• Journal of Radiation Protection and Research
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• v.29 no.4
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• pp.243-249
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• 2004

The cytokinesis-block micronucleus (CBMN) assay in combination with FISH technique using chromosome-specific centromeric probes for chromosome 1 and 4 was performed in mitogen stimulated human lymphocytes which were exposed to x-radiation to identify different sensitivity of chromosomes to the induction of micronuclei(MN) and aneuploidy by radiation. The frequencies of micronucleated cytokinesis-blocked(MNCB) cells and MN in binucleated lymphocytes(BN) increased with the increase in radiation dose. A significant induction of aneuploidy of chromosome 1 and 4 were found. The frequency of aneuploidy of chromosome 1 and 4 in the control were 9 per 2,000 BN cells and this increased to 47 and 71 following irradiation at a dose of 1 and 2 Gy, respectively. The induction of aneuploidy of chromosome 1 was higher than that of chromosome 4. The frequency of aneuploid BN cells with MN exhibiting positive centromere signal for either chromosome 1 and/or 4 increased in a dose dependent manner, and that for chromosome 1 is higher than that for chromosome 4. Among the total induced MN in irradiated lymphocytes, smaller proportion of MN exhibit centromeric signal of chromosome indicating that radiation-induced MN are mainly originated from chromosomal breakage rather than chromosomal non-disjunction. These results suggest that x-radiation can induce aneuploidy and supports the finding that chromosome vary in their sensitivity to aneuploidy induction by x-irradiation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.825-829
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• 2011

We performed a dynamic characterization of passive flow-rate regulators, which compensate for inlet pressure variation and maintain a constant flow rate for precise liquid control in microfluidic systems. To measure the flow rate for a short time, much less than the period of the dynamic inlet pressure, we use the particle image velocimetry (PIV) method. DI water containing fluorescent beads with a $0.7-{\mu}m$ diameter was supplied to the flow-rate regulators, and two successive images of the particles were taken by a pulse laser and a fluorescent microscope to measure the flow velocity. For a dynamic inlet pressure of frequency 60 Hz, the flow velocity was constant with an average of 0.194 ${\pm}$ 0.014 m/s as the inlet pressure varied between 20 kPa to 50 kPa. The flow-rate regulators provided a constant flow rate of $5.82{\pm}0.29\;{\mu}l/s$ in the frequency range of the inlet pressure from 1 Hz to 60 Hz.

• Herbal Formula Science
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• v.30 no.2
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• pp.37-44
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• 2022

Objectives : The purpose of this study was to examine the effects of Alisma canaliculatum Extract (ACE) on pacemaker potentials of small and large intestinal interstitial Cells of Cajal (ICC) in mice. Methods : We used enzymatic digestions to dissociate the ICC in the small and large intestine in mice. The whole-cell patch-clamp method was used to record pacemaker potentials in ICC. Results : 1. The ICC generated the pacemaker potentials in small intestine in mice. ACE (0.1-1mg/ml) induced membrane depolarization and decreased frequency with concentration-dependent manners. 2. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, a nonselective cation channel blocker, stopped the small intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE had no effects on the membrane depolarizations in small intestinal ICC. 3. The ICC generated the pacemaker potentials in large intestine in mice. Membrane depolarization appears regularly in the small intestine, but irregularly in the large intestine. ACE induced membrane depolarization (0.1-1mg/ml) and increased frequency (0.1-0.5mg/ml). 4. Pretreatment with a Ca²⁺ free solution, Na⁺ 5 mM solution or 2-APB, stopped the large intestinal ICC pacemaker potentials. In the case of Ca²⁺-free solution, Na⁺ 5 mM solution or 2-APB, ACE depolarized the membrane depolarizations in large intestinal ICC. 5. In mice, intestinal transit rate (ITR) values were dose-dependently decreased by the intragastric administration of ACE. Conclusions : These results suggest that ACE can regulate the pacemaker activity of ICC and the reaction by ACE is different from the small and large intestinal ICC, and the control of the intestinal motion by ACE may be caused by many complex processes.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.297-305
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• 1998

