• Journal of Ginseng Research
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• 제36권4호
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• pp.449-460
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• 2012

Plants have versatile detoxification systems to encounter the phytotoxicity of the wide range of natural and synthetic compounds present in the environment. Glutathione S-transferase (GST) is an enzyme that detoxifies natural and exogenous toxic compounds by conjugation with glutathione (GSH). Recently, several roles of GST giving stress tolerance in plants have demonstrated, but little is known about the role of ginseng GSTs. Therefore, this work aimed to provide further information on the GST gene present in Panax ginseng genome as well as its expression and function. A GST cDNA (PgGST) was isolated from P. ginseng cDNA library, and it showed the amino acid sequence similarity with theta type of GSTs. PgGST in ginseng plant was induced by exposure to metals, plant hormone, heavy metals, and high light irradiance. To improve the resistance against environmental stresses, full-length cDNA of PgGST was introduced into Nicotiana tabacum. Overexpression of PgGST led to twofold increase in GST-specific activity compared to the non-transgenic plants, and the GST overexpressed plant showed resistance against herbicide phosphinothricin. The results suggested that the PgGST isolated from ginseng might have a role in the protection mechanism against toxic materials such as heavy metals and herbicides.

• Bulletin of the Korean Chemical Society
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• 제33권6호
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• pp.1861-1866
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• 2012

The new semiconducting copolymers with 4,4-dialkyl-$4H$-cyclopenta[2,1-$b$:3,4-$b^{\prime}$]dithiophene and 2,2-dimethyl-$2H$-benzimidazole units were synthesized. The fused aromatic rings, such as cyclopentadithiophene (CPDT) unit, can make the polymer backbone more rigid and coplanar, which induces long conjugation length, narrow band gap, and strong intermolecular ${\pi}-{\pi}$ interaction. The stacking ability was controlled through attaching of linear or branched alkyl side chains. The spectra of PEHCPDTMBI and PHCPDTMBI in the solid films show absorption bands with maximum peaks at 401, 759 and 407, 768 nm, and the absorption onsets at 925 and 954 nm, corresponding to band gaps of 1.34 and 1.30 eV, respectively. The devices comprising PHCPDTMBI with $TiO_X$ showed a $V_{OC}$ of 0.39 V, a $J_{SC}$ of 1.14 $mA/cm^2$, and a $FF$ of 0.34, giving a power conversion efficiency of 0.15%. The PHCPDTMBI with linear alkyl chain on CPDT shows good solubility in organic solvent with higher PCE value than that of PEHCPDTMBI.

• 방사선산업학회지
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• 제10권1호
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• pp.1-5
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• 2016

In this study, the effect of high-energy proton irradiation on the optical properties of polyacrylonitrile (PAN) films was investigated. PAN thin films spin-coated on a substrate were irradiated 150 keV proton ions at various fluences. The changes in the chemical structure and optical properties were investigated by FT-IR and UV-vis spectroscopy. The results of the FT-IR analysis revealed that the cyclization reaction took place by proton irradiation and the degree of cyclization increased with an increasing fluence. Based on the UV-vis analysis, the optical band gap of PAN decreased from 2.84 to 2.52 eV with an increasing fluence due to the formation of carbon clusters by proton irradiation. In addition, the number of carbon atoms per carbon cluster and the number of carbon atoms per conjugation length were found to be increased with an increasing fluence.

• 한국작물학회지
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• 제38권6호
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• pp.545-553
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• 1993

벼 기계이앙을 위한 어린모 육묘에서 뿌리엉킴촉진에 탁원한 효과가 있는 metalaxyl의 묘 뿌리분화 및 신장생장에 관한 일부 생리적 기작을 밝히고자 metalaxyl 침지처리에 따른 어린모의 근활력, 발근력, 아미노산 함량 변화, 광합성 및 엽록소함량등을 조사ㆍ분석한 결과는 다음과 같다. 1. metalaxyl(25%, 수화제) 200ppm에 침지처리한 어린모는 무처리에 비하여 전육묘기간중에 근활력이 높았으며 특히 파종후 10～13일에 현저하게 높았다. 2. metalaxyl 200ppm에 종자를 침지처리한 어린모에서 재발생된 관근의 길이는 무처리보다 유의적으로 길었으며, 뿌리의 신장을 촉진시켰다. 3. metalaxyl 200ppm에 종자를 침지처리한 어린모에서 재발생된 관근의 수는 무처리와 비슷한였으나, 관근에서 발생된 분지근(측근)의 수는 2～3배 증가되어 분기근의 분화를 촉진시켰다. 4. 어린모 뿌리의 alanine함량은 metalaxyl처리에 의하여 현저히 증가되었으며, alanine 함량과 근활력, 또 metalaxyl 농도와 분지근수 간에는 정의 상관관계가 있었다. 5. metalaxyl 침지처리는 어린모 뿌리에서 거의 모든 종류의 아니노산 함량을 증가시켰다. 6. metalaxyl처리는 어린모 체내의 엽록소 및 전질소 함량을 높이고, 광합성량을 증가시켰다.