• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.1-8
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• 2022

Purpose: The purpose of this study was to evaluate the effects of mouthwash containing sodium chloride on dental plaque, gingival inflammation index, and bad breath through clinical trials. Materials and Methods: This trial was designed as 12 weeks and subjects were instructed to put an appropriate amount of the provided standard detergent on a toothbrush and brush their teeth 3 times a day. They were instructed to gargle a mouthwash provided to each group after brushiung. Efficacy was evaluated by performing gingival and periodontal-related index tests, dental plaque changes, and bad breath tests a total of 5 times. All data were statistically analyzed using 2-sample t-test, paired t-test to compare between groups at 95% significance level using IBM SPSS Statistics 24.0. Results: As a result of the PMA index measurement, the gingivitis improvement effect rate of the experimental group compared to the control group was 107.63% after 8 weeks and 73.08% after 12 weeks. As a result of the PHP index measurement, the plaque improvement effect rate of the experimental group compared to the control group was 79.37% after 8 weeks and 74.06% after 12 weeks. As a result of measuring volatile sulfur compounds using Oral Chroma, the effectiveness of improvement in bad breath in the experimental group was 65.06% after 8 weeks and 99.33% after 12 weeks, compared to the control group. Conclusion: As a result of this study, it was confirmed that effective gingivitis alleviation, plaque removal effect and bad breath removal effect can be expected when a mouthwash containing sodium chloride, green tea extract, and sodium monofluorophosphate is used.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.268-289
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• 2013

The Dinosaur tracksite at Jeori, Geumseongmyeon, Euiseonggun, Gyeongsangbukdo, Korea (National Monument No. 373) has been studied in the aspects of location, stratigraphy, sedimentology, fossil occurrence, unique geological records, literature, significance in natural history, preservation, and management. On the basis of these features, the Jeori tracksite has been assessed semiquantitavely. The Jeori tracksite occurs in the Sagok Formation (Albian) of the Euiseong sub-basin, and over 300 footprints forming 12 sauropod trackways, 10 ornithopod trackways, and 1 theropod trackways are preserved in this tracksite. The track-bearing deposits consist of tabular-bedded medium- to fine-grained arkose with mudstone drape, interlaminated fine-grained sandstone to siltstone and mudstone, and shaly mudstone. The dinosaur tracks are preserved in the interlaminated fine-grained sandstone to siltstone and mudstone, and most of them are observed as underprints. The track-bearing deposits are interpreted as sheetflood deposits on the floodplain under a seasonal paleoclimatic condition with alternating of wetting and drying periods. Multiple tension fractures with NE strike were formed in the track-bearing bed, which resulted in that tracks seem to occur in several horizons. The significance in natural history of the tracksite can be summarized as follows: 1) the historical implication of the Jeori tracksite as the firstly designated National Monument of dinosaur fossil sites, 2) the high density of the occurrence of diverse footprints (over 300) within small area (about $1,600m^2$), and 3) the significance of the tension fractures associated with the track-bearing bed as geoeducational records for the understanding the development of fault. In order to share the value of the Jeori tracksite in the aspect of natural history with the community and public, the interpretive panel should be modified to include figures explaining paleoenvironment and tension fault development. In addition it is recommended that a brochure be published briefly explaining the tracksite and to educate the residents about the natural and social significance of the tracksite. For the safety of visitors it would be desirable for the road in front of the tracksite to be moved at least 10 m southward, which could mitigate the shaking of the track bed caused by traffic.

• Korean Journal of Plant Resources
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• v.36 no.2
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• pp.107-121
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• 2023

This study analyzed the polyphenol, flavonoid contents, antioxidant activity, anti-aging activity and phenol component contents of Saccharina japonica (SJ), Costaria costata (CC) extracts with hot water, 95% methanol, 95% prethanol for investigating possible utilization of SJ and CC extracts. The result revealed that the SJ and CC methanol extracts showed the highest polyphenol and flavonoid contents, 4.63 mg TAN/g, and 4.19 mg QUE/g respectively. Also, the SJ and CC methanol extracts showed higher antioxidant activity than prethanol and hot water extracts, whereas the ABTS radical scavenging activities were the highest in prethanol extracts (IC₅₀ = 15.4, 10.3 ㎍/µL). In anti-aging activity for evaluating the anti-wrinkle activity and skin whitening activity, the CC methanol extracts had high collagenase inhibitory activity (88.3%), and the SJ prethanol extracts showed higher elastase inhibitory activity (19.0%) compared to other extracts. Then the tyrosinase inhibitory activity was significantly higher in the SJ and CC methanol extracts (41.8, 30.3%, respectively), whereas prethanol extracts were the lowest. To identify the phenol component contents of SJ and CC extracts, 4-hydroxybenzoic acid, naringenin, naringin and nicotinic acid were measured using LC-MS/MS. As a result, the phenol contents were the highest in SJ methanol extract (4-hydroxybenzoic acid), SJ and CC prethanol extract (naringin and naringenin) and CC prethanol extract (nicotinic acid). Lastly, the antioxidant activity of SJ and CC showed high correlations with polyphenol and flavonoid contents (R = -0.946~0.883). These results suggest that prethanol or methanol extracts of SJ and CC have higher antioxidant activities, anti-aging activity and the potential to be used as material for health functional food and cosmetics.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.175-183
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• 2000

