• Restorative Dentistry and Endodontics
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• v.34 no.4
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• pp.356-363
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• 2009

The purpose of this study was to evaluate the viability of periodontal ligament cells in rat teeth using slow cryo-preservation method under pressure by means of MTT assay and WST-1 assay. Eighteen teeth of Sprague-Dawley white female rats of 4 week-old were used for each group. Both sides of the first and second maxillary molars were extracted as atraumatically as possible under Tiletamine anesthesia. The experimental groups were group 1 (Immediate control), group 2 (Cold preservation at $4^{\circ}C$for 1 week), group 3 (Slow freezing), group 4 (Slow freezing under pressure of 3 MPa). F-medium and 10% DMSO were used as preservation medium and cryo-protectant. For cryo-preservation groups, thawing was performed in $37^{\circ}C$water bath, then MTT assay and WST-1 assay were processed. One way ANOVA and Tukey method were performed at the 95% level of confidence. The values of optical density obtained by MTT assay and WST-1 were divided by the values of eosin staining for tissue volume standardization. In both MTT and WST-1 assay, group 4 showed significantly higher viability of periodontal ligament cells than group 2 and 3 (p < 0.05), but showed lower viability than immediate control group. By the results of this study, slow cryo-preservation method under pressure suggests the possibility for long term cryo-preservation of the teeth.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.2
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• pp.127-136
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• 2010

This study is aimed at reviewed and analyzed in order to suggest the improved plans related to natural monuments. The summary of this study is as followings; First, Replacing the current term 'cultural properties', which denotes the meaning of 'goods', we need to devise an new categorization that separates such properties into cultural heritage and natural heritage under the national heritage framework. Second, the designation criteria for natural monuments should be divided into the individual realm for animals and plants respectively, since they are not divided in the current Act. Third, the guidelines for naming of natural monuments should be established with the following new categories in accordance with the clear standards. Fourth, such imbalances require us to give priority to the relatively neglected types and areas. Fifth, as the big and old trees account for more than a half of the designated plants, it is necessary to search out new resources(wet plant communities, seashores, sand dune plant communities, etc.) such as geological resources, mineral springs, hot springs, and fossils that are in danger of completely being exploited and exhausted. While most of the designated animals are protected nationally, the existing designation system is required to protect habitats and breeding places for the systematic and efficient conservation. Sixth, as long as we need to preserve those historical and cultural resources for the future generations from national and global perspectives, we should enhance their values by designating them as natural monuments even though they are protected by other regulations such as the natural environment area. Seventh, as a result of the survey, we found that more budgets and experts in the local governments, more empowered organizations, more active public participation should be provided for the better Natural Monument management in Korea. Eighth, the Lap of Natural Heritage in the National Research Institute of Cultural Heritage needs to be developed to the Natural Heritage Institute to conduct the diverse activities such as researches, restoration, exhibition and education programs in a systematic and efficient way. Ninth and the last, major damages to natural monuments can be generally categorized into the artificial one and natural one, respectively. The artificial damages include toxics, soil covering, excessive humidity, fire, construction and management works, unlawful damages, fishing, oil spillage, etc, and the natural ones include lightning, storms(typhoons), heavy snowfalls, damage by insects and diseases, lack of prey, etc. This study will become meaningful in that it proposes specific measures for the improvement of the institutions, designation, and management of natural monuments on the basis of the comprehensive analysis on natural monuments. We wish to leave the other subjects related with this study to the future researches.

• Journal of Intelligence and Information Systems
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• v.22 no.2
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• pp.81-96
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• 2016

