A new glance on R2MGe6 (R = rare earth metal, M = another metal) compounds. An experimental and theoretical study of R2PdGe6germanides

The R2PdGe6series (R = rare earth metal) was structurally characterized, and the results achieved were extended for a comprehensive study on R2MGe6(M = another metal) compounds, employing symmetry-based structural rationalization and energy calculations. Directly synthesized R2PdGe6exists for almost all R-components (R = Y, La-Nd, Sm and Gd-Lu) and even if with La is probably metastable. Several single crystal X-ray analyses (R = Y, Ce, Pr, Nd, Er and Lu) indicated oS72-Ce2(Ga0.1Ge0.9)7as the correct structure. The alternative In-flux method, once optimized, produced three good quality R2PdGe6single crystals: La2PdGe6and Pr2PdGe6turned out to be mS36-La2AlGe6-type non-merohedrally twinned crystals and Yb2PdGe6is of oS72-Ce2(Ga0.1Ge0.9)7-type. The vacancy ordering phenomenon was considered as a possible cause of the symmetry reduction relations connecting the most frequently reported 2:1:6 structural models (oS18, oS72 and mS36) with the oS20-SmNiGe3aristotype. The detected twin formation is consistent with the symmetry relations, which are discussed even considering the validity of the different structural models. DFT total energy calculations were performed for R2PdGe6(R = Y and La) in the three abovementioned structural models, and for La2MGe6(M = Pt, Cu, Ag and Au) in the oS18 and oS72 modifications. The results indicate that the oS18-Ce2CuGe6structure, prevalently proposed in the literature, is associated with the highest energy and thus it is not likely to be realized in these series. The oS72 and mS36 polytypes are energetically equivalent, and small changes in the synthetic conditions could easily stabilize any of them, in agreement with experimental results obtained by direct and flux syntheses

The Binding Pocket at the Interface of Multimeric Telomere G-quadruplexes: Myth or Reality?

Human telomeric DNA with hundreds of repeats of the 5’-TTAGGG-3’ motif plays a crucial role in several biological processes. It folds into G-quadruplex (G4) structures and features a pocket at the interface of two contiguous G4 blocks. Up to now no structural NMR and crystallographic data are available for ligands interacting with contiguous G4s. Naphthalene diimide monomers and dyads were investigated as ligands of a dimeric G4 of human telomeric DNA comparing the results with those of the model monomeric G4. Time-resolved fluorescence, circular dichroism, isothermal titration calorimetry and molecular modeling were used to elucidate binding features. Ligand fluorescence lifetime and induced circular dichroism unveiled occupancy of the binding site at the interface. Thermodynamic parameters confirmed the hypothesis as they remarkably change for the dyad complexes of the monomeric and dimeric telomeric G4. The bi-functional ligand structure of the dyads is a fundamental requisite for binding at the G4 interface as only the dyads engage in complexes with 1 : 1 stoichiometry, lodging in the pocket at the interface and establishing multiple interactions with the DNA skeleton. In the absence of NMR and crystallographic data, our study affords important proofs of binding at the interface pocket and clues on the role played by the ligand structure

A naphthalene diimide dyad for fluorescence switch-on detection of G-quadruplexes

A non-fluorescent dimeric naphthalene diimide dye becomes red emitting upon G-quadruplex binding

Transabdominal ultrasonographic measurement of caudal vena cava to aorta derived ratios in clinically healthy neonatal foals