This study used in vivo intracellular recording in rat hippocampus to evaluate the effect of lidocaine and MK-801 on the membrane properties and the synaptic responses of individual neurons to electrical stimulation of the commissural pathway. Cells in control group typically fired in a tonic discharge mode with an average firing frequency of $2.4{\pm}0.9$ Hz. Neuron in MK-801 treated group (0.2 mg/kg, i.p.) had an average input resistance of $3.28{\pm}5.7\;M{\Omega}$ and a membrane time constant of $7.4{\pm}1.8$ ms. These neurons exhibited $2.4{\pm}0.2$ ms spike durations, which were similar to the average spike duration recorded in the neurons of the control group. Slightly less than half of these neurons were firing spontaneously with an average discharge rate of $2.4{\pm}1.1$ Hz. The average peak amplitude of the AHP following the spikes in these groups was $7.4{\pm}0.6$ mV with respect to the resting membrane potential. Cells in MK-801 and lidocaine treated group (5 mg/kg, i.c.v.) had an average input resistance of $3.45{\pm}6.0\;M{\Omega}$ and an average time constant of $8.0{\pm}1.4$ ms. The cells were firing spontaneously at an average discharge rate of $0.6{\pm}0.4$ Hz. Upon depolarization of the membrane by 0.8 nA for 400 ms, all of the tested cells exhibited accommodation of spike discharge. The most common synaptic response contained an EPSP followed by early-IPSP and late-IPSP. Analysis of the voltage dependence revealed that the early-IPSP and late-IPSP were putative $Cl^--and\;K^+-dependent$, respectively. Systemic injection of the NMDA receptor blocker, MK-801, did not block synaptic responses to the stimulation of the commissural pathway. No significant modifications of EPSP, early-IPSP, or late-IPSP components were detected in the MK-801 and/or lidocaine treated group. These results suggest that MK-801 and lidocaine manifest their CNS effects through firing pattern of hippocampal pyramidal cells and neural network pattern by changing the synaptic efficacy and cellular membrane properties.

• Journal of the Korean Applied Science and Technology
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• v.38 no.4
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• pp.1056-1069
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• 2021

This study is a similar experimental study before and after the inequality control group to investigate the effect of PETTLEP model-based image training on fundamental nursing practice education on the confidence and competence ability of core basic nursing skills, and participation in autonomous practice. Data were collected by randomly assigning 74 students who understood the purpose of the study and voluntarily agreed to participate in the study among second-year students of the Department of Nursing at U University located in K Province, randomly assigned to an experimental group and a control group. For the collected data, frequency and percentage were used for general characteristics of subjects using SPSS Statistics 23.0 program, skewness and kurtosis were used for normality test, and the dependent variable test for measuring the effect of experimental treatment was analyzed by paired t-test. As a result of the study, PETTLEP model-based image training showed confidence in core basic nursing skills(t=4.18, p<.001) and competence (knowledge(t=2.241, p=.032), nursing skills(t=8.402, p<.001)), there were statistically significant differences in self-practice participation(t=6.822, p<.001). Based on the results of this study, the PETTLEP model-based image training provided Based on the results of this study, it was confirmed that PETTLEP model-based image training can be a teaching and learning method applicable to basic nursing education. In addition, PETTLEP model-based image training is expected to be utilized as a learning method to improve the competence of core basic nursing skills, which are recognized as difficult due to their high level of difficulty.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.735-747
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• 2023

In recent times, the sharp increase in extreme flood damages due to climate change has posed a challenge to effectively address flood-related issues solely relying on conventional flood management infrastructure. In response to this problem, this study aims to consider the effectiveness of nature-based flood management approaches, specifically levee retreat and relocation. To achieve this, we utilized a 1D numerical model, HEC-RAS, to analyze the flood reduction effects concerning floodwater levels, flow velocities, and time-dependent responses to a 100-year frequency flood event. The analysis results revealed that the effect of creating a flood buffer zone of the nature-based solution extends from upstream to downstream, reducing flood water levels by up to 30 cm. The selection of the flow roughness coefficient in consideration of the nature-based flood buffer space creation characteristics should be based on precise criteria and scientific evidence because it is sensitive to the flood control effect analysis results. Notably, floodwater levels increased in some expanded floodplain sections, and the reduction in flow velocities varied depending on the ratio of the expanded cross-sectional area. In conclusion, levee retreat and floodplain expansion are viable nature-based alternatives for effective flood management. However, a comprehensive design approach is essential considering flood control effects, flow velocity reduction, and the timing of peak water levels. This study offers insights into addressing the challenges of climate-induced extreme flooding and advancing flood management strategies.

