• Journal of Chest Surgery
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• v.22 no.2
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• pp.246-255
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• 1989

A total and consecutive 291 patients of isolated single mitral valve replacement using the Ionescu-Shiley bovine pericardial xenograft valve operated on between October 1978 and June 1983 were retrospectively studied for the durability of the substitute valves based on the structural degeneration of primary tissue failure which had been proved on their re-replacement surgery. The mean age at the initial surgery was 32.4*12.5 years, and the operative mortality rate was 5.2 %. The early survivors of 276 patients were followed up for a total 1148.3 patient-years[mean\ulcornerD, 4.16*2.57 years]at the follow-up end of June 1988. They experienced 4 major late complications: 1.045 % thromboembolism/patient-year [pt-yr]; 0.871 % bleeding/pt-yr; 0.610% endocarditis/pt-yr; and 3.309% overall valve failure/pt-yr or 1.655% primary tissue failure/pt-yr. The actuarial survival rates were 89.4*2.2% and 87.7*2.5% at 5 and 10 years after initial surgery respectively. The probabilities of freedom from thromboembolism were 95.1*1.6% and 93.2*2.0% at 5 and 10 years after surgery. Nineteen patients underwent re-replacement of the Ionescu-Shiley valve because of primary tissue failure, and there was no operative mortality. The incidence of primary tissue failure was highest for the patients less than 15 years of age occurring in 9 out of 27 patients [33.3 %] or 8.68 %/pt-yr, while it was 4.0 % or 0.96 %/pt-yr for the rest of patients older than this age. The probabilities of freedom from primary tissue failure were 96.7*1.4 % and 84.2*3.8% at 5 and 9 years after surgery. The freedom from tissue failure increased as the age limits of cumulative younger patients were increased while it decreased as the age limits of cumulative older patients were decreased. Although it is clear that the Ionescu-Shiley valve would degenerate prematurely in young patients, the definite age limit could not be identified when the risk of early failure was significantly high.

• Journal of Chest Surgery
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• v.19 no.1
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• pp.108-115
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• 1986

During 12 years period from 1974 to 1985, 76 valve replacement procedures were performed at Seoul National University Hospital in 67 pediatric patients aging up to 15 years [mean 12.3 years] and it was 7.3% of total valve replacement procedures in same period. Sixty seven patients were composed of 44 males and 23 females. Of the 67 patients, 43 patients had acquired valve lesions and 24 patients congenital valve lesions. Sixty cases received single valve replacement, 7 cases double or triple valve replacement and 9 cases redo-valve replacement. Sixty seven patients received 84 valves [65 bioprosthetic valves and 19 prosthetic valves by] 76 operations, Sixty three of 65 bioprosthetic valves had been replaced before 1983 and 15 of 19 prosthetic valves in recent 2 years. Eleven patients [14.6%] died within one month post-operatively and 8 patients [10.5%] during the follow-up period with the overall mortality rate of 25.1%. There were early post-operative complication of 23 cases [30.3%] and late post-operative complication of 27 cases [35.3%] with the total complication rate of 65.8%. In 58 patients received bioprosthetic valves, there were 14 cases of restenosis of replaced valves. Of the 14 cases of bioprosthetic valve restenosis, 8 cases received redo-valve replacement procedures without mortality in 1 5/12-5 years after initial operation but 4 cases died without reoperation and 2 cases lost during follow-up. The overall mortality and complication rate were still high but they markedly decreased during recent 2 years. So, in spite of its containing many problems, valve replacement in children is becoming safe and useful procedure in whom valve reconstructive procedures are impossible.

• Journal of Technologic Dentistry
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• v.20 no.1
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• pp.27-35
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• 1998

There is not yet 4 years college education coursed for producing dental technicians in Korea. At present only 3 years college courses are provided for producing dental technicians. This is undesirable in that lots of professional vacations have been more and more speciallized by establishing 4 years college courses. To improve and elevate the ability of dental technicians. the establishment of more advanced educational courses, for example promoting present 3 years college courses to 4 years college courses, is urgently needed. This necessity become more evident when we take into account the ever increasing social demand for dental technicians.

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.173-179
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• 2000

Recent changes in the coastal sea surface temperatures (SST) in Korea are studied by time series analysis of daily SST data during the last 60 years (1936-1995) at 18 coastal observation stations of the National Fisheries Research and Development Institute. The climate of coastal SST in Korea are rapidly changing in recent years. General trends of coast SST changes in Korea are as follows. The annual averages of SST are increasing. The annual ranges of SST variation are decreasing. The winter SST are increasing while the summer SST have a decreasing tendency. Climatic changes in coastal SST in recent 30 years (1965-1995) are more pronounced than those in the last 60 years (1936-1995). The observed trend of coast SST implies that the climate in Korea shows a tendency to shift from temperate zone to subtropical zone.

