• 생명과학회지
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• 제28권12호
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• pp.1406-1415
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• 2018

본 연구는 어성초(Houttuynia cordata Thunb)의 메탄올 추출에 의한 유기 용매별 분획물에서 항산화 효과를 근거로 산화적 스트레스에 의한 HaCaT 세포보호 효과를 확인하였다. 용매별 분획물의 항산화 활성은 시료의 농도가 증가할수록 DPPH에 대한 전자공여능도 증가하였으며, $ED_{50}$은 ethyl acetate (EtOAc) 분획물에서 $175{\mu}g/ml$로 가장 높게 나타났다. $H_2O_2$에 의해 유도된 HaCaT 세포의 세포사멸($IC_{50}$)에 대하여 Hc-EtOAc 분획물은 농도 의존적으로 유의적인 세포 생존율과, $100{\mu}g/ml$ 농도에서 74%의 세포보호 효과를 나타내었다. 한편 $100{\mu}g/ml$의 Hc-EtOAc 분획물을 6 및 24시간 동안 HaCaT 세포에 처리하여 유전자 발현 양상을 분석하였다. 2 배 이상 발현이 증가된 유전자들은 신호전달, 세포분열, 항산화 활성, 상피세포 증식 등에 작용하는 것으로 나타났다. 특히 항산화 활성에 관여할 것으로 추정되는 유전자는 전염증성 사이토카인인 IL1B, TNF, 그리고 IL6 등 이었으며, 이들 유전자의 상위 조절자로써 TLR4가 확인되었다. IL1B, TNF, 그리고 IL6 유전자의 활성을 검증하기 위하여 qRT-PCR을 수행한 결과, $100{\mu}g/ml$ 이상의 Hc-EtOAc 분획물 처리군에서 2 배 이상 발현이 증가한 것으로 나타났다. 상위 조절자 TLR4 단백질의 활성 역시 Hc-EtOAc 분획물에 의해 증가되었다. 이상의 결과, Hc-EtOAc 분획물에 의한 항산화 활성은 TLR4로부터 IL1B, TNF, IL6과 같은 사이토카인을 경유하는 것으로 예측된다.

• 대한의생명과학회지
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• 제18권3호
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• pp.276-282
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• 2012

High-intensive endurance exercises induce cell changes in body, changes in structures and functions of the heart, the muscles, the cartilages, and the liver, as well as increase of inflammatory cytokine. The purpose of this study was to estimate the biochemical changes in the liver and muscles during ultra-marathon race (100 km) by sections. The blood of the subjects was collected before the marathon as a control in order to analyze serum creatine kinase (CK), lactic dehydrogenase (LDH), asprtate aminotransferase (AST), alanine aminotransferase (ALT), total(T)-bilirubin, direct(D)-bilirubin, total protein, albumin, uric acid, gamma-glutamyltranspeptidase (${\gamma}$-GTP), alkaline phosphatase (ALP), creatinine, blood urea nitrogen (BUN), and high sensitive C-reactive protein (hs-CRP) concentrations. The CK, LDH, D-bilirubin, AST and ALT concentrations at 50 km and 100 km were significantly increased compared to the control (P<0.05). The markers at 100 km were higher than those at 50 km (P<0.05). The T-bilirubin and hs-CRP concentrations showed no difference among the groups, whereas the markers at 100 km were higher than those of the control and at 50 km (P<0.05). In conclusion, this study shows that the ultra-marathon race (100 km) may induce the damage of the skeletal muscle, liver and kidney, intravascular hemolysis and inflammatory responses.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8101-8105
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• 2014

