• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.554-564
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• 1996

Oxygen reduction in an alkaline fuel cell was studied by using perovskite of $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35, and 0.50) as an oxygen electrode catalyst. The changes in the catalytic properties as a function of Fe content were investigated by XRD, TG, and TPR. XRD patterns gave different lattice parameters of the catalysts. TG study revealed that Fe was so stabilized in the perovskite structure as to be hardly reduced even up to $900^{\circ}C$, and the amount of oxygen which was eliminated at high temperature increased with the fraction of Fe because Fe induced the increase of Co-O binding energy. From TPR study, ${\alpha}$-(low temperature peak) and ${\beta}$-(high temperature peak)states were observed. The bond strength of the ${\beta}$-species which was associated strongly with Co of the perovskite increased proportionally with the fraction of Fe. The ${\alpha}$-species, reversible oxygen, was the active species in the oxygen reduction. The ${\alpha}$-peak temperature which reflected the binding energy between Co and ${\alpha}$-state oxygen moved to lower temperature with the increase of lattice parameter of the catalytst due to the increase of Fe content. The decrease in the binding energy increased the activity in the oxygen reduction, but the decrease of ${\alpha}$-species with the increase of Fe content decreased the activity. The increase in the surface area with Fe content had little effect on the activity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.2
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• pp.117-127
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• 2008

In this study, the antioxidative effects, inhibitory effects on elastase, and components of Cayratia japonica extracts were investigated. The free radical(1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities($FSC_{50}$) of extract/fractions of Cayratia japonica were in the order: 50% ethanol extract(114.3 ${\mu}g/mL$)${\mu}g/mL$)${\mu}g/mL$). Reactive oxygen species(ROS) scavenging activities($OSC_{50}$) of some Cayratia japonica extracts in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activities were deglycosylated flavonoid aglycone fraction($OSC_{50},\;3.30{\mu}g/mL$)<50% ethanol extract(1.21 ${\mu}g/mL$)${\mu}g/mL$). Ethyl acetate fraction showed the most prominent scavenging activity. The protective effects of extract/fractions of Cayratia japonica on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Cayratia japonica extracts suppressed photohemolysis in a concentration dependent manner($1{\sim}25{\mu}g/mL$), particularly deglycosylated flavonoid aglycone fraction exhibited the most prominent celluar protective effect(${\tau}_{50}$, 175.05min at 25 ${\mu}g/mL$). Aglycone fractions obtained from the deglycosylation reaction of ethyl acetate fraction among the Cayratia japonica extracts, showed 2 bands in TLC and 2 peaks in HPLC experiments(360 nm). Two components were identified as luteolin(composition ratio, 47.50%), apigenin(52.50). TLC chromatogram of ethyl acetate fraction of Cayratia japonica extract revealed 3 bands and HPLC chromatogram showed 4 peaks, which were identified as luteolin-7-O-${\beta}$-D-glucopyranoside(composition ratio, 11.14%), apigenin-7-O-${\beta}$-D-glucuronopyranoside(15.38%), luteolin(23.55%) and apigenin(49.92%) in the order of elution time. The inhibitory effect of aglycone fraction on elastase($IC_{50},\;70.5{\mu}g/mL$) was very high. These results indicate that extract/fractions of Cayratia japonica can function as antioxidants in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Cayratia japonica extract and antioxidative effects could be applicable to new cosmetics.

• Journal of Photoscience
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• v.9 no.2
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• pp.37-40
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• 2002

