University of Trás-os-Montes & Alto Douro

Given the potential of Carbon Dots and their wide applications, strategies for their immobilization are vital for the development of specific, stable and sensitive (bio)chemical analysis. In this review we start by demonstrating the most common and efficient immobilization procedures used in Cdots. Subsequently, we describe the Carbon dots-host nanocomposites synthesis, properties, and ultimately outline and revise the fields where they have been used by presenting applications in this field. The Carbon dots-host nanocomposites enhanced properties are also explored, namely: increase photoluminescence intensity and electron transfer rates, induce light absorption, bandgap tuning, abundant introduction of functional groups, lower toxicity and biocompatibility.

The enantioselective toxicity of 3,4-methylenedioxypyrovalerone (MDPV) remains unexplored in freshwater organisms. This study investigated the effects of MDPV racemate and its enantiomers in Daphnia magna using two approaches: (i) an 8-day sub-chronic assay focused on early development stages; and (ii) the standard 21-day reproduction assay. The sub-chronic assay tested two environmental concentrations (0.10 and 1.0 μg L^-1), for both racemate or individual enantiomers, and a higher sublethal concentration of 10 μg L^-1 for the racemate. Survival, morphophysiological, behavioural, reproductive, and biochemical responses were evaluated. The reproduction assay tested concentrations from 0.10 to 1.79 μg L^-1, and evaluated survival, body size, and reproductive effects. Sub-chronic exposure to 10 μg L^-1 (R,S)-MDPV decreased survival. MDPV racemate and its enantiomers changed morphophysiological parameters, except for body growth. In juveniles, the heart area increased with 0.10 μg L^-1 of (R)-MDPV whereas the heart size decreased with 0.10 and 1.0 μg L^-1 of (S)-MDPV. Enantioselective effects were observed in swimming behaviour: (S)-MDPV increased speed and (R)-MDPV increased active time. No effects were observed in biochemical (except in reactive oxygen species for (S)-MDPV) and early reproductive parameters. The reproduction assay revealed enhanced growth in all MDPV forms (except at 0.56 μg L^-1). A nonsignificant reduction in survival to the higher concentrations of (R)-MDPV was accompanied by reduced reproductive output (at 1.00 and 1.79 μg L^-1) and intrinsic rate of population increase (at 1.79 μg L^-1). Our findings suggest that, in general, (S)-MDPV triggers more severe sub-chronic effects, whereas (R)-MDPV is associated with harmful effects for longer time exposure.

Epithelial cell adhesion molecule (EpCAM) is a transmembrane glycoprotein, and its overexpression has been reported in various human epithelial cancers, namely in gastric cancer. This study evaluated the EpCAM immunohistochemical expression pattern in canine tissue samples: non-neoplastic gastric mucosa (n = 14) and gastric carcinoma (n = 31). EpCAM was consistently expressed in all cases of non-neoplastic gastric mucosa and in 96.8 % of gastric carcinomas, 64.5 % of which showed EpCAM overexpression. EpCAM overexpression was statistically more frequent in intestinal type carcinomas (100.0 %; p = 0.036) than in diffuse-type carcinomas (47.4 %), according to Lauren classification. No statistically significant differences in EpCAM expression were observed regarding sex, age, body weight, tumour location, tumour depth and histological type according to the human WHO classification. EpCAM overexpression was associated with previously studied markers of canine gastric cancer, namely E-cadherin, TFF1, vimentin and Ki-67 and a significantly association between EpCAM overexpression and high Ki-67 proliferative index in neoplastic cells of gastric carcinomas was observed (Kappa=0.358; p = 0.042). Our results demonstrate that EpCAM is expressed in canine gastric tissues and overexpressed in gastric carcinomas, being potentially involved in the gastric carcinogenesis in dogs.