• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.141-148
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• 1999

This study was to test whether the viability of bovine hatched blastocysts (HBs) can be maintained after vitrification and thawing. The HBs were produced in vitro at Day 9 and Day 10 after IVF, and they were classified to small (S-HBs; ø$\leq$300 ${\mu}{\textrm}{m}$) and large(L-HBs; ø＞300 ${\mu}{\textrm}{m}$) on the basis of embryo diameter using eyepiece micrometer. As freezing solution, we used EFS35 which consisted of 35% ethylene glycol (EG), 18% ficoll, 0.3 M sucrose and 10% FBS added in mDPBS. Vitrification was taken by two-step method, the HBs were equilibrated in 10% EG for 5 minutes and then shortly exposed in EFS35 and plunged into L$N_2$for 30~45 sec. After thawing, the survival rates were assessed by the re-expansion of the blastocoel during 2 h and 16 h of culture. The results obtained in these experiments were summarized as follows; 1) When the blastocysts(40.8%) recovered at Day 8 after IVF were further cultured for 24 h(Day 9 after IVF) and 48 h(Day 10 after IVF), the rates of HBs were 20.5% and 6.7%, respectively. Also, the total cell number of HBs on Day 9 was significantly higher than that of HBs on Day 10 (p＜0.01). 2) When the effects of freezing solution to the survival of Day 9 L-HBs were examined, the rate of vitrified group (75.7%) was significantly lower than 100% of control and exposed group(p＜0.05). 3) When the survival rates of vitrified HBs according to size and developmental age were examined, the data of L-HBs (75.5%) and S-HBs(63.6%) on Day 9 were slightly higher than those of L-HBs(64.3%) and S-HBs(60.7%) on Day 10. 4) Also, when the in vitro survival of Day 9 HBs was evaluated under different culture condition after thawing, the result in culture medium only (79.3%) was significantly higher than 43.2% in co-culture group (p＜0.05). These results demonstrated that bovine HBs can be successfully cryopreserved by two-step vitrification method using EFS35.

• Geophysics and Geophysical Exploration
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• v.26 no.2
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• pp.52-61
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• 2023

The use of ultra-high-resolution (UHR) seismic surveys to preceisly characterize coastal and shallow structures have increased recently. UHR surveys derive a spatial resolution of 3.125 m using a high-frequency source (80 Hz to 1 kHz). A digital streamer system is an essential module for acquiring high-quality UHR seismic data. Localization studies have focused on reducing purchase costs and decreasing maintenance periods. Basic performance verification and application tests of the developed streamer have been successfully carried out; however, a comparative analysis with the existing benchmark model was not conducted. In this study, we characterized data obtained by using a developed streamer and a benchmark model simultaneously. Tamhae 2 and auxiliary equipment of the Korea Institute of Geoscience and Mineral Resources were used to acquire 2D seismic data, which were analyzed from different perspectives. The data obtained using the developed streamer differed in sensitivity from that obtained using benchmark model by frequency band.However, both type of data had a very high level of similarity in the range corresponding to the central frequency band of the seismic source. However, in the low frequency band below 60 Hz, data obtained using the developed streamer showed a lower signal-to-noise ratio than that obtained using the benchmark model.This lower ratio can hinder the quality in data acquisition using low-frequency sound sources such as cluster air guns. Three causes for this difference were, and streamers developed in future will attempt to reflect on these improvements.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.464-476
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• 2022

In recent years, macroalgal bloom occurs frequently in coastal oceans worldwide. It might be attributed to accelerating climate change. "Green tide" events caused by proliferation of green macroalgae (Ulva spp.) not only damage the local economy, but also harm coastal environments. These nuisance events have become common across several coastal regions of continents. In Korea, green tide incidences are readily seen throughout the year along the coastlines of Jeju Island, particularly the northeastern coast, since the 2000s. Ulva species are notorious to be difficult for morphology-based species identification due to their high degrees of phenotypic plasticity. In this study, to investigate temporal variation in Ulva community structure on Jeju Island between 2015 and 2020, chloroplast barcode tufA gene was sequenced and phylogenetically analyzed for 152 specimens from 24 sites. We found that Ulva ohnoi and Ulva pertusa known to be originated from subtropical regions were the most predominant all year round, suggesting that these two species contributed the most to local green tides in this region. While U. pertusa was relatively stable in frequency during 2015 to 2020, U. ohnoi increased 16% in frequency in 2020 (36.84%), which might be associated with rising sea surface temperature from which U. ohnoi could benefit. Two species (Ulva flexuosa, Ulva procera) of origins of Europe should be continuously monitored. The findings of this study provide valuable information and molecular genetic data of genus Ulva occurring in southern coasts of Korea, which will help mitigate negative influences of green tide events on Korea coast.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.363-373
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• 2022

