642 research outputs found
Il restauro dei dipinti "olio su tela"
none3Il testo condensa la lunga ed eterogenea attivitĂ didattica relativa allâargomento, innanzitutto quella svolta dai tre autori, a vario titolo, presso lâUniversitĂ di Bologna. Molte affermazioni, cosâ come tutta lâiconografia, derivano direttamente dalla poliedrica e trentennale attivitĂ dello âStudio di Restauro G.M.Costaniniâ. nel tempo, cambiano i materiali e le tecniche di restauro, ma ciò che dovrebbe rimanere saldo per chi è coinvolto in problemi di restauro è la capacitĂ di una lettura sistematica dellâopera dâarte e del suo stato di conservazione e la possibilitĂ di elaborare o valutare gli interventi adatti per rallentare lâinevitabile degrado dei materiali. Per queste ragioni, tutto quello che qui riguarda direttamente i dipinti olio su tela, nella sua articolazione e sistemazione, risulta certamente proficuo anche nellâapproccio al restauro di altre categorie di opere dâarte.noneCostantini G.M.; Costato Costantini R.; Fiori C.Costantini G.M.; Costato Costantini R.; Fiori C
Molecular cloning, differential expression and 3D structural analysis of the MHC class-II β chain from sea bass (Dicentrarchus labrax L.)
The major histocompatibility complex class I and II molecules (MHC-I and MHC-II) play a pivotal role in vertebrate immune
response to antigenic peptides. In this paper we report the cloning and sequencing of the MHC class II b chain from sea bass (Dicentrarchus
labrax L.). The six obtained cDNA sequences (designated as Dila-DAB) code for 250 amino acids, with a predicted 21
amino acid signal peptide and contain a 28 bp 50-UTR and a 478 bp 30-UTR. A multiple alignment of the predicted translation of the
Dila-DAB sequences was assembled together with other fish and mammalian sequences and it showed the conservation of most
amino acid residues characteristic of the MHC class II b chain structure. The highest basal Dila-DAB expression was found in gills,
followed by gut and thymus, lower mRNA levels were found in spleen, peripheral blood leucocytes (PBL) and liver. Stimulation of
head kidney leukocytes with LPS for 4 h showed very little difference in the Dila-DAB expression, but after 24 h the Dila-DAB
level decreased to a large extent and the difference was statistically significant. Stimulation of head kidney leukocytes with different
concentrations of rIL-1b (ranging from 0 to 100 ng/ml) resulted in a dose-dependent reduction of the Dila-DAB expression. Moreover,
two 3D Dila-DAB*0101 homology models were obtained based on crystallographic mouse MHC-II structures complexed
with D10 T-cell antigen receptor or human CD4; features and differences between the models were evaluated and discussed. Taken
together these results are of interest as MHC-II structure and function, molecular polymorphism and differential gene expression
are in correlation with disease resistance to virus and bacteria in teleost fish.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com/This work was supported by the European Commission within the project IMAQUANIM (EC contract number
FOOD-CT-2005-007103)
CD4 homologue in sea bass (Dicentrarchus labrax): molecular characterization and structural analysis
CD4 is a transmembrane glycoprotein fundamental for cell-mediated immunity. Its action as a T cell coreceptor
increases the avidity of association between a T cell and an antigen-presenting cell by interacting
with portions of the complex between MHC class II and TR molecules. In this paper we report the cDNA
cloning, expression and structural analysis of a CD4 homologue from sea bass (Dicentrarchus labrax). The
sea bass CD4 cDNA consists of 2071 bp that translates in one reading frame to give the entire molecule
containing 480 amino acids. The analysis of the sequence shows the presence of four putative Ig-like
domains and that some fundamental structural features, like a disulphide bond in domain D2 and the CXC
signalling motif in the cytoplasmic tail, are conserved from sea bass to mammals. Real-time PCR analysis
showed that very high levels of CD4 mRNA transcripts are present in thymus, followed by gut and gills. In
vitro stimulation of head kidney leukocytes with LPS and PHA-L gave an increase of CD4 mRNA levels after
4 h and a decrease after 24 h. Homology modelling has been applied to create a 3D model of sea bass CD4
and to investigate its interaction with sea bass MHC-II. The analysis of the 3D complex between sea bass
CD4 and sea bass MHC-II suggests that the absence of a disulfide bond in the CD4 D1 domain could make
this molecule more flexible, inducing a different conformation and affecting the binding and the way of
interaction between CD4 and MHC-II. Our results will add new insights into the sea bass T cell immune
responses and will help in the identification of T cell subsets in teleost fishes to better understand the
evolution of cell-mediated immunity from fish to mammals.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com
Characterizing the tumor microenvironment in rare renal cancer histological types