As the internet has become widespread and easy to access everywhere, it is common for people to search information via online search engines such as Google and Naver in everyday life. Recent studies have used online search volume of specific keyword as a measure of the internet users' attention in order to predict disease outbreaks such as flu and cancer, an unemployment rate, and an index of a nation's economic condition, and etc. For stock traders, web search is also one of major information resources to obtain data about individual stock items. Therefore, search volume of a stock item can reflect the amount of investors' attention on it. The investor attention has been regarded as a crucial factor influencing on stock price but it has been measured by indirect proxies such as market capitalization, trading volume, advertising expense, and etc. It has been theoretically and empirically proved that an increase of investors' attention on a stock item brings temporary increase of the stock price and the price recovers in the long run. Recent development of internet environment enables to measure the investor attention directly by the internet search volume of individual stock item, which has been used to show the attention-induced price pressure. Previous studies focus mainly on Dow Jones and NASDAQ market in the United States. In this paper, we investigate the relationship between the individual investors' attention measured by the internet search volumes and stock price changes of individual stock items in the KOSDAQ market in Korea, where the proportion of the trades by individual investors are about 90% of the total. In addition, we examine the difference between industries in the influence of investors' attention on stock return. The internet search volume of stocks were gathered from "Naver Trend" service weekly between January 2007 and June 2015. The regression model with the error term with AR(1) covariance structure is used to analyze the data since the weekly prices in a stock item are systematically correlated. The market capitalization, trading volume, the increment of trading volume, and the month in which each trade occurs are included in the model as control variables. The fitted model shows that an abnormal increase of search volume of a stock item has a positive influence on the stock return and the amount of the influence varies among the industry. The stock items in IT software, construction, and distribution industries have shown to be more influenced by the abnormally large internet search volume than the average across the industries. On the other hand, the stock items in IT hardware, manufacturing, entertainment, finance, and communication industries are less influenced by the abnormal search volume than the average. In order to verify price pressure caused by investors' attention in KOSDAQ, the stock return of the current week is modelled using the abnormal search volume observed one to four weeks ahead. On average, the abnormally large increment of the search volume increased the stock return of the current week and one week later, and it decreased the stock return in two and three weeks later. There is no significant relationship with the stock return after 4 weeks. This relationship differs among the industries. An abnormal search volume brings particularly severe price reversal on the stocks in the IT software industry, which are often to be targets of irrational investments by individual investors. An abnormal search volume caused less severe price reversal on the stocks in the manufacturing and IT hardware industries than on average across the industries. The price reversal was not observed in the communication, finance, entertainment, and transportation industries, which are known to be influenced largely by macro-economic factors such as oil price and currency exchange rate. The result of this study can be utilized to construct an intelligent trading system based on the big data gathered from web search engines, social network services, and internet communities. Particularly, the difference of price reversal effect between industries may provide useful information to make a portfolio and build an investment strategy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.9
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• pp.1140-1147
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• 2007

A recipe for diet kimchi containing 20% of sea tangle to Korean cabbage kimchi (SK) was developed for weight reduction purpose. The fermentation process of SK showed typical Lactobacillus sp. growth pattern like other kimchis. The effects of SK on weight reduction was studied in high fat diet (HFD) fed rats (n=40). Diet groups used for the animal study were HFD, HFD supplemented either with Korean cabbage kimchi used as experimental control (HCK), or with SK (HSK), or with J-kimchi (JK) which was purchased at market (FJK). The effect of kimchi on preventing obesity in rat fed HFD was found to be obvious by means of reducing visceral fat contents and improving serum lipid profiles through enhancing the lipid excretion in the feces (p<0.05). Leptin concentration of rat was significantly decreased by kimchi consumption (p<0.05). This result can be interpreted that adipocytes in these animals were fewer than that of HFD group. The plasma bililubin concentration was lower in kimchi group than HFD, meaning that returning bile from ileum to the liver was reduced. When the observe beneficial effects of kimchi on preventing obesity were compared among kimchi groups, SK only reduced the relative visceral fat contents significantly than other kimchi groups (p<0.05). Besides this, other parameters such as plasma lipid profiles, feces lipids, leptin, and bililubin concentration were not significantly different, even though the most beneficial effect on these parameters was observed from SK. In conclusion, long term consumption of SK seems to have a beneficial effect on the prevention of obesity through enhancing the excretion of lipids in the feces. The dietary fiber content of SK was increased by 7% compared to CK when 20% of sea tangle was added.

