• 한국물환경학회지
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• 제35권6호
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• pp.510-519
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• 2019

The 'Stable Isotope Analysis in R' (SIAR), one of the Bayesian mixing models for stable isotopes, has been proven to be useful for source apportionment of nitrates in rivers. In this study, the contribution ratios of nitrate sources were quantified by using the SIAR based on nitrogen and oxygen stable isotope measurements in the Yeongsan River. From the measurements, it was found that the values of δ¹⁵N-NO₃ and δ¹⁸O-NO₃ ranged from -8.2 ‰ to +13.4 ‰ and from +2.2 ‰ to +9.8 ‰, respectively. We further analyzed the contribution ratios of the five nitrate sources by using the SIAR. From the modeling results, the main nitrate source was found to be soil N (29.3 %), followed by sewage (26.7 %), manure (19.6 %), chemical fertilizer (17.9 %) and precipitation (6.3 %). From the results, it was found that the anthropogenic sources, i.e., sewage, manure and chemical fertilizer contribute 64.2% of the total nitrate inflow from the watershed. Due to the significant correlation of δ¹⁵N-NO₃ and lnNO₃^- in this study, the fractionation factors reflecting the biogeochemical processes of stable isotope ratios could be directly obtained. This may make the contribution ratios obtained in this study more precise. The fractionation factors were identified as +3.64 ± 0.91 ‰ for δ¹⁵N-NO₃ (p<0.01) and -5.67 ± 1.73 ‰ for δ¹⁸O-NO₃(p<0.01), respectively, and were applied in using the SIAR. The study showed that the stable isotope method using the SIAR could be applied to quantitatively calculate the contribution ratios of nitrate sources in the Yeongsan River.

• 생태와환경
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• 제49권4호
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• pp.279-288
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• 2016

탄소와 질소 안정동위원소비를 이용한 먹이망 구조 해석 기법은 수생태계 연구에서 폭 넓게 활용되고 있으며, 먹이원의 정량적 기여율을 분석하는 믹싱모델에 적용될 수 있다. 본 연구에서는 Bayesian 모델을 이용한 믹싱모델의 적용이 가능한 통계 패키지(R, SIAR package)의 사용방법을 제시하고, 사용 예로 저수지 및 메소코즘 배양조에서의 동물플랑크톤과 먹이원의 탄소, 질소 안정동위원소비를 이용한 섭식 성향 분석 방법 및 결과를 제시하였다. 분석 결과, 국내 저수지 및 대형하천 등에서 주로 우점하는 Daphnia galeata는 소형의 POM (<$50{\mu}m$)을 주로 섭식하는 것으로 나타나, 부영양화된 환경에서 녹조 발생시 먹이로의 활용이 용이하지 않은 것으로 나타났다. 논 생태계 등에서 빈번히 출현하는 패충류의 경우 D. galeata와 유사한 섭식 성향을 나타내었다. 반면 습지 등에서 주로 출현하는 Simocephalus vetulus의 경우, 부착성 POM이 아닌 부유성 POM을 주로 섭식하며 Microcystis를 포함하는 대형의 POM (>$50{\mu}m$)을 섭식하는 것으로 분석되었다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권6호
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• pp.2187-2191
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• 2015

Background: Protrusive structures formed by migrating and invading cells are termed lamellipodia, filopodia, invadopodia and podosomes. Lamellipodia and filopodia appear on the leading edges of migrating cells and function to command the direction of the migrating cells. Invadopodia and podosomes are special F-actin-rich matrix-degrading structures that arise on the ventral surface of the cell membrane. Invadopodia are found in a variety of carcinomatous cells including squamous cell carcinoma of head and neck region whereas podosomes are found in normal highly motile cells of mesenchymal and myelomonocytic lineage. Invadopodia-associated protein markers consisted of 129 proteins belonging to different functional classes including WASP, NWASP, cortactin, Src kinase, Arp 2/3 complex, MT1-MMP and F-actin. To date, our current understanding on the role(s) of these regulators of actin dynamics in tumors of the orofacial region indicates that upregulation of these proteins promotes invasion and metastasis in oral squamous cell carcinoma, is associated with poor/worst prognostic outcome in laryngeal cancers, contributes to the persistent growth and metastasis characteristics of salivary gland adenoid cystic carcinoma, is a significant predictor of increased cancer risk in oral mucosal premalignant lesions and enhances local invasiveness in jawbone ameloblastomas.

