• Journal of Chest Surgery
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• v.37 no.6
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• pp.482-491
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• 2004

Background: The xenogenic or allogenic valves after in Vitro repopulation with autologous cells or in vivo repo-pulation after acellularization treatment to remove the antigenicity could used as an alternative to synthetic polymer scaffold. In the present study, we evaluated the process of repopulation by recipient cell to the acellu-larized xenograft treated with NaCl-SDS solution and grafted in the right ventricular outflow tract. Material and Method: Porcine pulmonary valved conduit were treated with. NaCl-SDS solution to make the grafts acellularized and implanted in the right ventricular outflow tract of the goats under cardiopulmonary bypass. After evaluating the functions of pulmonary valves by echocardiography, goats were sacrificed at 1 week, 1 month, 3 months, 6 months, and 12 months after implantation, respectively. After retrieving the implanted valved conduits, histopathologic examination with Hematoxylin-Eosin, Masson' trichrome staining and immunohistochemical staining was performed. Result: Among the six goats, which had been implanted with acellularized pulmonary valved conduits, five survived the expected time period. Echocardiographic examinations for pulmonary valves revealed good function except mild regurgitation and stenosis. Microscopic analysis of the leaflets showed progressive cellular in-growth, composed of fibroblasts, myofibroblasts, and endothelial cells, into the acellularized leaflets over time. Severe inflammatory respon-se was detected in early phase, though it gradually decreased afterwards. The extracellular matrices were regenerated by repopulated cells on the recellularized portion of the acellularized leaflet. Conclusion: The acellularized xenogenic pulmonary valved conuits were repopulated with fibroblasts, myofibroblasts, and endothelial cells of the recipient and extracellullar matrices were regenerated by repopulted cells 12 months after the implantation. The functional integrity of pulmonary valves was well preserved. This study showed that the acellularized porcine xenogenic valved conduits could be used as an ideal valve prosthesis with long term durability.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.433-445
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• 2019

This study was designed to develop simple tools to easily and efficiently predict the occurrence of algal bloom in agricultural lakes. Physicochemical water quality parameters were examined to reflect the phytoplankton productivity in 182 samples collected from 15 agricultural lakes from April to October 2018. Total phytoplankton abundance was significantly correlated with chlorophyll-a (Chl-a) (r=0.666) and Secchi depth (SD) (r= -0.351). The abundances of cyanobacteria and harmful cyanobacteria were also correlated with Chl-a (r=0.664, r=0.353) and SD (r= -0.340, r= -0.338), respectively, but not with total nitrogen (TN) and total phosphorus (TP). The Chl-a concentration was correlated with SD (r= -0.434), showing a higher similarity than phytoplankton abundance. Therefore, Chl-a and SD were selected as diagnostic factors for algal bloom prediction, instead of analyzing the standing crop of harmful cyanobacteria used in algae alarm systems. Specifically, accurate diagnoses were made using realtime SD measurements. The algal bloom diagnostic tool is an inverse cone-shaped container with an algal bloom diagnosis chart that modified SD and turbidity measurement methods. Lake water was collected to observe the number of rings visible in the container or the number indicated in each ring, depending on the degree of algal bloom,and to determine the final stage of algal blooming by comparison to the colorimetric level on the diagnosis chart. For an accurate diagnosis, we presented 4-step diagnostic criteria based on the concentration of Chl-a and the number of rings and a fan-shaped algal bloom diagnosis chart with Hexa code names. This tool eliminated the variables and errors of previous methods and the results were easily interpreted. This study is expected to facilitate the diagnosis of algal bloom in agricultural lakes and the establishment of an efficient algal bloom management plan.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.65-74
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• 2011

