• Korean Journal of Ichthyology
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• v.6 no.2
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• pp.206-221
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• 1994

Morphometrical data for diploid and induced triploid cherry salmon, Oncorhynchus masou were analyzed prior to the spawning season to compare their commercial values. The following traits were measured with the diploids and induced triploids : ungutted and gutted body weight; body length; dressing percentage; condition factor; gonad weight and gonad index; belly thickness; viscera weight; viscera index; body circumference at the pelvic, dorsal and anal fins; area of the cross sections at the pelvic and dorsal fins; two belly thickness traits measured on each cross section; total height, height and width of each cross section; three body shape traits; and nine cross section shape traits. Body length and body weight of diploids were larger than those of induced triploids and dressing percentage, gonad weight, gonad index, viscera index, and liver index were also larger in diploids. However, induced triploids showed higher values in one belly thickness trait and some section shapes than diploids. Differences in body traits were due to the sterility of induced triploids. Therefore, induced triploid cherry salmon appears to have greater potentials for the commercial values than their diploids.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.115-124
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• 2006

Gonad index, spermatogenesis and the reproductive cycle of Meretrix petechialis were investigated by cytological, histological observations. Monthly changes in the gonad index coincides the gonadal development. The morphology of the spermatozoon had a primitive type and is similar to that of other bivalves having a short mid-piece with five to six mitochondria surrounding the centrioles. The morphology of the sperm nucleus type and the acrosome shape of this species were cylindrical type and cap-like shape, respectively. The spermatozoon was approximately 40-45 ${\mu}m$ in length including the sperm nucleus length (about 1.50 ${\mu}m$), acrosome length (0.60 ${\mu}m$) and tail flagellum. The axoneme of the tail flagellum consisted of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail showed 9 + 2 microtubular arrangement. The spawning period was from June to September and the main spawning occurred from July to August when seawater temperatures were higher than $20^{\circ}C$. The reproductive cycle of this species could be categorized into five successive stages: early active stage (February to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to September), and spent/inactive stage (September to February).

• The Korean Journal of Malacology
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• v.26 no.3
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• pp.201-209
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• 2010

The investigated of survival rate, sex ratio, condition index, gonad development frequency, gonad index, fertilization rate, hatching rate and time required development of D shape larvae of the ark shell, Scapharca subcrenata. Survival rate was lower in heating group compared with control group (P < 0.05). Sex ratio (female:male) observed 1:0.97 in control group, 1:0.62 in heating group. Condition index was significantly higher in heating group than control group (P < 0.05) and higher increased more than water temperature $17^{\circ}C$ of heating group. Gonad development observed slow in control group but more than ripe stage 80% in heating group (21-28 day, $20^{\circ}C$). Gonad index was higher in heating group compared with control group (P < 0.05). Fertilization rate and hatching rate of the ark shell was observed $82.17{\pm}3.55%$ and $63.57{\pm}2.36%$, respectively. The time required development of D shape larvae of the ark shell was observed 15 hour after fertilization. The suggested that results of the ark shell by heating were effective sex maturation and normal egg development.

• Journal of Aquaculture
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• v.8 no.4
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• pp.327-341
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• 1995

A Study was conducted by using a histological method to examine gonadal development in diploid and triploid mud loach, Misgurnus mizolepis. Shape of ovaries from both groups looked like a single mass however, size of triploid ovary was significantly smaller than that of diploid ovary. Testis of triploid was also similar that of diploid in shape, but it was smaller than that of diploid. Ovarian development and oogenesis in diploid were significantly more rapid than those process in triploid, and first matured eggs were observed 100-days after hatching (SL, 5.68cm). Triploid ovary from hatching to 9-month-old had external appearance of undeveloped gonad and a few of oocytes of perinucleolus stage. However, normal matured eggs like those of female diploid were observed in one 5year-old triploid fish ovary examined. Although testicular development and sperrnatogenesis of diploid were prosperous sexually, testicular development of triploid were rather retarded compare to their male diploid counterpart in spermatogenesis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.455-461
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• 2004

The morphological and histological changes of gonad in ridgetail prawn (Expalaemon carinicauda) were examined with the development of the external genitalia. The samples were collected monthly in Hampyung Bay on the western coast of Korea, from January to December 2003. The ovaries lie on the dorsal side of the female prawns thorax. The ovary cavity is located below the heart and above the hepatopancreas. The anterior part of the ovary is round and fused, and the posterior part has a pair of tubular structures. Testes are bilaterally symmetrical; the anterior part shows fused feature, and the posterior part consists of a pair of tubules. Based on histological examination, ripe eggs and spermatozoa were observed when mature females and males reach a length of about 14.9 and 11.5 mm CL, respectively. The immature female are almost same shape and structure with matured one in the endopod of first pleopod and appendix interna of the second pleopod, except the number of setae, and appear to be structurally complete after females reach a length of about 14.9 mm CL. The appendix masculina reaching beyond the distal end of the appendix interna of the second pleopod after males reach a length of more than 5.5 mm CL and a fully developed appendix masculina and appendix interna of the second pleopod appear up to a length of 11.5 mm CL.

