• Journal of Embryo Transfer
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• v.6 no.2
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• pp.30-36
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• 1991

The method of vitnilcation has various merits. It needs neither seeding nor slow freezing. It can freeze embryo by putting it directly into liquid nitrogen at the indoor temperature to $0^{\circ}C$. The operation process is quite easy. Moreover, higher promise of survival can be expected as there is no physical damage by any lumps of ice with the exception of cells. In Kasal's experiment (1990) using EFS liquid and Kang's experiment (1991) using GFS liquid the ratio of the damaged embryo was only 2-3%. But, the method of vitrification is now on the process of improvement, and the final or united method is not yet established. At the present time, most of the major institutes all over the world are using the traditional freezing method in the preservation of mouse embryo, but it is very likely that the vitrification will prevaIl in the near future considering the various merits of it. Calves can be begotten from the embryo by means of vitriilcated preservation in the cases of cow, rat, and rabbit as well as of mouse. In addition, recent experiments have shown that vitrificated preservation was successful in the case of drosophila embryo which was much bigger than mammalian embryo, which fact tells that this method is expected to be preferably used even in the preservation of living organs in the near future.

• Journal of the Korean Society of Industry Convergence
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• v.1 no.2
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• pp.41-48
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• 1998

This experimental study describes atomization characteristics of spray-spray impingement. Effect of the impingement location and angle on the penetration and the sauter mean diameter of the impinged spray were investigated. Experiment were performed under ranging from 50kPa to 250kPa spray pressure, ranging $30^{\circ}C$ to $135^{\circ}C$ angle on the penetration and free spray. In the case of this experimental, sauter mean diameter $D_{32}$ tends to decrease and duration of film disintegration $t_f$ to decrease, when spray pressure and angle on the penetration is increased. Sauter mean diameter $D_{32}$ were about 20% to be smaller compared with a free spray to jet-jet impingement and 30% to be smaller compared with a free spray to spray-spray impingement.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.126-131
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• 2013

BGsome coating on the surface of illite powder was attempted to impart skin affinity and improve various characteristics of the powder for makeup cosmetics. BGsome is a type of hydrated liquid crystalline vesicles prepared by the hydration of 1,3-butylene glycol (BG) dissolved lecithin. BGsome droplets were coated through wet process and the coated powders were analyzed by TGA, SEM, and particle size measurements. Effect of BGsome coating on the physical properties, such as flow-ability, dispersibility, spreadability, and adhesion, were examined. The repose angle of BGsome-coated illite was decreased, which means that BGsome coating improves the flowability of the powder. Dispersibility, spreadability, and adhesion of the coated illite were also improved remarkably. The result of adhesion tests showed that the BGsome-coated illite was evenly adhered onto artificial leather surface with almost no lumps. The flowability, dispersibility, spreadability and adhesion of face powders containing the BGsome-coated illite were also improved.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.284-292
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• 2016

Water supplied through dental unit waterlines (DUWLs) has been shown to contain high number of bacteria. To reduce the contamination of DUWLs, it is essential to develop effective disinfectants. It is, however, difficulty to obtain proper DUWL samples for studies. The purpose of this study was to establish a simple laboratory model for reproducing DUWL biofilms. The bacteria obtained from DUWLs were cultured in R2A liquid medium for 10 days, and then stored at $-70^{\circ}C$. This stock was inoculated into R2A liquid medium and incubated in batch mode. After 5 days of culturing, it was inoculated into the biofilm formation model developed in this study. Our biofilm formation model comprised of a beaker containing R2A liquid medium and five glass rods attached to DUWL polyurethane tubing. Biofilm was allowed to form on the stir plate and the medium was replaced every 2 days. After 4 days of biofilm formation in the laboratory model, biofilm thickness, morphological characteristics and distribution of the composing bacteria were examined by confocal laser microscopy and scanning electron microscopy. The mean of biofilm accumulation was $4.68{\times}10^4$ colony forming unit/$cm^2$ and its thickness was $10{\sim}14{\mu}m$. In our laboratory model, thick bacterial lumps were observed in some parts of the tubing. To test the suitability of this biofilm model system, the effectiveness of disinfectants such as sodium hypochlorite, hydrogen peroxide, and chlorhexidine, was examined by their application to the biofilm formed in our model. Lower concentrations of disinfectants were less effective in reducing the count of bacteria constituting the biofilm. These results showed that our DUWL biofilm laboratory model was appropriate for comparison of disinfectant effects. Our laboratory model is expected to be useful for various other purposes in further studies.