• Biotechnology and Bioprocess Engineering:BBE
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• 제5권2호
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• pp.130-135
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• 2000

The characteristics of two different modes of perfusion culture, intermittent and continuous bleedings, were investigated by culturing the hybridoma cells producing von Willebrand Factor (vWF) monoclonal antibody (McAb) in a 15 L bioreactor without clogging the filter. Both culture methods exhibited similar profiles of cell density and metabolite concentrations during the culture period at the cell concentration of around 1${\times}$107 cells/mL. When the perfusion rate was increased, the intermittrnt bleeding culture showed problems of ammonia accumulation and decrease of cell viability. The continuous bleeding culture in terms of nutrient consumption and metabolite production kinetics. But the analysis of specific oxygen consumption rate showed that the specific oxygen consumption rate of intermittent bleeding culture was similar to that of exponential growth phase. The continuous bleeding culture showed higher specific oxygen consumption rate of intermittent bleeding culture. finally we proved the possibility of long-term operation of continuous bleeding culture and produced approximately 40 g of vWF McAb in a 15L bioreactor after one-month operation.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.681-684
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• 2012

• 동의생리병리학회지
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• 제18권3호
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• pp.930-934
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• 2004

The purpose of this research is to evaluate the change of Yangdorak in women who work in three shifts and during the day. In this research, seventy women who work during the day and thirty women who work in three shifts, all of whom are working at Woo shin hyang Oriental Hospital and Kang dong gu Office, were the two subjects for it. We evaluated and compared the Yangdorak appeared in two groups and studied the relations with clinical symptoms between the two. In Yangdorak, the women who work in three shifts were evaluated low numerical value in liver meridian, heart meridian, kidney meridian compared with the women who work during the day. Based on the results above, we can state that the women who work in three shifts suffer from severe dysmenorrhea, insomnia, cold hypersensitivity.

• 한국재료학회지
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• 제9권8호
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• pp.854-857
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• 1999

Fe-Se-Te계(FeSe(sub)1-xTe(sub)x, x=0.2, 0.5, 0.8)의 특성을 X-선 회절법 및 Mossbauer 분광법에 의해 조사하였다. 결정구조는 세 시료 모두 주된 tetragonal PbO 구조와 hexagonal NiAs 구조가 일부 혼합된 형태를 보였으며 x=0.5의 경우 tetragonal 구조의 격자상수 값은 a=3.795$\AA$, c=5.896$\AA$ 이며 c/a=1.55로 나타났다. 다양한 온도변화에 의해 측정된 Mossbauer 스펙트럼은 전체 시료 모두 초미세 자기구조를 갖지 않는 강한 이중선(doublet)이 관측되었다. 조성 및 온도변화에 대해 뚜렷한 선형(line shape)의 변화는 관측되지 않았으나 결합상태에 약간의 변화를 보였다. 이성질체 이동(isomer shift)값과 사중극자 분열(quadrupole splitting)값 및 온도의존성을 분석한 결과 Fe는 low spin이 +2가 상태로 존재하며 강한 공유 결합상태임을 알 수 있었다. x=0.8의 경우 이성질체 이동값의 온도변화는 제2차 도플러 효과(second order Doppler effect)의 영향인 것으로 나타났다.

• Clinical and Experimental Reproductive Medicine
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• 제47권3호
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• pp.213-220
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• 2020

Objective: The aim of this study was to explore the potential adverse effect of spontaneously decreasing serum estradiol (SE) levels on in vitro fertilization (IVF) outcomes. Methods: This retrospective single-subject study analyzed IVF cycles conducted at a hospital IVF unit between 2010 and 2017. Overall, 2,417 cycles were analyzed. Only cycles with spontaneously decreasing SE before human chorionic gonadotropin (hCG) triggering were included. Each patient served as her own control, and subsequent cycles were analyzed for recurrent SE decreases. The main outcome was the number of oocytes retrieved. Results: Cycle characteristics were similar between the study (SE decrease) and control groups, with the exception of the median SE on the day of hCG triggering (899.7 pg/mL; interquartile range [IQR], 193-2,116 pg/mL vs. 1,566.8 pg/mL; IQR, 249-2,970 pg/mL; p< 0.001). The study group, relative to the control group, had significantly fewer total oocytes (5 [IQR, 2-9] vs. 7 [IQR, 3-11]; p= 0.002) and significantly fewer metaphase II (MII) oocytes (3 [IQR, 1-6] vs. 4 [IQR, 2-8]; p= 0.001) retrieved. The study group had fewer cleavage-stage embryos than the control cycles (3 [IQR, 1-6] vs. 4 [IQR, 2-7]; p= 0.012). Compared to cycles with a ≤ 20% SE decrease, cycles with a > 20% decrease had significantly fewer total and MII oocytes retrieved. SE decrease recurred in 12% of patients. Conclusion: A spontaneous decrease in SE levels adversely affected IVF outcomes, with a linear correlation between the percentage decrease and the number of oocytes retrieved. SE decrease can repeat in later cycles.

