1,721,100 research outputs found
The effect of the incorporation of catalase mimetic activity cations on the structural, thermal and chemical durability properties of the 45S5 Bioglass®
No full textUnderstanding the effect of the incorporation of doping ions into the structure, thermal properties and chemical durability of bioactive glasses is fundamental for the design of new compositions with tailored biological functions and applications. In this work, we have applied a combined experimental and computational approach to unravel the effect of adding metal oxides of Ce, Ti, V, Mn, Fe, Co, Cu, and Zr that impart catalase mimetic activity to the 45S5 Bioglass® on its density, thermal properties and chemical durability. UV-Vis-NIR spectroscopy and temperature-programmed reduction (TPR) experiments allowed us to determine the oxidation states of the doping cations in the bulk of the glasses, Differential Thermal Analysis has been used to determine the glass transition and crystallization temperature, whereas the chemical durability in water was determined by following the hydrolytic resistance of glass grains at 98 °C standard method. The experimental results have been interpreted at the atomic level by exploiting reliable bulk and surface structural models of the investigated glasses generated by using Molecular Dynamics Simulations. Structure-property relationships helpful for the rational design of new glass compositions have also been inferred
What can we learn from atomistic simulations of bioactive glasses?
Full text linkIn the last decades, most experimental efforts have been devoted to design bioactive glasses (please consult the Editor’s note in order to clarify the usage of the terms bioglass, bioactive glass and biocompatible glasses) with enhanced biological and mechanical properties by adding specific ions to known bioactive compositions. Concurrently, computational research has been focused to the understanding of the relationships between bioactivity and composition by rationalization of the role of the doping ions. Thus, a deep knowledge of the structural organization of the constituent atoms of the bioactive glasses has been gained by the employment of ab initio and classical molecular dynamics simulations techniques. This chapter reviews the recent successes in this field by presenting, in a concise way, the structure–properties relationships of silicate, phospho-silicate and phosphate glasses with potential bioactive properties
Multiscale Molecular Dynamics Simulation of Multiple Protein Adsorption on Gold Nanoparticles
Full text linkA multiscale molecular dynamics simulation study has been carried out in order to provide in-depth information on the adsorption of hemoglobin, myoglobin, and trypsin over citrate-capped AuNPs of 15 nm diameter. In particular, determinants for single proteins adsorption and simultaneous adsorption of the three types of proteins considered have been studied by Coarse-Grained and Meso-Scale molecular simulations, respectively. The results, discussed in the light of the controversial experimental data reported in the current experimental literature, have provided a detailed description of the (i) recognition process, (ii) number of proteins involved in the early stages of corona formation, (iii) protein competition for AuNP adsorption, (iv) interaction modalities between AuNP and protein binding sites, and (v) protein structural preservation and alteration
Applications of machine-learning interatomic potentials for modeling ceramics, glass, and electrolytes: A review
No full textThe emergence of artificial intelligence has provided efficient methodologies to pursue innovative findings in material science. Over the past two decades, machine-learning potential (MLP) has emerged as an alternative technology to density functional theory (DFT) and classical molecular dynamics (CMD) simulations for computational modeling of materials and estimation of their properties. The MLP offers more efficient computation compared to DFT, while providing higher accuracy compared to CMD. This enables us to conduct more realistic simulations using models with more atoms and for longer simulation times. Indeed, the number of research studies utilizing MLPs has significantly increased since 2015, covering a broad range of materials and their structures, ranging from simple to complex, as well as various chemical and physical phenomena. As a result, there are high expectations for further applications of MLPs in the field of material science and industrial development. This review aims to summarize the applications, particularly in ceramics and glass science, and fundamental theories of MLPs to facilitate future progress and utilization. Finally, we provide a summary and discuss perspectives on the next challenges in the development and application of MLPs
Improved empirical force field for multicomponent oxide glasses and crystals
Full text linkIn this paper, the self-consistent PMMCS force fields (FFs) [Pedone et al., J. Phys. Chem. B 110, 11780 (2006)10.1021/jp0611018] widely used for the simulation of a large variety of silicates, aluminosilicate and phosphate crystals, and multicomponent oxide glasses have been revised and improved by the inclusion of two types of three-body interactions acting between T-O-T bridges (T=Si and P) and network former-network former repulsive interactions. The FFs named Bertani-Menziani-Pedone (BMP)-harm and BMP-shrm better reproduce the T-O-T bond angle distributions (BADs) and network former-oxygen distances. Consequently, the prediction of Qn distributions (Q stands for quaternary species, and n is the number of bridging oxygens around it), neutron total distribution functions, solid-state nuclear magnetic resonance spectra of spin active nuclei (Si29, O17, P31, Al27), and the density have also been hugely improved with respect to the previous version of our FF. These results also highlight the strong correlation between the T-O-T BADs and the other short and intermediate structural properties in oxide glasses, which have been largely neglected in the past. In addition to the improvement of the structure, the FF has been revealed to reproduce well the ionic conductivity in mixed alkali aluminosilicate glasses and the elastic properties. The systematic comparison with other interatomic potential models, including the polarizable core-shell model, carried out in this paper showed that our potential model is more balanced and effective for simulating a vast family of crystalline and amorphous oxide-based systems
Disclosing the interaction of gold nanoparticles with aβ(1–40) monomers through replica exchange molecular dynamics simulations
Full text linkAmyloid-β aggregation is one of the principal causes of amyloidogenic diseases that lead to the loss of neuronal cells and to cognitive impairments. The use of gold nanoparticles treating amyloidogenic diseases is a promising approach, because the chemistry of the gold surface can be tuned in order to have a specific binding, obtaining effective tools to control the aggregation. In this paper, we show, by means of Replica Exchange Solute Tempering Molecular Simulations, how electrostatic interactions drive the absorption of Amyloid-β monomers onto citrates-capped gold nanoparticles. Importantly, upon binding, amyloid monomers show a reduced propensity in forming β-sheets secondary structures that are characteristics of mature amyloid fibrils
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