Background: Ultrasonographic measurement of the vena cava and aorta (Ao) diameters and their ratios have been suggested to be a reliable way of quantifying hypovolemia. Objective: To evaluate the feasibility and reliability of an ultrasonographic technique for measurement of Ao and caudal vena cava (CVC) and derived ratios using three different acoustic windows in a population of healthy neonatal foals. Correlation between Ao and CVC measurements and ratios and foals' age or bodyweight were also investigated. Methods: In 14 healthy foals aged less than 7 days, the diameters of the Ao and of the CVC in long and short axis were measured by two observers from images obtained using three different ultrasonographic imaging planes (left dorsal, left ventral and right views). The Ao and CVC cross-sectional area and the CVC/Ao diameter and area ratios were calculated. Image quality was subjectively assessed. Intraobserver and interobserver reliabilities for image quality scores and measurements were evaluated between the two observers. Simple linear regression models were used to identify correlations between the CVC/Ao measurements and ratios and the age and bodyweight of the foals. Results: The left ventral view showed the highest reliability. A correlation between bodyweight and the short axis measurement of the CVC was found (R2 = 0.385; p = 0.018). Age was positively correlated with the long axis of measurement of the CVC (R2 = 0.426; p = 0.011) and CVC/Ao diameter ratio (R2 = 0.625; p = 0.001). Conclusions: The left ventral view allows the Ao and CVC cross sections to be easily visualized and measured in neonatal foals in right lateral recumbency

Dyads of G-Quadruplex Ligands Triggering DNA Damage Response and Tumour Cell Growth Inhibition at Subnanomolar Concentration

Naphthalene diimide (NDI) dyads exhibiting a different substitution pattern and linker length have been synthesised and evaluated as G-quadruplex (G4) ligands, by investigating their cytotoxicity in selected cell lines. The dyads with the long C7 linker exhibit extremely low IC50 values, below 10\u2005nm, on different cancer cell lines. Contrary, the dyads with the shorter C4 linker were much less effective, with IC values increasing up to 1\u2005\u3bcm. Among the three dyads with the longest linker, small differences in the IC50 values emerge, suggesting that the linker length plays a more important role than the substitution pattern. We have further shown that the dyads are able to induce cellular DNA damage response, which is not limited to the telomeric regions and is likely the origin of their cytotoxicity. Both absorption titration and dynamic light scattering of the most cytotoxic dyads in the presence of hTel22 highlight their ability to induce effective G4 aggregation, acting as non-covalent cross-linking agents

Influence of vineyard inter-row management and clone on 'Sauvignon Blanc' performance in Friuli Venezia Giulia (north-eastern Italy)

The vineyard inter-row management affects grapevine vegetative and bunch health status, as well as yield and grape quality parameters. Several studies assessed that cover-cropped inter-row in place of soil tillage often reduced plant vigour and yield but positively contributed to vineyard ecosystem services and, to a lower extent, to grape quality. In 2013 and 2014, two inter-row management strategies, i.e. soil tillage and mowing of spontaneous cover crops, were compared in an organic vineyard in north-eastern Italy and cultivated with 'Sauvignon Blanc' (Vitis vinifera L.), clones R3 and 297. In particular, the effects of tillage and mowing treatments on grapevine vegetative and bunch health status, yield and grape quality were evaluated. The vegetative parameters were lower in the mowing treatment than in the tillage one and in clone R3 compared to 297. The incidence of Botrytis cinerea was higher in the tillage treatment than in the mowing one and in clone 297 compared to R3. A significant reduction of the yield and bunch weight was ascertained in the mowing treatment, and these parameters were higher for clone 297 compared to clone R3. Titratable acidity was significantly higher in the tillage treatment than in the mowing one and in clone 297 compared to R3. Moreover, hue of berry skin was qualitatively better in the tillage treatment than in the mowing one. In the pedo-climatic conditions of Friuli Venezia Giulia (north-eastern Italy), the management of the vineyard inter-row with spontaneous cover crops proved to be effective to manage grapevine vigour, reducing yield and improving quality of the grapes during maturation

The design of organic catalysis for epoxidation by hydrogen peroxide

The potential of various organic species to catalyze epoxidation of ethene by hydrogen peroxide is explored with B3LYP/6-31G* DFT calculations

Collezione di antichità di Palazzo Lancellotti ai Coronari: archeologia, architettura, restauro

la lingua del volume è in italiano e in ingles