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In this study, we investigated the behaviors and cytocompatibility response of human cervical carcinoma (HeLa) cells expose to nano-sized particles. Cultivated cells exposed to titanium oxide and indium oxide nanoparticles remained highly viable. In the presence of copper oxide (CuO); however, the cells became seriously inflamed. To understand the mechanism by which CuO causes cell death, we evaluated cell death and apoptosis cytometry. CuO induced cells apoptosis more strongly than exposure to titania nanoparticles. Confocal fluorescence microscopy revealed that the nano-sized particles penetrate the cells.

We assessed the biocompatibility of nano-sized ceramic particles with several cells types. Though these particles have less than 100 nm in diameter, they act as submicron-sized particles in saline by aggregation that was estimated using laser diffraction particle size analysis (LDS). they act as submicro-sized particles in saline by aggregation based on laser diffraction particle size analysis (LDS). Several types of cells (osteoblasts, osteosarcoma and hepatocyte cells) were exposed to these particles and their cytocompatibility was estimated. Not only the cytotoxic assay but also their static and dynamic morphology under nanoparticles exposure were investigated. The intercellular uptake of particles was determined using a confocal fluorescence microscope. The particles used in this study did not inhibit cellular activity or growth even when their concentrations were high. Only copper oxide particles caused acute cytotoxicity depending on the particle size. The cytotoxicity assay, dynamic behavior of the nanoparticle-exposed cells and their examination under a confocal fluorescence microscope suggests that the irritative reaction was induced by contact between the cells and particles, whereas eluted copper ions are not dominant factor. These results indicate that nano-sized particles used in this study have excellent biocompatibility except copper oxide ones.

The purpose of the present study was to investigate the validity of incorporating a para-periodontal ligament in the test mold used in a basic fracture test of a zirconia all-ceramic fixed partial denture (FPD). A simplified three-dimensional finite element analysis model was designed based on the three-unit FPD fracture test. Two types of model, one with and one without a para-periodontal ligament between the abutment and base mold, were fabricated. Microfocus CT of the missing first molar area in a dry human mandible was performed. A three-dimensional model was then fabricated based on the data obtained. A load of 600 N was applied to the center of the pontic and stress distribution observed. The model with the para-periodontal ligament showed stress dispersion to the dental root with rotation of the abutment mold. Stress distribution in the finite element analysis model with a para-periodontal ligament showed greater similarity with that in the mandibular model than with that in the other two models without a para-periodontal ligament.

Trivalent rare-earth (RE = Eu, Sm) doped transparent nano-glass–ceramics comprising BaYF 5 nanocrystals were successfully obtained by appropriate heat-treatment of the corresponding precursor sol–gel glasses. Their structural and spectroscopic properties were investigated and compared with those for Eu 3+ -doped-BaYF 5 nanocrystals prepared by a solvothermal method. X-ray Diffraction, Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy measurements confirmed the distribution of BaYF 5 nanocrystals in the glass matrix, presenting a cubic phase structure with space group Fm - 3m . In order to achieve a further structural characterization, the luminescence properties of the Eu 3+ and Sm 3+ dopants were also used as sensitive probes. The reduction in the emission intensities of hypersensitive transitions 5 D 0 → 7 F 2 and 4 G 5/2 → 6 H 9/2 for Eu 3+ and Sm 3+ ions respectively, along with time-resolved measurements, confirm the distribution of a significant fraction of RE ions into the fluoride nanocrystal environment. These results suggest that BaYF 5 nano-glass–ceramics doped with Eu 3+ or Sm 3+ can be considered as potential red-emitting phosphors for the development of white LEDs under near UV excitation. [ABSTRACT FROM AUTHOR]