• 자원환경지질
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• 제30권6호
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• pp.587-601
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• 1997

This study had three purposes: (1) to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock-soil-plant system; (2) to evaluate the uptake ratios of heavy metals from soils into plants and (3) to assess the chemical speciation of heavy metals in soils. Rock, surface soil and plant samples were collected in the Boeun area underlain by black shales of the Okchon Zone. These samples were analyzed for multi-elements using INAA, ICP-AES and AAS. The maximum abundance of U in black shales is 16 mg/kg and radioactivity counts up to 300 cpm. In particular, Mo, V, Ba, Cd, Pb and U are enriched in black shales. Most of soils derived from black shales show high concentrations of U, As, Mo, Ba, Cu, Cd, Pb, Zn and mean concentrations of As and Mo in soils (20 mg/kg of As and 6.6 mg/kg of Mo) are higher than the permissible level suggested by Kloke (1979). Enrichment index values of soils are calculated and higher than 1.0 in the black shale area with the highest value of 6.4. Mean concentration of Cd in plants is higher than those of Cu, Pb and Zn. The concentration of Cd in plant species decreases in the order of Chinese cabbage > red pepper > soybean=sesame > rice stalk > com > rice grain. The biological absorption coefficients (BAC) in plants are in the order of Cd > Zn=Cu > Pb, which suggests that Cd is more bioavailable to plants than Cu, Pb and Zn. From the results of sequential extraction analysis of soils, relatively high proportion of Cu, Pb and Zn are present as residual fractions whereas that of Cd as non-residual fractions. Cadmuim occurs predominantly as exchangeable/water-acid soluble phase in soils, and Cd is more mobile and bioavailable than Cu, Pb and Zn.

• Asian Journal of Atmospheric Environment
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• 제11권4호
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• pp.330-343
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• 2017

Climate change is an important issue, with many researches examining not only future climatic conditions, but also the interaction of climate and air quality. In this study, a new version of the emissions processing software tool - Python-based PRocessing Operator for Climate and Emission Scenarios (PROCES) - was developed to support climate and atmospheric chemistry modeling studies. PROCES was designed to cover global and regional scale modeling domains, which correspond to GEOS-Chem and CMAQ/CAMx models, respectively. This tool comprises of one main system and two units of external software. One of the external software units for this processing system was developed using the GIS commercial program, which was used to create spatial allocation profiles as an auxiliary database. The SMOKE-Asia emissions modeling system was linked to the main system as an external software, to create model-ready emissions for regional scale air quality modeling. The main system was coded in Python version 2.7, which includes several functions allowing general emissions processing steps, such as emissions interpolation, spatial allocation and chemical speciation, to create model-ready emissions and auxiliary inputs of SMOKE-Asia, as well as user-friendly functions related to emissions analysis, such as verification and visualization. Due to its flexible software architecture, PROCES can be applied to any pregridded emission data, as well as regional inventories. The application results of our new tool for global and regional (East Asia) scale modeling domain under RCP scenario for the years 1995-2006, 2015-2025, and 2040-2055 was quantitatively in good agreement with the reference data of RCPs.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.821-827
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• 2014

An isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) method has been developed and applied to the determination of arsenobetaine (AsB, ${(CH_3)_3}^+AsCH_2COO^-$) from oyster candidate certified reference material (CRM). The exact matching isotope dilution approach was adopted for accurate determination of AsB using $^{13}C_2$-labeled AsB as an internal standard. Efficiencies of different AsB extraction methods were evaluated using a codfish reference material and a simple sonication method was selected as the method of choice for the certification of the oyster candidate CRM. The hydrophilic interaction liquid chromatography (HILIC) combined with electrospray ionization tandem mass spectrometry (ESI/MS/MS) in selected reaction monitoring (SRM) mode was optimized for adequate chromatographic retention and robust quantification of AsB from codfish and oyster samples. By analyzing 12 subsamples taken from each 12 bottles systematically selected from the whole oyster CRM batch, the certified value of AsB was determined as $6.60mg{\cdot}kg^{-1}{\pm}0.31mg{\cdot}kg^{-1}$ and it showed excellent between-bottle homogeneity of less than 0.42%, which is represented by relative standard deviation of 12 bottles from the CRM batch. The major source of uncertainty was the certified value of the AsB standard solution.

