Biomedical subjects

L de Arcangelis

Publications and source records attributed to L de Arcangelis.

4 recordsLinked to original sources

PubMed2006

Kinetics of bond formation in cross-linked gelatin gels.

In chemical cross-linking of gelatin solutions, two different time scales affect the kinetics of the gel formation in the experiments. We complement the experimental study with Monte Carlo numerical simulations of a lattice model. This approach shows that the two characteristic time scales are related to the formation of single bond cross-linker-chain and of bridges between chains. In particular, their ratio turns out to control the kinetics of the gel formation. We discuss the effect of the concentration of chains. Finally our results suggest that by varying the probability of forming bridges as an independent parameter, one can finely tune the kinetics of the gelation via the ratio of the two characteristic times.

Calorimetry↗

PubMed2006

Complex viscosity behavior and cluster formation in attractive colloidal systems.

The increase in viscosity that is observed in attractive colloidal systems by varying the temperature or the volume fraction can be related to the formation of structures due to particle aggregation. In particular we have studied the nontrivial dependence of the viscosity from the temperature and the volume fraction in the copolymer-micellar system L64. The comparison of the experimental data with the results of numerical simulations in a simple model for gelation phenomena suggests that this intriguing behavior can be explained in terms of cluster formation and that this picture can be quite generally extended to other attractive colloidal systems.

Journal Article↗

PubMed2006

Universality in solar flare and earthquake occurrence.

Earthquakes and solar flares are phenomena involving huge and rapid releases of energy characterized by complex temporal occurrence. By analyzing available experimental catalogs, we show that the stochastic processes underlying these apparently different phenomena have universal properties. Namely, both problems exhibit the same distributions of sizes, interoccurrence times, and the same temporal clustering: We find after flare sequences with power law temporal correlations as the Omori law for seismic sequences. The observed universality suggests a common approach to the interpretation of both phenomena in terms of the same driving physical mechanism.

Journal Article↗

PubMed2002

Complex dynamics in gelling systems.

We study the viscoelastic properties and the relaxation process in a gelling system by means of a minimal statistical-mechanics model. The model is based on percolation and bond fluctuation dynamics. The values for the critical exponents of the viscosity and elasticity agree with a part of the experimental observations and of the theoretical predictions. The obtained relaxation patterns well reproduce the behaviour observed in different gelling systems.

Journal Article↗