• YAKHAK HOEJI
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• v.38 no.4
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• pp.455-461
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• 1994

Each nitrogen and oxygen site isotope enriched the cyclophosphamide metabolite phosphoramide mustard was synthesized. Reaction of N,N-bis(2-chloroethyl)phosphoramidic dichloride$[Cl_2P(O)N(CH_2CH_2Cl)_2]$ with benzyl alcohol and ammonia gave N,N-bis(2-chloroethyl)phosphorodiamidic acid phenylmethyl ester $[BzO(H_2N)P(O)N(CH_2CH_2Cl)_2]$. Catalytic hydrogenation of this benzyl ester followed by the addition of cyclohexylamine provided PM. Incorporation of $^{15}NH_3$ into this general scheme gave PM with a $^{15}NH_2$ moiety. Glycine-$^{15}N$ was converted to bis(2-chloroethyl)amine-$^{15}N$ hydrochloride which, in turn, provided for N,N-bis(2-chloroethyl)phosphorodiamidic-$^{15}N$ dichloride. Use of this compound in the general synthetic pathway yielded PM CHA with $^{15}N$ in the mustard moiety. $^{17}O$-Enriched PM was generated through the use of benzyl alcohol-$^{17}O$. To obtain the alcohol, labelled benzaldehyde was made by exchange with $^{17}OH_2$ and was then reduced with sodium borohydride.

• Journal of the Korean Ceramic Society
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• v.35 no.10
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• pp.1070-1077
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• 1998

Effect of current collecting layer on the cathode was characterized by AC impedance spectroscopy at 800$^{\circ}C$ under flowing air. LSM-YSZ composite cathode showed lower polarization resistance due to the in-crease of triple phase (LSM/YSZ/Pore) boundary length by incorporation of YSZ. Ohmic resistance {{{{ {R }_{1 } }} of LSM-YSZ was higher than that of pure LSM however because in-plane resistance of the cathode was fair-ly high due to its high specific resistivity. To reduce the in-plane resistance of LSM-YSZ cathode cathode side current collecting layer was required. Ohmic resistance {{{{ {R }_{1 } }} was reduced after forming LSM current col-lecting layer on the LSM-YSZ cathode. In case of pure LSM cathode the formation of Pt, or LSCO current collecting layer reduced polarization resistance {{{{ {R }_{p } }} but ohmic resistance {{{{ {R }_{1 } }} was relatively constant. After annealing of LSM cathode with Pt current collector at higher temperature polarization resistance {{{{ {R }_{p } }} was in-creased but ohmic resistance {{{{ {R }_{1 } }} was constant. These phenomena indicate that Pt or LSCo current col-lecting layers act as a catalytic layer for oxygen reduction of pure LSM cathode. LSCO current collector was effective in reducing the ohmic and polarization resistance of LSM-YSZ cathode.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.123-126
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• 2002

Lipoxygenase might be associated with seed deterioration by catalyzing the incorporation of molecular oxygen into fatty acids and generating free radicals. This study was performed to determine whether seed lipoxygenase activity would alter soybean seed longevity. In this study, germination percentage of lipoxygenase-lacking cultivar Jinpumkong2 (lx1lx1lx2lx2lx3lx3) was lower than that of Taekwangkong (Lx1Lx1Lx2Lx2Lx3Lx3). Segregation ratio for the three lipoxygenase isozymes of the F2-derived from the cross between Taekwangkong and Jinpumkong2 was fitted to 9 (Lx1Lx2Lx3) : 3 (Lx1Lx2lx3) : 3 (lxllx2Lx3) : 1 (lx1lx2lx3), suggesting the tight linkage between the Lx1 and Lx2 loci. Germination percentages varied widely but not differed among lipoxygenase isozyme types of F$_3$ seeds before and after accelerated aging. Seed coat of Jinpumkong2 was damaged severely following accelerated aging, whereas that of Taekwangkong was not. Thus, seed of lipoxygenase-lacking soybean cultivar, Jinpumkong2 showed greater deterioration compared with that of the normal Taekwangkong. However, the presence or absence of lipoxygenase activity had no effect on soybean germination.

