• Journal of Applied Biological Chemistry
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• 제61권4호
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• pp.327-334
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• 2018

Monascus is a source of food colorant with high productivity of the pigment azaphilone. Monascus azaphilone (MAz) is biosynthesized through a single non-reducing polyketide pathway, the major components of which are ankaflavin (1), monascin (2), rubropunctatin (3) and monascorubrin (4); valuable biological activities have been reported for these compounds. Thus, various culture conditions were explored to reduce the cost of culture ingredients, enhance productivity and modulate compound composition. In the present study, we examined an extractive fermentation (EF) method with Diaion HP-20 resin (HP20) in direct comparison to a previously explored method involving Triton X-100 (TX100) to explore the modulated production of the major MAzs. We employed wild-type Monascus purpureus as well as two derivative recombinant strains (${\Delta}mppG$ and ${\Delta}mppE$) that are known to have differential MAz profiles as that of the wild-type strain. The HP20 resin was capable of modulating the MAz profile in favor of orange MAzs 3 and 4, oxidized congeners in this class, as was TX100-a phenomenon not previously observed for TX100 EF with Monascus anka. These finding substantiate that HP20 can be employed for the selective production of oxidized MAz and for diversifying the culture conditions used for Az production.

• Mass Spectrometry Letters
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• 제9권4호
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• pp.91-94
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• 2018

Bilin tetrapyrroles are metabolic products of the breakdown of porphyrins within a species. In the case of mammals, these bilins are formed by the catabolism of heme and can be utilized as either biomarkers in disease or as an indicator of human waste contamination. Although a small subset of bilin tandem mass spectrometry reports exist, limited data is available in online databases for their fragmentation. The use of fragmentation data is important for metabolomics analyses to determine the identity of compounds detected within a sample. Therefore, in this study, the fragmentation of bilins generated by positive ion mode electrospray ionization is examined by collision-induced dissociation (CID) as a function of collision energy on an FT-ICR MS. The use of the FT-ICR MS allows for high mass accuracy measurements, and thus the formulas of resultant product ions can be ascertained. Based on our observations, fragmentation behavior for hemin, biliverdin and its dimethyl ester, phycocyanobilin, bilirubin, bilirubin conjugate, mesobilirubin, urobilin, and stercobilin are discussed in the context of the molecular structure and collision energy. This report provides insight into the identification of structures within this class of molecules for untargeted analyses.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.366-371
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• 2022

Recently many efforts have been made to develop a novel class of non-fullerene electron acceptor materials for high-performance organic solar cells. In this work, anthraquinone derivatives, TMAQ and THAQ, were prepared and their availability as electron acceptor materials for organic solar cells were investigated in terms of optical, thermal, electrochemical properties, and solar cell devices. Compared to TMAQ, a significant bathochromic shift of absorption band was observed for THAQ owing to intramolecular hydrogen-bond-assisted CT interactions. Thanks to the fused aromatic ring structure and benzoquinone unit, both TMAQ and THAQ exhibited a high thermal stability and an efficient electron reduction process. In particular, the intramolecular O-H---O=C hydrogen bond of THAQ plays an important role in improving the thermal stability and electron reduction properties. In the P3HT:acceptor solar cell system, THAQ-based devices had more than ca. 6 times higher power conversion efficiency than TMAQ -based devices. These results serve as a guide for developing high-efficient anthraquinone-based electron acceptor materials.

• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.359-365
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• 2022

The development of efficient electron donor (or hole-transporting) molecules that can be used in various optoelectronic device fields is highly demanded. In this work, a novel class of triptycene-based three-dimensional (3D) triphenylamine (TI-TPA) derivatives with different end substituents was designed and prepared for transparent electron donor materials. Owing to the rigid 3D triptycene framework, the obtained TI-TPA derivatives had an amorphous morphology with high thermal decomposition temperature. The oxidation potential of these TI-TPA derivatives decreased as the electron donating strength of the end substituent increased. Among TI-TPA derivatives, TI-TPA-OMe exhibited the highest HOMO level (-5.31 eV) which is similar to that of Spiro-OMeTAD (-5.22 eV). In addition, TI-TPA-OMe was found to form a strong charge transfer complex with the triptycene-based acceptor TI-BQ, leading to a new absorption band at around 640 nm. These results can be applied for developing efficient electron donor materials that can mimic the advantages of the spiro-linked structure and TPA units of Spiro-OMeTAD.