On April 29, 2021 (1st), June 2 (2nd), and August 17 (3rd), we surveyed benthic macroinvertebrates fauna at Muljangori-oreum wetland in Bonggae-dong, Jeju Island, Korea. Muljangori-oreum wetland was divided into four areas. The survey was conducted in three accessible areas (areas 1-3). As a result of habitat environment analysis, the average monthly temperature from 2017 to 2021 was the highest in July and August and the lowest in December and February. This pattern was repeated. As a result of analyzing changes in vegetation and water surface area through satellite images, normalized difference vegetation index (NDVI) increased from February to July and decreased after July. Normalized difference water index (NDWI) was analyzed to show an inverse relationship. A total of 21 species from 13 families were identified in the qualitative survey and a total of 412 individuals of 24 species from 15 families were identified in the quantitative survey. A total of 26 species from 17 families, 8 orders, 3 classes, and 2 phyla of benthic macroinvertebrates were identified. The dominant species was Chronomidae spp. with 132 individuals (32.04%). Noterus japonicus was a subdominant species with 71 individuals (17.23%). As a result of comparative analysis of species identified in this study and the literature, it was confirmed that species diversity was high for Coleoptera and Odonata. Main functional feeding groups (FFGs) were found to be predators. Habitat orientation groups (HOGs) were found to be swimmers. In OHC (Odonata, Hemiptera, and Coleoptera) group, 17 species (73.91%) in 2021, 23 species (79.31%) in 2016, 26 species (86.67%) in 2018, and 19 species (79.17%) in 2019 were identified. Cybister japonicus, an endangered species II, was confirmed to inhabit Muljangori-oreum wetland in the literature. Ten individuals (2.43%) were also confirmed to inhabit Muljangori-oreum wetland in 2021. Therefore, continuous management and habitat protection are required to maintain the habitat environment of C. japonicus in Muljangori-oreum wetland.

• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.255-262
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• 2000

The aim of this work was to study the effects of ascorbic acid (Asc) and/or ferrous sulfate (Fe$^{2+}$) and spernatozoa preincubation on the in vitro fertilization in porcine. Porcine follicular oocytes matured in culture were inseminated with frozen-thawed boar spermatozoa preincubated for 0, 1, 2, 3, 4 and 5h. The penetration rates (37~51%) were not significantly different between durations of spermatozoa preincubation in medium with 0.1 mM Asc. The addition of 1.0 mM Fe$^{2+}$ during spermatozoa preincubation were not significantly affecting the penetration rates (41~56%). When spermatozoa were preincubated with Asc and Fe$^{2+}$, the penetration rates had a tendency to increase with time of spermatozoa preincubation, and were significantly (P<0.05) higher in spermatozoa preincubated with that than without Asc and Fe$^{2+}$ for 5 h. On the other hand, when spermatozoa were preincubated in fertilization medium without Asc and/or Fe$^{2+}$, the penetration rates were significantly (P<0.05) higher in medium with Fe$^{2+}$ than with Asc or Asc and Fe$^{2+}$ for in vitro fertilization. The rate of polyspermy in penetrated oocytes in medium with Asc and Fe$^{2+}$ decreased with the period of spermatozoa preincubation. Despite different culture conditions for spermatozoa preincubation, no differences were observed in polyspermy rates in the presence of Asc and/or Fe$^{2+}$ These results indicate the advantage of preincubating spermatozoa with Asc and Fe$^{2+}$ and an addition of Fe$^{2+}$ during in vitro fertilization with spermatozoa preincubated maintain penetration potential without increased polyspermy rates on in vitro fertilization in porcine oocytes.on in porcine oocytes.

