Shorts, safety tests

Underwriters Laboratories (UL) requires that consumer batteries pass a number of safety tests [3]. UL requires that a battery withstand a short circuit without fire or explosion. A positive temperature coefficient (PTC) device [4] is used for external short-circuit protection. The resistance of a PTC placed in series with the cell increases by orders of magnitude at high currents and resulting high temperatures. However, in the case of an internal short, e.g., if the positive tab comes lose and contacts the interior of the negative metal can, the separator could act as a fuse. That is, the impedance of the separator increases by two to three orders of magnitude due to an increase in cell temperature. 

Hradec J, Spiegelhalder B, Preussmann R. 1988. The initiator tRNA acceptance assay as a shortterm test for carcinogens. 2. Results with ten compounds selected by the International Programme on Chemical Safety for the evaluation of short-term tests for carcinogens. Carcinogenesis 9 843-846. 

By the time Phase III testing is completed, some additional preclinical safety tests must also generally be in hand. These include the three separate reproductive and developmental toxicity studies (Segments I and III in the rat, and Segment II in the rat and rabbit) and carcinogenicity studies in both rats and mice (unless the period of therapeutic usage is intended to be very short). Some assessment of genetic toxicity will also be expected. 

Careie, A., Conti, G, Conti, L. Crebelli, R. (1985) Assays in Aspergillus nidulans for the indnction of forward-mutation in haploid strain 35 and for mitotic nondisjunction, haploidization and crossing-over in diploid strain PI. In Ashby, J., de Serres, F.J., Draper, M., Ishidate, M., Jr, Margolin, B.H., Matter, B.E. Shelby, M.D., eds. Progress in Mutation Research, Volume 5, Evaluation of Short-Term Tests for Carcinogens. Report of the International Programme on Chemical Safety s Collaborative Study on in vitro assays, Amsterdam, Elsevier Science, pp. 307-312... 

Carls, N. Schiestl, R.H. (1994) Evalnation of the yeast DEL assay with 10 compounds selected by the International Program on Chemical Safety for the evalnation of short-term tests for carcinogens. Mutat. Res., 320, 293-303 Cesarone, C.F., Bolognesi, C. Santi, L. (1982) Evalnation of damage to DNA after in vivo exposnre to different classes of chemicals. Hrc/z. Toxicol, 5 (Snppl.), 355-359... 

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