• Educational Technology International
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• 제11권1호
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• pp.27-46
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• 2010

The purpose of this paper is to apply the newly developed SICAT teaching and learning model to the actual scene of teaching and learning and draw a point of discussion for utilizing teaching and learning model, by uncovering the satisfaction of students and the inhibiting/facilitating elements when using the model. SICAT(Scientific Inquiry and Creative Activity with Technology; from here on SICAT), a teaching and learning model custom-built for engineering education, was developed, as more and more people paid attention to the demand for creative engineers. It was developed from the basis of PBL(Problem Based Learning), includes three sub-types which can be applied to the actual theory, design, and experimentation fields within engineering education. The three sub-types, which are ARDA(Analysis-Reasoning Activity & Discussion-Argumentation Activity), CoCD (Collaboration Activity & Capstone Design Activity), and ReSh(Reflection Activity & Sharing Activity), respectively support deductive and argumentation activities, creative design and collaboration activities, and retrospection and sharing activities. However, no research has been conducted to investigate whether or not there are inhibiting or facilitating elements in the application procedure, or what the rate of satisfaction for students is, when applying the SICAT model, which was newly developed to innovate existing engineering education, to the actual site of teaching and learning. Therefore, this research applied three types of SICAT teaching and learning models to the theory, design, and experimentation classes at the department of materials science and engineering at Hanyang University for eight weeks. After application, the students, teachers and tutors were surveyed and interviewed, and then the results analyzed in order to uncover inhibiting/facilitating elements and the rate of satisfaction. The satisfaction rate of students from the SICAT teaching and learning model was 3.78(in a perfect score of 5: The A type-3.65, The C type-3.80, The R type-3.90), and inhibiting/facilitating elements were drawn from the aspects of learning activities, support system. In conclusion, they can be contributed for implications of SICAT teaching and learning model universal use at engineering education in University.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1135-1139
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• 1997

Major factors inhibiting nonenzymatic browning in stored ginger paste were investigated using aqueous model systems with temperature, water activity, pH and sulfur compounds. Browning index and total gingerols were measured during storage. The rate of nonenzymatic browning reactions showed a strong depencence on temperature and pH and a negligible influence on water activity. It was also reduced by the addition of 0.04% N-actyl-L-cysteine(NAcCys), effectively. Activation energies for aqueous ginger model systems with and without 0.04% NAcCys were 29.0 and 25.8kcal/mole, respectively.

• Corrosion Science and Technology
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• 제20권3호
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• pp.129-142
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• 2021

Effects of corrosion inhibitors (i.e., sodium nitrite, sodium hexametaphosphate, trimethylamine (TEA), sugar, and urea) on the corrosion resistance of carbon steel in CaCl₂ solution were investigated. The test solution was designed with response surface methodology of design of experiments (DOE) in the range of 0 ~ 50 ppm for NaNO₂, 0 ~ 200 ppm for (NaPO₃)₆, 0 ~ 2000 ppm for TEA, 0 ~ 3000 ppm for sugar, 0 ~ 200 ppm for urea with 3 wt% CaCl₂. The corrosion potential and the corrosion rate were measured with potentiodynamic polarization tests and analyzed statistically to find main effects of inhibitor concentrations and interactions between them. As a result, hexametaphosphate was the most effective compound in reducing the corrosion rate. Sugar also reduced the corrosion rate significantly possibly because it covered the surface effectively with a high molecular weight. The inhibiting action of sugar was found to be enhanced by adding trimethylamine into the solution. Nevertheless, trimethylamine did not appear to be effective in inhibiting corrosion by itself. However, urea and sodium nitrite showed almost no inhibition on corrosion resistance of steel.

• 대한소아치과학회지
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• 제28권4호
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• pp.583-592
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• 2001

치태 억제효과가 있는 것으로 알려진 Lactococcus lactis 1370으로 제조한 양치용액이 실제 소아들의 구강내에서 치태의 형성을 억제하는지 여부와 이들 균주의 시간경과에 따른 구강내 잔류율을 알아보고자 소아 30명을 대상으로 위양치액 (Lactobacillus casei)과 유산균 양치액 (Lactococcus lactis 1370)으로 양치하도록 한 뒤 시간경과에 따른 치태지수, 치태부착면적을, 그리고 Lactococcus lactis 1370의 생균수를 count하여 다음과 같은 결과를 얻었다. 1. 대조군과 실험군에서 24시간후 치태지수는 각각 평균 2.43과 2.06으로 양치에 의해 치태지수는 평균 0.37 감소하였으며 치태형성억제율은 약 15%로 유의한 감소를 보였다 (P<0.05). 2. 48시간 후 치태지수는 대조군과 실험군에서 각각 평균 2.95와 2.17로 양치에 의해 치태지수는 평균 0.78 감소하였으며 치태형성 억제율은 약 26%로 24시간후에 비해 좀더 많은 감소를 보였다(P<0.05). 3. 대조군과 실험군에서 24시간후 치태부착면적율은 각각 평균 21.2%와 15.6%로 양치에 의해 치태부착면적율은 평균 5.63% 감소하였으며 치태형성억제율은 약 26%로 유의한 감소를 보였다(P<0.05). 4. 48시간후 치태부착면적율은 대조군과 실험군에서 각각 평균 33%와 17.8%로 양치에 의해 치태부착면적율은 평균 15.1% 감소하였으며 치태형성 억제율은 약 46%로 24시간 후에 비해 좀 더 많은 감소를 보였다(P<0.05). 5. 양치후 시간에 따른 구강내 생균수를 count한 결과 1시간 이후까지는 급격한 감소를, 3시간 후에는 약간의 감소를 보였으며 3시간부터 6시간 사이에는 약간의 증가추세를 보였다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 1999년도 춘계학술발표논문집 논문집
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• pp.243-248
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• 1999

There is substantial evidence that anatomical connections and functional interactions exist between vestibular and autonomic systems. Heart rate variability (HRV) including mean, standard deviation, coefficient of variation (CV), power spectrum was analyzed for evaluation of the physiological role of the vestibular system on control of heart rate in rabbits. In anesthetized rabbits, electrical stimulation of the vagus nerve decreased heart rate and decreased LF/HF by increasing HF. On the cervical sympathetic nerve increased heart rate and increased LF/HF by increasing LF. Atropine, cholinergic blocker, increased heart rate and increased LF/HF by reducing HF, and propranolol, ${\beta}$-adrenergic blocker, decreased heart rate and decreased LF/HF by reducing LF> In unanesthetized rabbits, stimulation of the vestibular system induced by rotation or caloric increased heart rate and increased LF/HF by increasing LF> Also electrical stimulation of the vestibular nerve produced the same of effects as rotation or caloric in anesthetized rabbits. These results suggest that Stimulation of the vestibular system increased heart rate not by inhibiting the parasympathetic nerve but by activating the sympathetic nerve.

• 대한소아치과학회지
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• 제11권1호
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• pp.151-157
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• 1984

The purpose of this study was to compare the growth-inhibiting effect of sodium fluoride and stannous fluoride on a cariogenic strain of Streptococcus mutans exposed to the different concentration of $SnF_2$ and NaF The result were as follows: 1. The growth rate of the Streptococcus mutans was unaffected by 75 ppmF, slowed by 150 ppmF, and immediately arrested by 300 or 600 ppmF where increments of NaF were added to actively growing 12-hour broth culture. 2. $SnF_2$ slowed the growth rate at 75 ppmF, was to bactericidal initially at 150 and 300 ppmF, and was to totally bactercidal at 600 ppmF. 3. $SnF_2$ has been shown to be more effective than NaF in inhibiting the growth activity of Streptococcus mutans. 4. The inhibitory effect of fluoride compounds on the growth of Streptococcus mutans was increased in the decreased pH at concentration of 600 ppmF.

• 대한의생명과학회지
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• 제18권4호
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• pp.420-427
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• 2012

Sprague-Dawley (SD) rats were orally administered with NG-nitro-L-arginine methyl ester (L-NAME), which inhibits or blocks the production of nitric oxide from L-arginine in vascular endothelial cells and vessel tissue. We examined the effects of nitric oxide on some physiological changes such as blood pressure and heart rate, and confirms the apoptosis induced by the suppressed nitric oxide activity in the kidney. This study was performed to investigate correlation between the activities of nitric oxide and apoptosis by immunohistochemical changes of apoptotic control proteins with regulated chronic inhibition of nitric oxide. In the kidney from L-NAME-treated group, immunohistochemical reaction to the antigens of apoptosis inhibiting proteins such as bcl-2 and bcl-xL, exhibited a time-dependent reduction. The expression of apoptosis-inhibiting proteins such as bax and p53 increased expression in proportion to the duration of treatment. The most sensitive apoptosis regulating proteins to L-NAME were p53 in stimulation and bcl-2 in inhibition, respectively.

