• 한국전자파학회논문지
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• 제14권1호
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• pp.68-74
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• 2003

본 논문에서는 Ka-band 위성중계기에 사용되어지는 수신하향변환기(Receiver-Downconverter) 모듈의 설계 및 제작 그리고 시험 결과에 대하여 기술하였다. 개발된 수신하향변환기는 30.6 GHz∼31 GHz대역의 신호를 입력으로 받아들여 20.8 GHz∼21.2 GHz 대역의 신호를 출력하는 일종의 Downconverter 이지만, 모듈의 입력단에 저잡음 증폭부가 포함된 수신기의 역할도 하고 있다 개발된 모듈은 제작과정 및 시험과정에 있어 위성중계기 부품 제작 규정을 준수하였으며, 그 개발된 성능은 현재까지 알려진 국내외 유사 부품중의 최고의 성능을 보여주고 있다. 측정된 모듈의 성능은 상온에서 1.9 dB의 잡음지수, 55 dB 이득, 58 dBc의 C/I3 값을 보여주고 있다. 제작된 모듈의 크기는 93 mm${\times}$84 mm${\times}$26 mm이며 무게는 240 g으로서 국내외 유사 제품에 비해 소형이다.

• 한국콘텐츠학회논문지
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• 제10권8호
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• pp.240-248
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• 2010

본 논문은 SLS의 함유정도를 다르게 한 A(0%), B(1.1%), C(2.2%)의 세가지 실험세치제를 제작하여 구강 내 변화를 50명씩 세 그룹(A, B, C)으로 나누어 실험하였다 본 연구결과 SLS함량에 따른 세치제의 4주간 사용 후 3집단의 치면세균막 검사( PHP )에서 집단간차이가 나타났고 SLS함량이 높을수록 PHP의 지수가 낮아졌다. 또한 간이구강위생지수(OHI-S)에서는 A, B, C 세집단 모두에서 OHI-S 값이 줄었다. 또한 PHP와 OHI-S는 높은 상관성을 보였다. SLS함량에 따른 세치제의 4주간사용 후 3집단의 타액분비량 측정 시 SLS함량이 높아질수록 타액량이 감소하였고, 타액의 점조도 및 pH에는 변화가 없었다. SLS가 구강건조를 유발함을 뒷받침하는 결과로 SLS와 타액의 분비량은 음의 상관관계를 보였다.

• 한국결정성장학회지
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• 제19권4호
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• pp.165-171
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• 2009

기존의 합성방법에 사용되는 백금 도가니의 단점을 보완할 수 있는 알루미나 도가니를 사용하여 천연 및 기존의 합성루비와 유사한 적색의 투명한 결정을 성장시켰다. $PbO-B_2O_3$ 가 흔합된 플럭스를 사용하여 $915{\sim}1350^{\circ}C$의 온도에서 약 240시간 실험 후 최대 9.02 ${\times}$ 6.36 mm 투명한 적색의 결정이 성장되었다. 이 결정을 보석학적 기초검사를 통하여 굴절률, 내포물, 비중 등의 특성과 FT-IR, UV-VIS spectrometer 및 XRD 를 사용하여 기존의 합성루비 및 천연루비의 특성과 비교분석하였다.

• 소성∙가공
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• 제17권4호
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• pp.240-248
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• 2008

The effect of alloying elements(Mn, S, Mo, B) on the high temperature deformation behavior of Fe-29%Ni-17%Co (Kovar) alloy were investigated. And the effect of high temperature oxidation on the hot ductility was also studied. The hot ductility of Kovar alloy was drastically increased with the addition of Mn and lowering of S content. It has been found that the brittle intergranular fracture at high temperature cracking is closely associated with the FeS sulfide along the grain boundary. When Mn was added, the type of sulfide was changed to MnS from FeS and ductile intergranular fracture and transgranular fracture were promoted. The formation of oxide layer was found to have minimized the hot ductility of the Kovar alloy significantly. Grain boundary micro-cracks in the internal oxide region were noted following deformation due to high temperature, one of which acting as a notch that caused the poor hot workability of the oxidized specimen. The addition of Mo to the Kovar alloy could also retard the decrease in the hot ductility of the oxidized specimen through the prevention of notching due to internal oxidation. Hot ductility was remarkably improved by the addition of Boron. The improvement of hot ductility results from the grain boundary migration mainly due to the dynamic recrystallization at lower temperature range ($900{\sim}1000^{\circ}C$).

• 한국의류산업학회지
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• 제12권2호
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• pp.240-245
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• 2010

The effects of monazite and fixing agents on cotton fabric dyed with Perilla frutescens var. acuta extract were investigated. The proper monazite treatment concentration, temperature and time were 10%(o.w.b.), $50^{\circ}C$ and 60minutes. By various fixing agent treatment, $FeSO_4$ showed a relatively high K/S value and the order of K/S value decreased as follows, cation surface active agents, soybean and NaCl. And the monazite and $FeSO_4$ fixing agent showed higher anion emissity than those of untreated cotton and other fixing agents. The cotton fabrics showed improved color fastness by monazite and fixing agents treatments with the exception of light fastness. And the cotton fabrics fixed with fixing agents were showed effective bacterial reduction with the exception of NaCl.

