• Korean Journal of Animal Reproduction
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• v.20 no.4
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• pp.379-384
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• 1997

Superovulation with exogenous gonadotropins creates a spectrum of pre or periovulatory hormonal changes with subsequent detrimental effects on oocyte quality, fertilization, embryo development, implantation and maintenance of pregnancy. Our recent study determined potential roles for insulin-like growth factor-1 (IGF-1) in uterine environment regulation and preimplant tation in the rat. The evidence indicates that IGF-l may play an important role in the main tenance of a receptive uterine environment for embryonic development and the regulation of decidualization. Embryonic loss and failure of implantations following superovulation may be partially attributed to disturbances in uterine IGF-l action as observed in this study. We investigated the effects of superovulatory doses of gonadotropins on frequency of chromosomal a abnormalities of mouse embryos. Chromosome a analysis of mouse zygotes and 8- to 16-cell stage embryos from spontaneously ovulated, 5, 10, and l 15 lU pregnant mare serum gonadotropin (PMSG) superovulated mice was carried out. Aneuploidy, polyploidy and structural chrom- osomal abnormalities were detected among the four groups. However, only polyploidy was correlated with superovulation. In 10 and 15 IV PMSG treated groups, the rate of polypoidy was 2.9% and 10.5%, respectively. Furthermore, there was a dose reponse relationship between the PMSG dose and the incidence of embryonic p polyploidy (P

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.35-35
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• 2005

Recombinant human $interferon-{\beta}-1a(rIFN-{\beta})$ is a single glycosylated protein (at N80, 1N) with anti-viral activity. However, present drugs have a relatively short serum half-life of $rIFN-{\beta}$, thus patients suffer from frequent $infections.^{1)}$ To improve its half-life, eight glycosylation analogs were prepared, which have additional N-linked glycosylation consensus sequences (N-X-T/S) within the $IFN-{\beta}$ molecule and/or at C-terminal. Each $rIFN-{\beta}$ analog was examined for the presence of additional N-linked glycosylation and the maintenance of anti-viral activity in CHO cells. The molecular weights of five analogs were not changed. However, two analogs, R27T within $rIFN-{\beta}$ (27 kDa, 2N) and GNITVNITV at C-terminal (29kDa, 2N), showed a clear increase in molecular weights, compared to native $rIFN-{\beta}$ (23 kDa, 1N). And another combined analog of R27T+GNITVNITV showed increased molecular weight (33 kDa, 3N). It was confimed that the molecular weight increment of analogs was caued by the N-linked glycosylation with the treatment of N-glycansae. In the case of anti-viral activity, the analog GNITVNITV showed a reduction in activity compared to native $IFN-{\beta}$, whereas the analogs R27T and R27T+GNITVNITV were found to have distinctly increased activities. Pharmacokinetic study in rats also disclosed that the analogs R27T and R27T+GNITVNITV had 2 3 fold increased serum half-life, respectively. In conclusion, the addition of N-linked glycosylation in $rIFN-{\beta}$ increased serum half-life, thereby its less frequent administration will be expected.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.495-501
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• 2003

Impaction is defined as the cessation of the eruption of the tooth caused by a clinically or radiographically detectable physical barrier in the eruption path or by the ectopic position of tooth germ. Besides the third molars and the maxillary canines, the most common impacted tooth is the second premolar. The overall frequency of premolar impaction has been reported to be 0.5%. In some cases, orthodontic traction and surgical repositioning may be indicated. When impacted second premolar is involved with prolonged retained second primary molar, extraction of primary molar and space maintenance lead to eruption of second premolar. In these cases, all patients visited to department of pediatric dentistry of Kyungpook National University Hospital for the chief complaint of unerupted second premolar. Extraction of prolonged retained second primary molar and space management are tried for spontaneous eruption of impacted second premolar tooth. The results were as follows: 1. When impacted second premolar is involved with prolonged retained second primary molar, minimal treatment via elimination of primary molar leads to successful results. 2. Proper space management and periodic radiographic examination are required before eruption of second premolar. 3. Sufficient time must be allowed for confirm of tooth movement before orthodontic traction or surgical repositioning. 4. The result is more successful in incomplete root development.