• 정보교육학회논문지
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• 제12권4호
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• pp.375-384
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• 2008

프로그래밍 교육이 고차원적 사고능력을 함양시켜주는 교육임에도 불구하고, 기존의 프로그래밍 교육은 기본 문법과 구조를 이해하고 프로그램 사용법을 익히는데 너무 많은 노력을 요구하여 학습자들로 하여금 프로그래밍 학습을 기피하거나 포기하도록 만들었다. 이러한 문제점을 극복하기위해 본 연구에서는 배우기 쉽고, 직관적인 교육용 프로그래밍 언어(EPL) '스크래치'를 이용하여 중학생을 대상으로 게임제작 프로그래밍 수업을 12주에 걸쳐 실시하였다. 이와 더불어 교수방법에 있어서 메타인지 사고를 활성화하기위해 '자기질문' 방식을 가미한 시범-실습 수업모형을 활용하였다. 연구결과 스크래치를 이용한 게임제작 프로그래밍 수업은 메타인지에 있어 남녀 모두에게 긍정적 효과가 있음을 확인하였다. 하지만, 자기효능감에 있어서는 여학생 집단에 긍정적 영향을 주지 못했다.

• 문화기술의 융합
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• 제7권4호
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• pp.527-535
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• 2021

창의·융합적 사고력과 문제해결력을 함양시키기 위해, 창의·융합교육을 과학고 학생들에게 처치하였으며, 수업처치 후 학생과 교사들의 인식변화를 조사하였다. 학생들의 인식조사 결과, 창의적 문제해결력 신장, 교육 만족도, 등 융합수업에 대한 학생들의 인식이 매우 긍정적으로 나타났으며, 98% 이상의 학생들이 앞으로도 융합교육 수업에 계속해서 참여하겠다고 응답하였다. 한편, 수업활동 시간 부족으로 문제해결 미완성이 학생들에게 부담으로 작용하였으며, 한 학기당 20~30% 이내에서 이 프로그램이 운용되길 바라고 있었다. 특히 융합교육의 효과를 높이기 위해, 나노과학의 내용 및 교수-학습 활동을 과학고 학생들의 인지발달 수준을 고려하여 알맞게 구성하였다. 또한, 학생들에 대한 교사들의 인식 조사 결과, '자기주도적 학습능력', '문제해결 능력', 등에서 80.0% 이상의 교사들이 매우 긍정적으로 응답하였다.

• 천문학회보
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• 제46권2호
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• pp.37.3-38
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• 2021

One of the key questions on star formation is how the organic molecules are synthesized and delivered to the planets and comets since they are the building blocks of prebiotic molecules such as amino acid, which is thought to contribute to bringing life on Earth. Recent astrochemical models and experiments have explained that complex organic molecules (COMs; molecules composed of six or more atoms) are produced on the dust grain mantles in cold and dense gas in prestellar cores. However, the chemical networks and the roles of physical conditions on chemistry are not still understood well. To address this question, hot (> 100 K) cores in high mass young stellar objects (M > 8 Msun) are great laboratories due to their strong emissions and larger samples than those of low-mass counterparts. In addition, CH₃OH masers, which have been mostly found in high mass star forming regions, can provide constraints due to their very unique emerging mechanisms. We investigate twelve high mass star forming regions in ALMA band 6 observation. They are associated with 44/95 GHz Class I and 6.7 GHz Class II CH3OH masers, implying that the active accretion processes are ongoing. For these previously unresolved regions, 66 continuum peaks are detected. Among them, we found 28 cores emitting COMs and specified 10 cores associated with 6.7 GHz Class II CH3OH masers. The chemical diversity of COMs is found in cores in terms of richness and complexity; we identified up to 19 COMs including oxygen- and nitrogen-bearing molecules and their isotopologues in a core. Oxygen-bearing molecules appear to be abundant and more complex than nitrogen-bearing species. On the other hand, the COMs detection rate steeply grows with the gas column density, which can be attributed to the effective COMs formation in dense cores.

