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Trends in Ecology & Evolution Apr 2020Mammalian colors and color patterns are some of the most diverse and conspicuous traits found in nature and have been widely studied from genetic/developmental and... (Review)
Review
Mammalian colors and color patterns are some of the most diverse and conspicuous traits found in nature and have been widely studied from genetic/developmental and evolutionary perspectives. In this review we first discuss the proximate causes underlying variation in pigment type (i.e., color) and pigment distribution (i.e., color pattern) and highlight both processes as having a distinct developmental basis. Then, using multiple examples, we discuss ultimate factors that have driven the evolution of coloration differences in mammals, which include background matching, intra- and interspecific signaling, and physiological influences. Throughout, we outline bridges between developmental and functional investigatory approaches that help broaden knowledge of mammals' memorable external appearances, and we point out areas for future interdisciplinary research.
Topics: Animals; Biological Evolution; Color; Mammals; Phenotype; Pigmentation
PubMed: 31980234
DOI: 10.1016/j.tree.2019.12.008 -
Current Biology : CB Aug 2021Bevil Conway introduces colors.
Bevil Conway introduces colors.
Topics: Color; Color Perception
PubMed: 34428415
DOI: 10.1016/j.cub.2021.06.072 -
Molecules (Basel, Switzerland) Jan 2019Although there is no legal and clear definition of the term "natural food colorant", the market trends, and consequently industrial and commercial interest, have turned... (Review)
Review
Although there is no legal and clear definition of the term "natural food colorant", the market trends, and consequently industrial and commercial interest, have turned to foods with added natural pigments. This progressive substitution of artificial colorants has faced chemical complications with some colors, with a lack of stable green hues being one of them. Several strategies have been applied for green color stabilization in processed foods, from the formation of metallochlorophylls to the microencapsulation of green pigments. However, at present, the utilization of green coloring foodstuffs, which are considered an ingredient in the EU, seems to be the more successful solution for the market. Besides those topics, the present review aims to clarify the current confusion between the different chlorophyll compounds that form part of the authorized green food colorants. In this sense, legislations from different countries are compared. Finally, and in line with current concerns, the knowledge gathered so far in relation to the absorption, distribution, metabolism and excretion of all green natural food colorants is reviewed.
Topics: Biological Products; Chlorophyll; Color; Complex Mixtures; Coordination Complexes; Food Coloring Agents; Green Chemistry Technology; Molecular Structure; Pigments, Biological; Solid Phase Extraction; Structure-Activity Relationship
PubMed: 30609768
DOI: 10.3390/molecules24010154 -
Nature Communications Jul 2022Structural colors have a demonstrated value in constructing various functional materials. Efforts in this area are devoted to developing stratagem for generating...
Structural colors have a demonstrated value in constructing various functional materials. Efforts in this area are devoted to developing stratagem for generating heterogeneous structurally colored materials with new architectures and functions. Here, inspired by icing process in nature and ice-templating technologies, we present freeze-derived heterogeneous structural color hydrogels with multiscale structural and functional features. We find that the space-occupying effect of ice crystals is helpful for tuning the distance of non-close-packed colloidal crystal nanoparticles, resulting in corresponding reflection wavelength shifts in the icing area. Thus, by effectively controlling the growth of ice crystals and photo-polymerizing them, structural color hydrogels with the desired structures and morphologies can be customized. Other than traditional monochromatic structure color hydrogels, the resultant hydrogels can be imparted with heterogeneous structured multi-compartment body and multi-color with designed patterns through varying the freezing area design. Based on these features, we have also explored the potential value of these heterotypic structural color hydrogels for information encryptions and decryptions by creating spatiotemporally controlled icing areas. We believe that these inverse ice-template structural color hydrogels will offer new routes for the construction and modulation of next generation smart materials with desired complex architectures.
Topics: Color; Freezing; Hydrogels; Ice; Nanoparticles
PubMed: 35831308
DOI: 10.1038/s41467-022-31717-2 -
Journal of Medicine and Life 2016To verify the impact of taking the Toothguide Training Box (TTB) exercise in improving the individual ability to correctly determine dental color. A prospective study...
UNLABELLED
To verify the impact of taking the Toothguide Training Box (TTB) exercise in improving the individual ability to correctly determine dental color. A prospective study was conducted on the 5th year dental students. The participants were required to carry out 3 distinct steps: visual color determination for sample tabs out of the 3DMaster shade guide, the TTB exercise and another color determination after training completion. The sample included 60 students (19M/ 41F) with a mean age of 24, which made 360 color determinations of 6 shade tabs before and after TTB exercise. 32,5% (n=117) of the color determinations were incorrect in both moments, and the value was incorrectly determined just in 11% of them. Students found 3L1.5 and 3M2 colors as the hardest to determine. The results suggested that a single TTB training exercise did not have a high positive influence on the individual capacity to correctly determine the color for tabs out of the shade guide. While there is no evidence of an immediate positive impact of the TTB exercise in evaluating and determining different color variations for sample key elements, through repeat exercises, the individual perception can be improved and thus the correct determination of dental color and its correct codification can be increased.
ABBREVIATIONS
TTB = Tooth Training Box, CIE = Commission internationale de l'éclairage, L = lightness, C = chroma, H = hue.
