• Journal of Life Science
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• v.31 no.12
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• pp.1072-1078
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• 2021

The oral pathogen Streptococcus mutans is considered a major causative agent of dental caries in humans. The use of dental hygiene products, including toothpaste and mouthwash, is used for caries control. However, food intake can lead to the recurrence of oral microorganisms. This study aimed to explore why this bacterium dies so quickly during prolonged incubation and to assess whether this growth characteristic is closely associated with the secretion of metabolic products. Notably, the number of live S. mutans cells rapidly declined after 24 hr during the entire period tested, whereas the number of Escherichia coli cells, an indicator strain, remained steady over the same period. To test whether the S. mutans supernatants contained possible signals that accelerated the death of neighbor cells, we obtained the individual supernatants at the above time points. Following pH neutralization, the cells in which the supernatant was supplemented with glucose grew well. However, pH adjustment alone could not fully recover cell growth in conditions in which the supernatant was supplemented, with or without glucose. These phenotypes of S. mutans may be associated with signaling, not only resulting from nutrient depletion. The findings on the survival phenotype of S. mutans provide new insights into cell-cell communication in the biology of this bacterium.

• Journal of Ginseng Culture
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• v.6
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• pp.80-104
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• 2024

Ginseng, a representative medicinal plant of South Korea, is also highly valued in North Korea. However, due to limited access to information about North Korea, the actual cultivation, research and development trends, and related industry status of ginseng in North Korea are not well known. In this study, we aimed to understand the current status and research trends of the ginseng industry in North Korea based on limited available literature. In the North Korean pharmacopoeia, ginseng is referred to as "Koryo ginseng" and is defined as the roots of 6-year-old ginseng cultivated in the Kaesong region. The pharmacopoeia includes 22 types of ginseng preparations. In addition, 10 ginseng preparations are included in North Korea's Essential Drug List, and various health supplements, cosmetics, and toothpastes containing ginseng have been developed, distributed, and sold. Since 2014, the ginseng industry and research in North Korea have become more active overall. During this period, the ginseng cultivation area in Kaesong has been significantly expanded, and the facilities have been renovated. The Kaesong Koryo Ginseng Processing Plant has been equipped with sterilized, modernized facilities since 2016 and has been in operation. Since 2017, there has been a growing interest in quality control research, leading to the introduction of quality management regulations and certification systems in 2019. In the 1990s, there was significant research on ginseng product development, and since the 2000s, studies on the pharmacological effects and clinical research of ginseng have been reported. Additionally, research on ginseng cultivation and ginseng processing industries to increase yield has been emphasized. Ginseng, as a representative medicinal crop of Korea, holds great importance for both South and North Korea. Given its significance and the potential for synergy through mutual cooperation, ginseng serves as an ideal subject for inter-Korean exchange and collaboration.

• Journal of dental hygiene science
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• v.8 no.2
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• pp.81-87
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• 2008

The purpose of this study was to examine the oral health state, oral health awareness and oral health behavior of middle school students in a bid to raise concerns about oral health problems in a local community and help ensure the efficiency of oral health programs. The subjects in this study were 662 seventh graders in 14 different middle schools located in the city of Hwaseong. The findings of the study were as follows: Frist, In terms of indices related to dental caries, DMFT index numbered 2.0. Secondly, as to subjective oral health state, 22 percent of the boys and 10.9 percent of the girls found their own oral cavity to be healthy, and the gap between them and the others was statistically significant different(p=.000). Thirdly, in regard to tooth-related habits, the girls brushed their teeth more often than the boys(p=.000). Fourthly, for snack-intake habits, the largest number of the boys ate between meals once(42.1%), and the second largest group of them did it two or three times(31.3%). Fifthly, regarding how they felt about dental treatment, the greatest number of the boys and girls replied there's nothing special when they were asked about their mood in case of seeing a dentist next day. The second largest group answered they would get a little nervous. As to mood while waiting for treatment, the greatest number of the boys and girls answered they would get a little nervous. In regard to mood while lying on a dental chair, the largest group replied they would be nervous. Concerning mood while lying on a dental chair for scaling, most of them answered they would get nervous.

