• YAKHAK HOEJI
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• v.31 no.2
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• pp.116-125
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• 1987

It is still difficult and time consuming to obtain cDNA sequences that contain the entire nucleotide sequence of the corresponding mRNA. A rapid and high efficient cloning method to obtain full-length cDNA segments is thus developed. The cloning procedure described here consists of the construction of oligo(dT)-tailed vector primer using pWR34 plasmid, polyadenylation of mRNA-cDNA heteroduplex using terminal deoxytransferase, and replacement of MRNA strand with DNA by RNase H and DNA polymerase I. The restriction endonuclease analysis shows that the size of inserted-cDNA is in the range of 1.5~4.0 kb long suggesting that most of cloned cDNA are full-length or nearly full-length cDNA. The plasmid-DNA recombinants obtained were 4$\times$$10^5$~$10^{6}$ per $\mu\textrm{g}$ of rat liver poly (A$^+$)mRNA, which is 4 to 10 fold higher cloning efficiency in comparison to the presently used methods for full-length cDNA cloning. The results indicate that the described cloning system is much simpler, less time consuming, and very efficient cloning method to construct a cDNA library.

• Journal of the Korean Electrochemical Society
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• v.3 no.1
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• pp.25-30
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• 2000

The relation between the phase-shift profile for the intermediate frequencies and the Langmuir adsorption isotherm at the poly-$Pt/0.1\;M\;H_2SO_4$ aqueous electrolyte interface has been studied using ac impedance measurements, i.e., the phase-shift methods. The suggested interfacial equivalent circuit consists of the serial connection of the electrolyte resistance ($R_S$), the faradaic resistance $(R_F)$ and the equivalent circuit element $(C_P)$ of the adsorption pseudocapacitance $(C_\varphi)$. The delayed phase shift $(\varphi)$ depends on both the cathode potential (E) and frequency (f), and is given by $\varphi=-tan^{-1}[1/2{\pi}f(R_s+R_F)C_p]$. The phase-shift profile $(\varphi\;vs.\;E)$ for the intermediate frequency (ca. 6Hz) can be used as an experimental method to determine the Langmuir adsorption isotherm (9 vs. E). The equilibrium constant (K) for H adsorption and the standard free energy $({\Delta}G_{ads})$ of H adsorption at the poly-$Pt/0.1\;M\;H_2SO_4$ electrolyte interface are $1.8\times10^{-4}\;and\;21.4kJ/mol$, respectively. The H adsorption is attributed to the over-potentially deposited hydrogen (OPD H).

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.195.2-195
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• 1996

acs gene cloning was constructed by subcloning the 2.2-kb MunI-MunI restriction fragment of 638 and 639 which include acs gene from the kohara phage into the unique EcoRI site of pUC18 and pJM9131 containing the PHA biosynthesis genes. Then recombinant E. coli fadRatoC(Con) mutants containing the polyhydroxyalkanoate(PHA) biosynthesis genes are able to incoporate s significant levels of 3-hydroxyvalerate (3HV) into the copolymer [P(3HB-co-3HV)]. Quantitative determination of PHB and P(3HB-co-3HV) was performed by gas-chromatographic analysis of extracts obtained from methanolysis of lyophilized cells.

• Bulletin of the Korean Chemical Society
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• v.2 no.4
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• pp.142-147
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• 1981

A blend polymeric system composed of poly(methyl methacrylate) (PMMA or PM) and polystyrene (PS) dissolved in chloroform was rheologically studied. The viscosities ${\eta}_{bl}$ of the blend system with various blending ratios ${\chi}$ changing from zero (pure PS solution) to unity (pure PMMA solution) were measured at $25{\circ}C$ as a function of shear rates ${\dot{s}}$ by using a Couette type viscometer. ${\eta}_{bl}$ at a given ${\dot{s}}$ decreased exponentially with ${\chi}$ reaching asymptotic constant value of ${\eta}_{bl}$ ; ${\eta}_{bl}$ at a given ${\chi}$ is greater at a smaller ${\dot{s}}$. These results are explained by using Ree-Erying's theory of viscosity, ${\eta}_{bl}=(x_1{\beta}_1/{\alpha}_1)_{b}_1＋ (x_2{\beta}_2/{\alpha}_2)_{bl}[sinh^{-1}{\beta}_2(bl) {\dot{s}}]/{\beta}_2(bl){\dot{s}}$. The Gibbs activation energy ${\Delta}G_i^\neq$(i = 2 for non-Newtonian units) entering into the intrinsic relaxation time ${\beta}$ is represented by a linear combination ${\Delta}G_i^\neq(bl) ={\chi}{\Delta}G_i^{\neq}_{iPM}+(1-{\chi}){\Delta}G_i^{\neq}_{iPS}$;the intrinsic shear modulus$[[\alpha}_i]^{-1}$ is also represented by $[{\alpha}_i(bl)]^{-1}={\chi}[{\alpha}_{iPM}]^{-1}+(1-{\chi})[{\alpha}_{iPS}]^{-1}$ and the fraction of area on a shear surface occupied by the ith flow units $x_i(bl)$ is similarly represented, i.e., $x_i(bl) = {\chi}x_{iPM}+(1-{\chi})x_{iPS}$. By using these ideas the Ree-Eyring equation was rewritten which explained the experimental results satisfactorily.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1140-1146
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• 2006

Ceramide analogs are potential chemotherapeutic agents. We report that a ceramide analog induces apoptosis in human prostate cancer cells. The ceramide analog induced cell death through an apoptotic mechanism, which was demonstrated by DNA fragmentation, the cleavage of poly ADP ribose polymerase (PARP), and a loss of membrane asymmetry. Treating the cells with ceramide analog resulted in the release of various proapoptotic mitochondrial proteins including cytochrome c and Smac/DIBLO into the cytosol, and a decrease in the mitochondrial membrane potential. In addition, the ceramide analog decreased the phospho-Akt and phospho-Bad levels. The expression of the antiapoptotic Bcl-2 decreased slightly with increasing Bax to Bcl-2 ratio. These results suggest that the ceramide analog induces apoptosis by regulating multiple signaling pathways that involve the mitochondrial pathway.