• Journal of the Optical Society of Korea
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• 제11권3호
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• pp.93-96
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• 2007

We demonstrate a 240 km reach DWDM-PON at 8-Gb/s capacity based on wavelength-locked Fabry-Perot laser diodes and a bidirectional EDFA. We achieve a packet-error-free transmission in both the 64 upstream and 64 downstream channels, guaranteeing a 125 Mb/s symmetric data rate per user. There is no noticeable dispersion penalty. The power penalty due to the crosstalk induced by the DWDM transmission and detuning between AWGs is less than 1.2 dB, when the detuning is within ${\pm}0.12 nm$.

• Biomolecules & Therapeutics
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• 제17권3호
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• pp.219-240
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• 2009

Since NF-${\kappa}B$ has been identified as a transcription factor associated with immune cell activation, groups of researchers have dedicated to reveal detailed mechanisms of nuclear factor of ${\kappa}B$ (NF-${\kappa}B$) in inflammatory signaling for decades. The various molecular components of NF-${\kappa}B$ transcription factor pathway have been being evaluated as important therapeutic targets due to their roles in diverse human diseases including inflammation, cystic fibrosis, sepsis, rheumatoid arthritis, cancer, atherosclerosis, ischemic injury, myocardial infarction, osteoporosis, transplantation rejection, and neurodegeneration. With regards to new drugs directly or indirectly modulating the NF-${\kappa}B$ pathway, FDA recently approved a proteasome inhibitor bortezomib for the treatment of multiple myeloma. Many pharmaceutical companies have been trying to develop new drugs to inhibit various kinases in the NF-${\kappa}B$ signaling pathway for many therapeutic applications. However, a gene knock-out study for $IKK{\beta}$ in the NF-${\kappa}B$ pathway has given rise to controversies associated with efficacy as therapeutics. Mice lacking hepatocyte $IKK{\beta}$ accelerated cancer instead of preventing progress of cancer. However, it is clear that pharmacological inhibition of $IKK{\beta}$ appears to be beneficial to reduce HCC. This article will update issues of the NF-${\kappa}B$ pathway and inhibitors regulating this pathway.

• Genomics & Informatics
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• 제12권4호
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• pp.240-246
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• 2014

Mutation in HNF1B, the hepatocyte nuclear factor-$1{\beta}$ (HNF-$1{\beta}$) gene, results in maturity-onset diabetes of the young (MODY) 5, which is characterized by gradual impairment of insulin secretion. However, the functional role of HNF-$1{\beta}$ in insulin secretion and glucose metabolism is not fully understood. We identified a family with early-onset diabetes that fulfilled the criteria of MODY. Sanger sequencing revealed that a heterozygous P159L (CCT to CTT in codon 159 in the DNA-binding domain) mutation in HNF1B was segregated according to the affected status. To investigate the functional consequences of this HNF1B mutation, we generated a P159L HNF1B construct. The wild-type and mutant HNF1B constructs were transfected into COS-7 cells in the presence of the promoter sequence of human glucose transporter type 2 (GLUT2). The luciferase reporter assay revealed that P159L HNF1B had decreased transcriptional activity compared to wild-type (p < 0.05). Electrophoretic mobility shift assay showed reduced DNA binding activity of P159L HNF1B. In the MIN6 pancreatic ${\beta}$-cell line, overexpression of the P159L mutant was significantly associated with decreased mRNA levels of GLUT2 compared to wild-type (p < 0.05). However, INS expression was not different between the wild-type and mutant HNF1B constructs. These findings suggests that the impaired insulin secretion in this family with the P159L HNF1B mutation may be related to altered GLUT2 expression in ${\beta}$-cells rather than decreased insulin gene expression. In conclusion, we have identified a Korean family with an HNF1B mutation and characterized its effect on the pathogenesis of diabetes.

• Journal of Microbiology
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• 제34권3호
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• pp.236-240
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• 1996

Rifampin is the most powerful drug for treating leprosy and tuberculosis today. It inhibits initiation and elongation of RNA transcription by binding to $\beta$-subunit of RNA polymerase, leading to kill mycobacteria. We isolated one variant strain of Mycobacterium leprae from 24 Korean leprosy patients who are less susceptible to rifampin or have suffered from relapse by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) of the rpoB gene. Direct sequencing of the rpoB region of M. leprae variant revealed missense mutations which altered the amino acids sequenceof RpoB to Ser-464, Arg-465, Arg-467 and Ala-468. This is the first finding on rpoB gene mutation of M. leprae from Korean patients ; moreover the mutant type was found to be different from the previously reported cases in other countries.

• 한국식품영양학회지
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• 제20권2호
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• pp.240-244
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• 2007

In this study, we found that the methanolic extract of Areca catechu repressed expression of the tyrosinase gene in B16 mouse melanoma cells containing a tyrosinase promoter. Extract concentrations of 100 ${\mu}$g/ml and 500 ${\mu}$g/ml exhibited tyrosinase gene expression rates of aproximately 62% and 48%, respectively, compared to the control. The fraction layers consisting of ethyl acetate, butyl alcohol, and water showed repressive effects on the tyrosinase gene. In particular, the butyl alcohol fraction highly repressed at 100 ${\mu}$g/ml and 500 ${\mu}$g/ml. In the MTT assay, the methanolic extracts exhibited very low cytotoxicities at 1 ${\mu}$g/ml, 10 ${\mu}$g/ml, and 100 ${\mu}$g/ml.