Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 11 of 11 for “"Melanins"”.
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Molecular characterization and effect of diagenesis and maturation of melanin in the fossil record
… and distribution in the fossil record. Melanins are polymeric phenolic compounds classified into two major groups based in their chemical structures and molecular precursors: eumelanin (dark brown-black in color) and pheomelanin (orange-red in color). Both eumelanin and pheomelanin are …
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The role of melanin production in the survival of Vibrio cholerae in the marine environment
… to homogentisic acid. Various types of melanins are used by microbes as defense mechanisms against a variety of environmental stresses. This thesis investigated the defensive role of V. cholerae pyomelanin against exogenous stresses, particularly hydrogen-peroxide (H2O2).
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Increased biopolymer pigment production in bacteria and fungi exposed to ionizing radiation
… exploration of the potential of pigments, like melanins and carotenoids, to protect from and react to ionizing radiation in the context of space. Certain bacteria and fungi show a remarkable ability to persist, and even thrive, in high-radiation environments⁴. The bacteria of interest in this …
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Identification and biophysical characterization of two intralysosomal pigments with free-radical properties and their synthetic models: Human neuromelanin and the minocycline-induced thyroid pigment
Melanins are complex, incompletely understood polymeric pigments which uniquely contain a stable population of organic free radicals amenable to study by electron paramagnetic resonance (EPR, or equivalently, electron spin resonance, ESR) spectroscopy. In contrast to the usual histochemical tests, …
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A new catoptric system in the eyes of penaeid shrimp
… Absorbing pigments are believed to be melanins or ommochromes (Kleinholz, l96l), whereas the reflecting material by analogy with vertebrate systems, has long been considered to be guanine. More recently, it has been found to include a number of purines and the pteridine, xanthopterin …
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Phenolic reactions for leather tanning and dyeing
… versions of natural black, brown and orange melanins. These reactions can be catalysed by laccase; not only do they create colour, but also if they are conducted in the presence of collagen, the resulting pigment is bound to the leather in a covalent tanning manner. Therefore, the leather …
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The <i>C. neoformans</i> Cell Wall: A Scaffold for Virulence
… of this organism is the production of melanin. Melanins are a class of diverse pigments produced via the oxidation and polymerization of aromatic ring compounds that have a characteristically complex, heterogenous, and amorphous structure. They are synthesized by representatives of all …
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Deterination of the melanin content in the skin of albinos at the University Teaching Hospital, Lusaka, Zambia
BACKGROUND: Melanin is a skin pigment that determines skin colour and plays a role in photoprotection. It represents one of the most visible markers of human variation and skin disorders. Lack of Melanin or presence of very little melanin or albinism makes the skin susceptible to a wide range of …
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Deterination of the melanin content in the skin of albinos at the University Teaching Hospital, Lusaka, Zambia
BACKGROUND: Melanin is a skin pigment that determines skin colour and plays a role in photoprotection. It represents one of the most visible markers of human variation and skin disorders. Lack of Melanin or presence of very little melanin or albinism makes the skin susceptible to a wide range of …
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The Albino Mouse Visual System: How Perturbed Retinal Development Leads to Altered Binocular Projections
Albinism is a heterogeneous disorder that occurs when one of several genetic defects causes a disruption in melanin synthesis in the hair, skin, and eyes. Every form of albinism results in hypopigmentation in the retinal pigment epithelium (RPE), the monolayer of epithelial cells surrounding the …
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Perceptions of dark-skinned beauty on social media using social identity theory : the case of #melaninmagic on Instagram
Thesis submitted in fulfillment of the requirement of the degree Master in Journalism, Durban University of Technology, Durban, South Africa, 2022.