Antiproliferative Effect of Artemisia scoparia against Growth of Human Cancer Cells

Heejeong JEONG,Hojun KIM,Eunshin JU,Youngwan SEO 한국생물공학회 2015 한국생물공학회 학술대회 Vol.2015 No.10

Chemically Robust Superhydrophobic Poly(vinylidene fluoride) Films with Grafting Crosslinkable Fluorinated Silane

Jeong, Heejeong,Baek, Seolhee,Han, Singu,Jang, Hayeong,Rockson, Tonnah Kwesi,Lee, Hwa Sung The Polymer Society of Korea 2018 Macromolecular Research Vol.26 No.6

A superhydrophobic surface with excellent chemical stability was fabricated using the spraying method, one of the most efficient technologies for producing large-area coatings at low cost. Poly(vinylidene fluoride) (PVDF) was used as a hydrophobic polymer material, and heptadecafluoro-1,1,2,2,-tetra-hydrodecyl)trichlorosilane (FTS), which reacts with moisture during curing, was used to improve the water repellency and durability. Spray coating of PVDF alone yielded PVDF nanostructures described by the Cassie-Baxter model. The water contact angle of a water droplet on this surface, however, was <TEX>$128^{\circ}$</TEX>, indicating that the surface was not superhydrophobic. On the other hand, spray-coating a mixed PVDF-FTS solution provided a complex and homogeneous nanostructured surface with excellent water repellency and a contact angle of up to <TEX>$159^{\circ}$</TEX>. Immersion of the PVDF-only film for 20 min in N,N-dimethylformamide (DMF), a good solvent for PVDF, led to complete dissolution of the film. By contrast, the PVDF-FTS film maintained its superhydrophobicity with a water contact angle of <TEX>$151^{\circ}$</TEX> after 20 min of immersion in DMF, and still exhibited a high contact angle of <TEX>$142^{\circ}$</TEX> after 1 h. The PVDF-FTS film developed in the present work should enable the production of large-area superhydrophobic coatings at low cost using a simple spray process. Moreover, the PVDF-FTS film displayed excellent stability against solvents, thus increasing its suitability for robust superhydrophobic applications.

Dense Assembly of Soluble Acene Crystal Ribbons and Its Application to Organic Transistors

Jeong, Heejeong,Han, Singu,Baek, Seolhee,Kim, Se Hyun,Lee, Hwa Sung American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.37

<P>The preparation of uniform large-area highly crystalline organic semiconductor single crystals remains a challenge in the field of organic field-effect transistors (OFETs). Crystal densities in the channel regions of OFETs have not yet reached sufficiently high values to provide efficient charge transport, and improving channel crystal densities remains an important research area. Herein we fabricated densely well-aligned single crystal arrays of the 6,13bis(triisopropylsilylethynyl)pentacene (TIPS_PEN) semiconductor using a straightforward scooping-up (SU) methodology to quickly produce a large-area self-assembled semiconductor crystal layer. The resulting crystalline TIPS_PEN strip arrays obtained using the SU method revealed a packing density that was 2.76 times the value obtained from the dip-coated channel, and the mean interspatial distance between the crystal strips decreased from 21.5 to 7.8 yin: The higher crystal packing density provided efficient charge transport in the FET devices and directly yielded field-effed mobilities as high as 2.16 cm(2)/(V s). These field-effect mobilities were more than three times the values obtained from the OFETs prepared using dip-coated channels. Furthermore, the contact resistance between the source/drain electrodes and the TIPS_PEN crystals decreased by a factor of 2. These contributions represent a significant step forward in improving semiconductor crystal alignment for the fabrication of large-area high-performance organic electronics.</P>

Control of Epitaxy Growth Affording High Electrical Performance of Organic Semiconductors

Heejeong Jeong,Hwasung Lee 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

스마트폰 기반 모바일 전자정부의 발전수준 측정 및 영향요인 분석: 지방자치단체의 스마트폰 모바일 애플리케이션을 중심으로

정희정 ( Heejeong Jeong ),김준형 ( Jun Houng Kim ),엄석진 ( Seok Jin Eom ) 한국행정학회 2016 韓國行政學報 Vol.50 No.2

