• Sleep Medicine and Psychophysiology
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• v.9 no.1
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• pp.24-33
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• 2002

Objectives: Nasal continuous positive airway pressure (CPAP) corrected elevated blood pressure (BP) in some studies of obstructive sleep apnea syndrome (OSAS) but not in others. Such inconsistent results in previous studies might be due to differences in factors influencing the effects of CPAP on BP. The factors referred to include BP monitoring techniques, the characteristics of subjects, and method of CPAP application. Therefore, we evaluated the effects of one night CPAP application on BP and heart rate (HR) reactivity using non-invasive beat-to-beat BP measurement in normotensive and hypertensive subjects with OSAS. Methods: Finger arterial BP and oxygen saturation monitoring with nocturnal polysomnography were performed on 10 OSAS patients (mean age $52.2{\pm}12.4\;years$; 9 males, 1 female; respiratory disturbance index (RDI)>5) for one baseline night and another CPAP night. Beat-to-beat measurement of BP and HR was done with finger arterial BP monitor ($Finapres^{(R)}$) and mean arterial oxygen saturation ($SaO_2$) was also measured at 2-second intervals for both nights. We compared the mean values of cardiovascular and respiratory variables between baseline and CPAP nights using Wilcoxon signed ranks test. Delta ($\Delta$) BP, defined as the subtracted value of CPAP night BP from baseline night BP, was correlated with age, body mass index (BMI), baseline night values of BP, BP variability, HR, HR variability, mean $SaO_2$ and respiratory disturbance index (RDI), and CPAP night values of TWT% (total wake time%) and CPAP pressure, using Spearman's correlation. Results: 1) Although increase of mean $SaO_2$ (p<.01) and decrease of RDI (p<.01) were observed on the CPAP night, there were no significant differences in other variables between two nights. 2) However, delta BP tended to increase or decease depending on BP values of the baseline night and age. Delta systolic BP and baseline systolic BP showed a significant positive correlation (p<.01), but delta diastolic BP and baseline diastolic BP did not show a significant correlation except for a positive correlation in wake stage (p<.01). Delta diastolic BP and age showed a significant negative correlation (p<.05) during all stages except for REM stage, but delta systolic BP and age did not. 3) Delta systolic and diastolic BPs did not significantly correlate with other factors, such as BMI, baseline night values of BP variability, HR, HR variability, mean SaO2 and RDI, and CPAP night values of TWT% and CPAP pressure, except for a positive correlation of delta diastolic pressure and TWT% of CPAP night (p<.01). Conclusions: We observed that systolic BP and diastolic BP tended to decrease, increase or remain still in accordance with the systolic BP level of baseline night and aging. We suggest that BP reactivity by CPAP be dealt with as a complex phenomenon rather than a simple undifferentiated BP decrease.

• Journal of Dairy Science and Biotechnology
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• v.34 no.2
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• pp.99-116
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• 2016

