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Results for “Hair Color”

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PubMed2004

Hair color changes and protein damage caused by ultraviolet radiation.

Ultraviolet and visible radiations are known to damage hair. However, quantitative data relating damage to hair type, proteins and color to the radiation wavelength are missing. We studied the effect of UV plus visible, UVA plus visible, visible mercury-vapor lamp radiation and sunlight on (blended) virgin dark-brown, blond and red hair and (one head) virgin black and curly dark-brown hair. All hair types showed a substantial increase in protein loss in water after lamp and sun irradiation. The damaging effect of UVB was about 2-5 times higher than that of UVA plus visible radiation, depending on the hair type. Significant color changes were also observed in every hair type, after lamp and sun irradiation, being more pronounced for the light colored hairs. The luminosity difference parameter was the major contributor to the hair color changes, but significant changes in the red-green and yellow-blue parameters of every hair were observed. In this case, the damaging effect is ascribable mainly to UVA radiation. No significant changes in the mechanical properties or topography were observed in any case. We discuss these results in terms of hair type and composition and melanin types.

Color↗
PubMed2000

Comparison of narrow-band reflectance spectroscopy and tristimulus colorimetry for measurements of skin and hair color in persons of different biological ancestry.

We have used two modern computerized handheld reflectometers, the Photovolt ColorWalk colorimeter (a tristimulus colorimeter; Photovolt, UMM Electronics, Indianapolis, IN) and the DermaSpectrometer (a specialized narrow-band reflectometer; Cortex Technology, Hadsund, Denmark), to compare two methods for the objective determination of skin and hair color. These instruments both determine color by measuring the intensity of reflected light of particular wavelengths. The Photovolt ColorWalk instrument does so by shining a white light and sensing the intensity of the reflected light with a linear photodiode array. The ColorWalk results can then be expressed in terms of several standard color systems, most importantly, the Commission International d'Eclairage (CIE) Lab system, in which any color can be described by three values: L*, the lightness; a*, the amount of green or red; and b*, the amount of yellow or blue. Instead of a white light and photodiodes, the DermaSpectrometer uses two light-emitting diodes (LEDs), one green and one red, to illuminate a surface, and then it records the intensity of the reflected light. The results of these readings are expressed in terms of erythema (E) and melanin (M) indices. We measured the unexposed skin of the inner upper arm, the exposed skin of the forehead, and the hair, of 80 persons using these two instruments. Since it is important for the application of these measures in anthropology that we understand their relationship across a number of different pigmentation levels, we sampled persons from several different groups, namely, European Americans (n = 55), African Americans (n = 9), South Asians (n = 7), and East Asians (n = 9). In these subjects, there is a very high correlation between L* and the M index for the inner arm (R(2) = 0.928, P < 0.001), the forehead (R(2) = 0.822, P < 0.001), and the hair (R(2) = 0.827, P < 0.001). The relationship between a* and the E index is complex and dependent on the pigmentation level. We conclude that while both types of instruments provide accurate estimates of pigment level in skin and hair, measurements using narrow-band instruments may be less affected by the greater redness of certain body sites due to increased vascularization.

Adult↗
PubMedDate not supplied

Gallbladder motility in healthy volunteers: effects of age, gender, body mass index, and hair color.

BACKGROUND/AIMS: Ultrasonographic determination of gallbladder motility is sparsely performed in clinical practice as the examination is considered to be time consuming and there is uncertainty about a number of parameters possibly influencing the results. The aims of this study were a) to establish normal values for a simple ultrasonographic test and b) to evaluate the influence of different parameters on gallbladder motility. METHODOLOGY: In 62 systematically age- and sex-matched healthy volunteers, ultrasonographic measurements of gallbladder volume (ellipsoid method, planimetry and sum-of-cylinders method) were performed fasting and 5, 10, 20, 30, 40, 50, 60, 70 and up to 75 min after stimulation with a standardized high-caloric liquid meal. RESULTS: Using the ellipsoid method, gallbladder fasting volume (V0) reached a mean value (+/- SD) of 24.6 +/- 10.0 mL with an ejection fraction of 65.9 +/- 19.1%. Age, gender and hair color did not influence parameters of gallbladder contraction. Body mass index showed a weak correlation with V0 but not with ejection fraction. There was a highly significant correlation between the ellipsoid method and longitudinal planimetry and the sum-of-cylinders method, respectively. CONCLUSIONS: Ultrasonographic measurement of gallbladder motility in healthy volunteers shows a very wide scattering of normal values. In the interpretation of gallbladder emptying, age, gender and body mass index do not have to be considered. Determination of gallbladder motility may be performed by a rather simple approach with oral stimulation and ellipsoid method or longitudinal planimetry as easily applicable ultrasonographic measurements.

Adolescent↗
PubMed1989

Host-guest complexation in capillary isotachophoresis. II. Determination of aminophenol and diaminobenzene isomers in permanent hair colorants by using capillary isotachophoresis.

The separation of 2-, 3- and 4-aminophenol and 1,2-, 1,3- and 1,4-diaminobenzene is studied by using capillary isotachophoresis. In order to obtain complete resolution of the six cations beta-cyclodextrin was used. The analytical method was used for the determination of aminophenol and diaminobenzene isomers in permanent hair colorant creams.

Aminophenols↗
PubMed1997

[Hair colorants].

The properties, mode of action and its duration of the preparations used for hair dyeing are described, together with their chemical components, and also preparations of herbal origin. The chemical reactions are described in detail which lead the development of a color polymer occurring during hair dyeing. The studies are presented which are used for toxicological assessment of the raw materials which are the components of the colorants, and the list is included of hair colorants permitted for use in Poland.

Animals↗