• Korean Journal of Animal Reproduction
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• v.25 no.1
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• pp.71-77
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• 2001

This experiment was designed to improve the production efficiency of germ-line chimeric mice from phospholipase C (PLC)-$\beta$3 or peroxiredoxin (Prx) E -targeted ($\Delta$) ES cells by the investigating the manipulation conditions and characteristics of Jl ES cells. Four targeting clones were isolated to investigate the karyotypical and morphological stability prior to injection. All clones ($\Delta$PLC$\beta$-3 C3, $\Delta$Prx II C3, C10 and I5) showed more than 80% euploidism, however, most of $\Delta$PLC$\beta$-3 C3 clones were extensively differentiated compared to the other clones. Nine of 13 $\Delta$Prx II chimeras appeared to have at least 80% chimerism, whereas $\Delta$PLC$\beta$-3 C3 chimeras had 20% chimerism at most. Therefore, the morphological stability of ES cells under stable euploidism might mainly affect the production rate of high-coat chimeric mice. To increase the collection rate of injectable blastocysts (IBs), 5 to 10 week -aged C57BL/6J female mice were sacrificed at 3.5 days post-coitum. Ten week-aged mice were the most optimal IB donors by showing the highest collection rate (2.94/mouse) of injectable blastocysts without increase of non-injectable embryos (0.29/mouse). Foster mothers might be another factor because ICR x C57BL/6J F1 foster mother showed more increased productivity in litter size (2.8 vs. 5.6) and chimera (0 vs. 35.3%) than those of ICR foster mothers. In conclusion, the efficient production of germ-line chimeras mainly depends on the maintenance of ES cell morphology during targeting procedure, and the establishment of manipulation conditions might be a key point to maximize it.

• Journal of Popular Narrative
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• v.25 no.3
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• pp.9-40
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• 2019

This study presents an investigation into South Korean films in the 1990s in the aspects of genre change and emotional reorganization. The 1990s witnessed a change of genres and a paradigm shift in the history of Korean films according to the revolutionary changes of the film industry structure and media environment. Believing that these changes had something to do with emotional changes driven by global capitalization symbolized by democratization in 1987 and the foreign currency crisis in 1998, the investigator analyzed the phenomena in film texts and examined the opportunities and context behind them. Unlike previous researches, this study made an approach to the history of Korean films in the 1990s with three points: first, this study focused on why the romantic comedy genre emerged in the 1990s and what stages its formation underwent since there had been no profound discussions about them; secondly, this study analyzed the biggest hits during the transitional period from 1987~1999 to figure out the mainstream genres and emotions during that period since these hits would provide texts to show the genre domain and public taste in a symbolic way; and finally, this study grew out of the separate investigation approach between melodramas and romantic comedies and looked into an emotional structure to encompass both genres to make a more broad and dynamic approach to South Korean films in the 1990s. History flows continuously without severance from previous times. When there is attention paid to inflection points and opportunities in the continuum, it can show the dynamics and structures of changes. This research led to the following conclusions: the mainstream genre of South Korean films had been melodramas until the 1980s. The old convention had been kept to offset or suture contradictions and excessive elements deviant from the structural consistency. Here, the structural consistency refers to no compliance to rational regulations or trade. The process of genre reorganization in the 1990s happened while securing some distance from the convention of making the structural consistency a sacrifice. The direction was to reinforce control through reasonable rationalism and logic of capital. It developed into romance, which would start with comedy to keep distance from the objects through laughter, heighten the level of remarks, and expand criticality, symbolize emotions with taste items, and build through the logic of mutual consensus and practical trade. In the 1990s, the South Korean films thus developed in a direction of moving away from the narrative of urgent pathos based on unconditional familism. It was on the same track as the entry of the South Korean society into the upgraded orbits of democracy and capitalism as the twins of modern rationalism since the latter part of the 1980s.

