STATEMENT OF PROBLEM Acrylic teeth of dentures are prone to discoloration due to frequent exposure to different colouring solutions in the oral environment. Thus, in order to maintain their aesthetic appearance, they must possess high colour stability while exposed to colorant solutions. OBJECTIVES To compare the colour stability of three different brands of acrylic teeth following immersion ...

Ontogenetic colour change is typically associated with changes in size, vulnerability or habitat, but assessment of its functional significance requires quantification of the colour signals from the receivers' perspective. The tropical python, Morelia viridis, is an ideal species to establish the functional significance of ontogenetic colour change. Neonates hatch either yellow or red and both ...

Dry thermal treatments of wood samples were carried out at 160 and 200 °C. After each treatment, the samples were irradiated using a strong UV emitter mercury lamp, and the colour change was then evaluated. For control, untreated samples were also irradiated using the same mercury lamp. Results showed that the extractive content of the wood played an important role in the colour change not only...

Habitat heterogeneity that occurs within an individual's lifetime may favour the evolution of reversible plasticity. Colour reversibility has many different functions in animals, such as thermoregulation, crypsis through background matching and social interactions. However, the mechanisms underlying reversible colour changes are yet to be thoroughly investigated. This study aims to determine th...

Trichromatic colorimetry was applied for the evaluation of the colour changes of the metallochromic indicators, viz., hematoxylin, gallocyanine, Gallamine Blue, Solochrome Prune AS, Celestine Blue, Eriochrome Black T, Xylenol Orange and Catechol Violet, in the complexometric titration of zirconium( IV) with ethylenediaminetetraacetic acid (EDTA) to measure the quality of colour change at the eq...

Many animals, particularly reptiles, amphibians, fish and cephalopods, have the ability to change their body colour, for functions including thermoregulation, signalling and predator avoidance. Many fish plastically darken their body colouration in response to dark visual backgrounds, and this functions to reduce predation risk. Here, we tested the hypotheses that colour change in fish (1) carr...

in this research we described the effective hamiltonian theory and applied this theory to the calculation of current-current (q1,2) and qcd penguin (q3,…,6) c quark decay rates. we calculated the decay rates of semileptonic and hadronic of charm quark in the effective hamiltonian theory. we investigated the decay rates of d meson decays according to spectator quark model (sqm) for the calculati...

Although it has been known since the 19th century that the tetragnathid spider Tylorida striata has the capability of rapidly changing colour, descriptions of this to date have been limited to simply noting that it darkens in response to disturbance. The process of rapid colour change by this species is described here formally, both qualitatively and quantitatively, for the first time. Submerge...