• Journal of the Korean Home Economics Association
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• v.27 no.2
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• pp.133-148
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• 1989

This study attempts of analyze empirically the living status of the elderly in Korea by finding out the problems of it in the family and by clarifying the influences of the family environmental variables and the values on the adjustment of the aged. To carryout the aim of this study, the causes and the patterns of the problems for the aged had been found out through the review of literature. Based on them the questionnaire was prepared including the questions of the values, family environmental vriables as well as the degree of satisfaction of thier liver and the extent of life interchange. The former variables were taken as independent and the latter were taken as dependent variables, so that the relationship between the two variables could be exemplified. The 400 aged over 60 living in Seoul and the other cities were selected through the purposive sampling and interviewed. The answers of the 376 respondents, 94% of the sample, were analyzed for this study. The following results have been found out through the various statistical analysis such as frequency distribution, chi-square test, pearson's correlation, analysis of variance and cluster analysis. At first, the results from the examination of the frequency distribution regarding the living status of the aged are; I) sixteen percent of the respondents living with their married offspring were receiving economical support, though they pointed out the problems of the extended family are the inconveniences with their children (60%) and simpleness (20%) of their livers. It seems that the aged in Korea are poor and have negative opinion on the relationship with their offspring even if they live in the same house. Secondly, it has been found out that the family environmental variables, especially such as sex, occupation, residence, education, level, living ability and the family type, play and important role not only on the degree of satisfaction of their liver but also on the extent of interchange of their lives. However, the variables such as religion and whether the spouse is alive or not do not play and important role. Thirdly, the reported main reasons of their delightness were healthy life (1.87%), the well-being of their offspring (2.08%), the spouse's long life (3.38%), religious activity (5.05%), the hobby activity (4.31%) and the participation in the social activity (5.05%). While, they mainly concern about the illness (1.98%), offspring (2.00%), econmic difficulties (3.39%), inharmonious home (3.81%) and the despicable treatment (3.81%). The respondents wer classified into two groups, they are dependent and independent, using cluster analysis. Health, social activity, offspiring, religion, couple's long life among the factors which lead them to be delighted were turned out to be statistically signhificant at 0.01 significance level between the two groups. As far as their worrisome matters are concerned, health and economic difficulties were significantly different between the two groups. Fourthly, regarding the life interchange, it has been proved that there is a statistically significant differences betwwen the two groups in the economic and the emotional satisfaction, help for ordinary life, status in the family, subjective and objective relationship with offspring, but not in economic dependency and the activity status. Fifthly, it has been noted that there is a high correlation between the degree of life's satisfaction and the extent of life interchange. On the basis of the results mentioned above, it could be concluded taht; i) The majority of the aged in Korea are not economically active, and thus they live with their married offspring even of they have a negative opinion on the subjective relationship with them. This can be pointed out as the main problem of the aged and thus it needs to be studied further. ii) the environmental variables such as age, sex education level, family type and occuption (which can not be changed by their effrot) turned out to give an important effect on the extent of the life interchange among the aged. iii) The respondents who are identified as independent group have a higher degree of life satisfaction and family status than the group identified as defendent. Thus, it can be inferred that it is possible for them to adjust their life by making an effort to modify themselves. iv) The high correlation between the extent of life interchange and the degree of life satisfaction indicates that the elderly themselves can adjust in order to obtain the higher degree of life satisfaction. Therefore, the following suggestions are derived from this study. First of all, the aged should try to be psychologically independent. Second, they need to control themselves in order to achieve self-assurance. Third, the community have to prepare a program of self-development for the aged. Fourth, the social welfare policy that can solve the problem of illness and poverty of the elderly should be introduced, so that their minimum requirements can be satisfied.