We herein performed animal safety assessment in accordance with Good Laboratory Practice (GLP) regulations with the aim of developing sialic acid from glycomacropeptide (hereafter referred to as "GMP") as an index ingredient and functional component in functional foods. GMP is a type of whey protein derived from milk and a safe food, with multiple functions, such as antiviral activity. A test substance was produced containing 7% (w/w) sialic acid and mostly-hydrolyzed whey protein (hereafter referred to as "7%-GNANA") by enzymatic treatment of substrate GMP. The maximum intake test dose level was selected based on 5,000 mg/kg/day dose set for male NOEL (no-observed-effect-level) and female NOAEL (no-observed-adverse-effect-level) determined by a dose-range finding (DRF) test (GLP Center of Catholic University of Daegu, Report No. 15-NREO-001) that was previously conducted with the same test substance. To evaluate the toxicity of a repeated oral dose of the test substance in connection with the previous DRF study, 1,250, 2,500, and 5,000 mg/kg of the substance were administered by a probe into the stomachs of 6-week-old SPF Sprague-Dawley male and female rats for 90 d. Each test group consisted of 10 male and 10 female rats. To determine the toxicity index, all parameters, such as observation of common signs; measurements of body weight and food consumption; ophthalmic examination; urinalysis, electrolyte, hematological, and serum biochemical examination; measurement of organ weights during autopsy; and visual and histopathological examinations were conducted according to GLP standards. After evaluating the results based on the test toxicity assessment criteria, it was determined that NOAEL of the test substance, 7%-GNANA, was 5,000 mg/kg/day, for both male and female rats. No animal death was noted in any of the test groups, including the control group, during the study period, and there was no significant difference associated with test substance, as compared with the control group, with respect to general symptoms, body weight changes, food consumption, ophthalmic examination, urinalysis, hematological and serum biochemical examination, and electrolyte and blood coagulation tests during the administration period (P<0.05). As assessed by the effects of the test substance on organ weights, food consumption, autopsy, and histopathological safety, change in kidney weight as an indicator of male NOAEL revealed up to 20% kidney weight increase in the high-dose group (5,000 mg/kg/day) compared with the change in the control group. However, it was concluded that this effect of the test substance was minor. In the case of female rats, reduction of food consumption, increase of kidney weight, and decrease of thymus weight were observed in the high-dose group. The kidney weight increased by 10.2% (left) and 8.9% (right) in the high-dose group, with a slight dose-dependency compared with that of the control group. It was observed that the thymus weight decreased by 25.3% in the high-dose group, but it was a minor test substance-associated effect. During the autopsy, botryoid tumor was detected on the ribs of one subject in the high-dose group, but we concluded that the tumor has been caused by a naturally occurring (non-test) substance. Histopathological examination revealed lesions on the kidney, liver, spleen, and other organs in the low-dose test group. Since these lesions were considered a separate phenomenon, or naturally occurring and associated with aging, it was checked whether any target organ showed clear symptoms caused by the test substance. In conclusion, different concentrations of the test substance were fed to rats and, consequently, it was verified that only a minor effect was associated with the test substance in the high-dose (5,000 mg/kg/day) group of both male and female rats, without any other significant effects associated with the test substance. Therefore, it was concluded that NOAEL of 7%-GNANA (product name: Helicobactrol) with male and female rats as test animals was 5,000 mg/kg/day, and it thus was determined that the substance is safe for the ultimate use as an ingredient of health functional foods.

• Journal of Global Scholars of Marketing Science
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• v.18 no.2
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• pp.223-252
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• 2008

In this study, we attempt to propose a choice-based diffusion model with switching cost, which can be used to forecast the dynamic substitution and competition among previous and new products at both individual-level and aggregate level, especially when market data for new products is insufficient. Additionally, we apply the proposed model to the empirical case of substitution and competition among Analog Cable TV that represents previous fixed charged broadcasting service and Digital Cable TV and Internet Protocol TV (IPTV) that are new ones, verify the validities of our proposed model, and finally derive related empirical implications. For empirical application, we obtained data from survey conducted as follows. Survey was administered by Dongseo Research to 1,000 adults aging from 20 to 60 living in Seoul, Korea, in May of 2007, under the title of 'Demand analysis of next generation fixed interactive broadcasting services'. Conjoint survey modified as follows, was used. First, as the traditional approach in conjoint analysis, we extracted 16 hypothetical alternative cards from the orthogonal design using important attributes and levels of next generation interactive broadcasting services which were determined by previous literature review and experts' comments. Again, we divided 16 conjoint cards into 4 groups, and thus composed 4 choice sets with 4 alternatives each. Therefore, each respondent faces 4 different hypothetical choice situations. In addition to this, we added two ways of modification. First, we asked the respondents to include the status-quo broadcasting services they subscribe to, as another alternative in each choice set. As a result, respondents choose the most preferred alternative among 5 alternatives consisting of 1 alternative with current subscription and 4 hypothetical alternatives in 4 choice sets. Modification of traditional conjoint survey in this way enabled us to estimate the factors related to switching cost or switching threshold in addition to the effects of attributes. Also, by using both revealed preference data(1 alternative with current subscription) and stated preference data (4 hypothetical alternatives), additional advantages in terms of the estimation properties and more conservative and realistic forecast, can be achieved. Second, we asked the respondents to choose the most preferred alternative while considering their expected adoption timing or switching timing. Respondents are asked to report their expected adoption or switching timing among 14 half-year points after the introduction of next generation broadcasting services. As a result, for each respondent, 14 observations with 5 alternatives for each period, are obtained, which results in panel-type data. Finally, this panel-type data consisting of $4{\ast}14{\ast}1000=56000$observations is used for estimation of the individual-level consumer adoption model. From the results obtained by empirical application, in case of forecasting the demand of new products without considering existence of previous product(s) and(or) switching cost factors, it is found that overestimated speed of diffusion at introductory stage or distorted predictions can be obtained, and as such, validities of our proposed model in which both existence of previous products and switching cost factors are properly considered, are verified. Also, it is found that proposed model can produce flexible patterns of market evolution depending on the degree of the effects of consumer preferences for the attributes of the alternatives on individual-level state transition, rather than following S-shaped curve assumed a priori. Empirically, it is found that in various scenarios with diverse combinations of prices, IPTV is more likely to take advantageous positions over Digital Cable TV in obtaining subscribers. Meanwhile, despite inferiorities in many technological attributes, Analog Cable TV, which is regarded as previous product in our analysis, is likely to be substituted by new services gradually rather than abruptly thanks to the advantage in low service charge and existence of high switching cost in fixed charged broadcasting service market.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.4
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• pp.166-175
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• 2015

