• 한국노년학
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• v.40 no.4
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• pp.781-800
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• 2020

This study aims to categorize the daily time use of older adults into different types, examine the factors influencing them and the differences between them by type, and verify the effect of each type on life satisfaction. From the 6th wave of the Korea Retirement and Income Study (KeRIS), analysis was conducted on 3,963 older adults aged 65 (n=3,963). Using Latent Profile Analysis (LPA), three types of daily time use for older adults were identified: basic life maintenance type (16%), free-leisure oriented type (26%), and social activity type (58%). From the results of multinomial logistic regression analysis to identify the factors influencing each type of daily time use, it was found that the main factors influencing free-leisure oriented type, when compared with basic life maintenance type, were the presence of spouse (p<.01) and psychological health status (p<.001). The main factors influencing social activity type, when compared with basic life maintenance type, were age (p<.05), economic activity (p<.001), and chronic disease (p<.001). The life satisfaction seen during free-leisure oriented time and social activity time was higher than that during basic life maintenance time. From these findings, practical and policy proposals were suggested to improve life satisfaction of older adults during basic life maintenance time by pursuing changes in the use of that time.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.337-340
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• 2000

In this paper, I compared some characteristics between HPA and LPA using Feedforward method. Feedforward method is known for best IMD correction. HPA generated 46.5㏈c at 45.5㏈m output power. But, using feedforward linearing method, I could improve IMD to 67.17㏈c at the same output power. IMD could be improved 20.67㏈ at 45.5㏈m output power. I measured average power, IMD, total current, and efficiency of two amplifier at many different power levels. I could get about 70d3c IMD using feedforward method.

• Molecules and Cells
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• v.37 no.9
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• pp.656-663
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• 2014

Gintonin, a novel, ginseng-derived G protein-coupled lysophosphatidic acid (LPA) receptor ligand, elicits $[Ca^{2+}]_i$ transients in neuronal and non-neuronal cells via pertussis toxin-sensitive and pertussis toxin-insensitive G proteins. The slowly activating delayed rectifier $K^+$ ($I_{Ks}$) channel is a cardiac $K^+$ channel composed of KCNQ1 and KCNE1 subunits. The C terminus of the KCNQ1 channel protein has two calmodulin-binding sites that are involved in regulating $I_{Ks}$ channels. In this study, we investigated the molecular mechanisms of gintonin-mediated activation of human $I_{Ks}$ channel activity by expressing human $I_{Ks}$ channels in Xenopus oocytes. We found that gintonin enhances $I_{Ks}$ channel currents in concentration- and voltage-dependent manners. The $EC_{50}$ for the $I_{Ks}$ channel was $0.05{\pm}0.01{\mu}g/ml$. Gintonin-mediated activation 1 of the $I_{Ks}$ channels was blocked by an LPA1/3 receptor antagonist, an active phospholipase C inhibitor, an $IP_3$ receptor antagonist, and the calcium chelator BAPTA. Gintonin-mediated activation of both the $I_{Ks}$ channel was also blocked by the calmodulin (CaM) blocker calmidazolium. Mutations in the KCNQ1 $[Ca^{2+}]_i$/CaM-binding IQ motif sites (S373P, W392R, or R539W)blocked the action of gintonin on $I_{Ks}$ channel. However, gintonin had no effect on hERG $K^+$ channel activity. These results show that gintonin-mediated enhancement of $I_{Ks}$ channel currents is achieved through binding of the $[Ca^{2+}]_i$/CaM complex to the C terminus of KCNQ1 subunit.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.9
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• pp.6-12
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• 1999

It is difficult to realize adaptive main carrier rejection circuit in feedforward-type LPA(Linear Power Amplifier) because the gain and nonlinear characteristics of power amplifier are changed according to operating frequency, voltage, temperature. Usually, pilot tones are used for adaptive LPA operation. but in this paper, the relative phase, which in obtained through I&Q demodulator using input signals as LO signals and main-path & sub-path signals as RF signals, and the magnitude of main-path & sub-path signals are compared, so main carrier rejection is obtained. The proposed method rejects main carriers by 28.34 ~ 34.66dB (@Po=36.2 ~ 28.2 dBm/tone) with two tones at 877MHz, 882MHz and also rejects main carriers by 31.3dB despite changing condition of operating voltage.

