Fish biochemical effect monitoring of chemical stressors in Korean costal area

Youmi Choi,Dongju Shin,Sang Hee Hong,Gi Myung Han,Seungbae Choi,Changwan Kang,Jee-Hyun Jung (사)한국해양생명과학회 2020 (사)한국해양생명과학회 학술대회 Vol.2020 No.06

Catechin-capped gold nanoparticles: green synthesis, characterization, and catalytic activity toward 4-nitrophenol reduction

Choi, Yoonho,Choi, Myung-Jin,Cha, Song-Hyun,Kim, Yeong Shik,Cho, Seonho,Park, Youmie Springer 2014 NANOSCALE RESEARCH LETTERS Vol.9 No.1

<P>An eco-friendly approach is described for the green synthesis of gold nanoparticles using catechin as a reducing and capping agent. The reaction occurred at room temperature within 1 h without the use of any external energy and an excellent yield (99%) was obtained, as determined by inductively coupled plasma mass spectrometry. Various shapes of gold nanoparticles with an estimated diameter of 16.6 nm were green-synthesized. Notably, the capping of freshly synthesized gold nanoparticles by catechin was clearly visualized with the aid of microscopic techniques, including high-resolution transmission electron microscopy, atomic force microscopy, and field emission scanning electron microscopy. Strong peaks in the X-ray diffraction pattern of the as-prepared gold nanoparticles confirmed their crystalline nature. The catalytic activity of the as-prepared gold nanoparticles was observed in the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH<SUB>4</SUB>. The results suggest that the newly prepared gold nanoparticles have potential uses in catalysis.</P>

Developmental Toxic Effects of Hull Cleaning Wastewater on embryonic fish

Youmi Choi,Dongju Shin,Moonkoo Kim,Jung-Hoon Kang,Min-Chul Jang,Jee-Hyun Jung (사)한국해양생명과학회 2020 (사)한국해양생명과학회 학술대회 Vol.2020 No.06

Effects of the coastal sediment extracts containing persistent organic pollutants (POPs) on embryonic flounder

Youmi Choi,Moonkoo Kim,YoungMi Lee,Jee-Hyun Jung (사)한국해양생명과학회 2019 (사)한국해양생명과학회 학술대회 Vol.2019 No.10

Toxic Effects of Polyethylene Terephthalate Particulate Uptake Exposure to Black Rockfish Sebastes schlegelii

Kwang-Min Choi,Seong Hee Mun,Dongju Shin,Youmi Choi,Jee-Hyun Jung (사)한국해양생명과학회 2023 (사)한국해양생명과학회 학술대회 Vol.2023 No.06

Platycodon saponins from Platycodi Radix ( <i>Platycodon grandiflorum</i> ) for the Green Synthesis of Gold and Silver Nanoparticles

Choi, Yoonho,Kang, Sehyeon,Cha, Song-Hyun,Kim, Hyun-Seok,Song, Kwangho,Lee, You Jeong,Kim, Kyeongsoon,Kim, Yeong Shik,Cho, Seonho,Park, Youmie Springer US 2018 NANOSCALE RESEARCH LETTERS Vol.13 No.1

<P>A green synthesis of gold and silver nanoparticles is described in the present report using platycodon saponins from Platycodi Radix (<I>Platycodon grandiflorum</I>) as reducing agents. Platycodin D (PD), a major triterpenoidal platycodon saponin, was enriched by an enzymatic transformation of an aqueous extract of Platycodi Radix. This PD-enriched fraction was utilized for processing reduction reactions of gold and silver salts to synthesize gold nanoparticles (PD-AuNPs) and silver nanoparticles (PD-AgNPs), respectively. No other chemicals were introduced during the reduction reactions, providing an entirely green, eco-friendly, and sustainable method. UV-visible spectra showed the surface plasmon resonance bands of PD-AuNPs at 536 nm and PD-AgNPs at 427 nm. Spherically shaped nanoparticles were observed from high-resolution transmission electron microscopy with average diameters of 14.94 ± 2.14 nm for PD-AuNPs and 18.40 ± 3.20 nm for PD-AgNPs. Minor triangular and other polygonal shapes were also observed for PD-AuNPs along with spherical ones. Atomic force microscopy (AFM) images also demonstrated that both nanoparticles were mostly spherical in shape. Curvature-dependent evolution was employed to enhance the AFM images and precisely measure the sizes of the nanoparticles. The sizes were measured as 19.14 nm for PD-AuNPs and 29.93 nm for PD-AgNPs from the enhanced AFM images. Face-centered cubic structures for both nanoparticles were confirmed by strong diffraction patterns from high-resolution X-ray diffraction analyses. Fourier transform infrared spectra revealed the contribution of –OH, aromatic C=C, C–O, and C–H functional groups to the synthesis. Furthermore, the catalytic activity of PD-AuNPs was assessed with a reduction reaction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. The catalytic activity results suggest the potential application of these gold nanoparticles as catalysts in the future. The green strategy reported in this study using saponins as reducing agents will pave new roads to develop novel nanomaterials with versatile applications.</P>

