摘要:

SynopsisHair damage, caused by sunlight, and the possibility to protect hair against sunlight by means of cosmetic formulations was studied. For this, five UV‐filters were tested: benzophenone‐3 (UV‐A/UV‐B); benzophenone‐4 (UV‐A/UV‐B); phenylbenzimidazole sulfonic acid (UV‐B); butylmethoxydibenzoylmethane (UV‐A); octyl dimethyl PABA (UV‐B). The stability of the UV‐filters was tested as pure substances as well as in two cosmetic formulations: a setting lotion and a shine spray. The degree of decolouration and stress strain behaviour were determined. The benzophenones had the best protection ability both on colour and on morphology. Stability data and UV

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1993.tb00074.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryMeasurements of skin mechanics are required to understand better cracking and flaking of the epidermis and loss of ‘elasticity’with age in the dermis. Improvements in torsional testing are described here. The resulting data was fitted to algebraic models, the parameters of which can serve both as a concise description of the responses and as a means of relating them to skin structure and physiology. This investigation looks into the suitability of seven such algebraic models. Five of the models examined here appear to be new.Using the commercially available Dia‐Stron DTM Torque Meter with our own software, model parameters were studied as indicators of the effects of age and sex in 41 people, and of skin moisturizing treatments in a further 10 people. The two models in the literature were both found to be substantially less accurate and sensitive representations of experimental data than one of the new models proposed here based on the Weibull distribution. This ‘WB model’was consistently the one best able to distinguish differences and detect changes which were statistically significant. The WB model appears to be the most powerful and efficient available. Use of this model makes it possible to demonstratein vivoa statistically significant mechanical difference between male and pre‐menopausal female skin using only one parameter (p= 0.0163, with 18 males and 19 females) and to demonstrate a statistically significant mechanical difference between successive decades of age in female skin using only one parameter (p= 0.0124,n= 24). The two parameters of the model most sensitive to skin structure, function and treatment have been combined to form the axes of a ‘Skin condition chart’. Any person can be located on this chart at a point indicating their overall skin condition in mechanical terms and any changes in that condition can be clearly demonstrated by movement

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1993.tb00075.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryMagnetic resonance imaging is a non‐invasive, non‐destructive and chemically specific imaging method widely used in medicine to reveal information about both tissue structure and function. It can measure water in tissue, but it has been difficult to achieve the necessary sensitivity and resolution when applying it to studies of the dry, thin stratum corneum. In this paper the use of magnetic resonance imaging to image the outer layers of the skin with a resolution of 0.06 mm is reported. Configuring the magnetic resonance imaging method in this way has made it possible for the first time to actually ‘see’directly the moisturization in the stratum corneum. It is no longer necessary to rely upon methods which can only show side‐effects of moisturization, such as changes in the appearance of the skin cells. As magnetic resonance imaging is harmless, it can be used repeatedly on the same skin and so produce a series of stills, or a time‐lapse video, clearly showing the actual process of moisturization and related phenomena. The behaviour of skin has been observed during both hydration and dehydration; the two processes follow different time courses. Two layers have been observed in the stratum corneum, which appear to be different when the skin is hydrated.For the first time the actual surface of normal skin has been revealed on magnetic reson

ISSN:0142-5463    

DOI:10.1111/j.1467-2494.1993.tb00076.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY