Biomedical subjects

Gianluca Malavasi

Publications and source records attributed to Gianluca Malavasi.

5 recordsLinked to original sources

PubMed2006

A new self-consistent empirical interatomic potential model for oxides, silicates, and silica-based glasses.

A new empirical pairwise potential model for ionic and semi-ionic oxides has been developed. Its transferability and reliability have been demonstrated by testing the potentials toward the prediction of structural and mechanical properties of a wide range of silicates of technological and geological importance. The partial ionic charge model with a Morse function is used, and it allows the modeling of the quenching of melts, silicate glasses, and inorganic crystals at high-pressure and high-temperature conditions. The results obtained by molecular dynamics and free energy calculations are discussed in relation to the prediction of structural and mechanical properties of a series of soda lime silicate glasses.

Journal Article↗

PubMed2005

A computational tool for the prediction of crystalline phases obtained from controlled crystallization of glasses.

An automatic tool (named CLUSTER) for the prediction of the most probable crystal phases that can separate from glasses has been developed. The program analyzes the output of molecular dynamics simulations of glasses or glass ceramics, systematically sampling the ratios of the ions in different portions of the simulation box and comparing them to the stoichiometric ratio of compositionally equivalent crystalline phases retrieved from a crystal structure database. The efficacy of the similarity index elaborated has been judged by comparing the results obtained with the crystal phases identified by XRD analysis after thermal treatment in a series of multicomponent potential bioactive glasses and glass ceramics for which the advantages of rational-designed erosion-controlled release is straightforward.

Journal Article↗

PubMed2005

Thermodynamic aspects of the adsorption of hexametaphosphate on kaolinite.

The adsorption of hexametaphosphate ion, an important deflocculant used in the ceramic industry, from aqueous solutions onto kaolinite has been studied at different temperatures. The adsorption isotherm follows the Langmuir model: the thermodynamic parameters DeltaG(ads)(0), DeltaH(ads)(0), and DeltaS(ads)(0) were calculated and found to be consistent with an interaction model involving the formation of an inner-sphere complex between HMP and aluminol groups. Also, the dependence of the adsorption behavior on the kaolinite volume fraction has been studied and discussed in term of association processes between the clay particles.

Adsorption↗

PubMed2005

Qualitative and quantitative structure-property relationships analysis of multicomponent potential bioglasses.

The results of a qualitative and quantitative structure-property relationships analysis of multicomponent potential bioglasses of composition (2 - y) SiO2 x 1 Na2O x 1.1 CaO x y P2O5 x x ZnO (x = 0, 0.16, 0.35, 0.78 and y = 0.10, 0.20, 0.36) are presented. Quantitative models are obtained by means of structural descriptors derived by molecular dynamics simulations and experimental data measured for density, thermal analysis, 29Si and 31P magic angle spinning NMR, and chemical durability in water. Analysis of the crystal species obtained upon glass crystallization helped in the rationalization of the structural role of the different components. Finally, glass surface characterization with scanning electron microscopy, transmission electron microscopy, and X-ray diffraction after soaking in acellular simulated body fluid demonstrated the in vitro bioactivity of the newly obtained 1.80 SiO2 x 1 Na2O x 1.1 Ca x 0.20 P2O5 x 0.16 ZnO (HP5Z5) glass, corresponding to x = 0.16 and y = 0.20.

Glass↗

PubMed2002

Removal of cadmium ion by means of synthetic hydroxyapatite.

The reaction behaviour of synthetic hydroxyapatite [Ca10(PO4)6(OH)2] (HAP) toward cadmium ion was investigated for the Cd/Ca molar ratio in the range 1-0.005, by means of ions, pH measurements and XRD, SEM, IR techniques. The reaction behaviour between HAP and cadmium ion could be explained by a formation of an amorphous phase and/or a sorption mechanism.

Adsorption↗