| Objective : Human skin is the body of the window. Human skin and the whole body system is the mutual influence that the changes can affect the skin, changes in the skin can cause systemic change. Therefore, the skin measuring physiological indicators caused more and more attention. It has not only reflected the state of the skin, but also on behalf of the entire situation. Research shows that when people have been mental stimulation can decrease physiological function of the skin and induce the incidence of skin diseases or exacerbate it . And the skin surface sebum content and secretion rate are influenced by the body's physiological state system more obviously.However,there are no literature reported about different developmental growth periods and different gender skin moisture content,the skin surface sebum content and secretion rate and the skin surface pH .Understand the skin stratum corneum hydration ,the skin surface sebum contents and secretion rate of the different groups in different growth stages can not only provide clinical reference, but also have guiding significance of the use and development of skin care productsMethod: Total 325 normal volunteers of Dalian City in Liaoning Province aged 3-94 (142 males, 183 females) were enrolled in the study of skin SC hydration and sebum content. Total 337 normal volunteers aged 5-94(155male,182female) were in the study of the skin surface pH . According to the growth and development stages, the subjects were divided into four groups, which include the 3-12 years old group, the 13-35 years old group, the 36-50 years old group, and the over 51 years old group. No skin care products were applied to the measured sites within 24 hours and no wash within 12 hours when the measurementswere taken.Both skin surface sebum content and SC hydration on the forehead and the forearm (flexor site) were measured with Courage Khazaka Sebumeter SM 810 and Corneometer 820, respectively. The skin surface PH is measured with PH900. Skin surface sebum content was measured immediately and one hour after washing by soap made by Colgate Sanxiao Co. Ltd in Jiangsu Province to assess the sebum recovery on the forehead. Before the measurements were taken, subjects rested for 30 min at 22-240C, with a relative humidity 45-55%. This work was performed between February and May.The measured parts are the forehead rich in sebum and the forearm (flexor site) poor in sebum, the unit is au.Result :Sebum content on forehead does not differ between males and females under 12 years of old. But sebum content is higher on the forehead of males over 13 years old than in females of the same age. Yet, sebum secretion rates are faster on forehead of females at all ages (except age 36-50) than in males. Sebum content on the forearm does not differ between males and females in all age groups. SC hydration on both forehead and forearm is the same in males as in females, except in the age 13-35 group, during which SC hydration is lower in females than in males. SC hydration on forehead in males, age 13-35, is higher than on forearm while hydration on forehead in females, age 3-12, is higher than on the forearm. SC hydration on the forehead remains the same in females at all ages. The highest contents of SC hydration are found on forehead in males aged 13-35 years old. The PH of male forehead and forearm increase with ages. The pH had little effect on female After the 13-year-old age .Females have higher PH than males .Males ' forehead and forearm have no significant difference in pH (except age5-12); The skin surface PH on forehead is significantly higher than on forearm in female (p <0.01) in the age 13-55 group.Conclusion :Sebum content, sebum secretion rates,SC hydration and Skin surface pH varies with gender, age, and body site. Males have higher serum content on forehead than in females after 13 years old. Males have the maximum SC hydration when 13-35 years old. Apart from36-50 age group, females forehead secretion of the sebum is faster than male .On gender ,females have higher PH than males。In terms of age, the pH on females' forehead and forearm increases with age increased... |
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