• Environmental Analysis Health and Toxicology
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• 제18권2호
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• pp.95-100
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• 2003

본 연구는 환경호르몬(endocrine disruptors)으로 분류되었으며, 제초제로 널리 사용되었던 Dichlorodiphenyltrichloroethane(DDT)가 설치류의 생식세포 중 Leydig 세포의 testosterone(T)생성억제 및 그 관련 작용메카니즘을 규명코자 수행되었다. 먼저 흰쥐의 웅성 생식세포주인 R2C세포에 T의 양 및 aromatase 활성도를 radio immunoassay (RIA)방법을 이용하여 측정하였다. 그 결과 R2C 세포에 황체형성호르몬(LH)를 처리하여 testosterone생성을 증가시킨 후, DDT를 처리한 군들은 대조군에 비하여 농도 의존적으로 T의 양은 감소하였으며, aromatase 활성도는 증가하였다. 또한 DDT자체만 처리한 군에서도 대조군에 비하여 testosterone의 생성이 감소하였다. 이러한 aromatase활성 증가가 estradiol receptor(ER)와의 상호 관련성을 확인하기 위해 ER antagonist인 ICI 182.780를 처리한 후 T의 양 및 aromatase 활성도를 측정한 결과 DDT에 의해 증가된 aromatase활성도가 ICI 182.780에 의해 다시 감소됨을 확인하였다. 또한 DDT에 의해 감소된 T의 양도 ICI 182.780에 의해 다시 회복되었다. In vivo실험으로 흰쥐에 DDT를 직접 투여한 후 정소 내 성 호르몬들을 측정해 본 결과 T의 양은 유의성 있게 감소하였으며, estradiol(E$_2$)의 양은 증가하였으며, aromatase 활성도도 감소하였다. 이러한 결과를 종합해 볼 때 DDT는 aromatase를 감소시키고, 이렇게 감소된 aromatase에 의해 testosterone 생성량을 억제하고, 이러한 DDT의 aromatase의 감소는 ER을 경유하는 것으로 추정할 수 있다.

• Journal of Animal Science and Technology
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• 제48권4호
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• pp.623-636
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• 2006

생명과학분야 65개의 국내 학술지에 게재된 2004년도 논문 6,161편의 연구 형태 및 특성을 서지학적 방법으로 분석하였다. 조사분석 대상 논문의 전체 공저자수는 29,759명이었으며 논문 1편당 평균 공저자수는 4.8명으로 나타났다. 이들 국내 학술지 게재 논문중에서 4인 이상이 참여하여 수행된 공동연구 논문은 전체 63.4%이었으나 CNS에 게재된 생명과학분야 4인 이상 공저자 논문비중 88.9%보다 25.5% 포인트 이상 공동연구 비율이 낮은 것으로 분석되었다. 국내 학술지 게재논문의 공동연구 유형은 대학－대학간 공동연구논문이 19.9%로 가장 비중이 큰 것으로 분석되었으나, CNS 게재논문은 대학－연구소간 공동연구 비율이 48.2%로 가장 비중이 큰 것으로 나타났다.

• 한국과학교육학회지
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• 제31권3호
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• pp.455-474
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• 2011

The purpose of this study is to explore the ways in which scientists reflect on the scientific practices, based on the premise that reflection is one of key elements for shaping scientific identities. This paper specifically considers scientists' reflections as the processes in which their senses of ethical issues and the value of science are articulated. To do so, the study developed a narrative inquiry for exploring the value of scientists' stories. Fourteen professional scientists' stories were collected in the context of the stem cell research, in ways that foreground their reflections on current scientific practices and the surrounding socio-cultural conditions. As for ethical issues, scientists' stories were analysed in terms of four claims regarding the themes of bioethics, integrity, scientific issues and communication. Furthermore, scientists' reflections on the value of science were analysed in relation to the elements of nature of science. Based on the results, discussion focused on the value of science stories as an instrument with which to guide students into the enculturation in the practices of scientific culture.

• Journal of the Korean Wood Science and Technology
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• 제35권2호
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• pp.1-8
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• 2007

Frost ring formed in the secondary xylem of Pinus radiata was examined using various microscopic techniques. Cell walls in a frost ring were poorly developed, lacking in the proportion of wall components. Formation of secondary cell wall was imperfect and thickness of secondary wall was varied. Cytochemical examinations provided the evidence that the synthesis of structural polysaccharides and lignin was inhibited, resulting in the malformation of secondary cell walls. Judging by the highly irregular nature of the cell wall, it appears that cellulosic/hemicellulosic framework was affected and the template for lignification by frost.

• BMB Reports
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• 제46권4호
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• pp.219-224
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• 2013

The cell-fate specification of the anchor cell (AC) and a ventral uterine precursor cell (VU) in Caenorhabditis elegans is initiated by a stochastic interaction between LIN-12/Notch receptor and LAG-2/Delta ligand in two neighboring Z1.ppp and Z4.aaa cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expressions of lin-12 in VU and lag-2 in the AC, through a feedback mechanism of unknown nature. Here we show that the expression pattern of lag-1/CSL, a transcriptional repressor itself that turns into an activator upon binding of the intracellular domain of Notch, overlaps with that of lin-12. Site-directed mutagenesis of LAG-1 binding sites in lag-1 maintains its expression in the AC, and eliminates it in the VU. Thus, AC/VU cell-fate specification appears to involve direct regulation of lag-1 expression by the LAG-1 protein, activating its transcription in VU cells, but repressing it in the AC.

