IUPAC Glossary of Terms Used in Toxicology - Terms Starting with Q

quality assurance
All those planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality.

1. Operational techniques and activities that are used to fulfill requirements for quality.
2. In toxicology, procedures incorporated in experimental protocols to reduce the possibility of error, especially human error.
   Note: This is a requirement of good laboratory practice.

quantal
Describing a condition that can be expressed only as occurring or not occurring, such as death.
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quantal effect
all-or-none effect
antonym graded effect
Condition that can be expressed only as ‘occurring’ or ‘not occurring’, such as death or occurrence of a tumor.

quantitative structure-activity relationship (QSAR)
Quantitative structure-biological activity model derived using regression analysis and containing as parameters physicochemical constants, indicator variables or theoretically calculated values.
Note: The term is extended by some authors to include chemical reactivity, i.e. activity and reactivity are regarded as synonyms. This extension is discouraged.
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quantitative structure metabolism relationship (QSMR)
Quantitative association between the physicochemical and (or) the structural properties of a substance and its metabolic behavior.
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