• Journal of Korean Clinical Health Science
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• v.4 no.4
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• pp.762-768
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• 2016

Purpose. This study was performed on survey related optician's perception of NCS and required jobs to develop curriculum of department of ophthalmic optics Methods. This study was to evaluate the questionnaire survey of 63 opticians working in Optometrist in Daegu Metropolitan City from November 1, 2016 to November 18, 2016. Results. As for the opticians who know about NCS, 23.8% of the respondents answered that the opticians' perception of NCS is very low. For the four required jobs of the technical part, less than 5 years of optometrists ; optometry 73.7% > fitting 47.4% > ophthalmic dispensing 36.8% > lensmeter 5.3%, more than 5 years and less than 10 years of optometrists ; optometry 84.6% > fitting 53.8% > lensmeter 46.2% > ophthalmic dispensing 38.5%, more than 10 years of optometrists ; optometry 67.7% > ophthalmic dispensing 51.4% > lensmeter 19.4% > fitting 16.1%. For the four required jobs of the management, less than 5 years of optometrists ; product 57.9% > service 47.4% > manners 10.6% > sales 5.3%, more than 5 years and less than 10 years of optometrists ; service 76.9% > product 53.9% > manners 46.2% > sales 38.5%, more than 10 years of optometrists ; service 45.2% > manners 42.0% > product 32.3% > sales 19.4%. Conclusions. Although there were 108 required jobs of the technical part and 94 required jobs of the management part, the technical level of the department of ophthalmic optics was satisfactory, but the classes of the management part were insufficient. It will be necessary to actively reflect the needs of industry through curriculums reform.

• Asian Journal of Turfgrass Science
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• v.10 no.4
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• pp.305-313
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• 1996

This study was carried out to investigate the removal rates of Cd and Pb of the litters in the Phragmites communis. Miscanthus sacchariflorus, Typha angustata, Scirpus tabernaemontani grassland aquatic ecosystem in the lake Paldangho. The annual production of Cd and Pb were 0.005g /$m^2$ , 0.21g /$m^2$in P. commumis, 0.004g /$m^2$, O.08g /$m^2$ in M. sacchariflorus, 0.023g /$m^2$, 0.42g /$m^2$ in T. angustata and 0.020g /$m^2$, 0.23g /$m^2$ in S. tabernaemontani respectively. The removal rates of Cd and Pb of the litters were 0.83, 0.85 in P. communis. 0.36, 0.54 in M. sacchariflorus, 0.61, 0.51 in T. angustata and 0.76, 0.71 in S. tabernaemontani, respectively. The times required to decay 50, 95, 99 percent of the steady state level and turnover values of cadmium on the grassland floor were 0.83, 3,60, 6.00 years in P. communis. 1.90, 8.24, 13.74 years in M.sacchariflorus, 1.15, 4.96, 8.27 years in T. angustata and 0.91, 3.95, 6.58 years in S. tabernaemontani The times required to decay 50, 95, 99 percent of the steady state level and turnover values of lead on the grassland floor were 0.81, 3.51, 5.86 years in P. communis. 1.28, 5.56, 9.26 years in M. sacchariflorus, 1.37, 5.94, 9.90 years in T. angustata and 0.97, 4.21, 7.02 years in S. tabernaemontani. Key words: Removal rate, Accumulation, Paldangho, Cadmium, Lead, Phragmites communis Miseanthus sacchariflorus, Typha angustata, Scirpus tabernaemontani.

• Journal of Practical Agriculture & Fisheries Research
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• v.19 no.1
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• pp.129-137
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• 2017

This study was conducted to investigate of growth performances and net assimilation rate(NAR) of Allium microdictyon Prokh. distributed inland and Allium ochotense Prokh. originated Ulleung-do. The Allium microdictyon on the growth of 1-2 years showed the largest relative growth rate, and showed high relative growth from three to four years. Allium ochotense on the growth from one year to three years showed high relative growth rate. The T/R rate of Allium ochotense of 2~5years was in the range of 0.4~0.5. However, The T/R rate of Allium microdictyon was increased as increasing with age. This implies that Allium microdictyon was consumed more energy on growing subterranean part. The LWR of 1~3years old Allium ochotense. was showed more smaller than 4~5years old. It seems that the growth characteristics of Allium ochotense 1-3 years after sowing the leaf growth consume more energy than Allium microdictyon. Net assimilation rate(NAR) of Allium ochotense for 1-3 years after sowing was higher than that of Allium microdictyon. In this time, the material of Allium ochotense has a higher production efficiency can be seen indirectly.

