Design and synthesis of potential β-sheet nucleators via Suzuki coupling reaction

Three series of compounds characterized by biphenylic structure were synthesized in order to develop new scaffolds able to induce β-sheet folding in the peptides. Microwave flash heating was used in order to shorten reaction times and to enhance the obtained yields. Simulated annealing molecular dynamics simulations demonstrated that some of the compounds were capable of adopting a 15-membered intramolecularly hydrogen-bonded conformation, which supports an antiparallel β-sheet structure.     

Deduzione variazionale delle equazioni gravitazionali spinoriali

Sunto Si deducono da un principio variazionale le equazioni gravitazionali per gli spazi vuoti, in forma spinoriale, valendosi dell’azione gravitazionale einsteiniana e assumendo come variabili base le componenti dello spin-tensore fondamentale. Per particolari variazioni, si ottengono le identità contratte del Bianchi, in forma spinoriale.

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Summary In this paper, gravitational field equations for empty-space, in spinor form, are derived from a variational principle by making use of the einsteinian gravitational Action and by assuming as basic variables describing the field the components of the fundamental spin-tensor. With an appropriate variation, the contracted Bianchi identities, in spinor form, are deduced.

     

Boundary value problems and Mayer-Vietoris sequence

Milan Journal of Mathematics - We define formally non characteristic hypersurfaces for a complex of differential operators and we establish a Mayer-Vietoris sequence. We give applications to...     

Stereochemical aspects of the asymmetric synthesis of chiral α,β-dihydroxy phosphonates. Synthesis of α,β-dihydroxy phosphonic acids

Stereocontrol in the asymmetric phosphonylation of aldehydes via organophosphorous esters has been obtained starting from chiral aldehydes. The nature of the O-protecting group is crucial to obtain, in terms of diastereoselectivity and chemical yields, the best results. An ab initio molecular orbital study on 2-silyloxy propanal and MM2 studies on 2-alkoxy propanal show the existence of stable cyclic and acyclic conformers, which are presumably responsible for the high syn diastereoselectivity observed in the addition of non-metal carrying phosphites.     

Synthesis and structural,magnetic and electrochemical characterization of PtCo nanoparticles prepared by water-in-oil microemulsion

PtCo nanoparticles with homogeneous size (around 3–4 nm) have been synthesized in a water-in-oil microemulsion of water/polyethylenglycol–dodecylether (BRIJ^®30)/n-heptane. X-ray diffraction study revealed the formation of a cubic phase with a gradual decrease of the cell parameter with increasing cobalt incorporation in the crystalline lattice of platinum. In relation to their magnetic properties, the PtCo nanoparticles present a superparamagnetic behaviour even after annealing, although higher permeability was induced by the thermal treatment. Finally, the electrocatalytic activity of the particles towards oxalic acid oxidation in H₂SO₄ was evaluated. The Pt74Co26 nanoparticles showed the highest reactivity for this reaction.     

α-Synuclein overexpression increases dopamine toxicity in BE(2)-M17 cells

Background  

Oxidative stress has been proposed to be involved in the pathogenesis of Parkinson's disease (PD). A plausible source of oxidative stress in nigral dopaminergic neurons is the redox reactions that specifically involve dopamine and produce various toxic molecules, i.e., free radicals and quinone species. α-Synuclein, a protein found in Lewy bodies characteristic of PD, is also thought to be involved in the pathogenesis of PD and point mutations and multiplications in the gene coding for α-synuclein have been found in familial forms of PD.