• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.166-172
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• 2022

A method of efficiently purifying high value-added indole among components of coal tar absorption oil was studied using a step-by-step process of extraction-distillation-crystallization. The coal tar absorption oil used in this study contains 1.2% naphthalene, 0.1% quinoline, 0.4% isoquinoline, 6.4% indole, 21.0% 1-methylnaphthalene, 48.8% 2-methylnaphthalene, and 11.7% biphenyl as main components. For the separation and purification of indole, methanol was first used as a solvent to separate indole species in the coal tar absorption oil into an extract phase. And then methanol was recovered by distillation. Subsequently, an extraction solution where methanol was removed was mixed with normal hexane, and then crystallized to recover indole having a purity of 99.3%. Based on the experiments of this study, a purification process scheme for indole in coal tar absorption oil was proposed.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.23-27
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• 2023

Organic light-emitting diode(OLED) is very thin organic films which are hundreds of nanometers. Unlike bottom-emission OLED(BEOLED), top-emission OLED(TEOLED) emits light out the front, opaque moisture absorbents or metal foils can't be used to prevent moisture and oxygen. And it is difficult to have flexible characteristics with glass encapsulation, so thin film encapsulation which can compensate for those two disadvantages is mainly used. In this study, Al₂O₃ thin films by atomic layer deposition(ALD) were examined by changing the argon gas purge flow rate and we applied this Al₂O₃ thin films to the encapsulation of TEOLED. Ag / ITO / N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine / tris-(8-hydroxyquinoline) aluminum/ LiF / Mg:Ag (1:9) were used to fabricate OLED device. The characteristics such as brightness, current density, and power efficiency are compared. And it was confirmed that with a thickness of 40 nm Al₂O₃ thin film encapsulation process did not affect OLED properties. And it was enough to maintain a proper OLED operation for about 9 hours.

• Journal of Microbiology
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• v.41 no.3
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• pp.189-195
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• 2003

To enhance the reductive dechlorination of polychlorinated biphenyls (PCBs) under anaerobic conditions, we examined the adjunctive effects of cobalt (Co) and nickel (Ni), which are the central metals of transition-metal cofactors of coenzyme F$\_$430/ and vitamin B$\_$12/, respectively, on the dechlorination of Aroclor 1248. After 32 weeks of incubation, the average numbers of chlorines per biphenyl in culture vials supplemented with 0.2, 0.5, and 1.0 mM of Co reduced from 3.88 to 3.39, 2.92, and 3.28, respectively. However, the numbers of chlorine after supplementing with Ni decreased from 3.88 to 3.43, regardless of the Ni concentrations. The observed congener distribution patterns of all vials with different conditions were similar to the pattern produced by the dechlorination process of H' after 21 weeks of incubation, and these patterns were unchanged up to week 32, except for vials supplemented with 0.5 and 1.0 mM of Co. In vials containing 0.5 mM of Co, meta-rich congeners, such as 25/ 25-,24/25-, and 25/23-chlorobiphenyls (CBPs), which were found as accumulated products of dechlorination in other conditions, were further dechlorinated, and 25/2-, 24/2-, and 2/2-CBPs were concomitantly increased after 32 weeks of incubation. In this case, the congener distribution was similar to the dechlorination pattern of process M. From these results, we suggested that the enrichment of cultures with Co might stimulate the growth of specific populations of meta-dechlorinators, and that populations might promote a change in the dechlorination process from H' to M, which is known to be less effective on the dechlorination of the more highly chlorinated congeners of PCBs.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.56-70
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• 1998

This study was carried out to investigate the structural characteristics of kraft lignin and the wood degrading characteristics, the productivity of ligninolytic enzymes and the enzymatic degradation of kraft lignin by white-rot fungi. To purify kraft lignin, precipitation of kraft pulping black liquors of pitch pine meal was done by titration with lN $H_{2}SO_{4}$ reaching to pH 2, and isolation of the precipitates done by centrifugation. The isolated precipitates from pitch pine were redissloved in lN NaOH, reprecipitated by titration with lN $H_{2}SO_{4}$, washed with deionized water, and kept ofr analysis after freeze drying. Fractionation of the precipitates in solution by successive extraction with $CH_{2}Cl_{2}$ and MeOH, and the fractionates were named SwKL, SwKL I, SwKL II, and SwKL III for pitch pine kraft lignin. The more molecular weights of kraft lignin increased, the less phenolic hydroxyl groups and the more aliphatic hydroxyl groups. Because as the molecular weights increased, the ratio of etherified guaiayl/syringyl(G/S ratio) and the percentage were increased. The spectra obtained by 13C NMR and FTIR assigned by comparing the chemical shifts of various signals with shifts of signals from autherized ones reported. The optimal growth temperature and pH of white-rot fungi in medium were $28^{\circ}C$ and 4.5-5.0, respectively. Especially, in temperature and pH range, and mycelial growth, the best white-rot fungus selected was Phanerochaete chrysosporium for biodegradation. For the degradation pathways, the ligninolytic fungus jcultivated with stationary culture using medium of 1% kraft lignin as a substrate for 3 weeks at $28^{\circ}C$. The weight loss of pitch pine kraft lignin was 15.8%. The degraded products extracted successively methoanol, 90% dioxane and diethyl ether. The ether solubles were analyzed by HPLC. Kraft lignin degradation was initiated in $\beta$-O-4 bonds of lignin by the laccase from Phanerochaete chrysosporium and the degraded compounds were produced from the cleavage of $C\alpha$-$C\beta$ linkages at the side chains by oxidation process. After $C\alpha$-$C\beta$ cleavage, $C\alpha$-Carbon was oxidized and changed into aldehyde and acidic compounds such as syringic acid, syringic aldehyde and vanilline. And the other compound as quinonemethide, coumarin, was analyzed. The structural characteristics of kraft lignin were composed of guaiacyl group substituted functional OHs, methoxyl, and carbonyl at C-3, -4, and -5 and these groups were combinated with $\alpha$ aryl ether, $\beta$ aryl ether and biphenyl. Kraft lignin degradation pathways by Phanerochaete chrysosporium were initially accomplished cleavage of $C\alpha$-$C\beta$ linkages and $C\alpha$ oxidation at the propyl side chains and finally cleavage of aromatic ring and oxidation of OHs.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1807-1818
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• 2005

