• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.299-305
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• 1996

This study was conducted to investigate the effects of co-culture for the development rate to morula/blastocyst stages of early porcine embryos, derived from oocytes matured and fertilized in vitro, with porcine oviductal epithelial cell monolayers(POEC) in the two different media, respectively. The rates of embryos developed to 2-, 4-, 8∼16-cell and morula/blastocyst stage were 57.2, 48.2, 37.2 and 19.3% in Ham's F-10 with POEC, and 51.4, 41.2, 31.1, and 15.5% in TCM-HEPES with POEC, respectively. The above development rates to morula/blastocyst stages were significantly higher than those of the embryos cultured in the Ham's F-10 and TCM-HEPES with out POEC(P<0.05). The in vitro development rates to the morula/blastocyst stage of 1-cell embryos cultured in Ham's F-10 and TCM-HEPES without POEC were 1.1∼1.2%. Especially, most of embryos were observed to arrest the development beyond 4-cell stages. As shown in the above results, the co-culture of in vitro produced porcine embryos with POEC in the two different media enhanced the development of fertilized eggs to morula/blastocyst stages in vitro. However, we didn't find out any difference for the in vitro development to morula/blastocyst stages between Ham's F-10 and TCM-HEPES media.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.588-603
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• 2021

This study details a researcher's self-study journey in advancing from a computational thinking (CT) novice to an expert. The researcher went through a four-stage process, with a preliminary literature review preceding the four stages. From the literature review, the computational thinking analysis (CT_AT) tool was developed for use in stage one to analyze science, technology, engineering, art, and mathematic (STEAM) modules. Although no discernable patterns were found in analyzing the five science and five engineering-based modules, the analysis revealed which CT practices were missing or weakly exposed. In stage two activities were suggested to promote these missing or weakly exposed practices. Stage three required the researcher to develop his own STEAM module from the viewpoint of exposing students to CT. The fourth stage was to validate the CT_AT through interviews with pre-service and in-service teachers. These interviews led to changes in the CT_AT tool and, as a result, the researcher produced a guidebook that could be used by teachers in their own CT studies. This guidebook can be used by teachers to develop and become competent in CT skills.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.123-128
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• 1989

Demi-embryos were successfully produced by bisection of ICR mouse embryos at preimplantation stages. They were microsurgically bisected using a microsurgical blade attached to a micromanipulator after pretreatment with 0.5% pronase in PBS for two minutes or not. Embryos with softened zona pellucida were more easily bisected and less damaged than intact embryos. The highest success rate in bisection has been achieved by selecting blastocysts(94.1% in success rate with intact blastocysts and 100% in success rate with zona softened blastocysts). Demi-embryos without zona pellucida were cultured in D-PBS or M-16 medium at $37^{\circ}C$, 5% $CO_2$ in air for 72 hours for 2-cell stage embryos, 48 hours for 4-to 8-cell stage embryos, 24 hours for morula stage embryos and 6~12 hours for blastocyst stage embryos. For the in vitro culture of 2-cell stage embryos, $100{\mu}M$ 2Na-EDTA was added to the media. M-16 medium was better for the in vitro development of mouse embryos than PBS, and PBS is not considered to be suitable for long-term culture of embryos, especially at early stage of cleavage. In M-16 medium, developing rate of demi-embryos of which pair underwent development to form eublastocysts was 15.8% at 2-cell stage, 16.8% at 4-cell stage, 38% at 8-cell stage, 89.6% at morula stage and 94.4% at blastocyst stage, respectively. The more rapid and efficient production of demi-embryos and higher viability after bisection can be expected by softening zona pellucida with pronase and by selecting morulae or blastocysts rather than embryos at early stage of cleavage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.1
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• pp.62-67
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• 2002

