• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1171-1178
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• 2000

Objective : The purpose of the present study was to determine the appropriate time of clinical intervention by observing and analyzing the changes in the size of infarct, penumbra and cerebral edema and the extend of neurological deficit due to reperfusion damage according to time in a reversible cerebral ischemic model of reperfusing blood flow after inducing ischemia by maintaining middle cerebral artery occlusion for 2 hours(h) in rats. Methods : The rats were divided according to reperfusion time into control group(0 h reperfusion time) and experimental groups(0.5, 1, 2, 3, 4, 5, 6, 12, and 24 h of reperfusion time). Results : Changes in the size of infarction due to reperfusion damage were 0.93, 1.48 and 1.16% at 0.5, 1 and 2 h after reperfusion, respectively, and although a statistical significance was not present compared to 1.35% of the control group, damages increased drastically up to 6 h(6.64%), and the size increased were 6.65 and 6.78% at 12 and 24 h, respectively. Also there was no significant difference after 6 h up to 24 h in the size of infarction. In the areas where infarction occurred, reperfusion damage increased significantly with time in cortex than in subcortex. Accordingly, the size of penumbra area also showed a statistically significant decrease from 2 h up to 6 h after reperfusion, and 6 h after reperfusion, the area almost disappeared, becoming permanent infarction. Thus, reperfusion damage showed a significant increase from 2 h up to 6 h after reperfusion, and became steady thereafter. As for the mean ratio of the extend of cerebral edema, the control group and reperfusion 0.5 h group were 1.073 and 1.081, respectively ; up to 2 h thereafter, the ratio decreased to 1.01 but increased again with time ; and in reperfusion 12 h and reperfusion 24 h, the ratios were 1.070 and 1.075, respectively, showing similar size with that of control group. As for neurological deficit scores, the score of the control group was 2.67, that of reperfusion 2 h was 2, those of reperfusion 3 h and 6 h groups were 3.2 and 3.8, respectively, and those of reperfusion 12 h and 24 h groups were 4.2 and 4.6, respectively. Thus, as for the test results, the neurological deficit increased with time 2 h after reperfusion, and in reperfusion 12 and 24 h groups, almost all the symptoms appeared. Conclusion : As shown in these results, although the changes in the size of infarction due to reperfusion damage did not increase up to 2 h after reperfusion in the experimental groups compared to the control group, damage increased significantly thereafter up to 6 h, and the size remained about the same from 6 h to 24 h after reperfusion, becoming permanent infarction ; thus, the appropriate time of intervention according to the present study is at least 6 h before after maintaining reperfusion, including the time of cerebral artery occlusion.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.523-531
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• 2004

Background : Bronchoscopy in patients on mechanical ventilation is being performed much more frequently. However, there is little data on the changes in physiologic parameters and no established mechanical ventilation protocol during bronchoscopy. A decreasing or the removal of positive end-expiratory pressure (PEEP) during bronchoscopy may precipitate severe hypoxemia and/or derecruitment. Methods : Our standardized mechanical ventilation protocol, without changing the PEEP level, was used during bronchoscopy. The physiological parameters were measured during the bronchoscopic procedure. Results : During bronchoscopy, respiratory acidosis, elevation of peak pressure, elevation of heart rate and auto-PEEP were developed, but were reversible changes. Procedure-related gross barotraumas or other severe complications did not developed. Conclusion : No serious complications developed during bronchoscopy under our standardized mechanical ventilation protocol when the PEEP level remained unchanged. The procedure time should be kept to a minimum to decrease the exposure time to undesirable physiological changes.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.331-338
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• 2014

Cystatins (CSTs) are reversible and competitive inhibitors of C1A cysteine proteases, corresponding to papain-like cathepsins in plants and animals. A viral CST (CpBV-CST1) was identified from a polydnavirus, Cotesia plutellae bracovirus (CpBV). Our previous study indicated that a transient expression of CpBV-CST1 interfered with immune response and development of Plutella xylostella larvae. To directly demonstrate the protein function, this study produced a recombinant CpBV-CST1 protein (rCpBV-CST1) using bacterial expression system to determine its inhibitory activity against cysteine protease and to assess its physiological alteration in insect immune and development. The open reading frame of CpBV-CST1 encodes a polypeptide of 138 amino acids (${\approx}15kDa$). rCpBV-cystatin protein in BL21 STAR (DE3) competent cells containing a recombinant pGEX4T-3:CpBV-CST1 was over-expressed by 0.5 mM IPTG for 4 h. In biological activity assay, the purified rCpBV-CST1 showed a significant inhibition against papain activity. It inhibited a cellular immune response of hemocyte nodule formation in the beet armyworm, Spodoptera exigua. Moreover, its oral administration retarded larval development of the diamondback moth, Plutella xylostella in a dose-dependent manner. These results suggest that CpBV-CST1 may be applied to control insect pest populations.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.78-83
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• 2005

