• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.243-248
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• 2004

Production of (R)-3-hydroxybutyric acid (R3HB) by fed-batch culture and continuous culture of metabolically engineered Escherichia coli harboring Ralstonia eutropha PHB biosynthesis and depolymerase genes was examined in a 30 1 pilot-scale fermentor. A new stable two-plasmid system, pBRRed containing the R. eutropha PHB depolymerase gene and pMCS 105 containing the R. eutropha PHB biosynthesis genes, was developed. Among a variety of E. coli strains harboring plasmids, recombinant E. coli XL-10 Gold (pBRRed, pMCS105) was able to produce R3HB with the highest efficiency in a batch culture. By the fed-batch culture of recombinant E. coli XL-10 Gold(pBRRed, pMCS 105) in a 30 1 fer-mentor, the final R3HB concentration was 22.4 g/l giving a productivity of 0.97 g/l-h. To produce R3HB to a high concentration with high productivity, a new strategy of fed-batch culture followed by a continuous culture was investigated. The maximum productivity and R3HB concentration were 5.06 g/l-h and 25.3 g/l, respectively. These results show that economical production of R3HB is possible by recombinant E. coli in large scale.

• KSBB Journal
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• v.14 no.3
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• pp.284-290
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• 1999

Glucose fed-batch culture was studied to improve cellulose productivity by Acetobacter xylinum BRC5. When initial glucose concentrations in batch cultures were less than 20 g/L, yield coefficients of cellulose (Yp/s) remained a constant value of 0.21 g cellulose/g glucose. But a low yield coefficient, Yp/s=0.13 was obtained from an initial glucose concentration of 40 g/L. Since initial high glucose concentrations in batch culture resulted in low yields of cellulose, constant fed-batch cultures were carried out. The optimal feed rate for fed-batch culture was 2.22 g glucose/L.h. In constant fed-batch culture without DO control, 10 g/L of cellulose was obtained from 40 g/L of glucose with this feed rate, which was approximately two fold higher than that of the batch culture with the same initial glucose concentration. In DO stat plus fed-batch culture, the highest cellulose productivity could be obtained when dissolved oxygen level was controlled at 10% of air saturation, and cellulose productivity increased about 1.5 times compared with that of the culture without DO control.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.116-121
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• 2012

Cordyceps and its allies fungi has been described as a secret medicine that gives eternal youth and a long life. Some species of Cordyceps are sources of biochemicals, such ascordycepin, with interesting biological and pharmacological properties. Hence, it has been studied to uncover its pharmacological effect. We attempted to study the formation of fruiting bodies and to develop means of mass production Korean isolate of Paecilomyces tenuipes has been inoculated into silkworms, where it reproduced using culture container, mini-kit successfully. Culture container, mini-kit is composed of a cylinder-shaped body and lid. The container is made of translucent polyethylene terephthalate. The size of the container is $82{\times}75mm$, reduced by 10 times as compared with the conventional culture kit. The mini kit has many advantages - high culture amount, ability of maintaining optimal humidity, parasite-free cultivation and high-end appearance. With the kit, the optimal cultivation condition is under $22^{\circ}C$, culture period of 53 days. And synnemata of P. tenuipes could be kept fresh for 14 days at the temperature of under $10^{\circ}C$. Therefore, the Min-kit can be used in both ways as a culture container and a packing kit for end-user customers.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.791-800
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• 2023

This study was conducted to lay the foundation for creating a society safe from radiation by investigating the establishment of a radiation social safety net and the establishment of safety awareness and safety culture among citizens living in Busan. Data was collected through an online survey, and 200 copies of the survey were analyzed. Data were analyzed using SPSS Window Ver 28.0. To verify differences between groups, t-test and one way ANOVA were performed, and correlation analysis was performed to confirm the relationship between variables. In addition, multiple linear regression analysis was conducted to confirm the influence between variables. As a result, first, in terms of building a social safety net, citizens' safety awareness, and establishing a safety culture, the scores of the group with male gender, age in 20s, and high school graduation were found to be high. Among them, there was a statistical difference in gender at the significance level of .01 for building a social safety network and at the significance level of .05 for establishing a safety culture. In terms of occupation, there was a statistical difference between professionals and service workers at the significance level of .05 regarding the building of a radiation social safety network. Second, as a result of multiple regression analysis, it was found that 'local government radiation safety education', a subordinate factor in building a radiation social safety network, had a positive effect on citizens' safety awareness and establishment of a safety culture. Third, the results of the correlation analysis between the building of a social safety network, citizens' safety awareness, and establishment of a safety culture showed a positive correlation. Therefore, it is believed that a good radiation social safety network will have a positive impact on citizens' safety awareness and the establishment of a safety culture.

• Journal of Korean Academy of Nursing Administration
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• v.8 no.4
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• pp.551-561
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• 2002

Purpose : The purpose of the present study was to examine the causal relationships among head nurses' leadership (consideration oriented leadership, structure initiated leadership), nursing unit culture (human development culture, task development culture), and nurses' organizational commitment. Method : Four large general hospitals located in and around Seoul were selected to participate. The total sample of 286 registered nurses represents a response rate of 90 percent. Data for this study was collected from August to September in 2000 by questionnaire. Path analyses with LISREL program were used to test the fit of the proposed model to the data and to examine the causal relationships among variables. Result : Both the proposed model and the modified model fit the data adequately. The model revealed relatively high explanatory power. 52% of human development culture was explained by predicted variables and 44% of task development was explained by predicted variables; 47% of the organizational commitment was explained by predicted variables. In predicting developmental (both human and task) nursing unit culture, the findings of this study clearly demonstrated that head nurses' consideration oriented leadership might be the most important variable. The result also showed that head nurses' consideration oriented leadership might be the most important variable among the predicted variables in predicting organizational commitment. Conclusion : Based on the findings of this study, it was suggested that various studies, for example, matching leadership and nursing unit culture, were needed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.564-570
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• 2005