이 연구의 목적은 한국의 지방자치단체가 제공하는 스마트폰 애플리케이션을 중심으로 스마트폰 기반의 모바 일 전자정부의 발전수준을 측정하고 그에 대한 영향요인을 분석하는 것이다. 2012년과 2015년에 진행된 지방자치단체의 스마트폰 앱 전수조사 자료를 분석하여 도출된 주요 결과는 다음과 같다. 첫째, 스마트폰 기반의 모바일 전자정부가 상당한 수준으로 구현되고 있음이 발견되었다. 지방자치단체가 제공하는 스마트폰 앱이 양적으로 크게 증가하였을 뿐만 아니라, 발전수준 측면에서도 고도화되었다. 둘째, 광역자치단체가 제공하는 스마트폰 앱을 대상으로 스마트폰 앱 발전수준에 대한 영향요인을 분석한 결과, 자치단체장의 정보화 리더 십과 정보화 관련 제도화 수준이 긍정적인 영향을 미치는 반면, 유선 전자정부 성과 및 자치단체의 정보화 역량, 그리고 정보화담당관의 제도적 위상은 부정적인 영향을 미치는 것으로 분석되었다. 이와 같은 결과를 바탕으로 스마트폰 기반 모바일 전자정부에 대한 향후 연구과제와 정책 제언을 제시하였다. This study measures the level of development of smartphone-based mobile government, which centers on the smartphone application and its influential factors. Major research findings from an analysis of the smartphone applications provided by Korean local governments in 2012 and 2015 are as follows. First, smartphone-based mobile government was found to be actualized to a significant degree. Not only did the number of smartphone applications provided by Korean local governments increase sharply, but there was also an increasein their level of development. Second, an analysis of the influential factors for the development level of the smartphone applications provided by metropolitan local governments in Korea showed that local governors`` informatization leadership and informatization-related institutional arrangements had a positive influence, whereas in the era of wired e-government, local governments`` informatization capacity and chief information officers`` institutional position had a negative influence on the development level of the smartphone applications. Based on these research findings, this study illustrates future resear

러닝머신 사용편리성 관점의 사용자 인터페이스(UI) 연구

정희정(Heejeong Jeong),이아현(Ahyun Lee),이윤경(YunGyoung Lee),장윤정(YunJeong Jang),이재인(Jaein Lee) 대한인간공학회 2020 대한인간공학회 학술대회논문집 Vol.2020 No.10

Water Space and Urban Environment

정희정(Jeong Heejeong) 현대건축사 2010 (월간)Maru Vol.- No.101

2022 양자정보과학 여름학교 참가기

정희정(Heejeong JEONG) 한국물리학회 2022 물리학과 첨단기술 Vol.31 No.11

염생식물 가는갯는쟁이 용매 추출물의 항염증활성

정희정(Heejeong Jeong),김호준(Hojun Kim),주은신(Eunsin Ju),이슬기(Seul-Gi Lee),공창숙(Chang-Suk Kong),서영완(Youngwan Seo) 한국생명과학회 2017 생명과학회지 Vol.27 No.2