The purpose of this study was to identify the compensatory adaptation of dentoalveolar structure according to the various skeletal relation through the statistical correlation between the anteroposterior, vertical skeletal and dentoalveolar relation. For this study, the sample were consisted of 101 adult subjects (51male and 50 female, mean age; male 23.6 years, female 21.5 years) who had good occlusion with the range of normal overjet and overbite and acceptable Angle's class I molar relationship which had not been related orthodontically The results were as follows : 1. Even though acceptable normal occlusion, the range of measurements which represent anteroposterior, vertical skeletal relation and dentoalveolar relation were very wide. 2. Upper and lower incisor axis were significantly correlated with anteroposterior skeletal relation, which means the mote lingual inclination of upper anterior teeth and the more labial inclination of lower anterior teeth according to the more anterior position of mandible to the maxilla (P<0.01). 3. Upper and 1ower anterior alveolar bone height was statistically correlated with the lower anterior vertical skeletal height. 4. Upper and 1ower alveolar bone height were not correlated with anteroposterior skeletal relation (P>0.05). 5. The correlation between the incisor axis and vertical skeletal was more closely related in upper anterior teeth than the lower anterior teeth. To summarize the above results, even though acceptable normal occlusion, skeletal and dentoalveolar relation was very widely ranged, and there were close relationship between the anteroposterior skeletal relation and the inclination of upper and lower anterior teeth and between the vertical skeletal relation and upper and lower anterior alveolar bone height. These finding can be concluded as compensatory adaptation to the different skeletal relationship.

• Journal of Korean Society of Forest Science
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• v.66 no.1
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• pp.37-44
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• 1984

The study was carried out to investigate the relationship of certain socio-economic factors to the private owner's knowledge of forestry practices. The dependent variable was knowledge level in forestry, and the six independent variables were owner's age, educational level, forestland area, socio-economic status, communication and socio-psychological factors. For the study the data were collected by interviewing 258 private forest owners, and analized primarily by multiple correlation statistical technique. The sampled private owners were grouped into two categories: the common owners and model owners. 1) The average score of forestry knowledge of common owners was lower than that of model owners, and the difference was about 15 scores. The scores of other independent variables such as age, educational level, forestland area, socio-economic status, communication and socio-psychological factors of common owners were also significantly lower than those of model owners. 2) The common owner's knowledge of forestry practice were positively correlated with educational level, socio-psychological and communication variables. On the other hand, the model owner's were negatively correlated with the educational level, but positively with the socio-economic status and the socio-psychological variables. 3) The multiple correlation coefficient between the common owner's knowledge scores and six independent variables was 0.5667. About 31.46 percent of the variance of this knowledge could be explained by the communication variable, and other 1.42 percent by the socio-psychological factor. In the case of model owners, the multiple correlation was 0.5332, and about 16.62 percent of the variance of the knowledge could be explained by the communication variable, and ls.y percent by the socio-psychological factor. 4) The opportunity of communication contact through the mass media, personal communication and owner's social participation should be augmented for the effective forestry extension works, because it is one of the results of the study that the private forest owner's knowledge in forestry was greatly affected by communication variable.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.463-471
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• 2017

The purpose of this study was to examine the causes of career interruptions among dental hygienists, institutional measures required for their long service and ways of creating a stable employment culture for them in determine how to resolve labor shortage, create stable jobs, and step up the reemployment of idle manpower. In addition, the following suggestions are made for the establishment of a stable employment culture for dental hygienists by analyzing related literature, research materials, and information such as forums for establishing appropriate jobs for female dental workers. First, a system should be set up to prevent career interruption among dental hygienists. The work environment should be improved to prevent career breaks, and the wages, working hours, and working style should be efficiently structured to maintain the tenure of employees. Second, a plan should be devised to make use of idle manpower, and a variety of necessary programs should be developed. With respect to regular working hours, the time conversion system should be used, which reduces the amount of time one would want to work while receiving a national subsidy. Third, dental hygienists working in different occupations for marriage, childbirth, childcare, school and personal hygiene should make a way to return to the dental system immediately when they want. Fourth, the government should take institutional measures and offer down-to-earth support and benefits for women consideration their social characteristics to guarantee a balance between work and childcare.