• Korean journal of communication and information
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• v.67
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• pp.209-240
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• 2014

This study observes reporters' awareness on the use of social media and their Core Values by using the Theory of Means-End Chain and drawing conclusions from a Hierarchical Value Map (HVM). In order to analyze reporters' knowledge and awareness on the use of social media via the laddering method, in-depth interviews of 46 reporters were conducted. The study showed that reporters consider sense of kinship, well-balanced understanding, and the desire for knowledge to be important Core Values. The results revealed that the convenience in interpersonal communication, development of intimacy in relationships, entertainment and affection, curiosity, the reduction in the cost of the acquisition of information, understanding of trends in issues, a peek into new information and the maintenance of interests, psychological dependability, and quick updates on information items are considered important Consequences of social media. In the Attributes level, the ability to write postings and links on Facebook and readability and 'follow' and 'mention' features on Twitter were confirmed to be important items in social media. The findings infer that reporters that make use of social media use Twitter and Facebook to build a sense of kinship with other users and gain well-balanced understanding by accessing a lot of information through social media. While this study examined the level of reporters' familiarity with the use of social media via the laddering method, the results cannot be seen as a generalization, as the interviewees were reporters from only the major news organizations.

• Journal of the Korean GEO-environmental Society
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• v.10 no.4
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• pp.15-24
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• 2009

Korea is known to have seasonal frost during winter and the effect of low temperatures and water may cause a weakening of pavements. For that reason, frost protection layers have been constructed in pavements to avoid damage caused by frost action. The practies established in USA and Japan have been adopted as anti-frost design methods in Korea. However, the characteristics of Korean soils are different. Additionally, there is no formulation of a reasonable equation for frost penetration depth and the criterion to identify potentially frost-susceptible soils in present pavement design manuals in Korea. Therefore, adequate pavement design procedures in seasonal frost areas, as well as construction and maintenance practices are required. In this paper, frost penetration depths along national roads in Korea were measured and analyzed over several years. The frost penetration depth was analyzed with respect to the provinces of Korea and sunny/ shaded areas. Additionally, measurement results were compared to the formula of the US Army Corps of Engineers and Ifukube in Japan.

• Journal of the Korean GEO-environmental Society
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• v.18 no.3
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• pp.31-38
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• 2017

The purpose of this study is to propose a chart that can easily estimate the seismic failure probability of small and medium sized earthfill dams with little geotechnical information. By considering the existing method and procedure for estimating the seismic failure probability of a dam, the zero seismic failure probability curve, on which the seismic probability is zero regardless of the geotechnical properties of the dam, was determined in the form of hyperbola in the dam height and freeboard ratio plane. It was confirmed that the dam height-freeboard ratio distribution pattern of the Korean small and medium sized dams was shaped like a hyperbola like the zero seismic failure probability curve. Therefore, a estimation chart was constructed in which a number of seismic failure probability contours are represented by a number of hyperbolas at regular intervals in the dam height-freeboard ratio plane. The proposed chart was applied to the calculation of the seismic failure probability of two small and midium sized dams with relatively well-managed geotechnical properties and the validity of the chart was confirmed by comparison with the results obtained by the existing procedures and methods. In the future, the proposed chart is expected to be useful in considering investment priorities for maintenance and reinforcement of small and medium sized dams in preparation for earthquakes.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.71-79
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• 2015

This paper describes vegetation based soil-media hydroseeding measures that have been previously applied as slope revegetation methods show problems such as insufficient binding force, drying, and insufficient organic matter. In particular, in the case of slope faces in regions where scattering is severe, a vicious circle exists in which remarkably low vegetation cover rates and increases in withering rates over time lead to further decreases in vegetation cover rates, which lead to further increases in erosion and scattering. Therefore, in the present study, environment friendly soil stabilizers were applied for resistance against erosion or scattering and engineering evaluations such as long-term immersion tests and flow resistance tests were conducted to determine appropriate mixing ratios. According to the results of long-term immersion tests utilizing environment friendly soil stabilizers and existing greening soil based materials, 100% collapse occurred at 30 hours and 40 days in the case of soil stabilizer mixing ratios of 0% and 2%, respectively. While the original form of the samples remained intact until the experiment was completed in the case of mixing ratios exceeding 4% indicating that 2% or higher soil stabilizer mixing ratios could affect the maintenance of forms even under extreme conditions. In addition, artificial rainfall tests were conducted on 40, 45, and 55 degree slope faces to evaluate the structural stability of vegetation based materials. Flow resistance tests were conducted on soil stabilizer mixing ratios of 0, 4, 8% to evaluate erosion resistance capability. Based on the results of the tests, environment friendly soil stabilizers applied for prevention of scattering or resistance against erosion by rainwater are considered to provide large effects to reduce losses and loss rates showed a tendency of decreasing rapidly when soil stabilizers were mixed.

