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The following formulas can be used to calculate the volumes of solute (V solute) and solvent (V solvent) to be used: [1] = = where V total is the desired total volume, and F is the desired dilution factor number (the number in the position of F if expressed as "1/F dilution factor" or "xF dilution"). However, some solutions and mixtures take up ...
Coulter and CASY counters are much cheaper than flow cytometers, and for applications that require cell numbers and sizes, such as cell-cycle research, they are the method of choice. Its advantage over the methods above is the large number of cells that can be processed in a short time, namely: thousands of cells per second. This offers great ...
Plaque formation can take 3–14 days, depending on the virus being analyzed. Plaques are generally counted manually, and the plaque count, in combination with the dilution factor of the infection solution (the sample initially applied to the cells), is used to calculate the number of plaque forming units per sample unit volume (PFU/mL). The ...
Conversely, in an indirect dilution assay the dose levels are administered at fixed dose levels, so that the response is a stochastic variable. In some assays, there may be strong reasons for believing that all the constituents of the test preparation except one, are without any effect on the studied response of the subjects.
V = air or gas volume of the closed space or room in cubic feet, cubic metres or litres; Q = ventilation rate into or out of the room in cubic feet per minute, cubic metres per hour or litres per second; C initial = initial concentration of a vapor inside the room measured in ppm; C final = final reduced concentration of the vapor inside the ...
A prior understanding of the microscopic anatomy of the organism can give a better understanding of how the observed CFU/mL relates to the number of viable cells per milliliter. Alternatively it is possible to decrease the average number of cells per CFU in some cases by vortexing the sample before conducting the dilution. However, many ...
A dilution of the cells to be counted is prepared and mixed with Trypan blue, this is normally the stain of choice because it is taken up by dead cells and actively excluded from live cells. Once the cells have been stained, they are counted using a hemocytometer, then a calculation is carried out to the original concentration of live cells. [1]
The volume of the squares counted is the one shown in the table at the top, depending on the size (see figure on the right). The number of cells counted is the sum of all cells counted across squares in one chamber. The proportion of the cells counted applies if not all inner squares within a set square are counted (i.e., if only 4 out of the ...