• Korean Journal of Environment and Ecology
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• v.31 no.4
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• pp.349-364
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• 2017

Duckweed family (Lemnaceae Martinov), including the genus Lemna L., is a typical floating aquatic perennial plant, and about five genera and 40 species in the family are in wide distribution around the world except the polar regions. The genus Lemna is the smallest and the simplest plant among the angiosperms. It has a characteristic of doubling every three days with fast vegetative propagation, which helps the organisms to increase in rapid growth. As such, the plant is ideal for environmental pollution assessment and toxicity test. Although taxonomists and scholars have used different scientific names for the species, many of them have agreed that there is only one member of species of the genus Lemna in Korea. Paying attention to the external morphological variation observed in the Korean genus Lemna, we conducted a molecular phylogenetic analysis to identify the entity of the Korean Lemna species and to investigate the possibility of two or more members of the species existing in Korea. We determined and aligned the DNA sequences of the atpF-H region of the chloroplast DNA in 37 populations of the nationally distributed Lemna species. The results showed that the sequence length of the cp DNA atpF-H region was 463-483 bp, the length of the aligned sequences was 488 bp, and the number of variation site in nucleotide sequences was 47. There were two types of aligned sequences of the cp DNA atpF-H region from 37 populations of Lemna species in Korea. The maximum parsimony analysis revealed that the Korean Lemna consists of two clades, and one of them had two subclades. The results suggest that, contrary to the general understanding, at least two taxa (L.aequinoctialis, L.minor) exist in Korea.

• Journal of radiological science and technology
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• v.34 no.3
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• pp.239-244
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• 2011

In this study, we evaluated diffusion weighted imaging (DWI) to investigate whether the DWI parameters can predict characteristic parameters on pathologic specimens of tumor or not. CFPAC-1 was injected subcutaneously on the back flank of athymic nude mice (n=13) then two tumors were initiated on each mouse (2${\times}$13=26 tumors). The mice were sacrificed to make specimen immediately after initial MR imaging then were compared with the MR image. A dedicated high-field (7T) small-animal MR scanner was used for image acquisitions. A T1 and T2 weighted axial image using RARE technique was acquired to measure the T2 values and tumor size. DWI MR was performed for calculating ADC values. To evaluate tumor cellularity and determine the levels of MVD, tumor cells were excised and processed for H-E staining and immunostaining using CD31. T2 values and ADC values were computed and analyzed for each half of the tumors and compared to the correlated specimens slide. Median ADC within each half of mass was compared to the cellularity and MVD in the correlated area of pathologic slide. The mean of ADC value is $0.7327{\times}10^{-3}$ $mm^2/s$ and standard deviation is $0.1075{\times}10^{-3}$ $mm^2/s$. There is a linear relationship between ADC value and tumor necrosis (R2=0.697, p< 0.001). DW image parameters including the ADC values can be utilized as surrogate markers to assess intratumoral neoangiogenesis and change of the internal structure of tumor cells.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.217-223
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• 2013

