• 한국환경보건학회지
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• 제37권6호
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• pp.440-449
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• 2011

Objectives: This study was designed to determine the levels of polybrominated diphenyl ethers (PBDEs) in breast milk and to evaluate the relations with factors affecting these levels. Methods: The congener levels of PBDE in 22 samples of breast milk were analyzed using a high resolution gas chromatograph with a high resolution mass detector. In accordance with our standard operating procedures, the recoveries of internal standards had to range between 68% and 118%. Since the distribution of PBDE concentrations is close to log-normal, the data were logarithmically transformed before analysis. Test subjects were healthy primipara and multipara mothers with a mean age of 32 (SD = 2.7) in 2006. Results: Seven PBDE congeners (BDE-28, 47, 99, 100, 153, 154, and 183) were detected and identified in all of the pooled breast milk samples, indicating widespread contamination from PBDEs in the environment in Korea. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged from 0.84-13.1 ng/g lipid with median and geometric mean levels of 2.6 ng/g lipid and 2.74 ng/g lipid, respectively. PBDE congeners 47, 99 and 153 markedly predominated and accounted for about 75% of the amount of the PBDE congeners analyzed. BDE-47 was the dominant congener in most samples, whereas BDE-153 was predominant in a few (n = 7/22). BDE-47 was highly correlated with total PBDEs (r = 0.987, p < 0.01). In analyses of the differences of the means of log transformed breast milk PBDE levels for groups of potential covariates, only breast milk BDE-47 and BDE-99 levels were significantly associated with fish (p < 0.05) and meat consumption (p < 0.01). However, we did not find significant correlations between PBDE levels and maternal age, body mass index (BMI), parity, job presence and smoking status. Conclusions: Our findings are mainly limited due to the small sampling size and low doses of PBDEs exposure. Background and human exposure data of PBDEs is lacking, and longitudinal investigations into the environment and biota are encouraged to determine the health impact on future populations in Korea.

• Toxicological Research
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• 제31권3호
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• pp.255-264
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• 2015

Heterocyclic amines (HCAs) and acrylamide are unintended hazardous substances generated by heating or processing of foods and are known as carcinogenic and mutagenic agents by the animal experiments. A simple method was established for a rapid and accurate determination of 12 types of HCAs (IQ, MeIQ, Glu-P-1, Glu-P-2, MeIQx, Trp-P-1, Trp-P-2, PhIP, $A{\alpha}C$, $MeA{\alpha}C$, Harman and Norharman) and acrylamide in three food matrices (non-fat liquid, non-fat solid and fat solid) by isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS). In every sample, a mixture of internal standards including $IQ-d_3$, $MeIQx-d_3$, $PhIP-d_3$, $Trp-P-2-^{13}C_2-^{15}N$ and $MeA{\alpha}C-d_3$ was spiked for quantification of HCAs and $^{13}C_3$-acrylamide was also spiked for the analysis of acrylamide. HCAs and acrylamide in sample were extracted with acetonitrile and water, respectively, and then two solid-phase extraction cartridges, ChemElut: HLB for HCAs and Accucat: HLB for acrylamide, were used for efficiently removing interferences such as pigment, lipid, polar, nonpolar and ionic compounds. Established method was validated in terms of recovery, accuracy, precision, limit of detection, limit of quantitation, and linearity. This method showed good precision (RSD < 20%), accuracy (71.8~119.1%) and recovery (66.0~118.9%). The detection limits were < 3.1 ng/g for all analytes. The correlation coefficients for all the HCAs and acrylamide were > 0.995, showing excellent linearity. These methods for the detection of HCAs and acrylamide by LC-MS/MS were applied to real samples and were successfully used for quantitative monitoring in the total diet study and this can be applied to risk assessment in various food matrices.

