• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.674-678
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• 2020

In this study, a Pd/TiO2 catalyst which oxidized H2 at room temperature without an additional energy source was prepared. And a specific surface area of TiO2 as a support was not proportional to H2 oxidation reaction performance of Pd/TiO2 catalyst. In addition La2O3 was added to Pd/TiO2 catalyst in order to evaluate the performance effect due to the change of catalysts physical properties. A Pd/La2O3-TiO2 was prepared by adding different amounts of La2O3 to TiO2 and CO chemisorption analysis was performed. Compared to the conversion rate (14% at 0.5% H2) of the Pd/TiO2(G) catalyst, the Pd/La2O3-TiO2 catalyst showed 74% which was improved by more than five times. It was found that the larger the metal dispersion of Pd as an active metal is, the more favorable to H2 oxidation reaction is. However, when the added La2O3 amount exceeded 10%, the catalyst performance decreased again. Finally, it was concluded that the physical properties of the Pd/La2O3-TiO2 catalyst have a dominant influence on the catalytic activity until 0.3~0.5% of injected H2 concentrations and the catalyst reaction rate was controlled by substance transfer from 1% or more concentrations of H2.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.6
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• pp.389-395
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• 2011

Repeated administration of psychostimulants such as cocaine leads to the development of behavioral sensitization. Extracellular signal-Regulated Kinase (ERK), an enzyme important for long-term neuronal plasticity, has been implicated in such effects of these drugs. Although the nucleus accumbens (NAcc) is the site mediating the expression of behavioral sensitization by drugs of abuse, the precise role of ERK activation in this site has not been determined. In this study we demonstrate that blockade of ERK phosphorylation in the NAcc by a single bilateral microinjections of PD98059 (0.5 or $2.0{\mu}g/side$), or U0126 (0.1 or $1.0{\mu}g/side$), into this site dose-dependently inhibited the expression of cocaine-induced behavioral sensitization when measured at day 7 following 6 consecutive daily cocaine injections (15 mg/kg, i.p.). Acute microinjection of either vehicle or PD98059 alone produced no different locomotor activity compared to saline control. Further, microinjection of PD98059 ($2.0{\mu}g/side$) in the NAcc specifically lowered cocaine-induced increase of ERK phosphorylation levels in this site, while unaffecting p-38 protein levels. These results indicate that ERK activation in the NAcc is necessary for the expression of cocaine-induced behavioral sensitization, and further suggest that repeated cocaine evokes neuronal plasticity involving ERK pathway in this site leading to long-lasting behavioral changes.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.359-366
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• 2021

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive disorder and is the most common enzyme deficiency worldwide. Although this disease is rare in Korea, its prevalence may increase due to an increase of multicultural families. Patients with this deficiency are prone to hemolytic anemia provoked by specific drugs commonly used or prescribed in pediatric dentistry. It is necessary for pediatric dentists to have accurate knowledge of a patient's medical history and to consult with a pediatric hematologist to avoid oxidative stress that can lead to hemolysis. The most effective treatment is prevention of exposure to factors that may trigger anemia. Appropriate education regarding risk factors is essential for patients diagnosed with this disease. This case report aimed to discuss the drugs and dental management methods that should be cautious in children with G6PD deficiency.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.1-6
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• 1998

Our studies diagnose insulation degradation using the method of PD system. In analysis method of degradation, we make use of degradation information that analyzed the phase angle - PD pulse amplitude - degradation time( $\Phi$- PDA - t) pattern and phase angle- PD pulse number - degradation time( $\Phi$- PDN - t) pattern using statistical operators such as skewness(S), kurtosis(K). Secondly using statically operator such as the center of gravity (G), the gradient of the discharge distribution(C), we have analyzed for the prediction of life which we can be obtained the time, occurred of many pulse of small discharge amplitude.

• Korean Journal of Materials Research
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• v.19 no.4
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• pp.192-197
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• 2009

Carbon nanotubes (CNT) were used as a catalyst support where catalytically active Pd and Pt metal particles decorated the outside of the external CNT walls. In this study, Pd and Pt nanoparticles supported on $HNO_3$-treated CNT were prepared by microwave-assisted heating of the polyol process using $PdCl_2$ and $H_2PtCl_6{\codt}6H_2O$ precursors, respectively, and were then characterized by SEM, TEM, and Raman. Raman spectroscopy showed that the acid treated CNT had a higher intensity ratio of $I_D/I_G$ compared to that of non-treated CNT, indicating the formation of defects or functional groups on CNT after chemical oxidation. Microwave irradiation for total two minutes resulted in the formation of Pd and Pt nanoparticles on the acid treated CNT. The sizes of Pd and Pt nanoparticles were found to be less than 10 nm and 3 nm, respectively. Furthermore, the $SnO_2$ films doped with CNT decorated by Pd and Pt nanoparticles were prepared, and then the $NO_2$ gas response of these sensor films was evaluated under $1{\sim}5\;ppm$ $NO_2$ concentration at $200^{\circ}C$. It was found that the sensing property of the $SnO_2$ film sensor on $NO_2$ gas was greatly improved by the addition of CNT-supported Pd and Pt nanoparticles.