본 연구에서는 염생식물을 이용한 생리활성 소재 개발 연구의 일환으로 가는갯능쟁이의 용매 추출물 및 분획물을 제조하여 LPS로 염증을 유도한 마우스 유래 macrophages에서의 NO 생성 및 염증관련인자의 발현에 미치는 영향을 검토하여 가는갯능쟁이의 항염증 소재로서의 이용 가능성을 검토하였다. 가는갯능쟁이는 methylene chloride와 methanol을 이용하여 제조한 조추출물(crude extract, 48.3 mg)을 용매극성에 따라 단계적으로 분획하여 n-hexane 층(11.5 mg), 85% aqueous methanol 수용액층(85% aq. MeOH, 11.3 mg), n-butanol 층(n-BuOH, 11.2 mg)과 water 층(12.3 mg)을 얻었다. 가는갯능쟁이의 조추출물 및 분획물의 RAW264.7 대식세포에 대한 독성 여부를 측정하여 세포에 대한 독성이 나타나지 않는 처리 농도에서 추출물 및 분획물의 항염증 활성을 확인하였다. 조추출물은 LPS로 유도된 NO 생성을 유의적으로 억제하는 효과를 나타내었으며, 주요 염증 유발인자인 iNOS와 COX-2의 발현 또한 효과적으로 억제하였다. 분획물의 NO 생성 억제효과는 85% aq. MeOH> n-BuOH >n-hexane > H₂O의 순으로 나타났으며, 세포내 전사수준에서 염증관련 유전자의 발현 억제율은 H₂O 분획 처리군에 비해 85% aq. MeOH, n-BuOH 및 n-hexane 분획 처리군에서 높게 나타났다. 이상의 결과로부터 항염증 활성이 가장 높게 나타난 85% aq. MeOH 분획층으로 부터 염증억제 효과가 있는 유효 성분의 분리가 기대된다. As a part of ongoing research to elucidate and characterize antiinflammatory nutraceuticals, the crude extracts from Atriplex gmelinii C. A. Mey. and their solvent-partitioned fractions were tested for their antiinflammatory potential in lipopolysaccharide (LPS)-stimulated RAW 264.7 mouse macrophages. The crude extracts of A. gmelinii C. A. Mey. were fractioned according to polarity with n-hexane, 85% aqueous methanol (85% aq. MeOH), n-butanol, and H₂O. Their antiinflammatory activities were investigated in LPS-induced inflammation in mouse macrophages by measuring nitric oxide (NO) generation and mRNA expression of inflammation mediators, namely, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and IL-6. As a result, we confirmed that the crude extracts of A. gmelinii C. A. Mey. inhibited LPS-stimulated NO production and mRNA expression of iNOS and COX-2 as important inflammatory factors. The inhibition of NO production through the downregulation of important inflammatory factors such as iNOS, COX-2, IL-1β, and IL-6 was found by treatment with all solvent-partitioned fractions. Among all tested fractions, 85% aq. MeOH showed the strongest antiinflammatory response. Based on the current results, A. gmelinii C. A. Mey. was suggested to possess natural antiinflammatory components, indicating that it could be used as a valuable source of antiinflammatory substances.

유기인 계열 독성물질 분해를 위한 바이오스캐빈저 최신 연구 동향

김희정 ( Heejeong Kim ),정근홍 ( Keunhong Jeong ),계영식 ( Young-sik Kye ) 한국공업화학회 2020 공업화학 Vol.31 No.2

최근 몇 년간 유기인 계열 독성물질이 민간인을 대상으로 사용되어 전 세계적으로 큰 위협이 되고 있다. 독성물질에 대한 예방이 불가능한 현 치료대책 대신, 보다 개선된 치료 대책으로서의 바이오스캐빈저에 대한 연구가 활발히 진행됐다. 바이오스캐빈저는 유기인 계열 독성물질이 인체 내 표적 기관에 도달하기 전, 독성물질 자체를 비활성 상태로 전환하거나 독성물질과 기질 간의 결합을 차단함으로써 중독을 예방하는 단백질 및 효소를 일컫는다. 특히 독성물질을 분해하는 과정에서 활성 상태를 유지함으로써 적은 양의 단백질로도 독성물질의 중독을 빠르게 치료하는 촉매성 바이오스캐빈저 개발에 많은 노력이 투여되어 왔다. 본 리뷰에서는 촉매성 바이오스캐빈저 개발을 위해 분자진화 및 단백질 공학 기술을 적용한 최신 연구들에 대해 소개하고, 끝으로 이러한 효소들을 임상적으로 승인된 약으로 개발하기 위해 남은 몇 가지 과제들을 간단히 제시할 것이다. In recent years, toxic organophosphorus compounds (OPs) have been used for civilians, becoming a great threat to the world. Alternative to the current treatment policy unpredictable for any prevention, researches on bioscavenger as an improved treatment have been actively conducted. Bioscavengers refer to proteins and enzymes that prevent intoxication by inactivating or binding toxic OPs before they reaches the target. In particular, extensive efforts have been made to develop catalytic bioscavengers that quickly detoxify OPs even with a small dose of the protein by performing multiple binding and hydrolysis processes with OPs. This review introduces the latest studies and results for developing catalytic bioscavengers using molecular evolution and protein engineering techniques. We will briefly present some of the remaining challenges on developing enzymes into clinically approved drugs.