• 환경생물
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• 제38권2호
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• pp.248-253
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• 2020

DNA 함량 조사는 진화의 유전적 기작을 예측하여 종분화를 파악하게 한다. 본 연구의 목적은 참전복(Haliotis discus hannai)의 DNA 함량을 측정하고 유세포분석기(flowcytometry)로 고정(fixation) 없이 DNA 함량 측정에 최적인 조직들을 파악하는 것이다. DNA 함량 (pg nucleus^-1)에 있어, 원생생물에 오염된 아가미조직(2.5±0.08)은 3.2±0.02 pg nucleus^-1의 DNA 함량을 보인 근육조직과 외투막조직에 비하여 유의하게 낮았고(p<0.05) standard reference보다도 낮은 반면, 근육조직과 외투막조직은 standard reference보다 높았다. 본 연구 결과들을 고려 시, 참전복에서 고정 없이 유동세포분석에 적절한 조직은 근육과 외투막이며 본 연구에 적용된 고정 과정이 없는 유세포분석법은 참전복 DNA 함량 분석 시 정확하고, 신속한 방법임이 판명되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권8호
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• pp.3681-3686
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• 2014

In this study, we demonstrated selenium (Se) accumulation in Bifidobacterium longum strain (B. longum) and evaluated the effect of Se-enriched B. longum (Se-B. longum) on tumor growth and immune function in tumor-bearing mice. Analysis using high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) revealed that more than 99% of Se in Se-B. longum was organic, the main component of which was selenomethionine (SeMet). In the in vivo experiments, tumor-bearing mice (n=8) were orally administrated with different doses of Se-B. longum alone or combined with cyclophosphamide (CTX). The results showed that the middle and high dose of Se-B. longum significantly inhibited tumor growth. When Se-B. longum and CTX were combined, the antitumor effect was significantly enhanced and the survival time of tumor-bearing mice (n=12) was prolonged. Furthermore, compared with CTX alone, the combination of Se-B. longum and CTX stimulated the activity of natural killer (NK) cells and T lymphocytes, increasing the levels of interleukin-2 (IL-2) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), and the leukocyte count of H22 tumor-bearing mice (n=12).

• Journal of Species Research
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• 제1권1호
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• pp.4-34
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• 2012

Parastenocaris koreana sp. nov. is described based on examination of numerous adult specimens of both sexes from several localities in Korea. Scanning electron micrographs are used to examine intra- and interpopulation variability of micro-characters, in addition to light microscopy. The new species is most closely related to the Japanese P. biwae Miura, 1969, which we redescribe based on newly collected material from the Lake Biwa drainage area. The two species differ in size, relative length of the caudal rami, shape of the anal operculum, shape of the genital double somite, relative length of the inner distal process on the female fifth leg, as well as relative length of the apical setae on the second, third, and fourth legs exopods in both sexes. Detailed examinations of three disjunct populations of P. koreana reveal also some geographical variation, especially in the surface ornamentation of somites, which may indicate some population structuring or even cryptic speciation. Lack of intraspecific variability in the number and position of sensilla on somites, as well as their potential phylogenetic significance, is a novel discovery. Both species examined here belong to the brevipes group, which we redefine to include 20 species from India (including Sri Lanka), Australia, East Asia, Northern Europe, and North America. A key to species of this group is also provided. In order to test the monophyly of the redefined brevipes group with highly disjunct distribution, as well as relationship between different species, a cladistics analysis is performed based on 39 morphological characters and with help of three outgroup taxa. Six equally parsimonious cladograms are generated, all of which show that the ingroup is well defined by at least three synapomorphies. Reconstructed phylogeny questions the previously suggested hypothesis about the origin of this group in South East Asia, with one Australian species showing the most basal position. We speculate that the present distribution of this group may be a combination of ancient vicariance and subsequent dispersal, with a possible origin in the Gondwanaland, in the rift valley between Australia and India.

• Journal of Microbiology and Biotechnology
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• 제28권10호
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• pp.1760-1768
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• 2018

The type strain Bacillus subtilis subsp. subtilis KCTC $3135^T$ was deeply sequenced and annotated, replacing a previous draft genome in this study. The tar and tag genes were involved in synthesizing wall teichoic acids (WTAs), and these genes and their products were previously regarded as the distinguishing difference between B. s. subtilis and B. s. spizizenii. However, a comparative genomic analysis of B. subtilis spp. revealed that both B. s. subtilis and B. s. spizizenii had various types of cell walls. These tar and tag operons were mutually exclusive and the tar genes from B. s. spizizenii were very similar to the genes from non-Bacillus bacteria, unlike the tag genes from B. s. subtilis. The results and previous studies suggest that the tar genes and the tag genes are not inherited after subspecies speciation. The phylogenetic tree based on whole genome sequences showed that each subspecies clearly formed a monophyletic group, while the tree based on tar genes showed that monophyletic groups were formed according to the cell wall type rather than the subspecies. These findings indicate that the tar genes and the presence of ribitol as a cell-wall constituent were not the distinguishing difference between the subspecies of B. subtilis and that the description of subspecies B. s. spizizenii should be updated.

