspase, and the phosphatidylinositol 3-kinase (PI3K) and tumor necrosis factor-α (TNF-α) pathways were used to clarify the relationship between GRh2-induced apoptosis and PML-RARA degradation. Results: GRh2 dose- and time-dependently decreased NB4 cell viability. GRh2-induced apoptosis, cell cycle arrest, and caspase3, caspase8, and caspase9 activation in NB4 cells after a 12-hour treatment. GRh2-induced apoptosis in NB4 cells was accompanied by massive production of reactive oxygen species, mitochondrial damage and upregulated Bax/Bcl-2 expression. GRh2 also induced PML/PML-RARA degradation, PML nuclear bodies formation, and activation of the downstream p53 pathway in NB4 cells. Z-VAD-FMK inhibited caspase activation and significantly reversed GRh2-induced apoptosis and PML-RARA degradation. GRh2 also upregulated TNF-α expression and inhibited Akt phosphorylation. LY294002, an inhibitor of the PI3K pathway, enhanced the antitumor effects of GRh2, and C 87, an inhibitor of the TNF-α pathway, reversed NB4 cell viability, and GRh2-mediated apoptosis in a caspase-8-dependent manner. Conclusion: GRh2 induced caspase-dependent PML-RARA degradation and apoptosis in NB4 cells via the Akt/Bax/caspase9 and TNF-α/caspase8 pathways.

• 융합신호처리학회논문지
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• 제7권3호
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• pp.116-121
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• 2006

본 논문에서는 다양한 잡음환경에서의 실시간 적응화 기법을 적용하기 위한 선결 과제로 다차원 음성 특정 벡터를 저차원으로 축소하는 방법을 제안한다. 제안된 방법은 특징 벡터를 확률 우도 값으로 매핑시켜 비선형적으로 축소하는 방법으로 음성 / 비음성의 분류는 우도비 검증 (Likelihood Ratio Test; LRT) 을 이용하여 분류하였다. 실험 결과 고차원 특징 벡터를 이용하여 분류한 결과와 대등하게 분류됨을 확인할 수 있었다. 그리고, 제안된 방법에 의해 검출된 음성 데이터를 이용한 음성인식 실험에서도 10차 MFCC(Mel-Frequency Cepstral Coefficient)를 사용하여 분류한 경우와 대등한 인식률을 보여주었다.

• IMMUNE NETWORK
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• 제5권2호
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• pp.99-104
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• 2005

Background: Malignant gliomas are the most common primary tumors in the central nervous system. Methods: We investigated the combined effect of PG490 and LPS on the induction of the apoptotic pathway in human astroglioma cells. Results: Treatment of U87 cells with combination of 50nM of PG490 and $50{\mu}g/ml$ of LPS resulted in increased internucleosomal DNA fragmentation, cleavage of PLC-${\gamma}1$, and downregulation of cIAP1 and XIAP. The combination of LPS and PG490 treatment-induced apoptosis is mediated through the activation of caspase, which is inhibited by the caspase inhibitor, z-VAD-fmk. Also, release of cytochrome c was found in PG490 and LPS-cotreated U87 cell. Conclusion: Taken together, combination of PG490 and LPS appears to be a potent inducer of apoptosis in astrogliaoma cells, and might have some benefit in the treatment of glioma patients.

• 종양간호연구
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• 제11권1호
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• pp.1-8
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• 2011

Purpose: The purpose of this study was to identify the types of venous access devices (VAD) for cancer patients and investigate the factors related to the insertions of central venous catheter (CVC) in cancer patients. Methods: The subjects were 379 cancer patients. A retrospective review of all patients who were discharged from a cancer unit from November 1st to 21st in 2008 was done using a structured questionnaire. Results: A total of 82 CVC (21.6%) was inserted among 379 patients for administering anticancer therapy. There were statistically significant differences in age, length of stay (LOS), cumulative LOS, medical department, history of CVC insertion, cancer category, and albumin level between patients using peripheral intravenous (IV) catheters and CVC. In addition, factors influencing the use of CVC were LOS (odds ratio [OR]=0.286, confidence interval [CI]=1.043-1.124), history of CVC insertion (OR=3.920, CI=0.128-0.637), albumin level (OR=1.010, CI=1.879-8.179), cumulative LOS (OR=1.010, CI=1.001-1.018), and hematological diseases (OR=4.863, CI=2.162-10.925). Conclusion: We found that central venous catheterization for anticancer therapy was minimal even though CVC was safe and effective device for IV access. It is necessary to develop a strategy to use VADs efficiently and timely for cancer patients.

