352 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table III Effectiveness of Various Reagents on Hair Straightening Reagents pH Reduction in Lanthionine Degree hair cysteine formed of hair (%) (%) straightening NaOH (1 N) 14.0 35 24 Complete/permanent NaOH (0. t N) 13.0 30 17 Partial/temporary DTT (0.8 M) 3.5 90 0 None LiC1 (40%) 7.0 3 0 Complete/permanent THP (1 M) 8.5 45 0 Complete/permanent TGA ( 1.2 M) 9.6 54 0 Partial/temporary Urea (50%) 7.0 -- 0 None Resorcinol (40%) 7.0 -- 0 Complete/permanent Boiling water* 5 0 Complete/permanent * Under tension. A MODEL FOR HAIR STRAIGHTENING Based on our observations, it appears that the first step in the process of hair straight- ening is the uncoiling of the hair curl through the action of radial swelling of the fiber. But it is the subsequent supercontraction of the fiber that determines the success of permanent straightening. If the supercontraction is irreversible, and if the supercon- traction is substantial (5% or more), permanent straightening can indeed be achieved. The kinetics of supercontraction is also important in determining the outcome of hair straightening. Permanent hair straightening can be achieved rapidly if fiber supercon- traction is fast. These observations suggest that the effect of the fiber supercontraction is essentially to "lock" the fiber in the straight configuration, preventing it from reverting to its native curly configuration. On the molecular level, fiber supercontrac- tion is the result of changes in the secondary structure, involving the so-called alpha- beta phase transition in the organized phase of the keratin (9-11). It is believed that it is the irreversible consequence of these molecular conformational changes that leads to permanent hair straightening. Thus, the c.leavage of cystine and the formation of lan- thionine are merely by-products rather than prime requirements of permanent hair straightening. REFERENCES (1) M. J. Horn, B. D. Jones, and S. J. Ringel, J. Bio. Chem., 138, 141 (1941). (2) R. S. Asquith and P. Carthew, Biochim. Biophys. Acta, 278, 8 (1972). (3) J. M. Swan, Nature, 179, 965 (1957). (4) J. Chao, E. Newsome, I. M. Wainwright, and R. A. Mathews,J. Soc. Cosmet. ½hem., 30, 401 (1979). (5) K. Baird, Text. Res. J., 33, 866 (1963). (6) M. Cednes, Text. Res. J., 52, T25t (1961). (7) F. J. Worthmann and H. Heutz, J. Appl. Polym. Sci., 48, 137 (1993). (8) M. Feughelman, A. R. Haly, and W. Snaith, Text. Res. J., 32, 913 (1962). (9) W. T. Astbury and H. T. Wood, Phil. Trans Roy. Soc., A232, 333 (1933). (t0) P. Alexander, Wool: Its Chemistry and Physics (Chapman & Hall, London, 1954), pp. 76, 374. (lt) W. G. Crewther and L. M. Dowling, Text. Res. J., 29, 541 (1951).

j. Soc. Cosmet. Chem., 45, 353-354 (November/December 1994) AUTHOR INDEX Alhaique, F., see Memoli, A., 167 Amro, B. I. H., A quantitative study of dyeing with lawsone, 159 Aronson, M.P., see Murahata, R. I., 239 Bai!!et, A., see Laugel, C., 337 Baites, B., see Schrader, A., 43 Barry, E. F., see Michalakis, G. M., 193 Bimczok, R., A multicenter comparison of different test methods for the assessment of the efficacy of skin care products with 368 human volunteers, 1 Breda, B., see Guesnet, J., 65 Cae!!es, J., see Seguer, J., 53 Carton, I., see Guesnet, J., 65 Chaminade, P., see Laugel, C., 337 Chang, A., see Feng, Y., 299 Close, J., The concept of sensory quality, 95 Dersigny, D., see Guesnet, J., 65 DiFruscia, R., see LaFreniere, K., 109 el Gainreal, $., see Pagnoni, A., 221 Epps, J., see Wong, M., 347 Evans, T. A., The kinetics of hair reduction, 279 Feng, Y., Kinetics and mechanism of indo-aniline dye formation in aqueous peroxide solution, 299 Ferrier, D., see Laugel, C., 337 Geise, R. J., Determination of diazolidinyl urea in cosmetic formulations by capillary electrophoresis, 173 Goffin, V., see Pi6rard,G. E., 269 Guarneri, M., see Scalia, S., 35 Gu6nin, E. P., Effect of Salicylic acid encapsulation by phospholipid vesicles on transport through an inert membrane, 229 Guesnet, J., An optimization method for cosmetic formulation: A new practical approach, 65 Hami, A., see Nanavati, S., 135 H'6cker, H., see Ito, H., 183 Hope, J., see Rawlings, A. V., 203 Iannie!!o, R. M., see Geise, R. J., 173 Imbert, D., Influence of liposomal encapsulation on the penetration of retinoic acid through human skin in vitro, 119 Infante, M•'R., see Seguer, J., 53 Ito, H., Damage of hair fibers as evaluated by an electrical capacitance technique, 183 Jachowicz, J., Fingerprinting of cosmetic formulations by dynamic electrokinetic and permeability analysis I. Shampoos, 309 Jakupovic, J., see Schrader, A., 43 James, K. C., see Amro, B. I. H., 159 Kasting, G. B., see Imbert, D., 119 Kligman, A.M., see Pagnoni, A., 221 Kligman, L. H., The Protective effect of a broad-spectrum sunscreen against chronic UVA radiation in haitiess mice: A histologic and ultrastructural assessment, 21 Kure, N., see Wortmann, F.-J., 149 LaFreniere, K., A two-stage method for the in vivo replication of human skin: Method refinement and application, 109 Laugel, C., Analytical investigation of W/O/W emulsion stability using dihydralazine as breakdown indicator, 337 Lee, B. L., see Pena, L. E., 77 Machnicki, N. I., see Geise, R. J., 173 Manresa, A., see Seguer, J., 53 Mayo, A., see Rawlings, A. V., 203 Memoli, A., Liposomes in cosmetics. II. Entrapment of a hydrophilic probe, 167 Menegatti, E., see Scalia, S., 35 Michalakis, G. M., Determination of imidurea in cosmetic products by capillary zone electrophoresis and micellar electrokinetic chromatography, 193 Molinero, J., see Seguer, J., 53 Morat, J. L., see Guesnet, J., 65 Murahata, R. I., The relationship between solution pH and clinical irritancy for carboxylic acid-based personal washing products, 239 353