• 자원환경지질
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• 제29권4호
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• pp.495-508
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• 1996

This study had three purposes: (1) to investigate dispersion and enrichment level of potentially toxic elements; (2) to identify uranium-bearing minerals in black shales; and (3) to assess the chemical speciation of heavy metals in soils and sediments. Rock, surface soil and stream sediment samples were collected in the Chungjoo area covered with black shales in Korea. These samples were analyzed for multi-elements using INAA and ICP-AES. The maximum abundance of U in black shales is 56 ppm and radioactivity counts up to 240CPM. Molybdenum, V, Ba, Cu, and Pb are enriched in black shales and most of soils show high concentrations of U, Mo, Ba, Cu, Pb and Zn. Concentrations of potentially toxic elements decrease in the order of mountain soil > farmland soil > paddy soil. Enrichment index of soils and sediments are calculated and higher than 1.0 in the black shale area with the highest value of 6.1. In order to identify U-bearing minerals, electron probe micro analysis was applied, and uraninite and brannerite in black shale were found. Uraninite grains are closely associated with monazite or pyrite with the size of $2{\mu}m$ to $10{\mu}m$ in diameter whereas brannerite occurs as $50{\mu}m$ euhedral grains. With the results of sequential extraction scheme, residual fractions of Cu, Pb and Zn in soils are mainly derived from weathering of black shale but Cu, Pb and Zn in sediments are present as non-residual fractions. Lead is predominantly present as oxidizable phase in soils whereas Zn is in exchageable/water-acid soluble phase in sediments.

• 한국과학교육학회지
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• 제37권4호
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• pp.565-575
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• 2017

이 연구에서는 초등 과학 영재 학생들을 대상으로 자연선택 핵심개념 논변 활동 담화에서 드러난 인식적 이해와 논변활동 수준을 분석하였다. 논변활동에 참여한 학생들은 광역시 소재 영재교육원 6학년 학생 20명이었는데, 그 중 적극적으로 논변활동에 참여한 소집단 중 담화에서 인식적 이해가 드러나며, 개념에 따라 소집단 구성원의 인식적 이해 수준이 서로 달랐던 세 명으로 구성된 소집단을 목적표집하여 그들의 담화를 분석하였다. 담화에서 드러난 인식적 이해의 요소는 본성, 일반성, 정당화, 청중의 범주로 나누어 분석하였으며 논변활동 수준은 논변의 구성과 비평을 중심으로 내재적 인지 부하에 따라 만들어진 논변활동 학습발달과정을 사용하였다. 연구 결과, 학생들의 논변활동에서 드러난 인식적 이해는 자연선택 하위 개념별로 다르게 나타났다. 자연 선택 하위 개념 모두 실천적 인식적 이해의 본성 측면에서는 모두 높게 나타났으나 일반성, 정당화, 청중 범주에서는 높거나 낮았으며, 그 수준이 담화에서 드러나지 않는 경우도 있었다. 지식의 일반성 측면에서 높게 드러난 변이의 유전개념에서 획득형질의 유전에 반대하는 다양한 현상과의 연결은 다양한 아이디어를 생성하여 논변활동 참여를 촉진하는 요소로 활용되어 세 학생 모두 논변활동 수준은 비판 제시 수준으로 나타났다. 하지만, 정당화와 청중 범주에서 실천적 인식적 이해 수준이 낮게 드러난 개념들의 학생의 논변 활동 수준은 그 보다 낮았다. 학생들이 최종 자연선택 핵심 개념인 종분화 개념 논변 시 모두 인식적 이해 수준이 높았던 개념들을 이용하여 종분화 과정을 설명하려 하였으며, 반대로 인식적 이해 수준이 낮았던 개념은 설명 요소로 포함시키지 않았다. 이 연구결과 학생들은 다양한 인식론적 자원을 통해 맥락에 따라 활용되는 인식론적 자원은 다르며 학생들이 왜, 어떻게 인식론적 결정을 하는지에 대한 구체적인 요인들을 분석할 필요성을 제안한다. 인식론적 결정에 영향을 미치는 다양한 요인 분석은 논변 활동의 질과 수준을 높일 수 있는 교수자의 중재 요소가 될 수 있다.

• 식물분류학회지
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• 제37권4호
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• pp.477-502
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• 2007

본 연구에서는 Aconitum alboviolaceum Kom. complex에 속하는 6종 중 한국산 4종(A. alboviolaceum, A. longecassidatum, A. pseudolaeve, A. quelpaertense)을 대상으로 형 태 및 주성분분석(Principal Components Analysis)과 엽록체 DNA psbA-trnH IGS, trnL intron 및 tmL-trnF IGS 구간의 분석을 통해 각 분류군의 타당성을 검토하고 그 한계 및 분류학적 위치를 명확히 설정하고자 하였다. 형태분석 결과, 기존에 보고되었던 주요 식별형질에서 형태변이가 종 및 개체군 수준에서 복잡한 형태로 나타났으며 주성분분석 결과 각 분류군들은 종 및 개체군 수준에서 유집 되지 않고 연속적으로 혼합된 양상을 보였다. 염기서열 분석 결과, l0개의 염기치환과 3개의 indel이 관찰되었고, 이를 통해 얻어진 neighbor-joining tree에서 나타난 4개의 그룹은 종 및 개체군을 반영하지 않았다. 따라서, 본 연구에서는 complex 내 분류군들에 관한 기존의 형태형질에 근거한 분류체계를 지지하지 않으며, 이들 분류군 간의 분류체계에 대한 재고가 필요하다고 본다.