The study of frictional properties of human skin is important for medical research, skin care products and textile exploi- tation. In order to investigate the influence of normal load and sliding speed on the friction...The study of frictional properties of human skin is important for medical research, skin care products and textile exploi- tation. In order to investigate the influence of normal load and sliding speed on the frictional properties of skin and its possible mechanism, tests were carded out on a multi-specimen friction tester. When the normal load increases from 0.1 N to 0.9 N, normal displacement and the friction coefficient of skin increase. The friction coefficient is dependent on the load, indicating that both adhesion and deformation contribute to the friction behaviour. The deformation friction was interpreted using the plough model of friction. When sliding speed increases from 0.5 mm·s^-1 to 4 mm·s^-1, the friction coefficient increases and ＂stick-slip＂ phenomena increase, indicating that hysteretic friction contributes to the friction. The hysteretic friction was in- terpreted using schematic of energy translation during the rigid spherical probe sliding on the soft skin surface, which provides an explanation for the influence of the sliding speed on the frictional characteristics of the skin.展开更多
目的探讨人体不同部位正常皮肤成纤维细胞对机械张力反应的差异。方法取色素痣切除患者自愿捐赠的背部和上臂内侧正常皮肤,应用组织块法体外培养成纤维细胞,取第5～8代细胞进行实验。将背部和上臂内侧正常成纤维细胞分别设实验组和对照...目的探讨人体不同部位正常皮肤成纤维细胞对机械张力反应的差异。方法取色素痣切除患者自愿捐赠的背部和上臂内侧正常皮肤,应用组织块法体外培养成纤维细胞,取第5～8代细胞进行实验。将背部和上臂内侧正常成纤维细胞分别设实验组和对照组,实验组细胞采用多通道细胞应力加载仪加载周期性机械张力24、36、48 h;对照组细胞正常培养。各时间点加载结束后,倒置显微镜下观察细胞形态变化;CCK-8法检测细胞增殖活性;RT-PCR法检测细胞内整合素β1、P130Ca s（p130Crk-associated substance）、TGF-β1、Ⅰ型胶原a1链（collagen type Iα1 chain,COL1A1）m RNA水平;ELISA法检测Ⅰ型胶原和TGF-β1含量。对照组于培养对应时间取细胞进行以上观察。结果实验组加载后细胞均增殖旺盛,分布密集,排列呈一定方向性。加载24 h后,实验组背部及上臂内侧细胞增殖,整合素β1、P130Cas、TGF-β1 m RNA表达水平和TGF-β1含量比较,差异均无统计学意义（P〉0.05）;加载36、48 h时,背部细胞以上检测指标均显著高于上臂内侧细胞,差异有统计学意义（P〈0.05）。实验组各时间点背部及上臂内侧细胞的COL1A1 m RNA表达水平和Ⅰ型胶原含量比较,差异均无统计学意义（P〉0.05）。对照组各时间点背部及上臂内侧细胞以上指标比较,差异均无统计学意义（P〉0.05）。结论背部和上臂内侧皮肤成纤维细胞对机械张力的反应不同,提示人体皮肤成纤维细胞的力学特征存在部位差异,可能导致不同部位增生性瘢痕的发生率不同。展开更多
基金This work was supported by the National Natural Science Foundation of China(grant No.50475164 and 50535050)by the Science Foundation of China University of Mining and Technology(grant No.2005B034).
文摘The study of frictional properties of human skin is important for medical research, skin care products and textile exploi- tation. In order to investigate the influence of normal load and sliding speed on the frictional properties of skin and its possible mechanism, tests were carded out on a multi-specimen friction tester. When the normal load increases from 0.1 N to 0.9 N, normal displacement and the friction coefficient of skin increase. The friction coefficient is dependent on the load, indicating that both adhesion and deformation contribute to the friction behaviour. The deformation friction was interpreted using the plough model of friction. When sliding speed increases from 0.5 mm·s^-1 to 4 mm·s^-1, the friction coefficient increases and ＂stick-slip＂ phenomena increase, indicating that hysteretic friction contributes to the friction. The hysteretic friction was in- terpreted using schematic of energy translation during the rigid spherical probe sliding on the soft skin surface, which provides an explanation for the influence of the sliding speed on the frictional characteristics of the skin.
文摘目的探讨人体不同部位正常皮肤成纤维细胞对机械张力反应的差异。方法取色素痣切除患者自愿捐赠的背部和上臂内侧正常皮肤,应用组织块法体外培养成纤维细胞,取第5～8代细胞进行实验。将背部和上臂内侧正常成纤维细胞分别设实验组和对照组,实验组细胞采用多通道细胞应力加载仪加载周期性机械张力24、36、48 h;对照组细胞正常培养。各时间点加载结束后,倒置显微镜下观察细胞形态变化;CCK-8法检测细胞增殖活性;RT-PCR法检测细胞内整合素β1、P130Ca s（p130Crk-associated substance）、TGF-β1、Ⅰ型胶原a1链（collagen type Iα1 chain,COL1A1）m RNA水平;ELISA法检测Ⅰ型胶原和TGF-β1含量。对照组于培养对应时间取细胞进行以上观察。结果实验组加载后细胞均增殖旺盛,分布密集,排列呈一定方向性。加载24 h后,实验组背部及上臂内侧细胞增殖,整合素β1、P130Cas、TGF-β1 m RNA表达水平和TGF-β1含量比较,差异均无统计学意义（P〉0.05）;加载36、48 h时,背部细胞以上检测指标均显著高于上臂内侧细胞,差异有统计学意义（P〈0.05）。实验组各时间点背部及上臂内侧细胞的COL1A1 m RNA表达水平和Ⅰ型胶原含量比较,差异均无统计学意义（P〉0.05）。对照组各时间点背部及上臂内侧细胞以上指标比较,差异均无统计学意义（P〉0.05）。结论背部和上臂内侧皮肤成纤维细胞对机械张力的反应不同,提示人体皮肤成纤维细胞的力学特征存在部位差异,可能导致不同部位增生性瘢痕的发生率不同。
