Ferroelectric Tunnel Junction for Dense Cross-Point Arrays.

Cross-point array (CPA) structure memories using a memristor are attracting a great deal of attention due to their high density integration with a 4F2 cell. However, a common significant drawback of the CPA configuration is crosstalk between cells. To date, the CPA structure using a redox-based memristor has restrictions to minimize the operating current level due to their resistive switching mechanism.

Macromolecular crowding: chemistry and physics meet biology (Ascona, Switzerland, 10-14 June 2012).

More than 60 years of biochemical and biophysical studies have accustomed us to think of proteins as highly purified entities that act in isolation, more or less freely diffusing until they find their cognate partner to bind to. While in vitro experiments that reproduce these conditions largely remain the only way to investigate the intrinsic properties of molecules, this approach ignores an important factor: in their natural milieu , proteins are surrounded by several other molecules of different chemical nature, and this crowded environment can considerably modify their behaviour. About 40% of the cellular volume on average is occupied by all sorts of molecules.

Surfactant adsorption onto interfaces: measuring the surface excess in time.

We propose a direct method to measure the equilibrium and dynamic surface properties of surfactant solutions with very low critical micellar concentrations (CMC) using a pendant drop tensiometer. We studied solutions of the nonionic surfactant hexaethylene glycol monododecyl ether (C(12)E(6)) and of the ionic surfactant hexadecyl trimethyl ammonium bromide (CTAB) with concentrated sodium bromide (NaBr). The variation of the surface tension as a function of surface concentration is obtained easily without the need for complex models and compares well with the result obtained using the Gibbs adsorption equation.

Rheological behaviour of polyoxometalate-doped lyotropic lamellar phases.

We study the influence of nanoparticle doping on the lyotropic liquid crystalline phase of the industrial surfactant Brij®30 (C₁₂E₄) and water, doped with spherical polyoxometalate nanoparticles smaller than the characteristic dimensions of the host lamellar phase. We present viscometry and in situ rheology coupled with small-angle X-ray scattering data that show that, with increasing doping concentration, the nanoparticles act to decrease the shear viscosity of the lamellar phase, and that a shear-induced transition to a multilamellar vesicle "onion" phase is pushed to higher shear rates, and in some cases completely suppressed. X-ray data reveal that the nanoparticles remain encapsulated within the membranes of the vesicles, thus indicating a viable method for the fabrication of nanoparticle incorporating organic vesicles.

Disordered one-dimensional bose-fermi mixtures: the Bose-Fermi glass.

We analyze an interacting Bose-Fermi mixture in a 1D disordered potential by using a combination of renormalization group and variational methods. We obtain the complete phase diagram in the incommensurate case as a function of bosonic and interspecies interaction strengths, in the weak disorder limit. We find that the system is characterized by several phase transitions between superfluid and various glassy insulating states, including a new Bose-Fermi glass phase, where both species are coupled and localized.

Confinement of DNA in water-in-oil microemulsions.

The study of systems that allow DNA condensation in confined environments is an important task in producing cell-mimicking microreactors capable of biochemical activities. The water droplets formed in water-in-oil emulsions are potentially good candidates for such microcompartments. The anionic surfactant AOT was used here to stabilize the droplets.

Domain growth dynamics and local viscosity in stratifying foam films.

We present a quantitative theory and experiments for the expansion dynamics of domains in stratifying foam films. Foam films containing micelles, colloidal particles or polymer-surfactant complexes often form layered structures and thin in a stepwise fashion: circular domains of lower thickness are formed and expand following a R(t) proportional variant t1/2 law. In the present paper the film is modeled by an incompressible three-dimensional fluid with incompressible surfaces.