• Journal of Yeungnam Medical Science
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• v.12 no.1
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• pp.84-95
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• 1995

A clinical and histopathological study was performed on ninety-four patients with nephrotic syndrome (91 idiopathic and 3 secondary) who were admitted to Department of Internal Medicine, Yeungnam University Hospital during the period of nine years, from January 1985 to May 1994. The results were as following. 1. the ratio of male to female was 1.76:1. In young age group, minimal change was the most predominant type. In old age group, membranous glomerulonephritis and focal glomerulosclerosis were predominant types. 2. The primary nephrotic syndromes were 96.8% and secondary nephrotic syndromes were 3.2%. Histopathologic findings of 94 renal biopsy tissue were classified into minimal change (43.6%), mesangial proliferative glomerulonephritis (29.8%), membranous glomerulonephritis (12.8%), TypeI membranous proliferative glomerulonephritis (4.3%), focal glomerulosclerosis (3.2%) and others (6.4%). 3. The response of eighty-six patients treated with steroid showed complete remission in 51.2%, partial remission in 20.9%, steroid dependent in 2.3%, and no effect in 25.6% of cases respectively. The response to steroid therapy was most effective in the patients with minimal change lesion. 4. In the patient with membranous proliferative glomerulonephlitis, long-term angiotensin converting enzyme inhibitor treatment showed less deterioration of renal function.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1114-1121
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• 2018

Purpose: We report the clinical outcomes of patients undergoing additional widening of the limbal incision to prevent disease recurrence after conjunctivo-limbal autograft combined with pterygial excision. Methods: We retrospectively compared 95 eyes with primary and 12 eyes with recurrent pterygia randomized to treatment via two surgical methods: conjunctivo-limbal autograft alone and combined with widening of the limbal incision to allow for pterygial removal. We widened the limbal incisions by 1 mm on both the superior and inferior limbal margins and removed the pterygia. The outcomes were compared between 39 eyes undergoing conjunctivo-limbal autograft alone and 68 eyes undergoing conjunctivo-limbal autograft with widening of the limbal incision. Results: The mean overall postoperative follow-up period was $29.6{\pm}10.5months$ and conjunctivo-limbal autograft alone group was $27.4{\pm}11.5months$, combined with widening of the limbal incision group was $30.7{\pm}9.7months$. Six pterygia (15.4%; four primary and two recurrent) developed in those undergoing conjunctivo-limbal autograft alone and two (2.9%; one primary and one recurrent) in those undergoing additional widening of the limbal incision; the recurrence rate differed significantly between the two groups (p < 0.05). In the group treated with conjunctivo-limbal autograft alone, the mean time to development of a new primary pterygium was $6.3{\pm}3.4months$ and that to development of a recurrent pterygium $4.3{\pm}2.5months$; the respective values for the group undergoing additional widening of the limbal incision were $12.1{\pm}2.6$ and $8.4{\pm}4.6months$; the recurrence rates differed significantly (p < 0.05). Conclusions: Conjunctivo-limbal autograft with additional widening of the limbal incision used to treat both new primary and recurrent pterygia was more effective in terms of reducing pterygial recurrence than conjunctivo-limbal aAutograft alone.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.125-133
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• 2011

This study was conducted on greenhouses whose side heights had been raised after the columns of 1-2W basic type greenhouses had been cut and welding with the same-sized pipes. When the wind load or snow load affects restructured pipe greenhouse like this, those parts will be structurally unsafe. To examine this, the bending strength of welded columns were measured through four stages and compared with the pipes in their original condition. Results are as follows. In the case of a bending test on welded joints about steel pipes used for greenhouses, satisfactory results couldn't be drawn because sections of both ends and the loading parts couldn't endure loads and sank regardless of loading methods. Partial problems could be solved by inserting inside pipe(steel bar) at the sections and the loading parts, but it was necessary to devise more satisfactory bending test methods. The strength of welded joints wasn't much different compared with original conditions and demonstrated only slight differences according to the sample production conditions. However, significant incompleteness in the welding process was expected to cause a decisive loss in strength. On the assumption that there were no problems in the welding process or with regard to the inclination of sub materials for columns after connection, it was deemed reasonable to assume that the strength of welded pipes was about 84~90% of the strength of the pipes in their original condition. Considering mid- and long-term strength decline following the onset of rust at joints or welding sections, structural changes in the main sub materials that are used for greenhouses at farmhouses have to be avoided to ensure structural safety, unless these changes are inevitable.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.125-157
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• 2018

