Results 181 to 190 of about 6,578 (220)
Some of the next articles are maybe not open access.
Elucidating the Photoprotection Mechanism of Eumelanin Monomers
The Journal of Physical Chemistry B, 2017Eumelanin, the functional polymer in human skin, forms a heterogeneous layered structure intrinsic to its broadband monotonic spectra. The inherent structural heterogeneity of eumelanin makes the photoprocesses very complex and diverse in nature. Due to this diversity, a complete mechanistic picture of these photoprocesses, essential to understanding ...
Paulami Ghosh, Debashree Ghosh
openaire +2 more sources
Solvochromic Effects in Model Eumelanin Compounds†
Photochemistry and Photobiology, 2008ABSTRACTWe have created an indolic compound which is ideally suited to the study of the relationship between structure and function in eumelanin formation. N‐methyl‐5‐hydroxy‐6‐methoxyindole (MHMI) is stable in solid and liquid states, highly soluble in a variety of solvents and forms a dimer only through the 4‐4′ positions.
Nighswander-Rempel, Stephen P. +4 more
openaire +6 more sources
Establishing structure–function relationships for eumelanin
Biopolymers, 2002AbstractThe aggregation‐dependent optical properties of eumelanin from human hair are examined. When aggregation is increased, the absorption spectrum extends to lower energy. The absorption spectra of oligomers isolated from black human hair and Sepia officinalis are comparable and are in quantitative agreement with the reported action spectra for ...
J Brian, Nofsinger +2 more
openaire +2 more sources
Reactivity of eumelanin building blocks: A DFT study of monomers and dimers.
Journal of Molecular Graphics and Modelling, 2020Melanins are natural pigments with important biological properties and have been considered promising materials for several bio-electronic applications.
Gabriel G. B. Alves +3 more
semanticscholar +1 more source
Speculations on the molecular structure of eumelanin
International Journal of Cosmetic Science, 2009SynopsisEumelanin is the polymeric black pigment commonly found in hair and skin. Its chemical intractability, to all but vigorous oxidizing agents, has hindered satisfactory understanding of its molecular structure. It is well‐established that the immediate precursor to polymerization, indole‐5,6‐quinone (IQ), is biosynthesized from the amino acid ...
openaire +2 more sources
Mechanism of UVA Degradation of Synthetic Eumelanin
Biomacromolecules, 2019Eumelanin is a ubiquitous natural pigment that has a broad absorption across ultraviolet (UV, 100-400 nm) and visible wavelengths (400-700 nm) and can protect against radiation. Synthetic eumelanin with properties similar to natural eumelanin has been made using dopamine or dihydroxyindole.
Weiyao Li +10 more
openaire +2 more sources
Charge Transport in Eumelanin [PDF]
Melanins are a class of bio-macromolecules that are found throughout the biosphere. They fulfill various functions in human beings, which makes them a long studied substance in medicine and biology. Furthermore they possess a set of rare and special physico-chemical properties which include featureless broad band absorption in the UV-Vis spectrum and ...
openaire +1 more source
Spectrophotometric Characterization of Eumelanin and Pheomelanin in Hair
Pigment Cell Research, 1996Mammalian melanins exist in two chemically distinct forms: the brown to black eumelanins and the yellow to reddish‐brown pheomelanins. They can be quantified by HPLC analysis of pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and aminohydroxyphenylalanine (AHP).
H, Ozeki +3 more
openaire +2 more sources
Spectrophotometric Assay of Eumelanin in Tissue Samples
Analytical Biochemistry, 1993Most of the natural melanin pigments consist of not only indolic eumelanin but also sulfur-containing pheomelanin. Previous methods for spectrophotometric assay of melanins use solubilization in alkaline media; a major disadvantage of these procedures is that they do not distinguish between eumelanin and pheomelanin.
S, Ito, K, Wakamatsu, H, Ozeki
openaire +2 more sources
A Hierarchical Self-Assembly of Eumelanin
The Journal of Physical Chemistry B, 2000Atomic force microscopy is used to examine the structure of a natural eumelanin isolated from the ink sacs of cuttlefish (Sepia officinalis). The experimental data presented clearly show that the 100−200 nm spherical eumelanin particles imaged previously by SEM are not a fundamental structural unit. While these spherical particles are stable structures,
Christine M. R. Clancy +3 more
openaire +1 more source