• 공업화학
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• 제31권3호
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• pp.284-290
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• 2020

Energetic thermoplastic elastomers (ETPEs) based on glycidyl azide polymer (GAP) and carboxylated GA copolymers [GAP-ETPE and poly(GA-carboxylate)-ETPEs] were synthesized using isophorone diisocyanate (IPDI), dibutyltin dilaurate (DBTDL), 1,4-butanediol (1,4-BD), and soft segment oligomers such as GAP and poly(GA-carboxylate). The synthesized GAP-ETPE and poly(GA-carboxylate)-ETPEs were characterized by Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), universal testing machine (UTM), calorimetry and sensitivity towards friction and impact. DSC and TGA results showed that the introduction of carboxylate group in GAP helped to have better thermal properties. Glass transition temperatures of poly(GA-carboxylate)-ETPEs decreased from -31 ℃ to -33 ℃ compared to that of GAP-ETPE (-29 ℃). The first thermal decomposition temperature in poly(GA_0.8-octanoate_0.2)-ETPE (242 ℃) increased in comparison to that of GAP-ETPE (227 ℃). Furthermore, from calorimetry data, poly(GA-carboxylate)-ETPEs exhibited negative formation enthalpies (-6.94 and -7.21 kJ/g) and higher heats of combustion (46713 and 46587 kJ/mol) compared to that of GAP-ETPE (42,262 kJ/mol). Overall, poly(GA-carboxylate)-ETPEs could be good candidates for a polymeric binder in solid propellant due to better energetic, mechanical and thermal properties in comparison to those of GAP-ETPE. Such properties are beneficial to application and processing of ETPE.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2179-2182
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• 2014

• 한국자원식물학회지
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• 제23권6호
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• pp.526-534
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• 2010

Genomes of clusters of related eukaryotes are now being sequenced at an increasing rate. In this paper, we developed an accurate, low-cost method for annotation of gene prediction and exon-intron structure. The gene prediction was adapted for delta 1-pyrroline-5-carboxylate-synthetase (p5cs) gene from China wild-type of the halophytic Leymus chinensis (Trin.), naturally adapted to highly-alkali soils. Due to complex adaptive mechanisms in halophytes, more attentions are being paid on the regulatory elements of stress adaptation in halophytes. P5CS encodes delta 1-pyrroline-5-carboxylate-synthetase, a key regulatory enzyme involved in the biosynthesis of proline, that has direct correlation with proline accumulation in vivo and positive relationship with stress tolerance. Using analysis of reverse transcription-polymerase chain reaction (RT-PCR) and PCR, and direct sequencing, 1076 base pairs (bp) of cDNA in length and 2396 bp of genomic DNA in length were obtained from direct sequencing results. Through gene prediction and exon-intron structure verification, the full-length of cDNA sequence was divided into eight parts, with seven parts of intron insertion. The average lengths of determinated coding regions and non-coding regions were 154.17 bp and 188.57 bp, respectively. Nearly all splice sites displayed GT as the donor sites at the 5' end of intron region, and 71.43% displayed AG as the acceptor sites at the 3' end of intron region. We conclude that this method is a cost-effective way for obtaining an experimentally verified genome annotation.

• 공업화학
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• 제32권3호
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• pp.260-267
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• 2021

본 연구에서는 코코넛 오일로부터 카르복실레이트계 음이온 계면활성제 SLEC-3을 합성하였으며, 합성된 계면활성제의 구조를 FT-IR, ¹H-NMR 및 ¹³C-NMR 분석을 통하여 확인하였다. 합성한 계면활성제 SLEC-3에 대하여 임계 마이셀 농도, 정적 및 동적 표면장력, 유화력, 거품 안정성 등의 계면 물성을 측정한 결과, 기존 세제 제품에서 널리 사용되는 음이온 계면활성제 SLES와 비교하여 계면 활성이 보다 우수하고 계면 에너지를 낮추는데 더 효과적이었다. 또한 SLCE-3에 대한 생분해성, 급성 경구 독성 및 급성 피부자극 시험을 실시한 결과, 저자극 및 저독성을 가지고 있기 때문에 세제 및 세정제 제품에 적용할 수 있을 것으로 판단되었다.