• 방사성폐기물학회지
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• 제4권3호
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• pp.275-284
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• 2006

실제 드럼 내에 존재하는 핵종으로부터 방출되는 감마선을 외부에서 측정하여 그로부터 드럼 내 핵종의 양을 정확하게 분석하기 위해서는 먼저 적절한 교정표준의 선택과 드럼 내 매질의 밀도와 핵종의 분포에 대한 감마선 감쇠보정이 반드시 필요하다. 본 연구에서는 드림 내 핵종의 분석을 위하여 밀도가 다른 두 개의 모델드럼을 이용하였으며 전송선원으로써는 $^{152}Eu$(10 mCi), 표준선원으로는 혼합선원($^{133}Ba,\;^{137}Cs,\;^{60}Co$)을 이용하였다. 그리고 드럼과 검출기 사이의 거리를 달리하면서 모델드럼 내의 표준선원으로부터 나오는 감마선을 계측하여, 감쇠보정이 되지 않은 이 측정값에 3 종류의 감마선 감쇠보정을 각각 수행하였다. 그 결과 밀도가 낮은 드럼에서의 오차는 10 % 이하이었고, 밀도가 높은 드럼에서의 오차는 25 % 이하이었다. 또한 드럼과 검출기사이의 거리가 근거리(70 cm, 드림구획 : 10 segments)일 때, 오차는 원거리(90 cm, 드럼구획 : 8 segments)에서의 오차보다는 낮았는데 이는 상대적으로 1 segment에 대한 부피차이에 기인한 밀도 측정오차가 낮고 감마선의 산란이 낮았기 때문이다.

• Journal of Ginseng Research
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• 제37권1호
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• pp.124-134
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• 2013

The authentication of the physico-chemical properties of ginsenosides reference materials as well as qualitative and quantitative batch analytical data based on validated analytical procedures is a prerequisite for certifying good manufacturing practice (GMP). Ginsenoside Rb1 and Rg1, representing protopanaxadiol and protopanaxatriol ginsenosides, respectively, are accepted as marker substances in quality control standards worldwide. However, the current analytical methods for these two compounds recommended by Korean, Chinese, European, and Japanese pharmacopoeia do not apply to red ginseng preparations, particularly the extract, because of the relatively low content of the two agents in red ginseng compared to white ginseng. In manufacturing fresh ginseng into red ginseng products, ginseng roots are exposed to a high temperature for many hours, and the naturally occurring ginsenoside Rb1 and Rg1 are converted to artifact ginsenosides such as Rg3, Rg5, Rh1, and Rh2 during the heating process. The analysis of ginsenosides in commercially available ginseng products in Korea led us to propose the inclusion of the (20S)- and (20R)-ginsenoside Rg3, including ginsenoside Rb1 and Rg1, as additional reference materials for ginseng preparations. (20S)- and (20R)-ginsenoside Rg3 were isolated by Diaion HP-20 adsorption chromatography, silica gel flash chromatography, recrystallization, and preparative HPLC. HPLC fractions corresponding to those two ginsenosides were recrystallized in appropriate solvents for the analysis of physico-chemical properties. Documentation of those isolated ginsenosides was achieved according to the method proposed by Gaedcke and Steinhoff. The ginsenosides were subjected to analyses of their general characteristics, identification, purity, content quantification, and mass balance tests. The isolated ginsenosides showed 100% purity when determined by the three HPLC systems. Also, the water content was found to be 0.534% for (20S)-Rg3 and 0.920% for (20R)-Rg3, meaning that the net mass balances for (20S)-Rg3 and (20R)-Rg3 were 99.466% and 99.080%, respectively. From these results, we could assess and propose a full spectrum of physico-chemical properties of (20S)- and (20R)-ginsenoside Rg3 as standard reference materials for GMP-based quality control.