• 한국환경과학회지
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• 제13권3호
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• pp.301-311
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• 2004

The purpose of this study was to examine teachers’ awareness of chemical waste produced in elementary school laboratory experimentation and how this awareness relates to collection and disposal of chemical waste. More specifically, the study looked at the correlation between the handling of chemical waste and factors such as years of teachers’ educational career, class size and amount of waste produced. The target population were 250 elementary school teachers in Gyeongnam area and 237 subjects were responded. Among the 237 responses, 37 cases that did not complete the questionnaire were eliminated. Therefore, 200 responses were analyzed in this study. The survey questionnaire consisted of 15 questions. The categories of the questionnaire were their skills of management and treatment of the chemical waste. The data collected were analyzed by SPSS 10.0, and the relations among variables such as class sizes and years of teaching experience were also analyzed by $x^2-test.$ The results in this study were as follows: First, there were no significant differences between the years of teaching and class sizes in the training experience of chemical waste disposal. Second, there was a significant difference between the science laboratory size and class sizes in the laboratory actual condition. In addition, in the relations between the number of times of experimentation and the years of teaching experience, there was a significant difference. Third, in terms of the discharge amount of chemical waste, there was a significant difference between the years of teaching and class sizes. Fourth, in the simple chemistry waste disposal process in the science laboratory, there also was a significant difference between the kinds of experimental equipments that used in the experimentation and the years of teaching. Based on this study, it was found that great amount of the chemical wastes produced in the science laboratory dumped into the drain and the treatment process of chemical waste was also inattentive. Even the importance of environmental education is emphasized in the elementary education, the basic problems occurred in the science laboratory is disregarded. Therefore, not only students but teachers have to pay attention to the disposal process of chemical waste in the laboratory in order to prevent environment pollution. Furthermore, the efforts of preventing environment pollution are needed such as opening the teacher training course about environment education, minimal use of chemicals, treatment of chemical waste, and so forth.

• 공업화학
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• 제21권2호
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• pp.142-147
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• 2010

1%, 2%, 10% 및 18%의 가교도를 가진 스타이렌(제4류 위험물 중 제2석유류) 디비닐벤젠 공중합체에 1-aza-18-crown-6 거대 고리 리간드를 치환반응으로 결합시켜 수지들을 합성하였으며, 이들 수지의 합성은 염소 함량과 원소 분석, 비표면적(BET), 그리고 IR-분광법으로 확인하였다. 물 소화약제로부터 합성수지 흡착제에 대한 금속 이온의 흡착에 미치는 pH, 시간 그리고 수지의 가교도에 따른 영향들을 조사한 결과 금속 이온들은 pH 3 이상에서 큰 흡착율을 보였으며, 금속 이온들의 흡착 평형은 2 h 정도였고, 수용액에서 수지에 대한 흡착 선택성은 나트륨($Na^{1+}$) > 아연($Zn^{2+}$) > 크롬($Cr^{3+}$) 이온의 순서이며, 금속 이온의 흡착력은 1%, 2%, 10% 및 18%의 가교도 순이었다.

• 대한화학회지
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• 제46권1호
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• pp.76-82
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• 2002

본 연구에서는 과학 개념 학습을 위한 소집단 토론에서 지식구성 과정에서의 언어적 상호작용을 촉진하기 위한 방안으로 인지적 역할 부여의 효과를 조사하였다. 중학교 1학년 학생 62명을 대상으로 설명, 반박, 정리, 조정 활동을 촉진하는 인지적 역할을 부여한 소집단 토론 수업(CR)과 특정한 역할을 부여하지 않은 소집단 토론 수업(NSR)을 9차시 동안 실시하였다. 수업 처치 후, 학업 성취도, 개념 이해도, 과학 학습 환경에 대한 인식, 토론에 대한 인식 검사를 실시하였다. 이원 공변량 분석 결과, 학업 성취도 점수에서 사전 성취 수준 하위 학생들의 경우 NSR 집단이 CR 집단보다 점수가 유의미하게 높았다. 개념 검사에서도 유사한 경향성이 나타났다. 과학 학습 환경 인식과 토론에 대한 인식 검사 점수에서는 집단 간에 유의미한 차이가 없었다.