New PPV based conjugated polymers, containing terphenyl units, were prepared as the electroluminescent (EL) layer in light-emitting diodes (LEDs). The prepared polymers, poly[2,5-bis(4-(2-etylhexyloxy)phenyl)-1,4-phenylenevinylene] (BEHP-PPV), poly[2-(2-ethylhexyloxy)-5-(4-(4-(2-etylhexyloxy)phenyl)phenyl)-1,4-phenylenevinylene] (EEPP-PPV) and poly[2-(2-ethylhexyloxy)-5-(9,9-bis(2-etylhexyl)fluorenyl)-1,4 phenylenevinylene] (EHF-PPV), were soluble in common organic solvents and used as the EL layer in double layer light-emitting diodes (LEDs) (ITO/PEDOT/polymer/Al). The polymers were prepared by the Gilch reaction. The number-average molecular weight $(M_n)$, weight-average molecular weight $(M_w)$, and the polydispersities (PDI) of these polymers were in the range of 9000-58000, 27000-231000, 2.9-3.9, respectively. These polymers have quite good thermal stability with decomposition starting above 320-350. The polymers show photoluminescence (PL) with maximum peaks at around 526-562 nm (exciting wavelength, 410 nm) and blue EL with maximum peaks at around $\lambda_{max}$ = 526-552 nm. The current-voltageluminance (I-V-L) characteristics of polymers show turn-on voltages of 5 V. Even though both of EEPP-PPV and BEHP-PPV have the same terphenyl group in the repeating unit, EEPP-PPV with directly substituted alkoxy group in the back bone has longer effective conjugation length than BEHP-PPV, and exhibits red shift in the PL spectra. Both of EEPP-PPV and EHF-PPV have ter-phenyl units and directly substituted alkoxy group in back bone. EHF-PPV with fluorenyl unit attached to the PPV backbone has shorter effective conjugation length than EEPP-PPV with biphenyl unit, and exhibits blue shift in the PL spectra.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.234-238
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• 2015

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction was compared by the methanol and formamide extraction. The model coal tar fraction comprising four kinds of NHC (NHCs : quinoline, iso-quinoline, indole, quinaldine) and three kinds of bicyclic aromatic compound (BACs : 1-methylnaphthalene, 2-methylnaphthalene, dimethylnaphthalene), biphenyl and phenyl ether was used as a raw material. The aqueous solution of methanol and formamide were used as solvents. A batch-stirred tank was used as the raw material - a solvent contact unit of this work. Independent of the solvent used, the distribution coefficient of NHCs sharply increased by decreasing the initial volume ratio of water to the solvent and increasing the equilibrium operation temperature, whereas, the selectivity of NHCs in reference to BACs decreased. Decreasing the initial volume ratio of solvent to feed resulted in deteriorating distribution coefficients, but the selectivity of NHCs in reference to BAC was almost the constant. The distribution coefficient of NHCs by the methanol extraction was 3~5 times higher than that of NHCs by the formamide extraction, inversely, the selectivity of NHCs based on BACs by the formamide extraction was 3~7 times higher than that of NHCs by the methanol extraction. Furthermore, two different solvent extraction methods by adding the extraction processing speed to the balance between solvency and selectivity of NHCs were compared.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.272-281
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• 1995

