Internal structural changes in age-related curved hair due to cyclical extension: An IR spectroscopy study.

Objective: This study aimed to identify structural changes in age-related curved hair (referred to as "YUGAMI" hair in Japanese) induced by cyclical extension using infrared (IR) spectroscopy coupled with chemometrics, such as multivariate curve resolution (MCR) and two-dimensional correlation spectroscopy (2DCOS).

Methods: The hair fibres were stretched at a strain level of 0.3-N, and this operation was counted as one cycle and was repeated 500 cycles.

Age-related hair denaturation related to protein carbonyls.

Objective: Hair ageing is accompanied by hair fibres becoming irregularly shaped causing them to stick out in irregular directions or have more curliness and being spread out. This is believed to be due to changes within the hair fibre structure which occur with ageing, and one of the causes of these changes could be an increase in the number of protein carbonyl groups present in the hair. The aim of this study is to investigate the internal denaturation of hair related to protein carbonyls in attempt to gain new insight into age-related changes that occur in hair.

Prediction of breakage in human hair caused by cyclical extension using infrared spectroscopy coupled with multivariate curve resolution.

We propose a method of prediction for hair breakage induced by change of molecular structure. The changes inside hair by cyclical extension were investigated using infrared (IR) spectroscopy coupled with multivariate curve resolution (MCR) and two-dimensional correlation spectroscopy (2D-COS). In bleached hair, cyclical extension stresses at 5% strain levels were seen to increase the signal of CH and that of component primarily derived from C=O at 55 cycles, SOH signal at 75 cycles, ultimately leading to fiber breakage.

Temporal and spatial visualization of water uptake into human hair studied by infrared microscopy.

Real-time examination of water behavior in cuticle, cortex, and medulla of untreated and bleached hair was performed by Fourier-transform infrared (FT-IR) microscopy. Penetration of heavy water from the cuticle to the medulla was visualized and quantified by monitoring the O-D stretching band located at 2500 cm. The medulla of untreated hair had a significantly higher peak O-D intensity from 20 min after the heavy water penetration to 20 min after drying than that of bleached hair.

Microstructural Characterization of Foam Formed by a Hydroxy Group-Containing Amino Acid Surfactant Using Small-Angle Neutron Scattering.

Small-angle neutron scattering, which has not been extensively utilized for foam characterization, can provide important insights into the microstructure of surfactant-stabilized foam. Small-angle neutron scattering in combination with several other techniques was herein employed to determine the microstructure of foams stabilized by hydroxy group-containing (C-EtOH-βAla) and hydroxy group-free (C-Me-βAla) surfactants of the amino acid type. Hydroxy group introduction at the amide nitrogen had no effect on the foam film thickness (∼26 nm in both cases) but increased the foam stability and suppressed draining, as hydrogen bonding between hydroxy groups and carboxylate ions increased the foam film strength.