Search results for " pigment"

Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis.

2007

Oral melanoacanthoma (MA) is a rare, benign pigmented lesion, similar to cutaneous MA, characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes. The pathogenesis of oral MA remains uncertain, although its clinical behavior is suggestive of a reactive origin. The most common intraoral sites are the buccal mucosa, lip, palate and gingiva. The average age of presentation is 28 years, mainly in blacks, with a strong female predilection. The oral melanotic macule (MM) is a small, well-circumscribed brown-to-black macule that occurs on the lips and mucous membranes. The etiology is not clear and it may represent a physiologic or reactive process. The average age of presenta…

An Iranian booklet: non destructive examination by Energy Dispersive X-Ray Diffractometry and Micro-Raman Spectroscopy

2009

Energy Dispersive X-Ray Diffractometry was used in combination with micro-Raman Spectroscopy to study an undated illuminated Iranian booklet. In both cases, no preliminary preparation of the samples was needed: the data were acquired in a non-destructive way in a natural environment. The book is of particular interest because of the unusual presence of miniatures on some pages. The two techniques were used to collect data from small areas of the pages and in different regions of the miniature in order to identify inks and pigments and to attempt chronological assignment. Raman spectra were affected by strong background fluorescence. In spite of this, different peaks were detected and identi…

Dyskeratosis congenita: Report of a case with literature review

2007

Leukoplakic lesion is not uncommon in clinical practice but its occurrence as a component of a syndrome is rare. Dyskeratosis congenita is a rare genodermatosis, which is characterized by triad of skin pigmentation, nail dystrophy and leukoplakic lesion in the oral cavity. It is important for dentists to now about Dyskeratosis Congenita because these leukoplakic lesions can spontaneously undergo malignant transformation. Majority of cases have been reported in dermatology or pediatrics literature whereas only few reports have appeared in dental literature. The purpose of reporting this case with review of recent literature is to create better awareness among dentists about the multisystem m…

Oral Blue Nevus: Case Report

2016

Abstract: Aim of this research is the description of a case of palatal blue nevus and the diagnostic and therapeutic strategies to adopt when this oral lesion occurs. Nevi are benign proliferations of nevus cells either in the epithelium or in the subepithelial stroma. Blue nevus of the oral mucosa is a rare lesion. The oral blue nevi are asymptomatic and have no malignant potential. More importantly blue nevus had to be differentiated from malignant melanoma. Because is difficult to distinguish oral melanocytic nevi from melanoma we believe that any oral lesion in question should be excised and sent for histopathologic evaluation.

Differential diagnosis of diffused oral mucosal pigmented lesion: a case of Dubreuilh’s melanosis

2019

Sole coloration as an unusual aposematic signal in a Neotropical toad

2019

Many animals have evolved remarkable strategies to avoid predation. In diurnal, toxic harlequin toads (Atelopus) from the Amazon basin, we find a unique colour signal. Some Atelopus populations have striking red soles of the hands and feet, visible only when walking. When stationary, the toads are hard to detect despite their yellow-black dorsal coloration. Consequently, they switch between high and low conspicuousness. Interestingly, some populations lack the extra colour display of the soles. We found comprehensive support that the red coloration can act as an aposematic signal directed towards potential predators: red soles are significantly more conspicuous than soles lacking red colora…

La problematica del colore negli "smaltini di calcara" palermitani

2008

Montmorilonīta-antociānu organokompleksi: fizikāli ķīmiskās īpašības un izmantošanas risinājumi

2020

Bakalaura darba ietvaros tika pētīta antociānu interkalācija montmorilonīta struktūrā un veikta iegūtā organokompleksa fizikāli ķīmisko īpašību izpēte inovatīvu un videi draudzīgu materiālu izstrādē. Pētījuma ietvaros izvēlēts rūpnieciski ražots māla minerāls- montmorilonīts, kas tika modificēts ar antociāniem no melnaugļu aroniju ogu (Aronia melanocarpa L.) vai vīnogu (Vitis vinifera) izspiednēm. Antociānu sorbcija uz māla minerāla tika pētīta atkarībā no sorbenta iesvara, sorbāta koncentrācijas, vides pH un temperatūras. Iegūto kompozītmateriālu īpašības tika raksturotas ar Furjē transformācijas infrasarkanās gaismas spektroskopijas (FTIS) un termogravimetrijas analīzes (TGA) metodēm. Ieg…

Long-term changes in pigmentation of arctic Daphnia provide potential for reconstructing aquatic UV exposure

2016

Abstract Despite the biologically damaging impacts of solar ultraviolet radiation (UV) in nature, little is known about its natural variability, forcing mechanisms, and long-term effects on ecosystems and organisms. Arctic zooplankton, for example the aquatic keystone genus Daphnia (Crustacea, Cladocera) responds to biologically damaging UV by utilizing photoprotective strategies, including pigmentation. We examined the preservation and content of UV-screening pigments in fossil Daphnia remains (ephippia) in two arctic lake sediment cores from Cornwallis Island (Lake R1), Canada, and Spitsbergen (Lake Fugledammen), Svalbard. The aims were to document changes in the degree of UV-protective p…