Background: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and the outcomes for patients are still poor. It is important to determine the original type of synchronous multinodular HCC for preoperative assessment and the choice of treatment therapy as well as for the prediction of prognosis after treatment. Aims: To analyze clinicopathologic characteristics and prognoses in patients with multicentric occurrence (MO) and intrahepatic metastasis (IM) of synchronous multinodular hepatocellular carcinoma (HCC). Methods: The study group comprised 42 multinodular HCC patients with a total of 112 nodules. The control group comprised 20 HCC patients with 16 single nodular HCC cases and 4 HCC cases with a portal vein tumor emboli. The mitochondrial DNA (mtDNA) D-loop region was sequenced, and the patients of the study group were categorized as MO or IM based on the sequence variations. Univariate and multivariate analyses were used to determine the important clinicopathologic characteristics in the two groups. Results: In the study group, 20 cases were categorized as MO, and 22 as IM, whereas all 20 cases in the control group were characterized as IM. Several factors significantly differed between the IM and MO patients, including hepatitis B e antigen (HBeAg), cumulative tumor size, tumor nodule location, cirrhosis, portal vein and/or microvascular tumor embolus and the histological grade of the primary nodule. Multivariate analysis further demonstrated that cirrhosis and portal vein and/or microvascular tumor thrombus were independent factors differentiating between IM and MO patients. The tumor-free survival time of the MO subjects was significantly longer than that of the IM subjects ($25.7{\pm}4.8$ months vs. $8.9{\pm}3.1$ months, p=0.017). Similarly, the overall survival time of the MO subjects was longer ($31.6{\pm}5.3$ months vs. $15.4{\pm}3.4$ months, p=0.024). The multivariate analysis further demonstrated that the original type (p=0.035) and Child-Pugh grade (p<0.001) were independent predictors of tumor-free survival time. Cirrhosis (p=0.011), original type (p=0.034) and Child-Pugh grade (p<0.001) were independent predictors of overall survival time. Conclusions: HBeAg, cumulative tumor size, tumor nodule location, cirrhosis, portal vein and/or microvascular tumor embolus and histological grade of the primary nodule are important factors for differentiating IM and MO. MO HCC patients might have a favorable outcome compared with IM patients.

• Journal of dental hygiene science
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• v.7 no.1
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• pp.13-20
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• 2007

This study is aimed at providing basic data for measures to prevent dental hygienists who are highly exposed to hepatitis-B virus due to their characteristic working conditions from being infected of it. In order to determine their perception and the extent of their exposure to the risk of infection with hepatitis-B virus, a survey was conducted with questionnaires distributed to 354 dental hygienists who are working at dental offices in Seoul. Gyeongi and Jeolla provincial areas. From the survey, following conclusions could be drawn: 1. Sixty three point seven to 100 percent of them are found to have been vaccinated against hepatitis-B virus as is generally expected from their working environment. 2. Their general characters are found to be statistically significant in terms of vaccinating point of time among those who have been vaccinated. Most respondents are either vaccinated one year or 5 years ago. The completion of 3 requested vaccinations lies in the level of 64.3%~100% depending on the general characters. By age, the best result comes from the age group of 25~29, followed by the groups older than 30 and 20-24 in order (p < 0.05). Formation of antibody belongs to the level of 45%~100% generally. But statistically significant of them is the extremely unhealthy state with 100%, followed by normal, generally healthy, very healthy and not healthy in sequence (p < 0.05). 3. In terms of family's clinical history, it is known that the older (p < 0.01), the more unhealthy (p < 0.01) and the married (p < 0.01), the more possibility of having anamnesis of hepatitis-B virus infection. 4. The level of knowledge about Hepatitis-B virus is shown to be in the extent of 4.39~5.01 out of maximum 8 points in general terms. 5. It is revealed that there are high chances for dental hygienists to get spattered with body matters of patients like blood or sputum on their faces in general characters (87.%~100%). 6. A high rate (75%~100%) of respondents has experienced being shot by needles. The older(p < 0.05) and the longer(p < 0.05) their career, the higher the rate becomes.

• Economic and Environmental Geology
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• v.12 no.2
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• pp.51-73
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• 1979