• 한국언론정보학보
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• 제45권
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• pp.463-495
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• 2009

미국 사회에서 1980년대에 시작된 시민저널리즘(civic journalism)이 한국에서는 2000년대에 들어와서야 그 자리를 잡고 활성화되기 시작했다. 기성 저널리즘의 구조적인 문제점들을 보완하기 위해 태동한 대안 저널리즘으로서의 시민저널리즘은 증가하는 온라인 시민기자와 온라인 뉴스 미디어 확산에 의해 새로운 국면을 맞이하고 있는 실정이다. 이에 따라, 두 나라의 시민저널리즘 양상과 그 실천에 있어서의 시민 영향력이 몇몇의 요인에 따라 유의미하게 차이를 드러낸다는 사실에 주목하며 본 연구에서는 그 요인들을 찾아내고 두 나라의 온라인 시민저널리즘을 실증적으로 비교 분석하고자 한다. 이러한 목적 하에 미국의 CNN "iReport", 한국의 "오마이뉴스"라는 양국의 대표적 온라인 시민저널리즘을 다음과 같은 4가지 측면에서 분석하였다: 탈객관주의 정도, 사회 문제에 대한 해결책 모색, 기사의 생산과 소비에 미치는 시민의 영향력 정도. 그 결과로, 미국의 시민저널리즘에서는 전통적인 저널리즘의 객관주의로부터 벗어난 경우가 많고, 사회 문제에 대한 대안 및 해결책 모색과 시민 기자의 활용 정도에 있어서 한국의 시민저널리즘보다 앞서 있다는 점을 알 수 있었다. 또한 기사 의제 설정에 있어서의 시민 의견 반영 정도나 생산된 기사에 대한 시민 참여 및 영향력에 있어서도 한국의 시민저널리즘보다 발전된 모습을 보이고 있었다. 그에 반해, 한국의 시민저널리즘은 기사 의제 설정에 있어서의 여론 조사 반영에 있어서만 미국의 저널리즘보다 앞서 있었고, 정부와 관련된 특정 이슈에 대한 기사에 대해서만 시민의 영향력 이 미치는 특징을 나타냈다.

• Wind and Structures
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• 제31권2호
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• pp.103-142
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• 2020

One of the next frontiers in structural wind engineering is the design of tall buildings using performance-based approaches. Currently, tall buildings are being designed using provisions in the building codes and standards to meet an acceptable level of public safety and serviceability. However, recent studies in wind and earthquake engineering have highlighted the conceptual and practical limitations of the code-oriented design methods. Performance-based wind design (PBWD) is the logical extension of the current wind design approaches to overcome these limitations. Towards the development of PBWD, in this paper, we systematically review the advances made in this field, highlight the research gaps, and provide a basis for future research. Initially, the anatomy of the Wind Loading Chain is presented, in which emphasis was given to the early works of Alan G. Davenport. Next, the current state of practice to design tall buildings for wind load is presented, and its limitations are highlighted. Following this, we critically review the state of development of PBWD. Our review on PBWD covers the existing design frameworks and studies conducted on the nonlinear response of structures under wind loads. Thereafter, to provide a basis for future research, the nonlinear response of simple yielding systems under long-duration turbulent wind loads is studied in two phases. The first phase investigates the issue of damage accumulation in conventional structural systems characterized by elastic-plastic, bilinear, pinching, degrading, and deteriorating hysteretic models. The second phase introduces methods to develop new performance objectives for PBWD based on joint peak and residual deformation demands. In this context, the utility of multi-variate demand modeling using copulas and kernel density estimation techniques is presented. This paper also presents joined fragility curves based on the results of incremental dynamic analysis. Subsequently, the efficiency of tuned mass dampers and self-centering systems in controlling the accumulation of damage in wind-excited structural systems are investigated. The role and the need for explicit modeling of uncertainties in PBWD are also discussed with a case study example. Lastly, two unified PBWD frameworks are proposed by adapting and revisiting the Wind Loading Chain. This paper concludes with a summary and a proposal for future research.

