Search results for "PIGMENT"

Voltammetric analysis of iron oxide pigments

2002

Eighteen earthy and four pure synthetic pigments containing alpha-Fe2O3 (hematite), alpha-FeOOH (goethite) and poorly crystalline Fe and Mn oxide species were analyzed by voltammetry of microparticles. Three natural samples were subjected to an interlaboratory test to evaluate the reproducibility of the voltammetric peak potentials and peak shapes. The results confirmed that linear-sweep voltammetry is able to distinguish between poorly crystalline, ferrihydrite-like oxides and well-crystalline hematite and goethite and to detect XRD-amorphous Mn(III,IV) oxides via the peak occurrence. Voltammetry is further able to distinguish between pigments containing well-crystalline goethite (accordin…

Identification of Earth Pigments by Applying Hierarchical Cluster Analysis to Solid State Voltammetry. Application to Severely Damaged Frescoes

2007

Multivariate chemometric methods are applied for identifying earth pigments from square-wave voltammetric measurements performed at pigment-modified paraffin-impregnated graphite electrodes allowing for a separation between hematite-based earths, French ochres, Spanish ochres, siennas, umbers and green earths. This methodology is applied to the identification of the pigments in samples from the ceiling frescoes of Antonio Palomino (dated 1707) in the vaulted nave of the Sant Joan del Mercat church in Valencia (Spain). These frescoes suffered considerable damage by fire during the Spanish Civil War in 1936, resulting in severe chemical and chromatic alterations. Electrochemical data, support…

Color Stabilization of Apulian Red Wines through the Sequential Inoculation of Starmerella bacillaris and Saccharomyces cerevisiae

2021

Mixed fermentation using Starmerella bacillaris and Saccharomyces cerevisiae has gained attention in recent years due to their ability to modulate the qualitative parameters of enological interest, such as the color intensity and stability of wine. In this study, three of the most important red Apulian varieties were fermented through two pure inoculations of Saccharomyces cerevisiae strains or the sequential inoculation of Saccharomyces cerevisiae after 48 h from Starmerella bacillaris. The evolution of anthocyanin profiles and chromatic characteristics were determined in the produced wines at draining off and after 18 months of bottle aging in order to assess the impact of the different f…

Activation of a caspase-3-independent mode of cell death associated with lysosomal destabilization in cultured human retinal pigment epithelial cells…

2008

International audience; Purpose: To characterize the possible cytotoxic effects of oxysterols (7-hydroxycholesterol (7-OH), 25-hydroxycholesterol (25-OH)) in human retinal pigment epithelial cells (ARPE-19) and to detail the relationships between some of these effects. Methods: ARPE-19 cells were treated with 7-OH and 25-OH. Cell viability was measured with the MTT assay. Membrane permeability, mitochondrial potential, and lysosomal integrity were measured by flow cytometry with propidium iodide, DiOC6(3), and acridine orange, respectively. Cell death was characterized by staining with Hoechst 33342, transmission electron microscopy, and analysis of the DNA fragmentation pattern. Caspase ac…

Screening of the USH1G gene among Spanish patients with Usher syndrome. Lack of mutations and evidence of a minor role in the pathogenesis of the syn…

2007

The Usher syndrome (USH) is an autosomal recessive hereditary disorder characterized by the association of sensorineural hearing loss, retinitis pigmentosa (RP) and, in some cases, vestibular dysfunction. The USH1G gene, encoding SANS, has been found to cause both Usher syndrome type I and atypical Usher syndrome. 109 Spanish unrelated patients suffering from Usher syndrome type I, type II, type III and unclassified Usher syndrome were screened for mutations in this gene, but only eight different changes without a clear pathogenic effect have been detected. Based on these results as well as previous studies in other populations where mutational analysis of this gene has been carried out, on…

Atypical Phacomatosis Pigmentokeratotica as the Expression of a Mosaic RASopathy With the BRAF-Glu586Lys Mutation

2016

Progressive depigmentation of a melanocytic lesion: a dermoscopic challenge for melanoma diagnosis.

2013

I Difetti Congeniti Della Pigmentazione

2008

Interaction of Human Phagocytes with Pigmentless Aspergillus Conidia

2000

ABSTRACT A defect in the pksP gene of Aspergillus fumigatus is associated with the loss of conidial pigmentation, a profound change of the conidial surface structure, and reduced virulence. The structural change of the conidial surface structure was not observed in similar A. nidulans wA mutants. Our data indicate that the pigment of both species is important for scavenging reactive oxygen species and for protection of conidia against oxidative damage.

Indocyanine Green Angiography in Congenital Hypertrophy of the Retinal Pigment Epithelium

2017

PURPOSE To report a case of congenital hypertrophy of the retinal pigment epithelium followed up for 7 years showing features not previously reported. METHODS A complete fundus examination including fluorescein angiography was performed at first examination and at follow-up. RESULTS The area of congenital hypertrophy of the retinal pigment epithelium presented morphologic changes, showing enlargement of the lesion on one side associated with partial regression on another side. In addition, the indocyanine green angiography findings revealed that this test was more useful than fluorescein angiography to delineate the real boundaries of the lesion and disclosed hypofluorescent areas inside th…