• Ocean and Polar Research
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• v.26 no.3
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• pp.425-431
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• 2004

The study focuses on the morphology of larval and juvenile codlets, Bregmaceros atlanticus, collected from the East China Sea in May 2001 and September 2002. A total of 47 individuals were collected by using an IKMT, and the range of their body lengths was $2.41{\sim}17.18$ mm. Specimens can be categorized into two groups: larvae and juvenile. The first group, in which the yolk is completely absorbed, had a body length of 2.41m. They had big heads, and large and thick melanophores were sparsely scattered about the head, bottom of the pectoral fins, rear parts of the trunk and ends of the notochords. The specimens had a body length of 2.54mm and over, and thin and elongated body trunks. Their heads were significantly smaller, including the body depth, and melanophores were coarsely developed all over their bodies. Occipital rays, the first and unique-ray dorsal fin, were observed on individuals of body length greater than 4.01 m, and the rays grew proportionally with body length, but didn't reach the root of the second dorsal fin. The second group, juveniles, had an body length of 9.82mm and over, and their fin rays satisfied the completed numbers of rays and vertebrae for adults. Melanophores were densely scattered all over the body, where thick colors were observed on the rear parts of the dorsal and anal fins and front part of the caudal fin.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.1-10
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• 1998

The early history of Korean mandarin fish, Siniperca scherzeri was studied to obtain some information required in aquaculture and reinforcement of natural population. During the period from June 1996 to July 1997, the mature adults of Siniperca scherzeri were collected from the middle Soyang Lake at Puksan - myon, Chunchon - shi, Kangwon - do, Korea. The eggs from females were obtained by injecting HCG or/and GnRH - a and fertilized by dry method in the laboratory. The fertilized eggs, measuring 1.70~2.10 mm in diameter and expanded to 2.20~2.66mm after absorption of water, were globosity, light orange yellow, separative, submergence and had one large oil globules of 0.5~0.7 mm. The blastodisc was formed in 1 hour and cleavage started in 1 hour 30 min. after fertilization, and the intervals of each stage of cleavage was about 50 min. at the water temperature of $21{\sim}24^{\circ}C$. Hatching occurred 131 hours 30 min. after fertilization and newly hatched larvae were 5.86~6.85 mm in total length(TL) and numerous stellate melanophores were distributed on the yolk and abdomen of caudal peduncle. The yolk was almost absorbed and the teeth development. 3 days after hatching, at 6.98~7.60 mm TL. The head spines and the teeth were largely developed and all fins were completely formed and became postlarva stage 15 days after hatching, at 10.10~12.90 mm TL. The body shape and the color pattern were similar to adult, 25 days after hatching, at 15.3~23.8 mm TL. In 5 months after hatching were reached at 154.10~175.02 mm TL and 49.32~82.67 g in body weight.

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.269-277
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• 2011

Age and growth pattern of Pacific cod Gadus macrocephalus were determined using samples collected in Jinhae Bay in Korea during the spawning period from 2006 to 2009. The ages of 333 specimens were estimated using their otoliths. The reliability of scales as a means of age determination was analyzed by comparing the ages estimated from otoliths and scales of 96 specimens. The scales collected from the base of the second dorsal fin or from the caudal peduncle were proved to be suitable for age determination of Pacific cod. Monthly changes in the marginal index in otoliths decreased from December showing the lowest value in February. Ages ranged from 4 to 6 years for both females and males, and most of them were 6 years old. Relationships between the otolith radius (R) and total length (TL) were TL=10.4R+3.1 for males, and TL=11.5R+3.4 for females. The growth curves in total length ($L_t$, cm) were expressed as $L_t$=141.5 [1-exp{-0.089 (t+0.209)}] for males and $L_t$=127.5 [1-exp {-0.124 (t+0.077)}] for females.

• Korean Journal of Ichthyology
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• v.29 no.1
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• pp.1-12
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• 2017

A natural hybrid of interspecific between the Coreoleuciscus splendidus and C. aeruginos (Cypriniformes: Cyprinidae) was captured in the Hwang-ji Stream, a tributary of the Nakdong River basin in Korea. An interspecific hybrid between C. splendidus and C. aeruginos was genetically identified based on morphological characteristics and the sequence analysis of nuclear recombination activating gene 1 (RAG1) gene (1,334 bp) and mitochondrial cytochrome c oxidase subunit 1 (CO1) gene (1,551 bp). As a result of morphological variations, the natural hybrid appeared to have an intermediate character between two parental species (C. splendidus and C. aeruginos) in three variations of black array (s) on dorsal, caudal and anal fin rays. Phylogenetic analysis inferred from RAG1 and CO1 sequence data revealed that Coreoleuciscus populations from Hwang-ji stream consist of two pure Coreoleuciscus species and a hybrid individual group. The individuals were clearly identified the cross and reciprocal hybrid by CO1 gene analysis. In RAG1 gene, 13 nucleotide variation loci were detected and the hybrid individuals displayed the double peaks of sequence chromatograms at the 9 diagnostic positions. In this study, molecular data and morphological variations were clearly demonstrated that hybridization did occur between C. splendidus and C. aeruginos. However, F2 hybrid generation and reproductive capacity of F1 hybrid individuals were not demonstrated.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.261-266
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• 2017