• 한국항해학회지
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• 제19권2호
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• pp.77-97
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• 1995

The protection of the marine environment is one of the main international legal problems in recent years. In parallel with the industrial development, a great quantity of chemical materials were used and in consequence, mass transportation of oil and other dangerous materials was required on the one hand, and discharge of industrial wasters drew also the attention on the other hand. Furthermore, oil tankers accidents, mass use of nuclear materials, sea-bed exploration and exploitation stimulated further deep human concern on the marine environment. The expansion of international concern to new and more dangerous sources of marine pollution regarded more strict and legal control on the Oil Tanker(DWT 95, 000tons, Cb=0.805) model. Calculation results are compared to the international, especially regional level. In particular, this study is concerned with the preservation of the Northeast Asian Seas surrounded by Japan, the Russian Far East, South Korea, North Korea, China and Taiwan. These adjacent countries must intensify cooperation regarding the prevention, reduction and control of the contamination of the sea. And this cooperation between the States concerned should, as much as possible, be aimed at maximizing the effectiveness of measures to prevent or abate transboundary environmental pollution. To achieve this purpose, States concerned should be imposed upon duties such as duty to assess the environmental impact, duty to inform, duty to consult and duty to assist on the basis of general principle of international law, international customary law and other various resolutions of international bodies. Depending on the nature and extent of actual or potential transboundary pollution with the use of a natural resource or the environment in general the establishment of some form of institutionalized cooperation between the States concerned may become useful or indispensable. The functions of this Organization are, inter alia, to keep the implementation of the Convention and the protocals under continuous observation, to make recommendations on regional or sub-regional rules and standards to be elaborated and on measures to be taken by the Contracting Parties, to be notified of any grave and imminent danger from pollution or threat of pollution by the Contracting Parties and to promote in close cooperation with appropriate governmental bodies additional measures to protect the marine environment of the Northeast Asian Seas, and so on. Above mentioned countries, first of all, are located within the Northeast Asian Seas geographically and, therefore, take responsibilities of preserving the clean sea against marine interferences regardless of any difference of the social, political and economic systems. They must be followed under the UNCLOS and other marine conventions. Under the present circumstances, Northeast Asian Seas will become dead seas in case that there is no instant and prompt action against pollution. Hence we have an absolute obligation to promote the development of the mandatory international environmental law, which in turn can faciliate more effective implementation of the regional cooperation by the neighbouring states within this area.

• 한국언론정보학보
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• 제59권
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• pp.31-49
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• 2012

디지털 미디어 기술 발달에 따라 언론인의 직업 규범과 가치가 어떻게 변하고 있는 지를 탐구하는 것이 이 논문의 목적이다. 먼저, 19세기 말 이래 확립된 객관주의, 전문직주의 언론 규범이 새로운 미디어 생태계에서 어떤 변화의 압력을 받고 있는 지를 파악했다. 미디어 환경의 변화는 직업 언론인의 직무 수행에 $\triangle$ 인식론 측면 $\triangle$ 전문직 정체성의 측면 $\triangle$ 독자와의 상호작용 측면에서 변화를 주고 있는 것으로 나타났다. 이어 한국의 역사적 사회적 맥락에서 형성돼 공유되고 있는 언론 규범에 이런 일반적인 변화가 어떻게 투영되고 있는지를 중견 언론인들을 심층 인터뷰 해 조사했다. 인터뷰에 앞서 언론인들로 부터 '기자 정신'의 역할 모델로 인정받는 리영희 선생(1929~2010)의 언론사상을 도출해 비교의 준거로 활용했다. 즉, 이 연구는 $\triangle$실증적 글쓰기를 통한 실체적 진실 추구 $\triangle$전문성에의 열정 $\triangle$독자(민중) 와의 상호교육 등 리영희의 언론 정신으로 상징되는 한국적 언론 규범이 현재의 미디어 환경에서 어떻게 변화해 가고 있는 지를 살펴보는 탐색적 연구이다. 연구결과, 미디어 환경 변화에도 불구하고 언론인들은 실체적 진실추구, 전문성 추구, 심층 탐사보도 등 리영희의 언론정신으로 상징되는 전통 저널리즘의 규범과 가치가 직무 수행에서 여전히 중요한 지침이 된다고 보았다. 또 이런 정신이 현재 한국 저널리즘이 봉착한 위기를 극복하는 데도 긴요하다고 인식하고 있었다. 다만, 언론인들은 디지털 시대에는 이런 저널리즘의 가치를 열린 자세로 수용자와 밀접히 상호작용 함으로써 성취해야 한다고 인식하고 있었다. 진실을 가려 내 제시하는 '판별자'의 역할, 시민저널리스트와 전문가 블로거의 자원을 폭넓게 활용해 뉴스를 생산하는 '네트워크 연결점', 수많은 정보를 엮고 정리하는 '뉴스 코디네이터' 등으로 역할을 확장하는 등 새로운 미디어 기술이 제공하는 환경 변화에 능동적으로 대처해야 할 것으로 지적됐다.