• Journal of Plant Biology
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• 제25권1호
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• pp.21-36
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• 1982

The activity of photosystem II in isolated chloroplast form the leaves of Sedum sarmentosum was measured. The photoreduction rate of DCPIP by photosystem II showed the circadian rhythm with a peak at near midday sample for a continuing fine day and at near afternoon between nidday and sunset sample for a continuing cloudy day in summer. The optimum light intensity of photoreduction by photosystem II in the chloroplast preparation was about 5~9$\times$$10^4$ lux. The saturated light intensity was over 9$\times$$10^1$lux. Photosystem II activity was inhibited by even the lowest concentration of lead. When Pi and ATP of the same concentration as Pb were added to the reaction mixture containing Tris buffer lacking of Pi prior to Pb incubation, photosystem II activity was protected from Pb-inhibiting effect by the pretreament of Pi and ATP. It was assumed that Pb inhibiiton was probably due to one, P-depriving by the precipitates of $Pb_3$ $($Pb_4$)_2$ in the reaction mixture and the other, partially Pb-combing with Pi groups of the active site of photosystem II.

• 대한약리학회지
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• 제11권2호
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• pp.1-8
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• 1975

This study was carried out to observe the effect of testosterone on carbonic anhydrase inhibiting action of acetazolamide. Carbonic anhydrase activities in the kidneys of mice were measured by Philpot and Philpot method(1936) at 30, 90 and 150 minutes after intravenous administration of saline(0.5 ml/10 g) or acetazolamide (0.25 mg/10 g) in mice pretreated with testosterone (0.1 mg/10 g). The changes in volume and pH of urine as well as those in urinary electrolytes, such as $Na^+,\;K^+\;and\;Cl^-$ were measured at 15 minutes interval for 150 minutes in the rabbit pretreated with double administrations of testosterone(10 mg/kg), 1 hour and 18 hours, prior to the administration of acetazolamide (10 mg/kg). The results were as follows: 1. Carbonic anhydrase activities in the kidneys of mice of testosterone-pretreated groups were significantly higher than those of acetazolamide-treated group at 30 minutes. No significant changes of carbonic anhydrase activities were observed in testosterone-pretreated groups compared with saline-treated groups. 2. Combined administrations of acetazolamide and testosterone exhibited higher carbonic anhydrase activity than those group of acetazolamide alone in the kidney of mice through observed period of 150 minutes. 3. There were no significant changes in the excretion rate of urine and urinary electrolytes in the group of rabbits with testosterone administerone alone. Urine volume as well as $Na^+\;and\;Cl^-$ excretion rates in the combined treated group of acetazolamide and testosterone were significantly lower than that of acetazolamide group throughout experimental period except 15 minutes after drug administration at the time transient increase was shown. 4. Generally lower $K^+$ excretion rate was observed in the combined treated group of acetazolamide and testosterone compared with the single acetazolamide-treated group and the testosterone-pretreated group shows lowest excretion rate of potassium.

• Asian Pacific Journal of Cancer Prevention
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• 제16권10호
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• pp.4369-4376
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• 2015

Background: To investigate in-vitro antagonistic effect of low-dose liquiritigenin on gemcitabine-induced capillary leak syndrome (CLS) in pancreatic adenocarcinoma via inhibiting reactive oxygen species (ROS)-mediated signalling pathways. Materials and Methods: Human pancreatic adenocarcinoma Panc-1 cells and human umbilical vein endothelial cells (HUVECs) were pre-treated using low-dose liquiritigenin for 24 h, then added into gemcitabine and incubated for 48 h. Cell viability, apoptosis rate and ROS levels of Panc-1 cells and HUVECs were respectively detected through methylthiazolyldiphenyl-tetrazoliumbromide (MTT) and flow cytometry. For HUVECs, transendothelial electrical resistance (TEER) and transcellular and paracellular leak were measured using transwell assays, then poly (ADP-ribose) polymerase 1 (PARP-1) and metal matrix proteinase-9 (MMP9) activity were assayed via kits, mRNA expressions of p53 and Rac-1 were determined through quantitative polymerase chain reaction (qPCR); The expressions of intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and PARP-1 were measured via western blotting. Results: Low-dose liquiritigenin exerted no effect on gemcitabine-induced changes of cell viability, apoptosis rate and ROS levels in Panc-1 cells, but for HUVECs, liquiritigenin ($3{\mu}M$) could remarkably elevate gemcitabine-induced decrease of cell viability, transepithelial electrical resistance (TEER), pro-MMP9 level and expression of ICAM-1 and VCAM-1 (p<0.01). Meanwhile, it could also significantly decrease gemcitabine-induced increase of transcellular and paracellular leak, ROS level, PARP-1 activity, Act-MMP9 level, mRNA expressions of p53 and Rac-1, expression of PARP-1 and apoptosis rate (p<0.01). Conclusions: Low-dose liquiritigenin exerts an antagonistic effect on gemcitabine-induced leak across HUVECs via inhibiting ROS-mediated signalling pathways, but without affecting gemcitabine-induced Panc-1 cell apoptosis. Therefore, low-dose liquiritigenin might be beneficial to prevent the occurrence of gemcitabine-induced CLS in pancreatic adenocarcinoma.