• 농업과학연구
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• 제38권2호
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• pp.315-324
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• 2011

Riparian vegetation distribution patterns and diversity relative to various fluvial geomorphic channel patterns, stream bank stabilization methods, and stream flow processes are described and interpreted for selected nature-friendly small stream bank protection of Goesan, central Korea. Idong Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods which was nature-friendly stream bank protection. The project aim to maintain or increase stream bank stabilization ecosystem goods and services while protecting downstream and stream bank ecosystem. A number of protecting methods which were a Flight of fieldstone, Vegetation block, Green river block, Stone net, Green environment block, Eco friendly cobble, Vegetation mat and Geo-green cell and Firefly block were applied on the bank of Idong stream. The stream sites have been monitored about vegetation conditions each method in 2007. We selected six points to separately investigate in left and right bank. The main purpose of this study was to find out suitable methods and to improve stream restoration techniques for ecosystem. On the stream bank, H environment block method (9.7) was the highest average of vegetation coverage and Firefly block method (3.87) was the lowest average in applied methods.

• Advances in Computational Design
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• 제7권2호
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• pp.153-171
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• 2022

The present study aimed to find a way to create forms that can simultaneously meet several architectural requirements by applying generative design methods specifically focused on cellular automata. In other words, it is tried to find various forms of architecture that all have common features. Because of the useful features of cellular automata, we decided to use it to generate various forms, but make a relation between the discrete nature of cellular automata and the continuous nature of architecture, was the major problem of our project. To achieve this goal, three consecutive stages were designed. In the first stage, independent variables including the location of the building, the height of the building, and the building area were considered as the inputs of the model. In the second stage, after locating the building, the building's main shell was designed as a hidden geometry for the cellular automata and then the cellular automata were determined based on this shell. The main result of this research is establishing a logical relationship between the discrete geometry of the cellular automata and the continuous search space such that it creates various optimized forms. Although we specify the site plan of this project at Iran-Tehran, this research can be generalized to various design sites as well as different projects, allowing the architectsto alter the cell dimensions, cell density, etc., based on their opinion and project needs.

• 기술혁신학회지
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• 제9권3호
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• pp.558-577
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• 2006

그동안 우리나라는 지속적으로 R&D 투자를 확대하는 등 과학기술 혁신역량을 강화하기 위해 부단히 노력해 왔다. 이러한 결과로 우리나라의 연구개발능력이 크게 신장되었으며, 과학기술지표 측면에서의 수준도 크게 향상된 것으로 나타났다. 또한, 세계 정상급 과학저널로 인정받고 있는 Nature지(誌), Science지(誌), Cell지(誌)(이하, 'NSC')에 우리나라 과학자들이 논문을 게재한 실적 또한 괄목할만하게 증가하였다. 본 연구는 NSC지(誌)에 논문을 게재한 한국인 과학자의 현황을 분석하여 우리나라의 연구역량을 진단하고 연구의 질적 수준 제고를 위한 정책적 시사점을 도출하였다. 특히, 국가연구개발사업 중에서 어떠한 연구개발 프로그램이 NSC 논문을 증가시킨 요인으로 작용하였는지를 구체적 사례를 통해서 분석함으로써 향후 국가연구개발 프로그램의 전략적 추진방안을 모색하였다.

• 센서학회지
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• 제21권3호
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• pp.186-191
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• 2012

In this paper, we present a pH measurement method that uses a microcantilever-array-based biosensor system. It is composed of microcantilever array, liquid cell, micro syringe pump, laser diode array, position sensitive detector, data acquisition device, and data processing software. Four microcantilevers are functionalized with pH-sensitive MHA(mercaptohexadecanoic acid) as a probe, while three microcantilevers are functionalized with HDT(hexadecane thiol) as reference. We prepare PBS(phosphate buffered saline) solutions of different pH and inject them into the liquid cell with a predefined volumetric speed at regular time intervals. The functionalized mircocantilevers in the liquid cell deflect as a self-assembled monolayer on the microcantilever binds with probe molecules in the solution. The difference in deflection between the MHA-covered probe microcantilever and the HDT-covered reference microcantilever was used to compensate for thermal drift. The deflection difference clearly increases with increasing pH in the solution. It was shown that when the pH values of the PBS solutions are high, there were large variations in the deflection of microcantilevers, whereas there were small variations for low pH value. The experimental results show that the microcantilever array functionalized with MHA and HDT can detect pH value with good repeatability.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.453-457
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• 2021

Lithium-sulfur (Li-S) batteries are one of attractive energy conversion and storage system based on high theoretical specific capacity and energy density with low costs. However, volatile nature of elemental sulfur is one of critical problem for their practical acceptance in industry because it considerably affects electrode uniformity during electrode manufacturing. In this work, polymeric sulfur composite consisting of ionic liquid (IL) are suggested to reduce volatility nature of elemental sulfur, resulting in better processibility of the Li-S cell. According to systematic spectroscopic analysis, it is found that polymeric sulfur is consisting of repeating units combining with elemental sulfur and volatility of them is negligible even at high temperature. In addition, the IL-embedded polymeric sulfur shows moderate cycle performance compared to the cell with elemental sulfur. From these results, it is found that the IL-embedded polymeric sulfur composite is applicable cathode candidate for the Li-S cell based on their excellent non-volatility as well as their superior electrochemical performance.