• Proceedings of the Korean Fiber Society Conference
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.171-174
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• 2001

초임계유체(supercritical fluid, SCF)는 친환경적 용매로서 고분자 합성과 기능화를 비롯하여 RESS(rapid expansion of supercritical solution)와 초임계염색 등의 섬유공정 분야에서 연구자들의 흥미로운 관심을 받아 오고 있다. 초임계유체는 기체와 액체의 중간적인 특성을 가지면서도 가스와 같이 우수한 확산력을 가지며 또한 아주 낮은 점도를 갖는다. SCF 중에서 비교적 온화한 조건(31.1℃의 임계온도, 73.8기압의 임계압력, Figure 1)에서 초임계상태를 가질 수 있는 이산화탄소가 가장 많이 이용되고 있는데 이는 자원이 풍부하며 쉽게 회수하여 사용할 수 있어 응용 면에서 유리하다. (중략)

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.22-26
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• 1991

Potential energy surfaces for the proton transfer in a formamide dimer have been obtained by ab initio SCF calculations with STO-3G, 3-21G, and 4-31G basis sets and several features have been discussed. Energy minima for a formamide dimer and its tautomer are varied with basis sets. But the general features of the potential energy surfaces are similar among them.

• Bulletin of the Korean Chemical Society
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• 제7권3호
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• pp.218-224
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• 1986

The electronic structures of silane and chlorosilanes are studied by the SCF calculations using effective core potentials (ECP's). The results obtained with ECP's are in good agreement with corresponding all electron calculations demonstrating the reliability of ECP employed. The importance of polarization functions for the second row atoms is also evident in this study. The SCF calculations of silane and chlorosilanes are useful in qualitative understanding of many chemical properties since many trends are correctly obtained with the polarization functions included in basis sets of reasonable size.

• KOREAN POULTRY JOURNAL
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• 제39권4호통권450호
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• pp.118-122
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• 2007

• KOREAN POULTRY JOURNAL
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• 제54권11호
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• pp.124-127
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• 2022

• IMMUNE NETWORK
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• 제10권1호
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• pp.15-25
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• 2010

Background: Rat mast cells were regarded as a good model for mast cell function in immune response. Methods: Rat bone marrow mast cells (BMMC) were prepared both by recombinant rat IL-3 (rrIL-3) and by recombinant mouse stem cell factor (rmSCF), and investigated for both proliferation and differentiation in time course. Rat BMMC was induced by culture of rat bone marrow cells (BMCs) in the presence of both rrIL-3 (5 ng/ml) and rmSCF (5 ng/ml). Culture media were changed 2 times per week with the cell number condition of $5{\times}10^4/ml$ in 6 well plate. Proliferation was analyzed by cell number and cell counting kit-8 (CCK-8) and differentiation was by rat mast cell protease (RMCP) II and histamine. Results: Cell proliferation rates reached a maximum at 8 or 11 days of culture and decreased thereafter. However, both RMCP II production and histamine synthesis peaked after 11 days of culture. By real time RT-PCR, the level of histidine decarboxylase mRNA was more than 500 times higher on culture day 11 than on culture day 5. By transmission electron microscopy, the cells were heterogeneous in size and contained cytoplasmic granules. Using gated flow cytometry, we showed that cultured BMCs expressed high levels of $Fc{\varepsilon}RI$ and the mast cell antigen, ganglioside, on culture day 11. Conclusion: These results indicate that rat BMMCs were generated by culturing BMCs in the presence of rrII-3 and rmSCF and that the BMMCs have the characteristics of mucosal mast cells.

• Molecules and Cells
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• 제41권11호
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• pp.971-978
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• 2018

The stem cell factor (SCF)/c-KIT axis plays an important role in the hematopoietic differentiation of human pluripotent stem cells (hPSCs), but its regulatory mechanisms involving microRNAs (miRs) are not fully elucidated. Here, we demonstrated that supplementation with SCF increases the hematopoietic differentiation of hPSCs via the interaction with its receptor tyrosine kinase c-KIT, which is modulated by miR-221 and miR-222. c-KIT is comparably expressed in undifferentiated human embryonic and induced pluripotent stem cells. The inhibition of SCF signaling via treatment with a c-KIT antagonist (imatinib) during hPSC-derived hematopoiesis resulted in reductions in the yield and multi-lineage potential of hematopoietic progenitors. We found that the transcript levels of miR-221 and miR-222 targeting c-KIT were significantly lower in the pluripotent state than they were in terminally differentiated somatic cells. Furthermore, suppression of miR-221 and miR-222 in undifferentiated hPSC cultures induced more hematopoiesis by increasing c-KIT expression. Collectively, our data implied that the modulation of c-KIT by miRs may provide further potential strategies to expedite the generation of functional blood cells for therapeutic approaches and the study of the cellular machinery related to hematologic malignant diseases such as leukemia.