• Magazine of the Korean Society of Agricultural Engineers
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• v.23 no.2
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• pp.45-53
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• 1981

Long term precipitation gaging station record (58 years) was analyzed by progressive mean method to compare the estimated effective period of records for computing mean and probable values. Obtained results are as follows: 1. Fifty-eight years precipitation records at Jinju, Gyeong Sang Nam Do was analyzed by double mass analysis method. Result was appeared that the record was consistent with time. 2. The effective period of records for estimating mean values with the departure of 5% or less from the true mean are up to 33 years for annual precipitation, 20 years for annual maximum daily precipitation and 45 years for maximum successive dry days in summer season. 3. To estimate the probable values by Gumbel-Chow method within the departure of 5% level from true value, periods of 51 years, 38 years and 45 years were required for annual precipitation, annual maximum daily precipitation and maximum successive dry days in summer season, respectively.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.980-989
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• 1989

The Hancock porcine xenograft valves had been used in Seoul National University Hospital, mainly because of their antithrombogenicity despite of the predicted failure, from March 1976 to April 1984, and a total and consecutive 163 patients were retrospectively studied for late results with the special stress on the structural failure. The hospital mortality rate [within 30 days] was 6.1 %, and the 153 early survivors were followed up for a total of 822.9 patient-years [p-y][Mean * SD 5.38 * 3.02 years]. The linealized late mortality was 1.823%/p-y. Four major complications related to the Hancock valve were: 1.822% thromboembolism/p-y; 0.729 % bleeding/p-y; 0.972% endocarditis/p-y; 3.646% overall valve failure/p-y and 2.187 % primary tissue failure [PTF]/p-y. The actuarial survival rates at 5 and 10 years were 94.90 * 1.89% and 80.58 * 5.21 %; and the probabilities of freedom from thromboembolism at 5 and 10 years were 90.93 * 2.63% and 83.35 * 7.64 9o respectively. The probabilities from PTF at 5, 10 and 12 years were 98.02 * 1.39%, 60.62 * 8.89% and 49.60 * 12.34 %. One hundred-eighteen patients [72.4%] had single MVR [age, 34.0 * 10.9 years] with the operative mortality rate of 4.2%; and 113 early survivors were followed up for a total 616.4 patient-years[5.46 * 2.96 years]. The late mortality rate was 1.460 %/p-y. The major complications were: 1.622 % thromboembolism /p-y; 0.487% bleeding/p-y; 0.649 % endocarditis/p-y; 2.920% primary valve failure/p y and 1.785% PTF/p-y. The actuarial survival rates were 97.08 * 1.67%[at 5 years] and 81.27 * 6.64%[at 10 years], and the probabilities of freedom from thromboembolism 92.44 * 2.76 %[at 5 years] and 80.89 * 11.08%[at 10 years]. The probabilities of freedom from PTF at 5 and 10 years were 98 70 * 1.29% and 65.59 * 9.78% respectively. The mean age of 11 patients of PTF was 25.7 * 8.8 years and the valve extraction period 7.16 * 1.45 years. Failure of bioprosthetic xenograft valves are reportedly known to occur earlier in young patients in an accelerated fashion. The study with two groups divided into the cumulative younger and the cumulative older patients according to the age limits of 5-year interval strongly suggested these tendency. Although PTF began to occur past postoperative 5 years and the probabilities of freedom from PTF increased as the age limits raised and the number of patients increased in the cumulative younger patients while they decreased as the age limits lowered and the number of patients increased in the cumulative older patients, the definite age limits from which the Hancock valve can be safely recommended could not be obtained. From the results, the Hancock valves are contraindicated in patients younger than 20 to 25 years and may be safely recommended in patients older than 45 years as a tentative conclusion. Further longitudinal study may define these age factors.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.76-84
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• 2022

The study was conducted to analyze the impacts of COVID-19 on the number of dental trauma patients. Based on the data provided by the Health Insurance Review and Assessment Service's Healthcare Bigdata Hub, dental trauma which occurred from 2010 to 2020 was analyzed. Since the outbreak of COVID-19, the incidence of dental trauma per 100,000 decreased compared to the average Incidence between 2017 to 2019. By age, it decreased by 5.4% (p = 0.017) for 0 - 4 years old, 30.3% (p < 0.001) for 5 - 9 years old, 39.5% (p < 0.001) for 10 - 14 years old, 14.5% (p = 0.002) for 15 - 19 years old, 1.3% for 20 - 29 years old, 0.2% for 40 - 49 years old, 2.7% for 50 - 59 years old, 1.2% for 60 years old or older, but it increased by 2.5% for 30 - 39 years old. Compared monthly, before and after the outbreak of COVID-19 confirmed patients, the number of dental trauma patients dropped sharply. After the outbreak of COVID-19, the incidence of dental trauma decreased significantly for under 20 years old, but the decrease was not significant for 20 years old or older.