• Journal of dental hygiene science
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• v.5 no.2
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• pp.45-49
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• 2005

This study is designed to present basic materials necessary for offering the more effective way of dental hygienists, or those who are in charge of the education of Oral health, the treatment and prevention of dental problems, educating Oral health by stage by dint of determining the actual condition of the knowledge and management of dental hygiene, or prevention of the basic dental disease except the professional methods of dental management and evaluating their abilities to manage dental hygienes. In terms of the real conditions of the management of dental hygienes, the majority of the subjects said, "not bad" or "healthy". Most of them (62.1%) said that they brush their teeth three times a day, and most of them (85.2%) depend on rolling methods. 69.2% of them used brushes that are neither hard nor soft, and 28.4% of them use soft brushes and 49.7% of them brush their teeth for about 3 minutes. In terms of brushing time, 27.8% of them brush their teeth after lunch, while 23.8% of them brush their teeth after breakfast. 66.3% of them use fluoric tooth pastes while 19.5 percent of them said, "I have no idea." and 14.2% of them said, "No." In terms of complementary dental hygiene goods, dental goggles are used by 23% of them, and dental threads are used by 78.1% and tooth brushes are used by 78.1% of them, and 42.4% of the subjects use the instruments one to twice a day, and 53.8% of them use them for less than one minute a time. In terms of dental health care, 17.2% of them have a chew of gum and 8.3% of them pay a regular visit to dental clinics and 5.3% of them don't smoke.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.371-378
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• 2002

In this study, 40 hypersensitive teeth of 19 patients were investigated. The procedures performed were as follows: Before desensitization, EPT at occlusal third of buccal surface was done for the evaluation of pulp vitality and the EPT value was recorded for the reference value. And mechanical and thermal test was executed for the test of hypersensitivity. If the tooth responded to the above tests, we did EPT at the exposed surface, using toothpaste as a electrolite medium and recorded the EPT value at patient's response. After the tests had been done, desensitization procedures with Gluma(R) Desensitizer were performed according to the manufacturer's instructions. After desensitization, the same tests except EPT at occlusal third were repeated. All the 40 teeth responded positive before desensitization and negative after desensitization procedures. The EPT value at occlusal third ranged from 31 to 65 (48.9${\pm}$7.2). Before desensitization 34 teeth responded at EPT value of 2 and the remaining 6 teeth was in the range of 17 to 25. After desensitization all 40 teeth responded from 12 to 27 (19.6${\pm}$3.5). The 6 teeth responded at greater number than 2 before desensitization was in the range of 18 to 23. Within the limitations of this study we can conclude that: When a tooth with dentinal hypersensitivity responds to mechanical and thermal stimulation, the tooth shows very low resistance to electricity at the exposed surface while when a tooth is desensitized and doesn't show respond to mechanical and thermal stimuli, the tooth shows increased level of resistance to electric stimulation at the exposed surface. EPT can be used for the diagnosis of dentinal hypersensitivity. Furthermore EPT will be useful to evaluate the outcome of desensitization procedures. However, EPT is not a valid tool for measuring dentinal hypersensitivity.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.262-274
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• 1999

