• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.669-676
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• 2010

This study was performed to investigate the effect of Brassica rapa (BR) sprouts on weight reduction and cholesterol-lowering action in rats fed high fat diet for 4 weeks. Weight-matched male Sprague-Dawley rats were assigned to four groups according to dietary fat levels (10% or 20% of diet wt.). Experimental groups were normal diet group (N), high fat diet group (HF), high fat diet with 5% BR sprouts powder group (HF-BRL), and high fat diet with 10% BR sprouts powder group (HF-BRH). The body weight gain was increased in HF group, but gradually decreased to the corresponding level of the N group fed BR sprouts powder. The concentrations of serum LDL-cholesterol, atherogenic index and cardiac risk factor tended to decrease in the BR sprouts powder fed groups compared with the HF group. However, HDL-cholesterol concentration in serum decreased in the HF group and markedly increased in the BR sprouts powder fed groups. Concentrations of triglyceride and total cholesterol in liver were also markedly decreased in the BR sprouts powder fed groups. Triglyceride concentrations of epididymal and mesenteric adipose tissues in the BR sprouts powder fed groups were also decreased compared with the HF group. These results indicate that BR sprouts powder may reduce fat accumulation and body weight, and have cholesterol-lowering effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6373-6386
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• 2013

This study examined the relationship between the MBTI character types and heart rate variability. The subjects were 25 students in the department of emergency medical technology in C city, Chungnam, Korea. The heart rate variability was measured under two conditions: a stable state, and in the second week and fourth week in clinical practice. The period of the heart rate variability measurements was from Jun. 21, 2013 to Jul. 26, 2013.The changes in the HRV at the stable state and during clinical practice depending on the MBTI character types, and the HRV at the stable state and during clinical practice according to the distribution chart of four character types showed a significant difference in the nHF and standard deviation of all R-R intervals (SDNN). In the changes in the HRV at the stable state and during clinical practice depending on the preference distribution chart of each indicator, the T-F group and J-P group in the nLF, T-F group and J-P group in the nHF, S-N group in the standard deviation of all R-R intervals (SDNN) and the J-P group in the mHR showed a significant difference.

• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.54.1-54.10
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• 2021

Objectives: The purpose of this study was to quantify phase transformation after hydrofluoric acid (HF) etching at various concentrations on the surface of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), and to evaluate changes in bonding strength before and after thermal cycling. Materials and Methods: A group whose Y-TZP surface was treated with tribochemical silica abrasion (TS) was used as the control. Y-TZP specimens from each experimental group were etched with 5%, 10%, 20%, and 40% HF solutions at room temperature for 10 minutes. First, to quantify the phase transformation, Y-TZP specimens (n = 5) treated with TS, 5%, 10%, 20% and 40% HF solutions were subjected to X-ray diffraction. Second, to evaluate the change in bond strength before and after thermal cycling, zirconia primer and MDP-containing resin cement were sequentially applied to the Y-TZP specimen. After 5,000 thermal cycles for half of the Y-TZP specimens, shear bond strength was measured for all experimental groups (n = 10). Results: The monoclinic phase content in the 40% HF-treated group was higher than that of the 5%, 10%, and 20% HF-treated groups, but lower than that of TS-treated group (p < 0.05). The 40% HF-treated group showed significantly higher bonding strength than the TS, 5%, and 10% HF-treated groups, even after thermal cycling (p < 0.05). Conclusions: Through this experiment, the group treated with SiO₂ containing air-borne abrasion on the Y-TZP surface showed higher phase transformation and higher reduction in bonding strength after thermal cycling compared to the group treated with high concentration HF.

• Analytical Science and Technology
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• v.21 no.2
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• pp.84-92
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• 2008

A method for the determination of trace amount of caffeine in urine and various drink samples using hollow fiber-liquid phase microextraction (HF-LPME) and capillary gas chromatograph/nitrogen phosphorus detector (GC/NPD) has been established. HF-LPME method has been optimized with respect to several experimental parameters including the effects of the hollow fiber length, extraction solvent, stirring mode, pH and salt concentration for the determination of caffeine from aqueous samples. The correlation coefficient of calibration curve for caffeine was 0.9994. The average recovery was 102%(n=3). The established method is feasible for the determination of trace amounts of caffeine in several aqueous sample. The limit of detection (LOD) and the limit of quantitation (LOQ) have been found to be 2.5 and 10 ng/mL, respectively. The established HF-LPME method for the analysis of caffeine from aqueous sample can be used for the determination of biological, food and environmental samples.

• Korean Journal of Materials Research
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• v.16 no.8
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• pp.473-478
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• 2006

The coherent interface energies and misfit strain energies of Fe/XN (X=Ti, Zr, Hf) systems were calculated by first principles method. The interface energies in Fe/TiN, Fe/ZrN and Fe/HfN systems were 0.343, 0.114, and 0.030 $J/m^2$, respectively. Influence of bond energy was estimated using the discrete lattice plane/nearest neighbor broken bond(DLP/NNBB) model. It was found that the dependence of interface energy on the type of nitride was closely related to changes of the bond energies between Fe, X and N atoms before and after formation of the Fe/XN interfaces. The misfit strain energies in Fe/TiN, Fe/ZrN, and Fe/HfN systems were 0.239, 1.229, and 0.955 eV per 16 atoms(Fe; 8 atoms and XN; 8 atoms). More misfit strain energy was generated as the difference of lattice parameters between the bulk Fe and the bulk XNs increased.