• Journal of Radiation Industry
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• v.9 no.2
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• pp.69-75
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• 2015

Purpose: The gonad shielding is used to minimize the impact of the exposure to gonads when Abdomen, Pevis and Hip X-ray inspections are conducted on radiation impressionable pediatric patients. By the way, the gonad is palpable difficult and impossible to check visually because it's a sensitive area, so tests are conducted with the approximate location of shielding, thereby appearing problems of not shielding gonads accurately. Accordingly, this study produced shields by age and gender of pediatric patients and studied the method of positioning shields with ASIS as a reference point without palpable sensitive areas, and tried to evaluate its usability. Materials and methods: The study surveyed 30 pediatric patients by gender and age, who came and got inspected in Department of Radiology, our hospital from February 2012 to January 2014 and obtained the value of tolerance by measuring the average size of the pelvis using the distance measurement function of Infinitt Piview with the images stored in the PACS and producing shields by age and gender of pediatric patients and specifying the areas at random for the comparative analysis of pre- and post-using. It calculated the technology statistics($mean{\pm}SD$) with the value of tolerance measured the length using SPSS 12.0 statistical program. Results: As for boys, differences in the tolerance range of pre- and post-using shields were 2.69 mm in case of 1 year old, 2.58 mm in 2 years, 2.37 mm in 3 years, 2.815 mm in 4~5 years, 2.043 mm in 7~10 years, and as for girls, 1.92 mm in 1~2 years, 1.75 mm in 3~4 years, 2.52 mm in 5~6 years and 1.93 mm in 7~10. After analyzing the pre- and post-using shields for all of boys and girls, there were statistically significant differences(P<0.050). Conclusions: It is considered that we can minimize the exposure to gonads and get a better video for diagnosis in testing high biological impressionable pediatric, if we use shields correctly with ASIS as a reference point considering its shape and size by age and gender in Abdomen, Pevis and Hip X-ray inspections.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.119-124
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• 2008

Reproductive ecology of the snow crab Chionoecetes opilio was investigated in terms of the reproductive organs, abdominal flap, fecundity, and maturity. Specimens were collected with gill nets and trawls from June 2002 to May 2003 in the eastern waters of Korea. The female and male C. opilio are distinguished only by the shape of the abdominal flap, which is triangular in males and circular in females. The gonads of female and male crabs are generally X-shaped. The male gonad is white, while the female gonad appears milk-white after spawning and then turns from light orange to dark orange with maturation. The female gonads matured from June, and mature and immature groups could be distinguished from December to February or March. Brooding eggs changed from bright orange to dark brown with formation of the compound eye immediately before hatching. Accordingly, the main spawning season is February and March. The minimum maturity carapace width of female crabs was 61.1 mm, and the mean fecundity is about 108,300 eggs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.48-54
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• 2017

The ecological characteristics of Pseudoblennius cottoides were investigated off Dolsan Island, Yeosu, Korea, from June to December, 2001. Their habitats were the reef zone and surrounding embankment which was covered with seaweeds. Their range of total length (TL) was 6.10-8.40 cm (n=15), and the individuals (over 8.10 cm) of them accounted for in June. It was 8.60-15.7 cm (n=67), and the individuals 11.1-12.0 cm in TL accounted for in October, 2001. The female to male sex ratio was 1:0.48 (n=185). The gonads were in the shape of a rod and the ovaries were large in size. In June, the histology of the seminiferous tubules was observed. In August, the testicles appeared. In October, spermatocyte was observed in the testes, and ovaries were observed in relation to circumference popularity and oocyte.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.159-165
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• 2011

The anatomy and ultrastructure of the digestive diverticulum of Saxidomus purpuratus were described using light and electron microscopy. The digestive diverticulum of dark green color was situated on the gonad and connected to stomach by a primary duct. Digestive diverticulum is composed of numerous digestive tubules. The epithelial layer of digestive tubule, which is simple, is composed of basophilic cells and digestive cells. Basophilic cells are columnar in shape, and the electron density is higher than that of the digestive cell. The cytoplasm has a well-developed endoplasmic reticulum, tubular mitochondria, Golgi complex and membrane-bounded granules of high electron density. Digestive cells are columnar in shape, with development of microvilli on the free surface. Pinocytic vasicles, lysosomes and numerous mitochondria were observed in the apical cytoplasm of digestive cells. The results of this study suggest that basophilic cells and digestive cells in the digestive tubule are specialized in the extracellular and intracellular digestions, respectively.

• The Korean Journal of Malacology
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• v.31 no.1
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• pp.27-34
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• 2015

The anatomy and ultrastructure of the digestive diverticulum of Tegillarca granosa were described using light and electron microscopy. The digestive diverticulum was situated on the gonad and connected to stomach by a primary duct. Digestive diverticulum is composed of numerous digestive tubules. The epithelial layer of digestive tubule, which is simple, is composed of basophilic cells and digestive cells. Basophilic cells are columnar in shape, and the electron density is higher than that of the digestive cell. The cytoplasm has a well-developed endoplasmic reticulum, tubular mitochondria, Golgi complex and of membrane-bounded granules of high electron density. Digestive cells were classified into three types. According to cell shape, electron density and cell organelles. However, three types of epithelia was same that striated border was observed in free surface and lysosome was observed in cytoplasm. The results of this study suggest that basophilic cells and digestive cells in the digestive tubule are specialized in the extracellular and intracellular digestions, respectively.