• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1045-1052
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• 1996

The effects of G-T mismatches on thermal stability, the base-pair lifetime and the global structure of a d(GCGTGCGC)2 duplex were studied by using 1H NMR, UV and CD spectroscopy. The existence of G-T mismatches was found to cause a noticeable change in the chemical environment of imino protons associated with significant decrease in the base-pair lifetime at the mismatched site as well as in thermal stability of the duplex itself. The melting transition of d(GCGTGCGC)2 was not cooperative at all at 100 mM or lower concentration of NaCl, but became cooperative at 500 mM or higher NaCl concentration. The melting temperature (Tm) of this duplex was 32℃ at 500 mM concentration of NaCl, which is much lower than that of d(GCGCGCGC)2 at the same NaCl concentration. This suggests that the decrease in stability may be ascribed to the decrease in the base-pair lifetime and the deviation from the normal structure due to the G-T mismatches. Adding berenil to d(GCGTGCGC)2 caused no observable change in the global structure but the large decrease in the base-pair lifetime and the stability of the duplex.

• Particle and aerosol research
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• v.6 no.3
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• pp.131-138
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• 2010

Flexible electronics are the electronics on flexible substrates such as a plastic, fabric or paper, so that they can be folded or attached on any curved surfaces. They are currently recognized as one of the most innovating future technologies especially in the area of portable electronics. The conventional vacuum deposition and photolithographic patterning methods are well developed for inorganic microelectronics. However, flexible polymer substrates are generally chemically incompatible with resists, etchants and developers and high temperature processes used in conventional integrated circuit processing. Additionally, conventional processes are time consuming, very expensive and not environmentally friendly. Therefore, there are strong needs for new materials and a novel processing scheme to realize flexible electronics. This paper introduces current research trends for flexible electronics based on (a) nanoparticles, and (b) novel processing schemes: nanomaterial based direct patterning methods to remove any conventional vacuum deposition and photolithography processes. Among the several unique nanomaterial characteristics, dramatic melting temperature depression (Tm, 3nm particle~$150^{\circ}C$) and strong light absorption can be exploited to reduce the processing temperature and to enhance the resolution. This opens a possibility of developing a cost effective, low temperature, high resolution and environmentally friendly approach in the high performance flexible electronics fabrication area.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1638-1642
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• 2012

A series of poly (lactic acid) (PLA) and poly (ethylene glycol) (PEG) tri and multiblock copolymers with relatively high molecular weights were synthesized through the coupling reaction between the bis(acyl chloride) of carboxylated PLA and mono or dihydroxy PEG. The coupling reaction and the copolymer structures were monitored by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). The melting temperature (Tm) of PEG blocks decreased with the presence of PLA sequences attaching to PEG blocks. The CMC values were determined to be 10-145 mg/L depending on the length of PLA and PEG blocks and the structure of the block copolymers.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2005.09a
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• pp.147-150
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• 2005

Proper PCR primer design determines the success or failure of Polymerase Chain Reaction (PCR) reactions. In this project, we develop GENE-PRIMER, a genomes specific PCR primer design program that is amenable to a genome-wide scale. To achieve this, we incorporated various parameters with biological significance into our program, namely, primer length, melting temperature of primers Tm, guanine/cytosine (GC) content of primer, homopolymeric runs in primer and self-hybridization tendency of primer. In addition, BLAST algorithm is utilized for the purpose of primer specificity check. In summary, selected primers adhered to both physico-chemical criteria and also display specificity to intended binding site in the genome.

