Recent 2 decades, including in vitro maturation (IVM), assisted reproductive technologies (ARTs) achieved noteworthy development. However the efficiency of ARTs with in vitro matured oocytes is still lower than that with in vivo oocytes. To overcome those limitations, many researchers attempted to adapt co-culture system during IVM and consequently maturation efficiency has been increased. The beneficial effects of applying co-culture system is contemplated base on communication and interaction between various somatic cells and oocytes, achievement of paracrine factors, and spatial effects of extracellular matrix (ECM) from somatic cell surface. The understanding of co-culture system can provide some information to narrow the gap between in vitro and in vivo. Here we will review current studies about issues for understanding cu-culture system with various somatic cells to improve in vitro maturation microenvironment and provide bird view and strategies for further studies.

The objective of this study was to investigate the motility and kinematics of boar sperm that while stored at 4C. The samples of fresh boar semen were place into an extender, Androhep, and stored at . In three of these samples, cryoprotectants were added. The sperm's motilities and kinematics were evaluated by using microscope () and the viability status was evaluated by using with eosin staining method. The 5 sample groups are; Goup A:Androhep (extender), stored at . Group B:Androhep (extender), stored at . Group C:Androhep (extender), + 3% glycerol (cryoprotectant), stored at . Group D:Androhep (extender), + 3% DMSO (cryoprotectant), stored at . Group E:Androhep (extender), + 3% ethylene glycol (cryoprotectant), stored at . In group A, the sperm's motility was reduced. On day one the sperm's motility was () and day 5 the motility was (). In group B, C and D the sperm's motility were reduced to 0 on day 5. In group E the sperm's percentage of motility decreased. On day one the sperm's motility was () and day 5 the motility was (). When comparing cryoprotectant in samples of boar sperm there is a slight improvement in the results when the use of Androhep Lite (extender), + 3% ethylene glycol (cryoprotectant), stored at are used. Based on these results, ethylene glycol can protect sperm from heat shock at , but not satisfactory level. However, it showed the possibilities of liquid semen preservation at by using cryoprotectant.

This study has been performed on the full density sintering of Fe nanopowder and the surface hardening by plasma ion nitriding. The Fe sintered part was fabricated by pressureless sintering of the Fe nanopowder at in which the nanopowder agglomerates were controlled to have 0.5-5 sized agglomerates with 150 nm Fe nanopowders. The green compact with 46% theoretical density(T.D.) showed a homogeneous microstructure with fine pores below 1 . After sintering, the powder compact underwent full densification process with above 98%T.D. and uniform nanoscale microstructure. This enhanced sintering is thought to be basically due to the homogeneous microstructure in the green compact in which the large pores are removed by wet-milling. Plasma ion nitriding of the sintered part resulted in the formation of '- equilibrium phase with about 12 thickness, leading to the surface hardening of the sintered Fe part. The surface hardness was remarkably increased from 176 for the matrix to 365 .