An efficient system of rice microspore culture could contribute to the production of genetically modified rice. The microspores were isolated by mechanical or shed methods. The number of microspores per 100 anthers isolated at uninucleate stage was higher than (or similar to) those at binucleate stage in isolation method with pestle or spatular, but microspore divisions were not easily observed on both stages. On the other hand, pollen division in shed pollen culture was observed more frequently at uninuclear than at binuclear stage. Cold pretreatment at 1$0^{\circ}C$ for 10 days resulted in the best multicellular division to produce microcalli at 12.5% efficiency in shed microspores. Heat shock at 33$^{\circ}C$ for one hour before or after pollen shedding enhanced cell division and callus formation. Out of twelve green regenerants, two were haploids and ten were diploids based on the chromosome analysis of root tips. The size of stoma was 12$^{m}$ m in haploids and 15 ${\mu}{\textrm}{m}$ in diploids determined by scanning electron microscope (SEM).

• Journal of Plant Biology
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• v.36 no.1
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• pp.51-57
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• 1993

The microtuber was efficiently formed on SH medium containing 9% sucrose from the in vitro propagated shoot of potato (Solanum tuberosum cv. Sumi). In order to investigate gene expression depending on the development stage of microtuber, we examined the changes of peroxidase and esterase activities, and their isozyme patterns as well. Peroxidase and esterase activities were the highest at the 7 day-culture of the microtuber and subsequently decreased on the stage of microtuberization, whereas esterase activity increased at the stage of 60 day-culture. However, their activities in the ordinary tuber were higher than those of 60 day-cultured microtuber. In addition, in the peroxidase isozyme pattern two new bands of pI 7.05 and pI 4.65 were appeared at the 15- day and 60 day-cultures, respectively, as shown by isoelectric focusing. Various bands in the sterase isozyme pattern were shown at the 7 day-culture, and the band patterns were a large difference, comparing those of shoot and tuber. New bands in the esterase isozyme pattern also appeared at the 15 day- (pI4.52) and 60 day-cultures (pI 4.48). These results suggest that the changes of peroxidase and esterase activities and isozyme patterns are an important factor in the differentiation and development of potato.

• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.1069-1078
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• 2013

The paper is about teaching culture in a language learning. There are many teachers who are afraid of teaching foreign language with culture. They are delighted to teach politics, economics, history, art and literature as objective culture. But they are hesitant to teach subjective culture which is connected with a communication competency. The paper suggests three stages to instruct culture in a schoolroom. The first stage, it is growing out of the self-centered view. The second step, be developing self-consciousness through comparing mother culture with target culture. The last stage, it has to response to appropriately target culture. The teaching materials for the model suggested are two movies. Because the cultural aspects in the moves are subjective culture, so it has something in common with target cultural situations in a language learning. This method which is teaching culture in a the language learning has the advantage of being easy to teachers and learners. Most students like to watch a movie. The teaching material is The Chronicles of Narnia : The Lion, the Witch and The Wardrobe와 Guess Who?. I hope that this suggestion for cultural teaching is helpful for understanding each other.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.617-621
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• 2002

In order to optimize the carrot hairy root culture for SOD production, a fed-batch culture of hairy roots was performed in a bioreactor. Maximum SOD activity was obtained when the hairy roots were transferred to the MS medium containing 110 g/1 concentration of sucrose. By controlling the sucrose concentration (70 g/1 sucrose for growth and 110 g/1 sucrose far production, respectively) In a two-stage fed-batch culture, 29 g/1 of the hairy roots was obtained based on the final dry mass. The volumetrically determined SOD activity and productivity in the fed-batch culture were about 6 times higher than those from the flask culture containing sucrose at 30 g/1 concentration.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.77-86
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• 1998