Nowadays, in the European countries, landscape is spoken of its importance as often as environment, by those who are engaged in such fields as politics, administration, research and civil society. In Korea, while recognizing such an international trend, academics and administrators have made a series of efforts to reflect landscape concept on a variety of policies. However, it is recognized that the effects of these policies have not been satisfactory. Under these circumstances, this paper aims to examine the complex values and multiple meanings in the landscape, which have been discussed by landscape experts in the European countries. Then, it aims to the explore the future direction of policy and research on the landscape to be pursued in Korea, where there is relatively less interest in the issues of landscape. It is argued that landscape should be approached and understood from a holistic perspective, because it is a very complex concept with multiple meanings that have been coined differently depending on the situation. All the academic fields, involved in the landscape research, should try in co-operation to develop the comprehensive approach rather than the inter- and multi-disciplinary approach to the landscape study. In Korea, moreover, it is also necessary in the legislation to recognize the fact that degradation and retreat in the quality of landscape would make a negative effect on the quality of human daily life. Natural and cultural heritages contained in the rural landscape are also now in danger of disappearing. These heritages, therefore, should become an important subject for research and policy on landscape before the countryside is completely evacuated after the aging population die out. To make this happen, it is very urgent that evaluation and classification of landscape character should be undertaken from the holistic perspective, which is equipped with a methodology overcoming as well as encompassing the boundaries of academic fields. It is also equally very urgent that education on landscape should be provided to the politicians, citizens and students as well as the officials dealing with landscape matters. Finally, government should strive to make the landscape concept penetrate deeply as well as widely into the spatial planning and legislation process while designing and implementing a comprehensive landscape policy at the national level.

• Journal of Nutrition and Health
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• v.35 no.3
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• pp.291-295
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• 2002

This study was designed to investigate the effects of a butanol (BuOH) fraction from an extract of pine (Pinus densiflora Sieb et Zucc.) needles, on oxygen radicals and their scavenger enzymes in the liver membranes of rats. Twenty-eight male Sprague-Dawley (SD) rats were divided into four groups over a 45 days study period: the control group on a basic diet, and three experimental groups on three different dietary levels of the butanol fraction, specifically 25 mg (BuOH-25), 50 mg (BuOH-50), and 100 mg (BuOH-100) butanol fraction/kg body weight/day, thereby 0.025%, 0.05%, 0.1% of butanol extract of pine needles was added to basil diet respectively. At the end of the experimental period, body weights and food intakes were not different among the four groups. The results showed that cholesterol accumulation in the mitochondria and microsomes of liver cells was significantly inhibited in the BuOH-50 and BuOH-100 groups: by 11.6% and 20.1% in the mitochondria of the BuOH-50 and BuOH-100 groups, respectively; and by 10.5%, and 13.5% in the microsomes of the BuOH-50 and BuOH-100 groups, respectively, compared with the control group. The levels of hydroxyl radicals (.OH) were significantly) lower in the liver mitochondria of the BuOH-50 and BuOH-100 groups (by 13.3% and 18.5%, respectively), while OH radicals were significantly lower in the microsomes or all three experimental groups (by 15.7% in the BuOH-25 group, 20.0% in the BuOH-50 group, and 20.6% in the BuOH-100group), compared with the control group. Superoxide radical (O$_2$) formation was also significantly inhibited in the liver cytosol of both BuOH-50 and BuOH-100 groups; the levels of these radicals were 8.0% lower for the BuOH-50 group and 11.1% lower for the BuOH-100 group, compared to the control group. Copper/Zinc - superoxide dismutase (Cu/Zn-SOD) activities were significantly increased (by 10.3% and 15.9%, respectively) in the liver cytosols of the BuOH-50 and BuOH-100 groups, but Mn-SOD activities were almost identical in the three RuOH groups, compared with the control group. Glutathione peroxidase (GPx) activities were significantly increased in the three experimental groups (by 9.0% in the BuOH-25 group, 19.4% in the BuOH-50 group, and by 25.6% in the BuOH-100 group), compared with the control group. These results suggest that the butanol extract of pine needles may play an effective role in attenuating oxygen radicals and activating scavenger enzymes; consequently, aging may be very effectively modulated and/or inhibited.

