So, most labs subculture their cells into a new vessel. This subculture is also known as a âpassage.â A passage number is the number of times a cell culture has been subcultured, and knowing the passage number can make or break an experiment.All cell cultures start somewhere; this âsomewhereâ is the reference strain, or reference culture.n a large, busy lab, itâs entirely possible to lose track of how many passages your cell culture has gone through. Keep a record, both on the vessel and in your computer or a notebook. The easier it is to check on passage number, the less likely youâll be working with altered cells.
Continued rises in the price of silver increased the hoardingâmany early Kennedy half dollars have been melted for their silver. Starting with 1965-dated pieces, the percentage of fine silver was reduced from 90% to 40% (silver clad), but even with this change the coin saw little circulation.
Morgan silver dollars are one of the most popular series of United States coins amongst collectors. The coin is named after it's designer, George T. Morgan. They were struck in every year from 1878 to 1904 and revived again in 1921 for a single year.