• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.2
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• pp.107-116
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• 2017

When drilling operation is being performed, many physical and chemical changes are occurred near wellbore. To handle various changes of well condition and keep drilling process safe, additives of bulk, such as bentonite for increasing density of drilling mud, barite for increasing viscosity of drilling mud, polymer for chemical control, or surfactant, are added into drilling mud through a mud shear mixer. Because the achievement of the required material property through mud mixing system is essential to stabilize drilling system, it is of importance to analyze multi-phase flow during mud mixing process, which is directly related to increase mixing performance of the system and guarantee the safety of the whole drilling system. In this study, a series of liquid-solid flow simulation based on a computational fluid dynamics (CFD) are performed with comparing to solid concentration in experiment by Gilles et al. [2004] to understand the characteristics of liquid-solid mixing in a mud shear mixer. And then, the simulation-based design of shear mixer are carried out to improve mixing performance in a mud handling system.

• Journal of Chitin and Chitosan
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• v.23 no.4
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• pp.267-276
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• 2018

This study was performed to investigate the ameliorating effect of a hangover beverage mixture (SBJ) that contains Dendropanax morbifera Lev. and several medicinal plant extracts, on hepatoprotection and alcohol-metabolizing enzymes in alcohol-induced hangover in both in vitro and in vivo models. In human hepatoma cell line, HepG2, 300 mM of ethanol-induced hepatotoxicity was significantly improved by pretreatment of SBJ by dose-dependent manner. In the in vivo study, administration of alcohol to rats raised to the concentration of blood alcohol and lactate dehydrogenase (LDH). Blood alcohol and LDH levels in SBJ-treated rats significantly decreased at 0.5 h and 8 h after acute ethanol administration (40%, 4.6 g/kg body weight) as compared to alcohol-treated rats. Hepatic alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity were significantly higher in SBJ-treated rats than in alcohol-treated rats. SBJ supplementation reduced formation of malondialdehyde (MDA), and inhibited reductions of hepatic superoxide dismutase (SOD), hepatic glutathione (GSH), glutathione-S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx) levels, compared with rats administered alcohol. Plasma catalase (CAT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels showed unaltered resulted in all experimental groups compared with the control group. These results suggest that SBJ exhibit hepatoprotective properties by enhancing ADH, ALDH activity and stimulating the antioxidant defense system in alcohol-induced hangover.

• Journal of Life Science
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• v.28 no.11
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• pp.1321-1331
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• 2018

The aim of this study was to separate the photosensitizer that induces apoptosis of U937 and SK-HEP-1 cells from Nostoc commune. Dried N. commune was extracted with $CH_2Cl_2/MeOH$ (1:1) to separate the photosensitizer using various chromatographic techniques. The isolated compound was identified as pheophytin a ($C_{55}H_{74}N_4O_5$) with a molecular weight of 870. Its photodynamic activities were assessed under different irradiation conditions (light and non-light) at the same concentration range of $1.15-23.0{\mu}M$. The apoptosis inducing activity in U937 or SK-HEP-1 cells appeared only in the light. The mechanisms underlying the pheophytin a-mediated photodynamic inhibition of cancer cells were further investigated by examining cell morphology changes, cytotoxicity, caspase-3/7 activity, fluorescence staining, flow cytometry analysis, and DNA fragmentation in these two cell lines. The positive control and the light irradiation group showed typical apoptotic responses, including morphological changes, cytotoxicity, caspase activity, nucleus shrinkage owing to chromatin condensation, DNA laddering, and the presence of apoptotic bodies. Cytotoxicity markedly increased in a dose-dependent manner after a 12 hr exposure. Caspase-3/7 activity was higher in U937 cells than in SK-HEP-1 cells. Apoptosis induction therefore appeared to be both concentration- and light-dependent. In conclusion, pheophytin a, isolated from the blue green alga N. commune, had a photodynamic apoptosis-inducing effect on U937 and SK-HEP-1 cells. The findings reported here can be used as basic data for the development of next-generation photosensitizers from N. commune.

• The Journal of Engineering Geology
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• v.29 no.2
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• pp.99-112
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• 2019

Rainfall infiltration through the unsaturated zone is influenced by a range of factors including topography, geology, soil, rainfall intensity, temperature and vegetation; the actual infiltration varies largely in time and space. The infiltration capacity of soil is a critical factor in identifying groundwater recharge and leakage of surface water. It may differ depending on soil types and geological features of a particular basin or territory as well as on the usage of the land. This study was conducted in forest and farmland region of the mid-mountain area (EL. 50~300 m) of Jeju Island to test soil infiltration capacity of the area where rainfall contributes to groundwater. Results were analyzed using the four soil group classification methods presented by Jeong et al. (1995) and NAS (2007) to discover that the method offered by NAS (2007) is more reliable in the mid-mountain area of Jeju Island. The study compares and reviews the existing classification methods using the results of infiltration capacity tests executed on different soil groups throughout the whole region of the Jeju mid-mountain area. It is expected that this work will serve as a guideline for evaluating surface water recharge and hydraulic characteristics of Jeju Island.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.6
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• pp.493-503
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• 2018

