• Toxicological Research
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• v.11 no.1
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• pp.161-168
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• 1995

It has been found that various stress challenges induce the myocardial antioxidant enzymes and produce an acquisition of the cellular resistance to the ischemic injury in animal hearts. Most of the stresses, however, seem to be guite dangerous to an animal's life. In the present study, therefore, we tried to search for safely applicable stress modalities which could lead to the induction of antioxidant enzymes and the production of myocardial tolerance to the ischemia-reperfusion injury. Male Sprague-Dawley rats (200-250 g) were exposed to various non-fatal stress conditions, i.e., hyperthermia (environmental temperature of $42^{\circ}C$ for 30 min, non-anesthetized animal), iramobilization (60 min), treadmill exercise (20 m/min, 30min), swimming (30 min), and hyperbaric oxyflenation (3 atm, 60 min), once a day for 5 days. The activities of myocardial antioxidant enzymes and the ischemia-reperfusion injury of isolated hearts were evaluated at 24 hr after the last application of the stresses. The activities of antioxidant enzymes, superoxide dismutase (SOD), catalase, glutathione peroxidase, glutathione reductase and glucose-6-phosphate dehydrogenase (G6PD), were assayed in the freshly excised ventricular tissues. The ischemia-reperfusion injury was produced by 20 min-global ischemia followed by 30 min-reperfusion using a Langendorff perfusion system. In swimming and hyperbaric oxygenation groups, the activities of SOD and G6PD increased significantly and in the hyperthermia group, the catalase activity was elevated by 63% compared to the control. The percentile recoveries of cardiac function at 30 min of the post-ischemic reperfusion were 55.4%, 73.4%, and 74.2% in swimming, the hyperbaric oxygenation and the hyperthermia groups, respectively. The values were significantly higher than that of the control (38.6%). In additions, left ventricular end-diastolic pressure and lactate dehydrogenase release were significantly reduced in the stress groups. The results suggest that the antioxidant enzymes in the heart could be induced by the apparently safe in vivo-stresses and this may be involved in the myocardial protection from the ischemia-reperfusion injury.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.654-658
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• 2000

Flavor components focused on the methyl pyrazines(2,3-dimethyl pyrazine, 2,3,5-trimethyl pyrazine, tetramethyl pyrazine) of microwave-roasted cocoa beans were determined and compared with those of conventionally-roasted cocoa beans. Domestic microwave oven was modified to design the microwave roasting system. Temperature measurement technique using thermocouple probes was developed to determine the center temperature of cocoa beans during microwave roasting. Microwave roasting was carried out under two different conditions. Under the first condition, roasting time was fixed to 30 min, while roasting temperature was varied to $110^{\circ}C,\;120^{\circ}C,\;130^{\circ}C,\;140^{\circ}C,\;and\;150^{\circ}C$ Under the second condition, roasting temperature was fixed to $130^{\circ}C$, while roasting time was varied to 5 min, 10 min, 20 min, and 30 min. Conventional roasting was done at $120^{\circ}C$ for 15 min as a reference. Amount of methyl pyrazines and their ratios were influenced by microwave roasting temperature and roasting time. The most suitable methyl pyrazine ratio of cocoa beans was obtained at $140^{\circ}C$ for 30 min of microwave roasting.

• Journal of Chest Surgery
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• v.32 no.11
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• pp.978-983
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• 1999

Background: Complement activation with transpulmonary leukocyte sequestration is considered a main mediator leading to ischemia-reperfusion lung(I-R) injury. We studied the role of leukocytes in the formation of I-R injury in ovine cardiopulmonary bypass(CPB) model with a membrane oxygenator. Material and Method: Five sheep were used. CPB circuitry consisted of a roller pump(American Optical Corp., Greenwich, CT, USA) and a membrane oxygenator(UNIVOX-IC, Bentley, Baxter Health Corp, Irvine, CA, USA). The CPB time was fixed at 120 min. Ten minutes after the start of CPB, total CPB was established. Thereafter a total CPB of 100 min was performed, followed by another 10 min of partial CPB. The CPB was discontinued and the animals were fully recovered. For measuring left and right atrial leukocyte counts, blood samples were taken before thoracotomy, 5 min and 109 in after the start of CPB, and 30 min and 120 min after weaning. C3a was measured before thoracotomy, 109 min after the start of CPB, and 30 min and 120 min after weaning. Plasma malondialdehyde(MDA) was checked before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. One to two grams of lung tissue were taken for water content measurement before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. Lung biopsy specimens were examined by light and electron microscopy. Result: Of 5 animals, 4 survived the experimental procedures. Of these, 3 animals survived on a long-term basis. No significant differences in transpulmonary gradients of leukocyte were found and no significant complement activation was expressed by C3a levels. MDA level did not show significant changes related to lung reperfusion despite an increase after the start of CPB. On both light and electron microscopic examinations, mild to moderate acute lung change was observed. Interstitial edema, leakage of erythrocytes into the alveolar space and endothelial cell swelling were the main findings. Water content of the lung showed a slight increase after the start of CPB, but there was no statistical significance. Conclusion: These findings indicate that ischemia-repersusion lung injury may not be from complement activation-leukocyte sequestration but from another source of oxygen free radicals related to CPB.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.513-521
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• 2000

