• ETRI Journal
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• v.23 no.4
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• pp.177-189
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• 2001

Multicarrier DS-CDMA is an effective approach to combat fading and various kinds of interference. In this paper, we present an overlapped multicarrier DS-CDMA system, wherein each of the rate 1/M convolutionally-encoded symbols is also repetition coded and transmitted using overlapped multicarriers. However, since the frequency spectrums of successive carriers are allowed to overlap, the transmission bandwidth is more efficiently utilized. The effect of the overlapping percentage between successive carriers of a multicarrier DS-CDMA system on the performance is investigated to determine the overlapping percentage showing the best performance. We suggest two methods for sub-band overlapping variation. One is to allow variation of sub-band overlapping percentage when the total number of subcarriers is fixed. The other is to increase the number of sub-bands (the number of repetitions R) with fixed sub-band bandwidth. Given a total number of subcarriers MR, we show that the BER variation is highly dependent on the roll-off factor ${\beta}$ of a raised-cosine chip wave-shaping filter irrespective of convolutional encoding rate 1/M and repetition coding rate 1/R. We also analyze the possibility of reduction in total multi-user interference by considering the variation of both the roll-off factor ($0<{\beta}{\leq}1$) and the sub-band overlapping factor ($0<{\lambda}{\leq}2$), and show that the proposed system may outperform the multicarrier DS-CDMA system in [3].

• Biomedical Science Letters
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• v.24 no.2
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• pp.130-133
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• 2018

The aim of this study was to evaluate the protective function of fisetin, a natural flavonoid in zebrafish heart for the treatment of myocardial infarction in coronary and ischemic heart disease. For this purpose, we induced oxidative stress zebrafish (Danio rerio)-Tg (cmlc2: egfp) by $H_2O_2$ and then administered fisetin, the protective effect of fisetin was determined by measuring the heart rate following fisetin administration. After testing the toxicity of fisetin, we found that the heartt increased in a concentration-dependent manner, however there was no difference between the heart rates of embryos and adults. The improved heart rate demonstrated the cardioprotective effect of fisetin. The result showed that fisetin, at concentration of 3and $5{\mu}M$, significantly increased heart rate compared with the heart with $H_2O_2$ alone. This indicates that fisetin plays an important role in the prevention of heart damage and treatment of cardiovascular diseases caused by oxidative stress due to ischemia / reperfusion.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.2
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• pp.196-206
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• 1995

Experimental investigations on heat and mass transfer characteristics in a vertical tube absorber have been carried out. Three different copper tubes with a length of 1.5m have been tested using LiBr solution and LiBr-$CaCl_2$ solution. The effects of solution flow rate, cooling water temperature, solution inlet temperature and evaporation temperature have been investigated in detail. It is found that heat transfer coefficient increases gradually with the increase of solution flow rate, but decreases rapidly for the flow rates less than 0.02kg/ms. The grooved tube generally shows better heat transfer performances than the smooth tube. LiBr solution shows almost no absorption capability for the cooling water temperatures over $40^{\circ}C$. LiBr-$CaCl_2$ gives less decreasing rate in absorption capability at these temperatures and the heat transfer coefficient becomes less dependent on the types of tubes in use. Considering heat and mass transfer rates, LiBr-$CaCl_2$ solution is found to be more suitable than LiBr solution for air cooled absorber, which operates at higher temperature than water cooled absorber.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.639-645
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• 1997

The purpose of the present study is to determine the role of muscarinic cholinergic receptors of posterior hypothalamus in the central blood pressure regulation when respiration is controlled. In anesthetized and artificially ventilated rats, vasodepressor response was evoked by injection of L-glutamate(10 nmol) neuroexcitatory amino acid into the posterior hypothalamic area. The injection of $carbachol(0.5{\sim}8\;nmol)$ into the same area induced dose-dependent vasodepressor and bradycardic responses. Pretreatment with atropine(4 nmol) completely blocked the vasodepressor response to carbachol(2 nmol). In contrast, in spontaneously breathing rats, the injection of carbachol(8 nmol) into the posterior hypothalamic area induced the vasopressor and tachycardic responses. These results suggest that the muscarinic cholinergic receptors in the posterior hypothalamic area primarily play an inhibitory role in the central regulation of blood pressure and heart rate.

• Culinary science and hospitality research
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• v.12 no.2 s.29
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• pp.1-17
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• 2006

This study is to develop a viable measurement tool of crowdedness in restaurants. First, to measure customer’s awareness of crowdedness related to each different environmental factor in a restaurant, 49 factors of crowdedness awareness were selected based on the previous studies and then properties of each factor affecting customer’s satisfaction for crowdedness were analyzed. To analyze effects of each factor upon the satisfaction rate, a Multiple Regression Analysis was conducted with the crowdedness awareness as an independent variable and satisfaction of crowdedness as a dependent variable. The results showed that when an analysis of the environmental factors in the crowdedness awareness was conducted in an effort to develop a measurement tool of crowdedness awareness in restaurants, that would be fit for the domestic food service market, based upon 49 factors of restaurant environment. Focusing on expectation and satisfaction rate, it was found that rating the satisfaction level would be a much more effective tool to measure crowdedness awareness because satisfaction rate appeared to be more closely related to the awareness than the results obtained from the Multiple Regression Analysis with a difference between expectation and satisfaction scores as an independent variable.

