• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.1
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• pp.52-58
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• 2006

Single-electron transistor (SET)-based logic cells and SET/FET hybrid integrated circuits have been fabricated on SOI chips. The input-output voltage transfer characteristic of the SET-based complementary logic cell shows an inverting behavior where the output voltage gain is estimated to be about 1.2 at 4.2K. The SET/FET output driver, consisting of one SET and three FETs, yields a high voltage gain of 13 and power amplification with a wide-range output window for driving next circuit. Finally, the SET/FET literal gate for a multi-valued logic cell, comprising of an SET, an FET and a constant-current load, displays a periodic voltage output of high/low level multiple switching with a swing as high as 200mV. The multiple switching functionality of all the fabricated logic circuits could be enhanced by utilizing a side gate incorporated to each SET component to enable the phase control of Coulomb oscillations, which is one of the unique characteristics of the SET-based logic circuits.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.3
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• pp.781-784
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• 2012

The aim of this study was to evaluate the effect of the adenovirus-mediated double suicide gene (CD/TK) for selective killing of gastric cancer cells. Gastric cancer cells SCG7901 and normal gastric epithelial cell lines were infected by adenoviruses Ad-survivin/GFP and Ad-survivin/CD/TK. GFP expression and CD-TK were detected by fluorescence microscopy and reverse transcriptase polymerase chain reaction (RT-PCR), respectively. After treatment of the infected cells with the pro-drugs ganciclovir (GCV) and/or 5-FC, the cell growth status was evaluated by methyl thiazolyl tetrazolium assay. Cell cycle changes were detected using flow cytometry. In nude mice bearing human gastric cancer, the recombinant adenovirus vector was injected directly into the tumor followed by an intraperitoneal injection of GCV and/or 5-FC. The subsequent tumor growth was then observed. The GFP gene driven by survivin could be expressed within the gastric cancer line SCG7901, but not in normal gastric epithelial cells. RT-PCR demonstrated the presence of the CD/TK gene product in the infected SCG7901 cells, but not in the infected normal gastric epithelial cells. The infected gastric cancer SCG7901, but not the gastric cells, was highly sensitive to the pro-drugs. The CD/TK fusion gene system showed significantly greater efficiency than either of the single suicide genes in killing the target cells (P<0.01). Treatment of the infected cells with the pro-drugs resulted in increased cell percentage in G0-Gl phase and decreased percentage in S phase. In nude mice bearing SCG7901 cells, treatment with the double suicide gene system significantly inhibited tumor growth, showing much stronger effects than either of the single suicide genes (P<0.01). The adenovirus-mediated CD/TK double suicide gene driven by survivin promoter combined with GCV an 5-FC treatment could be an effective therapy against experimental gastric cancer with much greater efficacy than the single suicide gene CD/TK combined with GCV or 5-FC.

• Journal of Nutrition and Health
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• v.12 no.2
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• pp.87-93
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• 1979

인구적 증가와 사료 가격의 상승으로 인한 육류 제품의 가격이 상승하고 있음은 우리나라를 비롯하여 세계적인 현황이다. 이 문제에 대처하는 한 방법으로 새로운 단백질 급원으로써 Single Cell Protein이 개발되었고 이에 대한 여러가지 연구가 되어지고 있다. Single Cell Protein이 인간에게 식용이 될 동물이나 나아가서는 인간에게 직접 식품으로 사용되기 전에 인체나 동물 체내에 끼칠 영향과 그 안전성을 확인하려는 하나의 노력으로 이 연구가 시도되었다. 동물 체내 대사에 미치는 SCP의 악영향의 주원인은 함유된 독성물질로 보고 그 독성물질이 SCP 생산 및 처리 과정 중 어느 시기에 생겨나는가를 규명해 보고자 하였다. Fermentation을 끝낸 SCP의 Supernatant내에 함유된 Inorganic phosphate(I.P.)의 함량을 측정하여 SCP세포의 Viability를 알아보았다. Fermentation을 끝낸 후 10일까지는 I.P.가 차츰줄다가 40일이 지났을 때에는 I.P.의 증가를 보였으나 직후보다는 낮음을 나타냈다. 또한 냉동 건조시킨 뒤에도 SCP Cell이 살아있음을 보였다. 또한 위와 관련지어서 SCP를 Protein급원으로 써서 사육한 흰쥐에 나타난 Protein Efficiency Ratio(PER)를 통하며 SCP의 질을 평가하였다. 실험결과로 나타난 것을 보면 표준 식이에 사용된 Casein의 PER$(\overline{X}=2.58)$이 SCP의 PER$(Dict 1;\overline{X}=0.888$, $Dict 2;\overline{X}=0.893$, $Dict 3;\overline{X}=0.860)$ 보다 유의적으로 높았다. 그리고 총실험기간의 평균치를 볼 때, Fermentation을 끝내고 3일 후와 6일 후에 냉동 건조시킨 SCP의 PER은 시판되는 SCP의 것과 별다른 차이를 보이지 않았다. 그리나 후반기에 있어서는 Fermentation을 끝내고 3일과 6일 후에 냉동 건조시킨 SCP의 PER이 시판되는 SCP의 것보다 약간 저조함을 보였다. 그리고 Casein의 PER은 총 사육기간은 통하여 별 변동이 없음에 반하여 후반기에 SCP의 PER이 급격한 저하를 보임은 SCP 사용상의 문제점을 나타낸 것으로 해석 된다.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.1-7
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• 2016

