• Journal of Environmental Science International
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• v.11 no.1
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• pp.85-91
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• 2002

The effects of initial concentration of dissolved oxygen content, Cu(II) and EDTA in an aqueous Cu(II)-EDTA solution on $TiO_2$ photo-oxidation of EDTA were investigated using $TiO_2$ (Degussa P-25) and UV irradiation at $20{\circ}C$. In the presence of dissolved oxygen and/or Cu(II) the photo-oxidation rates of EDTA were enhanced. The rates linearly increased in the range of initial Cu(II) concentration below 1.79 mM, while abode this concentration those were kept constant. The trend or the EDTA photo-oxidation rates appeared to be akin to the Langmuir-Hinshelwood equation farm and the k values calculated were 0.05 mM/min for the free-EDTA system, and 0.17 mM/min far the Cu(II)-EDTA system. These meant the aqueous EDTA decomposition was enhanced due to weakening of the intra-molecular bond strength of EDTA by complexation with Cu(II) added. It was concluded the decomposition of aqueous EDTA by $TiO_2$ photo-oxidation was maximum in the presence of dissolved oxygen supplied by air purging and of Cu(II) with its concentration for 1:1 Cu(II)-EDTA complexation ratio.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.291-296
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• 1997

The studies were carried out to evaluate the constituents in the aerial part of Isodon excisus var. coreanus (Labiatae). From the aqueous fraction of methanol extract, compound I (${\alpha}$-[[3-(3, 4-dihydroxyphenyl)-1-oxo-2-propenyl]oxy]-3,4-dihydroxy-benzenepropanoic acid), compound II (9-methyl-dihydroferulic acid-4-O-.betha.-D-glucopyranosyl $(1{\rightarrow}2)$-${\alpha}$-L- rhamnopyranosyl (1.rarw.4)-.betha.-D-glucopyranoside), compound III (ent-7.alpha., 11${\alpha}$,15.betha.-trihydroxy-kaur-16-en-1-O-.betha.-D-glucopyranoside) and compound IV ($2{\alpha}$,3${\beta}$,$7{\alpha}$,23-tetrahydroxy-olean-12 -en-28-oic acid 28-O-${\beta}$-D-glucopyranoside) were isolated and identified on the basis of their physicochemical and spectroscopic evidences[IR, FAB(-)MS,$^{1}H-NMR,$$^{13}C-NMR,$$ HMQC$$^{1}H-^{1}H $COSY and HMBC (Heteronuclear Multiple Bond Connectivity)]. Especially, New compounds II and III were named Isodonin A and Isodonin B respectively.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.73-82
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• 1989

We developed a photo-CVD equipment for the deposition of silicon based insulating materials. Silicon dioxide thin films were deposited at various process conditions especially low temperature range $50-250^{\circ}C$. Low pressure mercury lamp was used in the direct excitation of $SiH_4/N_2O$ mixture gas without mercury sensitization. AES and ESCA analysis showed that oxygen to silicon atomic ratio and binding state of Si-O bond was nearly 2.0 and $SiO_2$ type, respectively. The refractive indices were measured to be 1.39-1.44, indicating that films were in relatively low density.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.4
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• pp.579-589
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• 2007

The objective of this study was to compare the shear bond strengths of five adhesive systems to the enamel and dentin of primary and permanent teeth. Fifty noncarious primary and fifty permanent teeth were collected and stored in an 0.1% thymol solution at room temperature after extraction. The tested adhesives were: Adper Scotchbond Multi-purpose Plus Adhesive (SM) Adper Single bond 2 (SB), Clearfil SE Bond (SE), Adper Prompt L-Pop (PL), GBond (GB). For the shear bonding test, the labial and lingual surfaces of primary and permanent teeth were used. To obtain a flat surface, the labial and lingual surfaces of the teeth were sanded on $SiO_2$ with number 600 grit and then divided into 20 groups of 10 surfaces each. All samples were theromocycled in water $5^{\circ}C$ and $55^{\circ}C$ for 1000 cycles. The results were as follows: 1. For primary enamel, shear bond strengths of SM and SB were significantly higher than that of SE and also SM, SB, and PL were higher than GB(p<0.05). 2. For primary dentin, there were no significant differences among the shear bond strengths of any other bonding systems except difference between SE and GB. 3. For permanent enamel, SB showed significantly higher mean shear bond strength than those of any other bonding systems(p<0.05). 4. For permanent dentin, SM showed significantly higher mean shear bond strength than that of PL and GB(p<0.05). 5. Between the primary enamel and dentin, there were significant differences in SM, SB, and GB, whereas there was statistically significant difference in PL between the permanent enamel and dentin(p<0.05). 6. Between the primary and permanent teeth on enamel, there were no significant differences among all bonding systems, whereas there were statistically significant differences in SM and SB between the primary and permanent teeth on dentin(p<0.05).