Purpose: In this study we investigated improvement degree of reading ability of the student who was in a condition of dyslexia symptoms by wearing $ChromaGen^{TM}$ lenses. Methods: After wearing the $ChromaGen^{TM}$ lens for 3 months, the dyslexia symptoms corrective lens, 52 students who had suspected symptom of dyslexia were asked questions, and we measured the improvement degree of reading ability of the student. Results: The $ChromaGen^{TM}$ wearer read 110.26${\pm}$22.07 words in 1 minute, and naked yeses or glass wearing students read 106.42${\pm}$22.70 words. Reading ability of the student having suspected symptom of dyslexia were measured after wearing $ChromaGen^{TM}$ for 3 months. The results showed improvement reading ability of 3.70${\pm}$0.29 (p=0.01, t=2.26), 4.50%${\pm}$0.10 (p=0.01, t=2.78) for $ChromaGen^{TM}$ wearer with statistical difference. A survey on the satisfaction of reading improvement with wearing $ChromaGen^{TM}$ showed that 88.4% of questioned person answered wearing $ChromaGen^{TM}$ had improved their dyslexia symptoms. Conclusions: With statisical significance (p<0.05). this study suggests that $ChromaGen^{TM}$ lens has an effect on improving reading speed of dyslexia patient. We know from these results that the $ChromaGen^{TM}$ lens which is used to dyslexia had an effect to improvement of reading speed for dyslexia. And the results of this study is statistically different (p<0.05).

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.69-84
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• 1993

In order to determine the optimum operational paramsters in cow manure composting, 4 laboratory scale composters were established. The cow manure was mixed with certain amount of saw dust to adjust the initial C/N ratio to 24, initial pH to 6.9 and composting was performed with varying operational conditions. It was found that the optimum aeration rate was 1000 ml/min kg. VS, the optimum moisture content 50% and no significant difference was found with different initial pH condition. Microorganisms were counted under the optimum conditions determined in this study. At the end of the experimental period, the number of bacteria, actinomycetes and fungi was $1.5{\times}10^9$ cells, $1.1{\times}10^8$ cells and $3.0{\times}10^8$ cells/g dry compost, respectively. At day 0, the number of coliforms, fecal coliforms and fecal streptococci was $3.1{\times}10^3$ cells, $7.5{\times}10^2$ cells and $5.6{\times}103$ cells/g dry composting material, respectively. Their population was decreased with time lapse, However, their survival time was longer than those reported by other researchers. Microorganisms were identified at the end of the experiment. Genus Bacillus was the most dominant comprising 89.3% of the total population. Among the Genus Bacillus, B. circulans compoex was the most abundant, followed by B. Stearothermophilus, B. Sphericus, B. licheniformis and B, brevis.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.331-337
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• 2014

Purpose: This is a comparative experimental study on the amount of phoria by the removal time of binocular fusion. In this study, three tests were used for phoria test like Howell test, Thorington test and developed 3D polarizing test. Methods: In this study, it was considered the removal time of binocular fusion for measuring phoria. The three methods were used for measuring quantity of phoria: Howell test, Thorington test and developed 3D Polarizing test. The measurements progressed quickly to avoid eye-strain. So we designed the test charts for marking 3D display modules and the apparatus inserted lenses, like Maddox lens and prism, which are compatible with three phoria tests. The phoria at the moment separation was measured when the binocular fusion was broken through the apparatus and the that at the stable separation was measured when activity of the separated two images like indicated box and figure on horizontal axis stopped. Results: There were statistically significant difference between quantity of phoria at moment separation and that at stable separation. Amount of phoria at moment separation was relatively larger than amount of that at stable separation. In result in exophoria, the quantity of phoria at moment separation was higher than that at stable separation, and in phoria measured by developed 3D polarizing test, it shows the similar results at two condition. Conclusions: For exophoria, the amount of phoria at moment separation of binocular fusion was relatively larger than that at stable separation. The amount of difference between phoria values at moment separation and that at stable separation was alike among three phoria tests. Usually in working, there is no distinction between moment separation and stable separation. But there were definitely the difference between two ways to separate binocular fusion. Therefore, it is need for writing on prescription test name for measuring phoria and condition of separation of binocular fusion.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.1
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• pp.21-30
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• 2015

