• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.10
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• pp.709-716
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• 2022

In this paper the Gamma guidance law, which was used for IUS (Inertial Upper Stage), is applied for solid-motor guidance of a upper stage of a satellite launch vehicle. The RCS (Reaction Control System), which activates after burnout of the upper stage, is employed for the convergence of the guidance algorithm and compensation of velocity errors induced by the solid motor. The algorithm is also simplified by replacing the time-consuming numerical integration process to predict final vehicle states with Keplerian trajectories. The performance of the algorithm is evaluated by conducting 3-DOF computer simulations for off-nominal flight conditions. The numerical results show that Gamma guidance can reduce the orbit injection accuracy in comparison with that obtained by applying open-loop commands.

• Journal of Life Science
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• v.22 no.10
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• pp.1316-1323
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• 2012

The present study was conducted to investigate whether myoblasts can be transdifferentiated into adipocytes by ectopic expression of adipogenic transcription factors, including peroxisome proliferator-activated receptor-${\gamma}$ ($PPAR{\gamma}$), CCAAT/enhancer-binding protein-${\alpha}$ (C/$EBP{\alpha}$), sterol regulatory element binding protein-1c (SREBP1c), and Krueppel-like factor 5 (KLF5), in primary bovine satellite cells. Transcription factors were transiently transfected into primary bovine myoblasts, and the cells were cultured with adipogenic differentiation medium for 2 days and then cultured on growth medium for an additional 8 days. Ectopic expression of $PPAR{\gamma}$ or C/$EBP{\alpha}$ alone was insufficient to induce adipogenesis in myoblasts. However, overexpression of both $PPAR{\gamma}$ and C/$EBP{\alpha}$ in myoblasts was able to induce adipogenic transdifferentiation as indicated by the appearance of mature adipocytes, the induction of adipogenic gene expressions, and the suppression of myogenic gene expressions. In addition, KLF5 and $PPAR{\gamma}$ co-transfected bovine myoblasts were converted to adipocytes but not in cells transfected with only KLF5 expression vector. Overexpression of SREBP1c alone was sufficient to induce transdifferentiation from myoblasts into adipocytes. These results demonstrate that primary bovine satellite cells can be transdifferentiated into adipocytes either by single ectopic expression or combined expression of adipogenic transcription factors in a culture system.

• Korean Journal of Ecology and Environment
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• v.38 no.4 s.114
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• pp.454-460
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• 2005

The goal of this research was to better understand the mechanism of environmental control of PEPC expression from Hydrilla verticillata grown under $CO_2$ stress. When PEPC concentration was plotted against $CO_2$ compensation point (${\Gamma}$), a linear increase in PEPC concentration was seen with a decrease in $CO_2$ compensation point. ${\Gamma}$ was measured on each day of the time course induction. Hydrilla plants exhibited an initially large decrease in ${\Gamma}$ between day 0 and day 1; thereafter, the ${\Gamma}$ declined in a fairly linear trend for the remaining 5 day time course. PEPC activity varied greatly over the time course. PEPC activity increased daily from day 0 through day 5 of the time course. Activity of PEPC increased almost 4-fold over the time course induction. The two upper bands with the approximately 100 kD mass are the PEPC subunits and PEPC was barely detectable in day 0 but increased through day 4 with day 5 being approximately equal to day 4. We provide evidence of increased PEPC protein concentration, and increased PEPC enzyme activity in as little as 24 h after beginning of induction.

• Clinical and Experimental Pediatrics
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• v.46 no.7
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• pp.702-709
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• 2003

Purpose : $IFN{\gamma}$ sentitizes many tumor cells to $TNF{\alpha}$ and FASL-mediated apoptosis by enhancing the expression of TNF or FAS/CD95 receptor and modulating the activation of caspase and Bcl-2 family. It has been reported that $IFN{\gamma}$ and $TNF{\alpha}$ synergistically caused differentiation and growth inhibition of neuroblastoma cells. Even though some neuroblastoma cell express FASR/FASL on the cell surface, they could not induce apoptosis by ligation of the FAS/CD95 receptor. But the treatment of $IFN{\gamma}$ is reported to induce apoptosis in some neuroblastoma cell lines through the CD95/CD95L autocrine circuit. In this study, we examined whether $IFN{\gamma}$ could affect $TNF{\alpha}$ and agonistic FAS/CD95 antibody(CH-11)-induced apoptosis against neuroblastoma cell lines that had shown diverse drug sensitivity and resistance. Methods : CHLA-15, CHLA-90 and LA-N-2 neuroblastoma cells were cultured in IMDM and treated with recombinant $IFN{\gamma}$, $TNF{\alpha}$ and CH-11 antibody. Cell viability was measured by DIMSCAN with a fluorescent calcein-AM. Apoptosis was analyzed through flow cytometry using Annexin V-PE and 7-ADD staining and confirmed by pancaspase and caspase-8 blocking experiments. The expression of TNF RI and FAS/CD95 receptor was evaluated by flow cytometry using the corresponding antibody and PE-conjugated secondary antibody. Results : $IFN{\gamma}$ or $TNF{\alpha}$ alone had no demonstrable cytotoxic effects, whereas both cytokines in combination induced apoptosis synergistically in CHLA-15 and CHLA-90 cells. Although there was no cytotoxicity with the ligation of CH-11 alone in CHLA-90 cells, pretreatment of $IFN{\gamma}$ increased the sensitivity of CH-11-mediated apoptosis. The expression of TNFRI and FAS/CD95R were non-specifically enhanced after treatment of $IFN{\gamma}$ without relation to sensitivity to $TNF{\alpha}$ and CH-11. This finding suggest up-regulation of both receptors may contribute to sensitization of $TNF{\alpha}$ and CH-11-mediated apoptosis by $IFN{\gamma}$ in only sensitive cell lines. Conclusion : $IFN{\gamma}$ induced sensitization of $TNF{\alpha}$ and agonistic FAS/CD95 antibody-mediated apoptosis on some neuroblastoma cells through up-regulation of TNFRI and FAS/CD95 receptor.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.472-477
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• 2004