In the present study, our aim was to determine whether green tea extract (GTE) and its major constituent, epigallocatechin-3-gallate (EGCG) have a protective effect on ethanol-induced cytotoxicity and DNA damage in NIH/3T3 and HepG2 cells. The cell viability and DNA single strand breaks were examined by MTT assay and alkaline single cell gel electrophoresis (Comet assay), respectively. Ethanol decreased the cell viability and also increased DNA single strand breaks in a concentration-dependent manner. On the other hand, GTE showed the protective effect of cytotoxicity and DNA damage induced by ethanol in both cell lines. GTE and EGCG, were found to possess the anti-oxidative and anti-genotoxic activities by evaluation with DPPH test, LDL oxidation assay, oxidative DNA damage assay and 8OH-2'dG generation test. These results were also verified by the experimental results demonstrating the lower cytotoxicity and genotoxicity of commercial green tea liqueur compared to pure ethanol in same concentration. Thus it is concluded that the supplementation of GTE or EGCG may mitigate the ethanol-induced cytotoxicity and DNA damage.

• Molecules and Cells
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• v.39 no.9
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• pp.692-698
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• 2016

Advances in next generation sequencing (NGS) technologies have enabled population-level studies for many animals to unravel the relationships between genotypic differences and traits of specific populations. The objective of this study was to perform evolutionary analysis of single nucleotide polymorphisms (SNP) in genes of Korean native cattle Hanwoo in comparison to SNP data from four other cattle breeds (Jersey, Simmental, Angus, and Holstein) and four related species (pig, horse, human, and mouse) obtained from public databases through NGS-based resequencing. We analyzed population structures and differentiation levels for the five cattle breeds and estimated species-specific SNPs with their origins and phylogenetic relationships among species. In addition, we identified Hanwoo-specific genes and proteins, and determined distinct changes in protein-protein interactions among five species (cattle, pig, horse, human, mouse) in the STRING network database by additionally considering indirect protein interactions. We found that the Hanwoo population was clearly different from the other four cattle populations. There were Hanwoo-specific genes related to its meat trait. Protein interaction rewiring analysis also confirmed that there were Hanwoo-specific protein-protein interactions that might have contributed to its unique meat quality.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2895-2900
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• 2014

We fabricated quantum dot-sensitized solar cells (QDSSCs) using cadmium sulfide (CdS) and cadmium telluride (CdTe) quantum dots (QDs) as sensitizers. A spin coated $TiO_2$ nanoparticle (NP) film on tin-doped indium oxide glass and sputtered Au on fluorine-doped tin oxide glass were used as photo-anode and counter electrode, respectively. CdS QDs were deposited onto the mesoporous $TiO_2$ layer by a successive ionic layer adsorption and reaction method. Pre-synthesized CdTe QDs were deposited onto a layer of CdS QDs using a direct adsorption technique. CdS/CdTe QDSSCs had high light harvesting ability compared with CdS or CdTe QDSSCs. QDSSCs incorporating single-walled carbon nanotubes (SWNTs), sprayed onto the substrate before deposition of the next layer or mixed with $TiO_2$ NPs, mostly exhibited enhanced photo cell efficiency compared with the pristine cell. In particular, a maximum rate increase of 24% was obtained with the solar cell containing a $TiO_2$ layer mixed with SWNTs.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.117-127
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• 2001

