• Journal of Oral Medicine and Pain
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• v.13 no.1
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• pp.53-60
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• 1988

The authors have studied the growth and development of mandibular permanent teeth in order to the make basic data that are necessary to determine the forensic age. The 631 subjects whose ages range from 3 years to 18 years were selected to analyze calcification degree of mandibular teeth. The results were as follows: 1. There were significant differences between adjacent ages, except 14-15 years and 17-18 years. 2. In each tooth, these were differences between adjacent ages from 3 years to 10 years, except central incisor and third molars. 3. All teeth were almost completely developed at the age of about 14 years, except second and third molars. 4. In each tooth, there were the widest significances between adjacent ages in premolars.

• Journal of the Korea Safety Management & Science
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• v.25 no.1
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• pp.67-74
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• 2023

This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

• Journal of Nutrition and Health
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• v.34 no.5
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• pp.568-579
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• 2001

This study was conducted to identify the characteristics of Korean diet in the view of food and food group intakes. The study subjects consisted of preschool children(PC), elementary school children(EC), high school students(HS), college students(CS), and adults over 30 years old living Seoul and the surrounding areas. The subjects over 30 years old were classified to 30-49 years, 50-69 years, and over 70 years. A dietary survey was conducted using 24-hour recall method and data were collected from 2392 subjects. Rice was a major contributor to many nutrients intake because of the amount of consumption. Vegetable oil made great contribution to fat intakes and eggs, squid, and anchovy supplied much cholesterol compared to other foods in all the age groups. Milk was major contributor of fat and cholesterol as well as calcium in younger age group, and seasoning gave much contribution to iron intakes. Mean dietary variety score(DVS) was 32 for EC group and 17 for subjects over 70 years, and tended to decrease along the increasing age. EC group consumed most variable number of foods of all groups but they consumed many junk foods, therefore the MAR value was low despite their high DVS value. Mean dietary diversity score(DDS) of each age group from PC group to subjects over 70 years was 4.34, 4.28, 3.79, 3.89, 3.76, 3.56, and 3.25, respectively. Food group, which was consumed below the minimum amount, was mainly fruits in all the age groups, and many subjects in HS group and over 30 years consumed dairy products below the minimum amount. From these results, age specific nutritional problems were found. PC group and subjects over 50 years seemed to need more diverse food intake than now, EC group did nutrient dense food, and HS group and subjects over 30 years did dairy products. Also, subjects took various nutrients from rice and seasoning contributed to some nutrients intakes. (Korean J Nutrition 34(5) : 568∼579, 2001)

• Journal of Preventive Medicine and Public Health
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• v.9 no.1
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• pp.153-158
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• 1976

It is clearly defined through a number of authoritative studies that the age of menarche influenced by the various combined factocs such as nutrition status, physical status, physical growth and development status, socio-economic status, locality, culture, education level, climate, race heredity etc. In order to obtain statistical data regarding the menarche of Korean school girls, anthers investigated on 4207 middle school girls and 703 woman college students in Seoul and Teagu during the period of September 10 to 30, 1973 and the result are summarized as followings; 1. The rates of menses experience by years were 18.2% in the age group of 12 years girls, 31.9% in 13 years, 64.6% in 14 years, 89.8% in 15 years, 98.1% in 16 years respectvely. 2. The average age of menarche for the 2504 school girls who were born during the yrar of 1957-1961 is 13.4 years with the rang of 9 years to 16 years. And the most frequent age of menarche is 13 years. 3. The average age of menarche for the 703 woman college students who were born during the year of 1950-1954 is 14.3 years with the rang of 9 years to 18 years. And the most frequent age if menarche is 13 years. 4. The appearence of menarche is most common in August (20.7%) for the group who were born during the year of 1957-1961 and most rear in November (4.2%). And it is also most common in August (19.9%) for the group who were born puring the year of 1950-1954 but most rear in June (3.4%).

