• Toxicological Research
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• 제20권3호
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• pp.205-211
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• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Elastomers and Composites
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• 제44권3호
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• pp.196-208
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• 2009

감응 성질을 탑재한 복잡한 고분자 재료가 시장에 등장하기 시작하고 있다. 가역적이며 비공유성인 상호작용을 사용하여 이와 같은 감응형 재료를 설계하는 예가 많아지고 있다. 최근에 개발된 수소결합 단위가 이와 같은 설계 기법을 극으로 치닫게 하고 있다. 단량체를 이어주는 힘이 수소결합뿐인 초분자 고분자는 온도나 용매의 변화에 기계적 성질이 감응되는 재료를 형성한다. 본 보문에서는 수소결합으로 이루어진 초분자 고분자가 자기치유 재료로 사용되는 예를 소개한다. 재생 가능한 고무성 재료를 합성하는 일은 그리 매력적이라 할 수 없다. 그러나 상온에서 접착제를 사용하지 않고도 손상을 반복해서 치유할 수 있는 고무 재료는 우리의 상상의 나래를 펼치게 하는 재료이다. 외부의 간섭 없이 환경적 자극에 비선형적으로 감응하여 파손된 부분을 치유시키는 재료인 자기치유 재료는 여러 가지 첨단공학 계에서 엄청난 가능성을 가진 재료라 할 수 있다.

• 한국과학교육학회지
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• 제30권6호
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• pp.799-814
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• 2010

본 연구의 목적은 화석 전시에 관한 깊이 있는 이해와 추론적인 사고를 유도하는 질문으로 구성된 도구를 개발하고 이를 활용한 관람과 그렇지 않은 자유관람 사이의 소통의 특징을 행위 단위 및 대화 유형으로 비교하는 것이다. 몇 단계의 개발과정을 거쳐, 최종적으로 포괄적이면서 추론적 흐름을 가진 아홉 개의 질문으로 구성된 질문카드세트를 개발하였다. 질문카드의 활용에 따른 소통의 특징을 알아보기 위해, 국립과천과학관 자연사전시관에서 자료를 수집하였다. 연구참여자는 또래 관람객 총 열 여덟(18) 그룹(초등학교 5학년에서 중학교 3학년까지)이며, 이들의 관람을 비디오로 녹화하고 전사하여 분석하였다. 전반적인 관람 행태로서 관람 소요 시간(holding time)과 관람 행위(action)를 측정하였는데, 이 중 관람 행위는 크게 '보기(look)', '말하기(speech)', '행동하기 (motion)'로 나누고, 각각 세부적인 요소들로 더 자세히 구분하여 발생빈도를 분석하였다. 또한 말하기 관련 세부 요소들을 바탕으로 하여 대화 유형(type of conversation)을 구분하여 분석하는데, 크게 '열거 (enumerative),' '합의(consensual),' '응답 (responsive),' '논의(argumentative)'로 나누고, 각각의 빈도를 분석하였다. 분석 결과. 질문카드를 활용하는 관람에서는 자유관람보다, 전시물 별 관람 소요 시간 및 대부분의 관람 행위들이 유의미하게 증가하였다. 또한 전반적인 대화의 빈도도 증가하였는데, 특히 '응답'을 제외한 나머지 대화의 유형은 모두 유의미하게 증가하였다. 결론적으로, 질문카드는 전시 물-관람객 간 또는 관람객-관람객 간 소통을 활발히하고, 관람객의 추론적 사고 활동을 촉진하며, 관람객에게 무엇을 어떻게 보아야 하는지에 대해 안내함으로써 보다 집중력 있고 의미 있는 관람이 가능하도록하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.10.2-10.2
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• 2011