• The Journal of the Korea Contents Association
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• v.20 no.9
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• pp.365-379
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• 2020

The purpose of this study identifies the patterns of students' learning motivation profiles on entrepreneurial educational motivation among a sample of university students from one of the Korean national university(n=614). This study also examines the relationship between students' learning motivation profiles and entrepreneurial intention and types of entrepreneurship. In order to explore the types of leaning motivation profiles, a latent profile analysis was employed. Result from LPA revealed five distinct types of learning motivation profiles fit the data best, and these five profiles are compared with students' entrepreneurial intentions and types of entrepreneurship. Results showed that Profiles (profile 5 and 4-high goal orientation) are associated with the higher level of entrepreneurial intention. Regarding the type of entrepreneurship, the majority of all students are interested in individual and co-entrepreneurship with friend regardless of the patterns of profiles.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3219-3226
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• 2014

Chemotherapy continues to be a mainstay of cancer treatment, although drug resistance is a major obstacle. Lipid metabolism plays a critical role in cancer pathology, with elevated ether lipid levels. Recently, alkylglyceronephosphate synthase (AGPS), an enzyme that catalyzes the critical step in ether lipid synthesis, was shown to be up-regulated in multiple types of cancer cells and primary tumors. Here, we demonstrated that silencing of AGPS in chemotherapy resistance glioma U87MG/DDP and hepatic carcinoma HepG2/ADM cell lines resulted in reduced cell proliferation, increased drug sensitivity, cell cycle arrest and cell apoptosis through reducing the intracellular concentration of lysophosphatidic acid (LPA), lysophosphatidic acid-ether (LPAe) and prostaglandin E2 (PGE2), resulting in reduction of LPA receptor and EP receptors mediated PI3K/AKT signaling pathways and the expression of several multi-drug resistance genes, like MDR1, MRP1 and ABCG2. ${\beta}$-catenin, caspase-3/8, Bcl-2 and survivin were also found to be involved. In summary, our studies indicate that AGPS plays a role in cancer chemotherapy resistance by mediating signaling lipid metabolism in cancer cells.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.233-241
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• 2001

Dirofilaria immitis, the causative agent of canine heartworm disease, inhabits mainly in the pulmonary arteries and the heart of dogs and cats, causing circulatory and respiratory disorders. Although diagnosis of the disease is based on the presence of microfilaria in the peripheral blood or of specific antigens released from the adult worms into the peripheral blood, the severity of the infection and the assessment of disease progression are based on the clinical signs and radiographic image analysis. We analysed 12 mixed-bred Jindo dogs naturally infected with Dirofilaria immitis without any clinical signs and compared the radiographic images of the heart and the lung with the number of adult worms at necropsy. The dorsoventral radiographs of 12 infected dogs revealed that the right caudal lobar pulmonary arteries (RCaLPA) were dialated in 66.7% of dogs, whereas the main pulmonary artery segment was enlarged in 50.3% of dogs. The cranial lobar pulmonary arteries (RCrLPA) were dilated or pruned in 33.3% of dogs. All dogs displayed the interstitial lung pattern, while the vertebral heart size (VHS) was of normal range. Although a range of 9 to 166 adult worms (av. 45.6) was found in the pulmonary arteries, in the heart or in the vena cava, no correlation with the radiographic findings and/or with the clinical signs was observed.

• Journal of Chest Surgery
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• v.21 no.6
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• pp.957-969
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• 1988