국내 대학 외국인 유학생 대상 체험형 한국 문화 비교과 프로그램 운영 원리 연구

최유미, 박석준 배재대학교 주시경교양교육연구소 2024 대학교양교육연구 Vol.9 No.1

본 연구는 국내 대학의 외국인 유학생 대상 비교과 활동의 일환으로 체험형 한국 문화프로그램의 개념과 운영 원리를 제시하는 데에 목적이 있다. 국내에 유입되는 학문 목적 한국어 학습자의 증가와 국내 학력 인구의 감소로 인해 국내 대학에서의 외국인 유학생 비율이 증가하고 있으며, 이에 따라 외국인 유학생의 적응과 학업 성취에 대한 관심도 높아지고 있다. 이에 외국인 유학생들이 한국 문화를 깊이 이해하고 글로벌 시민으로서의 역량을 향상시키기 위한 체험형 한국 문화 비교과 프로그램의 운영 원리를 제시하고자 하였다. 연구 방법으로는 문헌 고찰과 조사를 통한 체험형 한국 문화 비교과 프로그램의 핵심 원리 분석을 사용하였다. 연구 결과, 학습자 중심의 접근, 다양한 문화적 체험의 제공, 그리고 지속적인 개선과 변화에 대한 적응이 프로그램 운영의 핵심 요소로 확인되었다. 이러한 원리들은 외국인 유학생들이 한국 문화를 더 깊이 이해하고 학습 목표를 달성하는 데 중요한 역할을 한다. 본 연구는 학문 목적의 학습자를 위한 체험형 문화 교육 프로그램을 개발하고 운영하는 데 있어 기초적인 지침을 제공한다. The purpose of this study is to define the concept and operational principles of an experience-based Korean culture program designed for international students, as part of non curricular activities. Due to the increasing influx of students coming to Korea for academic purposes and a simultaneous decline in the domestic student popopulation, the proportion of international students in Korean universities has seen a significant rise. This has led to an increased focus on the adaptation and academic success of international students. In response, this study aims to outline the operational principles of an experiential Korean culture non-curricular program that aims to deepen international students’ understanding of Korean culture and enhance their competencies as global citizens. The methodology employed involved analyzing the core principles of experiential Korean culture non-curricular programs through literature reviews and surveys. The findings highlight that a learner-centered approach, providing a variety of cultural experiences, and adapting to ongoing improvements and changes are critical to the operation of the program. These principles are crucial in aiding international students in gaining a deeper understanding of Korean culture and achieving their learning goals. This research offers fundamental guidelines for the development and management of experience-based cultural education programs targeted at academic learners.

