Study of the influence of plasticizers on the thermal and mechanical properties of poly(3-hydroxybutyrate) compounds

The influence of four types of plasticizers, dioctyl phthalate (DOP), dioctyl adipate (DOA), triacetyl glycerol (TAG) and polyadipate (PA), in the thermal and mechanical properties of Poly(3-hydroxybutyrate) (PHB), a highly crystalline biodegradable polyester, was evaluated in this work. The plasticizers were introduced alone or mixtures of them, using concentrations that varied from 5 to 30% wt. Their influence in some important polymer parameters as Tg, Tm and degree of crystallinity, and on its mechanical behavior, elongation and tensile strain were investigated. The best results were obtained for the sample with 30% TAG and that one using a binary mixture of plasticizers PA 20% and TAG 10%.     

Alginate Bioconjugate and Graphene Oxide in Multifunctional Hydrogels for Versatile Biomedical Applications

In this work, we combined electrically-conductive graphene oxide and a sodium alginate-caffeic acid conjugate, acting as a functional element, in an acrylate hydrogel network to obtain multifunctional materials designed to perform multiple tasks in biomedical research. The hybrid material was found to be well tolerated by human fibroblast lung cells (MRC-5) (viability higher than 94%) and able to modify its swelling properties upon application of an external electric field. Release experiments performed using lysozyme as the model drug, showed a pH and electro-responsive behavior, with higher release amounts and rated in physiological vs. acidic pH. Finally, the retainment of the antioxidant properties of caffeic acid upon conjugation and polymerization processes (Trolox equivalent antioxidant capacity values of 1.77 and 1.48, respectively) was used to quench the effect of hydrogen peroxide in a hydrogel-assisted lysozyme crystallization procedure.     

Transport in Quantum Multi-barrier Systems as Random Walks on a Lattice

Journal of Statistical Physics - Coulomb and log-gases are exchangeable singular Boltzmann–Gibbs measures appearing in mathematical physics at many places, in particular in random matrix...     

New restricted access materials combined to molecularly imprinted polymers for selective recognition/release in water media

A new restricted access materials combined to molecularly imprinted polymers (RAM-MIP) with hydrophilic external layer were prepared and their applicability in p-acetaminophenol (AMP) selective recognition and release was evaluated. Glycidilmethacrylate (GMA) was used as pro-hydrophilic co-monomer, and GMA epoxide ring opening with perchloric acid was performed for the hydrophilic modification of polymeric surface. Morphological and hydrophilic properties by scanning electron microscopy and water content measurement were determined and recognition and selectivity properties of RAM-MIP were compared to the unmodified MIP. With RAM-MIP, both hydrophobic non-specific interactions between template or its analogues and polymeric matrices, and bovine serum albumin absorption were drastically reduced.     

Transport properties of nanoperforated Nb thin films

Porous silicon, obtained by electrochemical etching, has been used as a substrate for the growth of nanoperforated Nb thin films. The films, deposited by UHV magnetron sputtering, inherited from the Si substrates their structure, made of holes of 10 nm diameter and of 20 and 40 nm spacing, which provide an artificial pinning lattice. Commensurability effects between the Abrikosov vortex lattice and the artificial array of holes were investigated by transport measurements.     

Guidelines for acoustical measurements in churches

The acoustics of churches is a cultural heritage to be preserved as carefully as the artistic and architectural aspects of this particular category of buildings. The acoustic characteristics of an environment could be measured according to different techniques varying from the numerical quantification, by means of acoustical parameters, to the recording of the binaural or ambisonic impulse responses of several combinations of source-receiver locations. The complexity of this kind of buildings can lead different researchers to choose dissimilar source-receiver arrangements, that yield incomparable results. To prevent different approaches to the problem and to assist in obtaining comparable data, the results of experimental measurements deriving from previous acoustical surveys are statistically analysed in order to better understand the spatial variation of acoustical parameters leading to the definition of a set of guidelines to standardize the choice of sources and receivers locations. In addition, suitable hardware combinations depending on the purpose of the measurement are finally suggested.     

Fick and Fokker–Planck Diffusion Law in Inhomogeneous Media

Journal of Statistical Physics - We discuss particle diffusion in a spatially inhomogeneous medium. From the microscopic viewpoint we consider independent particles randomly evolving on a lattice....     

Upscaling the interplay between diffusion and polynomial drifts through a composite thin strip with periodic microstructure

Meccanica - We study the upscaling of a system of many interacting particles through a heterogenous thin elongated obstacle as modeled via a two-dimensional diffusion problem with a one-directional...     

Versatile and self-assembling urea-linked neosaccharides from sugar aminoalcohols

The increasing interest in urea compounds as self-assembling molecules, ion transporters and organocatalysts prompted several efforts towards synthetic urea-linked glycomimetics. In this frame we studied in details a novel two steps dimerization reaction of sugar vicinal aminoalcohol building blocks, opening a synthetic path to a series of urea-linked neosaccharides. Glucosamine neodisaccharide possessing an oxazolidinone–urea–oxazolidinone system could be transformed into both cyclic and higher linear neosaccharides. Furthermore, a series of six urea-linked glucosamine and galactosamine neodisaccharides was tested for self-assembling properties by measuring NMR spectra at different temperatures and concentrations as well as by gelation of several organic solvents.