• Elastomers and Composites
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• v.54 no.1
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• pp.22-29
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• 2019

Chitosan-polyvinyl alcohol (PVA) -bamboo charcoal/silica (CS-PVA-BC/SI) hybrid fillers with compatibilized styrene-butadiene rubber (SBR) composites were fabricated by the interpenetrating polymer network (IPN) method. The structure and composition of the composite samples were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). The viscoelastic behaviors of the rubber composites and their vulcanizates were explored using a rubber processing analyzer (RPA) in the rheometer, strain sweep and temperature sweep modes. The storage and loss moduli of SBR increased significantly with the incorporation of different hybrid fillers, which was attributed to the formation of an interphase between the hybrid fillers and rubber matrix, and the effective dispersion of the hybrid fillers. The mechanical properties (hardness, tensile strength, oxygen transmission rate, and swelling rate) of the composite samples were characterized in detail. From the results of the mechanical test, it was found that BC-CS-PVA0SBR had the best mechanical properties. Therefore, the BC-CS-PVA hybrid filler provided the best reinforcement effects for the SBR latex in this research.

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1681-1691
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• 2023

Flavin mononucleotide-binding proteins or domains emit cyan-green fluorescence under aerobic and anaerobic conditions, but relatively low fluorescence and less thermostability limit their application as reporters. In this work, we incorporated the codon-optimized fluorescent protein from Chlamydomonas reinhardtii with two different linkers independently into the redox-responsive split intein construct, overexpressed the precursors in hyperoxic Escherichia coli SHuffle T7 strain, and cyclized the target proteins in vitro in the presence of the reducing agent. Compared with the purified linear protein, the cyclic protein with the short linker displayed enhanced fluorescence. In contrast, cyclized protein with incorporation of the long linker including the myc-tag and human rhinovirus 3C protease cleavable sequence emitted slightly increased fluorescence compared with the protein linearized with the protease cleavage. The cyclic protein with the short linker also exhibited increased thermal stability and exopeptidase resistance. Moreover, induction of the target proteins in an oxygen-deficient culture rendered fluorescent E. coli BL21 (DE3) cells brighter than those overexpressing the linear construct. Thus, the cyclic reporter can hopefully be used in certain thermophilic anaerobes.

• Journal of the Korean Ceramic Society
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• v.41 no.8
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• pp.623-627
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• 2004

Phase formation and electrical conduction behavior of Ba-doped LaBaGa $O_4$ layered perovskite were studied. Orthorhombic single phase of $K_2$Ni $F_4$-type structure was observed for the composition range of 0$\leq$x$\leq$0.2 in the La$\_$1＋x/Ba$\_$1＋x/Ga $O_4$$\_$4-$\delta$/ system by X-ray analysis. In the dry atmosphere, La$\_$0.8/Ba$\_$1.2/Ga$\_$3.9/ exhibited mixed conduction of oxygen ion and hole (p-type) at high p( $O_2$). However, in water vapor containing atmosphere, it showed proton conduction due to the incorporation of water into oxygen vacancies. As the temperature decreased, the contribution of proton conductivity to the total conduction increased and proton conduction was dominant below 350$^{\circ}C$. The activation energy for proton conduction was calculated as 0.72 eV.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.7
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• pp.8-16
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• 2010

In this paper, we investigated the effects of $O_2$ fraction on the properties of Al-doped ZnO (AZO) thin films prepared by radio frequency (RF) magnetron sputtering. Hall, photoluminescence (PL), and X-ray photoelectron spectroscopy (XPS) measurements revealed that the p-type conductivity was exhibited for AZO films with an $O_2$ fraction of 0.9 while the n-type conductivity was observed for films with $O_2$ fractions in range of 0 - 0.6. PL and XPS also showed that the acceptor-like defects, such as zinc vacancies and oxygen interstitials, increased in films prepared by an $O_2$ fraction of 0.9, resulting in the p-type conductivity in the films. Hall results indicated that AZO films prepared by $O_2$ fractions in range of 0 - 0.6 can be used for electrode layers in the applications of transparent thin film transistor. We concluded from the X-ray diffraction analysis that worse crystallinity with a smaller grain size as well as higher tensile stress was observed in the films prepared by a higher $O_2$ fraction, which is related to incorporation of more oxygen atoms into the films during deposition. The study of atomic force microscope suggested that the smoother surface morphology was observed in films prepared by using $O_2$ fraction, which causes the higher resistivity in those films, as evidenced by Hall measurements.