• Korean Journal of Health Education and Promotion
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• v.23 no.3
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• pp.85-97
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• 2006

Objectives: This study was done for the purpose of revitalization of the health improvement project by looking into major influence factors on the health examination of local residents in a city area. Methods: The research data was collected using a survey of the local residents in Wonju-City, Gangwondo. The survey was held between Oct. 4th to Oct. 15th, 2004. And, it was done as a household interview survey. The independent variables used were socio-demographic characteristics, health status, health concern, and health behaviors. The dependent variable was whether or not the respondent did take a cancer screening test. Results: In case of men, the execution rate of cancer screening was higher for those who had spouses, who were having no experience of a disease, who drank, and who did exercise. In the case of women, the execution rate of cancer screening was higher in the cases who had spouses, who had high income levels, and who were making an effort for their health. Conclusion: To raise the execution rate of health examination, more research on the major factor of cancer screening is necessary.

• KSBB Journal
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• v.26 no.3
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• pp.206-210
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• 2011

The growth effect of Nannochloropsis oculata (N.oculata), unicellular microalgae, by alginate was investigated. Alginate was depolymerized with sulfuric acid ($H_2SO_4$) and heat ($121^{\circ}C$), simultaneously. Addition of 0.75% alginate oligomer depolymerized with 0.2 N $H_2SO_4$ showed the maximum yield and the growth rate of N. oculata. Chlorophyll content and reducing sugar was increased by alginate oligomer in a dose-dependent manner. Alginate oligomer promoted the growth of N. oculata, whereas the original alginate polysaccharides had no significant effect. Laminaria japonica (L. japonica) extract containing high level of alginate was also increased growth rate and chlorophyll content. $CO_2$ supply addition to L. japonica extract showed no change the growth rate, although addition to alginate oligomer showed prominently increased. N. oculata could use more saccharides in presence of $CO_2$ according to reducing sugar determination. From these results, it is useful to establish optimal condition for high cell density cultivation of N. oculata.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.206-211
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• 2017

The effect of temperature on the rate of systemic infection of potatoes (Solanum tuberosum L. cv. Chu-Baek) by Potato virus Y (PVY) was studied in growth chambers. Systemic infection of PVY was observed only within the temperature range of $16^{\circ}C$ to $32^{\circ}C$. Within this temperature range, the time required for a plant to become infected systemically decreased from 14 days at $20^{\circ}C$ to 5.7 days at $28^{\circ}C$. The estimated lower thermal threshold was $15.6^{\circ}C$ and the thermal constant was 65.6 degree days. A systemic infection model was constructed based on experimental data, using the infection rate (Lactin-2 model) and the infection distribution (three-parameter Weibull function) models, which accurately described the completion rate curves to systemic infection and the cumulative distributions obtained in the PVY-potato system, respectively. Therefore, this model was useful to predict the progress of systemic infections by PVY in potato plants, and to construct the epidemic models.

• The Journal of Korean Society for School & Community Health Education
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• v.20 no.3
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• pp.53-65
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• 2019

Objectives: The purpose of this study is to examine the current status of cancer screening among subjects in the lung cancer screening cycle and to analyze the factors affecting the cancer screening of subjects in the lung cancer screening cycle. Methods: This study used the 'National Health and Nutrition Survey 7th Year (2017)' surveyed nationwide as the main data. The subjects are lung cancer screening projects, the dependent variable is early cancer screening, the independent variables are gender, age, marital status, household income level, education level, national health insurance type, private health insurance, The number of chronic diseases, general health examination, smoking status, drinking status, moderate intensity physical activity, stress perception rate, and weight control efforts were determined. Results: The results of this study showed that factors affecting early cancer screening of lung cancer screening subjects were gender, age, marital status, education level, national health insurance, smoking status, drinking status, moderate physical activity, and weight. Irrespective of the control effort, it was found that the private medical insurance, the number of chronic diseases, the medical examination, and the stress perception rate were affected. Conclusion: If the lung cancer screening subjects recognize the importance of early cancer screening themselves and create a social environment to increase their participation rate, lung cancer screening patients and their families will help them to live a healthy life.

• Journal of Chest Surgery
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• v.19 no.2
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• pp.197-208
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• 1986

Propranolol is one of clinically useful antiarrhythmic agents and electrophysiologically classified as group II. And the negative inotropic effect which is not related to adrenolytic effect has been demonstrated with high concentration of propranolol. On the other hand, it has been well known that the calcium plays a central role in excitation-contraction coupling process of myocardium and also in electrophysiological changes of cell membrane. Author studies the effect of propranolol on calcium uptake and release in sarcoplasmic reticulum and mitochondria prepared from porcine myocardium to investigate the mechanism of action of propranolol on myocardium. The results are summarized as follow: 1] The maximum Ca++-uptake of sarcoplasmic reticulum is inhibited by propranolol in a dose dependent manner. 2] The release of calcium from sarcoplasmic reticulum is not affected by propranolol but with higher than 1x10-3 M of propranolol, rate of calcium release from sarcoplasmic reticulum is decreased. 3] Propranolol inhibits the maximum uptake and uptake rate of calcium in mitochondria non-competitively. [Ki = 6.21 x 10-4 M] 4] The rate of Na+ induced calcium release from mitochondrion shows a function of [Na+]2 and is inhibited by propranolol with the concentration significantly lower than that affect the calcium uptake in sarcoplasmic reticulum and in mitochondria [Ki = 2.91 x 10-5 M]. These results suggest that propranolol affects the intracellular calcium homeostasis which may considered to be one of the mechanism of action of propranolol on myocardium.