The present study is a conceptual replication of O'Grady, Lee, and Choo's (2003) earlier study designed to investigate two hypotheses (linear distance hypothesis vs. structural distance hypothesis) in relation to L2 Korean learners' processing of Korean subject and object relative clauses (RCs) in a scholarly attempt to explicate Keenan and Comrie's (1977) Noun Phrase Accessibility Hierarchy (NPAH). In addition, the current study is intended to explore any potential role of working memory capacity (WMC) in the processing of Korean subject and/or object RCs. Chinese-speaking learners of Korean taking a language course offered at a local university in Korea participated in this experimental study. Among those recruited, only 23 learners completed the experimental tasks appropriately according to the specific instructions provided on each task, and thus, subsequent statistical analyses were conducted on their data. Fifteen Korean NSs were also recruited for the control group. Two experimental tasks were administerd to the participants: one picture selection task containing the same test items used in O'Grady et al.'s study to measure their processing of subject-object RCs and an operation span (OSPAN) task to measure their WMC. Somewhat differently from O'Grady et al.'s findings, the participating Chinese learners of Korean performed significantly better on object RCs than on subject RCs, seemingly lending support to the linear distance hypothesis. Further analyses, however, suggested that the results in favor of, or relative ease of processing, object relative clauses were due, most likely, to the learners' excessive use of the canonical sentence strategy, which also led to nonsignificant correlations between WMC and learner performance on the picture selection task.

• Korean Journal of Plant Taxonomy
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• v.39 no.3
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• pp.170-180
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• 2009

Somatic chromosome counts and karyotype analyses were carried out for eight taxa of Korean Allium sect. Sacculiferum. The basic chromosome number of sect. Sacculiferum was x = 8, and they could be cytologically divided into two groups, that is, a diploid group (2n = 2x = 16) containing A. thunbergii var. thunbergii, A. thunbergii var. deltoides, A. thunbergii var. teretifistulosum, A. deltoidefistulosum, A. longistylum, A. linearifolium and A. taqueti, and a tetraploid group (2n = 4x = 32) with only A. sacculiferum. All observed chromosomes were classified into metacentric, submetacentric and subtelocentric. The metacentric ones appeared in all treated taxa. One or two pairs of submetacentric chromosomes were observed in most taxa except A. sacculiferum, the unique taxon with subtelocentric chromosomes. All taxa had a pair of homologous chromosomes with satellites, and the B-chromosomes found in A. thunbergii var. thunbergii, A. deltoidefistulosum, A. sacculiferum and A. longistylum, were metacentric or telocentric. The karyotypes of A. longistylum and A. linearifolium were firstly investigated in this study. In conclusion, the somatic chromosome numbers and karyotypes for members of the sect. Sacculiferum were valuable characters in identifying taxa, investigating interspecific relationships and delimiting taxa. In addition, A. thunbergii var. teretifolium, an invalid name (homonym), was renamed as A. thunbergii var. teretifistulosum H. J. Choi & B. U. Oh.

• Journal of Life Science
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• v.21 no.3
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• pp.435-443
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• 2011

The purpose of this study is to identify the effects of exercise training [ET, 10~18 m/min (speed), 20~30 min (exercise duration)/a day for 5 day/wk, 6 wk) on PGC-$1{\alpha}$, GLUT-1, Tfam, Cu,Zn-SOD and Mn-SOD proteins in brain of STZ-induced diabetic rats. The male Sprague-Dawley (SD) rats were single-injected intraperitoneally with 50mg/kg of streptozotocin (STZ) to produce STZ-induced diabetic rats. Rats were divided into 3 experimental groups with 8 rats in each group, as follows: (1) non-STZ group (n=8), (2) STZ-CON group (n=8), (3) STZ-EXE group (n=8). The results of this study suggest that i) serum glucose level was significantly reduced in STZ-EXE group compared with STZ-CON group (p<0.05), ii) PGC-$1{\alpha}$ (p<0.001), mtPGC-$1{\alpha}$ (p<0.001), GLUT-1 (p<0.001), and mtTfam (p<0.001) proteins in brain of STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group, iii) Cu,Zn-SOD (p<0.001) and Mn-SOD (p<0.01) proteins in the STZ-induced diabetic rats were significantly increased in STZ-EXE group compared with STZ-CON group. In conclusion, the findings of the present study reveal that treadmill exercise training increases brain GLUT-1 protein level possibly through up-regulation of PGC-$1{\alpha}$ and Tfam proteins which represent key regulatory components of stimulation of brain mitochondrial biogenesis. In addition, treadmill exercise training may prevent oxidative stress by up-regulation of Cu,Zn-SOD and Mn-SOD proteins in the STZ-induced diabetic rats.

