The phrase "a difference in quantity" is correct and usable in written English.
It can be used when discussing variations or disparities in amounts or numbers between two or more items or groups.
Example: "The study revealed a significant difference in quantity between the two samples, indicating a need for further investigation."
Alternatives: "a variation in amount" or "a disparity in numbers".
I don't think it's a difference in quality, but a difference in quantity.
"There's a point at which a difference in quantity becomes a difference in kind".
It is however important in this context to emphasize that the difference we observe is a difference in quantity and kinetics and does not reflect a complete lack of MHC-I presentation as we also find detectable levels of CD8/10.4 T cells in the early phase of infection although at a lower level than CD4/10.4 T cells.
The risk-conferring property of the APOE2 allele might be due to a difference in quantity or result from functional differences of the APOE2 protein structure.
However, with lower doses of infection (i.e. 0.1 LD50 or less), the MFI by flow cytometry is below the limit of detection while the more sensitive RT-PCR method still detects the presence of viral mRNA, indicative of DC infection, and a difference in the quantity of viral load per cell.
If this hypothesis is true a difference in dopamine quantity in the albumen gland would be observed between virgin and first time mated animals.
It is worthy of note that from the diet controlled studies this variation can not be explained solely as a difference in the quantities of chromogenic agents in any one individual's diet even though abstinence from tea, coffee or red wine virtually eliminates staining from everyone.
2) The choice whether to use modeler-constructed or laboratory optical functions, or to merge constructed data with lab data, makes a difference in calculated quantities (e.g., absorption cross-sections and total flux).
There was nearly a threefold difference in quantity and in excess of a twofold difference in variety of combined F&V consumption between the highest versus lowest tertiles of F&V intake (Table 1).
That's obvious for baking, where the way you scoop flour into a measuring cup can make as much as a 20% difference in quantity.
In turn, this could result in a difference in the total quantities of viral excretions into the air from the dogs and horses.
