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To investigate the internal structure changes in virgin black human hair keratin fibers due to aging, the structure of cross‐sections at various depths of virgin black human hair (sections of new growth hair: 2 mm from the scalp) from a group of eight Japanese females in their twenties and another group of eight Japanese females in their fifties were analyzed using Raman spectroscopy. For the first time, we have succeeded in recording the Raman spectra of virgin black human hair, which had been impossible due to high melanin granule content. The key points of this method are to cross‐section hair samples to a thickness of 1.50‐μm, to select points at various depths of the cortex with the fewest possible melanin granules, and to optimize laser power, cross slit width as well as total acquisition time. The reproducibility of the Raman bands, namely the α‐helix (α) content, the β‐sheet and/or random coil (β/R) content, the disulfide (SS) content, and random coil content of two adjoining cross‐sections of a single hair keratin fiber was clearly good. The SS content of virgin black human hair from the Japanese females in their fifties for the cortex region decreased compared with that of the Japanese females in their twenties. On the other hand, the β/R and α contents of the cortex region did not change. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 134–140, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

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In order to investigate the reduction mechanism of L-cysteine (Cys) on keratin fibers, cross-sectional samples of virgin white human hair treated with Cys were prepared. The heterogeneous reaction between Cys and keratin fibers involving the diffusion of Cys into human hair was analyzed at the molecular level using microspectrophotometry and Raman spectroscopy. The diffusion pattern of Cys into human hair showed non-Fickian type characteristics, thus indicating the free amino groups of electrostatically interacted with the anionic ions of the fiber surface. The disconnected relative concentration of -SS- groups at various depths of the hair samples with pH 9.0 was less than the Cys relative concentration, indicating that the reaction rate (the disconnection of -SS- groups) was slower than the diffusion rate of Cys into human hair. From these experiments, we concluded that the free amino groups of Cys electrostatically interacted with the anionic ions of the fiber surface, thereby decreasing the reaction rate (the disconnection of -SS- groups) of Cys at pH 9.0.

(PDA) coating can be used as an extremely versatile platform for tailoring of the coatings for diverse functional uses. Herein, we are inspired from the unique hierarchical structure of lotus leaf and the strong adhesion of mussel adhesive protein to simply develop a kind of superior superhydrophobic melamine foam through constructing a dopamine-induced lotus-leaf-like structure on melamine foam surface. Here, we choose the melamine foam (denoted MF foam) as an ideal starting material due to its commercial availability, low cost, good fl ame retardant, [ 22 ] light weight, high porosity, and robustness, all of which are highly desirable in a high-performance applied absorbent.With the combination of the amazing natural phenomena and the advanced material, a simple and mild three-step strategy is used to prepare the superhydrophobic foam. First, PDA coating proceeds through the simple dip-coating of the original hydrophilic MF foam in a basic solution of dopamine. Subsequently, the silver nanoparticles (Ag NPs) are formed by reduction and well distributed on the surface of PDA-coated MF foam. Finally, alkanethiol (1H, 1H, 2H, 2H-perfl uorodecanethiol) is used as hydrophobic molecules with low surface energy to react with both PDA and Ag NPs. After being modifi ed, the superhydrophobic MF foam is produced and exhibits excellent absorption and mechanical performances, including a high absorption capacity, robust stability, and extraordinary recyclability. The whole procedure was carried out under a mild condition and no special equipment was necessary. Furthermore, this approach is much more convenient, economical, and environmentally friendly than conventional processes for surface modifi cation. We believe that such biomimic novel superhydrophobic MF foam with high performance will have promising potential for practical applications and environmental protection.The mechanism of dopamine coating in basic solution is still disputed (e.g., supramolecular aggregation or polymerization), but the generally proposed and accepted one is the Michaeladdition reaction, in which the initial step involves an oxidation process between dopamine and O 2 . [ 23 ] With this inspiration, we found that high O 2 concentration in dopamine solution can extremely accelerate the PDA deposition process. Figure 1 a shows the dopamine concentration in solution decreases rapidly within 2 h under pure O 2 environment compared to that in ambient air. This agrees with the color change of dopamine solution quite well, as shown in Figure 1 b,c. Interestingly, MF foam shows excellent absorption to dopamine, the dopamine solution is still transparent even after stirring overnight. Moreover, the strong adhesion ability of PDA is confi rmed by ultrasonic treatment (See Movie S1, Supporting Information). The fast PDA deposition in the presence of pure O 2 and strong adhesion ability extremely favor its practical and industrial applications.Confronting the increasing environmental and ecological issues like the largest oil spillage event that happened i...

Core(TiO(2))/shell(SiO(2)) nanoparticles, with a void layer between the TiO(2) core and the silica layer, act as phase-selectivity photocatalysts for the photodecomposition of organic pollutants (gas phase) without any damage to their organic supports (solid phase).

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Thirteen dyestuffs of four chemical classes (quinophthalone, anthraquinone, isothiazole‐fused anthrone and pyridone azo) were applied for the dyeing of unmodified polypropylene fibres in supercritical carbon dioxide. From these 13 dyestuffs, three dyestuffs that have a pure yellow hue and good dyeability for polypropylene fibres were found. The results of a dyeability test using the 13 dyestuffs suggested that the affinity for polypropylene fibres requires, in the structural character of the dyestuff molecule, not only extreme hydrophobicity but also high aliphaticity. The isothiazole‐fused anthrone nonanamide dyestuff and two types of N‐butyl substituted pyridone azo dyestuffs were examined for build‐up and colour fastness properties. The light fastness of the dyed fabric was not so good. The ratings of fastness to washing, perspiration and rubbing ranged from excellent to fairly good with the increase of the depth of shade. From the relationship between the build‐up curve and the colour fastness, it was found that the dyestuff of the isothiazole‐fused anthrone nonanamide is suitable for polypropylene dyeing in a pale or medium shade, and that the two types of N‐butyl substituted pyridone azo dyestuffs are suitable in a deep shade.