• Bulletin of the Korean Chemical Society
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• v.23 no.8
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• pp.1073-1077
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• 2002

Binding of dodecyl trimethylammonium bromide (DTAB) to human and bovine hemoglobin and globin samples has been investigated in 50 mM glycine buffer pH = 10, I = 0.0318 and 300 K by equilibrium dialysis and temperature scanning spectrophotometry techniques and method for calculation of average hydrophobicity. The binding data has been analyzed, in terms of binding capacity concept $({\theta})$, Hill coefficient (nH) and intrinsic Gibbs free energy of binding $({\Delta}Gbv).$ The results of binding data, melting point (Tm) and average hydrophobicity show that human hemoglobin has more structural stability than bovine hemoglobin sample. Moreover the results of binding data analysis represent the systems with two and one sets of binding sites for hemoglobin and globin, respectively. It seems that the destabilization of hemoglobin structure due to removal of heme group, is responsible of such behavior. The results indicating the removal of heme group from hemoglobin caused the depletion of first binding set as an electrostatic site upon interaction with DTAB and exposing the hydrophobic patches for protein.

• BMB Reports
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• v.42 no.6
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• pp.373-379
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• 2009

5-Hydroxyuridine (5-OHU) is a major lesion of uridine and cytosine produced in RNA by various chemical oxidants. To elucidate its biochemical and biophysical effects on RNA replication, the site-specifically modified oligoribonucleotides containing 5-OHU were synthesized with C5-hydroxy-5'-ODMTr-2'-TBDMS-uridine phosphoramidite using automated solid phase synthesis. The base-pairing properties of nucleotides opposite 5-OHU in 24 mer oligoribonulcleotides with dNTP were studied using three reverse transcriptases (Super-$Script^{TM}II$-, AMV-, MMLV-RT) in cDNA synthesis. Adenine as well as guanine was incorporated preferentially by all reverse transcriptases. In the UV-melting temperature experiment, the results from the relative stabilities of the base pairs were A : 5-OHU > G : 5-OHU > T : 5-OHU $\approx$ C : 5-OHU. Circular Dichroism (CD) studies showed that DNA-RNA containing 5- OHU heteroduplexes exhibit a similar conformation between the A-type RNA and B-type DNA. These results suggest that 5- OHU from oxidative damage was mainly influenced by adenine mismatch.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.215-224
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• 1988

Block copoly(L-lactide-${\gamma}$-benzyl-L-glutamate)was synthesized from L-lactide by cationic ring opening polymerization and ${\gamma}$-benzyl-L-glutamate N-carboxy anhydride by introducing amino group terminated poly(L-lactide). L-lactide was polymerized in the presence of stannous octate at $110^{\circ}C$ and ${\gamma}$-benzyl- L-glutamate was polymerized in the presence of NaH at room temperature. The synthesized monomers and copolymers were identified by IR and NMR. The Itermal properties of the copolymers were characterized by differential scanning calorimetry and thermogravimetry. The thermal stability and melting temperature(Tm) of the block copolymers were measured and discussed. The activation energies of thermal decomposition for the block copoly(L-lactide-${\gamma}$ benzyl-L-glutamate) were evaluated from the thermogravimetric data by Freeman and Carroll method.

• Journal of the Korean Applied Science and Technology
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• v.16 no.3
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• pp.255-262
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• 1999

The new copolymers which contain flexible spacers in main chain were prepared and their properties were studied. the copolymers were synthesized in the melt polymerization melted from diacetoxynaphthalene isomers, ${\alpha},{\omega}bis(4-carboxyphenoxy)$ alkanes and p-acetoxy benzoic acid in the molar ratio of 1:1:2 and characterized for the effects of structure of naphthalenediol isomer moieties and the spacers on thermal crystalline and liquid crystalline properties of the resulting polymers. Diacetoxy naphthalene isomers were used 1. 5-,1. 6-,2. 6-and 2. 7-disubstituted ones and the spacers was either tetramethylene or decamethylene. The polymer was characterized by elemental and spectropic analysis, differential scanning calorimetry (DSC) on a polaring microscope, wide-angle X-ray diffractometry and thermogravimetry (TGA). There glass transition temperatures (Tg) and melting temperature (Tm) on the structure of the naphthalenediol isomer moieties and the length of the spacers. The presence of spacers was found to the helpful in crystallization of 1. 6-naphthalenediol copolyesters. The presence of amide group in the backbone chain of polymer was found to increase transition temperature, crystallization, thermal stability of polymers but to decreas solubility.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2170-2174
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• 2005

