• Parasites, Hosts and Diseases
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• v.27 no.1
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• pp.47-56
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• 1989

Some biological characteristics of Centrecestus armatui were studied using albino rats as its experimental host. The metacercariae were collected from Zacco Platypus by artificial digestion method. Laboratory rats(Wistar) were fed each 100 or 200 metacercariae and sacrificed on 1, 2, 3, 4, 5, 6, 8, 14 and 28 days after infection to recover worms of various ages. The average recovery rate was 10.7% from 82 rats. The rate decreased rather slowly for the first 8 days but showed a steep decrease thereafter. Of the worms, 35.5% were recovered from the duodenum and 62.5% from the jejunum. At metacercarial stage, body length was $293{\mu\textrm{m}}$ and body width $144{\mu\textrm{m}}$. At adult stage, the length and width reached $382{\mu\textrm{m}}$ and $214{\mu\textrm{m}}$ respectively at 14 days after infection. The testes and Mehlis' gland were recognized at metacercarial stage, whereas the ovarian anlage appeared on the 1st day of infection, seminal vesicle and vitellaria on the 2nd day, and seminal receptacle and uterine eggs on the 3rd day. Until 8 days after infection the genital organs developed continuously and the number of uterine eggs increased. The above results show that albino rats are one of useful experimental hosts for C. armatus and the worms can develop to adults in 3 days after infection.

• Journal of Sericultural and Entomological Science
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• v.27 no.1
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• pp.1-11
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• 1985

In order to clarify the taxanomic position of a new microsporidia K79 which was isolated from the silkworm larvae, Bombyx mori L. in Korea in 1979, the following several experiments such as estimation of pathogenicity in different instar, histopathological examination under light and electronic microscope and examination of fine structure of the sporse were carried out and their result obtained are as follows. In the test of pathogenicity by oral inoculation, the new microsporidia K79 was lower than Nosema bombycis and the susceptibility of the new microsporidia to silkworm was getting lower as the silkworm larvae grew. The lesion of Silkworms' tissue which was infected with the new microsporidia K79 was found in the epithelial cells of trachea, fat body and silk gland cells. The developmental process of the new microsporidia K79 in vivo could be divided into the following five stages: sporoplasm, schizont, sporont, sporoblast, and spore. The process was just the same as the of N. bombycis, but its development was slower than that of N. bombycis. Several differences in the fine structure of the spore under electron microscope, which could be important keys for the classification of microsporidia, were obtained. Anchoring disk and polaroplast lamella of the new microsporidian spore were disclosed to be different from those of N. bombycis. An average number of polar filament coils of the new microporidian spore was 16 at an angle of 75$^{\circ}$. On the basis of various keys for the classification of microsporidia, the results obtained from various experiments proved that the newly isolated microsporidia should be classified into the Genus, "Nosema", nut is further classification for species should be conducted in the future. Therefore, it may be reasonable that the new microsporidia is temperally classified as Nosema sp. K79 considering the fact that it was discovered in Korea in 1979.a in 1979.

• Korean journal of applied entomology
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• v.42 no.1
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• pp.53-56
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• 2003

Development and reproduction of the rice armyworm, Pseudaletia separata Walker, were investigated under different temperatures (13, 15, 18, 20, 25, 30, and 33$^{\circ}C$ ). It took 80.6 days to grow from egg to pre-adult at 15$^{\circ}C$, and 27.3 days at 30$^{\circ}C$ (3.0 times shorter growth period compared with that at 30$^{\circ}C$ ). The range of developmental temperature of rice armywom was 15-30$^{\circ}C$. Survival rate from hatched larva to pre-adult was the highest as 70.6% at 25$^{\circ}C$. Pre-oviposition period and the adult longevity were 4.2 and 12.3 days at 15$^{\circ}C$, and 2.9 and 8.0 days at 30$^{\circ}C$, respectively. The highest average fecundity per female was 816.6 at 25$^{\circ}C$. The net reproductive rate (R$\_$o/) and intrinsic rate of natural increase (r$\_$m/) were the highest at 25$^{\circ}C$ as 913.0 and 0.175, respectively. As a result, it was considered that optimum of temperature for P. separata growth was = 25.0$^{\circ}C$.

