Pore geometry of ceramic device: The key factor of drug release kinetics

Release kinetics of tigecycline, a potential antibiotic in treatment of osteomyelitis, from calcium hydroxyapatite (CHA), as one of the most important ceramic materials in bone tissue engineering, was investigated in this study. Tigecycline, in solid state, was mixed with CHA powder and the obtained mixture was compressed into tablets using two different pressures. These tablets were immersed in a phosphate-buffered saline solution and tigecycline release was measured by a UV-VIS spectrophotometer. The total release time was 5 or 28 days, depending on the pressure applied during compression. It was shown that there is a close relationship between pore sizes and drug release rate. The drug release kinetics was interpreted on the base of pore sizes and pore size distribution. [Projekat Ministarstva nauke Republike Srbije, br. 172026

PO-410 Cytotoxicity and genotoxicity of new gadolinium, iron oxide, cobalt ferrite and graphene oxide nanoparticles on some tumour cell lines in vitro

Nanoparticles (NPs) are increasingly used in cancer therapy as delivery agents and in the diagnosis of malignant diseases as contrast agents for magnetic resonance imaging (MRI). The aim of this work was in vitro assessments of Gd-NPs, Fe- NPs, CoFe-NPs and Graphene Oxide-NPs cytotoxicity and genotoxicity on some tumour and normal human cell lines.Abstracts of the 25th Biennial Congress of the European Association for Cancer Research, Amsterdam, The Netherlands, 30 June – 3 July 201

Room-Temperature Ferromagnetism in Zn-Mn-O, X-Ray Photoemission Surface Study

Room temperature ferromagnetic properties of Zn-Mn-O show evident dependence on manganese concentration and preparation conditions. We systematically studied series of samples with manganese concentration ranging from 0 to 10 at.%, prepared in air at thermal treatment temperatures ranging from 400 to 900°C. The samples were investigated by X-ray diffraction, TEM, magnetization measurements and XPS spectroscopy. XPS analyses of surface composition, chemical bonding and XPS depth profiling were successfully employed on powder revealing the chemical composition at the surface of the grains and underneath. The study emphasizes important role of the grain surface in observed room temperature ferromagnetism. It seems that the ferromagnetic phase is correlated with oxygen build up at the surface

Ferromagnetic properties of the Zn-Mn-Osystem

Polycrystalline Zn -Mn -O samples with nominal manganese concentration x = 0.01 and 0.10 were synthesized by a solid state reaction route using (ZnC(2)O(4) center dot 2H(2)O)(1-x) and (MnC(2)O(4) center dot 2H(2)O)(x). Thermal treatment of the samples was carried out in air at temperatures of 673, 773 and 1173 K. The samples were investigated by x-ray diffraction, thermogravimetry, differential thermal analysis, transmission electron microscopy, magnetization measurements and electron paramagnetic resonance. Room temperature ferromagnetism is observed in Zn -Mn -O samples with x = 0.01 thermally treated at low temperatures (673, 773 K). It seems that the ferromagnetic phase could originate from interactions between Mn(2+) ions and acceptor defects incorporated in the ZnO crystal lattice during the thermal treatment of the samples

Sol-gel as a method to tailor the magnetic properties of Co1+yAl2-yO4

The magnetic properties of mesoscopic materials are modified by size and surface effects. We present a sol-gel method used to tailor these effects, and illustrate it on Co1+yAl2-yO4 spinel. Nanocomposites made of spinel oxide Co1+yAl2-yO4 particles dispersed in an amorphous SiO2 matrix were synthesized. Samples with various mass fractions -x of Co1+yAl2-yO4 in composite, ranging from predominantly SiO2 (x = 10 wt%) to predominantly spinel (x = 95 wt%), and with various Co concentrations in spinel y were studied. The spinel grain sizes were below 100 nm with a large size distribution, for samples with predominant spinel phase. Those samples showed Curie-Weiss paramagnetic behavior with antiferromagnetically interacting Co ions (θ ≈ -100 K). The grain sizes of spinel stays confined in 100 nm range even in the spinel samples diluted with as low as 5 wt% concentration of amorphous SiO2. For the samples with predominant SiO2 the crystalline nanoparticles are well separated and of size of around 100 nm, but with presence of much smaller spinel nanoparticles of about 10 nm. The magnetic properties of the samples with predominant silica phase showed complex behavior, spin-glass magnetic freezing at the lowest temperatures and lower absolute value of θ and consequently lower exchange constant. [Projekat Ministarstva nauke Republike Srbije, br. 172026

Methods of purification and characterization of carbon nanotubes

In an attempt to purify MWNT in mild conditions, we have applied two different methods of purification. The first method of purifying the material was a combination of relatively often used methods, such as etching and acid treatment, and the second method was a relatively new one, using an organic polymer PmPV. Sample purity was obtained with SEM and ESR techniques

Methods of purification and characterization of carbon nanotubes

In an attempt to purify MWNT in mild conditions, we have applied two different methods of purification. The first method of purifying the material was a combination of relatively often used methods, such as etching and acid treatment, and the second method was a relatively new one, using an organic polymer PmPV. Sample purity was obtained with SEM and ESR techniques