Search results for " Pigments"
showing 10 items of 52 documents
Indagine composizionale sulle pitture di due vasi di Centuripe
2019
Due vasi Centuripe a Palermo sono stati analizzati utilizzando XRF portatile complementare e FTIR a riflessione totale spettroscopie. Le analisi consentono di chiarire la tavolozza e la tecnica della decorazione (pittura a tempera con un legante organico), e mostrano la presenza di pigmenti sia antichi che moderni (a causa di qualche recente riverniciatura). Uno dei risultati più interessanti è stata l'identificazione di due fasi del solfato di calcio nello strato sottostante i dipinti: a causa delle condizioni che trasformano il gesso in bassanite, la presenza di il gesso o, in alternativa, la bassanite in ciascuna parte analizzata possono rappresentare un criterio per distinguere l'origin…
Investigations on standard pigments with multispectral and XRF analysis
2008
Integrated methodologies for qualitative and quantitative characterization of historical pigments
2014
Chemometric Tools to Point Out Benchmarks and Chromophores in Pigments through Spectroscopic Data Analyses
2021
Spectral preprocessing data and chemometric tools are analytical methods widely applied in several scientific contexts i.e., in archaeometric applications. A systematic classification of natural powdered pigments of organic and inorganic nature through Principal Component Analysis with a multi-instruments spectroscopic study is presented here. The methodology allows the access to elementary and molecular unique benchmarks to guide and speed up the identification of an unknown pigment and its recipe. This study is conducted on a set of 48 powdered pigments and tested on a real-case sample from the wall painting in S. Maria Delle Palate di Tusa (Messina, Italy). Four spectroscopic techniques …
Antioxidant activities of prickly pear ( Opuntia ficus indica) fruits and its betalains: betanin and indicaxanthin.
2004
Phytochemicals and phytomedicines are now an expanding research fields. A great number of active agents occurring in plants and herbs have been discovered, which is fundamental to find a rationale for the health effects of these herbs, in many cases used for centuries as traditional remedies. The knowledge of the mechanisms and molecular basis of their action is the final objective to understand the mode of action of the discovered principles. Studies on the bioactivity of cactus pear are very recent and results obtained so far, while exciting, now generate new questions. In vivo studies on healthy humans showed a strong protection of the body antioxidant system, and a marked reduction of p…
LU FMOF optometrijas un redzes zinātnes nodaļas un Latvijas optometristu un optiķu asociācijas konferenču referātu tēzes
2020
Tēzes no LU 78.starptautiskās zinātniskās konferences Cilvēka fizioloģijas un uztveres sēdes un LU Optometrijas un redzes zinātnes nodaļas un LOOA kopīgās klīniski praktiskās konferences Rīgā, 2020.gada 14., 16. februārī
Makulas pigmenta optisko blīvumu ietekmējošie faktori skolas vecuma bērniem
2019
Bakalaura darbs ir uzrakstīts latviešu valodā uz 37 lapaspusēm un satur 14 attēlus, 6 tabulas un 71 atsauci uz literatūras avotiem. Darba mērķis bija noskaidrot makulas pigmenta optisko blīvumu skolas vecuma bērniem Mārupes pamatskolā un tā saistību ar ķermeņa masas indeksu un citiem faktoriem. Pētījumā piedalījās 253 bērni vecumā no 7 līdz 14 gadiem (vidējais vecums 9 gadi), kuriem tika noteikts makulas pigmenta optiskais blīvums ar Macular Pigment Screener iekārtu, kas balstās uz hetereohromatisko flikera fotometriju. Bakalaura darbā netika pierādīta statistiski nozīmīga saistība starp makulas pigmenta optisko blīvumu un ķermeņa masas indeksu, dzimumu un varavīksnenes krāsu.
Preliminary Study of the Mural Paintings of Sotterra Church in Paola (Cosenza, Italy)
2022
A multi-analytical approach was employed to study wall paintings located in the Sotterra church at Paola, in the province of Cosenza, Italy. The site is an underground church (hence the name of Sotterra, which means “under the earth”) rediscovered in the second half of the 19th century, during the building works of the Madonna del Carmine church on the same area. This underground church preserves valuable mural paintings having different styles. The construction’s dating and overlapped modifications made until the site was abandoned is also debated. A wall painting, depicting “The Virgin” as part of the “Annunciation and the Archangel Gabriel” prese…
Pigment patterns in mutants affecting the biosynthesis of pteridines and xanthommatin in Drosophila melanogaster.
1986
Eye-color mutants of Drosophila melanogaster have been analyzed for their pigment content and related metabolites. Xanthommatin and dihydroxanthommatin (pigments causing brown eye color) were measured after selective extraction in acidified butanol. Pteridines (pigments causing red eye color) were quantitated after separation of 28 spots by thin-layer chromatography, most of which are pteridines and a few of which are fluorescent metabolites from the xanthommatin pathway. Pigment patterns have been studied in 45 loci. The pteridine pathway ramifies into two double branches giving rise to isoxanthopterin, “drosopterins,” and biopterin as final products. The regulatory relationship among the …
The use of botanical raw materials in hair dyeing
2021
Rynek kosmetyczny bogaty jest w produkty umożliwiające zmianę koloru włosów. Dostępne są trzy możliwości koloryzacji chemicznej zależne od czasu utrzymywania się docelowego koloru. Wśród nich wyróżnia się farbowanie krótkotrwałe, półtrwałe oraz długotrwałe. Przy użyciu składników syntetycznych możliwe jest uzyskanie pełnego przekroju kolorystycznego. Doniesienia o niepożądanych skutkach ubocznych farb chemicznych, zarówno dotyczących skóry głowy jak i struktury włosów przemawiają za powrotem naturalnych sposobów koloryzacji włosów, i za rozwojem tego kierunku. Celem opracowania było przybliżenie możliwości zastosowania surowców roślinnych celem koloryzacji włosów. Scharakteryzowano następuj…