88 semen samples from 39 bulls have been investigated by the quasi-elastic light scattering technique. Normal, defective, and dead cells each yielded characteristic autocorrelation functions. The form of these functions indicates that the swimming speed distribution of normal cells is a gamma distribution with two degrees of freedom while that for defective or circular swimmers is a gamma distribution with one degree of freedom. The resulting analysis of the experimental autocorrelation functions yields the fraction of the sample that is normal, the fraction that is defective, and the average speed of each group. The average helical swimming speed of normal cells was found to be 384 micron/s, while the average trajectory speed of the circular swimmers was found to be 103 micron/s. The overall quality of the semen samples as determined by light scattering is compared to quality determination on the same samples by technicians from the artificial insemination industry.

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Human hair can extract significant levels of calcium and magnesium, water hardness metals, from tap water immediately following chemical treatments and during hygiene practices. We have previously shown that this uptake is primarily a function of the condition of the hair. Depending on the extent of chemical damage, the hair can extract notable amounts of water hardness metals even from soft water. As water hardness metals concentrate primarily in the cuticle layers of the hair fibre, it is hypothesized that their presence will affect the structural properties that are chiefly driven by the cuticle. We examined hair mechanics and styling by technical measures of single-fibre torsional and tensile properties, combability and style retention as a function of the calcium and magnesium content of virgin and bleached hair. Our work has indicated that water hardness can affect hair properties. Fibre stiffening was induced by the presence of water hardness metals inside the fibres of both virgin and bleached hair. A reduction in combing forces was also observed, and this effect is believed to be a result of the stiffening. The style retention of virgin hair was improved by water hardness metals, whereas that of bleached hair was slightly reduced.

Coherent anti-Stokes Raman scattering (CARS) microscopy is used to determine the distribution and concentration of selected compounds in intact human hair. By generating images based on ratiometric CARS contrast, quantitative concentration maps of both water and externally applied d-glycine are produced in the cortex of human hair fibers. Both water and d-glycine are found to homogeneously distribute throughout the cortical regions of the hair. The ability to selectively detect molecular agents in hair fibers is of direct relevance to understanding the chemical and physical mechanisms that underlie the performance of hair-care products.

J. Cosmet. Sci., 60, 337–345 (May/June 2009) Accepted for publication December 29, 2008. Synopsis During hair coloring a number of disulfide bonds in cystine are oxidized (1) to create cysteic acid, forming binding sites for metal ions such as Ca2+ and Cu2+ from tap water (2). The increased uptake of these metals can have a detrimental impact on fiber properties—for example, reducing shine and causing a poor wet and dry feel (3). In addition, the increased uptake of copper can also contribute to further fiber damage during subsequent coloring due to its ability to take part in metal‐induced radical chemistry (4). It is important to know where in the fibers these metals are located in order to either effectively remove these metals or control their chemistry. Nanoscale secondary ion mass spectrometry (NanoSIMS) has been used to locate the calcium and copper within hair that has been treated with a colorant and washed multiple times in tap water containing these ions. Untreated hair is used as a baseline standard material. Images with up to 50‐nm spatial resolution of the preferential locations of calcium uptake were obtained, showing a high concentration of calcium in the cuticle region of colored hair, specifically in the sulfur‐rich regions (A‐layer and exocuticle).

This work aims to determine the roles of reactive oxygen species HO∙ and HO in the bleaching of melanins by alkaline hydrogen peroxide. Experiments using melanosomes isolated from human hair indicated that the HO∙ radical generated in the outside solution does not contribute significantly to bleaching. However, studies using soluble Sepia melanin demonstrated that both HO and HO∙ will individually bleach melanin. Additionally, when both oxidants are present, bleaching is increased dramatically in both rate and extent. Careful experimental design enabled the separation of the roles and effects of these key reactive species, HO∙ and HO. Rationalisation of the results presented, and review of previous literature, allowed the postulation of a simplified general scheme whereby the strong oxidant HO∙ is able to pre-oxidise melanin units to o-quinones enabling more facile ring opening by the more nucleophilic HO. In this manner the efficiency of the roles of both species is maximised.

This work provides evidence for the role of copper in UV-induced damage to hair and strategies to reduce copper levels in hair using a chelant such as EDDS.

The role of copper in accelerating UV damage to hair has been demonstrated as well as the ability of chelants such as EDDS and histidine in shampoo and conditioner products to reduce this damage.