• Applied Microscopy
• /
• v.39 no.3
• /
• pp.237-243
• /
• 2009

Chinese minnow, Rhynchocypris oxycephalus is a teleost belonging to Leuciscinae, Cyprinidae. The oogenesis and ultrastructure of egg envelope in Chinese minnow were investigated by light and electron microscopes. The ovary was of white yellowish and ellipsoidal shape with the major axis 30 mm and the minor axis 7mm. Cytoplasm of oogonia was basophilic and many nucleoli were located at inside of nuclear membrane. In primary oocytes, yolk vesicles were distributed only in the marginal area and egg envelope was not formed on the outside of an egg. In secondary oocytes, the egg envelope was formed and yolk vesicles in the cytoplasm were increased than the earlier stage. The basophilic substance of cytoplasm was changed to acidic. In case of matured egg, thickness of egg envelope and size of egg were increased. The yolk vesicles were changed to yolk mass in accordance with development. The outer surface of egg envelope was covered by microvilli-structures, and had a micropyle on the area of animal pole. Egg envelope consisted with 2 layers, an adhesive outer layer with microvilli-structures and fibrillar inner layer. In conclusion, the oogenesis of Chinese minnow was characterized by the increase in cell size, the formation and accumulation of yolk, and the decrease of basophilic substance in the cytoplasm. The oogenesis of Chinese minnow seems to share common patterns in Cyprinidae, but these ultrastructural unique characters of egg envelope can be utilized in taxonomy of teleost.

• Korean Journal of Materials Research
• /
• v.6 no.3
• /
• pp.333-340
• /
• 1996

p-type(100) 실리콘 기판과 TiN(50nm)/Si 기판에 dimethylethylamine alane(DMEAA)을 반응소스로 하여 알루미늄을 증착시켜 증착온도와 유량, 반송가스 종류에 따른 방향성, 증착속도, 미세구조 변화에 대해 연구하였다. 알루미늄의 증착속도는 기판온도, 반송가스 종류 및 유량에 따라 100-650mn/min으로 다양하게 조절되었다. DMEAA의 증착 활성화에너지는 TiN 기판에서는 약 0.leV이었고 Si와 SiO2 기판에서는 각각 약 0.23eV, 0.24eV이었다. 알루미늄 박막의 방향성은 증착속도의 감소에 따라 (200)에서 (111)방향으로 변하였다. 증착된 알루미늄 박막의 불순물 함량은 산소의 경우 0.2at%, 탄소의 경우 1.8at.%이었다. DMEAA 소스에 의한 알루미늄의 증착속도는 반송가스가 Ar 일 때 보다 H2 가스를 사용하면 증착속도가 크게 증가하였으며 이는 반송가스에 의해 SiO2표면의 흡착 H 농도가 증가하고 흡착 H가 소스 가스와 반응하여 핵생성 site 로 작용하는 것으로 생각된다. 알루미늄 박막의 비저항은 표면 미세조직에 크게 영향을 받으며 그 값은 약 3-7$\mu$$\Omega$cm이었다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.12 no.5
• /
• pp.247-252
• /
• 2002

$(Pb_{1-x}La_x)TiO_3$ (x = 0.1) thin films were prepared on ITO-coated glass substrates by metal organic chemical vapor deposition using ultrasonic spraying. Effects of the post-annealing and the seeding layer on crystallization, microstructures and electrical properties of thin films were investigated. Dielectric constants of films increased due to the modification of crystallization and the changing of a surface morphology by applying the post-annealing. In addition, as the application of PT seed- ing layer offered nucleation sites to PLT thin films, electrical properties of films were enhanced by the increase of crys-tallinity and grain size. The dielectric constant of the films post-heated for 60 min and with a seeding layer was 213 at 1 kHz.

• Journal of Sericultural and Entomological Science
• /
• v.31 no.2
• /
• pp.113-120
• /
• 1989

A new microsporidia (S85) was isolated from the silkworm, Bombyx mori L. in Suwon, Korea in 1985. The electron microscopic observation of the fine structure of the spore was studied for the characterization of the new microsporidia and its taxonomic position. The sporewall was composed of three different electron dense layers and the spore surface was rouph and wrinkled. The polaroplast has two parts which differed in the arrangement of the lamellae. The polarfilament was isofilar with thirteen coils and it was consisted of eight concentric layers of different electron density. The spore contained a single nucleus and the pansporoblast appeared as a thin ballon-like structure surrounding the spore. The membrane was generally smooth and shown occationally wrinkled.

