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BooBop · 06-13-2002, 12:42 PM

Cosmetic Aspects: Likes and dislikes differ, and personal taste can always change. But even so there always appears to be a happy medium of timeless elegance. With respect to tanning, the desired look falls somewhere between the pasty white facdes of yesteryear and the "overdone" tan which leaves the skin dry and leathery. Most preferable is a fresh-looking summer tan. Everything should be done in moderation.

Light Protection: nature did not provide us with skin pigmentation as built-in cosmetic convenience. Instead, pigmentation as the callosity (thickening of the crneum) and as photoprotections(stabilization of the germ-plasm) acts as a screen to protect the body against too much sun.

Melanin Sunthesis through UVB: Deep down in the skin are special cells called melanocytes. Once these are stimulated with UV light, they will utilize the amino acid tyrosine which they have stored up to produce the pigment melanin. Because these substances only absorb ultraviolet light of approximately 320nm, UVB rays must be present in order to achieve melanin production.

UVA Melanogenesis: UVA can also formulate melanin but only when there exists enough photsensitizing material in the skin to bring about a UVB-type reaction. However, this requires a very high radiation intensity for a long period of time. On the other hand, UVB can induce the same desird melanin production utilizing very low levels of radiation with more frequent exposures (21). In addition, UVB will not penetrate as deeply into the lower layer of connective tissue in the skin.

Melanin protects DNA: The pale pink colored melanin granules fromed in the melanocytes will travel upward toward the horny layer of croneum. They are stroed around the nuclei of the keratin cells there. In this manner, the pigment protects the UVB sensitive DNA located inside the nuclei without impeding the other positive effects of ultraviolet light. The energy absorbed by the pigment granules will be returned to the cell in form of heat.

Pigment Darkening by UVA: In the preliminary stages of meleanin production, very little protection is offered to the skin. In order to render the pigmentation process effective, the melanin granules must darken (oxidize). this requires a higher dosage of long wave UVA.

Antioxidats: The dosage of UVA must be sufficiently high in order to provide enough energy to initiate the oxidation process. It must be remembered that UVA rays do not carry as much energy as UVB ray. Longwave radition is essential becasue high does of shortwave rays will activate substances in the body which will hinder the tannin process such as asorbic acid and cystenine. these anti-oxidant not only inhibit oxidation of pigment but can even revers the proess.

Thus, UVB serves to synthesize the pigment granules while UVA ensures their oxidation. Together they form a light protection mechanism.

Oh Lord, someone stop me before I copy the whole book here.

Sunbathing Today 2. revised Freidrich Wolff

_________________
Barkin with the Big Dog since April 2002
Mitzi

[ This Message was edited by: Mitzi on 2002-06-13 13:10 ][ This Message was edited by: Chippp on 2002-06-13 14:49 ]

06-13-2002, 12:42 PM	#1 (permalink)
BooBop I love Derf!! Join Date: Apr 5 2001 Posts: 9,496 Rep Power: 13	Cosmetic Aspects: Likes and dislikes differ, and personal taste can always change. But even so there always appears to be a happy medium of timeless elegance. With respect to tanning, the desired look falls somewhere between the pasty white facdes of yesteryear and the "overdone" tan which leaves the skin dry and leathery. Most preferable is a fresh-looking summer tan. Everything should be done in moderation. Light Protection: nature did not provide us with skin pigmentation as built-in cosmetic convenience. Instead, pigmentation as the callosity (thickening of the crneum) and as photoprotections(stabilization of the germ-plasm) acts as a screen to protect the body against too much sun. Melanin Sunthesis through UVB: Deep down in the skin are special cells called melanocytes. Once these are stimulated with UV light, they will utilize the amino acid tyrosine which they have stored up to produce the pigment melanin. Because these substances only absorb ultraviolet light of approximately 320nm, UVB rays must be present in order to achieve melanin production. UVA Melanogenesis: UVA can also formulate melanin but only when there exists enough photsensitizing material in the skin to bring about a UVB-type reaction. However, this requires a very high radiation intensity for a long period of time. On the other hand, UVB can induce the same desird melanin production utilizing very low levels of radiation with more frequent exposures (21). In addition, UVB will not penetrate as deeply into the lower layer of connective tissue in the skin. Melanin protects DNA: The pale pink colored melanin granules fromed in the melanocytes will travel upward toward the horny layer of croneum. They are stroed around the nuclei of the keratin cells there. In this manner, the pigment protects the UVB sensitive DNA located inside the nuclei without impeding the other positive effects of ultraviolet light. The energy absorbed by the pigment granules will be returned to the cell in form of heat. Pigment Darkening by UVA: In the preliminary stages of meleanin production, very little protection is offered to the skin. In order to render the pigmentation process effective, the melanin granules must darken (oxidize). this requires a higher dosage of long wave UVA. Antioxidats: The dosage of UVA must be sufficiently high in order to provide enough energy to initiate the oxidation process. It must be remembered that UVA rays do not carry as much energy as UVB ray. Longwave radition is essential becasue high does of shortwave rays will activate substances in the body which will hinder the tannin process such as asorbic acid and cystenine. these anti-oxidant not only inhibit oxidation of pigment but can even revers the proess. Thus, UVB serves to synthesize the pigment granules while UVA ensures their oxidation. Together they form a light protection mechanism. Oh Lord, someone stop me before I copy the whole book here. Sunbathing Today 2. revised Freidrich Wolff _________________ Barkin with the Big Dog since April 2002 Mitzi [ This Message was edited by: Mitzi on 2002-06-13 13:10 ][ This Message was edited by: Chippp on 2002-06-13 14:49 ]