2010 TRI/PRINCETON CONFERENCE 201 Table V Peak Intensity Values and Pertinent Peak Ratios for Bleached Dark Brown and Piedmont Hair Exposed to UV Radiation ITrp IKyn I509 ITrp/IKyn I509/IKyn Dark brown- bleached 33,150 ± 2,192 237,000 ± 5,657 130,500± 4950 0.140 ± 0.006 0.551 ± 0.034 Dark brown- bleached-UV 24,550 ± 1,344 163,500 ± 707 99,650 ± 3323 0.150 ± 0.008 0.610 ± 0.023 Piedmont- bleached 68,950 ± 4,031 3,075,000 ± 120,208 1,480,000 ± 56,568 0.022 ± 0.000 0.482 ± 0.037 Piedmont- bleached-UV 38,150 ± 1,061 2,170,000 ± 14,142 999,500 ± 99,702 0.018 ± 0.000 0.461 ± 0.049 Data are provided for the unexposed and exposed regions of the hair tress. It may be more informative to examine the differences between photo-exposed and unex- posed regions of the hair tress. These data are provided in Table VI and illustrate the effects of oxidizing melanin in dark brown hair and removing the yellow pigment in Piedmont hair. The difference in ITrp between the unexposed and exposed regions of the tress increase in photo-irradiated hair that is fi rst subjected to bleaching treatment. The same observa- tion was made for IKyn and I509. In relation to the fl uorophores monitored, hair that has undergone bleaching is more susceptible to photo-degradation than the same hair that has not been chemically treated. This is true for both dark brown and Piedmont hair. CONCLUSIONS We utilized steady-state spectrofl uorescence as an analytical tool to monitor the health of human hair fi bers. Hair was subjected to routine consumer stresses such as bleaching, straightening (chemical relaxers), hot thermal irons, and solar radiation. Fluorescence excitation-emission matrices were generated for hair providing a spectroscopic map of all its fl uorophores. Two different hair types, Piedmont and dark brown, were utilized to monitor the effects of melanin as a protecting agent and its infl uence on the fl uorescence Table IV Peak Intensity Values and Pertinent Peak Ratios for Dark Brown and Piedmont Hair Exposed to UV Radiation ITrp IKyn I509 ITrp/IKyn I509/IKyn Dark brown 31,200 ± 2,121 86,150 ± 495 26,500± 0 0.362 ± 0.022 0.308 ± 0.001 Dark brown-UV 25,850 ± 1,061 55,650 ± 1,202 15,800 ± 566 0.465 ± 0.029 0.284 ± 0.002 Piedmont 37,900 ± 283 1,825,000 ± 91,923 1,300,000 ± 28,284 0.021 ± 0.001 0.713 ± 0.020 Piedmont-UV 29,250 ± 5728 1,440,000 ± 42,426 659,500 ± 33,234 0.020 ± 0.003 0.458 ± 0.010 Data are provided for the unexposed and exposed regions of the hair tress.

JOURNAL OF COSMETIC SCIENCE 202 behavior of hair when subjected to physical and chemical stresses. For example, bleaching of both hair types resulted in an increase in the fl uorescence signal of Trp, which could be attributed to its greater absorption and subsequent emission in the absence of other chromophores. Hair straightening was found to damage Trp and, ultimately, the kynure- nines. Thermal exposure of hair results in a dark yellow discoloration, evident in Pied- mont hair, which correlates with an increase in the fl uorescence intensity of the kynurenine bands. On the other hand, upon extended photo-irradiation, Piedmont hair was found to lose its natural yellow pigmentation—concurrent with a decrease in the intensity of kynurenine fl uorescence. REFERENCES (1) T. Inoue, M. Ito, and K. Kizawa, Labile proteins accumulated in damaged hair upon permanent waving and bleaching treatments, J. Cosmet. Sci., 53, 337–344 (2002). (2) M. Wong, G. Wis-Surel, and J. Epps, Mechanism of hair straightening, J. Soc. Cosmet. Chem., 45, 347–352 (1994). (3) H. Zahn, S. Hilterhaus, and A. Strüβmann, Bleaching and permanent waving aspects of hair research, J. Soc. Cosmet. Chem., 37, 159–175 (1986). (4) Y. Masukawa, H. Tsujimura, H. Tanamachi, H. Narita, and G. Imokawa, Damage to human hair caused by repeated bleaching combined with daily weathering during daily life activities, Exog. Dermatol., 3, 273–281 (2004). (5) V. Signori, Review of the current understanding of the effect of ultraviolet and visible radiation on hair structure and options for photoprotection, J. Cosmet. Sci., 55, 95–113 (2004). (6) A. C. S. Nogueira, L. E. Dicelio, and I. Joekes, About photo-damage of human hair, Photochem. Photobiol. Sci., 5, 165–169 (2006). (7) R. McMullen and J. Jachowicz, Thermal degradation of hair. I. Effect of curling irons, J. Cosmet. Sci., 49, 223–244 (1998). (8) M. Gamez-Garcia, The cracking of human hair cuticles by cyclical thermal stresses, J. Cosmet. Sci., 49, 141–153 (1998). (9) S. B. Ruetsch and Y. K. Kamath, Effects of thermal treatments with a curling iron on hair fi ber, J. Cosmet. Sci., 55, 13–27 (2004). (10) C. M. Pande and J. Jachowicz, Hair photodamage—Measurement and prevention, J. Soc. Cosmet. Chem., 44, 109–122 (1993). (11) S. Daly, R. Bianchini, T. Polefka, L. Jumbelic, and J. Jachowicz, Fluorescence and coloration of grey hair, Int. J. Cosmet. Sci., 31, 347–359 (2009). (12) J. Jachowicz and R. McMullen, Factors affecting tryptophan fl uorescence in hair, J. Cosmet. Sci., (submit- ted) (2011). (13) J. J. Prompers, C. W. Hilbers, and H. A. M. Pepermans, Tryptophan mediated photoreduction of disulphide bond causes unusual fl uorescence behavior of Fusarium Solani pisi cutinase, FEBS Lett., 45, 409–416 (1999). (14) K. R. Millington, Photoyellowing of wool. Part 1: Factors affecting photoyellowing and experimental techniques, Color. Technol., 122, 169–186 (2006). Table VI Peak Intensity Value Differences Between Unexposed and Exposed (unexposed - exposed) Region of the Tress ITrp IKyn I509 Dark brown 5,350 ± 1,061 30,500 ± 1,697 10,700 ± 566 Piedmont 8,650 ± 6,010 385,000 ± 134,350 640,500 ± 61,518 Dark Brown-bleached 8,600 ± 849 73,500 ± 4,950 30,850 ± 1,626 Piedmont-bleached 30,800 ± 2,970 905,000 ± 106,066 480,500 ± 43,134