Melanins
Mostrando 1-12 de 32 artigos, teses e dissertações.
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1. Análise da redução da alcalinidade de compósitos cimento-madeira em função da substituição parcial do cimento Portland por pozolanas
RESUMO O objetivo desta pesquisa foi avaliar a redução da alcalinidade de compósitos cimento-madeira, produzido com cimento Portland e partículas residuais de Pinus spp., em função da substituição gradual do cimento Portland pelas pozolanas sílica ativa (SA) metacaulim (MK), cinza volante (CV), escória de alto-forno (EAF), cinza de casca de arroz (
Matéria (Rio J.). Publicado em: 25/11/2019
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2. Optical (DRUV-VIS) and magnetic (EPR) behavior of synthetic melanins
The properties of melanins prepared from L-dopa oxidation by both chemical and electrochemical methods are reported, searching for a material with more intense optical absorption in the visible region. The characterization of the samples have been done by cyclic voltammetry (CV), cronoamperometry (CA), Fourier transformed infrared spectroscopy (FTIR), electr
Materials Research. Publicado em: 06/03/2012
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3. Chá mate (Ilex paraguariensis): compostos bioativos e relação com atividade biológica / Mate tea (Ilex paraguariensis): bioactive compounds and relationship with biological activity
Introduction: Yerba maté (Ilex paraguariensis St. Hilaire) is a spontaneous species that grows in Brazil, Argentina and Paraguay and several beverages (chimarrão, terere, maté tea) are produced from its leaves. Maté tea, one of I. paraguariensis beverages present antioxidant activity and other biological effects. Compounds such as aponins, polyphenols an
Publicado em: 2009
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4. Estrutura eletronica de precursores de alomelaninas / Electronic structure of allomelanins precursors
In this work we studied, on the basis of a semiempirical and ab initio approaches, the structure and electronic properties of some allomelanins precursors. Allomelanins are part of an ubiquitous class of dark pigments known as melanins and their precursors are formed by monomers of catechol and o-benzoquinone units. Due to the lack of extensive experimental
Publicado em: 2008
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5. Estrutura eletronica de melaninas solvatadas / Electronic structure of solvated melanins
As melaninas constituem uma classe de pigmentos biológicos de destaque devido, sobretudo, a sua predominante presença nos tecidos dos mamíferos. Há fortes evidências que sugerem que a pigmentação por melanina tem por objetivo proteger a pele contra efeitos prejudiciais da radiação ultravioleta. Além deste papel de fotoproteção, outras funções b
Publicado em: 2007
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6. Avaliação dos achados clínicos e histopatológicos nas lesões de poiquilodermia de Civatte antes e após o tratamento com luz intensa pulsada / An evaluation of the clinical and histopathological findings of the lesions of poikiloderma of Civatte before and after treatment with intense pulsed light
A poiquilodermia de Civatte é uma condição caracterizada por hiperpigmentação, telangiectasia e atrofia que acomete predominantemente o pescoço e a face de forma simétrica, poupando a área encoberta pelo mento. A sua ocorrência é associada à predisposição genética, à exposição cumulativa ao sol, ao processo de envelhecimento, à hipersensibi
Publicado em: 2005
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7. Um estudo teorico das propriedades estruturais e oticas de derivados de Eumelanina
Melanins are a class of biological pigments widely spread over in nature from fungi to man. They are roughly classified in three great subclass: eumelanins, pheomelanins and allomelanins. In this work we restrict ourselves to investigate the subclass of eumelanins, the pigment present in most pigmented animal tissues. It is believed that the main biological
Publicado em: 1997
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8. Estrutura eletronica das melaninas
Melanin?s form a class of biological pigments which presents photoprotection as its basic function and amorphous semiconductor features. Though the structure and composition of these pigments are not well characterized, there is no doubt 5,6,indolquinone (lQ) is the most important monomer related to them. In this work we have studied the electronic structure
Publicado em: 1989
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9. Melanization of Cryptococcus neoformans and Histoplasma capsulatum Reduces Their Susceptibilities to Amphotericin B and Caspofungin
The fungal pathogens Cryptococcus neoformans and Histoplasma capsulatum produce melanin-like pigments in the presence of l-dopa in vitro and during mammalian infection. We investigated whether melanization affected the susceptibilities of the fungi to amphotericin B, caspofungin, fluconazole, itraconazole, or flucytosine (5FC). Using the standard macrodiluti
American Society for Microbiology.
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10. Is there any difference in the photobiological properties of melanins isolated from human blue and brown eyes?
Investigations were carried out to determine whether the melanin present in the blue and brown eyes were eumelanin, the melanin present in black hair and dark skin, or pheomelanin, the melanin present in red hair and the skin of people with red hair. Our results showed that UV-visible irradiation of blue or brown eye melanin did not produce any superoxide. I
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11. Activation of the Alternative Complement Pathway by Fungal Melanins
Melanins are complex biological pigments formed by the oxidative polymerization of phenolic and/or indolic compounds. These pigments have been implicated in the pathogenesis of some microbial infections, malignancies, degenerative disorders, and autoimmune diseases. Recent studies have demonstrated that melanins have antigenic and anti-inflammatory propertie
American Society for Microbiology.
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12. The Melanins. I. Studies of the Hair Pigments of the Guinea Pig