• Korean Journal of Clinical Pharmacy
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• v.16 no.2
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• pp.86-91
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• 2006

There are 3 different hypotheses on how statins may affect bones, through promoting bone formation, inhibiting bone resorption or through anti-inflammatory effect. In the 3 cross-sectional studies above, one showed increase BMD at hip and spine, one showed increase BMD only at mid-forearm and one showed that the risk reduction in fractures is not explained by the changes in BMD however, all 3 studies showed a decrease in risk of fracture associated with statins. In the 2 prospective cohort studies, one showed the use of statins was not associated with BMD at any skeletal site or decreasing the risk of fracture, and the other showed statins except pravastatin decreased in risk of vertebrate fracture but not affecting lumbar spine BMD. All of case-control studies indicated reduction in fracture risk but did not provide any data regarding BMD. 2 of the randomized, controlled studies showed no significant reduction in fracture risk as well as statins' effects on BMD. Finally, one longitudinal study showed statin use reduced fracture risk and increased BMD. Among the conflicting results shown above, even when statin use was shown to increase BMD, it does not seem to account for the reduction in fracture risk. There may be different ways that statins affect bone other than those hypotheses proposed above. Many studies seem to agree that pravastatin does not have any effect on bone. Some studies suggested that the reason statins did not achieve clinically significant increases in BMD in some studies, is due to the low affinity of statins on bone; statins are designed to act in the liver therefore their effective concentration in extrahepatic tissue is low. The limitations to those studies discussed above. Many studies did not account for the change of lifestyle while subjects' were on statins. Increases in weight bearing exercise and changes in diet might affect BMD and thus reduce risk of fractures. Mental alertness and vision acuity might prevent falls from occurring; many statin-users in the studies were young so the risk of fractures from falls would be decreased. Almost all of the studies failed exclude patients with neurological problems. During study periods, many subjects may have been started on drugs for diseases that usually occur with aging which could cause drowsiness and lead to falls. The sample sizes used in some of the trials were small and the duration of treatment and follow up might not have been long enough to see clinically relevant results.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.29-34
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• 2015

N,N'-Diferuloyl-putrescine (DFP) present in plants such as Sophora japonica has been reported to have skin depigmentative and antioxidative activities. In this study, DFP, usually presents in nature a very little amount and its derivative (DFP-D) were synthesized in a large quantity for the use as functional cosmetical materials. The antioxidative activities of synthesized DFP and DFP-D were evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, chemiluminescence assay, and cell protective effect induced by $^1O_2$, stress. DFP and DFP-D showed DPPH radical scavenging activities ($FSC_{50}$) at $61.25{\pm}2.25{\mu}M$ and $12.92{\pm}0.72{\mu}M$, respectively. ROS (reactive oxygen species) scavenging activities ($OSC_{50}$) in the $Fe^{3+}-EDTA/H_2O_2$ system of DFP and DFP-D were 2 times ($1.84{\pm}0.12{\mu}M$) and 13 times ($0.174{\pm}0.01{\mu}M$), respectively higher than that of L-ascorbic acid. $^1O_2$, one of ROS playing a key role in the skin photo-aging, induces cellular membrane damages. DFP-D ($50{\mu}M$) showed good cell protective effects (${\tau}_{50}=80.2min$) about 2 times more than that of (+)-${\alpha}$-tocopherol (${\tau}_{50}=43.6min$). These results suggest that the great antioxidative activities of DFP and DFP-D could be applied to cosmetic industries as functional cosmetic materials.