The uptake of glucose for metabolism and growth is essential to most animal cells and is mediated by glucose-transporter (GLUT) proteins. The aim of this study was to determine which class of glucose transporter molecules was responsible for uptake of glucose in the mouse early embryo and at which stage the corresponding genes were expressed. In addition, co-culture system with vero cell was used to investigate the effect of the system on GLUT expression. Two-cell stage embryos were collected from the superovulated ICR female and divided into 3 groups. As a control, embryos were cultured in 0.4% BSA-T6 medium which includes glucose. For the experimental groups, embryos were cultured in either co-culture system with vero cells or glucose-free T6 medium supplemented with 0.4% BSA and pyruvate as an energy substrate. 2-cell to blastocyst stage embryos in those groups were respectively collected into microtubes (50 embryos/tube). Total RNA was extracted and RT-PCR was performed. The products were analysed after staining ethidium bromide by 2% agarose gel electrophoresis. Blastocysts were collected from each group at l20hr after hCG injection. They were fixed in 2.5% glutaraldehyde, stained with hoechst, and mounted for observation. In control, GLUT1 was expressed from 4-cell to blastocyst. GLUT2 and GLUT3 were expressed in morula and blastocyst. GLUT4 was expressed in all stages. When embryos were cultured in glucose-free medium, no significant difference was shown in the expression of GLUT1, 2 and 3, compared to control. However GLUT4 was not expressed until morular stage. When embryos were co-cultured with vero cell, there was no significant difference in the expression of GLUT1, 2, 3 and 4 compared to control. To determine cell growth of embryos, the average cell number of blastocyst was counted. The cell number of co-culture ($93.8{\pm}3.1$, n=35) is significantly higher than that of control and glucose-free group ($76.6{\pm}3.8$, n=35 and $68.2{\pm}4.3$, n=30). This study shows that the GLUT genes are expressed differently according to embryo stage. GLUTs were detectable throughout mouse preimplantation development in control and co-culture groups. However, GLUT4 was not detected from 2- to 8-cell stage but detected from morula stage in glucose-free medium, suggested that GLUT genes are expressed autocrinally in the embryo regardless of the presence of glucose as an energy substrate. In addition, co-culture system can increase the cell count of blastocyst but not improve the expression of GLUT. In conclusion, expression of GLUT is dependent on embryo stage in preimplantation embryo development.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.385-391
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• 2022

Quality evaluation of beef carcasses is an important issue in the livestock industry. Recently, through the AI monitor system based on artificial intelligence, the quality manager can receive help in making accurate decisions based on the analysis of beef carcass images or result information. This artificial intelligence dataset is an important factor in judging performance. Existing datasets may have different surface orientation or resolution. In this paper, we proposed a two-stage classification model that can efficiently manage the grades of beef carcass image using deep learning. And to overcome the problem of the various conditions of the image, a new dataset of 1,300 images was constructed. The recognition rate of deep network for 5-grade classification using the new dataset was 72.5%. Two-stage evaluation is a method to increase reliability by taking advantage of the large difference between grades 1++, 1+, and grades 1 and 2 and 3. With two experiments using the proposed two stage model, the recognition rates of 73.7% and 77.2% were obtained. As this, The proposed method will be an efficient method if we have a dataset with 100% recognition rate in the first stage.

• Safety and Health at Work
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• v.12 no.1
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• pp.20-27
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• 2021

Background: Incentive and penalty (I/P) programs are commonly used to increase employees' safety outcomes, but its influence on employees' safety outcomes is under-investigated. Moreover, under developed economies lack safety culture and there is dearth of literature focusing on empirical studies over there [1]. Based on these gaps, this study attempts to see the impact of I/P programs on safety outcomes in a developing country. Methods: The study was carried out in three stages, where Stage I revealed that selected 45 organizations were deficit of safety culture and practices, while only three firms were found good at safety practices. At Stage II, these three firms were divided in two clusters (groups), and were probed further at Stage III. At this stage group, one was manipulated by providing incentives (experimental group) and employees' responses in terms of safety motivation and performance were noticed. Results: It was observed that the experimental group's safety motivation and performance had improved (both for immediate and 1-month later performance). The results were further probed at Phase 3 (after 3 months), where it was found that the benefits of I/P programs were not long lasting and started replenishing. Conclusion: Findings of the study helped researchers conclude that safety incentives have only short-term influence on safety outcomes, while a long-term and permanent solution should be found.