The zinc-lead deposits at the Yeonhwa I mine were investigated in terms of ore-forming geologic setting, structural style of ore control, geometry of individual orebodies, zoning, paragenesis and chemical composition of skarn minerals, as well as metal grades and ratios of selected orebodies. The Yeonhwa I mine is characterized by a large swarm of chimney type massive orebodies with thin skarn envelopes, boldly developed through a thick sequence of Pungchon Limestone, the overlying Hwajeol Formation, and the underlying Myobong Slate of Cambrian age. Nearly 20 orebodies of similar shape, but of varying size are arranged in a V-shaped pattern with northwest and northeast trends, clearly indicating an outstanding ore control by a conjugate system of fractures with these trends. Important orebodies are the Wolam 1, 2, 3, and 5 orebodies in the west, and the Namsan 1, 2, 3. and 5 orebodies in the east, among others. The Wolam 1 orebody, which was observed from the -360 level through the -240, -120, and 0 levels to the surface outcrops (totaling a vertical height of about 500m), shows a vertical variation in skarn mineralogy, ranging from pyroxene-garnet zone on the lower levels. through pyroxene (without garnet) zone on the intermediate levels, and finally to rhodochrosite vein on the upper levels and surface. Microprobe analyses of pyroxene and garnet on a total of 14 mineral grains revealed that pyroxenes are manganoan salitic in most samples, with downward increase of Fe and Mn, whereas garnets are highly andraditic, containing fractions of subordinate grossular with downward decrease of Fe. This indicates a reverse relationship of Fe-contents between pyroxene and garnet with depth. Ore minerals are major sphalerite, subordinate galena, and minor chalcopyrite. Sulfide gangue minerals include major pyrrhotite, and minor pyrite and marcasite of later age. Two types of variational trends in metal grades and ratios with depth are present on the plots of assay data from the Wolam orebodies: one is a steady upward increase in Pb, Zn, and Pb:Zn ratios, with a terminal decline at the top of orebody: the other is an irregular or sinusoidal change. The former is characteristic of chimney-type orebodies, whereas the latter is of vein· shaped orebodies. The Pb grades show large variations among orebodies and from level to level, whereas the Zn grades are relatively constand or less variable.

• Economic and Environmental Geology
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• v.17 no.2
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• pp.115-139
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• 1984

The Cu-Pb-Zn-Ag hydrothermal vein-type deposits which comprise the Sambong mine occur within calc-alkaline volcanics of the Cretaceous Gyeongsang Basin. The ore mineralization took place through three distinct stages of quartz (I and II stages) and calcite veins (III stage) which fill the pre-existing fault breccia zones. These stages were separated in time by tectonic fracturing and brecciation events. The reflection variations of one mineral depending on mineralization sequence are considered to be resulted from variation in its chemical composition due to different physico-chemical conditions in the hydrothermal system. The reflection power of sphalerite increases with the content of Fe substituted for Zn. Reflectances of the sphalerite grain are lower on (111) than on (100) surface. The spectral profiles depend on the internal reflection color. Sphalerite, showing green, yellow and reddish brown internal reflection, have the highest reflection power at $544m{\mu}$ (green), $593m{\mu}$ (yellow) and $615m{\mu}$ (red) wavelength, respectively. Chalcopyrite is recognized as biaxial negative from the reflectivity data of randomly oriented grains measured at the most sensitivity at $544m{\mu}$. The microindentation hardness against the Fe content (wt. %) for the sphalerite increases to 8.05% Fe and then decreases toward 9.5% Fe content. Vickers hardness of the sphalerite is considerably higher on surface of (100) than on (111). The relationship between Vickers hardness and crystal orientation of the galena was determined to be $VHN_{(111)}$ > $VHN_{(210)}$ > $VHN_{(100)}$. The softer sulfides have the wider variation of the diagonal length in the indentation. Diagonal length in the indentation is pyrite

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.55-66
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• 2018