• The Korean Journal of Mycology
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• v.29 no.1
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• pp.41-46
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• 2001

Oxidative stress and defense system of SD-rats were studied with an edible Nigerian mushroom, namely, Lentinus tuber-regium (Fries) Singer. Experimental diets prepared with Lentinus tuber-regium (LTR) instead of carbohydrates were fed to SD rats for 6 weeks. Hydrolxyl radical $({\cdot}OH)$ formations were significantly inhibited (21.7% and 16.4%, respectively). In LTR-50 and LTR-100 groups used instead of carbohydrates, and hydrogen peroxide and nitric oxide (NO) were also significantly inhibited by 10%, and $6{\sim}10%$, respectively compared with control group, but there was no significant changes in superoxide radical $({O_2}^-)$ formations in these groups. Lipid peroxide (LPO) and oxidized protein (OP) levels as an oxidative stress were desirably inhibited ($6{\sim}12%\;and\;5{\sim}13%$, respectively) in these LTR groups compared with control group. Superoxide dismutase (SOD), glutathione peroxidase (GSHPx) and catalase (CAT) activities were significantly increased ($15{\sim}50%,\;10{\sim}25%\;and\;60{\sim}90%$, respectively) in these LTR groups. These results suggest that an edible mushroom, Lentinus tuber-regium may inhibit an oxygen radicals and oxidative stresses, but may also effectively modulate an aging processes.

• Journal of Preventive Medicine and Public Health
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• v.31 no.1 s.60
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• pp.91-103
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• 1998

Under experimental conditions, UVB radiation, a type of ultra violet radiation, has shown to .elate with the occurrence of skin erythema (sun-burn) in human and skin cancer in experimental animal. Cumulative exposure to UVB is also believed to be at least partly responsible for the 'aging' process of the skin in human. It has also been observed to have an effect of altering DNA (deoxyribonucleic acid). UVB radiation is both an initiator and a promoter of non-melanoma skin cancer. Meta-analysis is a new discipline that critically reviews and statistically combines the results of previous researches. A recent review of meta-analysis in the field of public health emphasized its growing importance. Using a meta-analysis in this study, we explored more reliable dose-response relationships between UVB radiation and skin cancer incidence. We estimated skin cancer incidence using measured UVB radiation dose at a local area of Seoul (Shin chou-dong). The studies showing the dose-response relationships between UVB radiation and non-melanoma skin cancer incidence were searched and selected for a meta-analysis. The data for 7 reported epidemiological studies of three counties (USA, England, Australia) were pooled to estimated the risk. We estimated rate of incidence change of skin cancer using pooled data by meta-analysis method, and exponential and power models. Using either model, the regression coefficients for UVB did not differ significantly by gender and age. In each analysis of variance, non-melanoma skin cancer incidence after removing the gender and age and UVB effects was significant (p>0.01). The coefficients for UVB dose were estimated $2.07\times10^{-6}$ by the exponential model and 2.49 by the power model. At a local area of Seoul (Shinchon-Dong), BAF value were estimated 1.90 and 2.51 by the exponential and power model, respectively. The estimated BAP value were increased statistical power than that of primary studies that using a meta-analysis method.

• Journal of the Korean Applied Science and Technology
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• v.37 no.2
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• pp.153-161
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• 2020

Arthrospira platensis is the oldest marine microalgae on the planet, is said to contain most of the nutrients needed by the human body. It's components are reported to contain a large amount of various substances such as phycocyanin, chlorophyll and β-carotene, and are known to have an aging and whitening effect. In this study, UVB-induced reactive oxygen species reduction efficacy and antioxidant activity of spirulina purified water extract were investigated. effect was confirmed by measuring DPPH radical scavenging activity, FRAP reducing power and ABTS⁺ radical scavenging activity of 0.05, 0.10, 0.50 1.0 mg/mL of spirulina purified water extract. The coagulation rate, hatching rate and heart rate toxicity were measured by treating spirulina purified water extract with 0.05, 0.10, 0.50 mg/mL concentration using Zebrafish, an alternative experimental animal model. UVB-induced ROS measurement was treated with spirulina extract at 0.05, 0.10, 0.50 mg/mL concentration, and then stained with DCFH-DA to confirm the inhibitory effect of ROS. As a result of measuring antioxidant effect, DPPH, FRAP and ABTS⁺ showed concentration-dependent antioxidant effects in comparison with ascorbic acid. and measuring the coagulation rate, hatching rate, and heart rate using Zebrafish, an alternative experimental animal, it was confirmed that there was no toxicity in 0.05 and 0.10 mg/mL except 0.5 mg/mL compared to the control group. The ROS scavenging activity of UVB-induced zebrafish showed higher ROS reduction than the positive control. The results of this study suggest that spirulina and purified water extracts are valuable for UV and skin protection cosmetics.