Selective Laser Sintering (SLS) is a useful rapid prototyping technique for the manufacture of three dimensional (3D) solid objects directly from a scanning data. A new approach called a Selective Multi-Laser Sintering (SMLS) system has been developed at Korea Institute Machinery & Materials (KIMM) as an industrial type SFFS. This SMLS machine is built with a frame, heaters, nitrogen supply part, laser system. This system uses the dual laser and 3D scanner made in $Solutionix^{TM}$ to improve the precision and speed for large objects. The three-dimensional solid objects are made of polyamide powder. The investigation on each part of SMLS system is performed to determine the proper theirs design and the effect of experimental parameters on making the 3D objects. The temperature of the system has a great influence on sintering the polymer. Because the stability of the powder temperature prevents the deformation of each layer, the controls of the temperature in both the system and the powders are very important during the process. Therefore, we simulated the temperature distribution of build room using the temperature analysis with ANSYS program. Selected radiant heater is used to raise temperature of powder to melting point temperature. The laser parameters such as scan spacing, scan speed, laser power and laser delay time affect the production the 3D objects too. The combination of the slow scan speed and the high laser power shows the good results without the layer curling. The work is under way to evaluate the effect of experimental parameters on process and to produce the various objects. We are going to experiment continuously to improve the size accuracy and surface roughness.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.56-56
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• 2020

감초는 다년생 콩과(Leguminocae) 식물로 국내에서 시중가격이 높은 만주감초가 일부 재배되고 있다. 우리나라에서 감초 재배법이 불완전한 상황에서 한반도의 기후변화에 의한 온도 상승은 약용작물의 생산 및 품질에 많은 영향을 미칠 것으로 예상되므로 본 연구에서는 재배환경 중 온도 조건만 조절할 수 있는 온도구배터널(temperature gradient tunnel system)을 이용하여 4개의 T1(외기온도+0.5~1.3℃), T2(+1.3~2.2℃), T3(+2.2~3.2℃), T4(+3.2~4.0℃) 처리로 온도구배 하여 4년생 만주감초(Glycyrrhiza uralensis F.)를 재배하였다. 지하부가 오래된 모주와 신초1의 경우 저온(T1)과 중간구간(T2, T3)에서 초장과 총화수가 우세하였고, 번식이 가장 늦은 신초2의 경우 중간구간(T2, T3)에서의 생육 및 개화반응이 뚜렷했다. 각 온도처리구마다 3개의 감초 개체를 선발하여 모주의 정단으로부터 5개의 성엽을 채취하였다. Reverse transcription quantitative PCR (RT-qPCR)은 AccuPower® GreenStar^TM RT-qPCR Master Mix (Bioneer, Korea)를 이용하여 진행되었다. Primer 디자인은 NCBI Primer-blast 프로그램을 사용해 제작하였고 ABI StepOne real time system (Applied Biosystem)의 melting curve analysis에서 one-peak test를 통해 gene specific primer임을 확인하였다. 각 온도처리구의 감초 잎에서 RNA를 추출하였고, RT-qPCR을 통해 감초의 유전자 발현양상을 비교, 분석하였다. Phytochrome interacting factor 4 (PIF4)는 식물 호르몬을 유발하는 전사조절을 조정함으로써 고온 신호전달에 핵심적인 역할을 수행한다. 활성화된 Phytochrome B(PhyB)는 PIF4의 활성을 억제한다고 알려졌다. Eukaryotic initiation factors(eIFs)는 mRNA 번역 개시인자로 유전자 발현과 특정 단백질 생산을 조절하는 역할을 한다. 본 결과는 온도조건에서 반응하는 생리적 변화를 전사체 수준에서 조사 분석하여 생리해석의 기초자료로 활용, 국내 감초 재배를 위한 환경조건 구명 및 적지 선정 기초자료로서 활용을 기대한다.