• 해양환경안전학회지
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• 제26권5호
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• pp.493-505
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• 2020

본 연구는 2019년 8월 한반도 주변해역(동해, 서해, 남해, 동중국해)에서 탄소 및 질소 안정동위원소 기법을 활용하여 하위영양 단계에서의 먹이망 구조를 파악하였다. 입자성 유기물(POM)의 δ¹³C 범위는 -26.18 ~ 20.61 ‰, δ¹⁵N 범위는 5.36 ~ 15.20 ‰의 넓은 범위를 보였다. POM과 각 생물별 개체군 사이의 δ¹³C 분별작용의 결과는 대부분 micro-POM을 섭식하는 것으로 확인하였으나 해역 간 차이를 보였다. 각 생물별 영양단계는 chaetognaths (3.40±0.61)가 가장 높은 영양단계에 있음을 확인하였다. 동위원소 혼합모델을 적용한 결과에서 chaetognaths의 먹이원으로 copepods (13 ~ 48 %)와 euphausiids (20 ~ 51 %)가 가장 높은 기여도를 나타냈다. 본 연구결과 각 해역별 먹이원의 제한적 공급 및 다양성의 차이가 먹이망 구조 및 각 생물별 동위원소 비에 영향을 미친 것으로 판단된다.

• 대한수학회논문집
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• 제34권1호
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• pp.1-16
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• 2019

Let a, b, P, and Q be real numbers with $PQ{\neq}0$ and $(a,b){\neq}(0,0)$. The Horadam sequence $\{W_n\}$ is defined by $W_0=a$, $W_1=b$ and $W_n=PW_{n-1}+QW_{n-2}$ for $n{\geq}2$. Let the sequence $\{X_n\}$ be defined by $X_n=W_{n+1}+QW_{n-1}$. In this study, we obtain some new identities between the Horadam sequence $\{W_n\}$ and the sequence $\{X_n\}$. By the help of these identities, we show that Diophantine equations such as $$x^2-Pxy-y^2={\pm}(b^2-Pab-a^2)(P^2+4),\\x^2-Pxy+y^2=-(b^2-Pab+a^2)(P^2-4),\\x^2-(P^2+4)y^2={\pm}4(b^2-Pab-a^2),$$ and $$x^2-(P^2-4)y^2=4(b^2-Pab+a^2)$$ have infinitely many integer solutions x and y, where a, b, and P are integers. Lastly, we make an application of the sequences $\{W_n\}$ and $\{X_n\}$ to trigonometric functions and get some new angle addition formulas such as $${\sin}\;r{\theta}\;{\sin}(m+n+r){\theta}={\sin}(m+r){\theta}\;{\sin}(n+r){\theta}-{\sin}\;m{\theta}\;{\sin}\;n{\theta},\\{\cos}\;r{\theta}\;{\cos}(m+n+r){\theta}={\cos}(m+r){\theta}\;{\cos}(n+r){\theta}-{\sin}\;m{\theta}\;{\sin}\;n{\theta},$$ and $${\cos}\;r{\theta}\;{\sin}(m+n){\theta}={\cos}(n+r){\theta}\;{\sin}\;m{\theta}+{\cos}(m-r){\theta}\;{\sin}\;n{\theta}$$.

• 환경영향평가
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• 제14권5호
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• pp.347-353
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• 2005

The risk assessment is the qualitative or quantitative evaluation of the risk posed to human health and the environment by the actual or potential presence or release of hazardous substances, pollutants or contaminants. The environmental impact assessment (EIA) is assessed by the environmental criteria, and risk assessment is assessed by the risk rate. Risk rate based on dose-response values may not be easy to apply on regulatory basis like EIA for uncertainty. Internationally there is an example of OECD program. Risk assessment of High Production Volume (HPV) Chemicals has started since the OECD Program with the 1990 Council Act on the Co-operative Investigation and Risk Reduction of Existing Chemicals. These HPV chemicals include all chemicals produced or imported at levels greater than 1,000 tonnes per year in at least one Member country or in the European Union region. The SIDS called the Screening Information Data Set is regarded as the minimum information needed to assess an HPV chemical to determine whether any further work should be carried out or not. All the data elements of SIDS including assessment for environment and health are prepared as three formats of the full SIDS Dossier, the SIDS Initial Assessment Report (SIAR), and the SIDS Initial Assessment Profile (SIAP) of an HPV chemical. In 1998 the global chemical industry through the International Council of Chemical Associations (ICCA) has joined to work with OECD. The OECD has assessed approximately 1,000 chemicals from 1991 through 2004 with ICCA. Till the February of 2005, 592 chemicals of those chemicals completed SIDS reports. Member countries have been targeted the goal of 1,000 new chemicals from 2005 to 2010 and Korea shared 36 chemicals from the 1,000 new chemicals. Currently Korea has completed SIDS reports of 7 chemicals among sponsored 24 chemicals. In conclusion SIDS project will be linked to national program for outputs application with more reliable production. Both the OECD and industry will carry out their commitment to complete assessments for more and the remaining chemicals assessment. The major outputs will contribute to cope with international chemical management.