• Parasites, Hosts and Diseases
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• v.22 no.2
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• pp.181-189
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• 1984

The metacercariae of Echinostoma cineterchis (Trematoda: Echinostomatidae) were found infected in the loaches (Misgurnus anguillicaudatus) purchased from two local markets in Korea. Identification of the metacercariae was done after obtaining adult worms from experimentally infected albino rats. Brief course of worm development in rats was also observed up to 28th post-infection day. The results are as follows: 1. The metacercariae of E. cinetorchis were detected from 5 (10.9%) out of 46 loaches examined and the average metacercarial burden per infected loach was 34.4. They were always found from the posterior abdominal wall. 2. The worm recovery rate from 8 rats was 24.6% in average. It was observed that the rate decreased according to age of infection; from 40.7% after 6 days to 15.0% after 28 days. 3. The adult worms were morphologically characterized by the presence of head crown with derfally uninterrupted collar spines, 37-38 in number, and the tendency of migration or disappearance of testes. So that they were identified as Echinostoma cinetorchis Ando et Ozaki, 1923. 4. The development of worm was very rapid during 6-10 days after infection and became much slower thereafter. During the rapid worm growth the development of genital organs was more prominent than that of non-genital organs. From the results it is concluded that the loach is involved in the life cycle of E. cinetorchis in this country and may take a role for infection source to animals and man. It is also confirmed that migration or loss of testes is the distinct specific character of this echinostomatid fluke.

• The korean journal of orthodontics
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• v.39 no.1
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• pp.28-35
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• 2009

Objective: The purpose of this study was to investigate the relationship between menarche and cervical vertebral maturation. Methods: Lateral cephalograms of 67 young korean girls within the range of 1 year before or after their menarche were gathered. The concavity of the cervical vertebrae base and the ratio of the base length to the 3rd and 4th cervical vertebrae anterior height were measured and analyzed. Results: The mean measured values were as follows, concavity of the 3rd cervical vertebrae base: 1.27(${\pm}0.18$) mm, concavity of the 4th cervical vertebrae base: 1.06(${\pm}0.15$) mm, ratio of the base length to the 3rd cervical vertebrae anterior height: 0.73(${\pm}0.06$) and ratio of the base length to the 4th cervical vertebrae anterior height: 0.70(${\pm}0.05$). There was a significant increase in the ratio of the base length to the 3rd vertebrae anterior height and the base concavity of the 3rd and 4th cervical vertebrae during the period of 1 year before to 1 year after their menarche. Conclusions: These characteristics of the 3rd and 4th cervical vertebrae on the lateral cephalogram can provide useful clues on evaluating the growth stage.

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.1-25
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• 2008

Purpose : Since 1967, The Korean Pediatric Society and Korean Government have developed Korean Growth Standards every 10 years. Last version was published in 1998. During past 40 years, Korean Growth Standards were mainly descriptive charts without any systematic nor statistical standardization. With the global epidemic of obesity, many authorities such as World Health Organization (WHO) and United States' Centers for Disease Control (CDC) have been changed their principles of growth charts to cope with the situations like ours. This article summarizes and reviews the whole developmental process of new 2007 Korean Growth Charts with discussion. Methods : With the initiative of Division of Chronic Disease Surveillance in Korea Centers for Disease Control and Prevention, we have performed new national survey for the development of new Standards in 2005 and identified marked increase of childhood obesity and plateau of secular increment of final height in late adolescents. We have developed new Growth Standards via adapting several innovative methods, including standardization of all available raw data, which were acquired in 1997 and 2005 national survey and full application of LMS method. Results : We could get new standardized charts; weight-for-age, length/height-for-age, weight-for-height, head circumference-for-age and BMI-for-age. Other non-standardized charts based on 2005 survey data were also published; waist circumference-for-age, mid-arm circumference-for-age, chest circumference-for-age and skinfold-for-age. Clinical guideline was also developed. Conclusion : Developmental process and results of new Korean Growth Charts are comparable with other internationally well-known Growth Standards, WHO 2006 Growth Standards and CDC Growth Charts. 2007 Korean Growth Charts are relevant especially in Korea and Korean ethnic groups.

• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.601-611
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• 1996

Craniofacial growth pattern is an important diagnostic data in the course of orthodontic diagnosis and treatment planning ; it also has great influence in the establishment of occlusion as well as shaping and development of face. There have been many studies to classify different craniofacial growth patterns and attempts to predict growth patterns. This study aimed to correlate craniofacial growth pattern and symphysis morphology. 120 adult patients with age from 19 to 39 (mean age : 23.1) were chosen as subjects , using lateral cephalometric films. their anterior to posterior facial height ratios were calculated. They were divided into 3 groups - clockwise growth pattern with $56\%-62\%$(36subjects), counter-clockwise growth pattern group with $65\%$-80\%$(43subjects) and normal growth pattern group with $62\%-65\%$(41subjects). Symphysis morphology and Prominence evaluation in each subject were studied and the following conclusions were drawn : 1. In comparison of symphysis morphology between the sex groups, men showed large symphysis height and prominence. 2. Concerning the symphysis morphology, the clockwise growth pattern group showed larger height, H/D ratio and actual length but smaller depth, angle, effective length and E/A ratio compared to the counter -clockwise growth pattern group. 3. Those with smaller prominance of symphysis showed clockwise growth tendency and those with larger prominance showed counter-clockwise growth tendency.

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.551-556
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• 2004

The purpose of this study was to suggest a systematic and scientific method for measurement of children's growth development, in which the accuracy of existing diagnosis method has not been concretely examined yet. The most popular method for diagnosis of children's growth is to analyze the opening degree of growth plate in each joint by X-ray image. However, X-ray method has some disadvantages; it is impossible to measure the diagnosis of growth periodically and repeatedly due to the radiation problem. Hence, this study introduced a profile analysis and the algorithm of analyzing the image of growth plate with the BUA(Broadband Ultrasound Attenuation) of calcaneus, to verify the possibility of alternative ultrasonic method harmless to human body. We obtained the images of growth plate in proximal tibiae, phalanges, and calcanei of 269 children (7∼16 years old) with X-ray. And the image of growth plate in calcanei was also obtained front those children with ultrasound. The results showed that the time of the opening degree of growth plate in each joint was almost consistent between X-ray and ultrasonic images. Also, the images of growth plate measured by X-ray and ultrasound showed the high correlation. Therefore, it is expected that the algorithm of ultrasonic profile analysis introduced in this study can replace the existing X-ray method to measure the growth plate correctly.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.19-31
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• 2000

Developmental changes of dental arch width and length from 6.6 to 13.6 yews of age have been studied in twenty boys and thirteen girls in Korean school children. A series of 8 dental casts obtained from each child was measured in the intercanine width, intermolar width and arch length. Afterwards, mean value and each standard deviation of each age group and each gender were obtained, and corresponding graphs were drawn. The finding of this study can be summarized as follows : 1. Maxillary intercanine widths increased until age of 13.5 in males and age of 12.5 in females. On the other hand, mandibular intercanine widths increased until age of 11.5 in males and age of 9.6 in females and after there were no changes. 2. Maxillary intermolar widths increased until age of 13.5, but annual increments reduce from age of 12.5 in both sex. Mandibular intermolar widths increased until age of 13.5 in males and age of 12.5 in females. Annual increments of maxillary intermolar width greater than those of mandibular intercanine width in both sex. 3. Maxillary dental arch lengths increased until age of 10.6 in both sex, and after decreased until age of 13.6. Mandibular dental arch lengths increased until age of 10.5 in males and age of 9.6 in females, and after decreased until a9e of 13.6. 4. Developmental changes of dental arch width and length showed individual variation.

• Parasites, Hosts and Diseases
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• v.28 no.1
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• pp.53-62
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• 1990

The growth and developmental pattern of H. continua was observed after experimental infection of their metacercariae to chicks. The recovery rate of worms from the chicks at 1 to 28 days post-infection(PI) was 12.8% in average. The rate remained fairly high for early 4 days of infection but decreased thereafter rapidly till 28 days PI. Most of the nukes, 91.9%, were recovered from the ileum of the chicks. In metacercariae, genital organs such as the ovary, testes, seminal vesicle, seminal receptacle and genital sucker were recognizable. At one day PI Mehlis'gland appeared, and at 2 days follicular vitellaria were observed. At 3 days PI, eggs were formed in the uterine tubule and increased in number as the worm grew old. The worms reached $2,990{\;}{\mu\textrm{m}}$ in length and $525{\;}{\mu\textrm{m}}$ in width at 28 days PI. Genital organs developed rapidly in early stages of infection but slowly thereafter to 28 days Pl, whereas non-genital organs developed steadily through the infection period. It was proved by this experiment that chicks should be a moderately suitable final host of H. continua.