Ascidians are lower chordates, and their tadpole-like larvae share a basic body plan with vertebrates. To study photoreceptive systems in ascidians, we have isolated and characterized cDNA clones for three opsins, five G protein ${\alpha}$ subunits (G${\alpha}$), catalytic and regulatory subunits of cGMP phosphodiesterase (PDE), and arrestin from the ascidian Ciona intestinalis tadpole larva. Ci-opsin1 and Ci-opsin2 are vertebrate-type opsins, while Ci-opsin3 is a retinal photoisomerase similar to retinochrome and mammalian RGR. Both Ci-opsin1 and arrestin are specifically localized in the photoreceptor cells of the ocellus, whereas Ci -opsin2 is not expressed in the photoreceptors, but is co-localized in another population of neurons in the brain with PDE (Ci-PDE9 and Ci-PDE$\delta$). Ci-opsin3 is present in the entire region of the brain. Though five different cDNAs encoding Ga have been cloned, no transducin-type G protein has been found yet. Interestingly, one of G${\alpha}$i isoform is conspicuously expressed in the entire region of the brain. The Ci-opsin3 gene expression was observed in a broad area of the brain vesicle as well as in the visceral ganglion. Genes encoding ascidian homologs of CRALBP and ${\beta}$-CD, whose function is required for the mammalian visual cycle, are co-expressed with Ci-opsin3 in the brain vesicle and visceral ganglion. Localization of Ci-opsin3, CRALBP, and ${\beta}$-CD in a broad area of the brain suggests that the brain of the ascidian larva has a visual cycle system similar to that of the vertebrate RPE. Based on these data, we discuss the evolution of vertebrate visual systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4619-4628
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• 2012

The purpose of this study was to investigate the relationship between alcohol use and drinking problems among college students. Data were collected by structured questionnaires from 400 college students by convenient sampling methods from September 26 to October 14, 2011. Data were analyzed by SPSS/WIN 15.0 program. The results were as follows: According to the Alcohol Use Disorder Identification Test (AUDIT), subjects were classified into four groups such as 40.2% of no problem, 36.7% of drinking problem, 6.8% of high risk drinking problem and 16.3% of alcohol dependence. The alcohol use and drinking problems were significant difference for gender, age, type of residence, age of first drinking, cause of drinking, frequency and amount of drinking. The alcohol use was correlated with drinking problems: social function impairment(r=.601, p<.01), behavior problem(r=.579, p<.01), family and interpersonal impairment(r=.637, p<.01). The influencing factors of drinking problems were alcohol use(${\beta}$=.640, p=.000). This study concludes that it is necessary to establish alcohol use policies on campus and develop temperance education program to reduce alcohol consumption and drinking problems.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.2
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• pp.231-239
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• 1999

The microstructure of ceramic composite has been found to be governed by the type and amount of the secondary phase, the sintering aid, and the sintering conditions such as sintering temperature, pressure and holing time. Moreover, tribological properties are strongly dependent on microsturcture of composite and operating conditions. In this study, silicon nitride with various amount of magnesia as a sintering aid were prepared and sintered by a hot pressing (HP) technique. Microstructure, mechanical properties (hardness, strength, and fracture toughness), and tribological properties in different environments of $Si_{3}N_{4}$ (in air, water, and paraffine oil) were investigated as a function of MgO content in $Si_{3}N_{4}$. As increasing the amount of MgO in $Si_{3}N_{4}$, the glassy phase in the grain boundaries enlarged the $\beta$-phase elongated grains, and also degraded the Hertzian contact damage resistance. Tribological behaviors in air was seemed to be determined by fracture toughness of $Si_{3}N_{4}$, and those in water and paraffin oil was seemed to be determined by hardness as well as strength. Since glassy grain-boundary phase (MgO) in $Si_{3}N_{4}$ expected to be reacted with water during sliding, such tribochemical reaction reduced wear. In paraffin oil under a higher applied load, the initial sliding dominated wear rate because of Hertzian contact damage.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.75-85
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• 1989

In opsonized zymosan activated PMN leukocytes, N-ethylamleiamide and $Hg^{++}$, penetrable sulfhydryl group inhibitors, inhibited superoxide generation, NADPH oxidase activity and lysosomal enzyme (lactic dehydrogenase and ${\beta}-glucuronidase$) secretion. P-Chloromercuribenzoic acid and p-chloromercuribenzenesulfonic acid, surface sulfhydryl group inhibitors did not affect superoxide generation but effectively inhibited both NADPH oxidase activity and lysosomal enzyme secretion. During phagocytosis, contents of surface and soluble sulfhydryl groups were gradually decreased with increasing incubation times. N-ethylmaleiamide and $Hg^{++}$ caused a loss of both surface and soluble sulfhydryl groups. P-Chloromercuribenzoic acid and p-chloromercuribenzenesulfonic acid significantly decreased the surface sulfhydryl content but did not after soluble sulfhydryl groups. Cysteine and mercaptopropionylglycine inhibited superoxide generation and lysosomal enzyme secretion. Glutathione had no effect on superoxide generation but remarkably inhibited lactic dehydrogenase release. Suppression of superoxide generation by N-ethylmaleiamide was reversed by cysteine and mercaptopropionyl-glycine but not by glutathione. Inactivation of NADPH oxidase by N-ethylmaleiamide was prevented by glutathione, cysteine or mercaptopropionylglycine. Stimulated superoxide generaion by carbachol was completely abolished by N-ethylrnaleiamide and antagonized by atropine. Thus, the expression of PMN leukocyte response to external stimuli may be associated with the change of sulfhydryl groups content. It is suggested that lysosomal enzyme secretion is influenced by both surface and soluble sulfhydryl groups, whereas superoxide generation by intracellular soluble sulfhydryl groups.