The high-level expression of a human single chain urokinase-type plasminogen activator (scu-PA) was achieved by employing a methotrexate (MTX)-dependent gene amplification system in Chinese hamster ovary (CHO) cells. By cotransfecting and coamplifying a scu-PA expression plasmid and dihydrofolate reductase (DHFR) minigene, several scu-PA expressing CHO cell lines were selected and gene-amplified. These recombinant cell lines, NGpUKs, secreted a completely processed scu-PA of 54 kD and up to 60mg/L was accumulated in the culture medium when they were adapted to an optimal MTX concentration. Over 95% of the scu-PA expressed was secreted in the culture medium and identified having the proper function of a plasminogen activator when activated by plasmin. Based on a genomic Southern analysis, a representative subclone, MGpUK-5, exhibited MTX-dependent scu-PA gene amplification, plus the initial single-copy gene of scu-PA eventually turned into about 150 copies of the amplified gene of scu-PA after gradual adaptation to 2.0$\mu$M of MTX. Meanwhile, the transcripts kof the scu-PA gene increased, although -early saturation of transcription was identified at 0.1$\mu$M of MTX. The scu-PA production by the MGpUK-5 subclone also increased relative to the gene amplification and increased transcripts, however, the relationship was not linearly proportional. Accordingly, since the MGpUK cell lines expressed elevated levels of enzymatically active scu-PA, these cell lines could be applied to the largescale production of scu-PA.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.6
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• pp.246-251
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• 2014

Recent studies have shown methods of improving solar cell efficiency. Especially on single crystalline silicon wafer which is high-efficiency solar cell material that has been widely studied. Interstitial oxygen (Oi) is the main impurity in the Czochralski (Cz) growing method, and excess of this can form precipitates during cell fabrication. We have demonstrated the effect of Oi impurity and oxygen precipitation concentration of the wafer on Cz-silicon solar cell efficiency. The result showed a decrease in cell efficiency as Oi and oxygen precipitation increase. Moreover, we have found that the critical point of [Oi] to bring higher cell efficiency is at 14.5 ppma in non-existent Bulk Micro Defect (BMD).

• Clinical and Experimental Reproductive Medicine
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• v.41 no.2
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• pp.68-74
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• 2014

Objective: In search of an ideal method of assisted hatching (AH), we compared the effects of conventional micropipette-AH and laser-AH on the blastocyst formation rate (BFR) and blastocyst cell numbers. Methods: Four-to five-week-old ICR female mice were paired with male mice after superovulation using Pregnant mare's serum gonadotropin (PMSG) and hCG. The two-cell embryos were flushed from the oviducts of female mice. The retrieved two-cell embryos underwent one of five AH procedures: single mechanical assisted hatching (sMAH); cross mechanical assisted hatching (cMAH); single laser assisted hatching (sLAH); quarter laser assisted hatching (qLAH); and quarter laser zona thinning assisted hatching (qLZT-AH). After 72 hours incubation, double immunofluorescence staining was performed. Results: Following a 72 hours incubation, a higher hatching BFR was observed in the control, sMAH, cMAH, and sLAH groups, compared to those in the qLAH and qLZT-AH groups (p<0.05). The hatched BFR was significantly higher in the qLAH and qLZT-AH groups than in the others (p<0.05 for each group). The inner cell mass (ICM) was higher in the control and sMAH group (p<0.05). The trophectoderm cell number was higher in the cMAH and qLAH groups (p<0.05). Conclusion: Our results showed that the hatched BFR was higher in groups exposed the the qLAH and qLZT-AH methods compared to groups exposed to other AH methods. In the qLAH group, although the total cell number was significantly higher than in controls, the ICM ratio was significantly lower in than controls.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.122-126
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• 2020

In this study, we produced the micropatterned channel system using polydimethylsiloxane (PDMS) and micromolding in capillaries (MIMIC) technology and evaluated cellular polarity signals through high-resolved imaging at the single-cell level. In cells treated with platelet-derived growth factor (PDGF), three types of key signals in cell migration; phosphoinositide 3-kinase (PI3 K), Rac, and Actin, were strongly activated in the front area compared to the rear region, whereas myosin light chain (MLC) showed no notable activity in the front and rear areas. Our results will, therefore, provide important information and methodology for studying the correlation between cell polarity signals and cell migration under the newly defined microenvironment.