• Korean Journal of Materials Research
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• 제9권7호
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• pp.695-700
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• 1999

Effects of two-step aging treatment on the stress corrosion cracking(SCC) resistance of 7050 Al alloy were investigated by transmission electron microscopy, electrical conductivity measurement and stress corrosion facter(SCF) evaluation. It was found that η', principal hardening phase, transformed to η during over aging above maximum hardness, and SCC resistance was improved by increasing of the size and interspacing of η particles in matrix and grain boundary. The electrical conductivity increased with aging time, but SCF decreased due to the decrease of yield strength. This results mean increase of SCC resistance The optimum two-step aging condition in forged 7050 Al alloy was to be first aged at $120^{\circ}C$ for 6h and then finally aged at $175^{\circ}C$ for 12h.

• Journal of the Korean Chemical Society
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• 제22권4호
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• pp.239-244
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• 1978

Spectroscopic studies of trans-1,2-bispyrazylethylene (BPE), one of the stilbene analogues, were carried out. In normal UV spectra, a distinct $n{\rightarrow}{\pi}^*$ absorption band is missing because of a strong, nearly isoenergetic ${\pi}{\rightarrow}{\pi}^*$ absorption band. The second derivative and low temperature $(77^{\circ}K)$ UV absorption spectra were taken and $n{\rightarrow}{\pi}^*$ absorption band was identified by these methods. The transition energies of ${\pi}{\rightarrow}{\pi}^*$ transitions were calculated by Pariser-Parr-Pople (PPP)-SCF-CI MO method. The calculated values showed good agreement with the observed spectral data. Luminescence studies were also carried out at low temperature. From the fluorescence spectra, fluorescence polarization studies, and PPP-SCF-CI MO calculation, the fluorescent state was determined to be a singlet $({\pi},\;{\pi}^*)$ state. This conclusion is in good agreement with the results obtained from alkaline salt effects on the fluorescence of this compound.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.770-775
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• 2000

Several process parameters were studied to ascertain the effect on degradation of sugar cane bagasse in relation to the production of cellulase enzyme and reducing sugars by Solid Substrate Fermentation (SSF) and Submerged Culture Fermentation (SCF) of Aspergillus terreus SUK-1. The effect of air-flow rate (0-1.3 v/v/m), of different ratios of substrate weight to liquid volume (1:6, 1:10, 1:20, and 1:30 w/v, g/ml), scale-up effect (10, 20, and 100 times of 1:10 ration, w/v) and the effect of temperature (30, 40, 50, and $60^{\circ}C$) in SSF were studied. Air-flow rate of 1.0 v/v/m gave the highest enzyme activity (FPase 0.25 IU/ml, CMCase 1.24 IU/ml) and reducing sugars concentration (0.72 mg/ml). Experiment using 1:10 ratio (w/v) was found to support maximum cellulase activity (FPase 0.58 IU/ml, CMCase 1.97 IU/ml) and reducing sugar concentration (1.23 mg/ml). Scaling-up the ratio of 1:10(w/v) by a factor of 20 gave the highest cellulase activity (FPase 0.71 IU/ml, CMCase 2.25 IU/ml) and reducing sugar concentration (3.67 mg/ml). The optimum temperature for cellulase activity and reducing sugar production was $50^{\circ}C$(FPase 0.792 IU/ml, CMCase 2.25 IU/ml and 3.85 mg/ml for reducing sugar concentration). For SCF, the activity of cellulase enzyme and reducing sugar concentration was found to be lower than that obtained for SSF. The highest cellulase activity obtained in SCF was 50% lower than the highest cellulase activity in SSF, while for reducing sugar concentration, the highest concentration obtained in SCF was 90% lower than that obtained in SSF.