Central limit behavior in the Kuramoto model at the “edge of chaos”

We study the relationship between chaotic behavior and the Central Limit Theorem (CLT) in the Kuramoto model. We calculate sums of angles at equidistant times along deterministic trajectories of single oscillators and we show that, when chaos is sufficiently strong, the Pdfs of the sums tend to a Gaussian, consistently with the standard CLT. On the other hand, when the system is at the “edge of chaos” (i.e. in a regime with vanishing Lyapunov exponents), robust q-Gaussian-like limit distributions naturally emerge, consistently with recently proved generalizations of the CLT.     

Synthesis of Poly(acrylic acid) Nanogels and Application in Loading and Release of an Oligothiophene Fluorophore and Its Bovine Serum Albumin Conjugate

Summary: Nanometer-sized poly(acrylic acid) (PAA) hydrogels were synthesized by emulsion polymerization of methyl acrylate and subsequent acid hydrolysis, and their pH-dependent swelling behaviour was studied by dynamic light scattering. To determine the suitability of PAA nanogels as pH-sensitive carriers for biomedical applications, loading and release of an oligothiophene fluorophore and its albumin conjugate onto the PAA nanogels were investigated as a function of pH by absorption and photoluminescence measurements. It was observed that loading and release processes of both the oligothiophene and its conjugate could be controlled by changing pH of their solutions.     

Buckling of an elastic hemispherical shell with an obstacle

We study the buckling of an axially symmetric elastic hemispherical shell, uniformly compressed, subject to a constraint to the radial shifting of the equatorial circumference. The static equilibrium equations, using tensorial notations, are obtained applying the virtual displacements principle to the energy functional. The presence of a constraint does not modify the field equations with respect to the case of a constraint-free buckling, but only influences the boundary conditions, so that, instead of a boundary value problem, we deal with a problem with complementarity conditions on the boundary. We revisit and improve some previously obtained mathematical results, adapting them for the subsequent numerical treatment. Finally, by suitably using a delicate quasi-static shooting technique, numerical results are obtained, which complete the theoretical analysis and give an interesting insight into the behavior of the bifurcation branches.     

Continuous Dependence on Initial Data in Fluid–Structure Motions

We prove a continuous dependence theorem for weak solutions of equations governing a fluid–structure interaction problem in two spatial dimensions. The proof is based on a priori estimates which, in particular, convey uniqueness of weak solutions. The estimates are obtained using Eulerian coordinates, without remapping the problem into a fixed domain.     

Brønsted Base Catalyzed One‐Pot Synthesis of Stereodefined Six‐Member Carbocycles Featuring Transient Trienolates and a Key Intramolecular 1,6‐Addition

A catalyst‐driven one‐pot reaction sequence is developed for the enantio‐ and diastereoselective synthesis of tetrasubstituted cyclohexenes from simple unsaturated ketones or thioesters. The method involves a tertiary amine/squaramide‐catalyzed α‐selective addition of transiently generated trienolates to nitroolefins, subsequent base‐catalyzed double bond isomerization, and an intramolecular (vinylogous) 1,6‐addition reaction, a rare key carbocyclization step that proceeded with essentially perfect stereocontrol.     

Electrochemical Detection of Vascular Endothelial Growth Factor by Molecularly Imprinted Polymer

In this study, we report the development of a sensitive label‐free impedimetric sensor based on molecularly imprinted polymer (MIP) as biomimetic receptor coupled with screen‐printed electrodes (SPEs) for the detection of vascular endothelial growth factor (VEGF). Firstly, electropolymerization of o‐phenylenediamine (o‐PD) in the presence of VEGF molecule by cyclic voltammetry was performed onto graphite screen‐printed electrodes. The solvent extraction of the target was then carried out. The MIP based sensor was characterized by electrochemical techniques and scanning electron microscopy (SEM). Using optimized experimental conditions, the single‐use MIP‐based sensor showed a good analytical performance for VEGF detection from 20 to 200 pg mL^?1 with limit of detection of 0.08 pg mL^?1. Finally, the developed MIP‐based sensor in human serum samples was also tested.     

Laser-induced fragmentation of transition metal nanoparticles in ionic liquids

Stable Pd(0) and Rh(0) nanoparticles with small and narrow size distribution can be prepared from relative large and agglomerated transition-metal particles dispersed in 1-n-butyl-3methylimidazolium hexafluorophosphate ionic liquid by simple laser irradiation. The laser irradiation is a complementary method for the generation of stable metal colloids in ionic liquids and also for the regeneration of small-size nanoparticles that may result from their agglomeration after different applications.     

Effect of surfactant phase transition on the inclusion behaviour of an amphiphilised porphyrin derivative

The macroscopic morphology of a micelle biomembrane model strongly affects the aggregation state of an included porphyrin derivative.     

Wave features for consistent-order-extended thermodynamics

Linear and nonlinear waves propagating in a heat conductive gas described by Consistent-Order-Extended Thermodynamics of third order are studied. Firstly, the propagation of plane harmonic waves are analyzed and the frequency dependence of the phase velocity and of the attenuation is shown. Furthermore, our results are compared with the ones obtained in the context of Extended Thermodynamics at thirteen moments and with the experimental data. Finally, the propagation of acceleration waves is studied. The amplitude equation of the fastest mode is derived and the critical time is evaluated. (Received: November 17, 2004)     

Topics on Variational Analysis and Applications to Equilibrium Problems

We observe how many equilibrium problems obey a generalized complementarity condition, which in general leads to a variational inequality. We illustrate this fact, by studying the elastic–plastic torsion problem and finding the related Lagrange multipliers.