• Journal of the Korean Vacuum Society
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• v.19 no.1
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• pp.14-21
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• 2010

Ge is one of the attractive channel materials for the next generation high speed metal oxide semiconductor field effect transistors (MOSFETs) due to its higher carrier mobility than Si. But the absence of a chemically stable thermal oxide has been the main obstacle hindering the use of Ge channels in MOS devices. Especially, the fabrication of gate oxide on Ge with high quality interface is essential requirement. In this study, $HfO_xN_y$ thin films were prepared by plasma-enhanced atomic layer deposition on Ge substrate. The nitrogen was incorporated in situ during PE-ALD by using the mixture of nitrogen and oxygen plasma as a reactant. The effects of nitrogen to oxygen gas ratio were studied focusing on the improvements on the electrical and interface properties. When the nitrogen to oxygen gas flow ratio was 1, we obtained good quality with 10% EOT reduction. Additional analysis techniques including X-ray photoemission spectroscopy and high resolution transmission electron microscopy were used for chemical and microstructural analysis.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.12-23
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• 2020

Edible films containing antimicrobial agents can be used as safe alternatives to preserve food products. Essential oils are well-recognized antimicrobials. However, their low water solubility, volatility and high sensitivity to oxygen and light limit their application in food preservation. These limitations could be overcome by embedding these essential oils in complexed product matrices exploiting the encapsulation efficiency of β-cyclodextrin. This study focused on the maximization of β-cyclodextrin production using cyclodextrin glucanotransferase (CGTase) and the evaluation of its encapsulation efficacy to fabricate edible antimicrobial films. Response surface methodology (RSM) was used to optimize CGTase production by Brevibacillus brevis AMI-2 isolated from mangrove sediments. This enzyme was partially purified using a starch adsorption method and entrapped in calcium alginate. Cyclodextrin produced by the immobilized enzyme was then confirmed using high performance thin layer chromatography, and its encapsulation efficiency was investigated. The clove oil/β-cyclodextrin inclusion complexes were prepared using the coprecipitation method, and incorporated into chitosan films, and subjected to antimicrobial testing. Results revealed that β-cyclodextrin was produced as a major product of the enzymatic reaction. In addition, the incorporation of clove oil/β-cyclodextrin inclusion complexes significantly increased the antimicrobial activity of chitosan films against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella Typhimurium, Escherichia coli, and Candida albicans. In conclusion, B. brevis AMI-2 is a promising source for CGTase to synthesize β-cyclodextrin with considerable encapsulation efficiency. Further, the obtained results suggest that chitosan films containing clove oils encapsulated in β-cyclodextrin could serve as edible antimicrobial food-packaging materials to combat microbial contamination.

• Journal of Pharmaceutical Investigation
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• v.37 no.4
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• pp.243-247
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• 2007

Retinoids have many important and diverse functions and particularly, have been widely used as anti-aging agent and for the treatment of acne and psoriasis in cosmetics. However, retinoids have low stability against the air, light, water, oxygen and heat, thus, to stabilize the retinoids in formulations is very critical procedure. In this study, cubic liquid crystalline phase of monoolein was applied to stabilize the retinylpalmitate (RP) and to enhance the transdermal permeation. Cubic liquid crystalline phase significantly enhanced the stability of RP. After 15 days, the content of RP in the cubic formulation was 94.7% while the content of RP in ethanol solution was below 0.5% at room temperature. Although BHT containing crystalline phase showed the slightly increased stability of RP, there were no significant differences in RP stability between with or without antioxidants (ascorbic acid, ${\alpha}$-tocopherol, BHT, BHA) at $40^{\circ}C$. The skin retention of RP in crystalline formulations was approximately $5.3{\sim}6.4$ times greater than that of o/w cream formulation. Incorporation of RP into cubic liquid crystalline phase of monoolein effectively stabilized the RP and worked as excellent topical vehicle for RP. Liquid crystalline phase is considered to be suitable formulation for RP for topical delivery system as a stabilizer and permeation enhancing agent.