Several alternatives for increasing the fluoride concentration in the mouth, such as water fluoridation, ingestion of fluoride supplements, fluoride paste, fluoride mouthrinse, application of fluoride gel are available. There is an impressive body of evidence that the topically deliverd fluorides are clinically effective in inhibiting the progression of dental caries. Recent studies on the cariostatic action of fluoride have indicated the importance of fluoride in the fluid environment of the teeth. The fluoride levels in unstimulated whole saliva can be considered indicative of F in the aqueous phase available for interaction with the tooth surface at a given time. The retention of F in the mouth after topical fluoride treatment is considered to be an important factor in the clinical efficacy of F. The aim of this study was to determine the elevation and clearance of fluoride in whole saliv after the following topical flouride treatments using HMDS-diffusion technique and fluoride ion electrode. The obtained results were as follow: 1. Average salivary fluoride concentration in the unstimulated whole saliva was $0.0152ppm{\pm}0.0091ppm$. Unstimulated salivary flow rate was between 0.34-0.36ml/min and there was no statistically significant difference among the groups(p>0.05). 2. Except for the immediate time after treatment, fluoride levels followed as APF gel>neutral gel>F-rinse>F-paste. There was no statistical difference between the salivary F concentration of F-paste group and that of control group after 2 hours. In case of F-rinse group, after 3 hours the concentration had dropped to baseline value. But there was statistically significant difference among the F concentraion of F gel groups and that of control group(p<0.05). 3. The mean $AUC_{0-120min}$ values were followed as neutral gel>APF gel>F-rinse>F-paste, and the values of the two former groups were significantly higher than those of the two latter groups(p<0.05).

• Korean journal of communication and information
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• v.35
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• pp.147-178
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• 2006

Screen Quota is very important topic at our whole society not only film industry. Moreover the opinions are sharply divided. So, journalism, at the objective and neutral position, has the responsibility to present objective field to discuss and neutral information. This script censoriously focuses that how Korean Journalism handles Screen Quota issue from the upper mentioned premises. The first point is Korean Journalism gives legitimacy to the Governmental persistence, which is fixing Screen Quota as a hurdle for the FTA settlement so that it should be reduced. Secondly, Korean Journalism has been reducing the importance of the Screen Quota issue as the problem of film industry itself own, describing it as combat between Government and Film Industry. Third, it describes the Screen Quota as a privilege granted to the Film industry only. Finally, it provides power to the point of view of the Government which insists to reduce the Screen Quota mentioning the superiority of the competitiveness of the Koran Films discriminatingly. In conclusion, I could not but define that Korean Journalism is only speaking for America and Korean Government especially about the Screen Quota issue which is divided sharply. What it means is Korean Journalism has not been providing not only objective information but also impartial dispute field to the public for the issue which has very importance socially. The news and discussions about Screen Quota shows that this issue is not free from the progress of FTA which includes the Screen Quota problem. Further on, it could be deduced that the discussion about Korean film industry has kept on focusing its topic to the choice of decreasing or maintaining Screen Quota. The cultural contents have been expanding its importance day by day. Endeavors to settle the enormous problems of film industry should be preceded to strengthen the competitiveness and to prepare against market opening. Consequently, to solve the problems of film industry, Screen Quota should be positioned as a protect policy rather than a remedy for every ill, at the same time all the possibilities should be considered especially for the problems that Screen Quota could not solve.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.360-376
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• 2001

This qualitative research investigated in-service science teachers' perceptions about cooperative learning and their perceived barriers in implementing cooperative learning in their classrooms. The underlying premise for cooperative learning is founded in constructivist epistemology. Cooperative learning (CL) is presented as an alternative frame to the current educational system which emphasizes content memorization and individual student performance through competition. An in-depth interview was conducted with 18 in-service science teachers who enrolled in the first-class teacher certification program during 2001 summer vacation. These secondary school teachers's interview data were analyzed and categorized into three areas: teachers' definition of cooperative learning, issues with implementing cooperative learning in classrooms, and teachers' and students' responses towards cooperative learning. Each of these areas are further subdivided into 10 themes: teachers' perceived meaning of cooperative learning, the importance of talk in learning, when to use cooperative learning, how to end a cooperative class, how to group students for cooperative learning, obstacles to implementing cooperative learning, students' reactions to cooperative learning, teachers' reasons for choosing (not choosing) student-centered approaches to learning/teaching, characteristics of teachers who use cooperative learning methods, and teachers' reasons for resisting cooperative learning. Detailed descriptions of the teachers' responses and discussion on each category are provided. For the development and implementation of CL in more classrooms, there should be changes and supports in the following five areas: (1) teachers have to examine their pedagogical beliefs toward constructivist perspectives, (2) teacher (re)education programs have to provide teachers with cooperative learning opportunities in methods courses, (3) students' understanding of their changed roles (4) supports in light of curriculum materials and instructional resources, (5) supports in terms of facilities and administrators. It's important to remember that cooperative learning is not a panacea for all instructional problems. It's only one way of teaching and learning, useful for specific kinds of teaching goals and especially relevant for classrooms with a wide mix of student academic skills. Suggestions for further research are also provided.