• Tuberculosis and Respiratory Diseases
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• v.44 no.4
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• pp.815-821
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• 1997

Background : Salmeterol, a new ${\beta}_2$-adrenergic receptor agonist, is a long-acting bronchodilator and benefits patients with asthma who have nocturnal symptoms. We wished to assess the efficacy of inhaled salmeterol ($50{\mu}g$ bid) compared to inhaled salbutamol ($200{\mu}g$ qid) for the treatment of bronchial asthma, particularly nocturnal asthma. Method : We randomly assigned 35 patients (25 female and 10 male patients, 15 to 50 years old) to one of two treatment groups : one group received $50{\mu}g$ of salmeterol twice daily and another did $200{\mu}g$ salbutamol four times per day. And this study was performed as an open-label and the 6 weeks inhalation period. Results : Analysis of symptam score ; Day and night time symptom score showed significant difference between salmeterol and salbutamol Group (p<0.05). Number of days for additional bronchodilator requirements; The number of days and puffs for additional bronchodilator were lower in the salmeterol group in either day and night time (p<0.05). Pulmonary function test ; $FEV_1$ showed significant increase in salmeterol group compared to salbutamol group after 2 and 4 weeks inhalation period. Adverse effects ; We found no evidence of tolerance to the bronchodilating effects of salmeterol, and adverse reactions to all the treatments were infrequent and mild. Conclusion : For the management of bronchial asthma, salmeterol given twice daily is superior to salbutamol given four times daily.

• Journal of Life Science
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• v.27 no.1
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• pp.1-7
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• 2017

Abnormal actin remodeling is a typical characteristic of tumor cells. Thymosin ${\beta}_{10}$ (TB10) and profilin-1 (PFN-1) are actin-binding proteins and essential regulators of actin polymerization. We previously showed that TB10 induced death in ovarian cancer cells by sequestering F-actin, but the underlying mechanisms of this induction have not been explored. In this study, we identified TB10 as a novel regulator of PFN-1 and demonstrated its novel function as a tumor suppressor in ovarian cancer cell lines. The present study investigated protein expression profiles through polyacrylamide gel electrophoresis (PAGE) and liquid chromatography-mass spectroscopy (LC-MS/MS) in SKOV3 cells, an ovarian cancer cell line, that were transiently transfected with TB10. PFN-1 was highly overexpressed in response to TB10, and overexpression of PFN-1 resulted in inhibition of cell proliferation and migration and promotion of cellular apoptosis in ovarian cancer cells. Furthermore, transiently transfected PFN-1 appeared to deactivate the Erk signaling pathway, followed by decreased expression of Elk-1 and Egr-1 in human ovarian cancer cells. Interestingly, PFN-1 did not affect the activation of Akt. The results demonstrated that PFN-1 induced apoptotic cell death and inhibited proliferation and migration in ovarian cancer cells, suggesting that PFN-1 may be valuable in anti-cancer therapy.