• Journal of Life Science
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• v.20 no.6
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• pp.853-860
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• 2010

The DevSR two-component system is a major regulatory system involved in redox sensing in Mycobacterium smegmatis. The DevSR system consists of the DevS histidine kinase and its cognate DevR response regulator. When exposed to hypoxic conditions, the DevS histidine kinase is activated to phosphorylate the DevR response regulator, leading to the transcriptional activation of the DevR regulation. The ligand-binding state of the heme embedded in the N-terminal GAF domain of DevS determines the kinase activity of DevS. In this study, we demonstrated that the redox-responsive cysteine (C547) in the C-terminal kinase domain is involved in the redox-dependent control of DevS kinase activity. The formation of an intersubunit disulfide bond between the C547 residues in the presence of $O_2$ led to inactivation of DevS kinase activity. The reduction of the oxidized DevS with reductants such as $\beta$-mercaptoethanol and dithiothreitol resulted in the restoration of DevS kinase activity. It was demonstrated in vivo by complementation test that the substitution of C547 to alanine partially impaired the sensory function of DevS in M. smegmatis.

• Nuclear Engineering and Technology
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• v.9 no.1
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• pp.39-44
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• 1977

The configuratior and conformation of N-methyl-C-phenylalkyl-ketimine isomers, Ph-CR=N$CH_3$ (R=H, $CH_3$, $CH_3$CH$_2$), have been studied from extended Huckel molecular orbital calculations. The result shows that the E-configuration of the C=N double bond is favored compared with that of the Z-configuration. The most preferable conformation of the phenyl ring rotamer in N-methyl-C-phenylaldimine and N-methyl-C-phenylmethylketimine are the coplanar forms with regard to the C=N plane, but the conformation of the $CH_3$CH$_2$-rotamer, in N-methyl-C-phenylethyl-ketimine, the gauche form (dihedral angle between C=N and $CH_3$CH$_2$- plane=90$^{\circ}$) is favored.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.671-674
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• 2001

Cyclodextrin glucanotransferase(CGTase) derived from recombinant Bacillus subtilis was partial purified and concentrated by ultrafiltration. The prepared CGTase were immobilized on various matrices by ionic interaction or covalent bond. CGTase covalently bound on CNBr-activated sepharose 4B were identified to be the highest immobilization activity among various immobilization methods. The optimum conditions for CGTase immobilization were determined; $30^{\circ}C$, 6Orpm, using O.2g CNBr-activated sepharose 4B in pH 6.0 phosphate buffer and 9hr immobilization.

• Journal of the Korean Ceramic Society
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• v.43 no.6 s.289
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• pp.327-332
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• 2006

The effect of the processing parameters on the sintered density and strength of silica-bonded SiC (SBSC) ceramics was investigated for three types of batches with different particle sizes. The SBSC ceramics were fabricated by an oxidation-bonding process. The process involves the sintering of powder compacts in air so that the SiC particles bond to each other by oxidation-derived $SiO_2$ glass or cristobalite. A finding of this study was that a higher flexural strength was obtained when the starting powder was smaller. When a ${\sim}0.3_{-{\mu}m}$ SiC powder was used as a starting powder, a high strength of $257{\pm}42\;MPa$ was achieved at a relative density of ${\sim}80%$.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1084-1088
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• 1994

Electrical characteristics of Fe-substituted sodalites were analyzed and equivalent circuits of samples were designed using impedance and admittance data. Internal components of resistances (R$_e$, R$_b$, and R$_{gb}$) and capacitances (C$_b$, C$_dl$ and C$_D$) could be extracted by changing the frequency of measurement at three different temperatures. Upon increasing the temperature, electrical properties of the samples could be elucidated in detail by equivalent circuit. The substitution of Fe on Al site was indirectly confirmed by ESCA and the results explain the lower polarity in Na-O bond of Fe 10 mole ${\%}$-substituted sodalite.

• Bulletin of the Korean Chemical Society
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• v.19 no.11
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• pp.1211-1216
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• 1998

Bis(diethyldithiocarbamato)ioxomolybdenum(VI), cis-MoO2(S2CNEt2)2, 1, reacted with chlorotrimethylsilane (Me33SiCl) to give a seven-coordinate, pentagonal bipyramidal complex MoOC12(S2CN]Et2)2, 3, in which the oxo ligand is trans to the chloride ligand and the two chloride ligands are mutually cis. The monooxo molybdenum complex bis(diethyidithiocarbamato)oxomolybdenum(IV), MoO(S2CNEt2)2, 2, reacted with phenyl isocyanate (PhNCO) to give an Mo dimer MO2{μ-N(CONPh)Ph}(μ-NPh)(NPh)2(S2CNEt2)2, 4, which contains an Mo-Mo bond, two diethyldithiocarbamato ligands, two terminal imido (NPh) ligands, and two bridging hnido (NPh) ligands. One of the two bridging NPh ligands seemed to have been attacked by the electrophilic phenyl isocyanate carbon, which suggests that the bridging imido NPh ligand is more nucleophilic than the terminal one. Crystallographic data for 3: monoclinic space group P21/c, a=8.908(l) Å, b=17.509(3) Å, c=12.683(2) Å, β=110.15(1)°, Z=4, R(wR2)=0.0611(0.1385). Crystallographic data for 4-THF: orthorhombic space group P212121, a=17.932(4) Å, b=22.715(5) Å, c=11.802(3) Å, Z=4, R(wR2)=0.0585(0.1286).