• 한국환경과학회지
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• 제18권12호
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• pp.1411-1416
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• 2009

Several adsorbents were tried to remove the selenium ions from industrial wastewater and the following ascending order of the adsorption performance for the selenium at pH 9 was observed: cation exchange resin < chelate resin < zeolite < brown marine algae < granular activated carbon < anion exchange resin. Initial concentration of selenium(146 mg/L) in industrial wastewater was reduced to 63 mg/L of selenium at pH 9 by neutralization process. The maximum uptake of Se calculated from the Langmuir isotherm with anion exchange resin was 0.091 mmol/g at pH 10 and that with granular activated carbon was 0.083 mmol/g at pH 6. The affinity coefficients of Se ion towards anion exchange resin and granular activated carbon were 3.263 L/mmol at pH 10 and 0.873 L/mmol at pH 6, respectively. The sorption performance of anion exchange resin at the low concentration of Se, namely, was much better than that of granular activated carbon. The Se ions from industrial wastewater throughout neutralization process and two steps of adsorption using anion exchange resin was removed to 97.7%.

• 천문학회보
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• 제36권1호
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• pp.68.2-68.2
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• 2011

KVN은 2008년말에 3 대의 망원경 구축을 완료하고, 2009년에는 22/43 GHz 수신기를 각 망원경에 설치하였으며, 2009년말부터는 이 망원경들을 이용한 단일안테나 연구관측 및 VLBI 시험관측에 착수하였다. 2010년에는 86 Hz 수신기 1 대를 도입하였고, 129 GHz 수신기의 경우 믹스 개발을 완료한 후 현재 수신기 1대를 조립하고 있다. 적어도 1 set의 86/129 Hz 수신기가 금년 내에 연세망원경에 설치되어 시험관측이 수행될 예정이다. 2010년에는 또한 안테나의 크래딩 작업을 완료하여 지향성을 개선하였으며, 단일 안테나 연구관측 결과를 논문으로 생성하기도 하였다. 2011년말부터는 VLBI 연구관측에 착수할 예정이며, 관측시간의 50 %를 일본의 VERA와 공동관측에 활용할 예정이다. 2010년말에는 동아시아VLBI센터 건물의 건설이 착수되었으며, 2012년 6월경에 완공될 예정이다.

• 한국항해항만학회지
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• 제29권3호
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• pp.181-187
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• 2005

국내 최초로 운항예정인 수륙양용 아쿠아버스의 운항 리스크를 낮추고 안전을 확보하기 위하여 운항예정 해역인 월미도와 영종도간 수로에 대한 자연적환경과 해상교통량을 조사하고, 그들의 위험요소를 분석하였다. 그리고 아쿠아버스의 통항 안전 확보를 위하여 경계수역 지성, 잔용선착장 설치, 운항관리 방안 등을 제안하였다.

• 한국재료학회지
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• 제33권5호
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• pp.189-194
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• 2023

This study uses first-principles calculations to investigate the mechanical properties and effect of strain on the electronic properties of the 2D material 1H-PbX₂ (X: S, Se). Firstly, the stability of the 1H Pb-dichalcogenide structures was evaluated using Born's criteria. The obtained results show that the 1H-PbS₂ material possesses the greatest ideal strength of 3.48 N/m, with 3.68 N/m for 1H-PbSe₂ in biaxial strain. In addition, 1H-PbS₂ and 1H-PbSe₂ are direct semiconductors at equilibrium with band gaps of 2.30 eV and 1.90 eV, respectively. The band gap was investigated and remained almost unchanged under the strain ε_xx but altered significantly at strains ε_yy and ε_bia. At the fracture strain in the biaxial direction (19 %), the band gap of 1H-PbS₂ decreases about 60 %, and that of 1H-PbSe₂ decreases about 50 %. 1H-PbS₂ and 1H-PbSe₂ can convert from direct to indirect semiconductor under the strain ε_yy. Our findings reveal that the two structures have significant potential for application in nanoelectronic devices.

• 대한방사선기술학회지:방사선기술과학
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• 제40권1호
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• pp.135-142
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• 2017

천연물에 존재하는 셀레늄(Se)은 생체의 산화환원작용을 주관하는 중요한 단백질의 하나인 셀레늄함유단백질(selenoprotein)의 중요한 요소로 알려져 있다. 셀레늄(Se)을 Rat에 경구 투여하여 10 Gy의 방사선을 조사 시킨 후 갑상선을 표적 장기로 삼고 1일, 7일, 21일 기간에 따른 혈구성분의 변화, 갑상선호르몬(T3, T4)의 변화, 항산화효소((Glutathione Peroxidase, GPx)의 활성 변화, 갑상선 조직 변화 관찰을 통하여 셀레늄(Se)의 방사선 방호 작용을 알아보고자 하였다. 실험결과 조혈 면역계(혈색소농도, 호중구, 혈소판)에서 회복을 보이는 유의한 방호 효과가 있었다(p<0.05). 항산화효소인 Glutathione Peroxidase(GPx) 활성과 표적 장기인 갑상선 호르몬(T3, T4)의 활성 변화 결과에서도 유의성 있는 활성 변화를 보였으며(p<0.05), 조직 변화 관찰에서는 방사선 처리에 의한 세포 괴사를 일으킨 갑상선 세포 손상 보호 효과가 있음을 확인하였다. 따라서, 셀레늄(Se)은 떨어진 생체의 면역 활성 효과를 유도함으로써 방사선 방어제로 활용될 수 있을 것이라 판단된다.