• Journal of Oriental Neuropsychiatry
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• v.3 no.1
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• pp.25-45
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• 1992

Many phychiatrists have reported that the change of serotonin concentration would cause mental disorder and affect the pathological conditions such as schizophrenia, depression and eating behabior. The end product of serotonin metabolism was excreted as 5-HIAA in urine. Serum lipids, according to the report, were concerned with obesity, said it was. This study aims to observe the changes of plasma serotonin, urinary 5-HIAA and serum lipids, making use of Fat Cell Mass rate of 27 normal persons and 42 psychosomatic patients. For this, I also observed the change of serotonin, 5-HIAA and lipids of the psychosomatic patients by the use of 3 kinds of herbs as treatment medication on the basis of physical symptoms and the results were obtained as follows; 1. Urinary 5-HIAA is correlated with the body water rate(r=0.381), while reversely correlated with the Fat Cell Mass rate(r=-0.330). 2. Compared the control group with the patients group for the serum lipids value, they showed the significant results ; $146.4{\pm}5.71$ mg/dl and $166.9{\pm}6.56$ mg/dl in the total cholestrol value over- weights, $471.2{\pm}42.99$ mg/dl in the total lipid value, and $158.1{\pm}6.50$ mg/dl and $181.1{\pm}6.30$ mg/dl in the phospholipid of the obesity, respectively. 3. With comparison of each group to other group to the others for Fat Cell Mass rate, the total cholesterol showed the significant differences when the Fat Cell Mass rate was 20% or more, HDL-cholesterol value when 30% or more, and triglyceride when 30% or more, respectively. 4. there was significant variations in the relations between Fat Cell Mass rate and body water, which body mass index was increased as the body water was decreased. 5. Fat Cell Mass rate was correlated with Cholesterol(r = 0.420), triglyceride (r = 0.443), and $\beta$-lipoprotein(r = 0.450) of serum lipids, while reversely correlated with HDL -Cholesterol(r = -0.354) and urinary 5- HIAA had the correlation coefficient of -0.330. 6. What related with body water rate urinary 5-HIAA (r = 0.381) and $\beta$-lipoprotein(r = -0.405). 7. there were significant changes in the total cholesterol value and HDL-Cholesterol Value of serum lipids after dose of Ondamtang, significant increase in the 5-HIAA value after dose of Samulansintang, and significant devrease in the Trigylceride value of serum lipids after dose of Shihosogansan. As a result, it was seen that there was direct correlations among the Fat Cell Mass, urinary 5-HIAA, and serum lipids and stress from the mental conditions was not correlated directly to Serotonin, 5-HIAA, and serum lipids. I would like to conclude, therefore, that the detailed study should be performed on the function of serotonin of hypothalamus.

• The Korean Journal of Applied Statistics
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• v.10 no.1
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• pp.69-84
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• 1997

We consider a linear calibration problem, $y_i = $$\alpha + \beta (x_i - x_0) + \epsilon_i$, $i=1, 2, {\cdot}{\cdot},n$ $y_f = \alpha + \beta (x_f - x_0) + \epsilon, $ where we observe $(x_i, y_i)$'s for the controlled calibration experiments and later we make inference about $x_f$ from a new observation $y_f$. The objective of the calibration design problem is to find the optimal design $x = (x_i, \cdots, x_n$ that gives the best estimates for $x_f$. We compare Kim(1989)'s Bayesian design which minimizes the expected value of the posterior variance of $x_f$ and some optimal designs from literature. Kim suggested the Bayesian optimal design based on the analysis of the characteristics of the expected loss function and numerical must be equal to the prior mean and that the sum of squares be as large as possible. The designs to be compared are (1) Buonaccorsi(1986)'s AV optimal design that minimizes the average asymptotic variance of the classical estimators, (2) D-optimal and A-optimal design for the linear regression model that optimize some functions of $M(x) = \sum x_i x_i'$, and (3) Hunter & Lamboy (1981)'s reference design from their paper. In order to compare the designs which are optimal in some sense, we consider two criteria. First, we compare them by the expected posterior variance criterion and secondly, we perform the Monte Carlo simulation to obtain the HPD intervals and compare the lengths of them. If the prior mean of $x_f$ is at the center of the finite design interval, then the Bayesian, AV optimal, D-optimal and A-optimal designs are indentical and they are equally weighted end-point design. However if the prior mean is not at the center, then they are not expected to be identical.In this case, we demonstrate that the almost Bayesian-optimal design was slightly better than the approximate AV optimal design. We also investigate the effects of the prior variance of the parameters and solution for the case when the number of experiments is odd.