• Journal of Industrial Technology
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• v.39 no.1
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• pp.7-14
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• 2019

Carbon nanotubes (CNT) on metal substrates are definitely beneficial because they can maintain robust mechanical stability and high conductivity between CNT and metal interfaces. Here, we report direct growth of CNT on Ni-based superalloy, Inconel 600, using thermal chemical vapor deposition (CVD) with acetylene feedstock in the growth temperature range of $400-725^{\circ}C$. Furthermore, we studied the effect of substrate pretreatment on the growth yield enhancement and growth temperature decrease of CNT on Inconel 600. Activation energy (AE) for CNT growth was estimated from the CNT height change with respect to the growth temperature. The AE values significantly decreased from 205.03 to 24.35 kJ/mol by the pretreatment of thermal oxidation of Inconel substrate at $725^{\circ}C$ under ambient. Higher oxidation temperature tends to have lower activation energy. The results have shown the importance of pretreatment temperature on CNT growth yield and growth temperature decrease.

• BMB Reports
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• v.49 no.10
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• pp.566-571
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• 2016

Forskolin (FSK), an adenylyl cyclase activator, has recently been shown to enhance nucleotide excision repair (NER) upon UV exposure. However, our study revealed that this effect was detected in human skin epithelial ARPE19 cells only in growing cells, but not in non-cycling cells. When the cells were grown at low density (70% confluence), FSK was capable of stimulating cAMP responsive element binding (CREB) phosphorylation, a marker for FSK-stimulated PKA activation, and resulted in a significant increase of NER activity compared to control treatment. However, cells grown under 100% confluent conditions showed neither FSK-induced CREB phosphorylation nor the resulting NER enhancement. These findings indicate that cellular growth is critical for FSK-induced NER enhancement and suggest that cellular growth conditions should be considered as a variable while evaluating a reagent's pharmacotherapeutic efficacy.

• Journal of Microbiology and Biotechnology
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• v.23 no.4
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• pp.539-544
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• 2013

The effects of culture depth (2-10 cm) and cell density on the growth rate and biomass productivity of Chlorella sp. XQ-200419 were investigated through the use of a self-designed open circular pond photobioreactor-imitation system. With increases in culture depths from 2 to 10 cm, the growth rate decreased significantly from 1.08 /d to 0.39 /d. However, the biomass productivity only increased slightly from 8.41 to 11.22 $g/m^2/d$. The biomass productivity (11.08 $g/m^2/d$) achieved in 4 cm culture with an initial $OD_{540}$ of 0.95 was similar to that achieved in 10 cm culture with an initial $OD_{540}$ of 0.5. In addition, the duration of maximal areal productivity at a 4 cm depth was prolonged from 1 to 4 days, a finding that was also similar to that of the culture at a 10 cm depth. In both cases, the initial areal biomass densities were identical. Based on these results and previous studies, it can be concluded that the influence of culture depth and cell density on areal biomass productivity is actually due to different areal biomass densities. Under suitable conditions, there are a range of optimal biomass densities, and areal biomass productivity reaches its maximum when the biomass density is within these optimal ranges. Otherwise, biomass productivity will decrease. Therefore, a key factor for high biomass productivity is to maintain an optimal biomass density.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.6
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• pp.240-243
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• 2006

The significant color enhancement in low quality Australian natural sapphire has been achieved by a hydrothermal method. The optimal conditions for the color enhancement of Australian natural sapphire were as follows; hydrothermal reaction temperature: $320{\sim}350^{\circ}C$, duration : 3 days, hydrothermal solvent: 2 M NaOH solution. After the hydrothermal treatment, Australian natural sapphires of transparent colors were obtained, and their grades were found to be improved from commercial to middle/top grade by value chart analysis.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.183-189
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• 1998

A new computer simulation method for film growth, the kinetic Monte Carlo simulation in combination with the results obtained from molecular dynamics simulation for the transient process induced by deposited atoms, was developed. The behavior of energetic atom in Au/Au(100) thin film deposition was investigated by the method. The atomistic mechanism of energetic atom deposition that led to the smoothness enhancement and the relationship between the role of transient process and film growth mechanism were discussed. We found that energetic atoms cannot affect the film growth mode in layer-by-layer at high temperature. However, at temperature of film growth in 3-dimensional mode and in quasi-two-dimensional mode, energetic atoms can enhance the smoothness of film surface. The enhancement of smoothness is caused by the transient mobility of energetic atoms and the suppression for the formation of 3-dimensional islands.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.5
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• pp.332-336
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• 2001