The cactus habitat in Jeju Island has a phytogeographically specific distribution in the East Asian region, and forms a unique landscape as the only native cactus (Opuntia ficus-indica (L.) Mill.) habitat in Korea. However, there has been no detailed investigation on the distribution of cacti in the habitat and no investigation on the diversity of the mixed composition of plants in the habitats and their correlation with the distribution of cactus populations. This study attempted to investigate the diversity of vascular plants in the Wollyeong-ri cactus habitat and record the actual distribution and trends of cactus distribution. In addition to the distribution characteristics of cacti, we also discuss the characteristics of species reflecting the characteristics of the habitat among the mixed population of plant species, as well as the biological and environmental factors that threaten the maintenance of cactus populations or require management for preservation of cacti. Considering the phenological character, we conducted the field surveys for flora identification six times between June 2015 and September 2017. The Engler classification system was used for the arrangement sequence and names of plants, and the Korean Plant Names Index was adopted for the Korean name of the species. The study results showed that the Wolryung-ri cactus habitat in Jeju Island has the characteristic physiognomy of an area dominated by cactus. For the vascular plants, a total of 125 taxa were identified, including 53 families, 104 genera, 109 species, 15 varieties and 1 forma. Endangered plants specified by the Ministry of Environment were not found. Two species, Cyrtomium falcatum and Asplenium incisum, were identified as the ferns, and no gymnosperms were found. In addition, 123 taxa of angiosperms, 91 taxa of dicotyledones and 32 taxa of monocotyledons were identified. The distributions of cacti were confirmed in 289 meshes corresponding to 59.3% of the total 487 meshes in the cactus protected area, which showed various coverage distributions ranging from 5% to 95%. Most of the meshes where no cacti were found are coastal areas with exposed basalt rocks where the soil depth has not developed or extremely restricted due to repeated waves, or areas where artificial facilities, grasslands, and observation paths have been constructed. On the other hand, there were 71 lattice points in 14.5% of the total area where the cactus showed 70% or higher dominance. Cacti are randomly distributed in these areas. They have adapted to the microhabitat environment and are found to be opportunistically distributed along the growable locations. Considering that the reproduction of cacti in the habitat is mostly dependent on parthenogenesis, the present distribution seems to reflect the potentially distributable regions of cacti in the habitat. Based on the results of field surveys, a management plan for conservation and protection of the protected areas has been proposed.

• Journal of Plant Biotechnology
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• v.41 no.1
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• pp.56-63
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• 2014

Using commercial radish varieties for processing, about 30% of radish was discarded due to the root shape and low purity. To raise the processing ability, we tried to develop a new variety producing H-shaped root. As another characteristic required in variety for processing is high purity, we tried to raise purity using simple sequence repeats (SSR) markers for testing seed purity in every segregating generation. To develop Male-sterile (MS) seeding parent, we crossed commercial variety of 'Gwan dong spring' and 'Gyeo ryong spring'. One elite inbred was selected as recurrent parent for the MS plant. The major horticultural traits of selected inbred line were disease resistance, late bolting, heat resistance and bright green root top color. To develop pollen parent, we crossed commercial variety of 'Tae sang king' and 'Seoul spring'. We used individual selection method to develop H-shaped hard root and disease resistant inbred. In each segregating generation, we selected one plant based on phenotype and the uniformity of selected plant was tested by SSR markers using self-pollinated seeds. In the first segregating generation, 64.6% of sib plants shared the same band in PCR amplification using ACMP-490 primer and 66.7% using cnu-316 primer. The uniformity of segregating generations using ACMP-490 and cnu-316 raised in second generation to 68.8%, 70.8%, respectively; in third generation to 93.8%, 100%; in fourth generation to 93.8%, 100%; in fifth generation to 95.8%, 100%; in sixth generation to 100%, 100%. A novel cross was made using selected MS parent and pollen parent. When we checker the horticultural traits using autumn cultivation, the novel cross variety produced H-shaped root comparing other commercial varieties and produced highly uniform radish. Thus we registered this novel cross variety as 'YR ORE' at 2013 (Registration No. 4550).

