Visible skin condition and perception of human facial appearance

Evolutionary psychology suggests that certain human beauty standards have evolved to provide reliable cues of fertility and health. Hence, preferences for some physical characteristics of the face and body are thought to reflect adaptations for the promotion of mate choice. Studies that have investigated facial attractiveness have concentrated mainly on features such as symmetry, averageness and sex‐typical traits, which are developed under the influence of sex steroids. Few studies, however, have addressed the effect of human skin condition on perception of facial appearance in this context, and possible implications for sexual selection. There is now accumulating evidence that skin pigmentation and skin surface topography cues, particularly in women, have a significant influence on attractiveness judgements, as they seem primarily to signal aspects of age and health. This article (i) reviews briefly some of the main determinants of visible skin condition, (ii) presents recent evidence on its signalling value in face perception and (iii) suggests areas for future research with reference to an evolutionary psychology framework.     

Differences in visual perception of age and attractiveness of female facial and body skin

Perception of age and health is critical in the judgement of attractiveness. The few studies conducted on the significance of apparent skin condition on human physical appearance have studied faces alone or isolated fields of images facial skin. Little is known about whether perception of the face matches that of other body parts or if body skin affects overall age and attractiveness perception when presented in combination with facial skin. We hypothesized that independent presentation of female faces, chests and arms (including hands) – cropped from a full face and upper body image – would result in significant differences in perception of age and attractiveness compared to the corresponding composite. Furthermore, we sought to investigate whether relatively young and attractive looking skin on selected, individual parts of the body affects overall perception. Digital photographs of 52 women aged 45–65 years were collected and processed to yield four derivative sets of images: One set showed the composite of all features, i.e. the face, the chest and the arms, whereas the other three were cropped carefully to show each part of the upper body described above independently. A total of 240 participants judged these faces for perceived age and attractiveness. Our results showed significant differences in perception with the chest and the arms being judged significantly younger than the face or composite image of the same women. Moreover, arms and chest images were perceived as more attractive than face and composite images. Finally, regression analysis indicated that differences between the perceived and chronological values of overall age perception could be predicted by age perception of the face and arms. These results continue to support the significance of facial age perception in assessment of a woman’s age, but highlight that body skin also plays a role in overall age impression.     

Influence of skin cleansing preparation acidity on skin surface properties

Two long-term trials were conducted each over eight weeks to compare the effect of the regular application of skin cleansing preparations of pH 5.5 and pH 8.5 and pH 5.5 and pH 7.0 respectively on the surface pH, roughness and transepidermal water loss (TEWL) of normal human forehead and forearm skin. Both trials were based on a cross-over design: five healthy volunteers started with a pH 5.5 preparation and switched to the other after four weeks, five additional volunteers used the preparations in the opposite order. While the skin surface pH was markedly lower in those individuals using the pH 5.5 preparation at each examination, as compared to those using the pH 8.5 or pH 7.0 preparation, no such difference could be established with respect to skin roughness and TEWL. Hence the skin irritancy of a cleansing preparation does not seem to be linked to its pH within the pH ranges tested.     

Qualitative assessment of tear dynamics with fluorescein profilometry

Purpose

To describe a new methodology for tear-film dynamics assessment by observing fluorescein decay rate over time and to understand the relationship between the newly defined tear fluorescein washout rate (TFWR) and other measures of the tear film behaviour.

Skin smoothing effects of Dead Sea minerals: comparative profilometric evaluation of skin surface

The skin smoothing effects of three different liquid gels were compared on 20 mature women. Treatment applications were performed twice a day over a period of 4 weeks, and the skin roughness parameter (Rz) of all test participants was determined at the beginning and at the end of the study using a computer-aided laser profilometry, in accordance with DIN 4768 ff. At the end of the application period, the liquid gel with 1% of a Dead Sea mineral solution had an average skin roughness parameter reduction of 40.7%. The liquid gel without mineral additives showed an average reduction in skin roughness of 27.8%. The control gel without anti-wrinkle agents or the additives showed an average reduction of only 10.4%.     

Surface coverage with single vs. multiple gaze surface topography to fit scleral lenses

Objectives

To determine surface coverage of measurements using the sMap3D^® corneo-scleral topographer in patients presenting for scleral lens fitting.

微波辅助提取蚕豆种皮中总黄酮的条件优化

以蚕豆种皮总黄酮产率为指标,对提取过程中的液料比、微波功率、提取时间采用响应面法优化。结果表明,最佳提取条件为液料比27∶1(mL/g)、微波功率460W、提取时间50s,此提取条件下,蚕豆种皮总黄酮产率达0.5469%。      

Image analysis as a tool for measuring biological phenomena of the skin

In an industry very much concerned with image it is not surprising to find that Image Analysers are beginning to fulfil the potential that a few groups recognized some time ago. This presentation will outline briefly the principles of image analysis and demonstrate how these can be put to use in measurement. Skin will be referenced as the example almost throughout this text, though it is important to remember that there are other applications which may interest cosmetic chemists; in the field of particulates and emulsions for example, and generally in production quality control. Finally, since the technology is often very easy to use, potential dangers in its misuse will also be pointed out where necessary.     