When parental Chinese hamster ovary (CHO) cell clones that are capable of producing thrombopoietin (TPO) were subjected to high methotrexate (MTX) concentrations, clonal variations in cell growth were apparent. In the clones that had no significant enhancement in specific TPO productivity (q$\_$Tpo/)when a higher level of MTX was administered, their growth was not depressed significantly nor their cell size changed significantly. On the other hand, those clones that showed a significant-enhancement in q$\_$Tpo/ at higher a MTX dosage, cell growth was depressed initially but recovered during successive sub-cultures. Furthermore, their cell size increased, which suggested that changes in cell size may be indicative of an enhanced q$\_$Tpo/. When the enhancement of the q$\_$Tpo/ of 9 clones after a high MTX dosage was plotted against the extent of the increase of their size, there was a linear correlation (γ$^2$=0.80, p<0.001, ANOVA), which suggested that an enhancement of q$\_$Tpo/ after high MTX administration can be measured by the increase in their cell size. Taken together, our data demonstrate that the selection of amplified CHO cell clones with enhanced q$\_$Tpo/ can be done upon their increased size and growth pattern. This facilitates the development of highly productive recombinant CHO cell lines.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.2
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• pp.73-77
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• 2004

The color enhancement for natural Zambian amethyst of low quality was carried out by the hydrothermal treatment method. The hydrothermal treatment conditions were as follows: reaction temperature; $300^{\circ}C$, duration; 30 hrs, filling; 40%, solvent; 6 M-HCI solution. The reddish purple amethyst of high quality was obtained under these conditions. From the result of ICP/AES, it was known that color enhancement was affected by a Fe elemental content to exist in the inside of natural Zambian amethyst. Also, from the result of UY-VIS-NIR, it was shown that the absorption peak at 550 nm after hydrothermal treatment is slightly lower than those of non-treated natural Zambian amethyst. In this study, it was known that hydrothermal treatment method was a way to suitable for increase of commercial value of natural Zambian amethyst.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.17-24
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• 2001

A model for quantifying the effect of steam pressure on the oxide thickness growth was developed based on the experimental data available. First, empirical equations for the thickness estimation of oxide formed in 1 atm steam were made. The oxide growth kinetics turned out to be dependent on 0.4th power of oxidation time. With an assumption that the transition oxide thickness be only a function of temperature, a model for the enhancement of steam pressure on oxide growth was developed. The enhancement coefficient for steam pressure is calculated to be 0.01~0.013 $bar^{-}$. The developed model generally well explains the experimental data.a.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.51-54
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• 1998

It has been proved that co-cultivation of human neroblastoma cells and human fibroblast cells can enhance nerve cell growth and the production of BDNF in perfusion cultivation. In batch co-cultivation, maximum cell density was increased up to 1.76${\times}$106 viable cells/mL from 9${\times}$105 viable cells/mL of only neuroblastoma cell culture. The growth of neuroblastoma cells was greatly improved by culturing both nerve and fibroblast cells in a perfusion process, maintaining 1.5${\times}$106 viable cells/mL, which was much higher than that form fed-batch cultivation. The nerve cell growth was greatly enhance in both fed-batch and perfusion cultivations while the growth of fibroblast cells was not. It strongly implies that the factors secreted from human fibrobast cells and/or the environments of co-culture system can enhance both cell growth and BDNF secretion. Specific BDNF production rate was not enhanced in co-cultures; however, the production period was increased as the cell growth was lengthened in the co-culture case. Competitive growth between nerve cells and fibroblast cells was not observed in all cases, showing no changes of fibroblast cell growth and only enhancement of the neuroblastoma cell growth and overall BDNF production. It was also found that the perfusion cultivation was the most appropriate process for cultivating two cell lines simultaneously in a bioreactor.

• Journal of Acupuncture Research
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• v.30 no.1
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• pp.57-70
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• 2013

This study was to investigated the effects of the bee venom on inhibition of cell growth via upregulation of death receptor expression in the A549 human lung cancer cells. Bee venom(1-5 ${\mu}g$/ml) inhibited the growth of A549 lung cancer cells by the induction of apoptotic cell death in a dose dependent manner. Consistent with apoptotic cell death, expression of TNFR1, Fas, death receptors(DR) 3, 4 and 6 was increased in the cells. Expression of DR downstream pro-apoptotic proteins including caspase-3, -9 and Bax was concomitantly increased, but the expression of Bcl-2, NF-${\kappa}B$ were inhibited by treatment with bee venom in A549 cells. Moreover, deletion of DR3, DR4 by small interfering RNA significantly reversed bee venom-induced cell growth inhibitory effect, whereas Apo3L strengthened anti-proliferative effect of bee venom through enhancement of DR3 expression. These results suggest that bee venom should exert anti-tumor effect through induction of apoptotic cell death in lung cancer cells via enhancement of death receptor expression, and that bee venom could be a promising agent for preventing and treating lung cancer.