To study the radiation related gene expression in mutants of Bacillus lentimorbus WJ5 induced by gamm radiation, the simultaneous gene expression was analyzed by DNA micro array. We constructed DNA chips including two thousand randomly digested genome spots of B. lentimorbus WJ5 and compared its quantitative aspect with seven mutants induced by gamma radiation $(^{60}/Co)$. From the cluster analysis of gene expression pattern, totally 408 genes were expressed and 27 genes were significantly upregulated by the gamma radiation in all mutants. Especially, genes involved in repair (mutL, mutM), energy metabolism (acsA, sdhB, pgk, yhjB, citB), protease (npr), and reduction response to oxidative stress (HMM) were simultaneously upregulated. It seems that the induction of the direct and/or indirect repair related genes in mutants induced by gamma radiation could be remarkably different from the adaptive responses against acute exposure to radiation.

• KCID journal
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• v.5 no.1
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• pp.32-46
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• 1998

This study was conducted to derive optimal design floods by generalized gamma distribution model of the annual maximum series at six watersheds along Han and Nag Dong river systems. Design floods obtained by different methods for estimation of parameters

• Journal of Food Hygiene and Safety
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• v.23 no.1
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• pp.1-5
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• 2008

The inhibition of cholesterol autoxidation by commercial ${\gamma}$-Oryzanol (0, 50, 100, and 300 ppm) was studied in an aqueous model system for 20 h at pH 5.5 and $80^{\circ}C$. The inhibition effectiveness of the commercial ${\gamma}$-Oryzanol was followed by the retention of cholesterol and the formation of C-7 oxidized cholesterol derivatives (OCDs). Changes in the amount of ${\gamma}$-Oryzanol in the aqueous system were determined during cholesterol autoxidation. A method to detect the levels of 7-ketocholesterol, $7{\alpha}$-hydroxycholesterol and $7{\beta}$-hydroxycholesterol in an aqueous model system with ${\gamma}$-Oryzanol was developed by using the hexane-ethyl acetate extraction system and high-performance liquid chromatography. Results showed that the levels of C-7 OCDs in an aqueous dispersion containing 300 ppm of ${\gamma}$-Oryzanol were not significantly (p>0.05) increased, when compared to other treatments (0, 50, and 100 ppm), during the accelerated cholesterol oxidation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.59-68
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• 1998

This study was conducted to derive optimal design floods by generalized gamma distribution model of the annual maximum series at eight watersheds along Geum, Yeongsan and Seomjin river systems. Design floods obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model were compared by the relative mean errors and graphical fit along with 95% confidence limits plotted on gamma probability paper. The results were analyzed and summarized as follows. 1. Basic statistics and parameters were calculated by the generalized gamma distribution model using different methods for parameters. 2. Design floods according to the return periods were obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model. 3. It was found that design floods derived by sundry averages method for parameters and Cunnane method for plotting position in the generalized gamma distribution are much closer to those of the observed data in comparison with those obtained by the other methods for parameters and for plotting positions from the viewpoint of relative mean errors. 4. Reliability of design floods derived by sundry averages method in the generalized gamma distribution was acknowledged within 95% confidence interval.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.3
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• pp.83-95
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• 1997

This study was conducted to derive optimal design floods by Gamma distribution models of the annual maximum series at eight watersheds along Geum , Yeong San and Seom Jin river Systems, Design floods obtained by different methods for evaluation of parameters and for plotting positions in the Gamma distribution models were compared by the relative mean errors and graphical fit along with 95% confidence interval plotted on Gamma probability paper. The results were analyzed and summarized as follows. 1.Adequacy for the analysis of flood flow data used in this study was confirmed by the tests of Independence, Homogeneity and detection of Outliers. 2.Basic statistics and parameters were calculated by Gamma distribution models using Methods of Moments and Maximum Likelihood. 3.It was found that design floods derived by the method of maximum likelihood and Hazen plotting position formular of two parameter Gamma distribution are much closer to those of the observed data in comparison with those obtained by other methods for parameters and for plotting positions from the viewpoint of relative mean errors. 4.Reliability of derived design floods by both maximum likelihood and method of moments with two parameter Gamma distribution was acknowledged within 95% confidence interval.

• Proceedings of the Korea Water Resources Association Conference
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• 1998.05a
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• pp.127-132
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• 1998