• Journal of the Korean Geosynthetics Society
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• v.13 no.1
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• pp.1-9
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• 2014

Expansion of a roadway on a soft ground can cause settlement of the existing road during embankment construction due to the consolidation characteristics of the soft soil. Many problems related to construction and maintenance, such as deterioration of the surface, decreased safety, and decreased structural stability, could affect the existing road. This scenario is especially true if the roadway foundation is a deep thick soft ground. Therefore, engineers should carefully select a proper design based on the characteristics of the soil layer. In this study, the expansion of the second branch of the Namhae Expressway was selected as the target site because this expressway has been constructing on a soft soil layer approximately 50 m thick. The original design was reviewed, problems were discussed and alternative was proposed through value engineering job plan phases: investigation, speculation, evaluation, development and presentation. In addition, the proposed alternative was evaluated on cost, function and value improvement. Compared to the original design, the proposed alternative saved cost and improved the function and overall value.

• Journal of the Korean Geosynthetics Society
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• v.17 no.1
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• pp.65-74
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• 2018

The degree of compaction of embankments is generally measured using the sand replacement method or a soil density gauge. However, these methods include coarse particles, which are relatively large. The degree of compaction is overestimated if the in-situ soil density is simply compared with the density obtained from a Proctor compaction test (KS F 2312, 2001), because the density of coarse particles is higher than that of soil. However, there is no recommended correction for the coarse particle ratio in Korea, thus intentionally increasing the degree of compaction for structures to which large loads are applied or for which compaction is critical. Here, a correction considering the Korean Proctor compaction test and the difference between the maximum allowable particle sizes was recommended after corrections for coarse particle ratios in other countries were collected and analyzed. The degree of compaction was re-estimated by applying the recommended correction to the results of both Proctor compaction and sand replacement tests. The degree of compaction without the correction of coarse particle ratio was overestimated, because the re-estimated degree of compaction decreased as the coarse particle ratio increased. The relatively accurate results obtained from the field application of the correction will offer long-term cost savings due to reduced maintenance fees during operation.

• Journal of Environmental Science International
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• v.17 no.4
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• pp.423-437
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• 2008

Until comparatively lately, the annual time series of the $SO_2$ concentration had been shown in a decreasing trend in Ulsan as well as other Korean cities. However, the high concentration of $SO_2$ was frequently found in the specific countermeasure region including the national industrial complex such as Mipo and Onsan in the Ulsan city for the period of $2001{\sim}2004$. There are many conditions that can influence the high concentration of $SO_2$ at monitoring sites in Ulsan, such as: First, annual usage of the fuel including sulfur increased in comparison with the year before in spite of the fuel conversion policy which wants to use low sulfur oil less than 3% and LNG. Second, point source, such as the power plants and the petroleum and chemistry stacks, was the biggest contributor in $SO_2$ emission, as a analyzed result of both the air quality modeling and the stack tole-monitoring system (TMS) data. And third, the air pollutants that occurred in processes of homing and manufacturing of the fuel including sulfur were transported slow into a special monitoring site by accumulating along the frontal area of see-breeze. It was concluded that Ulsan's current environmental policy together with control methods should be changed into the regulation on total amount of emission, including a market-based emission trading with calculating of atmospheric environmental critical loads, for the $SO_2$ reduction like the specific countermeasure for the $O_3$ and PM10 reduction in the Seoul metropolitan area. And this change should be started in the big point sources of $1{\sim}3$ species because they are big contributors of Ulsan's $SO_2$ pollution. Especially it is necessary to revitalize of the self-regulation environmental management. Other control methods for sustaining the $SO_2$ reduction are as follows: maintenance of the fuel conversion policy, reinforcement of the regional stationary source emission standard, and enlargement of the stack TMS.