Polimeri conduttori e metallopolimeri redox

Il nostro gruppo di ricerca è da anni attivo nella sintesi e caratterizzazione elettrochimica di polimeri conduttori a base tiofenica. In particolare la nostra attenzione è rivolta verso materiali costituiti da un backbone di tipo tertiofenico, che consente la polimerizzazione nelle posizioni 2 e 5, e da unità chelanti all’azoto, (terpiridine o fenantroline), che possono consentire la coordinazione con metalli di transizione all’interno del polimero ed incrementarne ulteriormente le proprietà conduttive

Genetic lineage tracing reveals poor angiogenic potential of cardiac endothelial cells.

Abstract Aims Cardiac ischaemia does not elicit an efficient angiogenic response. Indeed, lack of surgical revascularization upon myocardial infarction results in cardiomyocyte death, scarring, and loss of contractile function. Clinical trials aimed at inducing therapeutic revascularization through the delivery of pro-angiogenic molecules after cardiac ischaemia have invariably failed, suggesting that endothelial cells in the heart cannot mount an efficient angiogenic response. To understand why the heart is a poorly angiogenic environment, here we compare the angiogenic response of the cardiac and skeletal muscle using a lineage tracing approach to genetically label sprouting endothelial cells. Methods and results We observed that overexpression of the vascular endothelial growth factor in the skeletal muscle potently stimulated angiogenesis, resulting in the formation of a massive number of new capillaries and arterioles. In contrast, response to the same dose of the same factor in the heart was blunted and consisted in a modest increase in the number of new arterioles. By using Apelin-CreER mice to genetically label sprouting endothelial cells we observed that different pro-angiogenic stimuli activated Apelin expression in both muscle types to a similar extent, however, only in the skeletal muscle, these cells were able to sprout, form elongated vascular tubes activating Notch signalling, and became incorporated into arteries. In the heart, Apelin-positive cells transiently persisted and failed to give rise to new vessels. When we implanted cancer cells in different organs, the abortive angiogenic response in the heart resulted in a reduced expansion of the tumour mass. Conclusion Our genetic lineage tracing indicates that cardiac endothelial cells activate Apelin expression in response to pro-angiogenic stimuli but, different from those of the skeletal muscle, fail to proliferate and form mature and structured vessels. The poor angiogenic potential of the heart is associated with reduced tumour angiogenesis and growth of cancer cells

IGHV gene mutational status and 17p deletion are independent molecular predictors in a comprehensive clinical-biological prognostic model for overall survival prediction in chronic lymphocytic leukemia

Prognostic index for survival estimation by clinical-demographic variables were previously proposed in chronic lymphocytic leukemia (CLL) patients. Our objective was to test in a large retrospective cohort of CLL patients the prognostic power of biological and clinical-demographic variable in a comprehensive multivariate model. A new prognostic index was proposed

Modelling spatial uncertainty of soil erodibility factor using joint stochastic simulation

Soil erosion varies greatly over space and is commonly estimated using the revised universal soil loss equation (RUSLE). Neglecting information about estimation uncertainty, however, may lead to improper decision-making. One geostatistical approach to spatial analysis is joint stochastic simulation, which draws alternative, equally probable, joint realizations of a regionalized variable. Differences between the realizations provide a measure of spatial uncertainty and allow us to carry out an error propagation analysis. The objective of this paper was to assess spatial uncertainty of a soil erodibility factor (K) model resulting from the uncertainties in the input parameters (texture and organic matter). The 500 km2 study area was located in central-eastern Sardinia (Italy) and 152 samples were collected. A Monte Carlo analysis was performed where spatial cross-correlation information through joint turning bands simulation was incorporated. A linear coregionalization model was fitted to all direct and cross-variograms of the input variables, which included three different structures: a nugget effect, a spherical structure with a shorter range (3500 m) and a spherical structure with a longer range (10 000 m). The K factor was then estimated for each set of the 500 joint realizations of the input variables, and the ensemble of the model outputs was used to infer the soil erodibility probability distribution function. This approach permitted delineation of the areas characterized by greater uncertainty, to improve supplementary sampling strategies and K value predictions

Chiral complexes of Rh^I containing binaphthalene-core P,S-heterobidentate ligands: synthesis, characterization, and catalytic activity in asymmetric hydrogenation of α,β-unsaturated acids and esters

The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4− [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b)] have been prepared from [Rh(NBD)(THF)2]+BF4− by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60% ee have been recorded

Oligo-thiophene tethered 1,10-phenanthroline as N-chelating moiety: electrochemical and optical characterization of the π-conjugated molecule and of the relevant conducting polymer and metallopolymers

The synthesis and characterization of a new highly conjugated molecule, 4-(2,2':50,200-terthien-3'-ethynyl)- 1,10-phenanthroline (TAF4) is reported. The new compound features an expanded π-conjugation as compared with the analogue 2,20:60,200-terpyridine derivative (4'-(2,2':50,200-terthien-3'-ethynyl)- 2,2':60,200-terpyridine) we have recently reported. The electrochemical polymerization of TAF4 allows to obtain the corresponding conducting polymer PTAF4. Electrochemical and spectroscopic characterization were performed on both the original tether TAF4 and the polymer, and the results are compared with related structures bearing different spacers and nitrogen substituents. PTAF4 shows a remarkable lowering of band gap value that is consequent on the nature both of the spacer and of the substituent on the terthiophene fragment. Furthermore, the synthesis and characterization of the Ru(II) complex, [Ru(TAF4)3][PF6]2, and of the corresponding metallopolymers, are reported.</br