Humans use color to judge the ‘value’ or quality of a product, often comparing and choosing a product based on expectations and past experiences. Choices made based on visual evaluation, which requires no physical contact, pose very little risk; therefore, when a product does not meet ‘color expectations’, it is an easy decision deem a product ‘unacceptable’. Color is produced when energy in th...

The depth distribution of reef-building corals exposes their photosynthetic symbionts of the genus Symbiodinium to extreme gradients in the intensity and spectral quality of the ambient light environment. Characterizing the mechanisms used by the coral holobiont to respond to the low intensity and reduced spectral composition of the light environment in deeper reefs (greater than 20 m) is funda...

Most opsins selectively bind 11-cis retinal as a chromophore to form a photosensitive pigment, which underlies various physiological functions, such as vision and circadian photoentrainment. Recently, opsin 3 (Opn3), originally called encephalopsin or panopsin, and its homologs were identified in various tissues including brain, eye, and liver in both vertebrates and invertebrates, including hu...

A mixture of extracts from two common vegetables, red pomegranate and turmeric, when photoexcited at 380 nm, produced almost pure white light emission (WLE) with Commission Internationale d'Eclairage (CIE) chromaticity index (0.35, 0.33) in acidic ethanol. It was also possible to obtain WLE in polyvinyl alcohol film (0.32, 0.25), and in gelatin gel (0.26, 0.33) using the same extract mixture. T...

A minimal, one-parameter model of the excitonic Hamiltonian for the light harvesting complex of purple bacteria (LH2) based on ab initio calculation of the excitonic energies is proposed. The set of input parameters contains positions of atoms in 27 bacteriochlorophyll pigments only. The excitation energies, transition dipole and quadrupole moments of the bacteriochlorophyll units were calculat...

Specific colours observed in images of the ocular fundus depend on the architecture of its layers and the optical properties and quantities of any pigments present. These colours can be predicted from the parameters describing the ocular tissue composition using a physics-based model of light transport. This paper reports preliminary results of the application of the inverse process by which th...

Action spectra were obtained for photosystems I and II in chemically fixed algal cells and for photosystem I in unfixed lysozyme treated cells. Untreated algal cells yielded neither of the 2 light reactions with the reaction mixtures used. The action spectra for photosystem I in the blue-green alga Anacystis nidulans and red alga Porphyridium cruentum follow the absorption spectrum of chlorophy...

Absorption spectra of several phytoplankton species were decomposed, after correction for the particle effect, to estimate in vivo absorption properties of the major light-harvesting pigments in algae. A Gaussian shape is suitable, theoretically and empirically, to represent the absorption spectra of individual photosynthetic components. The Gaussian parameters agreed well with the expected pig...

Investigations have been carried out in recent years in an effort to improve the color of various fruits. Citrus and other semitropical fruits, in particular, have received the most attention. Several studies of the factors influencing the formation of the red pigment of apples have been made. In general, such studies have included the influence of light, fertilization, pruning, and artificial ...