Application of a tensile-strength test method to the evaluation of hydrating hair products

The usual methods applied to studying the hydration state of hair (e.g. gravimetry, microscopy, evaporimetry) are mostly concerned with a limited area of the fibre. Consequently, the results obtained do not reflect the variability of the physicochemical properties of the whole fibre. Moreover, there are not many experimental methods to evaluate the hydrating power of hair care products in the literature. This study proposes a new method to measure the hydration state of treated or untreated hair by using a tensile strength test. A graphic analysis of tensile strength variation as a function of relative humidity after hair treatment allows the calculation of three hydration indexes: protection index, instant hydration index and permanent hydration index. This technique can give useful information on the behaviour of hair versus relative humidity and on the different hydrating mechanisms exhibited by hair care products.     

The role of primary alkanolamines in cosmetic formulation

Alkaline products are commonly used in cosmetic preparations as neutralizing agents for acid-functional raw materials. Primary alkanolamines can provide positive attributes in such cases. The properties of nitroparaffin-derived primary alkanolamines are compared here with the general requirements for cosmetic-type acid-neutralizing materials.
Acid-functional copolymers, used as hair fixatives in both aerosol and non-aerosol products, are efficiently solubilized by neutralization with 2-amino-2-methyl-1-propanol (amino-methylpropanol) in a variety of aqueous and non-aqueous systems. The effects of such neutralization on resultant film properties which influence product performance are discussed in detail.
Upon neutralization, crosslinked acrylic-acid polymers of varying molecular weights (carbomers) provide significant benefits when used as thickeners, gellants or emulsifiers in cosmetic products. New data are added to previous knowledge on the use of tris(hydroxymethyl)aminomethane (tromethamine) as a neutralizing agent for three resins, especially in gelled formulations. Alcohol compatibility, pH behaviour, and viscosity characteristics of such formulations are described. In addition, toxicological considerations of primary alkanolamines are addressed.
Further to the above applications, nitroparaffin-derived primary alkanolamines can be effectively used as cosmetic emulsifiers (in the form of their fatty-acid soaps), dispersants or co-dispersants for particulate-containing products, and pH buffers/stabilizers.     

拉伸-定形处理对人发强伸性能的影响

人发及羊毛等角蛋白纤维经拉伸一定形处理后，其强伸性能发生了一定的变化。文中系统地研究了拉伸处理及拉伸一定形处理对人发强伸性能的影响。结果表明，毛发拉伸保护剂对人发纤维具有明显地保护作用，从而使该拉伸改性工艺在较短的时间内得到较高的定形效果和较好的综合机械性能。     

等离子体对兔毛表面改性的研究

兔毛纤维采用空气低温等离子体处理,使其形态结构和理化性能发生变化。从而提高兔毛纤维的表面摩擦系数,增加纤维抱合力,提高可纺性,减少掉毛。     

Evolution in the composition of human skin surface lipids during their accumulation on scalp and hair

Qualitative examination of human surface lipids collected using a surfactant solution shows that there are no significant differences between individuals when the samples are collected after one day, starting from clean hair and scalp. On the contrary, samples collected after 4 days reveal discrepancies within the population, related to the oily hair symptom.
An evolution in the composition of the recovered mixture occurs during the 1–4 days accumulation period, which mainly results in an increased unsaturation of the total (free + glycerides) fatty acids fraction isolated after saponification.
A two-step mechanism is proposed to account for the observed evolution: in a first step, free fatty acids are cleaved from glycerides by the well known enzymatic hydrolysis. Analytical determinations show that this process is structure dependant, the straight chain saturated acids being more readily hydrolyzable than the unsaturated and branched chain species. In a second step, free fatty acids are immobilized on the keratinic fibers, by a process which involves the formation of Ca salts.
This evolution results in a decreased viscosity of the skin surface lipids and in an increase of the low temperature melting fraction of the mixture. Its extent is more or less pronounced, depending upon the individuals. Subjects who exhibit extensive evolution are affected by the oily hair symptom.
Evolution de la composition des lipides superficiels humains durant leur accumulation sur le scalp et les cheveux     

Henné. Absorption de la lawsone par le cheveu

Une étude préalable par chromatographie sur couche mince des extraits de cheveux traités à la lawsone (No. CAS 83.72.7) ou au henné (feuille de Lawsonia inermis ) confirme que la lawsone est bien le seul colorant du henné'.
Nous avons mis au point une méthode originale de 'gravimétric dynamique'qui nous a permis de déterminer l'absorption de la lawsone par le cheveu traité au henné.
Après un retard à l'origine, l'accroissement de masse est linéaire en fonction de la racine carrée du temps indiquant un processus de diffusion , la courbe s'incurve ensuite vers la saturation. Une étude en fonction de la température confirme le phénomène de diffusion.
La lawsone diffuse plus rapidement dans le cheveu traité au henné que traitéà la lawsone seule. De même l'extraction de la lawsone fixée dans le cheveu est plus rapide quand il a été traité par la lawsone au lieu du henné.
La lawsone diffuse plus vite et en plus grande quantité dans les cheveux châtain et décoloré que dans le cheveu noir.
Dans une compétition entre le henné et des tanins : à la surface du cheveu les tanins l'emportent, á l'intérieur la lawsone l'emporte.
La lawsone fixée aux kératines semble ètre un bon écran solaire.
Henna. Sorption of lawsone by hair     

商品包装的色彩美学

论述了商品包装的色彩在年龄,性格,职业,情境等方面的运用,强调了“色彩就是财富”的思想。     

纤毛式MEMS传感器技术研究

首次综合国内外纤毛式MEMS传感器的研究成果,分别介绍了基于纤毛仿生原理的三维微触觉传感器、三维微力传感器、微声传感器、水流传感器、微几何测量传感器以及矢量水声传感器等。该类型传感器充分地将仿生学和MEMS技术结合起来,具有结构新颖精巧、体积小、功耗低、响应快、温漂小、精度高等优点,为开发具有自主知识产权的新型器件提供了新的思路。     

Effects of Combined Gentamicin and Furosemide Treatment on Cochlear Macrophages

Combining aminoglycosides and loop diuretics often serves as an effective ototoxic approach to deafen experimental animals. The treatment results in rapid hair cell loss with extended macrophage presence in the cochlea, creating a sterile inflammatory environment. Although the early recruitment of macrophages is typically neuroprotective, the delay in the resolution of macrophage activity can be a complication if the damaged cochlea is used as a model to study subsequent therapeutic strategies. Here, we applied a high dose combination of systemic gentamicin and furosemide in C57 BL/6 and CBA/CaJ mice and studied the ototoxic consequences in the cochlea, including hair cell survival, ribbon synaptic integrity, and macrophage activation up to 15-day posttreatment. The activity of macrophages in the basilar membrane was correlated to the severity of cochlear damage, particularly the hair cell damage. Comparatively, C57 BL/6 cochleae were more vulnerable to the ototoxic challenge with escalated macrophage activation. In addition, the ribbon synaptic deterioration was disproportionately limited when compared to the degree of outer hair cell loss in CBA/CaJ mice. The innate and differential otoprotection in CBA/CaJ mice appears to be associated with the rapid activation of cochlear macrophages and a certain level of synaptogenesis after the combined gentamicin and furosemide treatment.