Analysis of cutaneous pigmentation in a sample

Abstract

ResumenAntecedentes: La mezcla de melanina, hemoglobina y carotenos definen el color cutáneo. La pigmentación constitutiva está determinada genéticamente, la facultativa se induce cuando la piel se expone al ambiente. El objetivo fue cuantificar ambas pigmentaciones en una muestra de población mexicana, y analizar su relación con el género, edad y fototipo. Métodos: Se evaluaron 259 personas durante un periodo invernal. La colorimetría cutánea se obtuvo mediante espectrometría de reflectancia difusa utilizando las coordenadas de la Comisión Internacional de Iluminación. Se registraron los valores L*a*b* y se estimó el ángulo tipológico individual (ATI°) en frente, tórax, cuello, antebrazos y glúteos. Resultados: La pigmentación facultativa difirió de la constitutiva en los parámetros L*, a*, y ATIº. En hombres, los valores facultativos de L* y ATI° fueron menores. La pigmentación constitutiva fue similar entre sexos. Los fototipos III, IV y V muestran diferencias en L*, b* y ATI°. Los valores facultativos L*, a*, ATI° y el constitutivo a* se reducen al incrementarse la edad. Conclusiones: Se cuantificaron los tonos cutáneos de una muestra de población reconociéndose los valores para la piel blanca, morena clara y morena oscura. Se presenta un marco de referencia para estudios relacionados con la pigmentación cutánea en México.

Fluorescent films based on PVDF doped with carbon dots for evaluation of UVA protection of sunscreens and fabrication of cool white LEDs

“…Sunscreen products with UVA/UVB ratio ranging from 0.21 to 0.4 present minimal UVA protection. 8 The decreased UVA protection of the CB30 and AS30+ samples is also evident considering the percentage of UVA blocking. This protection is around 50% for both cases, compared to 80% or more for the other samples.…”

“…Absorbance spectra make it possible to obtain specic parameters that indicate the level of UV and UVA protection of sunscreens. The parameters SPF, CW, SUI, UVA blocking, and UVA/UVB shown in Table 1 were calculated according to the literature 8,52 with the eqn (1)-( 5), respectively. E(l) is the relative erythema action spectrum, S(l) is the spectral irradiance (Wm À2 nm À1 ), A(l) is the spectral absorbance on the sunscreens, A is the average spectral absorbance of the sunscreens from 290 nm to 380 nm, and T(l) is the spectral transmittance of the sunscreens.…”

“…Since commercial sunscreen products are evaluated by the sun protection factor (SPF), they usually offer good protection from UVB radiation. 8 The SPF of sunscreens is calculated from the UV intensity required to produce sunburn on protected skin (using sunscreen) divided by the UV intensity required to produce sunburn on unprotected skin. This factor mainly focuses on the effects of UVB radiation on human skin and offers limited information regarding protection against UVA light.…”

Global data of unprotected skin minimal erythema dose relationship to Individual Typology Angle

“…Chardon et al 14 published the relationship between ITA° and subject MED u values with descriptors for the skin color relative to the ITA°. The ITA° has been used to characterize the skin “color” of various populations in different parts of the world 15‐18 and uses the “angle” of a vector on a plot of the skin luminance measurement versus the “b” or yellow component measurement of the skin using the CIE L a*b*coordinate system (see Figure 1). The 2010 version of ISO24444 method 5 noted the utility of ITA° as a predictive tool for determining a test subject MED u value, and recommended that laboratories develop their own chart and prediction based on their local population values.…”

Depigmentory Effects of Keishibukuryogankayokuinin in Human Epidermal Melanocytes

“…The color of the skin surface is not uniform. If the skin's internal pigment such as melanin and hemoglobin is excessively secreted, it is perceived as spots, color irregularity or dullness, and spots especially are pigmentation caused by excessive secretion of melanin in the epidermis [10]. Although the mechanism of pigmentation is not completely clear, tyrosinase has been identified as a rate-controlling enzyme [11] [12].…”