• 분석과학
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• 제13권4호
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• pp.504-510
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• 2000

Glycyrrhizin은 감초(Glycyrrhizae Radix)의 주성분으로써 항궤양, 항염증, 항알러지, 진해작용을 하는 것으로 알려져 있으며 glycyrrhetinic acid에 2당류가 연결된 매우 hydrophilic하고 분자량이 큰(mw=822.92) 물질이다. 본 연구에서는 on-line high performance liquid chromatography (HPLC)/electrospray ionization (ESI)- mass spectrometery (MS)를 이용하여 각종 glycyrrhizin 표준품들의 불순물들에 대한 구조 규명을 하였다. 사용한 HPLC column은 $C_{18}$($3.9{\times}300mm$, $10{\mu}m$)이었으며 이동상은 acetic acid/$H_2O$(1:15):acetonitrile=3:2를 0.8ml/min으로 흘려주었고 용출물을 post-column splitter를 사용하여 50:1로 split시켜서 ESI-MS에 주입하였다. ESI-MS는 negative mode이었으며 CapEx voltage는 100 V에서 각 불순물들의 분자량이 측정되었고 구조규명을 위하여 CapEx voltage를 80-300 V까지 변화시켜주는 CID (collision induced dissoclation) 기법을 사용함으로써 fragment를 얻을 수 있었고 이를 바탕으로 구조규명을 하였다. 주요 불순물의 구조는 glycyrrhetic acid moiety에 수산화기(-OH)가 붙은 형태와 glycyrrhetic acid moiety의 12번 위치에서 환원이 일어난 형태 이었다. 표준품의 순도는 약 90% 정도이었다.

• 대한임상검사과학회지
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• 제51권1호
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• pp.50-56
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• 2019

본 연구는 성인 남성을 대상으로 체질량지수로 분류한 비만 유형에 따른 혈청 GGT와 요산농도의 차이와 관련성을 확인하고자 하였다. 2017년 1월부터 2018년 8월까지 경기지역 종합병원의 건강검진센터를 내원하여 건강검진을 실시한 20세 이상 성인 남성 14,283명을 대상으로 하였다. 비만 기준은 아시아-태평양지역 기준을 적용하였으며, 복부비만은 남성의 허리둘레 90 cm이상을 기준치로 정의하였다. 남성 대상자의 혈청 요산농도 상승은 7.0 mg/dL 이상, 혈청 GGT 상승은 56 IU/L 이상으로 정의하였다. 본 연구결과 혈청 GGT와 요산농도는 정상체중군보다 과체중과 비만군에서 높았으며, 비만군에서는 복부비만을 동반한 경우 혈청 GGT ($53.26{\pm}49.67IU/L$ vs $67.66{\pm}60.16IU/L$) 및 요산농도($6.22{\pm}1.26mg/dL$ vs $6.38{\pm}1.40mg/dL$)가 유의하게 높았다. 그러나 저체중군과는 차이가 없었다. 또한 과체중과 비만군은 정상체중군보다 혈청 GGT 상승과 고요산혈증의 위험이 높게 나타났으나, 저체중은 혈청 GGT 상승과 고요산혈증에 영향을 미치지 않는 것으로 나타났다. 따라서 성인 남성의 과체중 및 비만을 평가하는데 혈청 GGT와 요산이 유용하다고 판단된다.