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.847-851
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• 1998

13C, 15N, and 29Si NMR chemical shifts have been computed for selected X-substituted silatranes (X=Cl, F, H, CH3) using Gauge-Including Atomic Orbitals (GIAO) and Continuous Set of Gauge Transformations (CSGT) at the Hartree-Fock level of theory. The isotropic 13C chemical shifts are largely insensitive to substituent-induced structural changes. In this study, the isotropic 13C chemical shifts GIAO and CSGT calculations at the HF/6-31G and HF/6-31G* levels are sufficiently accurate to aid in experimental peak assignments. The isotropic 13C chemical shifts X-substituted silatranes at HF/6-31G* level are approximately 4 ppm different from the experimental values. In contrast, the isotropic 15N and 29Si chemical shifts and the chemical shielding tensors are quite sensitive to substituent-induced structural changes. These trends are consistent with those of the experiment. The 15N chemical shift parameters demonstrate a very clear correlation with Si-N distance, especially when we use the polarization function. Changes in anisotropy, 3a as well as in the 15N isotropic chemical shifts are due primarily to changes in the value of a.. But in case of "Si the correlations are not as clean as for the 15N chemical shift.

• Journal of Life Science
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• v.28 no.1
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• pp.83-89
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• 2018

This study was attempted to investigate the effects of Duchesnea chrysantha (DC) on antioxidative activities by in vivo. Rats were divided into four experimental groups which are composed of normal diet group (N group), high fat high cholesterol diet group (HF group), high fat high cholesterol diet with 5% DC powder supplemented group (DA group) and high fat high cholesterol diet with 10% DC powder supplemented group (DB group). Supplementation of DC powder groups resulted in increased activities of hepatic glutathione peroxidase and catalase. The microsomal superoxide radical contents of the DA and DB groups were significantly reduced compared to the high fat high cholesterol diet group. The mitochondrial superoxide radical contents of the DB group were significantly reduced compared to the high fat high cholesterol diet group. Hepatic hydrogen peroxide contents in cytosol were significantly reduced 5% and 10% DC powder supplemented group. The carbonyl values contents in mitochondria and microsome of the DA and DB groups were significantly reduced compared to the HF group. Thiobarbituric acid reaction substance (TBARS) values in liver were reduced in 10% DC powder supplemented group compared to the HF group. These results suggest that DC powder may have a strong regulatory effect in the activation of the antioxidative defense system.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.222-223
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• 2002

자기헤드에서 사용되는 연자성 박막에서 요구되는 특성 중 가장 중요한 것은 우수한 연자기 특성의 화보와 헤드제조공정에서 필수적인 유리접합공정(MIG 헤드의 경우 약 500~600 $^{\circ}C$의 열처리) 이후에도 연자기 특성이 유지되는 내열성이다. 이러한 관점에서 우수한 연자기 특성과 내열성을 동시에 보유하는 연자성 박막재료에 대한 연구가 활발히 진행되어 Fe-TM(Hf, Zr. Ta 등)-(B. C, N) 계 등이 보고되었다[1-4]. (중략)

• Korean Journal of Exercise Nutrition
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• v.13 no.2
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• pp.93-100
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• 2009

This study was conducted to investigate the effect of exercise training on blood and metabolic variances and genes expressions in hyperlipidemic rats. Three weeks-old male rats were randomly assigned into chow (n=7), high-fat diet (HF, n=7) and HF+exercise (HF+EX, n=7) groups. Exercise training consisted of the treadmill running 5 times per week during 8 weeks (0% grade, 30 min/time for first 4 weeks and 0% grade, 60 min/time the other 4weeks). The levels of triglyceride and total -cholesterol were increased in HF diet compared with chow group, and recovered to level of chow group by exercise training. Plasma glucose and insulin concentrations increased by 40 and 50%, respectively in HF diet compared with chow diet group, and these increases returned to the level of chow group by exercise training (p<.05). Body weight and abdominal fat mass were increased by high-fat diet compared with chow diet, and recovered to level of chow group by exercise training. Long-chain fatty acid oxidation rate and AMPK protein expression was not changed by HF diet, but increased by exercise training compared with high-fat diet (p<.05). UCP3 protein expression was not changed by either high-fat diet or exercise training compared with chow group. There was high correlation between plasma triglyceride and total cholesterol concentrations(p<.01). Plasma triglyceride or total cholesterol level showed correlation with following factors; plasma insulin and glucose levels, body weight, abdominal fat weight, UCP3 protein expression and long-chain fatty acid oxidation rate. These results showed that exercise training on the treadmill recovered hyperlipidemia, hyperglycemia and hyperinsulinemia induced by high-fat diet for 8 weeks. These exercise effects may be related with decreased body weight and abdominal fat mass, and increased long-chain fatty acid oxidation rate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.24-25
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• 2008

The effect of heat treatment in $HfO_2$ as charge trap with $SiO_2/Si_3N_4/SiO_2$ as tunnel oxide layer in capacitors has been investigated. Rapid thermal annealing (RTA) were carried out at the temperature range of 600 - $900^{\circ}C$. It is found that all devices carried out heat treatment have large threshold voltage shift Especially, device performed heat treatment at $900^{\circ}C$ has been confirmed the largest memory window. Also, Threshold voltage shift of device used conventional $SiO_2$ as tunnel oxide layer was smaller than that with $SiO_2/Si_3N_4/SiO_2$.