• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.306-317
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• 2007

Reproductive cycle with the gonad developmental phases, first sexual maturity, spawning frequency, sex ratio of the dusky mud hopper, Periophthalmus modestus were investigated by histological observations. Monthly variations of the gonadosomatic index (GSI) began to increase in May and reached a maximum in June when the gonad was getting mature during the period of higher ground (water) temperature-long day length. Changes in the GSI showed a negative correlation to the HSI, but coincided with the fatness index. The reproductive cycle can be classified into five successive stages: in female, early growing stage (April to May), late growing stage (April to May), mature stage (May to June), ripe and spent stage (June to August), and recovery and resting stage (August to March); in males, growing stage (April to May), mature stage (May to June), ripe and spent stage (June to August), and recovery and resting stage (August to March); According to the frequency distributions of egg diameters during the breeding season, Periophthalmus modestus is presumed to be a summer breeder, asynchronous group and polycyclic species to spawn 2 times or more during the spawning season. Total eggs and mature eggs in absolute fecundity and relative fecundity (per cm) increased with the increase of body length. Total eggs and mature eggs in absolute fecundity and relative fecundity (per g) did not increase with the increase of body weight. Percentages of first sexual maturity of females and males ranging from 5.1 to 5.5 cm in body length are over 50%, and 100% for fish over 7.1 cm in body length. The sex ratios of females to males over 5.1 cm in body length were not significantly different from a 1 : 1 sex ratio.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.159-177
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• 2002

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle and the angular velocity of the air born phase and understand the control mechanism of the high-bar movement, the somersault, the double somersault, the double somersault with full twist. For this study seven well trained university gymnastic volunteered, Zatsiorky and Seluyanov(1983, 1985)'s sixteen segment system anatomical model was used for this study. For the movement analysis three dimensional cinematographical method(Arial Performance Analysis System : APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 5.1 graphical profromming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and angular velocity were defined. As a result of this study 1. As the rotation of the body increased in the air born phase the projection angle of the CM of the total increased, this resulted the increased of the max hight of the CM. 2. In three dimensional angular velocity the Z axis(vertical direction) projection angular velocity increased as the rotation of the body increased in the airborn phase, but the Y axis and the X axis projection angular velocity did not show significant differences. 3. As the rotation of the body increased in the air born phase the angular movement of the shoulder and the hip showed significant change. These movement act as the starter in the preparation phase. 4. The somersault angle, the twist angle, the tilt angle of the upper body related to the global reference frame in the releas phase the average somersault angle of the three types of high-bar movement was $57.7^{\circ}$, $38.8^{\circ}$, $39.7^{\circ}$, the average tilt angle was $-1.5^{\circ}$, $-5.4^{\circ}$, $-8.4^{\circ}$, the average twist angle was $13.4^{\circ}$, $10.6^{\circ}$, $23.3^{\circ}$. This result showed that the somersault with full twist had the largest movement.

• Korean Journal of Ichthyology
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• v.18 no.4
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• pp.311-318
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• 2006

