Showing 3 results for Yousefpour
M. Yousefpour,, A. Zareidoost , A. Amanzadeh,
Volume 30, Issue 1 (Jun 2011)
Abstract
The osseointegration of oral implants is related to the early interactions between osteoblastic cells and titanium surface. Chemical surface modification of titanium (Ti) implants is used to improve peri-implant bone growth, bone-to-implant contact, and adhesion strength. Thus, in this study, the surface topography, chemistry, and biocompatibility of polished titanium surface treated with mixed solution of three acids containing hydrochloric acid (HCl)- hydrofluoric acid (HF)- phosphoric acid (H3PO4) were studied under different concentration conditions. Moreover, Osteoblast cell (MG-63) was cultured on the and treated polished titanium surface. Also, in order to investigate titanium surface, SEM, AFM and EDS analyses were carried out. The results revealed that the surface of titanium treated with mixed solution containing the aforesaid acids had higher roughness, cell attachment, and proliferation than the controls
Z. Taherian, M. A. Yousefpour, M. A. Faghihi Sani, A. Nemati,
Volume 31, Issue 1 (Jun 2012)
Abstract
The aim of this work was synthesis of MCM-41/HA nanocomposite and biodegradation behavior of pure silica-mesoporous in attendance of hydroxyapatite crystals. These materials were synthsized by sol-gel method and ageing at 100°C for 24hr. A surfactant was used as template. The pores were formed after removal of surfactant by calcination at 550°C. FTIR results demonstrated formation of silanol and siloxan groups of silica network and hydroxyl and phosphate groups of HA network. Also SEM, TEM and EDS results confirmed presence of HA crystals within MCM-41 structure. Finally biodegradation behavior was examined by ICP and FTIR analysis. The results indicated biodegradable HA phase in the nanocomposite (with release of Ca2+ inos in water and the increasing of the pH value) can increase non-bridging oxygens of the silica network and therefore, it improves biodegradation behavior of silica network.
M.a. Yousefpour, F. Safari Kooshali, B. Khoshandam,
Volume 34, Issue 3 (Journal of Advanced Materials-fall 2015)
Abstract
The purpose of this work was to study the hydrogen adsorption on the surface of mesoporous materials based on silica (SBA-16) modified with palladium via temperature. Since mesoporous silica materials have a high specific surface area, and the ordered mesoporous size of 2-10nm, they are suitable for adsorption and storage of hydrogen. SBA-16 is suitable for this purpose due to its cubic crystalstructure and open pores. Single-stage sol-gel method was used to produce nanostructure composite from salt of palladium (PdCl3) and mesoporous silica precursor. The aging time was selected as 12 hr at 80˚C. Furthermore, the obtained materials were heated at 550˚C for 6 hr to remove surfactant and to form pores. Then the materials were characterized by large angle and small angle x-ray diffraction analysis, and hydrogen absorption analysis at upto 200kPa pressure at three different temperatures of -196˚C (77 K), -123˚C (150 K) and 30˚C (303 K). Furthermore, adsorption-desorption of nitrogen gas was studied. The surface morphology was observed by field emission scanning electron microscope (FESEM). In addition, the amount of palladium, oxygen, and silicon were measured by using energy dispersive spectroscopy) EDS ). Finally, the functional groups on the surface of mesoporous silica materials were evaluated using Fourier transform infrared spectroscopy (FTIR). The results of XRD and EDS analyses confirmed the presence of palladium and palladium oxide in mesoporous amorphous silica. In addition, BET results showed that addition of palladium in SBA-16 decreased the surface area, and produced 791 and 538m2/g for SBA-16 and SBA-16/Pd, respectively. Hydrogen absorption in nano structure composite was decreasing with temperatur in comparison with SAB-16. On the other hand, the maximum hydrogen absorption in the nano structure composite containing palladium was obtained at -196˚C (77 K).