• Journal of Chest Surgery
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• 제33권5호
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• pp.385-390
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• 2000

Background: To review the experience that used both ventricular assist device(VAD) and extracorporeal membrane oxygenation(ECMO) for children with congential heart disease requiring postcardiotomy mechanical circulatory support. Material and Method: Between March 1993 and May 1995, we applied mechanical assist device using centrifugal pump to the 16 patients who failed to be weaned from cardiopulmonary bypass(n=15) or had been in cardiogenic shock in intensive care unit(n=1). The diagnosis were all congenital heart diseases and the ages of patients ranged from 20 days to 10 years (mean age=2.5$\pm$3.5 years). Result: The methods of mechanical circulatory support were LVAD(n=13), BVAD (n=1), and ECMO(n=2). The mean assist times were 54.0$\pm$23.7 hours. Post-assist complications were in orders: bleeding, acute renal failure, ventricular failure, respiratory failure, infection, and neurologic complication. It was possible for 9 patients(56.3%) to be weaned from assist device and 5 patients(31.3%) were discharged from hospital. There was no statistical significant between hospital discharged group and undischarged group by age, body weight, cardiopulmonary bypass time, and assist time. Conclusion: The ventricular assist device is an effective modality in salvaging the patient who failed to be weaned from cardiopulmonary bypass, but multiple factors must be considered for improving the results of mechanical circulatory support ; such as patient selection, optimal time of starting the assist device, and prevention and management of the complications.

• 한국정보통신학회논문지
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• 제19권6호
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• pp.1327-1332
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• 2015

본 연구에서는 WiFi 무선망을 통한 VoIP 서비스의 품질에 영향을 주는 요소들을 분석하였다. VoIP 품질에 영향을 주는 요소로는 VoIP 통화의 수, WiFi 구간의 비음성 트래픽, 백본망내의 패킷 손실율과 단대단 지연등이 있다. WiFi 구간내 비음성 트래픽이 없으며 백본망의 패킷 손실율이 4%이고 단대단 지연이 90msec인 경우 G.729a 코덱으로는 12통화가 가능하며 G.729a VAD 코덱으로는 27통화까지 서비스 가능하였다. 분석결과 WiFi 구간의 데이터 트래픽과 TCP/IP망내 지연 및 패킷 손실율이 통화품질에 많은 영향을 주고 있는 것으로 확인되었으며 양질의 통화를 제공하기 위해서는 단대단 지연과 패킷 손실율을 최소한으로 유지하는 것 외에도 AP내에서 일종의 VoIP 호 접속 제어를 할 필요가 있는 것으로 판단된다.

• Archives of Pharmacal Research
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• 제27권11호
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• pp.1147-1153
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• 2004

Bladder cancer is a common cancer with high risk of recurrence and mortality. Intravesicle chemotherapy after trans-urethral resection is required to prevent tumor recurrence and progression. It has been known that antioxidants enhance the antitumor effect of bacillus Calmette-Guerin (BCG), the most effective intravesical bladder cancer treatment. Capsaicin, the major pungent ingredient in genus Capsicum, has recently been tried as an intravesical drug for overactive bladder and it has also been shown to induce apoptotic cell death in many cancer cells. In this study, we investigated the apoptosis-inducing effect and alterations in the cellular redox state of capsaicin in MBT-2 murine bladder tumor cells. Capsaicin induced apoptotic MBT-2 cell death in a time- and dose-dependent manner. The capsaicin-induced apoptosis was blocked by the pretreatment with Z-VAD-fmk, a broad-range caspase inhibitor, or Ac-DEVD-CHO, a caspase-3 inhibitor. In addition to the caspase-3 activation, capsaicin also induced cytochrome c release and decrease in Bcl-2 protein expression with no changes in the level of Bax. Furthermore, capsaicin at the concentration of inducing apoptosis also markedly reduced the level of reactive oxygen species and lipid peroxidation, implying that capsaicin may enhance the antitumor effect of BCG in bladder cancer treatment. These results further suggest that capsaicin may be a valuable intravesical chemotherapeutic agent for bladder cancers.

• 음성과학
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• 제15권2호
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• pp.55-65
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• 2008

Recently, the multi-model based speech recognizer has been used quite successfully for noisy speech recognition. For the selection of the reference HMM (hidden Markov model) which best matches the noise type and SNR (signal to noise ratio) of the input testing speech, the estimation of the SNR value using the VAD (voice activity detection) algorithm and the classification of the noise type based on the GMM (Gaussian mixture model) have been done separately in the multi-model framework. As the SNR estimation process is vulnerable to errors, we propose an efficient method which can classify simultaneously the SNR values and noise types. The KL (Kullback-Leibler) distance between the single Gaussian distributions for the noise signal during the training and testing is utilized for the classification. The recognition experiments have been done on the Aurora 2 database showing the usefulness of the model compensation method in the multi-model based speech recognizer. We could also see that further performance improvement was achievable by combining the probability density function of the MCT (multi-condition training) with that of the reference HMM compensated by the D-JA (data-driven Jacobian adaptation) in the multi-model based speech recognizer.