Background: Although mucinous adenocarcinoma has been recognized for a long time, whether it is associated with a poorer prognosis in colorectal cancer patients is still controversial. Many studies put emphasis on mucinous adenocarcinoma containing mucin component ${\geq}50%$. Only a few studies have analyzed cases with a mucin component <50%. Objectives: This study aimed to analyze the prognostic value of different mucin component proportions in patients with stage III rectal cancer. Materials and Methods: Clinical, pathological and follow-up data of 136 patients with the stage III rectal cancer were collected. Every variable was analyzed by univariate analysis, then multivariate analysis and survival analysis were further performed. Results: Univariate analysis showed pathologic T stage, lymphovascular invasion, and histological subtype were statistically significant for DFS. Pathologic T stage was significant for OS. Histological subtype and lymphovascular invasion were independent prognostic factors in multivariate analysis for DFS, and histological subtype was the only independent prognostic factor for OS. Survival curves showed the survival time of mucinous adenocarcinoma (MUC) was shorter than non-MUC (adenocarcinomas with a mucin component <50% and without mucin component). Conclusions: Histological subtype (tumor with different mucin component) was an independent prognostic factor for both DFS and OS. Patients with MUC had a worse prognosis than their non-MUC counterparts with stage III rectal carcinoma.

• 한국컴퓨터정보학회논문지
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• 제6권2호
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• pp.108-115
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• 2001

SDH(synchronous digital hierarchy)를 기본으로 한 SHR(self-healing ring) 네트워크는 장애가 발생할 경우 프로세스를 재구성할 수 있으며 APS 프로토콜을 사용하고 있다. 본 연구에서는 양방향으로 트래픽을 전송할 수 있고 두 개의 선로를 갖는 BSHR/2(two fiber bidirectional SHR)네트워크에서의 장애 복구 시간을 측정하였다. 이를 위해 APS(automatic protecti switching) 프로토콜을 분석하고 ITU-T G.841이 제시하는 최대 장애 복구 시간인 50㎳내에 장애를 복구하기 위해 필요한 각 노드들의 프로세싱 시간 영역을 제시하였다. 또한 다중 장애에서 SD(signal degrade) 장애가 선행된 후 다시 SF(signal failure) 장애가 발생하는 경우와 SF 장애가 선행된 후 다시 SF 장애가 발생하는 경우에 대해서도 분석하였으며, 어떠한 경우에도 50㎳내의 장애를 복구할 수 있었다.

• 전기학회논문지
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• 제65권9호
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• pp.1504-1510
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• 2016

The aim of this study is to improve properties both glass transition temperature($T_g$) and coefficient of thermal expansion(CTE) using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40, 50, 60wt%)+surface modified nano alumina(1_phr) composites. 20 kinds specimen were prepared with containing micro, nano alumina and GDE as a micro composites(10, 20, 30, 40, 50, 60, 70wt%) or a nano/micro alumina composites(1phr/40, 50, 60wt%). Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The glass transition temperature and coefficients of thermal expansion was evaluated by DSC and TMA. The glass transition temperature decreased and coefficients of thermal expansion become smaller with filled contents of epoxy/micro alumina composites. On the other hand, $T_g$ and CTE as GDE addition variation(1,2,3,5g) of epoxy/micro-nano alumina composites decreased and increased respectively.

• Journal of Korean Neurosurgical Society
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• 제50권3호
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• pp.264-267
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• 2011

A 50-year-old man presented bilateral hypesthesia on and below the T6 dermatome and paresthesia. Magnetic resonance imaging (MRI) showed an intraspinal extradural tumor, which located from the 6th thoracic vertebral body to the upper margin of the 7th vertebral body, continuing dumbbell-like through the intervertebral foramen into the right middle thorax suggesting a neurogenic tumor (neurofibroma or neurilemmoma). With the patient in a prone position, we exposed and excised the tumor via a one stage posterior approach through a hemi-laminictomy of T6. Histologic examination showed a grade 1 meningothelial meningioma, according to the World Health Organization classification. Initially, we assumed the mass was a schwannoma because of its location and dumbbell shape. However, the tumor was actually a meningioma. Postoperatively, hypesthesia resolved completely and motor power of the leg gradually full recovered. A postoperative MRI revealed no evidence of residual tumor.