Ultrastructure of germ cells, the cyst epithelial cells and interstitial cells during spermatogenesis of the stone flounder, Kareius bicoloratus (Pleuronectidae) sampled on the west coast of Korea were investigated by electron microscopic observations. In the primary spermatocyte, the synaptonemal complexes appear in the zygotene stage of the prophase during maturation division. In the growing testis, especially, the interstitial cells (Leydig cells) appear near the primary, secondary spermatocytes and spermatids. Well-developed interstitial cells (steroid hormone secreting cells) which are located in the interlobular space in growing testis have three morphological characteristics of a vesicular nucleus, mitochondria with tubular cristae and smooth endoplasmic reticulum. During spermatogenesis, the primary and secondary spermatocytes attach to the cyst epithelial cell (Sertoli cell) having an elongated ovoid or triangular nucleus and several mitochondria in the cytoplasm. In the growing testis, lipid droplets, the mitochondrial rosettes and glycogen particles appear in the cytoplasm of the cyst epithelial cells near the secondary spermatocytes and spermatids. Particularly, the mitochondria, endoplasmic reticulum, little lipid droplets and the large amount of glycogen particles are present in the cytoplasm of the cyst epithelial cell in the late growing testis. In the late stage of spermiogenesis, the proximal centriole is joined to the nuclear envelope, the distal centriole forms the basal body of the flagellum and gives rise to the axial filament of the flagellum. No acrosome of the sperm is formed as seen in other teleost fish. The head of the spermatozoon is approximately $3{\mu}m$ in length and its tail is about $30{\mu}m$ in length. The axoneme of the tail flagellum of the spermatozoon consists of nine outer doublet microtubules at the periphery and two centrial singlet microtubules at the center. The spermatozoon of this species has two axonemal lateral fins. Especially, the cyst epithelial cells which located near groups of gametes in the various stages, show three functions: nutrition, phagocytosis and steroidogenesis. Especially, the nuclei of cyst epithelial cells in the recovery stage of the testicular developmental stages appear to be irregular in shape after spermiation. Of three functions of the cyst epithelial cell, several characteristics of phagocytosis are showed in the cytoplasm of the cyst epithelial cells in the recovery stage of the testicular developmental stages. At this stage, therefore, it is assumed that the cyst epithelial cells are involved in degeneration and resorption of undischarged germ cells after spermiation.

• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.8-15
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• 1991

This study was carried out in order to examine the urinary excretion of electrolytes (Na, K) and their relationship with blood pressure, and to estimate the amount of daily salt intake in a rural community. From January to March in 1987, a mobile screeing team visited 40 villages, and carried out health screening of 537 adult volunteers whose age were over 30 years and collected 12-hours overnight urine. To determine the completeness of collection, the urinary creatinine was measured. If the creatinine excretion was beyond the range given to the age group, the sample was excluded from the analysis as an incomplete collection : 345 samples were remained for analysis. This study revealed the following results. 1. The mean excretion amounts of urinary electrolytes for 12 hours were Na 193.5 mEq, K 20.8 mEq, creatinine 1.0 g. The mean ratio of electrolytes were Na/K 9.84, Na/creatinine 0.44, K/creatinine 0.046. 2. Both the mean excretion amount of K and the mean ratio of K/creatinine were less in hypertensives than in normotensives. K excretion also showed a tendency towards a decrease in inverse proportion to systolic blood pressure when it exceeded 120 mmHg. There was no significant difference between the hypertensives and normotensives in Na excretion. The sodium to potassium ratio increased in poportion to systolic blood pressure. 3. The mean daily salt excretion amount was 22.4 g. Assuming that 90% of the intake was excreted, the estimated amount of daily salt intake was 24.9 g.

• The korean journal of orthodontics
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• v.34 no.2 s.103
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• pp.177-188
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• 2004

This study is aimed at providing the variables associated with adolescent compliance In orthodontic treatment, and identifies the salient predictors of cooperative behaviors over the course of treatment. Orthodontic attitude scale, orthodontic locus of control scale and demographics data were obtained for 60 adolescent orthodontic patients who had been in treatment a minimum of 10 months. This data was then analyzed in relation to their sex, school age and treatment compliance. The following results were obtained. 1. The scoring of external-powerful others-parents, subscale of the Orthodontic Locus of Control scale, found a statistically significant difference between sex differences (p<0.05). The score of boys was higher than that of girls. 2. The external-powerful others-parents score from the Orthodontic Locus of Control scale showed a significantly positive correlation (p<0.05) with the level of compliance. 3. The salient factors associated with compliance were the adolescent patients' own cognition and decisions. 4. There was a statistically significant correlation between the length of treatment and patient compliance (p<0.05). Thus, there was a substantial decrease in the cooperation of orthodontic patients over time. 5. Other independent variables including age, sex, family environment, religion, academic standing, parents' occupation and education, and brushing frequency were investigated and did not yield any significant relationships. Patient compliance is a critical factor in the efficacy of orthodontic treatment. Individuals vary greatly in their perceptions and attitudes of orthodontic treatment, sociodemographic environments and personality characteristics. In assessing the level of compliance attainable by each individual patient it is advisable To pay sufficient attention not only to the technical matters but also to the psychologic aspects of the treatment progress.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.125-134
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• 2006