• Elastomers and Composites
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• v.54 no.4
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• pp.286-293
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• 2019

In this study, flexible poly(ethylene-ter-1-hexene-ter-divinylbenzene) was prepared using four types of metallocene catalysts (rac-Et(Ind)₂ZrCl₂, rac-SiMe₂(Ind)₂ZrCl₂, rac-SiMe₂(2-Me-Ind)₂ZrCl₂, (C₅Me₅)TiCl₂[O-2,6-ⁱPr₂(C₆H₃)]) and two types of borate catalysts (trityl tetrakisborate and dimethylanilinium tetrakisborate). The yield, catalytic activity, molecular weight, structure, composition, and thermal properties of the terpolymers prepared using the various catalysts and cocatalyst systems were evaluated. Epoxidation of the terpolymers was successfully performed and this transformation was studied by ¹H NMR and FTIR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.220-223
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• 1995

Stable polyion-complexed polymeric monolayrers were prepared by spreading perfluoroalkyl monomaleatd copolymers. C$_2$F$\_$8/MA-VE$_2$ and C$_2$F$\_$8/Mv-VE$_3$ on aqueous poly(allylamine) subphase. The monolayer properties have been studied by the surface pressure-area($\pi$-A) isotherms. The C$_2$F$\_$8/MA-VE$_3$containing longer oligoethyleneglycol pendant showed more expaned monolayer phase than the C$_2$F$\_$8/MA-VE$_2$ The polyion-complexed monolayers were transferable on various substrates, and the resulting Langmuir-Blodgett(LB) films were characterized b ET-IR spectroscopy and scanning electron microscopy(SEM) Two-dimensional crosslinking to from a polymer network was achieved by amide formation through heat treatment under vacuum with concurrent removel of perfluoroalkyl tails. SEM observation of this film ona porous membrane filter showed that the four layer film was sufficiently stable to cover the filter pore size of 0.1$\mu\textrm{m}$. The C$_2$F$\_$8/MA-VE$_3$revealed better covering capability than the C$_2$F$\_$8/MA-VE$_2$Immersion of this film in water or in benzend did not cause any change in its appearance and in FT-IR spectra.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1592-1594
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• 2003

This paper presents the deposition and characterization of microcrystalline silicon(${\mu}c$-Si:H) films by HWCVD(Hot-wire Chemical Vapor Deposition) method at low substrate($300^{\circ}C$). The filament temperature, pressure and $SiH_4$ concentration were determined to be a critical parameter for the deposition of poly-Si films. Series A was deposited under the conditions of $1380^{\circ}C$(Tf), 100 mTorr and $2{\sim}10%\{SC:SiH_4/(SiH_4+H_2)\}$ for 60 min. Series B was deposited under the conditions of $1400{\sim}1450^{\circ}(T_f)$, 30 mTorr and $2{\sim}12%$(SC) for 60 min. The physical characteristics were measured by Raman and FTIR spectroscopy, dark and photoconductivity measurements under AM1.5 illumination.

• Macromolecular Research
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• v.16 no.5
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• pp.446-456
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• 2008

A recent theoretical approach based on the coupling of both the Flory-Huggins (FH) and the Association Equilibria thermodynamic (AET) theories was modified and adapted to study the miscibility properties of a multi-component system formed by two polymers (a proton-donor and a proton-acceptor) and a proton-acceptor solvent, named copolymer(A)/solvent(B)/polymer(C). Compatibility between polymers was mainly attained by hydrogen-bonding between the hydroxyl group on the phenol unit of the poly(styrene-co-vinyl phenol) (PSVPh) and the carbonyl group of the biodegradable and environmentally friendly poly(3-hydroxybutyrate) (PHB). However, the self-association of PSVPh and specific interactions between the PSVPh and the H-acceptor group (an ether oxygen atom) of the epichlorohydrin (ECH) solvent were also established in a lower extension, which competed with the polymer-polymer association. All the binary specific interactions and their dependence with the system composition as well as with the copolymer content were evaluated and quantified by means of two excess functions of the Gibbs tree energy, ${\Delta}g_{AB}$ and ${\Delta}g_{AC}$. Experimental results from fluorescence spectroscopy were consistent with the theoretical simulations derived with the model, which could also be applied and extended to predict the miscibility in solution of any polymer blend with specific interactions.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1353-1354
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• 2007

폴리 실리콘 층의 유무에 따른 금속-옥사이드-반도체(MOS) 구조의 소자를 제작하였다. 터널링 산화막과 블로킹 산화막으로는 $Al_{2}O_{3}$ 층을 증착하였으며, 원자층 증착법을 이용하여 제작하였다. 터널링 산화막 층의 두께에 따른 I-V와 C-V 특성을 측정하였다. 전자들이 폴리 실리콘 층에 저장됨에 따라 N-형의 I-V 특성이 관찰되었다. C-V 측정 시에는 반시계 방향의 히스테리시스 특성을 나타내었으며, 전압이 증가할수록 플랫-밴드 전압 이동 폭이 더욱 증가하였다. 이러한 전기적 특성은 전압의 이동에 따른 전자들이 터널링 산화막 층을 통하여 폴리 실리콘 내부에 저장되기 때문이다. 이를 특성들은 폴리 실리콘의 전하 저장 가능성을 보여주는 것이며, 터널링 산화막 층의 두께에 따른 전기적 특성 변화도 관찰하였다.