• Journal of dental hygiene science
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• v.12 no.3
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• pp.235-243
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• 2012

The purpose of this study was to examine the oral symptoms, self-rated systemic health state and oral health status of industrial workers in a bid to provide some information on oral health education geared toward industrial workers. The subjects in this study were 294 workers who got a medical checkup in Korea Industrial Health Association in North Gyeongsang Province. Those who felt less inconveniences in the oral cavity led a better quality of life related to oral health in every area except physical handicaps (p<.001, p<.01). The men's OHIP-14 was higher than the women's, and the younger workers led a better quality of life related to oral health in the area of social separation(p<.01), and the married ones did in the area of physical handicaps, mental disorder and social separation(p<.05). And the workers whose household income was larger lived a better quality of life related to oral health in the areas of Psychological discomfort, physical handicaps, mental disorder, social disorder and social separation(p<.05). Those who found themselves to be generally in good health(p<.001, p<.05) and whose subjective oral health state was led a better quality of life in every area(p<.001, p<.05). The findings of the study showed that there were differences in the quality of life according to awareness of oral symptoms, general health status and oral health state.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.439-443
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• 2010

The purpose of this study was to prevent excessive use of fluorine toothpaste. To comparatively evaluate the amount used of the fluorine toothpaste in children from 3 to 6 years old, the toothpaste amount was compared according to toothbrush size and toothpaste squeezing method targeting 84 children in 5 child care centers where were located in Hongseong-gun, Chungnam. The toothpaste amount was compared with a method of squeezing to pea-size and a method of smear on toothbrush, targeting 141 students for the Dept. of Dental Hygiene, who are actually carrying out oral health education to targeting children. The statistical analysis was used SPSS 14.0 K for Windows program(Copyright(c) SPSS Inc.). The following results were obtained. 1. The amount of fluorine toothpaste squeezed on toothbrush for children was 0.29 g. The amount of fluorine toothpaste squeezed on toothbrush for adults was 0.34 g. It was surveyed to use the less amount of toothpaste when squeezing to smaller toothbrush (p<0.05). 2. The amount that children aged 3-6 squeezed as the method of squeezing commonly at ordinary times was 0.31g. The amount that was squeezing to pea-size was 0.21 g. The amount that was squeezed by using smear method was measured to be 0.26g. Less amount of fluorine toothpaste was used with the method of squeezing to pea-size and smear method rather than a method of squeezing commonly at ordinary times(p<0.05). 3. As a result of surveying the students of the department of dental hygiene, the amount of having squeezed to pea- size was 0.23 g. It was surveyed to be 0.15 g when having used the smear method. Thus, it was surveyed to use the less amount of toothpaste when using the smear method(p<0.05). 4. Using smaller toothbrush, the amount used of fluorine toothpaste can be reduced. Both smear method and the method of squeezing to pea-size are available for minimizing careless fluorine intake by less used amount of fluorine toothpaste.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.332-341
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• 2014

This study was aimed to define the predicting factor account for the Korean Dental Hygienist Licensing Examination (KDHLE) by analyzing the academic grade score and the KDHLE score. The subjects included 185 graduates (2007, 2009, 2011~2014 graduates). The ratio of successful applicants of the subjects was 99.2%. The academic grade scores were calculated to grade point average, the KDHLE was scoring marks out of 300 (200 of written examination score and 100 of performance evaluation score) for correlation and regression analysis. The graduation grades and comprehensive examination scores correlated significantly with the KDHLE written examination scores (correlation coefficient=0.612), and KDHLE total score (correlation coefficient=0.258). First~third grade score and comprehensive examination scores correlated significantly with KDHLE total scores (p<0.05). Especially, there are the highest correlated between second comprehensive examination scores and KDHLE total scores (correlation coefficient=0.455), the last score in time sequence is the important factors account for the KDHLE total score. But there is no correlation between academic grade score and KDHLE performance evaluation scores, therefore it is necessary to study for determine the reason. The results of multiple linear regression analysis, second grade score and the average score of comprehensive examination were the main predicting factors account for the KDHLE total score, the explanatory power was 31.6%. Our results show that KDHLE total and written examination scores are predicted by the academic grade score reliably, but not the KDHLE performance evaluation scores. Further studies are needed to determine relationship between dental hygiene education and KDHLE.

• Journal for History of Mathematics
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• v.22 no.2
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• pp.27-52
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• 2009

This article discusses the contributions of the leader Oswald Veblen, who was the president of AMS during 1923-1924. In 2006, Korea ranked 12th in SCIE publications in mathematics, more than doubling its publications in less than 10 years, a successful model for a country with relatively short history of modern mathematical research. Now there are 192 four-year universities in Korea. Some 42 of these universities have Ph.D. granting graduate programs in mathematics and/or mathematical education in Korea. Rapid growth is observed over a broad spectrum including a phenomenal performance surge in International Mathematical Olympiad. Western mathematics was first introduced in Korea in the 17th century, but real significant mathematical contributions by Korean mathematicians in modern mathematics were not much known yet to the world. Surprisingly there is no Korean mathematician who could be found in MaC Tutor History Birthplace Map. We are at the time, to have a clear vision and leadership for the 21st century. Even with the above achievement, Korean mathematical community has had obstacles in funding. Many people thinks that mathematical research can be done without funding rather unlike other science subjects, even though they agree fundamental mathematical research is very important. We found that the experience of early American mathematical community can help us to give a vision and role model for Korean mathematical community. When we read the AMS Notice article 'The Vision, Insight, and Influence of Oswald Veblen' by Steve Batterson, it answers many of our questions on the development of American mathematics in early 20th century. We would like to share the story and analyze its meaning for the development of Korean Mathematics of 21st century.