- 行业: Library & information science
- Number of terms: 152252
- Number of blossaries: 0
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The National Library of Medicine (NLM), on the campus of the National Institutes of Health in Bethesda, Maryland, is the world's largest medical library. The Library collects materials and provides information and research services in all areas of biomedicine and health care.
Time from the onset of exposure to the appearance of signs of disease.
Industry:Biology; Chemistry
Time required for the concentration of a reactant in a given reaction to reach a value that is the arithmetic mean of its initial and final (equilibrium) values. For a reactant that is entirely consumed it is the time taken for the reactant concentration to fall to one half of its initial value.
Note: The half life of a reaction has meaning only in special cases:
# For a first-order reaction, the half life of the reactant may be called the half life of the # For a reaction involving more than one reactant, with the concentrations of the reactants in their stoichiometric ratios, the half life of each reactant is the same, and may be called the half life of the reaction.
If the concentrations of reactants are not in their stoichiometric ratios, there are different half lives for different reactants, and one cannot speak of the half life of the reaction.
Industry:Biology; Chemistry
Time required for the concentration of a reactant in a given reaction to reach a value that is the arithmetic mean of its initial and final (equilibrium) values. For a reactant that is entirely consumed it is the time taken for the reactant concentration to fall to one half of its initial value.
Note: The half life of a reaction has meaning only in special cases:
# For a first-order reaction, the half life of the reactant may be called the half life of the # For a reaction involving more than one reactant, with the concentrations of the reactants in their stoichiometric ratios, the half life of each reactant is the same, and may be called the half life of the reaction.
If the concentrations of reactants are not in their stoichiometric ratios, there are different half lives for different reactants, and one cannot speak of the half life of the reaction.
Industry:Biology; Chemistry
Total amount of a substance administered to, taken up, or absorbed by an organism, organ, or tissue.
Industry:Biology; Chemistry
Toxicity which follows a single exposure to a substance.
Industry:Biology; Chemistry
Toxin that forms an integral part of the cell wall of certain bacteria and is released only upon breakdown of the bacterial cell.; endotoxins do not form toxoids.
Industry:Biology; Chemistry
Transcriptional activation of a gene so that its functional product is produced.
Industry:Biology; Chemistry
Transformation of data with a logarithmic function that results in a normal distribution.
Industry:Biology; Chemistry
Tuft or a cluster, as of a plexus of capillary blood vessels or nerve fibers, e. g. capillaries of the filtration apparatus of the kidney.
Industry:Biology; Chemistry