This study was carried out to investigate the effects of electrical stimulation on the change Tyrosine-Hydroxylase immunoreactive(TH-IR) cells in the Central gray and retrorubral field of the male SD rats. 9 healthy and normal rats were divided into three groups, 3 SD rat in each group. The one group has been stimulated by electroacupuncture(EA, 2Hz) for 30min and the other group by EA for 1hr 30min and control group has been stimulated. TH-IR cells were found in the Central gray(CG) and Retrorubral field(RF). The numbers of TH-IR cells of CG and RF were significantly increased after 30 min (CG $6.2{\pm}0.83$, RF $1.4{\pm}0.55$)as compared with control group(CG $24{\pm}3.16$, RF $6.4{\pm}0.55$) and were also significantly increased after 1hr 30min(CG $75.6{\pm}4.51$, RF $18.8{\pm}0.89$) than 30min. These results show that TH is related into CG and RF in response to electrical stimulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.413-417
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• 1998

In this paper, we investigate frequency dependance of inductance of FeCoB amorphous magnetic films. $(Fe_{1-x}Co_x)_{79}Si_2B_{19}$ was used as the basic composition of amorphous magnetic film having near zero magnetostriction. The amorphous magnetic films were fabricated with x=0.94 and x=0.95 by using sputtering method at high frequency. The films were anneald under non-magnetic field and near crystallization temperatures(30min at $280^{\circ}C$, 30min and 1hr at $400^{\circ}C$, respectively). As the results of the experiments with the fabricated films, the lowest coercive force was 0.084[Oe] at 400[W] of the input power and the crystallization temperature was $360^{\circ}C$ . In the case 30min at 40$0^{\circ}C$ the inductance value in the low frequency with x=0.95 was higher by 488% than that with x=0.94. The quality factor Q was below 0.7 for all samples. We obtained the highest quality value at 400[KHz] with 30min at $280^{\circ}C$ and x=0.94. The value was about 0.62. Also, the quality factor value was about 0.35 at 1[MHz] with 30min at $280^{\circ}C$ and x=0.95.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.45-51
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• 2015

This study was full-scale combustion test for flame growth characteristics and temperature characteristics analysis to predict the risk of household Items fire when fire occurs. Experimental results, Refrigerator flames were the highest measured in 15 min time, and Washing machine is between 20 ~ 30 min, Drawer is 5 min, Sofa was enabled up to the size of the flame 15 min. In addition, the maximum combustion temperature was found from the time 20 min ~ 25 min, Sofa is temperature was elevated up to $1190^{\circ}C$, Refrigerator is $1,162^{\circ}C$, Drawer is $822^{\circ}C$, Washing machine appeared to be rising up to $670^{\circ}C$. Therefore, in the case of the maximum temperature of combustion Sofa it showed relatively high.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.169-177
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• 2020

Here, the stability of stainless steel 316 (SS-316) was investigated to identify its applicability in the oxide reduction process, as a component in related equipment, to produce a complicated gas mixture composed of O₂ and Cl₂ under an argon (Ar) atmosphere. The effects of the mixed gas composition were investigated at flow rates of 30 mL/min O₂, 20 mL/min O₂ + 10 mL/min Cl₂, 10 mL/min O₂ + 20 mL/min Cl₂, and 30 mL/min Cl₂, each at 600℃, during a constant argon flow rate of 170 mL/min. It was found that the corrosion of SS-316 by the chlorine gas was suppressed by the presence of oxygen, while the reaction proceeded linearly with the reaction time regardless of gas composition. Surface observation results revealed an uneven surface with circular pits in the samples that were fed mixed gases. Thermodynamic calculations proposed the combination of Fe and Ni chlorination reactions as an explanation for this pit formation phenomenon. An exponential increase in the corrosion rate was observed with an increase in the reaction temperature in a range of 300 ~ 600℃ under a flow of 30 mL/min Cl₂ + 170 mL/min Ar.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.22-27
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• 2014

