Fluorescence-Activated Cell Sorting (FACS) is a laboratory method of analysing and sorting cells based on their features such as size, granularity, and molecules present on the cell surface. A common output from a FACS machine is two dimensional dot plots showing two of the measured characteristics of the cells (see the example below). In these plots, each dot represents a cell and the density of dots is represented by changing the colours from blue through to red. These plots are then ‘gated’ where the researcher will draw circles around what they believe to be the cells of interest (e.g. the red circles/ellipses in panel B of figure), and the number of cells in these circles can be calculated. Professor Lu had a hypothesis that exposing cells to chemical X would reduce the size and granularity of the cell. To investigate this, Professor Lu first analysed cells with FACS, and used gating to estimate the proportion of cells that had both a low size, and low granularity (red continuous circle in figure above). Professor Lu then exposed half of the cells to chemical X, and the other half to a neutral solution (the control group). Professor Lu reanalysed both samples again and used FACS gating to estimate the proportion of cells that were both small, and of low granularity. Professor Lu observed that the proportion of cells that were small and of low granularity increased by a significant amount in those cells exposed to chemical X. The proportion in the control group remained approximately the same. When a paper describing the study was submitted for publication, a reviewer criticised the study and said that the subjective nature of gating at the beginning of the study may have biased the experiment and resulted in an observed effect of chemical X when in fact there was none. Question a): Do you agree with this criticism? Argue clearly why or why not. A second reviewer also criticised the study, but this time because of the subjective nature of gating at the end of the study and that this may have resulted in an observed effect of chemical X when in fact there was none. Question b): Do you agree with this criticism? Argue clearly why or why not. View Less >>
The author statements with regard to article is not convincing from reader’s perspective but it is important to know the author’s criticism behind the article and use of the technique FACS.In this article it shows few parameters which are required to be carried out initially before starting the Get solution

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