We investigated the reproductive cycle of the hard clam, Meretrix petechialis with its gonadal development by histological observations. The seasonal changes in biochemical component of the adductor muscle, visceral mass, foot muscle and mantle of the clam were studied by biochemical analysis, from January to December, 2002. The reproductive cycle of this species can be divided into five successive stages: early stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (July to August) and spent/inactive stage (September to January). Total protein content in the visceral mass was over two times higher than that in the adductor muscle. Monthly changes of total protein content in the adductor muscle were not statistically significant (ANOVA, p = 0.071), while the changes in the visceral mass were significant (p < 0.001). Total protein content in visceral mass was higher during the early active, late active, and ripe stages (from January to May), while the lowest in July. Glycogen content in the adductor muscle was higher than that in the visceral mass. Monthly changes in glycogen contents were statistically significant in both adductor muscle (F = 237.2, p < 0.001) and the visceral mass (F = 64.04, p < 0.001). Glycogen content in the adductor muscle was the highest in the ripe stage (April). Its content was lower in the partially spawned and the spent/inactive stages (June-September). Glycogen contents in the visceral mass were relatively lower until the early active stage, while the highest in the late active stage. RNA content was higher in visceral mass than that in the adductor muscle. Monthly changes in RNA contents were significant in both adductor muscle (F = 195.2, p < 0.001) and visceral mass (F = 78.85, p < 0.001). RNA content in the adductor muscle was high in the early active stage (January-February), and then it decreased rapidly in the late active stage (March-April), thereafter, slightly increased during the partially spawned stage (June-July). RNA content in the visceral mass reached a maximum during the ripe stage (May), and then it decreased rapidly during the partially-spawned stage (June-July). There was significant positive correlation in total protein contents between adductor muscle and visceral mass (r = 0.715, p = 0.020). However, there was no correlation between adductor muscle and visceral mass in glycogen (p = 0.550), while a negative correlation was found between the adductor muscle and visceral mass in RNA (p = 0.518) contents. Especially, changes in RNA content showed a negative correlation between the adductor muscle tissue and visceral mass. Therefore, these results suggest that the nutrient content of the adductor muscle, visceral muscle and foot muscle changed in response to gonadal energy needs.

• Clinical and Experimental Pediatrics
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• v.49 no.9
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• pp.952-958
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• 2006

Purpose : The survival rate of infants weighing less than 1,000 g at birth(extremely low birth weight infants, ELBWI) has increased due to recent advances in perinatal and neonatal intensive care. The purpose of this study was to evaluate the survival rates of ELBWI born at Seoul National University Hospital during the last six years. Methods : A total of 99 infants were divided into three groups(period I: 2000 to 2001, period II: 2002 to 2003, period III : 2004 to 2005) based on date of birth. We compared the survival rate of ELBWI over the three periods, using CRIB II score for adjustment for clinical severity. Results : Overall survival rate of ELBWI was 74.7 percent. The survival rate of ELBWI increased over the three periods(period I: 60.7 percent, period II : 73.3 percent, period III : 85.3 percent). The threshold of viability(defined as survival of at least 50 percent of infants) was 25 weeks of gestation and 600 g at birth. The birth weight-specific survival rates increased considerably over the three periods for infants <750 g at birth(period I: 10 percent, period II: 46.2 percent, period III : 70.6 percent). The survival rates of ELBWI over the three periods increased much remarkably after adjustment for clinical severity by CRIB II score. Conclusion : In our institution, survival rates of ELBWI during the last six years continued to improve, particularly for infants weighing <750 g at birth. This increase in survival rates was not associated with the clinical severity of ELBWI.