• The Journal of Internal Korean Medicine
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• v.29 no.2
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• pp.500-511
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• 2008

The aim of this study was to investigate the inhibitory effect of Saengangeonbitang-gasamchilgn(SGGBTGSCG) on collagen production in rat hepatic stellate cells(HSC) and on the TAA-induced chronic liver injury model in rats. Methods : 1) HSCs were treated with SGGBTGSCG extract powder(50% EtOH SGGBTGSCG, dw SGGBTGSCG). After the treatment, MTT assay, BrdU assay and procollagen assay were done. In addition, gene expressions of collagen type $1{\alpha}2$, ASMA, TIMP1, and TIMP2, all of which are known to be associated with liver fibrosis, were analyzed by RT-PCR. 2) Liver fibrosis was developed in rats by injection of TAA 3 times a week for 5 weeks. After the SGGBTGSCG-treatment, body weight, liver & spleen weight, liver function test, the complete blood cell count and the change of portal pressure were studied. Results : In MTT assay, SGGBTGSCG significantly decreased the viability of HSCs in a dose-dependent manner. In BrdU assay, SGGBTGSCG significantly inhibited the HSC proliferation in a dose-dependant manner. In procollagen assay, SGGBTGSCG decreased procollagen production by HSC. In the change of rats' liver and spleen weight, TAA+SGGBTGSCG groups showed little difference compared with TAA-only group. In the liver function test, SGGBTGSCG decreased the serum level of ALT, AST, and Alp elevated by TAA. In the complete blood cell count, SGGBTGSCG significantly decreased WBC elevated by TAA and increased RBC and Hct lowered by TAA. In the change of portal pressure, SGGBTGSCG decreased portal pressure elevated by TAA. Conclusions : These results suggest that SGGBTGSCG is beneficial in the treatment of cirrhotic patients as well as for patients with chronic hepatitis.

• Imaging Science in Dentistry
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• v.44 no.3
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• pp.229-236
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• 2014

Purpose: To investigate the prevalence of bifid and trifid mandibular canals using cone-beam computed tomography (CBCT) images, and to measure their length, diameter, and angle. Materials and Methods: CBCT images of 500 patients, involving 755 hemi-mandibles, were used for this study. The presence and type of bifid mandibular canal was evaluated according to a modified classification of Naitoh et al. Prevalence rates were determined according to age group, gender, and type. Further, their diameter, length, and angles were measured using PACSPLUS Viewer and ImageJ 1.46r. Statistical analysis with chi-squared and analysis of variance (ANOVA) tests was performed. Results: Bifid and trifid mandibular canals were found in 22.6% of the 500 patients and 16.2% of the 755 sides. There was no significant difference between genders and among age groups. The retromolar canal type accounted for 71.3% of the identified canals; the dental canal type, 18.8%; the forward canal type, 4.1%; and the trifid canal type, 5.8%. Interestingly, seven cases of the trifid canal type, which has been rarely reported, were observed. The mean diameter of the bifid and trifid mandibular canals was 2.2 mm and that of the main mandibular canal was 4.3 mm. Their mean length was 16.9 mm; the mean superior angle was $149.2^{\circ}$, and the mean inferior angle was $37.7^{\circ}$. Conclusion: Bifid and trifid mandibular canals in the Korean population were observed at a relatively high rate through a CBCT evaluation, and the most common type was the retromolar canal. CBCT is suggested for a detailed evaluation of bifid and trifid mandibular canals before mandibular surgery.

• Korean Journal of Adult Nursing
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• v.13 no.3
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• pp.451-462
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• 2001

This study was conducted to examine and compare the characteristics in the cognitive functions of peritoneal dialysis, hemodialysis and normal kidney function groups as basic data for effectively educating dialysis patients. The data were collected from May 10 to October 30. 2000, collected from each of 20 patients with peritoneal dialysis, hemodialysis and normal Kidney function and who registered for the dialysis room at a general hospital affiliated to a university in Seoul and sampled by age and educational level through personal interviews with the researchers of this study. As a measuring tool, MMSE developed by Folstein et al.(1975) to measure cognitive function disorder was used, slightly revised for hemodialysis patients. Collected data were processed into frequency, percentage, mean, and standard deviation by the use of SAS. The results of this study are as follows : 1. With a maximum of 30 points for cognitive function, the mean of the peritoneal dialysis patients was $27.06{\pm}2.06$, while that of the hemodialysis patients was $27.25{\pm}2.76$; that of the normal Kidney function patients was $27.85{\pm}2.00$, indicating no significant difference among those three groups. 2. As for the subjects who scored 23 points, the turning point of confirming the cognitive disorder, the percentage was 5% in the case of the peritoneal dialysis, 10% in the case of the hemodialysis and 5% in the case of the normal Kidney function group. 3. Differences between the peritoneal dialysis and hemodialysis patients by gender, occupation, spouse, diabetes, hypertension, the period of dialysis, number of hospitalizations, and the use of erythropoietin were not significant in the scoring of cognitive function. 4. There was no significant correlation between the level of Hb, Hct, albumin, aluminium, PTH, BUN, Cr, dialysis adequacy and the cognitive function. Considering such results, it is clear that there is no significant difference in the cognitive functions of the sampled subjects. Therefore, the nurse in the dialysis room should continually carry out assessment and intervention against elements degrading the effect of patients' education to improve self- care.