• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.475-483
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• 2012

High capacitance X5R MLCCs based on $BaTiO_3$ ceramic dielectric layers exhibit a single broad, asymmetric arc shape impedance and modulus response over the wide frequency range between 1 MHz to 0.01 Hz. Analysis according to the conventional brick-layer model for polycrystalline conductors employing a series connection of multiple RC parallel circuits leads to parameters associated with large errors and of little physical significance. A new parametric impedance model is shown to satisfactorily describe the experimental spectra, which is a parallel network of one resistor R representing the DC conductivity thermally activated by 1.32 eV, one ideal capacitor C exactly representing bulk capacitance, and a constant phase element (CPE) Q with complex capacitance $A(i{\omega})^{{\alpha}-1}$ with ${\alpha}$ close to 2/3 and A thermally activated by 0.45 eV or ca. 1/3 of activation energy of DC conductivity. The feature strongly indicate the CK1 model by J. R. Macdonald, where the CPE with 2/3 power-law exponent represents the polarization effects originating from mobile charge carriers. The CPE term is suggested to be directly related to the trapping of the electronic charge carriers and indirectly related to the ionic defects responsible for the insulation resistance degradation.

• Korean Journal of Environmental Agriculture
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• v.13 no.1
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• pp.10-17
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• 1994

To investigate differences with the polluted sources on Cu contents in soils and paddy rices under water pollutions, soils with the distance, the surface(0-15㎝ depth) and subsurface(15-30㎝ depth) in 1982 and 1990, and rice plants at the soil sampling sites in 1990 were separately sample at Mangyeong River area under the influence of municipal and industrial waste water from Jeonju city. Soil samples were extracted with $4M-HNO_3$ and plant samples were digested with mixture of $HNO_3$ and $HClO_4$ for analyzing Cu, Cd, Zn, Pb by atomic absorption spectrophotometry. Cu contents in soils ranged from 5.20 to 71.70 mg $kg^{-1}$. Average Cu level in 1990 was higher than that in 1982. Variation of Cu content with the distances from the source of waste water in 1990 was more regularly decreased than that in 1982. A significant correlation was observed between Cu contents in leaf sheath of rice plant and Cu, Zn and Pb contents in soils. Cu contents in soil was correlated with Zn and Pb in soil at area affected by waste water, regardless of years and soil depths. Cu contents in brown rice ranged from 0.4 to 10 mg $kg^{-1}$, and it was the lowest in parts of rice plant, and Cu content in panicle axis was 2.3 times higher than that in brown rice.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1263-1269
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• 1999

An FBAR(Solidly Mounted Resonator) was fabricated using reflector layers which prohibit the penetration of bulk acoustic wave into substrate. The SMR consisted of top and bottom electrodes(Al films), a piezoelectric layer (ZnO film), reflector layers(W/$Si_2$ films) and Si substrate. The electrodes were deposited by dc sputtering. The piezoelectric layer and the reflector layers were deposited by rf magnetron sputtering. The control of crystallinity, microstructures and electric properties of each layer was essential for attaining the optimum FBAR characteristics. Under the best deposition conditions for FBAR devices, the ZnO films had highly c-axis preferred orientation(${\sigma}=2.17^{\circ}$), resistivity of $10^4\;{\omega}cm$, and surface roughness of 10.6 ${\AA}$. On the other hand, the surface roughness of W and $Si_2$ films was 16 ${\AA}$ and 33 ${\AA}$, respectively, and the resistivity of Al film was $5.1{\times}10^{-6}\;{\Omega}cm$. The SMR devices were fabricated by the conventional semiconductor processes. In the resonance conditions of the SMR, the series resonance frequency (fs) and the parallel resonance frequency(fp) were 1.244 GHz and 1.251 GHz, respectively and the quality factor(Q) was 1200.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.87-94
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• 2017

Tissue engineering (TE) has been developed to create functional organs and tissue by combining 3D matrix and cells in vitro. Vascularization and angiogenesis are utmost important for supply of nutrients and oxygen in tissue engineered organs. The present study was performed to isolate and characterize primary endothelial cells (EC) from aorta of alpha 1, 3-enzyme galactosyltransferase knock out (GalT KO) pig, to minimize immune rejection and analyze body immune system for future xenotransplantation studies. Isolation of primary EC from aorta were performed by incubation with dispase for 8-10 min at $37^{\circ}C$. Primary EC were cultured in EC growth medium on different extra cellular matrix (ECM), either collagen or gelation. Primary EC exhibits morphological characteristics and showed positive expressions of EC specific marker proteins i.e. PECAM1, KDR and VWF despite of their ECM surface; however, on collagen based surface they showed increase in mRNA level analyzed by qPCR. Primary EC cultured on collagen were sorted by flow cytometer using KDR marker and cultured as KDR positive cells and KDR negative cells, respectively. KDR positive cells showed dramatically increased in PECAM1 and VWF level as compared to KDR negative cells. Based on the above results, primary EC derived from GalT KO are successfully isolated and survived continuously in culture without becoming overgrown by fibroblast. Therefore, they can be utilize for xeno organ transfer, tissue engineering, and immune rejection study in future.