In the reality that the seriousness and concern about the youth problem is increasing, this study focuses on the vision plan project supporting the NEET youth in the social welfare field. Therefore, this study analyzed how the social workers recognized the NEET problem before participating in the project, what difficulties they experienced in the process of the project, and how they coped with these difficulties. The results of the study are as follows. Social workers were saddened by the seriousness of the youth problem before their participation, but they recognized that there was no way to solve it and many social workers were not fully aware of the youth or NEET issues. In this context, in the course of running a project with NEET youth, social workers experienced difficulties due to the nature of the NEET youth, difficulty in forming a relationship with NEET youth, and difficulties for young people not to spend time in the program. And social workers also faced difficulties due to the lack of know-how in the project, difficulties in operating the center alone, and difficulty in achieving employment goals. In the process of coping with these difficulties, social workers have actively sought, persuaded and supported the NEET youths to participate in the project, adapted the time, place and method to the youth, and removed the stigmatization element in the project. They also worked closely with local residents, local institutions and municipalities, formed networks, and changed the viewpoint of providing work experience rather than getting young people, but seeing long-term outcome. As a result, social workers have experienced not only individual change but also social welfare organization, field, community and local institutional change. Based on these results, this study suggested that the social welfare practice field should provide various activities in the process of supporting the youth gap year policy. In addition, this study suggests that the social workers play a role in connecting various actors rather than suppliers when working with young people, and that the social welfare field should expand the scope of project to include youth.

• Journal of Legislation Research
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• no.53
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• pp.61-107
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• 2017

It has been seventy-two years since the Korean Peninsular was divided into South and North Korea. When Korea was liberated from Japanese colonial rule in August 1945, the South and North established a capitalist system and a socialist system (communism) respectively, intensifying the ideological conflict and confrontation. The division of Korea was not confined to political and economical aspects, but extended to legal system, making it difficult to find legislative homogeneity in the two. The long-term situation of the divided nation results in a social phenomenon accompanied by legal division. For instance, shortly after its liberation from Japan's colonial rule, North Korea responded quickly to secure legal stability to govern the northern part while the Soviet army troops were stationed in it. Based on Marx and Engels' historical materialism, the North drove a change in its ideological superstructure by repealing the privatization of land property which was the means of production and finally enforced land nationalization, in common with other socialist states including the former Soviet Union. The North's land reform made under the guise of fulfilling national independence and doing away with anti-seigneurial and anti-feudalistic relations, has led to a wide difference in the systems between the South and Korea. This paper focuses on the legal systems of South and North Korea and is aimed at exploring the legal characteristics and environment of the North which became secluded from the world while engaging in socialist experiments for the past seventy two years against capitalism. Ongoing studies of legal system integration will be briefly discussed. The legal status of South and North Korea as a political entity will be investigated to overcome legal system division; and the characteristics of South-North relationship in legal terms and the limitations of the North's legal system will be also examined. Moreover, the directions for integrating legal systems and the plan for resolving legal system division will be suggested.

• Korean Journal of Remote Sensing
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• v.35 no.5_1
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• pp.665-679
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• 2019

Mesoscale soil moisture measurement from the promising Cosmic-Ray Neutron Probe (CRNP) is expected to bridge the gap between large scale microwave remote sensing and point-based in-situ soil moisture observations. Traditional calibration based on $N_0$ method is used to convert neutron intensity measured at the CRNP to field scale soil moisture. However, the static calibration parameter $N_0$ used in traditional technique is insufficient to quantify long term soil moisture variation and easily influenced by different time-variant factors, contributing to the high uncertainties in CRNP soil moisture product. Consequently, in this study, we proposed a modified traditional calibration method, so-called Dynamic-$N_0$ method, which take into account the temporal variation of $N_0$ to improve the CRNP based soil moisture estimation. In particular, a nonlinear regression method has been developed to directly estimate the time series of $N_0$ data from the corrected neutron intensity. The $N_0$ time series were then reapplied to generate the soil moisture. We evaluated the performance of Dynamic-$N_0$ method for soil moisture estimation compared with the traditional one by using a weighted in-situ soil moisture product. The results indicated that Dynamic-$N_0$ method outperformed the traditional calibration technique, where correlation coefficient increased from 0.70 to 0.72 and RMSE and bias reduced from 0.036 to 0.026 and -0.006 to $-0.001m^3m^{-3}$. Superior performance of the Dynamic-$N_0$ calibration method revealed that the temporal variability of $N_0$ was caused by hydrogen pools surrounding the CRNP. Although several uncertainty sources contributed to the variation of $N_0$ were not fully identified, this proposed calibration method gave a new insight to improve field scale soil moisture estimation from the CRNP.