Papers by Author: Roxana M. Piticescu

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Authors: Roxana M. Piticescu, Gabrielle Charlotte Chitanu, Aurelia Meghea, Maria Giurginca, Gabriela Negroiu, Laura Madalina Popescu
Abstract: A comparative study of the in situ interactions between different maleic anhydride based copolymers and calcium phosphates is presented in this paper. The ability of functional groups of the organic polymers to form under high pressure and low temperatures chemical bonds with the inorganic phase leading to improved properties of hybrid nanostructured material is discussed. The open challenges of new hybrid nanocomposites in the field of biomedical materials are evaluated. The challenge to use these nanostructured materials in medical field was evaluated by mapping the interface reactions between hybrid active layers and cells.
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Authors: Roxana M. Piticescu, Gabrielle Charlotte Chitanu, Mihaela Albulescu, Maria Giurginca, Madalina Laura Popescu, Witold Łojkowski
Abstract: The aim of the work is to establish if maleic anhydride copolymer acts as a grain growth modulator and/or as a biocompatible functionalisation agent for hydroxyapatite. Experimental work was developed in three directions: nanocomposites synthesis, nanocomposites characterization and citotoxicity tests on nanocomposites. Maleic anhydride copolymer – HAp nanocomposites were prepared by in situ functionalisation in hydrothermal conditions and were characterized by chemical quantitative analysis, XRD, FT-IR, SEM, specific surface area and picnometric densities. Chemical bonding between the copolymer carboxyl groups and calcium ions of HAp induced a peak of 1577 cm-1 on the FT-IR analysis. Following the evolution of this characteristic peak with the hydrothermal synthesis conditions (different temperatures and pressures) and corroborates the results with XRD and SEM analysis it was pointed out the copolymer grain growth modulator behaviour. Citotoxicity studies in vitro on mice fibroblast cultures were performed. The results proved the biocompatibility of new hybrid –polymer nanocomposites.
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Authors: Robert R. Piticescu, Roxana M. Piticescu, D. Taloi
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Authors: Roxana M. Piticescu, X. Granados, Anna E. Carrillo, C. Bogdanescu, D. Taloi
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Authors: Marco Actis Grande, Roxana M. Piticescu, C. Bogdanescu, Daniele Ugues, Mario Rosso
Abstract: Metal/ceramic composite materials were produced with core/shell structure by traditional pressing and the influence of the compacting parameters on the material properties has been studied. Different quantities of ceramic have been introduced to coat the base stainless steel powder. The use of a new generation of coated powders gives the opportunity to achieve near net shape massive composite exhibiting a composite microstructure, with a uniform dispersion of ceramic hard particles embedded in the metal matrix. Sintering was carried out in vacuum and at temperatures typical of metal sintering process (1250 °C). Microstructures of produced samples have been investigated through the use of LOM and SEM. Hardness as well as tensile and bending tests have been performed.
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Authors: Roxana M. Piticescu, Viorica Trandafir, V. Danciu, Z. Vuluga, Eugeniu Vasile, D. Iordachescu
Abstract: Many researchers have assumed that a combination of hydroxyl apatite (HAP) and collagen (COL) may be the best solution for bone replacement and have prepared their composites by several techniques [1]. However, such HAP/COL composite had no nanostructure similar to bone, and consequently indicated no bone-like mechanical properties. These results demonstrate that the chemical composition similar to bone only is insufficient for bone metabolism and mechanical properties. Mechanical and biological performance of this type of materials could be improved by adding TiO2 within the initial mixture of nanostructured composites [2]. Ternary nanostructured systems consisting of hydroxyl apatite, TiO2 aerogel and collagen were prepared for the first time by hydrothermal procedure in high pressure conditions. Among many advantages, the synthesis method proposed in this paper could lead to formation of chemically bonded compounds as a consequence of high pressure conditions. The resulted material could find applications in bone tissue regenerative medicine, either in powder form for bone defects treatment, or in matrix form as osteoconductive coating for metal implants. Further studies are necessary to evaluate the osteoconductive properties.
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