Highly photoresponsive monolayer-protected gold clusters by self-assembly of a cyclodextrin-azobenzene-derived supramolecular complex

Reversibly-photoswitchable gold nanoparticles containing azobenzene and exhibiting a light response "virtually identical" to that of the free chromophore were achieved by self-assembling a host-guest inclusion complex between alpha-cyclodextrin and an azobenzene-terminated alkanethiol in an aqueous medium.     

A numerical experiment of backward erosion piping: kinematics and micromechanics

Meccanica - We report on a numerical experiment by which we investigated the propagation of an erosion pipe in a water saturated granular soil. The simulation was performed with a two-dimensional...     

The instability of an axially loaded viscoelastic constrained bar in the large displacement range

Summary This paper deals with the behaviour of an axially loaded viscoelastic structure at one degree of freedom in the large deformation range; the stress-strain relation assumed is linearly viscoelastic, with the kernel at non invariant memory, typical of concrete.The study is rigorously conducted for two types of restraint, characterizing, in the elastic range, the instability of both first and second kind; the problem is then stated in respect of a type of mixed restraint, such as can be found in some real structures, an approximate solution of which is here supplied.

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Sommario Vengono analizzate le caratteristiche di comportamento nel tempo di una struttura viscoelastica a un grado di libertà, caricata di punta, nel campo delle grandi deformazioni; il legame sforzi-deformazioni assunto è viscoelastico lineare, con il nucleo a memoria non invariante caratteristico dei calcestruzzi.Lo studio è svolto in forma rigorosa per due tipi di vincolo che caratterizzano, in campo elastico, l'instabilità di prima e quella di seconda specie; viene inoltre impostato il problema corrispondente ad un tipo di vincolo misto, presentato da alcune strutture reali, del quale si fornisce una soluzione approssimata.

     

Amplified nitric oxide photorelease in DNA proximity

A novel bichromophoric conjugate integrating a NO photodonor and a DNA intercalator in its molecular skeleton, allows the light-controlled NO delivery nearby DNA and amplifies NO release via effective photoinduced energy transfer mechanism.     

Hyperelastic Multiphase Porous Media with Strain-Dependent Retention Laws

This article presents poroelastic laws accounting for a retention behavior dependent also on porosity, as suggested by experimental evidence. Motivated by the numerical formulation of the corresponding boundary-value problem presented in a companion article, these constitutive equations employ displacements and fluid pressures as primary variables. The thermodynamic admissibility of the proposed rate laws for stress and fluid contents is assessed by means of symmetry and Maxwell conditions obtained from the Biot theory. In the case of strain-dependent saturation, the two elasticity tensors describing the drained response in saturated and unsaturated conditions, respectively, are proven to be in general not coincident, with their difference depending on capillary pressure and porosity. Furthermore, it is shown that besides the stress decomposition proposed by Coussy, also the stress split proposed by Lewis and Schrefler is consistent with the Biot framework. The former decomposition is obtained for retention laws depending only on capillary pressure, as expected. The Lewis–Schrefler split is proven to be consistent with retention models depending also on porosity. In these developments, the compressibility of all the phases is taken into account, in order to assess the thermodynamic consistency of an extension of the Biot’s coefficient to partially saturated anisotropic porous media.