• Applied Microscopy
• /
• v.40 no.4
• /
• pp.253-259
• /
• 2010

The ultrastructure of sperms in testes of the pond smelt (Hypomesus nipponensis) was investigated using electron microscopes. The whitish testis was located between swim bladder and intestine. Especially, the left testis was larger than the right testis. The sperm was approximately $26\;{\mu}m$ in length. The sperm had an oval head and the acrosome was not found. The nucleus was about 400 nm in diameter and chromatin was incompletely condensed. The nuclear fossa deeply formed in sperm head and two centrioles were located in the fossa. The mitochondrium was observed only one in midpiece of the sperm and a motile flagellum consisted of an axoneme with a typical 9+2 pattern of microtubule. Also, the tail of the sperm has axonemal fins.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.31 no.3 s.258
• /
• pp.248-255
• /
• 2007

Thermal bubble formation is a fundamental process in nucleate boiling heat transfer and many microelectromechanical thermal systems. One of the established facts is that heterogeneous nucleation is originated from vapors trapped inside cavities. Based on this, we performed an experimental study on the formation of thermal bubbles from microcavity fabricated by microfabrication technology on a copper plate. The cavity was filled with aluminum particles to enhance thermal bubble formation. We observed the thermal bubble behaviors, such as bubble incipience, diameter, frequency and coalescence during nucleate boiling. The experimental data showed that the superheat required to trigger the bubble formation was significantly reduced when the cavity was filled with microparticles. We found that the initial increase of superheat led to the increase of both the departure diameter and frequency while the further increase of superheat caused multiple bubbles to coalesce resulting in the decrease of departure frequency.

• The Korean Journal of Zoology
• /
• v.35 no.1
• /
• pp.45-57
• /
• 1992

생쥐를 48시간 동안 결식시킨 후 유문결찰하여 급성미란을 유발시키고 미란형성부의 점막 내위선을 구성하는 각 세포의 구조변화와 IgA 분비세포의 분포를 관찰하였다. 미란부 점액분포의 변화는 표면상피의 손상 정도가 심해질수록 경계부의 PAS양성반응은 감소되었으며 중심부에서는 표면상피의 소실로 인하여 PAS 양성반응이 관찰되지 않았다. Glycocalyx 관찰을 위한 ruthenium red 반응에서도 경계부의 상피세포 손상이 심해짐에 따라 정단세포막 상층에 나타나는 양성반응은 감소되었고 측면과 기저면의 양성반응은 관찰되지 않은 것으로 보아 세포 손상시 tight junction은 파괴되지 않음을 알 수 있었다. 미란경계부의 미세구조변화로서, 상피세포는 손상이 진행될수록 세포질이 용해되어 공포가 형성되고 핵응축 및 정 단세포질의 점액원과립의 소실이 관찰되었으나 tight junction은 유지되었다. 반면에 점액경세포는 점액원과립의 수가 증가되고 조면소포체가 종창되어 있었다. 미란의 경계부와 중심부에서 벽세포는 다수의 소포가 출현한 후 세포내세관이 종창되었으며 그 후에 mitochondria가 파괴되었고 주세포는 주변의 벽세포가 커지면서 가장자리로 밀려나 크기가 정상보다 작아지고 조면소포체와 mitochondria가 종창을 나타내었다. IgA분비세포는 점막이 파괴된 미란부 점막하조직의 혈관 주변에 다수 존재하는 형질세포에서 확인되었다.