Bulguksa Temple, a typical temple of Silla was lost during Japanese Invasion of Korea and there are records of reconstructing in its record, Bulguksa Sajeok. There is no record after that. And reconstructing was stopped due to lack of money and repair works were conducted for two times in Japanese colonial era. First repair work was from 1989 to 1919 and second repair work was conducted from 1922 to 1925. After Liberation, Bulguksa Temple Restoration Committee was established in 1969 and the construction has started since 1970 after excavation investigation to complete in 1973. The shape of south arcade without walls in the main temple of Bulguksa was found in a blue print of Bulguksa in Japanese colonial era in National Archives of Korea now and a picture of Bulguksa in 1902 taken by Sekino Tadashi. It verified the correlation between Gupumyeonji which was discovered in restoration work in 1970s and a legend of Muyoungtap. And a stair from the hall of Paradise to the main temple was introduced as a stair including Pure Land Buddhism doctrine in many literature materials, but a blue print of Bulguksa in Japanese colonial era and reports of excavation investigation in 1970s verified that it was a temporary stair built by Japan and its meaning was given later. This research checked the scenery of Bulguksa Temple before Japanese colonial era and it is intended for basic data to conduct restoration or reconstruction project in the future.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.51-59
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• 2000

Objectives: It is been reported that sleep patterns change significantly during the adolescent years. In Korea, the sleep patterns of adolescents have not been investigated systematically. The authors performed preliminary study about sleep patterns of middle and high school students in Seoul before nationwide study. Methods: The authors selected one of middle and high schools located in typical middle class area in Seoul. The study was performed during the periods when examination or vacation did not affect the sleep cycle. Fifty to one hundred male and female students were selected from one school year each. One of investigators explained the purposes and methods of this study to the students and gave additional explanation to the teachers in charge. We designed a questionnaire for subjects to describe the nap time, bedtime, sleep latency, total sleep time, rise time and sleep efficiency, and the students recorded sleep logs for seven days including weekend. Eight hundred three students answered the questionnaires. Among them, we selected the subjects who recorded sleep logs at least three days and filled up the questionnaires completely. Finally, seven hundred seventy one subjects were included in this study. Weekend was defined as the time from Saturday morning to Sunday morning, and Sunday sleep patterns were treated separately. Results: Across the six school years, school-night bedtimes were delayed one hundred twenty four minutes and school-ight rise times were advanced by thirty five minutes. School-night total sleep times were decreased by one hundred fifty eight minutes, and weekend bedtimes were delayed by one hundred twenty five minutes. The students tended to oversleep on weekends, and the mean of weekend oversleep was ninety six minutes. But, bedtime in weekends was not delayed. Daytime sleep, sleep latency and sleep efficiency were not changed greatly across six school years. Total sleep time of female students was decreased significantly between third middle school year and first high school year, but time of male students was decreased between first and second high school year. Conclusion: It is supposed that sleep deficiency of middle and high school students in Seoul was due to delayed bedtimes and advanced rise times across the school years.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.212-222
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• 2013

We studied the eating habits and sleeping patterns of 682 middle and high school students in their third year in Gwangju. According to the body mass index (BMI) of the subjects, obesity (over weight) was significantly higher in the third graders of high school students ($20.8{\pm}4.0$, 32.9%) than middle school students ($19.4{\pm}3.8$, 14.2%) (p<0.001). In addition, 71.1% of high school students experienced a lack of sleep compared to 48.8% of middle school students (p<0.001). There was a difference between good and bad sleepers in the number of times they ate snacks and the quantity of their snacks. Good sleepers had more fruit and dairy products (e.g. fruit juice 2~4 times (p<0.05), milk 2~4 times (p<0.001), apples 2~4 times, strawberries 2~4 times (p<0.01), and bananas 2~4 times a week), while bad sleepers consumed more beverages, frozen desserts, flour-based foods, fast food, bread, and rice cake. Bad sleepers clearly consumed snacks more frequently. From analyzing the correlations between sleep quality and snack intake, eating fruits 2~4 times a week (30 g~200 g/once) and drinking dairy products 2~4 times a week (120 mL~400 mL/once) appears to promote better sleeping habits.