• Clinical and Experimental Pediatrics
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• v.52 no.3
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• pp.303-309
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• 2009

Purpose : To identify the short-term clinical outcomes of late preterm infants and to test the hypothesis that late preterm infants have more clinical problems during the early postnatal period than term infants. Methods : One hundred late preterm infants [gestational age (GA) $34^{+0}$-$36^{+6}$ weeks] and the same number of term infants (GA $37^{+0}$-$41^{+6}$ weeks) were randomly selected from 289 late preterm infants and 825 term infants born in the Seoul National University Bundang Hospital between January 2007 and December 2007, and their electronic medical records were reviewed and analyzed. Results : Compared to term infants, late preterm infants had significantly more medical problems such as temperature instability (odds ratio [OR] 8.7), hypoglycemia (OR 17.5), intravenous fluid infusion (OR 10.2), evaluation for sepsis (OR 9.4), respiratory problems (OR 7.5), apnea and bradycardia (OR 8.6), phototherapy for jaundice (OR 3.6), and feeding intolerance (OR 10.0). Hospital stay was also significantly longer in late preterm infants. Conclusion : Late preterm infants had significantly more medical problems and increased length of hospital stay compared to term infants. More attention should be given to caring for these late preterm infants in newborn nursery during the early postnatal period.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.81-86
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• 2012

The present study was evaluated the antibacterial effect of the combination of $Coptidis$ $rhizoma$, $Glycyrrhiza$ $uralensis$ Fischet, $Schizandra$ $chinensis$ and $Corni$ $Fructus$(1:1:1) extracts(CGSC10). Furthermore, the effectiveness of CGSC10, sodium chlorate, and the combination of CGSC10 and sodium chlorate(CGSCS10) against $E.$ $coli$ O157:H7 infection was studied using ICR female mice. During the incubation period, the dose of 5, 10, and 20% CGSC10 was inhibited the growth of $E.$ $coli$ O157:H7 by 34.7, 60.2, and 76.4%, respectively. For 7 days after single challenge with $E.$ $coli$ O157:H7, forty female ICR mice were divided into four experimental groups which were administered in drinking water with saline, 10% CGSC10, 15 mM sodium chlorate, and CGSCS10, respectively. On the 3rd day, the number of $E.$ $coli$ O157:H7 in mouse feces was significantly decreased by administration of CGSC10, 15 mM sodium chlorate, and CGSCS10 ($p$ < 0.001). On the 7th day-after administration, CGSC10, sodium chlorate, and CGSCS10 were decreased the number of $E.$ $coli$ O157:H7 by 27.1, 67.7, and 83.3%, respectively. According to the results of the present study, administration of CGSCS10 to mice can reduce the severity of $E.$ $coli$ O157:H7 infection. In addition, it is suggested that CGSCS10 represents a good candidate for the treatment of enteric infections in domestic animals.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.45-54
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• 2012

We investigated environmental characteristics of the tidal flat oyster aquafarms to clarifyeffects of the tidal flat environmental factors on growth and mortality of the tidal flat oyster Crassostrea gigas by the Net Bag Rack Culture System in two districts in Western Korea. In this study, we have carried out the basic environmental investigation on growth of the single tidal flat, water quality and sediments, etc. in Taean and Seosan districts, Choongcheongnam-do, where the single tidal flat oyster aquaculture have been performed by the net bag rack culture system. In June 2011 when the final survey carried out at the two districts in western Korea, the mortality in Seosan district was higher than that in Tae-an district. Judging from the results of growth and mortality of the single tidal flat oysters investigated at two sites of Jinsan-ri in Taean and Chang-ri in Seosan districts, two results of Taean district showed higher growth and lower mortality than those of Seosan district. It is assumed that the proper acceptable density possible for growth of the tidal flat seeds and the secure of economics, in case of plastic cultivate net with the size of $50{\times}80cm$, are about 200 individuals. In this study, It was clarified that selection of the suitable sites, the input into the net bag of high quality oyster seeds and selective dispersion in the optimal density of the single tidal flat oyster have an effect on growth and mortality of the tidal flat oyster.