What are the types and functions of access control systems?

In order to prevent the following problems when culturing cells, the cells will be cryopreserved: *, the transformed cells produce transformation. Second, pollution. Third, there are specific restrictions on the proliferation or physiological characteristics of strained cells, and they can only be propagated in a certain number of generations or carried out specific experiments. One of the current possible solutions to these difficulties is the cell cryopreservation method. Store the frozen cells in a cryotube, take out a part of them for some necessary inspection, and other frozen cells are taken out and thawed when needed. conduct experiment. The method can also save labor and material resources spent in the subculture, and can prevent frequent accidents and loss of cell beads during the culture. Therefore, the cryopreservation method is one of the basic techniques in research.

1. The survival rate of cells after cryopreservation will decrease. The cooling rate during freezing, the preservation temperature, the rate of temperature increase during thawing, and the type and concentration of the cryopreservation solution added can all affect the cell survival rate.
2. Generally, freeze slowly below 4 ° C and store in liquid nitrogen (-196 ° C).
3. Thaw quickly at 37 ℃.
4. Protective agent (antifreeze): Add glycerol (about 10%) or dimethy1sulfoxide (DMSO) (5-10%).
5. Some cells cannot obtain a high survival rate when using the above method. At this time, it is necessary to consider the mechanism that may damage cells, the role of additives, etc. to find the appropriate conditions to correct.

1. Cells in the proliferation stage (90% full), cultivated in several dishes.
2. Freezing medium (twice): Add triple serum and 15% DMSO to the medium and store in the refrigerator.
3. Freezing tube, poly dragon container, aluminum ampoule support rod.

1. Prepare 2 x 107cells / ml cell suspension.
2. Freezing medium (twice): Dissolve DMSO in lukewarm water and mix in the medium to 15% (v / v). This is a solution with double the concentration of DMSO. It must be prepared before the experiment and placed in the refrigerator after preparation. The amount used must be equal to the amount of cell suspension; it should be maintained at 4 ° C during use.
3. Dispense: Add 0.5ml (1/2 volume of freezing tube) freezing medium (2 times) and 2 x 10 (7th power) cells / ml cell suspension to the freezing tube; mix in equal amount . After tightening the cap, seal the tape with tape.
4. Recording label: Use antifreeze marker pen to write the required items such as cell name, generation, frozen year, month and day on the freezing tube.
5. Place in a cooled Poly Dragon container, and place in an ultra-low temperature tank at -80 ° C overnight.
6. Put in a liquid nitrogen container and store it: Put a freezing tube on the support rod and put it into the container quickly.

Unsaturated polyester resin is a polymer obtained by the polycondensation reaction between polyacids and polyalcohols. The development of water is the by-product of this polycondensation process. Specifically, the Unsaturated polyester resin, also known by the English acronym UPR, is an easily printable liquid polymer which, once cured (cross-linked with styrene, by the use of particular substances, organic peroxides, named hardeners), keeps the solid shape taken in the mold. The items so realized have exceptional strength and durability characteristics. Unsaturated polyester resins are mostly used in combination with reinforcing materials such as glass fibres, that give life to the FRP (an acronym deriving from the English), a polyester reinforced with glass fibres, better known with the name of fiberglass.

Unsaturated Polyester Resin

Unsaturated polyester resin

HENAN CHUANGE INDUSTRY CO., LTD , https://www.chuangegroup.com