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.375-381
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• 2018

The consumption of oats (Avena sativa L.) with high nutritional utility is accelerating due to the increased consumers' demand for functional foods. In Korea, naked oats are used as food, while covered oats are used for animal feed. However, it is difficult to distinguish naked oats from covered oats when the husk is removed from the grains by a special process. The present study was carried out to investigate experimental methods that would be beneficial in the segregation of different types of oats after husk removal. Grain quality-related biochemical compounds were analyzed in a bid to differentiate the oat dehulling characteristics. In addition, 61 SSR markers were examined for genetic relationship and variety identification of oats using five naked and seven covered oat varieties. Results showed that, the contents of protein, lipid, and ${\beta}-glucan$ were not significantly different among the oat varieties and this could not be used as an index for distinguishing oats husk character. However, in the fatty acid composition ratio,, naked oats had a higher ratio of stearic acid (C18:0) and oleic acid (C18:1) than covered oats, and covered oats had a higher ratio of linoleic acid (C18:2) and linoleic acid (C18:3) than naked oats. The assessment of SSR marker genotype revealed that 33 polymorphic bands among 12 oat varieties and 1 variety could be distinguished through the combination of polymorphic markers thus indicating the usability of these markers for variety identification in oats.

• Journal of Intelligence and Information Systems
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• v.24 no.4
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• pp.111-136
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• 2018

In this paper, we propose a methodology to extract answer information about queries from various types of unstructured documents collected from multi-sources existing on web in order to expand knowledge base. The proposed methodology is divided into the following steps. 1) Collect relevant documents from Wikipedia, Naver encyclopedia, and Naver news sources for "subject-predicate" separated queries and classify the proper documents. 2) Determine whether the sentence is suitable for extracting information and derive the confidence. 3) Based on the predicate feature, extract the information in the proper sentence and derive the overall confidence of the information extraction result. In order to evaluate the performance of the information extraction system, we selected 400 queries from the artificial intelligence speaker of SK-Telecom. Compared with the baseline model, it is confirmed that it shows higher performance index than the existing model. The contribution of this study is that we develop a sequence tagging model based on bi-directional LSTM-CRF using the predicate feature of the query, with this we developed a robust model that can maintain high recall performance even in various types of unstructured documents collected from multiple sources. The problem of information extraction for knowledge base extension should take into account heterogeneous characteristics of source-specific document types. The proposed methodology proved to extract information effectively from various types of unstructured documents compared to the baseline model. There is a limitation in previous research that the performance is poor when extracting information about the document type that is different from the training data. In addition, this study can prevent unnecessary information extraction attempts from the documents that do not include the answer information through the process for predicting the suitability of information extraction of documents and sentences before the information extraction step. It is meaningful that we provided a method that precision performance can be maintained even in actual web environment. The information extraction problem for the knowledge base expansion has the characteristic that it can not guarantee whether the document includes the correct answer because it is aimed at the unstructured document existing in the real web. When the question answering is performed on a real web, previous machine reading comprehension studies has a limitation that it shows a low level of precision because it frequently attempts to extract an answer even in a document in which there is no correct answer. The policy that predicts the suitability of document and sentence information extraction is meaningful in that it contributes to maintaining the performance of information extraction even in real web environment. The limitations of this study and future research directions are as follows. First, it is a problem related to data preprocessing. In this study, the unit of knowledge extraction is classified through the morphological analysis based on the open source Konlpy python package, and the information extraction result can be improperly performed because morphological analysis is not performed properly. To enhance the performance of information extraction results, it is necessary to develop an advanced morpheme analyzer. Second, it is a problem of entity ambiguity. The information extraction system of this study can not distinguish the same name that has different intention. If several people with the same name appear in the news, the system may not extract information about the intended query. In future research, it is necessary to take measures to identify the person with the same name. Third, it is a problem of evaluation query data. In this study, we selected 400 of user queries collected from SK Telecom 's interactive artificial intelligent speaker to evaluate the performance of the information extraction system. n this study, we developed evaluation data set using 800 documents (400 questions * 7 articles per question (1 Wikipedia, 3 Naver encyclopedia, 3 Naver news) by judging whether a correct answer is included or not. To ensure the external validity of the study, it is desirable to use more queries to determine the performance of the system. This is a costly activity that must be done manually. Future research needs to evaluate the system for more queries. It is also necessary to develop a Korean benchmark data set of information extraction system for queries from multi-source web documents to build an environment that can evaluate the results more objectively.