Microphysogobio koreensis is an endemic Korean freshwater fish that is protected as an endangered fish by the Ministry of Environment in Korea. In this study, we attempted to investigate the spawning period and spawning characteristics of M. koreensis to obtain basic information for its conservation. Though natural and histological observation, the spawning season occurred between April and May, with peak spawning occurred in early May when the water temperature was $20{\sim}23^{\circ}C$. During the spawning season, males had a bright-orange body and a thick red horizontal line from the rear of the operculum to the caudal peduncle, along with a lateral line, while females had a dark brown body. Nuptial organ had not appeared. The number of eggs in the ovaries was 10,705~22,165 ($15,573{\pm}4,274$). The number and appearance ratio of mature eggs were 1,100~5,920 ($3,383{\pm}2,126$) and 10.3~44.8% ($22.4{\pm}15.6$), respectively. And the size of mature eggs was 0.60~1.00 mm ($0.74{\pm}0.06$).

• Development and Reproduction
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• v.20 no.2
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• pp.109-118
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• 2016

This study monitored the morphological development of embryo, larvae and juvenile yellowtail kingfish, Seriola lalandi, for their aquaculture. The fertilized eggs obtained by natural spawning were spherical shape and buoyant. Fertilized eggs were transparent and had one oil globule in the yolk, with an egg diameter of $1.35{\pm}0.04mm$ and an oil globule diameter of $0.32{\pm}0.02mm$. The fertilized eggs hatched 67-75 h after fertilization in water at $20{\pm}0.5^{\circ}C$. The total length (TL) of the hatched larvae was $3.62{\pm}0.16mm$. During hatching, the larvae, with their mouth and anus not yet opened. The yolk was completely absorbed 3 days after hatching (DAH), while the TL of post-larvae was $4.72{\pm}0.07mm$. At 40 DAH, the juveniles had grown to $30.44{\pm}4.07mm$ in TL, body depth increased, the body color changed to a black, yellow, and light gray-blue color, and 3-4 vertical stripes appeared. At 45 DAH, the juveniles were $38.67{\pm}5.65mm$ in TL and $10.10{\pm}0.94mm$ in body depth. The fish were green with a light orange color, with 7 faint green-brown stripes on the sides of their body. At 87 DAH, the juveniles had grown to 236.11 mm in TL, 217.68 mm in fork length, and 136.5 g in weight. The fish resembled their adult form, with a light yellow-green body color, loss of the pattern on the sides of their body, and a yellow coloration at the tip of the caudal fin.

• Development and Reproduction
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• v.21 no.2
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• pp.121-130
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• 2017

4-Nonylphenol (NP) is a surfactant that is a well-known and widespread estrogenic endocrine disrupting chemical (EDC). Although it has been known that the affinity of NP to ERs is low, it has been suggested that low-dose NP has toxicity. In the present study, the endocrine disrupting effects on reproduction, and the weight of gonads, epididymis, and uterus were evaluated with the chronic lower-dose NP exposing. This study was designed by following the OECD test guideline 443 and subjected to a complete necropsy. In male, NP had an effect on the weight of the testis and epididymis in both $F_0$ and $F_1$. In females, NP decreased the weight of ovary and uterus in $F_0$ but not in pre-pubertal $F_1$ pubs. Fertility of male and female in $F_0$ or $F_1$ was no related with NP administration. The number of caudal-epididymal sperm by body weight (BW) was not different between groups in both $F_0$ and $F_1$. Besides, the difference of the sperm number between generations was not detected. The number of ovulated oocytes was similar between groups in $F_0$, but significantly decreased in NP 50 group of $F_1$. The litter size and sex ratios of offspring in $F_1$ and $F_2$ were not different. The accumulated mating rate and gestation period were not affected by the NP administration. Those results shows that chronic lower-dose NP administration has an effect of endocrine disruptor on the weight of gonads and epididymis of $F_0$ and $F_1$ but not in reproduction. Based on the results, it is suggested that chronic lower-dose NP exposing causes endocrine disruption in the weight of gonad and epididymis but not in the reproductive ability of next generations.