• Childhood Kidney Diseases
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• v.12 no.1
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• pp.88-92
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• 2008

Infection of Epstein-Barr virus(EBV) gives rise to a broad spectrum of clinical manifestations in children. Although renal involvement is rare, diverse renal manifestations are known from hematuria to acute renal failure. Secondary membranous nephropathy(MN) associated with systemic EBV infection is an uncommon renal pathology and only two cases have been reported. We are adding another case of MN associated with EBV infection in a child. An 8-year-old girl was admitted for renal biopsy. She had been followed up for microscopic hematuria and intermittent proteinuria for 5 months. There had been no specific findings in serology and radiology. Tonsil biopsy had been done due to exudative tonsillar hypertrophy and enlarged multiple cervical lymph nodes. And it showed EBV-associated lymphoproliferative findings. Serologic tests for EBV showed positive evidence of recent infection; viral capsid antigen(VCA) IgM was borderline positive, VCA IgG and early antigen IgG were positive, and EB nuclear antigen IgG was negative. In Situ Hybridization of tonsil for EBV mRNA was positive. Because her proteinuria and hematuria were aggravated at that time(protein 3 +, RBC >60/HPF), renal biopsy was done. Renal biopsy showed the findings of MN, characterized by thickened capillary walls with epimembranous spikes on light microscopy and subepithelial, mesangial and subendothelial electron dense deposits on electron microscopy. On immunofluorescence microscopy, IgG, C1q, kappa and lambda chains were positive. After steroid administration, proteinuria and hematuria resolved gradually within 6 months.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.30-38
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• 2000

Purpose: We investigated the role of myocardial perfusion SPECT in prediction of ventricular dilatation and the role of revascularization including thrombolytic therapy and PTCA in prevention of ventricular dilatation after an acute myocardial infarction (AMI). Materials and Methods: We performed dipyridamole stress, 4 hour redistribution, and 24 hour reinjection Tl-201 SPECT in 16 patients with AMI two to nine days after attack. Perfusion and wall motion abnormalities were quantified by perfusion index (PI) and wall motion index (WMI). Left ventricular ejection fraction (LVEF), WMI and ventricular volume were measured within 1 week of AMI and after average of 6 months. According to serial changes of left ventricular end-diastolic volume (LVEDV), patients were divided into two groups. We compared WMI, PI and LVEF between the two groups. Relationships among degree of volume, stress-rest PI, WMI, CKMB, Q wave, LVEF and revascularization were analysed using multivariate analysis. Results: Only initial rest perfusion index was significantly different between the two groups (p<0.05). While initial LVEF, stress PI, CKMB, trial of revascularization procedure, presence of Q wave and WMI were not significantly different between the two groups. Eight of 16 patients (50%) showed LV dilatation on follow-up echocardiography. Three of 3 patients (100%) who did not undergo revascualrization procedure documented LV dilatation. And only 5 (38%) of the remaining 13 patients who underwent revascularization revealed LV dilatation. There was no difference in infarct location between the two groups. By multivariate linear regression analysis in patients only undergoing revascularization, rest perfusion index was the only significant factor. Conclusion: Myocardial perfusion SPECT performed prior to revascularization was useful in prediction of LV dilatation after an AMI. Rest perfusion index on myocardial perfusion plays as a significant predictor of left ventricular dilatation after AMI. And revascularization appears to be a valuable procedure in alleviating LV dilatation after AMI with or without viable myocardium in a limited number of patients studied retrospectively.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.32-38
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• 2003

Objectives: The purpose of this study is to investigate the effects of stress and personality on sleep patterns, and further, to identify potential correlations between stress and personality characteristics. Methods: A total of 174 healthy college students were subjects for this study. Participants filled out the Daily Stress Inventory before sleep and the Modified Pittsburgh Sleep Quality Index after sleep on three consecutive days. They also filled out the 16 Personality Factor Questionnaire (16-PF), BDI (Beck Depression Inventory) and STAI (State-Trait Anxiety Inventory). Results: Minor stresses highly correlated with subjective sleep quality and symptoms of non-restorative sleep. However, total sleep time, sleep latency, awakening frequency, and frequency of dreams were not explained by stress scores. The O (guilty feeling), C (low ego strength) and Q4 (high anxiety) factors of the 16-PF also highly correlated with symptoms of non-restorative sleep and significantly affected sleep patterns. BDI and STAI scores also correlated with the above personality factors and minor stresses. Conclusion: This study showed that minor stresses impaired the restorative effects of sleep. Personality characteristics such as low ego strength, high levels of anxiety, and feelings of guilt were vulnerable to minor stresses. Minor stress, various personality characteristics, different coping patterns, and emotional response are highly correlated with each other and affect sleep patterns.

