Anna Maria Cucolo

Ferroelectric co-crystalline polymers

Apolar syndiotactic polystyrene (s-PS) can easily form a stable clathrate co-crystalline phase with highly polar 4-nitroaniline molecules. The ferroelectric response of thin films containing the s-PS/4-nitroaniline clathrate phase has been investigated by scanning piezoresponse force microscopy (SPFM) and compared with the response of a poly(vinylidene-fluoride-trifluoroethylene) P(VDF-TrFE) copolymer film. Measurements show that ferroelectric polymer materials can be obtained by crystalline phases whose polarity is given by low-molecular-mass guest molecules rather than by polymer chain polarity. Moreover, as for P(VDF-TrFE), nanoimprinting processes can be applied to these materials by using the SPFM technique but, in the absence of external fields, the SPFM images are lost through an exponential intensity decay.

Aggregation of Aß(25-35) on DOPC and DOPC/DHA Bilayers: An Atomic Force Microscopy Study

β amyloid peptide plays an important role in both the manifestation and progression of Alzheimer disease. It has a tendency to aggregate, forming low-molecular weight soluble oligomers, higher-molecular weight protofibrillar oligomers and insoluble fibrils. The relative importance of these single oligomeric-polymeric species, in relation to the morbidity of the disease, is currently being debated. Here we present an Atomic Force Microscopy (AFM) study of Aβ(25–35) aggregation on hydrophobic dioleoylphosphatidylcholine (DOPC) and DOPC/docosahexaenoic 22∶6 acid (DHA) lipid bilayers. Aβ(25–35) is the smallest fragment retaining the biological activity of the full-length peptide, whereas DOPC and DOPC/DHA lipid bilayers were selected as models of cell-membrane environments characterized by different fluidity. Our results provide evidence that in hydrophobic DOPC and DOPC/DHA lipid bilayers, Aβ(25-35) forms layered aggregates composed of mainly annular structures. The mutual interaction between annular structures and lipid surfaces end-results into a membrane solubilization. The presence of DHA as a membrane-fluidizing agent is essential to protect the membrane from damage caused by interactions with peptide aggregates; to reduces the bilayer defects where the delipidation process starts.

Subharmonic gap structures and Josephson effect in MgB2 /Nb microconstrictions

Superconducting micro-constrictions between Nb tips and high quality MgB

Observation of superconducting vortex clusters in S/F hybrids

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Pairing state in the ruthenocuprate superconductor Ru Sr 2 Gd Cu 2 O 8 : A point-contact Andreev reflection spectroscopy study

pellets have been realized by means of a point-contact inset, driven by a micrometric screw. Measurements of the current-voltage characteristics and of the dynamical conductance versus bias have been performed in the temperature range between 4.2 K and 500 K. Above the Nb critical temperature T

Andreev reflection in ferrimagnetic CoFe 2 O 4 spin filters

_{C}^{Nb}

POINT CONTACT STUDY OF THE SUPERCONDUCTING ORDER PARAMETER IN RuSr2GdCu2O8

, the conductance of the MgB

A Comparative Study of Different Tunnel Barriers for C-Axis Oriented Y(Ho)Ba2Cu3O7 Based Trilayer Structures

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Influence of a linear term on the density of states of high-Tc superconductors

/normal-metal constrictions behaves as predicted by the BTK model for low resistance contacts while high resistance junctions show quasiparticle tunneling characteristics. Consistently, from the whole set of data we infer the value

A phenomenological model for the analysis of tunneling experiments on 90 K and 60 K YBCO phases

Delta_{pi} = 2.5 pm 0.2