响应面法优化鳕鱼皮酸溶性胶原蛋白的提取工艺

为了提高鳕鱼皮中酸溶性胶原蛋白的提取率,选取提取液浓度、提取时间和料液比为影响因素,以胶原蛋白提取率为响应值,在单因素实验基础上,根据中心组合（Box-Behnken）实验设计原理,对鳕鱼皮酸溶性胶原蛋白的提取工艺进行优化。结果表明酸法提取胶原蛋白最佳工艺条件:醋酸浓度为0.47 mol/L、料液比为1∶33、提取时间为90.2 h。在此条件下提取所得酸溶性胶原蛋白提取率的理论值为37.92%,实验验证值为37.36%。相对误差为1.49%,说明采用响应面法优化得到的酸法提取鳕鱼皮胶原蛋白的工艺参数准确可靠,为鳕鱼皮酸溶性胶原蛋白的提取提供了一定的技术参考。      

响应面法优化罗非鱼皮酶法脱脂工艺

以罗非鱼鱼皮为原料,在单因素实验基础上,选取脱脂温度、脱脂时间、加酶量为自变量,罗非鱼皮脱脂率为响应值,利用Box-Benhnken中心组合设计和响应面分析法,对罗非鱼皮酶法脱脂的工艺条件进行优化。结果表明:脂肪酶对罗非鱼皮脱脂的最优工艺条件为pH9、加酶量0.5%、脱脂温度39℃、脱脂时间56 min,在此条件下鱼皮脱脂率为63.71%。      

Scleral topography analysed by optical coherence tomography

Purpose

A detailed evaluation of the corneo-scleral-profile (CSP) is of particular relevance in soft and scleral lenses fitting. The aim of this study was to use optical coherence tomography (OCT) to analyse the profile of the limbal sclera and to evaluate the relationship between central corneal radii, corneal eccentricity and scleral radii.

响应面法优化酶解罗非鱼皮制备抗氧化肽的工艺研究

采用响应面分析法对酶法水解罗非鱼皮制备抗氧化肽的工艺条件进行优化。以水解度、DPPH自由基与OH自由基半抑制浓度(IC50)、还原力为评价指标,分析比较了商业蛋白酶中的酸性蛋白酶、中性蛋白酶、碱性蛋白酶、胰蛋白酶、菠萝蛋白酶及木瓜蛋白酶对罗非鱼皮的水解效果及其产物的抗氧化活性,筛选出碱性蛋白酶为最佳水解用酶,并利用响应面分析法对罗非鱼皮酶解条件予以了优化,最终确立的最佳酶解工艺为:p H10.00、反应时间4 h、温度40℃、料液比0.38 g/m L,在此条件下产物的还原力为1.054,与模型预测值相吻合,表明了响应面法的有效性。      

Precise measurement of scleral radius using anterior eye profilometry

Purpose

To develop a new and precise methodology to measure the scleral radius based on anterior eye surface.

Study of surfactant-skin interactions by skin impedance measurements

The stratum corneum (SC) plays a very critical physiological role as skin barrier in regulating water loss through the skin and protects the body from a wide range of physical and chemical exogenous insults. Surfactant-containing formulations can induce skin damage and irritation owing to surfactant absorption and penetration. It is generally accepted that reduction in skin barrier properties occurs only after surfactants have penetrated/permeated into the skin barrier. To mitigate the harshness of surfactant-based cleansing products, penetration/permeation of surfactants should be reduced. Skin impedance measurements have been taken in vitro on porcine skin using vertical Franz diffusion cells to investigate the impact of surfactants, temperature and pH on skin barrier integrity. These skin impedance results demonstrate excellent correlation with other published methods for assessing skin damage and irritation from different surfactant chemistry, concentration, pH, time of exposure and temperature. This study demonstrates that skin impedance can be utilized as a routine approach to screen surfactant-containing formulations for their propensity to compromise the skin barrier and hence likely lead to skin irritation.     

石膏板护面纸搓皮纸病的处理

随着科学技术的发展,纸面石膏板在工业、农业、建筑业得到了广泛的应用,对石膏板护面纸的质量要求也越来越高。石膏板护面纸的表面搓皮主要是由其表面强度低引起的。     

Absorption of materials by or through the living skin

The skin comes into contact with a large range of materials either deliberately or inadvertently. It should be possible to predict the exact transport rates of these materials through the skin as a function of the physicochemical properties of the different compounds. With this sort of knowledge it is possible to predict the exact disposition of compounds and use this in the formulation of new products both in the pharmaceutical and cosmetic field. The information will also be useful from the standpoint of skin toxicology and environmental health. In order to be able to predict this complex process it is necessary to split the overall transport into different component parts. This article will identify these components and provide illustrations. The major areas discussed will be barrier function of the skin, the release properties of different topical formulations and how these may be monitored. Novel means of enhancing the penetration of drugs will be discussed and how some additives that are incorporated into formulations will perhaps alter the barrier function of skin. A mathematical model describing skin penetration has been developed and its use in predicting blood levels will be described. This model has been tested both in animal experiments and in limited human studies and its relevance to these situations will be highlighted.
Absorption cutanée et transcutanée in vivo