• The Journal of Internal Korean Medicine
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• v.19 no.1
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• pp.114-133
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• 1998

In order to investigate the effects of Alcohol-Steamed Rhei Rhizoma and Row Rhei Rhizoma on varied extract time in both endotoxin-induced blood stasis model(hereafter Endotoxin Model) and hydrocortisone acetate-induced blood stasis model (hereafter HA Model), Half of rats were treated with endotoxin(0.4mg/kg, single Ⅳ, into caudal vein) for Endotoxin Model. Thereafter, they were orally administrated water extract of Alcohol-Steamed Rhei Rhizoma or Row Rhei Rhizoma, which were boiled during 30, 60, 120 minute, respectively. Finally, the number of platelet, fibrinogen, prothrombin time, hematocrit, the number of RBC and WBC were measured after sacrifice. The remainder rats were treated with hydrocortisone acetate(10mg/kg, daily IM for 7 days into the muscular rump) for HA significantly decreased. Together, they were orally administrated for 7 days water extract of Alcohol-Steamed Rhei Rhizoma or Row Rhei Rhizoma that were boiled above methods Finally, the number of platelet, fibrinogen, prothrombin time, hematocrit, the number of RBC and WBC were measured after sacrifice. The results were summarized as follows : 1. The number of platelet was significantly increased in boiled water extract for 30 min of Row Rhei Rhizoma group as compared with that of control group in Endotoxin Model. 2. Fibrinogen level was significantly increased in all administration groups as compared with that of control group in Endotoxin Model. It was significantly increased in all administration groups except boiled water extract for 30 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in HA Model. 3. Prothrombin time was significantly shortened in boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 120 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in Endotoxin Model It was significantly shortened all administration groups as compared with that of control group in HA Model. 4 Hematocrit was significantly increased in all administered groups except boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 30 min of Row Rhei Rhizoma group as compared with that of control group in Endotoxin Model. It was significantly increased in all administration groups as compared with that of control group in HA Model. 5. The number of RBC was significantly decreased in boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group, boiled water extract for 120 min of Alcohol -Steamed Rhei Rhizoma group and boiled water extract for 30 min of Row Rhei Rhizoma administered group in Endotoxin Model. It was significantly increased boiled water extract for 30 min of Row Rhei Rhizoma group and boiled water extract for 60 min of Row Rhei Rhizoma group in HA Model as compared with data of control group. 6 The number of WBC was significantly decreased in all administered groups except boiled water extract for 30 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in HA Model.

• Journal of the Korean Society of Radiology
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• v.11 no.2
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• pp.79-85
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• 2017

The purpose of this study is to investigate the cause analysis according to the difference between the pre exposure tube voltage and actual exposure tube voltage in mammography in connection with breast pressure thickness, breast size and body mass index and to find the improvement. The study tracked 377 women age 40 and older among the mammography examiners conducted by the National Health Insurance Corporation. It was analyzed that breast pressure thickness, breast size and body mass index according to the difference between the pre exposure tube voltage and actual exposure tube voltage among the parameters of dose report been sent to the picture archiving communication system with reference to the image with cranio-caudal projection in mammography. As are result, it shows that the thicker the breast thickness, smaller the breast size and lower body mass index, the higher the difference of tube voltage. In conclusion, the minimum tube voltage of mammography machine should be reset in order to set the tube voltage according to breast pressure thickness and breast size that are suitable for our country in mammography, in addition, it was considered that radiologist should make an effort to reduce radiation exposure and make a good quality image with reducing the difference of mammography condition by making a correct exposure condition in case of examining the patients with thin breast pressure and small breast size.

• Korean Journal of Ichthyology
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• v.4 no.2
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• pp.31-43
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• 1992

The blenniid fish, Entomacrodus stellifer light(Herre) is distributed in the coastal waters of southern Japan and south-eastern Korea. Matured adults of blenniid fish were collected from the rocky shore of Namchun-dong, Nam-gu, Pusan, Korea in July, 1991. The observations were made on the morphology and skeletal development of the reared larvae and juveniles. The lavae reached 5.80mm in mean total length(MTL) in 10 days after hatching. A this time the larvae have absorbed the yolk completely and became postlarvae. Melanophores are distributed on the fin membrane of the lower part of pectoral fin and ventral margins of tail. The larvae averaged 6.20mm in TL and the caudal notochord flex at $45^{\circ}$ in 13 days after hatching. The part of the fin-fold of the future dorsal and anal fins became high. The lavae reached juvenile stage in 31 days after hatching and attained 15.80mm in MTL, and all fin-rays was formed. Ossification of the cranium took place at 6.20mm of MTL(11 days after hatching) in parasphenoid. Vertebrae began to develop from the anterior end to ossify posteriorly. Ossification of all bones nearly completed when the larvae reached to 15.80mm in MTL (31 days after hatching).