Nanometric crystalline silicon (no-Si) embedded in dielectric medium has been paid attention as an efficient light emitting center for more than a decade. In nc-Si, excitonic electron-hole pairs are considered to attribute to radiative recombination. However the surface defects surrounding no-Si is one of non-radiative decay paths competing with the radiative band edge transition, ultimately which makes the emission efficiency of no-Si very poor. In order to passivate those defects - dangling bonds in the $Si:SiO_2$ interface, hydrogen is usually utilized. The luminescence yield from no-Si is dramatically enhanced by defect termination. However due to relatively high mobility of hydrogen in a matrix, hydrogen-terminated no-Si may no longer sustain the enhancement effect on subsequent thermal processes. Therefore instead of easily reversible hydrogen, phosphorus was introduced by ion implantation, expecting to have the same enhancement effect and to be more resistive against succeeding thermal treatments. Samples were Prepared by 400 keV Si implantation with doses of $1\times10^{17}\;Si/cm^2$ and by multi-energy Phosphorus implantation to make relatively uniform phosphorus concentration in the region where implanted Si ions are distributed. Crystalline silicon was precipitated by annealing at $1,100^{\circ}C$ for 2 hours in Ar environment and subsequent annealing were performed for an hour in Ar at a few temperature stages up to $1,000^{\circ}C$ to show improved thermal resistance. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nc-Si are shown, and the possible mechanisms are discussed as well.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.1
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• pp.53-61
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• 2020

Midazolam is a short-acting benzodiazepine that is widely used in pediatric dental sedation. However, its clinical effectiveness as an intravenous sedative agent in children has not been widely documented. A retrospective study was conducted to evaluate the efficacy and safety of intravenous midazolam and nitrous oxide inhalation sedation in pediatric dental treatment. The subjects were 115 patients (118 cases) who received dental treatment under intravenous midazolam and nitrous oxide inhalation sedation. Demographic factors, general health status, sedation time, midazolam and nitrous oxide dosage, and success rate of sedation were evaluated from electronic medical records. Behavioral management was the main reason of choosing sedation. Mean duration of sedation was 56.7 minutes for surgical treatment, and 74.4 minutes for restorative treatment. The initial dosage of intravenous midazolam was 0.051 ± 0.019 mg/kg. In 34 cases (28.8%), additional midazolam of 0.036 ± 0.057 mg/kg was delivered during the treatment. The concentration of nitrous oxide was maintained between 40% and 50%. The success rate of sedation was 99% (n = 117). In 1 case, laryngospasm occurred and the patient was reversed with benzodiazepine antagonist, flumazenil. Intravenous midazolam sedation with nitrous oxide was shown to be clinically effective for the dental treatment in children, if administered by trained personnel and patients are carefully selected in accordance with guidelines.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.30-38
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• 2010

This study was conducted to determine the effects of vitamin C on the activity of liver function enzymes and electromicrographic changes in white rats treated with aflatoxin $B_1(AFB_1)$ or X-ray and $AFB_1$. Six week-old male Sprague-Dawley rats were randomly divided into five groups: a control group, $AFB_1$ treated group, $AFB_1$ treated group with vitamin C, X-ray and $AFB_1$ co-treated group, X-ray and $AFB_1$ co-treated group with vitamin C. On the first day of the experiment, only one dose of X-rays was exposed to the entire liver at 1,500 cGy. Next, vitamin C was injected at 10 mg/kg body weight by intraperitoneal injection, followed 1 hr later by the administration of 0.4 mg/kg of $AFB_1$ by intraperitoneal injection. These treatments were then administered every three days over a period of 15 days. On the 16th day of treatments, the animals were sacrificed. Analysis of the activity of the liver function enzymes, GOT, ALK phatase and LDH, in the sera of rats revealed that they were somewhat increased by $AFB_1$ treatment, X-ray and $AFB_1$ co-treatment when compared to the control group. Furthermore, the activity of these enzymes decreased in response to administration of vitamin C. Especially, the levels of GOT were remarkably decreased in the $AFB_1$ treated group treated with vitamin C when compared to the group treated with $AFB_1$ alone(p<0.001). Electromicrographic analysis revealed cloudy swelling, necrosis, vesicular degeneration and fat accumulation of hepatocytes in response to treatment with $AFB_1$ or co-treatment with X-ray and $AFB_1$. However, the destruction of hepatic cells was considerably lower in the vitamin C-treated group. These results indicate that vitamin C had ameliorating effects on the hepatic cell damage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.1
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• pp.11-24
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• 1979