The residual Polychlorinated biphenyls(PCBs) in the sediment of the Kumho River basin were measured because the Nakdong River was considered to be affected by the environmental quality of Kumho River. PCBs in the sediment were chlorinated and converted into Decachlorinated biphenyl(DCB) which showed the single peak in the GC-ECD chromatogram. The detectable concentrations of PCBs was 0.5ng/g in the sediment. PCBs in the 21 sediment samples was of Kumho River located at 7.5km from conjunction of Nakdong River were not detected from 100 samples. 49% of samples was showed lower than 50ng/g, and 9% did more than 400ng/g. The mean of PCBs concentrations was 131ng/g. The means of COD and organic carbon were 14.5mg/g and 3.41%, respectively. The relationship between PCBs were concentration and the distance from conjunction with Nakdong River was not significant. The concentration of PCBs were varied with the depth of the sediment down to the 250cm depth. The concentrations of PCBs in the depth 0-20cm and 50-90cm were higher than the mean concentration of PCBs. Along the cross of the stream, the concentrations of PCBs were 142ng/g at the center and 126 and 131ng/g at the river sides.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.4
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• pp.679-686
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• 1997

In order to investigate the distribution characteristics of polychlorinated Biphenyls (PCBs) at the southern of Korean East Sea, vertical measurements of temperature, salinity, DO and PCBs were performed by each depth of 5 stations during August - October 1996. Thermocline and salinocline were generally existed at depth of 30 m and water mass current of midwater in the southern of Korean East Sea was distributed below 30 m depth. The distribution of surface water mass in this area was extended to Tsusima area from the southern offshore of the Korean last Sea. In August 1996, concentration range of PCBs had $0.22\~0.36\;ng/\ell$ at surface layer and their concentrations at near Tsusima offshore were relatively decreased. Total mean concentration of PCBs was $0.29\;ng/\ell$ in the sea surface and $0.31\;ng/\ell$ in the middle layer. PCBs seemed to correlate well with suspended particles. And vortical and horizontal distribution of their concentrations showed comparatively uniform pattern. Relatively high compositional ratio of Di- and Tri-PCBs could be found at the sea surface, while compositional ratio of Penta-PCBs dominates over other congener at deep layer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6633-6638
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• 2014

The Pharmacological potential, such as antioxidant, anti-inflammatory, and antibacterial activities of Portulaca oleracea (PO) and Petroselinum sativum (PS) extracts are well known. However, the preventive properties against hepatocellular carcinoma cells have not been explored so far. Therefore, the present investigation was designed to study the anticancer activity of seed extracts of PO and PS on the human hepatocellular carcinoma cells (HepG2). The HepG2 cells were exposed with $5-500{\mu}g/ml$ of PO and PS for 24 h. After the exposure, cell viability by 3-(4,5-dimethylthiazol-2yl)-2,5-biphenyl tetrazolium bromide (MTT) assay, neutral red uptake (NRU) assay, and cellular morphology by phase contrast inverted microscope were studied. The results showed that PO and PS extracts significantly reduced the cell viability of HepG2 in a concentration dependent manner. The cell viability was recorded to be 67%, 31%, 21%, and 17% at 50, 100, 250, and $500{\mu}g/ml$ of PO, respectively by MTT assay and 91%, 62%, 27%, and 18% at 50, 100, 250, and $500{\mu}g/ml$ of PO, respectively by NRU assay. PS exposed HepG2 cells with $100{\mu}g/ml$ and higher concentrations were also found to be cytotoxic. The decrease in the cell viability at 100, 250, and $500{\mu}g/ml$ of PS was recorded as 70%, 33%, and 15% by MTT assay and 63%, 29%, and 17%, respectively by NRU assay. Results also showed that PO and PS exposed cells reduced the normal morphology and adhesion capacity of HepG2 cells. HepG2 cells exposed with $50{\mu}g/ml$ and higher concentrations of PO and PS lost their typical morphology, become smaller in size, and appeared in rounded bodies. Our results demonstrated preliminary screening of anticancer activity of Portulaca oleracea and Petroselinum sativum extracts against HepG2 cells, which can be further used for the development of a potential therapeutic anticancer agent.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.2 no.2
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• pp.118-122
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• 2016

Integrin ${\alpha}_v{\beta}_3$ plays an important role in the tumor metastases and angiogenesis. Arginine-glycine-aspartate (RGD) peptide motif binds to the integrin ${\alpha}_v{\beta}_3$. General $^{68}Ga$-labeled cyclic RGD peptides was rapidly eliminated from the circulatory system by renal excretion because of its hydrophilic property. The purpose of this study was to develop a novel $^{68}Ga$-labeled cyclic RGD peptides, which could acquire enhanced PET tumor images with improved pharmacokinetics by adopting biphenyl group between chelator and RGD peptides. $^{68}Ga$-DOTA-2P-c(RGDyK) was demonstrated a 12% higher lipophilicity level than $^{68}Ga$-DOTA-c(RGDyK) as a reference compound. In the animal PET, $^{68}Ga$-DOTA-2P-c(RGDyK) represented relatively lower blood-clearance, and an increased signal to noise ratio compared to $^{68}Ga$-DOTA-c(RGDyK). From these perspective, $^{68}Ga$-DOTA-2P-c(RGDyK) could be a good candidate for in integrin ${\alpha}_v{\beta}_3$-expressed tumor imaging.