Importance of the in vitro model of tissues or organs is now evident in tissue engineering and cell biology research. Till now, two-dimensional culture systems have been using for in vitro cell culture, and have contributed to cell function studies despite their limitations. Three-dimensional (3D) culture has been utilized in cell biology research because it appears to mimic morphology and physiology of cells in living tissues and organs, unlike conventional monolayer cell culture. In our laboratory, we are developing 3D culture systems of bovine endometrial cells as a tool for the analysis of uterine endometrial functions. Among them, this lecture introduces spheroid culture and Matrigel culture. 1. Spheroid culture; Spheroids are a spherical mass composed of cells and extracellular matrices (ECMs). We have regenerated multicellular spheroids composed of bovine endometrial stromal and epithelial cells using ascorbate (1). Expression of MMPs, which are key enzymes for the tissue remodeling of the endometrium, were analyzed using the spheroid. E2, P4 and type-I IFN did not affect the gene expression of MMPs in the spheroid. However, treatment of type-I IFN increased the clearance of MMPs in the supernatant. These results suggest that IFN indirectly regulates endometrial tissue remodeling through clearance of MMPs. 2. Matrigel culture; It is reported that cells form lumens automatically by culturing cells in Matrigel (2). Matrigel is a solubilized basement membrane extracted derived from EHS mouse sarcoma cells. The bovine endometrial epithelial cells cultured in 15% Matrigel formed a circular or elliptical gland-like structure. Gene expressions of glandular epithelial specific factors (FOXA2, SERPINA14 and GRP) were significantly high in the Matrigel, compared to the monolayer cultured cells, except FOXA2. Further, SERPINA14 expression was affected by neither P4 nor IFN. However, when epithelial cells in Matrigel were co-culture with stromal cells, SERPINA14 expression increased significantly in the treatment of both P4 and IFN. These results suggest that bovine endometrial epithelial cells cultured in Matrigel show properties similar to the glandular epithelial cells in vivo, and regulated by the factors produced by the stromal cells. Finally, by using these 3D culture systems, it becomes possible to clarify not only factors regulating embryo elongation and implantation but also regulation of their expression. It will be able to reveal the mechanism of the embryo elongation and implantation to contribute to the improvement of the embryo transplantation technique. (1) Yamauchi N, Yamada O, Takahashi T, Imai K, Sato T, Ito A, Hashizume K. A three-dimensional cell culture model for bovine endometrium: regeneration of a multicellular spheroid using ascorbate. Placenta. 2003; 24(2-3):258-69. (2) Eritja N, Llobet D, Domingo M, Santacana M, Yeramian A, Matias-Guiu X, Dolcet X. A novel three-dimensional culture system of polarized epithelial cells to study endometrial carcinogenesis. Am J Pathol 2010; 176:2722-2731.

The high pressure compaction without internal lubricant and the high green density even with the pore free density were achieved by the newly developed die wall lubricant for warm compaction. This developed die wall lubricated warm compaction followed by high temperature sintering resulted in not only the superior mechanical property but also the low dimensional change. In this paper, the effects of increasing the green density on the sintered density, the dimensional change and the mechanical property are mainly discussed

벼를 가해하는 4종의 멸구매미충 즉 애멸구, 끝동 매미충, 벼멸구 및 흰등멸구의 경제적 중요성에 대한 지역적 차이를 수원과 남부 그리고 남서 해안지역에서 수행한 개체군의 밀도조사를 토대로 분석 검토하였다. 한국에서 년중 볼 수 있는 애멸구와 끝동 매미충의 경제적 중요성은 중부지방이 덜한 것으로 보인다. 이는 겨울의 추운 기후조건, 벼, 보리의 경작 방법 및 거미류 같은 천직에 의해서 지연 치사작용이 효과적으로 일어나는 때문인 것으로 믿어진바. 그러나 남부지방에서는 겨울이 덜 춥고 벼, 보리의 경작방법이 이 두 해충의 생활환과 기주식물의 계절적 변천 양자의 재일성에 유리한 편이어서 이들의 경제적 중요성은 확실히 크다고 하겠다. 한국에서 원동을 하지 못하는 벼멸구와 흰등멸구의 매년 첫 발생개체군은 동지나해를 건너 원거리를 이동해 오는 것들에 기인된다. 이들의 이동과 관련을 갖고 있는 기상요소로 해서 이동되어오는 벼멸구와 흰등멸구의 양은 중부지방보다 남부지방에서 월등히 많다. 그러므로 벼를 가해하는 멸구매미충류에 대한 종합방제책으로 중부와 남부지방 별로 지침을 달리 세울 것이 요망된다.