The design and synthesis of protein-like polymers is a fundamental challenge in materials science. A biomimetic approach is to explore the impact of monomer sequence on non-natural polymer structure and function. We present the aqueous self-assembly of two peptoid polymers into extremely thin two-dimensional (2D) crystalline sheets directed by periodic amphiphilicity, electrostatic recognition and aromatic interactions. Peptoids are sequence-specific, oligo-N-substituted glycine polymers designed to mimic the structure and functionality of proteins. Mixing a 1:1 ratio of two oppositely charged peptoid 36 mers of a specific sequence in aqueous solution results in the formation of giant, free-floating sheets with only 2.7 nm thickness. Direct visualization of aligned individual peptoid chains in the sheet structure was achieved using aberration-corrected transmission electron microscopy. Specific binding of a protein to ligand-functionalized sheets was also demonstrated. The synthetic flexibility and biocompatibility of peptoids provide a flexible and robust platform for integrating functionality into defined 2D nanostructures. In the later part of my talk, we describe the use of metal ions to construct two-dimensional hybrid films that have the ability to self-heal. Incubation of biomimetic peptoid polymers with specific divalent metal ions results in the spontaneous formation of uniform multilayers at the air-water interface. We anticipate that ease of synthesis and transfer of these two-dimensional materials may have many potential applications in catalysis, gas storage and sensing, optics, nanomaterial synthesis, and environmentally responsive scaffolds.

• Journal of Plant Biotechnology
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• 제36권1호
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• pp.45-52
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• 2009

In order to understand the molecular interactions that occur between rice and the rice blast fungus during infection, we previously identified a number of rice blast fungal elicitor-responsive genes from rice (Oryza sativa cv. Milyang 117). Here, we report the cloning and characterization of the rice fungal elicitor-inducible gene Oshin1 (GenBank Accession Number AF039532). Sequence analysis revealed that the Oshin1 cDNA is 1067 bp long and contains an open reading frame encoding 205 amino acid residues. The Oshin1 gene shows considerable sequence similarity to the tobacco hin1 and hin2 genes. The predicted Oshin1 protein has a cysteine-rich domain at the N-terminus and is rich in leucine, serine, and alanine residues. Southern blot analysis suggests that Oshin1 gene is a member of a small gene family in the rice genome. To examine the expression of Oshin1, Northern blot analysis was conducted. Expression of the Oshin1 transcript is rapidly induced in suspension-cultured rice cells treated with fungal elicitor, salicylic acid or hydrogen peroxide. In addition, Oshin1 transcript levels are rapidly increased by treatment with $Ca^{2+}$/A23187. The expression of Oshin1 was also elevated in 3-week old leaf tissues upon ethephon application or fungal elicitor treatment. Our results suggest that the Oshin1 gene is involved in plant defense responses to environmental stresses.

• Journal of Information Science Theory and Practice
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• 제5권4호
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• pp.68-80
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• 2017

The invention of computers is one of the best things that have ever happened to mankind and undergraduate students can benefit immensely from the use of computers. However, observations have showed that in the present Nigerian society, there are a number of issues arising from unethical use of computers. Interactions with some undergraduate students revealed that a majority have fallen into the trap of unethical use of computers at one time or another. This seemingly alarming rate of unethical use of computers therefore calls for concern. A literature search has shown that awareness and perception of computer ethics have not been adequately researched within the Nigerian context. Thus, the main objective of this study was to examine the awareness and perception of computer ethics by undergraduate students in a Nigerian university. Descriptive survey research method was used and the study population was comprised of 12,894 undergraduate students of the University of Ibadan, Nigeria. The multistage random sampling technique was used to select a sample size of 292 and the questionnaire was used to collect data. Findings showed that the level of awareness of respondents on issues associated with computer ethics was high (mean=45.19). A majority of the respondents had a favorable perception of computer ethics and the most prominent factor identified that could hinder adherence to computer ethics as noted by most of the respondents was the poor economic situation of the country. Part of the recommendations was that government at all levels should provide responsible and responsive leadership.