• Journal of Mushroom
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• v.2 no.2
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• pp.76-87
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• 2004

This experiments were conducted to study on the economic analysis of Phellinus spp.(Comercial name: Sanghwang mushroom). These results were as follows: Phellinus spp. can be cultivated about 4 years by one time inoculation. This mushroom has been cultivated by the method of burying log into the soil(BM) at the first time. Recently, however, the method of hanging log on the shelves in the house(HM) is used, because HM has more advantage than BM that HM can be cultivated more pieces of logs than BM. On the other hand, HM is required to invest more 5,678,230Won for the equipments than the BM. And also, HM is required 14,400 pieces(2.8 times) more log numbers than BM 5,000 pieces. Also, HM is required more 3,680,000Won to purchase log, 1,104,000Won to purchase spawn. The cost of production is required to 20,180,971Won for BM, and 37,953,825Won for HM. Accordingly, product cost of HM is 1.9 times higher than BM. The operating cost is required to 1,207,712Won for BM, and 24,075,432Won for HM. Accordingly, operating cost of HM is 2.0 times higher than BM. The net income is 580,940,000Won for BM, and 1,683,300,000Won for HM. Accordingly, net income of HM is 2.9 times higher than BM. The income is 589,040,000Won for BM, and 169,718,000Won for HM. Accordingly, income of HM is 2.9 times higher than BM. In conclusion, HM is required 2.8 times more logs. HM has 1.03 times more products per a piece of log. HM has 1.9 times more production cost, and 2.0 times more operating cost. As you read above, HM and BM have two different aspects. BM is required less investment cost than HM, but BM has lower income because of the different capacity of production. By the comparing those two methods, HM is resulted more efficient method for the producing mushroom. Only in the side of cash flowing, the cash expenditure of BM is required less money at first year. But it has no production at first year. BM would get the income after 2 years buring the logs. The cash expenditure of HM is required much money for the equipments and the logs at first year, but HM would get the income at first year.

• Progress in Medical Physics
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• v.9 no.1
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• pp.11-21
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• 1998

Circular metal electrodes were vacuum-deposited with chromium on the both sides of Teflon-FEP and PET film characteristic of electret and the physical properties of the two polymers were observed during an irradiation by gamma-ray from $\^$60/Co. With the onset of irradiation of output 25.0 cGy/min the induced current increased rapidly for 2 sec, reached a maximum, and subsequently decreased. A steady-state induced current was reached about in 60 second. The dielectric constant and conductivity of Teflon-FEP were changed from 2.15 to 18.0 and from l${\times}$l0$\^$-17/ to 1.57${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/, respectively. For PET the dielectric constant was changed from 3 to 18.3 and the conductivity from 10$\^$-17/ to 1.65${\times}$10$\^$-13/ $\Omega$-$\^$-1/cm$\^$-1/. The increase of the radiation-induced steady state current I$\^$c/, permittivity $\varepsilon$ and conductivity $\sigma$ with output(4.0 cGy/min, 8.5 cGy/min, 15.6 cGy/min, 19.3 cGy/min) was observed. A series of independent measurements were also performed to evaluate reproducibility and revealed less than 1% deviation in a day and 3% deviation in a long term. Charge and current showed the dependence on the interval between measurements, the smaller the interval was, the bigger the difference between initial reading and next reading was. At least in 20 minutes of next reading reached an initial value. It may indicate that the polymers were exhibiting an electret state for a while. These results can be explained by the internal polarization associated with the production of electron-hole pairs by secondary electrons, the change of conductivity and the equilibrium due to recombination etc. Heating to the sample made the reading value increase in a short time, it may be interpreted that the internal polarization was released due to heating and it contributed the number of charge carriers to increase when the samples was again irradiated. The linearity and reproducibility of the samples with the applied voltage and absorbed dose and a large amount of charge measured per unit volume compared with the other chambers give the feasibility of a radiation detector and make it possible to reduce the volume of a detector.