• 한국자기학회지
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• 제4권2호
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• pp.126-129
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• 1994

희토류원소 Pr의 첨가가 Fe-B계 비정질합금의 자왜에 미치는 영향을 조사하기 위하여 비정질 $Fe_{86-x}B_{14}Pr_{x}(2{\leq}x{\leq}8\;at.%)$ 합금을 급속응고법을 이용하여 제조하였다. 급 속응고상태 비정질 $Fe_{86-x}B_{14}Pr_{x}$ 합금의 포화자왜는 Pr이 증가할 수록 증가하여 x=8에 서 약 50 ppm이 얻어졌다. 특히 $300^{\circ}C$에서 2시간 열처리된 비정질 $Fe_{84}B_{14}Pr_{2}$ 합금의 포화자왜는 70 ppm으로 증가하였다. $300^{\circ}C$에서 2시간 열처리된 비정질 $Fe_{84}B_{14}Pr_{2}$ 합금의 교류 자기이력손실 및 교류투자율$(f=50\;kHz,\;B_{m}=0.1\;T)$은 각각 15 W/kg, $5.5{\times}10^{3}$이었다.

• 한국지반공학회논문집
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• 제18권2호
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• pp.137-146
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• 2002

본 연구에서는 국내 해성퇴적 연약지반의 압밀특성을 실험적으로 규명하기 위하여 현장에서의 픽에조콘을 이용한 간극수압소산시험을 수행하고 동일한 위치와 심도에서 채취한 비교란시료를 이용하여 실내에서 Howe cell 압밀시험을 포함한 역학시험과 물성시험을 수행하였다. 이를 근거로 howe cell 압밀시험으로부터 구한 수평압밀계수$(c_r)$와 피에조콘 소산시험으로부터 구한 압밀도 50%에 해당하는 소산시간$(t_{50})$의 관계를 회귀분석을 통하여 실험식을 제안하였으며 이 실험식과 기존의 여러 학자들에 의해 제안된 이론해와의 관계를 비교하였다. 이에 의하면 실린더형 공동팽창이론에 근거한 Torstensson(1977)의 이론해와 변형률경로법에 근거한 Houlsby와 Teh(1988)의 이론해에 비교적 유사한 경향을 보이는 것으로 나타났다

• 한국작물학회지
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• 제49권5호
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• pp.381-388
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• 2004

In Korea, production of super sweet corn has been economically feasible and is substituting for traditional sweet corn due to better flavor in recent years. Major limiting factors for super sweet corn production are low field emergence and low seedling vigor. The optimum water potential (WP) for the priming of normal and aged seeds of dent, sweet (su) and super sweet (sh2) corns was studied to improve low seed quality. Seeds were primed at 0, -0.3, -0.6, -0.9, and -1.2 MPa of polyethylene glycol (PEG) 8000 solution at $15^{\circ}C$ for 2 days. Priming effects differed depending on the type of corn, seed quality, and WP of PEG solution. Although WP of priming solution did not influence the emergence rate of extremely high quality normal dent corn seeds, it reduced time to $50\%$ emergence (T50) and increased plumule weight. In contrast, the emergence rate of aged field corn was improved by seed priming at 0 MPa and plumule weight and $\alpha-amylase$ activity was enhanced. The optimum WP for both normal and aged sweet and super sweet corn seeds was between -0.3 and -0.6 Mpa. At the optimum WP emergence rate, $\alpha-amylase$ activity, and content of DNA and soluble protein increased, while T50 and leakage of total sugars and electrolytes reduced.

• Journal of Power Electronics
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• 제18권3호
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• pp.694-701
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• 2018

This paper proposes a new single-phase power converter topology for changing the frequency of AC voltage. The proposed single-phase frequency converter (SFC) includes a T-type multi-level power converter (TMPC), a frequency decoupling transformer (FDT) and a digital signal processor (DSP). The TMPC can convert a 60 Hz AC voltage to a DC voltage and then convert the DC voltage to a 50 Hz AC voltage. Therefore, the output currents of the two T-type power switch arms have 50 Hz and 60 Hz components. The FDT is used to decouple the 50 Hz and 60 Hz components. The salient feature of the proposed SFC is that only one power electronic converter stage is used since the functions of the AC-DC and DC-AC power conversions are integrated into the TMPC. Therefore, the proposed SFC can simplify both the power circuit and the control circuit. In order to verify the functions of the proposed SFC, a hardware prototype is established. Experimental results verify that the performance of the proposed SFC is as expected.