Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

[Q]: Abstract: 10 coumarins used in perfumery, cosmetics and ointments, have been investigated by 2 different methods to determine their sensitizing capacity. Only 1 of the compounds, 4-methyl-esculetin, which serves as a sunscreen agent, was found to be a weak sensitizer. All other coumarins were negative. It is assumed that this dihydroxycoumarin becomes a sensitizer when it is enzymically oxidized to the corresponding orthoquinone in the skin.
[A]: Animal

[Q]: Abstract: Foreign body aspiration in children is frequently associated with unilateral emphysema or atelectasis on chest x-ray. Two cases are reported of tracheal or bilateral foreign bodies in which the original chest x-rays were read as normal, but the history was suggestive of the foreign body aspiration. Early bronchoscopy can prevent the long-term morbidity that results from unrecognized tracheobronchial foreign bodies.
[A]: Bronchoscopy

[Q]: Abstract: The prognostic value of marrow chromosome findings was examined in 242 patients with preleukemic myelodysplastic syndromes (MDS) or myeloproliferative disorders (MPD), with emphasis on the significance of single versus multiple karyotypic changes. In both groups, the results showed that patients with multiple chromosome abnormalities in a marrow clone had a very high probability of early death, from progression to leukemia or from other complications of hematopoietic dysfunction. Conversely, in patients with a hemic clone having only one karyotypic alteration (involving a single chromosome or single translocation), survival over 2 years was only slightly reduced as compared to those without chromosome abnormality. The only single karyotypic alteration perhaps associated with a markedly shortened survival was monosomy 7. These findings suggest that the conclusions of previous studies concerning the grave consequences of chromosome alterations in preleukemia largely reflect the clinical significance of clones with multiple cytogenetic changes. Prior knowledge of the karyotypic status of preleukemic patients should be helpful in evaluating current attempts to find effective treatment for these difficult disorders.
[A]:
Aged