도서지역 고령자의 주거 공간 실태 분석

최유나(Choi, Youna),이유미(Lee, Youmi),이윤재(Lee, Younjae) 한국디자인지식학회 2014 디자인지식저널 Vol.32 No.-

본 연구의 목적은 도서지역 고령자 주거의 문제점과 특수성을 조사 분석하고 주거환경 개선을 위한 방향을 제안하는 데 있다. 연구방법으로 전라남도 완도군 서넙도 지역에 거주하는 60세 이상의 고령 거주자가 포함된 10가구를 편의표집 하여 실태조사를 실시하였다. 연구결과는 다음과 같다. 첫째, 고령자의 주택은 전통홑집형, 전통개조형, 현대 거실중심형으로 분류되고 전통형에서 현대형으로 변하는 과도기적 단계로 분석된다. 둘째, 주택 진입부의 경사와 계단 그리고 단차가 큰 툇마루는 고령자의 낙상사고 위험을 높이는 장애요소로서 개선이 필요하였고 현관과 현관수납장이 설치되지 않은 가구가 많아, 부적절한 장소에 신발 및 물품보관하고 있으며 이러한 행태는 고령자에게 매우 불편하고 부적절한 동작을 유도하였다. 셋째, 부엌 내 작업대 높이가 고령자의 인체에 맞지 않아 불편을 느끼고 있었으며 화재경보기와 가스감지기와 같은 안전장치가 설치되지 않았다. 넷째, 재래식 화장실로 인해 신체적 불편함이 야기되고 주택 내부에서 외부로 이어지는 긴 동선으로 화장실에 대한 접근성이 낮았다. 다섯째, 서넙도 지역의 특수공간으로서 제사를 지내기 위한 마루방이 있으며 마루방의 기능이 주택에 포함될 것에 대한 요구가 많았다. The purpose of this study is to investigate characteristics and problems of elderly housing(households including elderly people) in islands area and to propose improvements of housing environment. As a research method, 10 households including elderly people aged 60 and more were selected in Seoneopdo by the convenient sampling. The results are as follows. Firstly, the elderly housing is classified into a traditional single-wing housing, a renovated traditional housing and a living room centered modern housing. Secondly, the slopes, stairs and "toenmarus" with high thresholds at the entrance are obstacles increasing the risk of falling accidents and many households did not installed foyer and shoe cabinets. Thirdly, the elderly feel inconvenient in the kitchen, because the height of worktable is unfit to their tall, and fire and gas detectors were not installed. Fourthly, using the old-style toilets causes physical discomfort. In addition, the long circulation between inside and outside decreases the level of approachment to the toilet. Fifthly, there is named ‘marubang’ as a special space for ancestral rites.Elderly people need the room for the function of ‘marubang’

Artemisia capillaris extracts as a green factory for the synthesis of silver nanoparticles with antibacterial activities.

Park, Youmie,Noh, Hwa Jung,Han, Lina,Kim, Hyun-Seok,Kim, Yong-Jae,Choi, Jae Sue,Kim, Chong-Kook,Kim, Yeong Shik,Cho, Seonho American Scientific Publishers 2012 Journal of Nanoscience and Nanotechnology Vol.12 No.9

<P>We report a green synthesis of silver nanoparticles that uses extracts from the aerial part of Artemisia capillaris. Both water and 70% ethanol extracts successfully generated silver nanoparticles. The formation of silver nanoparticles was confirmed by surface plasmon resonance bands, Fourier transform-infrared spectra, high resolution-transmission electron and atomic force microscopic images. Various shapes of silver nanoparticles were generated with an average diameter of 29.71 nm with water extract and 29.62 nm with 70% ethanol extract. An improvement in antibacterial activity (MIC 8.35-16.7 microg/mL) was observed against a total of twenty different strains of Gram-negative and Gram-positive bacteria. A remarkable enhancement (approximately 12-fold) was observed against Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, Klebsiella oxytoca, and Klebsiella areogenes when compared with the extract alone. Silver nanoparticles produced by the 70% ethanol extract showed slightly higher antibacterial activity than those generated with the water extract. The correlation between total flavonoid content of each extract and the antibacterial activity did not exert any significant relationships. This report suggests that plant extracts have the potential to be used as powerful reducing agents for the production of biocompatible silver nanoparticles possessing enhanced antibacterial activities.</P>

드레비단 : 한국전통문화예술의 재해석을 통한 프리미엄 컬쳐 브랜드 제안

최서영(Choi Seoyoung),서유미(Suh Youmi),정혜욱(Hyeuk Chung) 한국디자인학회 2023 한국디자인학회 학술발표대회 논문집 Vol.2023 No.10