• Korean Journal of Community Nutrition
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• v.29 no.3
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• pp.222-233
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• 2024

Objectives: This study was conducted to investigate the status of total sugar intake and contributing foods in Korea according to age groups. Methods: This study used 24-hour dietary recall data from the 8th Korea National Health and Nutrition Examination Survey (2019-2021) to investigate the nutritional and total sugar intake status among Koreans. A total of 18,338 research participants (≥3 years old) were included in this study. To analyze the types of foods contributing to total sugar intake, these foods were categorized into 15 types. Moreover, we examined the total sugar intake and ranked the most consumed foods by age groups (3-11 years, 12-18 years, 19-34 years, 35-49 years, 50-64 years, over 65 years). A survey procedure was employed for statistical analysis. Results: The energy intake ratio from total sugars was approximately 12%-15%, which was within the recommended range. However, the proportion of individuals consuming total sugar exceeding 20% of their total caloric intake is nearly 20%, raising concerns about excessive sugar consumption. Furthermore, the percentage of participants whose intake of sugar from processed foods exceeded 10% of their total calories was highest in the 12-18 age group at 37.1%, followed by the 3-11 age group at 35.2%, and the 19-34 age group at 34.0%. Carbonated drinks, cola, and cider were the primary foods consumed by children and adolescents (3-18 years old) and young adults (19-34 years old). For middle-aged and older adults, mixed coffee with sugar and cream was a prominent contributor to sugar intake. Conclusions: This study investigated sugar consumption patterns among Koreans, finding the principal foods contributing to this intake. Identifying these contributors is pivotal, given their potential impact on public health.

• Journal of Korean society of Dental Hygiene
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• v.11 no.1
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• pp.59-68
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• 2011

Objectives : To investigate the knowledge and recognition level of fluorine by teaching career among class teachers, who are primarily responsible for oral health education, despite lack of expertise in oral health, by playing a model role for students through continuous contacts with them, and provide basic elementary data about accurate knowledge and how to correctly use fluorine remarkably effective in preventing dental caries. Methods : A self-administered survey was conducted with 539 teachers at 21 elementary schools in Jinhae City from September 1 to October 15, 2010, drawing the following conclusions. Results : 1. As for the channel for acquiring knowledge of oral health, the highest frequency was found in health programs for respondents with less than 9 years of career, in dental clinics for those with 20 to 29 years of career, and in PR booklets for those with 10 to 19 years and 30 years and longer of career. 2. Use of fluorine-containing toothpaste and fluorine spread is very effective and effective in preventing dental caries got 64.9%, 72.2%, 72.3%, 77.7% and 54.0%, 63.1%, 62.2%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 3. Intake of fluoride and toothbrushing with fluoric solution is very effective and effective in preventing dental caries got 33.3%, 40.1%, 39.5%, 55.3% and 50.0%, 54.9%, 48.8%, 69.7%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 4. Use of fluoric tablets is very effective and effective in preventing dental caries got 32.9%, 36.0%, 36.1%, 47.3%, respectively, among elementary school teachers with less than 9 years, 10 to 19 years, 20 to 29 years, and 30 years and longer of career. 5. Most of the elementary school teachers knew the fact that fluorine increases dental resistance to cavity and prevents bacterial growth but gave incorrect responses to properties of becoming basic nutrients or inducing recalcification. Conclusions : Various types of application of fluorine during the elementary-level childhood experiencing the most frequent dental caries will be very useful in improving oral health in the future. It is necessary to enable class teachers to get correct recognition of fluorine through supplementary and job training based on technical knowledge and various educational materials so that they, who are directly responsible for health management through continuous contacts with students, can understand how to correctly use fluorine and get accurate knowledge.

• Korean Journal of Audiology
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• v.25 no.3
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• pp.119-123
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• 2021

Background and Objectives: The influence of music training on different areas of the brain has been extensively researched, but the underlying neurobehavioral mechanisms remain unknown. In the present study, the effects of training for more than three years in Carnatic music (an Indian form of music) on the discrimination ability of different areas of the brain were tested using P300 analysis at three electrode placement sites. Subjects and Methods: A total of 27 individuals, including 13 singers aged 16-30 years (mean±standard deviation, 23±3.2 years) and 14 non-singers aged 16-30 years (mean age, 24±2.9 years), participated in this study. The singers had 3-5 years of formal training experience in Carnatic music. Cortical activities in areas corresponding to attention, discrimination, and memory were tested using P300 analysis, and the tests were performed using the Intelligent Hearing System. Results: The mean P300 amplitude of the singers at the Fz electrode placement site (5.64±1.81) was significantly higher than that of the non-singers (3.85±1.60; t(25)=3.3, p<0.05). The amplitude at the Cz electrode placement site in singers (5.90±2.18) was significantly higher than that in non-singers (3.46±1.40; t(25)=3.3, p<0.05). The amplitude at the Pz electrode placement site in singers (4.94±1.89) was significantly higher than that in non-singers (3.57±1.50; t(25)=3.3, p<0.05). Among singers, the mean P300 amplitude was significantly higher in the Cz site than the other placement sites, and among non-singers, the mean P300 amplitude was significantly higher in the Fz site than the other placement sites, i.e., music training facilitated enhancement of the P300 amplitude at the Cz site. Conclusions: The findings of this study suggest that more than three years of training in Carnatic singing can enhance neural coding to discriminate subtle differences, leading to enhanced discrimination abilities of the brain, mainly in the generation site corresponding to Cz electrode placement.