The tumor microenvironment (TME), including immune cells, cancer-associated fibroblasts, endothelial cells, adjacent normal cells, and others, plays a crucial role in influencing tumor behavior and progression. Here, we characterized the TME in 83 primary renal tumors and matched metastatic or recurrence tissue samples (n =â15) from papillary renal cell carcinoma (pRCC) types 1 (n =â20) and 2 (n =â49), collecting duct carcinomas (CDC; n =â14), and high-grade urothelial carcinomas (HGUC; n =â5). We investigated 10 different markers of immune infiltration, vasculature, cell proliferation, and epithelial-to-mesenchymal transition by using machine learning image analysis in conjunction with immunohistochemistry. Marker expression was compared by Mann-Whitney and Kruskal-Wallis tests and correlations across markers using Spearman's rank correlation coefficient. Multivariable Poisson regression analysis was used to compare marker expression between histological types, while accounting for variation in tissue size. Several immune markers showed different rates of expression across histological types of renal carcinoma. Using pRCC1 as reference, the incidence rate ratio (IRR) of CD3+ T cells (IRR [95% confidence interval, CI] = 2.48 [1.53-4.01]) and CD20+ B cells (IRR [95% CI] = 4.38 [1.22-5.58]) was statistically significantly higher in CDC. In contrast, CD68+ macrophages predominated in pRCC1 (IRR [95% CI] = 2.35 [1.42-3.9]). Spatial analysis revealed CD3+ T-cell and CD20+ B-cell expressions in CDC to be higher at the proximal (p <â0.0001) and distal (p <â0.0001) tumor periphery than within the central tumor core. In contrast, expression of CD68+ macrophages in pRCC2 was higher in the tumor center compared to the proximal (p =â0.0451) tumor periphery and pRCC1 showed a distance-dependent reduction, from the central tumor, in CD68+ macrophages with the lowest expression of CD68 marker at the distal tumor periphery (p =â0.004). This study provides novel insights into the TME of rare kidney cancer types, which are often understudied. Our findings of differences in marker expression and localization by histological subtype could have implications for tumor progression and response to immunotherapies or other targeted therapies
Antioxidant Defenses Predict Long-Term Survival in a Passerine Bird
Normal and pathological processes entail the production of oxidative substances that can damage biological molecules and harm physiological functions. Organisms have evolved complex mechanisms of antioxidant defense, and any imbalance between oxidative challenge and antioxidant protection can depress fitness components and accelerate senescence. While the role of oxidative stress in pathogenesis and aging has been studied intensively in humans and model animal species under laboratory conditions, there is a dearth of knowledge on its role in shaping life-histories of animals under natural selection regimes. Yet, given the pervasive nature and likely fitness consequences of oxidative damage, it can be expected that the need to secure efficient antioxidant protection is powerful in molding the evolutionary ecology of animals. Here, we test whether overall antioxidant defense varies with age and predicts long-term survival, using a wild population of a migratory passerine bird, the barn swallow (Hirundo rustica), as a model.Plasma antioxidant capacity (AOC) of breeding individuals was measured using standard protocols and annual survival was monitored over five years (2006-2010) on a large sample of selection episodes. AOC did not covary with age in longitudinal analyses after discounting the effect of selection. AOC positively predicted annual survival independently of sex. Individuals were highly consistent in their relative levels of AOC, implying the existence of additive genetic variance and/or environmental (including early maternal) components consistently acting through their lives.Using longitudinal data we showed that high levels of antioxidant protection positively predict long-term survival in a wild animal population. Present results are therefore novel in disclosing a role for antioxidant protection in determining survival under natural conditions, strongly demanding for more longitudinal eco-physiological studies of life-histories in relation to oxidative stress in wild populations
Ethnic Minorities Rewarded: Ethnostratification on the Wage Market in Belgium
Several previous researches have confirmed the hypothesis of ethnostratification, which holds that the labour market is divided into different ethnic layers. While people of a European origin are over-represented in the top layers (the primary market), people with non-European roots and/or nationalities are more concentrated in bottom layers (the secondary market). Relative to the primary market, this secondary market is characterized by a higher chance of unemployment, lower wages, poorer working conditions and greater job insecurity. This paper deals with a very important condition of work: the wage. Does origin have an impact on the level of wage? We make a distinction between nine origin groups: Belgians, North en West Europeans, South Europeans (from Greece, Spain, Portugal), Italians, East Europeans, Moroccans, Turks, Sub Sahara Africans and Asians. The first part of this article briefly describes the database used for the analyses and presents a few general figures for the total Belgian population. In the second part we examine the impact of origin on wage levels. For each origin group we will give an overview of the average daily wages and the partition over the wage classes. For the weaker populations, gender and age are taken into account. Finally, by means of a regression analysis, we will examine the influence of origin while controlling a few other variables that may influence the wage level
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