• Journal of dental hygiene science
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• v.3 no.1
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• pp.23-31
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• 2003

In this research, dental health awareness of 3rd graders of high schools in Icheon-city was investigated in order to use the result of this research as the basic data for school dental health program, education direction, and educational purpose. The research was done from Sep. 23. to Oct. 5 and the followings are the results of survey. (1) 85.0% of the students brush their teeth once or twice a day and more female students brush their teeth 3 times a day than male students. (2) 77% of the students had experienced dental caries and 38.0% of the students have periodontal disease, which has lower percentage than cavity. (3) Most of the students can not go to the dentists because they do not have time and 84.0% of the students have been treated in dental clinics so this tells that most of the students had experienced dental treatment. (4) 46.8% of the students had interests in dental health and male students showed more interests than female students and the difference was statistically significant(p<0.05). (5) Most of the students hear the importance and information of dental health from mass media such as TV and radio or from people around. The research shows that most of the students do not get periodic dental checkups. (6) 80.8% of the students had never taught dental health education for improvement of dental health and 76.2% of the students think that the dental health education is needed. There was no difference according to the gender. (7) Most of the students think that the dental health education is needed to prevent cavity and gingiva disease and it shows that more students tend to attend the dental health education. (8) 69.3% of the students think that brushing your teeth is important to maintain good dental health and there was no difference according to the gender. Most of the students weren't aware that periodic dental checkups, right brushing, and using fluoric toothpaste is effective for cavity protection. (9) After looking into the knowledge of the students on dental health, it shows that the knowledge is low and there is no difference according to the gender.

• Journal of dental hygiene science
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• v.5 no.4
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• pp.171-177
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• 2005

This study aims to analyze effects of mothers' socioeconomic features, and knowledge and behavior of oral health on experience and purpose of using dentistry. By survey to 103 mothers of 5-6 year old children, who use day care centers in seoul, the results are obtained as follows: 1. As for the rate of experiencing dental care classified by its purpose, 56.7% for dental treatment, 23.3% for regular check-up and 20.0% for precaution 2. There was no significant difference of correlativity between mothers' socioeconomic features and knowledge of oral health and experience of using dental care, while the lower rate of using dental floss, the higher rate of experiencing dental care(p < 0.01). 3. In respect of correlativity between mother's socioeconomic features and purpose of using dental care, the purpose of regular checkup was high in a group of mothers between 33 and 35 years old(71.4%) by ages and in a group of mothers who graduated from college(57.1%) by academic background(p < 0.05). 4. In correlativity between mothers' behavior of oral health and purpose of using dental care, the result showed that the higher the rate of using dental floss was, the higher the rate of experiencing dental care for a regular check-up was(p < 0.001) and the higher the rate of using fluoride dentifrices was, the higher the rate of using dental care for cure was(p < 0.05). 5. Multiple regression based on dependent variable of experience in using dental care showed that average monthly income(less than 2,500,000 won) was significant explanatory factor with 65% of explanatory variance. On the other hand, multiple regression based on dependent variable of purpose of using dental care showed that vocation(professional job) and age(between 33 and 35 years old) was significant explanatory factor with 70% of explanatory variance for a regular check-up, age(between 33 and 35 years old) and average monthly income (less than 2,500,000 won) was significant factor with 78% of explanatory variance for precaution and age(less than 32 years old) was significant explanatory factor with 33% of explanatory variance for treatment.