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Serum is a kind of pure natural culture medium. As an essential nutrient in cell culture, its proper storage will directly affect the quality of serum, and even hinder cell growth. The serum is generally stored in a special media bottle. It needs to be frozen below -20 ℃ for long-term storage. How to unfreeze the serum during use?
Serum is a light yellow transparent liquid separated from the plasma after removing fibrinogen and some coagulation factors after blood coagulation, or refers to the plasma from which fibrinogen has been removed. Common sera include fetal bovine serum, calf serum, sheep serum, etc. unfrozen serum shall be operated according to the established steps:
1. When thawing serum, please follow the recommended step-by-step thawing method (-2 ℃ to 4 ℃ to room temperature). If the temperature of serum thawing changes too much (such as -20 ℃ to 37 ℃), the experiment shows that it is very easy to produce sediment.
2. When thawing the serum, please shake the media bottle regularly to make the temperature and composition uniform and reduce the occurrence of precipitation.
3. Do not keep the serum at 37 ℃ for too long. If it is stored at 37 ℃ for too long, the serum will become turbid, and many unstable components in the serum will be damaged, which will affect the quality of the serum.
The above are the specific steps of serum thawing. High temperature thawing, violent shaking, repeated freezing and thawing, and long storage time will all lead to the reduction of serum quality. It should be noted that if a whole bottle of serum cannot be used up at one time, the remaining serum should be aseptically sub packed in the media bottle and then frozen to avoid repeated freezing and thawing.
The FAI climbed 5.9 percent year-on-year in the first 11 months of 2018, quickening from the 5.7-percent growth in Jan-Oct, the National Bureau of Statistics (NBS) said Friday in an online statement.
The key indicator of investment, dubbed a major growth driver, hit the bottom in August and has since started to rebound steadily.
In the face of emerging economic challenges home and abroad, China has stepped up efforts to stabilize investment, in particular rolling out measures to motivate private investors and channel funds into infrastructure.
Friday's data showed private investment, accounting for more than 60 percent of the total FAI, expanded by a brisk 8.7 percent.
NBS spokesperson Mao Shengyong said funds into weak economic links registered rapid increases as investment in environmental protection and agriculture jumped 42 percent and 12.5 percent respectively, much faster than the average.
In breakdown, investment in high-tech and equipment manufacturing remained vigorous with 16.1-percent and 11.6-percent increases respectively in the first 11 months. Infrastructure investment gained 3.7 percent, staying flat. Investment in property development rose 9.7 percent, also unchanged.