Search results for "viol"
showing 10 items of 2848 documents
Spectroelectrochemistry of cytochrome c and azurin immobilized in nanoporous antimony-doped tin oxide
2011
Stable immobilization of two redox proteins, cytochrome c and azurin, in a thin film of highly mesoporous antimony-doped tin oxide is demonstrated via UV-vis spectroscopic and electrochemical investigation.
Effect of Stevia rebaudiana addition on bioaccessibility of bioactive compounds and antioxidant activity of beverages based on exotic fruits mixed wi…
2015
In order to determine the impact of Stevia rebaudiana (SR) addition on bioactive compounds bioaccessibility of a new developed functional beverage based on exotic fruits (mango juice, papaya juice and acai) mixed with orange juice and oat, an in vitro gastrointestinal digestion was performed. Ascorbic acid, total carotenoids, total phenolics, total anthocyanins, total antioxidant capacity and steviol glycosides were evaluated before and after a simulated gastrointestinal digestion. Salivary and gastric digestion had no substantial effect on any of the major phenolic compounds, ascorbic acid, total antioxidant capacity and steviol glycosides, whereas carotenoids and anthocyanins diminished s…
Synthesis and evaluation of diverse thio avarol derivatives as potential UVB photoprotective candidates.
2007
Semisynthesis of 13 new thio avarol derivatives (4-16) and in vitro evaluation on the photodamage response induced by UVB irradiation are described. Their ability to inhibit NF-kappaB activation and TNF-alpha generation in HaCaT cells as well as their antioxidant capacity in human neutrophils has also been studied. Among them we have identified two monophenyl thio avarol derivatives (4-5) lacking cytotoxicity which can be considered promising UVB photoprotective agents through the potent inhibition of NF-kappaB activation with a mild antioxidant pharmacological profile.
Nitic oxide promotes strong cytotoxicity of phenolic compounds against escherichia coli. The influence of antioxidant defenses
2003
[EN] The induction of mutagenic and cytotoxic effects by simple phenolics, including catechol (CAT), 3,4dihydroxyphenylacetic acid (DOPAC), hydroquinone (HQ), and 2,5-dihydroxyphenylacetic (homogentisic) acid (HGA), appears to occur through an oxidative mechanism based on the ability of these compounds to undergo autoxidation, leading to quinone formation with the production of reactive oxygen species. This is supported by the detection of such adverse effects in plate assays using Escherichia coli tester strains deficient in the OxyR function, but not in OxyR(+) strains. The OxyR protein is a redox-sensitive regulator of genes encoding antioxidant enzymes including catalase and alkyl hydro…
DNA replication arrest in response to genotoxic stress provokes early activation of stress-activated protein kinases (SAPK/JNK).
2009
Abstract The impact of DNA damage-induced replication blockage for early activation of stress kinases [stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK)] is largely unknown. Here, we show that induction of dual phosphorylation of SAPK/JNK by the DNA polymerase inhibitor aphidicolin was not ameliorated by additional exposure to ultraviolet (UV) light, indicating that overlapping mechanisms participate in signaling to SAPK/JNK triggered by both agents. UV-induced DNA replication blockage, cyclobutane pyrimidine dimer formation and DNA strand break induction coincided with SAPK/JNK phosphorylation at early (≤ 30 min) but not late (≥ 2 h) time points after exposure. Genotoxin…
Symbiosis between photoactive nanoparticles and their organic ligands.
2013
Photoactive spherical metal and semiconductor nanoparticles (NPs) are smart systems that exhibit unique properties, such as a high surface-to-volume ratio, a broad absorption spectrum and size-dependent properties. They are capped with a considerable number of ligands required to give rise to stable organic and aqueous NP colloidal solutions. In addition, the ligands can also be used to introduce functionality at the NP periphery. In this case, the NP could act as a 3D-scaffold, which would make a high local concentration of a functional moiety at the NP periphery possible, moreover, the photophysical properties of the NP could be tuned. The combined action of the organic capping and the in…
Solubilization control by redox-switching of polysoaps
2008
Reversible changes in the self-organization of polysoaps may be induced by controlling their charge numbers via covalently bound redox moieties. This is illustrated with two viologen polysoaps, which in response to an electrochemical stimulus, change their solubility and aggregation in water, leading from homogeneously dissolved and aggregated molecules to collapsed ones and vice verse. Using the electrochemical quartz crystal microbalance (EQCM), it could be shown that the reversibility of this process is better than 95% in 16 cycles.
VIOLURATO COMPLEXES OF Cr(III). SYNTHESIS AND CHARACTERIZATION. PROTONATION-DEPROTONATION EQUILIBRIA OF THE COORDINATED LIGANDS. EVIDENCE OF THE COOR…
1982
Abstract The formation of violurato complexes of Cr(III) has been studied in aqueous solution. Two compounds, [Cr(H2V)3].5H2O and Na[Cr(H2V)2(OH)2].4H2O have been synthesized and characterized. [Cr(H2V)3] behaves in aqueous solution as a triprotic acid but it can also add a proton yielding [Cr(H2V)2(H3V)]+. The acidity constants of this species have been determined: pKa1 =3.32, pKa2 =4.25, pKa3 =4.83 and pKa4 =6.99 (25°C, 0.1 M NaC1O4). [Cr(H2V)2(OH)2]− undergoes a deprotonation of the two H2V− ligands and a protonation of the hydroxo ligands. The acidity constants of [Cr(H2V)2(H2O)2]+ have been also determined: pKa1 =3.5, pKa2 =4.6, pKa3 =7.1 and pKa4 =9.2 (25°C, 0.1 M NaC1O4). The coordin…
An execution in medieval Sicily: Computerised tomography scan analysis and 3D reconstruction of an ancient forensic context
2019
The bioarchaeological and forensic approach is increasingly applied in the study of funerary contexts in archaeology. Here, we present a case of an atypical medieval burial recently discovered in Piazza Armerina (Sicily), in which the integrated use of traditional bioarchaeological and forensic anthropology methods was crucial. The skeleton was lying in a prone position and was characterised by a peculiar injury pattern. We recorded six clear stab wound marks on the posterior surface of the sternum. The use of computerised tomography scan and 3D modelling techniques has made it possible to obtain a reliable reconstruction of the cause and modality of death, pointing to the execution of the …
Un caso limite di persuasione. Strategie argomentative in Metafisica Gamma
2014
A partire dall’analisi del IV libro della Metafisica di Aristotele, l’articolo si propone di fornire alcuni spunti di riflessione sul funzionamento dei processi persuasivi nella prospettiva aristotelica. La difesa del principio di non contraddizione, infatti, si presenta come un caso di studio estremamente interessante per chi voglia studiare da una parte la relazione tra persuasione, evidenza e dimostrazione e, dall’altra, più in generale, il ruolo della persuasione nell’antropologia aristotelica.