• Journal of Popular Narrative
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• v.25 no.1
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• pp.165-191
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• 2019

The purpose of this article is to elucidate why the motif of time travel is repeated in the science fiction narrative by examining the functions of this motif in the SF movie series of Star Trek in its narrative and non-narrative aspects. Star Trek IV: The Voyage Home (1986) aims to attract the audience's interest in the story through the use of plausible time travel in the form of the slingshot effect which causes the spacecraft to fly at very fast speeds around an astronomical object. The movie also touches upon the predestination paradox that arises from a change of history in which it describes a formula of transparent aluminum that did not exist at the time. The film also serves as an evocation of the ideology of ecology by including humpback whales in the central narrative and responding to the real issue of the whale protection movement of the times. Star Track VIII: First Contact (1996) intends to interest the audience in the narrative with the warp drive, a virtual device that enables travel at speeds faster than that of light and a signature visual of Star Trek, at the time of its birth through time travel. The film emphasizes the continuation of peaceful efforts by warning the destruction of humanity that nuclear war can bring. It tackles with the view of pacifism and idealism by stressing the importance of cooperation between countries in the real world by making the audience anticipate the creation of the United Federation of Planets through encounters with the extraterrestrial. Star Trek: The Beginning (2009) improves interest through the idea of time travel to the past, this time using a black hole and the parallel universe created thereby. The parallel universe functions as a reboot, allowing a new story to be created on an alternate timeline while maintaining the original storyline. In addition, this film repeats the themes pacifism and idealism shown in the 1996 film through the confrontation between Spock (and the Starfleet) and Nero, the destruction of the Vulcan and the Romulus, and the cooperation of humans and Vulcans. Eventually, time travel in three Star Trek films has the function of maximizing the audience's interest in the story and allowing it to develop freely as a narrative tool. It also functions as an ideal solution for commenting on current problems in the non-narrative aspect. The significance of this paper is to stress the possibility that the motif of time travel in SF narrative will evolve as it continues to repeat in different forms as mentioned above.

• Journal of Popular Narrative
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• v.25 no.3
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• pp.211-266
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• 2019

Films of the 1960s in both Korea and Egypt share many common characteristics. These include the main trend of such films' in addition to some of the political situations. This trend mainly relates to the adaptation of novels into films. In the late 1940s, Andre Bazin wrote his ideas about a similar phenomenon in Europe and the United States. Based on Bazin's thoughts and other examples for films adapted from novels in the 1940-60s, I found that the trend in both Korea and Egypt can be explained as an international phenomenon, in which film developed to a further stage due to a dialectic between content and form after the increase in the development of film techniques. The trend in Korea is believed to have led to the so-called golden era of Korean movies, while in Egypt films adapted from literature were not able to earn high profits, even though in a 1996 list of the best 100 Egyptian films, 23 had been adapted from novels. To explain the reasons behind this phenomenon, I looked into the internal demand from filmmakers themselves to further develop the industry through the articles written at that time. In addition, I explored the different situations and policies that influenced film production in both countries in the 1960s. I found that political situations and policies could have helped in the continuity of such trend, but it is difficult to consider these as the main reason for its creation, in contrast to the internal demand, which I believe is the main reason for the creation of such direction.

• Journal of Popular Narrative
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• v.25 no.3
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• pp.349-383
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• 2019

This paper examined the meaning and task of romance research with a focus on Reading the Romance(1984) by Janice A. Radway. This book, which analyzes romance texts by examining the situation and meaning of reading romance by women readers integrating between cultural studies and literary studies, is one of the most popular studies on the romance genre. Radway scrutinized the practical significance of reading romance in a community of women readers. Through a study involving questionnaires and in-depth interviews, she found that for women, romance reading is a 'compensatory fiction' that brings happiness and emotional redemption through a sense of liberation achieved by escaping from patriarchal daily life. The romance that women prefer is composed of 4 stages and 13 divisions: 'Encounter → Attest → Recovery → Happy End'. It also maintains a formula that begins with an immature female character's identity crisis and ends with a blissful union that recognizes the intrinsic value of the main character, who has turned into a man who is considerate of the women. Therefore, romance plays the role of pursuit of the 'female utopian fantasy' and at the same time a reconciliation of women to patriarchy. Feminist critics of the day criticized this argument. However, reading romance is a 'feminine reading', and romance is literature about the functional relationship between women's lives and patriarchy. Yet the interpretation could differ depending on the different viewpoints and definitions of the women's utopian fantasy. In recent years, the conditions of female reader's lives, awareness and imagination have been changing rapidly. As a result, the female utopian fantasy has also changed significantly. Nevertheless, women's lives in the real patriarchal system are still contradictory, and their adventurous imagination is spreading in alternative spaces such as the subculture. In this regard, the question is about the definition of romance and the meanings of romance research are still important task.