• Applied Microscopy
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• v.37 no.3
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• pp.185-198
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• 2007

Spermiogenesis in Japanese white-toothed shrew. Crocidura dsinezumi was investigated by transmission electron microscope. Spermiogenesis was divided into 12 phases 14 steps, based on the morphological features of the nucleus and change of organelles in cytoplasm. The nucleus of spermatids in Golgi (step $1{\sim}2$) phase were spherical; however, they were changed into oval in the cap (step $3{\sim}6$) phase. Flagellum appeared in the middle of acrosomal phase; on the other hand, slender and long spermatid head was formed in maturation phase. The head of spermatids faced the lumen in step 1 to step 6 (from Golgi to cap phase), but, in step 7 to step 14 (from acrosomal to spermiation phase), it turned its head to the basal lamina of the seminiferous epithelium. The nucleus and acrosome were elongated maximally in step 10. The condensation of chromatin started in late acrosomal (step 10) phase, and it was completely finished and homogenized in the middle of maturation (step 12) phase. Multivesicular body appeared near the acrosomal vacuole during the middle cap (step 5) phase, and a large number of them were observed near the Golgi apparatus in the late cap (step 6) phase. Considering all the results, the spermiogenesis might be useful information to analyse the differentiation of spermatogenic fells.

• Journal of Life Science
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• v.23 no.10
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• pp.1288-1294
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• 2013

Knowledge of morphological changes in eel larvae is very important for artificial rearing of eel larvae. In this study, we investigated the morphological structure of the head region and histological changes of the eye retina in artificially reared larvae at various stages and in glass eel just after metamorphosis. Structural changes were observed in the upper jaw (maxilla) and the lower jaw (mandible) after 100 dah (day after hatchery) and after metamorphosis. Teeth had degenerated by the time of completion of metamorphosis. Major histological changes observed in the eye retina were the formation of the outer plexiform layer and the outer nuclear layer from 100 dah larva and a change in the rod cell layer after metamorphosis. The cornea was not observed at 10 dah in the eel larva. More information is needed on the early developmental stages of eel larvae to enable mass production of glass eels. The results obtained in the present research will be useful when developing novel rearing programs for eel larvae.

• The Korean Journal of Zoology
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• v.32 no.2
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• pp.120-133
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• 1989

The paraidehyde-fuchsin(PAE)-positive neurosecretory cells in the brains of wax moth Galleria mellonella have been morphologically examined at the six different metamorphic stages. During the metamorphosis, neurosecretory cells in the brain can be found in the five unclei of pars intercerebralis, lateral region of protocerebrum, optic lobe, deutocrebrum and tritocerebrum. The five nuelel include one to seven neurosecretory cells. On the bases of cell sizes and histochemical specificities of neurosercretion within cells, all the PAF-positive neurosercretory cells included in the six different metamorphic brains can be recognized as four species of neurosecretory cells as follows; (1) large (about 25 $\mu$m), neurosecretion-parcked cell (type I neurosecretory cell), (2) large, granule-dispersed cell (type II neurosecretury cell), (3) small (about 15 $\mu$m), neurosecretion-packed cell (type III neurosecretory cell), and (4) small, granule-dispersed cell (type IV neurose-cretory cell). The three tb seven medial neurosecretory cells are included in the pars intercerebralis of the six different metamorphic brains. With the increase of days from the late larva to the adult the type I cells of medial neurosecretory cells gradually decrease in number, but the respective three type II neurosecretory cells appear in the five different metamorphic brains except in pupa 2 day before the emeregnce of the adult which has only one type II. The one to five lateral neurosecretory cells are observed in the lateral region of protocerebrum from thepupa just after pupation to the adult. The type IV neurosecretory cells are the most in number of lateral neurosecretory cells. The one type Ineurosecretory cells are included near the optic lobe of only the 4-day-old pupa. the one deutocerebral neurosecretory cell, type II, appears only in the adult. The tritocerebrum includes both three neurosecretory cells in the late larva and one neuresecretory cell in the adult. In the late larva the two tritocerebral neurosecretory cells are type Ill neurosecretory cell and the one is type IV. The remaining one tritocerebral neurosecretory cell is type IV.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 1993.03a
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• pp.3.2-3
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• 1993

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.166.1-166.1
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.201-201
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.78-78
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• 2003

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.108-111
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• 1992

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2002.05a
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• pp.109-109
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• 2002

• Journal of the Speleological Society of Korea
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• v.37 no.38
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• pp.46-78
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• 1994

동굴의 안전진단은 일반적인 민사사항에 대비하는 안전진단 만은 아니다. 즉, 동굴의 생태환경의 보전을 위한 보전책도 강구하며 특히 동굴생물의 생태유지 등의 실태를 조사하는데 그 목적이 있다고 하겠다. 사실상 동굴은 소중한 천연적인 자연자원이다. 최근에 이르러 세계의 모든 나라에서는 이와같은 지하세계의 탑승을 위한 관광개발이 활발하게 이루어지고 있다. 예를 들면 일본에서는 전국에 총93개소의 동굴들이 공개된 관광동굴로 개발되어 있다.(중략)