in a completely randomized design, the effect of the extract from trifolium alexandrium (0, 0.2 and 0.4%) on the germination, some morphological characteristics, photosynthetic pigments, and nutrients uptake of prosopis cineraria was evaluated. the highest germination rate and percentage (9.16 and 21%, respectively) were recorded in the 0.2% treatment. the maximum and minimum lengths of radicle...

 The performance of black pigments used in thickness sensitive solar selective absorbing paints for solar thermal collectors depend on the optical properties of the pigments. Knowledge of the intrinsic optical properties of most paint pigments is very limited. Pellets made from either FeMnCuOx or black carbon dispersed in KBr matrix have been used to determine the effective optical coefficient...

The toxicity problems caused by those of synthetic origin pigments to the environment have created a mounting interest towards natural pigments. Among natural pigments, pigments from microbial sources are potentially good alternative ones to synthetic pigments. Prodigiosin, the bright red pigment produced by organisms of the genus Serratia, is among the more conspicuous pigments extant in the m...

BACKGROUND The composition of cosmetic tattoos might prove relevant to their treatment by high-powered lasers. OBJECTIVES To test the accuracy and completeness of information supplied by the tattoo ink manufacturers and to perform an elemental assay of tattoo pigments using scanning electron microscopy with energy-dispersive x-ray analysis. DESIGN Samples of 30 tattoo inks were examined usi...

Vertebrate vision is mediated by five groups of visual pigments, each absorbing a specific wavelength of light between ultraviolet and red. Despite extensive mutagenesis analyses, the mechanisms by which contemporary pigments absorb variable wavelengths of light are poorly understood. We show that the molecular basis of the spectral tuning of contemporary visual pigments can be illuminated only...

Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs). These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection...

A central unanswered question in phototransduction is how photosensitive molecules, visual pigments, regulate their absorption spectra. In nature, there exist various types of visual pigments that are adapted to diverse photic environments. To elucidate the molecular mechanisms involved in the adaptive selection of these pigments, we have to identify amino acid changes of pigments that are pote...

Using Resonance Raman microspectrometry we identify polyenes as shell pigments in 13 gastropod, 1 cephalopod and 4 bivalve taxa. The pigments are either isolated polyenes or polyenes bound to other molecules. Polyenes are present in coloured parts of the shell of all investigated taxa. Pigments differ between taxa and there is no trivial relationship between colour, pigment and taxon. The same ...

The nonbleaching yellow pigments of the primate fovea were studied by microspectrophotometry (MSP). Retinas fixed with glutaraldehyde/paraformaldehyde mixtures retained yellow pigments with absorbance spectra very similar to those recorded by MSP in fresh retinas. This allowed the authors to prepare retinal sections for localization of the pigments. The spectrum of the macular pigment in fixed ...

Studies of the spectral reflectance of the eggs of 25 species of birds from nine families disclosed uniformly high reflectance (often above 90 percent) in the near infrared. This property is associated with the presence of the eggshell pigments protoporphyrin and the bilins. These pigments allow coloration for cryptic or other purposes with minimum solar heating, a combination not possible with...