• Journal of Audiology & Otology
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• v.25 no.3
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• pp.119-123
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• 2021

Background and Objectives: The influence of music training on different areas of the brain has been extensively researched, but the underlying neurobehavioral mechanisms remain unknown. In the present study, the effects of training for more than three years in Carnatic music (an Indian form of music) on the discrimination ability of different areas of the brain were tested using P300 analysis at three electrode placement sites. Subjects and Methods: A total of 27 individuals, including 13 singers aged 16-30 years (mean±standard deviation, 23±3.2 years) and 14 non-singers aged 16-30 years (mean age, 24±2.9 years), participated in this study. The singers had 3-5 years of formal training experience in Carnatic music. Cortical activities in areas corresponding to attention, discrimination, and memory were tested using P300 analysis, and the tests were performed using the Intelligent Hearing System. Results: The mean P300 amplitude of the singers at the Fz electrode placement site (5.64±1.81) was significantly higher than that of the non-singers (3.85±1.60; t(25)=3.3, p<0.05). The amplitude at the Cz electrode placement site in singers (5.90±2.18) was significantly higher than that in non-singers (3.46±1.40; t(25)=3.3, p<0.05). The amplitude at the Pz electrode placement site in singers (4.94±1.89) was significantly higher than that in non-singers (3.57±1.50; t(25)=3.3, p<0.05). Among singers, the mean P300 amplitude was significantly higher in the Cz site than the other placement sites, and among non-singers, the mean P300 amplitude was significantly higher in the Fz site than the other placement sites, i.e., music training facilitated enhancement of the P300 amplitude at the Cz site. Conclusions: The findings of this study suggest that more than three years of training in Carnatic singing can enhance neural coding to discriminate subtle differences, leading to enhanced discrimination abilities of the brain, mainly in the generation site corresponding to Cz electrode placement.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.134-138
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• 2006

The result that test 3 years since 2002 allowing 6 processing such as $40{\times}5\;cm$ to supply basis data of method of cultivation establishment investigating productivity of Saururus chinensis by the number of cultivation years and planting distance, is as following. Plant height of foliar growth was good 1 year eats little, but 2 years planting distance $40{\times}10\;cm$, 3 years was best in $40{\times}20\;cm$ and there were many the number of tillerings 1, 2, all 3 years do high plant density, and rhizoma growth is 1, 2 years does high plant density, it was good tendency, but 3 years is best in $40{\times}20\;cm$. 1 year is most in planting distance $40{\times}5\;cm$, 2 years $40{\times}10\;cm$, 3 years $40{\times}20\;cm$, $1{\sim}2$ year accumulation quantity $40{\times}10\;cm$, $1{\sim}3$ year accumulation quantity $40{\times}10$, 20 cm in goods foliar amount.

• Journal of the korean academy of Pediatric Dentistry
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• v.5 no.1
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• pp.12-18
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• 1978

The author has observed the ectopic eruption pattern on oblique cephalogram of 195 children. (5years: 78, 6 years: 58, 7 years: 59). The results were as follows; 1) Making a comparison between hold type and jump type of ectopic eruption, there are 4 cases in Hold type, 5 cases in jump type. 2) Making a comparison of ectopic eruptin between male and female, there are 7 cases in male, 2 cases in female. 3) Making a comparison of ectopic eruption between right side and left side, there are 5 cases at right side, 4 cases at left side. 4) Making a comparison of ectopic eruption among 5 years to 7 years, there are 4 cases in 5 years, 3 cases in 6 years, 2 cases in 7 years. 5) The prevalence of ectopic eruption of the maxillary first molar was 4.61%. 6) Normal eruption angle of the maxillary first molar is prevailing in $80^{\circ}{\sim}85^{\circ}$.