• Journal of Nutrition and Health
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• v.54 no.2
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• pp.139-151
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• 2021

Purpose: This study examines the correlation between fish consumption and the risk of mild cognitive impairment in the elderly living in rural areas. Methods: The Yangpyeong cohort data collected from Yangpyeong in July 2009 and August 2010 was used as the data set. Adults greater than or equal to 60 years who have completed the Korean version of the Mini-Mental State Examination (MMSE-KC) were selected for the study. After excluding participants with less than 500 kcal of energy intake (n = 2), a total of 806 adults were enrolled as the final subjects. Cognitive function was assessed using the MMSE-KC, and dietary intake was collected using the quantitative food frequency questionnaire comprising 106 foods or food groups. Results: The educational level, proportion of people who exercise, fruits and vegetable intake, and energy intake, tended to increase with fish intake among men, while increasing age resulted in decreased fish consumption. Among women, the educational level, proportion of subjects who exercise, proportion of subjects currently taking dietary supplements, fruits and vegetable intake, and energy intake, tended to increase with fish consumption, whereas increasing age showed decreasing fish consumption. Increased fish intake resulted in a higher MMSE-KC score after adjusting for the confounding variables in women (p for trend = 0.016), but no significant trend was observed between fish intake and MMSE-KC score in men. Fish intake was inversely related to the risk of mild cognitive impairment after adjusting for covariates in women (Q1 vs. Q4; odds ratio, 0.46 [0.23-0.90]; p for trend = 0.009). Conclusion: This study determined that increased fish consumption is correlated with reduced risk of mild cognitive impairment in the female elderly. Further longitudinal studies with larger samples are required to determine a causal relationship between fish intake and cognitive function.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.380-389
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• 2007

Stable carbon and nitrogen isotopes were analyzed in suspended particulate organic matter, macroalgae and macrobenthic invertebrates in order to determine the importance of primary organic matter sources in supporting food webs of rocky subtidal and intertidal macroalgal beds in the Korean coasts. Investigations were conducted at the inter tidal sites within Gwangyang bay, a semi-enclosed and eutrophicated bay, and the subtidal sites of the east coast, a relatively oligotrophic and open environment, in May and June 2005. Water-column suspension feeders showed more negative $\delta^{13}C$ values than those of the other feeding guilds, indicating trophic linkage with phytoplankton and thereby association with pelagic food chains. In contrast, animals of the other feeding guilds, including interface suspension feeders, herbivores, deposit feeders, omnivores and predators, displayed relatively less negative $\delta^{13}C$ values than those of the water-column suspension feeders and similar with that of macroalgae, indicating exclusive use of macroalgae-derived organic matter and association with benthic food chains. Most the macrobenthic species were considered to form strong trophic links with benthic food chains. In addition, the distribution of higher $\delta^{15}N$ values in macrobenthic consumers and macroalgae at the intertidal sites of Gwangyang Bay than those at the subtidal sites of the east coast suggests that anthropogenic nutrients may enhance the macroalgal production at the intertidal sites and in turn be incorporated into the particular littoral food web in Gwangyag Bay. These results confirm the dominant role of macroalgae in supporting rocky subtidal and intertidal food webs in the Korean coasts.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.6
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• pp.847-854
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• 2015

The objective of this study was to determine the effects of graded inclusions of wheat bran (0%, 9.65%, 48.25% wheat bran) and two growth stages (from 32.5 to 47.2 kg and 59.4 to 78.7 kg, respectively) on the apparent ileal digestibility (AID), apparent total tract digestibility (ATTD) and hindgut fermentation of nutrients and energy in growing pigs. Six light pigs (initial body weight [BW] $32.5{\pm}2.1kg$) and six heavy pigs (initial BW $59.4{\pm}3.2kg$) were surgically prepared with a T-cannula in the distal ileum. A difference method was used to calculate the nutrient and energy digestibility of wheat bran by means of comparison with a basal diet consisting of corn-soybean meal (0% wheat bran). Two additional diets were formulated by replacing 9.65% and 48.25% wheat bran by the basal diet, respectively. Each group of pigs was allotted to a $6{\times}3$ Youden square design, and pigs were fed to three experimental diets during three 11-d periods. Hindgut fermentation values were calculated as the differences between ATTD and AID values. For the wheat bran diets, the AID and ATTD of dry matter (DM), ash, organic matter (OM), carbohydrates (CHO), gross energy (GE), and digestible energy (DE) decreased with increasing inclusion levels of wheat bran (p<0.05). While only AID of CHO and ATTD of DM, ash, OM, CHO, GE, and DE content differed (p<0.05) when considering the BW effect. For the wheat bran ingredient, there was a wider variation effect (p<0.01) on the nutrient and energy digestibility of wheat bran in 9.65% inclusion level due to the coefficient of variation (CV) of the nutrient and energy digestibility being higher at 9.65% compared to 48.25% inclusion level of wheat bran. Digestible energy content of wheat bran at 48.25% inclusion level (4.8 and 6.7 MJ/kg of DM, respectively) fermented by hindgut was significantly higher (p<0.05) than that in 9.65% wheat bran inclusion level (2.56 and 2.12 MJ/kg of DM, respectively), which was also affected (p<0.05) by two growth stages. This increase in hindgut fermentation caused the difference in ileal DE (p<0.05) to disappear at total tract level. All in all, increasing wheat bran levels in diets negatively influences the digestibility of some nutrients in pigs, while it positively affects the DE fermentation in the hindgut.