Littérature scientifique sur le sujet « Contrasti cromatici »

Objective. The aim of this study is to analyze the variation of color among the maxillary anterior teeth. Additionally, this variation has been correlated with the age of the patients. Means and method. One examiner, free of any visual color deficiencies, has studied the chromatic behavior within the maxillary anterior dental group (13-23) for 30 subjects with ages between 23 and 34. With the help of the Vita Easy Shade (Vita Zahnfabrik – Germany), CIEL*a*b* chromatic parameters have been recorded for each tooth. Chromatic differences have been calculated for each set of adjacent teeth. The stated null hypothesis „There is no statistically relevant correlation between patients age and color variation among the maxillary anterior dental group“ was evaluated with the help of the Spearman/Pearson tests. Additional linear regression calculations have been made in order to estimate the color variation among anterior maxillary teeth in relation to age. Within the age limits of the study group, the estimated color variation has been calculated for the minimum age (23), maximum age (34) and medium age (28.5). Results. The correlations show that age is significantly correlated to the variation in dental color for the pairs 13/12, 12/11 and 22/23 (p<0.05). For the remaining pairs of teeth (11/21 and 21/22) the correlation between age and color variation is not relevant. Within the limits of this study, a tendency for chromatic uniformity has been noticed for 12/11, 11/21, 21/22, the differences becoming imperceptible to the human eye (∆E<2 ) after the age of 33, whereas the canines start to chromatically differentiate from the neighboring incisors around the age of 14-16, the contrast becoming more intense with age. Conclusions. Color is not uniformly distributed among the anterior maxillary teeth, and the chromatic variation is related to patients age. Therefore while restoring the maxillary arch with dentures (complete or partial), the sets of artificial teeth used should respect the color distribution in relation to the patient’s age.

The objective of this research was to evaluate the effect of sperm on chromatin stability and its relationship with the membrane integrity structural – physiological and the rate of fertilization of female sheep. Ejaculates of sperm (2 × 109 sperm·mL-1) with 70% of motility were collected using an artificial vagina (n=5, 2 years old. For this, each ram was served with fifteen female sheep (n=75), generating thus five different Groups (A, B, C, D, and E). A control Group also was considered. Sperm nuclear chromatin stability (NCS) was evaluated using the Borate Buffer (BB), Sodium Dodecyl Sulfate (SDS), and the mixture of Ethylenediaminetetraacetic acid (EDTA) + SDS. The fertilization rate was evaluated after 16-18 hours post sperm injection. Sperm concentration showed a significant difference (P<0.05) between Groups. In Contrast, seminal volume, and sperm motility do not show a significant difference (P>0.05). A high correlation (r2=0.52) was observed between morphology and motility, and the fertilization rate was 74.6% (n=56). It was concluded in general that techniques to evaluate nuclear condensation values do have a high likelihood to give a diagnosis about the future potential of sperm populations in Junín ram.

El tumor desmoplásico de células pequeñas y redondas (TDCPR) es una neoplasia maligna rara, con curso clínico agresivo y mortalidad elevada. Se presenta el caso de un hombre de 21 años de edad, quien consultó por dolor abdominal de intensidad moderada, irradiado al flanco derecho, fiebre y pérdida de peso. En tomografía abdominal con medio de contraste se documentó una gran masa intraperitoneal con áreas de necrosis central y extensión a la pelvis, además de lesiones hepáticas de aspecto neoplásico secundario. El diagnóstico se confirmó mediante biopsia percutánea guiada por ultrasonido, que mostró extensa infiltración por tumor maligno, constituido por células con núcleos vesiculosos de cromatina clara, citoplasma eosinófilo e inmunohistoquímica compatible con dicho tumor. En este artículo se hace una confrontación del caso con los hallazgos descritos en otras series publicadas en la literatura y una revisión clínica del tema.

In this essay I aim to draw close to an exceptional case study in American modernist art theory: Clement Greenberg’s reinterpretation of Flemish and Dutch painting. I will focus on it in connection with the Greenbergian vision of modernism as a whole. Firstly, I will make a genealogy of the “Flemish turn” in the history of aesthetics, by analyzing the key moments (Winckelmann, Hegel, Baudelaire) in which the so-called Northern Primitives have served to frame modern painting, in contrast to Southern classic Renaissance. Then, I will concentrate on Greenberg’s use of this heritage, by comparing his linking Flemish colour with photography to Svetlana Alpers’ notion of “art of describing”. It will emerge that an original interaction between colour and photography is given, that is suitable both to the notion of realism and to its modernist acceptance.