Topics: Adult; Color; Color Perception; Female; Humans; Male; Prospective Studies; Prosthesis Coloring
PubMed: 27974916
DOI: No ID Found -
Trends in Ecology & Evolution Feb 2024Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' - parts of an animal that appear colorful compared... (Review)
Review
Color signals which mediate behavioral interactions across taxa and contexts are often thought of as color 'patches' - parts of an animal that appear colorful compared to other parts of that animal. Color patches, however, cannot be considered in isolation because how a color is perceived depends on its visual background. This is of special relevance to the function and evolution of signals because backgrounds give rise to a fundamental tradeoff between color signal detectability and discriminability: as its contrast with the background increases, a color patch becomes more detectable, but discriminating variation in that color becomes more difficult. Thus, the signal function of color patches can only be fully understood by considering patch and background together as an integrated whole.
Topics: Animals; Color; Predatory Behavior
PubMed: 37802667
DOI: 10.1016/j.tree.2023.09.006 -
Chemical Reviews May 2016Natural anthocyanin pigments/dyes and phenolic copigments/co-dyes form noncovalent complexes, which stabilize and modulate (in particular blue, violet, and red) colors... (Review)
Review
Natural anthocyanin pigments/dyes and phenolic copigments/co-dyes form noncovalent complexes, which stabilize and modulate (in particular blue, violet, and red) colors in flowers, berries, and food products derived from them (including wines, jams, purees, and syrups). This noncovalent association and their electronic and optical implications constitute the copigmentation phenomenon. Over the past decade, experimental and theoretical studies have enabled a molecular understanding of copigmentation. This review revisits this phenomenon to provide a comprehensive description of the nature of binding (the dispersion and electrostatic components of π-π stacking, the hydrophobic effect, and possible hydrogen-bonding between pigment and copigment) and of spectral modifications occurring in copigmentation complexes, in which charge transfer plays an important role. Particular attention is paid to applications of copigmentation in food chemistry.
Topics: Anthocyanins; Color; Coloring Agents; Hydrogen Bonding; Phenols; Pigments, Biological
PubMed: 26959943
DOI: 10.1021/acs.chemrev.5b00507 -
Current Biology : CB Jun 2015In this Quick Guide, Steven Buck explains how, uniquely among the bright primary perceptual hues, yellow changes its hue when it appears dark, becoming the colour brown.
In this Quick Guide, Steven Buck explains how, uniquely among the bright primary perceptual hues, yellow changes its hue when it appears dark, becoming the colour brown.
Topics: Color; Color Perception; Humans; Light
PubMed: 26126275
DOI: 10.1016/j.cub.2015.05.029 -
AAPS PharmSciTech Mar 2010Drying is one of the standard unit operations in the pharmaceutical industry and it is important to become aware of the circumstances that dominate during the process....
Drying is one of the standard unit operations in the pharmaceutical industry and it is important to become aware of the circumstances that dominate during the process. The purpose of this study was to test microcapsulated thermochromic pigments as heat indicators in a fluid bed drying process. The indicator powders were manually granulated with alpha-lactose monohydrate resulting in three particle-size groups. Also, pellets were coated with the indicator powders. The granules and pellets were fluidized in fluid bed dryer to observe the progress of the heat flow in the material and to study the heat indicator properties of the indicator materials. A tristimulus colorimeter was used to measure CIELAB color values. Color indicator for heat detection can be utilized to test if the heat-sensitive API would go through physical changes during the pharmaceutical drying process. Both the prepared granules and pellets can be used as heat indicator in fluid bed drying process. The colored heat indicators give an opportunity to learn new aspects of the process at real time and could be exploded, for example, for scaling-up studies.
Topics: Color; Desiccation; Excipients; Hot Temperature; Indicators and Reagents; Particle Size; Powders
PubMed: 20039220
DOI: 10.1208/s12249-009-9351-x -
Current Biology : CB Feb 2021The geometry that describes the relationship among colors, and the neural mechanisms that support color vision, are unsettled. Here, we use multivariate analyses of...
The geometry that describes the relationship among colors, and the neural mechanisms that support color vision, are unsettled. Here, we use multivariate analyses of measurements of brain activity obtained with magnetoencephalography to reverse-engineer a geometry of the neural representation of color space. The analyses depend upon determining similarity relationships among the spatial patterns of neural responses to different colors and assessing how these relationships change in time. We evaluate the approach by relating the results to universal patterns in color naming. Two prominent patterns of color naming could be accounted for by the decoding results: the greater precision in naming warm colors compared to cool colors evident by an interaction of hue and lightness, and the preeminence among colors of reddish hues. Additional experiments showed that classifiers trained on responses to color words could decode color from data obtained using colored stimuli, but only at relatively long delays after stimulus onset. These results provide evidence that perceptual representations can give rise to semantic representations, but not the reverse. Taken together, the results uncover a dynamic geometry that provides neural correlates for color appearance and generates new hypotheses about the structure of color space.
Topics: Color; Color Perception; Color Vision; Magnetoencephalography; Semantics
PubMed: 33202253
DOI: 10.1016/j.cub.2020.10.062