In the present study, the protective effects of Bcl-2 over-expression in a suspension culture (without any adaptation) and spent medium (low nutrient and high toxic metabolite conditions) were investigated. In the suspension culture without prior adaptation, the viability of the control cell line fall to 0% by day 7, whereas the Bcl-2 cell line had a viability of 65%. The difference in the viability and viable cell density between the Bcl-2 and control cell lines was more apparent in the suspension culture than the static culture, and became even more apparent on day 6. Fluorescence microscopic counting revealed that the major mechanism of cell death in the control cell line in both the static and suspension cultures was apoptosis. For the Bcl-2 cell lines, necrosis was the major mode of cell death in the static culture, but apoptosis became equally important in the suspension culture. When the NS0 6A1 cell line was cultured in spent medium taken from a 14 day batch culture, the control cell line almost completely lost its viability by day 5, whereas, the Bcl-2 still had a viability of 73%. The viable cell density and viability of the Bcl-2 cell line cultivated in fresh medium were 2.2 and 2.7 fold higher, respectively, than those of the control cultures. However, the viable cell density and viability of the Bcl-2 cultivated in the spent medium were 8.7 and 7.8 fold higher, respectively, than those of the control cultures. Most of the dead cells in the control cell line were apoptotic; whereas, the major cell death mechanisms in the Bcl-2 cell line were necrotic.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.607-619
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• 2015

This paper investigates the relationships among family-friendly culture, intrinsic motivation, team-member exchange(TMX), and creativity in ICT(information & communication technology) company. Also the study investigates the moderator effect of TMX and the mediator effect of intrinsic motivation in the relationships between family-friendly culture and creativity. A structural equation modeling(SEM) was employed to test the hypotheses. Using survey data collected from 229 R&D department and support personnel in ICT company. The main finding of this study was as follows: First, a family-friendly culture had a negative effect on employee creativity. Second, intrinsic motivation had a positive impact on employee creativity. Third, a family-friendly culture had a positive effect on intrinsic motivation. Fourth, intrinsic motivation mediated effect on the relationship between a family-friendly culture and employee creativity. Fifth, the positive relationships between a family-friendly culture and intrinsic motivation were stronger when TMX was high rather than low. In particular, this review concludes with implications for future research, limitations of this study, and practical application.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.221-228
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• 2014

Despite that porcine spermatogonial stem cells (pSSCs) have been regarded as a practical tool for preserving eternally genetic backgrounds derived from pigs with high performance in the economic traits or phenotypes of specific human diseases, there were no reports about precise definition of niche conditions promoting proliferation and maintenance of pSSCs. Accordingly, we tried to determine niche conditions supporting proliferation and maintenance of undifferentiated pSSCs for short-term. For these, undifferentiated pSSCs were progressively cultured in different composition of culture medium, seeding density of pSSCs, type of feeder cells and concentration of growth factors, and then total number of and alkaline phosphatase (AP) activity of pSSCs were investigated at post-6 day culture. As the results, the culture of $4{\times}10^5$ pSSCs on mitotically in activated $2{\times}10^5$ STO cells in the mouse embryonic stem cell culture medium (mESCCM) supplemented with 30 ng/ml glial cell line-derived neurotrophic factor (GDNF) was identified as the best niche condition supporting effectively the short-term maintenance of undifferentiated pSSCs. Moreover, the optimized short-term culture system will be a basis for developing long-term culture system of pSSCs in the following researches.

• International Area Studies Review
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• v.22 no.1
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• pp.237-257
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• 2018

The distinction between high culture and popular culture is gradually weakening. Taste is becoming a new standard to distinguish culture. This research analyze sports film by taste cultural perspective. In perspective of Universality, and is Both emphasized the individual attitude of sincere effort. This can be interpreted as a capitalist ideology. Analyzing the two films as a global and local tastes culture, shows a new world that follows the birth of a star player and deifies the football beyond borders and races. shows the distrust of the system through the K-League Citizens' Club and the trust in individual who does their best in the meantime.

• Journal of Marine Bioscience and Biotechnology
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• v.16 no.1
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• pp.36-44
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• 2024

This study attempted to improve the growth of the freshwater microalgae, Parachlorella kessleri, through the sequential optimization of culture conditions. This attempt aimed to enhance the microalgae's ability to fixate atmospheric CO₂. Culture temperature and light intensity appropriate for microalgal growth were scanned using a high-throughput photobioreactor system. The supplied air flow rate varied from 0.05 to 0.3 vvm, and its effect on the growth rate of P. kessleri was determined. Next, sodium phosphate buffer was added to the culture medium (BG11) to enhance CO₂ fixation by increasing the availability of CO₂(HCO₃^-) in the culture medium. The results indicated that optimal culture temperature and light intensity were 20℃-25℃ and 300 μE/m²/s, respectively. Growth rates of P. kessleri under various air flow rates highly depended on the increase of the culture's flow rate and pH which determines CO₂ availability. Adding sodium phosphate buffer to BG11 to maintain a constant neutral pH (7.0) improved microalgal growth compared to control conditions (BG11 without sodium phosphate). These results indicate that the CO₂ fixation rate in the air could be enhanced via the sequential optimization of microalgal culture conditions.