• Child Studies in Asia-Pacific Contexts
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• 제3권2호
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• pp.139-158
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• 2013

The present study investigated the direct and interactive effects of children's temperament and mothers' reactions to hypothetical vignettes of children's aggression on 3- to 6-year-old children's overt aggression (OA) and relational aggression (RA). A total of 317 mothers of 3- to 6-year-old children and 26 teachers from eight day-care centers and kindergartens were contacted. Each mother reported her child's background, assessed her child's temperament and responded to the Mothers' Reaction to Hypothetical Vignettes of Children's Aggression (MRCA) scale. Children's OA and RA were assessed by teachers. Results showed that high levels of children's surgency predicted children's OA and RA. Although mothers' reactions did not predict children's OA and RA directly, significant interactions indicated that mothers' restrictive reactions were more strongly related to children's OA for children with high levels of surgency and low levels of effortful control. In addition, mothers' responsive reactions were more strongly related to children's OA for children with low levels of surgency. This study demonstrates that relative contributions of children's temperament and mothers' reactions differ according to the form of children's aggression. It also shows that certain types and levels of mothers' reactions to children's aggressive behavior can be critical for children with certain types and levels of temperament in developing children's overt aggression. The findings of this study can be applied to building early prevention and future intervention programs for young children's aggression.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.196-204
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• 2011

Abiotic stress is the primary cause of crop loss worldwide, reducing average yields for most major crop plants by more than 50%. In addition, future agricultural production and management will encounter multifaceted challenges from global climate change. Therefore, it is necessary to study the molecular response of crop plants to the stresses in order to develop appropriate strategies to sustain food production under adverse environmental conditions. We carried out a large scale proteomic analysis of soybean plants in response to various abiotic stresses, including drought, salinity, waterlogging and their interactions. Proteins were analyzed by two dimensional polyacrylamide gel electrophoresis followed by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. The identified proteins are involved in a wide range of cellular functions. In addition to the well known stress-associated proteins, we identified several novel proteins, which were not reported before. In many cases our proteomic data bridges the gap between mRNA and metabolite data. Our studie provides new insights into identification of abiotic stress responsive proteins in soybean, and demonstrates the advantages of proteomic analysis in dissecting metabolic and regulatory networks.

• Molecules and Cells
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• 제40권5호
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• pp.315-321
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• 2017

The inositol polyphosphates are a group of multifunctional signaling metabolites whose synthesis is catalyzed by a family of inositol kinases that are evolutionarily conserved from yeast to humans. Inositol polyphosphate multikinase (IPMK) was first identified as a subunit of the arginine-responsive transcription complex in budding yeast. In addition to its role in the production of inositol tetrakis- and pentakisphosphates ($IP_4$ and $IP_5$), IPMK also exhibits phosphatidylinositol 3-kinase (PI3-kinase) activity. Through its PI3-kinase activity, IPMK activates Akt/PKB and its downstream signaling pathways. IPMK also regulates several protein targets non-catalytically via protein-protein interactions. These non-catalytic targets include cytosolic signaling factors and transcription factors in the nucleus. In this review, we highlight the many known functions of mammalian IPMK in controlling cellular signaling networks and discuss future challenges related to clarifying the unknown roles IPMK plays in physiology and disease.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1137-1143
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• 2019

Hepatitis E virus (HEV) accounts for 20 million infections in humans worldwide. In most cases, the infections are self-limiting while HEV genotype 1 infection cases may lead to lethal infections in pregnant women (~ 20% fatality). The lack of small animal models has hampered detailed analysis of virus-host interactions and HEV-induced pathology. Here, by employing a recently developed culture-adapted HEV, we demonstrated that methyltransferase, a non-structural protein, strongly inhibits melanoma differentiation-associated gene 5 (MDA5)-mediated activation of type I interferon responses. Compared to uninfected controls, HEV-infected cells display significantly lower levels of $IFN-{\beta}$ promoter activation when assessed by luciferase assay and RT-PCR. HEV genome-wide screening showed that HEV-encoded methyltransferase (MeT) strongly inhibits MDA5-mediated transcriptional activation of $IFN-{\beta}$ and $NF-{\kappa}B$ in a dose-responsive manner whether or not it is expressed in the presence/absence of a tag fused to it. Taken together, current studies clearly demonstrated that HEV MeT is a novel antagonist of MDA5-mediated induction of $IFN-{\beta}$ signaling.