| 摘要 |
<p>In the cattle breeding sector it has been known for several years that it is possible to preserve egg cells or embryos by introducing them into an end of a narrow tube or 'straw', which is thereafter subjected to cryogene cooling. For some species such as pigs this preservation, however, has failed to work in practice, and the invention provides for improved results in prescribing the use of still narrower tube ends which can easily, by capillary action, be loaded with a small amount (1-2 νl) of a holding liquid for the item to be cooled, and which, when dipped into the cryogene cooling medium, provides for a close cooling contact with this medium, partly through an open end connection and partly through an outer pipe end wall of a very small thickness. A high preservation quality is achieved by the associated extremely fast cooling. Preferably, the thin tube ends are provided by a pulling out of the middle portion of a thermoplastic 'mini straw', and then cutting the straw at the middle of the resulting narrowed straw length, thus leaving the opposed thicker pipe ends as convenient handle portions.</p> |