• Analytical Science and Technology
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• v.5 no.4
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• pp.349-358
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• 1992

The direct determination of lead in the whole-blood by graphite furnace atomic absorption spectrometric analysis was carried out by using the sample which was diluted five-fold with 1% Triton X-100. Matrix modification was tried to remove the interferences of blood matrix and also to get the optimum analytical condition. Good agreement with certificated values in reference materials(bovine blood) supplied by comparison program in Japan was obstained when 1% $(NH_4)_2HPO_4$ as matrix modifier and ashing temperature, $700^{\circ}C$ were used or 1% $(NH_4)_2HPO_4$ and 0.1% $PdCl_2$ as matrix modifier and ashed at $700^{\circ}C$. Standard deviations were appeared as 2.2~6.3% for 1% $(NH_4)_2HPO_4$ and 3.1~9.1% for 1% $(NH_4)_2HPO_4$ and 0.1% $PdCl_2$ in the range of $31{\sim}624{\mu}gPb/l$.

• Applied Chemistry for Engineering
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• v.10 no.8
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• pp.1210-1215
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• 1999

Optimum conditions of the hydrogenation of PNA to pure PPD were determined in a three-phase slurry reactor with suspended Pd/C catalyst particles. Minimization of mass transfer resistances at the interfaces of both gas-liquid and liquid-catalyst particles and control of overall reaction rate on catalyst surface leaded to decrease the hydrogen starvation on reaction active sites and to reduce the side reactions during hydrogenation. The optimum temperature, pressure, and catalysst concentration were confirmed to be in the range of $60^{\circ}C$, 60~70 psig, and 1~2 g-cat/L, respectively. Reaction rate was zero order with respect to the concentration of PNA and 1st order with respect to the pressure of hydrogen(P). Overall rate expression of the reaction was $R_A=6.44{\times}10^6{\cdot}H{\cdot}P{\cdot}m{\cdot}$exp(-4659/T) where H is constant, m is concentration of catalyst, and T is temperature.

• Nutritional Sciences
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• v.9 no.2
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• pp.61-67
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• 2006

Green tea has attracted attention with respect to its potential for preventing and treating neurodegenerative disease. The neurotoxin, 6-hydroxydopamine (6-OHDA), was used to produce experimental Parkinson's disease (PD) model. The purpose of this study was to investigate the effects of green tea diet on behavioral changes, striatal dopamine content, and hepatic antioxidant parameters of PD model rats. In this study, we used male Sprague-Dawley rats weighing $200\sim220g$ and injected 6-OHDA into the right substantia nigra and medial forebrain bundle of the brain. The supply of green tea diet was started at 2 weeks before 6-OHDA lesion and continually supplied during 0, 2, and 4 weeks after 6-OHDA lesion (GT-0, GT-2, GT-4). Behavioral disturbance was measured by the stepping and d-amphetamine drug-induced rotation tests. Then, we assayed the striatal dopamine content and the hepatic malondialdehyde (MDA), hydrogen peroxide $(H_2O_2)$, and superoxide dismutase (SOD) activity. The percentage of lesioned forepaw to non-lesioned forepaw step scores was the highest in GT-4 group among all groups at both 3 and 4 weeks after 6-OHDA lesion. At 4 weeks after 6-OHDA lesion, the rotation score was the lowest in GT-2 group (p<0.05). However, increasing rate of the rotation score from 2 to 4 weeks after 6-OHDA lesion was the lowest in GT-4 group. The striatal dopamine content was not significantly different among four groups by green tea diet. The hepatic MDA level was the lowest in GT-4 group among four groups. The hepatic SOD activity was increased with the prolongation of green tea diet period These results suggest that green tea diet affects behavioral changes in rats of PD model. It seems that continuous green tea supplementation has an influence on the reduction of behavioral disturbance and the hepatic MDA level. Accordingly, continuous green tea supplementation was recommended for the prevention and treatment of PD. However, further studies are needed to investigate the mechanisms and efficacy of green tea in PD.

• Korean Journal of Microbiology
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• v.41 no.4
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• pp.262-268
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• 2005

Intoxication of murine macrophages (RAW 264.7) with the anthrax lethal toxin (LeTx 100 ng/ml) results in profound alterations in the host cell gene expression. The role of LeTx in mediating these effects is unknown, largely due to the difficulty in identifying and assigning function to individual proteins. In this study, we have used two-dimensional polyacrylamide gel electrophoresis to analyze the protein profile of murine macrophages treated with the LeTx, and have coupled this to protein identification using MALDI-TOF mass spectrometry. Interpretation of the peptide mass fingerprint data has relied primarily on the ProFound database. Among the differentially expressed spots, cleaved mitogen-activated protein kinase kinase (Mek1) and glucose-6-phosphate dehydrogenase were increased in the LeTx treated macrophages. Mek1 acts as a negative element in the signal transduction pathway, and G6PD plays the role for the protection of the cells from the hyper-production of active oxygen. Our results suggest that this proteomic approach is a useful tool to study protein expression in intoxicated macrophages and will contribute to the identification of a putative substrate for LeTx.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.190-193
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• 2000

ab initio calculations are presented for M-Rg and M-Rg2 (M=Li, Na, Rg=He, Ar) van der Waals clusters.InternucIear distances and binding energies of LiHe, LiAr and NaAr obtained by all-electron MP2(6-311++G(3df,3pd)) method are in good agreement with experimental values. Calculated properties of LiHe$_2$, LiAr$_2$, NaHe$_2$ and NaAr$_2$ are also reported.