• 대한화학회지
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• 제32권3호
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• pp.243-248
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• 1988

수용액에서 몇가지 란탄 착화합물의 hypersensitive 전이대를 연구하였다. 리간드의 염기도$(pK_a)$와 란탄 착화합물의 hypersensitive 전이대의 진동자 세기 사이에 정립된 선형 관계에 근거를 두고, 금속-리간드 결합간에 존재하는 공유 결합성을 anthranilate, pyrazine-2-carboxylate, 및 pyruvate 착화합물에 대해서 논하였다.

• Bulletin of the Korean Chemical Society
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• 제20권12호
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• pp.1475-1478
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• 1999

Ligand field calculations have been performed based on the data from the absorption and low temperature sharp-line excitation spectra of fac-Cr(gly)₃, fac-Cr(L-serine)₃ · 2H₂O and fac-Cr(L-leucine)₃·2H₂O. The optimized ligand field parameters for all complexes show that the carboxylate and the amino groups are moderate σ-donor. The values of $e_{{\pi}O}$ are typical of other complexes with carboxylate ligands. However, the π-interaction of carboxylic oxygen to the chromium in serinato complex is much weaker than that of other complexes. The inclusion of π-anisotropy is necessary to adequately explain the large doublet splittings.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4137-4140
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• 2011

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.70-70
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• 2003

Active sites and substrate bindings of 1-aminoxyclopropane-1-carboxylate oxidase (MD-ACO1) catalyzing the oxidative conversion of ACC to ethylene have been determined based on site-directed mutagenesis and comparative modeling methods. Molecular modeling based on the crystal structure of Isopenicillin N synthase (IPNS) provided MD-ACO1 structure. MD-ACO1 protein folds into a compact jelly roll shape, consisting of 9 ${\alpha}$-helices, 10 ${\beta}$-strands and several long loops. The MD-ACO1/ACC/Fe(II)/Ascorbate complex conformation was determined from automated docking program, AUTODOCK. The MD-ACO1/Fell complex model was consistent with well known binding motif information (HIS177-ASP179-HIS234). The cosubstrate, ascorbate is placed between iron binding pocket and Arg244 of MD-ACO1 enzyme, supporting the critical role of Arg244 for generating reaction product. These findings are strongly supported by previous biochemical data as well as site-directed mutagenesis data. The structure of enzyme/substrate suggests the structural mechanism for the biochemical role as well as substrate specificity of MD-ACO1 enzyme.

• 한국해양바이오학회지
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• 제13권1호
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• pp.28-47
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• 2021

Pectin is a natural polysaccharide and biopolymer that serves as a structural component of plant tissues' primary cell walls. Pectin is primarily composed of D-galacturonic acid linked by α-1, 4-glycosidic linkage and is further classified by the ratio of esterified galacturonic acid groups known as degree of esterification (DE). Pectin that contains more than half of its carboxylate units as methyl esters is known as a high methyl (HM) ester. Conversely, pectin that has less than half of its carboxylate units as methyl esters is known as a low methyl (LM) ester. Pectin has various bioactive properties, including anticancer, anti-inflammatory, antioxidant, antidiabetic, anticholesterol, antitumoral, and chemopreventive properties. Moreover, pectin is a useful biopolymer in biomedical applications. Biomedical engineering, which is founded on research aimed to improve the quality of life using new materials and technologies, is typically classified according to the use of hydrogels, nanofiber mats, and nanoparticles. This paper reviews the progress of recent research into pectin-based biomedical applications and the potential future biomedical applications of marine-derived pectin.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3255-3260
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• 2011

Two novel binuclear metal-organic coordination complexes $[Cd_2(L)_2(bpy)_2(H_2O)_2]{\cdot}6H_2O$ (1), $[Cd_2(L)_2(phen)_2-(H_2O)_2]{\cdot}2H_2O$ (2) (where L = 2-methylquinoline-3,4-dicarboxylate dianion, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) have been synthesized under hydrothermal conditions and characterized by single crystal Xray diffraction, spectral method (IR), elemental analysis and thermal gravimetric analysis (TGA). Both 1 and 2 consist of two Cd(II) atoms bridged by two monoatomic bridging carboxylate groups from two L ligands, and the second carboxylate group of each L is monodentately coordinated to Cd(II), creating a sevenmembered chelating ring. The coordination at each metal nucleus is completed by a water molecule and a chelating bidentate molecule. The 3D structures of the complexes are stabilized by ${\pi}-{\pi}$ stacking interactions and hydrogen-bonds.