There is tendency of increasing number and decreasing age of patients who are indicated for Rastelli operation for their cyanotic congenita heart disease. So there is the need to find the creiterion which saves the patients from early postoperative hemodynamic disturbances. We reviewed the 26 patients who had been performed Rastelli operation at Seoul national University hOipital from January 1981 to June 1988. mean age of the patients was 7.8 $\pm$ 3.4 years (range 2.5-1.5 years), mean body surface area(BSA) 0.79 $\pm$ 0.25 $m^{2}$(range 0.49-1.51 $m^{2}$) and mean hematocrit 57.95 $\pm$ 12%(range 48-80%). We diveded these patients into survived group and died group before postoperative 72 hours, and analysed preoperative arterial oxygen saturation($SaO_{2}$), the ratio of diameter of fight pulmonary artery to ascending aorta(RA:/AA), the ratio of both right and left pulmonary artery diameter to descending thoracic aorta(RPA+LPA/DTA), pulmonary artery index(PA index), cardiopulmonary bypass time, aorta cross-clamping time, postoperative perfusion state and total amount of dopamine infused postoperatively. The results showed that RPA+LPA/DTA and PA index were statistically significatn factors to influence early postoperative cardiac death rate (P<0.05). Especially there were good linear correlations between PA index(X) and perpheral perfusion index(Y)(Y = -1.15 + 0.02 X, r = 0.86, P<0.01) and between PA index(X) and total amount of dopamine infused before postoperative 72 hours(mg/kg, Y)(Y = 61.94 - 0.15 X, r = - 0.80, P<0.01). Also there were tendencies that the higher RPA + LPA/DTA(Y), the betterperipheral perfusion (X) and the lower need of dopamine(X), but no statistical significance. (Y = 0.78 + 1.60 X, r = 0.49, P>0.05) And the discrimant analysis showed that patients with PA index over 221 $mm^{2}$/BSA could undergo correction with 25 per cent of error rate. In conclusion, early postoperative hemodynamic states could be predicted by preoperatively measured PA index, and which can be used as a criterion for Rastelli operation performed on cyanotic congenital heart disease.

• Korean Journal of Social Welfare
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• v.68 no.2
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• pp.213-232
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• 2016

The purpose of this study is to explore the stress profile that adolescent perceives by using Latent Profile Analysis (LPA), and to examine the effect of characteristics variable per groups that appeared in profile. By using the cross-section data of 'A survey on the human right of Korean children and adolescent in 2013' issued by National Youth Policy Institute, the LPA concerning the stress type was conducted and surveyed 9,521 adolescents from fourth grade in elementary school to seniors in high school nationwide. The result of this study shows that two class types were selected according to the goodness-of-fit index and latent class classification rate. Type 1 is named low-risk group as they show low level, whereas type 2 is named relative risk group as they show high level. In order to predict the characteristics of adolescent stress, the study conducted Binary Logistic Regression analysis on the basis of low-risk group. There is higher probability to belong to relative risk group, the more they are female students than male students, the less their subjective health condition and happiness, the more runaway experience, the less school grades and the less economic affluence in their household. The implication of this research, its limitation and direction of follow-up research were suggested.

• Journal of Ginseng Research
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• v.43 no.2
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• pp.305-311
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• 2019

Background: Gintonin is a ginseng-derived exogenous ligand of the G protein-coupled lysophosphatidic acid (LPA) receptor. We previously reported that gintonin stimulates gliotransmitter release in primary cortical astrocytes. Astrocytes play key roles in the functions of neurovascular systems. Although vascular endothelial growth factor (VEGF) is known to influence the normal growth and maintenance of cranial blood vessels and the nervous system, there is little information about the effect of gintonin on VEGF regulation in primary astrocytes, under normal and hypoxic conditions. Methods: Using primary cortical astrocytes of mice, the effects of gintonin on the release, expression, and distribution of VEGF were examined. We further investigated whether the gintonin-mediated VEGF release protects astrocytes from hypoxia. Results: Gintonin administration stimulated the release and expression of VEGF from astrocytes in a concentration- and time-dependent manner. The gintonin-mediated increase in the release of VEGF was inhibited by the LPA1/3 receptor antagonist, Ki16425; phospholipase C inhibitor, U73122; inositol 1,4,5- triphosphate receptor antagonist, 2-APB; and intracellular $Ca^{2+}$ chelator, BAPTA. Hypoxia further stimulated astrocytic VEGF release. Gintonin treatment stimulated additional VEGF release and restored cell viability that had decreased due to hypoxia, via the VEGF receptor pathway. Altogether, the regulation of VEGF release and expression and astrocytic protection mediated by gintonin under hypoxia are achieved via the LPA receptor-VEGF signaling pathways. Conclusion: The present study shows that the gintonin-mediated regulation of VEGF in cortical astrocytes might be neuroprotective against hypoxic insults and could explain the molecular basis of the beneficial effects of ginseng on the central nervous system.