To characterize elastic and plastic chilling injury, rice seedlings grown at 28/$16^{\circ}C$ day/night temp. under 20K lux (13hrs.) in a phytotron were subjected to a 11/$6^{\circ}C$, 20K lux condition for 2, 4, 6 or 8 days at 1, 2, 3, 4 or 5th leaf-stage, respectively, followed by further growth under 28/$16^{\circ}C$condition till 30th day after seeding. Japonica variety Jinheung and Chulwon No.1 survived almost 100% without any significant , discoloration and death of leaves due to chilling even under the chilling of 8 days at all seedling ages tested. Tongil and Yushin, varieties from Indica x Japonica cross, showed increasing discoloration of leaves and death of plants with increase in chilling intensity. The longest chilling duration shown seedling death less than 5% was 4, 6, 1, 4, 8 days for Tongil, and 6, 6, 1, 2, 2, days for Yushin at 1, 2, 3, 5th leaf-stage, respectively. The degree of discoloration and death of leaves or suppression of height growth was not explicitly related to seedling death or the dry weight reduction. The degree of seedling death or dry weight reduction could differentiate chilling tolerance of varieties and seedling ages, but somewhat differently. Reduction in dry weight due to chilling occurred even without any visible injury or seedling death. These suggest that both the degree of seedling death and reduction in dry weight should be considered in the test of varieties for chilling tolerance. Combined evaluation of seedling death and dry weight reduction indicated the most susceptible seedling age to chilling injury to be 1 to 2nd leaf-stage for Jinheung, 2 to 3rd leaf-stage for Chulwon No.1, 3rd leaf- stage for Tongil and Yushin, respectively.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.101-112
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• 2004

Chloride($Cl^-$) channels play critical roles in cell homeostasis and its specific functions such as volume regulation, differentiation, secretion, and membrane stabilization. The presence of these channels have been reported in all kinds of cells and even in frog oocytes. These essential role of $Cl^-$­ channels in cell homeostasis possibly play any role in egg homeostasis and in the early stage of development, however, there has been no report about the presence of $Cl^-$­ channel in the mammalian oocyte. This study was performed to elucidate the presence of $Cl^-$­ channels in hamster eggs. When allowing only $Cl^-$­ to pass through the channel of the egg membrane by using impermeant cation such as N-methyl-D-glucamine(NMDG), single channel currents were recorded. These channel currents showed typical long-lasted openings interrupted by rapid flickering. Mean open $time({\tau}o)$ was 43${\pm}$10.14 ms(n=9, at 50 mV). The open probability(Po) was decrease with depolarization. The current-voltage relation showed outward rectification. Outward slop conductance(32${\pm}$5.4 pS, n=22) was steeper than the inward slop conductance(10${\pm}$1.3 pS). Under the condition of symmetrical 140 mM NaCl, single channel currents were reversed at 0 mV(n=4). This reversal potential(Erev) was shifted from 0 mV at 140 mM concentration of internal NaCl(140 mM [Na+]i) to ­9.8${\pm}$0.5 mV(n=4) at 70 mM [Na+]i and 11.5${\pm}$1.9 mV at 280 mM [Na+]i(n=4) respectively, strongly suggesting that these are single $Cl^-$­ channel currents. To examine further whether this channel has pharmacological property of the $Cl^-$­ channel, specific Cl­ channel blockers, IAA-94(Indanyloxyacetic acid-94) and DIDS(4, 4'-diisothiocyan ostillben- 2-2'disulfonic acid) were applied. IAA-94 inhibited the channel current in a dose-dependent manner and revealed a rapid and flickering block. From these electrophysiological and pharmacological resluts, we found the novel $Cl^-$­ channel present in the hamster oocyte membrane. The first identification of $Cl^-$­ channel in the hamster oocyte may give a clue for the further study on the function of $Cl^-$­ channel in the fertilization and cell differentiation.