• Journal of agricultural medicine and community health
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• v.34 no.1
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• pp.87-100
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• 2009

Objectives: This study was conducted to suggest the way to improve the tobacco control program of public health centers in Korea. Methods: A survey with a self-administered questionnaire was conducted among 246 persons in charge of tobacco control work in public health centers nationwide in December, 2006. Frequency analysis was performed with a final sample of 212 respondents with SPSS 12.0 for Windows. Results: The duration of engagement in tobacco control work was less than 3 years among 86.7% of respondents, and 87.3% of respondents had other duties besides tobacco control. Almost all public health centers conducted a campaign with posters or leaflets, and smoking prevention education among adolescents. The actual priority for programs was based on the community diagnosis in only 33.5% of the cases. Only 1.9% of respondents complained lack of budget, on the other hand, 44.7% of respondents appealed insufficient number of personnel. The route of knowledge and skill was largely dependent on self-learning or information from colleague. Collaboration with other related department was done well in 39.5% of the cases. The majority of respondents was satisfied with the general support from central government. Conclusions: To improve the tobacco control program of public health centers, it is needed the reinforcement of capacity and specialty among personnel, priority setting and performance of programs based on the scientific evidence, induction of community participation, utilization of community human resources, development of education and training course for practical skill, effective networking among departments.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.188.2-188.2
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• 2015

The presence of the conduction interface in epitaxial $LaAlO_3/SrTiO_3$ thin films has opened up challenging applications which can be expanded to next-generation nano-electronics. The metallic conduction path is associated with two adjacent insulating materials. Such device structure is applicable to frequency-dependent impedance spectroscopy. Impedance spectroscopy allows for simultaneous measurement of resistivity and dielectric constants, systematic identification of the underlying electrical origins, and the estimation of the electrical homogeneity in the corresponding electrical origins. Such unique capability is combined with the intentional control on the interface composition composed of $SrTiO_3$ and $CaTiO_3$, which can be denoted by $SrxCa1-_xTiO_3$. The underlying $Sr_xCa1-_xTiO_3$ interface was deposited using pulsed-laser deposition, followed by the epitaxial $LaAlO_3$ thin films. The platinum electrodes were constructed using metal shadow masks, in order to accommodate 2-point electrode configuration. Impedance spectroscopy was performed as the function of the relative ratio of Sr to Ca. The respective impedance spectra were analyzed in terms of the equivalent circuit models. Furthermore, the impedance spectra were monitored as a function of temperature. The ac-based characterization in the 2-dimensional conduction path supplements the dc-based electrical analysis. The artificial manipulation of the interface composition will be discussed towards the electrical application of 2-dimensional materials to the semiconductor devices in replacement for the current Si-based devices.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.1-10
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• 1990

The protective effect of sodium selenite($Na_2SeO_3$) against the cytogenetic toxicity of heavy metals was investigated on human whole-blood cultures in relation to induction of sister chromatid exchange (SCE) in secondary metaphase chromosome. Methylmercury chloride($CH_3HgCl$), cadmium chloride($CdCl_2$), potassium dichromate($K_2Cr_2O_7$), and sodium selenite caused to the typically dose-dependent increase in sister chromatid exchanges (SCEs) by the concentrations ranging from $0.3{\mu}M\;to\;10{mu}M$. However, the inductions of sister chromatid exchanges by methylmercury chloride or cadmium chloride were inhibited by the simultaneous addition of sodium selenite $1.2{mu}M$. The frequencies of SCE were decreased to the level of control in the molar ratios as 2:1, 1:1, 1:2, and 1:4 of selenium selenite vs. methylmercury chloride, and as 1:1 and 1:2 of selenium selenite vs. cadmium chloride, while the frequencies of SCE induced by potassium dichromate were not changed by the addition of sodium selenite in culture condition. Mitotic indices were decreased in the higher concentrations of chemicals and not significantly changed by the simultaneous addition of sodium selenite to the culture condition containing each chemicals.