Purpose There is the recent PET/CT scan in tendency that use low dose to reduce patient's exposure along with development of equipments. We diminished $^{18}F$-FDG dose of patient to reduce patient's exposure after setting up GE Discovery 690 PET/CT scanner (GE Healthcare, Milwaukee, USA) establishment at this hospital in 2011. Accordingly, We evaluate acquisition time per proper bed by change of infusion dose to maintain quality of image of PET/CT scanner. Materials and Methods We inserted Air, Teflon, hot cylinder in NEMA NU2-1994 phantom and maintained radioactivity concentration based on the ratio 4:1 of hot cylinder and back ground activity and increased hot cylinder's concentration to 3, 4.3, 5.5, 6.7 MBq/kg, after acquisition image as increase acquisition time per bed to 30 seconds, 1 minute, 1 minute 30 seconds, 2 minute, 2 minutes 30 seconds, 3 minutes, 3 minutes 30 seconds, 4 minutes, 4 minutes 30 seconds, 5 minutes, 5 minutes 30 seconds, 10 minutes, 20 minutes, and 30 minutes, ROI was set up on hot cylinder and back radioactivity region. We computated standard deviation of Signal to Noise Ratio (SNR) and BKG (Background), compared with hot cylinder's concentration and change by acquisition time per bed, after measured Standard Uptake Value maximum ($SUV_{max}$). Also, we compared each standard deviation of $SUV_{max}$, SNR, BKG following in change of inspection waiting time (15minutes and 1 hour) by using 4.3 MBq phantom. Results The radioactive concentration per unit mass was increased to 3, 4.3, 5.5, 6.7 MBqs. And when we increased time/bed of each concentration from 1 minute 30 seconds to 30 minutes, we found that the $SUV_{max}$ of hot cylinder acquisition time per bed changed seriously according to each radioactive concentration in up to 18.3 to at least 7.3 from 30 seconds to 2 minutes. On the other side, that displayed changelessly at least 5.6 in up to 8 from 2 minutes 30 seconds to 30 minutes. SNR by radioactive change per unit mass was fixed to up to 0.49 in at least 0.41 in 3 MBqs and accroding as acquisition time per bed increased, rose to up to 0.59, 0.54 in each at least 0.23, 0.39 in 4.3 MBqs and in 5.5 MBqs. It was high to up to 0.59 from 30 seconds in radioactivity concentration 6.7 MBqs, but kept fixed from 0.43 to 0.53. Standard deviation of BKG (Background) was low from 0.38 to 0.06 in 3 MBqs and from 2 minutes 30 seconds after, low from 0.38 to 0 in 4.3 MBqs and 5.5 MBqs from 1 minute 30 seconds after, low from 0.33 to 0.05 in 6.7 MBqs at all section from 30 seconds to 30 minutes. In result that was changed the inspection waiting time to 15 minutes and 1 hour by 4.3 MBq phantoms, $SUV_{max}$ represented each other fixed values from 2 minutes 30 seconds of acquisition time per bed and SNR shown similar values from 1 minute 30 seconds. Conclusion As shown in the above, when we increased radioactive concentration per unit mass by 3, 4.3, 5.5, 6.7 MBqs, the values of $SUV_{max}$ and SNR was kept changelessly each other more than 2 minutes 30 seconds of acquisition time per bed. In the same way, in the change of inspection waiting time (15 minutes and 1 hour), we could find that the values of $SUV_{max}$ and SNR was kept changelessly each other more than 2 minutes 30 seconds of acquisition time per bed. In the result of this NEMA NU2-1994 phantom experiment, we found that the minimum acquisition time per bed was 2 minutes 30 seconds for evaluating values of fixed $SUV_{max}$ and SNR even in change of inserting radioactive concentration. However, this acquisition time can be different according to features and qualities of equipment.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.37-41
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• 2007

The aim of this study is to establish RGP lens care system using RGP lens multi-purpose solution(MPS) and cleaner. Each RGP lens was incubated in Pseudomonas aeruginosa standard strain, and the numbers of P. aeruginosa colony remaining after treatment by using MPS and/or cleaner including surface activating components were estimated. Soaking only in MPS for 30 min reduced the number of P. aeruginosa up to 50%. 95% of P. aeruginosa was eliminated at RGP lenses soaked in MPS for 4 hr, but P. aeruginosa was not detected at RGP lenses soaked for 6 hr. When only cleaner was used for RGP lens care, 70% of P. aeruginosa was eliminated. This result showed that using cleaner had more effective at removing P. aeruginosa than soaking in MPS for 30 min. When soaking in MPS for 30 min after using cleaner reduced the number of P. aeruginosa up to 36% of that which soaking only in MPS for 30 min. This result suggested that using cleaner could be helpful to improve the disinfection efficacy of short time soaking in MPS.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.234-239
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• 2010

The irrigation interval and time for the supply of nutrient and water to the plant is important in the aeroponic system. This study was conducted to investigate the effect of irrigation interval on the growth of Phalaenopsis hybrid seedlings in the aeroponic system. Young bare-root plants (four leaves, 16 g in fresh weight) were used for this experiment. The composition of nutrient solution was, in $me{\cdot}L^{-1}$, 9 N, 3 P, 4 K, 4 Ca and 2 Mg. The electrical conductivity (EC) and pH of nutrient solution used was $1.2\;dS{\cdot}m^{-1}$ and 5.8, respectively. Irrigation intervals were 10, 20, 30, 40, and 50 minute and each irrigation time was 10 minute. The total fresh and dry weight, the number of branched roots, and relative growth rate at the 20 and 30 min. was greater than 10, 40, 50 min. interval. Especially, the fresh weight of roots at 30 min. interval was the highest. Leaf length was the highest at 30 min. interval but there was no difference in leaf width. The amount of water consumed for a month was 0.71 L per plant and it was reduced with increasing irrigation interval. There was no difference in the amount of consumed mineral contents for 15 days except for potassium. Potassium absorbed was the highest at 30 min. irrigation interval. As a result, the optimum irrigation interval was 30 min for the production of Phalaenopsis hybrid seedlings in the aeroponic system.