• The Korean Journal of Malacology
• /
• v.10 no.1
• /
• pp.1-8
• /
• 1994

동양달팽이속(Nesiohelix)에 속하는 종으로 한국에서는 유일하게 서식하고 있는 종으로알려진 동양달팽이(Nesiohelix samarangae)성체의 눈에 대하여 해부학적 및 미세구조관찰을 실시한 결과 다음과 같은 결론을 얻을 수 있었다. 동양달팽이의 눈은 각막, 무세포성의 수정체, 망막및 신경망 등으로 구성되어 있는 바 가장 복잡한 구조를 보이는 부분은 망막으로서 이의상피는 2종의 원주세포로 구성되어있다. 그 하나는 광수용세포로서 세포의 상부세포질이 원추형 또는 피라미드형의 돌기를 이루었고 그 유리표면에는 긴 감간(microvilli)이 무수히 많이 존재하고 있으며, 돌기를 이룬 세포질 내에는 용해소체의 활성이 높게 나타난다. 또한 광수용세포들의 상부세포질에는 이웃해 있는 색소세포들의 세포질 돌기들이 여러개 침입해 들어와 있다. 그리고 핵 주변의 세포질에는 수많은 photic vesicle들이 군집을 이루어 존재한다. 다른 한 종류의 세포는 색소세포들로서 광수용세포들과는 달리 세포의 상부에 원추형의 세포질 돌기가 없고 다만 그 유리표면을 따라 광수용세포의 것보다는 굵고 짧은 많은 감간이 존재하는데 두 종류의 세포들에서 뻗어나온 감간들은 서로 만나 때로 파상을 이루고 있다. 망막 상피세포층의 기저막 아래에는 신경망이 컵모양의 망막을 따라 존재한다.

• Korean Chemical Engineering Research
• /
• v.56 no.1
• /
• pp.79-84
• /
• 2018

In the present study, we performed electroporation to deliver protein into microalgae using previously developed digital electroporation system. Green fluorescence protein was successfully delivered into a live microalgae cell nucleus without cell wall removal. By investigating the effects of applied voltage on the protein delivery efficiency, optimal electroporation electric field condition was found (960 V/cm). We also investigated the delivery of Yo-Pro-1 into cell to examine the size effects of delivered materials and found that there is little size effects on the optimal condition. Finally, the implications of the present results and future work are discussed.

• Journal of Embryo Transfer
• /
• v.19 no.3
• /
• pp.191-199
• /
• 2004

This study was conducted to examine in vitro development of porcine embryos constructed by the microinjection of cultured fetal fibroblast cells into porcine oocytes matured in vitro. Single fetal donor cells were deposited into the perivitelline space of enucleated oocytes, followed by electrical fusion and activation. Activated embryos were cultured in NCSU-23 medium supplemented with 5％ FBS, at 38.5$^{\circ}C$ for 6 to 8 days in 5％ $CO_2$ and air. In experiment 1, fusion rates of nuclear transfer embryos did not differ for fetal fibroblast cells incubated in 5％ FBS + NCSU-23 or 5％ FBS + TL Heaps medium, nor did fusion rates of donor cells differ between 1-8 hr incubation durations. Fusion rates for the four treatment subclasses ranged from 72.1％ to 78.0％. In experiment 2, Pre-synchronization in medium containing 0.1 $\mu\textrm{g}$/m Hoechst 33342 an increase from 0 and 8 versus 15 h culture an increased percentage of porcine fibroblast cells in G2/M at the end of the synchronization period (12.4％, 17.5％ and 47.6％). Neither an increase in the concentration of H 33342 (0.2-1.6 $\mu\textrm{g}$/$m\ell$) nor a longer exposure time (12h, 18h and 24h) increased the proportion of porcine G2/M fibroblasts. In experiment 3, fusion rates did not differ significantly far nuclear transfer embryos constructed using donor cells cultured in 5％ FBS + NCSU-23 medium for 1-2, 6-8 or 12-14 days (60.0％, 73.3％ and 62.5％), respectively. The cleavage rate for nuclear transplant embryos using fetal fibroblast cells cultured for 1-2 days was 44.0％, significantly less than 56.7％ and 50.0％. for 6-8 or 12-14 days duration of culture, respectively. In experiment 4, the proportions of nuclear transfer embryos that developed to the $\geq$2 cell and to the blastocyst stage were not affected significantly by culture medium (5％ FBS + NCSU-23 or 5％ FBS + TL-Heaps) or by $O_2$ concentration of the culture (5％ vs 10％). Rates of development to the $\geq$2 cell stage ranged from 65.9％ to 70.1％, and development rates to the blastocyst stage ranged from 9.8％ to 12.5％ for the four treatment subclasses. Developmental rate was highest for embryos cultured in 5％ FBS + NCSU-23 under a gas atmosphere of 5％ $O_2$ in air.